| radioactive contamination | <radiobiology> Radioactive substance dispersed in material or places where it is undesirable. (16 Dec 1997) |
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| food contamination | The presence in food of harmful, unpalatable, or otherwise objectionable foreign substances, e.g. Chemicals, microorganisms or diluents, before, during, or after processing or storage. (12 Dec 1998) |
| contamination | The soiling or pollution by inferior material, as by the introduction of organisms into a wound or sewage into a stream. Origin: L. Contaminatio from con =together + tangere = to touch (18 Nov 1997) |
| cross contamination | <dentistry> Passing bacteria or viruses indirectly from one patient to another through the use of improper sterilisation procedures, unclean instruments, or recycling of products. (08 Jan 1998) |
| specimen contamination | <microscopy> A change in the specimen caused by the condensation upon it of residual vapours in the microscope under the influence of electron bombardment. (05 Aug 1998) |
| direct contamination | <dentistry> Direct contact with impurities or germs. (for example by a patient sneezing on the assistant.) (08 Jan 1998) |
| equipment contamination | The presence of an infectious agent on instruments, prostheses, or other inanimate articles. (12 Dec 1998) |
| air pollutants, radioactive | Pollutants, present in air, which exhibit radioactivity. (12 Dec 1998) |
| radioactive | Giving off radiation. (12 Dec 1998) |
| radioactive atom | <chemistry, physics> An atom with an unstable nucleus, which emits particulate or electromagnetic radiation (radioactive emission) to achieve greater stability. See: radionuclide, half-life, Becquerel. (05 Mar 2000) |
| radioactive constant | <physics, radiobiology> The fraction of the amount of a radionuclide that undergoes transition per unit time. Formally: Lamda=dP/dt Where dP is the probability of a given nucleus undergoing spontaneous nuclear transition in the time interval dt. (16 Dec 1997) |
| radioactive cow | Colloquialism for radionuclide generator. See: cow. (05 Mar 2000) |
| radioactive decay | <physics> The process by which a spontaneous change in nuclear state takes place. This process is accompanied by the emission of energy in various specific combinations of electromagnetic and corpuscular radiation and neutrinos. (16 Dec 1997) |
| radioactive equilibrium | <radiobiology> That condition in which the activities of the members of a radioactive chain decrease exponentially in time with the half-life of the chain precursor. Such radioactive equilibrium is only possible when the half-life of the precursor is longer than that of any other chain member. If the precursor half-life is so long that the change in the precursor population during the period of interest can be ignored, all the activities become sensibly equal and the equilibrium is said to be secular, otherwise it is said to be transient. (16 Dec 1997) |
| radioactive fallout | The material that descends to the earth or water well beyond the site of a surface or subsurface nuclear explosion. (12 Dec 1998) |