News From The American Chemical Society: Feb. 20, 2008

Main Category: Biology / Biochemistry
Also Included In: Water - Air Quality / Agriculture;  Cancer / Oncology;  Public Health
Article Date: 26 Feb 2008 - 7:00 PDT

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Easing concerns about pollution from manufacture of solar cells

In a finding that could help ease concerns about the potential environmental impact of manufacturing solar cells, scientists report that the manufacture of solar cells produces far fewer air pollutants than conventional fossil fuel technologies. Their report, the first comprehensive study on the pollutants produced during the manufacture of solar cells, is scheduled for the March 15 issue of the ACS' Environmental Science & Technology, a semi-monthly publication.

Solar energy has been touted for years as a safer, cleaner alternative to burning fossil fuels to meet rising energy demands. However, environmentalists and others are increasingly concerned about the potential negative impact of solar cell (photovoltaic) technology. Manufacture of photovoltaic cells requires potentially toxic metals such as lead, mercury and cadmium and produces carbon dioxide, which contributes to global warming.

In the new study, Vasilis M. Fthenakis and colleagues gathered air pollution emissions data from 13 solar cell manufacturers in Europe and the United States from 2004-2006. The solar cells include four major commercial types: multicrystalline silicon, monocrystalline silicon, ribbon silicon, and thin-film cadmium telluride. The researchers found that producing electricity from solar cells reduces air pollutants by about 90 percent in comparison to using conventional fossil fuel technologies. - MTS

"Emissions from Photovoltaic Life Cycles"

CONTACT:
Vasilis M. Fthenakis, Ph.D.
Brookhaven National Laboratory
Upton, New York

Acid-seeking "warheads" promise safer, more effective cancer weapons

Researchers in California report development of an anti-cancer "warhead" that targets the acidic signature of tumor cells in much the same way that heat-seeking missiles seek and destroy military targets that emit heat. These acid-seeking substances are not toxic to healthy cells, and represent a new class of potentially safer, more effective anti-cancer drugs, they say. Their study is scheduled for the March 6 issue of ACS' The Journal of Physical Chemistry B, a weekly publication.

For years, scientists tried to develop anti-cancer drugs based on enediynes, a powerful class of natural, tumor-fighting agents derived from soil bacteria. However, as these substances kill both cancerous and healthy cells, their effectiveness as anti-cancer drugs is limited.

In the new study, Elfi Kraka and colleagues describe making unusual substances that become highly active only in the presence of low pH levels, or acidic environments. Since cancer cells have highly acidic environments in comparison to normal cells, compounds containing these substances - called dynemicin-amidines (DADs) - target and destroy tumor cells without affecting healthy cells, the researchers say. The substances represent "the design of the first nontoxic enediyne antitumor drugs based on the DAD principle," the report states. - MTS

"Design of a New Warhead for the Natural Enediyne Dynemicin A. An Increase of Biological Activity"

CONTACT:
Elfi Kraka, Ph.D.
University of the Pacific
Stockton, California 95211

Toward a healthier food for Fido: Corn provides promising fiber alternative

In addition to helping fill gasoline tanks with alcohol-based fuel, corn may have a new role in filling Fido's bowl with more healthful food, nutritional biochemists in Illinois are reporting. They found that corn fiber shows promise as a more economical and healthier ingredient in dog food than some of the fibers now in use. Their study is scheduled for the March 26 issue of ACS' Journal of Agricultural and Food Chemistry, a bi-weekly publication.

George Fahey and colleagues point out that the fiber content of dog food varies widely and is often of inferior quality. Many dog foods use fiber from sugar beet pulp. Corn fiber - available in large amounts as a byproduct of ethanol production - is an attractive alternative. However, researchers have little information on corn fiber's effects in dogs.

In the new study, researchers studied digestion, food intake, and fecal characteristics in dogs fed either a special food containing corn fiber or a standard food containing beet fiber. Substituting corn fiber for beet fiber "does not dramatically impact nutrient digestibility, food intake, or fecal production and characteristics," the researchers say. Corn fiber should therefore be considered a promising fiber alternative for use in dog food, they note. Previous studies suggest that corn fiber in animal food could have beneficial effects in reducing risks of obesity and diabetes. - MTS

"Chemical Composition, in Vitro Fermentation Characteristics, and in Vivo Digestibility Responses by Dogs to Select Corn Fibers"

CONTACT:
George C. Fahey, Jr., Ph.D.
University of Illinois
Urbana, Illinois 61801

New electrodes may provide safer, more powerful lithium-ion (Li-ion) batteries

Researchers in Spain and the United Kingdom are reporting development of a new electrode material that could ease concerns about the safety of those unbiquitous lithium-ion (Li-ion) batteries, while giving Li-ion batteries a power boost, according to a new study. It is scheduled for the March 11 issue of ACS' Chemistry of Materials, a bi-weekly journal.

Li-ion batteries power an increasing number of laptop computers and portable electronic devices. They are now being eyed for motor vehicles of the future. However, recent recalls of millions of Li-ion batteries due to overheating have raised safety concerns, with researchers seeking new materials to make safer, more powerful batteries.

In the new study, M. Rosa Palacín and colleagues compared the performance of Li-ion batteries made with electrodes composed of lithium nickel nitride (LiNiN) to conventional Li-ion batteries containing carbon electrodes. The new materials are more efficient than the conventional electrodes and less likely to overheat, the researchers suggest. They note that "further improvements can be envisaged by changing the reaction conditions and the processing of the electrode." - MTS

"Towards New Negative Electrode Materials for Li-Ion Batteries: Electrochemical Properties of LiNiN"

CONTACT: M. Rosa Palacín, Ph.D.
Institut de Ciència de Materials de Barcelona
Catalonia, Spain

Deadly sugar plant blast underscores need for new regulations

The explosion at a sugar refinery in Georgia earlier this month that killed nine workers underscores the need for tougher industrial safety standards regarding production of combustible dust, according to an article scheduled for the Feb. 25 issue of Chemical & Engineering News, ACS' weekly newsmagazine.

In the article, C&EN Senior Editor Jeff Johnson points out that hundreds of such dust explosions have occurred over the last 30 years. These explosions can occur without warning and can be triggered by a single spark. Most people do not realize that common substances such as sugar can become highly explosive after being processed into fine dust, whose tiny size requires less energy to ignite, the article notes. The risk grows as huge quantities of these tiny particles accumulate on floors, beams, ceilings and other areas.

Over the years, tighter federal regulations have already prevented combustible dust accidents at grain facilities. However, in light of the recent tragedy, experts feel that tougher, more uniform combustible dust standards and regulations should be expanded to cover all industries that produce combustible dust to prevent these disasters from occurring in the future, the article suggests. - MTS

"Sugar Plant Blast Rekindles Dust Debate"

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Article adapted by Medical News Today from original press release.
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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