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News Tip


March 19, 2002

For more information on these science news and feature story tips, please contact the public information officer at the end of each item at (703) 292-8070. Editor: Josh Chamot

Increasing Photonic Efficiency: Nature Knows Best

Scientists have been trying for years to apply the principles underlying photosynthesis to the development of a new generation of molecular-scale photonic, or light-dependent, devices.  Now, a team of chemists supported by the National Science Foundation (NSF) has produced efficient molecular photonic switches with porphyrins, synthetic compounds related to the chlorophyll molecules produced in photosynthesis.

Using high-speed laser technology, Jonathan Lindsey of North Carolina State University (Raleigh), Dewey Holten of Washington University (St. Louis), and David Bocian of the University of California (Riverside) uncovered how light energy flows efficiently from one end of a molecular chain of interconnected porphyrins to the other end. They developed an electrochemical means to rapidly interrupt the energy flow and cause the light output to turn on and off in a few trillionths of a second.

The chemists also found that ultra-fast electronic communication takes place not just between adjacent molecules in a porphyrin chain, but between molecules far removed from one another in a phenomenon called superexchange.  They are using this knowledge to design larger and more complex arrays of porphyrins that will further increase the efficiency of photonic devices.  [Amber Jones]

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Biologists Aim to Find and Grow "Bugs" Responsible For Greenhouse Gas Methane

They've been at it for millions of years, but little is known about wetlands bacteria that turn organic matter into the greenhouse gas methane.  Now, for the first time, a team of scientists funded by NSF and affiliated with Cornell University is collecting methane-generating bacteria (called methanogens) from oxygen-poor wetlands, and bringing them to a lab alive.

According to Cornell microbiologist Stephen Zinder, no one has ever cultured and grown methanogens from acidic wetlands in a laboratory.  Scientists need to know more about the conditions where the methanogens work, he says.

Observatory sites include McLean Bog, a few miles northeast of Cornell's Ithaca campus.  The bog formed approximately 13,000 years ago when a massive chunk of glacier from the last ice age melted and left a kettle-hole in the surrounding gravel. Sphagnum moss, carnivorous pitcher plants and related species cover the surface of the bog, but researchers in the microbial observatory project are interested in extracting the methanogens living beneath the bog surface.

Zinder points out that, if the researchers succeed in duplicating the carbon-rich, anaerobic, acidic conditions where methanogens thrive, the organisms may have a future in bioengineering – perhaps in bioremediation of contaminated sites or in the controlled production of methane.  [Cheryl Dybas]

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Women, Minorities, Persons With Disabilities; Progress in Education, Less So in Workforce

Although women, minorities, and persons with disabilities have made educational progress in science and engineering fields, they continue to be underrepresented in the science and technology workforce, according to data gathered by the Division of Science Resources Statistics at the National Science Foundation.

The number of women receiving bachelor’s degrees in science and engineering equaled that of men for the first time in 1998, according to the information gathered by NSF.  In addition, Blacks, Hispanics, and American Indians/Alaskan Natives are now as likely as whites to major in science and engineering at the college level.

However, while more degrees are being awarded to underrepresented minorities than in previous years, graduation rates are lower than compared to whites.  In addition, Blacks, Hispanics, and American Indians/Alaskan Natives are underrepresented in engineering and scientific professions. Persons with disabilities represent 1 percent of the persons earning science and engineering doctorates in 1999 and more than 12 percent of the college-educated population, yet only make up about 6 percent of most science and engineering related professions.

For more information, see:

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