Search results for "Transient"
showing 10 items of 623 documents
‘Dry’ electrochemistry: A non-invasive approach to the characterization of archaeological iron objects
2021
A methodology for monitoring the corrosion state of archaeological iron objects using ‘dry’ open circuit potential (OCP) measurements is described. Application of this technique to a set of objects from La Bastida de les Alcusses archaeological site (Moixent, València, Spain), dating back to the 4th century BCE, reveals significant differences depending on the conservation state. The transient OCP responses (which last between a few seconds and 10–15 min) were superimposed with much shorter (less than one second) intense features. Fil: Doménech Carbó, Antonio. Universidad de Valencia; España Fil: Peiró Ronda, María Amparo. Museu de Prehistòria de València; España Fil: Vives Ferrándiz, Jaime…
THE ROLE OF NON-GAUSSIAN SOURCES IN THE TRANSIENT DYNAMICS OF LONG JOSEPHSON JUNCTIONS
2013
We analyze the effects of different non-Gaussian noise sources on the transient dynamics of an overdamped long Josephson junction. We find nonmonotonic behavior of the mean escape time as a function of the noise intensity and frequency of the external driving signal for all the noise sources investigated.
Sensitive magnetometry reveals inhomogeneities in charge storage and weak transient internal currents in Li-ion cells
2020
The ever-increasing demand for high-capacity rechargeable batteries highlights the need for sensitive and accurate diagnostic technology for determining the state of a cell, for identifying and localizing defects, and for sensing capacity loss mechanisms. Here, we leverage atomic magnetometry to map the weak induced magnetic fields around Li-ion battery cells in a magnetically shielded environment. The ability to rapidly measure cells nondestructively allows testing even commercial cells in their actual operating conditions, as a function of state of charge. These measurements provide maps of the magnetic susceptibility of the cell, which follow trends characteristic for the battery materia…
Numerical and experimental study of liquid metal stirring by rotating permanent magnets
2018
In this work, we study liquid gallium stirring by rotating permanent magnets. We demonstrate possibility of easily creating different flow patterns by rotating permanent magnets, which can be industrially important for controlling heat and mass transfer processes in the system. Unlike the typical approach of simulating magnet rotation as a transient problem and time-averaging the Lorentz forces, we solve the magnet rotation as a harmonic (frequency domain) problem, which leads to forces equal to time-averaged ones and decreases the simulation time considerably. Numerical results are validated using qualitative flow structure results from the neutron radiography visualization of tracer parti…
Liver Fibrosis and Metabolic Alterations in Adults With alpha-1-antitrypsin Deficiency Caused by the Pi*ZZ Mutation
2019
Background & Aims Alpha-1 antitrypsin deficiency (AATD) is among the most common genetic disorders. Severe AATD is caused by a homozygous mutation in the SERPINA1 gene that encodes the Glu342Lys substitution (called the Pi*Z mutation, Pi*ZZ genotype). Pi*ZZ carriers may develop lung and liver diseases. Mutation-associated lung disorders have been well studied, but less is known about the effects in liver. We assessed the liver disease burden and associated features in adults with this form of AATD. Methods We collected data from 554 Pi*ZZ adults (403 in an exploratory cohort, 151 in a confirmatory cohort), in 9 European countries, with AATD who were homozygous for the Pi*Z mutation, and 234…
Diagnostic accuracy of non-invasive tests for advanced fibrosis in patients with NAFLD : an individual patient data meta-analysis
2021
ObjectiveLiver biopsy is still needed for fibrosis staging in many patients with non-alcoholic fatty liver disease. The aims of this study were to evaluate the individual diagnostic performance of liver stiffness measurement by vibration controlled transient elastography (LSM-VCTE), Fibrosis-4 Index (FIB-4) and NAFLD (non-alcoholic fatty liver disease) Fibrosis Score (NFS) and to derive diagnostic strategies that could reduce the need for liver biopsies.DesignIndividual patient data meta-analysis of studies evaluating LSM-VCTE against liver histology was conducted. FIB-4 and NFS were computed where possible. Sensitivity, specificity and area under the receiver operating curve (AUROC) were c…
Non-invasive assessment of liver steatosis and fibrosis in HIV/HCV- and HCV- infected patients
2013
BACKGROUND: Conflicting data have been reported on the prevalence of liver steatosis, its risk factors and its relationship with fibrosis in patients with human immunodeficiency virus (HIV)/hepatitis C virus (HCV) co-infection or with HCV mono-infection. AIM: The study aims were to assess steatosis prevalence and its risk factors in both HCV groups. We also evaluated whether steatosis was linked with advanced fibrosis. Sixty-eight HIV/HCV co-infected and 69 HCV mono-infected patients were consecutively enrolled. They underwent liver ultrasonography and transient elastography. Bright liver echo-pattern was used to diagnose steatosis; advanced fibrosis was defined as liver stiffness ≥ 9.5 kPa…
Serological Tests Do Not Predict Residual Fibrosis in Hepatitis C Cirrhotics with a Sustained Virological Response to Interferon
2016
BACKGROUND AND AIM: Liver biopsy (LB) has lost popularity to stage liver fibrosis in the era of highly effective anti-hepatitis C virus (HCV) therapy, yet diagnosis of persistent cirrhosis may have important implications following HCV eradication. As performance of serological non-invasive tests (NITs) to predict residual fibrosis in non-viremic HCV patients is unknown, we investigated accuracy of NITs to predict residual fibrosis in cirrhotics after a sustained virological response (SVR) to interferon (IFN). METHODS: Thirty-eight patients with a pre-treatment histological diagnosis of cirrhosis and a 48–104 months post-SVR LB were tested with APRI, CDS, FIB-4, FibroQ, Forns Score, GUCI Ind…
Significant liver fibrosis assessed using liver transient elastography is independently associated with low bone mineral density in patients with non…
2017
Background Metabolic bone disorders frequently occur in patients with chronic liver disease; however, the association between liver fibrosis and bone mineral density in patients with non-alcoholic fatty liver disease (NAFLD) is unclear. Methods This is a cross-sectional analysis of 231 asymptomatic subjects (160 women, 61.6 years old) from a university hospital setting, between February 2012 and December 2014. Bone mineral density (BMD) was measured at the lumbar spine, femur neck, and total hip using dual-energy X-ray absorptiometry (DXA). Liver fibrosis and steatosis were assessed using transient elastography. Results Among a total of 231 individuals, 129 subjects (55.8%) had NAFLD. BMDs …
Prospective evaluation of hepatic steatosis in HIV-infected patients with or without hepatitis C virus co-infection
2012
Background: Limited data are available on hepatic steatosis (HS) in HIV patients who are not infected with hepatitis C virus (HCV). The aims of this study were to assess the prevalence of HS and its risk factors in HIV patients with and without HCV infection, and to evaluate whether HS correlates with advanced liver fibrosis and/or cardiovascular disease risk. Methods: Fifty-seven HIV mono-infected and 61 HIV/HCV co-infected patients were enrolled consecutively. All patients underwent liver ultrasound and transient elastography. The main parameters of liver function, HIV and HCV viral loads, CD4+ cell counts, and data on highly active antiretroviral therapy (HAART) were recorded. Cardiovasc…