The Alchemist Newsletter: October 14, 2008

Morbid tales of post-mortem intervals caught The Alchemist's eye this week as US researchers develop an informatics approach to determining time of death of skeletal remains. Elsewhere, nanotube and polymer chemists have found a way to out-gecko the gecko having developed a model of the geckos' hairy feet that is ten times as sticky. Adhering with the theme of sticking, European researchers have found a way to tether prions to a model cell membrane that could open up new research into diseases such as Creutzfeldt-Jakob. In environmental news, recent insights into dust from the Sahara could improve our understanding of climate change. Sand of another kind is being used in an entirely different way, by British researchers to protect a new type of thermometer used to measure the 3000 Kelvin temperatures of an explosion. Finally, a biological discovery once more wins the Nobel Prize for Chemistry with three international scientists sharing the award for the discovery and development of green fluorescent protein.

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Skeletal analysis

Researchers at Baylor University, in Waco, Texas, have developed a cheminformatics method for correlating spectra with the time course of protein and water loss from skeletal remains. Their approach is relatively simple and could cut the time taken to determine the "post-mortem interval" of bones. The team says their combined regression models can be as accurate at providing a date of death between four and nine days for bones that are up to 90 days old. “In perfect conditions in the laboratory, the method looks very encouraging,” says team leader Kenneth Busch. The approach could greatly assist crime scene investigators and forensic scientists especially in places where heat and humidity are high and the flesh weak.

Baylor Researchers Use Chemometric Method to Determine Age of Skeletal Remains

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How to out-gecko the gecko

The race to find a material as "sticky" as a gecko's foot could soon be over as stronger and more practical materials are simultaneously reported in the latest issue of Science by a team based at four US institutions. Scientists have long been interested in the ability of gecko lizards to scurry up walls and cling to ceilings by their toes. The creatures owe this amazing ability to microscopic branched elastic hairs in their toes that take advantage of atomic-scale attractive forces to grip surfaces and support surprisingly heavy loads. Now, researchers have found a way to mimic those hairy gecko feet using polymers or carbon nanotubes. The new material has a gripping almost three times stronger than the previous record and ten times as sticky as the gecko foot itself.

Gecko Foot Adhesive Gets Stronger, Directional Gripping

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Tethered prions

The spongiform encephalopathies, which include the human neurodegenerative diseases Creutzfeldt–Jakob disease, mad cow disease, and scrapie in sheep, are caused by an errant protein known as a prion. Prions can anchor themselves to cell membranes via a glycosylphosphatidylinositol, GPI, group and then transform normal healthy proteins into copies of themselves. Now, Christian Becker at the TU Munich, Germany, and Peter Seeberger at the ETH Zurich, Switzerland, and their colleagues have built a synthesized a GPI-anchored prion in the laboratory, which they say could help researchers model the activity of prions. Their anchoring technique will also be generally applicable to tethering other proteins involved in unrelated diseases.

Tracking Down the Cause of Mad Cow Disease

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Dusty desert finding

The Sahara Desert is a powerful emitter of atmospheric dust, which travels to the Amazon and Caribbean regions, including Florida, also reaching the North of Europe, Israel and even the Himalaya. Such mineral dust grains contain iron, calcium, sulfur and sometimes phosphorus, and can fertilize the soil, forests and plankton of the oceans, lakes and seas across the globe. Now, soil scientists at the University of Granada, Spain have discovered and characterized a new type of atmospheric aerosol they call 'iberulites'. Team leader Rafael Delgado says the discovery could be useful in studying atmospheric reactions and in understanding the hydrodynamic model of the earth's water cycle.

Discovery of a type of aerosol from Sahara which will be useful to study climate change

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Measuring a big bang

A bomb-proof thermometer has been developed by British scientists. Gavin Sutton and colleagues at the National Physical Laboratory near London says that the new high-speed thermometer can measure the temperature within an explosion without being damaged by the detonation. The shockwave, heat, soot and debris from an explosion can damage normal thermometers but thermocouple type thermometers are too slow to react to allow scientists to model explosions accurately. However, an optical fiber 400 micrometers across, protected from the blast by a sand-packed steel tube with one open end can detect thermal radiation at four wavelengths taking measurements 50000 times a second and has been calibrated to 3000 Kelvin. The lab tests involved temperatures above this temperature and the only damage done was a small amount soot off the end of the optic fiber says Sutton. "We easily removed that with alcohol and a Q-tip," he says.

Bomb-proof Thermometer To Measure Heat Of Explosions Developed

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Glowing prize for Nobel chemists

This year's Nobel Prize in Chemistry rewards the initial discovery of green fluorescent protein from the beautiful jellyfish, Aequorea victoria in 1962 by Osamu Shimomura, now at the Marine Biological Laboratory (MBL), Woods Hole, Massachusetts, Martin Chalfie of Columbia University, New York, and Roger Tsien, of the University of California, San Diego, La Jolla, for their development of GFP as an important tagging tool in the biosciences. DNA technology now allows researchers to connect GFP to interesting, but otherwise invisible, proteins, making them glow green under certain conditions and so providing a way to look deep inside the cell and to develop applications that exploit the fluorescence as a visible marker for specific activity in a range of species from bacteria to pigs.

The Nobel Prize in Chemistry 2008

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-- David Bradley, Science Journalist