The tug-of-war behavior of a Brownian particle in an asymmetric double optical trap with stochastic fluctuations

2018 ◽  
Vol 502 ◽  
pp. 14-20
Author(s):  
Fei Long ◽  
Jia-Pei Zhu
Keyword(s):  
Brownian Particle ◽  
Optical Trap ◽  
Stochastic Fluctuations

scholarly journals Simulation of a Brownian particle in an optical trap

2013 ◽  
Vol 81 (3) ◽  
pp. 224-230 ◽  
Author(s):  
Giorgio Volpe ◽  
Giovanni Volpe
Keyword(s):  
Brownian Particle ◽  
Optical Trap

Stochastic thermodynamics with a Brownian particle in an optical trap (Presentation Recording)

2015 ◽  
Author(s):  
Ignacio A. Martinez ◽  
Édgar Roldán ◽  
Luis Dinis ◽  
Pau Mestres ◽  
Juan M. R. Parrondo ◽  
...  
Keyword(s):  
Brownian Particle ◽  
Optical Trap ◽  
Stochastic Thermodynamics

scholarly journals Steady state of overdamped particles in the non-conservative force field of a simple non-linear model of optical trap

2021 ◽  
Vol 2021 (11) ◽  
pp. 113205
Author(s):  
Matthieu Mangeat ◽  
Thomas Guérin ◽  
David S Dean
Keyword(s):  
Steady State ◽  
Force Field ◽  
Brownian Particle ◽  
Optical Trap ◽  
Three Dimensional ◽  
Planck Equation ◽  
Steady State Probability ◽  
Trapped Particles ◽  
Scattering Force ◽  
Optically Trapped

Abstract Optically trapped particles are often subject to a non-conservative scattering force arising from radiation pressure. In this paper, we present an exact solution for the steady state statistics of an overdamped Brownian particle subjected to a commonly used force field model for an optical trap. The model is the simplest of its kind that takes into account non-conservative forces. In particular, we present the exact results for certain marginals of the full three-dimensional steady state probability distribution, in addition to results for the toroidal probability currents that are present in the steady state, as well as for the circulation of these currents. Our analytical results are confirmed by numerical solution of the steady state Fokker–Planck equation.

scholarly journals Biomechanics of Neutrophil Tethers

Life ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 515
Author(s):  
Andrea Cugno ◽  
Alex Marki ◽  
Klaus Ley
Keyword(s):  
Cell Activation ◽  
Optical Trap ◽  
Biomechanical Properties ◽  
Force Microscopy ◽  
Advantages And Disadvantages ◽  
Atomic Force ◽  
Microfluidic Flow ◽  
Biomembrane Force Probe ◽  
Membrane Reservoir

Leukocytes, including neutrophils, which are propelled by blood flow, can roll on inflamed endothelium using transient bonds between selectins and their ligands, and integrins and their ligands. When such receptor–ligand bonds last long enough, the leukocyte microvilli become extended and eventually form thin, 20 m long tethers. Tether formation can be observed in blood vessels in vivo and in microfluidic flow chambers. Tethers can also be extracted using micropipette aspiration, biomembrane force probe, optical trap, or atomic force microscopy approaches. Here, we review the biomechanical properties of leukocyte tethers as gleaned from such measurements and discuss the advantages and disadvantages of each approach. We also review and discuss viscoelastic models that describe the dependence of tether formation on time, force, rate of loading, and cell activation. We close by emphasizing the need to combine experimental observations with quantitative models and computer simulations to understand how tether formation is affected by membrane tension, membrane reservoir, and interactions of the membrane with the cytoskeleton.

scholarly journals Compact ultracold electron source based on a grating magneto-optical trap

2019 ◽  
Vol 22 (2) ◽  
Author(s):  
J. G. H. Franssen ◽  
T. C. H. de Raadt ◽  
M. A. W. van Ninhuijs ◽  
O. J. Luiten
Keyword(s):  
Optical Trap ◽  
Electron Source ◽  
Magneto Optical Trap

scholarly journals Orthogonal control of mean and variability of endogenous genes in a human cell line

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Alain R. Bonny ◽  
João Pedro Fonseca ◽  
Jesslyn E. Park ◽  
Hana El-Samad
Keyword(s):  
Mammalian Cells ◽  
Human Cell Line ◽  
Transcriptional Level ◽  
Clear Understanding ◽  
Gene Expression Noise ◽  
Endogenous Gene ◽  
Basal Expression ◽  
Stochastic Fluctuations ◽  
Human Genes ◽  
Synthetic Circuit

AbstractStochastic fluctuations at the transcriptional level contribute to isogenic cell-to-cell heterogeneity in mammalian cell populations. However, we still have no clear understanding of the repercussions of this heterogeneity, given the lack of tools to independently control mean expression and variability of a gene. Here, we engineer a synthetic circuit to modulate mean expression and heterogeneity of transgenes and endogenous human genes. The circuit, a Tunable Noise Rheostat (TuNR), consists of a transcriptional cascade of two inducible transcriptional activators, where the output mean and variance can be modulated by two orthogonal small molecule inputs. In this fashion, different combinations of the inputs can achieve the same mean but with different population variability. With TuNR, we achieve low basal expression, over 1000-fold expression of a transgene product, and up to 7-fold induction of the endogenous gene NGFR. Importantly, for the same mean expression level, we are able to establish varying degrees of heterogeneity in expression within an isogenic population, thereby decoupling gene expression noise from its mean. TuNR is therefore a modular tool that can be used in mammalian cells to enable direct interrogation of the implications of cell-to-cell variability.

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