Stories of modern science ... from UPI

RESEARCHERS MEASURE NANOSPHERES

The first measurements of hardness on individual silicon nanospheres have been made by University of Minnesota researchers. The study shows nanosphere hardness falls between the conventional hardness of sapphire and diamond, among the hardest known materials. Measuring nanoparticle properties could help scientists design low-cost superhard materials for nanoscale building blocks. The research team first devised a way to produce defect-free silicon nanospheres, in which the silicon spheres condensed out of a stream of silicon tetrachloride vapor onto a sapphire surface. Sphere defects reduce the hardness by acting as sites for flow or fracture. The hardness was measured by squeezing individual particles between a diamond-tipped probe and the sapphire. The researchers found the smaller the sphere, the harder it was.

PREDICTING MUTATIONS IN DRUG RESISTANCE

Scientists at Whitehead Institute for Biomedical Research have developed a screen to identify genetic mutations that cause resistance to anti-cancer drugs -- even before patients are treated. They worked on identifying mutations that cause patients with chronic myeloid leukemia to become resistant to Gleevec, the cancer-fighting drug that targets the protein produced by BCR/ABL, the gene that causes this rare form of leukemia. Recombinant DNA methods were used to randomly mutate the BCR/ABL gene to mimic potential variations. The mutated genes then were transferred into millions of mouse blood cells and exposed to Gleevec. While most cells succumbed to the drug, some of the cells with specific variations thrived. A catalogue of mutations, researchers said, could help physicians examine patients who've relapsed because of resistance to Gleevec and pinpoint which of the 112 mutations they've found is causing problems -- or better yet, detect the presence of a mutation before the patient relapses.

CREATING A ENVIRONMENTALLY FRIENDLY TIRE

Dutch researchers are working on a more environmentally friendly car tire using mixable silica and rubber. The two were combined in a ratio that produced a tire with a low rolling resistance, which means a lower fuel use for the vehicle. Louis Reuvekamp from the University of Twente mixed silica and rubber using organosilane as a coupling agent. Tire manufacturers normally use carbon black instead of silica to strengthen the tire rubber. Experiments showed a temperature of at least 130 degrees Celsius was needed for the coupling agent to react with silica but the reaction could not rise above 150 degrees -- the temperature at which the rubber vulcanizes and becomes too hard for further processing. The researchers discovered zinc oxide disrupts the coupling but is essential to the tire, therefore it was added after the coupling reaction.

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(EDITORS: For more information on NANOSPHERES, contact David Hart, (703) 292-8070, or e-mail dhart@nsf.gov. For MUTATIONS, Kelli Whitlock, (617) 258-9183 or whitlock@wi.mit.edu, and for TIRES, Nalinie Moerlie, +31 70 3440713, or press@nwo.nl)