Biodegradable electronics

The build-up of electronic wastes, quite often toxic to humans and other life forms, has prompted scientists to search for biodegradable electronics. Recently scientists have reported a biodegradable and biocompatible battery, made from melanin, the pigment in our skins.

Melanins are found in many organisms - including plants. They are polymers composed of different types of aromatic compounds. And they make good anodes for aqueous Sodium ion batteries. Such batteries will perhaps be useful for chronic implants such as pacemakers, neurostimulators, and cochlear implants.

For more details see the current issue of the Proceedings of National Academy of Sciences. 

PNAS vol. 110 no. 52, 20912–20917 (2013)

I am back

Our science radio broadcast on Vidyavani has taken off. Science news is only one of the components of the magazine. Since the magazine is now broadcast in two slots of 15 minutes each, the demand for science news had slowed down. I was grateful for the change since it meant that I could focus on editing the documentation of the INSPIRE programme of the DST. And the fourth December workshop on Science Video Production in IISER Pune.
Now, all the pieces that I had written earlier have gone on air - with some modifications, of course - reading science on a blog like this is so different from listening to science on radio.
Anyway - I am back with more of the latest from Science. And it looks like I should be more regular in the postings.Read on.

A Step Towards Less Harmful Insecticides

A new generation of mosquito repellents would soon be in the market, if a recent paper in Nature is any indication. Anandshankar Ray and others report that they have identified the specific receptor in the antenna of the fruit fly that responds to a common insect repellent. Then, using computational methods, they screened more than 400,000 molecules that could potentially activate the receptor. And identified more than 100 that could.

Then they selected the ones that have minimum unwanted effects on human beings and tested for their ability to repel mosquitoes. Four of them were found most successful while not affecting humans at all. In fact, they had a mild aroma of grapes. Moreover, they did not dissolve plastics and are therefore more amenable to packaging compared to the existing mosquito repellents  and less costly to produce. Scientists speculate that the repellents may have applications in controlling vector borne diseases and agricultural pests.

Nature(2013) doi:10.1038/nature12594, Published online 02 October 2013

Why is Swine Flu virus called H1N1?

The swine flu virus swept through Pune this July and here is a feature that looks at the phenomenon retrospectively and reflects on the prospects of such epidemics in future.

It is called H1N1 - H stands for haemagglutinin and N stands for neuraminidase - two proteins found on the virus. Haem-agglutinin helps the virus to attach itself and gain entry into to our cells. The virus replicates itself in large numbers there. Neuraminidase helps these newly formed viruses to come out of our cells.

There are many variations of these proteins in influenza viruses. In fact scientists have identified 16 types of hemagglutinins and 9 types of neuraminidases. 144 different combinations are possible...

Naming the virus by number of the subtype of the two proteins became a convention that allows unique name to all these types of influenza viruses. Bird flu that swept the world a few years earlier is another, called H5N1.

Influenza viruses infect many birds and mammals. Quite often, humans in contact with such birds or animals also get infected. But it is rare that the virus then moves from human to human. In such occasional cases, we see a sudden epidemic of Influenza in human societies. The swine flu which swept through Pune in July was just such a case. 

Quick identification of the type of influenza virus is useful to create a vaccine in response to an epidemic. But the vaccine would not be useful later because these viruses undergo rapid changes through both genetic drift as well as genetic shifts -

abrupt changes in their genome.

In most cases, the flu is self limiting Our immune system comes to the rescue and we would be alright in a few days. Symptomatic treatment of the fever and malaise is also often used, to reduce the suffering. In some rare cases, anti retroviral drugs and neuraminidase inhibitors are also used. 

Origin of Jaws

Can you imagine if we did not have jaws? We would never be able to talk - yak yak yak..

And now scientists have discovered the beginnings of the evolution of our jaws. In China, they have discovered the fossils of a fish, the first vertebrate with jaws, that lived more than 400 million years ago.

