Stearic Acids: A group of compounds that are derivatives of octadecanoic acid which is one of the most abundant fatty acids found in animal lipids. (Stedman, 25th ed)Fatty Acids: Organic, monobasic acids derived from hydrocarbons by the equivalent of oxidation of a methyl group to an alcohol, aldehyde, and then acid. Fatty acids are saturated and unsaturated (FATTY ACIDS, UNSATURATED). (Grant & Hackh's Chemical Dictionary, 5th ed)Oleic Acid: An unsaturated fatty acid that is the most widely distributed and abundant fatty acid in nature. It is used commercially in the preparation of oleates and lotions, and as a pharmaceutical solvent. (Stedman, 26th ed)Palmitic Acids: A group of 16-carbon fatty acids that contain no double bonds.Palmitic Acid: A common saturated fatty acid found in fats and waxes including olive oil, palm oil, and body lipids.Hydrogenation: Addition of hydrogen to a compound, especially to an unsaturated fat or fatty acid. (From Stedman, 26th ed)Oleic Acids: A group of fatty acids that contain 18 carbon atoms and a double bond at the omega 9 carbon.Fatty Acids, Unsaturated: FATTY ACIDS in which the carbon chain contains one or more double or triple carbon-carbon bonds.Linoleic Acid: A doubly unsaturated fatty acid, occurring widely in plant glycosides. It is an essential fatty acid in mammalian nutrition and is used in the biosynthesis of prostaglandins and cell membranes. (From Stedman, 26th ed)Dietary Fats: Fats present in food, especially in animal products such as meat, meat products, butter, ghee. They are present in lower amounts in nuts, seeds, and avocados.Chromatography, Gas: 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.Membrane Fluidity: The motion of phospholipid molecules within the lipid bilayer, dependent on the classes of phospholipids present, their fatty acid composition and degree of unsaturation of the acyl chains, the cholesterol concentration, and temperature.Stearates: Salts and esters of the 18-carbon saturated, monocarboxylic acid--stearic acid.Spin Labels: Molecules which contain an atom or a group of atoms exhibiting an unpaired electron spin that can be detected by electron spin resonance spectroscopy and can be bonded to another molecule. (McGraw-Hill Dictionary of Chemical and Technical Terms, 4th ed)Phospholipids: Lipids containing one or more phosphate groups, particularly those derived from either glycerol (phosphoglycerides see GLYCEROPHOSPHOLIPIDS) or sphingosine (SPHINGOLIPIDS). They are polar lipids that are of great importance for the structure and function of cell membranes and are the most abundant of membrane lipids, although not stored in large amounts in the system.Veratrum: A plant genus of the family LILIACEAE with roots that contain VERATRUM ALKALOIDS used as emetics, parasiticides, antihypertensives. It is the main ingredient of Boicil.Linoleic Acids: Eighteen-carbon essential fatty acids that contain two double bonds.Lauric Acids: 12-Carbon saturated monocarboxylic acids.Electron Spin Resonance Spectroscopy: A technique applicable to the wide variety of substances which exhibit paramagnetism because of the magnetic moments of unpaired electrons. The spectra are useful for detection and identification, for determination of electron structure, for study of interactions between molecules, and for measurement of nuclear spins and moments. (From McGraw-Hill Encyclopedia of Science and Technology, 7th edition) Electron nuclear double resonance (ENDOR) spectroscopy is a variant of the technique which can give enhanced resolution. Electron spin resonance analysis can now be used in vivo, including imaging applications such as MAGNETIC RESONANCE IMAGING.Lipids: A generic term for fats and lipoids, the alcohol-ether-soluble constituents of protoplasm, which are insoluble in water. They comprise the fats, fatty oils, essential oils, waxes, phospholipids, glycolipids, sulfolipids, aminolipids, chromolipids (lipochromes), and fatty acids. (Grant & Hackh's Chemical Dictionary, 5th ed)Fats: The glyceryl esters of a fatty acid, or of a mixture of fatty acids. They are generally odorless, colorless, and tasteless if pure, but they may be flavored according to origin. Fats are insoluble in water, soluble in most organic solvents. They occur in animal and vegetable tissue and are generally obtained by boiling or by extraction under pressure. They are important in the diet (DIETARY FATS) as a source of energy. (Grant & Hackh's Chemical Dictionary, 5th ed)Fatty Acids, Monounsaturated: Fatty acids which are unsaturated in only one position.Chromatography, Thin Layer: 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)Sodium Azide: A cytochrome oxidase inhibitor which is a nitridizing agent and an inhibitor of terminal oxidation. (From Merck Index, 12th ed)alpha-Linolenic Acid: A fatty acid that is found in plants and involved in the formation of prostaglandins.Cacao: A tree of the family Sterculiaceae (or Byttneriaceae), usually Theobroma cacao, or its seeds, which after fermentation and roasting, yield cocoa and chocolate.Membrane Lipids: Lipids, predominantly phospholipids, cholesterol and small amounts of glycolipids found in membranes including cellular and intracellular membranes. These lipids may be arranged in bilayers in the membranes with integral proteins between the layers and peripheral proteins attached to the outside. Membrane lipids are required for active transport, several enzymatic activities and membrane formation.Plant Oils: Oils derived from plants or plant products.Stearoyl-CoA Desaturase: An enzyme that catalyzes the formation of oleoyl-CoA, A, and water from stearoyl-CoA, AH2, and oxygen where AH2 is an unspecified hydrogen donor.Cholesterol: The principal sterol of all higher animals, distributed in body tissues, especially the brain and spinal cord, and in animal fats and oils.Acylation: The addition of an organic acid radical into a molecule.Glycerides: GLYCEROL esterified with FATTY ACIDS.Fatty Acids, Nonesterified: FATTY ACIDS found in the plasma that are complexed with SERUM ALBUMIN for transport. These fatty acids are not in glycerol ester form.Linolenic Acids: Eighteen-carbon essential fatty acids that contain three double bonds.Fatty Acid Desaturases: A family of enzymes that catalyze the stereoselective, regioselective, or chemoselective syn-dehydrogenation reactions. They function by a mechanism that is linked directly to reduction of molecular OXYGEN.Phosphatidylcholines: 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.Lipid Metabolism: Physiological processes in biosynthesis (anabolism) and degradation (catabolism) of LIPIDS.TriglyceridesAbsorption: The physical or physiological processes by which substances, tissue, cells, etc. take up or take in other substances or energy.Cyclic N-Oxides: Heterocyclic compounds in which an oxygen is attached to a cyclic nitrogen.Myristic Acid: A saturated 14-carbon fatty acid occurring in most animal and vegetable fats, particularly butterfat and coconut, palm, and nutmeg oils. It is used to synthesize flavor and as an ingredient in soaps and cosmetics. (From Dorland, 28th ed)