scholarly journals Shear rate specific blood viscosity and shear stress of carotid artery duplex ultrasonography in patients with lacunar infarction

BMC Neurology ◽  
2013 ◽  
Vol 13 (1) ◽  
Author(s):  
Seul-Ki Jeong ◽  
Robert S Rosenson
Keyword(s):  
Shear Stress ◽  
Shear Rate ◽  
Carotid Artery ◽  
Blood Viscosity ◽  
Lacunar Infarction ◽  
Duplex Ultrasonography

scholarly journals Hemodynamic Changes in the Carotid Artery after Infusion of Normal Saline Using Computational Fluid Dynamics

Diagnostics ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 473
Author(s):  
Ui Yun Lee ◽  
Chul In Kim ◽  
Gyung Ho Chung ◽  
Jinmu Jung ◽  
Hyo Sung Kwak
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Shear Stress ◽  
Shear Rate ◽  
Carotid Artery ◽  
Normal Saline ◽  
Blood Viscosity ◽  
Internal Carotid ◽  
Hemodynamic Changes ◽  
Before And After

Purpose: To study the effect of the infusion of normal saline on hemodynamic changes in healthy volunteers using computational fluid dynamics (CFD) simulation. Methods: Eight healthy subjects participated and 16 carotid arteries were used for the CFD analysis. A one-liter intravenous infusion of normal saline was applied to the participants to observe the hemodynamic variations. Blood viscosity was measured before and after the injection of normal saline to apply the blood properties on the CFD modeling. Blood viscosity, shear rate, and wall shear stress were visually and quantitatively shown for the comparison between before and after the infusion of normal saline. Statistical analyses were performed to confirm the difference between the before and after groups. Results: After the infusion of normal saline, decreased blood viscosity was observed in the whole carotid artery. At the internal carotid artery, the recirculation zone with low intensity was found after the injection of normal saline. Increased shear rate and reduced wall shear stress was observed at the carotid bifurcation and internal carotid artery. The hemodynamic differences between before and after groups were statistically significant. Conclusions: The infusion of normal saline affected not only the overall changes of blood flow in the carotid artery but also the decrease of blood viscosity.

scholarly journals Endothelial shear rate, local and regional vascular stiffness in patients in different stages of atherogenesis

2016 ◽  
Vol 15 (3) ◽  
pp. 50-56
Author(s):  
V. V. Genkel ◽  
A. O. Salachenko ◽  
O. A. Alekseeva ◽  
I. I. Shaposhnik
Keyword(s):  
Shear Stress ◽  
Shear Rate ◽  
Carotid Artery ◽  
Common Carotid Artery ◽  
Carotid Arteries ◽  
Vascular Stiffness ◽  
Stiffness Index ◽  
The Common ◽  
Relationship Of ◽  
The Relationship

Introduction and purpose. Endothelial cells are subjected to biomechanical stress produced by the bloodstream and tunica media of the vessel. Vascular stiffness and endothelial shear stress have cooperative effects on the endothelial structure and function. However, the relationship of shear stress and arterial stiffness is still poorly understood. The purpose of the study was to assess the relationship of endothelial shear rate and both local and regional vascular stiffness in patients at different stages of the development of atherosclerosis. Methods. The study included 60 patients, 33 men and 27 women. The average age of patients was 54.8±11.7 years. Regional arterial stiffness was assessed by measurement of the pulse wave velocity in the arteries of elastic and muscular types. Local stiffness of the carotid arteries was characterized by Peterson elastic modulus, Young's modulus, stiffness index β, the deformation of the common carotid artery. Endothelial shear rate was measured at the site of the common carotid artery. Results. Average values of carotid endothelial shear rate were equal to 433±127 s-1. Reduced endothelial shear rate in the carotid arteries was associated with an increased Peterson modulus (r = -0.289; p = 0.025) and the stiffness index β (r = -0.280; p = 0.037), and moreover - with decreasing vascular distensibility (r = 0.288; p = 0.026) and deformation (r = 0.296; p = 0.024). Assessment of the relationship between endothelial shear rate and regional vascular stiffness showed weak statistically significant negative correlation of shear rate and PWVcf (r = -0.367; p = 0.014). Conclusion. In study subjects endothelial shear rate reduction in the area of the common carotid artery was associated with an increased Peterson modulus, stiffness index β, decreasing deformation of carotid arteries and increase in aortic stiffness.