Nature (2013) doi:10.1038/nature12690. Published online 25 September 2013

RNA Switches for Bacterial Virulence

A bacteria known as meningococcus, causes septicaemia and meningitis in children. This bacteria is quite prevalent in the nose and pharynx of humans. Yet we are normally protected by our immune system. But then, how does it suddenly infect humans? What does it do to fool our immune system?

Scientists have started unfolding the mystery with the finding that there are three RNAs in meningococcus that respond to the increasing temperature.

The hairpin bends in these three RNAs melt and separate out and that starts the transcription of three proteins. These proteins help the meningococcus to make a new kind of cell wall and to escape detection by our immune system.

Interestingly, for meningococcus, these RNA switches are a response to the threat of increasing temperature. The increase due to fever in the human body.

Such transitions from innocuous to virulent pathogens are known to happen in many other micro-organisms. The results published in Nature online in September may be a clue for many other researchers to start looking at RNA switches in other pathogens too.

Nature (2013) doi:10.1038/nature12563, Published online 25 September 2013

Carbon Computers

All life forms on the earth are Carbon based. And speculations have been abundant about the possibility of silicon based life.

Meanwhile, all computers are based on silicon. And attempts have been made to create carbon based computers. And now scientists have made a breakthrough.

Computers based on carbon nanotubes are indeed possible, says researchers from Stanford university. Read the paper in the September issue of Nature.

Nature 501, 526–530 (26 September 2013) doi:10.1038/nature12502

Jab the sperm met the egg

Ok, all of us know that we were formed by the combination of an egg and a sperm. But did you know that when the egg and sperm joined to become a zygote, initially all the work was done by the genes from the egg?

It is only after the first few divisions that both the gene sets from father and mother kick into synergised action.

And then on, it is a zygotic genome.

Till then, the cells are pleuripotent meaning each cell can become any organ. But from this time the cells start differentiating. to a large extent become unique and start responding to the neighboring cells and the surrounding environment...

There is a very interesting paper on this phenomenon in the recent Science journal, if you are interested... 

Combined with the fact that your energy production mechanism, the mitochondria, come from the mother, the continous early divisions of the fertilised egg reminds one of the efforts of the mother in creating you.

Science 341, 1005 (2013); DOI: 10.1126/science.1242527

Whistling Radio

You guys should be glad that you are listening to FM radio. Tune in to short wave, if you don't believe.

There is a huge amount of whistles and screeches and unbearable noise.

And no wonder. Our sun is very active now, sending out particles, mostly charged...

They come and hit against the magnetic field causing magnetic storms on  the earth's field and change directions themselves. Some of them come in through the poles and get trapped in the magnetic field. And soon the ionosphere swells up in response. Moving a few miles closer to the earth's surface.

Since short wave radio depends on reflection of the radio waves from the ionosphere, and the ionosphere is changing, reception becomes problematic.

Besides, the trapped electrons are sometimes accelerated by the changing magnetic field lines of earth, leading to emission of radio waves. And that is what we hear as screeching and whistling noises in short wave bandwidths.

By the way, the sun is at its peak activity and is expected to change its north south magnetic orientation. Flipping of the field takes place every 22 years or so. Wait for more in the coming posts.

And for an interesting report on the acceleration of particles in the van Allen belts, high up in the earth's atmosphere, take a look at the recent paper in Science Magazine.

Science 341, 991- 994 (2013); DOI: 10.1126/science.1237743

Conductors: Soft, Stretchable and Transparent

Electronic devises are usually hard materials. Suppose you want a devise which is stretchable, you could use metallic springs.

If you want them small as well, you could use nanomaterials - like silver or gold nanowires. Or carbon tubes, graphene, ..

These materials conduct electricity, electronically. Meaning - electrons move in the material to conduct electricity. But if you want it soft and stretchable and transparent?

Say, for instance, to implant them in human body?

You might think that the choices would narrow down. But instead, it just expands...!

Many hydrogels can conduct electricity. Are stretchable and transparent and even biocompatible.

Unlike the hard materials hydrogels are ionic conductors. Can withstand very high voltages and very high frequencies. Which expand the applicability to many technological problems.

Researchers can now have a field day generating applications with these materials.

