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ACS News Service Weekly PressPac: Wed Jul 19 16:42:03 EDT 2006
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News Items in this Edition
The discovery of a new electrolyte often sparks major advances in batteries, solar cells and other energy storage and conversion devices. An electrolyte is a substance, such as hydrosulphuric acid in a car battery, that contains free ions and conducts electricity. New electrolytes fostered everything from the venerable NiCd battery to the latest lithium-ion polymer batteries and dye sensitized solar cell (DSSC).
Scientists in China are reporting development of a new aluminum iodide (AlI3) battery. It uses aluminum and iodine as anode and cathode respectively, and the in situ formation of aluminum iodide as electrolyte. In a report scheduled for the July 19 issue of the Journal of the American Chemical Society, this new electrolyte also is used to make a DSSC. Sometimes termed Graetzel cells— after their inventor, Michael Graetzel — DSSCs are among today’s most promising solar energy conversion devices.
The researchers say that AlI3 has major advantages over existing technology. The aluminum-iodine system is inexpensive, for instance, and based on the cheap and environmentally benign iodine-ion primary battery. The new DSSC is about as efficient (5.9 percent) as an existing DSSC that requires ingredients that are expensive and toxic.
A heart drug that went into clinical trials in the 1990s has become the linchpin for efforts to develop a medication to treat female sexual arousal disorder (FSAD), researchers are reporting. An estimated 40 percent of women have FSAD or another form of female sexual dysfunction, the difficulty or inability to find satisfaction in sexual expression.
Compounds that sustain the activity of vasoactive intestinal peptide (VIP) are a major target of drug research efforts. VIP controls blood flow to the vagina, and decreased blood flow is believed to be one factor in female sexual dysfunction. VIP is degraded in the body by several enzymes, including an enzyme called NEP. Blocking NEP thus allows VIP to continue working.
David Pryde and colleagues at Pfizer Global Research and Development in the United Kingdom began work with Candoxatril, a powerful NEP inhibitor tested in the 1990s for chronic heart failure. By re-engineering Candoxatril's molecular structure, they developed a compound with the key actions needed for an FSAD drug.
The new compound blocks NEP, takes effect rapidly, and continues having an effect for a relatively short time. “The compound demonstrates excellent efficacy in a rabbit model of sexual arousal and was expected to be similarly efficacious in humans,” the researchers state in the current issue [July 13] of the ACS Journal of Medicinal Chemistry. The compound is undergoing clinical evaluation as a potential treatment for FSAD.
Scientists are reporting an advance toward development of a long-sought alternative to the traditional ways of closing incisions in the eye after cataract surgery. Mark W. Grinstaff and colleagues have synthesized and tested a new biocompatible adhesive gel that seals eye incisions quickly with the strength to keep the incisions sealed. Their report is scheduled for the current [July 19] issue of ACS Bioconjugate Chemistry.
In about 11 million cataract operations performed worldwide each year, surgeons either stitch the tiny incisions with nylon sutures, or allow the incisions to self-seal. Both techniques have drawbacks. Sutures carry a risk of infection, inflammation, and unwanted formation of new blood vessels. Self-sealing carries a risk of infection and leakage of fluid from inside the eye, the scientists note.
Grinstaff and colleagues previously developed and tested a gel suitable for repairing scratches and other acute corneal injuries. In the new research, they developed and tested on enucleated human eyeballs an adhesive that lasts longer for cornea surgery. “The hydrogel can be used in conjunction with a reduced number of sutures to successfully fasten a corneal transplant and secure the wound interface,” they report.
Researchers have confirmed that soils and sediments in New Orleans contained elevated arsenic and lead concentrations following Hurricane Katrina and have shown that levels of those toxic metals were not affected by later flooding from Hurricane Rita. Their follow-up sampling of multiple sites in the hurricane-ravaged city found that levels of 24 of the 27 metals were below U. S. Environmental Protection Agency (EPA) limits. The findings are reported in an article scheduled for the August 15 issue of ACS Environmental Science & Technology. Levels of arsenic, lead and iron exceeded the limits.
“We confirmed that the majority of metals were not present at concentrations that suggest a widespread and immediate need for concern,” said the research team, which was headed by George P. Cobb. “However, arsenic and lead did frequently exceed USEPA criteria for assessing human health risks. This poses difficult policy decisions for the regulatory community.”
The new study both confirms and expands on earlier findings in ways that the researchers describe as important. For instance, the new results suggest that flooding after Hurricane Rita neither redistributed toxic metals in some areas of the city nor washed them away. As plans for rebuilding move ahead, more focused sampling should be done at the neighborhood level, the study recommends, to identify specific hot spots in need of capping or other measures to prevent dangerous exposures.
With the U. S. Agency for International Development (AID) embracing DDT to battle malaria in Africa, a classic debate is reemerging over the benefits and risks of a pesticide hailed as a lifesaver by some and condemned as an environmental menace by others, according to an article scheduled for the July 24 issue of Chemical & Engineering News.
USAID announced last year that it was funding the use of DDT for spraying the inside walls of houses if a country requests it and if an environmental assessment indicates the insecticide will be safe and effective, C&EN senior editor Bette Hileman explains in the article. The decision comes at a time when new studies suggest that prenatal exposure to DDT may retard child development and lead to preterm birth. In addition, there is concern that DDT may end up on crops, endangering wildlife and beneficial insects.
DDT, however, may be the cheapest and most effective way to reduce malaria’s toll in Africa, Hileman writes, noting that malaria kills one child every 30 seconds. The U. S. National Academy of Sciences estimated that DDT’s use in the past, before a 1970s-era ban in the developed world, saved 500 million lives. The article describes the trade-offs involve in resumption of DDT in malaria-control programs, and the new research reports about DDT’s adverse health effects.
- Green Chemistry Blog
Green bullets? Green sneakers? How about the U. S. debut of a green insect repellent? Check out the ACS News Service’s news blog for those and other news-grabbers from the 10th annual Green Chemistry & Engineering Conference, held last month in Washington, D.C. Green chemistry is a far-ranging effort to reduce the environmental impact of the chemical enterprise. It focuses on developing and using technologies that are cleaner, smarter, less costly and more sustainable than approaches traditionally used in chemistry and chemical engineering.
Mark Your Calendars
September 10-14 is one of the year’s biggest and most influential scientific conferences – the 232nd ACS national meeting in beautiful San Francisco.
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.