arXiv subjects

Wannapong Triampo

Publications and source records attributed to Wannapong Triampo.

9 recordsLinked to original sources

arXiv2004

Explicit Calculations on Small Non-Equilibrium Driven Lattice Gas Models

We have investigated the non-equilibrium nature of a lattice gas system consisting of a regular lattice of charged particles driven by an external electric field. For a big system, an exact solution cannot be obtained using a master equation approach since the many-particle system has too many degrees of freedom to allow for exact solutions. We have instead chosen to study small systems as a first step. The small systems will be composed of between two and four particles having two or three possible values of some parameters. Applying periodic boundary conditions and a hard-core or an exclusion-volume constraint and imposing conservation of particle numbers via Kawasaki-type dynamics (particle-hole exchange), we are able to calculate the exact solutions of the steady-state relative probability density function, ri, associated with each configuration of the small system.

cond-mat.stat-mech↗

arXiv2004

Modeling of the dynamic pole-to-pole oscillations of the min proteins in bacterial cell division: The effect of an external field

One of the most important steps in the developmental process of the bacteria cell at the cellular level is the determination of the middle of the cell and the proper placement of the septum, these being essential to the division of the cell. In E. coli, this step depends on the proteins MinC, MinD, and MinE. Exposure to a constant electric field may cause the bacteria cell division mechanism to change, resulting in an abnormal cytokinesis. To see the effects of an external field e.g., an electric or magnetic field on this process, we have solved a set of deterministic reaction diffusion equations, which incorporate the influence of an electric field. We have found some changes in the dynamics of the oscillations of the min proteins from pole to pole. The numerical results show some interesting effects, which are qualitatively in good agreement with some experimental results.

physics.bio-ph↗

arXiv2004

Effects of Static Magnetic Field on Growth of Leptospire, Leptospira interrogans serovar canicola: Immunoreactivity and Cell Division

The effects of the exposure of the bacterium, Leptospira interrogans serovar canicola to a constant magnetic field with magnetic flux density from a permanent ferrite magnet = 140 mT were studied. Changes in Leptospira cells after their exposure to the field were determined on the basis of changes in their growth behavior and agglutination immunoreactivity with a homologous antiserum using darkfield microscopy together with visual imaging. The data showed that the exposed Leptospira cells have lower densities and lower agglutination immunoreactivity than the unexposed control group. Interestingly, some of the exposed Leptospira cells showed abnormal morphologies such as large lengths. We discussed some of the possible reasons for these observations.

physics.bio-ph↗

arXiv2004

The dynamics of the min proteins of Escherichia coli under the constant external fields

In E. coli the determination of the middle of the cell and the proper placement of the septum is essential to the division of the cell. This step depends on the proteins MinC, MinD, and MinE. Exposure to a constant external field e.g., an electric field or magnetic field may cause the bacteria cell division mechanism to change resulting in an abnormal cytokinesis. To have insight into the effects of an external field on this process, we model the process using a set of the deterministic reaction diffusion equations, which incorporate the influence of an external field, min protein reactions, and diffusion of all species. Using the numerical method, we have found some changes in the dynamics of the oscillations of the min proteins from pole to pole when compared that of without the external field. The results show some interesting effects, which are qualitatively in good agreement with some experimental results.

q-bio.SC↗

arXiv2004

A one-dimensional Lattice Boltzmann method for modeling the dynamic pole-to-pole oscillations of Min proteins for determining the position of the midcell division plane

Determining the middle of the bacteria cell and the proper placement of the septum is essential to the division of the bacterial cell. In E. coli, this process depends on the proteins MinC, MinD, and MinE. Here, the Lattice Boltzmann method (LBM) is used to study the dynamics of the oscillations of the min proteins from pole to pole. This determines the midcell division plane at the cellular level. The LBM is applied to the set of the deterministic reaction diffusion equations proposed by Howard et. al. [1] to describe the dynamics of the Min proteins. The LBM results are in good agreement with those of Howard et al, and agree qualitatively with the experimental results. Our good results indicate that the LBM can be an alternative computational tool for simulating problems dealing with complex biological system which are described by the reaction-diffusion equations.

q-bio.QM↗

arXiv1999

Dynamic scaling in vacancy-mediated disordering

We consider the disordering dynamics of an interacting binary alloy with a small admixture of vacancies which mediate atom-atom exchanges. Starting from a perfectly phase-segregated state, the system is rapidly heated to a temperature in the disordered phase. A suitable disorder parameter, namely, the number of broken bonds, is monitored as a function of time. Using Monte Carlo simulations and a coarse-grained field theory, we show that the late stages of this process exhibit dynamic scaling, characterized by a set of scaling functions and exponents. We discuss the universality of these exponents and comment on some subtleties in the early stages of the disordering process.

cond-mat.stat-mech↗

arXiv1999

Universal aspects of vacancy-mediated disordering dynamics: the effect of external fields

We investigate the disordering of an initially phase-segregated binary alloy, due to a highly mobile defect which couples to an electric or gravitational field. Using both mean-field and Monte Carlo methods, we show that the late stages of this process exhibit dynamic scaling, characterized by a set of exponents and scaling functions. A new scaling variable emerges, associated with the field. While the scaling functions carry information about the field and the boundary conditions, the exponents are universal. They can be computed analytically, in excellent agreement with simulation results.

cond-mat.stat-mech↗

arXiv1999

Binary data corruption due to a Brownian agent II: two dimensions, competing agents, and generalized couplings

This work is a continuation of our previous investigation of binary data corruption due to a Brownian agent [T. J. Newman and W. Triampo, preprint cond-mat/9811237]. We extend our study in three main directions which allow us to make closer contact with real bistable systems. These are i) a detailed analysis of two dimensions, ii) the case of competing agents, and iii) the cases of asymmetric and quenched random couplings. Most of our results are obtained by extending our original phenomenological model, and are supported by extensive numerical simulations.

cond-mat.stat-mech↗

arXiv1998

Binary data corruption due to a Brownian agent

We introduce a model of binary data corruption induced by a Brownian agent (active random walker) on a d-dimensional lattice. A continuum formulation allows the exact calculation of several quantities related to the density of corrupted bits ρ; for example the mean of ρ, and the density-density correlation function. Excellent agreement is found with the results from numerical simulations. We also calculate the probability distribution of ρin d=1, which is found to be log-normal, indicating that the system is governed by extreme fluctuations.

cond-mat.stat-mech↗