| contrast material | A substance that is introduced into or around a structure and, because of the difference in absorption of X-rays by the contrast medium and the surrounding tissues, allows radiographic visualisation of the structure. (18 Nov 1997) |
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| cross-reacting material | <haematology> A substance sufficiently different from a reference substance (R) to have a perceptibly different function from R but sufficiently similar to R that it reacts with anti-R antibodies; e.g., mutant factor VIII may be defective or even inert in coagulation and yet be immunologically identified as factor VIII. (05 Mar 2000) |
| dental material | Any material used in dentistry. (05 Mar 2000) |
| discharge of dredged material | Any addition of dredged material into the waters of the U.S. The term includes, without limitation, the addition of dredged material to a specified discharge site located in waters of the U.S. And the runoff or overflow from a contained land or water disposal area. Discharges of pollutants into waters of the U.S., resulting from the onshore subsequent processing of dredged material that is extracted from any commercial use (other than fill), are not included within this term and are subject to Section 402 of the CWA even though the extraction and deposit of such material may require a permit from the Corps of Engineers. The term does not include plowing, cultivating, seeding, and harvesting for the production of food, fibre, and forest products. The term does not include de minimis, incidental soil movement occurring during normal dredging operations. (09 Oct 1997) |
| discharge of fill material | The addition of fill material into waters of the U.S. The term generally includes, without limitation, the following activities: placement of fill that is necessary for the construction of any structure in a water of the U.S., the building of any structure or impoundment requiring rock, sand, dirt, or other material for its construction, site-development fills for recreational, industrial, commercial, residential, and other uses, causeways or road fills, dams and dikes, artificial islands, property protection and/or reclamation devices such as riprap, groins, seawalls, breakwaters, and revetments, beach nourishment, levees, fill for structures such as sewage treatment facilities, intake and outfall pipes associated with power plants and subaqueous utility lines, and artificial reefs. The term does not include plowing, cultivating, seeding, and harvesting for the production of food, fibre, and forest products. (09 Oct 1997) |
| iodinated contrast material | A substance that contains iodine that can be injected, swallowed or given as an enema for the purpose of diagnostics. Iodinated contrast is radiopaque. This means that conventional X-rays will highlight the course of the contrast in the body. (27 Sep 1997) |
| type material | <zoology> A collective term for all type specimens. Zoologists should ensure that such material is transferred as quickly as possible to public institutions where their safety is guaranteed and they are accessible to other workers. (09 Jan 1998) |
| unconsolidated parent material | <ecology> Material from which a soil develops. (09 Oct 1997) |
| fertile material | <physics> In nuclear physics, this refers to a nuclide which converts to fissile material upon neutron capture and subsequent radioactive decay. Examples include Uranium-238 and Thorium-232. (09 Oct 1997) |
| fill material | Any material used for the primary purpose of replacing an aquatic area with dry land or of changing the bottom elevation of a waterbody. The term does not include any pollutant discharged into the water primarily to dispose of waste. (09 Oct 1997) |
| fissile material | <radiobiology> Material containing a large number of easily fissionable nuclei which give off multiple neutrons in the fission process. Usual meaning is that if a sufficiently large amount of fissile material is put together, a fission chain reaction can occur. Sometimes used synonymously with fissionable material, i.e., material that can be fissioned (though often under restricted circumstances, such as only with thermal (slow) neutrons). A more restricted meaning use of fissile material limits the concept to those materials which can be fissioned by neutrons of all energies (fast & slow). Examples include Uranium-235 and Plutonium-239. (09 Oct 1997) |
| basilar impression | An invagination of the base of the skull into the posterior fossa with compression of the brainstem and cerebellar structures into the foramen magnum. Compare: platybasia. (05 Mar 2000) |
| cardiac impression of liver | A depression on the superior area of the diaphragmatic surface of the liver corresponding to the position of the heart. Synonym: impressio cardiaca hepatis. (05 Mar 2000) |
| cardiac impression of lung | The depression on the medial surface of each lung produced by the presence of the heart. It is more pronounced on the left lung. Synonym: impressio cardiaca pulmonis. (05 Mar 2000) |
| gastric impression | A hollow on the visceral surface of the left lobe of the liver corresponding to the location of the stomach. Synonym: impressio gastrica. (05 Mar 2000) |