| naso-occipital arc | The arc in the midline from the root of the nose to the inferior limit of the external occipital protuberance. (05 Mar 2000) |
|---|---|
| interauricular arc | A line carried over the cranium from the centre of one external auditory meatus to that of the other. Synonym: interauricular arc. (05 Mar 2000) |
| unipolar arc | <radiobiology> Arc between a metal surface and a plasma in contact with it. Such an arc requires only one electrode and is maintained by the thermal energy of the electrons. (09 Oct 1997) |
| flame arc | An arc between two impregnated electrodes that causes volatilization of the core with resultant flame. (05 Mar 2000) |
| longitudinal arc of skull | The line carried over the skull in the midline from the nasion to the opisthion. (05 Mar 2000) |
| active carbon dioxide | Activated carbon dioxide, a complex of N-carboxybiotin (biotin + CO2) and an enzyme; the form in which carbon dioxide is added to other molecules in carboxylations; e.g., to methylcrotonyl-CoA to form beta-methylglutaconyl in the catabolism of leucine, and to acetyl-CoA to form malonyl-CoA. See: acetyl-CoA carboxylase. (05 Mar 2000) |
| anomeric carbon | The reducing carbon of a sugar; C-1 of an aldose, C-2 of a 2-ketose. (05 Mar 2000) |
| arteriovenous carbon dioxide difference | <physiology> The difference in carbon dioxide content (in ml per 100 ml blood) between arterial and venous blood. (05 Mar 2000) |
| carbon | <chemistry, element> Sixth element (Z=6) in the periodic table, has 6 protons, often described as the basis of life on earth because of its chemical properties, has potential for use with silicon as a low-activation structural material for fusion reactors, in the form silicon carbide. Carbon tiles are often used in plasma-facing components because its low Z makes carbon a relatively nice impurity. It is also useful as a neutron moderator. See: low-activation materials, plasma-facing components. Abbreviation: C (13 Nov 1997) |
| carbon-11 | A cyclotron-produced, positron-emitting radioisotope of carbon with a half-life of 20.3 minutes; used in positron-emitting tomography. (05 Mar 2000) |
| carbon-12 | The standard of atomic mass, 98.90% of natural carbon. (05 Mar 2000) |
| carbon-13 | A stable natural isotope, 1.1% of natural carbon. (05 Mar 2000) |
| carbon-14 | A beta-emitter with a half-life of 5715 years, widely used as a tracer in studying various aspects of metabolism; naturally occurring 14C, arising from cosmic ray bombardment, is used to date relics containing natural carbonaceous materials. (05 Mar 2000) |
| carbon bisulfide | <chemical> Carbon disulfide (cs2). A colourless, flammable, poisonous liquid, cs2. It is used as a solvent, and is a counterirritant and has local anaesthetic properties but is not used as such. It is highly toxic with pronounced CNS, haematologic, and dermatologic effects. Chemical name: Carbon disulfide (12 Dec 1998) |
| carbon compounds, inorganic | Inorganic compounds that contain carbon as an integral part of the molecule but are not derived from hydrocarbons. (12 Dec 1998) |