A major group of unsaturated cyclic hydrocarbons containing two or more rings. The vast number of compounds of this important group, derived chiefly from petroleum and coal tar, are rather highly reactive and chemically versatile. The name is due to the strong and not unpleasant odor characteristic of most substances of this nature. (From Hawley's Condensed Chemical Dictionary, 12th ed, p96)

Cytoplasmic proteins that bind certain aryl hydrocarbons, translocate to the nucleus, and activate transcription of particular DNA segments. AH receptors are identified by their high-affinity binding to several carcinogenic or teratogenic environmental chemicals including polycyclic aromatic hydrocarbons found in cigarette smoke and smog, heterocyclic amines found in cooked foods, and halogenated hydrocarbons including dioxins and polychlorinated biphenyls. No endogenous ligand has been identified, but an unknown natural messenger with a role in cell differentiation and development is suspected.

Organic compounds containing carbon and hydrogen in the form of an unsaturated, usually hexagonal ring structure. The compounds can be single ring, or double, triple, or multiple fused rings.

Compounds consisting of two or more fused ring structures.

A chemical by-product that results from burning or incinerating chlorinated industrial chemicals and other hydrocarbons. This compound is considered an environmental toxin, and may pose reproductive, as well as, other health risks for animals and humans.

Aryl hydrocarbon receptor nuclear translocator is a basic HELIX-LOOP-HELIX MOTIF containing protein that forms a complex with DIOXIN RECEPTOR. The complex binds xenobiotic regulatory elements and activates transcription of a variety of genes including UDP GLUCURONOSYLTRANSFERASE. AhR nuclear translocator is also a subunit of HYPOXIA-INDUCIBLE FACTOR 1.

Hydrocarbon compounds with one or more of the hydrogens replaced by CHLORINE.

A liver microsomal cytochrome P-450 monooxygenase capable of biotransforming xenobiotics such as polycyclic hydrocarbons and halogenated aromatic hydrocarbons into carcinogenic or mutagenic compounds. They have been found in mammals and fish. This enzyme, encoded by CYP1A1 gene, can be measured by using ethoxyresorufin as a substrate for the ethoxyresorufin O-deethylase activity.

A potent mutagen and carcinogen. It is a public health concern because of its possible effects on industrial workers, as an environmental pollutant, an as a component of tobacco smoke.

A large group of cytochrome P-450 (heme-thiolate) monooxygenases that complex with NAD(P)H-FLAVIN OXIDOREDUCTASE in numerous mixed-function oxidations of aromatic compounds. They catalyze hydroxylation of a broad spectrum of substrates and are important in the metabolism of steroids, drugs, and toxins such as PHENOBARBITAL, carcinogens, and insecticides.

The generic name for the group of aliphatic hydrocarbons Cn-H2n+2. They are denoted by the suffix -ane. (Grant & Hackh's Chemical Dictionary, 5th ed)

Naturally occurring complex liquid hydrocarbons which, after distillation, yield combustible fuels, petrochemicals, and lubricants.

Four fused benzyl rings with three linear and one angular, that can be viewed as a benzyl-phenanthrenes. Compare with NAPHTHACENES which are four linear rings.

A group of condensed ring hydrocarbons.

A class of chemicals that contain an anthracene ring with a naphthalene ring attached to it.

Chlorinated hydrocarbons containing heteroatoms that are present as contaminants of herbicides. Dioxins are carcinogenic, teratogenic, and mutagenic. They have been banned from use by the FDA.

Elimination of ENVIRONMENTAL POLLUTANTS; PESTICIDES and other waste using living organisms, usually involving intervention of environmental or sanitation engineers.

Substances which pollute the soil. Use for soil pollutants in general or for which there is no specific heading.

A carcinogen that is often used in experimental cancer studies.

Organic compounds composed exclusively of carbon and hydrogen. Three or more carbon atoms are arranged in a cyclic structure and they possess aliphatic properties.

