In brief– Research news and discovery

A POPULAR video game could

provide doctors with a way of

diagnosing depression.

With some illnesses, such

as diabetes, a simple test can

usually quantify how severe a

person’s condition is, but

depression is more complicated.

The condition has been linked

to a shrunken hippocampus, a

part of the brain that also plays

a role in spatial memory, so

The participants, who were

already familiar with the town,

were asked to find their way to

as many landmarks as possible

within a set amount of time.

Depressed people found their

way to an average of 2.4 locations

compared with 3.8 locations

for healthy controls. Indeed,

the more depressed a person was,

the lower the score (The American Journal of Psychiatry, vol 164,

p 516). Gould hopes the test may

eventually provide a quantifiable

measure of depression.

Neda Gould at the US National

Institute of Mental Health in

Bethesda, Maryland, and her

colleagues wondered whether a

video game that tests spatial

memory could help measure

the severity of the illness.

To test their idea the

researchers developed a game

based on some scenes from Duke

Nukem, a game in which players

navigate around a virtual town.

Video game helps detect depression

ASTEROIDS get a real kick from

sunbathing. The irregular shape

of these space rocks means that

as infrared light from the sun

bounces off them, they spin

faster – perhaps eventually

leading to the break-up of large

asteroids into smaller bodies.

This effect, called YORP,

is making the asteroid known

as 1862 Apollo spin so much

faster that it now completes

one more revolution during its

orbit of the sun than it did

40 years ago, astronomer Mikko

Kaasalainen and colleagues

report in Nature (DOI: 10.1038/

nature05614). The YORP effect

was first predicted in 2000,

but this is the first observational

evidence to back it up.

Another team has reported

that the rotation of a second

asteroid, NEO 54509, has also

speeded up (Science, DOI: 10.1126/

science.1139040), lending yet

more credibility to YORP as a

driver of asteroid evolution.

Speed bumps

WHAT’S the new black? Try the

world’s least reflective material.

Change a substance’s refractive

index and you can cut the amount

of light it reflects. Now physicists

have made a coating with the

lowest index ever reported.

Fred Schubert of Rensselaer

Polytechnic Institute in Troy, New

York, and colleagues made films

of silicon and titanium dioxide

nanorods, which they then

deposited onto a surface at an

angle of 45 degrees. The coating

is full of empty spaces, giving it

a refractive index just 5 per cent

more than that of air. Adding

further layers cuts reflections still

more (Nature Photonics, vol 1,

p 176). Such coatings could make

better silicon-based solar cells,

which reflect at least 30 per cent

of the light that falls on them.

Dark materials get darker

ATHLETES who inject themselves with synthetic insulin

to boost their performance could soon be caught out by

a simple urine test. Athletes and bodybuilders sometimes

inject insulin because it makes carbohydrates from food

burn more efficiently, providing extra energy.

It also prevents muscle breakdown.

Sports authorities banned insulin in 1998 amid

rumours that bodybuilders were abusing it, but until

now there has been no test available to detect cheats.

In the interim, new forms of insulin with longer-lasting

effects have been developed.

These synthetic forms of insulin only differ from the

natural version by a couple of amino acids. Wilhelm

Schänzer and his colleagues at the German Sport University

in Cologne have now managed to identify the unique

“fingerprint” of long-lasting insulin using a technique

called mass spectrometry. This breaks the insulin into

fragments and separates them according to weight,

generating a spectral pattern of peaks which would look

different for synthetic and natural insulin (Analytical Chemistry, DOI: 10.1021/ac062037t).

The test is being evaluated by the World Anti-Doping

Agency and should be ready for the 2008 Olympics in

Beijing, China.

DAVI

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Cheating athletes will soon be rumbled by insulin test

18 | NewScientist | 10 March 2007 www.newscientist.com

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