scholarly journals Mechanical properties of end-crosslinked entangled polymer networks using sliplink Brownian dynamics simulations

2006 ◽  
Vol 46 (1) ◽  
pp. 95-109 ◽  
Author(s):  
Julian Oberdisse ◽  
Giovanni Ianniruberto ◽  
Francesco Greco ◽  
Giuseppe Marrucci
2015 ◽  
Vol 12 (112) ◽  
pp. 20150876 ◽  
Author(s):  
Sophie Sacquin-Mora

The determination of a protein's folding nucleus, i.e. a set of native contacts playing an important role during its folding process, remains an elusive yet essential problem in biochemistry. In this work, we investigate the mechanical properties of 70 protein structures belonging to 14 protein families presenting various folds using coarse-grain Brownian dynamics simulations. The resulting rigidity profiles combined with multiple sequence alignments show that a limited set of rigid residues, which we call the consensus nucleus, occupy conserved positions along the protein sequence. These residues' side chains form a tight interaction network within the protein's core, thus making our consensus nuclei potential folding nuclei. A review of experimental and theoretical literature shows that most (above 80%) of these residues were indeed identified as folding nucleus member in earlier studies.


Soft Matter ◽  
2015 ◽  
Vol 11 (40) ◽  
pp. 7877-7887 ◽  
Author(s):  
Navid Kazem ◽  
Carmel Majidi ◽  
Craig E. Maloney

We perform Brownian dynamics simulations to study the gelation of suspensions of attractive, rod-like particles. We show that if the attraction is sufficiently corrugated or patchy, over time, a rigid space-spanning network will form. Surprisingly, the structural and mechanical properties are non-monotonic in the fraction of the surface.


Author(s):  
Konstantinos Manikas ◽  
Markus Hütter ◽  
Patrick D. Anderson

AbstractThe effect of time-dependent external fields on the structures formed by particles with induced dipoles dispersed in a viscous fluid is investigated by means of Brownian Dynamics simulations. The physical effects accounted for are thermal fluctuations, dipole-dipole and excluded volume interactions. The emerging structures are characterised in terms of particle clusters (orientation, size, anisotropy and percolation) and network structure. The strength of the external field is increased in one direction and then kept constant for a certain amount of time, with the structure formation being influenced by the slope of the field-strength increase. This effect can be partially rationalized by inhomogeneous time re-scaling with respect to the field strength, however, the presence of thermal fluctuations makes the scaling at low field strength inappropriate. After the re-scaling, one can observe that the lower the slope of the field increase, the more network-like and the thicker the structure is. In the second part of the study the field is also rotated instantaneously by a certain angle, and the effect of this transition on the structure is studied. For small rotation angles ($$\theta \le 20^{{\circ }}$$ θ ≤ 20 ∘ ) the clusters rotate but stay largely intact, while for large rotation angles ($$\theta \ge 80^{{\circ }}$$ θ ≥ 80 ∘ ) the structure disintegrates and then reforms, due to the nature of the interactions (parallel dipoles with perpendicular inter-particle vector repel each other). For intermediate angles ($$20<\theta <80^{{\circ }}$$ 20 < θ < 80 ∘ ), it seems that, during rotation, the structure is altered towards a more network-like state, as a result of cluster fusion (larger clusters). The details provided in this paper concern an electric field, however, all results can be projected into the case of a magnetic field and paramagnetic particles.


2021 ◽  
Author(s):  
Dillip Kumar Mohapatra ◽  
Philip James Camp ◽  
John Philip

We probe the influence of particle size polydispersity on field-induced structures and structural transitions in magnetic fluids (ferrofluids) using phase contrast optical microscopy, light scattering and Brownian dynamics simulations. Three...


Author(s):  
Oliver Henrich ◽  
Fabian Weysser ◽  
Michael E. Cates ◽  
Matthias Fuchs

Brownian dynamics simulations of bidisperse hard discs moving in two dimensions in a given steady and homogeneous shear flow are presented close to and above the glass transition density. The stationary structure functions and stresses of shear-melted glass are compared quantitatively to parameter-free numerical calculations of monodisperse hard discs using mode coupling theory within the integration through transients framework. Theory qualitatively explains the properties of the yielding glass but quantitatively overestimates the shear-driven stresses and structural anisotropies.


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