Biorheology最新文献_第10页

Osteoarthritic synovial fluid and correlations with protein concentration. 骨关节炎滑液与蛋白浓度的关系。

IF 1.1 4区医学

Biorheology Pub Date : 2016-01-01 DOI: 10.3233/BIR-15086

A. Madkhali, Michael Chernos, S. Fakhraei, D. Grecov, E. Kwok

{"title":"Osteoarthritic synovial fluid and correlations with protein concentration.","authors":"A. Madkhali, Michael Chernos, S. Fakhraei, D. Grecov, E. Kwok","doi":"10.3233/BIR-15086","DOIUrl":"https://doi.org/10.3233/BIR-15086","url":null,"abstract":"BACKGROUND Osteoarthritis is a common, localized joint disease that causes pain, stiffness and reduced mobility. The effects of osteoarthritis on the extensional rheology of synovial fluid in the knees are not fully understood and consequently require further study. OBJECTIVE The purpose of this work is to study the extensional rheology of osteoarthritic synovial fluid and to investigate a possible correlation between synovial fluid protein concentration and extensional rheology. The study will also investigate possible correlations with the shear rheology. METHODS 21 osteoarthritic synovial fluid samples were studied under extensional flow with a capillary breakup extensional rheometer. Extensional rheological properties were correlated with protein concentration and with shear rheological properties measured in a prior study. Viscosupplement was also studied under extensional flow for comparison. RESULTS Extensional rheological properties were found to vary widely between samples, but in general were found to agree with previous studies. No statistically significant correlation was identified between extensional rheological properties and protein concentration. Positive correlations were identified between zero shear viscosity and terminal extensional viscosity (R-squared = 0.73), zero shear viscosity and extensional relaxation time (R-squared = 0.84), and shear relaxation time and extensional relaxation time (R-squared = 0.75). CONCLUSIONS Appropriate CaBER operating parameters for study of osteoarthritic synovial fluid were identified. No statistically significant correlation was found to exist between protein concentration and extensional rheological parameters. Positive correlations were identified between several shear and extensional rheological parameters. The reported values for extensional viscosity and relaxation times for synovial fluid were found to be within one order of magnitude with a recent study of post mortem synovial fluid.","PeriodicalId":9167,"journal":{"name":"Biorheology","volume":"53 3-4 1","pages":"123-136"},"PeriodicalIF":1.1,"publicationDate":"2016-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3233/BIR-15086","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69792848","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 4

Biphasic impairment of erythrocyte deformability in response to repeated, short duration exposures of supraphysiological, subhaemolytic shear stress. 红细胞变形能力的双相损伤响应于重复，短时间暴露的超生理，亚溶血剪切应力。

IF 1.1 4区医学

Biorheology Pub Date : 2016-01-01 DOI: 10.3233/BIR-15108

Antony P. McNamee, G. Tansley, S. Sabapathy, Michael J. Simmonds

{"title":"Biphasic impairment of erythrocyte deformability in response to repeated, short duration exposures of supraphysiological, subhaemolytic shear stress.","authors":"Antony P. McNamee, G. Tansley, S. Sabapathy, Michael J. Simmonds","doi":"10.3233/BIR-15108","DOIUrl":"https://doi.org/10.3233/BIR-15108","url":null,"abstract":"INTRODUCTION Despite current generation mechanical assist devices being designed to limit shear stresses and minimise damage to formed elements in blood, severe secondary complications suggestive of impaired rheological functioning are still observed. At present, the precise interactions between the magnitude-duration of shear stress exposure and the deformability of red blood cells (RBC) remain largely undescribed for repeated subhaemolytic shear stress duty-cycles of less than 15 s. Given that the time taken for blood to traverse mechanical devices (e.g., Bio Pump) typically ranges from 1.85-3.08 s, the present study examined the influence of repeated, short duration, supraphysiological shear stress exposure on RBC function. METHODS RBC were exposed to shear stress duty-cycles of 64 Pa × 3 s or 88 Pa × 2 s, for 10 repeated bouts, in an annular Couette shearing system and ektacytometer. Laser diffractometry was used to measure RBC deformability before and after application of each duty-cycle. Free haemoglobin concentration and RBC morphology was also examined following shear exposure to determine cell viability. RESULTS Initial exposure to shear stress duty-cycles decreased RBC deformability and increased RBC sensitivity to mechanical damage. Interestingly, the pattern of change in these variables reversed and returned to baseline values within two successive duty-cycle exposures. Significant improvements in RBC deformability were then observed by the 9th repeated exposure to 64 Pa × 3 s. CONCLUSIONS Repeat applications of short duration supraphysiological, subhaemolytic shear stress induces a biphasic RBC deformability response that appears to progressively improve initially impaired RBC populations.","PeriodicalId":9167,"journal":{"name":"Biorheology","volume":"53 3-4 1","pages":"137-149"},"PeriodicalIF":1.1,"publicationDate":"2016-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3233/BIR-15108","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69793230","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 20

