scholarly journals The effect of hemicylindrical disruptors on the cell free layer thickness in animal blood flows inside microchannels

2020 ◽  
Vol 1 ◽  
Author(s):  
Duarte Dias ◽  
Duarte Sampaio ◽  
Goncalo Silva ◽  
Viriato Semiao
Keyword(s):  
Oxygen Transport ◽  
Free Layer ◽  
Low Velocity ◽  
Animal Blood ◽  
Narrow Channels ◽  
Blood Flows ◽  
Dimensional Measure ◽  
The Cost ◽  
Surrogate Systems ◽  
Cell Free Layer

Abstract Blood-side resistance to oxygen transport in extracorporeal membrane blood oxygenators (MBO) depends on fluid mechanics governing the laminar flow in very narrow channels, particularly the hemodynamics controlling the cell free layer (CFL) built-up at solid/blood interfaces. The CFL thickness constitutes a barrier to oxygen transport from the membrane towards the erythrocytes. Interposing hemicylindrical CFL disruptors in animal blood flows inside rectangular microchannels, surrogate systems of MBO mimicking their hemodynamics, proved to be effective in reducing (ca. 20%) such thickness (desirable for MBO to increase oxygen transport rates to the erythrocytes). The blockage ratio (non-dimensional measure of the disruptor penetration into the flow) increase is also effective in reducing CFL thickness (ca. 10–20%), but at the cost of risking clot formation (undesirable for MBO) for disruptors with penetration lengths larger than their radius, due to large residence times of erythrocytes inside a low-velocity CFL formed at the disruptor/wall edge.

scholarly journals Effects of erythrocyte deformability and aggregation on the cell free layer and apparent viscosity of microscopic blood flows

2009 ◽  
Vol 77 (3) ◽  
pp. 265-272 ◽  
Author(s):  
Junfeng Zhang ◽  
Paul C. Johnson ◽  
Aleksander S. Popel
Keyword(s):  
Apparent Viscosity ◽  
Erythrocyte Deformability ◽  
Free Layer ◽  
Blood Flows ◽  
Cell Free Layer

scholarly journals Emergent cell-free layer asymmetry and biased haematocrit partition in a biomimetic vascular network of successive bifurcations

Soft Matter ◽  
2021 ◽  
Author(s):  
Qi Zhou ◽  
Joana Fidalgo ◽  
Miguel Bernabeu ◽  
Mónica S.N. Oliveira ◽  
Timm Krüger
Keyword(s):  
Red Blood Cells ◽  
Human Body ◽  
Blood Cells ◽  
Soft Matter ◽  
Vascular Network ◽  
Free Layer ◽  
Cell Free Layer

Blood is a vital soft matter, and its normal circulation in the human body relies on the distribution of red blood cells (RBCs) at successive bifurcations. Understanding how RBCs are...

scholarly journals Effect of Cell-Free Layer Variation on Arteriolar Wall Shear Stress

2010 ◽  
Vol 39 (1) ◽  
pp. 359-366 ◽  
Author(s):  
Bumseok Namgung ◽  
Peng Kai Ong ◽  
Paul C. Johnson ◽  
Sangho Kim
Keyword(s):  
Shear Stress ◽  
Wall Shear Stress ◽  
Free Layer ◽  
Arteriolar Wall ◽  
Wall Shear ◽  
Cell Free Layer

scholarly journals Visualization and Quantification of the Cell-free Layer in Arterioles of the Rat Cremaster Muscle

10.3791/54550 ◽  
2016 ◽  
Author(s):  
Yan Cheng Ng ◽  
Liam K. Fisher ◽  
Veena Salim ◽  
Sangho Kim ◽  
Bumseok Namgung
Keyword(s):  
Cremaster Muscle ◽  
Free Layer ◽  
Cell Free Layer

Quantitative evaluation of flow dynamics of erythrocytes in microvessels: influence of erythrocyte aggregation

1995 ◽  
Vol 268 (5) ◽  
pp. H1959-H1965 ◽  
Author(s):  
M. Soutani ◽  
Y. Suzuki ◽  
N. Tateishi ◽  
N. Maeda
Keyword(s):  
Flow Resistance ◽  
Circulatory System ◽  
Flow Dynamics ◽  
Erythrocyte Aggregation ◽  
Intensity Change ◽  
Image Analyzer ◽  
Free Layer ◽  
High Shear Rates ◽  
Suspension Viscosity ◽  
Cell Free Layer

