College of Agriculture, Engineering and Science · The College of Agriculture, Engineering and...

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College of Agriculture, Engineering and Science Postgraduate Research Day 2014 Westville Campus

The College of Agriculture, Engineering and Science would like to express its grateful

thanks to the following external partners of the 2014 College Postgraduate Research Day:

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thanks to the following exhibitors at the 2014 College Postgraduate Research Day:

CHEMIN

CSIR

DEPARTMENT OF WATER AND SANITATION, KZN REGION

ETHEKWINI MUNICIPALITY

KZN DEPARTMENT OF AGRICULTURE AND RURAL DEVELOPMENT

ILLOVO SUGAR

INQABA BIOTEC

INVOTECH

MONITORING CONTROL LABORATORIES

NATIONAL RESEARCH FOUNDATION

REUTECH COMMUNICATIONS

TECHNOLOGY AND HUMAN RESOURCES FOR INDUSTRY PROGRAMME

TRANSNET

UNILEVER

WATER RESEARCH COMMISSION

WHITEHEAD SCIENTIFIC

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thanks to the following judges of the 2014 College Postgraduate Research Day:

Dr Saumitra Misra – UKZN School of Agricultural, Earth & Environmental Sciences Professor Serban Proches– UKZN School of Agricultural, Earth & Environmental Sciences Dr Muthulisi Siwela – UKZN School of Agricultural, Earth & Environmental Sciences Dr Edilegnaw Wale – UKZN School of Agricultural, Earth & Environmental Sciences Professor Bice Martincigh – UKZN School of Chemistry & Physics Dr Genene Mola – UKZN School of Chemistry & Physics Dr Brenda Moodley – UKZN School of Chemistry & Physics Dr Mervlyn Moodley – UKZN School of Chemistry & Physics Dr Nolwazi Nombona – UKZN School of Chemistry & Physics Dr Bernard Owaga – UKZN School of Chemistry & Physics Dr Vino Paideya – UKZN School of Chemistry & Physics Dr Giuseppe Pellicane – UKZN School of Chemistry & Physics Dr Letitia Pillay – UKZN School of Chemistry & Physics Dr Karin Pruessner – UKZN School of Chemistry & Physics Mr Iain Kerr – UKZN School of Engineering Mr Mbuyu Ntunka – UKZN School of Engineering Dr Khalid Osman – UKZN School of Engineering Professor Jules-Raymond Tapamo – UKZN School of Engineering Dr Taurai Mutanda – UKZN School of Life Sciences Dr Yougasphree Naidoo – UKZN School of Life Sciences Professor Norman Pammenter – UKZN School of Life Sciences Dr Shakira Shaik – UKZN School of Life Sciences Dr Kanagaratman Arunakirinathar – UKZN School of Mathematics, Statistics & Computer

Science Professor Fortune Massamba – UKZN School of Mathematics, Statistics & Computer

Science Professor Glenda Mathews– UKZN School of Mathematics, Statistics & Computer Science Dr Deshen Moodley – UKZN School of Mathematics, Statistics & Computer Science

Mr Steven Weerts – Council for Scientific & Industrial Research Mr Eamon Bussy – Durban University of Technology Dr Rob Stephen – Eskom Ms Sigrun Amman – KZN Department of Agriculture and Rural Development

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Mr Guy Thibaud – KZN Department of Agriculture and Rural Development Dr Zolani Dyosi – National Research Foundation Dr Pat Naidoo - Pat Naidoo Consulting Engineers Dr Xolisa Melamane – Technology Innovation Agency Mr Alan Kockott – Umgeni Water Dr Sudhir Pillay – Water Research Commission


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College of Agriculture, Engineering and Science Post-Graduate Research Day 2014 Westville

PROGRAMME

Monday 27 October 2014, T Block Lecture Theatre Complex

08:30 - 08:55 Registration (T Block Lecture Theatre Complex Downstairs Foyer)

09:00 - 09:10 Introduction (T4 Lecture Theatre)

Dr Faraimunashe Chirove, School of Mathematics, Statistics & Computer Science

Opening and Welcome

Professor Jonathan Blackledge, Deputy Vice-Chancellor: Research, UKZN

09:10 - 09:40 Keynote Lecture (T4 Lecture Theatre)

Professor Kesh Govinder, Dean and Head of the School of Mathematics, Statistics and Computer Science, UKZN:

A Symmetric View of Life.

09:50-11:10 Session 1 Student Oral Presentations

Venue T4 T5 T6 T7

09:50 -10:10

A1:Joseph

Malinzi

B1: Andrew C.

Eloka-Eboka

C1: Phumelele

Kunene

D1: Siphelele

Mafuleka

10:10 - 10:30 A2: Maria Schuld B2: Nteseng

Ramoraswi

C2: Oluwaseun

A. Oyetade

D2: Londiwe

Magagula

10:30 - 10:50 A3: Tendai. M.

Mudziiri

Shumba

B3: Lucy M.

Ombaka

C3: Awonke

Mbangi

D3: George

Nyamato

10:50- 11:10 A4: Temitope

Mapayi

B4: Nomali

Ngobese

C4: Nhlanhla

Shabalala

D4: Chandika

Ramlall

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11:10 – 11:40 Tea Break

11:40 – 13:00 Session 2 Student Oral Presentations

Venue T4 T5 T6 T7

11:40 - 12:00 A5: Heather

Prince

B5: Matthew

Lasich

C5: Masande

Katamzi

D5: Chika

Chukwuma

12:00- 12:20 A6: Justine,

Nasejje

B6: Ray Leroy

Khuboni

C6: Stephanie

Vivien

Hayman

D6: Cassandra

Naidoo

12:20 -12:40 A7: Komi

Afassinou

B7: Theodora

Lamula

C7: Elkhatab

Abdalla

D7: Lauren

Eyssen

12:40 – 13:00 A8: Olumuyiwa

Otegbeye

B8: Usiholo Iruansi C8: Nyasha

Chiuraise

D8: Adriana

Marais

13:00 – 14:00 LUNCH & Poster Viewing

14:00 – 15:20 Session 3 Student Oral Presentations Venue T4 T5 T6 T7

14:00- 14:20

A9: Njoku Chima

B9: Meshack Sitati

C9: Macdex

Mutema

D9: Aminu

Mohammed

14:20 – 14:40

A10: Khayelihle

Xulu

B10: Olusula

Bodede

C10;Humbelani

Thenga

D10: Doty

Okanda

14: 40- 15:00

A11: Vusi

Mpendulo

Magagula

B11: Malekeng

Sylvester

Selala

C11: Tendai Polite

Chibarabada

D11: Oluwole

Samuel

Aremu

15:00 – 15:20

A12: Simo

Mthethwa

B12: Oyebode

Kazeem

C12: Jean

Nepomuscene

Namugize

D12: Kambaj

Olivier

Kambol

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15:20 - 15:50 Finalisation of Judging and Tea

15:50 - 16:20 Prize-Giving (T4 Lecture Theatre)

Professor Deo Jaganyi, Deputy Vice-Chancellor and Head of College: Agriculture, Engineering and Science, UKZN

16:20 – 16:30 Lucky Draw

16:30 Closing

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Keynote Lecture

A Symmetric View of Life By

PROFESSOR KESH GOVINDER - DEAN AND HEAD OF SCHOOL:

MATHEMATICS, STATISTICS AND COMPUTER SCIENCE, UKZN

Abstract:

The concept of symmetry has been exploited throughout history in order to solve various scientific

problems in a straightforward and simple manner. Indeed, it is remarkable how much symmetry exists

in nature and how this does help simplify problems. In this talk, I will present various applications of

symmetry to both physical and mathematical problems (current and historical). I will draw on

examples from simple geometry to chemistry, from everyday applications to physics. Some

applications of the concept of synchronization with also be explored.

Biography:

Kesh Govinder is a professor of Applied Mathematics at the

University of KwaZulu-Natal. His research is focussed on

differential equations (his motto: “have equations, will travel”). He

develops and extends techniques for analysing and solving both

ordinary and partial differential equations. These techniques involve

group theory, singularity analysis and dynamical systems analysis. In

addition he tackles applications of differential equations in

Mathematical Physics (mainly General Relativity and Gravitation) as

well as Mathematical Biology.

Kesh has authored in excess of 80 full length publications in international journals. He has also

presented (or co-presented) over 85 seminars and conference papers throughout the world. He has

travelled extensively visiting institutions in Australia, India, France, Greece and the United States

amongst other countries with active collaborations with researchers in India and the United States, as

well as in South Africa. In addition, he has helped organised a number of conferences and special

sessions in conferences. He has graduated 24 postgraduate students and is currently supervising

another 18.

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ORAL PRESENTATIONS (T4 Lecture Theatre)

Time

T4 Lecture Theatre

Title

Session 1 Chair: Prof Fortune Massamba

09:50 - 10:10

A1: Joseph Malinzi School of Mathematics, Statistics and Computer Science

Analysis Of Virotherapy In Solid Tumor Invasion

10:10 - 10:30 A2: Maria Schuld School of Chemistry and Physics

Quantum Machine Learning And Its Application In Data Mining

10:30 - 10:50

A3: Tendai. M. Mudziiri Shumba School of Mathematics, Statistics and Computer Science

On The Existence Of Self-Dual Codes Invariant Under Permutation Groups

10:50 - 11:10

A4: Temitope Mapayi School of Mathematics, Statistics and Computer Science

Robust Detection Of Vessels In Retinal Images Using Difference Image And K-Means Clustering Technique


11:40 - 12:00

A5: Heather Prince School of Mathematics, Statistics and Computer Science

Real Space Lensing Reconstruction Using Cmb Temperature And Polarisation

12:00 - 12:20

A6: Justine, Nasejje School of Mathematics, Statistics and Computer Science

Bayesian Frailty Modeling Using The Integrated Nested Laplace: An Application To Under-Five Child Mortality In Uganda.

12:20 - 12:40

A7: Komi Afassinou School of Mathematics, Statistics and Computer Science

Multiple Control Strategies On HIV Infection

12:40 - 13:00

A8: Olumuyiwa Otegbeye School of Mathematics, Statistics and Computer Science

Comparative Study Of Spectral-Based Numerical Methods For Solving Fluid Flow Problems

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Time T4 Lecture Theatre Title


14:00 - 14:20 A9: Njoku Chima .B. School of Chemistry and Physics

Effects Of Surfactants On The Solgel Synthesis Of Iro-Ce0.8Sm0.2O2-Δ Nanocomposite For Sofc Application.

14:20 - 14:40

A10: Khayelihle Xulu School of Mathematics, Statistics and Computer Science

Longitudinal Data Analysis In Electricity Consumption Using Mixed Models

14:40 - 15:00

A11: Vusi Mpendulo Magagula School of Mathematics, Statistics and Computer Science

Bivariate Spectral Collocation Based Quasilinearisation Method For Solving Non-Similar Boundary Layer Equations

15:00 - 15:20

A12: Simo Mthethwa School of Mathematics, Statistics and Computer Science

On Minimal Degrees Of Faithful Permutation Representations Of Finite Groups

ORAL PRESENATIONS (T5 Lecture Theatre)


Session 1 Chair: Prof Jules-Raymond Tapamo

09:50 - 10:10 B1: Andrew C. Eloka-Eboka School of Engineering

Engine Performance And Emission Characterization Of Biodiesel From Moringa And Jatroph Seeds Oils And Hybrids

10:10 - 10:30

B2: Nteseng Ramoraswi School of Chemistry and Physics

Photo-Catalytic Properties of Supported Tio2 Nanoparticles

10:30 - 10:50 B3: Lucy M. Ombaka School of Chemistry and Physics

Nitrogen-Doped Carbon Nanotubes As Supports For Pd Nanoparticle Catalysts

10:50 - 11:10 B4: Nomali Ngobese School of Engineering

Characterisation Of Potato Cultivars Recently Released In South Africa For Frozen French Fries

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11:40 - 12:00 B5: Matthew Lasich School of Engineering

Unlike Interactions In Simulated Methane Clathrate Hydrates

12:00 - 12:20 B6: Ray Leroy Khuboni School of Engineering

Threshold Segmentation Technique For Patch-Based Multi-View Stereo Algorithm

12:20 - 12:40 B7: Theodora Lamula School of Engineering

Adaptability And Adoptability Of Soil And Water Conservation Practices To Derive Best-Bet Options For Smallholder Farmers In Kwazulu-Natal

12:40 - 13:00 B8: Usiholo Iruansi School of Engineering

An Active Contour To Insulator Segmentation


14:00 - 14:20 B9: Meshack Sitati School Of Chemistry And Physics

The Role Of Ethylene Polyglycoxyl Pendant Units On The Terpy Based Platinum(Ii) Complexes. A Kinetic And Mechanistic Study.

14:20 - 14:40

B10: Olusula Bodede School Of Chemistry And Physics

Phytochemical and Biotechnological Studies of Zanthoxylum Capense: An Endangered South African Medicinal Species.

14:40 - 15:00

B11: Malekeng Sylvester Selala School Of Engineering

Development Of Models For Sustainable Rehabilitation Of Small-Scale Water Infrastructure (Swi): A Case Study In Makhudutamaga Local Municipality In The Limpopo Province

15:00 - 15:20 B12:Oyebode Kazeem School Of Engineering

Adaptive Parameter Selection For Graph Cut-Based Cells Segmentation

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Session 1 Chair: Prof Serban Proches

09:50 - 10:10 C1: Phumelele Kunene School of Agricultural, Earth and Environmental Sciences

Effects Of Socio-Economic Characteristics And Taste On Consumers’ Willingness To Pay For Organic Beef

10:10 - 10:30 C2: Oluwaseun A. Oyetade School of Chemistry and Physics

Effectiveness Of Cobalt Ferrite-Doped Carbon Nanotubes For The Adsorption Of Rhodamine B From Aqueous Solutions

10:30 - 10:50 C3: Awonke Mbangi School of Agricultural, Earth and Environmental Sciences

Soil Characterization And Plant Assesment For Phyto-Remediation Of Heavy Metals From Sewage Sludge Application

10:50 - 11:10 C4: Nhlanhla Shabalala School of Chemistry and Physics

Catalyst-Free Sonochemical Rapid Protocol For The Benign Methodology And Improved Synthesis Of Pyrazoles


11:40 - 12:00 C5: Masande Katamzi School of Agricultural, Earth and Environmental Sciences

In Sacco Degradation Properties And Inter-Relation Of Ten Roughages In Three Different Rumen Environments

12:00 - 12:20

C6: Stephanie Vivien Hayman School of Agricultural, Earth and Environmental Sciences

Use Of Foraminiferal Assemblages In Determining The Palaeoclimatic Record Of Two-Mile Reef, Sodwana Bay

12:20 - 12:40 C7: Elkhatab Abdalla School of Agricultural, Earth and Environmental Sciences

Grassland Management And Environmental Factors Effects On Soil Co2 Emission Under Smallholder Agriculture In Kwazulu-Natal Province

12:40 - 13:00 C12: Nyasha Chiuraise School of Agricultural, Earth and Environmental Sciences

Introgression Of Aflatoxin And Fumonisin Contamination Resistance Genes In Maize Hybridas

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Session 1 Chair: Dr Yogis Naidoo

09:50 - 10:10 D1: Siphelele Mafuleka School of Life Sciences

Modeling and Optimization of Xylose and Glucose Production from Napier Grass (Pennisetum Purpureum) using Hybrid Pretreatment Techniques

10:10 - 10:30 D2: Londiwe Magagula School of Life Sciences

Alternative Fodder Sources To Save Natural Grasslands: Increasing Napier Grass (Pennisetum Purpureum) Production With Bioslurry

10:30 - 10:50

D3: George Nyamato School of Chemistry and Physics

Unsymmetrical (Pyrazolylmethyl) Pyridine Metal Complexes As Catalysts For Ethylene Oligomerization Reactions: Role Of Solvent And Co-Catalyst In Product Distribution

10:50 - 11:10 D4: Chandika Ramlall School of Life Sciences

Effects Of Simulated Acid Rain On Germination And Subsequent Seedling Recruitment Of Trichilia Dregeana



14:00 - 14:20 C8: Macdex Mutema School of Agricultural, Earth and Environmental Sciences

Annual Water, Sediment, Nutrient And Organic Carbon Fluxes In River Basins: A Global Meta-Analysis As A Function Of Scale

14:20 - 14:40

C9: Humbelani Thenga School of Agricultural, Earth and Environmental Sciences

Runoff-Derived Carbon Dioxide Effluxes In A Sub-Tropical River Basin And Potential Controls

14:40 - 15:00

C10: Tendai Polite Chibarabada School of Agricultural, Earth and Environmental Sciences

Water Use Characteristics Of A Bambara Groundnut Landrace During Seedling Establishment

15:00 - 15:20

C11: Jean Nepomuscene Namugize School of Agricultural, Earth and Environmental Sciences

Effects Of Land Use And Land Cover Changes On Water Quality Of Umngeni River

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11:40 - 12:00 D5: Chika Chukwuma School of Life Sciences

Xylitol Reduces Intestinal Glucose Absorption Via Inhibiting Major Carbohydrate Digesting Enzymes, Slowing Gastric Emptying And Fastening Intestinal Transit Rate But Increases Muscle Glucose Uptake In Normal And Type 2 Diabetic Rats: A Multi-Mode Study

12:00 - 12:20 D6: Cassandra Naidoo School of Life Sciences

Comparison Of Oxidative State, Ultrastructure And Viability In Embryonic Axes Of Two Recalcitrant Seeded Species During Cryopreservation

12:20 - 12:40 D7: Lauren Eyssen School of Life Sciences

Recombinant Characterisation Of The Virulence Factor, Metacaspase 5, From T. Congolense

12:40 - 13:00 D8: Adriana Marais School of Chemistry and Physics

Quantum Effects In Photosynthesis


14:00 - 14:20 D9: Aminu Mohammed School of Life Sciences

Antidiabetic Effect Of Fruit Ethyl Acetate Fraction Of Aframomum Melegueta In A Type 2 Diabetes Rat Model

14:20 - 14:40 D10: Doty Okanda School of Life Sciences

Hyperlactatemia and Mtdna Polymerase Γ Gene Mutations in HIV Infected Zulu Patients on Stavudine-Based Art.

14:40 - 15:00 D11: Oluwole Samuel Aremu School of Chemistry and Physics

Novel Pyrimidine: Synthesis, Characterization And Their Anticancer Potential

15:00 - 15:20 D12: Kambaj Olivier Kambol School of Life Sciences

Environmental Determinants Of Species Composition And Distribution In Northern Coastal Forests In Kwazulu-Natal

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POSTER PRESENTATIONS

Poster Number Name Title of Poster

P1 Gbadebo Adeyinka School Of Chemistry And Physics

Evaluation Of Organochlorine Pesticides (Ocps) Residues In Sediment, And Water During Winter Season Of Msunduzi River, South Africa

P2 Perfect Chifoto School Of Chemistry And Physics

Mesosphere-Lower Thermosphere Planetary And Tidal Waves Structure Over Southern Hemisphere Using Hf Super Darn Hf Radar

P3 Chika F Nnadozie School Of Life Sciences

Identification And Functional Analysis Of Lignocellulose-Degrading Enzymes Genes From A Bacterial Metagenome From Eucalyptus Spp. Woodchips

P4 Sangeetha Venkataraman School Of Agricultural, Earth And Environmental Sciences

Studies on Applicability of Space-Borne Data for Addressing Air Pollution and its Health Impacts over South Africa

P5 Bongisiwe G.Shelembe School Of Chemistry And Physics

Phytochemical Comparison Of Two Indigenous Mistaken Medicinal Plants Of Kzn, Bridelia Micrantha And Sideroxylon Inerme And Their Antioxidant Activities

P6 Nomfundo Mahlangeni School Of Chemistry And Physics

Elemental Composition Of Cyrtanthus Obliquus And Lippia Javanica Used In South African Herbal Tonic, Imbiza

P7 Drushan Padayachee School Of Chemistry And Physics

Phase Transformation Of Iron In Hydroxyapatite In The Activation Of N-Octane

P8 Letrisha Padayachee School Of Life Sciences

Regulation Of The Thioredoxin System In Saccharomyces Cerevisiae

P9 Kimona Kisten School Of Chemistry And Physics

Elemental Distribution And Uptake By Watercress (Nasturtium Aquaticum) As A Function Of Water Quality

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P10 Feyisayo Odunitanwayas School Of Agricultural, Earth And Environmental Sciences

Fighting Hunger Beyond The Millennium Development Goals (Mdgs): Biofortified Provitamin A Maize To Enhance Chicken Nutritional Value For The Benefit Of Rural Households – A Review

P11 Fiona Maiyo School Of Life Sciences

Cytotoxicity Of Quercetin-3-O Glucoside And 4-(Β-D-Glucopyranosyl-1→4-Α-L-Rhamnopyranosyloxy)-Benzyl Isothiocyanate From Moringa Oleifera

P12 Toluwani Tella School Of Life Sciences

The Effect Of Psidium Guajava Aqueous Leaf Extract On Glycogen Synthase And Phosphorylase Enzymes In Liver Of Diabetic Rats

P13 Kudzai Mugadza School Of Chemistry And Physics

Effect Of Catalyst On Multiwalled Carbon Nanotube Quality Towards Application

P14 Jules Raymond Kala School Of Mathematics, Statistics And Computer Science

An Approximation Based Algorithm For Minimum Bounding Rectangle Computation

P15 Nada Abdelatif School Of Mathematics, Statistics And Computer Science

Modelling Of African Animal Trypanosomiasis Transmission In Kwazulu-Natal, South Africa

P16 Justina Okeke School Of Mathematics, Statistics And Computer Science

Double Reduction Of Conservation Laws Of Some Nonlinear Pdes In Fluid Dynamics.

P17 Beatrice Eagling School Of Life Sciences

Computational Modelling Of The Peroxiredoxin System Can Be Used To Distinguish The Kinetic Mechanism Of Hydrogen Peroxide Detoxification In Vitro

P18 Sharmini Pillay School Of Chemistry And Physics

Portable Qkd Device Using The Cow Protocol

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P19 Patrick Phepa School Of Mathematics, Statistics And Computer Science

Modelling The Transmission Dynamics Of Bovine Tuberculosis In Buffalo.

P20 Olumuyiwa Ogunlaja School Of Chemistry And Physics

Chemical Constituents Of Leaves And Stem Bark Of Uluzi (Ficus Burtt-Davyi)

P21 Moses Ollengo School Of Chemistry And Physics

An Investigation Of The Photostabilizing Potential Of Plant Extracts On Sunscreen Absorbers In Skin-Lightening Products

P22 Sithandiwe Khoza School Of Agricultural, Earth And Environmental Sciences

The Use Of Egg Powder In Improving The Food And Nutrition Security Of Rural Households Of Mkhambathini

P23 Khulani Kunene School Of Engineering

Direct Rolling Of Metal Powder Into Sheet Metal

P24 Makhamisa Senekane School Of Chemistry And Physics

A Quantum Walk-Based Mppt Optimization Algorithm For A Stand-Alone Pv System

P25 Kevin Garapo School Of Chemistry And Physics

Finite-Key Analysis Of The Pbc00 Protocol

P26 Seipati Mokhosi School Of Life Sciences

Characterisation Of Novel Galactosylated Liposomes For Liver-Targeted Gene Delivery

P27 Aloice Ogweno School Of Chemistry And Physics

(Pyridyl)Benzoazole Palladium (II) Complexes: Structure and Catalytic Hydrogenation of Alkenes and Alkynes

P28 Kerryn Houston School Of Life Sciences

The Glucocorticoid Receptor Is Silenced By Metyhlation In Small Cell Lung Cancer

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P29 Sithabile Hlahla School Of Agricultural, Earth And Environmental Sciences

The Vulnerability Of Tropical Fisheries To Climate Change: A Case Study Of Kapenta Fishery Of Lake Kariba, Zambia/Zimbabwe

P30 Adetoyese Adeyemo School Of Agricultural, Earth And Environmental Sciences

Ownership By Gender And Its Influence On Goats And Cattle Production Among The Isi-Tribe Of South Africa

P31 Sheldene Horne School Of Agricultural, Earth And Environmental Sciences

Cu, Fe, Mn & Zn Levels In Feeds, Forages, Stomach Contents And Livers Of Horses In South Africa

P32 Khanyisile Mdladla School Of Life Sciences

Population Structure And Breed Relations Of South African Indigenous Goat Ecotype Populations Using Genomewide Snp Data

P33 Siphiwo Mtshali School Of Mathematics, Statistics And Computer Science

Using Economic And Mathematical Epidemiology In Infectious Diseases Intervention Modeling: Focusing On Hiv Model Incorporating Serodiscordant Couples

P34 Hazmatally Goolam Hossen School Of Chemistry And Physics

Quantum Self-Avoiding Walks

P35 Thembisile Zaca School Of Chemistry And Physics

Pyridinyl(Benzoazole) Cu(Ii) And Zn(Ii) Metal Complexes: Synthesis And Application As A Catalyst In Polymerization Of Lactides And Ԑ-Carpolactones

P36 Ayanda Zungu School Of Chemistry And Physics

Studying The Evolution Of Cold Gas In Galaxies: Large Absorption Line Survey With Meerkat

P37 Murtala Isah Bindawa School Of Life Sciences

Effects Of Oleanolic Acid On Small Intestine Morphology And Enzymes Of Glutamine Metabolism In Diabetic Rats

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P38 Depika Dwarka School Of Life Sciences

Critical Overview Of Sem Preparation Techniques For Seed Arils From Strelitzia Nicolai

P39 Kabwit Alain Ntambwe School Of Engineering

Experimental Investigation Of Aeolian-Vibrational Loads On Composite Insulators

P40 Zandile Mngadi School Of Agricultural, Earth And Environmental Sciences

Integrated Control Of Fusarium Head Blight Of Wheat

P41 Mirara Simon School Of Engineering

Characterization And Processing Of Faecal Sludge In The Lab Scale Ladepa Machine

P42 Nhlakanipho Kwazi Mthembu

School Of Chemistry And Physics

Dynamical Mass Estimates Of Sunyaev-Zel'dovich Effect Selected Galaxy Clusters In The Millennium Gas Simulations

P43 Shirveen Sewpersad School Of Chemistry And Physics

The Levels Of Selected Metals And Pahs In Lake Mzingazi And Qubhu Lake

P44 Ovokeroye Abafe School Of Chemistry And Physics

Development Of An In Vitro Human Gastrointestinal Tract For The Determination Of Oral Bioaccessibility Of Polybrominated Diphenyl Ethers In Contaminated E-Waste Sites

P45 Nombuso Majola School Of Chemistry And Physics

Digital Control Of Light

P46 Albert Muzhingi School Of Engineering

Forward Osmosis Of Urine

P47 Nolubabalo Ndaliso School Of Life Sciences

Modelling Of Hydrogen Production From Synthetic Wastewater As A Function Of Hydraulic Retention Time And Organic Substrate Concentration

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P48 Masoko Malesa School Of Life Sciences

Runs Of Homozygosity In Swakara Sheep

P49 Lerato Mollo School Of Chemistry And Physics

Photochemical Synthesis Of Lamivudine Derivatives

P50 Onkabetse Sengate School Of Chemistry And Physics

Using Jvla To Remove Cmb Forerounds

P51 Rasheed Adebayo School Of Agricultural, Earth And Environmental Sciences

Can Rumen Fill Be Predicted Using Artificial Neural Network?

P52 Tyrone Naidoo School Of Engineering Improving Network Intrusion Detection Using Honeypot

Sensors And Data Mining Techniques

P53 Chrisanne Naicker School Of Chemistry And Physics

Identification And Quantification Of Chelidonic Acid And Other Ligands With Potential For Ni Uptake In The Hyperaccumulator, Berkheya Coddii

P54 Eunice Nyawade School Of Chemistry And Physics

Antimicrobial Activity Of New Ruthenium(Ii) Amine Complex Salts, [(Η5-C5h5)Ru(Co)2l]Bf4 (L = Rnh2)

P55 Caroline Okoth School Of Life Science

Suitability Of Selected Methods For Rearing Cotesia Sesamiae Cameron (Hymenoptera: Braconidae) And Effect Of Odour On Host Acceptance

P56 Elphas Luchemo School Of Mathematics, Statistics And Computer Science

Risk Factors And Spatial Variation Of Herpes Simplex-2 Virus In Kenya

P57 Oluwakorede Oluyide School Of Mathematics, Statistics And Computer Science

Automatic Lung Segmentation Using Graph Cut Optimization

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P58 Maombi D. Mkenyeleye School Of Mathematics, Statistics And Computer Science

Gravitational Collapse of Generalized Vaidya Spacetime

P59 Olaoluwa Olarewaju School Of Agricultural, Earth And Environmental Sciences

Prediction Of Mesocarp Moisture Content, Dry Matter And Mesocarp Oil Of ‘Hass’ Avocado Using Nirs

P60 Reyna Singh School Of Engineering

Reactor Model And Catalyst Performance Data Evaluation In The 2-Stage Direct Coal Liquefaction Process

P61 Sylvester Werekeh Fomum

School Of Agricultural, Earth And Environmental Sciences

Foraging Efficiency Of Nguni Goats In Relation To Plant Species And Seasons In An Arid Sub-Tropical Savannah, South Africa

P62 Owen Daniel Pandaram School Of Chemistry And Physics

Theoretical And Computer Simulation Study Of Phase Coexistence In Binary 2d-3d Hard Core Mixtures

P63 Mashamaite Lefentse School Of Life Science

Determining The Mechanism Of Action For Deglutathionylation By The Glutathione/Glutaredoxin (Gsh/Grx) System Using Computational And Mathematical Models.

P64 Hannah Adebanjo School Of Engineering

Covariance Clustering For Dimensionality Reduction In Hyperspectral Images

P65 Catherine Wiid School Of Agricultural, Earth And Environmental Sciences

Linking Ulceration And Discolouration Of The Equine Gastro-Intestinal Tract To Diet

P66 Humairah Bassa School Of Chemistry And Physics

State And Parameter Estimation Using The Hybrid Formalism

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P67 Vongai Murugani School Of Agricultural, Earth And Environmental Sciences

Women Empowerment In Agriculture Index - Are Female Smallholder Irrigation Farmers In Rural Limpopo Province Empowered?

