Anhydrides: Chemical compounds derived from acids by the elimination of a molecule of water.Acetic Anhydrides: Compounds used extensively as acetylation, oxidation and dehydrating agents and in the modification of proteins and enzymes.Phthalic Anhydrides: Phthalic acid anhydrides. Can be substituted on any carbon atom. Used extensively in industry and as a reagent in the acylation of amino- and hydroxyl groups.3-alpha-Hydroxysteroid Dehydrogenase (B-Specific): A 3-hydroxysteroid dehydrogenase which catalyzes the reversible reduction of the active androgen, DIHYDROTESTOSTERONE to 5 ALPHA-ANDROSTANE-3 ALPHA,17 BETA-DIOL. It also has activity towards other 3-alpha-hydroxysteroids and on 9-, 11- and 15- hydroxyprostaglandins. The enzyme is B-specific in reference to the orientation of reduced NAD or NADPH.Succinic Anhydrides: A subclass of anhydrides with the general structure of dihydrofurandione. They can be substituted on any carbon atom. They modify and inhibit proteins and enzymes and are used in the acylation of amino- and hydroxyl groups.Citraconic Anhydrides: Methylmaleic anhydrides.Epoxy Resins: Polymeric resins derived from OXIRANES and characterized by strength and thermosetting properties. Epoxy resins are often used as dental materials.Fluoroacetates: Derivatives of acetic acid with one or more fluorines attached. They are almost odorless, difficult to detect chemically, and very stable. The acid itself, as well as the derivatives that are broken down in the body to the acid, are highly toxic substances, behaving as convulsant poisons with a delayed action. (From Miall's Dictionary of Chemistry, 5th ed)Aconitic AcidMaleatesDiethyl Pyrocarbonate: Preservative for wines, soft drinks, and fruit juices and a gentle esterifying agent.Disaccharides: Oligosaccharides containing two monosaccharide units linked by a glycosidic bond.Trifluoroacetic Acid: A very strong halogenated derivative of acetic acid. It is used in acid catalyzed reactions, especially those where an ester is cleaved in peptide synthesis.Phthalic Acids: A group of compounds that has the general structure of a dicarboxylic acid-substituted benzene ring. The ortho-isomer is used in dye manufacture. (Dorland, 28th ed)Pyran Copolymer: Copolymer of divinyl ether and maleic anhydride that acts as an immunostimulant with antineoplastic and anti-infective properties. It is used in combination with other antineoplastic agents.Chemistry: A basic science concerned with the composition, structure, and properties of matter; and the reactions that occur between substances and the associated energy exchange.Coenzyme A-Transferases: Enzymes which transfer coenzyme A moieties from acyl- or acetyl-CoA to various carboxylic acceptors forming a thiol ester. Enzymes in this group are instrumental in ketone body metabolism and utilization of acetoacetate in mitochondria. EC 2.8.3.Chemical Phenomena: The composition, conformation, and properties of atoms and molecules, and their reaction and interaction processes.Gas Chromatography-Mass Spectrometry: A microanalytical technique combining mass spectrometry and gas chromatography for the qualitative as well as quantitative determinations of compounds.Furans: Compounds with a 5-membered ring of four carbons and an oxygen. They are aromatic heterocycles. The reduced form is tetrahydrofuran.Rutamycin: A macrolide antibiotic of the oligomycin group, obtained from Streptomyces rutgersensis. It is used in cytochemistry as a tool to inhibit various ATPases and to uncouple oxidative phosphorylation from electron transport and also clinically as an antifungal agent.NorbornanesRuminococcus: A genus of gram-positive bacteria in the family Lachnospiraceae that inhabits the RUMEN; LARGE INTESTINE; and CECUM of MAMMALS.Acylation: The addition of an organic acid radical into a molecule.Benzene DerivativesMolecular Structure: 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.Succinates: Derivatives of SUCCINIC ACID. Included under this heading are a broad variety of acid forms, salts, esters, and amides that contain a 1,4-carboxy terminated aliphatic structure.MercaptoethylaminesIndicators and Reagents: Substances used for the detection, identification, analysis, etc. of chemical, biological, or pathologic processes or