Biorheology - Volume 19, issue 6

Authors: Bitbol, M. | Leterrier, F.

Article Type: Research Article

Abstract: When a suspension of erythrocytes labeled in their membrane with a fatty acid paramagnetic molecule is allowed to flow in a flat quartz sample cell, the recorded electron paramagnetic spectra change as a function of the orientation of the cell in the magnetic field. This indicates that the red cells are themselves oriented in the flow. Such spectral variations have been reproduced by a numerical simulation procedure, which allowed us to quantify the proportion of oriented red blood cells by measuring the amplitude of sone characteristic lines on the experimental spectra. Orientation rates were then measured as a function of …various rheological parameters, such as shear rate, hematocrit and viscosity of the suspending medium. The kinetics of the disorientation process was determined by stopping the flow. Show more

Keywords: Spin label, Erythrocyte orientation

DOI: 10.3233/BIR-1982-19601

Citation: Biorheology, vol. 19, no. 6, pp. 669-680, 1982

Authors: Bloor, M.I.G.

Article Type: Research Article

Abstract: The flow within a concentric cylinder viscometer is analysed theoretically. A model for the whole blood is developed which takes account of the plastic properties of blood together with the effect of red cell migration. The results of the analysis indicate the possibility of a solid and liquid phase co-existing in the viscometer at sufficiently low shear rates. The effect of the migration of deformable aggregates within the blood away from solid boundaries is also considered and a correction technique for experiments is suggested.

DOI: 10.3233/BIR-1982-19602

Citation: Biorheology, vol. 19, no. 6, pp. 681-694, 1982

Authors: Tokita, Masayuki | Hikichi, Kunio | Niki, Ryoya | Arima, Shunrokuro

Article Type: Research Article

Abstract: Dynamic mechanical measurements were carried out to clarify the mechanism of the clotting process of casein micelle solution. It was found that the clotting process of casein micelle solution was formally expressed by a first order reaction. The enzyme concentration dependence of the latent time tL and the rate constant of gelation Kg were found to be tL ∞ [E]−1.1 and Kg ∞ [E]1.0 , respectively. These results were interpreted on the basis of the theory of gelation. The results obtained here were found to agree with the theoretical conjectures. The casein micelle concentration dependence of …the complex rigidity was also studied. Show more

Keywords: Casein Micelle, Chymosin, Rennet, Complex Rigidity, Ultrafiltrated Serum, Clotting Curve

DOI: 10.3233/BIR-1982-19603

Citation: Biorheology, vol. 19, no. 6, pp. 695-705, 1982

Authors: Tandon, P.N. | Misra, J.K. | Srivastava, K.K.

Article Type: Research Article

Abstract: Most of the physiological fluids are transported through peristalsis of the walls which is the inherent neuromuscular property of tube smooth muscle structure. The present paper deals with the transport of seminal fluid introducing the microstructural effects and peripheral-layer viscosity effects on the flow rate and the drag for the system. It has been Observed that the flow rate increases tremendously with the decrease of the peripheral layer viscosity whereas a reverse trend has been noted for the frictional drag. Further other sub-structural effects i.e. the effects of relative rotational viscosity and Viscosity gradients have also been broughtout and discussed.

Keywords: Seminal Fluid, Micro-structural effects

DOI: 10.3233/BIR-1982-19604

Citation: Biorheology, vol. 19, no. 6, pp. 707-715, 1982

Authors: Eckstein, E.C.

Article Type: Research Article

Abstract: Interactions among red cells and platelets in flowing blood result in significant dispersive motions of the platelets, which are commonly modelled by an effective diffusion coefficient. This paper examines an additional platelet flux, termed rheophoresis, to model platelet motions due to the gradient of hematocrit. Rheophoretic effects occur near walls because geometric exclusion and fluid mechanical repulsion of red cells create a hematocrit gradient there. Models using rheophoretic flux show that platelet concentration near walls is elevated; such models provide a consistent interpretation of available experimental data. Estimates show the coefficients for traditional effective diffusivity and the rheophoretic diffusivity have …similar magnitudes. The effects of rheophoresis on axial development of platelet concentration profiles and on surface deposition are discussed. Show more

Keywords: Platelets, Blood Flow, Suspensions, Diffusion, Thermophoresis

DOI: 10.3233/BIR-1982-19605

Citation: Biorheology, vol. 19, no. 6, pp. 717-724, 1982

Authors: van Oss, Carel J.

Article Type: Letter

DOI: 10.3233/BIR-1982-19606

Citation: Biorheology, vol. 19, no. 6, pp. 725-725, 1982

Authors: Nash, G.B. | Wyard, S.J.

Article Type: Letter

DOI: 10.3233/BIR-1982-19607

Citation: Biorheology, vol. 19, no. 6, pp. 727-727, 1982

Article Type: Announcement

DOI: 10.3233/BIR-1982-19608

Citation: Biorheology, vol. 19, no. 6, pp. 729-731, 1982

Article Type: Announcement

DOI: 10.3233/BIR-1982-19609

Citation: Biorheology, vol. 19, no. 6, pp. 733-735, 1982

Authors: Kiesewetter, H. | Dauer, U. | Teitel, P. | Schmid-Schönbein, H. | Trapp, R.

Article Type: Research Article

Abstract: The SER allows the “deformability” of individual red blood cells to be quantitated by determining their passage time through a pore (d=5.8 μ m, 1 =50 μ m) under the shear stresses of 1.5 Pa-4 Pa. Using this system, we examined the influence of: 1. cytoplasmic viscosity, 2. membrane viscoelastic properties, 3. area to volume relationship. To change these determinants of RBC-deformability, the cells have been altered with 1. Acetylphenylhydrazine (0.016 mol/l), 2.diamide (0.5 mmol/l), 3. osmotic swelling (200 mosm/l) and osmotic shrinking (480 mosm/l) by suspending the cells in hypo- and hypertonic saline. The passage time has been found …to be primarily influenced by changes in cytoplasmic viscosity. The same cells when tested in 4 other systems considered to measure RBC-deformability (filtrometer, packed cell viscometry, rheoscope and ektacytometry) behaved differently. Show more

Keywords: RBC-Deformability, Single-Erythrocyte-Rigidometer, Constant Shear Stress Viscometer, Constant Shear Stress Viscometer, Polymicroviscometer, Rheoscope-Ektacytometer

DOI: 10.3233/BIR-1982-19610

Citation: Biorheology, vol. 19, no. 6, pp. 737-753, 1982