scholarly journals Multiscale mechanics and temporal evolution of vimentin intermediate filament networks

2021 ◽  
Vol 118 (27) ◽  
pp. e2102026118
Author(s):  
Anna V. Schepers ◽  
Charlotta Lorenz ◽  
Peter Nietmann ◽  
Andreas Janshoff ◽  
Stefan Klumpp ◽  
...  
Keyword(s):  
Particle Tracking ◽  
Temporal Evolution ◽  
Quantitative Information ◽  
Multiscale Approach ◽  
Filament Length ◽  
Single Filament ◽  
Multiscale Mechanics ◽  
Filament Networks ◽  
Kinetics Of ◽  
Vimentin Intermediate Filament

The cytoskeleton, an intricate network of protein filaments, motor proteins, and cross-linkers, largely determines the mechanical properties of cells. Among the three filamentous components, F-actin, microtubules, and intermediate filaments (IFs), the IF network is by far the most extensible and resilient to stress. We present a multiscale approach to disentangle the three main contributions to vimentin IF network mechanics—single-filament mechanics, filament length, and interactions between filaments—including their temporal evolution. Combining particle tracking, quadruple optical trapping, and computational modeling, we derive quantitative information on the strength and kinetics of filament interactions. Specifically, we find that hydrophobic contributions to network mechanics enter mostly via filament-elongation kinetics, whereas electrostatics have a direct influence on filament–filament interactions.

scholarly journals Multiscale mechanics and temporal evolution of vimentin intermediate filament networks

2021 ◽  
Author(s):  
Anna V. Schepers ◽  
Charlotta Lorenz ◽  
Peter Nietmann ◽  
Andreas Janshoff ◽  
Stefan Klumpp ◽  
...  
Keyword(s):  
Particle Tracking ◽  
Temporal Evolution ◽  
Quantitative Information ◽  
Multiscale Approach ◽  
Filament Length ◽  
Single Filament ◽  
Multiscale Mechanics ◽  
Filament Networks ◽  
Kinetics Of ◽  
Vimentin Intermediate Filament

AbstractThe cytoskeleton, an intricate network of protein filaments, motor proteins, and crosslinkers, largely determines the mechanical properties of cells. Among the three filamentous components, F-actin, microtubules, and intermediate filaments (IFs), the IF network is by far the most extensible and resilient to stress. We present a multiscale approach to disentangle the three main contributions to vimentin IF network mechanics – single filament mechanics, filament length, and interactions between filaments – including their temporal evolution. Combining particle tracking, quadruple optical trapping and computational modeling, we derive quantitative information on the strength and kinetics of filament interactions. Specifically, we find that hydrophobic contributions to network mechanics enter mostly via filament elongation kinetics, whereas electrostatics have a direct influence on filament–filament interactions. These results indicate that cells might need to explicitly suppress attractive interactions to re-organize the extremely stable cellular vimentin network.

Modelling of the damage development in carbon/epoxy laminates subjected to combined seawater ageing and mechanical loading

2016 ◽  
Vol 232 (9) ◽  
pp. 761-768 ◽  
Author(s):  
N Carrere ◽  
N Tual ◽  
T Bonnemains ◽  
E Lolive ◽  
P Davies
Keyword(s):  
Applied Load ◽  
Epoxy Composite ◽  
Damage Model ◽  
Crack Density ◽  
Damage Threshold ◽  
Multiscale Approach ◽  
Damage Development ◽  
Finite Fracture Mechanics ◽  
Physically Based ◽  
Kinetics Of

In this study, a damage model that accounts for the effect of seawater ageing is proposed. The model is based on a failure criterion that takes into account the effect of the ply thickness, while the kinetics of the damage development are based on a Finite Fracture Mechanics approach. The stiffness degradation is identified by a multiscale approach. The parameters of the model are physically based which facilitates the identification and the coupling with the ageing. These and their evolution as a function of the time of immersion in seawater have been identified for a carbon/epoxy composite. The changes in crack density as a function of the applied load for three ageing times are quite well predicted by the model. The model explains why the damage threshold is strongly influenced by the ageing while the kinetics of the crack propagation remain quasi-constant.

Vimentin Intermediate Filament Formation: In Vitro Measurement and Mathematical Modeling of the Filament Length Distribution during Assembly†

Langmuir ◽  
2009 ◽  
Vol 25 (15) ◽  
pp. 8817-8823 ◽  
Author(s):  
Stéphanie Portet ◽  
Norbert Mücke ◽  
Robert Kirmse ◽  
Jörg Langowski ◽  
Michael Beil ◽  
...  
Keyword(s):  
Mathematical Modeling ◽  
Intermediate Filament ◽  
Length Distribution ◽  
Filament Length ◽  
Filament Formation ◽  
Vimentin Intermediate Filament

scholarly journals In situ monitoring of hydrothermal reactions by X-ray diffraction with Bragg–Brentano geometry

