scholarly journals Safety of Five Tuina Manipulations in Rats with Deep Vein Thrombosis

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Ying Zhou ◽  
Yumo Zhang ◽  
Xiaoyan Zhang ◽  
Zhuo Chen ◽  
Jian Dong ◽  
...  
Keyword(s):  
Deep Vein Thrombosis ◽  
Shear Rate ◽  
Strain Rate ◽  
Rate Ratio ◽  
Plasma Viscosity ◽  
High Shear Rate ◽  
High Shear ◽  
Vein Thrombosis ◽  
Deep Vein ◽  
Low Shear

Objective. To study the effects of five tuina manipulations in rats with deep vein thrombosis (DVT) and to explore how to safely perform tuina in the treatment of thrombotic diseases. Methods. Seventy-two male Sprague-Dawley (SD) rats were randomly divided into the model, pointing manipulation, plucking manipulation, kneading manipulation, pushing manipulation, and pulling manipulation groups (n = 12). DVT model was established by incomplete ligation. The tuina intervention was started on the next day after modeling and applied once a day 10 times by the manipulation simulators. On the 3rd and 10th days after intervention, respectively, the effects of tuina on thrombosis were evaluated based on thrombus elasticity, blood coagulation, fibrinolytic function and blood rheology with the ultrasound elastography, four coagulation tests, enzyme linked immunosorbent assay (ELISA), and hemorheology tests. Results. In the pointing manipulation group, the strain rate ratio, 6-ketoprostaglandin F1α (6-Keto-PGF1α), and high shear rate were decreased, and the thromboxane B2 (TXB2) content was increased ( P < 0.05 ). In the plucking manipulation group, the D-dimer and 6-Keto-PGF1α contents were increased, prothrombin time (PT) was shortened, and activated partial thromboplastin time (APTT) was activated, and the high shear rate and plasma viscosity were decreased ( P < 0.05 ). In the kneading manipulation group, APTT was shortened, and 6-Keto-PGF1α, high shear rate, and plasma viscosity were decreased ( P < 0.05 ). In the pushing manipulation group, the strain rate ratio, low shear rate, and high shear rate were all decreased ( P < 0.05 ). In the pulling manipulation group, both the strain rate ratio and the low shear rate were decreased ( P < 0.05 ). The 6-Keto-PGF1α changes on the 3rd and 10th days after intervention were opposite in the pushing manipulation group and the pulling manipulation group ( P < 0.05 ). Conclusion. The pointing, pushing, and pulling manipulations seem to be safe in the early period of thrombosis, but the risk is likely to be elevated as the treatment course of intervention increases. The plucking and kneading manipulations potentially have certain risks in the treatment of DVT in rats.

Whole blood viscosity in the evaluation of thrombogenic milieu in mitral stenosis

2021 ◽  
Vol 15 (3) ◽  
pp. 181-190
Author(s):  
Elif H Ozcan Cetin ◽  
Mehmet S Cetin ◽  
Mustafa B Ozbay ◽  
Hasan C Könte ◽  
Nezaket M Yaman ◽  
...  
Keyword(s):  
Shear Rate ◽  
Blood Viscosity ◽  
Whole Blood ◽  
Mitral Stenosis ◽  
High Shear Rate ◽  
High Shear ◽  
Whole Blood Viscosity ◽  
Spontaneous Echo Contrast ◽  
Shear Rates ◽  
Low Shear

Aim: We aimed to assess the association of whole blood with thromboembolic milieu in significant mitral stenosis patients. Methodology & results: We included 122 patients and classified patients into two groups as having thrombogenic milieu, thrombogenic milieu (+), otherwise patients without thrombogenic milieu, thrombogenic milieu (-). Whole blood viscosity (WBV) in both shear rates were higher in thrombogenic milieu (+) group comparing with thrombogenic milieu (-). WBV at high shear rate and WBV at low shear rate parameters were moderately correlated with grade of spontaneous echo contrast. Adjusted with other parameters, WBV parameters at both shear rates were associated with presence of thrombogenic milieu. Discussion & conclusion: We found that extrapolated WBV at both shear rates was significantly associated with the thrombogenic milieu in mitral stenosis. This easily available parameter may provide additional perspective about thrombogenic diathesis.

