Science ReporterCurrent- 2013

Ravi P. Agrahari (Science &Technology)

Science Reporter issues (Current-2013)June 2012

- Coal fly ash in agriculture- beneficial or risky ?

July 2012 :-

- Salt tolerant Salicornia

- Journey of milk to the consumer- Probiotics

- Adulteration in milk

August 2012 :-

- Superstar superbugs

September 2012:-

- Mobile phone application

- Polished rice smoothens path to diabetes

October 2012:-

- CSIR@70

- XNA

November 2012:-

- India in Alice experiment

- Gravitational wave observatory

- Silver hut experiment

December 2012:-

- Global dimming

- Nobel Prize in Physics, Medicine and Chemistry

- Silicon life beyond

Conceptual Topics Discussion

• India in Alice experiment• Gravitational wave observatory• XNA • Superabsorbent Polymer (SAP)• Outsmarting the Superbugs• Milk Process • Coal fly ash in agriculture- beneficial or risky ?

India in Alice experiment

Indian scientist are involved in a very existing research program as part of the ALICE experiment at CERN since last two decades. Components of the ALICE detector like he Photon Multiplicity Detector and Muon Spectrometer are products of Indian scientific and industrial excellence. The Quark Gluon Plasma research program at ALICE is on the quest to unearth the physics of deconfinement and vacuum, and to get a glimpse of how matter behaved within a few microseconds after the birth of our Universe.

Our universe began with a Big Bang about 13.7 billion years ago. A few microseconds from the beginning, this hot and dense matter around us is made up of molecules, which are clusters of atoms bound together by electromagnetic forces. The atom consists of a dense central nucleus, made up of protons and neutrons and surrounded by cloud of negatively charged electrons. Inside the protons and neutrons, quarks are bound together by a force known as strong interaction, mediated by the exchange of force carrier particles called gluons.

Universe begin Big Bang│

In first few instant of time (micro second)│

A hot and dense matter form called“Quark- Gluon plasma”

(Hadron is a composite particle of Quark and Gluon)│

Inside proton and neutron, quarks are bound together by a force known as strong interaction, mediated by the exchange of force carrier particles

called gluons.│

The strong interaction is in fact responsible for binding the protons and neutrons together inside the atomic nuclei. There are six types of quarks:

up, down, strange, charm, bottom and top. The up and down quarks make up the protons and neutrons.

Quarks have various intrinsic properties like electric charge, colour charge, mass and spin. Gluons are exchange of photons in the electromagnetic force between two charged particles. Quarks and gluons behave like free particles when they are very close together, but feel much stronger forces if they are separated. This unique properties of quarks and gluons is known as asymptotic freedom. Because of asymptotic freedom quarks are never directly observed in isolation, and are confined within composite particles called hadrons.

The current theory of strong interaction, Quantum Chromo Dynamics (QCD), predicts that at very high temperatures and high energy densities, quarks and gluons are no longer confined inside the hadrons. Instead, they would exist freely in the form of free quarks and gluons, a state called Quark Gluon Plasma. The Quark Gluon Plasma state is relevant to questions about the origin of the universe within the first few microseconds of the birth of the universe, conditions of extremely high temperature and energy density existed and the primordial state of matter was a system of QGP.

Thus, to understand the evolution of our universe during its infancy, we need to create and study the formation of QGP in the laboratory.

This is done by colliding two heavy nuclei (such as gold on gold or lead on lead) together at very high energies. In this collision process, it is possible to compress and heat the colliding nuclei in such a way that their individual protons and neutrons overlap. This creates a region of high energy density. By inducing head on collision of lead nuclei, accelerated by the Large Hadron Collider (LHC) to a speed close to that of light we aim to obtain- albeit over a tiny volume of the size of a nucleus and for an infinitesimally short instant- a QGP state. We then observe this QGP state as it reverts to hadronic matter through expansion and cooling. Probing the hot and dense matter produced in high-energy heavy-ion collisions is one of the major tasks of the experiments at the LHC.

The ALICE (A LARGE ION COLLIDER EXPERIMENT) experiment is devoted to the search and study of QGP in the laboratory. Two other LHC experiments, CMS and ATLAS also have excellent programs for QGP research. We are probing the properties of vacuum, and getting a glimpse of how matter behaved immediately after the Big Bang.

