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- LONDON (Reuters) - U.S. defence scientists have developed small radio-controlled
planes capable of ``sniffing out'' the presence of biological weapons,
a British magazine reported on Wednesday. New Scientist said the aircraft,
described by one of their developers as ``like little toy planes,'' are
designed to fly low into danger zones looking for up to four suspected
types of bacteria. As they patrol, air is forced into an on-board sampling
chamber, creating a vortex in a pool of water, the magazine said. Every
five minutes, water from this chamber is pumped over a sensor consisting
of four optical fibres, each of which has a probe fixed to its core. Each
probe is coated with an antibody to which the spores of a particular bacterium
will bind if present in the water. The planes send out electronic signals,
generated by a second set of fluorescent antibodies, if they find even
minute quantities of the suspected bacteria. ``They're remote controlled,
like little toy planes. They're cheap and they fly low, which is where
you need to be,'' New Scientist quoted Frances Ligler of Washington's Naval
Research Laboratory as saying. It said Ligler and her team had tested a
plane, with a four metre (yard) wingspan and weighing 19 kg (42 lbs), using
a harmless bacterium which they had sprayed into the air. Depending on
the temperature, it took between five and 20 minutes for the plane to detect
the bacterium.
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