Search results for "STIFFNESS"
showing 10 items of 524 documents
Training-induced increase in Achilles tendon stiffness affects tendon strain pattern during running
2019
Background During the stance phase of running, the elasticity of the Achilles tendon enables the utilisation of elastic energy and allows beneficial contractile conditions for the triceps surae muscles. However, the effect of changes in tendon mechanical properties induced by chronic loading is still poorly understood. We tested the hypothesis that a training-induced increase in Achilles tendon stiffness would result in reduced tendon strain during the stance phase of running, which would reduce fascicle strains in the triceps surae muscles, particularly in the mono-articular soleus. Methods Eleven subjects were assigned to a training group performing isometric single-leg plantarflexion co…
Patient-specific computational evaluation of stiffness distribution in ascending thoracic aortic aneurysm
2021
Quantifying local aortic stiffness properties in vivo is acknowledged as essential to assess the severity of an ascending thoracic aortic aneurysm (ATAA). Recently, the LESI (local extensional stiffness identification) methodology has been established to quantify non-invasively local stiffness properties of ATAAs using electrocardiographic-gated computed tomography (ECG-gated CT) scans. The aim of the current study was to determine the most sensitive markers of local ATAA stiffness estimation with the hypothesis that direct measures of local ATAA stiffness could better detect the high-risk patients. A cohort of 30 patients (12 BAV and 18 TAV) referred for aortic size evaluation by ECG-gated…
Blends of Semiflexible Polymers: Interplay of Nematic Order and Phase Separation
2021
Mixtures of semiflexible polymers with a mismatch in either their persistence lengths or their contour lengths are studied by Density Functional Theory and Molecular Dynamics simulation. Considering lyotropic solutions under good solvent conditions, the mole fraction and pressure is systematically varied for several cases of bending stiffness κ (the normalized persistence length) and chain length N. For binary mixtures with different chain length (i.e., NA=16, NB=32 or 64) but the same stiffness, isotropic-nematic phase coexistence is studied. For mixtures with the same chain length (N=32) and large stiffness disparity (κB/κA=4.9 to 8), both isotropic-nematic and nematic-nematic unmixing oc…
Liver stiffness quantification in patients with non-alcoholic steatohepatitis: comparison of shear wave elastography and transient elastography with …
2019
Purpose: To assess the accuracy of liver stiffness quantification in patients with non-alcoholic steatohepatitis (NASH) using shear wave elastography (SWE) in comparison with transient elastography (TE). Methods and Materials: This is a prospective study performed in a single institution, including 49 patients with histological diagnosis of NASH. The stiffness of the right liver lobe was measured on the same day with two techniques: TE (FibroScan, Echosens), and SWE (RS80A ultrasound system, Samsung Medison). In the SWE evaluation, 11 patients were excluded due to more than 75% measurements fails. Receiver operating curves (ROC), areas under the ROC (AUROC) and 95% confidence intervals (CI)…
Liver stiffness quantification in biopsy-proven nonalcoholic fatty liver disease patients using shear wave elastography in comparison with transient …
2021
Purpose: This study prospectively assessed the performance of liver stiffness measurements using point shear-wave elastography (p-SWE) in comparison with transient elastography (TE) in patients with biopsy-proven nonalcoholic fatty liver disease (NAFLD). Methods: Fifty-six consecutive adult patients with a histological diagnosis of NAFLD prospectively underwent TE and p-SWE on the same day. The median of 10 measurements (SWE-10), the first five (SWE-5), and the first three (SWE-3) measurements were analyzed for p-SWE. Liver biopsy was considered as the reference standard for liver fibrosis grade. Receiver operating characteristic (ROC) curves and areas under the ROC curves (AUROCs) were cal…
Ankle-Brachial Index and Cardio-Ankle Vascular Index and their association with cardiorespiratory fitness and leisure-time physical activity in men w…
2017
Nilkka-olkavarsipainesuhteen ja verisuonten jäykkyyden yhteys hengitys- ja verenkiertoelimistön kuntoon sekä vapaa-ajan fyysiseen aktiivisuuteen tyypin 1 diabetesta sairastavilla miehillä. Johdanto. Tyypin 1 diabetesta sairastavilla valtimosairauksien riski on huomattavasti kohonnut verrattuna henkilöihin, joilla ei ole diabetesta. Fyysisen aktiivisuuden on osoitettu olevan yhteydessä matalampaan sydän- ja verisuonisairauksien riskiin, minkä takia fyysisen aktiivisuuden lisääminen voisi auttaa tyypin 1 diabeetikkojen sairastumisriskin hallitsemisessa. Tutkimuksen tarkoitus oli vertailla nilkka-olkavarsipainesuhdetta (ABI) ja valtimoiden jäykkyyttä CAVI-indeksillä mitattuna tyypin 1 diabetes…
Associations of cardiorespiratory fitness, physical activity, and BMI with arterial health in middle‐aged men and women
2020
We investigated the associations of cardiorespiratory fitness (CRF), physical activity (PA) with regard to aerobic and resistance training, and body mass index (BMI) with pulse wave velocity (PWV) and augmentation index (AIx) in middle‐aged adults with at least one cardiovascular risk factor. A total of 84 (46 men and 38 women) participated in the study. Cardiorespiratory fitness was measured using a maximal graded exercise test on a cycle ergometer and was defined as maximal power output (Wmax) normalized for body weight‐0.35. Participation in aerobic and resistance training was assessed by a detailed questionnaire and BMI was calculated as weight (kg)/[height (m2)]. Pulse wave velocity an…
Effects of heating, drying and straining on the relaxation and tensile properties of wet paper
2014
BEM analysis of a piezoelectric structural health monitoring system for delamination detection
2013
In the present work a piezoelectric based structural health monitoring (SHM) system is analyzed with the aim of assessing the ability of the piezoelectric patch to detect both edge and embedded delaminations proper of flange-skin composite laminated structures. he boundary element model is developed for piezoelectric solids and is implemented by taking advantage of the multidomain technique to model laminated and cracked configurations. A non-linear spring model interface is then implemented in conjunction with an iterative procedure allowing for the simulation of the finite stiffness of the bonding layers as well as of the non-penetration condition of the delamination surfaces. he dynamic …