Electrostatic potential driven

However, if ions move down the concentration gradient (from the inside to the outside of the cell) an electrostatic imbalance will be created, resulting in more positive charges outside of the cell than inside. The resulting electrostatic force will drive the positive potassium ions across the membrane from outside to inside. In thermodynamic equilibrium, the concentration driven potential is exactly balanced by the electrostatic potential, a situation illustrated in Figure 1.3. 

MMS approach has been used to calculate both solvation energies and electrostatics [1,123], Potential-driven geometric flows, which admit non-curvature-driven terms, have also been proposed for biomolecular surface construction [124], While our approaches were employed by many others [125-128] for molecular surface analysis, our curvature-controlled PDEs and the geometric flow-based MMS model proposed in 2005 [120, 121, 123, 124] are, to our knowledge, the first of their kind for biomolecular surface and electrostatics/solvation modeling. 

Donnan dialysis In Donnan dialysis, a cation-exchange membrane separates the donor and receptor solutions. Cationic metal species are transported across the membrane driven by the negative electrostatic potential (the Donnan potential) across the membrane, until equilibrium is achieved. Matching of the ionic strengths of donor and acceptor solutions is necessary. Since cationic species exchange readily compared to neutral and anionic species, it is claimed that the measurement more closely relates to the free metal ion. 

Additional sources for potential barriers in ionic systems can be driven by intrinsic ionic processes. As first described by Frenkel, the formation of a net surface charge and a compensating space charge layer relates to the energy differences required to bring various ionic species to a surface [13]. Indeed, while ionic soUds are macro-scopicaUy charge-neutral, local variations in both structure and chemistry lead to internal electrostatic potentials and electric fields. Space charge layers are formed... 

As a cautionary note, in considering electrostatically driven interactions, whether they primarily involve potentials at discrete points or over extended areas, it should be kept in mind that the electrostatic potential of the resulting complex will not show the separate positive and negative features that gave rise to the interaction [93,94]. They will have been at least partially neutralized by it. 

If an ion is driven by both a gradient of its concentration and a gradient of electrostatic potential, then its flux Jp will be the sum of the component fluxes. 

Similarly, we often try to interpret changes in the free energy in terms of contributions to the potential energy function. For instance, one might want to know whether AA is primarily driven by electrostatic or van der Waals interactions. Alternatively, one might be interested in finding out what are the contributions to AA arising from... 

Besides DNA adsorption driven by a positive potential (electrostatic adsorption) DNA was also wet-adsorbed at an open circuit on a home-made polystyrene-based carbon ink [110]. This ink was prepared by a 2 3 mixture of polystyrene and graphite particles in mesitylene, and then printed on a polyester film. DNA was wef-adsorbed over the ink at 37 °C overnight. The nature of the electrode surface (graphite particles embedded in a polystyrene... 

The second parameter influencing the movement of all solutes in free-zone electrophoresis is the electroosmotic flow. It can be described as a bulk hydraulic flow of liquid in the capillary driven by the applied electric field. It is a consequence of the surface charge of the inner capillary wall. In buffer-filled capillaries, an electrical double layer is established on the inner wall due to electrostatic forces. The double layer can be quantitatively described by the zeta-potential f, and it consists of a rigid Stern layer and a movable diffuse layer. The EOF results from the movement of the diffuse layer of electrolyte ions in the vicinity of the capillary wall under the force of the electric field applied. Because of the solvated state of the layer forming ions, their movement drags the whole bulk of solution. 

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