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All mammals produce a normal version of prion protein, which in altered form becomes the dreaded infectious agent responsible for mad cow disease and related conditions in humans and other animals. But why? Until now, prion protein's function in the body has been a mystery.
Gerd Multhaup and colleagues at the Free University of Berlin now are reporting conclusive evidence that prion protein helps regulate levels of copper and manganese inside body cells. Their study is scheduled for publication in the June 13 issue of Biochemistry.
Multhaup's group used laboratory experiments to show that normal prion protein plays a role in metabolism of copper and manganese, helping to maintain optimal levels of those two metals. They propose that prion protein may be part of a system that protects cells heavily exposed to copper, manganese or both metals. An increase in manganese levels, they report, favors formation of the altered prion protein that causes fatal neurological diseases.
The findings, they state, hint that high levels of manganese in the food chain may increase the risk of mad cow disease, Creutzfeldt-Jakob Disease, and other prion afflictions. The researchers note that clusters of these diseases have been reported in areas of Colorado, Iceland and Slovakia with high levels of manganese in the soil.
Green roofs have been getting a lot of ink lately as an ecological solution to the concrete-and-glass jungle of cities. Roofs with plants growing in a light-weight soil substitute are supposed to reap multiple benefits — aside from making cities more attractive. Those benefits include improving air quality and reducing air conditioning bills.
Fact or fad?
The first life cycle assessment (LCA) quantifying the benefits of green roofs concludes that replacing a conventional flat roof with a green roof does have definite benefits. Susana Saiz-Alcazar and colleagues at the University of Toronto and Environment Canada completed the study, scheduled for publication July 1 in Environmental Science & Technology.
Their 50-year LCA calculated the benefits of a green roof established on an eight-story residential building in a warm climate. Annual energy savings were just over 1 percent, with a 6 percent reduction in summer cooling load. Replacing the flat roof with a green roof reduced overall environmental impacts, including energy use, of the building by 1 percent to 5 percent. The authors noted that some, but not all, of the benefits, may be partially possible by simply painting the roof white (to reflect sunlight) and adding a little more insulation.
Journal: Environmental Science & Technology
Journal Article: “Comparative Life Cycle Assessment of Standard and Green Roofs”
If people were as:
• Strong as an ant they could lift 20 times their own body weight
• Fleet of foot as a flea, they could jump the length of a football field
• Good at harvesting water from the air as Namib beetles, they could drink in the driest deserts
Michael F. Rubner, Robert Cohen and colleagues at the Massachusetts Institute of Technology are reporting a technological leap in biomimetic research toward the Namib beetle's feat. Biomimetic research strives to imitate the wonders of Mother Nature. Rubner's group has developed a synthetic surface that mimics the water-harvesting abilities of the Namib beetle.
The backs on these desert insects have hydrophilic (water-attracting) bumps alternating with hydrophobic (water-repelling) valleys. The bumps collect water droplets from morning fogs and the valleys funnel water toward the beetle's mouth, almost like beads of rain on a freshly waxed car.
Rubner and Cohen’s groups have developed a surface structure that mimics the hydrophilic/hydrophobic patterning of the beetle. “Potential applications of such surfaces include water harvesting surfaces for military personnel deployed in deserts, controlled drug release coatings, open-air microchannel devices and lab-on-chip devices,” they state in a report scheduled for the June 14 issue of Nano Letters.
Single-walled nanotubes (SWCNTs) top the list of nanomaterials likely to find important commercial, industrial and medical applications. Made from pure carbon, SWCNTs are hollow molecular cylinders. Each nanotube is just one nanometer in diameter (10,000 times smaller than the width of a human hair). SWCNTs have unusual properties and may be used in drug delivery systems, electronic displays, new super textiles and other products.
That potential has made SWCNTs a focus of concerns about human and environmental toxicity. Toxicology tests on SWCNTs, however, have puzzled and perplexed scientists. Some tests indicate that SWCNTs are highly toxic to cells; others show no trace of toxicity.
A study scheduled for publication in the June 14 edition of Nano Letters offers an explanation. H. F. Krug and colleagues at the Institute of Toxicology and Genetics at the Research Center Karlsruhe in Germany report that traditional toxicity assays may not produce valid results for nanomaterials.
“We demonstrate here that the uncritical publication of toxicity data for these new nanomaterials may present false positive results, which in fact can turn against this new technology,” the scientists state. They caution scientists not to rely on the outcome of a single toxicity assay. Krug also cites an urgent need for development of standardized toxicological assays that present an accurate picture of the health risks of nanomaterials like SWCNTs.
An arcane pharmaceutical industry practice termed the “exclusionary payment” has quietly re-emerged, forcing consumers to keep paying high prices for brand name drugs that could be marketed as less-expensive generics. In the late 1990s, courts ruled that exclusionary payments constituted illegal restraints of trade. Now however, courts are allowing them again, with three payments made in 2005 and seven so far in 2006.
An article by Bette Hileman in the May 22 issue of Chemical & Engineering News describes the resurgence and impact of exclusionary payments. In a typical scenario, a generic drug company seeks U. S. Food and Drug Administration permission to market a generic version of a brand name drug. The brand name manufacturer then files a patent infringement suit. If the brand name manufacturer fears loosing the suit, it pays the generic drug company to delay marketing its product for several years.
C&EN, the weekly newsmagazine of the American Chemical Society, discusses exclusionary payments that have blocked consumer access to generic versions of several popular brand name drugs.
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.