David Bradley – Page 333

Open access chemical interview

The latest issue of the Reactive Reports chemistry news site is now live. In it, I discuss various advances in the chemical sciences including weighty issue of trans fat that has butter lovers everywhere declaring, “I told you so!” Also in issue 56, I report on the basic approach to chemotherapy that side-steps the need for a magic bullet and find out how NASA has lit a fuse under the planetary carbon debate.

Our reactive profile this month is Will Griffiths. Griffiths a chemist by training like me opted out of the lab early in his career with the aim of applying his chemical knowledge and expertise through an altogether different medium. He is now investing his time and energy in developing the ChemRefer.com website, which offers chemists every quick and open access to the free full-text chemistry literature. You can use this search tool via the Chemspy Toolbox or download the Chemrefer toolbar.

Inorganic gas puzzle

A postgraduate student has posted a research problem on sci.chem.analytical, which Sciencebase’s chemically aware readers might be interested in puzzling over.

The student seems to have discovered a new inorganic gas.

Apparently, he heated a zeolite which consists Analcime, feldspar and silica to 500 Celsius. X-ray fluorescence shows the presence of Si Al K Ca Na S Ti and Fe. When the heated material is dissolved in HCl, a gas is evolved with the following properties (summarized by M Farooq on CHEMED-L):

(a) It smells like ammonia

(b) It gives a precipitate with calcium hydroxide which re-dissolves in HCl

(These properties would suggest carbon dioxide, but….)

(d) It can be collected over water and has an ammoniacal smell but is not as irritating as ammonia

(e) The gas does not react with silver chloride in solution (unlike ammonia) but can colorize silver nitrate solution (goes from colorless to weak yellow, similar to iron(III) ions in solution)

It might be a gaseous hydride and is almost certainly not an organic compound as all would be destroyed at 500 Celsius. Arsine impuritues are unlikely as the X-ray fluorescence did not reveal arsenic.

So, what is it?

Schizophrenia drugs warning for journalists

Many years ago, when I was writing on a weekly basis for New Scientist, in fact long before the magazine even had a web presence, I wrote a short news item about a new class of drugs for treating the symptoms schizophrenia.

Within days of that issue hitting the shelves I received several letters from desperate readers asking where they could get hold of the drug. Unfortunately, it was very much in the experimental stages and as far as I am aware the compound in question never did make it to market. A lesson learned.

A press release from the American Chemical Society announces yet another development in the drug discovery process for schizophrenia. At first, I was reluctant to follow it up, but even though once again the discovery is preliminary and not yet at the pharmaceutical marketing stage, it is an interesting enough lead to warrant a mention.

Indeed, scientists are reporting progress toward treating a long-neglected group of symptoms that impair the functioning of people with schizophrenia. This chronic, highly debilitating disease affects 3 million people in the United States. Schizophrenia involves “positive” symptoms (hallucinations and delusions), “negative” symptoms (apathy and withdrawal) and cognitive symptoms (such as difficulty in filtering out unimportant sensory information).

Despite major advances in drug therapy for the positive and negative symptoms, cognitive symptoms – which appear in 85 percent of patients – go largely untreated today. A team of researchers at Pfizer, including Bruce Rogers, report the discovery of a potential drug for schizophrenia’s cognitive symptoms. Their study will appear in the June 29 issue of the Journal of Medicinal Chemistry.

The new compound, PHA-543,613, is believed to mimic nicotine’s biochemical effects in the brain in enhancing cognition. More than 80 percent of people with schizophrenia are heavy smokers, and scientists believe smoking may be a form of self-medication for the disease. PHA-543,613 improved cognitive functioning in animal tests, including object recognition and P50 gating – a common test to measure auditory information processing. The researchalso provides additional support for the hypothesis that such compounds represent a novel, potential pharmacotherapy to treat the cognitive deficits in schizophrenia. One has been shown in separate reports to improve cognitive functioning in healthy human volunteers.

You can find the paper through its DOI – 10.1021/jm0602413 – here. Just cut and paste the number into the yellow science toolbox on that page and click the DOI go button. If you’d like to add this toolbox to your website, please grab the simple javascript and slot it into a suitable position on the page. The team at the Usefulchem blog are already using the companion science search box.

Prehistoric greenhouse

Looking at prehistoric climatic change may provide new insights into predicted near-future climate. New results for a greenhouse effect that occurred during the late Cretaceous some 75-90 million years ago suggest that very different mechanisms controlled the climate then and that these may be applicable in the near future, perhaps forcing a revision of received wisdom regarding climate change.