Deformation and rupture of Dunaliella salina at high shear rates without the use of thickeners. 不使用增稠剂的盐杜氏藻在高剪切速率下的变形和破裂。

IF 1.1 4区医学

Biorheology Pub Date : 2016-01-01 DOI: 10.3233/BIR-15057

D. Kokkinos, H. Dakhil, A. Wierschem, H. Briesen, A. Braun

{"title":"Deformation and rupture of Dunaliella salina at high shear rates without the use of thickeners.","authors":"D. Kokkinos, H. Dakhil, A. Wierschem, H. Briesen, A. Braun","doi":"10.3233/BIR-15057","DOIUrl":"https://doi.org/10.3233/BIR-15057","url":null,"abstract":"BACKGROUND High-density cultures require operating below the critical threshold of shear stress, in order to avoid reducing the specific growth rate of the cells. When determining this threshold, direct inspection of the cells in flow provides insight into the conditions of shearing. OBJECTIVE Aim of this study was using a novel rheo-optical setup for the observation of cells in laminar shear flow and the determination of the critical shear stress required to damage them in their natural environment. METHODS Dunaliella salina cells were sheared and observed in flow for shear stresses of up to 90 Pa, at ambient temperature, without adding thickeners. The critical shear stress was determined by fitting a hydrodynamics-based criterion to the experimental data on the percentage of deformed cells after shearing. RESULTS Single cells, clusters and strings of cells were visible in shear flow. The strings formed at maximum shear stresses of 10 Pa or higher. Cells lost motility for maximum shear stresses higher than 15 Pa, and more than 80% of the cells were deformed at maximum shear stresses higher than 60 Pa. The estimated critical shear stress was 18 Pa. CONCLUSIONS Shear stresses higher than 18 Pa should be avoided when cultivating D. salina.","PeriodicalId":9167,"journal":{"name":"Biorheology","volume":"53 1 1","pages":"1-11"},"PeriodicalIF":1.1,"publicationDate":"2016-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3233/BIR-15057","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69792443","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 6

Role of fluid shear stress in regulating VWF structure, function and related blood disorders 流体剪切应力在调节VWF结构、功能和相关血液疾病中的作用

IF 1.1 4区医学

Biorheology Pub Date : 2015-11-19 DOI: 10.3233/BIR-15061

Shobhit Gogia, S. Neelamegham

{"title":"Role of fluid shear stress in regulating VWF structure, function and related blood disorders","authors":"Shobhit Gogia, S. Neelamegham","doi":"10.3233/BIR-15061","DOIUrl":"https://doi.org/10.3233/BIR-15061","url":null,"abstract":"Von Willebrand factor (VWF) is the largest glycoprotein in blood. It plays a crucial role in primary hemostasis via its binding interaction with platelet and endothelial cell surface receptors, other blood proteins and extra-cellular matrix components. This protein is found as a series of repeat units that are disulfide bonded to form multimeric structures. Once in blood, the protein multimer distribution is dynamically regulated by fluid shear stress which has two opposing effects: it promotes the aggregation or self-association of multiple VWF units, and it simultaneously reduces multimer size by facilitating the force-dependent cleavage of the protein by various proteases, most notably ADAMTS13 (a disintegrin and metalloprotease with thrombospondin type repeats, motif 1 type 13). In addition to these effects, fluid shear also controls the solution and substrate-immobilized structure of VWF, the nature of contact between blood platelets and substrates, and the biomechanics of the GpIbα–VWF bond. These features together regulate different physiological and pathological processes including normal hemostasis, arterial and venous thrombosis, von Willebrand disease, thrombotic thrombocytopenic purpura and acquired von Willebrand syndrome. This article discusses current knowledge of VWF structure–function relationships with emphasis on the effects of hydrodynamic shear, including rapid methods to estimate the nature and magnitude of these forces in selected conditions. It shows that observations made by many investigators using solution and substrate-based shearing devices can be reconciled upon considering the physical size of VWF and the applied mechanical force in these different geometries.","PeriodicalId":9167,"journal":{"name":"Biorheology","volume":"52 1","pages":"319 - 335"},"PeriodicalIF":1.1,"publicationDate":"2015-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3233/BIR-15061","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69792574","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 78