scholarly journals Rheology of embryonic avian blood

2011 ◽  
Vol 301 (6) ◽  
pp. H2473-H2481 ◽  
Author(s):  
Sarah Al-Roubaie ◽  
Espen D. Jahnsen ◽  
Masud Mohammed ◽  
Caitlin Henderson-Toth ◽  
Elizabeth A. V. Jones
Keyword(s):  
Shear Stress ◽  
Shear Rate ◽  
Cardiovascular System ◽  
Blood Viscosity ◽  
Apparent Viscosity ◽  
Developmental Stages ◽  
Shear Rates ◽  
Stage Of Development ◽  
Avian Blood ◽  
Newtonian Behavior

Shear stress, a mechanical force created by blood flow, is known to affect the developing cardiovascular system. Shear stress is a function of both shear rate and viscosity. While established techniques for measuring shear rate in embryos have been developed, the viscosity of embryonic blood has never been known but always assumed to be like adult blood. Blood is a non-Newtonian fluid, where the relationship between shear rate and shear stress is nonlinear. In this work, we analyzed the non-Newtonian behavior of embryonic chicken blood using a microviscometer and present the apparent viscosity at different hematocrits, different shear rates, and at different stages during development from 4 days (Hamburger-Hamilton stage 22) to 8 days (about Hamburger-Hamilton stage 34) of incubation. We chose the chicken embryo since it has become a common animal model for studying hemodynamics in the developing cardiovascular system. We found that the hematocrit increases with the stage of development. The viscosity of embryonic avian blood in all developmental stages studied was shear rate dependent and behaved in a non-Newtonian manner similar to that of adult blood. The range of shear rates and hematocrits at which non-Newtonian behavior was observed is, however, outside the physiological range for the larger vessels of the embryo. Under low shear stress conditions, the spherical nucleated blood cells that make up embryonic blood formed into small aggregates of cells. We found that the apparent blood viscosity decreases at a given hematocrit during embryonic development, not due to changes in protein composition of the plasma but possibly due to the changes in cellular composition of embryonic blood. This decrease in apparent viscosity was only visible at high hematocrit. At physiological values of hematocrit, embryonic blood viscosity did not change significantly with the stage of development.

Reproducibility of shear rate and shear stress assessment by means of ultrasound in the common carotid artery of young human males and females

1997 ◽  
Vol 23 (4) ◽  
pp. 583-590 ◽  
Author(s):  
Steven K. Samijo ◽  
Jean M. Willigers ◽  
Peter J. Brands ◽  
Richard Barkhuysen ◽  
Robert S. Reneman ◽  
...  
Keyword(s):  
Shear Stress ◽  
Shear Rate ◽  
Carotid Artery ◽  
Common Carotid Artery ◽  
Stress Assessment ◽  
The Common ◽  
Males And Females

scholarly journals Shear stress depends on vascular territory: comparison between common carotid and brachial artery

2003 ◽  
Vol 94 (2) ◽  
pp. 485-489 ◽  
Author(s):  
Ruben Dammers ◽  
Frank Stifft ◽  
Jan H. M. Tordoir ◽  
Jeroen M. M. Hameleers ◽  
Arnold P. G. Hoeks ◽  
...  
Keyword(s):  
Shear Stress ◽  
Shear Rate ◽  
Brachial Artery ◽  
Blood Viscosity ◽  
Whole Blood ◽  
Vascular System ◽  
Vascular Territory ◽  
Whole Blood Viscosity ◽  
Estimation System

Shear stress (SS) is thought to be constant throughout the vascular system. Evidence for this supposition is scarce, however. To verify this hypothesis in vivo, we assessed common carotid (CCA) and brachial artery (BA) peak and mean wall shear rate (SR) noninvasively in 10 healthy volunteers (23.7 ± 3.4 yr) with an ultrasound SR estimation system. SS was estimated from SR and calculated whole blood viscosity. SR was higher ( P < 0.05) in the CCA (mean: 359 ± 111 s−1; peak: 1,047 ± 345 s−1) than in the BA (mean: 95 ± 24 s−1; peak: 770 ± 170 s−1). Whole blood viscosity was higher in the BA than in the CCA (5.1 ± 0.7 vs. 3.3 ± 0.6 mPa · s; P < 0.001). Peak SS did not differ between the CCA and the BA, whereas mean SS was significantly higher in the CCA (1.15 ± 0.21 Pa) than in the BA (0.48 ± 0.15 Pa; P < 0.001). These results demonstrate that BA SS strongly deviates from CCA SS in vivo.