P68

Samuel Kusangaya School of Agriculture, Earth and Environmental Sciences

Understanding Uncertainty In Rainfall From Regional Climate Model Simulations: A Hydrological Perspective

P69 Nhlakanipho Kwazi Mthembu

School of Mathematics, Statistics and Computer Science

Dynamical mass estimates of Sunyaev-Zel'dovich effect selected galaxy clusters in the Millennium Gas simulations

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ORAL ABSTRACTS

A1

ANALYSIS OF VIROTHERAPY IN SOLID TUMOR INVASION

Joseph Malinzi

[email protected] School of Mathematics, Statistics, and Computer Science

Supervised by Prof Precious Sibanda and Dr Hermane Mambilimamboundou

Cancer treatment is still a mystery despite traditional cancer therapies. The traditional cancer treatments have high levels of toxicity and relatively low efficacy. Current research and clinical trials have indicated that virotherapy, a procedure which uses replication-competent viruses to kill cancer cells, has less toxicity and a high efficacy. However, the interaction dynamics of the tumor host, the virus, and the immune response is poorly understood due to its complexity. We present a mathematical analysis of models that study tumor-immune-virus interactions in the form of differential equations with spatial effects. A stability analysis is presented and we obtained analytical traveling wave solutions. Numerical simulations were obtained using fourth order Runge-Kutta and Crank-Nicholson methods. We show that the use of viruses as a cancer treatment can reduce the tumor cell concentration to a very low cancer dormant steady state or possibly deplete all tumor cells in body tissue. The traveling waves indicated an exponential increase and decrease in the cytotoxic-T-lymphocytes (CTLs) density and tumor load in the long term respectively.

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A2

QUANTUM MACHINE LEARNING AND ITS APPLICATION IN DATA MINING

Maria Schuld [email protected]

School of Chemistry & Physics Supervised by Prof Francesco Petruccione

Quantum machine learning is a combination of quantum information theory and machine learning, exploring ways to solve problems of intelligent data mining on a hypothetical quantum computer. The goal is to exploit the powerful features of parallel information processing through quantum systems in order to improve the scope and efficiency of classical machine learning algorithms. Innovations in intelligent computing are thereby of crucial importance for future technologies that deal with the growing amounts of data produced and stored in our information society. We want to introduce into the challenges and promises of quantum machine learning research and present our current work on quantum pattern recognition tasks.

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A3

ON THE EXISTENCE OF SELF-DUAL CODES INVARIANT UNDER PERMUTATION GROUPS

Tendai. M. Mudziiri Shumba [email protected]

School of Mathematics, Statistics and Computer Science Supervised by Professor Bernardo Rodrigues, Professor Simon Mukwembi

Let G be a prescribed permutation group. We study the question of existence of self-dual codes over a field F=Fq, q=pl, p a prime, admitting G, that is, are G-invariant. This depends on the structure of G and its representations as well as the base field Fq. We investigate what conditions are necessary and sufficient for the existence of such codes. Representation theoretic as well as group theoretic methods are used. For the binary case we look at the existence of self-dual binary codes of length n which are invariant under the symmetric groups Sn and the alternating groups An,n≥ 4. We find that such codes do not exist. Further, for the sporadic simple and almost simple groups of degree ≤ 2000, M11, M12 , M22, M23, M24, J1, J2,HS, Co3, M12:2, M22:2 and J2:2 we search for G-invariant self-dual codes of various lengths and attempt a classification where computations were possible, or theoretical methods permitted.

27

A4

ROBUST DETECTION OF VESSELS IN RETINAL IMAGES USING DIFFERENCE IMAGE AND K-MEANS CLUSTERING TECHNIQUE

Temitope Mapayi [email protected]

School of Mathematics, Statistics & Computer Science Supervised by Prof. Serestina Viriri & Prof. Jules-Raymond Tapamo

Digital retinal photography, and image analysis in ophthalmology have been lately identified to be helpful in the diagnosis and progress monitoring of several diseases like diabetic retinopathy (DR), retinopathy of prematurity (ROP) and cardiovascular diseases [2]. As DR and ROP continues to be major causes of visual loss and blindness worldwide [1], early detection and management of these diseases will help achieve significant reduction of blindness cases [1], [4]. Ophthalmologists, with the help of detected vessel network, concentrate on retinal vessel feature analysis during the diagnosis of the diseases. Manual detection and analysis of the retinal vessels in the fundus images has been a very tedious and time consuming task that requires trained and skilled personnel who are often scarce [3]. However, with the help of automatic vasculature segmentation and analysis, ophthalmologist can now diagnose and efficiently manage the diseases [2]. Although, much has been achieved in the literatures on the automatic segmentation of retinal vessels, the segmentation of some large and thinner vessels in retinal images as well as the reduction of false detection around the border of the optic disc are still unresolved. This research work presents an investigatory study on the combination of difference image based on low pass filter and K-means clustering for robust retinal vessel network segmentation. This research work shows that K-means combined with difference image based on median filter out-performs difference image based on mean filter as well as difference image based on Gaussian filter while combined with K-means for retinal vessel network segmentation. The good performance of the difference image based on median filter is however attributed to the good edge-preserving property of median filtering technique. A maximum average accuracy of 0.9556 and a maximum average sensitivity of 0.7581 were achieved on DRIVE database. While compared with the previously used techniques on DRIVE database, the proposed technique yields higher average sensitivity and average accuracy rates in the same range of very good specificity. REFERENCES [1] Gergely K., and Gerinec A.: Retinopathy of prematurity epidemics, incidence, prevalence, blindness. Bratislavske lekarske listy, 111(9):514-517, 2009. [2] Klonoff D. C., Schwartz D. M.: An economic analysis of interventions for diabetes. Diabetes Care, 23(3), 390-404, 2000. [3] Varughese S., Gilbert C., Pieper C., and Cook C.: Retinopathy of prematurity in South Africa: an assessment of needs, resources and requirements for screening programmes. British Journal of Ophthalmology, 92(7):879- 882, 2008. [4] Zhang, Z., Srivastava, R., Liu, H., Chen, X., Duan, L., Wong, D. W. K., ... & Liu, J. : A survey on computer aided diagnosis for ocular diseases. BMC medical informatics and decision making, 14(1), 80, 2014.

28

A5

REAL SPACE LENSING RECONSTRUCTION USING CMB TEMPERATURE AND POLARISATION

Heather Prince [email protected]

School of Mathematics, Statistics and Computer Science Supervised by Prof Kavilan Moodley

Gravitational lensing of the cosmic microwave background (CMB) probes the distribution of matter in our universe, of which dark matter forms a dominant part. It also allows us to delens the CMB and obtain an accurate picture of its primordial fluctuations. We explore methods of reconstructing the lensing field from the lensed CMB temperature and polarisation in real space, as an alternative to the harmonic space estimators currently in use. Real space estimators have the advantage of being local in nature and they are thus equipped to deal with the nonuniform sky coverage, galactic cuts and point source excisions found in experimental data. These estimators can be applied to CMB temperature and polarisation maps to reconstruct the lensing convergence and shear, which are directly related to the matter distribution.

29

A6

BAYESIAN FRAILTY MODELING USING THE INTEGRATED NESTED LAPLACE: AN APPLICATION TO UNDER-FIVE CHILD MORTALITY IN

UGANDA.

Justine, Nasejje [email protected]

School of Mathematics, Statistics and Computer science. Supervised by Prof. Henry Mwambi and Dr. Thomas Achia.

Infant and child mortality rates are among the health indicators of importance in a given community or country. It is the fourth millennium development goal that by 2015, all the United Nations member countries are expected to have reduced their infant and child mortality rates by two-thirds. Uganda is one of those countries in sub-Saharan Africa with high infant and child mortality rates and therefore it is important to find out the factors strongly associated to these high rates in order to inform the design of appropriate intervention strategies to reduce the existing high infant and child mortality rates. The Uganda Demographic Health Survey (UDHS) funded by USAID, UNFPA, UNICEF, Irish Aid and the United Kingdom government provides a data set which is rich in information. Survival analysis techniques are among the well-developed methods in Statistics for analyzing time to event data. These methods were adopted in this paper to examine factors affecting under-five mortality in Uganda using the UDHS data for 2011 using R and STATA software. Results obtained by fitting the Cox-proportional hazard model and frailty models and drawing inference using the Frequents approach at 5% significance level, there was evidence of the existence of unobserved heterogeneity at household level but there was not enough evidence to conclude the existence of unobserved heterogeneity at community level. Other factors like sex of the household head, sex of the child and number of births in the past one year were found to be significant. Conclusion Demographic factors (sex of the household head) and Biological determinants (sex of the child and number of births in the past one year) are strongly associated with high under-five child mortality rates. Heterogeneity or unobserved covariates were found to be significant at household but insignificant at community level.

30

A7

MULTIPLE CONTROL STRATEGIES INTERVENTION ON HIV INFECTION

Komi Afassinou, [email protected]

School of mathematics, Statistics, and Computer Science Supervisors: Dr. Chirove Faraimunashe, Prof Kesh Govinder

We developed an HIV/AIDS model which sought to assess the impact of a multiple control strategies including pre-exposure prophylaxis (PrEP) use awareness and PrEP efficacy, as preventative interventions, and the use of anti-retroviral drugs (ARVs) as post-infection intervention. The model analysis is carried out to establish the threshold conditions that determine the stability of the steady states. Further, through sensitivity analysis theory, we examine the different social factors parameterized that likely induce the spread of HIV infection. Next we investigate the optimal strategic ways of implementing an effective intervention schedule through optimal control theory. Numerical simulations were carried out to gain insight regarding the use and the efficacy of PrEP as well as the use of ARVs by considering different possible interventions.

\

31

A8

COMPARATIVE STUDY OF SPECTRAL-BASED NUMERICAL METHODS FOR SOLVING FLUID FLOW PROBLEMS

Olumuyiwa Otegbeye [email protected]

School of Mathematics, Statistics and Computer Science Supervised by Prof. Sandile S. Motsa

In this presentation, a comparative study is carried out on three spectral based numerical methods which are the spectral quasilinearization method (SQLM), the spectral relaxation method (SRM) and the spectral local linearization method (SLLM). The study is carried out by using the numerical methods to solve a system of partial differential equations modeling the unsteady three-dimensional MHD boundary layer flow and heat transfer over an impulsively stretching plate. Residual error analysis is used in determining the speed of convergence, convergence rate and accuracy of the methods. The performance of the methods are measured in terms of convergence, accuracy and rate of convergence. The ease of development and implementation of the associated numerical algorithms are also considered.

32

A9

EFFECTS OF SURFACTANTS ON THE SOLGEL SYNTHESIS OF IrO-

Ce0.8Sm0.2O2-δNANOCOMPOSITE FOR SOFC APPLICATION.

Njoku Chima .B. [email protected]

School of chemistry and physics, University of KwaZulu-Natal, Westville campus, Durban, South Africa.

Supervised by Dr. Patrick Ndungu

The sol-gel technique is a versatile and relatively simple method, easily adapted to synthesize complex metal oxide formulations. The sol-gel technique takes advantage of the structural directing properties and templating characteristics of non-ionic, anionic and cationic surfactant to produce porous Iridium oxide, with Samarium doped Ceria (SDC) nanoparticles. The nano-powders were calcined at a temperature of 950 °C and the crystalline nano- structures and compositions were characterized by high resolution transmission electron microscopy and X-ray diffraction. Textural characteristics and particle morphology were respectively characterized by Nitrogen sorption at 77.5 K and scanning electron microscopy respectively. The electrochemical properties were characterised by using kittec squadro, Solid Oxide Fuel Cell testing equipment, with air and hydrogen as the gases used. The nature of the surfactant influenced particle morphology, pore diameter, pore size, Crystallite size, surface area and electrochemical properties.

33

A10

LONGITUDINAL DATA ANALYSIS IN ELECTRICITY CONSUMPTION USING MIXED MODELS

Khayelihle Xulu [email protected]

School of Mathematics, Statistics and Computer Science Supervised by Prof. Temesgen Zewotir

Modelling longitudinal data in electricity consumption of KwaMashu residential area in eThekwini Municipality from 2 January 2008 to 9 July 2013, using the mixed models. EThekwini Electricity unit purchases just over 5% of the total energy generated by Eskom, transforms and redistributes this power to the municipality’s business customers and their residential area customers. This study aims to provide descriptive information on electricity consumption and investigates the effects which has played a significant role in the estimation of electricity consumption and causes it to vary from month to month and season to season, this can be geysers and space heaters working harder during the winter months, air conditioning units working harder during the summer months, a change in the number of people living at the premises, etc. As electricity is important for social and economic development in South Africa, this study serves as the reference materials for the municipality in developing its electricity conservation policy and determining the electricity supply strategic plans.

34

A11

BIVARIATE SPECTRAL COLLOCATION BASED QUASILINEARISATION METHOD FOR SOLVING NON-SIMILAR BOUNDARY LAYER EQUATIONS

Vusi Mpendulo Magagula [email protected]

School of Mathematics, Statistics and Computer Science Supervised by Prof. S. Motsa, Prof. P. Sibanda

In this study, a method for solving non-similar boundary layer equations is presented. The method uses the concept of quasilinearisation, and combines it with the Chebyshev spectral collocation method on approximate functions defined as bivariate Lagrange interpolation. We demonstrate for the first time, the application of the method by solving nonlinear system of partial differential equations that belong to a class of non-similar boundary layer equations. The model equations considered describe the problem of magnetohydrodynamic forced convection flow adjacent to a non-isothermal wedge. Residual error analysis, convergence analysis and grid independence tests are conducted to establish the accuracy, convergence and validity of the proposed method. The results from the present work are also validated against results from published literature. The proposed method is better than existing methods for solving a class of non-similar boundary layer equations since it converges faster and uses few grid points to achieve accurate results. The proposed method uses minimal computation time and its accuracy does not deteriorate rapidly with increase in time. The solution procedure of the proposed method is easy to develop since everything is based on well-established formulas.

35

A12

ON MINIMAL DEGREES OF FAITHFUL PERMUTATION REPRESENTATIONS OF FINITE GROUPS

Simo Mthethwa

[email protected] School of Mathematics, Statistics and Computer Science

Supervised by Prof Bernardo Rodrigues

The minimal faithful degree of a finite group G, denoted by µ (G), is the smallest non-negative integer n; such that G is isomorphic to a subgroup of Sn, the symmetric group on n symbols. We study the minimal faithful degrees of certain classes of finite groups and the additivity property of µ in relation to a direct product of finite groups. Concrete examples will be provided on how to calculate µ (G), for various classes of finite groups. It is not difficult to show that if H is a subgroup of G, then µ (H) ≤ µ (G). However, if N is a normal subgroup of G, it is possible to have µ (G/N) > µ (G). If the latter holds, we call G an exceptional group, N and G/N are called distinguished subgroup and distinguished quotient, respectively. We investigate the extent to which certain classes of groups satisfy the exceptionality property. In the particular case of p-groups (i.e., groups of order p^n, where p is prime and n is a positive integer), for p^5, we provide examples of exceptional and non-exceptional p-groups. Conditions under which a quotient group of a finite group is distinguished will also be explored.

36

B1

ENGINE PERFORMANCE AND EMISSION CHARACTERIZATION OF BIODIESEL FROM MORINGA AND JATROPH SEEDS OILS AND HYBRIDS

Andrew C. Eloka-Eboka [email protected]

School of Engineering Supervised by Dr Freddie Inambao Biodiesel fuels are one of the easiest alternative fuels to be utilized in the compression ignition engines. They are renewable, environmentally friendly and produce less gaseous and exhaust emissions. A variety of biodiesel feedstocks have been experimented using different engine types and for various performance evaluations. In this study, overall engine performance tests and gaseous/emission characterizations were conducted in a four stokes versatile internal combustion engine (TD 300) over a wide range of throttle from the feedstocks of Moringa and Jatropha biodiesel and their resultant biodiesel hybrids. The hybrid compositions were J50M50, J40M10, J30M20, J20M30, and J10M40 from crude oil samples (in situ) and: BM50J50, BM40J10, BM30J20, BM20J30 and BM10J40 from produced biodiesel (ex situ). The biodiesel were produced by transesterification at specific optimization protocols and subjected to a novel approach in biodiesel development, hybridization using in situ and ex situ processes as reported in earlier studies of Eloka-Eboka and Inambao, [1]. The single stock biodiesel of Moringa and Jatropha and their hybrids performed favourable in comparison with the AGO following ASTM standardized procedures. The torque, air consumption, ambient air temperature and pressure, specific fuel consumption, brake thermal and mechanical efficiency, brake power, engine noise, exhaust temperature and smoke opacity were determined with significant difference; gaseous emission was conducted using an online sampler which was subjected to a GC-MS spectrophotometer interacting with a flame induced detector (FID) for all comparisons. Results show greater improvement in performance from the hybrids and Moringa biodiesel with close similarity with AGO. The emissions were however insignificant to the immediate environment as against those of AGO. Biodiesel development continues to be a current research until the much needed breakthrough is achieved the world over. REFERENCES [1] Eloka-Eboka, A.C. and Inambao, F.L. (2014). Hybridisation of feedstocks - a new approach in biodiesel development: A case of Moringa and Jatropha seed oils. Energy Sources Part A (Taylor and Francis) (Accepted and in Press).

37

B2

PHOTO-CATALYTIC PROPERTIES OF SUPPORTED TiO2 NANOPARTICLES

Nteseng Ramoraswi [email protected]

School of Chemistry and Physics Supervised by Dr Patrick Ndungu

Multi-walled carbon nanotubes were coated with mesoporous silica (SBA 15). A modified sol gel method was then employed to disperse titania nano-particles onto the silica/CNT nano-composite. The physical-chemical properties of the nano-composites, with and without titania, were thoroughly characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM), nitrogen sorption at 77 K, X-ray diffraction (XRD), Raman spectroscopy, FTIR and UV-Vis diffuse reflectance spectroscopy. The results revealed that the well graphitic CNTs were uniformly coated with SBA-15 at 30 wt% loading, and surface area and pore volume increased with the silica loading. From the HRTEM observations, the titania nano-particles were well dispersed on the composites, and the titania was in the photo-active anatase phase. The photo-catalytic properties were probed using a model organic pollutant, methylene blue. Photo-catalytic efficiency of TiO2 catalyst is highly influenced by the physical and chemical properties on the material.

38

B3

NITROGEN-DOPED CARBON NANOTUBES AS SUPPORTS FOR Pd NANOPARTICLE CATALYSTS

Lucy M. Ombaka, E-mail: [email protected]

School of Chemistry and Physics Supervised by: Dr. Patrick G. Ndungu and Dr.Vincent O. Nyamori

Catalytic reactions uphold the principles of green chemistry by increasing the efficiency of producing chemicals in industries. It is therefore necessary to develop sustainable and selective catalytic systems that optimize the synthesis of industrial chemicals. To accomplish this, an efficient metal catalyst system with a high surface-to-volume ratio, a high degree of particle dispersion and good metal-support interactions, among other properties, is necessary [1]. Nitrogen doped carbon nanotubes (N-CNTs) are carbonaceous materials exhibiting the afore-mentioned properties, making them attractive materials for use as metal catalyst supports [2]. Pd catalysts supported on N-CNTs is postulated to show high catalytic activity in diverse reactions. In this study, we aimed at synthesizing N-CNTs and applying them as supports for Pd nanoparticle catalysts. Aligned nitrogen-doped carbon nanotubes (N-CNTs) containing 4.4% of nitrogen were synthesized using chemical vapour deposition (CVD) method and used as supports for Pd nanoparticles. The catalysts were characterized using transmission electron microscopy (TEM), scanning transmission electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA) and Raman spectroscopy. The presence on nitrogen in CNTs was evaluated using XPS analysis, which revealed a nitrogen content of 2.5-4.5%. The N-CNTs were purified via acid treatment and Pd nanoparticles were supported on them. Scanning TEM (STEM) and regular TEM were used to visualize the Pd nanoparticles supported on N-CNTs (Fig. 1).

Figure 1. TEM image of Pd supported on N-CNTs; note the Pd is on the defect sites

From the STEM and TEM images, it was evident that Pd nanoparticles were mainly located along the defect sites of N-CNTs. This implied that the defect sites consisted of electron rich functional groups which enhanced the electronic interaction between Pd nanoparticles and N-CNTs. REFERENCES [1] L. M. Ombaka, P. Ndungu and V. O. Nyamori, Catal. Today, 2013, 217, 65-75. [2] K. Chizari, I. Janowska, M. Houllé, I. Florea, O. Ersen, T. Romero, P. Bernhardt, M. J. Ledoux and C. Pham-Huu, Appl. Catal. A: General, 2010, 380, 72-80.

Pd nanoparticle

39

B4

CHARACTERISATION OF POTATO CULTIVARS RECENTLY RELEASED IN SOUTH AFRICA FOR FROZEN FRENCH FRIES

Nomali Ngobese

[email protected] School of Engineering

Supervised by Professor Tilahun Workneh The consumption of frozen French fries is increasing in South Africa, due to the growing appeal of the product to consumers as a convenience food. However, only few potato cultivars are used by the frozen French fry industry, as few South African cultivars are suitable for processing. A review of the literature pertaining to the selection of potato cultivars suitable for processing was done, to determine the industry requirements for producing standard quality frozen French fries. In addition, the pre- and post-harvest factors affecting the quality of frozen French fries were reviewed, with the aim of collecting information to design a project focusing on increasing the quantity of fresh potatoes available for consideration to processors in the country. The review indicated that tuber solids, mainly evaluated by assessing the specific gravity and reducing sugar content, morphology and the occurrence of physiological defects are the main characteristics considered when selecting fresh potatoes for processing. Potatoes of high specific gravity and low reducing sugar content are targeted as these properties influence the colour, texture and oiliness of French fries, which are important characteristics affecting the acceptability of fries by consumers. Selection of potato tubers used for French fry production is done on a cultivar basis, mainly because genotype is the main factor determining the development of these characteristics. Secondly, agro-climatic and agronomic practices experienced by the crop during cultivation influence the development of these characteristics and determine yields at harvest. Subsequently, tuber maturity, post-harvest handling practices, storage conditions and processing operations affect the quality of tubers and frozen French fries produced. Processors prefer high-yielding cultivars, with minimal defects, as they result in limited losses during processing and ensure high product yields. High oil and acrylamide contents are the main concerns associated with French fry consumption, which should be regulated by selecting suitable verities and thereafter optimising the processing conditions for achieving a quality product. A research project was therefore proposed, to characterise potato cultivars recently released in South Africa for frozen French fries, by assessing the agronomic performance of cultivars under typical cultivation practices, to determine those suitable for processing, and determining optimum processing treatments for suitable cultivars, to produce quality frozen French fries.

40

B5

UNLIKE INTERACTIONS IN SIMULATED METHANE CLATHRATE HYDRATES

Matthew Lasich [email protected]

School of Engineering Supervised by Prof. Amir H. Mohammadi (UKZN), Prof. Kim Bolton (Borås), Prof. Jadran

Vrabec (Paderborn), and Prof. Deresh Ramjugernath (UKZN) Clathrate hydrates are a naturally-occurring ice-like substance consisting of a network of hydrogen-bonded water molecules surrounding and ‘trapping’ gas molecules [1]. In the case of natural gas clathrate hydrates, this gas is chiefly methane. Deposits of methane clathrate hydrates can be found in the deep ocean and in permafrost in tundra regions [1]. At present, they are of interest in the field of flow assurance [2], where they form blockages in undersea pipelines. This contribution examines the effect of altering the unlike intermolecular interactions on thermophysical property predictions for methane clathrate hydrates, through the use of atomistic molecular calculations. Knowledge of the thermodynamic stability of clathrate hydrates can assist in reducing the costs of offshore natural gas exploitation. The present study consisted of three separate investigations. The applicability of lattice distortion theory [3] to determine unlike intermolecular interactions by fitting to experimental data was considered [4]. Next, the effect of unlike intermolecular interactions on fitted adsorption isotherms, and calculated phase equilibria was investigated [5], although the use of simulated adsorption isotherms to predict phase equilibria had to be demonstrated first [6]. Several conclusions were drawn from these investigations which were of practical interest. Firstly, lattice distortion theory cannot produce fits to all desired properties, and is too sensitive to render is practically useful. Secondly, phase equilibria can be predicted quite accurately using simulated adsorption isotherms. Lastly, adjusting unlike intermolecular interactions in adsorption simulations can result in more accurate phase equilibrium predictions, although an exact fit may not be possible due to the solution space of the problem at hand. REFERENCES [1] E.D. Sloan, C.A. Koh, Clathrate Hydrates of Natural Gases, CRC Press, Boca Raton, 2008. [2] E.G. Hammerschmidt, Ind. Eng. Chem. 26 (1934) 851-855. [3] S.R. Zele, S.-Y. Lee, G.D. Holder, J. Phys. Chem. B 103 (1999) 10250-10257. [4] M. Lasich, A.H. Mohammadi, K. Bolton, J. Vrabec, D. Ramjugernath, Phil. Mag. 94 (2014) 974-990. [5] M. Lasich, A.H. Mohammadi, K. Bolton, J. Vrabec, D. Ramjugernath, Fluid Phase Equilibria 381 (2014) 108-115. [6] M. Lasich, A.H. Mohammadi, K. Bolton, J. Vrabec, D. Ramjugernath, Fluid Phase Equilibria 369 (2014) 47-54.

41

B6

THRESHOLD SEGMENTATION TECHNIQUE FOR PATCH-BASED MULTI-VIEW STEREO ALGORITHM

Ray Leroy Khuboni

[email protected] School of Electronic, Electrical and Computer Engineering

Supervised by Mr Bashan Naidoo

This research is based on the state-of-the-art Multi-View Stereo (MVS) reconstruction algorithms. There are many MVS algorithms that are able to reconstruct accurate 3D models from a set of 2D images of real world objects or scenes. However, most algorithms are limited and only the best MVS algorithms are able to achieve results that rival 3D laser scanners. Laser scanners are an active scanning system that render 3D models by analyzing the distortion of structured light (laser beams) that is projected onto the surface of an object. The methodology is costly and invasive. Image-based modeling is a passive, low-cost alternative with minimal hardware complexity. 3D modeling can be achieved by processing ordinary 2D images of any rigid 3D object. It is also possible under certain circumstances to use the MVS technique to model deformable objects and objects in motion. A recent study shows a comparison and evaluation of different MVS algorithms [1], and it identifies the Patch-based MVS algorithm by Y. Furukawa and J. Ponce [2] as the best performing algorithm. This algorithm is able to handle all types of image dataset such as objects, scenes and crowded scenes and proves to be efficient at producing very accurate 3D models but lacks computational efficiency. In this research, we investigate the use of an adaptive segmentation technique to pre-process the input to the Patch-based Multi-View Stereo (PMVS) algorithm. An adaptive threshold technique segments objects of interest from disruptive background data. By using segmented images along with the PMVS algorithm, we are able to reduce the cumulative error in the reconstruction process and thus improve the final reconstruction. Performance evaluation of the reconstruction algorithm with segmented data shows simultaneous reduction in computational times and improvements to specific reconstruction challenges. With this method, we obtain results that are generally similar to the original with reduced time and space complexity. REFERENCES [1] S. M. Seitz, B. Curless, J. Diebel, D. Scharstein, and R. Szeliski, “A comparison and evaluation of multi-view stereo reconstruction algorithms,” in Proceedings of the 2006 IEEE Computer Society Conference on Computer Vision and Pattern Recognition - Volume 1, CVPR ’06, (Washington, DC, USA), pp. 519–528, IEEE Computer Society, 2006. [2] Y. Furukawa and J. Ponce, “Accurate, dense, and robust multi-view stereopsis,” IEEE Transactions on Pattern Analysis and Machine Intelligence, vol. 32, no. 8, pp. 1362–1376, 2010.

42

B7

ADAPTABILITY AND ADOPTABILITY OF SOIL AND WATER CONSERVATION PRACTICES TO DERIVE BEST-BET OPTIONS FOR SMALLHOLDER FARMERS

IN KWAZULU-NATAL

Theodora Lamula [email protected],

School of Engineering Supervised by: Dr A Senzanje and Dr M Mudhara

There is a need for agricultural production methods to incorporate Soil and Water Conservation (SWC) techniques in order to increase water use efficiencies and soil fertility to facilitate crop growth for improved food security in rural South Africa. In a quest to maximise crop production, SWC techniques have been promoted to smallholder farmers. This study looks at the dynamics that entail the adoption and adaptation of SWC practices by smallholder farmers, by assessing the factors that are affecting the adaptation and adoption of different SWC practices. The study was undertaken in Bergville, which is under the Okhahlamba District Municipality in the province of KwaZulu-Natal. A sample of 300 farmers was drawn randomly from 13 villages where farmers were interviewed from their plots using a structured questionnaire. The assessment was done by first identifying five SWC practices currently used by the farmers, determining the adoption and adaptation of the SWC practices and deriving the best-bet options from the practices that fit the socio-economic conditions of the farmers. The best-bet options were determined through the multi-attribute decision making (MADM) method. The identified practices were minimum tillage, crop rotations, mulching, intercropping and garden beds. To analyse the adoption and adaptation of the different practices, descriptive statistics and t-tests for comparison of means were used. The dependent variables results showed the number of households who adopted the practices to be at 55% for intercropping, 36% for minimum tillage), 32% for crop rotations, 24% for mulching and 18% for garden beds. The descriptive analysis also showed that only 15% of the farmers have off farm employment, 13% used credit for farming and only 14% of the farmers had access to credit. Using the Logit regression model it was found that variables like membership of a farmer support group (p=0.053), the use of credit (p=0.016), how the fertilizer is applied (p=0.002), the condition of the soil (p=0.000), the support of a government extension officer (p=0.001) and off farm employment (p=0.021) were significant variables that determined adoption of the SWC practices. The divisibility (p=0.076), profitability (p=0.070) and trialability (p=0.087) of the individual practices were found to be the determinants in the adaptation of the practices. The results obtained from both regressions were used to derive the best-bet options. A model indicating the pathway to attain the best-bet options was developed to serve as recommendations that will assist the smallholder farmers. This study shed light on the constraints that face smallholder farmers in adapting and adopting SWC practices in South Africa, where little has been done to study the adoption and adaptation of SWC techniques.

