Comparison of mantle lithosphere beneath early Triassic kimberlite fields in Siberian craton reconstructed from deep-seated xenocrysts

Mantle xenocrysts from Early Triassic kimberlite pipes from Kharamai, Ary Mastakh and Kuranakh fields in the Anabar shield of Siberia revealing similar compositional trends were studied to estimate the superplume influence on the SCLM. PT reconstructions using monomineral thermobarometry for 5 phases show division of the SCLM beneath the Kharamai field into 6 units: pyroxenitic Fe-rich (1-2 GPa) and Mg-rich (2-3 GPa) layers; middle with two levels of Gar -Sp pyroxenites at ∼3 and 4 -5 GPa; Ga- dunite –harzburgites ∼ 4.5-6.5 GPa subjected to Ilm-Px vein metasomatism, and a Mg-rich dunite lower part. In the Anabar shield (Ary Mastakh, Dyuken and Kuranakh fields) mantle lithosphere is composed of three large units divided into two parts: upper part with amphiboles and phlogopite; two levels of pyroxenites and eclogites at 3 and 4 GPa, and a lower part composed of refertilized dunites. Diagrams showing P- Fe#Gar clusters for garnets and omphacites illustrate the differences between SCLM of these localities. Differences of Triassic SCLM from Devonian SCLM are in simple layering; abundance of Na-Cr-amphiboles and metasomatism in the upper SCLM part, thick pyroxenite - eclogite layer and lower part depletion, heated from SCLM base to 5.0 GPa. Kharamai mantle clinopyroxenes represent three geochemical types: 1) harzburgitic with inclined linear REE, HFSE troughs and elevated Th, U; 2) lherzolitic or pyroxenitic with round TRE patterns and decreasing incompatible elements; 3) eclogitic with Eu troughs, Pb peak and high LILE content. Calculated parental melts for garnets with humped REE patterns suggest dissolution of former Cpx and depression means Cpx and garnets extraction. Clinopyroxenes from Ary Mastakh fields show less inclined REE patterns with HMREE troughs and an increase of incompatible elements. Clinopyroxenes from Kuranakh field show flatter spoon-like REE patterns and peaks in Ba, U, Pb and Sr, similar to those in ophiolitic harzburgites. The PT diagrams for the mantle sections show high temperature gradients in the uppermost SCLM accompanied by an increase of P-Fe#Ol upward and slightly reduced thickness of the mantle keel of the Siberian craton, resulting from the influence of the Permian -Triassic superplume, but with no signs of delamination

Critically Ill Patients with Visceral Nocardia Infection, France and Belgium, 2004-2023.

peer reviewedWe studied 50 patients with invasive nocardiosis treated during 2004-2023 in intensive care centers in France and Belgium. Most (65%) died in the intensive care unit or in the year after admission. Nocardia infections should be included in the differential diagnoses for patients in the intensive care setting

Defining successful non‐invasive ventilation initiation: Data from a real‐life cohort

International audienceBackground and objective: When home non-invasive ventilation (NIV) is initiated, five goals need to be achieved: a daily use >4 h/day, an improvement in gas exchange, health-related quality of life (HRQL) and sleep quality without side effects. Our aim was to assess how frequently these five goals were reached and the factors predictive of achievement.Methods: We conducted a monocentric cohort study that included patients electively established on home NIV over 2 years. HRQL was assessed at baseline and follow-up by the Severe Respiratory Insufficiency questionnaire. Adequate initiation was defined as the achievement of at least three of five goals and successful initiation as the achievement of all.Results: Two-hundred and fifty patients were included at baseline. NIV was initiated for: obesity hypoventilation syndrome (n = 95; 38%), neuromuscular disease (n = 70; 28%), chronic obstructive pulmonary disease (n = 66; 26%) and chest wall disease (n = 19; 8%). At follow-up, measures of all five goals were available in 141 (56%) patients. NIV initiation was adequate for 96 (68%) patients and successful for 12 (9%) patients. In multivariate analysis, a tidal volume ≥ 7.8 ml/kg of ideal body weight was associated with an increased likelihood of adequate NIV initiation (hazard ratio: 5.765 [95% CI:1.824–18.223], p = 0.006]. Improvement in daytime partial arterial carbon dioxide pressure (PaCO2) was not correlated to improvement in HRQL or sleep quality. Severe to very severe NIV-related side effects occurred in 114 (47%) patients and were associated with higher daytime PaCO2 (6.35 ± 1.08 vs. 5.92 ± 0.79 kPa, p < 0.001).Conclusion: Successful home NIV initiation is rarely achieved in real life. HRQL and NIV tolerance should be assessed to improve patient-centred outcomes

