By reworking a theory first proposed by physicists in the 1920s, the researchers discovered a new way to predict important characteristics of a new material before it's been created. The new formula allows computers to model the properties of a material up to 100,000 times faster than previously possible and vastly expands the range of properties scientists can study.
"The equation scientists were using before was inefficient and consumed huge amounts of computing power, so we were limited to modeling only a few hundred atoms of a perfect material," said Emily Carter, the engineering professor who led the project.
"But most materials aren't perfect," said Carter, the Arthur W. Marks '19 Professor of Mechanical and Aerospace Engineering and Applied and Computational Mathematics. "Important properties are actually determined by the flaws, but to understand those you need to look at thousands or tens of thousands of atoms so the defects are included. Using this new equation, we've been able to model up to a million atoms, so we get closer to the real properties of a substance."
By offering a panoramic view of how substances behave in the real world, the theory gives scientists a tool for developing materials that can be used for designing new technologies. Car frames made from lighter, strong metal alloys, for instance, might make vehicles more energy efficient, and smaller, faster electronic devices might be produced using nanowires with diameters tens of thousands of times smaller than that of a human hair.
Erich Feldmeier on 24 Aug 12""We probably have underestimated the role our microbial flora play in modulating disease risk," says Daniel Rader, a heart disease specialist at the University of Pennsylvania School of Medicine. Rader, who was not involved in the study, says that gut bacteria may not be as big a factor in causing heart disease as diabetes or smoking, but could be important in tipping some people toward sickness. Researchers led by Stanley Hazen, a cardiologist at the Cleveland Clinic, didn't start out to study gut bacteria. In fact, says Hazen, he had "no clue - zero," that intestinal microbes were involved in heart disease. "I'd never even considered it or thought of the concept." Hazen and his colleagues compared blood plasma from healthy people to plasma from people who had had heart attacks, strokes or died to see if substances in the blood could predict who is in danger from heart disease. The researchers found 18 small molecules associated with fat buildup in the arteries. One of the best predictors turned out to be a byproduct made when gut bacteria break down a fat called choline (also known as lecithin). The more of this byproduct, called trimethylamine N-oxide or TMAO, a person or mouse has in the blood, the higher the risk of getting heart disease, the researchers found. Gut bacteria are actually middlemen in TMAO production. The microbes convert lecithin to a gas that smells like rotten fish. Then an enzyme in the liver changes the foul-smelling gas to TMAO."
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