Science and Technology

Carbon Aerogel

Zhejiang University in China in May 2013 announced that the team of scientists produced an ultra-light substance known as carbon aerogel, which has the density of 0.16 milligrams per cubic centimeters.
The scientists claimed that this was the lightest material ever produced by anyone. The carbon aerogel is made of granite as well as the carbon nanotubes which can absorb around 900 times its own body weight. The lead scientist, Professor Gao Chao explained that carbon aerogel was structure-wise, just like carbon sponge. When the aerogel with the size of a mug was put on Setaria, then even the grass would not bend. Professor Gao Chao also explained that the carbon aerogel can provide effective solutions to major problems like cleaning oil spills as well as pollution control.

What are Aerogels?

Aerogels are primarily produced by extraction of liquid component of the gel through supercritical drying. This enables liquid to slowly dry off without having an impact on solid matrix. This means that the solid matrix in gel does not collapse from the capillary action, which would take place with conventional evaporation. First aerogels were manufactured from the silica gels. Samuel Stephens Kistler in 1931 produced aerogels based on tin dioxide, chromia and alumina. First carbon aerogels were developed in late 1980s.

Quantum  Biology Mimicked in Lab

For the first time scientists have engineered a series of molecules that show quantum effects similar to that observed in the light-harvesting complexes. Greg Engel’s groups in University of Chicago have been able to both understand as well as mimic the efficient mechanism of light transfer happening in plants. Aside from other benefits, this would lead to the production of artificial energy-transfer devices which could use the mechanism efficiently.
Photosynthetic antennae are arrays of proteins and chlorophyll which transfer absorbed light energy to the reaction centres where light energy is converted to chemical energy. This enhances the efficiency of light transfer compared to the process when light is absorbed directly by the reaction centres themselves. The secret of the efficiency of the transfer process lies in quantum electronic coherence that stretches over some femto seconds (a femto second is a millionth of a billionth of a second). When there is coherence, energy from the incoming photon can simultaneously explore every possible cholorophyll route from the protein’s surface to the reaction centre at its core and then settle for the shortest route. Compare this with the time and energy wasted if the photon had to sequentially try out every path before reaching the reaction centre. Thus the efficiency of the process is increased manifold.
The researchers have engineered a series of molecules that show quantum effects similar to that observed in the light-harvesting complexes. Biological light-harvesting systems are so complex that they obscure the design principles involved. However, the model systems engineered by the group are simpler yet manage to capture the physics involved, according to the report published on April 18 in Science Express. The main actor in this is a dye-like material called fluorescein. The researchers modified fluorescein and linked parts of these together rigidly to form a series of compounds. The resulting molecules were able to mimic the behaviour of light-harvesting centres in plants that use photosynthesis, especially the coherences which persists for over tens of femto seconds.

Bio-inspired Peptides for Gene Delivery

Seeking to overcome the problem of suitable delivery mechanism for gene therapy, scientists at CSIR-Centre for Cellular and Molecular Biology (CCMB) have designed peptide-based delivery platforms for tumour targeting which holds the potential for cancer treatment. The scientists have developed recombinant peptides through bacterial fermentation to bind DNA or small interfering RNA (siRNA) or short hairpin RNA (shRNA) and deliver them into cells to target tumours. Since DNA, siRNA and shRNA are negatively-charged, they require carriers like recombinant proteins, said Dr. Vijaya Gopal, senior principal scientist, who along with her colleagues designed novel peptide-based carriers to ferry biological macromolecules into cancer cells.
Lack of suitable delivery platforms is impeding progress in gene therapy, she says. While stressing that the main concerns in gene therapy are toxicity and safety, she points out that peptide and lipid-based polymers are two main types of non-viral carriers. Although the suppression of tumours in animal studies has been successful, further investigations are essential to validate the efficacy in preclinical situation, she adds.

