Hydration Effects Accompanying the Substitution of Counterions in the Ionic Atmosphere of Poly(rA)·Poly(rU) and Poly(rA)·2Poly(rU) Helices

1996 ◽  
Vol 118 (30) ◽  
pp. 7033-7039 ◽  
Author(s):  
Vitaly Buckin ◽  
Huy Tran ◽  
Victor Morozov ◽  
Luis A. Marky
Keyword(s):  
Ionic Atmosphere

scholarly journals Effect of Droplet Size and Counterions on the Spatial Distribution of Ions

2019 ◽  
Author(s):  
Victor Kwan ◽  
Styliani Consta
Keyword(s):  
Spatial Distribution ◽  
Reaction Mechanisms ◽  
Charge Carriers ◽  
Transfer Reactions ◽  
Spatial Distributions ◽  
Hydronium Ions ◽  
Ionic Atmosphere ◽  
Droplet Sizes ◽  
Charge Transfer Reactions ◽  
First Time

Electrosprayed droplets have emerged as a new environment for accelerating chemical reactions by orders of magnitude relative to their bulk analogues. Nevertheless the reaction mechanisms are still unknown. Unraveling the ion spatial distribution is critical as to where charge transfer reactions are likely to take place and as to their effect on the ionic atmosphere of macroions. Here we investigate the ion spatial distributions in aqueous droplets with diameters in the range of 5 nm to 16 nm with and without counterions using molecular dynamics. The charge carriers are Na, Cl ions and model hydronium ions. For the first time droplet sizes that are accessible to experimental scrutiny are modeled atomistically. <br>

scholarly journals Fluorescence Fluctuation Spectroscopy for Probing the Ionic Atmosphere of Nucleic Acids

2009 ◽  
Vol 96 (3) ◽  
pp. 207a
Author(s):  
Alan K. Van Orden ◽  
Keir Fogarty ◽  
Jeffrey T. McPhee ◽  
Eric Scott
Keyword(s):  
Nucleic Acids ◽  
Fluorescence Fluctuation Spectroscopy ◽  
Ionic Atmosphere

Supramolecular Aggregation of Inorganic Molecules at Au(111) Electrodes under a Strong Ionic Atmosphere

2009 ◽  
Vol 131 (41) ◽  
pp. 14728-14737 ◽  
Author(s):  
Yong-Chun Fu ◽  
Yu-Zhuan Su ◽  
De-Yin Wu ◽  
Jia-Wei Yan ◽  
Zhao-Xiong Xie ◽  
...  
Keyword(s):  
Ionic Atmosphere ◽  
Inorganic Molecules ◽  
Supramolecular Aggregation

scholarly journals The cataphoresis of suspended particles. Part I.—The equation of cataphoresis

1931 ◽  
Vol 133 (821) ◽  
pp. 106-129 ◽  
Keyword(s):  
Dielectric Constant ◽  
Double Layer ◽  
Electrical Double Layer ◽  
Applied Field ◽  
Ionic Concentration ◽  
Stream Line ◽  
Radius Of Curvature ◽  
Ionic Atmosphere ◽  
Two Phases ◽  
Molecular Dimensions

§ 1. The theory of cataphoresis, and of the complementary phenomenon of electrosmosis, is based on the conception of an “ electrical double layer ” at the interface between the two phases whose relative motion is under consideration.* In the original theory, as propounded by Quincke and Helm­holtz, this electrical double layer was regarded as a kind of parallel plate condenser made up of two laminar distributions of electrification, of which one—the so-called “ inner sheet ”—was firmly attached to the rigid phase, while the other—the “ outer sheet ”—resided in the mobile phase ; the separation between the two was considered to be a distance of the order of molecular dimensions. The currently accepted view, initiated by Gouy, differs from that of Helmholtz chiefly in that the outer sheet of the double layer is con­sidered to be a diffuse distribution of electrification—an “ ionic atmosphere ” of the type investigated by Debye and his collaborators in connection with the theory of strong electrolytes. The net electric density in the ionic atmosphere varies continuously from a maximum in the immediate neighbourhood of the fixed inner sheet, to a negligibly small value in the bulk of the liquid, over a distance which is a function of the ionic concentration, and which lies as a rule between molecular dimensions and some thousand micromillimetres. In a deduction which appears to be completely consistent with this more modern view of the double layer, Smoluchowski deduced the expression U = DXζ/4π η (1) for the cataphoretic velocity U ; X is the applied field strength, ζ the potential difference across the double layer, D the dielectric constant and η the viscosity of the medium. The equation is identical with that developed by Helmholtz except for the inclusion of the dielectric constant, but was deduced on a much more general basis, and is claimed by Smoluchowski to be valid for rigid electrically insulating particles of any shape, subject only to the following four restrictions :— 1) That the usual hydrodynamical equations for the motion of a viscous fluid may be assumed to hold both in the bulk of the liquid and within the double layer; (2) That the motion is “stream line motion,” and slow enough for the “inertia terms” in the hydrodynamic equations to be neglected ; (3) That the applied field may be taken as simply superimposed on the field due to the electrical double layer ; and (4) That the thickness of the double layer ( i. e, the distance normal to the interface over which the potential differs appreciably from that in the bulk of the liquid) is small compared with the radius of curvature at any point of the surface.

scholarly journals The Ionic Atmosphere around A-RNA: Poisson-Boltzmann and Molecular Dynamics Simulations

2012 ◽  
Vol 102 (4) ◽  
pp. 829-838 ◽  
Author(s):  
Serdal Kirmizialtin ◽  
Alexander R.J. Silalahi ◽  
Ron Elber ◽  
Marcia O. Fenley
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulations ◽  
Ionic Atmosphere ◽  
Poisson Boltzmann ◽  
Dynamics Simulations

Viscosity changes in concentrated skim-milk treated with alkali, urea and calcium-complexing agents: I. The importance of the casein micelle

1959 ◽  
Vol 26 (3) ◽  
pp. 248-257 ◽  
Author(s):  
R. Beeby ◽  
K. Kumetat
Keyword(s):  
Technical Assistance ◽  
Skim Milk ◽  
Complexing Agents ◽  
Casein Micelle ◽  
Protein Chemistry ◽  
Casein Micelles ◽  
Time Curve ◽  
Staff Members ◽  
Ionic Atmosphere ◽  
Major Factors

The viscosity of concentrated skim-milk changed markedly with time upon the addition of urea, calcium-complexing agents or alkali, the viscosity-time curve passing through a distinct maximum. Also, the characteristic opacity of the milk disappeared in the presence of these reagents.These phenomena are explained in terms of a postulated expansion of the casein micelles followed by their disintegration into ‘molecular’ units.Electrostatic repulsions within the casein micelles are considered to be the cause of expansion.Calcium, either in the ionic atmosphere of the casein micelle or as calcium bridges within the micelle, and hydrogen bonds are regarded as two of the major factors responsible for maintaining the stable structure of the casein micelle.The authors wish to thank Mr E. F. Woods, Division of Protein Chemistry, C.S.I.R.O., Melbourne, and various staff members of the Dairy Research Section, C.S.I.R.O., Melbourne, for helpful discussion during the preparation of the manuscript. The technical assistance of Miss Audrey K. Morris is also gratefully acknowledged.

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