Biorheology - Volume 11, issue 4

Authors: Singh, Megha | Coulter Jr., N.A.

Article Type: Research Article

Abstract: The effect of dilution on the apparent viscosity of high hematocrit blood, with flow improver and plasma expander type of dextrans, was studied in a capillary viscometer. All experiments were performed on fresh heparinized dog blood. It was observed that blood dextran mixtures at normal hematocrit (41 per cent) have higher apparent viscosity than that of whole blood, at the same hematocrit, at all flow rates, and that under certain conditions even low hematocrit (23 per cent) mixtures have a higher apparent viscosity than whole blood of normal hematocrit. Analysis of the data indicates that the viscosity of the suspending …medium is a major determinant of the apparent viscosity of whole blood. Show more

DOI: 10.3233/BIR-1974-11401

Citation: Biorheology, vol. 11, no. 4, pp. 217-225, 1974

Authors: Cerny, L.C. | Cook, F.B. | Stasiw, D.M.

Article Type: Research Article

Abstract: The Payne and Pell solution to the Stokes flow problem for axially symmetric bodies is reexamined and several corrections to the theory are presented. The corrected equations are then used to calculate the drag expected for spherical, lens and sickle shaped bodies and a correlation between the drag and the sphericity index is made. The geometric similarities between the shapes treated here and the shapes assumed by red cells during normal flow and that produced by chemical action is noted and the possibility of utilizing the Payne-Pell theory as a basis for a mathematical treatment of these shape changes is …explored. Show more

DOI: 10.3233/BIR-1974-11402

Citation: Biorheology, vol. 11, no. 4, pp. 227-233, 1974

Authors: Cerny, L.C. | Cook, F.B. | Stasiw, D.M.

Article Type: Research Article

Abstract: The viscosity of whole blood was determined on subjects with sickle cell trait. This study was performed on an aging population with a Wells Brookfield cone-plate viscometer. The investigation indicated an age-related pattern. The viscosity-shear rate curve of whole blood of the young SA age group is at least 23 per cent greater than the young AA age group. One old SA patient showed a hemorheological flow pattern similar to the data of oxygenated SS blood. Initial measurements employing a microcalorimcter indicate the usefulness of this technique. It appears possible to distinguish a difference in the heat of mixing …urea with HbAA and HbAS. These experiments also point to the use of microcalorimetry for objective evaluation of sickle cell therapy, and for prediction of therapeutic drug dosages. Show more

DOI: 10.3233/BIR-1974-11403

Citation: Biorheology, vol. 11, no. 4, pp. 235-239, 1974

Authors: Fung, J.S.K. | Canham, P.B.

Article Type: Research Article

Abstract: The mode of coming together in doublets of human red cells lying on a coverslip was observed. There were two mechanisms: firstly. two single cells contact and then one slides over the other, with a maximum velocity near half-overlap; secondly, two cells in contact “crest” upwards at the junction, the cells bending, to achieve apposition. The sliding mode occurs for cells from normal blood. The cresting mode occurs for cells from blood having a high erythrocyte sedimentation rate. and occurs for cells suspended in Ringer solution containing polyvinylpyrrolidone at greater than 4 g/l. The effect of the amount of a …rouleau-inducing substance was studied using 360,000 molecular weight PVP from 1 to 7 g/l. of Ringer solution. An increase in concentration of PVP results in an increase in rate of doublet formation, and a change of mode from sliding to cresting at a concentration of 4 g/l. Show more

DOI: 10.3233/BIR-1974-11404

Citation: Biorheology, vol. 11, no. 4, pp. 241-251, 1974

Authors: Sartory, W.K.

Article Type: Research Article

Abstract: The effect of diffusion on the sedimentation of erythrocytes is reexamined analytically. and it is concluded that the diffusivity of erythrocytes is too small by several orders of magnitude to account for the available experimental results. An alternative monodisperse hindered sedimentation model is found to give fairly good agreement with the available experiments, at least after 1 hr. A polydisperse hindered sedimentation model is considered briefly, but it is found to be unable to completely account for the limitations of the monodisperse model.

DOI: 10.3233/BIR-1974-11405

Citation: Biorheology, vol. 11, no. 4, pp. 253-264, 1974

Authors: McCutchen, C.W.

Article Type: Research Article

Abstract: Miniviscometer is a Couette instrument that can determine the viscosity vs shear-rate relation of a 0.2 cm3 sample of fluid. The inner member, the one that docs not rotate, is entirely surrounded by the outer member. It is kept from rotating by a magnetic field produced by an electromagnet. The electromagnet current just sufficient to prevent rotation is proportional to the viscous torque, and thus to the product of shear rate and viscosity. The inner member has a conical bottom end that mates with a slightly blunter conical cavity in the outer member. This maintains across the bottom …the same shear rate as that between the cylindrical surfaces of inner and outer, and serves as a bearing to keep the inner member centralized. Friction of this bearing is kept low by making the inner member as a Cartesian diver and adjusting its density so it just barely sinks in the liquid under investigation. Show more

DOI: 10.3233/BIR-1974-11406

Citation: Biorheology, vol. 11, no. 4, pp. 265-277, 1974

Authors: Sharma, M.G.

Article Type: Research Article

DOI: 10.3233/BIR-1974-11407

Citation: Biorheology, vol. 11, no. 4, pp. 279-291, 1974

Authors: Ossoff, Robert | Charm, Stanley E.

Article Type: Research Article

DOI: 10.3233/BIR-1974-11408

Citation: Biorheology, vol. 11, no. 4, pp. 293-299, 1974

Authors: Spinelli, F.R. | Meier, Ch.D.

Article Type: Research Article

DOI: 10.3233/BIR-1974-11409

Citation: Biorheology, vol. 11, no. 4, pp. 301-306, 1974

Authors: Ishizaka, Shozo

Article Type: Research Article

DOI: 10.3233/BIR-1974-11410

Citation: Biorheology, vol. 11, no. 4, pp. 307-311, 1974