Calcium deposition

Other problems that can be associated with the high dust plant can include alkaH deterioration from sodium or potassium in the stack gas deposition on the bed, calcium deposition, when calcium in the flue gas reacts with sulfur trioxide, or formation and deposition of ammonium bisulfate. In addition, plugging of the air preheater as weU as contamination of flyash and EGD wastewater discharges by ammonia are avoided if the SCR system is located after the FGD (23). 

NOTE This uses a chelant cleaner for phosphate-based programs. Although the feed rate is theoretically based on meeting the chelant demand, in practice, however, much of the demand is satisfied by the existing phosphate precipitant. The bulk of the EDTA is available to strip off old calcium deposits. Cycles of concentration should be limited. Use this formulation at 300 to 400 ppm in the boiler. At 400 ppm product, 30 ppm chelant is provided. 

Calcium-binding proteins, 6, 564, 572, 596 intestinal, 6, 576 structure, 6, 573 Calcium carbonate calcium deposition as, 6, 597 Calcium complexes acetylacetone, 2, 372 amides, 2,164 amino acids, 3, 33 arsine oxides, 3, 9 biology, 6, 549 bipyridyl, 3, 13 crown ethers, 3, 39 dimethylphthalate, 3, 16 enzyme stabilization, 6, 549 hydrates, 3, 7 ionophores, 3, 66 malonic acid, 2, 444 peptides, 3, 33 phosphines, 3, 9 phthalocyanines, 2,863 porphyrins, 2, 820 proteins, 2, 770 pyridine oxide, 3,9 Schiff bases, 3, 29 urea, 3, 9... 

Calcium deposition biology, 6, 597 Calcium ions binding... 

Acetic acid is a fungicide and is used in cleaning products to remove calcium deposits left behind by hard water. 

M (calcium deposits in the NC11978 heart, coronary and Technical... 

Around 99% of calcium is contained in the bones, whereas the other 1% resides in the extracellular fluid. Of this extracellular calcium, approximately 40% is bound to albumin, and the remainder is in the ionized, physiologically active form. Normal calcium levels are maintained by three primary factors parathyroid hormone, 1,25-dihydroxyvitamin D, and calcitonin. Parathyroid hormone increases renal tubular calcium resorption and promotes bone resorption. The active form of vitamin D, 1,25-dihydroxyvitamin D, regulates absorption of calcium from the GI tract. Calcitonin serves as an inhibitory factor by suppressing osteoclast activity and stimulating calcium deposition into the bones. 

Vinegar is recommended for cleaning a variety of appliances and other items that may be stained by hard water deposits. Automatic coffee makers, steam irons, dishwashers, teapots, faucet heads, and shower heads — over time, all accumulate calcium deposits from hard water. Groundwater, that is, water that travels through soil and rocks, accumulates dissolved calcium ions as a consequence of the natural weathering of minerals that contain calcium such as limestone and calcite, shells, and coral. At the same time, carbon dioxide in the air dissolves in water to form carbonate ions that combine with calcium ions to form a white solid, calcium... 

A common form of EDTA used as a preservative is calcium disodium EDTA (CaNa2EDTA). What metals will this form of the sequestrant scavenge effectively The dissolution of the solid will yield calcium ions, sodium ions, and the EDTA anion. Any metal more effectively complexed than calcium will be readily scavenged, including all ions listed in Table 9.1 except silver (Ag+) and magnesium (Mg2+). (In the absence of the calcium counterion, as in the case of the acid form of EDTA, chelation of calcium in the body can occur. In fact, EDTA administered orally is an FDA-approved treatment for calcium deposits in the bloodstream that lead to cardiovascular disease.) Citric acid (Fig. 9.3.3) is another sequestrant of metal ions in foodstuffs. 

Aluminium toxicity is the likely cause of three human disorders arising from long-term haemodialysis vitamin D-resistant osteomalacia, iron adequate microcytic anaemia, and dialysis dementia (Martin, 1994). The first of these conditions is consistent with interference with calcium deposition into bone, and the accumulation of aluminium in the bone matrix. 