The two major Indian contributions to the ALICE detector systems from India include the Photon Multiplicity Detector (PMD) and Muon Spectrometer. These two detectors have been fully operational and continue to collect data, contributing to the strong physics programme of ALICE.

Gravitational wave observatory

MEGA SCIENCE PROJECT

India will soon be joining a global network of Gravitational Wave Observatories

India is geared to add a new dimension to 21st century astrophysics by settling up a state-of-the-art ‘Gravitational Wave observatory’ (GWO) in collaboration with the United States of America as part of a global network.

The proposal for the $290 million dollar facility is pending approval of the Government of India. The Indian scientists are confident that the union cabinet will soon clear the ‘mega science project’ that involved sanction of Rs. 1260 crores to be spent over the next 15 years (2012- 2027).

The prestigious project, codenamed IndlGO, aims at construction and subsequent fifteen year operation of an advanced interferometric gravitational wave detector in India, called LIGO-India in collaboration with USA’s LIGO laboratory.

LIGO, which stands for the Laser Interferometer Gravitational-Wave Observatory, is a large-scale physics experiment aiming to directly detect gravitational waves, cofounded in 1992. It is sponsored by the National Science Foundation (NSF). At the cost of $365 million (in 2002 USD), it is the largest and most ambitious project ever funded by the NSF.

The international LIGO Scientific Collaboration (LSC) is a growing group of researchers, over 800 individuals at roughly 50 institutions, working to analyze the data from LIGO and other detectors, and working toward more sensitive future detectors. The current spokesperson for the LIGO Scientific Collaboration, re-elected in March 2013, is Louisiana State University Professor of Physics and Astronomy, Gabriela González.

What are Gravitational Waves ?

“Gravitational waves” (GWs) akin to the electro-magnetic waves, have been detected from the Universe. The GWs are emitted by gravitating bodies in motion, such as two ‘black holes’ spiralling towards each other in a binary orbit in the cosmos. Gravitational Waves are extremely difficult to detect, and although they were predicted about one hundred years ago, till today they have not been seen in experiments. There is irrefutable indirect evidence that they do exist-this evidence comes that the compact binary orbit of a pair of stars is shrinking due to the emission of gravitational waves.

(Binary star systems : systems with two stars bound together by their gravity, are actually quite common. While all binary systems orbit their mutual center of gravity, not eclipsing. This actually has more to do with us then it does with the distant star systems. If we view a binary system from the top or bottom, then one star does not pass in front of the other from our perspective and the amount of light we see from a star system does not vary. However, if we are happen to be looking right down the side of a binary system, one stars passage in front of the other can will cause the light from the other star to be blocked, and the amount of light coming in from the binary system will dim. Of course, binary systems are often comprised of two stars of different luminosities. When the brighter of the two stars eclipses the dimmer star, the drop in brightness is small, and we call this the secondary minimum. When the dimmer star eclipses the brighter, the drop is larger, and we call this the primary minimum.)

The experimental discovery of gravitational waves will open an extraordinary new window in astronomy, what is often known as gravitational wave astronomy. Just as astronomers have been studying the universe for centuries using electromagnetic waves, they will in the future be able to study it with gravity waves. Great experiments are currently in progress worldwide, using ‘Gravitational Wave Detectors (GWD), to find gravitational waves.

(Gravitational waves: Violent events, such as the collision of two black holes, are thought to be able to create ripples in space-time known as gravitational waves. The Laser Interferometer Gravitational Wave Observatory is presently searching for the first signs of these tell-tale indicators).

In 1905, Albert Einstein determined that the laws of physics are the same for all non-accelerating observers, and that the speed of light in a vacuum was independent of the motion of all observers. This was the theory of special relativity. It introduced a new framework for all of physics and proposed new concepts of space and time.

Einstein then spent ten years trying to include acceleration in the theory and published his theory of general relativity in 1915. In it, he determined that massive objects cause a distortion in space-time, which is felt as gravity.General relativity is a theory of space and time created by Albert Einstein and published in 1915. The central idea of general relativity is that space and time are two aspects of spacetime, which is curved in the presence of gravity, matter, energy, and momentum. The relationship between these forces is shown in the Einstein Field Equations. One mathematical formula for General relativity is , although there are many more equations.