Substances or energies, for example heat or light, which when introduced into the air, water, or land threaten life or health of individuals or ECOSYSTEMS.

Organic compounds composed exclusively of carbon and hydrogen where no carbon atoms join to form a ring structure.

Complex petroleum hydrocarbons consisting mainly of residues from crude oil distillation. These liquid products include heating oils, stove oils, and furnace oils and are burned to generate energy.

Volative flammable fuel (liquid hydrocarbons) derived from crude petroleum by processes such as distillation reforming, polymerization, etc.

Chemical compounds which pollute the water of rivers, streams, lakes, the sea, reservoirs, or other bodies of water.

Substances that increase the risk of NEOPLASMS in humans or animals. Both genotoxic chemicals, which affect DNA directly, and nongenotoxic chemicals, which induce neoplasms by other mechanism, are included.

Release of oil into the environment usually due to human activity.

The products of chemical reactions that result in the addition of extraneous chemical groups to DNA.

1,2-Benzphenanthrenes. POLYCYCLIC COMPOUNDS obtained from coal tar.

The monitoring of the level of toxins, chemical pollutants, microbial contaminants, or other harmful substances in the environment (soil, air, and water), workplace, or in the bodies of people and animals present in that environment.

Organic compounds containing a BENZENE ring attached to a flavone group. Some of these are potent arylhydrocarbon hydroxylase inhibitors. They may also inhibit the binding of NUCLEIC ACIDS to BENZOPYRENES and related compounds. The designation includes all isomers; the 7,8-isomer is most frequently encountered.

Unsaturated hydrocarbons of the type Cn-H2n, indicated by the suffix -ene. (Grant & Hackh's Chemical Dictionary, 5th ed, p408)

A by-product of the destructive distillation of coal used as a topical antieczematic. It is an antipruritic and keratoplastic agent used also in the treatment of psoriasis and other skin conditions. Occupational exposure to soots, tars, and certain mineral oils is known to be carcinogenic according to the Fourth Annual Report on Carcinogens (NTP 85-002, 1985) (Merck Index, 11th ed).

An increase in the rate of synthesis of an enzyme due to the presence of an inducer which acts to derepress the gene responsible for enzyme synthesis.

Industrial products consisting of a mixture of chlorinated biphenyl congeners and isomers. These compounds are highly lipophilic and tend to accumulate in fat stores of animals. Many of these compounds are considered toxic and potential environmental pollutants.

A residue of coal, left after dry (destructive) distillation, used as a fuel.

A polyaromatic hydrocarbon inducer of P4501A1 and P4501A2 cytochromes. (Proc Soc Exp Biol Med 1994 Dec:207(3):302-308)

A microanalytical technique combining mass spectrometry and gas chromatography for the qualitative as well as quantitative determinations of compounds.

A concave exterior region on some POLYCYCLIC AROMATIC HYDROCARBONS that have three phenyl rings in a non-linear arrangement.

A greasy substance with a smoky odor and burned taste created by high temperature treatment of BEECH and other WOOD; COAL TAR; or resin of the CREOSOTE BUSH. It contains CRESOLS and POLYCYCLIC AROMATIC HYDROCARBONS which are CARCINOGENS. It has been widely used as wood preservative and in PESTICIDES and had former use medicinally in DISINFECTANTS; LAXATIVES; and DERMATOLOGIC AGENTS.

Carcinogenic substances that are found in the environment.

Tricyclic ethylene-bridged naphthalene derivatives. They are found in petroleum residues and coal tar and used as dye intermediates, in the manufacture of plastics, and in insecticides and fungicides.

