SCIENCE & TECHNOLOGY

Plants as a viable energy source
By Shirish Joshi

American scientists, like Dr Z. Conrad Zhang who led a research team on the subject at the Institute for Interfacial Catalysis, have discovered the most effective method yet to convert glucose, found in plants like corn and soyabeans grown worldwide and nature’s most abundant sugar, to hydroxymethylfurfural (HFM).

Obesity can be caught like a cold!
By Steve Connor
Obesity can be caught like a cold, according to a laboratory study showing that a common infectious virus can turn human cells into fatty tissue, scientists have found. It is well established that the human adenovirus-36 causes respiratory and eye infections but now scientists have discovered that it can also transform adult stem cells found under the skin into the fat cells of adipose tissue.

Prof Yash Pal

Prof Yash Pal

PROF YASH PAL
THIS UNIVERSE
I have heard about the suggestion of some scientists that by mining the abundant quantities of Helium-3 on the surface of moon we can produce large quantities of energy very cheaply. What are the facts and how much of it is sheer nonsense?
One thing is certainly true. If some one gave us an enormous amount of helium-3, then through interaction of that helium with deuterons, nuclei of heavy hydrogen which are fairly abundant in water, we could produce enormous amounts of energy.

Asteroid collision killed off dinosaurs
By Christopher Lee

A cosmic traffic accident in the asteroid belt between Mars and Jupiter 160 million years ago appears to have been the beginning of the end for the dinosaurs. That was when two large rocks — one 106 miles across, the other 37 miles — slammed together, creating a cluster of asteroid fragments known as the Baptistina family that included 300 pieces larger than 6 miles in diameter.

Scientists pinpoint memory neurons
By Denise Gellene

Tracing the circuitry of memory in the brain, scientists have found that neurons activated during traumatic experiences also store the memory of those events. The discovery, reported this week in the journal Science, moved researchers a step closer to understanding how information is learned and remembered — a scientific journey that could lead to better treatments for people with impaired memories.

 


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Plants as a viable energy source
By Shirish Joshi

American scientists, like Dr Z. Conrad Zhang who led a research team on the subject at the Institute for Interfacial Catalysis, have discovered the most effective method yet to convert glucose, found in plants like corn and soyabeans grown worldwide and nature’s most abundant sugar, to hydroxymethylfurfural (HFM).

HFM is a chemical that can be broken down into components to make plastics in common use today. It is an organic compound derived from carbohydrates such as glucose and fructose and is viewed as a promising starting material for petroleum-based chemicals made currently.

Scientists have been trying all these days to replace crude oil as the root source for fuels, plastics and scores of other industrial and household chemicals with inexpensive, non-polluting renewable plant matter.

Dr Zhang and his colleagues have now directly converted sugars common in nature to an alternative source for those products that make oil so valuable, with very little of the residual impurities that have made the quest so daunting all these years.

However, getting a commercially viable yield of HMF from glucose has been very challenging.

In addition to low yield until now, the processes always generated many different by-products like levulinic acid, making product purification expensive and non-competitive with petroleum-based chemicals.

They were able to achieve HMF yields upward of 70 per cent from glucose and nearly 90 per cent from fructose, while leaving only traces of other impurities. The chemistry at work remains largely a mystery and now they are trying to unravel its secrets.

Another team led by Dr James Dumesic, a chemical engineer from the University of Wisconsin, US, has also found a new, efficient and potentially low-cost way to turn fructose into HMF.

A third team led by Dr Geoffrey Coates, working at the Cornell University, US, has recently succeeded in making polylimonene carbonate, a plastic with many of the characteristics of polystyrene, from carbon monoxide and limonene extracted from oranges.

The exciting aspect of this work is that from completely renewable resources, they were able to make a plastic with very nice, useful qualities.

The key to Coates’ successes has been his group’s discovery of a new class of catalysts. According to Dr Coates these catalysts are several times more active than the currently used commercial catalysts.

