Search results for "stiffne"
showing 10 items of 533 documents
Competition between liquid-crystalline ordering and glassy freezing in melts of semiflexible polymers: A monte carlo simulation
1999
We present results of a Monte Carlo simulation of dense melts of semiflexible polymers using the bond-fluctuation model. The chosen Hamiltonian increases the chain stiffness upon cooling which in turn leads to glass-transition like freezing of the polymer mobility. Employing an efficient simulation algorithm, which is able to equilibrate the simulated systems to lower temperature than the Rouse-type algorithm showing the glassy freezing, we are able to observe an isotropic-nematic phase transition. This transition lies above the glass transition temperature one would extrapolate from the observed freezing behavior.
Photoplethysmography Analysis of Artery Properties in Patients with Cardiovascular Diseases
2008
In this study arterial parameters of healthy subjects were compared to those of patients with cardiovascular diseases. The photoplethysmography (PPG) measurements of blood volume pulsations have been performed. Using a novel algorithm for analysis of simultaneously measured ear and finger PPG signals, arterial parameters were evaluated in representative groups of healthy subjects and patients with cardiovascular diseases. Digital volume pulse (DVP), pulse cycle duration (T), augmentation index (AIx), reflection index (RI) and transit time of reflected wave (RTT) were evaluated in every heartbeat cycle. Correlations between the AIx and RI, T and RTT, AIx and standard deviation of AIx, RTT an…
Peripheral Nerve Responses to Muscle Stretching: A Systematic Review
2021
Stretching is commonly used to increase range of motion and flexibility. Therefore, investigations are usually oriented towards the muscle-tendon unit. Limited evidence exists regarding potential effects of stretching on peripheral nerves which lie within muscles. The objective of this investigation will be to elucidate the responses of peripheral nerves to stretching. A literature search was performed using the following databases: Scopus, NLM Pubmed and ScienceDirect. Studies regarding the effects of stretching protocols on responses of peripheral nerves were retrieved for investigation. The NHLBI tool was used for quality assessment. Outcomes included nerve stiffness, nerve displacement,…
Generalized curved beam on elastic foundation solved by Transfer Matrix Method
2011
A solution of space curved bars with generalized Winkler soil found by means of Transfer Matrix Method is presented. Distributed, concentrated loads and imposed strains are applied to the beam as well as rigid or elastic boundaries are considered at the ends. The proposed approach gives the analytical and numerical exact solution for circular beams and rings, loaded in the plane or perpendicular to it. A well-approximated solution can be found for general space curved bars with complex geometry. Elastic foundation is characterized by six parameters of stiffness in different directions: three for rectilinear springs and three for rotational springs. The beam has axial, shear, bending and tor…
Functional muscle architecture in aging
2014
Reliability of liver stiffness measurement in non-alcoholic fatty liver disease: the effects of body mass index.
2011
Background Liver stiffness measurement (LSM) using transient elastography (TE) is used to stage fibrosis in patients with liver disease, diagnostic reliability and the factors affecting its performance in patients with non-alcoholic fatty liver disease (NAFLD) are incompletely understood. Aim To assess LSM. Methods Consecutive NAFLD patients (n = 169), assessed by liver biopsy (Kleiner score), anthropometrical, biochemical and metabolic features, underwent LSM using TE with standard M probe. Results Liver stiffness measurement was not reliable in 23 patients (14%) due to obesity. Among patients with a reliable TE, a LSM value >7.25 kPa was the best cut-off for predicting significant fibrosi…
THE ROLE OF TRANSIENT ELASTOGRAPHY IN NAFLD
2021
N/A
Free vibrations analysis of cracked variable stiffness composite plates by the eXtended Ritz method
2022
Variable stiffness composite laminates show advantageous structural features related to their enlarged design space. They are attractive candidates for advanced engineering applications where the assessment of static and dynamic behavior and strength in the presence of cracks is often required. In the present work, a single-domain extended Ritz formulation is proposed to study the free vibrations of cracked variable stiffness composite plates. The plate model is based on the first-order shear deformation theory whose primary variable, i.e. displacements and rotations, are approximated via a set of orthogonal polynomial trial functions enriched with a set of special crack functions. These fu…
Peak oxygen uptake, ventilatory threshold, and arterial stiffness in adolescents
2018
Purpose To investigate the associations of peak oxygen uptake (V̇ O2peak) and V̇ O2 at ventilatory threshold (V̇ O2 at VT) with arterial stiffness in adolescents. Methods The participants were 55 adolescents (36 girls, 19 boys) aged 16–19 years. Aortic pulse wave velocity (PWVao) and augmentation index (AIx%) were measured by non-invasive oscillometric device from right brachial artery level. V̇ O2peak was directly measured during a maximal ramp test on a cycle ergometer. V̇ O2 at VT was determined using the equivalents for ventilation (V̇ E/V̇ CO2 and V̇ E/V̇ O2). V̇ O2peak and V̇ O2 at VT were normalised for body mass (BM) and lean mass (LM). Data were analysed using linear regression ana…