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Biorheology is an international interdisciplinary journal that publishes research on the deformation and flow properties of biological systems or materials. It is the aim of the editors and publishers of
Biorheology to bring together contributions from those working in various fields of biorheological research from all over the world. A diverse editorial board with broad international representation provides guidance and expertise in wide-ranging applications of rheological methods to biological systems and materials.
The aim of biorheological research is to determine and characterize the dynamics of physiological processes at all levels of organization. Manuscripts should report original theoretical and/or experimental research promoting the scientific and technological advances in a broad field that ranges from the rheology of macromolecules and macromolecular arrays to cell, tissue and organ rheology. In all these areas, the interrelationships of rheological properties of the systems or materials investigated and their structural and functional aspects are stressed.
The scope of papers solicited by
Biorheology extends to systems at different levels of organization that have never been studied before, or, if studied previously, have either never been analyzed in terms of their rheological properties or have not been studied from the point of view of the rheological matching between their structural and functional properties. This biorheological approach applies in particular to molecular studies where changes of physical properties and conformation are investigated without reference to how the process actually takes place, how the forces generated are matched to the properties of the structures and environment concerned, proper time scales, or what structures or strength of structures are required.
Biorheology invites papers in which such 'molecular biorheological' aspects, whether in animal or plant systems, are examined and discussed. While we emphasize the biorheology of physiological function in organs and systems, the biorheology of disease is of equal interest. Biorheological analyses of pathological processes and their clinical implications are encouraged, including basic clinical research on hemodynamics and hemorheology.
In keeping with the rapidly developing fields of mechanobiology and regenerative medicine,
Biorheology aims to include studies of the rheological aspects of these fields by focusing on the dynamics of mechanical stress formation and the response of biological materials at the molecular and cellular level resulting from fluid-solid interactions. With increasing focus on new applications of nanotechnology to biological systems, rheological studies of the behavior of biological materials in therapeutic or diagnostic medical devices operating at the micro and nano scales are most welcome.
Abstract: For the purpose to observe the possible vessel wall damage by deionization of the related anionic groups the perfusion test of rat kidney and aorta with cationic iron colloid particles and the injection experiments with albumin-poly-L-lysine complex were carried out. By staining the fixed tissue sections with the cationic iron colloid at pH 7.3 the ionized anionic sites on vessel walls have been demonstrated histochemically. The perfusion test of living tissue with the cationic iron colloid induced the desquamation of the endothelial cells. The perfused colloid particles were adsorbed to the whole endothelial cell surfaces facing to luminal and subliminal…sides. Albumin-poly-L-lysine complex injected into vein deposited in the subendothelial spaces of glomerular capillaries through the endothelial cell layer having the well-kept anionic barriers. Discussion was made on possible damage of vessels due to the deionization of anionic groups of endothelial cells and serum proteins by general cationic molecules.
Abstract: The method of the tangent simple systems is applied to the study of the viscoelastic behaviour of human blood in unstationary flow for rectangular steps and triangular ramps of shear rate. The tangent systems we utilize, Maxwell liquids, enable us to determine, at every point of the rheograms, apparent instantaneous values of retardation or relaxation time, viscosity coefficient and elasticity modulus of the studied blood samples, and to plot the curves of variation of these parameters as a function of flow duration. A qualitative interpretation of the results is proposed from data on the aggregation-disaggregation kinetics of red blood cells.…Examples are given for samples of normal and pathological bloods.
Abstract: We studied the effects of expectorants (mucolytic agents) in vivo on the relaxation behavior of sputum viscoelasticity. Seven female and thirty-three male patients (56.8 ± 19.3 yrs, range: 21 to 82 years old) with a chronic pulmonary disease except bronchial asthma were studied. They were randomly put into the control group or a group which would be given oral treatments with an expectorant for a week after a one week washout period. The groups were as follows: Group I (n = 8 ), control; Group II (n = 7 ), Bromhexine hydrochloride 24 mg per day;…Group III (n = 10 ), Ambroxol 90 mg per day; Group IV (n = 9 ) α - Chymotrypsin buccle 100 ch.u. per day; Group V (n = 6 ), Serratiopeptidase 30 mg per day. In Groups IV & V, frequency dependence of sputum viscoelasticity at the range of ω = 10 − 3 to 10 − 0 rad.sec−1 were clearly changed after the treatments, and the magnitude of the relaxation and its main relaxation time were significantly increased. On the other hand, in Groups I, II & III, no significant changes of the frequency dependences were observed. These findings suggest that proteolytic enzymes administered orally work on the molecular structure of sputum, and break down their linkages between subunits of the structure.
