the-BA : Science News Digest

In the news this week: scientists unveil both the thinnest and the blackest materials ever, impulsive rats shed light on drug addiction and International Polar Year is launched. Plus, snails aren’t as slow as they look...

In a move that could revolutionise medical research and computers, scientists at the University of Manchester have created the thinnest material ever. Called graphene, the substance is just one carbon atom thick – that’s 0.35 nanometres, 200,000 times thinner than a human hair. The carbon layer was created two years ago, but previously could only be made when stuck to another material. Now, however, it has been created as a film suspended by nanoscale gold scaffolding, and it has been found to be surprisingly stable – even at room temperature and in vacuums.

Its main applications are anticipated to be in drug research and in vastly increasing computer speeds, the Times reported. It could be used in electron microscope imaging – by serving as the support to place sample material on. Since image definition is currently limited by the thickness of the support material, the use of graphene could result in much clearer images.

BBC News reported that scientists have made a surprising discovery about the way skin cells divide, which may have implications for the development of dangerous skin cancers.

The outer layer of skin is shed everyday, replaced by an inner layer of new cells. It was generally believed that a conveyor-belt system of replenishment existed – where short-lived cells that soon stopped dividing were produced by stem cells at the base layer of the skin. However, when the research team from the MRC Cancer Cell Unit in Cambridge tracked the division of individual skin cells in mice for over a year, with specific genes highlighted by a fluorescent marker, they discovered that the supposedly short-lived cells were actually continuing to divide. Following division, one of the cells would stop growing, leaving only one cell to continue the process. Stem cells, on the other hand, were only springing into action if the skin was unhealthy or damaged and needed repairing.

Lead researcher, Dr Philip Jones, said, ‘One of the implications of what we've seen is that these progenitor skin cells can potentially go bad and cause skin cancer if they linger long enough.’ He hopes one day to be able to model the evolution of cancer from the single cell stage onwards, to help find better ways to tackling the disease.

New research using rats has identified a biological basis for the link between impulsive behaviour and a susceptibility to drug addiction. Scientists distinguished impulsive rats using a specially designed test where the rodents were trained to wait for a light that signalled food delivery, before moving towards it. The impulsive animals which continued to pre-empt the light, despite the fact that this meant they forfeited the food, were significantly more likely to become addicted to cocaine, and gave themselves more hits per hour.

Brain scans of the rats revealed that the impulsive ones had fewer dopamine receptors in a particular part of their brain – the nucleus accumbens.

‘There are several studies now showing [dopamine] receptors to be a natural 'brake' in the brain that regulates the amount of drug intake; too few and intake seems to increase,’ said Jeffrey Dalley, one of the researchers, in the Guardian. ‘This is the first study to link such changes with impulsivity.’

While the Times highlighted the threat that poaching poses for elephants – despite a global ban on the sale of ivory, up to five per cent of Africa’s elephant population are killed every year – the Guardian revealed how a genetic map of the continent’s elephant herds has helped trace the origins of a multi-million pound haul of contraband tusks seized in Singapore. Up to 6,500 elephants are estimated to have been killed for the ivory.

Genetic signatures for the various elephant populations in different African regions were identified after analysing DNA from their tissues and dung. DNA retrieved from the seized tusks was then compared.

Bill Clark, co-author of the published study said: ‘Now [we have this genetic map] we can trace [the ivory] back beyond export to the point of poaching, where the original crime is committed. This gives enforcement officers information on which populations are being hit and so where they need to invest their resources. It's a very timely development, because poaching has intensified dramatically in recent years.’

Research published in the journal Science has identified the 13 towers of Chankillo, in Peru, as a solar observatory, and suggests sun worshipping was happening in South America almost 2,000 years earlier than previously believed. The 13 towers run north to south over the brow of a low hill, part of a ceremonial complex dating back to the fourth century BC.

