scholarly journals The role of temperature in the rigidity-controlled fracture of elastic networks

Soft Matter ◽  
2020 ◽  
Vol 16 (43) ◽  
pp. 9975-9985
Author(s):  
Justin Tauber ◽  
Aimée R. Kok ◽  
Jasper van der Gucht ◽  
Simone Dussi
Keyword(s):  
Thermal Fluctuations ◽  
Central Force ◽  
Dependent Effect ◽  
Elastic Networks ◽  
Controlled Fracture

Thermal fluctuations have a rigidity-dependent effect on the failure response of central-force spring networks, promoting diffuse damage via the delocalization of stress.

scholarly journals Role of thermal fluctuations in biological copying mechanisms

2021 ◽  
Vol 103 (3) ◽  
Author(s):  
Moupriya Das ◽  
Holger Kantz
Keyword(s):  
Thermal Fluctuations

Understanding the role of thermal fluctuations in DNA looping

2007 ◽  
Author(s):  
David P. Wilson ◽  
Todd Lillian ◽  
Sachin Goyal ◽  
Alexei V. Tkachenko ◽  
Noel C. Perkins ◽  
...  
Keyword(s):  
Thermal Fluctuations ◽  
Dna Looping

scholarly journals Molecular machines operating on the nanoscale: from classical to quantum

2016 ◽  
Vol 7 ◽  
pp. 328-350 ◽  
Author(s):  
Igor Goychuk
Keyword(s):  
Molecular Motors ◽  
High Performance ◽  
Molecular Machines ◽  
Thermal Fluctuations ◽  
Maximum Power ◽  
Thermodynamic Efficiency ◽  
Fluctuation Dissipation ◽  
Fluctuation Dissipation Theorem ◽  
Physical Features

The main physical features and operating principles of isothermal nanomachines in the microworld, common to both classical and quantum machines, are reviewed. Special attention is paid to the dual, constructive role of dissipation and thermal fluctuations, the fluctuation–dissipation theorem, heat losses and free energy transduction, thermodynamic efficiency, and thermodynamic efficiency at maximum power. Several basic models are considered and discussed to highlight generic physical features. This work examines some common fallacies that continue to plague the literature. In particular, the erroneous beliefs that one should minimize friction and lower the temperature for high performance of Brownian machines, and that the thermodynamic efficiency at maximum power cannot exceed one-half are discussed. The emerging topic of anomalous molecular motors operating subdiffusively but very efficiently in the viscoelastic environment of living cells is also discussed.

scholarly journals Mucin inhibitsPseudomonas aeruginosabiofilm formation by significantly enhancing twitching motility

2014 ◽  
Vol 60 (3) ◽  
pp. 155-166 ◽  
Author(s):  
Cecily L. Haley ◽  
Cassandra Kruczek ◽  
Uzma Qaisar ◽  
Jane A. Colmer-Hamood ◽  
Abdul N. Hamood
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Type Iv Pili ◽  
Dependent Manner ◽  
Twitching Motility ◽  
Strain Pao1 ◽  
Concentration Dependent Manner ◽  
Dependent Effect ◽  
Type Iv ◽  
Biofilm Development

In Pseudomonas aeruginosa, type IV pili (TFP)-dependent twitching motility is required for development of surface-attached biofilm (SABF), yet excessive twitching motility is detrimental once SABF is established. In this study, we show that mucin significantly enhanced twitching motility and decreased SABF formation in strain PAO1 and other P. aeruginosa strains in a concentration-dependent manner. Mucin also disrupted partially established SABF. Our analyses revealed that mucin increased the amount of surface pilin and enhanced transcription of the pilin structural gene pilA. Mucin failed to enhance twitching motility in P. aeruginosa mutants defective in genes within the pilin biogenesis operons pilGHI/pilJK-chpA-E. Furthermore, mucin did not enhance twitching motility nor reduce biofilm development by chelating iron. We also examined the role of the virulence factor regulator Vfr in the effect of mucin. In the presence or absence of mucin, PAOΔvfr produced a significantly reduced SABF. However, mucin partially complemented the twitching motility defect of PAOΔvfr. These results suggest that mucin interferes with SABF formation at specific concentrations by enhancing TFP synthesis and twitching motility, that this effect, which is iron-independent, requires functional Vfr, and only part of the Vfr-dependent effect of mucin on SABF development occurs through twitching motility.

