| low affinity platelet factor IV | Cytokine, produced from platelet basic protein, that acts as a growth factor. (18 Nov 1997) |
|---|---|
| alactic oxygen debt | That part of the oxygen debt that is not lactacid oxygen debt; during recovery, stores of ATP and creatine phosphate must be replenished by oxidative metabolism, and a small amount of oxygen is also needed to restore the normal oxyhemoglobin levels throughout the circulating blood. (05 Mar 2000) |
| alveolar-arterial oxygen difference | The difference or gradient between the partial pressure of oxygen in the alveolar spaces and the arterial blood: P(A-a)02. Normally in young adults this value is less than 20 mm Hg. See: alveolar gas equation. (05 Mar 2000) |
| arteriovenous oxygen difference | <physiology> The difference in the oxygen content (in ml per 100 ml blood) between arterial and venous blood. (05 Mar 2000) |
| biochemical oxygen demand | The amount of oxygen aerobicorganisms need to carry out oxidative metabolism in watercontaining organic matter, such as sewage. (09 Oct 1997) |
| carbon-oxygen ligases | <enzyme> Enzymes that catalyze the joining of two molecules by the formation of a carbon-oxygen bond. Registry number: EC 6.1 (12 Dec 1998) |
| carbon-oxygen lyases | <enzyme> Enzymes that catalyze the cleavage of a carbon-oxygen bond by means other than hydrolysis or oxidation. Registry number: EC 4.2 (12 Dec 1998) |
| reactive oxygen species | Reactive intermediate oxygen species including both radicals and non-radicals. These substances are constantly formed in the human body and have been shown to kill bacteria and inactivate proteins, and have been implicated in a number of diseases. Scientific data exist that link the reactive oxygen species produced by inflammatory phagocytes to cancer development. (12 Dec 1998) |
| chemical oxygen demand | The amount of dissolved oxygen required to combine with chemicals in wastewater. A measure of the oxygen equivalent of that portion of organic matter that is susceptible to oxidation by a strong chemical oxidizing agent. (05 Dec 1998) |
| rubredoxin-oxygen oxidoreductase | <enzyme> Contains fad and a new type of haem; site of oxygen reduction to water by desulfovibrio gigas coupled with NADH oxidation Registry number: EC 1.9.3.- Synonym: rubredoxin oxidase (26 Jun 1999) |
| phosphorus-oxygen lyases | <enzyme> Enzymes that catalyze the cleavage of a phosphorus-oxygen bond by means other than hydrolysis or oxidation. Registry number: EC 4.6 (12 Dec 1998) |
| critical dissolved oxygen concentration | <biology> The minimum concentration of oxygen in the water needed for the growth of a culture which has been submerged, where oxygen is the limiting factor to the growth of the culture. (09 Oct 1997) |
| heavy oxygen | A stable oxygen isotope making up 0.20% of natural oxygen; used in mass spectrometry and in NMR studies of tissue. Synonym: heavy oxygen. (05 Mar 2000) |
| home oxygen therapy | A form of oxygen that is typically delivered via nasal cannula. Commonly provided to those with severe heart or lung disease. See: chronic obstructive pulmonary disease. (27 Sep 1997) |
| hyperbaric oxygen | High pressure oxygen, oxygen at a pressure greater than 1 atmosphere. See: hyperbaric oxygenation. Singlet oxygen, an excited or higher energy form of oxygen characterised by the spin of a pair of electrons in opposite directions, whereas electron spin is unidirectional in normal molecular oxygen Because of its great reactivity, singlet oxygen is a probable intermediate in most photo-oxidation reactions. Although it exists for no more than 0.1 sec, it may react with atmospheric pollutants to foster smog formation and may have harmful biological effects. Triplet oxygen, the normal unexcited state of O2 in the atmosphere, in which the unpaired pair of electrons are so displaced that their magnetic fields are oriented in the same direction, resulting in paramagnetism; each of the heat-generated spectral lines of such oxygen can be split by a magnetic field into a triplet. Compare: singlet oxygen. (05 Mar 2000) |