Patients with end-stage renal disease hyperphosphatemia ineffectively filter excess phosphate that enters the body in the normal diet.278 Elevated phosphate produces the bone disorder renal osteodystrophy. Skeletal deformity may occur, possibly associated with cardiovascular disease. Calcium deposits may further build up around the body and in blood vessels creating further health risks. The use of lanthanum carbonate is being promoted as an alternative to aluminum-based therapies.279,280 Systemic absorption, and cost have produced a clinical candidate, Fosrenol (AnorMED), an intriguing use of a lanthanide compound in therapy. 

One day in the spring of 1937, Dr. ter Meer and Dr. Ambros began the search for another buna site that was to take them, four years later, to Auschwitz. The prosecution contended that the "possible war" turned their feet toward the East. Only one buna plant was in the Rhine Valley, which offered everything they needed water power, calcium deposits, economy of operation. In and beside the Rhine River were water and rail transportation to take the finished rubber to its nearby destinations. 

After 12 weeks, no observable effect at 25 mg/kg diet dose- related adverse effects on liver, kidney calcium deposits, and chemistry at higher dietary levels (Knudsen etal. 1974)... 

Chronic exposure of both rats and mice resulted in tubular nephropathy in both males and females. In rats, lesions were present in 45-66% of the males when they were sacrificed at 110 weeks after receiving 212 and 423 mg/kg/day hexachloroethane for 66 weeks of a 78-week exposure period (NTP 1977 Weisburger 1977). The renal lesions were characterized by hyperchromic regenerative epithelium, necrosis, interstitial nephritis, fibrosis, focal pyelonephritis, tubular ectasis, and hyaline casts. Lesions were also present in females but had a lower incidence (18% and 59%) for the two dose groups. Two-year exposures of male rats to much lower doses (10 and 20 mg/kg/day) resulted in similar effects on the kidneys (NTP 1989). Minimal to mild nephropathy was present in females for doses of 80 and 160 mg/kg/day. Over 90% of the male and female mice exposed to 590 and 1,179 mg/kg/day hexachloroethane for 78 weeks displayed tubular nephropathy when sacrificed at 90 weeks (NTP 1977 Weisburger 1977). Regenerative tubular epithelium was visible and degeneration of the tubular epithelium occurred at the junction of the cortex and the medulla. Hyaline casts were present in the tubules, and fibrosis, calcium deposition, and inflammatory cells were noted in the kidney tissues. 

Sugimura Y, Mori T, Nitta I, Kotani E, Furusawa T, Tatsumi M, Kusakari S-I, Wada M, Morita Y. Calcium deposition in idioblasts of mulberry leaves. Ann Bot 1999 ... 

High levels of dietary zinc were associated with marked decreases in bone calcium deposition and in the apparent retention of calcium in male weanling albino rats. Marked increases in fecal calcium levels were also observed in the zinc-fed rats. Excessive dietary zinc was associated with a shifting of phosphorus excretion from the urine to the feces. This resulted in an increase in fecal phosphorus and provided an environmental condition which would increase the possibility of the formation of insoluble calcium phosphate salts and a subsequent decrease in calcium bioavailability. The adverse effect of high dietary zinc on calcium status in young rats could be alleviated and/or reversed with calcium supplements. 

Table IV shows data from another experiment in which the levels of calcium and phosphorus supplements were 0.4%, 0.8%, and 1.2%. Supplements of calcium resulted in significant Improvements in bone calcium levels of zinc-fed rats, whereas phosphorus supplements had little effect on bone calcium levels in zinc-fed rats. Increasing the calcium supplement from 0.4% to 0.8% resulted in additional increases in bone calcium deposition, and a level of 1.2% added calcium resulted in the same increase in bone calcium levels of rats fed 0.75% zinc as did the 0.8% calcium supplement. Mean bone calcium values of zinc-fed rats supplemented with either 0.4% calcium and phosphorus or 0.8% calcium and phosphorus were essentially the same as mean bone calcium values of zinc-fed rats supplemented with either 0.8% or 1.2% calcium. A combination supplement of 1.2% calcium and phosphorus was found to completely alleviate the decrease in bone calcium deposition associated with the feeding of a 0.75% level of zinc. Calcium supplements partially alleviated the decrease in bone phosphorus level associated with the feeding of the...