43

B8

AN ACTIVE CONTOUR TO INSULATOR SEGMENTATION

Usiholo Iruansi [email protected]

School of Engineering Supervised by Prof. Jules-Raymond Tapamo and Dr. Innocent Davidson

Due to the increase in the scope of power line systems, traditional defects detection methods are far from enough to meet the growing demand especially in the context of renewable resources. Failure caused by insulator defect has a deep impact on the transmission and distribution system. Faulty insulator causes the change of voltage and electric current, which causes great damage in power line system [1], [2] and [3]. It is therefore important to monitor and inspect the insulator to assess damage that could be caused by aging or any accident on the power line. Computer vision has been identified and is being investigated as a tool to solve this problem more safely, accurately and speedily. Identifying the region where the insulator is located is crucial in the process of assessing its status. The insulator can then be segmented and fed to defect detector. In this paper we proposed an insulator segmentation framework from plain (single colour) and complex (cluttered) background using active contour [4]. The active contour model successfully segments insulators from a plain and complex background. For some complex backgrounds, sometimes due to noise, performance is improved when the thresholding method and post processing is applied in combination with active contour model. This method is more efficient, flexible than the classical methods such as thresholding and utilizing gradients [4]. REFERENCES [1] Xinye Zhang, Jubai An, Fangming Chen, "A Simple Method of Tempered Glass Insulator Recognition from Airborne Image," in International Conference on Optoelectronics and Image Processing, 2010, pp. 127 - 130. [2] He Wei, Yang Fang, Wang Jingang, Yang Hao, Chen Minyou and Yao Degui, "Inverse Application of Charge Simulation Method in Detecting Faulty Ceramic Insulators and Processing influence from Tower," IEEE Transactions on Magnetics, vol. 42, no. 4, pp. 723 - 726, April 2006. [3] Xingliang Jian, Jihe Yuan, Lichun Shu, Zhijin Zhang, Jianlin Hu and Feng Mao, "Comparison of DC Pollution Flashover Performances of Various Types of Porcelain Glass and Composite Insulators," IEEE Transactions on Power Delivery, vol. 23, no. 2, pp. 1183 - 1190, April 2008. [4] Tony F. Chan and Luminita A. Vese, "Active Contour Without Edges," IEEE Transactions on Image Processing, vol. 10, no. 2, pp. 266 - 277, February 2001.

44

B9 THE ROLE OF ETHYLENE POLYGLYCOXYL PENDANT UNITS ON THE TERPY BASED PLATINUM(II) COMPLEXES. A KINETIC AND MECHANISTIC STUDY.

Meshack Sitati

[email protected] School of Chemistry and Physics

Supervised by Prof. Deogatius Jaganyi The rate of Chloride substitution from [Pt{(4’-ethylglycoxyl)-2,2’:6’,2’’-terpyridine}Cl]CF3SO3, Pt(eg), [Pt{(4’-diethylglycoxyl)-2,2’:6’,2’’-terpyridine}Cl]CF3SO3, Pt(deg) and [Pt{(4’-triethylglycoxyl)-2,2’:6’,2’’-terpyridine}Cl]CF3SO3, Pt(teg) by a series of biological nitrogen donor nucleophiles, viz. pyrazole (Pz), triazole (Tz), imidazole (Im), 1-methylimidazole (MIm) and 1,2-dimethylimidazole (DIm) under pseudo-first-order conditions in methanol using UV/Visible spectrophotometry were investigated. The analysis of kinetic trend on the candidate complexes show that the first carbon-oxygen pendant bond plays a crucial role in regulating the electron density donated by the polyethylenegycoxyl fragment. This is reflected in the insignificant change in the reactivity as the chain length is increased with the trend not correlated to electronic factors. The trend in the reactivity slightly increases from Pt(eg) to Pt(teg) due to reduction in steric hindrance imposed by the ethylene glycoxy unit. The obtained kinetic data is supported by the DFT calculations that reveal a less electrophilic Pt (II) metal centre for complexes bearing the 4’-substituent. The temperature dependent studies support an associative mode of activation where bond formation in the transition state is favoured.

45

B10

PHYTOCHEMICAL AND BIOTECHNOLOGICAL STUDIES OF ZANTHOXYLUM CAPENSE: AN ENDANGERED SOUTH AFRICAN MEDICINAL SPECIES

Olusola Bodede


Supervised by Dr Roshila Moodley and Dr Shakira Shaik Zanthoxylum capense is a native South African plant characterized by thorns spread all over the trunk to its branches and easily identified by a strong citrus smell produced by the leaves when crushed [1]. It is an old remedy for epilepsy but has also found several ethnobotanical applications in the treatment of snake bite, gastro intestinal disorders, flatulent cholic and syphilis [2], but with only limited scientific information justifying these traditional uses. Habitat destruction, over exploitation and problematic seed germination pose a great threat to the conservation of this important medicinal plant [3] making it imperative to isolate and identify the bioactive compounds of the plant, bulk up the important compounds and save the species from extinction. A comprehensive study to isolate the therapeutic constituents of Z. capense was embarked upon vis-à-vis elicitation of some compounds of interest and micropopagation of the plant using in vitro bio-processing technology. The phytochemical study has yielded a flavonoid (catechin), two triterpenoids (lupeol & sitosterol), one carotenoid (lutein), and pheophytin A. Structures of the compounds were confirmed using 1D & 2D NMR, GC-MS, UV and IR. Nodal explants of Z. capense were cultured on full strength Murashige & Skoog (MS) basal medium supplemented with varying concentrations of kinetin or (BAP) following a 6hr sterilization period with Sodium dichloroisocyanurate (NaDCC) for shoot multiplication. The best result was obtained from 1.0 mgL-1 Kinetin (92% of explants had shoots ranging from 1 to 6 after 9 days in culture). It could be inferred from this work that the potency of Z. capense against the cited diseases may the due to the presence of flavonoids and triterpenoids in it. Also, kinetin supplemented tissue culture media can be used to micropopagate Z. capense. REFERENCES 1. Schmidt, E.; Lotter, M.; McCleland, W., Trees and shrubs of Mpumalanga and Kruger National Park. Jacana Media. 2002. 238 2. Amabeoku, G.; Kinyua, C., Evaluation of the anticonvulsant activity of Zanthoxylum capense (Thunb.) Harv.(Rutaceae) in mice. Int. J. Pharmacol. 2010, 6 (6), 844-853. 3. Semenya, S.; Potgieter, M.; Erasmus, L., Ethnobotanical survey of medicinal plants used by Bapedi traditional healers to manage HIV/AIDS in the Limpopo Province, South Africa. J. Med. Plants Res 2013, 7 (8), 434-441.

46

B11

DEVELOPMENT OF MODELS FOR SUSTAINABLE REHABILITATION OF SMALL-SCALE WATER INFRASTRUCTURE (SWI): A CASE STUDY IN

MAKHUDUTAMAGA LOCAL MUNICIPALITY IN THE LIMPOPO PROVINCE

Malekeng Sylvester Selala [email protected]

School of Engineering Supervised by Dr Aidan Senzanje

There is a growing need for appropriate management strategies for rural small-scale water infrastructure (SWI) owing to their lack of maintenance and rehabilitation. SWI are defined as any technical hardware used by rural communities to supply water for their day-to-day activities. Despite their importance in rural livelihood improvement, about 21% to 90% of them remain in the state of disrepair at any given time. In order to sustain the benefits gained from them, their maintenance and rehabilitation need to be improved. The main objective of this study was to develop a model (framework) for sustainable rehabilitation of rural SWI using nonparametric statistical correlations to select factors of significant influence on the sustainability of SWI operation and maintenance (O & M) as well as rehabilitation. This study was conducted in rural communities of Makhudutamaga local municipality in the Limpopo Province of South Africa. A total of 15, functional (7) and dysfunctional (8) SWI distributed over 15 communities were studied. Data was collected using structured questionnaires and 100 SWI beneficiaries were interviewed. The requirements for sustainable SWI rehabilitation were derived from available literature. The results of this study indicated that the requirements for sustainable rural SWI rehabilitation can be categorized into socio-institutional, financial and technical factors. All these factors were crucial to SWI sustainability and SWI rehabilitation. Issues which contributed significantly to sustainability of O & M and rehabilitation (at p < 0.01) were: beneficiaries assuming ownership of the SWI, willingness of beneficiaries to take responsibility for managing the SWI (r (98) = 0.31, p < 0.01), establishment of management structures (r (98) = 0.69, p <0.01), establishment of fund raising mechanisms (r (98) = 0.21, p < 0.01), the potential to improve beneficiaries’ willingness to pay for O & M and rehabilitation of the SWI (r (98) = 0.21, p < 0.01) and ensuring that the SWI provides adequate water of good quality (r (98) = 0.41, p < 0.01). . A user-friendly flowchart-type rehabilitation model, based on the above mentioned issues, was developed for SWI beneficiaries responsible for SWI management. This study recommends that beneficiaries should establish the necessary structures proposed in the model in order to improve the sustainability of the small-scale water infrastructure and that future research should focus on ways to build sustainable management structures and fund raising mechanisms for SWI O & M and rehabilitation.

47

B12

ADAPTIVE PARAMETER SELECTION FOR GRAPH CUT-BASED CELLS SEGMENTATION

Oyebode Kazeem


Supervised by Prof. Jules-Raymond Tapamo The current formulation of graph cut [1] struggles to segment tiny elongated cells; it also produces poor segmentation results of non-uniform illuminated cell images with unclear boundaries. Graph cut segmentation approach provides a platform for segmenting images in a globally optimised fashion. The graph cut energy function includes a parameter that adjusts the relative importance of its data term to its smoothness term. However; one of the challenging tasks in graph cut segmentation is finding a suitable parameter value that suits a given segmentation. A suitable parameter value is desirable in order to avoid image over-segmentation or under-segmentation [2]. To address the problem of trial and error in manual parameter selection, we propose an intuitive and adaptive parameter selection for cell segmentation using graph cut. Firstly, cell boundary extraction is carried out to discover cell boundary pixels. Secondly; cell image is transformed logarithmically in order to shrink the dynamic range of foreground pixels. The extracted cell boundary pixels together with the logarithmically transformed foreground pixels are used to dynamically adjust and contextualize the parameter value of the graph cut energy function. The proposed framework outperforms previously proposed cell segmentation methods [3] using graph cut, with an accuracy of 92.1%. REFERENCES [1] Vicente, S., Kolmogorov, V., Rother, C., "Graph cut based image segmentation with connectivity priors," in Conference on Computer Vision and Pattern Recongnition, 2008. [2] O, Peng B & Veksler, "Parameter Selection for Graph Cut Based Image Segmentation," pp. 1-10, 2008. [3] Al-Kofahi Y, Lassoued W, Lee W, Roysam B e, "Improved Automatic Detection and Segmentation of Cell Nuclei in Histopathology Images," vol. 57, pp. 884-852, 2010.

48

C1

EFFECTS OF SOCIO-ECONOMIC CHARACTERISTICS AND TASTE ON CONSUMERS’ WILLINGNESS TO PAY FOR ORGANIC BEEF

Phumelele Kunene

[email protected] School of Agriculture, Engineering and Science

Supervised by Dr Unathi Kolanisi The use of synthetic chemicals in conventional beef production has generated consumer concerns regarding health and safety. Although the production of organic beef does not promote the use of synthetic chemicals, information on its market demand and prospects in South Africa is limited. The main objective of this paper was to assess consumers’ willingness to pay (WTP) a premium for organic beef. Over 75% of consumers were willing to pay a premium for organic beef, with a majority of 52% willing to pay a 25% premium. Consumers valued organic beef; taste and safety were important attributes such that even those who did not perceive it to be safer than conventional beef were willing to pay a premium. Metropolitan consumers were most likely to be willing to pay despite the fact that organic beef is produced on communal lands surrounding the smaller cities. Income was directly proportional to consumers’ WTP, whilst too little and too much education adversely affects consumers’ WTP. It can be concluded that there is a high demand for organic beef on the South African beef market and consumers are willing to pay a premium.

49

C2

EFFECTIVENESS OF COBALT FERRITE-DOPED CARBON NANOTUBES FOR THE ADSORPTION OF RHODAMINE B FROM AQUEOUS SOLUTIONS

Oluwaseun A. Oyetade


Supervised by: Prof S. B. Jonnalagadda, Prof B. S. Martincigh and Dr V. O. Nyamori The efficiency of cobalt ferrite (CoFe2O4) nanoparticles, acid-functionalized multiwalled carbon nanotubes (MWCNT-COOH) and cobalt ferrite-doped nanocomposites for the removal of the dye, rhodamine B, by adsorption from simulated aqueous solutions was investigated by carrying out a series of batch adsorption experiments. The adsorption capacity and percentage efficiency were evaluated at varying pH conditions, contact times, adsorbent doses, initial dye concentrations and temperatures. The effect of increasing percentages of MWCNT-COOH on the nanocomposites was also studied. Among the various adsorption isotherms tested, the Langmuir isotherm provided the best fit to the equilibrium data obtained. The kinetics of adsorption was fitted to the pseudo-first order, pseudo-second order, Elovich and intraparticle diffusion models. The pseudo-second order model best described the kinetics data showing the lowest values for the sum of squared residuals. The thermodynamic parameters, ΔH°, ΔS° and ΔG°, were obtained over a temperature range of 20 °C – 45 °C. The thermodynamic studies showed that adsorption was spontaneous, endothermic and enthalpy-driven, except for one of the doped nanocomposites for which adsorption was exothermic. A good desorption of the loaded adsorbents was obtained by using acetone and ethanol with a desorption efficiency in the range of 60 – 94%. The adsorbents used in this study proved to be good materials for the remediation of wastewater polluted with the dye, rhodamine B. They were also recyclable without much loss of activity.

50

C3

SOIL CHARACTERIZATION AND PLANT ASSESMENT FOR PHYTO-REMEDIATION OF HEAVY METALS FROM SEWAGE SLUDGE APPLICATION

Awonke Mbangi

[email protected] School of Agriculture, Earth and Environmental Science

Supervised by Professor Pardon Muchaonyerwa

The exponential increase in population, high rate of urbanization and growth of industries has given rise to a lot of waste generation. Part of this waste is treated by sewage treatment plants and as a means of disposal it is sometimes applied to the soil. Long term application of sewage has led to accumulation of heavy metals in soils, causing serious environmental problems and posing a threat to plant, human and animal health. The development of remediation strategies is thus of paramount importance in reclamation of heavy metal contaminated soils, and phytoremediation has been found to be a technology that is economically viable and environmentally friendly. Plant species growing from the site of contamination have been harvested and analyzed for heavy metal concentration. These include Amaranths dubius, Solanum lycopersicum, Solanum nigrum, turf grass and an unidentified plant. The results show different levels of uptake by these plants, with turf grass having the highest concentrations of all the metals under investigation i.e. Zn 419 mg/kg, Pb 23 mg/kg, As 11 mg/kg, Cd 3 mg/kg, Cu 81 mg/kg, Hg 6.3 mg /kg, Ni 223 mg/kg and Cr 429 mg/kg. Zinc, lead, copper, nickel and chromium were concentrated far above their toxicity threshold in plants, this indicated a great potential in phytoremediation of the above mentioned heavy metals.

51

C4

CATALYST-FREE SONOCHEMICAL RAPID PROTOCOL FOR THE BENIGN METHODOLOGY AND IMPROVED SYNTHESIS OF PYRAZOLES

Nhlanhla Shabalala


Supervised by Prof Sreekantha Jonnalagadda

A simple, catalyst-free, green synthetic protocol is described for the one-pot synthesis of pyrazoles via multicomponent reaction of aromatic aldehydes, hydrazine monohydrate and ethyl acetoacetate and ammonium acetate in water under ultrasound irradiation. This protocol avoids traditional chromatography and purification steps and it affords highly selective conversion with no byproducts.

Figure 1. Multicom

ponent synthesis of pyrazoles derivatives (5a-i) Development of simple and eco-friendly procedures for synthesis of compounds with biological interest is the driving force for the discovery and design of new bioactive compounds. Multicomponent reactions (MCRs) are gaining importance and are in high demand in modern organic synthesis. It is particularly true in case of heterocycles[1] as those reactions facilitate formation of several bonds in one unit operation.[2, 3] In the recent years, ultrasound irradiation has gained recognition as a clean and advantageous approach in organic synthesis.[4] The sonochemical phenomenon is the result of the interaction of suitable field of acoustic waves with potentially reacting chemical system. Cavitation phenomenon develops high temperature and pressure in the micro environment which creates turbulence and facilitates the mass transfer in the neighborhood. Compared to conventional heating which provides thermal energy in the macro system, ultra- sonification reduces reaction times, improves yields and minimizes side product formation by providing the activation energy in micro environment.[5] As this technology involves energy conservation and minimal waste generation, it is widely accepted as a green chemistry approach.[6] Furthermore, this technique can be applied to a variety of organic syntheses accomplishing better yields, under mild reaction conditions and shorter reaction times.[7] REFERENCES [1] A.N. Author, and A. N. Other, J. Title, Year, Issue, Page.

2

4a-i3

H2O

)))))), 50oC ON

NH

R

5a-i

HO

R

O

O O

2 NH2NH2

1

H2O

NNH

NH4OAC

52

C5

IN SACCO DEGRADATION PROPERTIES AND INTER-RELATION OF TEN ROUGHAGES IN THREE DIFFERENT RUMEN ENVIRONMENTS

Masande Katamzi

[email protected] School of Agriculture, Earth and Environmental Sciences

Supervised by Professor Ignatius Nsahlai The study was conducted to relate degradation properties of different quality roughages and their interaction with three different rumen environments. Two rumen fistulated jersey cows were fed on veld grass hay adlibitum. The veld grass hay was supplemented with lucerne hay that was added in each trial; 0, 1.5 and 3kg per day. The experiment consisted of three trials that were given 10 days of adaptation period before they commences. Roughage samples were incubated in the rumen for 3, 6, 9, 24, 48, 72 and 96 hours. Used roughages were (MS) maize stover (Zeal Mays), maize leaves (ML), (WS) wheat straw (Tritium sativa), (KK) kikuyu (pennisetum clandenstinum), (EC) weeping love grass (Erograstis curvula), (ECC) weeping love grass at bloom stage (Erograstis curvula), veld grass hays (VGHA, VGHD, VGHC and VGHP) from Airport at Pietermaritzburg, Dundee, Camperdown and below the pens at Ukulinga Research Farm, respectively. Roughages in rumen environments supplemented with lucerne had increased (P<0.0001) slowly degradable fraction (b), potential degradability (PD) and effective degradability (ED) of dry matter. Rate of degradation (c), the potential and effective degradability differed (P<0.0001) amongst roughages in three different rumen environments but the DM solubility (a) did not. Crop residues (MS& ML) had highest degradability properties while straw (WS) had lowest degradability properties between roughages. The pH of the rumen fluid ranged between 5.5 and 7.6 for all rumen environments. Rumen ammonia concentration drastically increased with the increasing levels of lucerne in the diet. It was concluded that roughage degradation differs with the quality and suitability of the rumen environments (1.5E to 3.0E) suggesting that nitrogen supply in the basal feed is a factor driving these changes.

53

C6

USE OF FORAMINIFERAL ASSEMBLAGES IN DETERMINING THE PALAEOCLIMATIC RECORD OF TWO-MILE REEF, SODWANA BAY

Stephanie Vivien Hayman

[email protected] School of Agriculture, Earth and Environmental sciences Supervised by Prof. Michael Schleyer; Ms Fiona Mackay

Benthic Foraminifera are valuable tools in palaeoclimatic studies and are widely used to elucidate the response of benthic communities to past environmental stressors. Sodwana Bay is host to a complex of reefs whose coral communities are close to the limit of their distributional range. Limited foraminiferal research has been conducted on these reefs with none having a palaeoclimate focus. Sediment cores were collected inshore of Two-mile Reef with the aim to assess the impact climate change has had in the northern subtropics of South Africa using a variety of techniques, including sediment characterisation, foraminiferal assemblage analysis, grain-size distribution and isotope analysis. Three intact bioclastic sediment cores 61, 47 and 49 cm in length, respectively designated X, Y and Z, were collected at a depth of 16 m. The coring sites were adjacent and 200 m inshore of Two-mile Reef. All cores displayed well-defined banding with good agreement, confirming their integrity and suitability for comparison. A total of 33 subsamples were analysed from the longest core X, yielding at least 300 Foraminifera from the >125 µm size fraction, identified to the lowest possible taxonomic level. Radiocarbon dating from core X provided a starting calendar age of 800 ± 120 AD. The age of the core signified the slow sedimentation rate on Two-mile Reef and the preservation capabilities of the bioclastic sediment which exceeded expectations along a strongly wind-driven, high energy coast. The cores also provided insight into how past climate has affected calcifying Foraminifera and will supplement additional research on the future effects of climate change on southern African coral reefs.

54

C7

GRASSLAND MANAGEMENT AND ENVIRONMENTAL FACTORS EFFECTS ON SOIL CO2 EMISSION UNDER SMALLHOLDER AGRICULTURE IN KWAZULU-

NATAL PROVINCE

Elkhatab Abdalla [email protected] & [email protected]

School of Agriculture, Earth and Environmental sciences Supervised by Dr Pauline Chivenge

Grasslands have potential to mitigate climate change through their ability to absorb atmospheric CO2. Soil CO2 emissions from grasslands can be influenced by management practices and grass cover. A study was conducted in the KwaZulu-Natal province of South Africa with the objective of evaluating the variability of CO2 emissions under different grass management practices; fertilizer, savory (high intensity grazing), fence, burn and control following three years of treatment. A total of 17 measurements were done from January to December 2013. Soil CO2 emissions were generally higher in the rainy period while in the dry period the emissions were low with no treatment differences. On average, CO2 emission was greatest under fertilizer (0.137 g C-CO2 m-2 h-1) and least under burn treatment (0.084 g C-CO2 m-2 h-1). Savory (0.114 g C-CO2 m-2 h-1) was significantly greater than fence (0.101 g C-CO2 m-2 h-1) and control (0.094 g C-CO2 m-2 h-1). The CO2 emissions were influenced by grass cover with high grass cover, at average 0.0135 g C-CO2 m-2 h-1, having 75.3% greater CO2 emission compared to low grass cover (average 0.077 g C-CO2 m-2 h-1). CO2 emissions increased with increase in net primary production (R2= 0.76) and soil organic C stocks (R2= 0.84). Results from this study will contribute to the ongoing efforts on climate change, through monitoring the effects of grassland management on CO2 emissions and advance information on the balances of ecosystems.

55

C8

INTROGRESSION OF AFLATOXIN AND FUMONISIN CONTAMINATION RESISTANCE GENES IN MAIZE HYBRIDS

Nyasha Chiuraise


Supervised by Prof. John Derera Contamination of maize grain by mycotoxins, such as aflatoxins and fumonisins caused by Aspergillus flavus and Fusarium verticillioides, respectively is a constant threat to food security in southern Africa. Aflatoxins and fumonisins are carcinogenic, teratogenic, mutagenic and immunosuppressive to both humans and livestock. Presently, breeding for reduced mycotoxin contamination is one of the best strategies to lower aflatoxin and fumonisin contamination in maize. Although mycotoxin resistant maize inbred lines have been identified, currently, there are no aflatoxin and fumonisin resistant commercial maize hybrid varieties available to farmers in southern Africa. Decades of research have resulted in the identification of maize inbred lines that are resistant to either aflatoxin or fumonisin accumulation but not to both. Therefore the current study aimed at stacking resistance to the two toxins in one germplasm line or hybrid. The objective of this study was to stack the resistance genes in a single product through introgression of aflatoxin and fumonisin resistance genes from tropical inbred lines into adapted inbred lines used in the subtropical and temperate conditions of southern Africa. Consequently, the resultant 72 single cross hybrids were evaluated for fumonisin contamination and 44 three-way cross hybrids and their progenies (146 S2:3 families) were evaluated for both aflatoxin and fumonisin contamination under artificial inoculation. Five single cross hybrids consistently accumulated low fumonisin levels (<4 ppm) both in the greenhouse and field trials. Three 3-way cross hybrids displayed a combined low contamination levels for both aflatoxins (<5 ppb) and fumonisins (<4 ppm). Four S2:3 families also accumulated low levels of both aflatoxins and fumonisins below the legal limits of 5 ppb and 4 ppm, respectively. High genetic gains and heritability estimates were obtained. Therefore the study indicated a significant progress towards breeding mycotoxin resistant hybrids.

56

C9

ANNUAL WATER, SEDIMENT, NUTRIENT AND ORGANIC CARBON FLUXES IN RIVER BASINS: A GLOBAL META-ANALYSIS AS A FUNCTION OF SCALE

Macdex Mutema

[email protected] School of Agriculture, Earth and Environmental sciences

Supervised by Dr Vincent Chaplot, Prof. Graham Jewitt and Dr Pauline Chivenge The emergence of environmental issues like climate change, water scarcity and pollution requires better understanding of water, sediments, nutrients and organic carbon exports from landscapes. Several studies have identified the sources, pathways and fates at selected locations on the globe ranging in size from 1 m² microplots to basins of thousands of km², but the studies were isolated and a global assessment of the exports is lacking. In this paper, data from 86 ISI journal articles, comprising 498 observations worldwide were analysed to evaluate the impact of selected environmental factors (MAP and MAT: mean annual precipitation and temperature; CLAY and BD: soil clay content and bulk density; S: slope gradient and LU: land use) on the annual exports (RC: runoff coefficients; SL: sediment loads; TOCL: organic carbon l; TNL: nitrogen and TPL: phosphorus losses) from different spatial scales (microplot, plot, microcatchment, subcatchment and catchment). Climate masked the effects of other factors, and variability of annual exports from the scales reflected the impacts of MAP and MAT, and their influence on CLAY, BD and LU. The effects of MAP and MAT extended from local to catchment scale; showing increases in RC, SL, TOCL and nutrient losses (TNL and TPL) with MAP; but MAT had decreasing effect on RC, TOCL and nutrient losses. RC decreased from microplot (21%) to plot (16%), followed by increases to microcatchment (26%), subcatchment (25%) and catchment level (41%) with all the changes explained by changes in precipitation and MAP. The increase of SL from microplot (468 g m-

2 yr-1) to plot (901 g m-2 yr-1) was explained by declining vegetation cover. Forests RC (average 32.2%) and TOCL (24.8 g m-2 yr-1) were high due to high MAP (1351 mm yr-1); however, S (34%) was also crucial. The effects of soil properties (CLAY and BD) and topography (S) on the erosion variables were confined to microplot-microcatchment level with RC, SL and TOCL decreasing with CLAY (or increasing BD), while TNL and TPL increased. SL increased with S, yet nutrient losses declined. These results, contributing to better understanding of water, nutrient and carbon cycles in terrestrial ecosystems, should inform ecosystem management. However, effects of inter-location climate variability pointed to a need for research in specific environments using nested spatio- temporal scales.

57

C1 0

RUNOFF-DERIVED CARBON DIOXIDE EFFLUXES IN A SUB-TROPICAL RIVER BASIN AND POTENTIAL CONTROLS

Humbelani Thenga

[email protected] School of Agricultural, Earth & Environmental Sciences (SAEES)

Supervised by Dr Pauline Chivenge

Terrestrial runoff can export high quantities of dissolved organic matter (DOM) and thus plays a crucial role in the global carbon cycle. Although, both the DOM fluxes and exports from river basins have been well quantified and established, there is still a need to fully identify the link between DOM transport from headwaters to ocean and CO2 effluxes, and pertaining factors of control. This study aimed to quantify the CO2 effluxes from overland flow and to examine the potential controls. Water samples were collected during natural rainstorms in the Thukela River Basin of South Africa under sub-tropical climate from hilllslopes on 1 and 10m2 plots to minicatchment (2.3×105 m²), catchment (1.0×106 m²), large catchment (1.0×107 m²), and watershed (2.5×108 m2) to basin (3.0×1010 m2). Runoff-derived CO2 effluxes from all runoff samples were assessed in the laboratory and compared to DOM content and composition along with rainfall characteristics. The average 2012-2013 CO2 efflux computed along the whole Thukela was 1.65 mgC-CO2 m-2 day-1. Effluxes were greatest on 10m2 (2.95 mgC-CO2 m-2 day-1) and decreased downstream by 68% (i.e. 0.93 mgC-CO2 m-2 day-1) at watershed level. . Henceforth, the highest CO2 effluxes in hillslopes corresponded to lower DOM aromaticity as indicated by specific ultraviolet absorbance at 254 nm, SUVA254 between 1.28 and 1.92 L mgC-1 m-1. In contrast, the lowest CO2 effluxes downstream the basin correlated to high DOM aromaticity (SUVA254 from 3.28 L mgC-1 m-1

at 2.5×108 m2). On average, CO2 effluxes were higher in summer (1.77±0.60 mgC-CO2 m-2 day-1 across all spatial scales) versus winter (0.62±0.26 mgC-CO2 m-2 day-1). This information could greatly advance the validation of carbon cycle models and their predictions in response to global change, while opening the way for practices of basin management aiming at storing more carbon.

58

C11

WATER USE CHARACTERISTICS OF A BAMBARA GROUNDNUT LANDRACE DURING SEEDLING ESTABLISHMENT

Tendai Polite Chibarabada [email protected]

Crop Science, School of Agricultural, Earth and Engineering Sciences Supervised by Prof Albert Modi

Bambara groundnut is slow to establish. This leads to significant non-productive water losses through soil evaporation during the establishment stage. This may have negative implications on water use efficiency (WUE). Strategies to identify bambara groundnut as a water efficient crop and promote it in dry areas should consider understanding water use efficiency and water use characteristics during establishment. This study investigated whether there is an association between seed coat colour of bambara groundnut and water use efficiency. Bambara groundnut seed was obtained from Capstone Seeds, Mooi River, in a mixed seed colour batch. Thereafter, seeds were characterised into four distinct selections based on seed coat colour, namely: plain red, plain cream, cream with brown speckles (brown speckled) and cream with black speckles (black speckled). The experiment was conducted in a growth tunnel at the University of KwaZulu-Natal’s Controlled Environment Facility (CEF). The environmental conditions in the tunnel were 33/27°C (day/night) temperatures, 60-82% relative humidity (RH) and natural day length. The experimental design was a split-plot design with water regimes [25%, 50%, and 75% (control) of field capacity (FC)] as the main factor and bambara groundnut landrace selections as the sub-factors arranged in a randomized complete block design with four replications. Data collected during establishment were variables associated with plant growth (emergence, plant height, leaf number and leaf surface area) and physiology (chlorophyll content index, chlorophyll fluorescence and leaf water potential). Thereafter, seedling water use efficiency was determined. Under water limited conditions, bambara groundnut seedlings showed reduced seedling canopy growth, increased root length and root: shoot ratio. No significant differences (P < 0.05) were observed among the water regimes with respect to the physiological parameters (chlorophyll content index, chlorophyll fluorescence and leaf water potential). Consequently, seedling water use efficiency improved with decreasing water availability. Observed traits were consistent with drought avoidance mechanisms. Dark coloured seeds performed better compared to other selections. This was attributed to the high phenolic compounds which could have possibly led to the enhanced performance during seedling emergence as well as improved drought tolerance and seedling WUE.