In general relativity, freefall is inertial motion instead of being at rest on a massive body such as the Earth, as described by the equivalence principle.

General relativity has made many successful predictions. These include: The bending of light as it passes the Sun by twice the Newtonian value for an object travelling at the speed of light. This was confirmed by Eddington in 1919, and the announcement forced scientists to take general relativity seriously.

The perihelion of the planet Mercury advances more than is expected under Newtonian physics. General relativity accounts for the difference between what is seen and what is expected without it.

The gravitational redshift effect, by which the wavelength of light increases as it moves away from a massive object. This was confirmed by the Pound-Rebka experiment.

The Shapiro delay, under which light appears to slow down as it passes close to a massive object. This was first confirmed in the 1960s by space probes headed towards the planet Venus.

Mission

LIGO's mission is to directly observe gravitational waves of cosmic origin. These waves were first predicted by Einstein's general theory of relativity in 1916, when the technology necessary for their detection did not yet exist. Gravitational waves were indirectly suggested to exist when observations were made of the binary pulsar PSR 1913+16, for which the Nobel Prize was awarded to Hulse and Taylor in 1993.

Direct detection of gravitational waves has long been sought. Their discovery would launch a new branch of astronomy to complement electromagnetic telescopes and neutrino observatories.

In August 2002, LIGO began its search for cosmic gravitational waves. Measurable emissions of gravitational waves are expected from binary systems (collisions and coalescences of neutron stars or black holes), supernova of massive stars (which form neutron stars and black holes), accreting neutron stars, rotations of neutron stars with deformed crusts, and the remnants of gravitational radiation created by the birth of the universe.

The observatory may in theory also observe more exotic currently hypothetical phenomena, such as gravitational waves caused by oscillating cosmic strings or colliding domain walls. Since the early 1990s, physicists have believed that technology has evolved to the point where detection of gravitational waves—of significant astrophysical interest—is now possible.

Observatories

LIGO operates two gravitational wave observatories in unison: the LIGO Livingston Observatory in Livingston, Louisiana, and the LIGO Hanford Observatory, on the DOE Hanford Site, located near Richland, Washington. These sites are separated by 3,002 kilometers (1,865 miles). Since gravitational waves are expected to travel at the speed of light, this distance corresponds to a difference in gravitational wave arrival times of up to ten milliseconds.

Through the use of triangulation (triangulation is the process of determining the location of a point by measuring angles to it from known points at either end of a fixed baseline, rather than measuring distances to the point directly), the difference in arrival times can determine the source of the wave in the sky.Each observatory supports an L-shaped ultra high vacuum system, measuring 4 kilometers (2.5 miles) on each side. Up to five interferometers (Interferometry makes use of the principle of superposition to combine waves in a way that will cause the result of their combination to have some meaningful property that is diagnostic of the original state of the waves) can be set up in each vacuum system.

There are two detectors in the USA under LIGO Laboratory while the third one GEO is in Hannover (Germany) now under upgrade with pioneering advanced optical technologies.

An advanced LIGO version of the VIRGO with advanced seismic isolation system is also operational near Pisa in France with US collaboration since May 2007.

A $100- million Large Cryogenic Gravitational Telescope (CGWT), to be ready by 2017, is under construction in an underground Kemijoki mine in Japan as part of the network.

LIGO-India

LIGO-India is a collaborative project proposed by the LIGO Laboratory and the Indian Initiative in Gravitational Observations (IndIGO) to create a world-class gravitational-wave detector in India. The LIGO Laboratory, with permission from the U.S.

National Science Foundation and Advanced LIGO partners from the U.K, Germany and Australia, has offered to provide all of the designs and hardware for one of the two planned Hanford Advanced LIGO detectors to be installed, commissioned, and operated by an Indian team of scientists in a facility to be built in and by India.

The project requires the support and agreement of both governments in addition to the LIGO Laboratory and IndiGO. The project was discussed at a Joint Commission meeting between India and the US in June 2012. In parallel, the proposal was evaluated by LIGO's funding agency, the NSF.

