Good Chemistry

"All theoretical chemistry is really physics," Richard Feynman once joked, "and all theoretical chemists know it." Maybe not so funny for the chemists, coming from the mouth of a famed physicist. But Feynman had a point: chemistry, the study of atomic matter (and perhaps all that matters, some theorists might say), overlaps with nearly every other scientific discipline.

For this reason, when you get a bunch of chemists together--as happened last week in Washington, D.C., for the annual meeting of the American Chemical Society (ACS)--many interesting insights, discoveries and budding technologies come out, covering a vast range of interests. Reports can include everything from more effective drugs and smaller circuitry to safer foods and cleaner cars--from the profound to the practical.

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The latest ACS meeting was no exception. Researchers from around the world presented more than 5,500 papers. On the medical front, scientists from the University of Colorado described a puttylike, biodegradable polymer that can help knit broken bones back together, minimizing the need for invasive surgery to remove metal plates and pins.

Chinese chemists from Nankai University revealed possible molecular mechanisms shared by the protein plaques that mark Alzheimer's disease and Creutzfeldt-Jakob disease (the human equivalent of mad cow disease). Others described the first human studies of the popular dietary supplement CLA, and animal studies of polymer-enhanced aspirins.

Preserving plastics was another big theme. Smithsonian chemists explained how many techniques that curators now use to clean the works of old masters actually weaken the polymers in the paint, paving the way for further degeneration. And a researcher from the National Museum of Denmark warned against aging toys made from polyvinyl chloride (PVC). The findings show that old Barbies and the like can disrupt hormone development in children.

From soda bottles that hold more gas and plastic wraps that keep food fresher, to polymers that limit auto pollution and coatings that prevent metal rust, the findings go on. The following summaries offer some quick highlights.

More than half of Americans are considered overweight or obese. As a result, many of them are at risk for type 2, or adult onset, diabetes. In fact, a study published last week in the journal Diabetes Care noted that for every pound of excess weight, risk of developing diabetes increased by 4 percent. But according to several reports from the American Chemical Society (ACS), conjugated linoleic acid (CLA)--a popular nutritional supplement--offers a glimmer of hope: initial results indicate that this naturally occurring fatty acid (below) may aid in controlling weight and fat, retaining lean muscle mass, and battling diabetes.

In one study, conducted in Norway, of the 60 overweight subjects those who were given CLA but who were not allowed to diet lost "statistically significant" amounts of weight. According to Ola Gudmundsen, a principal investigator, average weight loss was equivalent to a 160-pound individual losing two to three pounds over a 12-week period. Though the team can't be certain that CLA enabled the weight loss, that is the implication of the study.

In a second study, conducted over six months at the University of Wisconsin, 80 overweight participants dieted and exercised, and, as a result, most lost weight. Yet once they stopped their regime, many put pounds back on. Those individuals taking CLA, however, regained the weight at a ratio of 50 percent fat to 50 percent muscle, as opposed to the 75 percent fat to 25 percent muscle ratio typical of those who did not take CLA. Such results suggest that CLA might be useful in weight management, said Michael Pariza, one of the study's lead researchers. He added that CLA made it easier for people to stick to their diets.

A third study tried to determine the efficacy of CLA against diabetes. In an eight-week clinical trial held at Purdue University, 64 percent of the subjects taking CLA experienced improved insulin levels. For the millions of Americans who suffer from type 2 diabetes, team member Martha Belury notes that combining CLA with pharmaceutical drugs could help to ease both the costs and the side effects of long-term drug use.

We all know that automobiles are a major culprit when it comes to pollution. To make matters worse, catalytic converters, which are used to reduce harmful auto emissions, may also be producing considerable quantities of ammonia (right). By analyzing emissions from the 60,000 vehicles that passed through a highway tunnel in California over a period of eight days, Robert Harley of the University of California at Berkeley and his colleagues determined that the typical car released roughly a teaspoon of ammonia for every 100 miles traveled. Harley explained that catalytic converters can over-reduce nitrogen oxide from the engine's exhaust, in which case ammonia gas forms and is released through the vehicle's tailpipe.

The good news is that researchers at General Technology Applications in Gainesville, Va., have developed a gasoline additive that they claim can increase horsepower and mileage, while decreasing harmful emissions. Currently used additives take the form of oxygenates, which supplement the amount of oxygen available for fuel combustion. Unlike these oxygenates, the new additive, known as polyisobutylene, is a polymer that alters the physical properties of gasoline so that it can burn more efficiently. Researchers are conducting field tests of polyisobutylene in the U.S. and abroad.

Since its invention in the 1890s, aspirin has become the most widely used drug in the world. Yet as effective as it is for relieving fever and inflammation, aspirin's active ingredient--salicylic acid(left)--is rough on the stomach lining, sometimes causing bleeding and stomach ulcers after prolonged use. Now a new form of aspirin made from polymers--the building blocks of plastics--could avoid such unwelcome side effects.

In this novel incarnation, aspirin molecules are arranged like a string of pearls to form a flexible chain, or polymer. Unlike regular aspirin, which breaks down and releases salicylic acid once it hits the corrosive environment of the stomach, the structure of the new drug (dubbed PolyAspirin) enables it to slip through the stomach acid intact, instead breaking down when it reaches the intestine, where it is absorbed and delivered to its target more efficiently.

As new uses for aspirin continue to emerge (prevention of heart attacks and strokes, for example), elimination of its drawbacks becomes even more desirable. And PolyAspirin may confer an additional advantage: mice given the drug experienced 37 percent more new bone growth than did a control group, which suggests that the drug might also be useful in treating gum disease or facilitating healing after a hip replacement, for example. Human clinical trials of PolyAspirin, expected to begin within two years, will no doubt be eagerly anticipated.

Though charming on antique garden furnishings, rust is a mortal enemy for most metal structures. But a plastic coating developed by the German company Ormecon Chemie GmbH promises to protect bridges, cars and other things at risk for rust, allowing them to last up to 10 times longer.

Conventional coatings such as paint or zinc can stave off rust by serving as physical barriers to the environment. Yet these are short-term solutions that wear off over time. The new coating, called polyaniline, intervenes in the oxidation process that leads to rust. Instead of the metal donating electrons to oxygen directly (and thus forming impurities that weaken the structure), the polyaniline accepts the electrons and subsequently gives them to oxygen. This reaction yields a layer of pure iron oxide that prevents corrosion. Field tests revealed polyaniline to be three to 10 times more effective than zinc in preventing rust. Furthermore, polyaniline, unlike zinc, is not a heavy metal, which can pose dangers to human health if not disposed of properly. The new coating is already being used in Asia and Europe.