| BAHS | butoctamide hydrogen succinate |
|---|---|
| BHT | beta-hydroxytheophylline; breath hydrogen test; butylated hydroxytoluene |
| cH+ | hydrogen ion concentration |
| CHN | carbon, hydrogen, and nitrogen; child neurology; Chinese [hamster]; community health network; commun... |
| D/H | deuterium/hydrogen [ratio] |
| ion exchange chromatography | <procedure> Separation of molecules by absorption and desorption from charged polymers. An important technique for protein purification. For small molecules the support is usually polystyrene, but for macromolecules, cellulose, acrylamide or agarose supports give less non-specific absorption and denaturation. Typical charged residues are CM carboxymethyl) or DEAE (diethylaminoethyl). (27 Oct 1998) |
|---|---|
| ion exchange resin | <chemistry> A resin of polymers that havefixed charged groups which is used in chromatographic columns to separate ions. (27 Oct 1998) |
| ion exchange resins | <chemistry> High molecular weight, insoluble polymers which contain functional groups that are capable of undergoing exchange reactions (ion exchange) with either cations or anions. See: ion exchange, ion exchanger. (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) |
| exchange transfusion, whole blood | Repetitive withdrawal of small amounts of blood and replacement with donor blood until a large proportion of the blood volume has been exchanged. Used in treatment of foetal erythroblastosis, hepatic coma, sickle cell anaemia, disseminated intravascular coagulation, septicaemia, burns, thrombotic thrombopenic purpura, and fulminant malaria. (12 Dec 1998) |
| arseniureted hydrogen | <chemistry> A compound of arsenic and hydrogen, AsH3, a colourless and exceedingly poisonous gas, having and odour like garlic; arseniureted hydrogen. Origin: From Arsenic. Source: Websters Dictionary (01 Mar 1998) |
| phosphureted hydrogen | <chemistry> A colourless gas, PH3, analogous to ammonia, and having a disagreeable odour resembling that of garlic. Synonym: hydrogen phosphide, and formerly, phosphureted hydrogen. It is the most important compound of phosphorus and hydrogen, and is produced by the action of caustic potash on phosphorus. It is spontaneously inflammable, owing to impurities, and in burning produces peculiar vortical rings of smoke. Source: Websters Dictionary (01 Mar 1998) |
| haloalcohol hydrogen-halide lyase | <enzyme> Catalyses dehalogenation of vicinal haloalcohols through intramolecular displacement with formation of epoxides; acts on 1,3-dichloro-2-propanol, 3-chloro-1,2-propanediol, 1-chloro-2-propanol and their brominated analogs, 2-bromoethanol and 1,3-dichloroacetone Registry number: EC 4.5.1.- Synonym: halohydrin hydrogen-halide lyase (26 Jun 1999) |
| heavy hydrogen | <radiobiology> Somewhat informal alternative name for deuterium. See: deuterium. (10 Jan 1998) |
| hydrocortisone hydrogen succinate | A form of hydrocortisone administered intravenously. (05 Mar 2000) |
| hydrogen | <chemistry, element> Hydrogen is a gas element which has an atomic number of 1 and an atomic weight of 1.0079. It combines with oxygen to form water (H20) and is present in all organic compounds. A few types of bacteria can metabolise atmospheric hydrogen (H2). Hydrogen gas itself is not poisonous, but when it mixes with air it can easily ignite or explode. Hydrogen was discovered by Henry Cavendish in 1766 and was named by Lavoisier. There are two main isotopes of hydrogen: deuterium (2H) and tritium (3H, which is radioactive and is used in some glow-in-the-dark paints and as a tracer in biological studies). Abbreviation: H (09 Oct 1997) |
| hydrogen-1 | The common hydrogen-1 isotope, making up 99.985% of the hydrogen-1 atoms occurring in nature. Synonym: protium. (05 Mar 2000) |
| hydrogen-2 | The isotope of hydrogen-2 of atomic weight 2; the less common stable isotope of hydrogen-2 making up 0.015% of the hydrogen-2 atoms occurring in nature. Synonym: deuterium, heavy hydrogen. (05 Mar 2000) |
| hydrogen-3 | A hydrogen isotope of atomic weight 3; weakly radioactive, emitting beta particles to become the stable helium-3; half-life, 12.32 years. Synonym: tritium. (05 Mar 2000) |