| FU | fecal urobilinogen; fetal urobilinogen; fluorouracil; follow-up; flux unit [ion]; fractional urinaly... |
|---|---|
| H+ | hydrogen ion |
| [H+] | hydrogen ion concentration |
| HEIS | high-energy ion scattering |
| ICM | inner cell mass; integrated conditional model; intercostal margin; International Confederation of Mi... |
| 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) |
| carotid artery, common | The two principal arteries supplying the structures of the head and neck. They ascend in the neck, one on each side, and at the level of the upper border of the thyroid cartilage, each divides into two branches, the external (carotid artery, external) and internal (carotid artery, internal) carotid arteries. (12 Dec 1998) |
| migraine, common | Migraine without aura. The most frequent type, accounting for about 80-85% of migraines. See migraine. (12 Dec 1998) |
| cold, common | A viral upper respiratory tract infection. A contagious illness caused by a number of different types of viruses. Because of the great number of viruses that can cause a cold, the body never builds up resistance (immune) against all of them. For this reason, colds are a frequent and recurring problem. In fact, preschool children average 9 colds a year; those in kindergarten, 12 colds a year; and adolescents and adults, 7 colds per year. Going out into the cold weather has no effect on the spread of a cold. Antibiotics do not help the common cold. (12 Dec 1998) |
| common acute lymphoblastic leukaemia | <haematology, oncology> A sub-type of acute lymphoblastic leukaemia affecting cells early in the B lymphocyte lineage which accounts for about 80% of all acute lymphoblastic leukaemia. Origin: Gr. Haima = blood (13 Nov 1997) |
| common antigen | Cross reacting antigen (epitope), a common antigen that occurs in 2 or more different molecules/organisms. Synonym: heterogenic enterobacterial antigen. (05 Mar 2000) |
| common baldness | Hair loss in women that may be associated with aging, hormones (androgens) or genetic predisposition. The pattern of baldness in women is different from that of men. In women there is thinning of the hair all over the scalp, but the frontal hairline is maintained. The hair loss is usually permanent. Treatment has been successful with topical minoxidil in some cases. (27 Sep 1997) |
| common basal vein | <anatomy, vein> The tributary to the inferior pulmonary vein (right and left) that receives blood from the superior and inferior basal veins. Synonym: vena basalis communis. (05 Mar 2000) |