| BB | bad breath; bed bath; beta blockade, beta blocker; BioBreeding [rat]; blanket bath; blood bank; bloo... |
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| B-K | initials of two patients after whom a multiple cutaneous nevus [mole] was named |
| D2 | diagonal two; second dorsal vertebra |
| 2-D | two-dimensional |
| 2DE | two-dimensional echocardiography |
| two-stream amplifier | <radiobiology> Microwave amplifier based on the two-stream instability. (09 Oct 1997) |
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| two-stream instability | <radiobiology> Instability which can develop when a stream of particles of one type has a velocity distribution with its peak well separated from that of another type of particle through which it is flowing. A stream of energetic electrons passing through a cold plasma can, for example: excite ion waves which will grow rapidly in magnitude at the expense of the kinetic energy of the electrons. (09 Oct 1997) |
| two-sympathin theory | A theory, now obsolete, advanced by Cannon and Rosenblueth that two different types of substances (sympathin E and I) diffuse into circulation when adrenergic nerves are stimulated, although the mediator itself is the same. (05 Mar 2000) |
| two-tail test | A statistical test based on the assumption that the data are distributed in both directions from some central value. (05 Mar 2000) |
| two-way catheter | A catheter with two lumens, allowing irrigation and aspiration. Synonym: two-way catheter. (05 Mar 2000) |
| glass | 1. A hard, brittle, translucent, and commonly transparent substance, white or coloured, having a conchoidal fracture, and made by fusing together sand or silica with lime, potash, soda, or lead oxide. It is used for window panes and mirrors, for articles of table and culinary use, for lenses, and various articles of ornament. Glass is variously coloured by the metallic oxides; thus, manganese colours it violet; copper (cuprous), red, or (cupric) green; cobalt, blue; uranium, yellowish green or canary yellow; iron, green or brown; gold, purple or red; tin, opaque white; chromium, emerald green; antimony, yellow. 2. <chemistry> Any substance having a peculiar glassy appearance, and a conchoidal fracture, and usually produced by fusion. 3. Anything made of glass. Especially: A looking-glass; a mirror. A vessel filled with running sand for measuring time; an hourglass; and hence, the time in which such a vessel is exhausted of its sand. "She would not live The running of one glass." (Shak) A drinking vessel; a tumbler; a goblet; hence, the contents of such a vessel; especially; spirituous liquors; as, he took a glass at dinner. An optical glass; a lens; a spyglass; in the plural, spectacles; as, a pair of glasses; he wears glasses. A weatherglass; a barometer. Glass is much used adjectively or in combination; as, glass maker, or glassmaker; glass making or glassmaking; glass blower or glassblower, etc. Bohemian glass, Cut glass, etc. See Bohemian, Cut, etc. Crown glass, a variety of glass, used for making the finest plate or window glass, and consisting essentially of silicate of soda or potash and lime, with no admixture of lead; the convex half of an achromatic lens is composed of crown glass; so called from a crownlike shape given it in the process of blowing. Crystal glass, or Flint glass. See Flint glass, in the Vocabulary. Cylinder glass, sheet glass made by blowing the glass in the form of a cylinder which is then split longitudinally, opened out, and flattened. Glass of antimony, a vitreous oxide of antimony mixed with sulphide. Glass blower, one whose occupation is to blow and fashion glass. Glass blowing, the art of shaping glass, when reduced by heat to a viscid state, by inflating it through a tube. Glass cloth, a woven fabric formed of glass fibres. Glass coach, a coach superior to a hackney-coach, hired for the day, or any short period, as a private carriage; so called because originally private carriages alone had glass windows. "Glass coaches are [allowed in English parks from which ordinary hacks are excluded], meaning by this term, which is never used in America, hired carriages that do not go on stands. (J. F. Cooper) Glass cutter. One who cuts sheets of glass into sizes for window panes, ets. One who shapes the surface of glass by grinding and polishing. A tool, usually with a diamond at the point, for cutting glass. Glass cutting. The act or process of dividing glass, as sheets of glass into panes with a diamond. The