Focus Areas

One of the focus areas in the future will be to design peptide-based modules to target brain tumours by crossing the blood-brain barrier. According to CCMB Director, Dr. Ch. Mohan Rao, complete understanding of the physiochemical properties of nanoparticles as delivery systems, including peptides, is essential to improve clinical usefulness. Targeted drug delivery would be less toxic as it attacks only the diseased cells and spares the normal cells, he says. Drugs may be packaged into small particles made from biodegradable synthetic polymers or designed peptides. Scientists at CCMB are attempting to study and develop such systems. “In addition to delivering RNAi and DNA, we are also investigating such systems for cancer treatment and conditional-release systems for ophthalmic applications,” he notes. The future of medicine is likely to depend on targeted and controlled delivery of therapeutic molecules which will make the drug more effective with minimal or no side effects, he says.

LEDs Disrupt Sleep

In the frenetic, coffee-fuelled lives of today, too many people are not getting enough sleep. Modern light-emitting diodes (LEDs) used in energy-efficient lighting as well as television and computer screens, laptops, tablets and various handheld devices, are adding to the problem, according to an article appearing today (May 23) in Nature. Lack of sleep takes its toll. “The cumulative effects of sleep loss and sleep disorders have been associated with a wide range of deleterious health consequences including an increased risk of hypertension, diabetes, obesity, depression, heart attack and stroke,” noted a 2006 report from the U.S. Institute of Medicine.
The electric light has had a powerful impact on the body’s clock, known as the circadian rhythm. “And light affects our circadian rhythms more powerfully than any drug,” remarked Charles A. Czeisler in his perspective article in Nature’s Outlook feature on sleep. He is a sleep specialist with Harvard Medical School and Brigham and Women’s Hospital at Boston in the U.S. Apart from rods and cones needed for vision, the eye’s retina also contains ‘intrinsically photosensitive retinal ganglion cells’ (ipRGCs). These light-sensitive cells help synchronise the body’s circadian rhythm to the natural day and night cycle.
When artificial light strikes those cells, the body gets misled and responds by promoting wakefulness and inhibiting sleep. Consequently, “many people are still checking e-mail, doing homework or watching TV at midnight, with hardly a clue that it is the middle of the solar night,” observed Dr. Czeisler.
“Technology has effectively decoupled us from the natural 24-hour day to which our bodies evolved, driving us to go to bed later. And we use caffeine in the morning to rise as early as we ever did, putting the squeeze on sleep.” White light emitted by LEDs was typically rich in blue light.
This mattered because ipRGCs were most sensitive to blue and blue-green light. So night-time exposure to LEDs was typically more disruptive to circadian rhythms and sleep than the old incandescent light bulbs. Since solid-state light fixtures could carry multi coloured LEDs, it would be relatively easy to control their light intensity and colour composition. “The adverse effects of night-time light on sleep and circadian rhythms can be reduced by replacing blue-enriched light with red- or orange-enriched white light after sunset,” he suggested. In addition, “it is critical to establish a regular bedtime and wake time,” said Dr. Czeisler in an email. The interval between those two times must allow a person to catch enough sleep. An average adult needed eight hours of sleep.
Children needed more sleep. A typical high school student would need more than nine hours in bed. “Children become hyperactive rather than sleepy when they don’t get enough sleep, and have difficulty focusing attention, so sleep deficiency may be mistaken for attention-deficit hyperactivity disorder (ADHD), an increasingly common condition now diagnosed in 19 per cent of U.S. boys of high-school age,” he pointed out in the article.

Focus on Plant Proteins to Feed Billions

Growing food sustainably to feed a growing global population will require improving the way staple crops take in and transport substances, says a group of a dozen scientists from six countries. As it was, some two billion people in the world were suffering dietary deficiencies that had an enormous impact on their health, noted Julian Schroeder of the University of California at San Diego in the U.S. and his colleagues in a Perspective article appearing today (May 2) in Nature .
During the next four decades, an expected additional two billion humans would require nutritious food. “Global demand for food is predicted to increase by 40 per cent by 2030. Innovative solutions are required to increase production on the land currently used for agriculture, because we are already close to the sustainable limit of 15 per cent of the Earth’s surface that can be exploited for crop production.” Utilising the biology of a class of plant proteins known as ‘membrane transporters’ could be a “key contributor to the goal of global food security,” they said. These proteins, embedded within membranes of cells, could improve the efficiency with which plants took up and used water and nutrients. The transporters were also central to mechanisms for drought tolerance in plants as well as their ability to grow in other adverse conditions, such as in saline or acidic soils.

