Calcium Subject

During the meat diet period, calcium excretion of six of the nine subjects reached a maximum by day 2. Yet in three subjects calcium excretion continued to increase till day 7. From these data, one may infer that an equilibrium probably had not been established during this seven-day period. 

Experiment 159. — (a) Subject calcium chloride to the flame test. Record the result. 

Sameul, C. T Uromucoid excretion in normal subjects, calcium stone formers and in patients with chronic renal failure. Urol. Res. 7, 5-12 (1979). 

Metallic sodium. This metal is employed for the drying of ethers and of saturated and aromatic hydrocarbons. The bulk of the water should first be removed from the liquid or solution by a preliminary drying with anhydrous calcium chloride or magnesium sulphate. Sodium is most effective in the form of fine wire, which is forced directly into the liquid by means of a sodium press (see under Ether, Section II,47,i) a large surface is thus presented to the liquid. It cannot be used for any compound with which it reacts or which is affected by alkalis or is easily subject to reduction (due to the hydrogen evolved during the dehydration), viz., alcohols, acids, esters, organic halides, ketones, aldehydes, and some amines. 

Calcium Absorption. Phytates in cereal grains have also been reported to interfere with the absorption of calcium. However, a long-term study indicated a retention of calcium in subjects that consume large amounts of bread made with high extraction of flour (19). 

The second principal advantage is that CYANEX 272 is the only one of the three above-mentioned compounds that extracts cobalt in preference to calcium (52). This property can minimise or eliminate the solvent losses that are associated with calcium extraction and the subsequent precipitation of gypsum cmds in the scmbbing or stripping circuits. This is illustrated in Eigure 1 where calcium extraction is shown as a function of pH for the three subject reagents. 

In the EHE process, a starch slurry is prepared and calcium, as the chloride or hydroxide, is added as a cofactor to provide heat stabiUty to the enzyme. The starch slurry is passed through a stream injection heater and held at temperature for about one hour. The resulting 4—8 DE hydrolyzate is then subjected to a heat treatment in a hoi ding tube, redosed with enzyme, and allowed to react for one hour to a DE level of 10—15. 

Sa.tura.tion Index. Materials of constmction used in pools are subject to the corrosive effects of water, eg, iron and copper equipment can corrode whereas concrete and plaster can undergo dissolution, ie, etching. The corrosion rate of metallic surfaces has been shown to be a function of the concentrations of Cl ,, dissolved O2, alkalinity, and Ca hardness as well as buffer intensity, time, and the calcium carbonate saturation index (35). 

Food and pharmaceutical grades of calcium carbonate are covered by the Food Chemicals Codex (7) and the United States Pharmacopeia (8) and subject to U.S. Food and Dmg Administration Good Manufacturing Practices (9). Both purity requirements and test methods are available (7,8). Calcium carbonate is listed in the U.S. Code of Federal Regulation as a food additive, and is authorized for use in both paper and plastic food contact appHcations. 

Bleaching Powder. This material, known siace 1798, is made by chlorination of slightly moist hydrated lime, calcium hydroxide [1305-62-0] Ca(OH)2- It has the empirical formula Ca(OCl)2 CaCl2 Ca(OH)2 2H20. Its compositioa, loag a subject of coatroversy, was estabHshed by phase studies, microscopy, and x-ray diffraction techniques (241). The initial chlorination products are monobasic calcium chloride [14031-38-4] and dibasic calcium hypochlorite [12394-14-8] ... 

Calcium cyanamide has been used in the treatment of alcohoHcs. A small piH, taken once a day, subjects the user to cyanamide flush if any alcohol is taken. The result is unpleasant and discourages drinking (33). 

Castable Monolithic Refractories Standard portland cement is made of calcium hydroxide. In exposures above 427°C (800°F) the hydroxyl ion is removed from portland (water removed) below 427°C (800°F), water is added. This cyclic exposure results in spalling. Castables are made of calcium aluminate (rather than portland) without the hydroxide they are not subject to that cychc spaJhng failure. 

Dihydropyridines not only are intermediates for the synthesis of pyridines, but also are themselves an important class of N-heterocycles an example is the coenzyme NADH. Studies on the function of NADH led to increased interest in the synthesis of dihydropyridines as model compounds. Aryl-substituted dihy-dropyridines have been shown to be physiologically active as calcium antagonists. Some derivatives have found application in the therapy of high blood pressure and angina pectoris. For that reason the synthesis of 1,4-dihydropyridines has been the subject of intensive research and industrial use. The Hantzsch synthesis has thus become an important reaction. 

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