As part of the treatment, doctors inject the light-activated dye into the patient's arm.

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The nastiest-looking arteries might be stabilized with some form of local therapy, such as drug-coated stents, light-activated drugs to kill off inflamed cells or even gene therapy.

FORBES: Peeking at Plaque

The first light-activated neurons were cultivated as layers of cells in Petri dishes, but researchers were quickly able to make the technique work in flies, worms, zebrafish, mice, and monkeys.

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For instance, says Harp, the Boston Eye and Ear Infirmary is involved in patent litigation with QLT Incorporated (nyse: QLTI - news - people ), a Vancouver-based firm specializing in light-activated drugs.

FORBES: Magazine Article

The Port Authority of New York and New Jersey, which owns the site, said the LED-powered light would be activated in the next few months.

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Researchers at Stanford University and MIT's Picower Institute for Learning and Memory had activated light-sensitive neurons in the brain's hippocampus involved in the memory of fright.

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This, Dr Silver is convinced, is because the activity in the light-sensitive neurons somehow activated a latent nerve pathway that spans both sides of the spinal cord, allowing them to synchronise.

ECONOMIST: Neurology

Pharmacyclics's drug, called lutetium-texaphyrin, is activated by red light.

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More than 10 years ago, researchers at Massachusetts General Hospital in Boston and other centers discovered the compound aminolevulinic acid, or ALA, is a photosensitizer, meaning it is activated by certain wavelengths of light.

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Methods are already being developed to implant a light source inside the body which could be activated by remote control.

ECONOMIST: Neurology