Search results for " Saturation"
showing 10 items of 177 documents
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…
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…
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 …
Does Oxygen Concentration Used for Resuscitation Influence Outcome of Asphyxiated Newly Born Infants Treated With Hypothermia?
2006
To the Editor. — In a recent article, Rutherford et al1 describe the neuroprotective effect of whole-body cooling and selective head cooling in newly born infants suffering from hypoxic-ischemic encephalopathy. MRI studies of infants receiving either of these therapies showed a lesser degree of basal ganglia and thalamic lesions than nontreated controls, which correlates with a better neurologic prognosis. However, no description of the resuscitation maneuvers used is present in the article's “Patients and Methods” section. Thus, the authors do not include details on how many infants were given positive pressure ventilation and, especially, what concentration of oxygen was used, if oxygen s…
0126: 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 hepcidin-regulating hormone), transferrin …
Therapy with non-invasive ventilation in patients with obstructive sleep apnoea: effects on atherogenic lipoprotein phenotype.
2009
Patients with obstructive sleep apnoea are at increased risk of atherosclerotic morbidity and mortality. Abnormalities in lipid metabolism that occur in response to chronic intermittent hypoxia in patients with sleep-disordered breathing may increase the cardiovascular risk in an already susceptible population. Atherogenic lipoprotein phenotype and small, dense LDL have an independent predictive role for future cardio- and cerebro-vascular events in patients with the metabolic syndrome. Therefore, testing the hypothesis that therapy of obstructive sleep apnoea may reduce atherogenic lipoprotein phenotype might have significant clinical implications. We suggest that abolition of obstructive …
Impact of increased mean arterial pressure on skin microcirculatory oxygenation in vasopressor-requiring septic patients: an interventional study
2019
Abstract Background Heterogeneity of microvascular blood flow leading to tissue hypoxia is a common finding in patients with septic shock. It may be related to suboptimal systemic perfusion pressure and lead to organ failure. Mapping of skin microcirculatory oxygen saturation and relative hemoglobin concentration using hyperspectral imaging allows to identify heterogeneity of perfusion and perform targeted measurement of oxygenation. We hypothesized that increasing mean arterial pressure would result in improved oxygenation in areas of the skin with most microvascular blood pooling. Methods We included adult patients admitted to the intensive care unit within the previous 24 h with sepsis a…