Safer and better antenna patented

The use of hand-held radios and cellular phones is up, and so is concern about radiation absorption from the antenna. A Virginia Tech researcher has patented a high performance, low radiation-hazard antenna for hand-held devices.

Electrical engineer Warren Stutzman says his antennas can perform even better than conventional antennas. With conventional antennas, the signal is transmitted in all directions. Stutzman's "Safetenna" eliminates transmission in the direction where the signal would be blocked by the user's head. This avoids potentially harmful absorption of power by the user's body and allows all of the antenna's power to be transmitted.

"The goal of improved performance for communication is in harmony with safety; there is no trade-off," says Stutzman, a faculty member in the Center for Wireless Telecommunications.

Stutzman's antenna is designed for devices operating at 1900 megahertz (MHz) and above. Use of the higher frequencies is being pioneered to supplement the crowded cellular bands that operate at 800 MHz.

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Patent awarded for quick water test

Outbreaks of intestinal diseases caused by contaminated water are on the rise worldwide. More than half of these outbreaks are caused by viruses, according to Charles Hagedorn, Virginia Tech professor of crop and soil environmental sciences.

Marian Ijzerman, a 1994 Ph.D. graduate now with the EPA, along with Hagedorn and biology professor Joe Falkinham, has received a patent for a "rapid virus detection technology," which they developed for drinking water, recreational waters, and groundwater.

The enzyme-based test is easy, inexpensive, sensitive, and very specific. The test detects the presence of a virus indicator (coliphages). "The rapid virus detection technology is based on the fact that many viruses cause susceptible cells to break open and release their cellular contents. Thus, the release of compounds normally only found within cells indicates the presence of a virus," says Hagedorn.

"An advantage of the rapid virus test is that viruses usually live longer in water samples than bacterial cells, thus presence of virus can indicate previous fecal contamination of water after living cells have died," says Falkinham. "Also, numbers of symptom-causing E. coli viruses may be better indicators of human health risk in drinking and recreational waters than numbers of bacteria."

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Unique bridge being built in Blacksburg

The first road bridge in the United States made of composite materials will be constructed over Tom's Creek in Blacksburg.

The low-cost, low-maintenance bridge to replace a corroded steel bridge in June 1997 is the joint effort of Virginia Tech, the Town of Blacksburg, Virginia Department of Transportation, Virginia Transportation Research Council (VTRC), Morrison Molded Fiberglass of Bristol, Va., and the Virginia Center for Innovative Technology.

As designed by civil engineering professor Richard Weyers, Jack Lesko of the Tech engineering science and mechanics department, and Jose Gomez of the VTRC, the new bridge will rest on the existing concrete foundations. The bridge's roadway, or deck, will be constructed of transverse glulam wood panels treated with creosote and will be overlaid with a new waterproofing system developed by Tech forest-products researchers. The preformed, self-adhering membrane of woven fibers placed between the two layers of asphalt will keep water from reaching the wooden deck.

Composite beams weighing about 200 pounds will replace the current 420-pound steel beams. Weyers says municipal crews can handle the lightweight beams themselves, saving the expense of hiring extra crews and large equipment. The major cost-saving factor, however, is the composite's resistance to corrosion. Construction should take only about a week.

"Our composite construction plan isn't a cure-all," Weyers says, "but it will be the best use of materials for low cost and low maintenance for small bridges that carry low volumes of traffic."

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Short-term therapy effective in breaking pot addiction

Research conducted during the past seven years by psychology professor Robert Stephens suggests that people who use marijuana regularly may be just as addicted as alcohol, cocaine, or heroin abusers. His research also shows that motivation, not months of psychoanalytic therapy, may be the key to breaking the addiction.

Stephens and a colleague at the University of Washington-Seattle worked with young adults who used marijuana multiple times daily. One group received counseling for four months; others went through two individual one-hour sessions; the rest received no intervention. The first two groups had equal success in quitting or drastically reducing marijuana use.

"This suggests that our most important work may be getting people motivated enough to make the change," Stephens says. That can happen in just a few well-structured hours during which patients are convinced that they have the ability to change. He adds that, for some people, months of therapy supports the belief that change is very difficult or even impossible. "It almost gives them permission not to make the effort."

Although initial success rates have been good, only about 20 percent were still abstinent after a year. "This high relapse rate, which is very similar to those of other substance abusers, shows that marijuana is truly an addiction," Stephens says.

Stephens and his colleague have received a grant to fund a study at drug-abuse treatment agencies around the country.

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