15th International Congress of Biorheology and 8th International Conference on Clinical Hemorheology, Seoul, Korea, May 24-28, 2015: Scientific Program. 第15届国际生物流变学大会和第8届国际临床血液流变学会议，韩国首尔，2015年5月24-28日:科学计划。

IF 1.1 4区医学

Biorheology Pub Date : 2015-01-01 DOI: 10.3233/BIR-150669

引用次数: 0

Hemodynamics in stenotic vessels of small diameter under steady state conditions: Effect of viscoelasticity and migration of red blood cells. 稳态条件下小直径狭窄血管的血流动力学:红细胞粘弹性和迁移的影响。

IF 1.1 4区医学

Biorheology Pub Date : 2015-01-01 DOI: 10.3233/BIR-14033

Yannis Dimakopoulos, George Kelesidis, Sophia Tsouka, Georgios C Georgiou, John Tsamopoulos

{"title":"Hemodynamics in stenotic vessels of small diameter under steady state conditions: Effect of viscoelasticity and migration of red blood cells.","authors":"Yannis Dimakopoulos, George Kelesidis, Sophia Tsouka, Georgios C Georgiou, John Tsamopoulos","doi":"10.3233/BIR-14033","DOIUrl":"https://doi.org/10.3233/BIR-14033","url":null,"abstract":"BACKGROUND In microcirculation, the non-Newtonian behavior of blood and the complexity of the microvessel network are responsible for the high flow resistance and the large reduction of the blood pressure. Red blood cell aggregation along with inward radial migration are two significant mechanisms determining the former. Yet, their impact on hemodynamics in non-straight vessels is not well understood. OBJECTIVE In this study, the steady state blood flow in stenotic rigid vessels is examined, employing a sophisticated non-homogeneous constitutive law. The effect of red blood cells migration on the hydrodynamics is quantified and the constitutive model's accuracy is evaluated. METHODS A numerical algorithm based on the two-dimensional mixed finite element method and the EVSS/SUPG technique for a stable discretization of the mass and momentum conservation equations in addition to the constitutive model is employed. RESULTS The numerical simulations show that a cell-depleted layer develops along the vessel wall with an almost constant thickness for slow flow conditions. This causes the reduction of the drag force and the increase of the pressure gradient as the constriction ratio decreases. CONCLUSIONS Viscoelastic effects in blood flow were found to be responsible for steeper decreases of tube and discharge hematocrits as decreasing function of constriction ratio.","PeriodicalId":9167,"journal":{"name":"Biorheology","volume":"52 3","pages":"183-210"},"PeriodicalIF":1.1,"publicationDate":"2015-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3233/BIR-14033","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"34102882","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 29

Hemodynamics of the renal artery ostia with implications for their structural development and efficiency of flow. 肾动脉口的血流动力学及其结构发育和血流效率的影响。

IF 1.1 4区医学

Biorheology Pub Date : 2015-01-01 DOI: 10.3233/BIR-15069

W. McIntosh, M. Ozturk, L. A. Down, D. Papavassiliou, E. O’Rear

{"title":"Hemodynamics of the renal artery ostia with implications for their structural development and efficiency of flow.","authors":"W. McIntosh, M. Ozturk, L. A. Down, D. Papavassiliou, E. O’Rear","doi":"10.3233/BIR-15069","DOIUrl":"https://doi.org/10.3233/BIR-15069","url":null,"abstract":"BACKGROUND Energy losses at tube or blood vessel orifices depend on the extent of flare as measured by the dimensionless ratio of the fillet radius of curvature to diameter (r/D). OBJECTIVE The goal of this study was to assess the effect of ostial fillet radii on energy losses at the aorta-renal artery junctions since as much as a quarter of cardiac output passes through the kidneys. METHOD Pressure loss coefficients K for the renal artery ostia as a function of r/D have been determined for representative anatomical variants using finite volume simulations. Estimates of fillet radii in humans from image analysis were employed in simulations for comparison of loss coefficients. RESULTS Values for K drop 45% as r/D increases over the range 0-1.3. Image analysis indicates that the ostia are not symmetric in humans with (r/D)superior much larger than (r/D)inferior. Simulations show the loss coefficient depends almost entirely on the superior fillet radius. CONCLUSIONS Superior fillet radii for both renal arteries are similar to the optimal value to reduce energy losses while the inferior radii are not. Ostial asymmetry may have been induced by higher levels of shear stress present on the superior portion of a developing symmetric ostium of small r/D.","PeriodicalId":9167,"journal":{"name":"Biorheology","volume":"52 4 1","pages":"257-68"},"PeriodicalIF":1.1,"publicationDate":"2015-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3233/BIR-15069","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69792694","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Using cell monolayer rheology to probe average single cell mechanical properties. 利用细胞单层流变学研究平均单细胞力学性能。

