ChemWeb Newsletter

Not a subscriber? Join now.April 23, 2007


This week's grant amounts to almost half a million dollars and will be received by chemical engineer Thomas Epps at the University of Delaware. In the world of chemistry news the economics of photovoltaic cells fail to stack up, shedding light on stretched DNA, and concerns about the concern surrounding estrogenic bisphenol A. Also this week we discuss a new chemistry database tool literally on the web and the serendipitous discovery of the world's smallest LEDs.

Bisphenol A is a synthetic compound with weak estrogenic properties and has been linked to concerns over reproduction and gender problems in wildlife. Most of the 1-2 billion kilograms produced annually in the US alone is in polycarbonate food containers, baby bottles, refillable water containers, CDs, and liners for food and drink cans. Opponents of its use claim that studies funded by chemical producers fail to consider low-dose, but chronic exposure on public health. Now, University of Missouri biologist Frederick vom Saal points to several reasons why low-dose studies have failed to find adverse effects. Writing in C&EN, Bette Hileman suggests that vom Saal's opinions ought to be taken into account and that "it is especially important that an unbiased panel with no conflicts of interest and with a detailed knowledge of the field evaluate the literature on BPA." Such a panel could consider the weight of evidence in regard to adverse effects and choose only valid studies that avoid vom Saal's concerns from which to draw conclusions.

A Google for chemistry has been sadly lacking from the roster of Favorites and Bookmarks on every laboratory computer. ChemSpider, launched at the recent ACS meeting, however, could remedy that situation. The site makes accessible and available a database of more than 10 million chemical structures and pertinent information, comprising academic, open access, and commercial databases, including PubChem and ChEBI. Search is possible using molecular structure, chemical synonym, Smiles strings and InChI. The system's designers claim that the site aggregates and indexes chemical structures and associated information into a single searchable repository for free. Chemspider thus overcomes one of the major problems facing chemists investigating the existence of particular structures, by providing access to even commercial databases that would otherwise fall below the structure search radar.

Electrospun fibers made by scientists at Cornell University gave off an orange glow during experimentation leading the multidisciplinary team to consider the possibility of making nanoscopic LEDs. The ruthenium-based fibers are 200 nanometers wide and so smaller than the wavelength of the light they emit. Such smallscale light sources could be used in sensing and microscopy as well as the more mundane world of cellphone and computer flat-panel displays.

Chemical engineering Prof Thomas Epps at the University of Delaware is set to receive a $460k grant as part of the NSF's Faculty Early Career Development Award scheme. The award is given to a young researcher whose career path is likely to make them an academic leader very quickly. The grant will fund Epps' research into block copolymers. His work on these self-assembling materials comprising two distinct polymer chains is heading towards next-generation high-performance materials that are likely to be used in efficient fuel cells and chemical-resistant, yet breathable materials.

A complete cost-benefit analysis of photovoltaic solar cells, published in the International Journal of Environmental Technology and Management by researchers in Italy, suggests that their cost far outweighs the financial savings one might expect from reduced electricity costs. On the other hand, the cradle to grave analysis carried out by Giacomo Bizzarri of the University of Ferrara and Gianluca Morini of the University of Bologna, suggests that over the whole lifetime of PV panels from manufacture to disposal the carbon footprint and energy costs are lower than the amount renewable energy produced. The balance will tip in favor of solar cells should the cost of electricity generated using fossil fuels rise three or four times today's price.

UV light can affect the properties of DNA detrimentally, unraveling the ability of the double helix to replicate and to interact with the transcriptional machinery for making proteins. One phenomenon that has not been studied in detail until now is the changes in elasticity of DNA under UV light. Piotr Marszalek and his colleagues at Duke University have now stretched DNA to its limits. They used a scanning probe microscope to do the stretching and their single-molecule force spectroscopic measurements show how crosslinks formed in DNA by UV irradiation alter the molecule's elasticity directly. Even small changes in elasticity can severely affect DNA's elasticity and so hinder its normal functions. "These are the first measurements that establish a relationship between DNA nanomechanics and damage," explains Marszalek. He adds that the research paves the way for using stretch-release force spectroscopy measurements in DNA diagnostics.