act or process of shaping the surface of glass by appylying it to revolving wheels, upon which sand, emery, and, afterwards, polishing powder, are applied; especially of glass which is shaped into facets, tooth ornaments, and the like. Glass having ornamental scrolls, etc, cut upon it, is said to be engraved. Glass metal, the fused material for making glass. Glass painting, the art or process of producing decorative effects in glass by painting it with enamel colours and combining the pieces together with slender sash bars of lead or other metal. In common parlance, glass painting and glass staining (see Glass staining, below) are used indifferently for all coloured decorative work in windows, and the like. Glass paper, paper faced with pulvirezed glass, and used for abrasive purposes. Glass silk, fine threads of glass, wound, when in fusion, on rapidly rotating heated cylinders. Glass silvering, the process of transforming plate glass into mirrors by coating it with a reflecting surface, a deposit of silver, or a mercury amalgam. Glass soap, or Glassmaker's soap, the black oxide of manganese or other substances used by glass makers to take away colour from the materials for glass. Glass staining, the art or practice of colouring glass in its whole substance, or, in the case of certain colours, in a superficial film only; also, decorative work in glass. Cf. Glass painting. Glass tears. See Rupert's drop. Glass works, an establishment where glass is made. Heavy glass, a heavy optical glass, consisting essentially of a borosilicate of potash. Millefiore glass. See Millefiore. Plate glass, a fine kind of glass, cast in thick plates, and flattened by heavy rollers, used for mirrors and the best windows. Pressed glass, glass articles formed in molds by pressure when hot. <chemistry> Soluble glass See Soluble glass, above. Window glass, glass in panes suitable for windows. Origin: OE. Glas, gles, AS. Glaes; akin to D, G, Dan, & Sw. Glas, Icel. Glas, gler, Dan. Glar; cf. AS. Glaer amber, L. Glaesum. Cf. Glare, Glaze. Source: Websters Dictionary (01 Mar 1998) |
| glass bead steriliser | A steriliser for endodontic equipment; the heat is transmitted to the instruments, absorbent points, or cotton pellets by means of glass beads. (05 Mar 2000) |
| glass body | A circular body of extreme transparency except for a crescentic punctate substance on one edge which contains haemoglobin. The body is much larger than a red blood cell, but is thought possibly to be a degenerated red blood cell swollen by imbibition; it has been found in malaria and in convalescence from typhoid fever; the transparent portion is called the glass body. (05 Mar 2000) |
| glass-crab | <zoology> The larval state (Phyllosoma) of the genus Palinurus and allied genera. It is remarkable for its strange outlines, thinness, and transparency. See Phyllosoma. Source: Websters Dictionary (01 Mar 1998) |
| glass electrode | A thin-walled glass bulb containing a standard buffer solution, quinhydrone, and a platinum wire; when immersed in an unknown solution, a potential difference develops that varies with the pH of the unknown solution; this difference can be made to give the pH; used in pH meters. (05 Mar 2000) |
| glass factor | <chemical> Stable blood coagulation factor activated by contact with the subendothelial surface of an injured vessel. Along with prekallikrein, it serves as the contact factor that initiates the intrinsic pathway of blood coagulation. Kallikrein activates factor xii to xiia. Deficiency of factor xii, also called the hageman trait, leads to increased incidence of thromboembolic disease. Chemical name: Blood-coagulation factor XII (12 Dec 1998) |
| glass ionomer cement | A dental cement produced by mixing a powder prepared from a calcium aluminosilicate glass with an aqueous solution of polyacrylic acid. Origin: ion + -mer (05 Mar 2000) |
| glass ionomer cements | A polymer obtained by reacting polyacrylic acid with a special anion-leachable glass (alumino-silicate). The resulting cement is more durable and tougher than others in that the materials comprising the polymer backbone do not leach out. (12 Dec 1998) |
| glass rays | Those formed by cathode ray's striking the wall of an X-ray tube. (05 Mar 2000) |
| glass-rope | <zoology> A remarkable vitreous sponge, of the genus Hyalonema, first brought from Japan. It has a long stem, consisting of a bundle of long and large, glassy, siliceous fibres, twisted together. Source: Websters Dictionary (01 Mar 1998) |