| reabsorption | 1. The act or process of absorbing again, as the selective absorption by the kidneys of substances (glucose, proteins, sodium, etc.) already secreted into the renal tubules and their return to the circulating blood. 2. Resorption. (18 Nov 1997) |
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| reach | 1. To extend; to stretch; to thrust out; to put forth, as a limb, a member, something held, or the like. "Her tresses yellow, and long straughten, Unto her heeles down they raughten." (Rom. Of R) "Reach hither thy hand and thrust it into my side." (John xx. 27) "Fruit trees, over woody, reached too far Their pampered boughs." (Milton) 2. Hence, to deliver by stretching out a member, especially the hand; to give with the hand; to pass to another; to hand over; as, to reach one a book. "He reached me a full cap." (2 Esd. Xiv. 39) 3. To attain or obtain by stretching forth the hand; too extend some part of the body, or something held by one, so as to touch, strike, grasp, or the like; as, to reach an object with the hand, or with a spear. "O patron power, . . . Thy present aid afford, Than I may reach the beast." (Dryden) 4. To strike, hit, or tough with a missile; as, to reach an object with an arrow, a bullet, or a shell. 5. Hence, to extend an action, effort, or influence to; to penetrate to; to pierce, or cut, as far as. "If these examples of grown men reach not the case of children, let them examine." (Locke) 6. To extend to; to stretch out as far as; to touch by virtue of extent; as, his hand reaches the river. "Thy desire . . . Leads to no excess That reaches blame." (Milton) 7. To arrive at by effort of any kind; to attain to; to gain; to be advanced to. "The best account of the appearances of nature which human penetration can reach, comes short of its reality." (Cheyne) 9. To understand; to comprehend. "Do what, sir? I reach you not." (Beau. & Fl) 10. To overreach; to deceive. Origin: Reached (Raught, the old preterit, is obsolete); Reaching] [OE. Rechen, AS. Raecan, raecean, to extend, stretch out; akin to D. Reiken, G. Reichen, and possibly to AS. Rice powerful, rich, E. Rich. 1. The act of stretching or extending; extension; power of reaching or touching with the person, or a limb, or something held or thrown; as, the fruit is beyond my reach; to be within reach of cannon shot. 2. The power of stretching out or extending action, influence, or the like; power of attainment or management; extent of force or capacity. "Drawn by others who had deeper reaches than themselves to matters which they least intended." (Hayward) "Be sure yourself and your own reach to know." (Pope) 3. Extent; stretch; expanse; hence, application; influence; result; scope. "And on the left hand, hell, With long reach, interposed." (Milton) "I am to pray you not to strain my speech To grosser issues, nor to larger reach Than to suspicion." (Shak) 4. An extended portion of land or water; a stretch; a straight portion of a stream or river, as from one turn to another; a level stretch, as between locks in a canal; an arm of the sea extending up into the land. "The river's wooded reach." "The coast . . . Is very full of creeks and reaches." (Holland) 5. An article to obtain an advantage. "The Duke of Parma had particular reaches and ends of his own underhand to cross the design." (Bacon) 6. The pole or rod which connects the hind axle with the forward bolster of a wagon. Source: Websters Dictionary (01 Mar 1998) |
| react | 1. To return an impulse or impression; to resist the action of another body by an opposite force; as, every body reacts on the body that impels it from its natural state. 2. To act upon each other; to exercise a reciprocal or a reverse effect, as two or more chemical agents; to act in opposition. Source: Websters Dictionary (01 Mar 1998) |
| reactance | The weakening of an alternating electric current by passage through a coil of wire or a condenser. Synonym: inductive resistance. (05 Mar 2000) |
| reactant | A substance taking part in a chemical reaction. Acute phase reactants, A group of proteins that are produced and/or released in increased concentrations during the acute phase reaction, including fibrinogen; C-reactive protein; complement proteins B, C3, C4; a2-acid glycoprotein, serum amyloid A, proteinase inhibitors, etc. (05 Mar 2000) |
| reaction | Standard method for identifying Clostridium perfringens. When grown on agar containg egg yolk, an opalescent halo is formed around colonies that produce _ toxin (lecithinase). (18 Nov 1997) |
| reaction centre | <plant biology> The site in the chloroplast that receives the energy trapped by chlorophyll and accessory pigments and initiates the electron transfer process. A photosynthetic complex containing chlorophyll (or bacteriochlorophyll) and other components, within which occurs the initial electron transfer reactions of photophosphorylation. (09 Oct 1997) |
| reaction formation | In psychoanalysis, a postulated defense mechanism in which attitudes and behaviours that are adopted are the opposites of that which the individual would ordinarily be expected to express and actually feel at an unconscious level. (05 Mar 2000) |
| reaction intermediate | <biochemistry> Any biomolecule which iscreated and destroyed during the course of of a particular reaction pathway. (09 Oct 1997) |
| reaction of degeneration | The electrical reaction in a degenerated nerve and the muscles supplied by it; characterised by absence of response to both galvanic and faradic stimulus in the nerve and to faradic stimulus in the muscles; the muscles may still respond to galvanic stimulation, but the cathodal closing contraction is greater than the anodal closing contraction, the reverse of normal. (05 Mar 2000) |
| reaction of identity | See: gel diffusion precipitin tests in two dimensions. (05 Mar 2000) |
| reaction of nonidentity | See: gel diffusion precipitin tests in two dimensions. (05 Mar 2000) |
| reaction of partial identity | See: gel diffusion precipitin tests in two dimensions. (05 Mar 2000) |
| reaction quotient | <chemistry> A constant represented by the symbol Q which is defined as the product of the concentrations of the products, each raised to the power that corresponds to its coefficient in the balanced equation, divided by the product of the concentrations of reactants, each raised to the power that corresponds to its coefficient in the balanced equation (see the equation in the equations page). at equilibrium conditions Q=K, the equilibrium constant. (09 Jan 1998) |
| reaction time | The time from the onset of a stimulus until the organism responds. (12 Dec 1998) |