Abstract: When viscoelasticity is measured with an oscillating capillary rheometer, the density of the fluid under study is an influencing factor (inertia). In the particular case of blood rheology hematocrit is also of interest. It can be measured more exactly on the basis of the density of blood and blood plasma than by conventional methods using a hematocrit centrifuge or Coulter counter, as these give too high readings when there is an increased tendency towards erythrocyte aggregation and reduced erythrocyte flexibility. Due to the double significance of blood density for blood viscoelasticity, an oscillating capillary rheometer and a new type of…density-measuring device were attached to a computer in such a way that simultaneous evaluation is possible. The density-measuring device is a U-tube that is set into oscillation electronically. The duration of the oscillation is an indication of the density of the fluid in the U-tube.
Abstract: Hemorheological studies were made on surface layers of solutions of highly purified human fibrinogen, to which low molecular weight (LMW) heparins, as well as chondroitins A, Band C were added. The surface viscous (η s ′ ) and elastic (G s ) moduli of these fibrinogen systems were measured with a modified Weissenberg Rheogoniometer. Our findings show that n s ′ and G s of these heparin-fibrinogen and chondroitin-fibrinogen surface systems were markedly decreased as compared…to the fibrinogen control. Heparin of MW 4400 exhibited about 30 per cent decrease, while heparins of MW 5300 and 5900 had decreases of approximately 75 per cent in n s ′ and G s . The three chondroitins A, Band C were found to reduce the n s ′ and G s by about 40 per cent. The surface layers of fibrinogen, which are surface gels, constitute the clotting of fibrinogen without thrombin participation. Such so-called ‘fibrinogenin’ formation is considered by Copley to initiate thrombosis. The LMW heparins and the chondroitins tested, which we found to inhibit fibrinogen formation, may therefore be expected to act as anti thrombotic agents. Thus, LMW heparins and chondroitins A, Band C may play important roles in the prevention of thrombosis.
Keywords: Antithrombotic action, chondroitin sulfate A, B and C, elastic modulus, fibrinogen clotting without thrombin, fibrinogen formation, fibrinogen surface layers, low molecular weight heparins, surface gels, thrombogenesis, viscous modulus, Weissenberg Rheogoniometer
vol. 20, no. 5, pp. 697-704, 1983
Abstract: Hydroxyethyl starch (RES) has often been used as a plasma expander, but questions still remain concerning the mechanism by which it produces changes in the rheological properties of blood and erythrocyte (RBC) suspensions under various flow conditions. The present investigation has shown that the dynamic viscosity of RES (232,000 and 565,000 daltons) solutions rises in a nonlinear fashion with increasing HES concentration, and for a given concentration of HES exhibits Newtonian behavior at shear rates between 0.15 to 124 −1 . At low (< 0.9 −1 ) shear rates the apparent viscosity of a 40% RBC suspension increases with lower…concentrations of HES because of RBC aggregation. At higher concentrations of RES, increases in suspension viscosity are due to an increase in the viscosity of the continuous phase since the RBC are largely disaggregated. At high (> 36 sec−1 ) shear rates the relative viscosity (η / η 0 ) of RBC suspensions slowly decreases with increasing HES concentration. At low shear rates η / η 0 increases and then decreases with increasing RES concentration. Evidence of the concentration-dependent effects of RES on RBC aggregation is provided not only by the viscometric analysis but also from measurements of erythrocyte sedimentation rate (ESR) and the zeta sedimentation ratio (ZSR). HES is a more potent aggregating agent in phosphate buffered saline (PBS) than it is in plasma. Polymer size has only a slight effect on the extent of RBC aggregation produced, but does have a significant effect on the concentration of polymer at which maximum aggregation occurs. The viscosity-corrected electrophoretic mobility of RBC in HES rises monotonically with the concentration of HES in the suspending medium. Decreases in the extent of RBC aggregation with increasing polymer concentrations probably result from an increase in the electrostatic repulsive forces between the cells.
Abstract: Separation flow through matrices or membranes is generally characterized by three phenomenological coefficients. Of these the hydraulic permeability Lp and the reflection coefficient σ are the most commonly discussed. Their theoretical interpretation is much aided by the use of friction coefficients f ˆ ℓ m defined to characterize the relative interaction in flow of the thermodynamic component ℓ in its movement past m. It is shown that this definition can be further simplified and that as a result simplified expressions notably for Lp result.