As the basis of the LIGO-India project entails the transfer of one of LIGO's detectors to India, the plan would affect work and scheduling on the Advanced LIGO upgrades already underway.

In August 2012, the U.S. National Science Board approved the LIGO Laboratory's request to modify the scope of Advanced LIGO by not installing the Hanford "H2" interferometer, and to prepare it instead for storage in anticipation of sending it to LIGO-India. In India, the project has been presented to the Department of Atomic Energy and the Department of Science and Technology for approval and funding. Final approval is pending

The IndlGO Consortium Institutions include Chennai Mathematical Institute, IISER-Kolkata, IISER-Pune, IISER-Thiruvananthapuram, IIT-Madras, IIT-Kanpur, IPR, IUCAA-Pune, RRCAT-Indore and University of Delhi.

According to the proposal document, the major funding in the XII Plan is Rs. 650 Crores for the construction of the detector. During the XIII 5-year Plan (2017- 22) the expected expenditure is Rs. 380 Crores, out of which Rs. 280 Crores is for completing the construction and installation of the detector and the remaining Rs. 100 Crores for continuous operation and maintenance.

The XIV Plan will see mature gravitational wave astronomy with the LIGO-India detector. Projected operation cost for continuous operation and maintenance during this period (2022-27) is Rs. 230 crores. Thus, the total projected expenditure for 15 years spanning three plan periods from 2012-2027 is Rs. 1260 Crores.

These have the potential to seed technologies spin-offs in several areas that include ultra-stable and high power lasers, high-tech optics, sensors and vibration isolation platforms, multi-channel control systems, large volume data storage, retrieval computing and fast network communications and quantum technologies for communication.

LIGO-India will be transformational for Indian physics, technology and astronomy and will drive accelerated growth in these areas over decades. The partnership with LIGO moves the gravitational wave detector project to a state of readinessthat would normally take decades to achieve.

For the LIGO-India project, the US and its international partners (UK, Germany and Australia) will contribute complete design and hardware of the detector worth $140 million (650 crores).

XNA(New Twist in Molecular Genetics)

The newly synthesized nucleic acid, Xenonucleic Acid, offers exciting possibilities in scientific

research and understanding the bounds of what it means to be alive.

This thinking changed in a breakthrough in molecular genetics in April 2012 when Vitor Pinheiro and Philip Hollinger and their team at the MRC laboratory of Molecular Biology, Cambridge, UK developed six alternatives polymers called XNAs. These XNA molecules can store genetic information and evolve through natural selection. The discovery forms a turning point in the era of synthetic genetics, which expands the chemistry of life in new uncharted directions.

(Xenonucleic Acid) XNA

This thinking could soon change, synthetic biologists from MRC laboratory under the leadership of Vitor Pinheiro and Philip Hollinger have developed six alternatives polymers called XNAs that can also store genetic information, replicate and evolve like the genetic systems consisting of DNA and RNA. The “X” in XNA stands for “xeno” a latin prefix that means exotic of foreign. Scientist have used this term to indicate the synthetic nature of these molecules- that one of the ingredients typically found in the building blocks that make up RNA and DNA has been replaced by something different from what occurs naturally.

How was XNA synthesized?

Under normal conditions DNA Polymerase is highly specific about the bases it attaches and only selects bases with a deoxyribose sugar so that it assembles DNA, rather than any other nucleic acid. Pinheiro and his team modified the existing enzyme using a genetic engineering technique called compartmentalized self-tagging (or “CST’) and created mutants of this DNA Polymerase so that it prefers to use the building blocks of XNAs with other types of sugars instead of the normal bases for DNA.

He also created an enzyme that could do the reverse – convert XNA into DNA. Of course, no natural enzyme can even begin to do this, so the evolution trick didn’t work in this direction. Instead, Pinheiro used a more brute-force approach: he took a different polymerase, randomly mutated it, and looked for versions that could do the XNA-to-DNA conversion. Eventually, he moulded one.

Pinheiro ended up with enzymes that could copy information between XNA and DNA, with an accuracy of 95 per cent or more. With more work, it should be possible to cut DNA out of the loop altogether, so that XNAs can be directly built from XNAs. If this is possible, Szostak adds, “In the longer run, it may be possible to design and build new forms of life that are based on one or more of these non-natural genetic polymers.”