Abnormal Blood Yield Stress as an Aetiological Factor in Postoperative Deep Venous Thrombosis

1975 ◽  
Author(s):  
W. V. Humphreys ◽  
A. Walker ◽  
D. Charlesworth
Keyword(s):  
Deep Vein Thrombosis ◽  
Yield Stress ◽  
Malignant Disease ◽  
Aetiological Factor ◽  
Venous Stasis ◽  
Vein Thrombosis ◽  
High Incidence ◽  
Deep Vein ◽  
Postoperative Deep Venous Thrombosis ◽  
Low Shear

An elevated blood viscosity could lead to increased venous stasis and a higher incidence of post-operative deep vein thrombosis. Immediately preoperatively we have measured, using a Contraves low shear 2 viscometer, blood yield stress and viscosity at high and low shear rate in 28 general surgical patients. These patients were then screened by the standard I125 fibrinogen technique to detect the development of deep vein thrombosis post-operatively.13 patients developed a deep vein thrombosis. These patients had a significantly higher blood yield stress, corrected to a standard haemoerit of 45%, than the others (P < 0.01 students t). All other viscosity parameters were normal in these patients. Patients with malignant disease had a very high incidence of thrombosis (90%: 30%) and significantly higher yield stress values (mean 0.26 dynes/cm2: mean 0.194 dynes/cm2, P < 0.0005 students t) compared to patients with benign disease.We conclude that a high blood yield stress could be an important aetiological factor in thrombosis and the high values obtained in patients with malignant disease could partly explain the high incidence in these patients.

Influence of lipids and obesity on haemorheological parameters in patients with deep vein thrombosis

2007 ◽  
Vol 98 (09) ◽  
pp. 621-626 ◽  
Author(s):  
Cristina Falcó ◽  
María Simó ◽  
Fernando Ferrando ◽  
Yolanda Mira ◽  
José Todolí ◽  
...  
Keyword(s):  
Deep Vein Thrombosis ◽  
Plasma Lipids ◽  
Hdl Cholesterol ◽  
Plasma Viscosity ◽  
The Body ◽  
Erythrocyte Aggregation ◽  
Control Group ◽  
Thrombotic Risk ◽  
Vein Thrombosis ◽  
Deep Vein

SummaryIt is not well established whether haemorheological alterations constitute independent risk factors for deep vein thrombosis (DVT).We have determined in 149 DVT patients and in 185 control subjects the body mass index (BMI), the haemorheological profile: blood viscosity (BV), plasma viscosity (PV), fibrinogen (Fg), erythrocyte aggregation (EA), erythrocyte deformability (ED) and plasma lipids. In the crude analysis BMI, Fg, PV, EA, triglycerides (TG) and ApoB were statistically higher and HDL cholesterol (HDL-Chol) statistically lower in DVT patients than in controls. No differences in BV and ED were observed. After BMI adjustment, Fg, PV and EA remained statistically higher in DVT cases than in controls (P=0.013; P=0.012; P=0.013; P=0.028, respectively). When the risk of DVT associated with these variables (using cut-offs that corresponded to the mean plus one SD of the control group) was estimated, EA>8.2 and PV>1.28 mPa·s were significantly associated with DVT even further adjustment for lipids and obesity (OR=2.78, P=0.004; OR=1.91, P=0.024, respectively). However, PV did not remain statistically significant after additional adjustment for Fg. When we consider together all the analyzed variables in order to control every variable for each other, TG>175 mg/dl (OR=3,2,P=0.004) and BMI>30 kg/m2 (OR=3.5, P=0.003), were also independently associated with a greater risk of DVT. Our results suggest that increased EA constitute an independent risk factor for DVT. However, when associated to hyperlipidaemia and obesity it further increases thrombotic risk.

scholarly journals A semi-infinite hydraulic fracture driven by a shear-thinning fluid

2018 ◽  
Vol 838 ◽  
pp. 573-605 ◽  
Author(s):  
Fatima-Ezzahra Moukhtari ◽  
Brice Lecampion
Keyword(s):  
Shear Rate ◽  
Power Law ◽  
Hydraulic Fracture ◽  
Complex Structure ◽  
Shear Thinning ◽  
High Shear Rate ◽  
Asymptotic Region ◽  
High Shear ◽  
Confining Stress ◽  
Low Shear

