Playing Pinball with Atoms

With nanotechnology yielding a burgeoning menagerie of microscopic pumps, motors, and other machines for potential use in medicine and industry, here is one good question: How will humans turn those devices on and off? In an advance toward giving humans that control, scientists in The Netherlands are reporting use of an external electrical signal to control an atomic-scale mechanical device that looks like the flippers on a pinball machine. Their report is scheduled for the Oct. 8 issue of ACS' monthly journal Nano Letters.

In the study, Harold J. W. Zandvliet and colleagues point out that efforts to build ever-smaller mechanical devices have made scientists recognize the difficulty of exerting control over these nanomachines, which are too tiny for any conventional on-off-switch. They describe construction and successful testing of a device, "grown" on a wafer of germanium crystal, that responds to on-off stimuli.

Researchers say the device - so tiny that billions would fit on the head of a pin - resembles the arms or flippers on a pinball machine. The signals for the arms to move back and forth come from the tip of a scanning tunneling microscope. "By precisely controlling the tip current and distance, we make two atom pairs behave like the flippers on an atomic-sized pinball machine," they state. "Our observations prove unambiguously that it is possible to control an atomic scale mechanical device using a simple electrical signal. A better understanding of similar devices can shed light on the future possibilities and opportunities for the application of atomic-scale devices."

"Playing Pinball with Atoms"

Harold J. W. Zandvliet, Ph.D.
University of Twente
MESA+ Institute for Nanotechnology.
Enschede, The Netherlands

Potentially toxic flame retardants highest in California households

In what may be an unintended consequence of efforts to make furniture safer and less flammable, residents of California have blood levels of potentially toxic flame retardants called PBDEs at levels nearly twice the national average, scientists from Massachusetts and California are reporting. Their study, the first to examine regional variations in PBDE levels in household dust and blood within the U.S., is scheduled for posting online Oct. 1 by ACS' semi-monthly journal Environmental Science & Technology.

In the new study, Ami Zota and colleagues note that PBDEs (polybrominated diphenyl ethers) are widely used as flame retardants in upholstered furniture and electronics. The materials are released into the environment as dust particles, where they can accumulate in homes as well as human blood and tissue. Although their exact effects in humans are unclear, studies in animals suggest that PBDEs may cause thyroid, developmental, and reproductive problems. Since California has among the most stringent furniture flammability standards, the researchers suspected that state residents may have higher levels of PBDE dust exposure than others in the United States.

To find out, the scientists compared data on PBDE concentrations in house dust from 49 California homes with concentrations reported from 120 Massachusetts homes and several other areas. The researchers also compared data on blood levels of PBDEs in California residents to blood levels in residents of other regions. They found that PBDE levels in California homes were four to 10 times higher than other U.S. areas. They also found that blood levels of some PBDEs were significantly higher in California residents than the rest of the country. "These findings raise concern about pending regulations and performance standards that encourage the widespread use of chemical flame retardants, which are toxic or whose safety is uncharacterized," the article states. - MTS and AD

"Elevated House Dust and Serum Concentrations of PBDEs in California: Unintended Consequences of Furniture Flammability Standards?"

Ami R. Zota, ScD
Silent Spring Institute
Newton, MA 02458

Fungus fights air pollution by removing sulfur from crude oil

Researchers in Iran are publishing what they describe as the first study on a fungus that can remove sulfur - a major source of air pollution - from crude oil more effectively than conventional refining methods. The finding could help reduce air pollution and acid rain caused by the release of sulfur components in gasoline and may help oil companies meet tougher emission standards for fuel, the scientists say. Their study is scheduled for the Oct. 1 issue of ACS' Industrial & Engineering Chemistry Research, a bi-weekly journal.

Jalal Shayegan and colleagues point out that existing processes for refining so-called "heavy," or high-sulfur, crude oil convert sulfur to hydrogen sulfide gas at high temperatures and pressures. However, they leave behind some kinds of sulfur-based compounds, which wind up in gasoline and other fuels. Scientists long have known that certain microbes can remove sulfur from oil. But nobody had tried using these microbes in so-called biodesulfurization of heavy crude oil until now, they indicate.

In the new study, the scientists describe isolation and testing of the first fungus capable of removing sulfur from heavy crude oil. The fungus, called Stachybotrys, removed 65-76 percent of the sulfur present in certain heavy crude oil from two different oil fields. The process does not need high temperatures and high-energy consumption because it occurs slightly above room temperature, they scientists note.

"Study of the First Isolated Fungus Capable of Heavy Crude Oil Biodesulfurization"

Jalal Shayegan, Ph.D.
Sharif University of Technology
Tehran, Iran

Water shortages pose challenges and opportunities for industry

Just as a credit crunch is reshaping the global economic landscape, an often-unheralded shortage of clean water is confronting business and industry with a range of profound new challenges and opportunities, according to an article scheduled for the October 6 issue of Chemical & Engineering News, ACS' weekly news magazine.

The cover story, C&EN Senior Business Editor Melody Voith, points out that big industrial companies, such as Dow Chemical, General Electric, Nalco, and Ashland, must manage day-to-day operations in ways that conserve and reuse water. Once regarded as a cheap and inexhaustible resource, clean water increasingly is in short supply around the world, Voith explains, noting that lack of clean water is "a growing risk" to industry.

"There is just no replacement for good, clean water - and it is getting harder to come by," Voith states. At the same time, companies that supply water purification and conservation technology are taking advantage of new opportunities. The articles explain how companies are investing in new technologies to meet the evolving demand for water treatment chemicals, services, and equipment.

"The Other Scarce Resource"


The American Chemical Society - the world's largest scientific society - is a nonprofit organization chartered by the U.S. Congress and a global leader in providing access to chemistry-related research through its multiple databases, peer-reviewed journals and scientific conferences. Its main offices are in Washington, D.C., and Columbus, Ohio.

Source: Michael Woods
American Chemical Society

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