A superfamily of hundreds of closely related HEMEPROTEINS found throughout the phylogenetic spectrum, from animals, plants, fungi, to bacteria. They include numerous complex monooxygenases (MIXED FUNCTION OXYGENASES). In animals, these P-450 enzymes serve two major functions: (1) biosynthesis of steroids, fatty acids, and bile acids; (2) metabolism of endogenous and a wide variety of exogenous substrates, such as toxins and drugs (BIOTRANSFORMATION). They are classified, according to their sequence similarities rather than functions, into CYP gene families (>40% homology) and subfamilies (>59% homology). For example, enzymes from the CYP1, CYP2, and CYP3 gene families are responsible for most drug metabolism.

Any substance in the air which could, if present in high enough concentration, harm humans, animals, vegetation or material. Substances include GASES; PARTICULATE MATTER; and volatile ORGANIC CHEMICALS.

A widely used industrial solvent.

Fractionation of a vaporized sample as a consequence of partition between a mobile gaseous phase and a stationary phase held in a column. Two types are gas-solid chromatography, where the fixed phase is a solid, and gas-liquid, in which the stationary phase is a nonvolatile liquid supported on an inert solid matrix.

The chemical alteration of an exogenous substance by or in a biological system. The alteration may inactivate the compound or it may result in the production of an active metabolite of an inactive parent compound. The alterations may be divided into METABOLIC DETOXICATION, PHASE I and METABOLIC DETOXICATION, PHASE II.

The outer covering of the body composed of the SKIN and the skin appendages, which are the HAIR, the NAILS; and the SEBACEOUS GLANDS and the SWEAT GLANDS and their ducts.

7,8,8a,9a-Tetrahydrobenzo(10,11)chryseno (3,4-b)oxirene-7,8-diol. A benzopyrene derivative with carcinogenic and mutagenic activity.

A family of isomeric, colorless aromatic hydrocarbon liquids, that contain the general formula C6H4(CH3)2. They are produced by the destructive distillation of coal or by the catalytic reforming of petroleum naphthenic fractions. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 5th ed)

A drug-metabolizing, cytochrome P-448 (P-450) enzyme which catalyzes the hydroxylation of benzopyrene to 3-hydroxybenzopyrene in the presence of reduced flavoprotein and molecular oxygen. Also acts on certain anthracene derivatives. An aspect of EC 1.14.14.1.

Chemical agents that increase the rate of genetic mutation by interfering with the function of nucleic acids. A clastogen is a specific mutagen that causes breaks in chromosomes.

A refined petroleum fraction used as a fuel as well as a solvent.

Chemical substances that are foreign to the biological system. They include naturally occurring compounds, drugs, environmental agents, carcinogens, insecticides, etc.

A body of water located at the southeastern corner of North America. It is bordered by the states to the north of Florida, Alabama, Mississippi, Louisiana, Texas; by five Mexican states to the west: Tamaulipas, Veracruz, Tabasco, Campeche, Yucatan; and by Cuba to the southeast.

Air pollutants found in the work area. They are usually produced by the specific nature of the occupation.

7,12-Dimethylbenzanthracene. Polycyclic aromatic hydrocarbon found in tobacco smoke that is a potent carcinogen.

The exposure to potentially harmful chemical, physical, or biological agents that occurs as a result of one's occupation.

Toxic, volatile, flammable liquid hydrocarbon byproduct of coal distillation. It is used as an industrial solvent in paints, varnishes, lacquer thinners, gasoline, etc. Benzene causes central nervous system damage acutely and bone marrow damage chronically and is carcinogenic. It was formerly used as parasiticide.

Gases, fumes, vapors, and odors escaping from the cylinders of a gasoline or diesel internal-combustion engine. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed & Random House Unabridged Dictionary, 2d ed)

Eight-carbon saturated hydrocarbon group of the methane series. Include isomers and derivatives.

Areas of the earth where hydrocarbon deposits of PETROLEUM and/or NATURAL GAS are located.

The presence of bacteria, viruses, and fungi in the soil. This term is not restricted to pathogenic organisms.

Adverse effect upon bodies of water (LAKES; RIVERS; seas; groundwater etc.) caused by CHEMICAL WATER POLLUTANTS.

