ChemWeb Newsletter

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The Alchemist travels back billions of years to the dawn of life this week to learn how aspartic acid may be the crystal Eve, the mother of all chirality while heading back to the future also discovers how biology and nanotechnology might be fused to produce new metamaterials for a range of medical and analytical technologies. Banned scent compounds turn up in children's toys, we hear while US chemists have built a molecule that bites its own tail to trap smaller molecules within. In environmental news, the recent volcanic activity that grounded thousands of travelers to and from Northern Europe may not have the environmental impact some observers have suggested. Finally, chemistry is the word as Microsoft launches a CML, chemical markup language, add-in for its well-known word processing application.




Julius Rebek, Jr. and Fabien Durola of The Scripps Research Institute, La Jolla, USA, have constructed a molecular tail devourer, which they have named an ouroborand after the Greek ouroboros. The system functions as a molecular machine, that can encapsulate a smaller molecule but has a built-in switch that regulates access to the cavity. A switchable rotor, a bipyridyl unit, on its edge acts as a zinc-activated access control, In the presence of zinc ions, this rotates so that it opens entry to the cavity and can allow smaller molecules inside. Remove the zinc and the molecule once again bites its own tail.





Iceland's glacially embedded volcano, Eyjafjallajokull, may have grounded planes across Europe for the best part of a week because the risk to jet engines of flying through its cloud of ash, but the total amounts of ash and greenhouse gases emitted by the volcano are a mere fraction, about 1%, of those emitted by Mount Pinatubo back in 1991. Mt. Pinatubo in The Philippines produced a plume of ash 21 miles high and 250 miles wide within two hours and in just two weeks had spread across the globe producing an average temperature drop of 0.5 degrees Celsius. Eyjafjallajokull's release of a mere 150 million tons of ash, dust and greenhouse gases is therefore unlikely to have any significant impact on global climate.





The creator of the Windows operating system and a well-known Office suite of programs, Microsoft, has entered the chemical world with the launch of a free add-on for its word processing application that lets users insert chemical labels, formulas, and two-dimensional structures into a document. Chem4Word, which is in the beta testing phase, is based on Chemical Markup Language (CML), which means meta data underlies labels, formulas, and structures. Cambridge University's Peter Murray-Rust, co-creator of CML and the new add-in, points out that it is not yet available for Apple Macintosh computers, but is open source, so anyone with the technical know-how could "port" the add-on for Mac Word or Open Office.





Chirality in biology has puzzled chemists for decades. Why is it that life mainly uses just one chiral form of amino acids and other biomolecules? A new clue offers a potentially crystal clear answer as scientists at the National Central University in Taiwan, have identified a crystal that may have first stimulated the chiral bias in biology billions of years ago. Tu Lee and Yu Kun Lin point out that conditions on the primordial Earth held an equal chance of forming the same amounts of left-handed and right-handed amino acids. They have demonstrated that left-handed aspartic acid crystals predominate in reaction conditions similar to those that might have existed at the dawn of life through preferential crystallization.





Steven Lenhert now at The Florida State University, working with colleagues at Germany's University of Muenster and the Karlsruhe Institute of Technology, have extended so-called dip-pen nanolithography to use an atomic force microscope to lay down precise patterns of biofunctional lipid multilayers of defined height between 5 and 100 nanometres. The multilayers applied to a pre-prepared surface lead to readily characterized nano metamaterials with a wide range of applications in lab-on-a-chip science, including the possibility of developing consumer diagnostics devices that could be built into smart phones.





Scented toys are growing in popularity, but a recent investigation to test for the emission of fragrance allergens from such toys using headspace solid-phase microextraction gas chromatography-mass spectrometry has revealed that several contain substances banned in the European Union on health and safety grounds. 55 banned fragrances can be present at up to just 100 micrograms per gram if their presence in the toy is technically unavoidable. However, scientists in the Department of Product Safety at the Federal Institute for Risk Assessment in Berlin, Germany, have found high levels of the plasticizers diethyl phthalate and diisobutyl adipate, in various toys tested as well as measurable amounts of permitted fragrances. More worryingly, however, they detected three banned substances of which benyzl benzoate was well above the 100 microgram tolerance limit.