scholarly journals Biomimetic tissue models reveal the role of hyaluronan in melanoma proliferation and invasion

2020 ◽  
Vol 8 (5) ◽  
pp. 1405-1417 ◽  
Author(s):  
Jiranuwat Sapudom ◽  
Khiet-Tam Nguyen ◽  
Steve Martin ◽  
Tom Wippold ◽  
Stephanie Möller ◽  
...  
Keyword(s):  
Matrix Models ◽  
Alternative Explanation ◽  
Dependent Effect ◽  
Size Dependent ◽  
Melanoma Progression ◽  
Tissue Models ◽  
Proliferation And Invasion ◽  
Melanoma Growth

Biomimetic matrix models demonstrate the role of the size-dependent effect of hyaluronan in melanoma progression and reveal an alternative explanation for in vivo findings of hyaluronan dependent melanoma growth.

Hydrodynamic diffusion in active microrheology of non-colloidal suspensions: the role of interparticle forces

2015 ◽  
Vol 785 ◽  
pp. 189-218 ◽  
Author(s):  
N. J. Hoh ◽  
R. N. Zia
Keyword(s):  
Brownian Motion ◽  
External Force ◽  
Hydrodynamic Limit ◽  
Thermal Fluctuations ◽  
Longitudinal Force ◽  
Experimental Measurements ◽  
Interparticle Forces ◽  
Pair Density ◽  
Far From Equilibrium

Hydrodynamic diffusion in the absence of Brownian motion is studied via active microrheology in the ‘pure-hydrodynamic’ limit, with a view towards elucidating the transition from colloidal microrheology to the non-colloidal limit, falling-ball rheometry. The phenomenon of non-Brownian force-induced diffusion in falling-ball rheometry is strictly hydrodynamic in nature; in contrast, analogous force-induced diffusion in colloids is deeply connected to the presence of a diffusive boundary layer even when Brownian motion is very weak compared with the external force driving the ‘probe’ particle. To connect these two limits, we derive an expression for the force-induced diffusion in active microrheology of hydrodynamically interacting particles via the Smoluchowski equation, where thermal fluctuations play no role. While it is well known that the microstructure is spherically symmetric about the probe in this limit, fluctuations in the microstructure need not be – and indeed lead to a diffusive spread of the probe trajectory. The force-induced diffusion is anisotropic, with components along and transverse to the line of external force. The latter is identically zero owing to the fore–aft symmetry of pair trajectories in Stokes flow. In a naïve first approach, the vanishing relative hydrodynamic mobility at contact between the probe and an interacting bath particle was assumed to eliminate all physical contribution from interparticle forces, whereby advection alone drove structural evolution in pair density and microstructural fluctuations. With such an approach, longitudinal force-induced diffusion vanishes in the absence of Brownian motion, a result that contradicts well-known experimental measurements of such diffusion in falling-ball rheometry. To resolve this contradiction, the probe–bath-particle interaction at contact was carefully modelled via an excluded annulus. We find that interparticle forces play a crucial role in encounters between particles in the hydrodynamic limit – as they must, to balance the advective flux. Accounting for this force results in a longitudinal force-induced diffusion $D_{\Vert }=1.26aU_{S}{\it\phi}$, where $a$ is the probe size, $U_{S}$ is the Stokes velocity and ${\it\phi}$ is the volume fraction of bath particles, in excellent qualitative and quantitative agreement with experimental measurements in, and theoretical predictions for, macroscopic falling-ball rheometry. This new model thus provides a continuous connection between micro- and macroscale rheology, as well as providing important insight into the role of interparticle forces for diffusion and rheology even in the limit of pure hydrodynamics: interparticle forces give rise to non-Newtonian rheology in strongly forced suspensions. A connection is made between the flow-induced diffusivity and the intrinsic hydrodynamic microviscosity which recovers a precise balance between fluctuation and dissipation in far from equilibrium suspensions; that is, diffusion and drag arise from a common microstructural origin even far from equilibrium.

Role of Thermal Fluctuations in a Classical Dynamical Model for Fission

1982 ◽  
Vol 25 (4) ◽  
pp. 517-521 ◽  
Author(s):  
S K Samaddar ◽  
D Sperber ◽  
M Zielinska-Pfabé ◽  
M I Sobel
Keyword(s):  
Thermal Fluctuations ◽  
Dynamical Model
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