A cytochrome P450 enzyme subtype that has specificity for relatively planar heteroaromatic small molecules, such as CAFFEINE and ACETAMINOPHEN.

Two-ring crystalline hydrocarbons isolated from coal tar. They are used as intermediates in chemical synthesis, as insect repellents, fungicides, lubricants, preservatives, and, formerly, as topical antiseptics.

Pheromones that elicit sexual attraction or mating behavior usually in members of the opposite sex in the same species.

A mass of organic or inorganic solid fragmented material, or the solid fragment itself, that comes from the weathering of rock and is carried by, suspended in, or dropped by air, water, or ice. It refers also to a mass that is accumulated by any other natural agent and that forms in layers on the earth's surface, such as sand, gravel, silt, mud, fill, or loess. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed, p1689)

A mixture of liquid hydrocarbons obtained from petroleum. It is used as laxative, lubricant, ointment base, and emollient.

Organic compounds composed exclusively of carbon and hydrogen forming a closed ring that may be either alicyclic or aromatic.

Layers of lipid molecules which are two molecules thick. Bilayer systems are frequently studied as models of biological membranes.

A natural fuel formed by partial decomposition of vegetable matter under certain environmental conditions.

The exposure to potentially harmful chemical, physical, or biological agents in the environment or to environmental factors that may include ionizing radiation, pathogenic organisms, or toxic chemicals.

A group of compounds with three aromatic rings joined in linear arrangement.

The characteristic three-dimensional shape of a molecule.

Benzopyrenes saturated in any two adjacent positions and substituted with two hydroxyl groups in any position. The majority of these compounds have carcinogenic or mutagenic activity.

A family of diphenylenemethane derivatives.

A large lobed glandular organ in the abdomen of vertebrates that is responsible for detoxification, metabolism, synthesis and storage of various substances.

An agent that causes the production of physical defects in the developing embryo.

Liquids that dissolve other substances (solutes), generally solids, without any change in chemical composition, as, water containing sugar. (Grant & Hackh's Chemical Dictionary, 5th ed)

One of the three domains of life (the others being Eukarya and ARCHAEA), also called Eubacteria. They are unicellular prokaryotic microorganisms which generally possess rigid cell walls, multiply by cell division, and exhibit three principal forms: round or coccal, rodlike or bacillary, and spiral or spirochetal. Bacteria can be classified by their response to OXYGEN: aerobic, anaerobic, or facultatively anaerobic; by the mode by which they obtain their energy: chemotrophy (via chemical reaction) or PHOTOTROPHY (via light reaction); for chemotrophs by their source of chemical energy: CHEMOLITHOTROPHY (from inorganic compounds) or chemoorganotrophy (from organic compounds); and by their source for CARBON; NITROGEN; etc.; HETEROTROPHY (from organic sources) or AUTOTROPHY (from CARBON DIOXIDE). They can also be classified by whether or not they stain (based on the structure of their CELL WALLS) with CRYSTAL VIOLET dye: gram-negative or gram-positive.

Six-carbon saturated hydrocarbon group of the methane series. Include isomers and derivatives. Various polyneuropathies are caused by hexane poisoning.

Insects of the family Formicidae, very common and widespread, probably the most successful of all the insect groups. All ants are social insects, and most colonies contain three castes, queens, males, and workers. Their habits are often very elaborate and a great many studies have been made of ant behavior. Ants produce a number of secretions that function in offense, defense, and communication. (From Borror, et al., An Introduction to the Study of Insects, 4th ed, p676)

The location of the atoms, groups or ions relative to one another in a molecule, as well as the number, type and location of covalent bonds.

Oxidases that specifically introduce DIOXYGEN-derived oxygen atoms into a variety of organic molecules.

Family of small, surface-dwelling fish that inhabit fresh and brackish waters, and coastal marine areas.

