| 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) |
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| 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) |
| nuclear fusion | Thermonuclear reaction in which the nuclei of an element of low atomic weight unite under extremely high temperature and pressure to form a nucleus of a heavier atom. (12 Dec 1998) |
| nuclear heart scan | This noninvasive test uses radioactive tracers to delineate the hearts chambers and major vessels. It may be used to detect a heart attack, heart muscle function and coronary artery disease. The patient receives a radioactive tracer by injection (into a vein) and then the heart is imaged using a gamma camera. The heart is imaged before and after exercise. This test may be used to detect and evaluate atrial septal defect, dilated cardiomyopathy, congestive heart failure, cardiomyopathy, Lyme disease (secondary), mitral stenosis and superior vena cava syndrome. (27 Sep 1997) |
| nuclear hyaloplasm | The presumably fluid substance or gel of the nucleus in which stainable elements were believed to be suspended; much that was formerly considered to be karyolymph is now known to be euchromatin. Synonym: nuclear hyaloplasm, nuclear sap, nucleochylema, nucleochyme. Origin: karyo-+ L. Lympha, clear water (05 Mar 2000) |