ChemWeb Newsletter

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New light is shed on the crystallization processes involved in constructing polymer-based photovoltaic materials, The Alchemist this week learns, while a novel framework for improving magnetic resonance imaging is also explored. In physical science a fundamental property, the size of a proton, is not what it seems and may impact on fundamental physics, chemistry, and spectroscopy alike. New work on phytochemicals reveals that compounds found in celery and various other plants may have an anti-inflammatory effect through their interaction with a specific enzyme. Remote analysis of materials using laser fluorescence triggered by the terahertz waves emitted by explosives and chemical weapons could improve homeland security. Finally, expertise in pyrolysis has led to the establishment of a startup company at Iowa State that will help develop novel liquid bio-oils.

David Lidzey of the University of Sheffield and colleagues there and at the University of Cambridge, Cardiff University and Diamond Light Source, are investigating the plastics used in a new type of low-cost solar cell with a view to improving efficiency. A key aspect of developing efficient plastic-based photovoltaic devices depends on control morphology within a thin organic semiconductor film to maximize efficiency of charge-generation and charge-extraction. The team demonstrated that the drying process and consequent crystallization occurs in three steps with the second stage being the most important in polymer rapid crystallization. Such insights could allow them to optimize the process.

Better contrast agents for magnetic resonance imaging could emerge from research into a new class of materials being developed by Wenbin Lin of the University of North Carolina at Chapel Hill. Lin and his colleagues have being developing nanoscale metal-organic frameworks (NMOFs) since 2006, which are intrinsically biodegradable, and have high porosity, which makes them ideal for targeted delivery of entrapped agents. These new agents could transport gadolinium salts to a site of interest in the body and so require less contrast agent per scan.

If the electron is the currency of chemistry, then the proton is perhaps its bank deposit box and like banking in the real world there is news that can rock their foundations. Randolf Pohl and his colleagues at the Max-Planck-Gesellschaft have been harboring just such news for several years and recently confirmed their findings regarding the size of the proton. Using muonic (as opposed to electronic) hydrogen, the team measured the charge radius of the proton with an accuracy of better than one thousandth of a femtometer. Their measurements show that the hydrogen nucleus measures 0.8418 fm. This result is beyond the margin of error on previous measurements by a factor of five. Imagine the state of international finances if banks were to see accounting errors on a similar scale. The discovery has implications for spectroscopy and the Rydberg constant, the rock on which other fundamental constants are built.

The phytochemical luteolin is found in celery, thyme, green peppers, and chamomile tea, and may have a role to play in modulating the inflammatory response in our bodies. However, little was known about a possible mechanism for this health benefit, which might even reduce the risk of cancer, heart disease and insulin resistance in some people. Now, Daniel Hwang of the Agricultural Research Service and colleagues have shown that luteolin and several other phytochemicals, quercetin, chrysin, eriodicytol, hesperetin, and naringenin, do have anti-inflammatory effects and the mechanism involves targeting the enzyme TBK1.

Terahertz technology offers the possibility of characterizing materials from a distance of up to 20 meters so allowing security staff at airports and other potentially vulnerable locations to identify explosives, chemical weapons, and even biological weapons without approaching suspicious items or people. Rensselaer Polytechnic Institute researchers have developed a new all-optical system and report details in Nature Photonics this month. The technique employs two lasers focused in the air to create a plasma that interacts with terahertz waves from an object of interest. The resulting plasma fluorescence "fingerprint" is then compared to library spectra for identification.

Chemistry graduate students at Iowa State University in Ames, with expertise in pyrolysis, have been encouraged by their professor to start a new company developing alternative fuels. The company, Avello Bioenergy Inc, is based at Iowa State's BioCentury Research Farm just west of Ames. The company is developing technology for fast pyrolysis, which rapidly heats biomass without oxygen to produce liquid "bio-oil" as a fuel and chemical feedstock, as well as bio-char, which effectively sequesters carbon dioxide and can be used as a soil improver.