A family of DNA-binding transcription factors that contain a basic HELIX-LOOP-HELIX MOTIF.

The relationship between the chemical structure of a compound and its biological or pharmacological activity. Compounds are often classed together because they have structural characteristics in common including shape, size, stereochemical arrangement, and distribution of functional groups.

Chemical substances, excreted by an organism into the environment, that elicit behavioral or physiological responses from other organisms of the same species. Perception of these chemical signals may be olfactory or by contact.

Particles of any solid substance, generally under 30 microns in size, often noted as PM30. There is special concern with PM1 which can get down to PULMONARY ALVEOLI and induce MACROPHAGE ACTIVATION and PHAGOCYTOSIS leading to FOREIGN BODY REACTION and LUNG DISEASES.

A class of compounds composed of repeating 5-carbon units of HEMITERPENES.

Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.

Contamination of the air, bodies of water, or land with substances that are harmful to human health and the environment.

Tests of chemical substances and physical agents for mutagenic potential. They include microbial, insect, mammalian cell, and whole animal tests.

The salinated water of OCEANS AND SEAS that provides habitat for marine organisms.

Closed vesicles of fragmented endoplasmic reticulum created when liver cells or tissue are disrupted by homogenization. They may be smooth or rough.

Organic compounds that include a cyclic ether with three ring atoms in their structure. They are commonly used as precursors for POLYMERS such as EPOXY RESINS.

RNA sequences that serve as templates for protein synthesis. Bacterial mRNAs are generally primary transcripts in that they do not require post-transcriptional processing. Eukaryotic mRNA is synthesized in the nucleus and must be exported to the cytoplasm for translation. Most eukaryotic mRNAs have a sequence of polyadenylic acid at the 3' end, referred to as the poly(A) tail. The function of this tail is not known for certain, but it may play a role in the export of mature mRNA from the nucleus as well as in helping stabilize some mRNA molecules by retarding their degradation in the cytoplasm.

Substances or organisms which pollute the water or bodies of water. Use for water pollutants in general or those for which there is no specific heading.

The presence of bacteria, viruses, and fungi in water. This term is not restricted to pathogenic organisms.

A genus of gram-positive, anaerobic bacteria whose organisms divide in three perpendicular planes and occur in packets of eight or more cells. It has been isolated from soil, grains, and clinical specimens.

Reduction of pharmacologic activity or toxicity of a drug or other foreign substance by a living system, usually by enzymatic action. It includes those metabolic transformations that make the substance more soluble for faster renal excretion.

A group of methane-based halogenated hydrocarbons containing one or more fluorine and chlorine atoms.

The hard rigid covering of animals including MOLLUSCS; TURTLES; INSECTS; and crustaceans.

High temperature destruction of waste by burning with subsequent reduction to ashes or conversion to an inert mass.

Oils which evaporate readily. The volatile oils occur in aromatic plants, to which they give odor and other characteristics. Most volatile oils consist of a mixture of two or more TERPENES or of a mixture of an eleoptene (the more volatile constituent of a volatile oil) with a stearopten (the more solid constituent). The synonym essential oils refers to the essence of a plant, as its perfume or scent, and not to its indispensability.

The simplest saturated hydrocarbon. It is a colorless, flammable gas, slightly soluble in water. It is one of the chief constituents of natural gas and is formed in the decomposition of organic matter. (Grant & Hackh's Chemical Dictionary, 5th ed)

Derivatives of phosphatidic acids in which the phosphoric acid is bound in ester linkage to a choline moiety. Complete hydrolysis yields 1 mole of glycerol, phosphoric acid and choline and 2 moles of fatty acids.

Any combustible hydrocarbon deposit formed from the remains of prehistoric organisms. Examples are petroleum, coal, and natural gas.

Hydrocarbon-rich byproducts from the non-fossilized BIOMASS that are combusted to generate energy as opposed to fossilized hydrocarbon deposits (FOSSIL FUELS).

