| nuclear atom | <physics, radiobiology> A concept or model of the atom characterised by the presence of a small, massive nucleus at its centre. (05 Mar 2000) |
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| nuclear bag | <cell biology> The aggregation of nuclei occurring in the nonstriated centre of an intrafusal muscle fibre of a neuromuscular spindle. (05 Mar 2000) |
| nuclear bag fibre | The largest type of intrafusal muscle fibre's in a neuromuscular spindle, containing a central aggregation of nuclei (nuclear bag). (05 Mar 2000) |
| nuclear binding energy | <physics> The difference between the total energy (= mc^2) of the bound nucleus, and the energies of the individual constituent particles (= sum of masses c^2). The nuclear binding energy per nucleon is a maximum for iron. Fusion releases energy because light nuclei are less tightly bound than medium-weight nuclei, and thus energy is liberated when they become more tightly bound after fusing. Fission releases energy for the same reason - heavy nuclei are also less tightly bound than medium-weight nuclei, and energy is liberated when heavy nuclei split into lighter nuclei. (09 Oct 1997) |
| nuclear bone scan | A nuclear medicine test that involves the introduction of a radioactive compound into the blood stream. The radioactive compound acts as a tracer and allows for the imaging of the bony skeleton. (27 Sep 1997) |
| nuclear cardiology | <radiology> Myocardial infarct imaging (Tc-99m PYP), myocardial perfusion imaging (Tl-201), blood pool (MUGA), first-pass studies (12 Dec 1998) |
| nuclear cataract | A cataract involving the nucleus. Synonym: hard cataract. (05 Mar 2000) |
| nuclear chain fibre | The shortest and most numerous type of intrafusal muscle fibre's in a neuromuscular spindle, containing a single row of centrally positioned nuclei. (05 Mar 2000) |
| nuclear chemistry | The science concerned with the chemistry of nuclear reactions and processes. (05 Mar 2000) |
| nuclear-cytoplasmic ratio | Ratio of volume of nucleus to volume of cytoplasm, fairly constant for a particular cell type and usually increased in malignant neoplasms. (05 Mar 2000) |
| nuclear energy | Energy released by nuclear fission or nuclear fusion. (12 Dec 1998) |
| nuclear envelope | <cell biology> Membrane system that surrounds the nucleus of eukaryotic cells. Consists of inner and outer membranes separated by perinuclear space and perforated by nuclear pores. The term should be used in preference to the term nuclear membrane which is potentially very confusing. (18 Nov 1997) |
| nuclear factor 1 | See: CTF. (18 Nov 1997) |
| nuclear family | A family composed of husband and wife with their children. (12 Dec 1998) |
| nuclear fission | Nuclear reaction in which the nucleus of a heavy atom such as uranium or plutonium is split into two approximately equal parts by a neutron, charged particle, or photon. (12 Dec 1998) |