Biorheology - Volume 10, issue 4

Authors: Munter, William A. | Stein, Paul D.

Article Type: Research Article

Abstract: Experimental investigations of the flow characteristics of blood have been reported only at shear rates analogous to conditions of flow that would be expected to occur in smaller arteries or the microcirculation. If one is to consider the rheological behavior of blood at peak levels of flow under conditions typically found in arteries of moderate size, higher rates of shear must be examined. In this study, it was found that at these higher rates of shear the blood behaves as a Newtonian fluid. This has broad implications in the study of hemorheological models of the cardiovascular system. It permits one …to analyze disturbed flow in regions of high shear by utilization of equations which describe the fluid dynamics of Newtonian fluids. Show more

DOI: 10.3233/BIR-1973-10401

Citation: Biorheology, vol. 10, no. 4, pp. 501-508, 1973

Authors: Zingg, W. | Sulev, J.C. | Morgan, C.D.

Article Type: Research Article

Abstract: Blood viscosity determinations using the Wells–Brookfield cone plate viscometer can be organized as a routine laboratory procedure. Standing, anticoagulant concentration, and centrifugation of the sample as well as the nutritional state of the subject, do not influence the blood viscosity values at the level of accuracy achieved by the instrument.

DOI: 10.3233/BIR-1973-10402

Citation: Biorheology, vol. 10, no. 4, pp. 509-515, 1973

Authors: Chu, Billie Mae | Oka, Syoten

Article Type: Research Article

Abstract: A finite deformation solution has been developed for the radial, circumferential and axial stress distributions in an axially stretched hollow cylindrical tube in equilibrium under constant internal and external pressure. These results for longitudinal tethering (i.e. axial stretch) of the tube have been compared with the case of plane strain finite deformation and it has been shown that the plane strain results reduce to the values given in the classical theory of elasticity when the deformations become infinitesimal. It has also been shown that the resultant hoop tension in the vessel wall may take either positive or negative values, depending …upon the pressure and the radius of the tube, and furthermore that the resultant hoop tension is less for the axially stretched tube than for the un stretched tube in the intermediate to large range of circumferential wall stretch. A salient feature of the finite deformation solution is its treatment of strain induced anisotropy of the cylindrical wall. An initially isotropic material exhibits elastic moduli that are equal in all directions but when the material of a cylindrical tube undergoes finite deformation the elastic moduli are no longer equal in all directions if calculated as incremental moduli. The distinction between such strain induced anisotropy of an initially isotropic material and true material anisotropy needs to be incorporated in future studies of vessel walls. Show more

DOI: 10.3233/BIR-1973-10403

Citation: Biorheology, vol. 10, no. 4, pp. 517-525, 1973

Authors: Newman, D.L. | Twinn, K.W.

Article Type: Research Article

Abstract: The plasma cholesterol concentration in a group of seven beagle dogs was increased to ∼1000 mg/100 ml with a high cholesterol diet. Measurements of the whole blood and plasma viscosity were made at various plasma cholesterol concentrations. The viscosity determinations were carried out using a cone and plate micro viscometer operated at 37°C and at shear rates of 11.5. 23, 46, 115 and 230 sec−1 . The whole blood samples were adjusted to a haematocrit of 40 per cent before the viscosity determination. It was found that viscosity of whole blood was dependent on the cholesterol concentration whilst plasma viscosity …was unaffected. The increase in whole blood viscosity as a result of an increase in cholesterol level was more marked at the lower shear rates. Show more

DOI: 10.3233/BIR-1973-10404

Citation: Biorheology, vol. 10, no. 4, pp. 527-531, 1973

Authors: Copley, A.L. | King, R.G.

Article Type: Research Article

DOI: 10.3233/BIR-1973-10405

Citation: Biorheology, vol. 10, no. 4, pp. 533-539, 1973

Authors: King, R.G. | Copley, A.L.

Article Type: Research Article

DOI: 10.3233/BIR-1973-10406

Citation: Biorheology, vol. 10, no. 4, pp. 541-543, 1973

Authors: Schmid-Schönbein, H. | Gosen, J.V. | Klose, H.J.

Article Type: Research Article

DOI: 10.3233/BIR-1973-10407

Citation: Biorheology, vol. 10, no. 4, pp. 545-551, 1973

Authors: Prost-Dvojakovic, R.J. | Samama, M. | Stoltz, J.F. | Larcan, A. | Streiff, F. | Bezard, J.

Article Type: Research Article

Abstract: L’influence des sels d’acides gras saturés et insaturés de C8 à C22 sur l’agrégation des plaquettes humaines est comparée dans le cadre de deux techniques différentes d’investigation: le test classique photométrique et la pression de filtration. Dans le test classique photométrique, les acides gras induisent une courbe de déviation progressive et irréversible, témoin à la fois de l’agrégation des plaquettes et de la conjugaison vraisemblable de l’acide gras avec les protéines plasmatiques. L’existence et l’intensité de l’agrégation plaquettaire sont liées au poids moléculaire de la chaîne d’acides gras considérée et inhibées par la présence de doubles liaisons. …Avec la technique de la pression de filtration de PRP, on trouve une augmentation de celle-ci en fonction du nombre de molécules de carbone de la chaîne utilisée en bonne corrélation pour les acides gras saturés avec le test précédent. La diminution de la pression de filtration provoquée par la présence d’une double liaison, en particulier pour l’érucate, est d’un degré supérieur à l’inhibition du test photométrique. La taille, la cohésion des agrégats pourraient être la cause de cette discordance et le rôle de l’activation ou non activation du facteur XII est suggéré comme un mécanisme possible d’intcrprétation. Show more

DOI: 10.3233/BIR-1973-10408

Citation: Biorheology, vol. 10, no. 4, pp. 553-559, 1973

Authors: Connell, R.S. | Swank, R.L. | Webb, M.C.

Article Type: Research Article

DOI: 10.3233/BIR-1973-10409

Citation: Biorheology, vol. 10, no. 4, pp. 561-564, 1973

Authors: Cerny, L.C. | Stasiw, D.M. | Tinelli, W.C.

Article Type: Research Article

DOI: 10.3233/BIR-1973-10410

Citation: Biorheology, vol. 10, no. 4, pp. 565-575, 1973