Glucocorticoids are known to induce osteocyte apoptosis, whereas mechanical loading has been shown to sustain osteocyte viability. Here we show that mechanical loading in the form of fluid-flow shear stress blocks dexamethasone-induced apoptosis of osteocyte-like cells (MLO-Y4). Prostaglandin E(2) (PGE(2) ), a rapidly induced signaling molecule produced by osteocytes, was shown to be protective...

This paper reports on an experimental and analytical investigation conducted into efficacy of the scraping shear-test method in estimating the shearing adhesive strength of a thermally sprayed coating. It was found that the critical average shear stress, the apparent failure strength of WC-Co thermal spray coating, depends on both the dimensions of the test piece and the loading position around...

The non-linear mechanical behaviour of porcine brain tissue in large shear deformations is determined. An improved method for rotational shear experiments is used, producing an approximately homogeneous strain field and leading to an enhanced accuracy. Results from oscillatory shear experiments with a strain amplitude of 0.01 and frequencies ranging from 0.04 to 16 Hz are given. The immediate l...

Although we rarely see a shock wave in everyday life, we experience them upon hearing the sound of an explosion, the bang of a gunshot, or the crack of a whip. In addition, objects that travel at supersonic speeds, such as bullets and missiles, also generate shock waves. During a typical shock-loading process, large pressures generated at the shock front can lead to an increase in the reactants...

The exemplary mechanical performance and durability of ultra-high performance concrete (UHPC) has led to its rapid emergence as an advanced cementitious material. The uncharacteristically high mechanical strength and ductility of UHPC makes it a promising potential material for defense structures which may be subject to highly dynamic loads like impact or blast. However, the mechanical response...

Accurate mechanical property data obtained at large shear deformations and high frequencies are a fundamental component of realistic numerical simulations of soft tissue injury. Although many commercial systems exist for testing shear properties of viscoelastic materials with properties similar to soft biological tissue, none are capable of determining properties at high loading rates necessary...

Understanding sub-Rayleigh-to-intersonic transition of mode II cracks is a fundamental problem in fracture mechanics with important practical implications for earthquake dynamics and seismic radiation. In the Burridge–Andrews mechanism, an intersonic daughter crack nucleates, for sufficiently high prestress, at the shear stress peak traveling with the shear wave speed in front of the main crack...

Carotid atherosclerotic disease is highly related to cerebrovascular events. Carotid endarterectomy is the common operation method to treat this disease. In this study, hemodynamics analyses are performed on the carotid arteries in three patients, whose right carotid artery had been treated by carotid endarterectomy and the left carotid artery remained untreated. Flow and loading conditions are...