ChemWeb Newsletter

Not a subscriber? Join now.April 15, 2011

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Medical probes for metastatic cancer are in the news this week, as are sensor films for checking the freshness of vacuum-packed food without breaking the seal. Polymer chemists have developed their stereocontrol and PCBs are in abundance of the coast of West Africa. In physical chemistry, a new structure could allow scientists to get much closer to absolute zero than ever before. Finally, a major award from AstraZeneca for Canadian chemist André Beauchemin.




A new strategy to build molecular probes to visualize, measure, and learn about the activities of protease enzymes on the surface of cancer cells has been developed by US chemical engineers. The probes will have important applications in understanding how cancer metastasizes, or spreads, in the body. "Tumor metastasis is widely regarded as the cause of death for cancer patients," explains team leader Patrick Daugherty of the University of California Santa Barbara. Metastasis is mediated by proteases and so understanding their form and function is critical to understanding cancer more fully. The approach to making the probes is fairly general and might also be used in studying rheumatoid arthritis and perhaps other conditions.





A sensor film that can be incorporated into food packaging could alert consumers when a particular perishable product has spoiled. The sensor film developed by the Fraunhofer Research Institution for Modular Solid State Technologies EMFT in Munich responds, with a color change, to the presence of biogenic amines. These compounds are formed as fish and meat decay and help give rise to the unpleasant odor of rotten food, but in a hermetically sealed or vacuum-packed food there is no way to smell whether the food is fresh without opening the package.





Controlling the order in which monomers are linked together to form a polymer is often relatively straightforward but ensuring the building blocks are in the correct orientation is a different matter. Now, Kyoko Nozaki and a team from the University of Tokyo have made the first poly(propylene carbonate) with polymer chains built up in the form of a gradient of two stereochemically different propylene building blocks. This polymer is usually used to bind the components of biodegradable plastics. The new approach to controlling its construction could open up a new wave of polymers for a range of applications allowing polymer chemists to tailor their fine properties for specific purposes.





PCBs off West Africa High levels of polychlorinated biphenyls (PCBs) have been detected along the coasts of West Africa, the scientists who discovered the pollutants suggest that they could come from the illegal dumping of waste or from an enormous ship breaking yard in Mauritania. PCBs were used years as dielectric fluids in electrical transformers, condensers and as coolants for various devices. However, production was banned in the US in 1979 because of toxicity and carcinogenicity concerns and because they are persistent environmental pollutants. They have also been banned since 2001 under the Stockholm Convention on Persistent Organic Compounds. Rosalinda Gioia of Lancaster University, UK, and colleagues have identified PCBs at concentrations of 10 to 360 picograms per cubic meter in some countries of West Africa, such as Gambia and Ivory Coast, and all along this coast.





Avoiding the use of rare and costly helium-3 in low-temperature science may soon be possible thanks to preliminary work in developing a molecular chiller. Euan Brechin from the University of Edinburgh, UK, Keith Murray from Monash University in Australia and Marco Evangelisti from the University of Zaragoza in Spain and their colleagues have designed a molecule based on gadolinium and copper, which can be cooled to a few millikelvin using the high magneto-carolic effect. This effect occurs when the magnetic field is removed from a ferromagnetic material causing a massive drop in temperature. The key to success is finding a material with many spin-aligned unpaired electrons.





The AstraZeneca Award in Chemistry for 2011 goes to André Beauchemin, associate professor in the University of Ottawa's Department of Chemistry for his outstanding contributions to the field of synthetic organic chemistry. Beauchemin will receive an unrestricted grant of $100,000 over two years. Beauchemin's research focuses on structural elements incorporating nitrogen atoms into pharmaceuticals, common to more than 90% of all drugs. This research award will provide the resources to develop these processes, in collaboration with medicinal chemists at AstraZeneca Canada.