2020 ◽  
Vol 53 (4) ◽  
pp. 1163-1166
Author(s):  
Karsten Mesecke ◽  
Winfried Malorny ◽  
Laurence N. Warr
Keyword(s):  
Quantitative Information ◽  
In Situ Monitoring ◽  
X Ray Diffraction ◽  
Hydrothermal Conditions ◽  
X Ray ◽  
Saturated Vapour Pressure ◽  
Concrete Production ◽  
Aerated Concrete ◽  
Kinetics Of

This note describes an autoclave chamber developed and constructed by Anton Paar and its application for in situ experiments under hydrothermal conditions. Reactions of crystalline phases can be studied by successive in situ measurements on a conventional laboratory X-ray diffractometer with Bragg–Brentano geometry at temperatures <483 K and saturated vapour pressure <2 MPa. Variations in the intensity of X-ray diffraction reflections of both reactants and products provide quantitative information for studying the reaction kinetics of both dissolution and crystal growth. Feasibility is demonstrated by studying a cementitious mixture used for autoclaved aerated concrete production. During a period of 5.7 h at 466 K and 1.35 MPa, the crystallization of torbermorite and the partial consumption of quartz were monitored.

scholarly journals Torsional stress generated by ADF/cofilin on cross-linked actin filaments boosts their severing

2019 ◽  
Vol 116 (7) ◽  
pp. 2595-2602 ◽  
Author(s):  
Hugo Wioland ◽  
Antoine Jegou ◽  
Guillaume Romet-Lemonne
Keyword(s):  
Simple Model ◽  
Mechanical Stress ◽  
Rate Constant ◽  
Single Molecule ◽  
Actin Filaments ◽  
Torsional Stress ◽  
Local Curvature ◽  
Single Filament ◽  
Filament Networks ◽  
Filament Network

Proteins of the actin depolymerizing factor (ADF)/cofilin family are the central regulators of actin filament disassembly. A key function of ADF/cofilin is to sever actin filaments. However, how it does so in a physiological context, where filaments are interconnected and under mechanical stress, remains unclear. Here, we monitor and quantify the action of ADF/cofilin in different mechanical situations by using single-molecule, single-filament, and filament network techniques, coupled to microfluidics. We find that local curvature favors severing, while tension surprisingly has no effect on cofilin binding and weakly enhances severing. Remarkably, we observe that filament segments that are held between two anchoring points, thereby constraining their twist, experience a mechanical torque upon cofilin binding. We find that this ADF/cofilin-induced torque does not hinder ADF/cofilin binding, but dramatically enhances severing. A simple model, which faithfully recapitulates our experimental observations, indicates that the ADF/cofilin-induced torque increases the severing rate constant 100-fold. A consequence of this mechanism, which we verify experimentally, is that cross-linked filament networks are severed by cofilin far more efficiently than nonconnected filaments. We propose that this mechanochemical mechanism is critical to boost ADF/cofilin’s ability to sever highly connected filament networks in cells.

scholarly journals Thermodynamics and kinetics of DNA nanotube polymerization from single-filament measurements

2015 ◽  
Vol 6 (4) ◽  
pp. 2252-2267 ◽  
Author(s):  
Rizal F. Hariadi ◽  
Bernard Yurke ◽  
Erik Winfree
Keyword(s):  
Kinetic Parameters ◽  
Single Filament ◽  
Common Features ◽  
Thermodynamics And Kinetics ◽  
Polymer Models ◽  
Thermodynamic And Kinetic Parameters ◽  
Model Sharing ◽  
Dna Nanotube ◽  
Kinetics Of

Single-filament measurement of the thermodynamic and kinetic parameters of DNA nanotube assembly supports a polymerization/depolymerization model sharing common features with cytoskeletal polymer models.

scholarly journals Kinetics of structure formation of a composite mortar with nano-additives based on aluminium

2020 ◽  
Vol 161 ◽  
pp. 01099
Author(s):  
S.Yu. Efremova ◽  
M.I. Panfilova ◽  
N.I. Zubrev ◽  
O.V. Novoselova
Keyword(s):  
Structure Formation ◽  
Temporal Evolution ◽  
Initial Period ◽  
Control Sample ◽  
Injection Efficiency ◽  
Evolution Of Structure ◽  
Nano Additives ◽  
Kinetics Of

This paper discusses the possibility of using aluminum-containing nano-additives as structure modifiers of composite mortar in order to ensure safety and durability of rubble foundation. Higher injection efficiency can be achieved by integrating the composite mortar into the foundation body. The temporal evolution of structure formation in composite mortar with various contents of boehmite and aluminosilicate nanotubes (ANT) was studied. The optimal concentrations of additives were determined at which the rate of structure formation reaches its maximum. It was revealed that ANT additives accelerate the hardening time of the composite mortar by 1.3 times in comparison with boehmite additives. The greatest impact on accelerating the structure formation in the initial period is achieved by adding 0.125% aluminosilicate tubes to the mass of cement. It was found that in this case, the duration of flowability loss of the composite mortar is reduced by a factor of three compared with that of the control sample.

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