There are already hints of this. The team has so far managed to copy FANA and FANA, CeNA from CeNA, and even HNA from CeNA. However, all these steps were far less efficient than working through DNA. But Holliger says that there would be few benefits to abandoning the middle-man, because “it’s convenient to go through DNA.”

That’s because all of our genetic technology is geared to our standard nucleic acids. If we moved towards XNA-only experiments, we would also have to tweak our sequencing tools and cloning techniques to match.

Implications of XNA Synthesis

Scientist consider the discovery of XNAs extremely important owing to their far reaching implications and their special properties.

Synthetic life : it is believed that XNAs might, in future, help in the creation of synthetic genetic systems based on alternative chemical platforms, and hence entirely synthetic alternatives novel forms of life that will not require DNA or RNA for functioning.

Origin of Life : some researchers believe that life might have been based on simpler genetic systems before the emergence of RNA and DNA.

Medicine and Therapeutics : generally biomolecules like RNA, DNA, enzymes and antibodies are used as therapeutics, diagnostics and in biosensing applications. But a serious drawback of this technique is the short lifespan of such treatments and the difficult time they have in reaching their therapeutic targets as they are degraded quickly in the stomach. In such a scenario, XNA can be used as a potential therapeutic agent targeting diseased cells as they are more resistant to degradation and biological systems don’t have enzymes evolved enough to digest them.

Exobiology : is the branch of science that is involved with looking for life on other planets. Emergence of XNA as a molecule that can store information, replicate and evolve suggests that DNA and RNA no longer might be the only markers for the search of life and that life forms based on XNA might exist on other planets.

Superabsorbent Polymer (SAP)

SAP are polymers that can absorb and retain extremely large amounts of a liquid relative to their own mass. SAPs are used in diapers as well as to retain water in soil.

Take 2-3 grams of poly acrylic acid sodium salt (sodium polyacrylate) in a 100 ml plastic or glass beaker. Add 20-30 ml of water in to it. Formation of SAP takes place in 10-15 seconds.

Outsmarting the Superbugs

Superbugs have evolved into a serious community health problem. Will be able to conquer the

menace that we have ourselves created through the indiscriminate use of antibiotics ? scientists are

working hard to counter this challenge.

When a person is treated with antibiotics, about 30% is absorbed and the rest passes through the body into the sewage system. Antibiotics are not readily degraded. Ultimately the sewage enters a treatment plant, which encourages the growth of bacteria to digest the sewage. During this process, in the presence of low levels of antibiotics, some bacteria may develop resistance.

Thus, in a large population of bacteria there may be a few that have developed resistance to antibiotics. When an infected person is treated with antibiotics, the susceptible ones perish, leaving behind the resistant ones, which will multiply at the opportune moment. Next time when the same antibiotic is given to the patient, it may not be effective in controlling the infection. When a class of bacteria becomes resistant to a particular drug, the pharmacologist develops a new kind of antibiotic. It takes more than a decade to develop an antibiotic and the bacteria become resistant to even the new drug in due course.

What antibiotics do ?

Antibiotics are designed to block some essential steps in the lifecycle of the bacteria and prevent their growth and survival. These include synthesis of cell wall, folic acid, DNA, RNA and protein. Since many of these processes occur in the host cell (human and animal cells) also, targets chosen are specific to the bacteria, so that the drug may not harm the host cells. For example, unlike human and animal cells, bacterial cells have a thick cell wall. Antibiotics of the class beta-lactams (which includes penicillin) bind and inactivate an enzyme (called ‘penicillin binding protein’ PBP), which is essential for the synthesis of the cell wall. A bacterial cell without a robust cell wall cannot survive.

Folic acid biosynthesis is another example how these tiny bugs defy mighty human efforts. Folic acid is required by both bacteria and humans for the synthesis of nucleic acids and proteins. Unlike humans, bacteria cannot use pre-formed folic acid and synthesize their own folic acid. An important starting compound for the synthesis of folic acid is para aminobenzoic acid (PABA).