A molecule that binds to another molecule, used especially to refer to a small molecule that binds specifically to a larger molecule, e.g., an antigen binding to an antibody, a hormone or neurotransmitter binding to a receptor, or a substrate or allosteric effector binding to an enzyme. Ligands are also molecules that donate or accept a pair of electrons to form a coordinate covalent bond with the central metal atom of a coordination complex. (From Dorland, 27th ed)

The science, art, or technology dealing with processes involved in the separation of metals from their ores, the technique of making or compounding the alloys, the techniques of working or heat-treating metals, and the mining of metals. It includes industrial metallurgy as well as metallurgical techniques employed in the preparation and working of metals used in dentistry, with special reference to orthodontic and prosthodontic appliances. (From Jablonski, Dictionary of Dentistry, 1992, p494)

Five-carbon saturated hydrocarbon group of the methane series. Include isomers and derivatives.

A highly volatile inhalation anesthetic used mainly in short surgical procedures where light anesthesia with good analgesia is required. It is also used as an industrial solvent. Prolonged exposure to high concentrations of the vapor can lead to cardiotoxicity and neurological impairment.

The industry concerned with the removal of raw materials from the Earth's crust and with their conversion into refined products.

A clear, odorless, tasteless liquid that is essential for most animal and plant life and is an excellent solvent for many substances. The chemical formula is hydrogen oxide (H2O). (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)

The exposure to potentially harmful chemical, physical, or biological agents by inhaling them.

Widely distributed enzymes that carry out oxidation-reduction reactions in which one atom of the oxygen molecule is incorporated into the organic substrate; the other oxygen atom is reduced and combined with hydrogen ions to form water. They are also known as monooxygenases or hydroxylases. These reactions require two substrates as reductants for each of the two oxygen atoms. There are different classes of monooxygenases depending on the type of hydrogen-providing cosubstrate (COENZYMES) required in the mixed-function oxidation.

Compounds that contain a BENZENE ring fused to a furan ring.

A drug-metabolizing enzyme found in the hepatic, placental and intestinal microsomes that metabolizes 7-alkoxycoumarin to 7-hydroxycoumarin. The enzyme is cytochrome P-450- dependent.

Agents that modify interfacial tension of water; usually substances that have one lipophilic and one hydrophilic group in the molecule; includes soaps, detergents, emulsifiers, dispersing and wetting agents, and several groups of antiseptics.

Organic compounds that have a relatively high VAPOR PRESSURE at room temperature.

The restriction of a characteristic behavior, anatomical structure or physical system, such as immune response; metabolic response, or gene or gene variant to the members of one species. It refers to that property which differentiates one species from another but it is also used for phylogenetic levels higher or lower than the species.

Alkyl compounds containing a hydroxyl group. They are classified according to relation of the carbon atom: primary alcohols, R-CH2OH; secondary alcohols, R2-CHOH; tertiary alcohols, R3-COH. (From Grant & Hackh's Chemical Dictionary, 5th ed)

The scattering of x-rays by matter, especially crystals, with accompanying variation in intensity due to interference effects. Analysis of the crystal structure of materials is performed by passing x-rays through them and registering the diffraction image of the rays (CRYSTALLOGRAPHY, X-RAY). (From McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)

Oils which are used in industrial or commercial applications.

Waste products which threaten life, health, or the environment when improperly treated, stored, transported, disposed of, or otherwise managed.

A phase transition from liquid state to gas state, which is affected by Raoult's law. It can be accomplished by fractional distillation.

A transferase that catalyzes the addition of aliphatic, aromatic, or heterocyclic FREE RADICALS as well as EPOXIDES and arene oxides to GLUTATHIONE. Addition takes place at the SULFUR. It also catalyzes the reduction of polyol nitrate by glutathione to polyol and nitrite.

