Spectroscopy – Page 13 – David Bradley

Cotton bud art conservation

Cotton Bud Sampling A simple Q tip is all it takes to grab a microscopic sample from a work of art for laboratory testing, according to Canadian analytical chemists. They’ve used the approach to sample darkening pigments from an ancient map and from a piece of modern art as proof of principle.

They then used a range of standard spectroscopic techniques to identify components of the pigments. This particular work will provide art conservators with important clues as to how to prevent further degradation of these important cultural objects, but more widely the successful demonstration of cotton bud sampling shows that analysis of artworks needn’t be invasive and destructive.

I interviewed research leader Douglas Goltz of the University of Winnipeg who told me that, “For conservators this approach gives them another tool for identifying pigments…Certainly not every museum or art gallery has immediate access to sophisticated techniques, such as XRF – this approach can be used by anyone. The Q-tip can be carried easily and then stored for later analysis of metals in the lab.”

Read on at SpectroscopyNOW.com

RFID for chemicals

RFID for molecules A new type of radio frequency identification (RFID) sensor for gaseous molecules has been created based on a standard RFID tag coated with a chemically sensitive film at low cost. The use of multivariate analysis allows these new RFID sensors to be used to identify and quantify vapours important to industrial, in health, law enforcement, and of security applications.

Radislav Potyrailo and William Morris of the Materials Analysis and Chemical Sciences Technology at General Electric Global Research Center, in Niskayuna, New York, explain the benefits of their new technology in a forthcoming issue of the journal Analytical Chemistry. “Distributed sensor networks are critical for numerous applications such as monitoring of transport of pollution plumes across the perimeters of industrial plants, leak detection from storage tanks, health monitoring of buildings, large-area tracking of contamination sources in natural water supplies, and spatially resolved combinatorial screening of materials,” they explain.

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Scratchy and itchy

Researchers are only just begin to scratch the surface of the brain with functional MRI. Now, a study of perception in both allergen- and histamine-induced itch has revealed how different parts of the brain are activated in response to stimulation from each type.

Allergens, such as pollen and dust, and histamine released by allergy cells as a result of activation by foods, drugs, or infection often lead to a vicious itch?scratch cycle as any allergy sufferer will tell you. However, researchers at Oxford University have demonstrated that the brain responds differently to itchiness caused by allergens and histamine.

Siri Leknes, Susanna Bantick, Richard Wise, and Irene Tracey at Oxford have worked with Carolyn Willis and John Wilkinson of the Department of Dermatology, at Amersham Hospital to try to understand the nature of itch? cycle with a view to improving outcomes for allergy sufferers and people with certain chronic skin conditions.

Read on in the latest science news round-up from David Bradley on spectroscopynow.com

Being particular about DNA

Surface-enhanced Raman spectra (SERS) of DNA and RNA mononucleotides can be detected with high sensitivity, according to UK researchers. Using citrate-reduced silver colloidal nanoparticles aggregated with magnesium sulfate instead of the more common halide ions, reduces inappropriate enhancements and produces spectra that are sufficiently different to allow each to be distinguished.

“The main advantage of our SERS approach is that it allows direct label-free identification of mononucleotides in aqueous solution,” Steven Bell, Director of the Innovative Molecular Materials Group, at Queen’s University Belfast, explains, “There is no requirement for labels because the Raman signals of each of the mononucleotides are intrinsically different due to the differences in their chemical structures.” He adds that spectra can be obtained at ten nanograms per millilitre. “We were working with large samples but reducing the sampling volume to a few microlitres would move the sample down to tens of picograms,” he says.

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Nervous scoop

An action shot of the protein Scp1, which plays a crucial role in the development of the nervous system has been obtained using crystallography by researchers in the US. Their structure could provide drug designers with a template for creating small molecule inhibitors of this protein that would be useful in neurological research.

Joseph Noel and Samuel Pfaff of the Salk Institute for Biological Studies and colleagues there and at the University of California, San Diego (UCSD) and The Scripps Research Institute, La Jolla explain that a network of signalling molecules controls embryonic stem cell differentiation. Controlling the controllers might allow scientists to nudge embryonic stem cells into becoming specific cell types, which would be useful in basic research and for potential therapies.

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Analytical techniques clean up diesel

Raman spectroscopy, X-ray diffraction, and electron microscopy could help diesel engine components manufacturers meet tough new emissions regulations, according to researchers at Oak Ridge National Laboratory’s High Temperature Materials Laboratory (HTML).

