ChemWeb Newsletter

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In our ongoing quest for fascinating chemical science, this week we learn that contrary to popular opinion hydrogen seemingly can form multicenter bonds, we also grab the long tail of bird flu proteins to find a new approach to flu drugs that might be resistant to viral resistance, and ask whether NASA's latest images prove there is flowing water on Mars? Also this week, we get microscopic with diatoms to engineer new silica structures and finally, could alternative energy sources be the bane of the environment?




Hydrogen atoms can form simultaneous bonds with as many as six other atoms, according to researchers at the University of California, Santa Barbara. Writing in December's Nature Materials, Chris Van de Walle and Anderson Janotti have demonstrated that under certain condition as can be found in metal oxides, hydrogen can bond to four or six atoms simultaneously. In zinc oxide for example, the team has found hydrogen atoms bonded to four surrounding zinc atoms. These multicenter bonds are highly stable, they say and hint at hydrogen being a substitutional dopant in oxides. The team says their discovery could have a broad range of technological applications and multi-coordinated hydrogen might also explain the electrical conductivity of metal oxides.





Researchers at Rice University and the University of Texas at Austin (UT) have investigated the structure of the long flexible tail of the influenza virus' nucleoprotein. This tail is present in all strains of influenza A including lethal bird flu, Hong Kong flu, and Spanish flu. "There is a small binding pocket for the tail loop of the protein that appears to be a promising target for a new class of antiviral drugs," explains team leader Jane Tao who is working with UT's Robert Krug, "We know from previous genetic studies that this tail loop is almost identical across strains of influenza A, so drugs that target the tail have a high potential of being effective against multiple strains, including the H5N1 [bird flu] strains." The team has found that even seemingly minor changes to the protein tail prevent it from fulfilling a key role in viral replication - linking together to form structural columns used by the virus to transmit copies of itself. New antiviral drugs that circumvent viral resistance are desperately needed if we are to ward off a flu pandemic.





Once again, NASA has got scientists parched for signs of life on other worlds ready to launch into a new debate with images that would suggest that water still flows on the Red Planet. In the same week that plans for a Moon base are announced, photographic revelations from the Mars Global Surveyor hint at the existence not only of water in whatever form but of running water. Building a base on Mars will be so much simpler if the pioneering astronauts have access to running water rather than having to use chemical means to produce the vital solvent. Skeptics are already claiming that the NASA images, which apparently show changing surface features that can only be explained by flowing water, are nothing more than wishful thinking. Others are enthusiastic that evidence of flowing water suggests an underground thermal source keeping the water liquid. The existence of liquid water and heat energy together might even hint at life on Mars.





Biomimicry is a rapidly growing area within materials science. After all, why design from scratch structures that nature has perfected through millions of years of evolution? But, understanding exactly how living organisms carry out their often microscopic construction projects is key to emulating their skill set. Now, researchers at the Georgia Institute of Technology have found a way to understand how microscopic algae, diatoms, build their complex and patterned cell walls. "Diatoms are nature's most gifted nanotechnologists," says team leader Nils Kröger, "We want to learn how diatom cell walls are produced because human technology can't make something that intricate by self-assembly processes and under ambient conditions." The team has developed a technique to genetically engineer diatoms that allows them to insert mutated or foreign genes and so push the mutant diatoms to create novel silica structures.





Alternative sources of petroleum fuels, such as tar sands, may cause more environmental problems than they solve, according to a report from the UK's Institute of Physics. In the report, published in the journal Environmental Research Letters, Alex Farrell of the University of California, Berkeley claims that "Liquid fuels for transportation are increasingly coming from a wide range of sources other than conventional petroleum. We call this the oil transition and we conclude that the environmental risks associated with this transition are much bigger than the risk to a country's economy or the security of their fuel supply." Tar sands are currently one of the biggest unconventional sources for petroleum. Bitumen, a very think mixture of organic liquids, is mined from the tar sands. "We have calculated that production of fuels from low-quality and synthetic petroleum, such as tar sands, could have greenhouse gas emissions 30%-70% greater than the emissions from conventional petrol," adds Farrell.