Magnesium actions/effects

The combined action of lithium in liquid ammonia and carbon dioxide upon androst-4-en-3-one led to a synthesis of the /3-keto-ester (189), after esterification of the intermediate acid the reaction is one of reductive methoxycarbonyla-tion.82 Alkylation of the keto-ester (189) afforded a separable mixture of the 4/3-methyl steroid (190) as the major product (55%) and the corresponding 4a-methyl epimer. Reduction of the steroid (190) led to 4a-hydroxymethyl-4/3-methyl-5a-androstan-3/3-ol. Finally in this section, it has been noted that vinyl-magnesium bromide effects 1,4-addition to the a(3-unsaturated ketone 17/3-hydroxy-5a-androst-l-en-3-one to yield la-vinyl-5a-androstan-3-on-17/3-ol, which could be further reduced to the la-ethyl-3-ketone.83... 

Phospha.tes, Pentasodium triphosphate [7758-29-4] sodium tripolyphosphate, STPP, Na P O Q, is the most widely used and most effective builder in heavy-duty fabric washing compositions (see also Phosphoric acid and phosphates). It is a strong sequestrant for calcium and magnesium, with a p c of ca 6, and provides exceUent suspending action for soils. Because of its high sequestration power, it also finds extensive appHcation in automatic-dishwashing detergents. Sodium tripolyphosphate forms stable hydrates and thus aids in the manufacture of crisp spray-dried laundry powders. 

Other flame retardants and/or smoke suppressants can also be used such as magnesium hydroxide, magnesium carbonate, magnesium-zinc complexes and some tin-zinc compositions. Zinc oxide is a common ingredient in many rubber base formulations used as part of the curing system. At the same time, the action of zinc oxide is similar to that of antimony trioxide, but less effective. 

It may be felt that the initiation of a stress-corrosion test involves no more than bringing the environment into contact with the specimen in which a stress is generated, but the order in which these steps are carried out may influence the results obtained, as may certain other actions at the start of the test. Thus, in outdoor exposure tests the time of the year at which the test is initiated can have a marked effect upon the time to failure as can the orientation of the specimen, i.e. according to whether the tension surface in bend specimens is horizontal upwards or downwards or at some other angle. But even in laboratory tests, the time at which the stress is applied in relation to the time at which the specimen is exposed to the environment may influence results. Figure 8.100 shows the effects of exposure for 3 h at the applied stress before the solution was introduced to the cell, upon the failure of a magnesium alloy immersed in a chromate-chloride solution. Clearly such prior creep extends the lifetime of specimens and raises the threshold stress very considerably and since other metals are known to be strain-rate sensitive in their cracking response, it is likely that the type of result apparent in Fig. 8.100 is more widely applicable. 

Manganese, D. of - continued with magnesium and zinc, (ti) 334 Mannitol 299, 581 Masking agents 12, 312 Mass action law 16 applications to electrolyte solutions, 23 Matrix effects 733, 794 Maxima in polarography 597 suppression of, 597, 611 Mean deviation 134 relative, 134 standard, 134 Measuring cylinders, 87 flasks, 81... 

The performance of aluminium hydroxide/magnesium hydroxide-filled systems can be enhanced by incorporation of zinc hydroxystannate in halogen-free rubbers giving reduced smoke and toxic gas emission, coupled with higher flame retardancy. This action will be complimentary to the water release and endothermic effects of aluminium hydroxide/magnesium hydroxide filler systems. 

Saline cathartics are composed of relatively poorly absorbed ions such as magnesium, sulfate, phosphate, and citrate, which produce their effects primarily by osmotic action to retain fluid in the GI tract. These agents may be given orally or rectally. 

Many of the adverse effects of lithium can be ascribed to the action of lithium on adenylate cyclase, the key enz)nne that links many hormones and neurotransmitters with their intracellular actions. Thus antidiuretic hormone and thyroid-stimulating-hormone-sensitive adenylate cyclases are inhibited by therapeutic concentrations of the drug, which frequently leads to enhanced diuresis, h)rpoth)n oidism and even goitre. Aldosterone synthesis is increased following chronic lithium treatment and is probably a secondary consequence of the enhanced diuresis caused by the inhibition of antidiuretic-hormone-sensitive adenylate cyclase in the kidney. There is also evidence that chronic lithium treatment causes an increase in serum parathyroid hormone levels and, with this, a rise in calcium and magnesium concentrations. A decrease in plasma phosphate and in bone mineralization can also be attributed to the effects of the drug on parathyroid activity. Whether these changes are of any clinical consequence is unclear. 

The antipyretic and analgesic actions of aspirin are believed to occur in a certain area of the brain. It is also thought by some that the salicylates exert their analgesia by their effect on water balance. Aspirin is anti-inflammatory because it inhibits the biosynthesis of chemicals called prostaglandins. The irritation of the stomach lining caused by aspirin can be alleviated with the use of mild bases such as sodium bicarbonate, aluminum glycinate, sodium citrate, aluminum hydroxide, or magnesium trisilicate (a common trademark for this type of aspirin is Bufferin ). 

In this special field, earlier work had been done in other laboratories, such as by the Schering Company, Berlin (36), and by Ipatieff (37) in connection with his work on the hydrogenation of camphor and of other organic compounds. At both places, the favorable effect of alkali oxides and earth alkali oxides on nickel, cobalt and copper has been investigated. Similarly, Paal and his coworkers (38) have used a palladium-aluminum hydroxide catalyst in 1913 for the hydrogenation of double bonds. Bedford and Erdman (39) had reported that the catalytic action of nickel oxide is enhanced by the oxides of aluminum, zirconium, titanium, calcium, lanthanum, and magnesium. 

Aluminum Hydroxide + Magnesium Carbonate (Gaviscon Extra Strength/ Liquid) [OTC] [Antacid/Aluminum Magnesium Salts] Uses Relief of heartburn, acid indigestion Action Neutralizes gastric acid Dose Adults. 15-30 mL PO pc hs Peds. 5-15 mL PO qid or PRN avoid in renal impair Caution T Mg (w/ renal insuff) [C, ] Disp Liq, chew tabs SE Constipation, D Interactions In addition to AlOH effects OF histamine blockers, hydantoins, nitrofurantoin, phenothiazines, ticlopidine, T effects OF... 

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