Global left ventricular (LV) isovolumic relaxation rate has been characterized: 1) via the time constant of isovolumic relaxation τ or 2) via the logistic time constant τ(L). An alternate kinematic method, characterizes isovolumic relaxation (IVR) in accordance with Newton's Second Law. The model's parameters, stiffness E(k), and damping/relaxation μ result from best fit of model-predicted pres...

Because systole and diastole are coupled and systolic ventricular-vascular coupling has been characterized, we hypothesize that diastolic ventricular-vascular coupling (DVVC) exists and can be characterized in terms of relaxation and stiffness. To characterize and elucidate DVVC mechanisms, we introduce time derivative of pressure (dP/dt) vs. time-varying pressure [P(t)] (pressure phase plane, ...

to evaluate the acute effect of lovastatin on diabetic endothelial dysfunction, we examined this effect on the aortic rings of streptozotocin-diabetic rats. the endothelial function was assessed in aortic rings isolated from diabetic rats, 12 weeks after treatment with streptozotocin (45 mg/kg, i.p.). the concentration-response curve to acetylcholine (ach) in the aortic rings precontracted with...

The mechanical behavior of the heart muscle tissues is the central problem in finite element simulation of the heart contraction, excitation propagation and development of an artificial heart. Nonlinear elastic and viscoelastic passive material properties of the left ventricular papillary muscle of a guinea pig heart were determined based on in-vitro precise uniaxial and relaxation tests. The n...

conclusions relaxation with guided imagery had a positive effect on mediating anxiety and depression in breast cancer patients. results the experimental group showed significant decreases in insomnia (-0.34 ± 0.83, p < 0.05), pain (-0.28 ± 0.58, p < 0.05), anxiety (-3.56 ± 2.94, p < 0.00), and depression (-2.38 ± 2.70, p < 0.00) between the pretest and the posttest. comparing the two groups, st...

conclusion using standard imaging parameters, each mri sequence reaches its maximum si in a specific contrast concentration, which is highest in se and least in ir in a comparison between se, fse and ir sequences. results this study shows that maximum si will appear at different ranges in different sequences. the maximum si can be seen at concentrations of 5.95, 4.96 and 3.98mmol/l for se, fse ...

abstract background: concerning the prevalence of test anxiety among nursing students and presence of stress in nursing education years, this study was conducted to determine the effect of progressive muscle relaxation method on test anxiety among nursing students of isfahan university of medical sciences in 2013. materials and methods: this was a quasi-experimental study conducted in three sta...

To study spinal neuron function during relaxation imagery, we analyzed F-waves of the left thenar muscles in 15 healthy subjects (9 males, 6 females; mean age, 27.9 ± 9.2 years) after stimulating the left median nerve at the wrist. Fwaves were recorded in a resting position and during and after a 1-min period of relaxation imagery; they were recorded immediately after and at 5, 10, and 15 min a...

the internal mammary artery (ima) is currently the preferred conduit for myocardial revascularization. however, pre-operative vasospasm and a hypoperfusion state during maximal exercise may limit its use as a bypass graft. the mechanism of spasm has not been clearly defined. since β-adrenoceptor activation plays a major role in vasorelaxation, the present study was carried out to investigate th...

background: anxiety among patients after surgery can affect their physiological and psychological well-being. the aim of this study was to investigate and compare the effects of benson’s relaxation and rhythmic breathing techniques on postoperative anxiety in candidates for the mastectomy surgery. methods: this randomized controlled clinical trial study was conducted with ninety patients in 201...