Sascha Floegel and colleagues at the IFM-GEOMAR in Kiel, Germany working with Thomas Wagner of the University of Newcastle upon Tyne, England, have investigated the causal relationships and feedback loops between the tropics and higher latitudes and have identified a “climate kitchen” in a world with an average global temperature between five and 9 degree Celsius higher than today.

More…

Lead in China’s children

Researchers in Beijing have carried out a meta-analysis of AAS and ICP-MS results published during 1994-2004 to obtain a countrywide picture of how the level of lead in children’s blood is changing and how where they live effects their exposure to this toxic element.

Perhaps predictably, the team found that those children living in urban or industrial regions had much higher levels of lead than those living in rural areas. The figures they reviewed also contrast sharply with the children’s western counterparts who have much lower lead levels on average. The issue is a matter of significant public health importance for China, the researchers say.

Exposure to lead can affect the central nervous system and affect learning ability and growth. It is ubiquitous in the environment and can be absorbed in the human body by inhalation and ingestion from a variety of sources such as contaminated water, soil, food, lead-containing products such as paint and from vehicle exhausts in areas where tetra-ethyl lead is still used as engine an anti-knocking agent.

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The really small print

Microscopic printing techniques could be used to make the next generation of electronic components for large-area displays with higher definition and covering much larger areas than is currently possible with even the best displays today. The technology could also lead to versatile sensors for a range of applications from the environmental to the medical, all at dramatically reduced costs compared to current micromanufacturing technology.

Researchers can already carry out microcontact printing on metal surfaces a few tens of square centimetres in size using microcontact printing and etching. However, while this is a fairly straightforward approach on smaller areas, researchers would prefer to be able to develop a much simpler method applicable even to large-scale production for bigger displays and sensor arrays. Now, a team at Philips Research in Eindhoven in the Netherlands has developed what they call a universally applicable “ink” for microcontact printing.

Anaerobics class

A QSPR (quantitative structure-property relationship) study of the anaerobic biodegradation of chlorophenols could lead to an improvement in the disposal of these potentially carcinogenic industrial waste products.

Youzhi Dai, Dasen Yang, Fei Zhu, Lanyan Wu, Xiangzheng Yang, and Jianhua Li of the Department of Environmental Engineering, at Xiangtan University, People’s Republic of China have based their analysis on quantum chemical and physicochemical descriptors, using partial least squares analysis to obtain a good prediction of the QSPR for the disappearance rate constant (logK) of chlorophenols (CPs) in an anaerobic microbial culture.

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Sonic laser

The ultrasound equivalent of a laser could lead to important new discoveries in materials science by providing researchers with a non-destructive way to detect even the subtlest of changes, such as phase transitions deep in their samples. Now, researchers at the University of Illinois at Urbana-Champaign and at the University of Missouri-Rolla have built just such an ultrasound analogue of the laser – the uaser, pronounced way-zer.

Light amplification by stimulated emission of radiation devices, lasers, are well known, but a sonic analogue had until now not been developed. Richard Weaver and his colleagues set out to change that and to develop a device that would induce ultrasound amplification by stimulated emission of radiation to produce coherent ultrasonic waves of a single frequency. “A sonic laser has been possible for some time now,” Weaver told us, “our method could have been done earlier. I tend to think it wasn’t for two reasons: first no-one saw an application and second few people are expert at both laser physics and ultrasonics.”

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Gates and Windows

It always seemed odd that a guy called Gates would fill his life with windows but today Microsoft Corp. announced that as of summer 2008 chairman Bill Gates will drop out of his transition day-to-day role in the company and begin to focus on his global health and education work through the Bill & Melinda Gates Foundation. Apparently, it’s going to take two years for the “transition” to happen, which is about right really, and no doubt they’ll give the process a code name like BigBone, and then when the marketing people get a hold of it they’ll change it to Scheista. It’s nice that he’s going to go through this transition at a time when the next version of Windows will be hitting the torrent networks.

True blue electric blue

polymer-led-mullen Wide angle X-ray scattering, photoluminescence, polarizing optical microscopy, differential calorimetry, and dielectric spectroscopy have been used to study the optical properties of a range of blue-light emitting organic compounds. The mechanism of the self-assembly of these oligoindenofluorenes up to the polymer, their thermal properties, and associated molecular dynamics also reveal important clues about their behaviour and potential for applications in organic light-emitting diodes (OLEDS) and other devices.

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