59

C12

EFFECTS OF LAND USE AND LAND COVER CHANGES ON WATER QUALITY OF UMNGENI RIVER

Jean Nepomuscene Namugize [email protected]

School of Agriculture, Earth and Environmental Science Supervised by Prof GPW Jewitt

An increase in the world’s population is putting great pressure on natural resources which provide energy and food. This is evident in both developed and developing countries, where urbanization and agricultural activities are evolving. However, the natural resource capacity remains the same. The same situation is observed in the uMngeni Catchment in South Africa, where a Catchment plays a major role in the supply of water and food for the population of more than five million of the two metropolitans of Pietermaritzburg and Durban of the KwaZulu-Natal Province. In this review, the pollutant impacts and relationships between land cover changes and water quality are presented. Various sources of nutrients, nutrient effects on receiving water bodies and impacts on ecosystem services and goods are discussed with the focus on nitrogen and phosphorus components. A literature review on the contribution of atmospheric deposition on the total nutrient fluxes for a water body has been shown to be small, but significant, in the uMngeni Catchment. Hydrological models have been proven to be powerful tools to assess the impacts of land use and land management on the transport of nutrients and sediment in a water body. In this review, the ACRU-Non Point Source (ACRU-NPS) and the Watershed Analysis Risks Management Framework (WARMF) models are briefly presented. A critical analysis of existing literature shows that nitrogen and phosphorus are the major nutrients causing eutrophication in water bodies, even though there are other factors. The effects of eutrophication on the impairments of water quality for various uses are also discussed. A divergence of ideas on the role of impoundments in sediment retention and nutrient export downstream of the dams is identified. Therefore, there is the opportunity of starting a continuous and long-term water quality monitoring system to provide reliable data for policy-makers and researchers working in this particular area and the lessons to be learned will apply in other South African river basins and in the whole region.

60

D1

MODELING AND OPTIMIZATION OF XYLOSE AND GLUCOSE PRODUCTION FROM NAPIER GRASS (Pennisetum purpureum) USING HYBRID

PRETREATMENT TECHNIQUES.

Siphelele Mafuleka1 [email protected]

School of Life Sciences Supervised by Dr E. B. Gueguim Kana

The conversion of lignocellulosic biomass to substrate for biofuel production is hindered by the interlinks of cellulose, hemicellulose and lignin. An efficient and cost effective pretreatment procedure is therefore required. This work modeled and optimized two...ce efficient pretreatment procedures are required...required. This work model and optimize ... hybrid techniques of napier grass pretreatment for xylose and glucose production namely HCl and moist heat (HH) and HCl and microwave (HM) using the Response Surface Methodology (RSM). Furthermore, the released sugars were assessed for biohydrogen production. Four polynomial models were developed to relate the effect of hybrid pretreatments to the pattern of release of xylose and glucose. The coefficients of determination (R2) of 0.83 and 0.97 were obtained for xylose and glucose production models respectively using HH hybrid pretreatment, and 0.90 and 0.80 were obtained for xylose and glucose production models respectively using HM hybrid pretreatment. The optimized pretreatment conditions of HH gave 12.83g/l xylose and 2.28g/l glucose while the optimized HM pretreatment gave 15.06g/l and 2.44g/l xylose and glucose respectively. A xylose to glucose ratio of 6:1 was obtained for the optimized HH pretreatment compared to 6:1 in optimized HM pretreatment. These findings indicate that xylose and glucose production from napier grass can be enhanced by an optimal combination of pretreatments of HCl and moist heat at 4.39% HCl, 93.07˚C for 180 minutes, or using a combination of microwave and HCl at 5% HCl, 500 Watts for 30 minutes. Cumulative biohydrogen productions of 8.57ml and 25.06 ml were obtained using sugars generated from HH and HM procedures respectively. The optimum generation of xylose and glucose from napier grass leverages its potential as substrate for the production of renewable biofuels and various biomaterials.

61

D2

ALTERNATIVE FODDER SOURCES TO SAVE NATURAL GRASSLANDS: INCREASING NAPIER GRASS (PENNISETUM PURPUREUM) PRODUCTION

WITH BIOSLURRY

Londiwe Magagula [email protected]

School of Life Sciences Supervised by Dr Theresa Eversson and Dr Pauline Chivenge

Livestock production is an essential component of the agricultural sector, directly supporting the livelihoods of small-holder farmers and providing a range of social and economic benefits. Livestock production in small-holder systems is often limited by both the unavailability and low quality of feed. Increasing fodder production has become essential in the context of diminishing natural grazing veld for livestock in communal rangeland systems. One way to achieve this is through the application of an organic fertilizer (bioslurry) which is a by-product of the anaerobic digestion of manure and water for biogas production. The aim of this study was to determine the effect of bioslurry on Napier grass production for improved grazing capacity in communal rangelands. The specific objectives were: (1) to implement on-farm trials to determine the effect of growing Napier grass with and without bioslurry, (2) to determine bi-weekly Napier grass production by measuring the longest leaf, number of tillers and, plant height and expressing these variables as growth per time unit, (3) to determine the effect of bioslurry on biomass of Napier grass, and (4) to determine the impact of using Napier grass for supplementary feeding on the current carrying capacity. On-farm field experiments were carried out at three rural homesteads in the Upper Thukela region. Plant growth parameters (length of longest leaf, number of tillers and plant height) were collected bi-weekly and biomass was determined after harvesting the entire crop at the end of the growth season. Soil samples were collected before planting and after harvesting to quantify the plant essential nutrients and how these were affected by bioslurry application. The response to bioslurry varied across the growth parameters and the experimental sites. All plant growth parameters including biomass and soil chemistry were not significantly different (p > 0.05). However, the bioslurry treatment yielded 55% more herbage (25.9 tons ha-1) compared to 11.9 tons ha-1 in the control. In this study it was calculated that the 218 ha communal rangeland at one of the study sites (Potshini) was stocked far above (378 AU) the current grazing capacity (68 AU) according to the veld condition (41.6%). The fodder trials in this study indicated that 17 ha planted with Napier grass which is fertilized with bioslurry will be enough fodder for livestock owners to maintain their current stocking density of 378 AU. This suggests that supplementary feeding with Napier fodder has potential to relieve the pressure on the rangeland allowing increased growth and vigour of heavily grazed veld and consequently sustainable grazing despite the high stocking rate. We conclude that bioslurry can be used as a fertilizer to improve Napier grass production in the Upper Thukela communal rangelands, thereby optimizing land area use by enabling farmers to produce higher biomass to feed more cows on marginal land.

62

D3

UNSYMMETRICAL (PYRAZOLYLMETHYL)PYRIDINE METAL COMPLEXES AS CATALYSTS FOR ETHYLENE OLIGOMERIZATION REACTIONS: ROLE OF

SOLVENT AND CO-CATALYST IN PRODUCT DISTRIBUTION

George Nyamato [email protected]

School of Chemistry & Physics Supervised by Dr Stephen Ojwach

Ethylene oligomerization is the primary source of α-oligomers which find application in the preparation of detergents, synthetic lubricants, plasticizers, alcohols and some copolymers [[1], [2]]. Therefore, this process is of great interest to both academic and industrial researchers in the field. The bidentate ligands 2-(chloromethyl)-6-((3,5-dimethyl-1H-pyrazol-1-yl)methyl)pyridine (L1) and 2-(chloromethyl)-6-((3,5-diphenyl-1H-pyrazol-1-yl)methyl)pyridine (L2) were reacted with NiCl2, NiBr2, CoCl2 and FeCl2 leading to the formation of their respective metal complexes [NiCl2(L1)] (1), [NiBr2(L1)] (2), [CoCl2(L1)] (3), [FeCl2(L1)] (4), [NiBr2(L2)] (5), and [CoCl2(L2)] (6) in moderate to high yields. The complexes were characterized by elemental analyses, mass spectrometry and single-crystal X-ray diffraction for 5 and 6. Solid state structures of 5 and 6 confirmed the bidentate coordination modes of L1 and L2 and formation of monometallic complexes. Complexes 1-6 formed active catalysts for the oligomerization of ethylene reactions when activated with either EtAlCl2 or methylaluminoxane (MAO). The catalytic activities of 1-6 and products formed largely depended on the co-catalyst and solvent system. While activation with EtAlCl2, in toluene produced Friedel-Crafts toluene-alkylated products, the use of hexane and chlorobenzene gave predominantly C4 and C6 oligomers. On the other hand, activation with MAO in toluene led to the formation of mainly C4, C6 and C8 oligomers. The complex structure and reaction conditions such as co-catalyst/complex ratio, time and pressure also influenced the catalytic behaviour of these pre-catalysts [[3]]. REFERENCES [1] R. Malgas-Enus, S. N. Mapolie, Inorg. Chim. Acta, 409 (2014) 96-105. [2] J. Skupinska, Chem. Rev. 91 (1991) 613-648. [3] G. S. Nyamato, S. O. Ojwach, M. P. Akerman, J. Mol. Catal. A: Chem., 394 (2014) 274 - 282.

63

D4

EFFECTS OF SIMULATED ACID RAIN ON GERMINATION AND SUBSEQUENT SEEDLING RECRUITMENT OF TRICHILIA DREGEANA

Chandika Ramlall

[email protected] School of Life Sciences

Supervised by Dr Sershen, Prof. N.W. Pammenter, Dr B. Varghese, Dr S. Ramdhani and Prof. P. Berjak

Recalcitrant seeds of many indigenous African species such as Trichilia dregeana must germinate shortly after shedding in order to remain viable. Acid rain, commonly reported in the forests of South Africa due to increased greenhouse gases, may have significant impact on germination and subsequent seedling establishment of this species. The present study investigated the potential effects of simulated acid rain (rainwater with pH adjusted to pH 3.0 and 4.5 with 70:30, H2SO4:HNO3) on germination, seedling growth and recruitment, and oxidative metabolism in Trichilia dregeana Sond., when grown in its native seed bank. The results suggest that acid rain did not compromise T. dregeana seed germination and seedling establishment significantly, relative to the control (non-acidified rainwater). However, seedlings treated with pH 3.0 rain water exhibited signs of oxidative stress, as well as anatomical and physiological damage typically associated with acid rain. Acid rain induced changes in the species composition, relative abundance and emergence of the different life forms from T. dregeana’s native seed bank. Under conditions of acid rain (particularly pH 3.0), decreased seedling vigour may have interacted with competition to compromise T. dregeana seedling establishment success, relative to the control.

64

D5

XYLITOL REDUCES INTESTINAL GLUCOSE ABSORPTION VIA INHIBITING MAJOR CARBOHYDRATE DIGESTING ENZYMES, SLOWING GASTRIC

EMPTYING AND FASTENING INTESTINAL TRANSIT RATE BUT INCREASES MUSCLE GLUCOSE UPTAKE IN NORMAL AND TYPE 2 DIABETIC RATS: A

MULTI-MODE STUDY

Chika Chukwuma [email protected]

School of Life Sciences Supervised by Dr Shahidul Islam

Objective: The present study investigated the possible mechanism(s) behind the anti-diabetic effects of xylitol using in vitro, ex vivo and in vivo models. Methods: The effect of increasing concentrations of xylitol (2.5% - 40%) on alpha amylase and alpha glucosidase activity, intestinal glucose absorption and muscle glucose uptake was investigated in vitro and ex vivo. For in vivo investigation, the effect of an oral bolus dose of xylitol (1 g/kg BW) on gastric emptying, glucose absorption and digesta transit in the different segments of the intestinal tract was investigated in normal and diabetic rats at 1 hour after the dose administration, when phenol red was used as recovery marker. Results: Xylitol exhibited concentration-dependent inhibition of alpha amylase (IC50 = 21.69%) and alpha glucosidase (IC50 = 17.58%) activities in vitro and small intestinal glucose absorption ex vivo. Xylitol also exhibited dose dependent muscle glucose uptake with and without insulin, although the absorption was not significantly affected by the addition of insulin. Oral single bolus dose of xylitol significantly delayed gastric emptying, inhibited intestinal glucose absorption but increased intestinal digesta transit time both in normal and diabetic rats compared to their respective controls. Conclusion: The data of this study suggest that xylitol reduces intestinal glucose absorption via inhibiting major carbohydrate digesting enzymes, slowing gastric emptying and fastening intestinal transit rate but increases muscle glucose uptake in normal and type 2 diabetic rats.

65

D6

COMPARISON OF OXIDATIVE STATE, ULTRASTRUCTURE AND VIABILITY IN EMBRYONIC AXES OF TWO RECALCITRANT SEEDED SPECIES DURING

CRYOPRESERVATION

Cassandra Naidoo [email protected]

School of Life Sciences Supervised by Professor Patricia Berjak, Prof. Norman Pammenter and Dr Boby Varghese

In addition to being desiccation sensitive, embryonic axes of some tropical recalcitrant seeds may be chilling sensitive. Nevertheless, storage at ultra-low temperature (cryostorage), which requires a rapid dehydration step, is the only option for ex situ germplasm conservation. However, for tropical species, development of seedlings after cooling is often not achieved as shoot production is inhibited by physical and oxidative injury. Many cryopreservation manipulations have been geared towards obtaining shoots after each cryo-related procedure. Embryonic axes from temperate-recalcitrant seeds appear to be more amenable to cryopreservation procedures possibly due to their greater tolerance of drying and cooling. Two economically and agriculturally important species were selected for this study. Lychee sinensis (tropical-recalcitrant) and Quercus robur (temperate-recalcitrant) were studied to assess biochemical differences in oxidative metabolism, ultrastructure and in vitro viability retention between temperate and tropical recalcitrant embryonic axes in response to cryopreservation procedures. The production of reactive oxygen species (ROS), antioxidant activity and ultrastructure of the tissue were related to survival after cryopreservation procedures. Significant differences were found in responses between the tropical- and temperate-recalcitrant axes, particularly consequent upon desiccation, a critical stress-inducing stage that must be survived if successful cryopreservation is to be achieved. Ultrastructure and oxidative state of the axes corresponded to viability data across species. Based on the observations, optimisation of fundamental cryopreservation procedures were successfully applied to L. sinensis and Q. robur.

66

D7

RECOMBINANT CHARACTERISATION OF THE VIRULENCE FACTOR, METACASPASE 5, FROM T. CONGOLENSE

Lauren Eyssen


Supervised by Prof Theresa Coetzer Approximately 60 million people and 46-62 million head of cattle and other livestock, spread across 200 separate active foci from 36 sub‑Saharan countries are estimated to be exposed to African trypanosomiasis. The improbability of a vaccine is as a result of antigenic variation displayed by the trypanosomal parasites. Current drug regimes require accurate diagnosis and disease staging due to their high toxicity. Thus virulence factors, which are essential to the parasite’s growth and survival, have become targets for the development of novel chemotherapies and diagnostic assays. The recently discovered metacaspases have been implicated in caspase‑like activity and cell-cycle regulation and differentiation in T. b. brucei, and T. cruzi and are considered to be virulence factors. The putative metacaspase 5 gene from T. congolense (TcMCA5) was successfully cloned, expressed within inclusion bodies, resolubilised and refolded using immobilised metal affinity chromatography. Recombinant TcMCA5 was successfully refolded as evident by the hydrolysis of the synthetic peptide substrate, Z-Gly-Gly-Arg-AMC. Autocatalytic processing was observed within the inclusion bodies and the products were purified along with the full length recombinant protein. Anti‑TcMCA5 antibodies, raised in chickens, were able to detect native TcMCA5 along with the autocatalytic processed products within the lysate of procyclic T. congolense parasites. .

67

D8

QUANTUM EFFECTS IN PHOTOSYNTHESIS

Adriana Marais [email protected]

School of Chemistry and Physics Supervised by Prof. Francesco Petruccione and Dr. Ilya Sinayskiy

Sunlight energy far exceeding human consumption is constantly incident on the Earth's surface. A class of organisms has perfected a method of harvesting this energy over a period of billions of years: this process is called photosynthesis. Understanding photosynthesis on a microscopic scale is necessary to engineer biologically-inspired artificial photosynthetic systems, which would allow us to utilise renewable sunlight energy with greater efficiency than is presently possible. While vast scale separation has meant a traditional distinction between quantum mechanics and biology, recently evidence of quantum coherence in the primary stage of energy transfer in photosynthetic light-harvesting complexes at physiological temperatures [1,2] has raised the intriguing question of whether non-trivial quantum effects play a role in the efficiency of photosynthesis. While quantum effects in the subsequent stage of primary electron transport in photosynthesis were identified nearly 50 years ago [3], many aspects of this stage of the process are also not well-understood microscopically. We give a brief overview of existing models of the primary stages of energy and charge transfer in photosynthesis, and discuss the open quantum systems models that we have proposed [4,5,6] in the context of a selection of open questions about the processes. REFERENCES [1] Panitchayangkoon et al 2010 Proc. Natl. Acad. Sci. USA 107 12766 [2] Collini et al 2010 Nature 463 08811 [3] Devault and Chance 1966 Biophys. J. 6 825 [4] Sinayskiy, Marais, Petruccione & Ekert 2012 Phys. Rev. Lett. 108 020602 [5] Marais, Kay, Sinayskiy, Petruccione & Ekert 2013 New J. Phys 15 013038 [6] Marais, Sinayskiy, Petruccione & van Grondelle 2014 (in preparation)

68

D9

ANTIDIABETIC EFFECT OF FRUIT ETHYL ACETATE FRACTION OF AFRAMOMUM MELEGUETA IN A TYPE 2 DIABETES RAT MODEL

Aminu Mohammed

[email protected] School of Life Science

Supervised by Dr Shahidul Islam The present study was carried out to investigate the antidiabetic effect of Aframomum melegueta fruit ethyl acetate fraction (AMEF) in a type 2 diabetes (T2D) model of rats. Six-week-old male Sprague-Dawley rats were randomly divided into six groups of seven animals each: Normal Control (NC), Diabetic Control (DBC), diabetic rats treated with 150 mg/kg bw (DAML) and 300 mg/kg bw (DAMH) of AMEF, diabetic rats treated with 300 mg/kg bw of metformin (DMF) and normal rats treated with 300 mg/kg bw of AMEF (NAM). T2D was induced by feeding a 10% fructose solution for 2 weeks ad libitum followed by an intraperitoneal injection of streptozotocin (40 mg/kg bw). After 4 weeks of intervention, non-fasting blood glucose concentrations were significantly decreased and oral glucose tolerance ability was significantly improved in the DAML and DAMH groups compared to the DBC group. Serum insulin and HDL-cholesterol concentrations, body weight and pancreatic β-cell function (HOMA-β) were significantly (P<0.05) increased while polyphagia, polydipsia, serum alanine transaminase, alkaline phosphatase, lactate dehydrogenase, fructosamine, urea, lipid profile and peripheral insulin resistance (HOMA-IR) were significantly decreased in the AMEF treated diabetic rats compared to the DBC group. It was concluded that orally administered AMEF possesses strong anti-T2D activity and could ameliorate most of the T2D-induced abnormalities. Furthermore, isolation and partial characterization of the active principle from AMEF is currently underway to find the compounds responsible for this activity.

69

D10

HYPERLACTATEMIA AND MtDNA POLYMERASE γ GENE MUTATIONS IN HIV INFECTED ZULU PATIENTS ON STAVUDINE-BASED ART.

Doty Okanda

[email protected] School of Lifesciences and Clinical Medicine

Supervised by Dr.Michael Meusel and Dr. Colleen Aldous

Nucleoside reverse transcriptase inhibitors (NRTI) are attributed to mitochondrial toxicity, possibly due to their ability to inhibit the human mitochondrial DNA polymerase γ responsible for the replication of mitochondrial DNA. This study seeks to determine if known polymerase γ gene (POLG) mutations could be associated with the observed high incidence of symptomatic hyperlactatemia (SHL) and lactic acidosis (LA) in HIV infected Zulu patients exposed to NRTI stavudine in their antiretroviral therapy. Fifty nine cases, patients with measured lactate of 3.0-4.99mmol/l (SHL, n=13) and ≥ 5mmol/L (LA, n=46) and 57 controls, patients on stavudine for≥ 24 months and are non-hyperlactatemic were enrolled from Edendale hospital between March-August 2014. Females (73.6%) were 25.67times more likely to be cases [AOR 25.67; 95%CI p= <0.001] as compared to males (26.1%) and the cases presented with SHL/LA between 4 and 18 months on stavudine. Weight loss (98.3%) and the presence of vomiting (40%), loss of appetite (86.2%), abdominal pains (59.6%) and peripheral neuropathy (56.9%) were the clinical parametres documented on the SHL/LA patients files. Genomic DNA isolation from whole blood samples of these patients was performed which yielded 113 DNA samples of sufficient yield and purity (A260/A280=1.8;A260/A230=2.0) for subsequent allelic discrimination PCR analysis. Association of these known mutations with hyperlactatemia in our study population would be statistically significant if P<0.05. The findings of this study could offer an understanding on genetic predisposition in the hyperlactatemia cases. In addition to the already known clinical risk factors, new patients of antiretroviral drugs can be tested for these polymorphisms for an informed drug choice. It would also benefit patients who are not using other HAART combinations due to resistance, toxicity or allergy.

70

D11

NOVEL PYRIMIDINE: SYNTHESIS, CHARACTERIZATION AND THEIR ANTICANCER POTENTIAL

Oluwole Samuel Aremu [email protected]

School of Chemistry and Physics Supervised by Prof Neil Koorbanally

Pyrimidine derivatives have shown antitubercular, analgesic, anti-inflammatory, antibacterial, antimalarial, antifungal, antitumour and anti-HIV activity. The number of molecules based on the pyrimidine scaffold has increased in the last decade. Two areas of current medicinal interest are the resistance to currently used antibiotics and the increase in the number of reported cancer cases. Synthesizing novel pyrimidine compounds with antibacterial and anticancer activity can contribute to developing lead drugs, which could add to the many antibiotics currently used and provide alternatives when microbes become resistant to the more popularly used antibiotics. Likewise, novel pyrimidines with anti-cancer activity can contribute to lead drugs which can be used in the fight against cancer. In this work, we have synthesized three small libraries of pyrimidines; (i) 7-amino-5-(4-aryl) 2,4-dioxo-1,3,4,5-tetrahydro-2H-pyranopyrimidin-6-carbonitriles, (ii) 5-aryl-1,3,7,9-tetrahydro pyridodipyrimidin-4,6-dione-2,8-dithiones and (iii) 6-aryl-1,3-dimethylpteridine-2,4-diones. We have used a one pot synthesis involving pyrimidiones, malonitriles and aldehydes with a DABCO catalyst. The compounds were purified by either recrystallization or column chromatography. They were then characterized by NMR spectroscopy and confirmed with Mass spectrometry. The synthesized pyrimidines were also tested for their anticancer activity against HeLa cancer cell lines. Some of the compounds showed the potential to be promising chemotheraupetic agents against cervical cancer. REFERNCES [1] J. M. Quintela, C. Peinador and M. J. Moreira, Tetrahedron, 1995, 51, 5901. [2)] J. B. McNally, J. J. Keiser, J. A. Offord, S. J.Katz, L. B. Giardino, E. Falotico, R. Tobia, A. J. Eur. J. Med. Chem. 1989, 24, 627. [3] A.O. Khan, S. A.Siddiqui, N. Ahsan, W. Verma, S. P.Gilani, S. J. Eur. J. Med. Chem. 2010, 45, 5113. [4] A. K. M. Awadalla, F. M. Eissa, A. A. M. Abou-Seri, S. M. Hassan, G. S. Bioorg. Med. Chem. 2011, 19, 6087.

71

D12

ENVIRONMENTAL DETERMINANTS OF SPECIES COMPOSITION AND DISTRIBUTION IN NORTHERN COASTAL FORESTS IN KWAZULU-NATAL

Kambaj Olivier Kambol


Supervised by Drs Sershen Naidoo and Syd Ramdhani

South Africa’s indigenous forests cover only 0.56% of the country’s total land area but harbour a large proportion of the its floristic diversity. Many of these forests are, however, being eroded as a consequence of anthropogenic pressures. Additionally, forest ecosystems are predicted to be impacted upon by climate change, which has important implications for forest conservation and management. Forests, which are naturally dynamic systems, must therefore be monitored under a changing climate in order design appropriate forest management and conservation strategies. In this regard, botanical assessment tools such as vegetation surveys can be useful for understanding and quantifying plant biodiversity in natural systems such as forests. Soil nutrient and water status are also critical in understanding and predicting seedling recruitment, species composition and species associations in forests. Abiotic factors such as disturbance/encroachment also impact on forest biodiversity. Understanding forest dynamics therefore demands an appreciation of all factors that influence plant establishment, growth and reproduction and hence, forest health. This forms the focus of the present study on the environmental determinants of plant species composition and distribution in selected patches of coastal forests in KwaZulu-Natal (KZN), South Africa. The study was conducted in three coastal forests (viz. Hawaan, Umdoni and Twinstreams) and in understanding how environmental factors (e.g. soil and air temperature and soil nutrient and water content) influence forest floristics along an environmental gradient, aims to predict how climate change is likely to affect forest flora and hence, forest health.

72

POSTER ABSTRACTS

P1

EVALUATION OF ORGANOCHLORINE PESTICIDES (OCPs) RESIDUES IN SEDIMENT, AND WATER DURING WINTER SEASON OF MSUNDUZI RIVER,

SOUTH AFRICA

Gbadebo Adeyinka [email protected]

School of Chemistry and Physics Supervised by Dr. Brenda Moodley

Organochlorine pesticides (OCPs) are major classes of persistent organic pollutants (POPs) listed under the Stockholm convention which have been a major environmental concern to the international community (1).They are used as pesticides and fungicides and as well are used as vector control (2). Once they are released into the environment, they persist for long period of time due to their stability against chemical, photolytic and chemical degradation. There is limited information on the concentration and distribution levels of OCPs from rivers in the KwaZulu-Natal province. This has prompted our investigation of 13 OCP residues in the Msunduzi River which receives its runoff from anthropogenic, agricultural and industrial activities which all contribute to OCP pollution levels in the river ecosystems. Sediment and water samples were collected at ten sites along the river in July 2013 during the winter period. Water samples were kept at – 4 oC prior to extraction, sediment samples were dried and sieved. The sediment samples were extracted by ultrasonic bath with dichloromethane and water samples were subjected to liquid- liquid extraction using dichloromethane. Samples were cleaned up using multi-layered acidic/basic silica gel. All the quality assurance steps were thoroughly observed. Samples were analysed for OCPs using GC-MS. The results showed that all 13 OCPs were detected with total concentrations ranging between 1126.46-8974.69 (mean 3309.09) ng/g and 57.08-510.08 (mean 178.52) ng/mL in sediment and water respectively. Among the OCPs evaluated the DDT isomers were predominant in both sediment and water samples. Indicative ratios and indicative indices revealed that aged long weathering and anaerobic degradation of DDT to DDD in the water ecosystem over a period of time could be possible (3). Conversions of aldrin to dieldrin could be the main reason for higher concentrations of dieldrin over aldrin being observed. The total concentrations of OCPs in this present study was lower compared to that obtained in the Jukskei River catchment area in Gauteng, South Africa and higher than the tolerable concentration level set by the EU, which showed that South African rivers could be more polluted compared to other developed countries. REFERENCES [1] United Nation Environment Programme (UNEP) 2001. Stockholm Convention on Persistent Organic Pollutants. Geneva Switzerland. [2] Eqani, SAMAS.; Malik, RN.; and Mohammad A (2011). The level and distribution of selected organochlorine pesticides in sediments from River Chenab, Pakistan, Environ Geochem and Health. 33: (1) 33-47. [3] Bouwman, H. (2004). South Africa and the Stockholm convention on persistent organic pollutants. S. Afr. J. Sci. 100: 323-328.

73

P2

MESOSPHERE-LOWER THERMOSPHERE PLANETARY AND TIDAL WAVES STRUCTURE OVER SOUTHERN HEMISPHERE USING HF SUPER DARN HF

RADAR

Perfect P. Chifoto [email protected]

School of Chemistry and Physics Supervised by Proff. Sivakumar Venkataraman

Mesosphere-Lower Thermosphere planetary and tidal wave interaction using meteor radar observations over SANAE (72oS, 3oW) are discussed. Summary plots from Radar data are analysed together with SANAE and HALLEY radar field of view. Hourly continuous zonal and meridional wind measurements in the MLT region for the year 2007 are used for the present analysis where by diurnal and semidiurnal tidal amplitudes are estimated from mean winds and are subjected to wavelet analysis to reveal 10 day wave interaction. Wavelet analysis revealed tidal variability at planetary scale waves , with periods ranging from 7 to 30 days. This makes it possible to investigate the day-to-day of tidal waves with planetary waves, seasonal and variation of these waves at major dynamical events . REFERENCES [1]Detrick, D. L., and Rosenberg, T. J.: cosmic [2]Andrews, D. G., Halton, J. R, and Leovy, C. [3]Greenwald, R. A., Baker, K. B., Dudeney, J.

74

P3

IDENTIFICATION AND FUNCTIONAL ANALYSIS OF LIGNOCELLULOSE-DEGRADING ENZYMES GENES FROM A BACTERIAL METAGENOME FROM

EUCALYPTUS SPP. WOODCHIPS

Chika Nnadozie [email protected]

School of Life Sciences Supervised by Dr Roshini Govinden and Prof. Johnson Lin

As a result of problems such as uncertainty of availability of fossil fuel with time and climate change, biofuels derived from plant materials present a source of an alternative renewable energy. Locally in KwaZulu-Natal, sugar cane bagasse is abundantly available and could be used for biofuel production. Lignocellulose-degrading enzymes are keys to efficient and effective deconstruction of lignocellulosic biomass releasing sugars for fermentation to bioethanol. Through Metagenomics and high throughput sequencing, the majority of previous studies have identified genes encoding enzymes involved in deconstruction of the major polysaccharides in plant cell wall from different environments. This study aims to carry out de novo assembly of the metagenome from Eucalyptus spp. woodchips in order to identify possible carbohydrate-active enzyme genes present within the consortia. The prokaryotic inhabitants of the Eucalyptus spp. woodchips were isolated. Genomic DNA sequences obtained from high throughput sequencing by Illumina was analyzed using the Metagenome Rapid Annotation Subsystem Technology (MG-RAST), to unravel taxonomic composition and potential for accessory enzymes genes involved in LB deconstruction. Preliminary analysis revealed that there are approximately 350 bacterial genera; >80% proteobacteria, >11% bacteriodetes, >5% actinobacteria and acidobacteria. In terms of function, most of the sequences are linked to carbohydrate, protein and lipid metabolism. A smaller fraction was associated with degradation of polysaccharide and aromatic compound. Results to date indicate that the metagenome is appropriate for such identification.