There is a trail blazing paper in the recent issue of science.

Take a look.

Science 341, 984-987 (2013);

Science Media Centre, IISER Pune

The Science Media Centre in IISER Pune was set up with partial support from NCSTC, Department of Science and Technology in 2012. 
Initially, the primary activity consisted of training in science video production for students, teachers, researchers,.. and training media people to deal with science. And of course coverage of scientific events and some video productions. You will find some of them in Youtube.
The Science Media Centre is now moving into Science Radio a magazine format production, in partnership with Vidyavani, the community radio at Pune University. 
One of the segments in the magazine would be science news - latest discoveries in science.
The stories below arose out of this need to attract the educated public in and around Pune University to scientific research happening around the world.
The intention is to target CR in Pune University, yet science does not limit itself to Pune. Others who may want to use any of the stories are free to take these stories modify if necessary and use them. I would appreciate any comments that will help improve the usability of these stories.
I will now take a break. See you in the next episode, next week.

Climatic Classification of Indian Districts

The rainy season is coming to an end in India And the recent issue of Current Science has come out

with a new classification of districts on the basis of the climatic data between 1975 to 2005.

The earlier classification used data prior to 1970 and does not consider the possible changes in climate.

Moreover, the data sets relating to rainfall and evapo-respiration have also been becoming more precise in the recent years.

The paper claims that this new classification is more useful in agricultural planning at district levels.

Current Science, 105 (4 ):  492 - 495 491, 25 August 2013 

Deaths in Pune

Pune has a large enough number of deaths from cancer.

And many of them have diabetes.

Is there a relationship between cancers and diabetes?

In a paper published in Current Science, scientists note that there is indeed an increased percentage of certain kinds of cancers in diabetic patients as opposed to the non-diabetic. Especially of the liver, lung, pancreas and prostrate.

The data is taken from Death certificates dating from January 2006 to December 2006. In 14,838 Death certificates, 8% had diabetes and about 7% had cancer. In fact, thirty-two different cancers were seen in the diseased population.

Current Science, 105 (4 ): 486-491, 25 August 2013 

Drumming up support

Social insects like ants and bees are known to communicate with each other with chemical, tactile and visual signaling. Now here is a case of termites hitting their head against the wooden walls of their colony to drum up support in response to invasion by other creatures.

A paper recently published in Nature shows that these African termites can indeed respond to low frequency vibrations that emanate from the head hitting. But these vibrations do not travel more than 40 centimeters or so. So the others who detect these vibrations may pass on the message by repeating the drumming with their own heads, say the scientists.

Reminds one of the talking drums that are depicted in Phantom comics, doesn't it?

Do Plants feel pain?

Do plants have feelings?

Well, we would never know what they feel.

But we can definitely investigate how they respond to wounds.

If you damage the leaf, for instance, a signal, typically a jasmonate, tell the other leaves about it.

This can be detected even as electrical signals from the leaves that respond.

And what is more interesting is that the receptors for these signals

are very much like the receptors of glutamate neurotransmitter in our own brains.

A study of this phenomenon is reported in a recent paper in the journal Nature.

Nature 500, 422–426 (22 August 2013) doi:10.1038/nature12478

Spare parts for your body

Stem cell therapy has been used for many degenerative diseases in recent years. But often, after the treatment, the patient comes back to the hospital with a teratoma, a tumour with different types of tissues.

A paper in PNAS published online on August 5th, gives a possible solution to the roadblock in the use of stem cell therapies.

Scientists now know that teratoma, in such cases is often caused by some pluripotent cells or cells that can form any type of tissue.

The mitochondria of these undifferentiated cells often contain certain small molecules, whereas the differentiated stem cells that make up the organ, do not contain them.

So they can be targeted and removed by inducing programmed cell death. This result makes stem cell therapy more long lasting and without undesirable outcome of tumor growth.

Stem cell therapy could potentially challenge the organ transplantation process by growing liver, retina and even heart valves. A perhaps will be the basis for a niche industry for highly individualised spare parts for your body.

