Essential constituent

The fats are essential constituents of the food of animals, although conversion of carbohydrates to fats in the animal body does occur. They are partially absorbed from the gut as fats to the lymphatic system and par-... 

CfiHqNaO . M.p. 277 C. The naturally occurring substance is laevorotatory. Histidine is one of the basic amino-acids occurring in the hydrolysis products of proteins, and particularly of the basic proteins, the protamines and histones. It is an essential constituent of the food of animals. 

Phosphorus compounds are very important as fertilizers (world use 1976/77 27-3 megatonnes as P2O5) but are widely used in matches, pesticides, special glasses and china ware, alloys (sleels. phosphor bronze), and metal treating (10%), detergents (40%), electrical components (e.g. GaP), foods and drinks (15%). Phosphates are an essential constituent of living organisms. U.S. production of phosphorus 1982 372 000 tonnes. 

Nitrogen is an essential constituent of all living matter, being one of the elements present in proteins. Proteins are synthesised by... 

Phosphorus, like nitrogen, is an essential constituent of living matter where it may be partly in combination (as phosphate groups) with organic groups, for example in lecithin and egg yolk, or mainly in inorganic form, as calcium phosphate(V), in bones and teeth. 

The greatest demand for potash has been in its use for fertilizers. Potassium is an essential constituent for plant growth and is found in most soils. 

Calcium is a metallic element, fifth in abundance in the earth s crust, of which if forms more than 3%. It is an essential constituent of leaves, bones, teeth, and shells. Never found in nature uncombined, it occurs abundantly as limestone, gypsum, and fluorite. Apatite is the fluorophosphate or chlorophosphate of calcium. 

Clays are composed of extremely fine particles of clay minerals which are layer-type aluminum siUcates containing stmctural hydroxyl groups. In some clays, iron or magnesium substitutes for aluminum in the lattice, and alkahes and alkaline earths may be essential constituents in others. Clays may also contain varying amounts of nonclay minerals such as quart2 [14808-60-7] calcite [13397-26-7] feldspar [68476-25-5] and pyrite [1309-36-0]. Clay particles generally give well-defined x-ray diffraction patterns from which the mineral composition can readily be deterrnined. 

Sticky waxes are generally composed of resins and wax. A high resin content gives viscosity to the melt, a long plastic range, and a brittle fracture when cooled. No modem formulas are available, but the older recipes usually had rosin, beeswax, and gum dammar as the essential constituents. 

Chromium is an essential constituent in alloys to be used above 550°C (1,000°F). It provides a tightly adherent oxide film that materially retards the oxidation process. Sihcon is a usebil element in imparting oxidation resistance to steel. It will enhance the beneficial effects of chromium. Also, for a given level of chromium, experience has shown oxidation resistance to improve as the nickel content increases. 

Highly polymeric phosphate esters (nucleic acids) present in all cells and recognized as essential constituents of chromosomes. 

Elemental character of S pr jposed by A.-L. Lavoisier though even in 1809 experiments (presumably on impure samples) led Himiphry Davy to contend that oxygen ajid hydrogen were also essential constituents of S. 

Nitrogen fixation takes place in a wide variety of bacteria, the best known of which is rhizobium which is found in nodules on the roots of leguminous plants such as peas, beans, soya and clover. The essential constituents of this and all other nitrogen-fixing bacteria are ... 

The essential constituent of the bath is sodium tetrachromate, Na2Cr40,3, which is, however, only stable at temperatures below about 25°C. This temperature should therefore not be exceeded in the operation of the bath. Current densities of 75-150 A/dm are used. The current efficiency of the bath is high (30-35%) so that the metal is deposited at the rate of about 1 tm/min. The deposits are normally matt in appearance, but are comparatively soft and readily polished. 

Recycling of the electrolyte from used, damaged, or faulty batteries and reuse in new stacks have gained considerable attention. The electrolyte is an essential constituent from the technical and economic viewpoint, showing extraordinary stability and no ageing effects. 

Nitrogen is an odourless, colourless gas which comprises ca 79% by volume of air and is an essential constituent of all living organisms, e.g. as protein. It is made in the laboratory by gently... 

In fluoride glasses, calcium fluoride is an essential constituent, but generally cryolite, NajAlFg, is also added as a flux to lower the temperature of fusion. Aluminium orthophosphate is also generally added to the fusion mixture for various reasons. Of course, the various elements may be added in different ways. Thus, calcium orthophosphate, aluminium fluoride and sodium carbonate are often used in the preparation of fluoride glasses. 