‘Chankillo provided a complete set of horizon markers – the 13 towers – and two unique and indisputable observation points,’ said Professor Clive Ruggles, one of the paper’s authors, in the Daily Telegraph. ‘The fact that, as seen from these two points, the towers just span the solar rising and setting arcs provides the clearest possible indication that they were built specifically to facilitate sunrise and sunset observations throughout the seasonal year.’

Earthwatch volunteers uncovered pottery, shell and stone artifacts at the sun rise observation point – evidence of rituals associated with sun cults.

It was a week of planetary flybys…

NASA’s New Horizons spacecraft made its closest pass of Jupiter, reported BBC News – giving it a chance to test its instruments and accelerating it towards its final destination, Pluto. It was the first close look at Jupiter and its moons since the Galileo mission in 1995. While there, it captured images of a huge volcanic eruption on Jupiter's moon Io.

Also in BBC News: The Rosetta space probe also made use of planetary gravity to change course and help it build up speed so that it can catch up with the Churyumov-Gerasimenko comet, near Jupiter. Passing within 150 miles of Mars, the European craft lost radio contact with Earth during the 15 minutes it passed behind the planet, but contact was successfully restored. The craft will now proceed on its mission to probe the chemistry of the comet, which scientists hope could help solve some of the unexplained mysteries of how the Solar System evolved.

International Polar Year was officially launched in Paris, reported BBC News. Actually due to last two years, the 763 million pound collaborative effort to study the north and south poles is one of the biggest research programmes the world has seen in fifty years, involving researchers from more than 60 countries. Climate change will be the focus of many of the 200-plus projects; including its impacts on the millions of people living in the Arctic, how badly melting ice sheets in Greenland and Antarctica might affect global sea levels, and studies of marine life under the Antarctic ice.

In related news, the Guardian reported some of the exotic animals that scientists have observed as part of the Census of Marine Antarctic Life (CMAL) project. Much of this marine life had been sealed under ice for at least 12,000 years, until global warming led to the collapse of the Larsen B ice shelf in 2002. In addition to new species, including a ten centimetre-long crustacean, the CMAL project has also discovered that other animals, such as the Minke whale, are now able to survive in the area due to rising sea temperatures.

The need to conduct such a survey was highlighted by Gauthier Chapelle, from the Brussels-based International Polar Foundation: ‘This is virgin geography. If we don't find out what this area is like now, following the collapse of the ice shelf, and what species are there, we won't have any basis to know in 20 years' time what has changed, and how global warming has altered the marine ecosystem.’

Meanwhile, in other climate change-related news, BBC News announced that some of the UK’s leading property and construction firms have joined together to form the UK Green Building Council. Approximately 50 per cent of the nation’s annual greenhouse gas emissions come from buildings: the new council aims make the building sector sustainable within the next ten years by transforming the way homes and offices are planned, designed, constructed, maintained and operated. And, while the government has already announced plans to make all new homes in England carbon neutral by 2016, the council’s chairman, Peter Rogers, thinks more attention needs to be paid to existing buildings – since they will still make up 75 per cent of buildings in 2050.

‘There are nine million wall cavities in this country that have not been filled,’ said Mr Rogers. ‘You could knock 30% of the carbon load out of building industry relatively easy. Things such as better insulation, draught exclusion, and encouraging people to switch things off, are all simple measures.’

Other news in brief:

A leading fertility researcher warned the science minister that stem cell research is being hampered by red tape.
(The Daily Telegraph)

Scientists unveiled the blackest material ever created.
(The Daily Telegraph)

And finally…

Scientists have discovered that snails do not tend to be adventurers, following the road less travelled, but instead follow the trails left by others. Mucus production is very costly in terms of energy used – burning up to two-thirds of the calories the snails consume as food, reported the Telegraph. But by using ‘snail highways’, the gastropods can save up to 70 per cent of the energy. The researchers from the University of Sunderland spent months monitoring the common periwinkle Littorina littorea and measuring trail thickness. They found that the marine snails adjusted their mucus production according to how weathered the existing trail was.