Contractile properties of rabbit tibialis anterior muscles were measured after eccentric contraction to investigate the mechanism of muscle injury. In the first experiment, two groups of muscles were strained 25% of the muscle fiber length at identical rates. However, because the timing of the imposed length change relative to muscle activation was different, the groups experienced dramatically...

In this paper, a methodology for finite-element elastoplastic analyses of structures subjected to cyclic loading, based on a new form of endochronic {internal time) plasticity theory, is presented. In the present version of the endochronic theory, the rate forms of the stress/strain relations (stated here explicitly for plane stress, plane strain, and three-dimensional cases) are entirely analo...

Endothelial cell polarization and directional migration is required for angiogenesis. Polarization and motility requires not only local cytoskeletal remodeling but also the motion of intracellular organelles such as the nucleus. However, the physiological significance of nuclear positioning in the endothelial cell has remained largely unexplored. Here, we show that siRNA knockdown of nesprin-1,...

The various types of lactones have different durability and properties. The most stable among γ-lactones and δ-lactones, which are those containing respectively five or six carbon in the cyclic ring. The lowest durability can be attributed to α-lactones, due to the strong tension torsion and angle of bonds between the atoms forming the ring. Similar tension, to a lesser extent also observed in ...

The annulus fibrosus (AF) of the intervertebral disc experiences cyclic tensile loading in vivo at various states of mechanical equilibrium. Disc degeneration is associated with alterations in the biochemical composition of the AF including decreased water content, decreased proteoglycan concentration, and increased collagen deposition that affect mechanical function of the AF in compression an...

This study proposes a new tension member with buckling-free function using carbon fiber reinforced polymer for the seismic bracing system. Firstly, concept of composite brace; partially fibred brace, is introduced. Secondly, material strength brace molded by modified pultrusion investigated. Finally, cyclic loading tests to simulate are conducted. As result, it was demonstrated that system can ...

This work explores the monotonic and cyclic behaviors of filled, natural rubber. Results of stress-strain experiments conducted under stress states of simple, planar, and equibiaxial tension are presented. The ability of hyperelastic models to capture the observed response, as well as recent developments in constitutive modeling of filled rubber such as the consequences of the Mullins effect, a...

BACKGROUND No definite consensus has been reached regarding the optimal technique for graft fixation to the femur in an anterior cruciate ligament reconstruction. The purpose of this study was to evaluate the mechanical strength of two cortical suspension devices which were the TightRope (TR), a new adjustable-length loop device, and the EndoButton (EB), a well-established fixed-length loop dev...

We investigated a hypothesis that an oxygen sensor involved in hypoxia-induced relaxation of vascular smooth muscle may reside in endothelial cells. We also determined the oxygen dependence of hypoxia-induced decreases in cyclic guanosine 3',5'-monophosphate concentrations in vascular smooth muscle rings. Rings of canine femoral artery, rabbit thoracic aorta, and lamb ductus arteriosus, either ...

BACKGROUND This study was to investigate the effect of biomechanical stimulation on osteoblast differentiation of human periosteal-derived stem cell using the newly developed bioreactor. METHODS Human periosteal-derived stem cells were harvested from the mandible during the extraction of an impacted third molar. Using the new bioreactor, 4% cyclic equibiaxial tension force (0.5 Hz) was applie...