In the long term, switching over to plants, as the raw material for plastics production, is probably unavoidable, if oil is as finite a resource as is currently believed.

Using plants as a source for making chemicals currently becomes competitive when the oil price is at or above $ 55 per barrel. And scientists feel that within the next few years plants could become competitive even with oil at $40-45 per barrel.

Research along the above lines should be taken up in India at the earliest as otherwise the country’s dependence on crude oil, indigenous or imported, will go up more and more every day. India is a very large producer of corn soybeans as well as oranges.

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Obesity can be caught like a cold!
By Steve Connor

Obesity can be caught like a cold, according to a laboratory study showing that a common infectious virus can turn human cells into fatty tissue, scientists have found. It is well established that the human adenovirus-36 causes respiratory and eye infections but now scientists have discovered that it can also transform adult stem cells found under the skin into the fat cells of adipose tissue.

The scientists also found that there is a specific gene in the virus that appears to control this fatty transformation, which they observed when human stem cells grown in the laboratory became infected.

The findings, presented last month to the annual meeting of the American Chemical Society, suggest that the growing global epidemic of obesity may involve more than a lack of exercise and a love of high-calorie food.

“We’re not saying that a virus is the only cause of obesity, but this study provides stronger evidence that some obesity cases may involve viral infections,” said Magdalena Pasarica of Louisiana State University in Baton Rouge.

“Not all infected people will develop obesity. We would ultimately like to identify the underlying factors that predispose some obese people to develop this virus and eventually to find a way to treat it,” Dr Pasarica said.

Previous research on animals suggested that adenovirus-36, along with two related viruses known as Ad-37 and Ad-5, can trigger overweight and obesity. Another study found a high prevalence of adenovirus in overweight people - some 30 per cent of obese people were infected with Ad-36 compared with 11 per cent of lean people.

This led to suggestions that respiratory viruses may play an important role in triggering the tendency towards obesity in susceptible people with the sort of sedentary lifestyle that favours putting on weight.

The latest study appears to support these claims at the cellular level by looking at how the virus interacts with human stem cells growing outside the body in laboratory cultures.

Dr Pasarica obtained the stem cells from fatty tissue obtained from a broad cross-section of patients who had undergone liposuction. She exposed half of the stem cells to Ad-36, while the other half were not exposed to the virus.

After about a week of growing in the laboratory, most of the virus-infected adult stem cells developed into fat cells whereas the non-infected stem cells did not, Dr Pasarica told the American Chemical Society.

“A common virus appears to target stem cells in humans to generate more and bigger fat cells,” Dr Pasarica said.

“The results are clear. Ad-36 prompts adult, fat-derived stem cells to convert to pre-fat cells, rather than other cell types. Furthermore, these fat cells accumulate lipids - fats - at an increased rate,” she said.

“We conclude that human adenovirus Ad-36 increases the number of fat cells and increases their fat content in humans, which might contribute to the development of obesity,” she told the meeting.

The spread of obesity around the developed world is one of the fastest growing epidemics today. However, the idea of it being even partly the result of viral infections is contentious - most experts put it down to a change in diet and lifestyle.

— The Independent

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PROF YASH PAL
THIS UNIVERSE

I have heard about the suggestion of some scientists that by mining the abundant quantities of Helium-3 on the surface of moon we can produce large quantities of energy very cheaply. What are the facts and how much of it is sheer nonsense?

One thing is certainly true. If some one gave us an enormous amount of helium-3, then through interaction of that helium with deuterons, nuclei of heavy hydrogen which are fairly abundant in water, we could produce enormous amounts of energy. In this reaction the products would be ordinary helium, namely helium-4 and a proton and nothing else – except for a lot of energy.

This fusion reaction involves transfer of one neutron from deuterium to He-3, turning it to ordinary helium (He-4), and releasing the left over proton from deuterium. No radioactive elements would be produced and most of the energy would come out as a charged beam of protons. Because of their charge these protons can be contained using electric and magnetic fields and their energy converted into electrical energy with high degree of efficiency.

