Search results for "saturation"
showing 10 items of 478 documents
Short-Term Outcomes of Patients With COVID-19 Undergoing Invasive Mechanical Ventilation: A Retrospective Observational Study From Wuhan, China.
2020
Background: COVID-19 has spread rapidly worldwide. Many patients require mechanical ventilation. The goal of this study was to investigate the clinical course and outcomes of patients with COVID-19 undergoing mechanical ventilation and identify factors associated with death. Methods: Eighty-three consecutive critically ill patients with confirmed COVID-19 undergoing invasive mechanical ventilation were included in this retrospective, single-center, observational study from January 31 to March 15, 2020. Demographic, clinical, laboratory, radiological, and mechanical ventilation data were collected and analyzed. The primary outcome was 28-day mortality after endotracheal intubation. The secon…
Hydro-mechanical analysis of volcanic ash slopes during rainfall
2016
Rainfall-induced landslides in volcanic ashes represent a major natural hazard in many regions around the world. Owing to their loose structure, volcanic ash slopes are prone to rainfall-induced landslides. The paper presents a continuum modelling approach for the analysis of wetting-induced instability phenomena at the onset of failure in loose volcanic ash slopes. A numerical simulation of a landslide-prone volcanic slope in Costa Rica is carried out with a two-dimensional hydro-mechanical finite-element slope model. A constitutive model based on the effective stress concept extended to partially saturated conditions is used to reproduce the volcanic ash hydro-mechanical behaviour. The m…
Yielding of a quartz sand from saturated to dry state
2020
The paper presents the results of an experimental work where we analyse the behaviour of an unsaturated quartz sand in a wide range of degree of saturation (from saturated to dry state). The possibility of anticipating the hydro-mechanical behaviour of the soils when they approach the dry state is fundamental in many areas. An extensive experimental program, including controlled-suction and constant water content oedometric tests, was carried out to deeply analyse the water retention behaviour and the relationship between the yield stress and suction (Loading-Collapse curve). All elasto-plastic models provide a monotonically increase of the yield stress with suction. This assumption implies…
Effects of hydrogen-charging on the properties of S235JR steel
2017
The paper presents the test results of the S235JR steel susceptibility to damage under the influence of hydrogen. The test of mechanical properties was performed on the basis of a static stretch test of non-hydrogenated samples and after cathodic polarization. Electrochemical measurements for the assessment of corrosion resistance of non-hydrogenated and hydrogenated steels were carried out using open circuit potential measurement and registering of potentiodynamic polarization curves in a three-electrode measuring system. Hydrogenation was carried out for between 3 and 24 hours in a solution of 0.1 N sulfuric acid (VI) with the addition of 2 mg/dm 3 of arsenic oxide (III) at an electric cu…
Suction controlled drying and wetting cycle effects on the volumetric behaviour of a lime-treated high plasticity clay
2016
The paper presents some experimental results collected on samples recovered from an experimental embankment obtained by compacting a lime-treated clay. Samples were collected soon after the in situ compaction and they were cured in controlled environmental conditions for at least 18 months. Mercury intrusion porosimetry tests (MIP) were carried out on freeze-dried specimens to characterize the microstructure of the material. In order to assess the durability of the improved material, laboratory tests focused on the effects of cyclic variations of the degree of saturation on the water retention properties and the volumetric behaviour of the stabilized clay. Collected results show that the li…
Hydro-mechanical behaviour of a sandy silt from a river embankment
2020
The paper presents the results of an experimental campaign aimed at characterizing the hydro-mechanical behaviour of a sandy silt from a river embankment. Due to continuous river level fluctuations and changing climatic and environmental conditions, flood embankment materials experience frequent variations in degree of saturation and suction values. Such variations strongly impact the earthwork performance both in terms of seepage and stability conditions. For these reasons, a detailed characterization of the material behaviour in unsaturated conditions was carried out. Experiments were designed in order to highlight the response of the involved soil in terms of changes in matric suction an…
Bestimmung der myokardialen Perfusionsreserve bei KHK-Patienten mit der kontrastmittelverstärkten MRT: Ein Vergleich zwischen semiquantitativer und q…
2002
OBJECTIVE Comparison between two semiquantitative methods and a quantitative evaluation of myocardial blood flow (MBF) for assessment of myocardial perfusion reserve (MPR) in patients with CAD. MATERIAL AND METHODS 9 patients with coronary stenoses > 50 % were examined with an ECG-gated Saturation Recovery Turbo FLASH sequence by using Gd-DTPA as contrast agent (CA). The entive measurements were performed both during rest and hyperemia induced by adenosine. The up-slopes of the signal-time S(t) curves in the myocardium and left ventricular (LV) cavity were evaluated by a linear fit. MPR was calculated from the original up-slopes of the myocardial S(t) curves and from the up-slopes, which we…
0135 : New regulators of iron metabolism, hepcidin and erythroferrone, in acute myocardial infarction
2016
Background Dysfunctional iron storage and transport are common in patients with chronic heart failure and associated with poor prognosis. Body iron could contribute to the pathogenesis of coronary artery disease (CAD) through its ability to induce oxidative stress. However, studies on the relationship between iron metabolism and CAD have yielded conflicting results. Patients and methods from the obseRvatoire des Infarctus de Cote d’Or (RICO) survey, 31 consecutive patients admitted in Intensive Care Unit for a first AMI were included. Serum concentrations of iron, transferrin, ferritin, the iron-regulatory hormone hepcidin and erythroferrone (a new hepcidinregulating hormone), transferrin s…
Iron deficiency and long-term mortality in elderly patients with acute coronary syndrome.
2018
Aim: We evaluated the relationship between iron deficiency (ID) and long-term mortality risk in elderly patients with acute coronary syndrome (ACS). Methods: In this prospective observational study, we included 252 patients older than 65 years with ACS. Transferrin saturation (TSAT) and ferritin were collected before discharge. Results: Mean age, hemoglobin and GRACE score were 78 ± 7 years, 12.4 ± 1.8 g/dl and 138.8 ± 25.3, respectively, 112(44.4%) patients were women, and 151(59.9%) presented ID. During the follow-up, 121 (48%) patients died. Mortality rates among TSAT quartiles were: 2.38, 1.60, 0.90 and 0.95 × 10 person-years for Q1TSAT to Q4TSAT, respectively (p < 0.001) and did no…
Reference values for mean overnight saturation in sleep apnoea – the European Sleep Apnoea Database (ESADA)
2020
Introduction: Normative values for mean overnight oxygen saturation during sleep in apnoea patients stratified for age, BMI, and sleep apnoea severity are lacking. Aim: To establish reference intervals for overnight mean saturation in a large sleep apnoea patient cohort. Methods: Mean overnight oxygen saturation was analysed in adult patients (n=23,220) from the European Sleep Apnoea Database (ESADA, 30 sleep centres, 18 European countries). Data were classified according to age, gender, BMI ( Results: Mean overnight saturation was 93.0% (95% confidence interval (CI) 92.9 to 93.1%). Age influenced the adjusted mean nocturnal saturation (93.6%, 93.2%, 92.9%, 92.5%, 92.2% and 91.9% for those …