In "The Dog Nose Knows," Tufts University neuroscientists John Kauer and Joel White introduced Alan to a new machine (see photo) that they hope will one day save thousands of lives. These scientists have built a sniffing device modeled after a dog's nose that may help safely detect the estimated 50 to 100 million landmines buried around the world.

The device relies on a computer, a battery-pack and a hose-like "sniffer" that draws in odor molecules. When the inhaled molecules combine with chemical sensors inside the contraption, the sensors change colors, creating a signature visual pattern for each aroma. Light sensors "read" this pattern to determine the identity of the odor.

In the test run filmed by FRONTIERS in February of 2001, the artificial nose could easily differentiate between three odors: plain air, methanol, and DNT- a non-explosive chemical cousin to TNT. The machine was able to smell DNT at concentrations down to around 10 parts per billion. But in order to rival a real dog nose, Kauer and White told FRONTIERS that they hoped to bring this number down to as low as one part per billion. Four months later, they had some exciting results.

After improving and upgrading the machine's hardware and software, Kauer and White put their artificial nose up against some real dog noses at Auburn University in June of 2001. The device and the dogs were each exposed to decreasing concentrations of DNT. This time, their device performed just as well as the dogs did under similar test conditions. Both the dog noses and the man-made nose were able to detect the chemical at concentrations below one part per billion, the goal the scientists had aimed for. Kauer and White's device had improved tenfold.

The scientists also tested their artificial nose under more realistic conditions at the Defense Advanced Research Projects Agency's (DARPA) land mine test facility at Fort Leonard Wood in Missouri. Here, an enclosed field is planted with actual land mines, none of which have detonators, and all of which are clearly marked. Hovering over the markers, Kauer and White found their device could indeed detect the presence of some landmines under certain conditions.

It's promising data, but White cautions that the work is still in its early stages. "We're still a long way away from being willing to walk across an unmarked field blindly," says White from his lab at Tufts. "But it's definitely a step in that direction."

photo: © Michael Lutch
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