Calcium concentration factor

Methyl parathion is only slightly soluble in pH 7 water (55-60 ppm). This affects its mobility in water and its ability to be leached or solubilized into the water phase of a soil-water system. Factors most likely to affect the adsorption of methyl parathion in soil are organic matter content and cation exchange capacity. In soils of low organic matter (e.g., subsurface soils), calcium concentration, which affects the hardness of the water, may also be important (Reddy and Gambrell 1987). Several studies have shown... 

The control of the processes of phosphohpid translocation and scrambling by cytoplasmic calcium concentration is known to be one factor in regulating the appearance of phosphatidylserine on the cell surface. There is now evidence that other factors are involved in modulating membrane phospholipid distribution and for preserving phospholipid homeostasis. Current research is directed to clarify the role of these agents and to establish any connections with the initiation of apoptosis. 

In this experiment, tap water with added phosphate was used as influent. Concentration of phosphate was adjusted to an adequate range from 2 to 23 mg/jg. Calcium chloride and sodium hydroxide solution were added to maintain calcium concentration from 70 to 100 mg/jg and pH of the effluent from 9.0 to 9.5. Using this equipment, we performed experiments to obtain efficiency of phosphate removal, relationship between phosphate concentration, and crystallization rate and factors affecting phoshate removal. 

Plasma calcium concentration is the principal factor regulating PTH synthesis and release. The increase in PTH synthesis and secretion induced by hypocalcemia is believed to be mediated through activation of parathyroid gland adenylyl cyclase and a subsequent increase in intracellular cyclic adenosine monophosphate (cAMP). 

The refined source profiles that best reproduced the coarse fraction are listed in table 7. The calculated profiles of the two crustal components follow those of Mason ( ), though the calcium concentration of 20 in the limestone factor is less than the reported value. The paint pigment profile strongly resembles that calculated for the fine-fraction data. The only major difference is that unlike the fine fraction, the coarse-fraction profile does not associate barium with the paint-pigment factor. The calculated sulfur concentration in the coarse-fraction sulfate factor is much less than that in the fine-fraction and there are sizable concentrations of elements such as aluminum, iron, and lead not found in the fine-fraction profile. The origin of this factor is not clear although as described earlier a possible explanation is that a small part of the sulfate particles in the fine fraction ended up in the coarse samples. 

Another cardiac disease often associated with cardiac arrhythmias is heart failure. Many factors including high catecholamine levels, dilated tissue geometry, changes in the [3-adrenoceptor population, impairment of the regulation of the intracellular (diastolic) calcium concentration, possibly enhanced endo-thelin levels and many more contribute to altered cardiac function and make the heart more prone to arrhythmia. However, the question was whether, in addition to the well-known structural changes, gap junction alterations may also partially form the arrhythmogenic substrate. Thus, researchers were interested in whether in the course of heart failure gap junctional alterations may occur. 

Figure 10.9 Principal factors that affect the strength of renneted milk gels (curd tension) pH ( ), calcium concentration (O), protein concentration ( ), preheat treatment (x).

Alkaline earths Distribution coefficients for Sr(II) and Ba(II) as a function of concentration of Ca(II) are summarized in Figures 13a and 13b. The loadings in the case of Sr(It) (Figure 2) are in the linear isotherm range or only slightly out of it. Slopes of log D vs log calcium concentration are close to the ideal value, -1. Invariance of between 0.01 M and 0.1 M acetate buffer indicates that there is no interference from acetate complexing. At the same Ca(II) concentration, is a factor of... 

Another significant factor shown in Fig. 2 is that of the absence of calcium on the as-coated surface after extraction with warm water. In comparison, the angle-independent calcium concentration for the as-coated slide (Table 2) suggests that... 

The formation of tricalcium phosphate in a cooling system is primarily a net result of system pH, calcium concentration, temperature, and phosphate concentration factors. An increase in any of these factors leads to an increased risk of phosphate deposition. 

Ten patients who had taken lithium for less than 1 year and 13 who had taken it for more than 3 years were assessed for alterations in bone metabolism and parathyroid function (654). There were no differences in bone mineral density, serum calcium concentration, or PTH concentration, but both groups had increased bone turnover and the longterm group had nonsignificantly higher calcium and PTH concentrations (including one hyperparathyroid patient who had an adenoma excised). The authors conclusion that lithium therapy is not a risk factor for osteoporosis needs to be tempered by the small sample size, the case of adenoma, and the blood concentration trends. 

Hormone synthesis and release can be initiated by both extrinsic and intrinsic factors.2 Extrinsic factors include various environmental stimuli such as pain, temperature, light, and smell. Intrinsic stimuli include various humoral and neural factors. For instance, release of a hormone can be initiated by other hormones. These occurrences are particularly typical of the anterior pituitary hormones, which are controlled by releasing hormones from the hypothalamus. Hormonal release can be influenced by neural input a primary example is the sympathetic neural control of epinephrine and norepinephrine release from the adrenal medulla. Other intrinsic factors that affect hormone release are the levels of ions and metabolites within the body. For instance, parathyroid hormone release is governed directly by the calcium concentration in the bloodstream, and the release of... 

In addition to glutamate, various growth factors and amyloid have also been shown to destabilize the intracellular calcium concentration and to induce neurofibrillary-like degeneration in cultured brain cells. An attractive feature of the calcium hypothesis of Alzheimer s disease is that it helps to explain the heterogeneity of the disorder. In addition to functional abnormalities in excitatory amino adds, growth factors, amyloid protein,... 

Calcium performs a variety of cellular functions in muscle and nerve that ultimately result in muscular contraction. Excellent descriptions of calcium s function in muscle and nerve are to be found in the reviews by Hoyle (37), Cohen (38), and Robertson (39). At the neuromuscular junction, the excitable cells are very sensitive to changes in extracellular concentrations of calcium. Curtis (40) and Luttgau (41) described a fall in the resting action potential and electrical resistance when the extracellular calcium concentration fell below 10 M. The action potential and electrical resistance returned to normal following addition of calcium to this vitro preparation. The magnitude of the Initial muscle membrane action potential, that which regulates the propagation of further muscle contraction, is also mediated by the extracellular calcium concentration. While the inward flow of sodium ions from the extracellular space remains the dominant factor in the mechanism of muscle membrane depolarization, calcium ion flux appears to mediate the cell s permeability to sodium ions. This effect is particularly true in cardiac tissue (W). 

There are two types of calpains, /tr-calpain and m-calpain, which require an in vitro calcium concentration at pM and mM level, respectively. This calcium-binding affinity is too low to bind calcium at cytoplasmic calcium concentration. However, an in vivo target molecule or other factors that enhance the calcium binding of calpains have not been identified. It is interesting to note that m-calpain is able to function at calcium concentrations less than 10 pM in the presence of excess high concentration of isovalerylcamitine (a ratio of 20 000 mol isovalerylcamitine to 1 mol calpain). ... 

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