The influence of oxygen concentration on the rheological properties and flow of whole human blood

Valant, A. Zupančič; Žiberna, Lovro; Papaharilaou, Yannis; Georgiou, Georgios C.

doi:10.1007/s00397-016-0967-y

Cited by 11 publications

(9 citation statements)

References 46 publications

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“…13 The viscosity of normal human blood, i.e., blood with a hematocrit value of about 42%-47%, at steady-state exhibits three distinct regions: a lower Newtonian region (reaching the low-rate viscosity, η 0 ), an upper Newtonian region (reaching the high-rate viscosity, η∞), and the intermediate region where the viscosity is decreasing with increasing shear rate, i.e., the blood is shear thinning. 9,14,15 This non-Newtonian behavior of blood is attributed to the aggregation of RBCs at lower shear rates, while as the shear rate increases, the RBC deformability becomes more and more influential and eventually predominant after about 10 s −1 . 16,17 Both factors, aggregability and deformability, affect blood rheology under different conditions.…”

Section: Introductionmentioning

confidence: 99%

A constitutive hemorheological model addressing both the deformability and aggregation of red blood cells

Stephanou

2020

Physics of Fluids

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Red blood cells (RBCs) in physiological conditions are capable of deforming and aggregating. However, both deformation and aggregation are seldom considered together when modeling the rheological behavior of blood. This is particularly important since each mechanism is dominant under specific conditions. To address this void, we herein propose a new model that accounts for the deformability of red blood cells, by modeling them as deformed droplets with a constant volume, and of their aggregation, by properly characterizing the network formed by red blood cells under small shear rates. To derive the model, we employ non-equilibrium thermodynamics that allows us to consistently couple the two mechanisms and guarantees model admissibility with the thermodynamic laws. Relative to our previous model, which addresses the rheological behavior of non-aggregating deformable red blood cells, one additional structural variable, λ, to properly characterize the network formed by RBCs, and another additional parameter, ε, that quantifies the relative importance between the regeneration/buildup and flow-induced breakup of the network, are considered here. The new model predicts a yield shear stress, in accord with experimental data, but also predicts non-vanishing yield normal stresses. Although no rheological measurements of yield normal stresses of blood have been reported in the literature, the recent measurement of yield normal stresses of other yield stress fluids indicates their potential existence in blood as well. We show that the new model is in complete accord with the experimental rheological behavior of normal blood in both steady-state and transient (step-change in shear-rate) simple shear.

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Section: Introductionmentioning

confidence: 99%

A constitutive hemorheological model addressing both the deformability and aggregation of red blood cells

Stephanou

2020

Physics of Fluids

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“…When considering the filtering of rheologically complex fluids, the extra stress tensor is no longer a linear, isotropic function of the components of the velocity gradients, but it requires more complicated constitutive equations. For example, blood exhibits non-Newtonian properties, i.e., shear-thinning, viscoelasticity, thixotropy and yield stress [18]. As a first attempt to study the performance of a pore for non-Newtonian liquids, we consider a simple power-law model based on the Ostwald-de Waele constitutive equation [10], which incorporates shear-thickening and shear-thinning effects.…”

Section: Constantinou Et Almentioning

confidence: 99%

“…Although its main limitation is that it predicts an unbounded stress in regions where the shear-rate is zero, this model is commonly invoked as a starting point for more complex models, e.g. the Herschel-Bulkley model [18].…”

Section: Constantinou Et Almentioning

confidence: 99%

Optimizing the performance of a conical ceramic membrane

Constantinou

Cracco

Danieli

et al. 2021

Preprint

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Smart Separations Limited (SSL) is a UK-based start-up who have developed a ceramic membrane with micron-sized conical pores distinct to the cylindrical pores typically used for filtration. This new technology has the potential to be highly beneficial to many applications. However to realize its potential, a comprehensive analysis of the performance and efficiency of the membrane is vital. We use mathematical modelling to explore and quantify the behaviour and performance of the membrane and its link to the underlying pore structure. We derive a reduced model based on the slenderness of the membrane pores that allows us to predict the flux through the membrane, the optimal pore shape that maximizes the amount of contaminant that is trapped. A full 2D numerical framework allows us to study the flow structure within the pores and the effect of changing the angle of the flow of contaminants as it reaches the membrane. Finally, a probabilistic model based on expectation values provides an analytic prediction for the flux decline with time due to membrane blocking. The outcomes of this work provide a first step to providing the key modelling insight that will allow SSL to take this new technology to market.

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“…In this study, we kept the non-Newtonian property for blood flow modeling to stay closer to reality. We considered the Herschal-Bulkley condition, which defines viscosity properties as in [51]:…”

Section: Arterial Model Reconstruction and Computational Mesh Generationmentioning

confidence: 99%

A Spatiotemporal exploration and 3D modeling of blood flow in healthy carotid artery bifurcation from two modalities: Ultrasound-Doppler and phase contrast MRI

Debbich

Abdallah

Maatouk

et al. 2020

Computers in Biology and Medicine

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In the present study, we investigated the velocity profile over the carotid bifurcation in ten healthy volunteers by combining velocity measurements from two imaging modalities (PC-MRI and US-Doppler) and hemodynamic modeling in order to determine the optimal combination for the most realistic velocity estimation. The workflow includes data acquisition, velocity profile extraction at three sites (CCA, ECA and ICA), the arterial geometrical model reconstruction, a mesh generation and a rheological modeling. The results showed that US-Doppler measurements yielded higher velocity values as compared to PC-MRI (about 26% shift in CCA, 52% in ECA and 53% in ICA). This implies higher simulated velocities based on US-Doppler inlet as compared to simulated velocities based on PC-MRI inlet. Overall, PC-MRI inlet based simulations are closer to measurements than US-Doppler inlet based simulations. Moreover, the measured velocities showed that blood flow keeps a parabolic sectional profile distal from CCA, ECA and ICA, while being quite disturbed in the carotid sinus with a significant decrease in magnitude making this site very prone to atherosclerosis.

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The influence of oxygen concentration on the rheological properties and flow of whole human blood

Cited by 11 publications

References 46 publications

A constitutive hemorheological model addressing both the deformability and aggregation of red blood cells

A constitutive hemorheological model addressing both the deformability and aggregation of red blood cells

Optimizing the performance of a conical ceramic membrane

A Spatiotemporal exploration and 3D modeling of blood flow in healthy carotid artery bifurcation from two modalities: Ultrasound-Doppler and phase contrast MRI

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