FIRST DNA ROBOT
PARIS
US chemists have designed the world's first two-footed molecular robot and taken it for a stroll in a lab dish. The robot's legs, which measure just 10 billionths of a meter, are the first nanoscale device capable of bipedal movement, according to the New
Scientist.
The robot is able to "walk" because it is made out of scraps of DNA, the molecule of life, which comprises a dual strand joined together by mating pairs of chemical rungs, called bases. A single strand of DNA, like one side of a zip fastener, provides the track along which the robot moves.
The robot itself looks rather like a geometry compass, with two legs comprising 36 DNA bases. It gets attached to the walkway thanks to tiny anchor strands of DNA that are introduced into the solution and which bind to the track as well as the undersides of the feet.
To get the robot to move forward, another piece of DNA, called an unset strand, is introduced. It peels the anchor strand away from the track. This causes the foot to move forward and look for the next mating anchor strand along the line.
Repeating the procedure with the backward foot gets the robot to shuffle along.
The biped's inventors are Nadrian Seeman and William Sherman of New York University, whose work was published by Nano Letters.
"Persuading the walker to ferry a load, such as a metal atom, is the team's next challenge," New Scientist reported.
Molecular gadgets are an eagerly explored frontier. Scientists hope these innovations-most of them still at a highly experimental stage-will provide miniaturized but high-powered and extremely accurate tools for computing, medicine, and manufacturing.
AFP
SLEEP & REMEMBRANCE
PARIS
Want to learn a foreign language? Get a good night's sleep.
Research published in Nature has highlighted the power of sleep to strengthen and restore memory when it comes to intellectual tasks.
University of Chicago psychologists asked 24 student volunteers to recognize simple, phonetically similar words from a poor-quality speech synthesizer. They never heard the same word twice.
The guinea pigs began with a morning session, and by the end were able to improve their recognition rate by 21 percent compared with the start. They were building on their memories of sounds to "generalize," or give themselves a guide as to the meaning of each new sound. Those who were tested a second time 12 hours later-but who had not had a sleep-saw their accuracy improvement slump to just 10 percent. But those who had had a sleep in between the two tests were just as accurate as before.
And, crucially, the first group, which suffered a fall in accuracy, could recover their performance so long as they had a sleep. "Sleep can rescue memories that have spontaneously deteriorated and ... memories involving generalization can be recovered," says Karim Nader, a psychologist at Montreal's McGill University, in a commentary.
AFP
YOUNGEST DIABETIC
HAMBURG, Germany
An obese five-year-old child living in east Germany has become the youngest child ever to suffer from type 2 diabetes, according to an expert cited in the German magazine Der Spiegel. The child, whose name and gender have not been disclosed, weighs 40 kilograms, around twice the average weight of a child of that age.
"Up till now, a French child of nine was the youngest diabetes case we have registered," Wieland Kiess, president of the German Diabetes Society, said.
AFP
11 million Children under five who died in 2000.
150 million malnourished children in the developing world.
1.1 billion Primary-school-age children who were not in school in 1999.
2.4 billion People worldwide who have no access to safe drinking water. People worldwide who still live without access to sanitation.
18 million Babies born each year who weigh less than 2.5 kilos.
34 million Children not immunized with DPT3.
41 million Newborns not protected from learning disabilities attributed to iodine deficiency.
50 million Annual births worldwide that are not registered.
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