Biorheology - Volume 23, issue 5

Article Type: Editorial

DOI: 10.3233/BIR-1986-23510

Citation: Biorheology, vol. 23, no. 5, pp. I-III, 1986

Authors: Copley, Alfred L.

Article Type: Editorial

DOI: 10.3233/BIR-1986-23501

Citation: Biorheology, vol. 23, no. 5, pp. 435-441, 1986

Authors: Crewe, K.H. | Feuerstein, I.A.

Article Type: Research Article

Abstract: The adhesion and detachment of human washed platelets was studied on the surface of the larger tube of a tubular expansion. Measurements were made within the vortex, at the reattachment point and downstream of the vortex. Fluorescent video-microscopy of mepacrine labelled platelets was used to record data continuously. Flow was from the smaller to the larger tube at Reynolds numbers (based on upstream conditions) of 75.4 and 212.2. Measurements of the adhesion efficiency for initially contacting cells and an overall adhesion efficiency were made. These efficiencies decreased with increasing Reynolds number. There was a pattern of variability for both efficiencies …with respect to position and Reynolds number which is consistent with the generation of the unstable flow at the reattachment point. Show more

Keywords: fibrinogen, platelet adhesion, video-microscopy, vortex flow

DOI: 10.3233/BIR-1986-23502

Citation: Biorheology, vol. 23, no. 5, pp. 443-452, 1986

Authors: Gates, R.S. | Pitt, R.E. | Ruina, A. | Cooke, J.R.

Article Type: Research Article

Abstract: The appropriateness of several elastic constitutive laws for apple and potato cell walls is tested using uniform cell inflation data. Whole-tissue stress-strain behavior under uniaxial loading is predicted from an analysis of the compression of a conglomerate of cells in a simple arrangement.

Keywords: vegetative tissue, elastic constitutive laws

DOI: 10.3233/BIR-1986-23503

Citation: Biorheology, vol. 23, no. 5, pp. 453-466, 1986

Authors: Araiso, T. | Shindo, Y. | Arai, T. | Nitta, J. | Kikuchi, Y. | Kakiuchi, Y. | Koyama, T.

Article Type: Research Article

Abstract: The viscosity and the order in the interior of human erythrocyte membranes were investigated by the fluorescence depolarization technique in the nanosecond region with 1,6-diphenyl-1,3,5-hexatriene (DPH). After pulsed excitation with a polarized light, the fluorescence anisotropy ratio of DPH in membranes rapidly decreased and gave a final value (r∞ ). The rate of initial decrease and the value of r∞ related to the viscosity in the interior of the membranes and a wobbling angle of DPH which reflects a size of range for the phospholipid motion relating to the order of membrane structure. For normal human erythrocyte …membranes the viscosity and the wobbling angle were obtained to be 0.82 poise and 42°, at 37°C. Similar values were obtained for spectrin-free membranes. Hardened membranes by the cross-linking of the cytoskeletal proteins with glutaraldehyde showed a small wobbling angle of 37°, but the viscosity of them was unchanged. Show more

Keywords: membrane viscosity, erythrocyte, lipid bilayer, fluorescence depolarization, wobbling-in-cone model, DPH

DOI: 10.3233/BIR-1986-23504

Citation: Biorheology, vol. 23, no. 5, pp. 467-483, 1986

Authors: Black, R.A. | How, T.V. | Whittington, R.B.

Article Type: Research Article

Abstract: The Authors have looked at six proprietary rotational viscometers. It was not practicable to examine them all in the same detail, but the information suffices to show how results of reasonable accuracy may be obtained from any of them. Tests on Newtonian liquids show that these instruments have calibration-factors which are essentially functions of the shear-rate to which the calibrant is subjected. In some cases, the calibration factor is also strongly dependent upon the viscosity of the calibrant itself. However, it is shown that all of these instruments can yield results on Newtonian liquids with an accuracy of about ± …3%, but only at rates of shear involving sufficiently high torques. Having looked at the different responses of these individual instruments, the Authors recommend that users should calibrate their own instruments against a range of Newtonian liquids. The accuracies mentioned above are, of course, for Newtonian liquids; and when the viscometer is used in blood-studies, adoption of a wider error-band may be necessary. Show more

Keywords: Blood viscosity, Hematocrit

DOI: 10.3233/BIR-1986-23505

Citation: Biorheology, vol. 23, no. 5, pp. 485-498, 1986

Authors: Chaturani, P. | Samy, R. Ponnalagar

Article Type: Research Article

Abstract: The effects of non-Newtonian nature of blood and pulsatility on flow through a stenosed tube have been investigated. A perturbation method is used to analyse the flow. It is of interest to note that the thickness of the viscous flow region is non-uniform (changing with axial distance). An analytic relation between viscous flow region thickness and red cell concentration has been obtained. It is important to mention that some researchers have obtained an approximate solution for the flow rate-pressure gradient equation (assuming the ratio between the yield stress and the wall shear to be very small in comparison to unity); …in the present analysis, we have obtained an exact solution for this non-linear equation without making that assumption. The approximate and exact solutions compare well with one of the exact solutions. Another important result is that the mean and steady flow rates decrease as the yield stress θ increases. For the low values of the yield stress, the mean flow rate is higher than the steady flow rate, but for high values of the yield stress, the mean flow rate behaviour is of opposite nature. The critical value of the yield stress at which the flow rate behaviour changes from one type to another has been determined. Further, it seems that there exists a value of the yield stress at which flow stops for both the flows (steady and pulsatile). It is observed that the flow stop yield value for pulsatile flow is lower than the steady flow. The most notable result of pulsatility is the phase lag between the pressure gradient and flow rate, which is further influenced by the yield stress and stenosis. Another important result of pulsatility is the mean resistance to flow is greater than its steady flow value, whereas the mean value of the wall shear for pulsatile flow is equal to steady wall shear. Many standard results regarding Casson and Newtonian fluids flow, uniform tube flow and steady flow can be obtained as the special cases of the present analysis. Finally, some applications of this theoretical analysis have been cited. Show more

Keywords: Stenosed arteries, Non-Newtonian fluids, Blood rheology

DOI: 10.3233/BIR-1986-23506

Citation: Biorheology, vol. 23, no. 5, pp. 499-511, 1986

Article Type: Abstract

DOI: 10.3233/BIR-1986-23507

Citation: Biorheology, vol. 23, no. 5, pp. 513-547, 1986

Authors: Popel, Aleksander S.

Article Type: Book Review

DOI: 10.3233/BIR-1986-23508

Citation: Biorheology, vol. 23, no. 5, pp. 549-550, 1986

Article Type: Correction

DOI: 10.3233/BIR-1986-23509

Citation: Biorheology, vol. 23, no. 5, pp. 551-551, 1986