Baxter, J.H. (1947) Hepatic and renal injury with calcium deposits and cirrhosis produced in rats by pyridine. Am. J. Pathol., 24, 503-525... 

Fig. 5 Thin sections of a I foetus (a) and a fungal (b) hydrogenosome (H) from Neo-callimastix frontalis. Both hydrogenosomes are clearly enveloped by a double membrane (arrow in (a), arrowheads in (b)). Invaginations of the hydrogenosome membrane were occasionally observed (arrow in (a)). The black spot in (a) is a calcium deposit in the peripheral vesicle (asterisks). CW, cell wall. Bars = 100 nm. (Fig. 5a from Benchimol, unpublished Fig. 5b, from Benchimol et al. 1997)...

Fig. 8 Different views of T. foetus hydrogenosomes ( ) after field-emission scanning electron microscopy (FESEM) (a) and freeze-etching (b,c). An isolated hydrogenosome obtained from T. foetus observed by FESEM, where details of its surface can be seen, b A calcium deposit in the peripheral vesicle (asterisk) c shows that the peripheral vesicle (arrow) presents a smooth surface, distinct from the organelle body. Bars = 50 nm. (From Benchimol 2000)...

Calcium deposits are seen as electron-dense spots in the matrix of some hydrogenosomes when cells are incubated in the presence of calcium ions in the fixative (Fig. 3a) or processed cytochemically for the localization of Ca++ (Fig. 11a), such as with the pyroantimonate technique (Benchimol et al. 1982b). 

If allowed to accumulate, it can lead to blockages in pipes, washing machines, dishwashers, and shower heads. In Nature, we can see more dramatic examples of calcium deposits, such as stalactites and stalagmites. Calcium can also react with other chemicals, such as surfactants, to form insoluble salts that give rise to precipitates ( scum ) deposits. 

For nearly half a century the elastic fibre has been considered a primary site of vascular calcification326, 334 336), Calcium deposits in the arterial wall commonly take the form of phosphate salts which are intimately intermeshed with the protein of the elastic fibre327. Much effort has been directed toward identifying the mechanism for the initiation of focal calcification. It has been proposed that the initial step is ionic calcium binding to the uncharged peptide carbonyl oxygens of the elastic fibre protein328, 329. ... 

Goreau, T. F. Problems of growth and calcium deposition in reef corals. Endeavour 20, 32 (1961)... 

Goreau, T. F. The physiology of skeleton formation in corals. 1. A method for measuring the rate of calcium deposition by corals under different conditions. Biol. Bull. mar. biol. 

The amount of calcium deposited tit bone at any moment may be determined from experiments with radioactive calcium. In grow ing individuals, it exceeds the amount removed by bone destruction. In adults, it is about the same as the amount removed. Such individuals arc considered to be in "zero" calcium balance. In older persons. Ihe amount deposited is less than the amount removed. 

In 1918, Mellanby produced experimental rickets in dogs. In 1919, Huldschinsky ameliorated rachitic symptoms in children with ultraviolet radiation. Hess, in 1922, showed that liver oils contain the same antirachitic factor as sunlight In that same year, McCollum increased calcium deposition in rachitic rats with cod liver oil factor. In 1924. Steenbook and Hess demonstrated irradiated foods have antirachitic properties, It was in 1925 that McCollum named antirachitic factor as vitamin D. In 1931, Angus isolated crystalline vitamin D (calciferol). In 1936, Windaus isolated vitamin D3 (activated 7-dehydrocholesterol). 

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