The Effects of KBT-3022, a New Anti-platelet Agent, on Hemorheological Properties in Guinea Pigs

1995 ◽  
Vol 73 (01) ◽  
pp. 118-121 ◽  
Author(s):  
Noriko Yamamoto ◽  
Koichi Yokota ◽  
Akira Yamashita ◽  
Minoru Oda
Keyword(s):  
Shear Stress ◽  
Blood Viscosity ◽  
Guinea Pigs ◽  
Direct Action ◽  
Plasma Viscosity ◽  
Fibrinogen Concentration ◽  
Anti Platelet Agent ◽  
Blood Filterability ◽  
2,3 Dpg ◽  
Rbc Deformability

SummaryUsing guinea pigs, a study was conducted on the effects of KBT-3022, a new anti-platelet agent, on hemorheological properties in various tests including blood filterability, blood viscosity, shear stress-induced red blood cell (RBC) deformability and contents of ATP and 2,3-diphosphoglycerate (2,3-DPG). Oral administration of KBT-3022 at 1 and 10 mg/kg significantly increased blood filterability, and significantly reduced blood viscosity at 10 mg/kg without changing the hematocrit, plasma fibrinogen concentration or plasma viscosity. KBT-3022 (10 mg/kg, p.o.) improved RBC deformability in response to shear stress, which was evoked by passing the blood through a thin tube. This dose of KBT-3022 also increased the contents of ATP and 2,3-DPG in RBC. These findings indicate that KBT-3022 may reduce blood viscosity as a sequel to improvement of RBC deformability through direct action on RBC. The increase in the intracellular levels of ATP and 2,3-DPG was considered to be involved in this improvement of hemorheological properties. These hemorheological effects of KBT-3022 appear to be promising for the treatment of patients with ischemic vascular disease.

Basic study on estimation method of wall shear stress in common carotid artery using blood flow imaging

2020 ◽  
Vol 59 (SK) ◽  
pp. SKKE16 ◽  
Author(s):  
Ryo Nagaoka ◽  
Kazuma Ishikawa ◽  
Michiya Mozumi ◽  
Magnus Cinthio ◽  
Hideyuki Hasegawa
Keyword(s):  
Blood Flow ◽  
Shear Stress ◽  
Carotid Artery ◽  
Wall Shear Stress ◽  
Common Carotid Artery ◽  
Estimation Method ◽  
Flow Imaging ◽  
Basic Study ◽  
Blood Flow Imaging ◽  
Wall Shear

scholarly journals Quantification of shear viscosity and wall slip velocity of highly concentrated suspensions with non-Newtonian matrices in pressure driven flows

2021 ◽  
Author(s):  
Patrick Wilms ◽  
Jan Wieringa ◽  
Theo Blijdenstein ◽  
Kees van Malssen ◽  
Reinhard Kohlus
Keyword(s):  
Shear Stress ◽  
Liquid Phase ◽  
Shear Rate ◽  
Shear Viscosity ◽  
Slip Velocity ◽  
Volume Fraction ◽  
Solid Volume Fraction ◽  
Wall Slip ◽  
Flow Index ◽  
Concentrated Suspensions

AbstractThe rheological characterization of concentrated suspensions is complicated by the heterogeneous nature of their flow. In this contribution, the shear viscosity and wall slip velocity are quantified for highly concentrated suspensions (solid volume fractions of 0.55–0.60, D4,3 ~ 5 µm). The shear viscosity was determined using a high-pressure capillary rheometer equipped with a 3D-printed die that has a grooved surface of the internal flow channel. The wall slip velocity was then calculated from the difference between the apparent shear rates through a rough and smooth die, at identical wall shear stress. The influence of liquid phase rheology on the wall slip velocity was investigated by using different thickeners, resulting in different degrees of shear rate dependency, i.e. the flow indices varied between 0.20 and 1.00. The wall slip velocity scaled with the flow index of the liquid phase at a solid volume fraction of 0.60 and showed increasingly large deviations with decreasing solid volume fraction. It is hypothesized that these deviations are related to shear-induced migration of solids and macromolecules due to the large shear stress and shear rate gradients.

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