IF 1.1 4区医学

Biorheology Pub Date : 2015-01-01 DOI: 10.3233/BIR-15070

M. Sander, J. Flesch, A. Ott

引用次数: 6

Influence of plaque stiffness on deformation and blood flow patterns in models of stenosis. 斑块硬度对狭窄模型中变形和血流模式的影响。

IF 1.1 4区医学

Biorheology Pub Date : 2015-01-01 DOI: 10.3233/BIR-14016

Yasutomo Shimizu, Makoto Ohta

{"title":"Influence of plaque stiffness on deformation and blood flow patterns in models of stenosis.","authors":"Yasutomo Shimizu, Makoto Ohta","doi":"10.3233/BIR-14016","DOIUrl":"https://doi.org/10.3233/BIR-14016","url":null,"abstract":"Background: Blood flow in stenotic vessels strongly influences the progression of vascular diseases. Plaques in stenotic blood vessels vary in stiffness, which influences plaque behavior and deformation by pressure and flow. Concurrent changes in plaque geometry can, in turn, affect blood flow conditions. Thus, simultaneous studies of blood flow and plaque deformation are needed to fully understand these interactions.Objectives: This study aims to identify the change of flow conditions attendant to plaque deformation in a model stenotic vessel.Methods: Three plaques of differing stiffness were constructed on a vessel wall using poly (vinyl alcohol) hydrogels (PVA-H) with defined stiffness to facilitate simultaneous observations of blood flow and plaque deformation. Flow patterns were observed using particle image velocimetry (PIV).Results: Decreases in Reynolds number (Re) with increased plaque deformation suggest that velocity decrease is more critical to establishment of the flow pattern than expansion of the model lumen. Upon exiting the stenosis, the location of the flow reattachment point, shifted further downstream in all models as plaque stiffness decreased and depended on the increase in upstream pressure.Conclusions: These results suggest that in addition to luminal area, plaque stiffness should be considered as a measure of the severity of the pathology.","PeriodicalId":9167,"journal":{"name":"Biorheology","volume":"52 3","pages":"171-82"},"PeriodicalIF":1.1,"publicationDate":"2015-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3233/BIR-14016","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"34036705","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 10

Numerical simulation of dielectrophoretic separation of live/dead cells using a three-dimensional nonuniform AC electric field in micro-fabricated devices. 微加工器件中三维非均匀交流电场对活/死细胞介电泳分离的数值模拟。

IF 1.1 4区医学

Biorheology Pub Date : 2015-01-01 DOI: 10.3233/BIR-14039

Shigeru Tada

{"title":"Numerical simulation of dielectrophoretic separation of live/dead cells using a three-dimensional nonuniform AC electric field in micro-fabricated devices.","authors":"Shigeru Tada","doi":"10.3233/BIR-14039","DOIUrl":"https://doi.org/10.3233/BIR-14039","url":null,"abstract":"Background: The analysis of cell separation has many important biological and medical applications. Dielectrophoresis (DEP) is one of the most effective and widely used techniques for separating and identifying biological species.Objective: In the present study, a DEP flow channel, a device that exploits the differences in the dielectric properties of cells in cell separation, was numerically simulated and its cell-separation performance examined.Methods: The samples of cells used in the simulation were modeled as human leukocyte (B cell) live and dead cells. The cell-separation analysis was carried out for a flow channel equipped with a planar electrode on the channel's top face and a pair of interdigitated counter electrodes on the bottom. This yielded a three-dimensional (3D) nonuniform AC electric field in the entire space of the flow channel.Results: To investigate the optimal separation conditions for mixtures of live and dead cells, the strength of the applied electric field was varied. With appropriately selected conditions, the device was predicted to be very effective at separating dead cells from live cells.Conclusions: The major advantage of the proposed method is that a large volume of sample can be processed rapidly because of a large spacing of the channel height.","PeriodicalId":9167,"journal":{"name":"Biorheology","volume":"52 3","pages":"211-24"},"PeriodicalIF":1.1,"publicationDate":"2015-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3233/BIR-14039","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"34103376","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 6