Stories of Modern Science ... from UPI

STARS AND MAGNETIC FIELDS

How would our Sun behave differently if it had a closely orbiting twin? While astronomers don't know the exact answer, NASA's Chandra X-ray Observatory has observed an intriguing star system that is beginning to provide important clues. Scientists from the Smithsonian Astrophysical Observatory are using Chandra to study two stars in an incredibly tight binary system. These stars, part of the system known as 44i Bootis, orbit so quickly that that they pass one another every three hours. "The Universe has gift-wrapped a wonderful laboratory for us to study stars like our Sun," says Nancy Brickhouse. "We can use this strange alignment of these two stars whipping around each other to learn more about magnetic fields and outer atmospheres in stars like our Sun." For decades, scientists have known that the Sun, at the center of our Solar System, creates complex magnetic fields as it spins on axis roughly once every month. The team took advantage of the fact that 44i Bootis is an eclipsing binary, where two stars circle around each other. The two stars are aligned so that Chandra can capture the ebb and flow of radiation as the stars pass in front of one another. Using the Doppler effect -- the same process that causes a siren to change its frequency as an ambulance approaches -- scientists were able to measure a tiny wavelength shift in the X-rays emanating from hot gas filling the magnetic field structures.

ANCIENT CHINESE CURE MAY TO KEY TO CANCER TREATMENT

Two bioengineering researchers at the University of Washington have discovered a promising potential treatment for cancer among the ancient arts of Chinese folk medicine. The study, published in Life Sciences, describes how the derivative of wormwood -- artemisinin -- killed virtually all human breast cancer cells exposed to it within 16 hours. "Not only does it appear to be effective, but it's very selective," Henry Lai says. "It's highly toxic to the cancer cells, but has a marginal impact on normal breast cells." Artemisinin, isn't new, it was apparently extracted from the plant Artemesia known as wormwood, thousands of years ago by the Chinese, who used it to combat malaria. The treatment was lost, but rediscovered during an archaeological dig in the 1970s that unearthed recipes for ancient medical remedies. It became widely used to fight the mosquito-borne malaria. "Cancer cells need a lot of iron to replicate DNA when they divide," Lai says. "As a result, cancer cells have much higher iron concentrations than normal cells." The researchers pumped up the cancer cells with maximum iron concentrations and then introduced artemisinin to selectively kill the cancer. When artemisinin comes into contact with iron, a chemical reaction ensues killing the cancer cells.

A NEW WAY OF COOLING OR HEATING

According to the British science journal Nature, there's been a major breakthrough in the world of thermoelectric materials. Scientists at Research Triangle Institute in North Carolina came up with a device that could someday make both

freon-dependant refrigerators obsolete. By passing a current through thousands of super-thin layers of two different semi-conducting materials, scientists can make something hotter or colder -- depending on which way the current flows -- over 20,000 times faster than anything today. In addition to the cooling applications of such a device, these thermoelectric materials could someday be used to convert heat into electrical energy in a far more efficient manner than is possible now. Research began in 1993 as part of a program to look for alternatives to freon-based cooling systems aboard U.S. Navy ships. According to the researchers, ultimately these new materials will be engineered into many devices and eventually into plug-in modules at an affordable price. The researchers have cleared the first hurdle: demonstrating the scientific feasibility of engineering such a material into prototype devices.

WATER MAY HAVE BEEN ON MARS LONGER THAN THOUGHT

An analysis of high-resolution topographic maps and photographs, as well as recent studies of Martian meteorites suggest the presence of water on the Red Planet longer than scientists had previously believed. Researchers at Washington University in St. Louis and the University of Colorado analyzed topographic maps based on data returned from the Mars Orbiter Laser Altimeter (MOLA) on the Mars Global Surveyor (MGS) mission. They also used earlier analyses of Martian meteorites to help constrain models of the ancient climate of Mars. The meteorites contain weathering deposits produced from liquid water filling cracks and voids in the rock within the last billion years. This work led to a better understanding of when, and how much, water was on Mars in the past. "Certainly water was circulating in the upper part of the Martian crust within the last billion years," says Brian Hynek. "And even until today, water seems to be an important agent in some places on the surface of Mars that would argue for very near surface water on a lot of the planet." A recent discovery indicates the presence of small gullies at high latitudes on Mars that were formed in the very recent past and may still be active today, the researchers write in the Journal of Geophysical Research.

(For more information, about, CHINESE, call 206 543-2580; about MARS, call 314 935-5272.)