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pigmentation

(Encyclopedia)pigmentation, name for the coloring matter found in certain plant and animal cells and for the color produced thereby. Pigmentation occurs in nearly all living organisms. Almost all plants synthesize ...

dialysis

(Encyclopedia)dialysis dīălˈĭsĭs [key], in chemistry, transfer of solute (dissolved solids) across a semipermeable membrane. Strictly speaking, dialysis refers only to the transfer of the solute; transfer of t...

nicotine

(Encyclopedia)nicotine, C10H14N2, poisonous, pale yellow, oily liquid alkaloid with a pungent odor and an acrid taste. It turns brown on exposure to air. Nicotine, a naturally occurring constituent of tobacco, is t...

heatstroke

(Encyclopedia)heatstroke, profound disturbance of the heat-regulating mechanism of the body, also known as sunstroke. It is characterized by extremely high body temperatures and sometimes by convulsions and coma. T...

Furchgott, Robert Francis

(Encyclopedia)Furchgott, Robert Francis, 1916–2009, American biochemist, b. Charleston, S.C., Ph.D. Northwestern Univ., 1940. Furchgott spent his entire career as a professor (1956–89) at the State Univ. of New...

macular degeneration

(Encyclopedia)macular degeneration, eye disorder causing loss of central vision. The affected area, the macula, lies at the back of the retina and is the part that produces the sharpest vision. The most serious vis...

parathyroid glands

(Encyclopedia)parathyroid glands pârˌəthīˈroid [key], four small endocrine bodies, located behind the thyroid gland, that govern calcium and phosphorus metabolism. These four masses of tissue (each about the s...

urine

(Encyclopedia)urine, clear, amber-colored fluid formed by the kidneys that carries metabolic wastes out of the body (see urinary system). As the blood circulates it collects excretory products from the tissues and ...

phlebitis

(Encyclopedia)phlebitis fləbīˈtĭs [key], inflammation of a vein. Phlebitis is almost always accompanied by a blood clot, or thrombus, in the affected vein, a condition known as thrombophlebitis (see thrombosis)...

aspirin

(Encyclopedia)aspirin, acetyl derivative of salicylic acid (see salicylate) that is used to lower fever, relieve pain, reduce inflammation, and thin the blood. Common conditions treated with aspirin include headach...