Our study concerns the propagation of acoustic waves through a thin screen made of a periodic arrangement of air bubbles in water. The bubbles are oscillators of the Minnaert type whose dynamics is ...modified by the containment. This nonlinear dynamics is obtained in the time domain using asymptotic analysis and a homogenization technique involving three scales, those being the scale of a bubble, that of the array and eventually that of the wavelength. The resulting effective model is set in the water (the screen has disappeared) and it encapsulates the effect of the screen in a jump of the normal acoustic velocity. The jump is linked to the continuous version of the bubble radius which satisfies an equation of the Rayleigh–Plesset type. This allows us to highlight two important effects. Firstly, a bubble within the array has a much larger radiative damping than an isolated bubble. Secondly it perceives a pressure which differs from the acoustic pressure imposed by the source due to bubble–bubble interactions; it results in a term of mass correction deduced from the Green's function for a Laplace problem which accounts for the bubble arrangement. Our findings are exemplified by numerical experiments of the scattering of a short pulse in the linear and nonlinear regimes.
Septic shock is characterized by dysregulation of the host response to infection, with circulatory, cellular, and metabolic abnormalities. We hypothesized that therapy with hydrocortisone plus ...fludrocortisone or with drotrecogin alfa (activated), which can modulate the host response, would improve the clinical outcomes of patients with septic shock.
In this multicenter, double-blind, randomized trial with a 2-by-2 factorial design, we evaluated the effect of hydrocortisone-plus-fludrocortisone therapy, drotrecogin alfa (activated), the combination of the three drugs, or their respective placebos. The primary outcome was 90-day all-cause mortality. Secondary outcomes included mortality at intensive care unit (ICU) discharge and hospital discharge and at day 28 and day 180 and the number of days alive and free of vasopressors, mechanical ventilation, or organ failure. After drotrecogin alfa (activated) was withdrawn from the market, the trial continued with a two-group parallel design. The analysis compared patients who received hydrocortisone plus fludrocortisone with those who did not (placebo group).
Among the 1241 patients included in the trial, the 90-day mortality was 43.0% (264 of 614 patients) in the hydrocortisone-plus-fludrocortisone group and 49.1% (308 of 627 patients) in the placebo group (P=0.03). The relative risk of death in the hydrocortisone-plus-fludrocortisone group was 0.88 (95% confidence interval, 0.78 to 0.99). Mortality was significantly lower in the hydrocortisone-plus-fludrocortisone group than in the placebo group at ICU discharge (35.4% vs. 41.0%, P=0.04), hospital discharge (39.0% vs. 45.3%, P=0.02), and day 180 (46.6% vs. 52.5%, P=0.04) but not at day 28 (33.7% and 38.9%, respectively; P=0.06). The number of vasopressor-free days to day 28 was significantly higher in the hydrocortisone-plus-fludrocortisone group than in the placebo group (17 vs. 15 days, P<0.001), as was the number of organ-failure-free days (14 vs. 12 days, P=0.003). The number of ventilator-free days was similar in the two groups (11 days in the hydrocortisone-plus-fludrocortisone group and 10 in the placebo group, P=0.07). The rate of serious adverse events did not differ significantly between the two groups, but hyperglycemia was more common in hydrocortisone-plus-fludrocortisone group.
In this trial involving patients with septic shock, 90-day all-cause mortality was lower among those who received hydrocortisone plus fludrocortisone than among those who received placebo. (Funded by Programme Hospitalier de Recherche Clinique 2007 of the French Ministry of Social Affairs and Health; APROCCHSS ClinicalTrials.gov number, NCT00625209 .).
Spent batteries contain hazardous materials, including numerous metals (cadmium, lead, nickel, zinc, etc.) that are present at high concentrations. Therefore, proper treatment of these wastes is ...necessary to prevent their harmful effects on human health and the environment. Current recycling processes are mainly applied to treat each type of spent battery separately. In this laboratory study, a hydrometallurgical process has been developed to simultaneously and efficiently solubilize metals from spent batteries. Among the various chemical leaching agents tested, sulfuric acid was found to be the most efficient and cheapest reagent.
