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heartburn

(Encyclopedia)heartburn, burning sensation beneath the breastbone, also called pyrosis. Heartburn does not indicate heart malfunction but results from nervous tension or overindulgence in food or drink. The sensati...

Grignard reagent

(Encyclopedia)Grignard reagent grēnyärdˈ rēāˈjənt [key], any of an important class of extremely reactive chemical compounds used in the synthesis of hydrocarbons, alcohols, carboxylic acids, and other compou...

methanol

(Encyclopedia)methanol, methyl alcohol, or wood alcohol, CH3OH, a colorless, flammable liquid that is miscible with water in all proportions. Methanol is a monohydric alcohol. It melts at −97.8℃ and boils at 6...

oxytocin

(Encyclopedia)oxytocin ŏksĭtōˈsĭn [key], hormone released from the posterior lobe of the pituitary gland that facilitates uterine contractions and the milk-ejection reflex. The structure of oxytocin, a cyclic ...

lipase

(Encyclopedia)lipase līˈpās [key], any enzyme capable of degrading lipid molecules. The bulk of dietary lipids are a class called triacylglycerols and are attacked by lipases to yield simple fatty acids and glyc...

keratin

(Encyclopedia)keratin kĕrˈətĭn [key], any one of a class of fibrous protein molecules that serve as structural units for various living tissues. The keratins are the major protein components of hair, wool, nail...

phospholipid

(Encyclopedia)phospholipid fŏsˌfōlĭpˈĭd [key], lipid that in its simplest form is composed of glycerol bonded to two fatty acids and a phosphate group. The resulting compound called phosphatidic acid contains...

borax

(Encyclopedia)borax or sodium tetraborate decahydrate sōˈdēəm tĕˌtrəbôrˈāt dĕkˌəhīˈdrāt [key], chemical compound, Na2B4O7·10H2O; sp. gr. 1.73; slightly soluble in cold water; very soluble in hot wa...

phenol

(Encyclopedia)phenol fēˈnōl [key], C6H5OH, a colorless, crystalline solid that melts at about 41℃, boils at 182℃, and is soluble in ethanol and ether and somewhat soluble in water. An aromatic alcohol, it ex...

hydrogen

(Encyclopedia)hydrogen hīˈdrəjən [key] [Gr.,=water forming], gaseous chemical element; symbol H; at. no. 1; interval in which at. wt. ranges 1.00784–1.00811; m.p. −259.14℃; b.p. −252.87℃; density 0.08...