75

P4

STUDIES ON APPLICABILITY OF SPACE-BORNE DATA FOR ADDRESSING AIR

POLLUTION AND ITS HEALTH IMPACTS OVER SOUTH AFRICA

Sangeetha Venkataraman (Sangeetha S.K) [email protected] or [email protected]

School of Agricultural, Earth and Environmental Sciences Supervised by Dr. Michael Gebreslasie and Dr. Caradee Wright

In order to understand the human health impacts of air quality, both currently and in the future, it is necessary to understand the air quality of South Africa as a country and indeed even southern Africa, as there is transport of pollutants across cities, provinces and countries. There is a dearth of air quality data in many areas of South Africa as the monitoring stations are usually located in highly populated areas and do not adequately cover all parts of the country or the region. Thus, it is difficult to characterize the air quality of areas outside of these monitored stations and furthermore without understanding the regional sources and transport of air pollutants, it is not possible to fully understand the air quality at specific sites. Satellite observations are valuable as they may complement sparsely distributed ground monitored air quality data and assist in determining the temporal and spatial distribution and variation of air pollutants. The work in this study aims to explore satellite air quality measurements and their applicability to health impacts and air quality research. Here, we address the importance of such a study over South Africa and explore different in situ and space borne ground based data.

76

P5

PHYTOCHEMICAL COMPARISON OF TWO INDIGENOUS MISTAKEN MEDICINAL PLANTS OF KZN, BRIDELIA MICRANTHA AND SIDEROXYLON

INERME AND THEIR ANTIOXIDANT ACTIVITIES

Bongisiwe G.Shelembe1, Email: [email protected]

School of Chemistry and Physics, University of KwaZulu-Natal, Durban 4000, South Africa;

Supervised by Prof Sreekanth B. Jonnalagadda and Dr Roshila Moodley Bridelia micrantha and Sideroxylon inerme are two medicinal plants mainly used in KZN for different medicinal purposes. These plants are being confused due to their characteristics/ physical properties. A Phyctochemical study was conducted to evaluate their differences. Phytocompounds were obtained by extracting Leaves, roots and stem bark of the plants were extracted with organic solvents hexane, ethyl acetate and methanol. Methanol extract was further partitioned with dichloromethane (DCM) and ethyl acetate (EA). Phytochemical investigation of the Stem bark leaves and roots of Sideroxylon inerme (S. inerme) revealed the presence of five pentacyclictriterpenes, one carotenoid and one megastigmane. Friedeline , methylmaslinate , stigmasterol , maytenfoliol , a mixture of α and β-amyrin , apocynol B and lutein were isolated from different parts of Sideroxylon inerme. Whereas the phytochemical studies of Bridelia micrantha revealed the presence of 2 flavonoids, quercetin and quercetin -3-O-β-Glycoside.Crude extracts and some phytocompounds of S. Inerme and B. micrantha were also evaluated as a source of natural antioxidant using DPPH method using ascorbic acid as a standard. Crude extracts from both plants showed a good antioxidant activity with the IC50 of 41.4 µg/mL.

77

P6

ELEMENTAL COMPOSITION OF CYRTANTHUS OBLIQUUS AND LIPPIA JAVANICA USED IN SOUTH AFRICAN HERBAL TONIC, IMBIZA

Nomfundo Mahlangeni


Supervised by Prof. Sreekanth B. Jonnalagadda and Dr Roshila Moodley

Imbiza is a herbal tonic, which has gained popularity amongst South Africans as an immune booster and for the treatment of many minor and chronic illnesses. Main ingredients of Imbiza are extracts from two medicinal plants name Cyrtanthus obliquus and Lippia javanica. The concentrations of various elements in these two plants are examined. The total and water extractable elemental concentrations were determined in both the plants. The elemental concentrations in the water extracts more closely represent concentrations in the herbal tonic. Concentrations of selected elements in C. obliquus bulbs collected from eight market sites around the KwaZulu-Natal province were investigated. The levels of the elements in decreasing order were Ca> Mg >Fe> Zn> Mn > Cu≈Se> Pb> Cr for total concentrations; and Ca> Mg >Fe> Zn> Mn for water extractable forms. Elemental levels in C. obliquus bulbs were dependent on the source, which suggested the importance of collection sites on elemental levels. A high percentage of Zn (77.5–91.5%) was found in water extracts. The levels of selected elements in L. javanica leaves collected from ten different locations around the KwaZulu-Natal province were also investigated. The levels of the elements were found to be in the decreasing order of Ca > Mg> Fe >Zn >Mn > Cu> Se> Cr> Pb>Co >Cd for total concentrations and Ca> Mg >Fe >Zn > Cu>Cr > Pb for water extractable forms. It was evident from the study that the herbal tonic was a good source of Ca and Mg, thus accredited as a viable immune booster and toxic metals were below the recommended levels in the investigated samples.

78

P7 PHASE TRANSFORMATION OF IRON IN HYDROXYAPATITE IN THE

ACTIVATION OF N-OCTANE

aDrushan Padayachee, Venkata D. B. C. Dasireddy, Krish Bharuth-Ram, Sooboo Singh and Holger B. Friedrich


Supervised by Prof. Holger B. Friedrich and co-supervised by Dr. Sooboo Singh Great demand for olefins exists in the chemical industry worldwide [1]. A promising route for the production of these olefins is through the activation of n-octane over hydroxyapatites [2]. Catalytic performance in the activation of n-octane relies on the acid-base properties of the material or on the isolated cations capable of activating C-H bonds [3]. Previous reports stimulated the use of iron oxide and iron phosphate materials in the activation of C-H bonds [4]. Iron (3 wt %) modified hydroxyapatite catalysts were prepared using two methods: firstly, using a co-precipitation technique, for the activation of n-octane, and secondly using a wet impregnation technique, in order to compare the effect of iron substitution in hydroxyapatite on the catalytic activity and the phase transformation of iron. The fresh, reduced and used catalysts were characterized by room temperature powder X-ray diffraction (PXRD). Rietveld refinement on the PXRD patterns of the catalysts showed that iron was substituted in hydroxyapatite using the co-precipitation method but is supported on the surface of hydroxyapatite when the catalyst was prepared using the wet-impregnation method. Mössbauer spectroscopy was used to determine the phases of the iron in both the catalysts, before and after the reaction conditions. The Mössbauer spectra showed the presence of iron(III) oxide phase for both catalysts. After reduction, the iron substituted catalyst showed the presence of iron(II) pyrophosphate (Fe2P2O7) phase and the iron supported catalyst showed the presence of iron(II) oxide phase. Upon re-oxidation both catalysts showed the presence of iron(III) oxide. The same pattern was also observed in variable temperature XRD measurements which showed the reduction of Fe3+ to Fe2+. Thus, the redox mechanism was followed by the catalysts in the activation of C-H bonds in the activation of n-octane as evidenced by Mössbauer spectroscopy and XRD.

[1] S. Albonetti, et al., Catalysis Reviews 38, 413 (1996). [2] V.D.B.C. Dasireddy, et al., Applied Catalysis A: General 467, 142 (2013). [3] V.D.B.C. Dasireddy, et al., Applied Catalysis A: General 456, 105 (2013). [4] F.B. Khan, et al., Hyperfine Interactions 197, 317 (2010).

Fig. 1. Mössbauer spectra of reduced catalysts prepared by (a) wet-impregnation and (b) co-precipitation.

79

P8

REGULATION OF THE THIOREDOXIN SYSTEM IN SACCHAROMYCES CEREVISIAE

Letrisha Padayachee


Supervised by Dr Ché Pillay The thioredoxin system consisting of thioredoxin (Trx), thioredoxin reductase and NADPH plays a significant role in a large number of redox-dependent processes such as DNA synthesis and anti-oxidant defense. Elevated levels of this system have been associated with a number of diseases including cancer and HIV. Understanding the regulation of this network from a systems perspective is therefore essential. However, contradictory descriptions of thioredoxin as both an enzyme and redox couple have stifled the adoption of systems biology approaches within the field. Using kinetic modeling, this discrepancy was resolved by proposing that saturation of Trx activity could be due to the saturation of the Trx redox cycle which consequently allowed development of the first computational models of the thioredoxin system in Jurkat T-cells and Escherichia coli. While these models successfully described the network properties of the thioredoxin system in these organisms, further confirmatory studies were required before this modeling approach could be generally accepted. The aim of this study was to utilize computational and molecular methods to confirm or reject this proposed mechanism for thioredoxin activity. To determine if there is any difference in the kinetic models obtained when thioredoxin was modeled as an enzyme or as a redox couple, representative core models were developed. The data showed that when modeling Trx as a redox couple, the system was able to achieve steady state, there was a re-distribution of Trx into its oxidized form and, thioredoxin reductase affected the rates within the system. On the other hand, when Trx was modeled as an enzyme, the system could not reach a steady state, Trx remained in the reduced form and thioredoxin reductase concentration had no effect on the rates within the system. As these properties could be directly tested in vitro, we sought to directly confirm which model was correct. The thioredoxin system from Saccharomyces cerevisiae was cloned, expressed and purified and substrate saturation curves were generated using insulin as a model substrate. The data showed that the system reached steady state and with increasing concentrations of insulin, the system saturated with a progressive re-distribution of the thioredoxin moiety into its oxidized form. Further, increasing the thioredoxin reductase concentration increased the flux through the system. Collectively, the results obtained through in vitro analyses provided unambiguous support for the thioredoxin redox couple model. These results will enable the construction of a complete computational model of the yeast thioredoxin system and provide a basis for the analysis of this network in a number of pathologies.

80

P9

ELEMENTAL DISTRIBUTION AND UPTAKE BY WATERCRESS (NASTURTIUM AQUATICUM) AS A FUNCTION OF WATER QUALITY

Kimona Kisten


Supervised by Prof. Sreekanth.B. Jonnalagadda and Dr. Roshila Moodley Watercress (Nasturtium aquaticum), is an edible plant commonly found in Southern Africa, which grows both on terrestrial and aquatic environment. The elemental concentrations in the plant and surrounding water (growth solution) were investigated to determine its nutritional value and the impact of water quality on uptake by the plant. The concentrations in the leaves, roots and water were analyzed at eight different sites along the east coast of KwaZulu-Natal. Elemental concentrations in the leaves/roots (μg g-1, dry mass) and water exchangeable/total (μg L-1) at Verulam (situated in the northern part of KwaZulu-Natal) were: As (1.2/7.5 and 0.053/0.09), Ca (18272/26091 and 0.336/7.15), Cd (0.9/0.8 and 0.004/0.01), Co (37.2/34 and 0/0), Cr (7/35 and 0.003/0.03), Cu (3/19 and 0.016/0.16), Fe (528/4308 and 0.375/0.6), Mg (3444/1141 and 6.4/7), Mn (110/667 and 0/0), Ni (20/63 and 0/0.01), Pb (16/17 and 0.01/0.02), Se (28/11 and 0.003/0.01) and Zn (102/116 and 0.099/0.36). Elemental uptake was controlled by the plant but water quality did have an impact on uptake. Concentration of metals in the leaves were in decreasing order of Ca > Mg > Fe > Mn > Zn > Cu > Cr > Ni > Pb > Se > Cd > As > Co. The watercress plant was found to be a rich source of essential elements especially Fe and Cr and contained low concentrations of the toxic metals investigated thereby making it safe for human consumption.

81

P10

FIGHTING HUNGER BEYOND THE MILLENNIUM DEVELOPMENT GOALS (MDGs): BIOFORTIFIED PROVITAMIN A MAIZE TO ENHANCE CHICKEN NUTRITIONAL VALUE FOR THE BENEFIT OF RURAL HOUSEHOLDS – A

REVIEW

Feyisayo Odunitan-wayas [email protected]

School of Agricultural, Earth and Environmental Sciences Supervised by Dr. Unathi Kolanisi

Recent statistics show that South Africa (SA) has a high percentage of vitamin A deficiency (VAD) in children and pregnant women. Biofortification of maize with provitamin A is viewed as a cost-effective strategy to combat VAD. However, the biofortified maize is yellow/orange in colour, with sensory properties that are different from those of white maize. The current paper presents a review of the status of VAD compared with interventions across South African Development Communities (SADC), the consumption of chicken meat as protein versus maize, especially by rural households; maize biofortification and its acceptability and the possible effects of using provitamin A-biofortified maize as chicken feed on the quality of chicken meat and eggs. Food is still available in abundance, but its low quality is a challenge as children and pregnant women still continue to be vulnerable. In the SADC region, yellow or orange maize is traditionally used as feed and white maize is the choice for food. Several studies on acceptance of yellow or orange provitamin A-biofortified maize by consumers in sub-Saharan African countries, including countries in the SADC, have generally indicated its low acceptance compared to white maize. The review hypothesis is that the low acceptance of the biofortified maize will be circumvented if the target communities feed their chickens with the biofortified maize and then consume chicken meat and eggs, which will have assimilated provitamin A of nutritionally-significant concentration and other nutrients, including protein, that will contribute to enhancing household food and nutrition security.

82

P11

CYTOTOXICITY OF QUERCETIN-3-O GLUCOSIDE AND 4-(β-D-GLUCOPYRANOSYL-1→4-α-L-RHAMNOPYRANOSYLOXY)-BENZYL

ISOTHIOCYANATE FROM MORINGA OLEIFERA

Fiona Maiyo [email protected]

School of Life Sciences Supervised by Dr. Moganavelli Singh

Of all the potent anticancer drugs currently available in the market, over 60% of them are of natural origin. Moringa oleifera, from the family Moringaceae, is a fast growing tree native to India and is believed to have been introduced to Kenya in the early 1900s, where it is mainly used as a source of vegetable and herbal medicine and in the treatment of various cancers. Crude extracts of the plant have been reported to possess some cytotoxic activity. The present study involved the phytochemical analysis of extracts and purification from M. oleifera which were further evaluated for anti-oxidant activity, cytotoxicity and induction of apoptosis in vitro. Methanolic extracts of the leaves and seeds separated by column chromatography produced quercetin -3-O-glucoside (1), 4-(β-D-glucopyranosyl-1→4-α-L-rhamnopyranosyloxy)-benzyl isothiocyanate (2), lutein (3) and sitosterol (4). The cytotoxicity of compounds 1 and 2 were tested in three cell lines, viz. liver hepatocellular carcinoma (HepG2), colon carcinoma (Caco-2) and a non-cancer cell line Human Embryonic Kidney (HEK293) using the MTT cell viability assay. Apoptosis studies were carried out using the acridine orange/ethidium bromide double staining method. The compounds isolated showed selective in vitro cytotoxic and apoptotic activity against human cancer and non-cancer cell lines, respectively. Compound 1 showed significant cytotoxicity against the Caco-2 cell line with an IC50 of 79 μg mL-1 and moderate cytotoxicity against the HepG2 cell line with an IC50 of 150 μg mL-1 while compound 2 showed significant cytotoxicity against the Caco-2 cell line and HepG2 cell line with an IC50 of 45 μg mL-1 and 60 μg mL-1 respectively. Comparatively both compounds showed much lower cytotoxicity against the HEK293 cell line with IC50 values of 186 μg mL-1 and 224 μg mL-1 respectively.

83

P12

THE EFFECT OF PSIDIUM GUAJAVA AQUEOUS LEAF EXTRACT ON GLYCOGEN SYNTHASE AND PHOSPHORYLASE ENZYMES IN LIVER OF

DIABETIC RATS

Toluwani Tella [email protected]

School of Life Sciences Supervisor: Dr Bubuya Masola and Co-Supervisor: Professor Samson Mukaratirwa

Diabetes mellitus is a heterogeneous disease which currently affects 347 million people worldwide (WHO). It is characterized by chronic hyperglycaemia with disturbances of carbohydrate, fat and protein metabolism resulting from defects in insulin secretion, insulin action or both. Psidium guajava(PG) leaf is known to have a blood-glucose lowering effect in diabetic rats. The aim of the study was to investigate the effect of PG leaf extract on glycogen synthase (GS) and glycogen phosphorylase (GP) activities in liver; and to carry out a phytochemical study of the extract. Diabetes was induced in male Sprague-Dawley rats with a single dose of 40 mg/kg body weight streptozotocin. The aqueous extract of PG leaves was used to treat both normal and diabetic animals (400 mg/kg body weight) for 2 weeks while control animals were treated with the vehicle. The results show that PG lowered blood glucose; restored glycogen synthase activity depressed by diabetes and this was accompanied by reduced glycogen phosphorylase activity and increased glycogen levels . GC-MS analysis of the aqueous extract of PG indicated the presence of phenolic compounds and triterpenoids. We conclude that PG has significant antidiabetic effects, and the effects may be associated with the presence of phenolic compounds and triterpenoids acting to increase GS activity and glycogen storage, and reducing GP activity.

84

P13

EFFECT OF CATALYST ON MULTIWALLED CARBON NANOTUBE QUALITY TOWARDS APPLICATION

Kudzai Mugadza

[email protected] School of Chemistryd Physics

Supervised by Dr. Vincent O. Nyamori, Prof. Genene T. Mola, Prof. Reuben H. Simoyi and Dr. Patrick G. Ndungu*

Current large fossil fuel dependency in energy production is causing pollution effects to the environment. Hence, there is need for alternative energy sources. This in turn is the driving force for extraction of energy from renewable resources. Addition of multiwalled carbon nanotubes (MWCNTs) has high potential in enhancing the technologies available for extraction of energy. MWCNTs are typically synthesised by several methods such as laser ablation, arch discharge and other various types of chemical vapour deposition (CVD). Thermal CVD is the most commonly used synthetic method. The method often employs very high temperatures during synthesis usually from 500-1100 °C [1]. In this work we describe our recent efforts to produce MWCNTs using tailor made non-equilibrium plasma enhanced chemical vapour deposition (PECVD) technique. In this method, temperatures below 300 °C were employed in the production of MWCNTs. Such low temperature enables direct deposition of MWCNTs onto various substrates such as indium tin oxide (ITO) without destroying the substrate properties. Nanoparticles used in the synthesis of MWCNTs and as-synthesised MWCNTs were characterised using scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDX) and Raman spectroscopy. Mono-dispersed nanoparticles with dimensions between 4-10 nm were synthesized and used in MWCNTs synthesis. Typical hollow tubular structures of MWCNTs were observed using TEM. These observations correlated with morphology from SEM which showed the absence of amorphous carbon. Raman spectroscopy showed typical MWCNTs bands, G band and D band due to graphitic carbon vibrations and defects respectively. Hence, non-equilibrium PECVD was used to synthesise MWCNTs using LPG. REFERENCES [1]. M. Ahmad, J. V. Anguita, V. Stolojan, J. D. Carey and S. R. P. Silva, ACS Applied Materials and Interfaces 2013, 5, 3861-3866

85

P14

AN APPROXIMATION BASED ALGORITHM FOR MINIMUM BOUNDING RECTANGLE COMPUTATION

Jules Raymond KALA

[email protected] School of Mathematics Statistics and Computer Sciences

Supervised by Dr S. Viriri and Dr D. Moodley

Shape extraction and analysis is one of the most important task in image processing [1]. The accuracy of the shape features extraction process increases the object recognition rate. Minimum Bounding Rectangle(MBR) is a tool that contributes to the increase of the accuracy of the shape features extraction, particularly it can be used to determine the real aspect ratio [2]. This article focuses on the improvement of the method developed by Chaudhury et al. [3]. This is focused around the determination of the MBR's edges points, using a series of approximations. The proposed method gives more accurate MBR in all the tested situations. In order to demonstrate the accuracy of the proposed method, an experiment is setup based on the comparison of the manually drawn MBR and the ones generated by each of the methods. Results achieved showed that the proposed method outperforms Chaudhuri's method as it consistently produced results closest to the manually drawn MBR. REFERENCES [1] Rafael C. Gonzalez, Richard E. Woods: Digital Image Processing, Pearson Education, Asia, India, (2001). [2] Milan Sonka, Vaclav Hlavac, Roger Boyle: image processing, analysis, and machine vision, ITP. [3] D. Chaudhuri, A. Samal,A simple method for fitting of bounding rectangle to closed regions, Pattern Recognition 40 (2007).

86

P15

MODELLING OF AFRICAN ANIMAL TRYPANOSOMIASIS TRANSMISSION IN KWAZULU-NATAL, SOUTH AFRICA

Nada Abdelatif


Supervised by Professor Henry Mwambi and Dr. Faraimunashe Chirove The African Animal Trypanosomiasis (AAT), or Nagana, is a disease carried by the tsetse fly and affects cattle in South Africa. It is transmitted by two species of flies namely Glossina austeni and Glossina brevipalpis. Both species are mostly prominent in Zululand in South Africa, and lead to production and livelihood losses, resulting in thousands of deaths in cattle and approximately $400 000 in disease control and treatment. The buffalo in the Hluhluwe-Mfolozi game reserve are reservoir hosts of the parasite, and are important factors in the transmission of the disease, especially in areas surrounding the park. AAT has been a serious problem for cattle farmers, leading to significant losses in production and livestock. There have been efforts to collect data in the surrounding farm areas of the Hluhluwe-Mfolozi game reserve, in a step towards enhancing knowledge on the spread of disease, as well as gather information about the tsetse fly population. A study done by Ntantiso [1] showed tsetse population and disease in cattle in three sites in Kwazulu-Natal near the Hluhluwe-Mfolozi game reserve, demonstrating a high prevalence rate of trypanosomiasis in two of the sites and a low tsetse population and low prevalence rate in the third site. The analysis of data is, however, inadequate to provide a definitive solution to AAT. Mathematical models have been used successfully, in many infectious diseases, in simplifying and leading to an understanding of the disease process, while statistical modelling has been used to fit models and estimate the parameters. The approach of mathematical models and statistical techniques will be adopted to the specific case of Zululand and the 3 sites mentioned, and the data will be used to predict the basic reproduction number generated by the mathematical model. The effects climate change has on trypanosomiasis in the region will also be considered. The results of this study will then be used to outline the critical areas that can be targeted by intervention for AAT. REFERENCES [1] Ntantiso, L (2012). Bovine trypanosomosis prevalence at game/livestock interface of Hluhluwe-uMfolozi Game Reserve in Kwa-Zulu Natal Province, South Africa. MSc. thesis, Department of Tropical Veterinary Diseases, Faculty of Veterinary Science, University of Pretoria, pp 71.

87

P16

DOUBLE REDUCTION OF CONSERVATION LAWS OF SOME NONLINEAR PDES IN FLUID DYNAMICS.

Justina Okeke


Supervised by Dr. Rivendra Narain, [email protected] and Prof. Kesh Govinder, [email protected]

The conservation laws for some non-linear wave equations in fluid dynamics are derived via partial Noether approach and direct method. The derived conserved vectors are adjusted to satisfy the divergence relationship. We use the definition of the association of symmetries of partial differential equations with conservation laws and the relationship between symmetries and conservation laws to find a double reduction of the non-linear wave equations.

88

P17

COMPUTATIONAL MODELLING OF THE PEROXIREDOXIN SYSTEM CAN BE USED TO DISTINGUISH THE KINETIC MECHANISM OF HYDROGEN

PEROXIDE DETOXIFICATION IN VITRO.

Beatrice Eagling [email protected]

School of Life Sciences Supervised by Dr Ché Pillay

Oxidative stress, caused by reactive oxygen species (ROS), can have harmful effects on important cellular components and processes which can trigger genome instability leading to cell death. While a host of protein and non-protein antioxidant molecules have evolved to deal with ROS, recent discoveries have shown ROS can act as signal molecules. Cells must therefore maintain a delicate balance of ROS detoxification and ROS-dependent signal transduction. Redoxins are an important family of antioxidant proteins found in almost all living organisms and appear to be key molecules in mediating this balance. In these systems, reducing equivalents from NADPH are transferred to redoxins which in turn reduce other targets. Peroxiredoxins reduce hydrogen peroxide and other ROS and in turn are reduced by thioredoxins and thioredoxin reductase. However there are some discrepancies as to how peroxiredoxins should be described in computational and kinetic studies. Peroxiredoxin activity has been described with both ping-pong and mass action kinetics while other studies have determined the redox potential of peroxiredoxins, suggesting that they are redox couples. In order to resolve these discrepancies, the breakdown of hydrogen peroxide by peroxiredoxins was analysed using three comparable and realistic computational models. The first model described hydrogen peroxide reduction with ping-pong kinetics, and mass action kinetics were used for the remaining models with peroxiredoxin described as a monomer in one model and as a homodimer in the other model. The models were fit to a human peroxiredoxin 2 kinetic dataset and the resulting models were then used to generate new datasets. My results showed distinct responses to the changes in the hydrogen peroxide concentration, confirming that these models can be distinguished in vitro. Further, these results suggest that models based on these distinct mechanisms can have different outputs for the same set of input parameters. The computational models will now be modified to yeast peroxiredoxin parameters to generate datasets that can be validated with in vitro analysis.

89

P18

PORTABLE QKD DEVICE USING THE COW PROTOCOL

Sharmini Pillay [email protected]

School of Chemistry and Physics Supervised by Prof. Francesco Petruccione

Quantum Key Distribution (QKD) is an emerging field of information security. To date, this technology has been implemented for large scale financial and voting purposes, but QKD is a versatile solution which can also be utilised to secure personal transactions. The development of low cost, portable QKD devices can further promote the use of quantum encryption in commercial security systems. Research has been done to design hand-held QKD devices for personal use with ATMs. (ref) These devices use a short-range free space channel to produce a secret key using the polarisation of single photons as qubits. Free space applications of QKD usually utilise polarisation encoding of single photons since the polarisation states do not deteriorate in the turbulent atmosphere. The proposed device uses the Coherent One Way (COW) protocol to exchange a secret key between the two authenticated parties. The COW protocol is a simple, practical protocol which uses the time of arrival of consecutive weak coherent pulses as the bit encoding. The security of this protocol lies in the coherence between consecutive laser pulses. Should decoherence be observed in the monitoring line, the presence of an eavesdropper is inferred. An advantage of using the COW protocol is the small size and low cost of the setup. This is ideal for a hand-held device used for short-range QKD. The COW protocol is not traditionally used for a free space channel due to the fragility of coherence in a turbulent medium. Since this is a short-range device which will not encounter any turbulence, the coherence of the laser beam is not compromised. It is therefore suitable to use the COW protocol under these conditions. We present in this poster, the design of the system, in particular, the conversion from a fibre channel to a free space channel. The system’s alignment is also considered and the lab prototype is presented.

90

P19

MODELLING THE TRANSMISSION DYNAMICS OF BOVINE TUBERCULOSIS IN BUFFALO.

Patrick Phepa


Supervised by Dr Faraimunashe Chirove

Bovine TB is one of the infections which have an impact on the growth of domestic and wildlife animals such as buffalo. The effects have an extended impact on the trade and products of these animals. As a result bovine tuberculosis (BTB) poses a zoonotic threat to the veterinary public health. We propose a mathematical model that studies the transmission dynamics of bovine TB in a buffalo population that seeks to enhance the understanding of BTB infection as a platform for the design of policies towards intervention. The basic reproduction number R0 of the model was calculated to facilitate the qualitative analysis of the model. It was observed that if R0 < 1, the solution converges to the disease free equilibrium point and if R0 > 1, the solution trajectories approach the endemic equilibrium point. Our results suggest that the evolution and the outcome of the disease are determined by the horizontal transmission rates and the indirect transmission rate. Higher values of these transmission rates result in higher levels of infected buffalo and carrier buffalo.

91

P20

CHEMICAL CONSTITUENTS OF LEAVES AND STEM BARK OF ULUZI (Ficus

burtt-davyi)

Olumuyiwa Ogunlaja [email protected]

School of Chemistry & Physics Supervised by Prof. Sreekanth B. Jonnalagadda and Dr. Roshila Moodley

With over 850 species, Ficus (Moraceae) is one of the understudied genera in modern Pharmacognosy, even though for many centuries Animals, Human and other close relatives have depended on its fruits for food while other parts like, leaves, bark, and twigs are utilized for medicinal purposes.[1] Ficus species are known to have wide distribution of secondary metabolite such as flavanoids, glycosides, alkaloids, phenolic acids, steroids, saponins, coumarins, tannins, triterpenes and ascorbic acid in their plant materials[1] hence, the rationale behind this investigation. Ficus burtt-davyi known as Uluzi by the Zulu people is highly adaptable to a wide variety of habitats and has even been known to grow on larger trees (epiphytic) as a strangler fig, as well as on rocks (epilithic) where the roots are able to split the rocks in their search for nutrients.[2] Ethnobotanical survey of Ficus burtt-davyi revealed little or no information.[2]

Leaves and bark were collected from University of KwaZulu-Natal, Westville Campus, KwaZulu-Natal, South Africa and were exhaustively extracted with hexane, dichloromethane (DCM), ethyl acetate and methanol. Column chromatography of the combined Hexane/Dichloromethane extract of the leaves yielded β sitosterol, stigmasterol and campesterol while ethyl acetate extract afforded lutien and pheophytin A. Lupeol and lupeol acetate were isolated from the combined Hexane/Dichloromethane extract of bark. These compounds were identified and characterised by spectroscopic analysis (NMR; 1H-NMR; 13C-NMR; 2D-NMR, GCMS, IR) and comparison of their spectral data with those reported in literature. This is the first account in literature of the phytochemical constituent of Ficus burtt-davyi and it provides baseline information on Ficus burtt-davyi, its ethnobotanical significance as well as the medicinal values. REFERENCES [1]. E. P. Lansky and H. M. Paavilainen, Traditional Herbal Medicines for Modern Times: Figs, The Genus Ficus, ed. R. Hardman, Taylor and Francis Group LLC/ CRC Press, USA. 2011, Vol. 9, 13-50. [2]. J. E. Burrows and S.M. Burrows, Figs of Southern and South-Central Africa, ed. F. Steffens, Umdaus Press Hatfield, South Africa 2003, 192-196

92

P21

AN INVESTIGATION OF THE PHOTOSTABILIZING POTENTIAL OF PLANT EXTRACTS ON SUNSCREEN ABSORBERS IN SKIN-

LIGHTENING PRODUCTS

Moses Ollengo


Supervised by Title Bice Martincigh Skin-lightening preparations intended to lighten the skin and remove heavily pigmented areas weaken the skin’s natural defence to ultraviolet (UV) radiation. The remedy has been the use of sunscreen agents either applied separately or incorporated in the skin-lightening products. Some of these agents are known to degrade in sunlight and hence offer minimal protection to the unsuspecting users. Other agents form photoproducts, that can attack viable cells or sensitize neighbouring biomolecules, and thereby induce free radical formation. Thus, the percentage composition of these agents needs to be kept at set maximum values, which vary from region to region depending on the local regulating authorities. In this work we sought to quantify and study the photostability of the sunscreening agents in randomly selected skin-lightening preparations available in the South African market. A physical blocker, titanium dioxide, was quantified by means of inductively coupled plasma-optical emission spectrometry. Three chemical absorbers were quantified by means of reversed-phase high performance liquid chromatography with photodiode array detection: benzophenone-3, avobenzone and octyl methoxycinnamate. The photostability of the skin-lightening products was investigated by monitoring the UV transmission characteristics of samples smeared on quartz plates at hourly intervals. All the samples were exposed to natural sunlight on a clear sunny day. The samples showed a loss in absorption capacity with increasing exposure times. Those skin-lightening preparations that contained plant extracts or other botanicals, however, showed a recovery of absorptive power after an initial degradation. This study therefore shows that the inclusion of botanical extracts is likely to improve the photostability of skin-lightening preparations.

