| displacements per atom | (dpa) This is a measure of the amount of radiation damage in neutron-irradiated materials, for example, 10 dpa means each atom in the material has been displaced from its site within the structural lattice of the material an average of 10 times (due to interactions between the atoms and the energetic neutrons irradiating the material.) (09 Oct 1997) |
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| ionised atom | <chemistry> An atom that possesses an electrostatic charge as a result of loss or gain of electrons; e.g., H+, Calcium, Cl-, O2-. (05 Mar 2000) |
| tagged atom | A radioactive atom, or a stable but rare one, which by its presence in a molecule helps localization or measurement of that molecule. Synonym: tagged atom. (05 Mar 2000) |
| excited atom | An atom possessing more than normal energy as a result of input of energy. See: excited state. Synonym: excited atom. (05 Mar 2000) |
| labelled atom | A radioactive atom, or a stable but rare one, which by its presence in a molecule helps localization or measurement of that molecule. Synonym: tagged atom. (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) |