Injected into the body, these minuscule dots are just the right size to pass through the leaky blood vessels found around cancer cells and lodge near them. The researchers have also boosted the dots' tumor-finding ability by attaching antibodies that seek out cancer cells.
In mice, the researchers showed that the technique can spot tiny clumps of cancer missed by existing methods. Toxicity issues must be worked out, but in theory, quantum dots could provide earlier detection of cancer, says Nie. And scientists are already thinking about adding drugs to the quantum dots to create "smart bombs" that can be tracked as they target cancer cells. Coral reefs are the most diverse marine habitats known. And 25% of these ocean oases are "damaged beyond repair," says Joan A. Kleypas of the U.S. National Center for Atmospheric Research. Kleypas and her colleagues have published a report for the Pew Center on Global Climate Change detailing the threats to reefs.
The scientists found that some landborne pathogens have been able to adapt to life in the sea, killing coral and/or the symbiotic microalgae that live inside them. Meanwhile, silt, pesticides, and other pollutants are washing into the oceans, harming reefs. The final insult: Rising global temperatures cause the coral creatures to cough out their algal partners. The researchers strongly urged nations to curb fishing, reduce pollution, and take steps to slow global warming. Environmental protection and economic development are usually seen as being at loggerheads. Putting restrictions on, say, a pristine wilderness lake is often assumed to reduce property values, since the lakeshore can't be as fully developed. But it doesn't have to be that way, according to a study by environmental economist R. William Provencher at the University of Wisconsin at Madison.
He looked at what happened in Vilas County, Wis., after residents became concerned about the environmental health of their lakes. In 1999, the county passed an ordinance limiting development near certain ecologically sensitive North Woods lakes. Using data on property sales, Provencher found that the value of shoreline property increased substantially following the restrictions -- by as much as 24% at one lake.
The results, Provencher suggests, show that environmental preservation bestows considerable market value -- enough to entice people to give up development rights in exchange for a more pristine, and desirable, environment. -- Doctors are getting a clearer picture of how alcohol can damage the brains of unborn babies. Dr. John W. Olney of Washington University School of Medicine in St. Louis has shown that even brief exposures to alcohol and some drugs can trigger nerve-cell death in infant mice. Alcohol appears to block the formation of connections between cells -- and cells that fail to make connections are genetically programmed to die. Because different parts of the brain form links at different times, exposure to alcohol can produce a range of defects, from learning difficulties to poor motor skills.
-- Some species of microbes that live in oxygen-free environments are proving to be wizards at cleaning up uranium-contaminated groundwater and other pollution. And by attaching the bugs to electrodes, scientists have been able to create biological fuel cells powered by organic waste.