| ARM | adrenergic receptor material; aerosol rebreathing method; ambulatory renal monitor; anorectal manome... |
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| AROM | active range of motion; artificial rupture of membranes |
| PPROM | preterm premature rupture of fetal membranes |
| PRFM | premature rupture of fetal membranes |
| PRM | phosphoribomutase; photoreceptor membrane; premature rupture of membranes; Primary Reference Materia... |
acute angle
| anion exchange | The process by which an anion in a mobile (liquid) phase exchanges with another anion previously bound to a solid, positively charged phase, the latter being an anion exchanger. It takes place when Cl- is exchanged for OH- in desalting. The reaction is Cl- (in solution) + (OH- on anion exchanger+) → (Cl- on anion exchanger) + OH- (in solution); combined with cation exchange, NaCl is removed from solution. Anion exchange may also be used chromatographically, to separate anions, and medicinally, to remove an anion (e.g., Cl-) from gastric contents or bile acids in the intestine. (05 Mar 2000) |
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| anion exchange resin | <chemistry> A resin with fixed cationic groups which is used in chromatography to separate anionic molecules. A High molecular weight, insoluble polymers that contain functional anionic groups capable of undergoing exchange reactions. These resins are used for ion exchange chromatography, as gastric antacids, hypocholesteraemics, etc. (14 Aug 2000) |
| maternal-foetal exchange | Exchange of substances between the maternal blood and the foetal blood through the placental barrier. It excludes microbial or viral transmission. (12 Dec 1998) |
| cation exchange | The process by which a cation in a liquid phase exchanges with another cation present as the counter-ion of a negatively charged solid polymer (cation exchanger). A cation-exchange reaction in removal of the Na+ of a sodium chloride solution is RSO3-H+ + Na+ → RSO3-Na+ + H+ (R is the polymer, RSO3- is the cation exchanger); if this is combined with the anion-exchange reaction, NaCl is removed from the solution (desalting). Cation exchange may also be used chromatographically, to separate cations, and medicinally, to remove a cation; e.g., H+, from gastric contents, or Na+ and K+ in the intestine. See: anion exchange. (05 Mar 2000) |
| cation-exchange resin | See: cation exchange, cation exchanger. (05 Mar 2000) |
| cation exchange resins | High molecular weight insoluble polymers which contain functional cationic groups that are capable of undergoing exchange reactions; used in various types of chromatography; also to treat hyperkalaemia. (12 Dec 1998) |
| respiratory exchange ratio | The ratio of the net output of carbon dioxide to the simultaneous net uptake of oxygen at a given site, both expressed as moles or STPD volumes per unit time; in the steady state, respiratory exchange ratio is equal to the respiratory quotient of metabolic processes. (05 Mar 2000) |
| charge exchange | <radiobiology> Phenomenon in which an ion colliding with a molecule (or an atom) neutralises itself by capturing an electron from the molecule or atom, and transforming the molecule or atom into a positive radical or ion. (13 Nov 1997) |
| plasma exchange | Removal of plasma and replacement with various fluids, e.g., fresh frozen plasma, plasma protein fractions (ppf), albumin preparations, dextran solutions, saline. Used in treatment of autoimmune diseases, immune complex diseases, diseases of excess plasma factors, and other conditions. (12 Dec 1998) |
| pulmonary gas exchange | The exchange of oxygen and carbon dioxide between alveolar air and pulmonary capillary blood. (12 Dec 1998) |
| sister chromatid exchange | An aberrant crossing-over event in which there is an exchange of segments between the sister chromatids of a chromosome, either between the sister chromatids of a meiotic tetrad or between the sister chromatids of a duplicated somatic chromosome. It can be induced by ultraviolet and ionizing radiation or by mutagenic agents and is observed by autoradiography. (12 Dec 1998) |
| needle-exchange programs | Organised services for exchange of sterile needles and syringes used for injections as a potential means of reducing the transmission of infectious diseases. (12 Dec 1998) |
| international educational exchange | The exchange of students or professional personnel between countries done under the auspices of an organization for the purpose of further education. (12 Dec 1998) |
| exchange | 1. To part with give, or transfer to another in consideration of something received as an equivalent; usually followed by for before the thing received. "Exchange his sheep for shells, or wool for a sparking pebble or a diamond." (Locke) 2. To part with for a substitute; to lay aside, quit, or resign (something being received in place of the thing with); as, to exchange a palace for cell. "And death for life exchanged foolishly." (Spenser) "To shift his being Is to exchange one misery with another." (Shak) 3. To give and receive reciprocally, as things of the same kind; to barter; to swap; as, to exchange horses with a neighbor; to exchange houses or hats. "Exchange forgiveness with me, noble Hamlet." (Shak) Synonym: To barter, change, commute, interchange, bargain, truck, swap, traffic. Origin: Cf.OF. Eschangier, F. Echanger. See Exchange. 1. The act of giving or taking one thing in return for another which is regarded as an equivalent; as, an exchange of cattle for grain. 2. The act of substituting one thing in the place of another; as, an exchange of grief for joy, or of a scepter for a sword, and the like; also, the act of giving and receiving reciprocally; as, an exchange of civilities or views. 3. The thing given or received in return; especially, a publication exchanged for another. 4. The process of setting accounts or debts between parties residing at a distance from each other, without the intervention of money, by exchanging orders or drafts, called bills of exchange. These may be drawn in one country and payable in another, in which case they are called foreign bills; or they may be drawn and made payable in the same country, in which case they are called inland bills. The term bill of exchange is often abbreviated into exchange; as, to buy or sell exchange. A in London is creditor to B in new York, and C in London owes D in New York a like sum. A in London draws a bill of exchange on B in New York; C in London purchases the bill, by which A receives his debt due from B in New York. C transmits the bill to D in New York, who receives the amount from B. 5. A mutual grant of equal interests, the one in consideration of the other. Estates exchanged must be equal in quantity, as fee simple for fee simple. 6. The place where the merchants, brokers, and bankers of a city meet at certain hours, to transact business. In this sense often contracted to 'Change. Arbitration of exchange. See Arbitration. Bill of exchange. See Bill. Exchange broker. See Broker. Par of exchange, the established value of the coin or standard of value of one country when expressed in the coin or standard of another, as the value of the pound sterling in the currency of France or the United States. The par of exchange rarely varies, and serves as a measure for the rise and fall of exchange that is affected by the demand and supply. Exchange is at par when, for example, a bill in new York, for the payment of one hundred pounds sterling in London, can be purchased for the sum. Exchange is in favor of a place when it can be purchased there at or above par. Telephone exchange, a central office in which the wires of any two telephones or telephone stations may be connected to permit conversation. Synonym: Barter, dealing, trade, traffic, interchange. Origin: OE. Eschange, eschaunge, OF. Eschange, fr. Eschangier, F. Echanger, to exchange; pref. Ex- out + F. Changer. See Change, and cf. Excamb. Source: Websters Dictionary (01 Mar 1998) |
| exchange transfusion | Removal of most of a patient's blood followed by introduction of an equal amount from donors. Synonym: exsanguination transfusion, substitution transfusion, total transfusion. (05 Mar 2000) |