Compounds with a core of 10 carbons generally formed via the mevalonate pathway from the combination of 3,3-dimethylallyl pyrophosphate and isopentenyl pyrophosphate. They are cyclized and oxidized in a variety of ways. Due to the low molecular weight many of them exist in the form of essential oils (OILS, VOLATILE).

The relationship between the dose of an administered drug and the response of the organism to the drug.

Liquid chromatographic techniques which feature high inlet pressures, high sensitivity, and high speed.

The art or practice of preparing food. It includes the preparation of special foods for diets in various diseases.

Mixtures of many components in inexact proportions, usually natural, such as PLANT EXTRACTS; VENOMS; and MANURE. These are distinguished from DRUG COMBINATIONS which have only a few components in definite proportions.

The property of objects that determines the direction of heat flow when they are placed in direct thermal contact. The temperature is the energy of microscopic motions (vibrational and translational) of the particles of atoms.

Unctuous combustible substances that are liquid or easily liquefiable on warming, and are soluble in ether but insoluble in water. Such substances, depending on their origin, are classified as animal, mineral, or vegetable oils. Depending on their behavior on heating, they are volatile or fixed. (Dorland, 28th ed)

Exposure of the female parent, human or animal, to potentially harmful chemical, physical, or biological agents in the environment or to environmental factors that may include ionizing radiation, pathogenic organisms, or toxic chemicals that may affect offspring. It includes pre-conception maternal exposure.

Artificially produced membranes, such as semipermeable membranes used in artificial kidney dialysis (RENAL DIALYSIS), monomolecular and bimolecular membranes used as models to simulate biological CELL MEMBRANES. These membranes are also used in the process of GUIDED TISSUE REGENERATION.

Chromatography on thin layers of adsorbents rather than in columns. The adsorbent can be alumina, silica gel, silicates, charcoals, or cellulose. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)

A cell line derived from cultured tumor cells.

ACNE-like skin eruptions caused by exposure to CHLORINE-containing compounds. Exposure can be by inhalation, ingestion, or through the skin. Chloracne is often seen in people who have occupational contact with chlorinated pesticides, wood preservatives, and sealants.

Differential thermal analysis in which the sample compartment of the apparatus is a differential calorimeter, allowing an exact measure of the heat of transition independent of the specific heat, thermal conductivity, and other variables of the sample.

A deoxyribonucleotide polymer that is the primary genetic material of all cells. Eukaryotic and prokaryotic organisms normally contain DNA in a double-stranded state, yet several important biological processes transiently involve single-stranded regions. DNA, which consists of a polysugar-phosphate backbone possessing projections of purines (adenine and guanine) and pyrimidines (thymine and cytosine), forms a double helix that is held together by hydrogen bonds between these purines and pyrimidines (adenine to thymine and guanine to cytosine).

A family of insects in the order Dictyoptera (COCKROACHES), including genera Blattella, Parcoblatta, and Symploce.

The contamination of indoor air.

Enzymes that catalyze reversibly the formation of an epoxide or arene oxide from a glycol or aromatic diol, respectively.

A solventless sample preparation method, invented in 1989, that uses a fused silica fiber which is coated with a stationary phase. It is used for sample cleanup before using other analytical methods.

The relationships of groups of organisms as reflected by their genetic makeup.

The rate dynamics in chemical or physical systems.

A chemical reaction in which an electron is transferred from one molecule to another. The electron-donating molecule is the reducing agent or reductant; the electron-accepting molecule is the oxidizing agent or oxidant. Reducing and oxidizing agents function as conjugate reductant-oxidant pairs or redox pairs (Lehninger, Principles of Biochemistry, 1982, p471).

Inland bodies of standing FRESHWATER usually smaller than LAKES. They can be man-made or natural but there is no universal agreement as to their exact size. Some consider a pond to be a small body of water that is shallow enough for sunlight to reach the bottom.

Sexual activities of animals.

