Washington, Oct 14 : Researchers have devised an advanced programme for biomolecular computers that enables them to 'think' logically.

Research students Tom Ran and Shai Kaplan, students of Ehud Shapiro at Weizmann Institute's biological chemistry lab have found a way to make these devices 'user friendly,' even while performing complex computations and answering complicated queries.

The team introduced the first autonomous programmable DNA computing device in 2001.

A new version, created in 2004, detected cancer in a test tube and released a molecule to destroy it. Besides the possibility that such biology-based devices could one day be injected into the body - a sort of ?doctor in a cell' locating disease and preventing its spread, biomolecular computers could conceivably perform millions of calculations in parallel.

The train of deduction used by this futuristic device is remarkably familiar. It was first proposed by Aristotle over 2,000 years ago as a simple if... then proposition: 'All men are mortal. Socrates is a man. Therefore, Socrates is mortal.'

When fed a rule (All men are mortal) and a fact (Socrates is a man), the computer answered the question 'Is Socrates Mortal?' correctly.

The team went on to set up more complicated queries involving multiple rules and facts, and the DNA computing devices were able to deduce the correct answers every time.

These findings were published online in Nature Nanotechnology. (IANS)