ChemWeb Newsletter

Not a subscriber? Join now.October 29, 2004


There is no excuse not to include the latest research on pumpkins in this issue, so we report how members of that plant species can soak up DDT from soil and might lead to an inexpensive approach to bioremediation in the developing world. Next story up is the discovery that liquids that can guide light through a chip, the finding might lead to an entirely new class of chemical and biological sensor. We also discover how spectroscopy can under-study for crystallography and reveal that compounds found in strong-flavored onions, as opposed to tasteless ones, might be useful in the fight against cancer. Finally, a "data cave," in the style of the Minority Report crime investigation room could one day speed up the discovery of useful chemicals.

Members of the Cucurbita pepo species of plants, which includes the Halloween favorite, the pumpkin, and the zucchini, can quickly remove the pesticide DDT from soil, according to greenhouse tests carried out by chemists at the Royal Military College of Canada. Persistent organic pollutants, such as DDT, polychlorobiphenyls and dioxins, are insoluble in water so are difficult to remove from soil. A problem that only gets worse with the passage of time. To clean up contaminated sites, it is usually necessary to excavate the soil and place it in a landfill or burn it in a high-temperature incinerator. "Phytoremediation offers a 'green' solution to cleaning up contaminated sites," says Ken Reimer whose team has found that pumpkins can take up large amounts of DDT directly from the soil. One problem remains - how to prevent wildlife and people from eating the remedial crops. Reamer and his team are now searching for inedible species that might do the job just as well.

Light can be guided through tiny channels with liquid cores, according to researchers at the University of California, Santa Cruz. They report that their first demonstration of an integrated optical waveguide with a liquid core allows light propagation through small volumes of liquids on a chip. UCSC's Holger Schmidt explains that this enabling technology opens up many new possibilities for integrating optics into semiconductor devices for sensors and other applications. Schmidt is working toward chemical sensing of single molecules using liquid-core waveguides. He also sees potential applications for gas-core waveguides in the areas of atomic physics and quantum optics.

French researchers have suggested that crystallographic information can be obtained without resorting to crystallography. Francis Taulelle of the Louis Pasteur University has demonstrated that a back to basics approach to crystallography reveals that a crystallochemical formula can fit a particular space group and so provide a basic crystal structure on the basis of NMR studies combined with other chemical and spectroscopic information. Given the chemical formula and the spectroscopic information available, the crystal space group of even non-crystallizable can be obtained.

Cornell University researchers have found that members of the onion family with the strongest flavor, in particular New York Bold, Western Yellow and shallots, contain potent inhibitors of liver and colon cancer cell growth, in preliminary laboratory studies, at least. Rui Hai Liu and colleagues analyzed ten common onion varieties and shallots for total antioxidant activity and their ability to fight the growth of cancer in human cell lines. They used fresh, uncooked samples with extracts taken from the bulbs with the outer skin removed. Their results showed that a strong flavor correlated directly with potent antioxidant activity. The team reports its results in the November 3 issue of the ACS's Journal of Agricultural & Food Chemistry.

A virtual reality environment reminiscent of the crime-fighting room in the Steven Spielberg movie, Minority Report could be used to help chemists uncover the necessary knowledge to design new catalysts, pharmaceuticals, polymers, and other products. "You could walk right up to this display and move molecules and atoms around to see how the changes would affect a formulation or a material's properties," explains chemical engineer James Caruthers of Purdue University. The method, called "discovery informatics, "enables researchers to test new theories on the fly and literally see how well new concepts might work in real time using a three-dimensional display.