PNAS  Published online August 5, 2013, E3281–E3290

Complex Chemistry

Chemists usually consider two or three chemicals at a time in a reaction. But when there are a large number of reagents and products, and they interact by catalysis and inhibition, producing feed forward and feedback cycles, the story becomes too complex for most chemists.

Without knowing the kinetics of the individual component reactions, can we write a master equation of such complex chemical systems?

Two chemical engineers have proposed such a master equation in a recent issue of PNAS.

Besides chemists, biologists too would be very happy to have such a tool

that can describe the complex biochemical networks in living cells.

PNAS vol. 110, no. 35, 14261–14265 August 27, 2013

Treating Typhoid

Typhoid is a disease that needs long term treatment. Even though the symptoms subside soon after initiating treatment, the bacteria that causes the disease, can survive in the gut for many weeks. And prolonged antibiotic treatment without having any symptoms may lead to the patients not taking the medicines, as required. Often leading to antibiotic resistant varieties of bacteria.

Now, scientists have found that the bacteria that causes typhoid is helped by another bacteria called E.coli.

E coli, a generally useful bacteria of the gut, produces indol, a chemical signal which is used for messaging between the cells of their species. Typhoid bacteria do not produce indol.

But it has a mechanism by which it uses this chemical to develop tolerance for the antibiotic.

Scientists have been studying this type of interdependence of different bacterial species for some time now.

 But this result has immediate implication in the treatment of typhoid.

PNAS   110 (35): 14420–14425 (2013)

After smells

Television presents 25 images in one second. Yet we see it as continuous because there is an after image in our brain that lasts one-eleventh of a second. Is there a similar after image in the sense of smell?

Yes. Though the experiments showed that rat brains respond to smells in a few milliseconds.,

Even after removal of the smell, there is an after image that lasts for more than 10 breath cycles. They have also identified the particular brain area that is responsible for this phenomenon.

PNAS  Published online August 5, 2013, E3340–E3349 

From the world outside to the world inside

Bacteria are known to cause many diseases. But recent research on the bacteria of the gut shows that some bacteria are important for health.

In fact, one could diagnose insulin resistance, obesity, faulty lipid metabolism, inflammations and many other metabolic disorders by the diversity of microbiota of your intestines. 

So soon doctors may start prescribing bacteria for your illnesses. And besides probiotic dahi, the supermarket near you will be selling bacterial products to make you healthy. You can find a good review on the topic published in the recent edition of Nature journal.

But wait before you run to the supermarket to buy these good bacteria. The diversity of microflora in your gut may be reduced because of hormones and other factors. For example, increased testosterone in males after puberty gives them a different set of microbiota compared to females. Bacterial species vary depending on the food that you eat and perhaps even your psychosocial and cultural life may affect it through epigenetic means. So perhaps the disorder is causing selective removal of some species of bacteria from the gut rather than the disorder being caused by lack of certain bacterial species. It is only further research that can provide results that can be translated to treatments.

Nature 500, 541–546 (29 August 2013) doi:10.1038/nature12506

Motivation gene

Some people are highly motivated and some others are not? Why?

Why is that some people study more and work more and some others slack off? Is it something in our brain?

Latest issue of the journal, Molecular Psychiatry, reports that perhaps the Dopamine 2 Receptors in the part of the brain called ventral striatum may be responsible for the differences.

Dopamine is a well known neurotransmitter known to be responsible for response to rewarding stimuli.

There are different kinds of receptors for Dopamine and one of them, Dopamine 2 Receptor is found in different parts of the brain.

Scientists used a virus as a vector to put more copies of the gene for Dopamine 2 receptor to increase the expression of the receptor in different areas of rat brain.

When Dopamine 2 receptor was increased in ventral striatum, the rats showed increased motivation - measured by Instrumental learning, willingness to work towards goals and modulation of behaviour by rewards. 

Scientists believe that this understanding may one day, be used to treat mental illnesses that come in the way of using effort to achieve goals - including certain types of obesity and addiction.

P Trifilieff  et al. Molecular Psychiatry (2013) 18, 1025–1033