We use the Carreau rheological model which properly accounts for the shear-thinning behaviour between the low and high shear rate Newtonian limits to investigate the problem of a semi-infinite hydraulic fracture propagating at a constant velocity in an impermeable linearly elastic material. We show that the solution depends on four dimensionless parameters: a dimensionless toughness (function of the fracture velocity, confining stress, material and fluid parameters), a dimensionless transition shear stress (related to both fluid and material behaviour), the fluid shear-thinning index and the ratio between the high and low shear rate viscosities. We solve the complete problem numerically combining a Gauss–Chebyshev method for the discretization of the elasticity equation, the quasi-static fracture propagation condition and a finite difference scheme for the width-averaged lubrication flow. The solution exhibits a complex structure with up to four distinct asymptotic regions as one moves away from the fracture tip: a region governed by the classical linear elastic fracture mechanics behaviour near the tip, a high shear rate viscosity asymptotic and power-law asymptotic region in the intermediate field and a low shear rate viscosity asymptotic far away from the fracture tip. The occurrence and order of magnitude of the extent of these different viscous asymptotic regions are estimated analytically. Our results also quantify how shear thinning drastically reduces the size of the fluid lag compared to a Newtonian fluid. We also investigate simpler rheological models (power law, Ellis) and establish the small domain where they can properly reproduce the response obtained with the complete rheology.

RHEOLOGY AND VENOUS THROMBOEMBOLISM

1987 ◽  
Author(s):  
O DG Lowe
Keyword(s):  
Pulmonary Embolism ◽  
Deep Vein Thrombosis ◽  
Venous Thromboembolism ◽  
Blood Viscosity ◽  
Cell Aggregation ◽  
Red Cell ◽  
Vein Thrombosis ◽  
Deep Vein ◽  
Low Shear ◽  
Red Cell Aggregation

Changes in the composition of the blood, venous stasis, and interaction of the blood with the vessel wall (Virchow's triad) all have rheological aspects which may promote venous thrombogenesis.Blood composition and rheology. Increasing levels of venous haematocrit and fibrinogen increase bulk blood viscosity, especially at low shear rates such as are encountered in veins, when red cell aggregation occurs. Static blood requires a minimum shear stress for flow (yield stress), which is also strongly dependent on haematocrit and fibrinogen levels. Increases in haematocrit and fibrinogen also promote platelet adhesion and aggregation. Polycythaemia carries an increased risk of venous thromboembolism, which can be reduced by lowering the haematocrit; conversely, anaemic patients (renal failure, pernicious anaemia) have a subnormal prevalence of pulmonary embolism at autopsy. Increased preoperative levels of haematocrit, fibrinogen and blood viscosity predicted postoperative deep vein thrombosis in some studies, but not in others: they have complex relationships to other risk factors and illnesses. Postoperative changes in haematocrit, fibrinogen and blood viscosity may also be relevant to thrombogenesis, as may haemoconcentration in leg veins.Venous flow disturbance and rheology. The flow behaviour of particles and cells in venous valve pockets has been studied by Karino: particles and cells were observed to leave mainstream flow and circulate in paired vortices in low-shear areas within the valve pockets. A cell-poor hypoxic area at the apex of the valve pocket may favour thrombogenesis. Valve pockets might therefore act as in vivo aggregometers, with optimal conditions for activated cells or coagulation products to promote platelet and red cell aggregation, which might be facilitated by increases in haematocrit or fibrinogen. Sevitt has observed cellular aggregates in valve pockets at autopsy, which might act as a nidus for thrombus initiation. Successive layers of thrombus will disturb flow steamlines, as well as generating procoagulant activity: hence a series of "aggregometers" might result in successive bursts of thrombosis and the layered structure of venous thrombi observed by Sevitt. Variations in haematocrit, fibrinogen and red cell aggregation may influence stasis of blood following venous occlusion by thrombus, and hence affect thrombotic extension; they may also influence residual lung perfusion following pulmonary embolism.Therapeutic aspects of rheology. Leg stockings and other physical methods of preventing deep vein thrombosis may improve flow disturbance in valve pockets, as well as in axial veins. The efficacy of perioperative dextran in prevention of venous thromboembolism may partly reflect haemodilution and its rheological consequences. Likewise, postoperative defibrination with ancrod reduced the incidence and extent of deep vein thrombosis after hip surgery, which may partly reflect reductions in plasma viscosity and red cell aggregation. Defibrination with ancrod reduced the haemodynamic disturbance, and the mortality, of experimental pulmonary embolism in dogs, possibly by increasing residual perfusion.. Similarly, improved perfusion after thrombolytic therapy of pulmonary embolism in man may reflect the rheological consequences of fibrinogen depletion, as well as thrombolysis.

