| RI | radiation intensity; radioactive isotope; radioimmunology; recession index; recombinant inbred [stra... |
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| RIHSA | radioactive iodinated human serum albumin |
| RISA | radioactive iodinated serum albumin; radioimmunosorbent assay |
| RIU | radioactive iodine uptake |
| ALEC | artificial lung-expanding compound |
| acyclic compound | An organic compound in which the chain does not form a ring. Synonym: aliphatic compound, open chain compound. (05 Mar 2000) |
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| addition compound | Strictly, a complex of two or more complete molecules in which each preserves its fundamental structure and no covalent bonds are made or broken (e.g., hydrates of salts, adducts), loosely, association of acids with basic organic compound's (e.g., amines with HCl), more loosely, addition of two molecules without loss of any atom, but forming new covalent bonds (e.g., CH2==CH2 + Br2 → BrCH2-CH2Br). (05 Mar 2000) |
| aliphatic compound | An organic compound in which the chain does not form a ring. Synonym: aliphatic compound, open chain compound. (05 Mar 2000) |
| APC compound | An analgesic tablet drug combination containing aspirin, phenacetin and caffeine. Very widely used in the 1940's through 1960's; original constituents of popular over-the-counter pain remedies. Use currently much diminished due to concerns about potential renal injury due to the phenacetin. (05 Mar 2000) |
| aromatic compound | Any compound in which the constituent atoms, or any part of them, form a ring. Used mainly in organic chemistry where: 1) numerous compound's contain rings of carbon atoms (carbocyclic compound's) or carbon atoms plus one or more atoms of other types (heterocyclic compound's), usually nitrogen, oxygen, or sulfur; 2) where the atoms in the ring are all of the same element (homocyclic or isocyclic compound); 3) where the ring is saturated or contains nonconjugated double bonds (alicyclic compound), the compound is similar in properties to the corresponding acyclic compound (e.g., cyclohexane resembles hexane); 4) where the ring contains conjugated double bonds in a closed loop in which there are 4n + 2 (where n is an integer) delocalised π electrons (Huckel's rule) (aromatic compound; e.g., benzene, pyridine), it is more stable than the corresponding saturated ring and exhibits unusual chemical properties characteristic of itself and not of other types of rings or of acyclic compound's. These aromatic compounds have the ability to sustain an induced ring current. Synonym: closed chain compound, ring compound. (05 Mar 2000) |
| binary compound | <chemistry> This refers to any compound that is composed of only two elements. (09 Oct 1997) |
| calcium compound | Inorganic compounds that contain calcium as an integral part of the molecule. (12 Dec 1998) |
| carbamino compound | Any carbamic acid derivative formed by the combination of carbon dioxide with a free amino group to form an N-carboxy group, -NH-COOH, as in haemoglobin forming carbaminohemoglobin. (05 Mar 2000) |
| carbocyclic compound | See: cyclic compound. (05 Mar 2000) |
| genetic compound | In medical genetics, the presence of two different mutant alleles at the same loci. Synonym: genetic compound. (05 Mar 2000) |
| Reichstein's compound | One of several steroids; e.g., Reichstein's substance F (cortisone), Reichstein's substance H (corticosterone), Reichstein's substance M (cortisol), Reichstein's substance Q (cortexone), and Reichstein's substance S (cortexolone). Synonym: Reichstein's compound. (05 Mar 2000) |
| glycosyl compound | The compound formed between a sugar and another organic substance in which the OH of the reducing (hemiacetal) group of the former is removed; e.g., the natural nucleosides, in which a heterocyclic N becomes linked directly to the C-1 of ribose (or deoxyribose) to yield ribosyl compounds. Compare: glycoside. (05 Mar 2000) |
| gold compound | <pharmacology> A group of medications which act to suppress inflammation in synovial tissue. Examples include gold sodium thiomalate, auranofin and aurothioglucose. These medications are indicated in the treatment of rheumatoid arthritis, psoriatic arthritis, Felty's syndrome and juvenile rheumatoid arthritis. (27 Sep 1997) |
| meso compound | <chemistry> A compound that has two or more chiral centres but does not rotate plane-polarized light because it has an internal plane of symmetry. These compounds are identical to their mirror images. (09 Jan 1998) |
| chiral compound | <chemistry> A molecule that has an asymmetric centre and can be found in twonon-superimposable mirror-image forms (enantiomers). (05 Jan 1998) |