The glass polyalkenoate cement system was not viable until Wilson and Crisp discovered the action of (+)-tartaric acid as a reaction-controlling additive (Wilson Crisp, 1975,1976,1980 Wilson, Crisp Ferner, 1976 Crisp Wilson, 1976 Crisp, Lewis Wilson, 1979). It may be regarded as an essential constituent and is invariably included in glass polyalkenoate cements as a reaction-controlling additive. 

The ZOE cement has a long history. Eugenol is the essential constituent of oil of cloves, which has been used medically since the fourth century... 

Molnar, 1942). Its use specifically to relieve toothache was recorded by Vigo in the sixteenth century and reactions with metal oxides were reported by Bonastre (1827a,b). The earliest zinc oxide chelate cements used creosote (King, 1872) and later this was mixed with oil of cloves (Chisholm, 1873). Then oil of cloves was used by itself (Flagg, 1875) and finally its essential constituent, eugenol (Wessler, 1894). 

The mobile phase in LC-MS may play several roles active carrier (to be removed prior to MS), transfer medium (for nonvolatile and/or thermally labile analytes from the liquid to the gas state), or essential constituent (analyte ionisation). As LC is often selected for the separation of involatile and thermally labile samples, ionisation methods different from those predominantly used in GC-MS are required. Only a few of the ionisation methods originally developed in MS, notably El and Cl, have found application in LC-MS, whereas other methods have been modified (e.g. FAB, PI) or remained incompatible (e.g. FD). Other ionisation methods (TSP, ESI, APCI, SSI) have even emerged in close relationship to LC-MS interfacing. With these methods, ion formation is achieved within the LC-MS interface, i.e. during the liquid- to gas-phase transition process. LC-MS ionisation processes involve either gas-phase ionisation (El), gas-phase chemical reactions (Cl, APCI) or ion evaporation (TSP, ESP, SSI). Van Baar [519] has reviewed ionisation methods (TSP, APCI, ESI and CF-FAB) in LC-MS. 

Proteins, the main constituents of the animals body, are polypeptides, biopolymers consisting of many amino acid molecules (the monomers) combined together (see Chapter 11) collagen, for example, the main component of animal skin, is a complex protein consisting of many molecules of amino acids combined together into polypeptide chains (see Fig. 71). Polysaccharides, the essential constituents of plants, also consist of many monosaccharide molecules combined together. Cellulose, the most abundant biological material on earth, which makes up most of the structural... 

The Wassermann substance17 is prepared by extracting various animal organs, particularly beef heart, with alcohol, and its lipidal nature was early recognized. Pangborn174 described the preparation of a new phospholipid termed cardiolipin from beef heart and claimed that it was the essential constituent of the Wassermann substance. On hydrolysis it gave a fatty acid and a phosphorylated polysaccharide. In a later communication17 however, the carbohydrate constituent is stated... 

Upon treatment with n-BruiNF, product 97 is converted to 98, which is a key intermediate for the synthesis of the monosaccharide 3-deoxy-D-manno-2-octulosonic acid (KDO)—an essential constituent of the outer membrane lip-op oly s accharide (LPS) of gram-negative bacteria.40... 

We know that cellulose (chief component of the cell walls of a plant), proteins essential constituents of living cells, rubber, leather and natural fibres like silk, wool, etc. are all polymers and these are known as natural polymers. 

Hydrox5rpyranonate and hydroxypyridinonate complexes have been patented for the treatment of zinc deficiency (451) and are used in zinc supplements. Maltolate and ethylmaltolate complexes of zinc, copper, and tin have been included as essential constituents in patents for formulations for oral care (96). The arylmercury(II) complexes RHgL, where R = 4-XCgH4, X — Me, OMe, NO2, and L — malt, koj, have been tested for antibacterial activity (101). 

Portland cement refers to a class of hydraulic cements in which the two essential constituents are tricalcium silicate (3Ca0-Si02) and dicalcium silicate (2Ca0-Si02) with varying amounts of alumina, tricalcium aluminate, and... 

Xylan is an essential constituent of hardwoods, softwoods, and annual plants. In enzymatic processing of lignocellulosic biomass, xylanolytic enzymes may be used either individually, in selected mixtures for specific effects on only the xylan component of the raw material, or in mixtures with cellulolytic, pectinolytic or amylolytic enzymes. 

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