A minimal model for studying the mechanical properties of amorphous solids is a disordered network of point masses connected by unbreakable springs. At a critical value of its mean connectivity, such a network becomes fragile: it undergoes a rigidity transition signaled by a vanishing shear modulus and transverse sound speed. We investigate analytically and numerically the linear and nonlinear ...

With the use of micromanipulation techniques, the shear modulus or "rigidity" mu, the recovery time tc, and the unfolding time tf for individual sickle cells have been measured at different oxygen tensions, temperatures, and cell densities. In these experiments, the partial pressure of oxygen was varied from 156 to 40 mm Hg and the temperature was controlled at 25 degrees C or 37 degrees C. Thr...

We investigated the mechanical properties of two abundant, cytoplasmic proteins from Acanthamoeba, profilin and actin, and found that while both profilin and nonfilamentous actin alone behaved as solids, mixtures of the two proteins were viscoelastic liquids. When allowed to equilibrate, profilin formed a viscoelastic solid with mechanical properties similar to filamentous and nonfilamentous ac...

Beside pulsatile motion of vessel, there are two additional movements of coronary arteries. One is from the pulsatile momentum of coronary artery while dampened by the supporting soft tissues. Another movement is responsible by contracting myocardium throughout the cardiac cycle with part of epicardial artery tethered to myocardium. In this study, four different external boundary conditions of ...

We describe experimental studies of the deformation of giant lipid bilayer vesicles in shear flow. The experiments are carried out with a counterrotating Couette apparatus. The deformation depends on the mechanical properties of the lipid bilayer, the vesicle radius, and the viscosity of the surrounding Newtonian liquid. We show that the relevant mechanical parameter is the bending rigidity. A ...

The joints between segmental rings can withstand a certain amount of bending moment as well as axial and shear forces. Generally, in the structural analysis of tunnel segmental lining, the joints can be modeled as elastic hinges or rotational springs, and their rigidity should be demonstrated in terms of the rigidity of the joints or their rotational stiffness. Therefore, the bending moment act...

Background: The aim of this article is to introduce a novel technique of limited dynamic hip screw (LDHS) in the treatment of intertrochanteric fractures and to evaluate its biomechanical effects. Material/Methods: Based on the principle of providing both dynamic and static pressure to stabilize the fracture, we improved the dynamic hip screw (DHS) and designed the LDHS. Six fresh cadavers were...

Barbut, S. and Mittal, G. S. 1989. Effects of salt and fat reduction on the rheological and gelation properties of turkey meat batters. Can. Agric. Eng. 31: 271-277. The gelation and rheological proper ties of turkey meat batters prepared with two fat levels (16 and 23%) and three salt levels (2.5% NaCl, 1.75% NaCl, 1.75% NaCl + 0.4% hexametaphosphate (HMP)) were studied. The relationship betwe...

We investigated rheological adaptation of leukocytes and platelets for their adhesive functions in inflammation and hemostasis, respectively. Adhesion and margination of leukocytes or platelets were quantified for blood perfused through capillaries coated with P-selectin or collagen, when flow rate, suspending phase viscosity, red cell aggregation, or rigidity was modified. Independent variatio...