One cannot imagine a cleaner way of producing electrical energy. (However, some contamination would occur because mixing of He-3 and deuterons would also produce other reactions that would produce neutrons). It is claimed that if the supply of He-3 were enough we could solve the energy problem of the planet once for all. (Mere 3 grams of He-3 would be enough to run a 1000 Mega-Watt reactor for half an hour, assuming 100% conversion efficiency).

Heavy water is not that scarce. It forms 1 part in 7000 of all the oceans of the earth from which it can be separated without too much hassle. We already produce hundreds of tons of heavy water for our reactors. The problem is that the natural abundance of He-3 is extremely low (< .000137%). So where can we get sufficient amount of this valuable gas?

Origin of He-3

It is believed that stars, while going through their energy producing fusion reactions, synthesized most of the chemical elements below Iron. The heavier elements were produced in further evolution of stars resulting in supernova explosions, spreading their cooked material into space. This material formed the stuff of which the later stars and their planetary systems were constituted.

It became clear therefore that those elements and isotopes that form important fuels for the fusion reactions within stars could not be produced within the stars. They would only be consumed. Therefore an idea developed that such low mass elements might be synthesized in early phases of evolution of the Universe. Detailed calculations had to take into account the changing rates and character of fusion reactions during the fast expansion of the Universe in the first two or three minutes of its life!

But let us come back to question of energy generation using He-3.So far the enterprise of mining for this gas has not been pursued because of its low abundance. It is interesting that the primary source available to scientists is a byproduct of the weapons program of the two major powers. One of the ingredients used in hydrogen bombs is Tritium (H-3); this nucleus has one proton and two neutrons.

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Asteroid collision killed off dinosaurs
By Christopher Lee

A cosmic traffic accident in the asteroid belt between Mars and Jupiter 160 million years ago appears to have been the beginning of the end for the dinosaurs.

That was when two large rocks — one 106 miles across, the other 37 miles — slammed together, creating a cluster of asteroid fragments known as the Baptistina family that included 300 pieces larger than 6 miles in diameter.

The orbits of these fragments were slowly changed by thermal forces as they absorbed sunlight and then radiated away the heat, a process that gradually drove about 20 percent of the largest rocks out of the asteroid belt, researchers reported last week in Nature. One large piece went on to strike Earth 65 million years ago in what is now the Yucatan Peninsula in Mexico, creating the Chicxulub crater in a gigantic explosion that triggered the mass extinction of the dinosaurs.

The strike was not an isolated incident but part of a broader twofold increase in big asteroid impacts on the moon and Earth over the past 100 million to 150 million years. Using computer simulations to trace the breakup, researchers calculated that other large fragments probably created the Tycho crater on the moon and many large craters on Venus and Mars.

“We are in the tail end of this shower now,” said co-author William F. Bottke of the Southwest Research Institute in Colorado. “Our simulations suggest that about 20 percent of the present-day, near-Earth asteroid population can be traced back to the Baptistina family.”

— LA Times-Washington Post

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Scientists pinpoint memory neurons
By Denise Gellene

Tracing the circuitry of memory in the brain, scientists have found that neurons activated during traumatic experiences also store the memory of those events.

The discovery, reported this week in the journal Science, moved researchers a step closer to understanding how information is learned and remembered — a scientific journey that could lead to better treatments for people with impaired memories.

Scientists at Scripps Research Institute in San Diego t racked brain activity in genetically engineered mice whose neurons turned on a specific gene, known as LAC, when a memory was formed, and a second gene, ZIF, when the memory was recalled.

Michael S. Fanselow, a University of California, Los Angeles, psychologist who studies memory and was not involved in the study, called the findings important.

“We’ve never before been able to look at a single neuron that was active during learning and memory retrieval,” he said. “And they were able to show the number of neurons is important in terms of the strength of the memory.”

— LA Times-Washington Post



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