Mobile phones officially under suspicion

Mobile-phone use has joined the World Health Organization's purgatorial category of "possibly carcinogenic for humans".

A committee of experts brought together by the International Agency for Research on Cancer (IARC), a World Health Organization (WHO) scientific centre in Lyon, France, announced yesterday that it cannot rule out the possibility that heavy mobile-phone use may increase the risk of brain cancer.

The IARC's formal opinions on such matters — always based on published data — are influential, and likely to raise the temperature of an already overheated debate on mobile-phone use and health. The WHO's 'possible carcinogen' category covers 266 other radiation sources and chemicals, including certain pesticides and gasoline — and also items such as coffee, which joined the list in 1991 as a possible cause of bladder cancer. The IARC regularly puts together expert groups to evaluate evidence for the carcinogenic potential of chemicals and radiation sources that have raised concern. Its categories include 'carcinogenic', 'probably carcinogenic', 'possibly carcinogenic' and 'not classifiable'.

The IARC expert group of 31 scientists from 14 countries was headed by epidemiologist Jonathan Samet of the University of Southern California in Los Angeles. The group held a closed conference between 24 and 31 May to assess potential carcinogenic hazards associated with exposure to radiofrequency electromagnetic fields, including radio and television transmitters, as well as mobile phones.

Alison Abbott in Nature. Here

Team building: A study on the behaviour of Ants

A team of engineers has discovered how colonies of ants survive floods by forming themselves into life rafts. The work shows how many simple components can interact to create complex structures and behaviours, a subject that touches on crowd control, urbanization and robotics.

An individual ant can float on water for a few minutes, but a clump of the insects is heavy enough to break the surface tension of the water and sink. Yet when a nest of fire ants (Solenopsis invicta) is flooded, the entire thousands-strong colony shapes itself into a raft that can stay afloat for months.

"Together they form this really complex material that water should be able to get through, but can't," says Nathan Mlot, a mechanical engineer at Georgia Institute of Technology in Atlanta. Mlot and his colleagues have shown how these rafts are built and why they float. Their findings are published this week in Proceedings of the National Academy of Sciences¹.

When Mlot put thousands of ants in an empty beaker and swirled it, the insects clung to each other, gripping tightly to form a sphere that felt like a squashy ball, he says. Wearing gloves to avoid being bitten, Mlot could toss the clump in the air and catch it without any ants falling off.

When such a sphere is placed in water, it relaxes into a dome and, within minutes, flattens into a pancake.
The ants that hit the water first hook together with their jaws and legs, forming a tightly woven base. As the dome flattens and more ants reach the edge of the mass, their comrades at the bottom grip them tightly, weaving them into the base to help support the rest of the colony. At its flattest, the raft consists of two to three levels of ants, with the upper levels milling around on their interwoven nest mates.

A lone ant's exoskeleton can trap air bubbles and become slightly water repellent, but the surface of an interwoven group does so much more effectively, keeping the ants dryer.

Although the raft is porous and its base is below the water level, none of the ants are submerged, or even get wet. Instead, the ants at the base of the raft push against the water's surface and shape it around them into a bowl without breaking the surface tension.

Lizzie Buchen in Nature. More Here

The code within the code

One of the most beautiful aspects of the genetic code is its simplicity: three letters of DNA combine in 64 different ways, easily spelled out in a handy table, to encode the 20 standard amino acids that combine to form a protein.

But between DNA and proteins comes RNA, and an expanding realm of complexity. RNA is a shape-shifter, sometimes carrying genetic messages and sometimes regulating them, adopting a multitude of structures that can affect its function. In a paper published in this issue (see page 53), a team of researchers led by Benjamin Blencowe and Brendan Frey of the University of Toronto in Ontario, Canada, reports the first attempt to define a second genetic code: one that predicts how segments of messenger RNA transcribed from a given gene can be mixed and matched to yield multiple products in different tissues, a process called alternative splicing. This time there is no simple table — in its place are algorithms that combine more than 200 different features of DNA with predictions of RNA structure.

The work highlights the rapid progress that computational methods have made in modelling the RNA landscape. In addition to understanding alternative splicing, informatics is helping researchers to predict RNA structures, and to identify the targets of small regulatory snippets of RNA that do not encode protein. "It's an exciting time," says Christopher Burge, a computational biologist at the Massachusetts Institute of Technology in Cambridge. "There's going to be a lot of progress in the next few years."

The floodgates were opened by high-throughput technologies that allow researchers to compile comprehensive catalogues of RNA molecules found in various tissues and under different environmental conditions. Such techniques revealed that 95% of the human genome is alternatively spliced, and that changes in this process accompany many diseases. But no one knew how to predict which form of a particular gene would be expressed in a given tissue. "The splicing code is a problem that we've been bashing our heads against for years," says Burge. "Now we finally have the technologies we need."

From Heidi Ledford's article in Nature

To read the full article click here

Quran says:

There ar many Signs on earth for those of sure faith, and also in your own selves. Do you not see? Quran (51 : 20, 21)

Ice found on the surface of an asteroid

An asteroid circling the sun between the orbits of Mars and Jupiter has for the first time been shown to harbor water ice and organic compounds. Those traits had been associated with comets, which spring from colder, more distant reservoirs in the outer solar system, but not their asteroidal cousins. The finding supports the notion that asteroids could have provided early Earth with water for its oceans as well as some of the prebiotic compounds that allowed life to develop.

Two teams of researchers report complementary observations of the 200-kilometer-wide asteroid, known as 24 Themis, in the April 29 issue of Nature. (Scientific American is part of Nature Publishing Group.) Both analyses are based on spectroscopic observations from the NASA Infrared Telescope Facility atop Mauna Kea in Hawaii, which show absorption features that indicate the presence of water and unidentified organic compounds. The ice appears to coat the entire asteroid as a thin layer of frost. The evidence for water on 24 Themis had been presented at conferences by the two groups in 2008 and 2009 but is only now appearing in a peer-reviewed journal.


From John Matson's interesting report in Scientific American
To read the full report click here.


Quran says :
Soon shall we show them Our signs on the horizons and in their own beings until it becomes clear to them that it is the Truth. Is it not enough that your Lord is witness over everything? (The Holy Quran 41 : 53)