Carbon nanotubes (CNTs) have long held great promise as building blocks for next-generation materials and electronic devices. Lighter and stronger than steel, CNTs can also conduct electricity well. But efforts to combine them into usable structures haven't yielded much success to date. In the Aug. 19 issue of Science, however, scientists in Texas and Australia outline a new method to spin CNTs into thin sheets.
To make the sheets, trillions of individual CNTs -- chemically grown in forest-like clumps -- are teased together to create larger ropes, which in turn are merged into fabric strips. The resulting ultralight material -- an acre's worth would weigh as little as 4 oz. -- has potential uses in everything from space sails to light-emitting displays, and artificial muscles to transparent radio antennas, says Ray H. Baughman, the University of Texas at Dallas nanotechnologist who led the project. Prototype products using the fabric, he adds, could be available in 2006.
People with heart failure often suffer from the blues. Now scientists may have proof that it's not just the energy-sapping symptoms of their disease that makes heart patients feel down. On Aug. 19 researchers at the University of California at Los Angeles published a study linking heart disease to a form of brain damage that can cause depression.
MRI scans taken of patients with heart failure revealed tissue loss in the part of the brain that regulates the autonomic nervous system. That's the same region of the brain that exhibits changes in patients suffering from depression. The researchers, who published their findings in the Journal of Cardiac Failure, believe the brain damage also impedes blood-pressure regulation, making it uncomfortable for heart patients to exercise -- a key part of their recovery.
The findings may inspire drugmakers to search for heart-disease remedies able to cross the blood-brain barrier and prevent tissue injury. "Neuroprotection is the magic key," says Ronald M. Harper, professor of neurobiology at UCLA.
Humans have been exploiting the power of urine for centuries. The Romans brushed their teeth with it. Other cultures, such as the ancient Chinese, drank it to purify the body of all manner of ills. Now scientists in Singapore have devised a pee-powered battery to run tiny, portable test-kits for diseases such as diabetes.
The kits work thanks to a tiny chip made of copper, magnesium, and paper laced with copper chloride. A drop of urine on the credit-card-sized device starts a chemical reaction that causes a tiny electrical current -- enough to test the sample for diseases.
Dr. Ki Bang Lee, who led the research at Singapore's Institute of Bioengineering & Nanotechnology, is now working on chips powered by other bodily fluids. Lee figures cheap, disposable tests could help patients in underdeveloped countries to monitor their own minor health conditions. He also believes his invention could run a range of gizmos, including a saliva-powered emergency cell-phone. One lick may provide enough juice to make that vital call.
-- Environmentalists have long believed the most serious effects of global warming would be felt at high latitudes, where melting ice caps have already set off alarms. But now, University of Washington scientists believe the tropics may be in even more peril. In a study presented on Aug. 19, the researchers found that organisms in the steamy tropics have little tolerance for even tiny temperature shifts. That's because they haven't experienced normal seasonal swings allowing creatures in places such as Alaska to adapt to temperature changes. The research could shed light on which organisms are in danger of extinction.
-- A study released on Aug. 9 shows that some ecosystems cannot absorb as much carbon as scientists once believed they could. Jeffrey Dukes, a biologist at the University of Massachusetts, led a study exposing grasslands in California to excess CO2 and other global-warming conditions. The grasslands did not store much of the excess. Dukes hopes to study other ecosystems to better understand why some don't act as a buffer against global warming.