Surface anionic sites

An Improved Theory of Cellular Resting Potential Incorporating Cooperative Interaction among Surface Anionic Sites... 

Equation (3) was derived on the assumption that the surface anionic sites show no cooperative interaction. In 1979 I published a short article describing a new equation for the cellular resting potential/ incorporating the concept of site-to-site cooperative interaction of the cell surface sites as we have argued for and provided experimental evidence in support for the bulk phase (adsorbed)... 

We have been able to verify Eq. (7) in different ways (see Ling ). The cause of electrical potential measured across the inner membrane of liver mitochondria by Maloff, Scordillis, Reynolds, and Tedeschi may be cited. Here behaves almost like most excitable cells. Maloff et al. measured but found no effect whatsoever of valinomycin on K" conductance in the presence of varying [K ]e,. The present theory showed that valinomycin increases the K affinity on the surface anionic sites of the mitochondrial inner membrane, by a factor of 3. With this assumption the entire sets of their data can be qualitatively explained by Eq. (7). 

Vacant surface anionic sites, due to desorption and outward migration of a minute quantity of countercation, K from the cell surface, leaves excess of negative charge at the cell surface, giving rise to the normal resting potential. 

The rank order of selectivity exhibited by the surface anionic sites... 

Both indicate surface anionic sites of fairly low c value. During the action potential the rank order of ion selectivity of the surface anionic site becomes Li =Na >K >Rb >Cs (Hille O- Hille s finding thus not only confirms the adsorption-desorption nature of (part of) the inward Na movement it also confirms that the anionic sites have a higher c value, a fact further confirmed by the generally higher pK value of these anionic sites measured than those measured at rest (at rest, 4.6 during activation, 4.8-6.5. ... 

These, then, cire the set of possible defects for the Plane Net, and the following summarizes the types of intrinsic defects expected. Note that we have used the labelling V = vacancy i = interstitial M = cation site X = anion site and s = surface site. We have already stated that surface sites are special. Hence, they are included in our listing of intrinsic defects. 

When the DMAEMA content of NVP - DMAEMA copolymers was reduced from 20% to 8%, the silica fines stabilization effectiveness appeared to improve slightly. When the 80/20 NVP - DMAEMA copolymer was converted to a terpolymer containing 8% DMAEMA (CH SO, silica fines stabilization was substantially unaffected. However, stabilization of silica/kaolinite fines was greatly improved. This suggested that the interaction of polymer quaternary nitrogen atoms with anionic sites on mineral surfaces was important for the stabilization of migrating clays but a different interaction was important for the stabilization of silica fines. Calcite fines stabilization improved while hematite fines stabilization effectiveness decreased. This also indicated the nature of the adsorbed polymer - fine particle complex varied for different minerals. 

Schmidley JW, Wissig SL. Anionic sites on the luminal surface of fenestrated and continuous capillaries of the CNS. Brain Res 1986 363 265-271. 

Pd (15), and Au (15). Once again, STM s unique contribution in these applications arises from the small areas (ca. 2-4 A ) that are involved in the measurement process. These capabilities have enabled the mapping of the spatial distribution of electronic states. For example, cation and anion sites on GaAs surfaces have been discriminated (Stroscio, J.A. Feenstra, R.M. Newns, D.M. ... 

Simple Models. The surface chemical properties of clay minerals may often be interpreted in terms of the surface chemistry of the structural components, that is, sheets of tetrahedral silica, octahedral aluminum oxide (gibbsite) or magnesium hydroxide (brucite). In the discrete site model, the cation exchange framework, held together by lattice or interlayer attraction forces, exposes fixed charges as anionic sites. 

The (3-oxygens in the surface lattice of two series of perovskites can only be desorbed at high temperature (T>700 °C) leading to the B-site ion reduction and, surface anion vacancy generation. 

To prevent such anionic effects, so-called anionic sites are conventionally used as additives for ISE membranes. In fact, upon addition of 84, the SHG response of membrane 80 to KSCN was improved (data not shown). This result suggests that the lipophilic anion assists the surface orientation of the 80-K complexes by inhibiting the uptake of SCN" from the adjacent aqueous solution. 

The sorption of the anionic Tc (as TcOi " in an aerated system) and I (as I") is low, both on granite and bentonite, which is expected since the active surfaces and sites of the sorbents would be negatively charged. 

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