Biorheology - Volume 6, issue 2

Authors: Nuriel, E.H. | Bicher, H.I. | Van-Der-Lijn, E.

Article Type: Research Article

Abstract: The effect in vivo of high and low molecular weight colloids on red cell and platelet aggregation, has been investigated using the SFP method. High molecular weight colloids produce blood cell aggregation and an increase in ADP induced platelet aggregation. Low molecular weight colloids are devoid of such effects. The direct action of high molecular weight colloids, appears to be due to sensitization of the platelets, the effect being made evident by increased red cell or platelet aggregation.

DOI: 10.3233/BIR-1969-6201

Citation: Biorheology, vol. 6, no. 2, pp. 65-71, 1969

Authors: Kaibara, Makoto | Fukada, Eiichi

Article Type: Research Article

Abstract: The steady flow viscosity of blood and plasma during clotting was measured by a coaxial cylinder viscometer. The relation between the stress and the shear rate during clotting were well represented by Casson’s equation. The dynamic modulus and loss modulus during clotting were also measured by a newly developed dynamic viscoelastic apparatus. Two kinds of equation were proposed to describe the relation between the viscoelastic modulus E ′ or E ″ and the clotting time.

DOI: 10.3233/BIR-1969-6202

Citation: Biorheology, vol. 6, no. 2, pp. 73-84, 1969

Authors: Valanis, K.C. | Sun, C.T.

Article Type: Research Article

Abstract: In this paper, the Poiseuille flow of blood is studied. Blood is assumed to be a fluid with couple stress. In order to verify that the rheological properties of blood can be explained in terms of the linear couple stress theory, we compare the velocity profiles of theoretical solutions with the ones obtained experimentally. Very good agreement is observed by choosing the appropriate values for the couple stress parameters α ¯ and η ¯ for different concentration factors of erythrocytes. The effects of the concentration factor on the velocity profile …as well as on the values of the velocity are also discussed. We conclude that as far as Poiseuille flow is concerned blood flow characteristics can be explained in terms of the linear couple stress theory. Show more

DOI: 10.3233/BIR-1969-6203

Citation: Biorheology, vol. 6, no. 2, pp. 85-97, 1969

Authors: Kline, Kenneth A. | Allen, Stuart J.

Article Type: Research Article

Abstract: A continuum model of fluid suspensions is applied to the problem of unsteady tube flow of a fluid in which deformations of suspended particles are negligible. An expression is obtained for the volumetric flow rate as a function of suspension concentration. The solution is shown to reduce, as the suspension concentration goes to zero, to the classical solution of Womersley [J. Physiol. 127 , 553, 1955]. Tables are given to allow easy calculation of flow terms for various concentrations.

DOI: 10.3233/BIR-1969-6204

Citation: Biorheology, vol. 6, no. 2, pp. 99-108, 1969

Authors: Lew, H.S. | Fung, Y.C.

Article Type: Research Article

Abstract: The motion of the plasma trapped between two adjacent red blood cells moving with a constant speed in a capillary blood vessel is studied. In this study, the convective inertia force of the plasma is neglected in comparison with the viscous stresses on the basis of the smallness of the Reynolds number of the flow in the capillary. The red cells are approximated by cylindrical pill boxes whose radii are the same as that of the blood vessel. The capillary blood vessel is approximated by a circular cylindrical tube with impermeable wall. With such an ideal model the velocity and …pressure fields are determined. Show more

DOI: 10.3233/BIR-1969-6205

Citation: Biorheology, vol. 6, no. 2, pp. 109-119, 1969

Authors: Jacobs, H.R.

Article Type: Research Article

Abstract: A capillary tube viscometer is described that is capable of operating at very low shear rates. It virtually eliminates error from meniscal effects.

DOI: 10.3233/BIR-1969-6206

Citation: Biorheology, vol. 6, no. 2, pp. 121-126, 1969

Authors: Miller, C. Eugene

Article Type: Research Article

Abstract: Particle flow in a mechanical model of the mammalian mucociliary system is accounted for by analysis of streamlines, streak lines, and particle path lines. Streamlines were drawn from data obtained by techniques of hot-wire anemometry; multiple streak lines were represented by patterns formed in injected dye; particle path lines were drawn from analysis of films showing the movement of a single dye particle in the flow field. The relationship between the three flow lines is evidenced by the fact that both particle path lines and multiple streak lines could be generated from the streamlines. The relevance of this flow analysis …to the mammalian mucociliary system is indicated by the similarity of the Reynolds numbers for the mechanical and biological systems. Show more

DOI: 10.3233/BIR-1969-6207

Citation: Biorheology, vol. 6, no. 2, pp. 127-135, 1969

Authors: Halikas, G. | Sheppard, C.W.

Article Type: Research Article

Abstract: The absolute viscosity of water and relative viscosity of blood were measured by the transpiration method using 15 viscometers of different radii and lengths. Contrary to a recent investigation, there was no evidence that the viscosity of water is anomalous. The absolute, viscosity of water obtained was within 0.4 per cent of the published value at 38°C. Canine blood, on the other hand displayed a decrease in relative viscosity with decreasing capillary diameter, confirming the Fahraeus-Lindqvist effect.

DOI: 10.3233/BIR-1969-6208

Citation: Biorheology, vol. 6, no. 2, pp. 137-142, 1969

Authors: Scott Blair, G.W.

Article Type: Research Article

Abstract: The concept of “basic equations” is discussed. Maxwell proposed a basic equation for the relaxation of stress in a material depicted as an elastic and a viscous element in series; and Lord Kelvin proposed a similar equation for these elements in parallel. Although some materials obey these equations, their proposers were quite clear that further modifications would be needed for many real systems. The Maxwell equation for relaxation at constant strain and the Kelvin equation for the build-up of strain at constant stress give simple logarithmic relations between two dimensionless ratios, one rheological and the other temporal. Some …years ago, an empirical equation was found to relate the complex modulus of coagulating milk and also blood, to the time following the first signs of coagulation. In the present paper, it is shown that, making the three most probable assumptions about the limits and form of the coagulation curve, this hitherto empirical equation is immediately derived. It shows a striking parallelism with the Maxwell and Kelvin equations. In the latest stages of normal blood coagulation, however, the equation does not hold. This “ceiling effect” is doubtless due to the rapidly increasing shortage of unattached possible junction-points on the long-chain molecules but its quantitative nature is still obscure. Show more

DOI: 10.3233/BIR-1969-6209

Citation: Biorheology, vol. 6, no. 2, pp. 143-150, 1969

Authors: Stoltz, J.F. | Larcan, A.

Article Type: Letter

DOI: 10.3233/BIR-1969-6210

Citation: Biorheology, vol. 6, no. 2, pp. 151-152, 1969