Characterizing the Rheology of Methane Hydrate Slurry in a Horizontal Water-Continuous System

SPE Journal ◽  
2019 ◽  
Vol 25 (03) ◽  
pp. 1026-1041 ◽  
Author(s):  
Baojiang Sun ◽  
Weiqi Fu ◽  
Zhiyuan Wang ◽  
Jianchun Xu ◽  
Litao Chen ◽  
...  
Keyword(s):  
Shear Rate ◽  
Natural Gas ◽  
Methane Hydrate ◽  
Shear Thickening ◽  
Continuous System ◽  
Shear Thinning ◽  
High Shear Rate ◽  
High Shear ◽  
Thickening Behavior ◽  
Low Shear

Summary Methane hydrate slurry in a water-continuous system is a significant production issue during pilot explorations for natural gas and natural gas hydrates in a deepwater environment. This work investigated the morphology and rheology of hydrate slurry with hydrate concentrations from 6 to 11% and shear rates from 20 to 700 s−1. Although hydrate slurry is widely considered a pseudoplastic fluid, in our experiment, hydrate slurry exhibited shear-thinning behavior in low-shear-rate conditions and shear-thickening behavior in high-shear-rate conditions. The breakup of agglomerates built up between hydrate particles by shear force induced shear-thinning behavior in low-shear-rate conditions. The collision between monodispersed hydrate particles resulted in shear-thickening behavior in high-shear-rate conditions. The critical shear rate was proposed to describe the transition between the shear-thinning and shear-thickening behaviors of the hydrate slurry, which was a function of the hydrate concentration. Empirical Herschel-Bulkley-type equations were developed to describe the rheology of the hydrate slurry for both conditions.

Whole blood viscosity predicts nondipping circadian pattern in essential hypertension

2020 ◽  
Vol 14 (14) ◽  
pp. 1307-1316
Author(s):  
Abdullah K Dolu ◽  
Ahmet Korkmaz ◽  
Harun Kundi ◽  
Umit Guray
Keyword(s):  
Essential Hypertension ◽  
Shear Rate ◽  
Blood Viscosity ◽  
Whole Blood ◽  
Blood Pressure Monitoring ◽  
High Shear Rate ◽  
High Shear ◽  
Whole Blood Viscosity ◽  
Protein Levels ◽  
Low Shear

Aim: We aimed to investigate the association between whole blood viscosity (WBV) and nondipping pattern in patients with essential hypertension. Materials & methods: A total of consecutive 530 patients who had been evaluated by ambulatory blood pressure monitoring were included. WBV was estimated by using hematocrit and plasma total protein levels for both WBV in low shear rate (0.5 s-1) and WBV in high shear rate (208 s-1) according to the de Simone’s formula. Results: In the multivariate analysis, low shear rate and high shear rate of WBV were associated independently with nondipping pattern in patients with essential hypertension. Conclusion: As a simple, inexpensive and noninvasive tool, WBV seems to be a significant predictor of nondipping hypertension.

Relationship of Particle Content and Size of Spherical Silica with the Flowability of Epoxy Molding Compounds for Large-Scale Integrated Circuits Packaging

2010 ◽  
Vol 92 ◽  
pp. 201-205 ◽  
Author(s):  
Ming Shan Yang ◽  
Yang Liu ◽  
Jie He ◽  
Lin Kai Li ◽  
Ze Wang
Keyword(s):  
Particle Size ◽  
Shear Rate ◽  
Integrated Circuits ◽  
Epoxy Resin ◽  
Large Scale ◽  
Particle Diameter ◽  
High Shear Rate ◽  
High Shear ◽  
Molding Compound ◽  
Low Shear

The melting viscosities of different kinds of epoxy resins have been investigated in this paper. The results showed that tetramethyl biphenyl epoxy resin(TMBP) has very low melting viscosity(0.02Pa•s at 150°C) and can be blended with ortho-cresol novolac epoxy resin(ECN) in order to decrease the melting viscosity of epoxy molding compound(EMC). When the content of TMBP in the blend of ECN/TMBP was up to 40wt%, the viscosity of the blend decreased to 0.15 Pa•s from 0.8 Pa•s of ECN. In addition, the effects of the content, particle size of silica on the flowability of EMC have been researched systematically in the paper. The results showed that the melting viscosity of EMC increased greatly with the filling increasing of silica, and the particle size and the match of silica with different particle diameter had markedly influenced on the flowability of EMC. The melting viscosity of system with higher filling content of silica changed complicatedly with the increasing of shear rate, i.e., the viscosity of the system decreased with the increasing of shear rate in the range of low shear rate, then increased with the increasing of shear rate in the range of high shear rate, but decreased again with the increasing of shear rate in the range of higher shear rate. The system filled by silica with small particle diameter had low melting viscosity at low shear rate and high melting viscosity at high shear rate, but the melting viscosity of the system filled by silica with large particle diameter changed by contraries.

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