| chromatography, ion exchange | Separation technique in which the stationary phase consists of ion exchange resins. The resins contain loosely held small ions that easily exchange places with other small ions of like charge present in solutions washed over the resins. (12 Dec 1998) |
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| ion exchange | Reversible chemical reaction between a solid, often an ion exchange resin, and a fluid whereby ions may be exchanged from one substance to another. This technique is used in water purification, in research, and in industry. (12 Dec 1998) |
| 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) |
| membranes | Thin layers of tissue which cover parts of the body, separate adjacent cavities, or connect adjacent structures. (12 Dec 1998) |
| membranes, artificial | Artificially produced membranes, such as semipermeable membranes used in artificial kidney dialysis, monomolecular and bimolecular membranes used as models to simulate biological membranes. These membranes are also used in the process of guided tissue regeneration. (12 Dec 1998) |
| pharyngeal membranes | Thin sheets, composed of ectoderm externally and endoderm internally, which separate the pharyngeal pouches from the overlying branchial clefts in the early embryo. Synonym: pharyngeal membranes. (05 Mar 2000) |
| closing membranes | Thin sheets, composed of ectoderm externally and endoderm internally, which separate the pharyngeal pouches from the overlying branchial clefts in the early embryo. Synonym: pharyngeal membranes. (05 Mar 2000) |
| mucous membranes | <pathology> A mucous membrane or tunica mucosa. (18 Nov 1997) |
| synaptic membranes | Cell membranes associated with synapses. Both presynaptic and postsynaptic membranes are included along with their integral or tightly associated specializations for the release or reception of transmitters. (12 Dec 1998) |
| intercostal membranes | The membranous layers between ribs. Synonym: membranae intercostalia, intercostal ligaments, ligamenta intercostalia. (05 Mar 2000) |
| intracellular membranes | Membranes of subcellular structures. (12 Dec 1998) |
| foetal membranes | Thin layers of tissue which surround the embryo or foetus and provide for its nutrition, respiration, excretion and protection; they are the yolk sac, allantois, amnion, and chorion. (12 Dec 1998) |
| foetal membranes, premature rupture | Spontaneous rupture of amniotic sac before the onset of uterine contractions. (12 Dec 1998) |