Effects of erythrocyte aggregation on the flow dynamics of erythrocytes in microvessels were examined quantitatively by perfusing human erythrocytes suspended in isotonic medium containing various concentrations of dextran (70,400 avg mol wt, Dx-70) into a part of the microvascular bed isolated from rabbit mesentery. Thickness of the marginal cell-free layer was measured with an image analyzer, total flow resistance was determined on the basis of the perfusion pressure-volume flow relationship, and homogeneity of erythrocyte flow was evaluated by the power spectrum obtained by the fast Fourier transform of the light intensity change monitored on single microvessels. With increasing dextran concentration, suspension viscosity of erythrocytes at high shear rates increased linearly and thickness of the cell-free layer increased in a sigmoidal fashion. Flow resistance increased relatively little over the range of dextran concentrations in which the cell-free layer increased most rapidly. Furthermore, the flow pattern of erythrocytes in microvessels became inhomogeneous. In conclusion, the present study shows that Dx-70-induced erythrocyte aggregation results in increased flow resistance in the circulatory system, even through the widening of the cell-free layer tends to reduce the resistance and also results in inhomogeneous flow of erythrocytes in microvessels.

scholarly journals Effects of cell‐free layer width and its variability on wall shear stress in arterioles

2009 ◽  
Vol 23 (S1) ◽  
Author(s):  
BumSeok Namgung ◽  
Peng Kai Ong ◽  
Paul C Johnson ◽  
Sangho Kim
Keyword(s):  
Shear Stress ◽  
Wall Shear Stress ◽  
Free Layer ◽  
Layer Width ◽  
Wall Shear ◽  
Cell Free Layer

Integration of cardiovascular regulation by the blood/endothelium cell-free layer

2011 ◽  
Vol 3 (4) ◽  
pp. 458-470 ◽  
Author(s):  
C. Makena Hightower ◽  
Beatriz Y. Salazar Vázquez ◽  
Sung Woo Park ◽  
Krishna Sriram ◽  
Judith Martini ◽  
...  
Keyword(s):  
Cardiovascular Regulation ◽  
Free Layer ◽  
Cell Free Layer

Modal Methodology for the Simulation and Optimisation of the Free-Layer Damping Treatment of a Car Body

2006 ◽  
Author(s):  
Marco Danti ◽  
Davide Vige` ◽  
Guido Vincent Nierop
Keyword(s):  
Weight Reduction ◽  
Design Space ◽  
Computation Time ◽  
Software Tool ◽  
Automotive Applications ◽  
Free Layer ◽  
Acoustic Performance ◽  
Damping Material ◽  
The Cost ◽  
Material Layout

The cost and weight reduction requirements in automotive applications are very important targets in the design of a new car. For this reason all the components of the vehicle have to be optimised, and the design of the damping material layout has to be deeply analysed in order to have a good NVH performance with the minimum of weight and cost. A tool for the optimisation of the damping material layout has been implemented and tested; the need to explore the entire design space with a big number of variables suggested the use of a genetic multi-objective algorithm for the optimisation. These algorithms require a large number of calculations and the solution of the complete NVH model would be too expensive in terms of computation time. For this reason, a new software tool has been developed based on the simulation of the damping material treatments by means of an auxiliary mass and stiffness matrix to be added to the baseline modal base; using this procedure the required time for the simulation of each damping material layout configuration is reduced to a few minutes, allowing to exploit the genetic algorithm capability to efficiently explore the design space. As a result, some configurations with an important weight reduction or a much better acoustic performance have been found. This method has been verified on a simple Aluminium box in order to verify all the assumptions and to test the effectiveness in predicting the vibration levels of plates with free layer damping added to it.

Effects of hematocrit variations on regional hemodynamics and oxygen transport in the dog

1980 ◽  
Vol 238 (4) ◽  
pp. H545-H522 ◽  
Author(s):  
F. C. Fan ◽  
R. Y. Chen ◽  
G. B. Schuessler ◽  
S. Chien
Keyword(s):  
Blood Flow ◽  
Cardiac Output ◽  
Blood Vessels ◽  
Oxygen Transport ◽  
Oxygen Supply ◽  
Blood Flows ◽  
Regional Hemodynamics ◽  
Regional Blood Flows ◽  
Splenic Vessels ◽  
The Brain

The responses of alterations in regional hemodynamics and oxygen transport rate to hematocrit (Hct) were studied in 20 pentobarbitalized dogs. Hemodilution was carried out by isovolemic exchange with plasma in 12 dogs and the hemoconcentration with packed cells in 8 dogs. The cardiac output and regional blood flows were determined with the microsphere technique. In hemodilution, the increases of blood flow to the myocardium and the brain were out of proportion to the increase of cardiac output; the oxygen supply to the myocardium remained unchanged while that to the brain decreased only slightly. In hemoconcentration, vasodilation occurred in the myocardium and the brain to maintain constant oxygen supply. Splenic vessels had marked vasoconstriction with Hct alteration in either direction. Blood vessels in the liver, intestine, and kidney responded with a milder vasoconstriction and maintained a constant oxygen supply between Hct of 30-55%. Therefore, during Hct alteration, redistribution of blood flow to myocardium and brain occurred. The optimal Hct range for constant oxygen supply was different among various organs.

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