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A Crustacean Band Aid For Burn Victims


Developments to Watch

A Crustacean Band-Aid for Burn Victims

There are more uses for crabs than a good shore dinner. Researchers at North Carolina State University have developed a biodegradable wound dressing for burns made from chitosan, a natural fiber extracted from crab shells. In tests on pigs, the three-layered bandage protected the wound from bacteria as the inner two layers were absorbed into the skin.

Burn dressings now in use must be regularly reapplied, which disturbs the wound and can be quite painful if scabs adhere to the dressing. But chitosan, used in the bottom layer of the new bandage, is easily absorbed by the human body, so it need never be removed. In fact, it acts as a cellulose-like scaffolding on which new cells can grow. And because chitosan is known to resist funguses, microbes, and viruses, it actually speeds healing. North Carolina State textile professor Samuel Hudson says the fiber also suppresses the undesired cell growth that causes scarring.

The second layer is made of a polymer that also degrades and becomes part of the skin. It has the consistency of cellophane and acts as a second line of defense after the chitosan breaks down. The outermost layer is a cotton gauze that, like traditional dressings, is changed occasionally. The researchers, who presented their bandage at the American Chemical Society's annual meeting in August, said further research is needed to perfect the balance of moisture in the bandage to promote healing. They should have no trouble finding supplies. Chitin, the base of chitosan, is the earth's second most abundant organic resource after cellulose.Edited by Catherine ArnstReturn to top

Building a Smarter Mouse

A team of academic scientists has created a strain of supersmart mice by adding a gene that boosts their ability to learn and memorize. Plus, the mice's brains don't slow down as they age. The research, reported in the Sept. 2 issue of Nature, proves that genetic improvement of intelligence in mammals is feasible, say the scientists. In the near term, drug companies could try to develop memory-enhancing medicines that target that same gene in humans.

The smart mice--a strain named Doogie after Doogie Howser, M.D., a TV show about a child genius--carry extra copies of the NR2B gene, which controls the brain's ability to associate one event with another. The gene programs a protein called NMDA that serves as a receptor in the brain for signals associated with memory. The receptor needs two signals--such as a lit match and a sensation of heat--to create a memory. In young mammals, the NMDA receptor makes such connections very quickly, but it slows down after adolescence, and learning and memorizing become harder.

Princeton University neurobiologist Joe Z. Tsien and colleagues from Massachusetts Institute of Technology and St. Louis' Washington University bioengineered the mice with extra copies of the NR2B gene, designed to increase in activity as the mice age. Tsien says the Doogie mice were much better than normal mice at solving maze problems, learning sounds, and retaining knowledge, and their brains retained the biological characteristics of juvenile minds.Edited by Catherine ArnstReturn to top

Road Noise: Turning Down the Volume

Highways can be horrendously noisy, and the concrete and wooden buffers that cities build to dampen the din are often inadequate. Purdue University's new Institute for Safe, Quiet, & Durable Highways thinks better solutions to noise pollution may be found where the rubber meets the road. Armed with a $3.6 million grant from the Transportation Dept. and matching funds from the auto industry and state governments, the Institute aims to reengineer both pavement and car tires.

This isn't the first such reengineering effort. More than a decade ago, tiremakers learned to reduce the high-speed whine of car tires on the highway by randomly varying the shapes and sizes of their treads. Purdue wants to go a lot further, though, and is studying some of the same tricks the U.S. Navy employs to cover the sonic tracks of its submarines--analyzing how the sound is generated, then nipping it in the bud. "Once we understand the sources of noise on roads, we'll find better strategies for making them quieter," says Institute Co-Director Robert J. Bernhard.By Neil Gross; Edited by Catherine ArnstReturn to top


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