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The Alchemist gets a radical view of the realm of silicon this week, finds out how resistance might be resisted in cancer, sheds light on a new anti-counterfeit ink, and takes a trip into deep time to learn of a truly ancient and enormous asteroid and has a look at the feathery friends acting as chemists. Finally, a Bader award for iodine chemistry and microreactors.
A rare mixed valence disilicon hydride has been generated by Alexander Filippou and colleagues at the University of Bonn, Germany. These types of species are known to exist fleetingly during chemical vapor deposition (CVD) processes, such as those used to make semiconductors for photovoltaic devices, for instance. Their transient existence makes them difficult to study despite their importance in the final quality of a given product. Intriguingly, one atom exists in the 1 valency state while the other is in the 0 state, Filippou's team found, having trapped the radical between two N-heterocyclic carbenes.
US researchers have developed a putative cancer drug that works against tumors that have developed resistance to conventional chemotherapy. Kevan Shokat at the University of California, San Francisco and Neal Rosen at Memorial Sloan Kettering Cancer Center and their colleagues have used a new strategy to block mTOR, a protein known to help drive growth in many tumors. In animal experiments, the drug - Rapalink, which combines a first and second generation inhibitor to provide two binding points - reduced the size of tumors that are resistant to earlier-generation mTOR inhibitors.
A new type of ink that has three levels of photochemical activity could be used to create difficult to copy "watermarks" for money, certificates and other sensitive documents. Hengwei Lin at the Ningbo Institute of Materials Technology & Engineering of Chinese Academy of Sciences, the University of Chongqing, and Southeast University in Nanjing and colleagues have demonstrated an ink that can generate light through three different mechanisms - photoluminescence, two-photon luminescence (up-conversion photoluminescence), and phosphorescence. The potential of all three phenomena in a single substance could be a very useful anti-counterfeit measure.
Tiny glass beads found in Western Australia hint at the impact of an enormous asteroid 3.46 billion years ago. Andrew Glikson from The Australian National University (ANU) and colleagues identified the spherules in ancient sea floor sediments although their location does not point to an impact site for the 20-30 kilometer-wide rock because millions of years of plate tectonic movement and volcanic activity have erased any trace of a crater. "The impact would have triggered earthquakes orders of magnitude greater than terrestrial earthquakes," says Glikson, "it would have caused huge tsunami and would have made cliffs crumble and the material from the impact would have spread worldwide."
Red is the color, chemistry is the game when it comes to avian crossbreeds. Two studies have investigated how some birds can synthesize red ketocarotenoids from yellow carotenoids. One experiment has homed in on the cytochrome P450 enzymes used by a breed of bird produced a century ago by crossing yellow canaries and red siskins. The second study compared common zebra finches, which have a distinctive red beak and mutant zebra finches with yellow beaks to identify the P450 genes. The genetic discovery raises new questions about the role of red pigmentation in birds, which is important for sexual and territorial activity but those enzymes are more commonly associated with detoxification processes in the liver. "Our results, which link a detoxification gene to carotenoid metabolism, may shed new light on the debated honesty of carotenoid-based signals," says one of the researchers, Staffan Andersson of the University of Gothenburg, Sweden.
This year's prestigious Bader Award from the Royal Society of Chemistry has been won by Thomas Wirth a professor of chemistry at Cardiff University, UK. The award recognizes Wirthï¿½s work on iodine reagents for organic chemistry that precluded the need for some toxic materials. "I feel very honored by this award and take this as an indication that basic research on iodine chemistry and a more applied focus using microreactor technology for flow synthesis is of interest to academic as well as industrial research. This award also acknowledges the dedicated work of my co-workers and collaborators and encourages us to further explore and drive chemistry in these areas," said Wirth.