Temperature dependence of surface conductance and a model of vicinal (interfacial) water

Schufle, J. A.; Huang, Chin-Tsung; Drost-Hansen, W.

doi:10.1016/0021-9797(76)90300-3

Cited by 34 publications

(4 citation statements)

References 16 publications

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“…In contrast, Bek and Jakobsson (1994) calculated the Coulomb repulsion between ions in a cylindrical channel, using a dielectric constant of 20. A biological vestibule contains ϳ500 water molecules, and when such a small number of molecules are confined in a space, some of the macroscopic properties of such "vicinal water" are known to differ appreciably from those determined in bulk water (Schufle et al, 1976;Drost-Hansen and Singleton, 1992). A small decrease in the dielectric constant of a liquid leads to a similar increase in the potential profile (see Fig.…”

Section: Discussionmentioning

confidence: 99%

Analytical Solutions of Poisson's Equation for Realistic Geometrical Shapes of Membrane Ion Channels

Kuyucak

Hoyles

Chung

1998

Biophysical Journal

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Analytical solutions of Poisson's equations satisfying the Dirichlet boundary conditions for a toroidal dielectric boundary are presented. The electric potential computed anywhere in the toroidal conduit by the analytical method agrees with the value derived from an iterative numerical method. We show that three different channel geometries, namely, bicone, catenary, and toroid, give similar potential profiles as an ion traverses along their central axis. We then examine the effects of dipoles in the toroidal channel wall on the potential profile of ions passing through the channel. The presence of dipoles eliminates the barrier for one polarity of ion, while raising the barrier for ions of the opposite polarity. We also examine how a uniform electric field from an external source is affected by the protein boundary and a mobile charge. The channel distorts the field, reducing it in the vestibules, and enhancing it in the constricted segment. The presence of an ion in one vestibule effectively excludes ions of the same polarity from that vestibule, but has little effect in the other vestibule. Finally, we discuss how the solutions we provide here may be utilized to simulate a system containing a channel and many interacting ions.

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Section: Discussionmentioning

confidence: 99%

Analytical Solutions of Poisson's Equation for Realistic Geometrical Shapes of Membrane Ion Channels

Kuyucak

Hoyles

Chung

1998

Biophysical Journal

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“…Figure 3. Calculated difference spectra, that Is, the spectra of continuum for 1 M HCI, effective thickness 25.5 ± 0.5 µ absorbed in quartz pores (1), and for film of 1 M HCI, thickness 25.4 ± 0.5 µ between parallel quartz plates (2). A special holder was used in all cases to avoid evaporation.…”

Section: Methodsmentioning

confidence: 99%

Long-range structuring of water by quartz and glass surfaces as indicated by the infrared continuum and diffusion coefficient of the excess proton

Roberts¹,

Zuńdel²

1980

J. Phys. Chem.

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“…The thickness of CUPs ranges from 0.43 to 0.77 nm, which is about two to four water molecules thick. While previous studies have been suggested that surface water is as thick as from a few water molecules to several dozens of water molecules depending on the particles surface properties [ 75 , 76 ]. The thickness is likely to be primarily controlled by the charge density of the CUP particle surface and any hydrogen bonding groups at the surface.…”

Section: Resultsmentioning

confidence: 99%

Thermodynamic Characterization of Free and Surface Water of Colloidal Unimolecular Polymer (CUP) Particles Utilizing DSC

2020

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Colloidal Unimolecular Polymer (CUP) particles are spheroidal, 3–9 nm with charged groups on the surface and a hydrophobic core, which offer a larger surface water fraction to improve the analysis of its characteristics. Differential scanning calorimetry (DSC) was performed to determine the characteristics of surface water. These properties include the amount of surface water, the layer thickness, density, specific heat of the surface water above and below the freezing point of water, melting point depression of free water, effect of charge density and particle size. The charge density on the CUP surface was varied as well as the molecular weight which controls the particle diameter. The surface water is proportional to the weight fraction of CUP <20%. Analogous to recrystallization the CUP particles were trapped in the ice when rapidly cooled but slow cooling excluded the CUP, causing inter-molecular counterion condensation and less surface water. The density of surface water was calculated to be 1.023 g/mL to 1.056 g/mL depending on the surface charge density. The thickness of surface water increased with surface charge density. The specific heat of surface water was found to be 3.04 to 3.07 J/g·K at 253.15 K and 3.07 to 3.09 J/g·K at 293.15 K. The average area occupied by carboxylate and ester groups on the CUP surface were determined.

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Temperature dependence of surface conductance and a model of vicinal (interfacial) water

Cited by 34 publications

References 16 publications

Analytical Solutions of Poisson's Equation for Realistic Geometrical Shapes of Membrane Ion Channels

Analytical Solutions of Poisson's Equation for Realistic Geometrical Shapes of Membrane Ion Channels

Long-range structuring of water by quartz and glass surfaces as indicated by the infrared continuum and diffusion coefficient of the excess proton

Thermodynamic Characterization of Free and Surface Water of Colloidal Unimolecular Polymer (CUP) Particles Utilizing DSC

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