ChemWeb Newsletter

Not a subscriber? Join now.December 20, 2005


This issue, The Alchemist finds cleaning up lead-laden dust is just as easy with household cleaners as with specialist chemicals, ponders the issue of whether there can be smoke without fire, and nanofoam for tackling fire risk. Finally, we keep our chips cool with carbon nanotubes and find out that there may be no need for cannabis in treating pain and depression.

Researchers at Strathclyde University in Glasgow, Scotland, have developed a fire-retardant foam rubber based on clay that could save countless lives. The modified polyurethane contains nanoscale particles of clay that prevent the material from disintegrating during a blaze and prevent the fire from spreading. The composite sidesteps the need for high levels of toxic and environmentally harmful bromates and organophosphates explain the developers John Liggat and Richard Pethrick. The invention comes at a time when stringent EU regulations are demanding action to reduce use of the current chemicals to a minimum.

Electronics manufacturer Fujitsu has discovered how to keep silicon chips cool using carbon nanotubes. The company's researchers found it could grow on a silicon wafer a heat-conducting forest of carbon nanotubes, each just 15 micrometers in length, using an iron catalyst. The novel heat sink profile matches the pattern of electrode "bumps" on the base of the chip through which it connects to the motherboard. The nanotube heatsinks were able to efficiently cool high-frequency power amplifier chips of the kind used in mobile phone base-station equipment. The power of such chips are limited by how fast heat can be conducted away to prevent the device melting. The nanotubes could allow the chips to be run even faster without overheating.

Gabriella Gobbi of the University of Montréal and colleagues have demonstrated the effects of a new drug on the brain and mood. The compound, URB597, raises cannabinoid levels and so could represent a safer alternative to smoking cannabis for the treatment of pain in multiple sclerosis and other disorders as well as anxiety and depression. This is the first time that a compound that increases endocannabinoids has been shown to have a positive effect on mood. "The results were similar to the effect we might expect from the use of commonly prescribed antidepressants, which are effective on only around 30% of the population," explains Gobbi. "Our discovery strengthens the case for URB597 as a safer, non-addictive, non-psychotropic alternative to cannabis for the treatment of pain and depression and provides hope for the development of an alternate line of antidepressants, with a wider range of effectiveness."

Roger Lewis of the Saint Louis University School of Public Health and his colleagues have demonstrated that everyday household detergents can remove lead-contaminated dust from household surfaces just as effectively as more expensive high-phosphate detergents and lead-specific cleaning products. Of the approximately 100 million housing units in the United States, about 24 million have significant levels of lead in dust, soil and paint, according to the US Department of Housing and Urban Development (HUD). The US Government guidelines recommend lead-specific cleaning detergents for removal of such lead from hard surfaces, such as floors and window areas, but Lewis' results reported in a forthcoming issue of Environmental Science & Technology, suggest that they may be unnecessary.

A new sensor that can distinguish between smoke from a fire and cigarette smoke has been developed by a consortium of European scientists. "Currently, 90% of regular fire alarms are false," explains project coordinator Florence Daniault, "Nevertheless, the emergency services must investigate every alarm logged, which is enormously inefficient." The new detector is based on sensitive conducting polymers, the electrical resistance of which changes depending on the presence of different surrounding gases. An array of polymers was incorporated into the device, which produces a characteristic response depending on which gases are present - whether from a "real" fire or cigarette smoke.