Sulphonamides and other sulfa drugs are analogous to PABA and bacteria can not distinguish between the two. These compounds compete with PABA in biochemical reactions. When chosen, they block the synthesis of folic acid and thus the formation of nucleic acids and proteins, killing the bacteria.

An essential step in DNA replication prior to cell division is the unwinding of the double stranded DNA molecule. This is carried out by an enzyme called DNA gyrase. A class of antibiotics known as fluoroquinolones bind to bacterial DNA gyrase and inhibit DNA replication preventing bacterial growth. Rifamycins inhibit RNA synthesis in an analogous manner.

Ribosomes are structures on which protein synthesis takes place. Tetracycline, Erythomycin and similar antibiotics bind to ribosomes to prevent protein synthesis.

He first superbug appeared on the scene less than twenty years after the discovery of the antimicrobial drug. Antibiotic resistance was first observed in Staphylococcus aureus against penicillin in 1947.

Superstar Superbugs :

Bacterial classes like staphylococci, enterococci, pneumococci all have the ability to become superbugs. There are strains of E. Coli resistant to five variants of the drug fluoroquinolone.

The best known superbug is the methicillin (a penicillin class antibiotic) resistant Staphylococci aureus (MRSA). Later strains are reported to have developed resistant to a number of antibiotics like tetracycline, erythromycin, vanomycin, and linezolid. MRSA is commonly found on human skin and mucous membranes. It is easily contacted in places like gym, schools and hospitals. It is quite common in Europe, UK, and USA. According to a report, in 2005 MRSA was responsible for nearly 95,000 cases of serious infection with almost 19,000 hospital-related deaths in United States. MRSA has also been successful in transmitting resistance genes to a completely different species of bacteria- Enterococcus faecalis- making it resistant to vanomycin.

Another bacterium Streptococcus pneumonia- has been a major cause of community acquired infection such as upper respiratory infection, bronchitis, pneumonia, pharyngitis and meningitis. Even though it was once almost eradicated by penicillin. It has now developed significant resistance to penicillin, trimethoprim, sulfamethoxazole, macrolides, tetracyclins and fluoroquinolones and thus has become a major problem.

Another well known superbug that is bothering public health authorities in the developing world is Mycobacterium tuberculosis. It is reported that tuberculosis kills about 1.7 million people around the world, of which three to four lakh deaths occur in India due to the presence of resistant strains like Multi Drug Resistance (MDR-TB) and Extremely Drug Resistance TB (XDR-TB). Now, Hinduja Hospital, Mumbai has reported the isolation of yet another resistant strain known as Totally Drug Resistant TB (TDR-TB), which is found to be resistant to twelve drugs.

Recently a new resistant strain Klebsiella pneumoniae was detected in a Swedish patient of Indian origin.

This produces an enzyme named New Delhi- beta- lactame-1. Which inactivates a broad range of beta- lactam antibiotics.

This gene NDM-1 can spread horizontally and at least twenty strains of bacteria, each resistant to one or many antibiotics, are now known.

Milk Process

The milk goes through several processes that can be termed as “dairy process”. Dairy processing is an industrial operation in which milk components are separated and re-constituted to produce desired milk products. From milking to consumption, milk may undergo a lot of dairy processes depending upon the product desired. Let us look at some of these processes.

Cooling : microorganism growth is prevented by immediately chilling the milk to five degree Celsius or below. At this temperature, milk will retain its freshness for three to four days.

Standardization : if milk has to be sold as buffalo milk, the minimum fat percent should be standardization to 6% for most of the states in India. Milk may be standardized to full cream milk; Toned milk, Double Toned milk etc. Full cream Milk should contain minimum 6.0% fat and 9.0% Solids not fat (SNF) while standardized milk should contain minimum 4.5% fat and 8.5% SNF. Toned Milk and double Toned Milk should contain minimum 3.0% fat and 8.5% SNF and minimum 1.5% fat and 9.0% SNF, respectively.