A genus of gram-negative, aerobic, rod-shaped bacteria widely distributed in nature. Some species are pathogenic for humans, animals, and plants.

Non-heme iron-containing enzymes that incorporate two atoms of OXYGEN into the substrate. They are important in biosynthesis of FLAVONOIDS; GIBBERELLINS; and HYOSCYAMINE; and for degradation of AROMATIC HYDROCARBONS.

A broad class of substances containing carbon and its derivatives. Many of these chemicals will frequently contain hydrogen with or without oxygen, nitrogen, sulfur, phosphorus, and other elements. They exist in either carbon chain or carbon ring form.

Acyclic branched or unbranched hydrocarbons having two carbon-carbon double bonds.

Constituent of 30S subunit prokaryotic ribosomes containing 1600 nucleotides and 21 proteins. 16S rRNA is involved in initiation of polypeptide synthesis.

A plastic substance deposited by insects or obtained from plants. Waxes are esters of various fatty acids with higher, usually monohydric alcohols. The wax of pharmacy is principally yellow wax (beeswax), the material of which honeycomb is made. It consists chiefly of cerotic acid and myricin and is used in making ointments, cerates, etc. (Dorland, 27th ed)

Residue generated from combustion of coal or petroleum.

Removal of ENVIRONMENTAL POLLUTANTS or contaminants for the general protection of the environment. This is accomplished by various chemical, biological, and bulk movement methods, in conjunction with ENVIRONMENTAL MONITORING.

Any of the processes by which nuclear, cytoplasmic, or intercellular factors influence the differential control of gene action in enzyme synthesis.

Cells propagated in vitro in special media conducive to their growth. Cultured cells are used to study developmental, morphologic, metabolic, physiologic, and genetic processes, among others.

A species of gram-negative, aerobic bacteria isolated from soil and water as well as clinical specimens. Occasionally it is an opportunistic pathogen.

The maximum exposure to a biologically active physical or chemical agent that is allowed during an 8-hour period (a workday) in a population of workers, or during a 24-hour period in the general population, which does not appear to cause appreciable harm, whether immediate or delayed for any period, in the target population. (From Lewis Dictionary of Toxicology, 1st ed)

The phenomenon whereby compounds whose molecules have the same number and kind of atoms and the same atomic arrangement, but differ in their spatial relationships. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 5th ed)

The unconsolidated mineral or organic matter on the surface of the earth that serves as a natural medium for the growth of land plants.

Naphthalene derivatives carrying one or more hydroxyl (-OH) groups at any ring position. They are often used in dyes and pigments, as antioxidants for rubber, fats, and oils, as insecticides, in pharmaceuticals, and in numerous other applications.

A genus of gram-negative, aerobic, rod-shaped bacteria characterized by an outer membrane that contains glycosphingolipids but lacks lipopolysaccharide. They have the ability to degrade a broad range of substituted aromatic compounds.

The vapor state of matter; nonelastic fluids in which the molecules are in free movement and their mean positions far apart. Gases tend to expand indefinitely, to diffuse and mix readily with other gases, to have definite relations of volume, temperature, and pressure, and to condense or liquefy at low temperatures or under sufficient pressure. (Grant & Hackh's Chemical Dictionary, 5th ed)

Any enterprise centered on the processing, assembly, production, or marketing of a line of products, services, commodities, or merchandise, in a particular field often named after its principal product. Examples include the automobile, fishing, music, publishing, insurance, and textile industries.

Elements of limited time intervals, contributing to particular results or situations.

A rigorously mathematical analysis of energy relationships (heat, work, temperature, and equilibrium). It describes systems whose states are determined by thermal parameters, such as temperature, in addition to mechanical and electromagnetic parameters. (From Hawley's Condensed Chemical Dictionary, 12th ed)

Synthetic phospholipid used in liposomes and lipid bilayers to study biological membranes. It is also a major constituent of PULMONARY SURFACTANTS.