Salt Tolerance

The ‘HKT’ family of transporters, for instance, moves sodium and potassium, and plays an essential part in salt tolerance. In the course of fundamental research using the plant Arabidopsis thaliana , Prof. Schroeder’s lab discovered the genes for these proteins and their mechanism for improving salt resistance.
Recently, agricultural scientists in Australia, led by co-author Rana Munns, used marker-assisted breeding to move members of this gene family from a wild, salt-tolerant wheat species to a commercial variety, boosting the latter’s yield by 25 per cent in field trials. “Aluminium tolerance genes are also very promising for enhancing yields in acidic soils,” said Prof. Schroeder in an email. Such soils, with low crop yields, were widely distributed in sub-tropical and tropical regions of the world where developing nations are located. Many millions of people in the world suffered from iron and zinc deficiencies “because their plant-based diets are not a sufficiently rich source of these essential elements,” the scientists observed in their paper.

Boosting Iron Content

To fortify rice with more iron, scientists had turned on key transporter genes in the plant’s seeds. These genes are usually expressed in the root so that the plant could take in nutrients from the soil. The result was a greenhouse-grown rice with three- to four-fold higher levels of iron in polished grain. In a similar fashion, zinc content of cereal grains could be increased, according to Dale Sanders, director of the John Innes Centre in the U.K. and another co-author. His team had demonstrated this with barley. “We are also in the early stages of research to increase iron and zinc content in wheat,” he added in an email.

Fertiliser Reduction

Targeting appropriate membrane transporters could increase the efficiency with which plants took up phosphorus and nitrogen. The amount of phosphate and nitrate fertilisers used for cultivation could then be substantially reduced. “This is an important goal for sustainable high-yielding agriculture,” remarked Prof. Schroeder in his email. However, more basic research was needed into the fundamental mechanisms operating in plants.

Raw Horse Gram Good for Diabetics

With dietary practices increasingly linked to lifestyle diseases, here is some news to cheer about for diabetics. Scientists from the Indian Institute of Chemical Technology have found that unprocessed raw horse gram seeds not only possess anti-hyperglycemic properties but also have qualities which reduce insulin resistance. The scientists made a comparative analysis between horse gram seeds and their sprouts and found that the seeds would have greater beneficial effects on the health of hyperglycemic individuals. Dr. Ashok Kumar Tiwari, Principal Scientist and lead author of the study said increased consumption of highly processed foods was contributing to spiked levels of blood glucose and lipid levels. He said South Asians consume more carbohydrates, and the introduction of polished white rice has contributed to increased levels of blood sugar among them. Quoting an earlier study carried out at IICT, he said it was noticed that brown rice or pounded rice was less glycemic than polished rice. He said that persistent hyperglycemia induces oxidative stress which in turn generates free radicals. These free radicals damage bio-molecules leading to imbalance in physiological functions and development of diabetic complications. Describing horse gram (Ulavalu in Telugu, Kulthi in Hindi, Kollu in Tamil) as a poor man’s pulse crop in South India, he said it was an anti-oxidant rich food grain. Traditionally different preparations were made with the pulse to suit the requirements of different seasons. For instance, it was given in the winter for generating body heat/warmth and energy.
The authors of the study, which was published recently in Nutrafoods, said: traditional medicinal texts describe its use for asthma, bronchitis, leucoderma, urinary discharge, kidney stones and heart disease. Dr.Tiwari said the study found that raw horse gram seed was rich in polyphenols, flavonoids and proteins, the major anti-oxidants present in fruits and other food materials.
Anti-oxidants help in controlling oxidative stress by scavenging free radicals. He said the study found that raw horse gram seed has the ability to reduce post-prandial hyperglycemia by slowing down carbohydrate digestion and reduce insulin resistance by inhibiting protein-tyrosine phosphatase 1 beta enzyme. He said that of late a belief has gained ground that eating sprouts of horse gram would be beneficial for health.
However, the study found that during sprouting its anti-diabetic medicinal property gets reduced. He said the majority of anti-oxidant properties were confined to the seed coat and its removal would not do any good. “Any preparation made of whole grain is better than sprouts or horse gram pulses”, he added.