ChemWeb Newsletter

Not a subscriber? Join now.June 11, 2008

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First up this week, is an award for pioneering work in mass spectrometry and the study of molecules colliding with surfaces. A way to create the thinnest polyethylene plastic bag ever has been devised by a team in Germany, while Australian researchers are hoping to defeat HIV by thickening the protective keratin layer of the penis using the female hormone estrogen. The Alchemist also learns that the Brits are turning to waste oil from that wondrous delicacy Fish & Chips to power up their cars. Also in this week's issue, Japanese chemists have synthesized what at first site looks to be a hexavalent carbon compound. Finally, with the long summer months stretching ahead of those of us in the Northern Hemisphere, The Alchemist cracks open a tinny and discovers that researchers in Venezuela have uncovered the secret to making beer last longer - add a little poison.




The Biemann award given by the American Society for Mass Spectrometry this year goes to Julia Laskin of the Pacific Northwest National Laboratory. The international award recognizes her contribution to our understanding of the activation, fragmentation and deposition of large molecules when they collide with surfaces. Laskin accepted the award at the ASMS annual conference June 3 in Denver, Colorado. As well as receiving this prestigious award she delivered a lecture on her research to almost 7000 conference delegates.





Stefan Mecking and colleagues at the University of Konstanz, Germany, have developed a new method to produce wafer-thin polymer films that avoids the high temperatures and organic solvents of conventional approaches. The team instead carried out the catalytic polymerization of ethylene using nickel complexes to produce aqueous dispersions of crystalline polymer particles. They then droppered this dispersion on to a glass slide and spun it at 2000 revolutions per minute, to spin coat the substrate. Excess liquid flies off, leaving behind a film a mere 50 nanometers thick. The new approach precludes the need for toxic reagents and can product highly uniform films for further investigations.





An application of topical estrogen to the penis over a two-week period could inhibit the spread of HIV by thickening the natural keratin layer on the skin. The epithelium of the human penis is richly supplied with estrogen receptors, explains Andrew Pask of the University of Melbourne, suggesting it could respond to topical estrogen, but unlike the vagina has only a very thin protective keratin layer. Pask suggests that in countries and cultures where circumcision is uncommon thickening this keratin layer could reduce the ability of HIV to penetrate the epidermis of the foreskin. HIV is one of the greatest health crises the world has ever seen, and affects over 40 million people worldwide. "We now have found a new avenue to possibly prevent HIV infection of the penis," says Pask.





That staple of British haute cuisine - "fish & chips" - produces a lot of waste used vegetable oil across the nation. Now, a group known as the Low Impact Living Initiative (LILI) is organizing courses to teach drivers, car-fleet owners, and others how to convert this waste product into biodiesel. With vehicle fuel prices continually on the rise and heavy taxation, a gallon of diesel fuel costs well above the equivalent of $10 in the UK. Brits could see huge fuel cost savings by switching to biodiesel and there is no tax to pay on biodiesel production up to about 660 gallons per person. The only downsides are that the exhaust fumes may take on a fishy aroma and all those extra deep-fried fish & chips the Brits will have to eat could bulk up the obesity epidemic.





Might chemists have at last synthesized a hexavalent carbon compound? The X-ray structure and computational analysis of a compound with a central allenic carbon atom flanked by four oxygens would suggest so. Torahiko Yamaguchi of the University of Hiroshima, Japan, and colleagues crowded out an allenic carbon with two hefty sulphur-containing ligands based on reducing thioxanthone and took an X-ray snapshot. The sulphur ligands take up the allenic bonds north and south of the carbon atom with four oxygens then ringing the carbon to complete the octahedral arrangement. It certainly looks like those C to O distances are short enough to be bonds, and may not be simply jammed together. But, while there may be some kind of stabilizing force between the carbon and oxygens and the distances are well within van der Waals radii, the best that one can say at this point is that the carbon is probably hexacoordinate but probably not hexavalent.





Blocking the Maillard reaction could be key to extending the shelf-life of light beers and lagers, according to scientists in Venezuela. Adriana Bravo and colleagues at the Empresas Polar brewery and colleagues at the Simón Bolívar University in Caracas explain that previously brewers assumed the Maillard browning reaction between amino acids and reducing sugars was unimportant to beer production after the initial heating steps. However, Bravo's team has now shown that degradation products of the reaction continue to accumulate in beer even as it sits on the shelf, at far lower temperatures than those used during brewing. The team identified alpha-dicarbonyl intermediates of the Maillard reaction at between 20 and 30 Celsius using NMR spectroscopy and mass spectrometry. The team has experimented with various inhibitors of this process, although they are yet to find one that is non-toxic.