Capacitively coupled plasma used to simulate Titan's atmospheric chemistry

International audienceA complex chemistry in Titan's atmosphere leads to the formation of organic solid aerosols. We use a radio-frequency (RF) capacitively coupled plasma discharge produced in different N2–CH4 mixtures (from 0% to 10% of CH4) to simulate this chemistry. The work presented here was devoted to the study of the plasma discharge. In our experiment, the electron density is measured by the resonant cavity method and is about 1015 m−3 in pure N2 plasma at 30 W excitation RF power. It decreases by a factor of 2 as soon as CH4 is present in the discharge, even for a proportion as small as 2% of CH4. An optical emission spectroscopy diagnostic is installed on the experiment to study the evolution of the N2 bands and to perform actinometry measurements using Ar lines. This diagnostic allowed us to measure variations in the electron temperature and to show that a decrease in the density of the electrons can be compensated by an increase in their energy. We have also used an experimental setup where the plasma is tuned in a pulsed mode, in order to study the formation of dust particles. We observed variations in the self-bias voltage, the RF injected power and the intensities of the nitrogen bands, which indicated that dust particles were formed. The characteristic dust formation time varied, depending on the experimental conditions, from 4 to 110 s. It was faster for higher pressures and for smaller proportions of CH4 in the gas mixture

Evaluation of non-nutritional calories in intensive care patients with acute respiratory distress syndrome due to coronavirus disease-19: a retrospective observational study

Summary: Background &amp; Aims: Nutrition therapy is a critical component of care for critically ill patients in the intensive care unit (ICU). Caloric intake can be provided by artificial nutrition and also by some treatments providing non-nutritional calories (NNCs). The aim of this study was to assess the contribution of NNCs from propofol and dextrose infusions to daily caloric intake. Methods: A retrospective observational study was carried out in three ICUs of a university hospital. Mechanically ventilated patients admitted to ICU for acute respiratory distress syndrome (ARDS) due to coronavirus disease 2019 (COVID-19) were included. Daily caloric intake, including NNCs from propofol and dextrose infusions, and calories from artificial nutrition was assessed over the initial seven days of ICU admission. Results: A total of 157 patients were included in the analysis. During the early phase of ICU admission, NNCs constituted all the proportion of caloric intake (Day 1: 100% [100–100], Day 2: 100% [100–100], Day 3: 100% [63–100]). This dominance gradually decreased with the introduction of artificial nutrition after a median of 4 days [3–5]. Propofol contributed significantly to NNCs, constituting a median of 26.6% [15.5–54.0] of total daily caloric intake and 66.2% [53.0–76.4] of daily NNCs intake in patients receiving propofol. By Day 7, only 47.3% of patients had reached their caloric target, while 45.8% remained below target and 6.9% were above target. The instances of overnutrition were minimal and were often associated with NNCs, particularly propofol. Mortality at Day 28 in patients who received propofol during the first 7 days was 32/117 (27%) versus 23/40 (57%) in those who did not (P < 0.001). Conclusions: Our study emphasizes the significant role of NNCs in the early nutritional intake of ICU patients suffering from ARDS due to COVID-19. These findings highlight the need for careful nutritional management in these patients, with particular consideration given to NNCs. Future research should investigate strategies to optimize nutritional support in this specific population