Exchangers sodium-calcium

Glutamate aspartate exchange Acyl-carnitine exchange Calcium/sodium exchange Calcium... 

Gheyi, H. R., and Van Bladel, R., "Calcium-Sodium Exchange in Some Calcareous Soils and a Montmorillonite Clay as Compared with Predictions Based on a Double Layer Theory," Geoderma, (1976), 16, 159. 

However, for heterovalent ion exchange, the separation factor is not equivalent to the selectivity coefficient. If we consider the case of calcium-sodium exchange. 

Calcium antagonists (e.g., verapamil, nimodipine) can also block dopamine, 5-HT, and endorphin activity, alter sodium activity via a sodium-calcium counter-exchange, and act as anticonvulsants. Any or all of these actions could be involved in their putative antimanic effects ( 35). 

Topical application of an ionic polymer forms a diffusion electric double layer on the surface of the skin. We evaluated the effects of topical application of ionic polymers on the recovery rate of the skin barrier after injury. Application of a nonionic polymer did not affect the barrier recovery. Application of sodium salts of anionic polymers accelerated the barrier recovery, while that of cationic polymers delayed it. Topical application of a sodium-exchange resin accelerated the barrier recovery, but application of a calcium-exchange resin had no effect, even when the resins had the same structure. Application of a chloride-exchange resin delayed barrier recovery. Thus, topical application of ionic polymers markedly influenced skin barrier homeostasis (Figure 15.2). 

Fig. 5.1. Exchange isotherms corresponding to the reactions in Eq. 5.8 for the (silt + clay) fraction of a Vertisol, with data at pH 6 and 7 combined [data from P. F. Fletcher, G. Sposito, and C. S. LeVesque, Sodium-calcium-magnesium exchange reactions on a montmorillonitic soil I. Binary exchange reactions, Soil ScL Soc. Am. J. 48 1016 (1984)].

Sposito, G. and C. S. LeVesque. 1985. Sodium-calcium-magnesium exchange on Silver Hill illite. Soil Sci. Soc. Am. S. 49 1153-1159. 

Van Bladel, R. and H. R. Gheyi. 1980. Thermodynamic study of calcium-sodium and calcium-magnesium exchange in clacareous soils. Soil Sci. Soc. Am. J. 44 938-942. 

Consider as an example the sodium-calcium (NC) exchanger, which exchanges 3 Na+ ions for 1 Ca2+ across the cell membrane. The exchanger typically operates with calcium moving out of the cell and sodium ion moving in, as illustrated in Figure 7.5. The overall reaction for the NC exchanger is ... 

The most important industrial example of cation exchange is the preparation of sodium-montmorillonite/bentonite from calcium bentonite. As seen in Table 2.2, calcium ions have greater affinity to the layer charge than sodium ions, so the calcium-sodium cation exchange must be performed in the presence of carbonate ions. It means that calcium-montmorillonite/bentonite is suspended in sodium carbonate solution. Calcium ions precipitate with carbonate ions, so sodium ions can occupy the interlayer space. This process is known as soda activation of bentonite. The disadvantage of soda activation is that sodium-montmorillonite is contaminated with calcium carbonate. 

Regeneration of Amberlite-200 Resin. The Amberlite-200 resin was operated in the sodium form during the exchange cycle strontium and calcium ions replace sodium ions. In the regeneration cycle, high concentrations of sodium ion must be used to displace the strontium and calcium. Sodium nitrate was used to regenerate laboratory columns... 

Q Because sodium Is more reactive than calcium, sodium and calcium Ions exchange places. 

Abnormal G protein functioning dysregulates adenylate cyclase activity, phosphoinositide responses, sodium/potassium/calcium channel exchange, and activity of phospholipases. Abnormal cyclic adenosine monophosphate and phosphoinositide secondary messenger system activity. 

Two cation exchanged series of hydrated Y zeolites, ammonium/sodium and calcium/sodium, have been studied by sodium-23 MASNMR methods. The differences in chemical shift of the lines were correlated with the cation locations in Y zeolite using previously published XRD and IR data. As a result, the simulations and various intensity plots discussed in this report provide an analysis of the distribution of the sodium cations among the various Y zeolite cages, and a method of monitoring how these distributions change as a result of zeolite hydration and other treatments. The results presented here strongly indicate that sodium-23 MASNMR can be used as an analytical tool... 

I believe you stated that when you sodium-exchanged heulandite, it showed the same thermal behavior as the normal mineral and when you calcium-exchanged clinoptilolite, it did not show a heulandite-heulandite B transformation but merely a somewhat lower stability than normal clinoptilolite. Is this correct ... 

Green maple cross sections (0.03 inch) were treated with aqueous NaOH at two concentrations for five minutes. The specimens were then lightly blotted, dried (total time out of solution was about one hour), ashed, and assayed for equivalent NaOH (Table I). The amount held by the xylan carboxyl groups (computed from calcium ion exchange value), of course, is independent of the external concentration. The amount held as sodium acetate should also be independent of the external concentration. The amount held in the lumen should be proportional to the external concentration provided equilibrium was established in five minutes of immersion in the aqueous NaOH. The sum of these component amounts should be the total equivalent NaOH in the treated wood provided none of the sodium acetate diffused out of the cross section during the five minutes. 

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