Viscoelastic models can be used to better understand arterial wall mechanics in physiological and pathological conditions. The arterial wall reveals very slow time-dependent decays in uniaxial stress-relaxation experiments, coherent with weak power-law functions. Quasi-linear viscoelastic (QLV) theory was successfully applied to modeling such responses, but an accurate estimation of the reduced...

Behavioral stress and aging are associated with an increase in vascular disease. This study determined the mechanisms contributing to changes in endothelium-dependent relaxation of isolated coronary arteries (300-350 μm) induced by exposure to 10 days of air-jet stress (2 h/day) in young (3 mo) and old (18 mo) male borderline hypertensive rats (BHR). Aging, alone, did not alter endothelium-depe...

BACKGROUND Prenatal maternal stress is associated with adverse birth outcomes. Relaxation techniques might be effective in reducing stress during that period. The purpose of this study was to evaluate the effects of applied relaxation in reducing anxiety and stress in pregnant women in their second trimester, as well as raising their sense of control. Also we expected to see a difference in som...

To realize the high-efficiency and high-performance manufacture of complex high-web panels, this paper introduced electric pulse current (EPC) into the stress relaxation aging forming process of 2219 aluminum alloy and systematically studied the effects of EPC, stress, and aging time upon the microstructure and properties of 2219 aluminum alloy. It is discovered that: (a) EPC greatly enhanced t...

The relation of impaired left ventricular relaxation, as measured by prolonged isovolumic relaxation time, to ventricular systolic function in hypertension remains uncertain in population-based samples. In the Hypertension Genetic Epidemiology Network (HyperGEN) Study, echocardiograms were analyzed in 1457 hypertensive participants without diabetes, >/=2+ valvular regurgitation, or coronary dis...

The relation of impaired left ventricular relaxation, as measured by prolonged isovolumic relaxation time, to ventricular systolic function in hypertension remains uncertain in population-based samples. In the Hypertension Genetic Epidemiology Network (HyperGEN) Study, echocardiograms were analyzed in 1457 hypertensive participants without diabetes, $21 valvular regurgitation, or coronary disea...

Natural extracellular matrices (ECMs) are viscoelastic and exhibit stress relaxation. However, hydrogels used as synthetic ECMs for three-dimensional (3D) culture are typically elastic. Here, we report a materials approach to tune the rate of stress relaxation of hydrogels for 3D culture, independently of the hydrogel's initial elastic modulus, degradation, and cell-adhesion-ligand density. We ...

We report a dynamical-mechanical study of stress relaxation at small deformation in a natural (polyisoprene) rubber well above its glass transition temperature Tg. We find that an almost complete relaxation of stress takes place over very long relaxation periods, even though the elastic network is retained. The relaxation rate and the long-time equilibrium modulus are sensitive functions of tem...

Glass relaxation occurs in a range of temperature during transition from equilibrium to super-cooled liquid. Viscoelastic material model can be applied to simulate glass behavior in the glass transition regime. COMSOL Multiphysics software 4.3b can simulate the stress relaxation with the WLF (WilliamsLandel-Ferry) shift function, but no structural relaxation. In this study we developed a framew...