Biorheology - Volume 26, issue 6

Article Type: Editorial

DOI: 10.3233/BIR-1989-26612

Citation: Biorheology, vol. 26, no. 6, pp. I-III, 1989

Authors: Silberberg, Alex | Copley, Alfred L.

Article Type: Editorial

DOI: 10.3233/BIR-1989-26601

Citation: Biorheology, vol. 26, no. 6, pp. 975-975, 1989

Authors: Agarwal, M. | King, M. | Rubin, B.K. | Shukla, J.B.

Article Type: Research Article

Abstract: The transport of mucus gel simulant (MGS) in a constricted simulated cough machine, using blood plasma as a serous layer simulant (SLS), was investigated. MGS was prepared from locust bean gum solutions crosslinked with varying amounts of added borate to produce gels of varying spinnability (filance). The model trachea was a plexiglass channel of rectangular cross-section with the plane bottom surface. The upper surface included a sinusoidal protrusion which provided a flow convergence with minimum gaps of 6, 4 and 2 mm. Experiments for mucus transport were conducted for these minimum gaps, as well as for the non-convergent case (12 …mm gap). Miniaturization of sample quantity was achieved by keeping the MGS layer depth constant (0.5 or 1 mm) but reducing the zone of loading from 13.4 cm to 1 cm, thus reducing the sample requirement to as little as 0.2 ml. MGS transport was determined as the minimum displacement of a line of marker dye placed in the MGS layer at the point of minimum constriction gap. It was shown that in all cases (dry as well as with SLS), MGS transport increased as the minimum constriction gap between the plane and the convergent top surface decreased. This increase was further enhanced if an SLS of lesser viscosity was used. It was also found that the transport of MGS increased as the depth of MGS layer increased or as the filance decreased in both non-constricted and constricted cases. The relationship between MGS transport and filance was maintained even in the presence of an SLS layer. Show more

Keywords: mucus, serous fluid simulant, model airway, cough, mucus transport

DOI: 10.3233/BIR-1989-26602

Citation: Biorheology, vol. 26, no. 6, pp. 977-988, 1989

Authors: Yamaguchi, Saburo | Niimi, Hideyuki

Article Type: Research Article

Abstract: Filtrability of a suspension of polymorphonuclear leukocytes (PMNs) was examined in a Nuclepore membrane filtration system utilizing a gradually reduced pressure difference with or without an additional negative pressure. The filtration process was continuously recorded using a TV-video system for data analysis. The PMN content in the filtrate was directly measured. The pressure-flow relation was analyzed in terms of the relative resistance of the PMN suspension to that of the suspending medium. The relative resistance of the PMN suspension increased with an increase in the filtered volume until it approached infinity at the level of low pressure difference (2.8 - …0 cmH2 O). The remarkable increase in flow resistance was closely associated with the plugging of PMNs in the membrane pores. At high pressure differences (12.8 - 10 cmH2 O, 7.8 - 5 cmH2 O), the relative resistance increased up to finite values, as the filtered volume increased. The variation in the relative resistance was greatly dependent upon the pressure difference or the flow condition. The amount of filtered cell fraction increased with an increase of additional pressure, indicating that the relative resistance was changed according to the rate of PMN plugging and dislodging in the pores of the membrane. Show more

Keywords: Filtration, Leukocyte plugging, Nuclepore membrane, Polymorphonuclear leukocyte, Relative resistance

DOI: 10.3233/BIR-1989-26603

Citation: Biorheology, vol. 26, no. 6, pp. 989-1002, 1989

Authors: Kuo, Cheng-Deng | Bai, Jing-Jang | Chien, Shu

Article Type: Research Article

Abstract: A phenomenological theory is formulated in analogy to the theory of population dynamics to account for the observed erythrocyte sedimentation–time and velocity–time curves. The least square fitting of experimental data to the derived equations is quite satisfactory. Several parameters in the proposed equations can be used to characterize these two curves of erythrocyte sedimentation: the biotic potential or intrinsic rate of decrease of the lacuna population, r; the total distance settled by the interface between plasma and red cell column, K·Δh; the maximal settling velocity of the interface, V max ; the time when V max occurs, tmv ; …and the final position of the interface, Hf . Show more

Keywords: Biotic potential, Blood sedimentation, ESR, Lacuna, Population dynamics

DOI: 10.3233/BIR-1989-26604

Citation: Biorheology, vol. 26, no. 6, pp. 1003-1010, 1989

Authors: Perktold, K. | Peter, R. | Resch, M.

Article Type: Research Article

Abstract: Blood flow is analysed by means of computer simulation in an idealized arterial bifurcation model which is pathologically altered by a saccular aneurysm. The theoretical study of the flow pattern and the paths of fluid particles is carried out under pulsatile Newtonian and non-Newtonian flow conditions. The governing equations are solved numerically with the use of the finite element method. The results show the disturbed blood flow in the bifurcation and the relatively low intra-aneurysmal flow circulation. In addition to the study of basic flow patterns in the segment, a comparison of non-Newtonian and Newtonian results is carried out. This …comparison proves that for the considered large artery model under physiological flow conditions where the yield number is relatively low there is no essential difference in the results. Show more

Keywords: hemodynamics, saccular aneurysm, numerical blood flow analysis, velocity pattern

DOI: 10.3233/BIR-1989-26605

Citation: Biorheology, vol. 26, no. 6, pp. 1011-1030, 1989

Authors: Bilsker, David L. | Waters, Christopher M. | Kippenhan, J. Shane | Eckstein, Eugene C.

Article Type: Research Article

Abstract: A rapid freezing method was developed to study the distributions of fluorescent platelet-sized particles in flows of blood suspensions through thin-walled capillary tubes. Segments of frozen tubes were mounted in a refrigerated microtome on the stage of an epifluorescence microscope. Sections of tube were cut away, images of newly exposed cross-sections were recorded on video tape, and distances of the particles from the wall were measured from recorded images. The distance data were used to construct histograms that were proportional to the local concentration. Results indicated that this method is suitable for the study of the distribution of platelet-sized particles …over a wide range of hematocrit, that the basic profile is reproducible to within 15%, and that the non-uniform profile is not a result of events at the tube entrance. Show more

Keywords: Erythrocytes, Platelets, Rheology, Biological Transport

DOI: 10.3233/BIR-1989-26606

Citation: Biorheology, vol. 26, no. 6, pp. 1031-1040, 1989

Authors: Kerber, C.W. | Heilman, C.B. | Zanetti, P.H.

Article Type: Short Communication

Keywords: Elastic model, flow visualization, carotid artery, silicone model, interventional

DOI: 10.3233/BIR-1989-26607

Citation: Biorheology, vol. 26, no. 6, pp. 1041-1049, 1989

Article Type: Abstract

DOI: 10.3233/BIR-1989-26608

Citation: Biorheology, vol. 26, no. 6, pp. 1051-1081, 1989

Article Type: Announcement

DOI: 10.3233/BIR-1989-26609

Citation: Biorheology, vol. 26, no. 6, pp. 1083-1083, 1989

Article Type: Correction

DOI: 10.3233/BIR-1989-26610

Citation: Biorheology, vol. 26, no. 6, pp. 1085-1085, 1989

Article Type: Other

DOI: 10.3233/BIR-1989-26611

Citation: Biorheology, vol. 26, no. 6, pp. 1087-1087, 1989