| APNH | antiporter sodium-hydrogen ion |
|---|---|
| cH+ | hydrogen ion concentration |
| CIE | Canberra interview for the elderly; cellulose ion exchange; counter-current immunoelectrophoresis; c... |
| DIM | divalent ion metabolism; medium infective dose [Lat. dosis infectionis media] |
| FIM | field ion microscopy; functional independence measure |
| 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) |
| aberrant complex | An anomalous electrocardiographic complex, more specifically an abnormal ventricular complex caused by abnormal intraventricular conduction of a supraventricular impulse. (05 Mar 2000) |
| activated complex | <chemistry> State of highest energy during a reaction. When reactants form the activated complex, bond breaking and bond formation is occurring. Synonym: transition state. (09 Jan 1998) |
| AIDS dementia complex | <immunology> A frequent cerebral condition in people with AIDS that results in the loss of cognitive capacity, affecting the ability to function in a social or occupational setting. Its cause has not been determined exactly, but may result from HIV infection of cells in the brain or an inflammatory reaction to such infection. (09 Oct 1997) |
| aids-related complex | A prodromal phase of infection with the human immunodeficiency virus (HIV). Laboratory criteria separating aids-related complex (arc) from aids include elevated or hyperactive B-cell humoral immune responses, compared to depressed or normal antibody reactivity in aids; follicular or mixed hyperplasia in arc lymph nodes, leading to lymphocyte degeneration and depletion more typical of aids; evolving succession of histopathological lesions such as localization of kaposi's sarcoma, signaling the transition to the full-blown aids. (12 Dec 1998) |
| alpha-keto acid dehydrogenase complex | See: alpha-keto acid dehydrogenase. Anaerobic dehydrogenase, an enzyme (usually a pyridinoenzyme) catalyzing the transfer of hydrogen from some metabolite to some acceptor molecule (e.g., NAD+, cytochrome) other than oxygen; e.g., lactate dehydrogenase's, isocitrate dehydrogenase's, and others in EC class 1, excluding those listed under aerobic dehydrogenase. (05 Mar 2000) |
| alpha-ketoglutarate dehydrogenase complex | alpha-ketoglutarate dehydrogenase |
| amygdaloid complex | Almond-shaped group of basal nuclei anterior to the inferior horn of the lateral ventricle of the brain, within the temporal lobe. The amygdala is part of the limbic system. (12 Dec 1998) |