93

P22

THE USE OF EGG POWDER IN IMPROVING THE FOOD AND NUTRITION SECURITY OF RURAL HOUSEHOLDS OF MKHAMBATHINI

Sithandiwe Khoza

[email protected] School of Agricultural, Earth and Environmental Sciences

Supervised by Dr Unathi Kolanisi Eggs have a potential to mitigate the prevalence of protein-energy malnutrition in rural households of South Africa. The biggest challenge is that eggs have a short shelf-life and rural households are not equipped with modern preservation technologies. Therefore drying eggs into egg powder for longer shelf-life is regarded as a feasible rural household preservation technique. The aim of this study was to explore the utilization of eggs in rural Mkhambathini and assess the acceptability of food products made with commercial egg powder. A total of 110 household representatives participated in the survey. From the survey participants, 20 adult women and 20 youths (16 to 35 years old) voluntarily participated in a series of four focus group discussions (FDGs). A consumer panel of 51 subjects was recruited from the survey participants to assess the sensory acceptability of food products (relish and sandwich) prepared with egg powder. The study findings showed that the rural households viewed eggs as a nutritious food product, which should be included in their diets. However, egg spoilage was regarded as a major challenge. Generally, egg powder had no negative effects on sensory properties of egg relish and sandwich. The overall acceptability of relish and sandwich prepared with egg powder was high and similar to the relish and sandwich prepared with fresh egg. Therefore, rural households can use egg powder in place of fresh eggs when preparing relish and sandwiches to improve their food and nutrition security.

94

P23

DIRECT ROLLING OF METAL POWDER INTO SHEET METAL

Khulani Kunene [email protected]

School of Engineering Supervised by Dr Clinton Bemont

The direct rolling of metal powder into sheet metal is an innovative, low cost powder metallurgy technique which has the potential to be an effective alternative to the currently utilized ingot metallurgy in terms of overall energy utility and material scrap loss. However, the resulting sheet obtained via the direct rolling of metal powder is porous and not fully dense. Therefore, the sheet must undergo a combination of heat treatment (sintering) and pressure application sequence in order to obtain full densification. The purpose of this work is to investigate how the properties of the direct powder rolled sheet can be significantly modified by varying processing parameters such as cold rolling speed, roll gap, applying pressure and sintering temperature during the production of the sheet metal. In principle, if comprehensive understanding of the processing parameters can be developed; a more scientific approach to this form of sheet fabrication technology can be applied rather than the current empirical route. Industrially, sheet metal is processed firstly by casting an ingot and then rolling that ingot into the final desired thickness. The casting of an ingot often becomes a problem for materials that have a high melting point; this in turn increases the overall production costs due to the usage of specialised melting furnaces. Furthermore, materials with high chemical reactivity often react with the cast house tools and forms non-desirable residue on the surface of the material being processed. This property necessitates the need to develop non-conventional refining, melting, and casting techniques which turn to increase the overall production costs. Titanium is one of the key engineering materials and has the most outstanding combination of properties such as high strength-to-weight ratio even at elevated temperatures, outstanding resistance to corrosion in most harmful corrosive environment. Despite this awesome attributes, titanium products are very expensive thus find very little utilization is many engineering applications. This major limitation is caused by the fact that titanium has both high melting point and high chemical reactivity; therefore, this means that using ingot metallurgy to fabricate titanium sheet metal becomes a very complex operation that requires specialised equipment and processing care. Powder metallurgy has the ability to produce continuous sheet metal in fewer steps than the current ingot metallurgy route by directly feeding metal powder into a rolling mill. Therefore, fabricating titanium sheet using this method would drastically reduce the number of processing steps thus reducing the complexity of the entire titanium sheet production process. Furthermore, titanium powder can be directly rolled at room temperature and this alleviates the problem of casting an ingot and also that of chemical reaction between the titanium and casting house tools. However, titanium sheet that has superior qualities that are equivalent or superior to those obtained via the ingot metallurgy route has not been obtained due to the difficulty of producing a non-porous and fully dense sheet.

95

P24

A QUANTUM WALK-BASED MPPT OPTIMIZATION ALGORITHM FOR A STAND-ALONE PV SYSTEM

Makhamisa Senekane


Supervised by Prof. Franceso Petruccione A novel quantum walk-based maximum power point tracking (MPPT) optimization algorithm for stand-alone photovoltaic (PV) system is proposed in this work. A quantum walk is a quantization of a classical random walk algorithm. Since a classical random walk has proven to be a very powerful algorithmic tool, it is prudent then to investigate its quantum analogue, namely a quantum walk, for design of algorithms. The work further covers a numerical analysis of the algorithm in order to determine its suitability as an MPPT optimization algorithm. Simulation results show that this quantum walk-based algorithm can quickly reach maximum power point (MPP), thereby reducing a PV system power loss.

96

P25

FINITE-KEY ANALYSIS OF THE PBC00 PROTOCOL

Kevin Garapo [email protected]

School of Chemistry and Physics Supervised by Prof. Francesco Petruccione

Bennett and Brassard [1], and Ekert [2] independently invented quantum key distribution with the aim of exploiting the laws of quantum physics to accomplish the task of secure secret-key transfer between two agents (Alice and Bob) despite eavesdropping attempts by a proficient adversary, Eve. In the quantum key distribution scenario, the two agents communicate through two channels: a quantum channel and an authenticated (otherwise insecure) classical channel. The eavesdropper is assumed to have full control of the quantum channel and unlimited computational power. However, they can only listen to (and not interfere with) the communication on the classical channel. Several quantum key distribution protocols have been invented. Examples include the following: BB84 [1], E91 [2], B92 [3], SARG04 [4], PBC00 [5]. Unconditional security proofs have been devised for some of the protocols. However, as pointed out in refs [6-8], the proofs only hold for the case of ideal implementation, i.e. given infinite resources and perfect devices. This has led to a knowledge gap between theory and implementation. Finite-key analysis extends security proofs by filling the knowledge gap. We present the result of the finite-key analysis of the PBC00 protocol, which was published in Physical Review A [9]. REFERENCES 1. Bennett, C.H. and G. Brassard. Quantum cryptography: Public key distribution and coin tossing. in Proceedings of IEEE International Conference on Computers, Systems and Signal Processing. 1984. New York. 2. Ekert, A.K., Quantum cryptography based on Bell’s theorem. Physical Review Letters, 1991. 67(6): p. 661-663. 3. Bennett, C.H., Quantum cryptography using any two nonorthogonal states. Physical Review Letters, 1992. 68(21): p. 3121. 4. Scarani, V., et al., Quantum Cryptography Protocols Robust against Photon Number Splitting Attacks for Weak Laser Pulse Implementations. Physical Review Letters, 2004. 92(5): p. 057901. 5. Phoenix, S.J., S.M. Barnett, and A. Chefles, Three-state quantum cryptography. Journal of Modern Optics, 2000. 47(2-3): p. 507-516. 6. Meyer, T., Finite key analysis in quantum cryptography. 2007. 7. Scarani, V., et al., The security of practical quantum key distribution. Reviews of modern physics, 2009. 81(3): p. 1301. 8. Tomamichel, M., et al., Tight finite-key analysis for quantum cryptography. Nat Commun, 2012. 3: p. 634. 9. Mafu, M., K. Garapo, and F. Petruccione, Finite-key-size security of the Phoenix-Barnett-Chefles 2000 quantum-key-distribution protocol. Physical Review A, 2014. 90(3): p. 032308.

97

P26

CHARACTERISATION OF NOVEL GALACTOSYLATED LIPOSOMES FOR LIVER-TARGETED GENE DELIVERY

Seipati Mokhosi 1, Wilson Karubiu2, Ariatti Mario1, Moganavelli Singh1

1School of Life Sciences, 2School of Health Sciences Email: [email protected]

Supervised by Dr M. Singh Cationic liposomes remain the most attractive gene carriers due to ease and versatility in design. In targeted gene delivery, liposomes are coupled to ligands tailored to possess desired characteristics for improved cell-specificity [1]. Carbohydrates have been established as useful targets for the asialoglycoprotein receptor (ASGPR) in liver-directed delivery. The main purpose of this study was to evaluate in vitro behaviour of hepatocyte-targeting liposomes affixed with galactoside derivatives for ASGPR recognition. Furthermore, in silico studies were carried out to assess ligand-receptor interactions. Novel targeted cationic liposomes conjugated with galactosyl ligands viz. Sc6 and Sc9 (acetylated derivate) were formulated using thin film hydration–sonication method using the cytofectin 3β[N-(N',N'-dimethylaminopropane)-carbamoyl] cholesterol (Chol-T) and the neutral co-lipid dioleoylphosphatidyl ethanolamine (DOPE). Characterisation of lipoplexes by transmission electron microscopy (TEM) showed unilamellar liposomes ranging between 80 – 140nm. Upon inclusion of polyethylene glycol 2000 -distearoylphosphatidyl ethanolamine (DSPE-PEG2000) to liposome formulations, lipoplex sizes were more compacted with size ranges of 100-125 nm owing to steric stabilisation. DNA was fully liposome-bound at N:P ratios 2.5:1 – 3:1 following band shift and ethidium displacement assays. Liposomes showed zeta potential of near neutral to positive charges (-5 mV to 15 mV). Nuclease digestion assays revealed good protection with evidence of some nicking. Cytotoxicity studies in the HEK293 and HepG2 cell lines revealed an above 80% cell viability under transfection conditions in both cell lines. Docking studies were performed and calculated binding affinities of ligands to the ASGPR assessed. Both ligand derivatives exhibited binding avidity that was not significantly different. Data gathered to-date suggest the targeted lipoplexes prepared in this study are good candidates for further investigations in liver-specific gene delivery.

98

P27

(PYRIDYL)BENZOAZOLE PALLADIUM (II) COMPLEXES: STRUCTURE AND CATALYTIC HYDROGENATION OF ALKENES AND ALKYNES

Aloice Ogweno


Supervised by Dr. Stephen Ojwach

Catalytic hydrogenation is one of the most preferred methods for reducing unsaturated hydrocarbons to other corresponding saturated products for petrochemical, fine chemical and pharmaceutical industries [1-3]. Neutral and cationic palladium complexes bearing (pyridyl)benzoazole ligands have been found to be active in homogeneous catalysis of hydrogenation of alkenes and alkynes. Their activities rival the comprehensively studied heterogenous palladium complexes.In this contribution, we report the synthesis of (pyridyl)benzoazole palladium complexes and their evaluation as catalysts in the homogeneous catalytic hydrogenation of alkenes and alkynes. The complexes were synthesized as shown in Scheme 1.

N

X

NPd

Cl/MeClCH2Cl2, 24 hN

X

N

N

HN

NPd

PPh3Cl

Y

CH2Cl2, 24 h

Y= Cl (5)Y=BAr4(6)

X=N-H,Cl (1)X=S, Cl (2)X=O, Cl (3)X=N-H,Me (4)

PPh3, NaBAr4

Pd(MeCN)2Cl2 Pd(COD)MeCl

X=N-H (L1)X=S (L2)X=O (L3)

Scheme 1 The complexes were found to be catalytically active with the neutral (1-3) being more active compared to the 4 and the cationic 5 and 6.The nature of the ligand influenced the activity of the complexes with the order being NH > O >S previously observed in other studies [4].

1-6, H2

Toluene, 5 bar, 30 oCR R Scheme 2 REFERENCES [1] D.-S. Wang, Q.-A. Chen,S.-M. Lu,Y.-G. Zhou, Chem. Rev. 112 (2012) 2557–2590 [2] R. Harmon, S. K. Gupta, D. J. Brown, Chem. Rev. 73 (1973) 21–52 [3] P. Frediani, C. Giannelli, A. Salvini, S. Ianelli, J. Organomet. Chem. 667 (2003) 197-208 [4]. (a) A. O. Ogweno, S. O. Ojwach, M. P. Akerman, Appl. Catal. A: Gen. 486 (2014) 250-258 (b) A.O. Ogweno, S.O. Ojwach, M.P. Akerman, Dalton Trans. 43 (2014) 1228–1237 (c) S. Haneda, Z. Gan, K. Eda, M. Hayashi, Organometallics 26 (2007) 6551-6555

99

P28

THE GLUCOCORTICOID RECEPTOR IS SILENCED BY METYHLATION IN

SMALL CELL LUNG CANCER

Kerryn Houston [email protected]

School of Life Sciences Supervised by Dr Paula Sommer Small cell lung cancers (SCLCs) have reduced expression of the normally ubiquitous glucocorticoid receptor (GR) and thus are insensitive to glucocorticoid action. If GR expression is re-introduced into SCLC cells and tumours, the cells die by apoptosis, suggesting that silencing of the GR may play a role in SCLC development. Research has shown that the GR in SCLC is silenced by hypermethylation of its promoter, as treatment of the DMS 79 SCLC cell line with the demethylating agent 5-aza-2′-deoxycytidine (5-aza), results in significant endogenous re-expression of both the GRα and GR-P isoforms. The GR gene has a complex promoter region consisting of nine alternative promoters, the proximal seven of which are clustered together in a 3.1 kb CpG island. The endogenous re-expression seen is mediated by promoters 1B, 1C and 1J, but predominantly 1F, which is methylated in SCLC cells. Thus, silencing of the GR may contribute to SCLC progression. It is therefore proposed that the GR is a novel tumour suppressor gene (TSG) for SCLC. To determine the methylation profile of the GR promoters in vitro, genomic DNA extracted from the SCLC DMS 79 cell line, and the control HEK cell line, was subjected to bisulphite modification. This converted DNA was then used as a template in PCR to amplify GR promoter regions 1B, 1C, 1F and 1J. The purified PCR products were cloned into the pGEM-T Easy vector, purified, and sent for sequencing. Promoters 1B and 1F showed methylation of CpG residues in the DMS 79 cells, but not the HEK cells. These data will serve as a control for bisulphite-specific PCR performed using DNA extracted from biopsy specimens. To establish whether the GR is similarly methylated in vivo, the methylation profile of the GR from SCLC biopsies will be compared to that of non-SCLC as non-SCLC cell lines show no methylation in vitro. The GR methylation profile will also be correlated with age, cancer stage, smoking status, recurrence and death rates. Aberrant DNA methylation occurs in a tumour-specific and gene-specific manner, and due to their consistency, promoter methylation profiles are now recognised as tumour-specific markers. The GR may be an as yet uncharacterised TSG for SCLC.

100

P29

THE VULNERABILITY OF TROPICAL FISHERIES TO CLIMATE CHANGE: A CASE STUDY OF KAPENTA FISHERY OF LAKE KARIBA, ZAMBIA/ZIMBABWE

Sithabile Hlahla

[email protected] School of Agricultural, Earth and Environmental Sciences

Supervised by Professor Trevor Hill Tropical lakes are social-ecological systems that provide resources vital to the survival of aquatic species and human livelihoods [1]. However, there are increasing threats to the sustainability of this resource due to over-population, overfishing, pollution, increased water abstraction, land use change and climate change. Tropical lakes, due to their already high temperatures, are sensitive to climate change [2] and there is growing evidence that the Sub-Saharan region is becoming warmer [3]. While the primary reason for the reduction of fisheries is over-exploitation, climate change is very likely to cause the final collapse in some fish stocks, affecting the fisheries-dependent communities, lake ecosystems and local economies. One such lake is Lake Kariba, the third largest man-made lake in the world. Built in the 1950s, primarily for hydro-electricity, this oligotrophic lake is located on the Zambezi River where it forms the political border between Zambia and Zimbabwe. The lake’s most successful commercial fishery is based on the pelagic 'Kapenta' fish (Limnothrissa miodon) which accounts for two-thirds of the total fish catch. This fishery provides a cheap but high protein nutrition, that sustains livelihoods, contributes to local economic development, poverty alleviation and food security [4]. Recent studies of the Kapenta fish stocks on the Zimbabwean side of the lake have shown an unprecedented recent decline. This concerning downward trend has been attributed to overfishing and climate change; specifically decreasing rainfall, increased evaporation rates and warming in the Kariba region and consequently, warmer lake waters [5]. Despite these emerging research findings, a limited number of publications include the Zambian fishery and the socio-economic dynamics of the Kapenta fishery. This study aims to fill this research gap by applying a more holistic approach: analysing both the Zambian and Zimbabwean fisheries, incorporating historical environmental data, investigating the socio-economic dynamics surrounding the transboundary fishery (policies and fishing practices) and suggesting ways in which the current (if any) adaptation practices can be improved. REFERENCES [1] Vincent, W.F., 2009. Effects of Climate Change. In: Likens, G.E. (ed.). Encyclopedia of Inland Waters, 3, 226-232. [2] Magadza, C.H.D., 2011. Indications of the effects of climate change on the pelagic fishery of Lake Kariba, Zambia—Zimbabwe. Lakes & Reservoirs: Research and Management, 16, 15–22. [3] Davis, C.L., 2011. Climate Risk and Vulnerability: A Handbook for Southern Africa. Pretoria: Council for Scientific and Industrial Research: Pretoria. [4] Ndebele-Murisa, M.R., Hill, T. and Ramsay, L., 2013. Validity of downscaled climate models and the implications of possible future climate change for Lake Kariba’s Kapenta fishery. Environmental Development, 5, 109-130. [5] Ibid.

101

P30

OWNERSHIP BY GENDER AND ITS INFLUENCE ON GOATS AND CATTLE PRODUCTION AMONG THE ISI-TRIBE OF SOUTH AFRICA

Adetoyese Adeyemo


Supervised by Prof. Ignatius V. Nsahlai The study aimed at evaluating goats and cattle ownership and its impacts on productivity in the communal farming system. Also discovering challenges militating against its commercialization and how it could be solved. In each of 3 communities, 30 famers were randomly selected, making a total of 90 across the municipality for questionnaire interview. A focus group discussion was held based on the livestock association that exists along the irrigation scheme. Households headed by male have higher possession of cattle than those headed by female in the ratio 3:1 while a ratio was 2:1 in the possession of goats. Ownership of goats and cattle across the municipality falls between 30% female to 37% male. Use of cattle for cultural purposes (42.34 %) was more important compare with income (22.18%), prestige (18.15%) meat (12.50%) and milk (4.84%)purposes. Goats serve cultural (38.91%), prestige (29.94%) income (19.20%), meat (11.5%) and milk (2.5%) purposes. Farmers pointed out that their livestock numbers increased due to reproduction (40%) and buying (30%). All respondent grazed livestock on communal land without due regard for watering. There are significant differences in female ownership of goats while male ownership in cattle. Of this, 70% mortality was due to diseases, water and feed shortage which have militated against increased livestock production, followed by pilfering, dog attack and poor management practices. There is need for profit maximizing programmes that will cause a perspective shift in the culture towards livestock farming with respect to routine management in feeding, common diseases and breeding. Also establishment of pests and diseases control grazing lands and water availability for agricultural purposes will greatly influence production performance.

102

P31

Cu, Fe, Mn & Zn LEVELS IN FEEDS, FORAGES, STOMACH CONTENTS AND LIVERS OF HORSES IN SOUTH AFRICA

Sheldene Horne


Supervised by Dr Marion Young

An investigation into the trace mineral intakes of horses in South Africa was undertaken to ascertain whether horses are receiving correct and balanced trace mineral nutrition. An in-vitro and in-silicio analysis of forages, feeds, stomach contents and horse livers was conducted to establish trace mineral intakes and body stores of Cu, Fe, Mn & Zn in horses. Fe levels were found to be high to excessive in feeds, forages and stomach contents with 80.5% of the livers showing the same trend thus allaying concerns that Fe is poorly absorbed from the diet. Liver iron levels increased significantly (P 0.001) with age. Mn content of feeds, forages, stomach contents and livers showed adequate supply of this mineral. Cu and Zn content of forages was low compared to NRC 2007 recommended levels while the feeds showed higher than recommended inclusions. Liver analysis showed adequate to high Cu levels while Zn levels tended to be low with 35% of horses with less than adequate liver Zn. Attention needs to be given to the ratios of Fe:Cu:Mn:Zn in feeds when fed in conjunction with forages, to ensure adequate absorption and utilization of these trace minerals in horses and to avoid possible interactions between them.

103

P32

POPULATION STRUCTURE AND BREED RELATIONS OF SOUTH AFRICAN INDIGENOUS GOAT ECOTYPE POPULATIONS USING GENOMEWIDE SNP

DATA

Khanyisile Mdladla [email protected]/[email protected]

School of Life Sciences Supervised by Mr Edgar F. Dzomba and Dr Farai C. Muchadeyi

According to breed history of South African goats the unimproved ecotype populations are the main genetic resource in the development of the commercial meat type breeds, however, their genetic contribution and diversity is not fully understood. To elucidate genetic structure and relations, we have genotyped 192 animals with the Illumina Goat 60K SNP BeadChip. For a comprehensive study approach, representative of the meat type Boer (20), Savanna (21), Kalahari Red (17); the feral Tankwa (25); and unimproved local village ecotypes (99) from four goat-producing provinces (Eastern Cape, Kwazulu-Natal, Limpopo, and North West) were included. The multi-coloured Nguni (iMbuzi) goat breed from Kwazulu-Natal (10) was included for comparison purposes. Overall, 91%, 82.4% 93.7%, 94% and of the total SNPs (51,928) showed polymorphisms in the meat type, feral, village ecotypes, and Nguni goat populations, respectively. Results of population structure by admixture and principal component analyses suggest that Tankwa is distinct from its domesticated counterparts. The first and second principal components explained 6% and 4.2% of the total variation and supported the clustering of populations according to their breed/population type and explained partially their historic origins. At K=5, a considerable source of variation among the goats is clustering of the populations into feral, meat type, and village ecotype together with the Nguni goats. Cluster analysis also illustrated subpopulation diversity within the village ecotype population for the North West and Eastern Cape ecotypes. The level of relatedness between goat populations was investigated by calculation of pair-wise FST. The highest FST values were observed for every pair-wise combination of population with Tankwa (FST = range 0.12 to 0.18) and smallest value was observed among the Limpopo and Kwazulu-Natal ecotypes (FST = 0.001). The undifferentiated genetic unit containing Boer, Savanna and Kalahari Red populations is in keeping with the low FST reported for these breeds and is also consistent with breed history, as these breeds were founded in part by the local ecotype populations. Analyses of this study clearly differentiated the goat populations according to their historical origins, revealed the historic geographical distribution of the local village ecotype populations, and confrimed Tankwa population as genetically distinct from the domsticated counterparts.

104

P33

USING ECONOMIC AND MATHEMATICAL EPIDEMIOLOGY IN INFECTIOUS DISEASES INTERVENTION MODELING: FOCUSING ON HIV MODEL

INCORPORATING SERODISCORDANT COUPLES

Siphiwo Mtshali [email protected]

School of Mathematics, Statistics and Computer science Supervised by Title Dr F. Chirove

Infectious diseases are responsible for a high mortality rate in low -and-middle-income countries and also responsible for a quarter of all annual deaths worldwide. Infectious diseases have a negative effect on the world’s economic growth and reduce the lifespan of the human population. Mathematical and economic epidemiology has been used separately to model and analyze infectious diseases and very little attention has been given to these fields combined. There are lots of infectious diseases in which we could apply the concepts of economic and mathematical epidemiology to investigate the effects of combining the two fields, however, we chose HIV. In the proposed study we formulate discrete epidemiological mathematical models of HIV incorporating Serodiscordant Couples with interventions such as treatment and vaccine and incorporate the value functions to form an epidemiology mathematical model with economics aspects and analyse it to obtain the threshold conditions that determines the choices to use or not to use the intervention strategy by individuals. The model will then be analysed and results will be validated to inform policy formulation as well as verify, strengthen and improve existing public policies in resource-poor settings.

105

P34

QUANTUM SELF-AVOIDING WALKS

Hazmatally Goolam Hossen [email protected]

School of Chemistry & Physics Supervised by Prof. Francesco Petruccione

We review quantum self-avoiding walks. Machida et al study the discrete case on a subspace of the complete Hilbert space [1]. The walk can be self-avoiding in the coin and position space separately or simultaneously. Camilleri et al describe how to implement a quantum walk with a memory register which then enables it to be self-avoiding but only to some extent depending on the strength of the memory recording and back-action [2]. Furthermore, it provides an elaborate comparison with the classical self-avoiding walk and thus, points out that the quantum version, due to its diffusive characteristics, may have applications in quantum simulation. Next, we consider two alternatives to the completely self-avoiding walk so as to eliminate the need of memory. The non-repeating and non-reversal quantum walks, introduced by Proctor et al, are both interconnected since the non-repeating walk is obtained when the coin used for the non-reversal one is permuted [3]. The latter refers to a walk whereby the state cannot move back onto the position where it has just been before whereas the non-repeating walk cannot move in the same direction which it previously moved. These have applications in organic chemistry, especially for a process known as polymerisation. After careful analysis of these discrete time quantum walks, we carry out an in-depth study of the open quantum walk by Attal et al [4]. It is the quantum version of a classical Markov chain but whereby the states are represented by density matrices. Lastly, we explore the possibility of designing an open quantum self-avoiding walk. REFERENCES [1] Machida et al, arXiv: quant-ph /1307.6288v2 [2] Camilleri et al, doi:10.1038/srep04791 [3] Proctor et al, arXiv: quant-ph /1303.1966v4 [4] Attal et al, J Stat Phys (2012) 147:832–852

106

P35

PYRIDINYL(BENZOAZOLE) Cu(II) AND Zn(II) METAL COMPLEXES: SYNTHESIS AND APPLICATION AS A CATALYST IN POLYMERIZATION OF

LACTIDES AND Ԑ-CARPOLACTONES

Thembisile Zaca


Supervised by Dr Stephen Ojwach Biodegradable polymers such as polyesters are particularly attractive and most used in surgical and pharmaceutical applications [1]. They are traditionally synthesized by ring opening polymerization (ROP) of cyclic esters through coordination-insertion pathway involving a metal alkoxide catalyst [2]. A large number of metal complexes of various types have been extensively investigated as catalysts/initiators for the ROP of heterocyclic monomers [3]. Reactions of compounds 2-(3-pyridyl)-1H-benzimidazole (L1), 2-(2-pyridyl)-1-benzothiazole (L2) and 2-(2-pyridyl)-1H-benzimidazole (L3) with zinc(II) and copper(II) acetates produced the corresponding complexes; [Zn(L1)2(OAc)4)] (C1), [Cu(L1)2(OAc)4] (C2), [Zn(L2)(OAc)2)] (C3), [Cu(L2)(OAc)2)] (C4), [Zn(L3)2(OAc)2)] (C5)] and [Cu(L3)2(OAc)2)] (C6) in quantitative yields. Also the reaction of 2-(2-pyridyl)-1H-benzimidazole (L3) and 2-(3-pyridyl)-1H-benzimidazole (L1) with benzoic acid and zinc(II) acetate produced complexes: [Zn(L3)(Obz)2)] (C7) and [Zn(L1)(Obz)2)] (C8) in high yields. Solid state structures of complexes C2 and C6 have been confirmed by single crystal X-ray crystallography. C2 is a bimetallic complex in which L1 adopts a monodentate binding mode through the pyridyl nitrogen atom while C6 is a monometallic containing two L2 ligands binding in a bidentate fashion (Fig. 1). All the complexes effectively polymerized both D,L-Lactide and ε-caprolactone to produce low molecular weight polyesters (Fig. 1). Both the ligand structure and metal centre influenced the catalytic activities of the complexes. Generally zinc(II) complexes were more active than the corresponding copper(II) complexes and complexes of the benzoimidazole ligands were the most active.

O

O

O

O

CH3

CH3

n

C1-C8

O

OCH3

CH3O

OHOH

Figure 1: Complexes used in the polymerization reactions REFERENCES [1] Dechy-Cabaret, O., B. Martin-Vaca, and D. Bourissou. Chem. Rev., 2004, 104, 6147-6176. [2] Silvernail, C.M., et al.. Inorg. Chem, 2007, 46, 6565-6574. [3] Ning, Y., et al.. Organometallics, 2008, 27, 5632-5640.

107

P36

STUDYING THE EVOLUTION OF COLD GAS IN GALAXIES: LARGE ABSORPTION LINE SURVEY WITH MEERKAT

Ayanda Zungu


Supervised by Professor Jonathan Sievers

The interstellar medium of a galaxy consists of the gas and dust distributed between the stars. The main tool to study the atomic hydrogen in the interstellar medium, is the atomic hydrogen 21-cm spin-flip transition, which traces the main constituent and allows us to extract detailed physical conditions in the gas, such as its temperature and dynamical motions. This absorption line is of great importance for studying the rotation and ISM physics in the Milky Way and external galaxies. It is known in the local Universe that the star formation is closely linked to the cold gas content. However little is known about the physical conditions of the cold gas in high redshift galaxies. In our survey we want to study the properties of the cold gas and star formation at high redshift galaxies. We will use the 21-cm absorption line since it indicates the presence of cold gas to measure the physical properties of the galaxies. We will search for 21-cm absorption line towards the quasar sight lines passing through the disks of nearby galaxies.

108

P37

EFFECTS OF OLEANOLIC ACID ON SMALL INTESTINE MORPHOLOGY AND ENZYMES OF GLUTAMINE METABOLISM IN DIABETIC RATS

Murtala Isah Bindawa


Supervised by Dr. B. Masola The small intestine (SI) is the main site for food absorption and hence critical in metabolic disorders that involve energy balance such as diabetes and obesity. Changes in the metabolism of important metabolites in the SI have drawn attention for the understanding of the pathology of diabetes. The aim of this study is to assess the effects of a known hypoglycemic plants-derived compound oleanolic acid (OA) on some enzymes of glutamine metabolism, the main energy metabolite of the SI, in diabetic rats. Diabetes was induced in Male Sprague Dawley rats by intraperitoneal injection of 60 mg/kg streptozotocin. After one week following induction of diabetes, different groups of the diabetic rats were treated with 80 mg/kg body weight OA, 4 IU/kg bw insulin or a combination. An untreated diabetic group served as a control. Similar groups of non-diabetic rats were also included in the study with an untreated non diabetic group serving as their control. After 2 weeks of treatment, all the animals were euthanized and the small intestine was differently processed for histological and enzymatic studies. The results indicated significant (p<0.05) increase in the weight and length of the SI in the diabetic and non-diabetic treated compared to the normal rats. Morphometric data also showed increased muscular layer thickness, villi length, and number of goblet cells per villus of the SI of diabetic rats compared to the non-diabetic rats. Our results suggest that treatment with OA increases these parameters independent of diabetes. Furthermore, the activities of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were significantly (p<0.05) elevated in non-treated diabetic animals. The treatment of these animals with OA, insulin or a combination of the two ameliorated the increase in ALT and AST activity. Glutamate dehydrogenase activity was elevated (>100%) in all diabetic groups and OA treatment increased GDH activity in the diabetic group while insulin lowered it. Oleanolic acid appeared to have an effect on the intestinal enzymes of glutamine metabolism which may suggest an additional mechanism of its anti-hyperglycaemic action.

