scholarly journals Effects of quantum vacuum fluctuations of the electric field on DNA condensation

Open Physics ◽  
2011 ◽  
Vol 9 (1) ◽  
Author(s):  
Alfredo Iorio ◽  
Samik Sen ◽  
Siddhartha Sen
Keyword(s):  
Electric Field ◽  
Casimir Energy ◽  
Quantum Vacuum ◽  
Many Body ◽  
Classical Level ◽  
Counter Ions ◽  
Starting Point ◽  
Dna Strands ◽  
Poisson Boltzmann ◽  
Poisson Boltzmann Equation

AbstractBy assuming that not only counter-ions but DNA molecules as well are thermally distributed according to a Boltzmann law, we propose a modified Poisson-Boltzmann equation, at the classical level, as a starting point to compute the effects of quantum fluctuations of the electric field on the interaction among DNA-cation complexes. The latter are modeled here as infinite one-dimensional wires (δ-functions). Our goal is to single out such quantum-vacuum-driven interaction from the counterion-induced and water-related interactions. We obtain a universal, frustration-free Casimir-like (codimension 2) interaction that extensive numerical analysis show to be a good candidate to explain the formation and stability of DNA aggregates. Such Casimir energy is computed for a variety of configurations of up to 19 DNA strands in a hexagonal array. It is found to be many-body.

Exact solution of an electro-osmotic flow problem in a cylindrical channel of polymer electrolyte membranes

2009 ◽  
Vol 465 (2109) ◽  
pp. 2663-2679 ◽  
Author(s):  
Peter Berg ◽  
Kehinde Ladipo
Keyword(s):  
Polymer Electrolyte ◽  
Cylindrical Channel ◽  
Polymer Electrolyte Membranes ◽  
Osmotic Flow ◽  
Counter Ions ◽  
Electrolyte Membranes ◽  
Poisson Boltzmann ◽  
Poisson Boltzmann Equation ◽  
Analytical Expressions ◽  
Electro Osmotic Flow

The electric potential of counter-ions (protons) in an infinite cylindrical channel is presented as a solution of the Poisson–Boltzmann equation, involving a constant ion charge density along the wall. The distribution of protons is derived and used subsequently to compute the velocity profile and mass flow rate of the corresponding electro-osmotic flow, driven by an electric field. Analytical expressions are derived for all quantities, including the conductivity and water drag coefficient. This analysis relates especially to cylindrical nano-channels of polymer electrolyte membranes such as Nafion and addresses the validity of continuum models for these materials.

Elastic Properties of Charge Stabilized Colloidal Crystals with Simple Cubic Lattice

2016 ◽  
Vol 845 ◽  
pp. 178-181
Author(s):  
Pavel Dyshlovenko ◽  
Anastasia Batanova ◽  
Elena Gladkova ◽  
Alexey Nagatkin ◽  
Azat Nizametdinov
Keyword(s):  
Colloidal Crystals ◽  
Lattice Parameter ◽  
Colloidal Systems ◽  
Many Body ◽  
Equilibrium Pressure ◽  
Effective Interactions ◽  
Poisson Boltzmann ◽  
Poisson Boltzmann Equation ◽  
Linear Differential ◽  
The Many

Elasticity of charge stabilized colloidal crystals is studied numerically within the approximation of static lattice. Description of the colloidal systems is based on the non-linear differential Poisson-Boltzmann equation. Corresponding boundary value problems are solved numerically by finite element method. The equilibrium pressure and elastic moduli are obtained for different values of the lattice parameter. The many-body effective interactions are briefly discussed.

scholarly journals Low Density Interior in Supercooled Aqueous Nanodroplets Expels Ions to the Subsurface

2021 ◽  
Author(s):  
Shahrazad Moh'd Malek ◽  
Ivan Saika-Voivod ◽  
Styliani Consta
Keyword(s):  
Atmospheric Aerosols ◽  
Room Temperature ◽  
Chemical Reactivity ◽  
Center Of Mass ◽  
Bulk Solution ◽  
Electrostatic Model ◽  
Starting Point ◽  
Poisson Boltzmann ◽  
Poisson Boltzmann Equation ◽  
Coordinated Water

The interaction between water and ions within droplets plays a key role in the chemical reactivity of atmospheric and man-made aerosols. Here we report direct computational evidence that in supercooled aqueous nanodroplets <br>a lower density core of tetrahedrally coordinated water expels the Na+ ions to a denser and more disordered subsurface. In contrast, at room temperature, the radial distribution of a single Na+ ion in the droplet core <br>is nearly uniform. We analyze the spatial distribution of a single ion in terms of a new reference electrostatic model that we present here. The energy of the system in the analytical model is expressed as the sum of the electrostatic and surface energy of a deformable droplet. The model predicts that the ion is subject to a harmonic potential centered at the droplet's center of mass. We name this effect ``electrostatic confinement''.<br>The model's predictions are consistent with the simulation findings for a single Na+ ion at room temperature but not at supercooling. Because of the droplet's core organization at supercooling the distribution of multiple ions cannot be explained by the non-linear Poisson-Boltzmann equation.<br>Our study provides insight into the chemistry of atmospheric aerosols. We anticipate it to be the starting point for investigating the structure of supercooled electrosprayed droplets that are used to preserve the conformations of macromolecules originating from the bulk solution.<br>

