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The first molecular keypad lock which works like by entering a series of numbers in a pre-set sequence has been designed by chemists at the Weizmann Institute. The main difference is that the Rehovot scientists created a molecule that can function like a super-miniaturized keypad locking mechanism. Their work recently appeared in the Journal of the American Chemical Society.
What possible uses are there for minuscule keypads? They aren't likely to become a practical alternative to today's anti-theft devices. But Shanzer believes this first-ever design will lead to new inventions in other areas such as information security and even medicine.
"Faster and more powerful molecular locks could serve as the smallest of ID tags, providing the ultimate defense against forgery," he suggests. In future, molecular keypads might prove valuable as well in designing "smart" diagnostic equipment to detect the release of biological molecules or changes that indicate disease.
The molecule, synthesized in the lab of organic chemistry Prof. Abraham Shanzer, is composed of two smaller linked units - fluorescent probes - separated by a molecular chain to which iron can bind. One of these probes can shine bright fluorescent blue and the other fluorescent green, but only if surrounding conditions are right. These conditions are the keypad inputs: Rather than the electric pulses of an electronic keypad, they consist of iron ions, acids, bases and ultraviolet light.
Shanzer and his group, which includes Drs. David Margulies, Galina Melman and Clifford Felder, have demonstrated that such molecules can be used as logic gates like those that form the basis of computer operations. As opposed to electronic logic gates, in which electrical switches flip ON and OFF, the team's molecules, with various combinations of chemical and light inputs, can switch between colors and light intensities to perform calculations.
The challenge in creating a keypad lock was in generating sequences that can be distinguished one from another. Entering the sequence 2+3+4 will yield the same result as 3+4+2 on a calculator, for example, but a keypad lock set to one password (234) won't open for the other (342). The scientists found that by controlling the opening rate of the logic gate within the reaction time frame, they were able to produce distinguishable outputs, depending on the input order. By adding light energy, which also influences the molecules' glow, they were able to produce a molecule-size device that lights up only when the correct chemical "passwords" are introduced. "It's just like a tiny ATM banking machine," says Shanzer.
FOR THE CRANES
The German airline Lufthansa, whose logo is a crane, obviously feels a lot of sympathy for these migrating birds. It has spent 120,000 euros - 10,000 this year alone - to keep an eye on them as they make a pit stop in Israel from Europe to Ethiopia in the fall and from Africa to Europe in the spring. The Ornithological Centers of the Society for the Protection of Nature Israel in Latrun, led by Dr. Yossi Leshem and Dan Alon, has reported 50,000 of the birds passing through the Hula Valley this season. Alon said that as a result of the research, friction between farmers and the hungry cranes has been cut. Instead of eating commercial crops, the cranes are fed nutritious but unneeded food in the Hula Valley. Thanks to Lufthansa's donations, satellites and transmitters have determined the birds' airborne itinerary from Israel to the north; soon, the path of their trip south to Ethiopia will be determined.
Knowing exactly how they make the trip is important, said the ornithologists, so they can know whether the cranes pass through places protected from hunting and poison. It's also vital to know where the birds are to reduce damage to Israeli fields by chasing them away and attracting them to feeding stations. Itai Shani, a representative of the Society for the Protection of Nature in Israel, returned recently from Ethiopia where he accompanied a delegation of scientists, including Germans, who counted the number of birds spending the winter in that African country.
Lufthansa-Israel's managing director Ofer Kisch said that as pioneers in the transmitter-satellite project, "we are proud again to help one of the important projects that have much importance to environmental quality in northern Israel. The airline, which donates to crane projects worldwide, has been operating in Israel since 1968 and runs 14 weekly flights between Ben-Gurion Airport and Frankfurt.
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