109

P38

CRITICAL OVERVIEW OF SEM PREPARATION TECHNIQUES FOR SEED ARILS FROM Strelitzia nicolai

Depika Dwarka


Supervised by Prof Himansu Baijnath For electron microscopy, sample preparation is crucial, the critical concern being that the specimen prepared be an accurate representation of the natural sample [1]. Frequently, delicate plant material which is prepared by the conventional SEM techniques which incorporate chemical fixation, ethanol dehydration, critical-point drying and sputter coating, cause the specimen to shrink and dehydrate extensively to a degree that it looks nothing like the native sample [2]. Sample shrinking has also been noted in delicate animal tissue [3]. The seed aril from Strelitzia nicolai is an example of such delicate material. S. nicolai, is an indigenous plant of South Africa, normally known as the White Bird of Paradise. The delicate appendages (seed arils) if not prepared suitably can alter image quality drastically as well as introduce artifacts [4]. This study evaluates six biological sample-preparation methodologies for imaging the ultrastructure of seed arils from S. nicolai. The six methods examined in this study are 1) Fresh samples viewed in the VP SEM, 2) cryo-fixed and freeze dried for 24 hours, 3) cryo-fixed and freeze dried for 48 hours, 4) chemical fixation using a solution of formalin:acetic acid:alcohol (FAA), 5) chemical fixation using glutaraldehyde (GA) and 6) cryo-SEM (cryo-fixed and viewed on a cold stage at low kV). Fresh samples were subjected to the different preparation procedures and viewed under the SEM. Preparation methodologies were evaluated based on the resultant sample and image quality and reduced potential for artifacts. The arils that had undergone preparation techniques 1 to 5 appear to have collapsed and/or shrunk. These methods employed may reduce artefacts but no method yet can make certain an artefact-free specimen. From our investigation of preparation methodologies for a delicate aril tissue we conclude that the cyro-SEM preparation technique result in the best image quality because of its preservation of the seed aril tissue as close to its natural state as possible. It also has the added advantage of being less time consuming than the other methods. The only disadvantage is the cost involvement. There is no general method for preparing plant tissue for SEM. Plants vary in their tissue characteristics and are relatively difficult to preserve in their original form as compared to animal or insect tissues. Specific preparation procedure needs to be developed and tested for the specific plant part needed to be examined. REFERENCES [1] Boyde A, Boyde S. Further studies of specimen volume changes during processing for SEM: including some plant tissue. Scan Electron Microsc1980, II:117–124 [2] Parsons E, Bole B, Hall DJ, Thomas DE. A comparative survey of techniques for preparing plant surfaces for the scanning electron microscope. J Microsc 1974, 101(1):59–75 [3] Talbot MJ and White RG. Methanol fixation of plant tissue for Scanning Electron Microscopy improves preservation of tissue morphology and dimension. Plant Methods 2013, 9:36 [4] Boyde A, Maconnachie E. Volume changes during preparation of mouse embryonic tissue for scanning electron microscopy. Scanning 1979, 2:149–163.

110

P39

EXPERIMENTAL INVESTIGATION OF AEOLIAN-VIBRATIONAL LOADS ON COMPOSITE INSULATORS

Kabwit Alain Ntambwe

[email protected] School of Mechanical Engineering Supervised by Richard C. Loubser

This paper reports on the experimental evaluation of the relationship between mechanical loads and bending amplitudes of overhead transmission lines (OHTL) caused by wind induced Aeolian vibrations. These loads may have an influence on the long-term performance of insulators which are still under investigation. The methods proposed here are the swept sine test and the bending amplitude test. By selecting the resonance frequencies in the range of 7-25Hz, the peak-to-peak mechanical loads caused by the vibrating conductors on the insulator were measured by a force transducer while a displacement transducer was measuring in the range of 0.1 to 1.0 mm, the peak-to-peak bending amplitude of the conductor. The dynamical loads caused by two ACSR Aluminum Conductors Steel-Reinforced, i.e. Tern 45Al. /7St. and Pelican 18Al. /1St. were collected as a function of the bending amplitude. A comparative study between different clamp configurations was done at four conductor tensile on levels (15-30%UTS with 5% of increment) for both conductors.

111

P40

INTEGRATED CONTROL OF FUSARIUM HEAD BLIGHT OF WHEAT

Zandile Mngadi [email protected]

School of Agricultural, Earth and Environmental Sciences Supervised by Dr Kwasi Sackey Yobo and Prof Mark Laing

Fusarium head blight (FHB) caused by Fusarium graminearum is a devastating disease of wheat worldwide. This disease causes significant yield losses and reduces grain quality. Eight Bacillus and 16 yeast spp. isolated from the phylloplane of maize and wheat plants together with two Trichoderma formulations (Trichoderma harzianum kd and Trichoderma harzianum 77) were tested against the head blight pathogen F. graminearum Isolate F.32 in in vitro and in vivo studies. The eight Bacillus isolates and the two Trichoderma formulations inhibited F. graminearum F.32 in vitro on Potato Dextrose Agar (PDA) by 20-49% and 24-30%, respectively. Bacillus Isolate B7 significantly (p = 0.047) reduced FHB severity by 16% compared to control treatment on Day 22 post pathogen inoculation (ppi) under greenhouse conditions. None of the two Trichoderma formulations was effective in reducing FHB severity under greenhouse conditions. Four yeast isolates tested under greenhouse conditions were also ineffective in reducing FHB severity. The efficacy of three dosages of granulated (1.5 g, 3.0 g, 4.5 g) and liquid (200 ppm, 300 ppm and 600 ppm) potassium silicate (KSi) were tested under greenhouse conditions against Fusarium graminearum. Granulated KSi (3 g and/ 4.5g) reduced FHB severity by 49-58% compared to control treatment on Day 12 ppi. However, none of the KSi dosage was effective in reducing FHB severity after Day 12 ppi. A combination of the granulated (1.5 g) KSi and the two Trichoderma formulations tested under greenhouse conditions was ineffective in reducing FHB severity on wheat heads. There is still a need to search for better and innovative methods to manage this disease

112

P41

CHARACTERIZATION AND PROCESSING OF FAECAL SLUDGE IN THE LAB SCALE LADEPA MACHINE

Mirara Simon


Supervised by Professor Chris Buckley

After the creation of the eThekwini municipality in 1999, over 60 000 ventilated improved pit (VIP) latrines were inherited from the incorporated local entities. In 2009, the municipality set out to empty over 35 000 VIP latrines, which were already full. One of the challenges from this operation was the disposal of the sludge in an environmentally safe way. The initial idea was to dispose of the sludge in wastewater treatment plants but this caused overloading of the treatment plant and so the municipality had to seek an alternative. This led to the concept of the Latrine Dehydration and Pasteurization (LaDePa) machine. This machine is used to process the emptied sludge into dry, pasteurized, pellets, which can be used as a soil conditioner or fertilizer, or which could be combusted as a fuel. The LaDePa machine uses a screw extruder to form “spaghetti-like” pellets, which are subsequently dried and pasteurised by means of medium infrared (MIR) radiation lamps. However, the phenomenological process occurring in machine and the level of drying and pasteurisation have not been accurately determined. It is therefore necessary to carry out an experimental study on representative conditions to those encountered in the LaDePa. This study is therefore based on the small scale LaDePa at the Pollution Research Group (PRG), which is a replica of the full scale LaDePa at eThekwini municipality. A small-scale LaDePa machine is used to study the drying and pasteurisation of faecal sludge. This unit has been installed in the Pollution Research Group (PRG) laboratory. It is a replica of the Pilot plant located in Tongaat with a size reduction of approximately 10:1. The LaDePa machine is composed of two main sections: the extrusion section and drying section, drying, and pasteurisation one. The latter section is composed of a porous steel belt, two medium infrared (MIR) radiators, two vacuum chutes and a discharge hopper. While in operation, pellets formed from faecal sludge extrusion are deposited on the belt then conveyed into the heating zone where they are exposed to thermal radiation emitted by the two successive infrared lamps so that they may be dried. The pellets are finally discharged at the chute for collection. Two vacuum chutes, placed in the belt under its horizontal tracking, facilitate the flow of air and evaporation of moisture out of the dying section, thus enhancing the drying process. The parameters investigated include the drying temperature, the residence time in the LaDePa and the airflow rate around the pellets. This investigation allows determining the influence of these parameters on the pellet characteristics after processing. These includes: - moisture content, volatile solid and ash content in order to characterize drying efficiency; nitrogen, potassium, phosphorous and sulphur content in order to determine the viability of the dried pellets for agriculture use; ascaris eggs content in order to determine the pasteurization efficiency of the process; the calorific value in order to determine the viability of the dried pellets as a biofuel.

113

P42

DYNAMICAL MASS ESTIMATES OF SUNYAEV-ZEL'DOVICH EFFECT SELECTED GALAXY CLUSTERS IN THE MILLENNIUM GAS SIMULATIONS

Nhlakanipho Kwazi Mthembu


Supervised by Dr Matt Hilton

The Atacama Cosmology Telescope (ACT) has assembled a sample of massive galaxy clusters selected via the redshift-independent Sunyaev-Zel'dovich (SZ) effect. To use clusters to measure cosmological parameters, we need to calibrate the relationship between SZ signal and cluster mass (the quantity predicted by models of structure formation). Mass can be measured using the line of sight velocity dispersion of galaxies; however depending on the type of galaxies selected, such measurements may be subject to biases. We investigate this issue using simulated cluster and galaxy catalogues produced by the Millennium Gas project. We aim to devise an optimal observing strategy for calibrating the dynamical mass - SZ-signal scaling relation using future SALT observations. We use the Millennium Gas simulations to determine how many member galaxies in each cluster we need to observe, and how many clusters in total we need to observe, in order to determine the calibration of the scaling relation to a given level of accuracy. We will investigate the possibility of stacking the clusters in bins of SZ signal in order to measure the scaling relation – this has the advantage of averaging out over substructure present in clusters, which is a source of bias in dynamical mass measurements of individual clusters. We also investigate the effect of selecting different galaxy tracers (by varying the magnitude limit such that brighter members are prioritized) on the resulting dynamical mass measurements to check for biases (since we are working with simulations, we know what the true mass should be).

114

P43

THE LEVELS OF SELECTED METALS AND PAHs IN LAKE MZINGAZI AND QUBHU LAKE

Shirveen Sewpersad

[email protected] School of Chemistry and Physics Supervised by Dr Letitia Pillay

Richards Bay is located on the north east coast of South Africa. The area is home to a large industrial sector. The municipality uses four freshwater lakes as natural reservoirs, serving both domestic and industrial needs of the city and its surrounds, as well as being sites of recreation and conservation. Two of the lakes in question are Lake Mzingazi and Qubhu Lake. Lake Mzingazi is situated in the heart of suburban Richards Bay and serves as a freshwater source to the city, a water treatment facility is located on the west bank of the lake.1 The primary method for recharge is via groundwater,2 several streams also feed the lake from the north. The lake drains into the Richards Bay Harbor to the south. Qubhu Lake is situated south of Richards Bay in a more rural setting. The lake's catchment is to the South, and is fed by a number of small rivers. Qubhu Lake drains into the ocean via a stream located northwest of the lake. The Qubhu Lake water treatment works, situated on the lakes southern bank.3 The stresses imposed on these lakes are varied and the continued health of each system is essential for a sustainable water provision. The levels of heavy metals and PAH’s are used as an indicator of the current health of each lake. The aim of this project was to determine the levels of metals and PAHs within each lake and contrast them as well as identifying sources of contamination if any. This study has to date determined the concentrations of a number of metals present in the sediments of the two study lakes and it was found that both Cr and Cd were above regulatory guideline values. The 16 EPA Polycyclic Aromatic Hydrocarbons of concern were also extracted and quantified within each lake and their probable sources were determined using concentration ratios. REFERENCES [1] Mathenjwa, C. M. (2006). Master of Public Health, University of Kwazulu-Natal; [2] Germishuyse, T. (1999). Master of Science, University of Zululand, KwaDlangezwa; [3] Cyrus, D. P., & Martin, T. J. (1988). Distribution and abundance of the benthos in the sediments of Lake Cubhu: a freshwater coastal lake in Zululand South Africa. Journal of the Limnological Society of Southern Africa, 14(2), 93-101. [4] Crone TJ, Tolstoy M. 2010 Oct. Magnitude of the 2010 Gulf of Mexico oil leak. Science 330(6004):634.

115

P44

DEVELOPMENT OF AN IN VITRO HUMAN GASTROINTESTINAL TRACT FOR THE DETERMINATION OF ORAL BIOACCESSIBILITY OF POLYBROMINATED

DIPHENYL ETHERS IN CONTAMINATED E-WASTE SITES

Ovokeroye Abafe [email protected]

School of Chemistry and Physics Supervised by Professor Bice Martincigh

The Unified Bioaccessibility Method (UBM) and the Fed Organic Estimations human Simulation Test (FOREhST) have been modified for measuring human oral bioaccessibility of polybrominated diphenyl ethers (PBDEs) in indoor dusts of known contaminated sites. The simulated in vitro gastrointestinal tract protocol used four compartments: saliva, gastric, duodenal and bile phases, to mimick the human gastrointestinal tract (GIT) in order to determine the oral bioaccessibility of eight environmentally relevant PBDE congeners. The analytical protocols involved GIT extractions followed by methanolic potassium hydroxide saponification (for the FOREhST protocol). Liquid-liquid extractions were employed for the recovery of PBDEs from the supernatants of the GIT fluid extracts; whence ultrasonic-assisted extraction was employed for the determination of residual PBDEs in the matrix and for the total PBDE determination in dust samples. Silica gel column chromatography was applied for the purification of sample extracts prior to gas chromatographic-mass spectrometric determinations of PBDEs. Factors, such as pH, incubation time, presence of food components, and dust-to-solution chemistry, responsible for the oral bioaccessiblities of PBDEs were optimized in this study. A mass balance exercise was carried out to determine the percentage recovery of PBDEs in a standard reference material (SRM 2585) and in contaminated dust samples following the two in vitro GIT methods. The percentage recovery of PBDEs in SRM 2585 ranged from 34.3-91.5 % and 42.4-94.0 % for the FOREhST and UBM protocols respectively; and 60.8-103.1 % in contaminated samples following FOREhST protocols. Higher % bioaccessible fractions (%BAF) in the range of 11.5-104.5 % PBDE were obtained with the FOREhST (fed) protocol compared with 9.5-27.9 % PBDEs in the UBM (unfed) protocol. No significant differences were obtained for the %BAF of PBDEs in SRM 2585 and contaminated sites for examination by the same protocol. However, there were observed differences in the %BAF of PBDEs between the two protocols for both SRM 2585 and contaminated site samples. A positive correlation

was observed for the %BAF of the eight BDE congeners and their respective log Kow partition coefficients in the UBM protocol. The result of the present study is indicative of the need to reconsider legislation on PBDEs, particularly for BDE-209 whose usage is still allowed in a variety of personal, household and industrial products. This study has significant application for the development of Brownfield remediation of contaminated sites.

116

P45 DIGITAL CONTROL OF LIGHT

Nombuso Majola


Supervised by Dr. Naven Chetty and Dr. Angela Dudley The objective of this research was to put forward innovative ways in which digital holography technology can be applied in controlling laser light. The ability to control and manipulate a laser beam has become an extremely desirable feature because it enables the improvement of the efficiency and quality of a number of applications. Methods of controlling light make use of optical components to change the properties of a light beam according to the function of that optical element; therefore, a particular arrangement of optical elements in a system controls light in a certain way. Technological advancements in the in the field of optics have developed a versatile device called a spatial light modulator (SLM), which is a novel instrument that employs computer generated holographic patterns (or phase masks) to modulate the amplitude and /or phase of a laser beam and can perform a function of a number of optical elements. This research presents novel optical set-ups based on the phase-only liquid crystal spatial light modulator (LC-SLM) for generating, controlling and exploring different laser beam patterns. The research contains three main sections, the first one is Holographic beam shaping, where a Gaussian beam was reshaped using a SLM to produce Vortex, Bessel or Laguerre-Gaussian beam. These beams were found to agree with theoretically generated beams. In the second section, we produce off- axis laser beams by constructing coherent superpositions of Gaussian and vortex modes and then use two measurement techniques, peak intensity ratio and modal decomposition technique, to obtain the constituent components of these fields. In the last section, we investigate the propagation dynamics of Vortex and Laguerre-Gaussian beams by using a SLM to digitally propagate these beams in free space, and then performing measurements on the far field intensity pattern. The results show that the Laguerre-Gaussian beam suffers more spreading and beam distortion compared to the vortex beam in free space propagation.

117

P46

FORWARD OSMOSIS OF URINE

Albert Muzhingi [email protected]

School of Chemical Engineering Supervised by Chris Buckley

Improved sanitation, in which sustainable waste treatment and nutrient recovery are emphasised, is necessary in developing countries where people practice open defecation due to lack of adequate sanitation facilities. It is estimated that some 2.5 billion people - two thirds of whom live in Asia, and a quarter in sub-Saharan Africa - still use unimproved sanitation facilities. The lack of proper sanitation is a threat to human health and well-being. The Bill and Melinda Gates Foundation (BMGF) has championed the drive towards enabling universal access to sustainable sanitation services by radically supporting the development of new sanitation technologies and markets for new sanitation products and services. In the ‘Reinvent the Toilet Challenge’ program from The BMGF, membrane filtration is a promising technology to obtain water for reuse and valuable nutrients for use in agriculture from urine. In this context, forward osmosis is an attractive alternative, as it capitalises on the natural phenomenon of osmosis, resulting in a lower energy requirement to drive the process compared to the other desalination technologies. This emerging technology, which is still under development and has limited applications, has been applied by NASA for the reuse of waste water in advanced life support system for space applications. Very limited work has been done on the desalination of urine using forward osmosis. The proposed research will characterise the partitioning of urine by forward osmosis using Ammonium Bicarbonate as the draw solution. Experiments are carried out in a laboratory-scale rig from which water fluxes and water recovery through the membrane are determined. By carrying out physical and chemical analysis of the feed and draw solution, the rejection of salts, organic molecules and particles by the membrane can be measured. The fouling of the membrane after use and cleaning is also characterized. The results will be used to produce a simple in-put out-put model suitable for evaluating different flow sheets and mass balances for the design of a forward osmosis facility in a reinvented toilet. In this project, only stored urine will be used due to its stability compared to fresh urine. The separation of water from the diluted draw solution will not be investigated in this project.

118

P47

MODELLING OF HYDROGEN PRODUCTION FROM SYNTHETIC WASTEWATER AS A FUNCTION OF HYDRAULIC RETENTION TIME AND

ORGANIC SUBSTRATE CONCENTRATION

Nolubabalo Ndaliso [email protected]

School of Life Sciences(Microbiology) Supervised by Professor Stephan Schmidt

This work models and optimizes biohydrogen production from synthetic wastewater subjected to different hydraulic retention time (HRT) and glucose substrate concentration. The central composite design was used to generate thirteen fermentation experiments with varied input parameters of HRT and substrate concentration, in the range of 1 to 3 and 2.24 to 34.76 for HRT and glucose concentration respectively. The hydrogen yields from these experiments were used to develop a quadratic model relating hydrogen production pattern to input parameters. A coefficient of determination (R2) value of 0.73 was obtained, thus the model could explain 73% of the variability on the observed data. The developed model predicted an optimum hydrogen production of 86.29ml with an HRT and glucose concentration of 2 days and 30g/L respectively. The validation experiment gave 106.75ml of H2. A preliminary scale up was carried out in 13L continuous stirred tank bioreactor (CSTB). A pick of hydrogen fraction of 49.15 % was obtained at the 17th hour and a cumulative H2 of 2525.56 ml was achieved corresponding to a yield of 270.52ml/g of sugar concentration. Fermentative hydrogen production can be improved from synthetic wastewater and its optimum operational input parameters generated by the model design.

119

P48

RUNS OF HOMOZYGOSITY IN SWAKARA SHEEP

Masoko Malesa [email protected]

School of Life Sciences Supervised by Mr. Edgar Dzomba and Dr. FC Muchadeyi

Swakara sheep experience a subvital factor that affects their production performance, which is thought to be due to the negative results of inbreeding. Runs of homozygosity are long stretches of DNA fragments that are homozygous and occur as a result of parents transmitting similar haplotypes to their offspring due to shared ancestry. A large contributor to occurrence of these runs is inbreeding. This study aims to identify runs of homozygosity in Swakara sheep of Namibia using high-throughput SNP genotyping technology. Genomic DNA was extracted from blood and hair of 96 grey, black & white Swakara. SNP genotyping was done using the Ovine SNP50 beadchip. Genotype calling at each SNP loci was done in GenomeStudio. Plink v.1.7 was used to assess quality of 54 241 SNPs in each indidividual: low genotyping rate > 0.01, SNPs failing > 0.1 missingness test, MAF > 0.01 and HWE > 0.0001. A total of 43 851 SNPs were available for analyses. Ovine aries genome browser v.3.1 and Ensembl were used to determine associated biological functions of SNPs located within ROH segments. Inbreeding coefficient F average indicated high levels of inbreeding in the black subpopulation and low F average in grey. Thirty-seven unique ROH regions were found across the genome spanning between 3190.68 – 6343.68 kb. ROHs were identified on chromosomes 1, 2, 7, 9, 10 and 20. ROH1 was common between 10 individuals, whose SNP1 is associated with TG and SLA proteins. ROH 8 and 9 were the least common found betweeen 2 individuals. ROH 4 and ROH 8 were only present in white individuals, the SNPs pinning these regions have no associated functions. ROH 7 had 2 subvital individuals and a grey, SNP1 of this region is associated with DPYD gene associated with glycogen debranching enzyme.

120

P49

PHOTOCHEMICAL SYNTHESIS OF LAMIVUDINE DERIVATIVES

Lerato Mollo

[email protected] School of chemistry and physics

Supervised by Prof. Bice Martincigh Photochemistry occurs when light energy is absorbed, producing an excited molecular state. This excitation allows for chemical reactions which cannot take place within traditional ground state chemistry such as photoisomerisation, photocycloaddition or photocyclisation [1]. Lamivudine, commercially known as epivir® is a nucleoside reverse transcriptase inhibitor (NRTIs) used clinically to treat HIV infected-patients. Globally, over 40 million people are infected with the Human Immunodeficiency Virus (HIV), which causes Acquired Immunodeficiency Syndrome (AIDS). This research focuses on the organic synthesis of a novel derivative of Lamivudine (i.e. to increase cellular permeability) by utilizing green chemistry methods such as photochemistry. These derivatives will be amalgamated within nanocarrier systems for in vivo drug delivery. The application of these nanocarrier systems will result in therapeutic efficacy and allow increased drug safety [2]. The carbonyl chromophore exhibits an n → π* excited state, therefore hydrogen abstraction and addition to double bonds are characteristic reactions [3]. We suspect that intramolecular photoreduction takes place, whereby the carbonyl abstracts a hydrogen from the γ-position (-NH2).

S

O

OH

N

NO

NH2

N

HNHO

NH

hv

UVB (315-280 nm)

S

O

OH REFERENCES [1] Liu, S. Kokot, Will, G. Journal of Photochemistry and Photobiology C: Photochemistry Reviews, 2009, 10, 159–172. [2] Sosnik, A; Chiappetta, D.A; Carcaboso, A.M. Journal of Controlled Release, 2009, 138, 2-15. [3] Pischel, U and Nau, W.M. Photochemistry and Photobiology Science, 2002, 1, 141–147.

121

P50

USING JVLA TO REMOVE CMB FOREROUNDS

Onkabetse Sengate [email protected]

College of Agriculture,Engineering and Science Supervised by Prof Jonathan Sievers

The Cosmic Microwave Background (CMB) is the radiation that fills the universe left over from the Big Bang. CMB is an important tool in cosmology as it holds within it the structure of the early universe. The dusty star-forming (DSFGs) galaxies are the main challenging foreground on small scales for the CMB and limit our understanding of cosmology through the CMB. For this project the aim is to try to remove this DSFGs. The radio-far Infra-red correlation means that the low-frequency JVLA data may be able remove the most problematic small-scale CMB foreground very cheaply. We analyze 1.4GHz Jansky Very Large Array (JVLA) data , produce maps and cross-correlate the JVLA data with ACT Maps. If we get a signal in the cross-correlation, we can use it to remove DSFGs from small patch of ACT data. From there we can look if this technique can succeed on improving cosmological constraints from the CMB over larger area were surveyed. For this talk, I will present analysis of JVLA data which is the first part of this project. This include removal of RFI, making maps of On The Fly mode (OTF) JVLA data and removal of bright sources.

122

P51

CAN RUMEN FILL BE PREDICTED USING ARTIFICIAL NEURAL NETWORK?

Rasheed Adebayo [email protected]

School of Agriculture, Engineering and Earth Sciences Supervised by Professor Ignatius Nsahlai

This study seeks to develop a predictive model for simulating the fill of the rumen. Rumen fill has complex dynamic behaviour that takes advantage of both animal and diet factors. This study used 19 sources of data on rumen fill. Data comprised 140 treatment means (78 cattle and 62 sheep),each of which rumen fill was measured by complete manual evacuation through fistulas or slaughtering. Variables collected as predictors of rumen fills (RFD; in kg DM) were: specie/type (SPT), age, physiology state (PHY), live weight (LW), mature body weight (MBW), housing system (MGT), time delay following meal termination (TD), dietary characteristics viz; crude protein (CP), neutral detergent fibre (NDF), acid detergent fibre (ADF) and non-fibre non-protein carbohydrate (CHO). Decisions to terminate feeding activity or to begin feeding affected rumen fill and it appears that artificial neural network can lend a hand during simulation. Artificial neural network (ANN) is a mathematical representation of the neurological functioning of the brain and its usage is new in Animal Sciences. Data were separated into two: for learning (80%) and for validation (20%). The ANN model used for predicting rumen fill was a committee of five networks with a topology of 11 input layers, 6-10 neurons, and 1 output layer (11-(6-10)-1 structured on a multilayer perceptron. Training could explain 83% of the variation in rumen fill (R2 = 0.83). However, for the validation, the relationship between observed and predicted could explain 92% of the variation (R2 = 0.92). Input sensitivity analysis showed 95.36%, 69.4%, 55.25%, and 50.57% for mature body weight, physiological state, crude protein and age, respectively. Validation ended up with a 5.6% prediction error for rumen fill. Manual rumen evacuation is a worthy technique to explore species variation and ANN model for predicting rumen fill with a low prediction error, which appears efficient to simulate fill and or intake in field situations.

123

P52 IMPROVING NETWORK INTRUSION DETECTION USING HONEYPOT

SENSORS AND DATA MINING TECHNIQUES

Tyrone Naidoo [email protected] School of Engineering

Supervised by Prof. J. R. Tapamo and Mr. Andre McDonald In recent years, there has been a rapid increase in network connectivity and Internet usage, resulting in a rise in network intrusions, which places personal information at greater risk. Network Intrusion Detection Systems (NIDS) monitor network traffic to identify unauthorized use, misuse and abuse of computer systems. Firewalls and other security mechanisms are no longer sufficient enough to protect against threats. NIDS are necessary as they act as a second line of defence. NIDS are either signature-based or anomaly-based. The former is more accurate; but cannot detect novel attacks. While the latter produces higher False Positive Rates (FPRs), but can detect novel intrusions. Various implementation techniques are mentioned in [1]. However, these suffer from the shortfalls mentioned above. To improve performance, Machine Learning techniques, specifically Unsupervised Learning techniques, have been investigated [2]. This is also due to a lack of labelled network data. Portnoy [3] performs intrusion detection on unlabelled data using single link clustering. Although decent results are achieved, the algorithm used is dependent on the order of the data points in the dataset and only considers the distance metric when clustering instances. It is hypothesized that clustering based NIDS can be improved by considering the densities between instances in a dataset. In this work Squared-Loss Mutual Information Clustering (SMIC) is considered. SMIC has the advantages of being computationally more efficient and numerically stable versus Mutual Information Clustering, and has been applied successfully in several problem domains [4]. The SMIC algorithm was applied to the KDD Cup 1999 dataset, in addition to K-Means and the clustering algorithm used in [3]. Preliminary results indicate that SMIC works well in clustering large-scale attacks, but poorly performs when used in smaller-scale intrusions. Future work consists of incorporating Honeypot technology into the NIDS system. Honeypots are decoy systems whose sole purpose is to be attacked, in order to gather vital information on the intrusion [5]. Honeypots provide the ability to label attack data and build on the shortfalls of IDS’s. It is hypothesized that the inclusion of honeypot data will ease the burden of recognizing smaller-scale attack clusters, thereby boosting the performance of the system. REFERENCES [1] Biermann, Elmarie, Elsabe Cloete, and Lucas M. Venter. "A comparison of intrusion detection systems." Computers & Security 20.8 (2001): 676-683. [2] Tsai, Chih-Fong, et al. "Intrusion detection by machine learning: A review." Expert Systems with Applications 36.10 (2009): 11994-12000. [3] Portnoy, Leonid. "Intrusion detection with unlabeled data using clustering." (2000). [4] Sugiyama, Masashi, et al. "On information-maximization clustering: Tuning parameter selection and analytic solution." Proceedings of the 28th International Conference on Machine Learning (ICML-11). 2011. [5] Provos, Niels, and Thorsten Holz. Virtual honeypots: from botnet tracking to intrusion detection. Pearson Education, 2007.

