SCIENCE: LAB NOTES

A BLOODLESS COUP

New instruments for measuring blood sugar without drawing blood could soon become available to people with diabetes. Experts believe they could both help the many millions of diabetics around the world and also reduce the multi- billion pound bill disease brings through direct medical costs, disability and lost earnings. The greatest obstacle to the rise of these devices could be economic, however. It remains uncertain whether insurance companies will cover the cost of the devices, and they may not be routinely affordable otherwise. Currently, many diabetics must prick their fingers with a lancet one or more times a day to check their blood glucose levels. Drops of blood can be placed on paper test strips, for example, and analysed by a small meter. These instruments are not expensive by themselves, but the cost of test strips can reach more than pounds 90 per month.

A bigger problem is that finger-pricking can be inconvenient and painful. Many diabetics therefore do not monitor themselves as closely as they should, and put themselves at a higher risk for kidney failure, stroke or blindness. The non-invasive systems are painless, which could improve compliance.

The Diasensor 1000, manufactured by Biocontrol Technology of Pittsburgh, Pennsylvania, uses infrared light to read blood sugar levels without breaking the skin. The light, emitted by a fibre-optic probe, passes through the skin and blood, then reflects back for analysis by the Diasensor. The amount of light absorption indicates the amount of glucose in the blood. The Diasensor 1000 recently received market approval from the European Union.

Cygnus of Redwood City, California, is currently finishing clinical trials for its GlucoWatch. Worn like an ordinary wristwatch, the monitor uses low-level electric current to extract samples of glucose painlessly from the skin and move it onto a transdermal pad for measurement.

While Pacific Biometrics in Lake Forest, California, is currently developing the SalivaSac, which would help to filter contaminants out of saliva so that it could be used for glucose monitoring.

Unfortunately, insurance companies are generally reluctant to pay for glucose monitoring, and the short-term costs of the new systems are relatively high. Biocontrol intends to sell its Diasensor 1000 for more than pounds 5,000. The GlucoWatch will probably cost under pounds 150 but it relies on pounds 2.50 transdermal pads that must be changed twice daily.

BREWING POWER

Next year, Japanese brewers will install new fuel cells in their operations to turn waste gas from the brewing process into energy. Fuel cells provide electricity by drawing electrons out of reactions in which hydrogen and oxygen gas combine, forming water. They are attractive as a low-pollution power source, but have not yet achieved widespread industrial use because of the costs of obtaining hydrogen gas.

Breweries, however, have a ready source of hydrogen - in the form of methane, which is produced as a byproduct from the process of fermentation. According to Nikkei America, fuel cells that are made by Mitsubishi Electric Corporation are providing power to Asahi and Sapporo breweries in Japan, and the Kirin Brewery Company's Tochigi brewery will be installing a fuel cell next year.

PESSIMISTS HAVE MORE FUN

Looking on the bright side of life may not be the best way to hold off depression - at least among the elderly. In fact, according to a recent study conducted at the University of Pennsylvania, older pessimists seem to have decidedly better moods than their optimistic peers.

Researchers Derek Isaacowitz and Martin Seligman followed 71 adults, aged 64 to 94, for one year to see how they responded to life's disappointments. The psychologists expected to find that generally pessimistic individuals would be more prone to depression, as is true in younger people. Instead, they found the reverse: elderly pessimists appeared to experience less depression after adverse developments. What could explain these paradoxical results? Being optimistic may not always be a realistic strategy for coping late in life, the researchers suggest.

CLOCKWATCHERS OF

THE FUTURE UNITE

A group led by Carl Wieman of the University of Colorado at Boulder has tested what could become the basis for the world's most accurate clock. At this moment in time, the most accurate way to keep time is with an atomic, or "cesium" clock - a device in which millions of cesium atoms flip between two configurations, ticking off fractions of a second. One limit to the precision of a cesium clock is that these masses of atoms interact and slightly trip up one another's regular beats.

Wieman's group has solved this problem by creating a form of "superatom", called a Bose-Einstein condensate. This condensate consists of many atoms, all cooled to close to absolute zero. Because of quantum physics, all the atoms then become essentially identical, at which point they mark the billionths of a second in perfect unison.

WHEN WAR MOVES TO TOWN

American military planners, assessing the types of terrain where they may be asked to wage war in the coming century, have concluded that the likeliest settings for conflict may be cities. These military operations in urban terrain, or MOUTS, will require a new approach to fight-ing. Tacticians are scrambling to ensure that American forces will be ready. During the past decades, US military planners devoted much of their thinking, energies and budget to preparations for nuclear conflicts, most likely with the Soviet Union. More limited engagements, involving infantries and the occupation of disputed land, were mapped after the battles of the World Wars and the conflicts in both Korea and Vietnam. But recent experiences in Bosnia and elsewhere have convinced the Pentagon that in the post-Cold War era, US forces may more often be called upon to fight guerrilla- style battles in cities. "Our military doctrine has been one of avoiding cities," explains Carol Fitzgerald, the director of an Army programme for testing new fighting concepts. "We can't avoid them any longer."

Fitzgerald's programme and others are developing tools and weapons systems better suited to dealing with an enemy that could be lurking inside a seemingly empty building or beneath a manhole cover. New sensors and observation equipment includes night-vision goggles and remote-controlled cameras mounted on robots and small aircraft. Digital map systems, related to the satellite global positioning systems and similar navigational equipment now found in some cars, can help soldiers determine their own relative positions and those of other forces. Hands-free communication systems will help soldiers stay in touch with base without dropping their guard.

Weapons and vehicles are also being overhauled. Small shaped-explosive charges are being tested for the ability to punch door-sized holes through walls without knocking them down completely. Highly manoeuvrable parafoils, or guided parachutes, could help infantrymen move quickly between the tops of buildings.

Even surprisingly low-tech equipment can be of help. According to Fitzgerald, soldiers in city combat exercises have benefited mightily from simply using elbow and knee pads like those used by in-line skaters.

! All items, except as noted, are adapted from 'Scientific American' magazine. Visit the 'Scientific American' website at www.sciam.com. Copyright 1998, Scientific American, Inc. All rights reserved