Conformational Changes and Dynamics during Adsorption of Macromolecules with Different Degree of Polymerization Studied by Monte Carlo Simulations

2018 ◽  
Vol 27 (4) ◽  
pp. 1800012 ◽  
Author(s):  
Roser Sabater i Serra ◽  
Constantino Torregrosa Cabanilles ◽  
José María Meseguer Dueñas ◽  
José Luis Gómez Ribelles ◽  
José Molina-Mateo
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Simulations ◽  
Conformational Changes ◽  
Degree Of Polymerization

Monte Carlo Simulation of Adsorption of Di-Block Copolymers

1988 ◽  
Vol 140 ◽  
Author(s):  
Wan Y. Shih ◽  
Wei-Heng Shill ◽  
Ilhan A. Aksay
Keyword(s):  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Block Copolymer ◽  
Block Copolymers ◽  
Monte Carlo Simulations ◽  
Degree Of Polymerization ◽  
Radius Of Gyration ◽  
Adsorbed Layers ◽  
Experimental Findings ◽  
Repulsive Forces

AbstractIn this paper we are concerned with the morphology of the polymers adsorbedon surfaces, in particular di-block copolymers. Our work is motivated by the experimental findings of Fladziioannou et al. [1] on the steric forces between two adsorbed layers of di-block poly(vinyl-2-pyridine)\ polystyrene (PV2P\ PS) copolymer on mica surfaces. The PV2P block binds strongly on the mica surfaces and the PS block extends into thesolvent toluene (good solvent for PS). Hadziiouannou et al. found that the repulsive forces between the two surfaces start at a distance 1) larger than 10 times the radius of gyration RG of a free P' in toluene. Furthermore, the starting distance D increases with increasing degree of polymerization N of PS in a fashion I) ~ Na with a close to I. We,tudy the adsorption of di-block copolymer with Monte Carlo simulations. The Monte Carlo simulations are especially powerful in dealing with kinetics which is important in systems where hysteresis is observed II1 and cannot be appropriately taken into account by analytical (or numerical) calculations based onequilibrium assumptions.

scholarly journals Conformational changes of globular proteins upon adsorption on a hydrophobic surface

2014 ◽  
Vol 16 (23) ◽  
pp. 11698-11707 ◽  
Author(s):  
Yevgeny Moskovitz ◽  
Simcha Srebnik
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Simulations ◽  
Conformational Changes ◽  
Thermal Denaturation ◽  
Hydrophobic Surface ◽  
Globular Proteins ◽  
Coarse Grained ◽  
Adsorbed Protein

Coarse-grained Monte Carlo simulations are used to study thermal denaturation of small globular proteins adsorbed on a hydrophobic surface. Though helices are more stable than sheets, they are highly deformed in the adsorbed protein.

Monte Carlo Simulations of the Kinetics of Protein Adsorption

1998 ◽  
Vol 05 (02) ◽  
pp. 615-634 ◽  
Author(s):  
V. P. Zhdanov ◽  
B. Kasemo
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Simulations ◽  
Protein Adsorption ◽  
Rate Constant ◽  
Conformational Changes ◽  
Adsorption Kinetics ◽  
Metastable States ◽  
First Order ◽  
Kinetics Of ◽  
Denaturation Rate

The past decade has been characterized by rapid progress in Monte Carlo simulations of protein folding in a solution. This review summarizes the main results obtained in the field, as a background to the major topic, namely corresponding advances in simulations of protein adsorption kinetics at solid–liquid interfaces. The latter occur via diffusion in the liquid towards the interface followed by actual adsorption, and subsequent irreversible conformational changes, resulting in more or less pronounced denaturation of the native protein structure. The conventional kinetic models describing these steps are based on the assumption that the denaturation transitions obey the first-order law with a single value of the denaturation rate constant kr. The validity of this assumption has been studied in recent lattice Monte Carlo simulations of denaturation of model protein-like molecules with different types of the monomer–monomer interactions. The results obtained indicate that, due to trapping in metastable states, (i) the transition of a molecule to the denatured state is usually nonexponential in time, i.e. it does not obey the first-order law, and (ii) the denaturation transitions of an ensemble of different molecules are characterized by different time scales, i.e. the denaturation process cannot be described by a single rate constant kr. One should, rather, introduce a distribution of values of this rate constant (physically, different values of kr reflect the fact that the transitions to the altered state occurs via different metastable states). The phenomenological kinetics of irreversible adsorption of proteins with and without a distribution of the denaturation rate constant values have been calculated in the limits where protein diffusion in the solution is, respectively, rapid or slow. In both cases, the adsorption kinetics with a distribution of kr are found to be close to those with a single–valued rate constant kr, provided that the average value of kr in the former case is equal to kr in the latter case. This conclusion holds even for wide distributions of kr. The consequences of this finding for the fitting of global experimental kinetics on the basis of phenomenological equations are briefly discussed.

Low-voltage EDS of magnesium ferrite Dendrites in a FEG-SEM

1996 ◽  
Vol 54 ◽  
pp. 478-479
Author(s):  
Matthew T. Johnson ◽  
Ian M. Anderson ◽  
Jim Bentley ◽  
C. Barry Carter
Keyword(s):  
Monte Carlo ◽  
Quantitative Analysis ◽  
Monte Carlo Simulations ◽  
Cross Section ◽  
Spatial Resolution ◽  
Low Voltage ◽  
Magnesium Ferrite ◽  
X Ray ◽  
Interaction Volume ◽  
Ferrite Spinel

Energy-dispersive X-ray spectrometry (EDS) performed at low (≤ 5 kV) accelerating voltages in the SEM has the potential for providing quantitative microanalytical information with a spatial resolution of ∼100 nm. In the present work, EDS analyses were performed on magnesium ferrite spinel [(MgxFe1−x)Fe2O4] dendrites embedded in a MgO matrix, as shown in Fig. 1. spatial resolution of X-ray microanalysis at conventional accelerating voltages is insufficient for the quantitative analysis of these dendrites, which have widths of the order of a few hundred nanometers, without deconvolution of contributions from the MgO matrix. However, Monte Carlo simulations indicate that the interaction volume for MgFe2O4 is ∼150 nm at 3 kV accelerating voltage and therefore sufficient to analyze the dendrites without matrix contributions.Single-crystal {001}-oriented MgO was reacted with hematite (Fe2O3) powder for 6 h at 1450°C in air and furnace cooled. The specimen was then cleaved to expose a clean cross-section suitable for microanalysis.

MONTE CARLO SIMULATIONS OF ELECTRON DRIFT VELOCITIES IN THE NOBLE GASES AND THEIR MIXTURES

1979 ◽  
Vol 40 (C7) ◽  
pp. C7-63-C7-64
Author(s):  
A. J. Davies ◽  
J. Dutton ◽  
C. J. Evans ◽  
A. Goodings ◽  
P.K. Stewart
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Simulations ◽  
Noble Gases ◽  
Electron Drift
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