A Box-Behnken design was used to identify the influence of several parameters (acid concentration, solid/liquid ratio, retention time and number of leaching steps) on the removal of metals from spent batteries. According to the results, the solid/liquid ratio and acid concentration seemed to be the main parameters influencing the solubilization of zinc, manganese, nickel, cadmium and cobalt from spent batteries. According to the results, the highest metal leaching removals were obtained under the optimal leaching conditions (pulp density = 180 g/L (w/v), H2SO4 = 1 M, number of leaching step = 3 and leaching time = 30 min). Under such optimum conditions, the removal yields obtained were estimated to be 65% for Mn, 99.9% for Cd, 100% for Zn, 74% for Co and 68% for Ni. Further studies will be performed to improve the solubilization of Mn and to selectively recover the metals.
•Metals present in spent batteries were efficiently recycled.•Sulfuric acid was proved to be an efficient leaching agent to solubilize metals.•Optimum leaching conditions were determined using a Box-Behnken design.•Up to 65% of Mn, 68% of Ni, 74% of Co and 100% of Cd and Zn were solubilized.
The use of CO2 mineral carbonation represents an attractive approach to recycling waste concrete. In this study, the effect of gas pressure, Liquid/Solid (L/S) ratio (w/w), Gas/Liquid (G/L) ratio ...(v/v) and reaction time for CO2 sequestration were investigated. While carbonation of such matrix is already described, this study opens new insights in concrete carbonation. To increase the reactivity potential of concrete, the fine fraction (<500 μm), which contains mostly cement paste, was separated from the inert coarse aggregates. Separation was conducted by crushing and sieving. The ground fine concrete fraction showed enhanced reactivity with 75% of CO2 removed (corresponding to 0.057 g CO2 removed/sample) compared to that of raw concrete, with 54% of CO2 removed (corresponding to 0.034 g CO2 removed/sample). Tests were conducted under 144 psi of gas pressure (9.93 Bars) at ambient temperature for 10 min. On the other hand, the resulting aggregates fraction have an improved potential recycling value. The new proposed approach allows better carbonation efficiency and increases the overall valuation of waste concrete.
Limited numbers of operated patients with chronic thromboembolic pulmonary hypertension (CTEPH) are refractory to pulmonary endarterectomy (PEA) and experience persistent pulmonary hypertension (PH). ...We retrospectively assessed lung histology available from nine patients with persistent PH (ineffective PEA (inPEA) group) and from eight patients transplanted for distal CTEPH inaccessible by PEA (noPEA group). Microscopically observed peculiarities were compared with the histology of a recently developed CTEPH model in piglets. Pre-interventional clinical/haemodynamic data and medical history of patients from the inPEA and noPEA groups were collected and analysed. Conspicuous remodelling of small pulmonary arteries/arterioles, septal veins and pre-septal venules, including focal capillary haemangiomatosis, as well as pronounced hypertrophy and enlargement of bronchial systemic vessels, were the predominant pattern in histology from both groups. Most findings were reproduced in our porcine CTEPH model. Ink injection experiments unmasked abundant venular involvement in so-called small vessel or microvascular disease, as well as post-capillary bronchopulmonary shunting in human and experimental CTEPH. Microvascular disease is partly due to post-capillary remodelling in human and experimental CTEPH and appears to be related to bronchial-to-pulmonary venous shunting. Further studies are needed to clinically assess the functional importance of this finding.
Understanding the spatial distribution of organic and/or inorganic contaminants is crucial to facilitate decision-making of rehabilitation strategies in order to ensure the most appropriate ...management of contaminated sites in terms of contaminant removals efficiencies and operating costs. For these reasons, various interpolation methods Thiessen Polygon (TP) method, inverse of distance (IDW) method, ordinary kriging (OK), as well as sequential Gaussian simulations (SGS) were used to better understand the spatial distribution of As, Cr, Cu, pentachlorophenol (PCP) and dioxins and furans (PCDD/F) found onto a specific industrial site. These methods do not only vary in complexity and efficiency but also lead to different results when using values coming from the same characterization campaign. Therefore, it is often necessary to evaluate their relevance by performing a comparative analysis. The results showed that ordinary kriging (OK) was a better estimator of the mean and more advanced compared to the two other methods of interpolation (TP and IDW). However, it appeared that SGS has the same power than OK but it also permitted to calculate a reliable value of the probabilities of exceeding regulatory cut-offs of contamination.
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•Fate and behavior of PCP, PCDD/F, As, Cr and Cu on an treated wood storage site.•Mapping the spatial distribution of (in-)organic contaminants on an industrial site.•Comparison of interpolation and SGS method to assess volume of contaminated soils.•SGS was the most suitable method for risk assessment of contaminated soil.
