15 January 2011 | NewScientist | 17

Tree-like molecule sets size record

MEET PG5, the largest stable synthetic molecule ever made. With a diameter of 10 nanometres and a mass equal to 200 million hydrogen atoms, this tree-like “macromolecule” paves the way for sophisticated structures capable of storing drugs within their folds, or bonding to a wide variety of different substances.

Macromolecules abound in nature, and PG5 is about the same size as a tobacco mosaic virus. But making large molecules in the lab is tough, as they tend to fall apart. Previously, polystyrene was the largest stable synthetic molecule, at 40 million hydrogen masses.

To create their molecular giant, Dieter Schlüter at the Swiss Federal Institute of Technology in Zürich and colleagues started with standard polymerisation, in which smaller molecules join up to form a long chain. To this carbon and hydrogen backbone, they added branches made of benzene rings and nitrogen, as well as carbon and hydrogen, producing a tree-like structure. They then performed several similar cycles, adding sub-branches to each existing branch, to make PG5 (Angewandte Chemie, DOI: 10.1002/anie.201005164).

Coffee and aspirin combo knock hangover on the headHEAVY drinkers might cure their hangover with a cup of coffee and a painkiller – at least if the chemical acetate is the cause of that pounding headache.

Michael Oshinsky at Thomas Jefferson University in Philadelphia, Pennsylvania, and colleagues tested the effect of low doses of ethanol – about the equivalent of a single drink – on rats prone to migraines. Because low doses of alcohol typically cause headaches in migraine sufferers, this allowed them to study an alcohol-

induced headache without the complication of intoxication. Sure enough, 4 to 6 hours after imbibing, the skin around the rats’ eyes became sensitive to touch, a sign they had a headache.

None of the commonly cited causes of hangovers could have caused this response, says Oshinsky. The rats were not dehydrated and they received pure ethanol. Nor did they get a headache from acetaldehyde build-up, which has been blamed for hangover headaches: the rats were given drugs to block

NEANDERTHALS, bless ‘em, were never going to win any beauty contests. Now scans of their skulls show their robust faces, with wide noses and prominent cheekbones, weren’t even adaptations to the cold.

The Neanderthal face shape was thought to be a result of the growth of large sinuses, which warm inhaled air. To find out how big their sinuses were, Todd Rae at Roehampton University in London and colleagues analysed data from X-rays and 3D CT scans of Neanderthal skulls. When the team compared these scans with those of the skulls of Homo sapiens

from temperate regions, they found Neanderthals’ sinuses were only bigger because they had bigger faces; the two species’ sinuses had the same relative size relationship (Journal of Human Evolution, DOI: 10.1016/j.jhevol.2010.10.003). This suggests that their faces were not shaped to deal with extreme cold, the team say. In the image above, the skull on the right is a Neanderthal, that on the left is Homo sapiens.

Rae says we can now dismiss the cold adaptation idea. “This allows us to think about Neanderthals and their lives in new ways.”

Cold no impact on Neanderthals’ face

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conversion of acetaldehyde into acetate. In contrast, rats given acetate directly developed signs of a headache (PloS One, DOI: 10.1371/journal.pone.0015963).

Caffeine and anti-inflammatory drugs block some of the effects of acetate – one reason why they may give relief, says Oshinsky.

Dan Levy at Harvard University is wary of calling the rats’ headache a hangover, but says the study is an important step towards understanding alcohol-triggered headache.

Chess players use both sides of brain

IT MAY take years of hard work to become a chess grandmaster, but it gives a real boost to the brain – for working out chess problems, at least. It seems expert chess players use both sides of their brain to process chess tasks, rather than just one.

Merim Bilalic at the University of Tübingen in Germany used fMRI to scan the brains of eight international chess players and eight novices while they identified either geometrical shapes or whether the pieces on a chess board were in a check situation. The expert players were quicker at solving the chess problem, activating areas on both sides of their brains as they did so. The novices used just the left side (PLoS One, in press).

Bilalic had expected the expert players to use a faster version of the processing mechanism used by novices. “But once the usual brain structures were engaged, the experts utilised additional complementary structures in the other half, to execute processes in parallel,” he says.

This parallel processing didn’t occur when the expert players carried out the geometry task, suggesting that it is limited to practised skills. “It shows that there really is no short cut to expertise,” says Bilalic.

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