| DCX | double charge exchange |
|---|---|
| e | base of natural logarithms, approximately 2.7182818285; egg transfer; ejection; electric charge; ele... |
| ET | educational therapy; effective temperature; ejection time; embryo transfer; endothelin; endotoxin; e... |
| EVFMG | exchange visitor foreign medical graduate |
| exch | exchange |
| ion selective electrode | An electrode half cell, with a semi permeable membrane that is permeable only to a single ion. The electrical potential measured between this and a reference half cell (e.g. A calomel electrode) is thus the Nernst potential for the ion. Given that the solution filling the ion selective electrode is known, the activity (rather than concentration) of the ion in the unknown solution can be measured. Commercial ion selective electrodes frequently use a hydrophobic membrane containing an ionophore, such as valinomycin (for potassium) or monensin (for sodium). A pH electrode is made with a thin membrane of pH sensitive (i.e. Proton permeable) glass. (18 Nov 1997) |
|---|---|
| ion-selective electrodes | Electrodes which can be used to measure the concentration of particular ions in cells, tissues, or solutions. (12 Dec 1998) |
| ion transport | The movement of ions across energy-transducing cell membranes. Transport can be active or passive. Passive ion transport (facilitated diffusion) derives its energy from the concentration gradient of the ion itself and allows the transport of a single solute in one direction (uniport). Active ion transport is usually coupled to an energy-yielding chemical or photochemical reaction such as ATP hydrolysis. This form of primary active transport is called an ion pump. Secondary active transport utilises the voltage and ion gradients produced by the primary transport to drive the cotransport of other ions or molecules. These may be transported in the same (symport) or opposite (antiport) direction. (12 Dec 1998) |
| oxonium ion | <chemistry> A positively charged ion that is water with an additional hydrogen atom (H3O). (09 Oct 1997) |
| tetraethylammonium ion | A monovalent cation widely used in neurophysiology as a specific blocker of potassium channels. It is similar in size to the hydrated potassium ion and gets stuck (reversibly) in the channels. (18 Nov 1997) |
| field ion microscope | <instrument> Type of microscopy in which the specimen is illuminated with ions, often gallium ions, that are focussed electrostatically. The ions remove components of the specimen, lower atomic masses first. These are imaged and provide information on elemental distribution with a resolution of perhaps 30 nm. (18 Nov 1997) |
| ligand gated ion channel | A transmembrane ion channel whose permeability is increased by the binding of a specific ligand, typically a neurotransmitter at a chemical synapse. The permeability change is often drastic, such channels let through effectively no ions when shut, but allow passage at up to 10exp7 ions sexp 1 when a ligand is bound. Recently, the receptors for both acetylcholine and GABA have been found to share considerable sequence homology, implying that there may be a family of structurally related ligand gated ion channels. (18 Nov 1997) |
| light-ion fusion | <radiobiology> Light-Ion-Beam-Driven Inertial Confinement fusion, using beams of light ions driven at implosion targets. Pulsed-power driven accelerators are relatively efficient and cost-effective, but beam-focusing is a technical hurdle for this approach. (09 Oct 1997) |
| acrylic resin | A general term applied to a resinous material of the various esters of acrylic acid; used as a denture base material, for other dental restorations, and for trays. (05 Mar 2000) |
| acrylic resin base | A form made of acrylic resin molded to conform to the tissues of the alveolar process and used to support the teeth of a prosthesis. (05 Mar 2000) |
| acrylic resin tooth | A tooth made of acrylic resin. (05 Mar 2000) |
| activated resin | Autopolymerizing resin, any resin that can be polymerised by chemical catalysis rather than by the application of heat; used in dentistry for dental restoration, denture repair, and impression trays. Synonym: activated resin, cold cure resin, cold-curing resin, quick cure resin, self-curing resin. (05 Mar 2000) |
| autopolymer resin | Autopolymerizing resin, any resin that can be polymerised by chemical catalysis rather than by the application of heat; used in dentistry for dental restoration, denture repair, and impression trays. Synonym: activated resin, cold cure resin, cold-curing resin, quick cure resin, self-curing resin. (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) |
| resin | Any one of a class of yellowish brown solid inflammable substances, of vegetable origin, which are nonconductors of electricity, have a vitreous fracture, and are soluble in ether, alcohol, and essential oils, but not in water; specif, pine resin. Resins exude from trees in combination with essential oils, gums, etc, and in a liquid or semiliquid state. They are composed of carbon, hydrogen, and oxygen, and are supposed to be formed by the oxidation of the essential oils. Copal, mastic, quaiacum, and colophony or pine resin, are some of them. When mixed with gum, they form the gum resins, like asafetida and gamboge; mixed with essential oils, they frorm balsams, or oleoresins. <chemical> Highgate resin, a fossil resin resembling copal, occuring in blue clay at Highgate, near London. <botany> Resin bush, a low composite shrub (Euryops speciosissimus) of South Africa, having smooth pinnately parted leaves and abounding in resin. Origin: F. Resine, L. Resina; cf. Gr. Rhtinh. (10 Mar 1998) |