Keeping a diary for patients while they are in the intensive care unit (ICU) might reduce their posttraumatic stress disorder (PTSD) symptoms.
To assess the effect of an ICU diary on the ...psychological consequences of an ICU hospitalization.
Assessor-blinded, multicenter, randomized clinical trial in 35 French ICUs from October 2015 to January 2017, with follow-up until July 2017. Among 2631 approached patients, 709 adult patients (with 1 family member each) who received mechanical ventilation within 48 hours after ICU admission for at least 2 days were eligible, 657 were randomized, and 339 were assessed 3 months after ICU discharge.
Patients in the intervention group (n = 355) had an ICU diary filled in by clinicians and family members. Patients in the control group (n = 354) had usual ICU care without an ICU diary.
The primary outcome was significant PTSD symptoms, defined as an Impact Event Scale-Revised (IES-R) score greater than 22 (range, 0-88; a higher score indicates more severe symptoms), measured in patients 3 months after ICU discharge. Secondary outcomes, also measured at 3 months and compared between groups, included significant PTSD symptoms in family members; significant anxiety and depression symptoms in patients and family members, based on a Hospital Anxiety and Depression Scale score greater than 8 for each subscale (range, 0-42; higher scores indicate more severe symptoms; minimal clinically important difference, 2.5); and patient memories of the ICU stay, reported with the ICU memory tool.
Among 657 patients who were randomized (median interquartile range age, 62 51-70 years; 126 women 37.2%), 339 (51.6%) completed the trial. At 3 months, significant PTSD symptoms were reported by 49 of 164 patients (29.9%) in the intervention group vs 60 of 175 (34.3%) in the control group (risk difference, -4% 95% CI, -15% to 6%; P = .39). The median (interquartile range) IES-R score was 12 (5-25) in the intervention group vs 13 (6-27) in the control group (difference, -1.47 95% CI, -1.93 to 4.87; P = .38). There were no significant differences in any of the 6 prespecified comparative secondary outcomes.
Among patients who received mechanical ventilation in the ICU, the use of an ICU diary filled in by clinicians and family members did not significantly reduce the number of patients who reported significant PTSD symptoms at 3 months. These findings do not support the use of ICU diaries for preventing PTSD symptoms.
ClinicalTrials.gov Identifier: NCT02519725.
Since 20 years, titanium oxide materials and in particular, lithium titanate spinel Li
4
Ti
5
O
12
(LTO) were considered as promising negative electrode materials for lithium-ion cells. In the case ...of the TiNb
2
O
7
compound (TNO), which has a larger theoretical lithiation capacity of 388 mAh g
−1
, few studies have focused on the outgassing of the material. In this work, we quantified the volume produced as a function of different cycling parameters and then characterized the produced species and show a prevalence of H
2
gas. The use of carbon coating as a mitigation strategy and its limitation is also discussed.
Graphical abstract
Mineral carbonation (MC) represents a promising alternative for sequestering CO2. In this work, the CO2 sequestration capacity of the available calcium-bearing materials waste concrete and ...anorthosite tailings is assessed in gas–solid–liquid and gas–solid routes using 18.2% flue CO2 gas. The objective is to screen for a better potential residue and phase route and as the ultimate purpose to develop a cost-effective process.
The results indicate the possibility of removing 66% from inlet CO2 using waste concrete for the aqueous route. However, the results that were obtained with the carbonation of anorthosite were less significant, with 34% as the maximal percentage of CO2 removal. The difference in terms of reactivity could be explained by the accessibility to calcium. In fact, anorthosite presents a framework structure wherein the calcium is trapped, which could slow the calcium dissolution into the aqueous phase compared to the concrete sample, where calcium can more easily leach.
In the other part of the study concerning gas–solid carbonation, the results of CO2 removal did not exceed 15%, which is not economically interesting for scaling up the process.
The results obtained with waste concrete samples in aqueous phase are interesting. In fact, 34.6% of the introduced CO2 is converted into carbonate after 15 min of contact with the gas without chemical additives and at a relatively low gas pressure.
Research on the optimization of the aqueous process using waste concrete should be performed to enhance the reaction rate and to develop a cost-effective process.
•Dry and aqueous flue gas mineral carbonation routes were investigated.•Two types of calcium-bearing residues were tested.•Dry phase experiments did not showed any carbonates formation.•Waste concrete is more reactive than anorthosite residues.•34.6% of CO2 was converted into carbonate with concrete samples in aqueous phase.
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