free radicals


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free radicals

Highly chemically active atoms or group of atoms capable of free existence, under special conditions, for very short periods, each having at least one unpaired electron in the outer shell. Oxygen free radicals can be very damaging to DNA and proteins and to the fat in cell membranes where a free radical chain reaction can be set up. They are normally mopped up by ANTIOXIDANTS and associated substances such as vitamins E and C, FLAVONOIDS, selenium, copper, zinc, and manganese. Produced in excess, or insufficiently opposed, free radicals are believed to be implicated in the production of ATHEROSCLEROSIS, cancer, RHEUMATOID ARTHRITIS, radiation sickness and many other conditions. They are thought to be responsible for much of the damage to the heart during the reperfusion that follows a coronary thrombosis. They are said to be promoted by many agents including radiation, atmospheric pollutants and smoking. The body's natural antioxidants include superoxide dismutase and vitamins C and E. See also NANOPARTICLES.

free radicals,

n.pl compounds with an unpaired electron, which makes them extremely reactive.
References in periodicals archive ?
Basically, free radicals are oxygen molecules that contain one or more unpaired electrons in their orbits.
As shown, the first step in the vulcanization process is the decomposition of the peroxide into free radicals.
Scientists are working on perfecting a process called Electron Paramagnetic Resonance (EPR) that can measure levels of free radicals in substances like teeth.
In such a manner they create new free radicals that, in turn, damage the body.
The researchers examined the nano-particles with magnetic fields tuned to identify unpaired electrons, the feature that makes free radicals highly reactive and potentially dangerous to living cells.
Lai and Singh's findings support the so-called free radical hypothesis, which posits that extremely-low-frequency EMFs increase free radical activity in cells, thereby causing DNA damage and disturbing other cellular processes and functions.
Researchers measured evidence of lipid peroxidation--looking for evidence that free radicals had oxidized blood lipids, a process thought to contribute to atherosclerosis.
The damaging effects of free radicals are not a recent discovery.
Over the last two decades the application of free radicals in organic synthesis, materials science and life science has steadily increased, this Encyclopedia presents methodologies and mechanisms involving free radicals of chemical and biological research, including applications in materials science and medicine.
Free radicals are produced by the body and have a tendency to damage DNA, making some people take supplements to mop them up.
Antioxidants neutralize the free radicals that occur naturally on the skin.