Pasteurization : Pasteurization kills all pathogens and most of the spoilage type of microorganisms. For this purpose milk is heated to such a time- temperature combination that ensures destruction of even the most heat resistant pathogen. Mycobacterium (TB germ) is the most heat resistant pathogen and it is taken as the index for deciding pasteurization temperature. Pasteurization may be done by two methods – Low temperature Long Time (LTLT) or High Temperature Short Time (HTST). Now a days, the HTST method is mostly used. After Pasteurization, the milk must be immediately cooled down to five degree Celsius or below so that the surviving microorganisms do not multiply further.

Cream Seperation : in cream separation, fat is removed from the milk by passing it through a cream separator in which it is rotated at a very high speed (around 8000 revolutions per minute) in thin films. Milk cream or fat, being lighter (specific gravity 0.9), remains in the centre while the skimmed milk (skim milk contains all the constituent except fat), being heavier (specific gravity 1.036), goes towards the periphery in the cream separator. The separated cream and milk are collected from different outlets provided in the cream separator.

Homogenization : the fat in milk is present in shape of fat globules that are of different sizes. The size may range from 0.1 to 22 microns and generally it is from 2-8 microns. Homogenization is the process in which fat globules are broken down mechanically to a size of about one micron. Homogenization is generally used in reconstitution of milk and fat rich products like ice cream, condensed milk, sterilised flavoured milk etc. Homogenised milk does not stick to the container and gives a viscous appearance and rich mouth taste.

Standardization : some bacterial spore may not get destroyed even through boiling of milk. They are destroyed through sterilization, which is the process of heating milk to 120 degree C for 30 seconds or 150 degree C for 2-3 seconds so that a shelf life of six months of milk at room temperature is ensured.

Adulteration in Milk

The most common adulteration is water. This is added to increase the volume of milk during loose milk distribution. The second category of adulterants is the one that are added to mask the adulteration of water in milk. These are added to increase the SNF level. The number of such adulterants is very large. The most common are starch, matlodextrins, sugar, salt, urea and a lot more.

In addition, traders may also add other chemicals to milk. When milk is transported to farther places for distribution, the bacteria in milk deteriorate it producing lactic acid. This lactic acid destabilizes the proteins in milk and when such milk is heated, it gets coagulated. To prevent such curdling, traders and alkaline neutralizers like caustic soda and sodium bicarbonate so that the developed acidity is neutralised and milk does not curdle on heating.

Another class of additives to milk may be preservatives. These are substances that have bacteriostatic or bactriocidal effects and prevent the growth of microorganism. This enhances, the shelf life of milk. But addition of these preservatives is illegal and such substances are harmful for human health. The most common preservatives are hydrogen peroxide and formalin.

Coal fly ash in agriculture- beneficial or risky ?

India has a vast coal reserve of 211 billion tonnes making coal one of the most extensively used fossil fuels for generating power. However ash content of forty to fifty percent in Indian coal presents an inherent problem of ash disposal.

The ministry of power, Government of India extimates that 1800 million tonnes of coal use every year leading to generation of 600 million tonnes of fly ash by 2031- 2032.

Since fly ash is a fine powder, it could cause respiratory problems when inhaled. It may also lower agricultural yields by settling on leaves and crops. When added to soil indiscriminately, toxic metals such as chromium, silicon, mercury, lead and arsenic contained in fly ash could enter the food chain harming animals and humans. Fly ash occurs as very fine particles, having an average diameter of less than 10 µm, low to medium bulk density, high surface area and very light texture.

Fly ash in agriculture

- Improves permeability status of soil - Improves fertility status of soil/agriculture yield. - Improves soil textural properties and soil aeration. - Reduces soil bulk density and crust and compact formation - Improves water holding capacity/porosity. - Makes favourable and optimum soil pH for crops. - Provides several micronutrients such as Mo, B, Mn, Fe, Zn, Cu, etc. - Source of many macronutrients like Mg, S, K, P, Ca, etc. - Alternative for gypsum for reclamation of sodic soils and lime for reclamation of acidic soils. - Improves soil microbial activities in combination with other organic amendments.

Fly ash risk in agriculture

- Uptake and accumulation of toxic heavy metals by crop plant. - Fatal effect on humans and cattle due to consumption of heavy metal contaminated crops. - Ground water pollution due to heavy metal percolation down to earth. - Higher doses of FA in agriculture field may cause soil infertility. - The radiochemical pollution present in FA.