Developments to Watch
Can Bees Take the Sting out of Land Mines?
Between 80 million and 120 million land mines are buried around the world, especially in Angola, Cambodia, and now Kosovo. As the problem worsens, the need for detection systems becomes more urgent. Now, a team of scientists from the University of Montana and Sandia National Laboratories in Albuquerque is training honey bees to do the job.
The work hinges on the ability of the bees to pick up pollen and other airborne chemicals on their bodies. Minute amounts of TNT, the explosive used in land mines, often linger in the air around the weapons. TNT may also be absorbed from the soil into the pollen of flowering plants. Either way, traces of the chemical could be picked up by the bees as they forage for food. Monitoring TNT levels in the beehives, say researchers, might be a way to detect nearby land mines.
To test their idea, the researchers intend to tag 50 bees with tiny devices that track the insects' movements. A reader in the hive will scan each bee's tag every time it enters or leaves the hive. Other instruments will directly measure the air in the hive for explosives. Taken together, the data might be able to supply researchers with a road map to nearby land mines.EDITED BY ELLEN LICKINGReturn to top
Buckle Up: A Fusion Engine Is in the Works
Long, long ago, when Star Wars was still a trilogy, scientists at NASA began thinking seriously about fusion engines of the sort that might have powered Han Solo's Millennium Falcon. Chemical fuels are fine for a six-month hop to Mars. But to journey to the outer planets and back--a five-year proposition, in the case of Pluto--engineers are hoping to harness the tremendous energy released when two or more atoms fuse.
Fantasy is now hurtling toward reality. At NASA's Marshall Space Flight Center in Huntsville, Ala., fusion project leader William J. Emrich Jr. has built a prototype of a magnetic fusion propulsion system that's about one-tenth the size of an actual rocket engine. Before attempting any fusion reactions, Emrich and his colleagues must figure out how to contain superhot gas called plasma that's used to trigger such events. Their prototype is designed to test the hypothesis that plasma could be held stable by magnetic fields at 100 million degrees centigrade--the temperature required for a full-scale fusion reaction. If that indeed is so, the payoff in space travel could be huge. In terrestrial terms, Emrich says, "if you could put a fusion engine in a car, the efficiency would be equivalent to 7,000 miles per gallon."EDITED BY ELLEN LICKINGReturn to top
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Cell-Size Test Tubes for Biochemistry
To better understand biological chemistry and perhaps develop useful, new cellular structures for drug delivery, two research teams have devised artificial methods to make cell-size containers. The first group, led by chemistry professor Richard N. Zare of Stanford University, has created cellular "test tubes" for microchemistry experiments. That's important because living things don't do chemistry in big, heated vats. Reactions inside cells are triggered by proximity. In such confined spaces, it's inevitable that two reactive molecules will soon bump into each other.
Stanford's miniature vessels are made by floating a thin membrane on a liquid, then evaporating the liquid rapidly by reducing the air pressure. As the liquid "boils," molecules get trapped inside pockets smaller than the stump of a hair. When these so-called vesicles are submerged in another chemical and jolted with a mild electrical shock, pores open and admit a few molecules for a specific test.
Meanwhile, a team of scientists from the University of Pennsylvania and the University of Minnesota is developing cell-size capsules for delivering drugs or engineered genes to specific sites in the body. The team dips wires into a liquid polymer, allows it to dry, then zaps the wires with electricity. The polymer lifts off the wires and forms microcapsules, dubbed polymersomes. Daniel A. Hammer, a Pennsylvania chemical engineer, believes the polymersomes might also be put to use as artificial blood cells, since they could contain the oxygen-carrying molecules found in the body.EDITED BY ELLEN LICKINGReturn to top