| cation | <chemistry> A positively-charged ion. (16 Mar 1998) |
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| 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 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) |
| cation exchanger | An insoluble solid (usually a polystyrene or a polysaccharide) that has negatively charged radicals attached to it (e.g., -COO-, -SO3-), which can attract and hold cations that pass by in a moving solution if these are more attracted to the acid groups than the counter ion present. (05 Mar 2000) |
| cation exhange resin | <chemistry> An insoluble resin with fixed anionic groups which is used in chromatography to separate cationic molecules. (16 Mar 1998) |
| cation-anion difference | <biochemistry> The difference between the sum of the measured cations and anions in the plasma or serum calculated as follows: (Na + K) -(Cl + HCO3) = < 20 mmol/l. Elevated values may occur in diabetic or lactic acidosis; normal or low values occur in bicarbonate-losing metabolic acidoses. Synonym: cation-anion difference. (05 Mar 2000) |
| cation-exchange resin | See: cation exchange, cation exchanger. (05 Mar 2000) |
| cationic | Referring to positively charged ions and their properties. (05 Mar 2000) |
| cationic detergents | Detergent's, such as the amine salts or quaternary ammonium or pyridinium compounds of long-chain fatty acids, that have positively charged groups attached to the larger hydrophobic portions. (05 Mar 2000) |
| cationic protein | <biochemistry> Proteins of azurophil granules of neutrophils, rich in arginine. A chymotrypsin like protease found in azurophil granules is also very cationic as is cathepsin G and neutrophil elastase. Eosinophil cationic protein (21 kD) is particularly important because it damages schistosomula in vitro. (16 Mar 1998) |
| cationised ferritin | <chemical> Ferritin, treated with dimethyl propanediamine and used to show, in the electron microscope, the distribution of negative charge on the surface of a cell. The amount of cationic ferritin binding is very approximately related to the surface charge. (16 Mar 1998) |
| cationogen | A substance that gives rise to positively charged ions. (05 Mar 2000) |
| cations | Postively charged atoms, radicals or groups of atoms which travel to the cathode or negative pole during electrolysis. (12 Dec 1998) |
| cations, divalent | Positively charged atoms, radicals or groups of atoms with a valence of plus 2, which travel to the cathode or negative pole during electrolysis. (12 Dec 1998) |
| cations, monovalent | Positively charged atoms, radicals or group of atoms with a valence of plus 1, which travel to the cathode or negative pole during electrolysis. (12 Dec 1998) |