Calcium divalent cation

Acidic proteins elude with F and phosphate salt solutions (0.05 to 0.15 M), but not with Cr or divalent cations. This is because F and phosphate edge out the carboxyl groups of the protein from the mineral s calcium. Divalent cations enhance the binding of acidic protein to... 

Magnesium. In the adult human, 50—70% of the magnesium is in the bones associated with calcium and phosphoms. The rest is widely distributed in the soft tissues and body duids. Most of the nonbone Mg ", like K", is located in the intracellular duid where it is the most abundant divalent cation. Magnesium ion is efftcientiy retained by the kidney when the plasma concentration of Mg fads in this respect it resembles Na". The functions of Na", K", Mg ", and Ca " are interrelated so that a deficiencv of Mg " affects the metaboHsm of the other three ions (26). Foods rich in magnesium are listed in Table 9. 

New chelating ion-exchange resins are able to selectively remove many heavy metals in the presence of high concentrations of univalent and divalent cations such as sodium and calcium. The heavy metals are held as weaMy acidic chelating complexes. The order of selectivity is Cu > Ni > Zn > Co > Cd > Fe + > Mn > Ca. This process is suitable for end-of-pipe polishing and for metal concentration and recovery. 

Factors I, II, III, V, VII, VIII, IX, X, XI, XII, and XIII, Protein C, and Protein S are synthesized in the Hver. Factor III is present in many different organs throughout the body. Factor IV is the divalent cation calcium. The concentration of calcium required for normal function of the blood coagulation system is much less than required for normal physiologic function of many organs in the body, eg, myocardium. 

In spite of the good calcium and magnesium tolerance of AOS systems, situations can arise whereby too many exchangeable hardness ions present themselves to the surfactant formulation. One way to overcome this is by blending AOS with a divalent cation-tolerant surfactant. A product which has been field-tested [87] is a blend of AOS and a disulfonated alkyldiphenyloxide (DPOS). Calcium and magnesium salts of DPOS are water-soluble and remain soluble even in solutions which are very concentrated in calcium and magnesium salts. 

The effect of the nature of the divalent cation is very pronounced as illustrated in Figure 2 on sample A30. Pectins were found to be much more sensitive to copper than to calcium. A scale of affinity towards divalent cations can be easily obtained this way [18]. This result corroborates what has been measured by pH titration upon addition of increasing amount of cations [28,29], where the order of decreasing selectivity was Pb = Cu Zn > Cd = Ni > Ca. This scale does not follow the size of the radius of the cations but is in agreement with the sequence of complex stability of Irving-Williams [30]. 

The running of parallel reactions of hydrolysis, ammonolysis and depolymerization of apple pectin in aqueous solution of ammonia (IM) at 25 C were investigated. It was examined the effects of monovalent cations (Na, K", NH4 ) and divalent cations (Ca, Mg ) when they were added as chloride salts. It was found that the relative rates of the above mentioned reactions, depend on the nature and concentration of the added salts as well. The chlorides of sodium, potassium and calcium accelerate hydrolysis and depolymerization, while magnesium chloride delays these reactions. Ammonolysis was increased in cases of ammonium chloride addition. 

The biphasic effect of divalent cations such as calcium on APTT is well recognized. Thus, whereas the addition of 0.025 M calcium chloride to citrated plasma has no effect on the APTT result, both higher and lower calcium chloride concentrations such as 0.065 or 0.004 M can artifactually elevate the APTT result (100). 

Staessen J, Sartor F, Rods H, et al. 1991. The association between blood pressure, calcium and other divalent cations A population study. Journal of Human Hypertension 5 485-494. 

Another important class of pigment are the so-called toner pigments. These are water-soluble dyes containing sulfonic acid groups which are insolubilized by forming a salt with a divalent cation such as calcium and barium5 (Scheme 2). Until recently the toner pigments were perceived merely as insoluble salts but X-ray studies have shown them to exist as supramolecular metal complexes (see Section 9.12.4.2). 

Wada, N., Yamashita, K. and Umegaki, T. (1995) Effects of divalent cations upon nucleation, growth and transformation of calcium carbonate polymorphs under conditions of double diffusion. Journal of Crystal Growth, 148, 297-304. 

Nor-bixin is damaged by sulfur dioxide if the concentration exceeds 100 ppm. Acidic conditions or divalent cations, particularly calcium, can cause nor-bixin to precipitate. These problems are tackled by producing nor-bixin preparations with buffers and sequestrants. 

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