| Crookes-Hittorf tube | A simple evacuated tube containing a cathode, that emitted X-rays from the glass envelope when a current was passed through it; the type used by Roentgen to discover X-rays. (05 Mar 2000) |
|---|---|
| crop gland | Cells in the crop of male and female pigeons and doves that secrete a caseous or milklike material with which the bird feeds its young; it is stimulated to secrete by prolactin, the lactogenic hormone of the anterior hypophysis, and is used as a test object for assaying the activity of this hormone. (05 Mar 2000) |
| crop milk | A secretion formed by glands in the mucosa of the pigeon's crop with which the young are fed; it is increased under the influence of prolactin. Synonym: crop milk. (05 Mar 2000) |
| crop tree | Usually a conifer tree grown to provide wood products. (05 Dec 1998) |
| crops, agricultural | Cultivated plants or agricultural produce such as grain, vegetables, or fruit. (12 Dec 1998) |
| Crosby capsule | An attachment to the end of a flexible tube, used for peroral biopsy of the small intestine, by which a piece of mucosa is sucked into an opening in the capsule and cut off. (05 Mar 2000) |
| Crosby, William Holmes Jr | <person> U.S. Physician, *1914. See: Crosby capsule. (05 Mar 2000) |
| cross | 1. Any figure in the shape of a cross formed by two intersecting lines. Synonym: crux. Synonym: crux of heart. 3. A method of hybridization or the hybrid so produced. Origin: F. Croix, L. Crux (05 Mar 2000) |
| cross agglutination | Agglutination by antibodies specific for minor (group) antigens common to several microorganisms, each of which possesses its own major specific antigen. Synonym: cross agglutination. (05 Mar 2000) |
| cross circulation | The circulation in a portion of the body of one individual of blood supplied from another individual. (12 Dec 1998) |
| 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) |
| cross flap | A skin flap transferred from one part of the body to a corresponding part, as from one arm to the other. (05 Mar 2000) |
| cross hybridization | Annealing of a DNA probe to an imperfectly matching DNA molecule. (05 Mar 2000) |
| cross infection | <microbiology> Infection transmitted between individuals infected with different pathogenic microorganisms. Any infection which a patient contracts in a health-care institution. (12 Dec 1998) |
| cross linking | 1. <chemistry> The linking of the chains of a polymer to one another so that the polymer, as a network, becomes stronger and more resistant to being dissolved. 2. <molecular biology> The abnormal linking of two strands of DNA by covalent bonds (as opposed to the normal hydrogen bonds between base pairs), which can occur by exposure to X-rays. Such linking is a type of damage to the DNA molecule and must be repaired before the DNA can replicate and function properly again. (09 Oct 1997) |