| blood-testis barrier | The membrane in the testis that separates sperm from the bloodstream. (09 Oct 1997) |
|---|---|
| placental barrier | The semipermeable layer of foetal tissue separating the maternal from the foetal blood in the placenta; composed of: 1) endothelium of the foetal vessels in the chorionic villi, 2) stromata of the villi, 3) cytotrophoblast (negligible after the fifth month of gestation), and 4) syncytial trophoblast covering the villi; the placental membrane acts as a selective membrane regulating passage of substances from the maternal to the foetal blood. Synonym: placental barrier. (05 Mar 2000) |
| incest barrier | In psychoanalysis, the learning or internalization of parental and social prohibitions against incest. (05 Mar 2000) |
| thermal barrier | <radiobiology> In magnetic mirror devices, this is a depression of electrostatic potential formed by enhancing ion loss in the region between the central cell and the positive potential plug. The thermal barrier significantly reduces the density requirements in the plug and lowers the overall power required to sustain the solenoidal plugging by thermally decoupling central cell electrons from the end plugs. (09 Oct 1997) |
| absorbable gelatin film | A sterile, nonantigenic, absorbable, water-insoluble, thin sheet of gelatin prepared by drying a gelatin-formaldehyde solution on plates; used in the closure and repair of defects in membranes such as the dura mater or the pleura; it undergoes absorption over a period of 1 to 6 months. (05 Mar 2000) |
| bitewing film | A special packaging of radiographic film that allows appendage of the film package to be held between the occlusal surfaces of the teeth. (05 Mar 2000) |
| gallium uptake with normal chest film | <radiology> Pulmonary drug toxicity, tumour infiltration, sarcoidosis, pneumocystis carinii see: lung: gallium imaging (12 Dec 1998) |
| panoramic X-ray film | In dentistry, a radiograph taken to give a panoramic view of the entire upper and lower dental arch as well as the temporomandibular joints. (05 Mar 2000) |
| rapid film changer | A device that moves film for radiographic studies that require rapid serial X-ray exposures, such as angiography. Synonym: rapid film changer, serial film changer. (05 Mar 2000) |
| chest film | most common X-ray used to detect abnormalities in or within the thoracic cage, such as the lungs, heart, aorta, and the bones of the chest. Extra metallic objects, such as jewelry are removed from the chest and neck areas for a chest X-ray to avoid interference with x-ray penetration and improve accuracy of the interpretation. (12 Dec 1998) |
| right or left lateral decubitus film | A radiograph exposed with the subject in the decubitus position; named for the side that is dependent. Synonym: right or left lateral decubitus film. (05 Mar 2000) |
| plain film | A radiograph made without use of a contrast medium. (05 Mar 2000) |
| wide-latitude film | Film that does not show large contrast differences with differences in exposure; the slope of the H and D curve is low. Synonym: latitude film. (05 Mar 2000) |
| precorneal film | A protective film, 7 to 9 nm thick, consisting of external oily, intermediate watery, and deep mucoprotein layers. Synonym: tear film. (05 Mar 2000) |
| X-ray film | A film base coated with an emulsion designed for use with X-rays. (12 Dec 1998) |