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Oxygen
An element with atomic symbol O, atomic number 8, and atomic weight [15.99903; 15.99977]. It is the most abundant element on earth and essential for respiration.
Year introduced: 1963
Biological Oxygen Demand Analysis
Testing for the amount of biodegradable organic material in a water sample by measuring the quantity of oxygen consumed by biodegradation of those materials over a specific time period.
Year introduced: 2011
Singlet Oxygen
An excited state of molecular oxygen generated photochemically or chemically. Singlet oxygen reacts with a variety of biological molecules such as NUCLEIC ACIDS; PROTEINS; and LIPIDS; causing oxidative damages.
Year introduced: 2002
Phosphorus-Oxygen Lyases
Enzymes that catalyze the cleavage of a phosphorus-oxygen bond by means other than hydrolysis or oxidation. EC 4.6.
Year introduced: 1998
Carbon-Oxygen Lyases
Enzymes that catalyze the cleavage of a carbon-oxygen bond by means other than hydrolysis or oxidation. EC 4.2.
Carbon-Oxygen Ligases
Enzymes that catalyze the joining of two molecules by the formation of a carbon-oxygen bond. EC 6.1.
Oxygen Compounds
Inorganic compounds that contain oxygen as an integral part of the molecule.
Reactive Oxygen Species
Molecules or ions formed by the incomplete one-electron reduction of oxygen. These reactive oxygen intermediates include SINGLET OXYGEN; SUPEROXIDES; PEROXIDES; HYDROXYL RADICAL; and HYPOCHLOROUS ACID. They contribute to the microbicidal activity of PHAGOCYTES, regulation of SIGNAL TRANSDUCTION and GENE EXPRESSION, and the oxidative damage to NUCLEIC ACIDS; PROTEINS; and LIPIDS.
Year introduced: 1993
Oxygen Radioisotopes
Unstable isotopes of oxygen that decay or disintegrate emitting radiation. O atoms with atomic weights 13, 14, 15, 19, and 20 are radioactive oxygen isotopes.
Year introduced: 1975
Oxygen Isotopes
Stable oxygen atoms that have the same atomic number as the element oxygen, but differ in atomic weight. O-17 and 18 are stable oxygen isotopes.
Oxygen Inhalation Therapy
Inhalation of oxygen aimed at restoring toward normal any pathophysiologic alterations of gas exchange in the cardiopulmonary system, as by the use of a respirator, nasal catheter, tent, chamber, or mask. (From Dorland, 27th ed and Stedman, 25th ed)
Oxygen Consumption
The rate at which oxygen is used by a tissue; microliters of oxygen STPD used per milligram of tissue per hour; the rate at which oxygen enters the blood from alveolar gas, equal in the steady state to the consumption of oxygen by tissue metabolism throughout the body. (Stedman, 25th ed, p346)
Year introduced: 1966
Oxygen Saturation
Extent to which HEMOGLOBIN is saturated with OXYGEN typically as measured in arterial blood. It can be measured by various methods (e.g., PULSE OXYMETER, blood gas analysis). A low blood oxygen saturation level indicates a condition called HYPOXEMIA.
Year introduced: 2022
Oxygen Radical Absorbance Capacity
A measure of the ability of a substance, such as a food, to quench oxygen free radicals in vitro.
Year introduced: 2017
Hyperbaric Oxygenation
The therapeutic intermittent administration of oxygen in a chamber at greater than sea-level atmospheric pressures (three atmospheres). It is considered effective treatment for air and gas embolisms, smoke inhalation, acute carbon monoxide poisoning, caisson disease, clostridial gangrene, etc. (From Segen, Dictionary of Modern Medicine, 1992). The list of treatment modalities includes stroke.
Year introduced: 1965(1964)
oxygen-regulated proteins [Supplementary Concept]
MW of 5 major ORPs are 260, 150, 100, 80 & 30kD; extreme hypoxia induces enhanced synthesis of ORPS; RefSeq NM_138867 (Orp150, rat); NM_006389 (HYOU1, human); NM_021395 (Hyou1, mouse)
Date introduced: October 29, 1986
Hypoxia
Sub-optimal OXYGEN levels in the ambient air of living organisms.
Year introduced: 2017 (1966)
Photosystem II Protein Complex
A large multisubunit protein complex found in the THYLAKOID MEMBRANE. It uses light energy derived from LIGHT-HARVESTING PROTEIN COMPLEXES to catalyze the splitting of WATER into DIOXYGEN and of reducing equivalents of HYDROGEN.
Year introduced: 2004
Lipoxygenase
An enzyme of the oxidoreductase class primarily found in PLANTS. It catalyzes reactions between linoleate and other fatty acids and oxygen to form hydroperoxy-fatty acid derivatives.
Year introduced: 1992
high-potential iron-sulfur protein oxygen oxidoreductase [Supplementary Concept]
a member of the heme-copper oxidase superfamily; GenBank AJ249578
Date introduced: January 31, 2001