Effects of Hydrodynamic Slip on Rotating Magneto-Electro-Osmotic Flow through a Periodic Microfluidic System

2021 ◽  
Vol 409 ◽  
pp. 67-89
Author(s):  
Mohammed Abdulhameed ◽  
Dauda Gulibur Yakubu ◽  
Garba Tahiru Adamu
Keyword(s):  
Boltzmann Equation ◽  
Electric Field ◽  
Laplace Transform ◽  
Electroosmotic Flow ◽  
Numerical Procedure ◽  
Flow Profile ◽  
Micro Channel ◽  
The Laplace Transform ◽  
Poisson Boltzmann ◽  
Poisson Boltzmann Equation

The study is concerned with the effects of slip velocity on a non-uniform rotating electroosmotic flow in a micro-channel. Electroosmotic driven fluid flow is obtained by the application of a potential electric field which describes the nonlinear Poisson-Boltzmann equation. The external electric potential is applied along the x and y directions which provides the necessary driving force for the electroosmotic flow. Two semi analytical techniques were employed to obtain the solution of the nonlinear Poisson-Boltzmann equation. The first method incorporates the complex normalized function into the Laplace transform and the second method is the combination of the Laplace transform and D’Alembert technique. Further, the complex normalized function became difficult to invert in closed form, hence we resort to the use of numerical procedure based on the Stehfest's algorithm. The graphical solutions to the axial velocities on both x and y components have been obtained and analyzed for the effects of the slip parameter and the amplitude of oscillation of the micro-channel walls. The solutions show that the rotating electroosmotic flow profile and the flow rate greatly depend on time, rotating parameter and the electrokinetic width. The results also indicate that the applied electric field and the electroosmotic force, play vital role on the velocity distribution in the micro-channel. The fact is that the solutions obtained in this study synthesize most of the solutions available in the previous studies. Finally, this study will be relevant in biological applications particularly in pumping mechanism to help transport substances within different parts of the systems.

Effects of Externally Applied Electric Field on the Electric Double Layer Formed in an Electrolyte Layer and its Contribution Towards Joule Heating

2011 ◽  
Author(s):  
Neeraj Sharma ◽  
Gerardo Diaz ◽  
Edbertho Leal-Quiros
Keyword(s):  
Electric Field ◽  
Double Layer ◽  
Joule Heating ◽  
Electric Potential ◽  
Applied Electric Field ◽  
Electric Double Layer ◽  
Potential Distribution ◽  
Electrolyte Layer ◽  
Poisson Boltzmann ◽  
Poisson Boltzmann Equation

Joule heating of liquid films in the presence of an externally applied electric field is influenced by the formation of the electric double layer. The thickness and charge distribution inside the electric double layer determine the extent of interaction of the charge in the electric double layer with the externally applied electric field and the Joule heating of the electrolyte layer. For this reason, the effects of externally applied electric field (both parallel and along the normal to the surface) on the electric double layer are being studied in the present paper. In the absence of the externally applied electric field, the distribution of the electric potential in the double layer is given by Poisson equation. Assuming Boltzmann distribution for the ionic concentration in the double layer, one arrives at Poisson-Boltzmann equation for the electric potential distribution. The externally applied electric field changes this electric potential distribution. Hence, the contribution of the externally applied electric field is studied by including it in the Poisson-Boltzmann equation.

Examining sharp restart in a Monte Carlo method for the linearized Poisson–Boltzmann equation

2020 ◽  
Vol 26 (3) ◽  
pp. 223-244
Author(s):  
W. John Thrasher ◽  
Michael Mascagni
Keyword(s):  
Monte Carlo ◽  
Free Energy ◽  
Monte Carlo Algorithm ◽  
Significant Bias ◽  
Poisson Boltzmann ◽  
Electrostatic Free Energy ◽  
Poisson Boltzmann Equation ◽  
The Stability ◽  
Potential Methods ◽  
The Individual

AbstractIt has been shown that when using a Monte Carlo algorithm to estimate the electrostatic free energy of a biomolecule in a solution, individual random walks can become entrapped in the geometry. We examine a proposed solution, using a sharp restart during the Walk-on-Subdomains step, in more detail. We show that the point at which this solution introduces significant bias is related to properties intrinsic to the molecule being examined. We also examine two potential methods of generating a sharp restart point and show that they both cause no significant bias in the examined molecules and increase the stability of the run times of the individual walks.

scholarly journals Monte Carlo methods for linear and non-linear Poisson-Boltzmann equation

2015 ◽  
Vol 48 ◽  
pp. 420-446 ◽  
Author(s):  
Mireille Bossy ◽  
Nicolas Champagnat ◽  
Hélène Leman ◽  
Sylvain Maire ◽  
Laurent Violeau ◽  
...  
Keyword(s):  
Monte Carlo ◽  
Boltzmann Equation ◽  
Monte Carlo Methods ◽  
Non Linear ◽  
Poisson Boltzmann ◽  
Poisson Boltzmann Equation
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