Search results for " Elasticity"
showing 10 items of 147 documents
Diagnostic accuracy of elastography and magnetic resonance imaging in patients with NAFLD: A systematic review and meta-analysis
2021
[Background and Aims] Vibration-controlled transient elastography (VCTE), point shear wave elastography (pSWE), 2-dimensional shear wave elastography (2DSWE), magnetic resonance elastography (MRE), and magnetic resonance imaging (MRI) have been proposed as non-invasive tests for patients with non-alcoholic fatty liver disease (NAFLD). This study evaluated their diagnostic accuracy for liver fibrosis and non-alcoholic steatohepatitis (NASH).
Micro and Macro Resilience Measures of an Economic Crisis
2020
Using Italian Households Budget Survey data over the period 1997-2013, a Cragg model in a life-cycle context is specified to compare the consumption behaviour in the pre- and post-crisis time and develop different micro and macro measures of resilience against crisis shocks. Cohort profiles for participation in and for consumption of tourism services in the pre- and post-crisis time are determined so as to explore the households’ resilience by generations. Next, the households’ resilience according to socio-demographic characteristics is addressed. As for the macro-resilience, combining individual expenditure elasticity, we examine whether and how Italian regions have responded to the recen…
Optimising management of patients with hepatitis C virus in the age of direct-acting antivirals: results of a Delphi consensus.
2018
OBJECTIVE: To optimize the management of patients with chronic hepatitis C virus (HCV). MATERIALS AND METHODS: We developed two questionnaires to determine Italian healthcare professionals’ opinions on the overall management of HCV chronic liver disease and the use of direct-acting antivirals (DAAs) in the treatment of HCV. A Delphi consensus method using the RAND/UCLA appropriateness method was used to determine opinions of an expert panel (EP) of specialists. RESULTS: Overall 443 physicians from 167 Italian centres completed the two questionnaires. The EP confirmed the importance of collaboration with general practitioners (GPs) and HCV testing in high-risk groups, but did not agree on tr…
Prospective comparison of Fibroscan, King's score and liver biopsy for the assessment of cirrhosis in chronic hepatitis C infection
2010
Historically, liver biopsy (LB) was the sole method to evaluate the severity of hepatic fibrosis in patients with chronic hepatitis C infection. However, LB is expensive and associated with a risk of severe complications. Therefore, noninvasive tests have been developed to assess the severity of liver fibrosis. The accuracy of Fibroscan (FS) and King's score (KS) was evaluated individually and in combination using liver histology as the reference standard. One hundred and eighty-seven patients were identified who had undergone a biopsy with a diagnosis of chronic hepatitis C virus (HCV) mono-infection (HCV RNA-positive by RT-PCR), attending King's College Hospital (n = 88) or the Royal Free…
Fibrosis staging in chronic hepatitis C: Analysis of discordance between transient elastography and liver biopsy
2009
Summary. In chronic hepatitis C, transient elastography (TE) accurately identifies cirrhosis, but its ability to assess significant fibrosis (Metavir ≥ F2) is variable. Constitutional and liver disease-related factors may influence TE and here we examined the variables associated with differences. Three hundred consecutive hepatitis C virus (HCV)-RNA positive patients had biochemical tests, TE and a biopsy performed on the same day. The Dale model was used to identify the variables associated with discordance between biopsy and elastography results. In 97 patients (34.2%), TE and histological assessment were discordant. Seventy-six of 286 (26.6%) had stage ≥F2 and TE < 7.1 kPa (false negat…
A second strain gradient elasticity theory with second velocity gradient inertia – Part II: Dynamic behavior
2013
Abstract This paper is the sequel of a companion Part I paper devoted to the constitutive equations and to the quasi-static behavior of a second strain gradient material model with second velocity gradient inertia. In the present Part II paper, a multi-cell homogenization procedure (developed in the Part I paper) is applied to a nonhomogeneous body modelled as a simple material cell system, in conjunction with the principle of virtual work (PVW) for inertial actions (i.e. momenta and inertia forces), which at the macro-scale level takes on the typical format as for a second velocity gradient inertia material model. The latter (macro-scale) PVW is used to determine the equilibrium equations …
A gradient elasticity theory for second-grade materials and higher order inertia
2012
Abstract Second-grade elastic materials featured by a free energy depending on the strain and the strain gradient, and a kinetic energy depending on the velocity and the velocity gradient, are addressed. An inertial energy balance principle and a virtual work principle for inertial actions are envisioned to enrich the set of traditional theoretical tools of thermodynamics and continuum mechanics. The state variables include the body momentum and the surface momentum, related to the velocity in a nonstandard way, as well as the concomitant mass-accelerations and inertial forces, which do intervene into the motion equations and into the force boundary conditions. The boundary traction is the …
A strain-difference-based nonlocal elasticity model
2004
Abstract A two-component local/nonlocal constitutive model for (macroscopically) inhomogeneous linear elastic materials (but constant internal length) is proposed, in which the stress is the sum of the local stress and a nonlocal-type stress expressed in terms of the strain difference field, hence identically vanishing in the case of uniform strain. Attention is focused upon the particular case of piecewise homogeneous material. The proposed model is thermodynamically consistent with a suitable free energy potential. It constitutes an improved form of the Vermeer and Brinkgreve [A new effective nonlocal strain measure for softening plasticity. In: Chambon, R., Desrues, J., Vardulakis, I. (E…
Study on Experimental Determination of the Elasticity Modulus of Casted Basalt
2020
Basalt is a material available in big quantities in nature. It has a low price and can be used in various domains. It can be relatively easily extracted from natural deposits and processed by means of melting. Melted and recrystallized basalt has demonstrated promising behavior with regards of its use in manufacturing, as reported in the literature. This paper presents the results of an experimental study on the determination of the modulus of elasticity of molten and recrystallized basalt by the method of resistive electrical tensometry and to validate the result and by simulation using finite elements method. Testing methodology, experimental test, data records, data processing and result…
Including Ratio of Platelets to Liver Stiffness Improves Accuracy of Screening for Esophageal Varices That Require Treatment
2021
International audience; Background & aims: Based on platelets and liver stiffness measurements, the Baveno VI criteria (B6C), the expanded B6C (EB6C), and the ANTICIPATE score can be used to rule out varices needing treatment (VNT) in patients with compensated chronic liver disease. We aimed to improve these tests by including data on the ratio of platelets to liver stiffness.Methods: In a retrospective analysis of data from 10 study populations, collected from 2004 through 2018, we randomly assigned data from 2368 patients with chronic liver disease of different etiologies to a derivation population (n = 1579; 15.1% with VNT, 50.2% with viral hepatitis, 28.9% with nonalcoholic fatty liver …