ChemWeb Newsletter

Not a subscriber? Join now.September 12, 2006

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Can planetary giants make metallic water? That's a question answered theoretically by US scientists in this week's Alchemist, we also learn why mussels are not as happy as clams thanks to Prozac, what makes organic semiconductors light up and the possibility of powering your mp3 player with your beach umbrella. Also in this week's news distillate, uranium-munching bacteria have the mettle to construct nanoscopic platinum particles. Finally, digestion on a grand scale could be releasing five times as much methane into the atmosphere above Siberian lakes.




Could a gaseous giant be strong enough to pressurize water into a metallic state? That's the suggestion of a new theoretical study of water crystallites that could form under marginally less extreme conditions of temperature and pressure than previously thought. On the ice giant planet Neptune and the gas giant Jupiter, temperatures of 4000 K and pressures of 100 gigapascals might exist, which the new study by Thomas Mattsson of Sandia National Laboratory suggests are enough to push water into a metallic, cubic ice phase. In this phase, the oxygen atoms are locked in place, but the hydrogens are more freely mobile providing a medium for electrical conduction.





You'd think mussels in a bed bathed with water containing Prozac would be as happy as clams…well it seems the opposite holds true. Rebecca Heltsley of the National Institute of Standards and Technology, in Charleston, South Carolina, told the 232nd national meeting of the American Chemical Society, that mussels are anything but happy. She and her colleagues studied the ecotoxicological effects of Prozac (fluoxetine) on freshwater mussels and have found that the drug triggers the females release their larvae prematurely. About 70% of the almost 300 species of freshwater mussels native to North America are extinct, endangered or declining, she said. "The presence of Prozac and similar drugs in US rivers and streams has likely compounded the problem," Heltsley said. "It's a big concern because freshwater mussels are such an imperiled group."





George Malliaras and colleagues at Cornell University have developed a new type of organic semiconductor device that not only displays electroluminescence but also acts as a photovoltaic cell. The device, based on an anthracene derivative and a ruthenium complex is the first example of an ionic junction in this field. The new device displays improved performance and could be fabricated into thin, flexible sheets for a variety of applications. For instance, woven into a beach umbrella, the material could generate electricity to power an mp3 player or to charge up a mobile phone. The material could also be incorporated into clothing or flexible displays.





Researchers in Germany have found a way to control the growth of nanoscopic catalyst particles using bacteria that live in uranium mines. Bacillus sphaericus JG-A12 has evolved a protective protein layer to protect it from extreme environments by aggregating toxic metals with which it comes into contact. Now, Katrin Pollmann of the Forschungszentrum Rossendorf in Dresden and her colleagues have found a way to exploit this period protein layer to grow nanoparticles of platinum. The Pt clusters have a well-defined structure and preliminary tests hint at much greater catalytic activity than conventional platinum catalysts. The next step is to see whether they can use the same approach to make gold catalyst particles too.





Siberians lakes are "burping" up five times as much methane as scientists previously estimated. Katey Walter of the University of Alaska Fairbanks and colleagues have made the first accurate estimates of emissions of methane from frozen bubbles of the gas trapped in lakes across the Siberian permafrost. A unique type of permafrost, yedoma, which contains an estimated 500 gigatons of carbon, largely in the form of ancient dead plant material, which has been locked up since the end of the last ice age. Now, it is being released into the bottom of lakes, providing microbes with a banquet from which they burp out methane as a byproduct of decomposition, Walter says. "We realized that our previous estimates were missing a very large and important component of lake emissions," she adds, the emissions could provide a positive greenhouse gas feedback loop. As temperatures rise, so more yedoma melts into the lakes, giving the microbes more to feed on and resulting in an even bigger burp.