The techniques can provide detailed characterizations of materials and allow components to be tested for heat and stress effects more effectively as part of the industry’s preparation for new emissions mandates that come into effect in the US in 2007. Under the new laws, a 90% reduction of nitrogen oxide, NOx, and particulates from diesel vehicles will be required.

“Environmental Protection Agency regulations are pushing emissions control technology very hard,” explains Arvid Pasto, director of the HTML, “so that engine and emissions control equipment manufacturers require access to very sophisticated tools to develop this technology. Fortunately, our user facilities are well equipped to help them.”

Diesel engine-maker Cummins, for instance, has used HTML’s analytical capabilities to better understand the properties of materials used in exhaust after-treatment systems. In addition to studying how catalysts can be adversely affected by sulfur and other gaseous exhaust components, Cummins and HTML have worked together to characterize the fatigue life of cordierite diesel soot filters, which remove more than 98% of particulate emissions from diesel exhaust. These exhaust after-treatment devices are critical to meeting upcoming emissions requirements.

Another company Industrial Ceramic Solutions, of Knoxville, Tennessee, used HTML’s scanning electron microscope facility to analyse material being developed for ceramic-fibre diesel particulate exhaust filters. The original material did not function as well as competing products and had a tendency to crack. The tests revealed that the fabrication process was to blame and ICS has modified its process to improve the product.

‘The sophisticated electron microscopy at HTML allowed our small business to literally look inside of the ceramic fiber filter media at thousands of times magnification,’ said Richard Nixdorf, ICS president and CEO. ‘This information led ICS to solutions that eliminated micro-cracking and moved our filter-media strength far beyond what the diesel exhaust filter application demanded.

Influenza’s long tail

A long protein tail found in all influenza A virus raises the possibility of novel drugs that can grab on to it and stop the virus in its tracks. The protein tail is present in common human influenza A which kills thousands of people every year as well as rare forms such as bird flu.

US scientists used crystallography to study the long flexible tail of the influenza virus’ nucleoprotein. They found that even seemingly insignificant changes to the structure of this protein tail prevent it from fulfilling a key role in viral replication. That is, they prevent them from linking together to form structural columns used by the virus to transmit copies of itself.

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Flu mechanics

With the holiday season almost upon us, that means only one thing, flu is also on its way and if the scaremongers are to be believed the long-forewarned bird flu epidemic might follow in its wake any time soon.

Now, US researchers have put to work the 15-ton 900 MHz NMR machine at Florida State U to help them figure out the mechanics of infection by influenza A virus. The common human form of the disease already kills several hundred thousand people every year, and forecasters predict the emergence of a human transmissible form of avian influenza could kill millions more.

“Using NMR helps us build a blueprint for a virus’s mechanics of survival,” explains FSU’s Tim Cross, “The more detailed the blueprint, the better our chances of developing drugs capable of destroying it.” The researchers have found that the virus’ protein coat contains channels that control various biochemical reactions crucial to viral infection and replication.

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Highly strung

Stradivarius violin Infrared and NMR spectroscopy have possibly revealed one of the great secrets of the violin makers Stradivari and Guarneri del Gesu – they used chemical wood preservatives to help preserve their instruments and to improve the tonal quality. The discovery could help modern-day violin makers emulate more closely the properties of irreplaceable violins from the 18th Century and well as providing music conservationists with new insights on how to best preserve the antique instruments.

Joseph Nagyvary at Texas A&M University, in College Station, and colleagues, reveal in a brief communication to the journal Nature how the maple wood used by the celebrated craftsmen could have been chemically processed before the violin makers even began crafting the wood. The researchers have analysed in detail the organic matter from small samples of shavings retrieved from the interiors of five antique instruments during repairs.

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Expanding proteins

Expanding proteins A new study reveals that the static snapshots recorded in protein crystallography may be missing the bigger picture. Investigations of a bacterial protein using cryomicroscopy shows the protein in a balloon-like mode previously hidden from sold state studies. The discovery suggests that techniques complementary to X-ray crystallography are essential if molecular biology is to gain a complete understanding of protein structure.

Steven Ludtke, assistant professor of biochemistry and molecular biology and co-director of the National Center for Macromolecular Imaging at Baylor College of Medicine and colleagues Dong-Hua Chen and Wah Chiu there and Jiu-Li Song and David Chuang at The University of Texas Southwestern Medical Center in Dallas, studied a mutant protein and came to this perhaps not so startling conclusion. The protein GroEL chaperones misfolded proteins and nudges them into their active folded state in the cell. Protein misfolding is implicated in a number of neurodegenerative diseases, such as Alzheimer’s disease and the prion diseases including Creutzfeldt-Jakob disease.

The full story is now available at SpectroscopyNOW