scholarly journals Fibrinogen and Fibrin Differentially Regulate the Local Hydrodynamic Environment in Neutrophil–Tumor Cell–Endothelial Cell Adhesion System

2020 ◽  
Vol 11 (1) ◽  
pp. 79
Author(s):  
Yi Fu ◽  
Ang Li ◽  
Jie Wu ◽  
Robert F. Kunz ◽  
Ren Sun ◽  
...  
Keyword(s):  
Shear Flow ◽  
Dynamics Simulation ◽  
Adherent Cell ◽  
Human Beings ◽  
Endothelial Monolayer ◽  
Soluble Fibrin ◽  
Shear Rates ◽  
Relative Shear ◽  
Particle Imaging ◽  
Hydrodynamic Environment

As cancer is one of the major fatal diseases for human beings worldwide, the metastasis of tumor cells (TCs) from a blood vessel to an adjacent organ has become a focus of research. A tumor metastasis theory named the “two-step theory” pointed out that polymorphnuclear neutrophils (PMNs) could facilitate TC adhesion on an endothelial monolayer under flow, which was regulated by shear flow and promoted by fibrinogen and fibrin. In order to further understand the role of hydrodynamics played in the “two-step theory”, we improved our side-view micro-particle imaging velocimetry (PIV) system and successfully measured the flow velocity profiles around adherent PMNs and TCs on an endothelial monolayer in the presence of soluble fibrinogen or fibrin under shear flow. Combined with a computational fluid dynamics simulation, we found that: (1) soluble fibrinogen and fibrin influenced the variations of relative shear rates above an adhered PMN and an adherent TC at different PMN-to-TC position states; (2) compared with soluble fibrinogen, soluble fibrin made the curves of relative shear rates above an adherent cell flatter. Soluble fibrin might increase the collision frequency and affect the contact time and contact area between PMNs, TCs, and endothelium cells, resulting in the enhancement of TC adhesion and retention on an endothelial monolayer.

Coarse-grained molecular dynamics simulation on the placement of nanoparticles within symmetric diblock copolymers under shear flow

2008 ◽  
Vol 128 (16) ◽  
pp. 164909 ◽  
Author(s):  
Vibha Kalra ◽  
Sergio Mendez ◽  
Fernando Escobedo ◽  
Yong Lak Joo
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulation ◽  
Shear Flow ◽  
Diblock Copolymers ◽  
Dynamics Simulation ◽  
Coarse Grained ◽  
Coarse Grained Molecular Dynamics

scholarly journals Effects of posture on shear rates in human brachial and superficial femoral arteries

2008 ◽  
Vol 294 (4) ◽  
pp. H1833-H1839 ◽  
Author(s):  
S. C. Newcomer ◽  
C. L. Sauder ◽  
N. T. Kuipers ◽  
M. H. Laughlin ◽  
C. A. Ray
Keyword(s):  
Shear Rate ◽  
Femoral Artery ◽  
Brachial Artery ◽  
Superficial Femoral Artery ◽  
Upright Posture ◽  
Brachial Artery Diameter ◽  
Shear Rates ◽  
Femoral Arteries ◽  
Lower Shear ◽  
Relative Shear

Shear rate is significantly lower in the superficial femoral compared with the brachial artery in the supine posture. The relative shear rates in these arteries of subjects in the upright posture (seated and/or standing) are unknown. The purpose of this investigation was to test the hypothesis that upright posture (seated and/or standing) would produce greater shear rates in the superficial femoral compared with the brachial artery. To test this hypothesis, Doppler ultrasound was used to measure mean blood velocity (MBV) and diameter in the brachial and superficial femoral arteries of 21 healthy subjects after being in the supine, seated, and standing postures for 10 min. MBV was significantly higher in the brachial compared with the superficial femoral artery during upright postures. Superficial femoral artery diameter was significantly larger than brachial artery diameter. However, posture had no significant effect on either brachial or superficial femoral artery diameter. The calculated shear rate was significantly greater in the brachial (73 ± 5, 91 ± 11, and 97 ± 13 s−1) compared with the superficial femoral (53 ± 4, 39 ± 77, and 44 ± 5 s−1) artery in the supine, seated, and standing postures, respectively. Contrary to our hypothesis, our current findings indicate that mean shear rate is lower in the superficial femoral compared with the brachial artery in the supine, seated, and standing postures. These findings of lower shear rates in the superficial femoral artery may be one mechanism for the higher propensity for atherosclerosis in the arteries of the leg than of the arm.

scholarly journals Brownian Dynamics Simulation for Bimodal Suspensions of Oblong-Particles under Shear Flow.