124

P53

IDENTIFICATION AND QUANTIFICATION OF CHELIDONIC ACID AND OTHER LIGANDS WITH POTENTIAL FOR NI UPTAKE IN THE HYPERACCUMULATOR,

BERKHEYA CODDII

Chrisanne Naicker [email protected]

School of Chemistry & Physics Supervised by Dr Letitia Pillay

Berkheya coddii is a known nickel hyperaccumulator, a plant that is able to take up high levels of Ni (< 37 000 mg kg -1) without exhibiting toxic effects. It grows in serpentine soil and is endemic to the Barberton Region, Mpumulanga Province, South Africa. One of the key factors governing hyperaccumulators is the mechanism of uptake. This study investigates the uptake mechanism of B. coddii. Plants and soil from this region were collected for analysis and uptake studies (Ni spiking). A characterisation of amino and organic acids, both commonly associated with uptake in hyperaccumulators, was carried out using a range of chromatographic techniques namely, reverse phase-high performance liquid chromatography (RP-HPLC) and liquid chromatography-mass spectrometry (LC-MS). Amino acid analysis results showed a high proline concentration (12 400 mg kg-1) in younger leaves of B. coddii, and organic acid results showed high levels of ascorbic acid (2100 mg kg-1) present in the stem, indicating a stress response to high levels of Ni. Analysis carried out on B. coddii, using methods of size exclusion chromatography (SEC), high resolution-mass spectrometry (HR-MS) and HPLC indicated that the ligand responsible for Ni uptake is the organic acid, chelidonic acid. This study has shown that a leaf-water extract contains chelidonic acid in a 3:1 molar ratio to Ni. Nickel uptake studies were performed to further investigate the relationship between Ni and chelidonic acid. Upon treatment of B. coddii with soluble Ni the concentrations of Ni and chelidonic acid increased. This resulted in an increase of the molar ratio between chelidonic acid and Ni to 6.76:1. This finding has significant impact on the use of B. coddii as a phytoremediator.

125

P54

ANTIMICROBIAL ACTIVITY OF NEW RUTHENIUM(II) AMINE COMPLEX SALTS, [(η5-C5H5)Ru(CO)2L]BF4 (L = RNH2)

Eunice Nyawade


Supervised by Professor Holger Friedric Bacteria rapidly develop resistance to drugs in current clinical use as well as new drugs based upon analogues of known scaffolds. Bacterial resistance to antimicrobial drugs is a significant threat to humans worldwide [1] and therefore, requires urgent intervention. The increased rate of bacterial resistance and need to eradicate the bacteria has triggered increased interest in the development of new classes of antimicrobial agents [2] that may not be as susceptible to the bacterial mechanisms of resistance developed against the current range of drugs. Ruthenium complexes provide a rich platform for the design of antimicrobial agents, allowing for choice between different ruthenium oxidation states, ligands and coordination geometries. Ruthenium containing drugs are of low toxicity partly due to the ability of ruthenium to mimic the binding of iron to biomolecules thus exploiting the mechanisms that the body has evolved for non-toxic transport of iron [3]. Ruthenium complexes of the type, [(η5-C5H5)Ru(CO)2L]BF4 (L = C6H5CH2NH2, C6H5CH(CH3)NH2, NH2CH2(C6H4)OCH3, NH2CH2C6H4CN, p-Aminosalicylic acid and pyrazinamide), have been synthesized and characterized by Infrared and NMR spectroscopy, elemental analysis and X-ray crystallography. The crystal structures of the complexes feature a “pseudo-octahedral three-legged piano stool” structure in which the ruthenium centre is coordinated through a sigma bond to the amine N atom and two carbonyl ligands at the base of the stool and the cyclopentadienyl ring in the apex of the stool. Antimicrobial susceptibility testing was performed for the complexes and the neat ligands against selected drug-resistant and drug-susceptible Gram-positive and Gram-negative bacteria. The compounds demonstrated good potential antimicrobial activities, with the ruthenium complexes displaying the best activity against a number of the bacterial strains tested. REFERENCE [1] H.W. Boucher, G.H. Talbot, J.S. Bradley, J.E. Edwards, D. Gilbert, L.B. Rice, M. Scheld, B. Spellberg, J. Bartlett, Clin. Infect. Dis. 48 (2009) 1. [2] U. Theuretzbacher, Curr. Opin. Pharmacol. 11 (2011) 433. [3] C.S. Allardyce, P.J. Dyson, Plat. Met. Rev. 45 (2001) 62.

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SUITABILITY OF SELECTED METHODS FOR REARING Cotesia sesamiae CAMERON (HYMENOPTERA: BRACONIDAE) AND EFFECT OF ODOUR ON

HOST ACCEPTANCE

Caroline Okoth [email protected]

School of Life Sciences Supervised by Prof. Des Conlong, Dr. Andreas Jürgens and Dr. Teun Dekker

Sesamia calamistis Hampson is one of the stemborers reducing sugarcane,maize and sorghum yields in South Africa. It is, however, successfully attacked by a braconid parasitoid, Cotesia sesamiae Cameron, within these habitats. Successful stemborer parasitoids are known to rely on frass from their host insect to provide short-range cues that aid them in host location. In the sugarcane agro-ecosystem, even though this indigenous parasitoid has kept this stemborer’s population under control over the years, little is known about its performance, host acceptance and attractiveness to frass from sugarcane-fed S. calamistis. To this end, the current study investigated an improved technique for laboratory rearing of C. sesamiae parasitoid, host acceptance of its host insect stage and effect of odour on attractiveness of stemborer frass to the parasitoid. Two methods were investigated to improve the laboratory rearing of C. sesamiae; hand-sting and mass exposure. More hosts were parasitized in the former method than the latter. However, development time, sex ratio, host mortality and parasitoid (immature stage) mortality were not significantly different between the two tested methods. When the data were further analysed, it was observed that host acceptance declined when the hosts (larvae) were left to feed on sugarcane pieces for more than 48 h after inoculation from artificial diet. To ascertain if this was brought about by the effect of odour change over time, larvae were left to feed for 1, 2, 4, 6, 8 and 10 days before exposure to parasitoids. Hosts acceptance and stinging time using hosts removed from sugarcane pieces after being allowed to feed for the number of days stated above were compared with a control (hosts washed in distilled water). Shorter stinging time and higher host acceptance were observed at days 2 and 10. This finding shows that parasitoid attraction as measured through stinging time and hosts accepted varied with the time larvae spent feeding on sugarcane. To test whether the parasitoids response in the aforementioned assays was tactile or odour mediated, olfactometer bioassays were completed using a Y-tube. The arm in which frass odour was presented to the parasitoids was most attractive, compared to the arms with odour from uninfested sugarcane pieces and the control. This suggests that besides visual and gustatory cues, odour was mediating attraction of C. sesamiae to frass produced by S. calamistis feeding on sugarcane, thus enabling the parasitoid to locate and accept (parasitize) its host. Identification of the actual volatile organic compounds (VOCs) that are attractive to C. sesamiae from infested sugarcane genotypes is on-going. This study will be used as a model to study VOCs that could attract natural enemies to Eldana saccharina Walker, the most important sugarcane pest in South Africa. Furthermore, these could be incorporated into the habitat management approach for managing E. saccharina in the sugarcane agro-ecosystem.

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RISK FACTORS AND SPATIAL VARIATION OF HERPES SIMPLEX-2 VIRUS IN KENYA

Elphas Luchemo


Prof Henry Mwambi and Dr. Oscar Ngesa Herpes Simplex Virus-Type 2 (HSV-2) still remains a neglected disease in many parts of the world, especially in Africa. This is evident by the low publicity and few testing centres that are accorded to the disease. The purpose of this work is to determine risk factors of this diseases and asses its spatial variation in Kenya. A fully Bayesian approach is used in the analysis. The Bayesian approach smooths the rate in a county by borrowing strength from its neighbours. The method is applied on the data consisting of 7415 women aged between 15-64 years sampled during the Kenya Aids indicator Survey, 2007. From the analysis, education, age, age at first sex, perceived risk of HIV, place of residence, marital status and number of days travelled and spent away, were significantly associated with HSV-2. High risk counties were located close to the Lake Victoria region. Smoothed maps for HSV-2 risk were produced together with their corresponding 95% credible intervals. The county HSV-2 risk maps can be used for monitoring and surveillance by policy makers to identify high risk counties. Furthermore, they can be used to develop HSV-2 prevention and treatment strategies that suit the communities living in those areas, based on their varying social-economic practices.

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AUTOMATIC LUNG SEGMENTATION USING GRAPH CUT OPTIMIZATION

Oluwakorede Oluyide [email protected]

School of Mathematics, Statistics and Computer Science Supervised by Prof Serestina Viriri and Prof Jules-Raymond Tapamo

The goal of segmentation in medical imaging is to partition an image into anatomical regions such as bone, muscle, blood vessel and fat. Lung segmentation is a preprocessing step for lung parenchyma density analysis [1] and airway tree analysis [2]. Computed Tomography (CT) is the modality of choice for Lung imaging. Present day scanners acquire large amounts of data which need to be analyzed accurately and in short periods of time and computer automated techniques have found to be invaluable in image analysis. Lung segmentation, however, is a non-trivial task given that CT images are prone to noise and artifacts caused by the data acquisition and limited resolution in image formation, resulting in the similarity of range of pixel intensities between the anatomical region of interest and pixels of other regions in the image. In this work, the segmentation problem is formulated as a binary labeling problem and an energy minimization technique is employed to solve it. Graph Cut [3] is a powerful energy minimization technique which guarantees an exact global optimum solution for a binary labeling problem. Due to the global nature of these algorithms, they capture all regions which have similar properties to the region of interest. To ensure the correct labeling of the lung pixels, an additional constraint is introduced to the energy function. The constraint, called the distance term, penalizes the pixels based on their distance from the region of interest. The algorithm is fully automatic and is split into two parts; the detection of the lung region which provides the distance prior for computing the distance term, and the energy minimization stage which provides the final segmentation. The algorithm was validated on publicly available databases and shows the method achieves a sensitivity of 99.31%, specificity of 99.36% and accuracy of 99.37% which compares favorably with the existing methods in literature. REFERENCES [1] Hedlund, L.W., Anderson, R.F., Goulding, P.L., Beck, J.W., Effmann, E.L., Putman, C.E.: Two methods for isolating the lung area of a CT scan for density information. Radiology 144(2) (1982) 353-357 [2] Aykac, D., Hoan, E., McLennan, G., Reinhardt, J.: Segmentation and analysis of the human airway tree from three-dimensional X-ray CT images. Medical Imaging, IEEE Transactions on. 22(8) (2003) 940-950 [3] Boykov, Y., Jolly, M.P.: Interactive Graph Cuts for Optimal Boundary and Region Segmentation of Objects in N-D Images. In: Computer Vision, 2001. ICCV 2001. Proceedings. Eighth IEEE International Conference on. Volume 1. (2001) 105-112

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GRAVITATIONAL COLLAPSE OF GENERALIZED VAIDYA SPACETIME

Maombi D. Mkenyeleye [email protected]

School of Mathematics, Statistics and Computer Science Supervised by Pro. S. D. Maharaj and Dr. R. Goswami

We study the gravitational collapse of a generalized Vaidya spacetime in the context of the Cosmic Censorship hypothesis. We develop a general mathematical framework to study the conditions on the mass function so that future directed non-spacelike geodesics can terminate at the singularity in the past. Thus our result generalizes earlier works on gravitational collapse of the combinations of Type-I and Type-II matter fields. Our analysis shows transparently that there exist classes of generalized Vaidya mass functions for which the collapse terminates with a locally naked central singularity. We calculate the strength of the singularities to show that they are strong curvature singularities and there can be no extension of spacetime through them.

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PREDICTION OF MESOCARP MOISTURE CONTENT, DRY MATTER AND MESOCARP OIL OF ‘HASS’ AVOCADO USING NIRS

Olaoluwa Olarewaju

[email protected] School of Agriculture Earth and Environmental Science Supervised by Prof Isa Bertling and Dr Lembe Magwaza

Near-infrared (NIR) spectroscopy (NIRS) (FOSS NIRSystem) was evaluated as a non-destructive technique to predict maturity parameters of ‘Hass’ avocado such as percentage mesocarp moisture content (%MMC), percentage dry matter (%DM) and percentage mesocarp oil content (%MO). A total of 150 intact ‘Hass’ avocado fruit were harvested and scanned in reflectance mode of the NIRS in 2013 and 2014 growing season. The acquired spectral data were analysed using principal component analysis (PCA) to identify outliers. A chemometric analytical tool, partial least square (PLS) regression was applied to the spectral data to develop prediction models for each of the parameters. The spectral dataset were grouped into various calibration/training and prediction/test sets which include calibration (60) and prediction (40) sets for the 2013 early season data; calibration (32) and prediction (23) sets for 2014; calibration (2013 dataset (100)) and prediction (2014 dataset (55)); and calibration (85) and prediction datasets (70) dataset encompassing randomly selected samples from the two seasons. NIR calibration and prediction results confirmed that %MMC and the reciprocal value, %DM, having residual predictive deviation (RPD) for prediction of 2.00 and 2.13 respectively were predicted with quantitative analytic potential. The prediction result for %MO indicated that the model with RPD 1.0 was unreliable. The good and fair correlation between spectral data and the maturity parameters confirms the potential of FOSS NIRSystem as a non-destructive tool to evaluate the maturity parameters of ‘Hass’ avocado.

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REACTOR MODEL AND CATALYST PERFORMANCE DATA EVALUATION IN THE 2-STAGE DIRECT COAL LIQUEFACTION PROCESS

Reyna Singh

[email protected] School of Chemical Engineering Supervised by Dr David Lokhat

While petroleum has been the primary feedstock for the production of liquid fuels for decades, it is evident that petroleum reserves are declining and petroleum prices are on the rise. Coal, a solid fossil fuel, is an abundant resource in many countries and represents approximately 70% of the world’s total energy reserves [1]. The cost of converting coal into useful liquid fuel is higher than the cost of refining crude oil; however it is the abundance and hence relative price of the raw coal feedstocks that provides the main incentive to pursue the coal-to-liquid technology [1]. A major shortfall of the direct coal liquefaction process is the lack of literature on the analysis of the liquid product. Temperature control and mass transfer limitations in pilot and lab-scale studies have proven to favour undesirable product types and poor yield. Catalyst expense and performance has also been a concern. As a spawn of the high pressure, high temperature Bergius process, this study presents and compares experimental results and mathematical models of the two-stage direct coal liquefaction process using different catalysts and reactor types. A batch reactor and loop reactor model for the first stage of the process, and a fixed bed reactor model for the second stage of the process were simulated in MATLAB. Experiments were carried-out using magnetite and cobalt-molybdenum (CoMo) on silica for the first and second stages of the processes respectively. Mathematical models were generated using rate data for these catalysts, and for the first stage a comparison was made between iron pentacarbonyl (Fe (CO) 5) and magnetite. The experimentally formed product oil was analysed using Gas-Chromatography Mass-Spectrometry (GCMS) with a deuterated internal standard mixture. A comparison between the first stage catalysts revealed that while Fe (CO) 5 might increase the rate of reaction and favour a slightly higher yield in intermediate products, the production costs and hazards involved in manufacturing this catalyst are a major shortfall in the use of this catalyst. The use of a deuterated internal standard mixture proves useful in identifying compounds in a complex coal-derived liquid. Results generated from the MATLAB simulations for the tubular fixed bed reactor and loop reactors were used as recommendations to address the temperature control and the inefficient mass transfer concerns of the process. REFERENCES [1] Energy Information Administration, 2004.URL: http://www.eia.doe.gov Accessed on: 09 April 2014

http://www.eia.doe.gov/

http://www.eia.doe.gov/

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FORAGING EFFICIENCY OF NGUNI GOATS IN RELATION TO PLANT SPECIES AND SEASONS IN AN ARID SUB-TROPICAL

SAVANNAH, SOUTH AFRICA

Sylvester Werekeh Fomum [email protected]

School of Agriculture, Earth and Environmental Sciences Supervised by Prof. IV Nsahlai

The objectives of this study were: (1) To determine the seasonal and plant species trend of foraging efficiency indexed by browse short term intake rate (IR) of Nguni goats; and (2) To investigate how spinescence, phenology, leaf and shoot morphology, and leaf chemistry will potentially explain the observed trends. The study was carried out in the dry, early rainy and late rainy seasons. Ten plant species were presented to goats individually under shade. Instantaneous intake rate varied amongst species (p< 0.05) and seasons (p< 0.05). Acacia caffra, Acacia robusta and Rhus lancea featured amongst species with the highest IR in all three seasons, Ehretia rigida and Acacia nilotica were consistent as the least efficiently foraged. Gymnosporia buxifolia that was efficiently foraged in the dry season, declined to amongst the least in the early and late rainy seasons. Browses with long shoots were more efficiently foraged relative to those with short shoots (t= -3.2; df= 284.64; p< 0.002). Evergreen plant species yielded higher intake rate compared to deciduous species (t= 2.02; df= 278.01; p< 0.044). Intake rate of spinescent relative to spineless species was not significantly different (p> 0.05) but more bites were cropped from spinescent relative to spineless species (t= 2.80; df= 256.77; p= 0.006). Bite sizes were smaller for spinescent relative to spineless species (t= -3.30; df= 227.4; p= 0.001). There were significant positive correlations of cellulose with IR (r= 0.71; n= 10; p= 0.023), and also with condensed tannins (CT) (r= 0.71; n= 10; p= 0.023) in the dry season. Additionally, cellulose also had a positive correlation with bite size in the same season (r= 0.73; n= 10; p= 0.016). At early rainy season, there was no correlation of intake with any of the plant chemical components, whereas, NDF (r= 0.65; n= 10; p= 0.044), hemicellulose (r= 0.76; n= 10; p= 0.012) and CT (r= 0.68; n= 10; p= 0.032) all correlated positively with browsing time at early rainy season. Regression equations were derived from correlations to model IR and related variables: The following regression equations were derived to model intake rate and some intake rate related variables: (1) intake rate= 0.433 + BSDM (0.081), r2= 0.68, p< 0.05 and BSDM= bite size dry matter; (2) Bite rate= 0.503 –BSDM (0.147), r2= 0.597, p< 0.05 and BSDM= bite size dry matter; (3) Bite size dry matter= 1.713 – BR (4.210), r2= 0.597 ,p< 0.05 and BR= bite rate, and (4) Intake dry matter= 3.804 + BSDM (0.865), r2= 0.607, p< 0.05 and BSDM= bite size dry matter. More bites were cropped from spinescent species to attain the same IR as obtained from spineless species.

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THEORETICAL AND COMPUTER SIMULATION STUDY OF PHASE COEXISTENCE IN BINARY 2D-3D HARD CORE MIXTURES

Owen Daniel Pandaram


Supervised by Dr Giuseppe Pellicane One of the main goals of this research was to study liquid-liquid phase coexistence in systems of nonadditive hard sphere mixtures (NAHSMs) and systems of nonadditive hard disk mixtures (NAHDMs). Many techniques for studying phase separation exist, however the Gibbs Ensemble Monte Carlo (GEMC) method is a versatile and fair approach to study phase separation without the bias deriving from the presence of an interface between the two coexisting phases. Application of the GEMC method to a binary hard sphere/hard disk mixture is no trivial task, as it involves the extension of its algorithm to a system consisting of two different species. In the case of NAHSMs, the focus was on creating some computer simulation benchmarks for existing statistical theories that covered a range of size ratios and non additivity parameters. These benchmarks would also function as a basis to test future theoretical contributions. The application of GEMC to NAHSMs, in order to assess current theories such as the method of the zero of the Residual Multi-Particle Entropy, Integral Equation Theories (IETs), and classical Density Functional Theory (DFT) unveiled that most of them were semi quantitatively accurate as reported in a paper published in J. Chem. Phys. 141, 044508(2014). For NAHDMs, Monte Carlo integration methods were used to find the fifth virial coefficient to help building the virial equation of state together with scaled and modified variants. In order to assess the latter, constant-NVT ensemble Monte Carlo simulations were performed. Finally for a wide range of nonadditive parameters, the GEMC method was applied to this system in order to evaluate phase coexistence and assess the theoretical predictions obtained from the equations of state as we reported in another recently submitted paper to the journal of Physical Chemistry.

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DETERMINING THE MECHANISM OF ACTION FOR DEGLUTATHIONYLATION BY THE GLUTATHIONE/GLUTAREDOXIN (GSH/Grx) SYSTEM USING COMPUTATIONAL AND MATHEMATICAL

MODELS.

Mashamaite Lefentse [email protected]

School of Life Sciences Supervised by Dr. Ché Pillay and Prof. Johann Rohwer

Glutaredoxins (Grxs) are important electron donors found in most living cells and are involved in essential functions such as DNA synthesis, iron metabolism and iron-sulfur cluster assembly. During their catalytic cycles Grxs become oxidized and are reduced by glutathione (GSH) and glutathione reductase which collectively form the GSH/Grx system. Grxs also play a critical role in regulating the glutathionylation/deglutathionylation cycle. Under oxidative stress conditions, proteins may be modified by glutathionylaion, a post-translational regulatory mechanism and Grx activity is imported for restoring the functions of these proteins. Currently the mechanism of Grx activity describing deglutathionylation is not clear as Grxs have been proposed to follow either a mono- or a di-thiol mechanism. Due to differences in these mechanisms; systems biology models are expected to have different structural properties and are likely to produce different behaviours for the same set of input parameters. In vitro data supporting these mechanisms have also displayed discrepancies. For example, a mammalian Grx mutant Grx(C→S) showed activity in a deglutathionylation assay, apparently confirming the monothiol mechanism while, an E. coli Grx showed greater activity than its corresponding mutant. Also, a wild type E. coli Grx showed a sigmoidal pattern for deglutathionylation, implying that two GSH molecules were used in the reduction of Grxs, but other studies reported a linear response with GSH, supporting the monothiol mechanism. Similarly unclear, two substrate kinetics for Grxs have showed both ping-pong and sequential kinetics patterns. Using computational and mathematical models we were able to resolve these discrepancies. Firstly, a mathematical model showed that the relative activity of mutant and wild-type Grxs depended critically on the rate constant for GSH-oxidation and on the GSH concentration used in kinetic assays. To understand the contrasting reciprocal plot kinetics for Grxs, we modified our mathematical model and compared it to the standard ping-pong kinetic expression. Our results showed that a ping-pong pattern was expected with a glutathionylated protein but a sigmoidal pattern would be obtained with increasing GSH concentrations. In addition, kinetic modeling experiments showed that a sequential pattern was obtainable when the reduction of the protein substrate was modelled with reversible kinetics. Finally we showed that the mono- and di- thiol mechanisms, although not identical, may be functionally equivalent, and together with the fitting experiments we showed how deglutathionylation should be described in computational systems biology models.

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COVARIANCE CLUSTERING FOR DIMENSIONALITY REDUCTION IN HYPERSPECTRAL IMAGES

Hannah Adebanjo

[email protected] School of ENGINEERING

Supervised by Prof. J.R. Tapamo Hyperspectral images provide rich spectral information with increased dimension which enables greater discrimination between classes. For effective classification [1], the spectral dimension of images has to be reduced. Methods for dimensionality reduction of hyperspectral images have been proposed in the literature [2]. Dimensionality reduction is an important step in the processing of hyperspectral images as it is said to contain redundant information which are not useful. Effectively reducing the dimension and retaining useful information for further processing is important before classification. In this work, we compute covariance matrix for real hyperspectral images and present the result into k-means clustering for discrimination between classes and classification. This approach will be compared with the correlation clustering [3] [4] approach under different number of clusters and classification results. REFERENCES [1] T. V. Bandos, L. Bruzzone, and G. Camps-Valls, Classification of Hyperspectral Images with Regularized Linear Discriminant Analysis, IEEE Transactions on Geoscience and remote sensing, Vol . 47, No. 3, 2009 [2] Hyperspectral image classification and dimensionality reduction: an orthogonal subspace projection approach, IEEE Transactions on Geoscience and Remote Sensing, Vol. 32, No. 4, 1995. [3] M. Imani and H. Ghassemian, Feature Extraction using Partioning of Feature Space for Hyperspectral Images Classification, Proc. IEEE Conf. Iranian Conference on Intelligent System, 2014. [4] B.-C. Kuo, Correlation Matrix Feature Extraction based on Spectral Clustering, Proc. IEEE WHISPERS, 2012.

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LINKING ULCERATION AND DISCOLOURATION OF THE EQUINE GASTRO-INTESTINAL TRACT TO DIET

Catherine Wiid


Supervised by Dr Marion Young

There are many factors that cause ulceration in horses. The aim of this research was to investigate the linkages between limited gastrointestinal pathophysiology and certain types and amounts of feed. Data were collected from 53 horses that were put down due to mechanical injuries or financial reasons. Zones of the gastro-intestinal tract (GIT) were examined and pH levels were recorded from the same location. Multivariate linear regression was performed to relate Age, Breed, Nutrient density, Body weight and Sex to the incidence and severity of ulceration and discolouration in the gastro intestinal mucosa. There was a significant (P<0.05) difference in the incidence of ulceration in relation to the age and nutrient density levels, with an increase in ulceration of the stomach in older horses, and in horses receiving high concentrate feeds. pH levels in sections of the tract were different, but also altered significantly (P<0.05) by the roughage to concentrate ratio the horses were receiving. Causative factors in GIT pathophysiology can be identified to be nutritional.

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STATE AND PARAMETER ESTIMATION USING THE HYBRID FORMALISM

Humairah Bassa [email protected]

School of Chemistry and Physics Supervised by Prof. Thomas Konrad We consider the problem of tracking the evolution of a single quantum system when the dynamics are not precisely known, via a continuous measurement protocol. We encode the ignorance of dynamical parameters in a classical system which is coupled to an estimate of the quantum state to form a genuine hybrid quantum-classical system. The estimated hybrid state is updated using information obtained from continuous measurements on the quantum system and after a sufficient waiting period faithful state monitoring and parameter estimation is obtained. Numerical simulations are used to demonstrate the convergence of the estimated hybrid state to the true state.

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WOMEN EMPOWERMENT IN AGRICULTURE INDEX - ARE FEMALE SMALLHOLDER IRRIGATION FARMERS IN RURAL LIMPOPO PROVINCE

EMPOWERED?

Vongai Murugani [email protected]

School of Agriculture, Earth and Environmental Sciences Supervised by Dr Joyce Chitja

Agriculture is an important livelihood activity for many rural women who are mostly unemployed. Although they do most of the work, they may not always enjoy the benefits of their work as they may only be implementers of the household head’s wishes. Patriarchy and other rural institutions have largely left rural women disempowered. Empowering women in agriculture could help them to improve their livelihoods and the quality of their households’ lives. Empowerment in this context would take the form of increasing the female farmers’ decision making capacity and agency. The concept of empowerment in agriculture is new and yet important because it focuses on a sector of rural women who may have previously been overlooked. Understanding empowerment is difficult because people define and experience it differently; this makes it difficult to measure. In this study empowerment is assessed across five domains in agriculture; production decision-making and autonomy, access to and control of resource, access to and control of income, leadership and time use satisfaction. Using indicators for these five domains, it is possible to see where women as farmers are empowered and possible areas for intervention. The study was carried out in three communities in rural Limpopo Province and data was collected using an adapted Women’s Empowerment in Agriculture Index (WEAI) questionnaire. Data analysis was carried out in SPSS to determine the empowerment levels of women using a sub-index of the WEAI called the five domains of empowerment (5DE). The results show that there were different levels of empowerment across the five domains in the three communities. Generally women in the communities were more empowered with respect to production and resource access than they were in income and time use satisfaction. This suggests that more work needs to be done to ensure that women can take part in financial decision making in their households and that labour saving initiatives should be considered to give women time to engage in other profitable activities.

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UNDERSTANDING UNCERTAINTY IN RAINFALL FROM REGIONAL CLIMATE MODEL SIMULATIONS: A HYDROLOGICAL PERSPECTIVE

Samuel Kusangaya

[email protected] School of Agriculture, Earth and Environmental Sciences.

Supervised by: Dr Michele L. Warburton, Dr Emma Archer van Garderen, Prof Graham P.W. Jewitt

Precipitation is the main driver of the hydrological cycle. For climate change impact analysis, use of downscaled precipitation, amongst other factors, determines accuracy of modelled runoff. However, precipitation is considerably more difficult to model than temperature, mostly due to its high spatial and temporal variability and its nonlinear nature. Because of rainfall’s high spatial and temporal variability, a key challenge for water resources management then is how to incorporate potentially-significant but highly uncertain rainfall information in modelling potential changes in climate for water resources management in order to support local management decisions. Research undertaken here contributes to understanding and quantification of uncertainties in using downscaled rainfall in hydrological studies. Using the Mgeni catchment as a case study, the occurrence of rainfall, rainfall events and wet dry sequence was analysed for current climate (1961-1999). Number of rain days with daily rainfall >1mm, >5mm, >10mm, >20mm for each of selected 10 climate models was compared to number of observed rain days at 13 rain stations. Results from graphical analysis indicate that on a monthly basis rain days are over estimated for all climate models. Seasonally, the number of rain days was overestimated in autumn and winter and underestimated in summer and spring. The overall conclusion from this study is that the notion that advancement in downscaling, hence improved spatial scale provides a better representation of the climate variables such as rainfall for use in hydrological impact studies still needs more research in southern Africa.

Key Words: uncertainty, climate change, rainfall, regional climate models

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DYNAMICAL MASS ESTIMATES OF SUNYAEV-ZEL'DOVICH EFFECT SELECTED GALAXY CLUSTERS IN THE MILLENNIUM GAS SIMULATIONS

Nhlakanipho Kwazi Mthembu


Supervised by Dr Matt Hilton

The Atacama Cosmology Telescope (ACT) has assembled a sample of massive galaxy clusters selected via the redshift-independent Sunyaev-Zel'dovich (SZ) effect. To use clusters to measure cosmological parameters, we need to calibrate the relationship between SZ signal and cluster mass (the quantity predicted by models of structure formation). Mass can be measured using the line of sight velocity dispersion of galaxies; however depending on the type of galaxies selected, such measurements may be subject to biases. We investigate this issue using simulated cluster and galaxy catalogues produced by the Millennium Gas project. We aim to devise an optimal observing strategy for calibrating the dynamical mass - SZ-signal scaling relation using future SALT observations. We use the Millennium Gas simulations to determine how many member galaxies in each cluster we need to observe, and how many clusters in total we need to observe, in order to determine the calibration of the scaling relation to a given level of accuracy. We will investigate the possibility of stacking the clusters in bins of SZ signal in order to measure the scaling relation – this has the advantage of averaging out over substructure present in clusters, which is a source of bias in dynamical mass measurements of individual clusters. We also investigate the effect of selecting different galaxy tracers (by varying the magnitude limit such that brighter members are prioritized) on the resulting dynamical mass measurements to check for biases (since we are working with simulations, we know what the true mass should be).

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