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Old Dominion University researcher Mounir Laroussi figures prominently in an article about plasma-the fourth state of matter-in the February 2006 issue of National Geographic magazine.

The article notes Laroussi's invention of a pencil that shoots out a stream of cold plasma. The so called "light saber" can be used to sterilize equipment that might be damaged by heat, or to disinfect wounds and kill germs that cause plaque to develop on teeth.

The jet of plasma can blow out the cell walls of bacteria without damaging other cells.

Laroussi, associate professor in ODU's Department of Electrical and Computer Engineering and a researcher at the Frank Reidy Research Center for Bioelectrics, was assisted in the development of the plasma jet by Xin Pei Lu, a postdoctoral researcher at the Reidy Center. The center is operated by ODU and the Eastern Virginia Medical School.

The invention was publicized last year in Applied Physics Letters and on PhysicsWeb and News @ Nature.com.

Two other ODU professors have collaborated with Laroussi in research concerning health care applications of the light saber. They are Wayne Hymes, associate professor of biological sciences, and Fred Dobbs, associate professor of ocean, earth and atmospheric sciences.
Plasmas, sometime called the fourth state of matter along with solids, liquids and gases, are generated anywhere atoms are stripped of electrons, creating soups of neutral particles, charged ions and electrons. Plasmas can be found in solar flares and around lightning bolts, and, in fact, make up 99 percent of the known universe because of their common presence in interstellar space. In the denser Earth atmosphere, most plasmas are super hot and hard to control.

During the last decade numerous researchers have produced low-temperature plasmas, but Laroussi, since the mid-1990s, has been at the forefront of the research. His focus has been on ease of use and low-cost generation of plasmas. Business Week magazine named him an "expert" in cold plasmas, and gave the same designation to Karl H. Schoenbach, ODU's eminent scholar of electrical and computer engineering, who is director of the Reidy Center and holds the Batten Endowed Chair of Bioelectric Engineering.

Cold plasmas are generated when an electrical source is tailored to kick lighter electrons into high speeds without doing the same for heavier ions. This can be done with electricity that is turned on and off-or pulsed-thousands of times a second. The relative inactivity of the ions eliminates the high heat that plasmas can develop in the Earth's atmosphere and gives researchers the more manageable cold plasmas.

This article was posted on: January 25, 2006

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