conditions. Indicators are substances that change in physical appearance, e.g., color, at or approaching the endpoint of a chemical titration, e.g., on the passage between acidity and alkalinity. Reagents are substances used for the detection or determination of another substance by chemical or microscopical means, especially analysis. Types of reagents are precipitants, solvents, oxidizers, reducers, fluxes, and colorimetric reagents. (From Grant & Hackh's Chemical Dictionary, 5th ed, p301, p499)Formates: Derivatives of formic acids. Included under this heading are a broad variety of acid forms, salts, esters, and amides that are formed with a single carbon carboxy group.Maleic Anhydrides: Used in copolymerization reactions, in the Diels-Alder(diene)synthesis, in the preparation of resins, pharmaceuticals and agricultural chemicals. It is a powerful irritant and causes burns.Metals, Rare Earth: A group of elements that include SCANDIUM; YTTRIUM; and the LANTHANOID SERIES ELEMENTS. Historically, the rare earth metals got their name from the fact that they were never found in their pure elemental form, but as an oxide. In addition they were very difficult to purify. They are not truly rare and comprise about 25% of the metals in the earth's crust.Maleic Hydrazide: 1,2-Dihydro-3,6-pyridazinedione. A herbicide and plant growth regulator; also used to control suckering of tobacco. Its residue in food and tobacco is highly toxic, causing CNS disturbances and liver damage.Metals, Alkaline Earth: Metals that constitute the group 2 (formerly group IIa) of the periodic table.Fructose: A monosaccharide in sweet fruits and honey that is soluble in water, alcohol, or ether. It is used as a preservative and an intravenous infusion in parenteral feeding.Crystallization: The formation of crystalline substances from solutions or melts. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Patents as Topic: Exclusive legal rights or privileges applied to inventions, plants, etc.Crystallography, X-Ray: The study of crystal structure using X-RAY DIFFRACTION techniques. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)X-Ray Diffraction: 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)Electronic Mail: Messages between computer users via COMPUTER COMMUNICATION NETWORKS. This feature duplicates most of the features of paper mail, such as forwarding, multiple copies, and attachments of images and other file types, but with a speed advantage. The term also refers to an individual message sent in this way.Food Dispensers, Automatic: Mechanical food dispensing machines.Editorial Policies: The guidelines and policy statements set forth by the editor(s) or editorial board of a publication.Authorship: The profession of writing. Also the identity of the writer as the creator of a literary production.Periodicals as Topic: A publication issued at stated, more or less regular, intervals.Postal Service: The functions and activities carried out by the U.S. Postal Service, foreign postal services, and private postal services such as Federal Express.Internet: A loose confederation of computer communication networks around the world. The networks that make up the Internet are connected through several backbone networks. The Internet grew out of the US Government ARPAnet project and was designed to facilitate information exchange.Mutagenicity Tests: Tests of chemical substances and physical agents for mutagenic potential. They include microbial, insect, mammalian cell, and whole animal tests.Mutagens: 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.Oenanthe: A plant genus of the family APIACEAE that is sometimes called Hemlock Water Dropwort but should not be confused with HEMLOCK. It contains enanthotoxin.Salmonella typhimurium: A serotype of Salmonella enterica that is a frequent agent of Salmonella gastroenteritis in humans. It also causes PARATYPHOID FEVER.Polyesters: Polymers of organic acids and alcohols, with ester linkages--usually polyethylene terephthalate; can be cured into hard plastic, films or tapes, or fibers which can be woven into fabrics, meshes or velours.Chemistry, Analytic: The branch of chemistry dealing with detection (qualitative) and determination (quantitative) of substances. (Grant & Hackh's Chemical Dictionary, 5th ed)