| Number 157
| May 3, 2004
New technique determines interfacial structure
Researchers at DOE's Argonne National Laboratory have taken the guesswork out of interfacial structure determination. The researchers have directly visualized, in three-dimensions, ion site distributions at the mineral-water interface using a technique called X-ray standing wave (XSW) imaging. Their finding demonstrates a new capability for revealing complex reactions. XSW, in contrast to X-ray crystallography, measures both the amplitude and phase information that completely describes the molecular-scale structure of interest. The XSW imaging approach allows scientists to streamline the tedious process of structure determination. With XSW imaging, data acquisition and analysis can be completed in less than 24 hours. Previously, surface structure determination would take weeks or months to complete.
[Donna Jones Pelkie, 630/252-5501;
“Beefed up” plant-dwelling bacteria boost phytoremediation
| Root of poplar tree at 1000x shows colonization by pollutant-degrading bacteria (green).
Using plants to soak up and degrade environmental pollutants, a strategy known as phytoremediation, can be more successful in theory than in practice. The accumulated pollutants or their metabolites sometimes kill the plants or evaporate via the leaves back into the atmosphere. But scientists at DOE's Brookhaven Lab think they've found a way to improve the process: Transfer genes from pollutant-degrading bacteria into bacteria residing in the plants so the resident bacteria can help the plants break down the pollutants. In a recent test study, plants inoculated with the “beefed-up” bacteria survived in toluene-contaminated soil and increased the degradation of the pollutant.
[Karen McNulty Walsh, 631/344-8350;
Zapping polyester for soil resistant clothes
Laser-cut fabric has long been a popular fashion statement, but by aiming light at the surface of fabric, rather than through it, scientists at DOE's Jefferson Lab have found they can make polyester garments soil resistant. Manufacturers currently use chemical treatments to give fabrics soil resistance. But these treatments may yield environmentally unfriendly waste and add significantly to a garment's price. Using a deep UV lamp, College of William and Mary and JLab collaborators have developed a cost-effective method to change polyester's surface chemistry. The treatment doesn't affect fabric's shape, feel or look.
[Kandice Carter, 757/269-7263;
Rites of spring have carbon impact
Spring's lush green lawns and hot pink shoes contribute at least in a small way to the world's total carbon picture, say researchers at DOE's Oak Ridge National Laboratory. Indeed, the latest fashions on Fifth Avenue and fertilizers that help homeowners achieve that "barefoot" lawn have their associated carbon dioxide costs. A recent analysis shows that nearly 22,000 manufacturers in the textile and apparel industry emitted about 12 million tons of carbon dioxide in 1998. And fertilizing one acre of lawn at the recommended rate of 137 pounds per acre results in 405 pounds of carbon dioxide-equivalent emissions from the production, transportation and application of the fertilizer.
[Ron Walli; 865/576-0226;
Methuselah enzymes: SEN and the art of molecule maintenancei
Single-enzyme nanoparticles, or SENs, left, and their thinner cousins, right, remain active for up to 143 days, thanks to their protective caging. (J.B. Kim, Pacific Northwest National Laboratory.)
Enzymes, the workhorses of chemical reactions in cells, lead short and brutal lives. They cleave and assemble proteins and metabolize compounds
for a few hours, and then they are spent. This sad fact of nature has
limited the possibilities of harnessing enzymes as catalytic tools outside the cell, in uses that range from biosensing to toxic waste cleanup. To increase the enzyme's longevity and versatility, a team at DOE's Pacific Northwest National Laboratory has caged single enzymes to create a new class of catalysts called SENs, or single
nanoparticles. The nanostructure protects the catalyst, allowing it to remain active for five months instead of hours. PNNL researchers say the principal concept can be used with many water-soluble enzymes.
[Bill Cannon, 509-375-3732;
The Road to Lindau
For Deborah Zorn, the road to Lindau , Germany, and the 54th International Convention of Nobel Laureates began in childhood. The Ames Laboratory graduate student from Lincoln , Neb. , says she rarely missed an airing of “ Newton 's Apple” and almost always took summer science classes in Lincoln 's Bright Lights program.
Zorn is one of 25 top, young researchers from the United States who will receive full support from DOE's Office of Science to attend the June 27-July 2 Lindau meeting. There, she will interact with Nobel Laureates and network with student participants from around the world.
“Debbie is interested in all aspects of science and is fearless and successful in attacking problems,” says Mark Gordon, Zorn's major professor and director of Ames Laboratory's Applied Mathematics and Computational Sciences Program.
Zorn studies theoretical and computational chemistry at Iowa State University . In one DOE research project, she is creating and implementing theoretical and computational models to ease the identification of properties in new materials being developed for catalytic systems.
Another of Zorn's DOE projects uses quantum mechanics and molecular mechanics methods to study the behavior of certain metals on a silicon surface. The work may lead to atomic wires one atom wide for nanotechnology applications.
Zorn credits her father with encouraging her interest in science. “He instilled an interest in science and an appreciation for math in me for which I will always be grateful,” she says.
Science is Zorn's passion, but she's also an art enthusiast and an accomplished golfer, and was an NCAA division III All-American and Academic All-American Athlete.
“I like to think of myself as a creative person,” says Zorn. “Whether it's science, art or sports, it's all about problem solving. I enjoy taking bigger problems and breaking them down until they are similar to something I've seen before and that I can solve.”
Submitted by DOE's
Ames National Laboratory