2000 ◽  
Vol 28 (1) ◽  
pp. 21-26 ◽  
Author(s):  
Mori Noriyasu ◽  
Yamamoto Ichiro ◽  
Nakamura Kiyoji
Keyword(s):  
Shear Flow ◽  
Brownian Dynamics ◽  
Dynamics Simulation ◽  
Brownian Dynamics Simulation

In Vitro Imaging Technique of Cell Adhesion

2002 ◽  
Author(s):  
Chen Dong
Keyword(s):  
Shear Stress ◽  
Cell Adhesion ◽  
Shear Flow ◽  
Imaging Technique ◽  
Contact Length ◽  
Adherent Cell ◽  
Side View ◽  
Cell Deformability ◽  
Hydrodynamic Shear

It is the first object of this article to contribute a side-view imaging technique to investigate adhesion to a surface-immobilized ICAM-1 in shear flow, wherein T-leukemic Jurket cells have been used. A side view image has revealed that the cell adhesion on ICAM-1 under flow conditions in vitro is quasistratic. Changes in flow shear stress, cell deformability, or substrate ligand strength resulted in a significant change in the characteristic adhesion binding time and contact length. The elongation of cells in shear flow tempers hydrodynamic shear forces on the cell, which affects the transients in cell-surface adhesion. It is the second object to calculate a 3-D flow field with shear stress acting on an adherent cell based on the shape of the cell obtained from the image. The application of the side-view imaging technique and the image analysis may provide a practical assay to reveal fundamental behavior of a cell.

A mesoscopic numerical study of shear flow effects on asphaltene self-assembly behavior in organic solvents

2020 ◽  
Vol 22 (36) ◽  
pp. 20758-20770
Author(s):  
Mohammad Ahmadi ◽  
Hassan Hassanzadeh ◽  
Jalal Abedi
Keyword(s):  
Shear Flow ◽  
Organic Solvents ◽  
Self Assembly ◽  
Brownian Dynamics ◽  
Numerical Study ◽  
The Self ◽  
Dynamics Simulation ◽  
Brownian Dynamics Simulation ◽  
Assembly Behavior ◽  
Flow Effects

We employ the Brownian dynamics simulation to examine the shear flow effects on the self-assembly behavior of asphaltenes.

Capture, Deformation, Rolling and Detachment of a Cell on an Adhesive Surface in a Shear Flow

2008 ◽  
Author(s):  
Vijay Pappu ◽  
Prosenjit Bagchi
Keyword(s):  
Shear Flow ◽  
Bond Strength ◽  
Three Dimensional ◽  
Navier Stokes ◽  
Adherent Cell ◽  
Membrane Mechanics ◽  
Flow Solver ◽  
Front Tracking Method ◽  
Adhesive Surface ◽  
Computational Modeling And Simulation

Three-dimensional computational modeling and simulation using front tracking method are presented on the motion of a deformable cell over an adhesive surface in a shear flow. The numerical method couples a Navier-Stokes flow solver with cell membrane mechanics, and a Monte Carlo simulation to capture stochastic formation and breakage of receptor/ligand bonds. The entire range of events during cell adhesion, namely, initial arrest of a free-flowing cell, slow rolling of an adherent cell, and detachment off the surface is simulated. Simulations are conducted to signify the role of hydrodynamic lift force that exists for a deformable particle in a wall-bounded flow. Three sets of numerical experiments are presented. In the first set, we consider the initial arrest of the cell, and show that the time needed for the cell to arrest increases with increasing Ca, but rapidly drops and saturates for higher bond strength. In the second set, we consider quasi-steady rolling motion of the cell, and predict the experimentally observed “stop and go” motion of the rolling leukocytes which is characterized by intermittent pauses and sudden jumps in cell velocity. In the third set we consider the detachment of the cell from the surface upon breakage of bonds. The bond strength needed to prevent the detachment of an adherent cell is computed and shown to be maximum for an intermediate Ca.

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