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First up in The Alchemist this week is a tale of reactions where size really does matter! News of why non-smokers cough emerges at the ACS meeting in August and a new physical process has been revealed by NMR of frozen xenon atoms that could provide a chaotic link in quantum mechanics back to Newton's era. Biotech news hints at a novel way to flavor your food and Japanese chemists have made a gel that undulates like intestinal muscle. Finally, this week's award goes to AP de Silva for his highly intelligent work in the development of market-leading sensor technology.

Catalyst particle size is critical to the activity of a new gold catalyst that can oxidize hydrocarbons using oxygen gas as the only oxidant. Richard Lambert and colleagues at the University of Cambridge, UK, tested their catalyst on styrene oxidation and found that they needed no peroxides or other oxidizing additives for the reaction to proceed. The catalyst consists of 55-atom clusters of gold in an inert support. The nanoparticles are so-called 'magic number' clusters containing exactly the right number of atoms for stable geometry, which makes them ideal for catalysis. However, the overall particle size is critical to activity. Particles of 1.4 nm diameter are effective and robust but, particles larger than 2 nm are entirely inactive, the team found.

Barry Dellinger of Louisiana State University in Baton Rouge told the 236th National Meeting of the American Chemical Society about a previously unrecognized group of air pollutants that could have effects similar to substances found in tobacco smoke. The discovery could help explain the long-standing medical mystery of why non-smokers develop tobacco-related diseases like lung cancer. "Free radicals from tobacco smoke have long been suspected of having extremely harmful effects on the body," Dellinger said. "Based on our work, we now know that free radicals similar to those in cigarettes are also found in airborne fine particles and potentially can cause many of the same life-threatening conditions. This is a staggering, but not unbelievable result, when one considers all of diseases in the world that cannot currently be attributed to a specific origin."

A fundamental new physical property has been observed using nuclear magnetic resonance spectroscopy that reveals what appears to be chaotic behavior in a quantum system. While chaos is based on centuries' old Newtonian mechanics, scientists hoped to find a link with the quantum world. Now, a University of Utah study has shed light on this unsolved problem. The new study was published in Physical Review Letters by Utah's Brian Saam and colleagues and will not only provide new insights into the behavior of matter at the fundamental level but may lead to a new medical imaging technique.

Biotechnology could one day bring us such fanciful delicacies as lemon-tasting watermelon or strawberry-flavored bananas thanks to work by biochemists at The University of Texas Medical School at Houston. They have taken the first steps towards controlling the enzymes responsible for producing flavor chemicals in fruits and vegetables. Their work could be a boon for a food industry keen to find novelty especially in light of efforts to encourage everyone to eat more fresh plant produce. The research might also be used to fine-tune enzymes to produce more of a crop's natural pesticides, reducing the need for agricultural spraying. Writing in the August 20 issue of Nature C.S. Raman and colleagues explain how they could manipulate the flavor enzymes found in the popular plant model, Arabidopsis thaliana.

Japanese researchers led by Shingo Maeda at Waseda University have developed a polymer gel that can undergo peristaltic motion, without an external stimulus. They describe their invention in Angewandte Chemie and explain that the "living" gel exploits the Belousov-Zhabotinsky clock reaction. The team synthesized an ionic gel consists of cross-linked NIPAAm and ruthenium monomers. When this material is immersed in an aqueous solution containing the BZ reaction ingredients, minus the usual catalyst, the polymer network and the BZ reaction are triggered within the gel itself. The peristaltic material could be exploited in microelectromechanical systems (MEMS).

A. Prasanna "AP" de Silva is announced winner of the Royal Society of Chemistry's Sensors Award for 2008. de Silva is Chair of Organic Chemistry at Queen's University Belfast, UK. His research which focuses on molecular logic gates and most recently "intelligent" molecules is at the heart of a diagnostics system, the market-leading OPTI point-of-care blood gas/electrolyte analyzer, which has had sales amounting to $50m globally so far. The award, sponsored by GE Healthcare, is given twice yearly for chemical excellence and input into the design of novel sensors or novel applications of existing sensors.