New Understanding of How Carbon Nanotubes Work - New Technology

Researchers at the University of Pittsburgh have begun to understand why carbon nanotubes, which are shaped like a test tube and measure 1/20th of a millionth of an inch in diameter, will act as a sponge to soak up nearby molecules. This “molecular sponge effect” is the result of strong adsorption forces inside the nanotubes and may have applications in gas masks, environmental cleanup, the purification of chemicals, and drug delivery.

John T. Yates Jr., R.K. Mellon Professor of Chemistry and Physics in the Department of Chemistry, and J. Karl Johnson, associate professor in the Department of Chemical and Petroleum Engineering, presented their research on March 30 at the American Chemical Society’s 227th national meeting in Anaheim, Calif.

“These newly synthesized carbon nanotubes are one of the most interesting forms of the element carbon,” said Yates, director of Pitt’s Surface Science Center. “Because of their small size, the nanotubes selectively capture and retain small gas molecules in their interior. The adsorption of a molecule inside another molecule offers unique opportunities for the control of matter on the nanometer scale.”

Using infrared spectroscopy, kinetic methods, and modern theoretical methods, Yates, Johnson, and other researchers probed various molecules bound inside and outside the nanotubes. They found that molecules bound inside the nanotubes can be preferentially displaced, and have developed a theoretical understanding of this unexpected effect.

Dr. Mohr and colleagues do not claim that the data demonstrate a “causal” relationship between stressful events and MS onset or relapses, but instead suggest that these results encourage further research to define which stressful events may likely be associated with changes in MS, what biologic processes may be at work, and how people’s individual reactions to stress may come into play. They emphasize that these data should not be used to infer that persons with MS are responsible for their exacerbations, but rather should encourage further investigations into the potential link between stress and relapse.

This study contributes new insights into the existing literature concerning the possible link between stress and MS attacks, but it does not resolve the issue. Many of the studies cited had significant limitations, such as reliance on subjects’ recall of stressful events over long periods of time. This was particularly true of those studies that examined first MS attacks, where in some cases, participants had to recall stressful events that had occurred several years prior to the interview. It is possible that stress may affect the timing of exacerbations without affecting the long-term course of the disease. Moreover, very little research has addressed the biological mechanisms that might underlie a link between stress and MS. Research focusing on how stress interacts with the immune system in persons with MS may provide useful information about the disease and the role that stress may play in MS attacks.

Posted 2nd April 2004

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