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Metasomatism refers to the process during which a pre-existing rock undergoes compositional and mineralogical transformations associated with chemical reactions triggered by the reaction of fluids which invade the protolith. It changes chemical compositions of minerals, promotes their dissolution and precipitation of new minerals. In this paper, we review metasomatic alteration of type 3 ordinary (H, L, LL) and carbonaceous (CV, CO, CK) chondrites, including (i) secondary mineralization, (ii) physicochemical conditions, (iii) chronology (53Mn-53Cr, 26Al-26Mg, 129I-129Xe) of metasomatic alteration, (iv) records of metasomatic alteration in H, O, N, C, S, and Cl isotopic systematics, (v) effects of metasomatic alteration on O- and Al-Mg-isotope systematics of primary minerals in chondrules and refractory inclusions, and (vi) sources of water ices in metasomatically altered CV, CO, and ordinary chondrites, and outline future studies. [ABSTRACT FROM AUTHOR]

Obesity is a complex, multifactorial, chronic disease that acts as a gateway to a range of other diseases. Evidence from recent studies suggests that changes in oxygen availability in the microenvironment of metabolic organs may exert an important role in the development of obesity-related cardiometabolic complications. In this review, we will first discuss results from observational and controlled laboratory studies that examined the relationship between reduced oxygen availability and obesity-related metabolic derangements. Next, the effects of alterations in oxygen partial pressure (pO2) in the adipose tissue, skeletal muscle and the liver microenvironment on physiological processes in these key metabolic organs will be addressed, and how this might relate to cardiometabolic complications. Since many obesity-related chronic diseases, including type 2 diabetes mellitus, cardiovascular diseases, chronic kidney disease, chronic obstructive pulmonary disease and obstructive sleep apnea, are characterized by changes in pO2 in the tissue microenvironment, a better understanding of the metabolic impact of altered tissue oxygenation can provide valuable insights into the complex interplay between environmental and biological factors involved in the pathophysiology of metabolic impairments. This may ultimately contribute to the development of novel strategies to prevent and treat obesity-related cardiometabolic diseases. [ABSTRACT FROM AUTHOR]

Human populations are experiencing unprecedented growth and longevity with lingering knowledge gaps of the characteristics, mechanisms, and pathologies of senescence. Invasive measurements and long-term control conditions for longitudinal studies are infeasible, necessitating the need for surrogate animal models. Rats have short lifespans (2–3 years) with translatable cardiovascular systems, and Sprague Dawley microcirculatory preparations are key to studying the oxygen transport mechanisms critical to the loss of skeletal muscle function in aging. Here we present baseline physiological data of 61 male, Sprague Dawley rats at 3, 6, 12, 18, and 24 months of age. Anesthetized animals were surgically prepared for femoral arterial and venous cannulations, tracheal intubation, and exteriorization of the spinotrapezius muscle. Measurements included cardiovascular function, blood gases, and peripheral tissue interstitial oxygen tension (PISFO2) using phosphorescence quenching microscopy. Intrinsic heart rates decreased with age without significant changes to blood pressure. Arterial oxygen tension declined 17% by 18 and 24 Months (p < 0.05) while pACO2 and PISFO2 were unchanged. Lactate was elevated at 12 and 18 Months along with an alkaline shift in blood pH. Heart rate and decreased pAO2 decoupled from pACO2 are conserved phenomena in human aging. The continuity of resting PISFO2 despite an anaerobic shift in metabolism may be due to declining mitochondrial function and dysregulation of the vascular response to hypoxemia, which are also present in aged humans. These physiological and microcirculatory data offer a useful experimental model for investigating the detailed changes in oxygen supply and demand that affect senescing skeletal muscles in rats and humans. [ABSTRACT FROM AUTHOR]

Although alveolar hyperoxia exacerbates lung injury, clinical studies have failed to demonstrate the beneficial effects of lowering the fraction of inspired oxygen (FIO2) in patients with acute respiratory distress syndrome (ARDS). Atelectasis, which is commonly observed in ARDS, not only leads to hypoxemia but also contributes to lung injury through hypoxia-induced alveolar tissue inflammation. Therefore, it is possible that excessively low FIO2 may enhance hypoxia-induced inflammation in atelectasis, and raising FIO2 to an appropriate level may be a reasonable strategy for its mitigation. In this study, we investigated the effects of different FIO2 levels on alveolar tissue hypoxia and injury in a mechanically ventilated rat model of experimental ARDS with atelectasis. Rats were intratracheally injected with lipopolysaccharide (LPS) to establish an ARDS model. They were allocated to the low, moderate, and high FIO2 groups with FIO2 of 30, 60, and 100%, respectively, a day after LPS injection. All groups were mechanically ventilated with an 8 mL/kg tidal volume and zero end-expiratory pressure to induce dorsal atelectatic regions. Arterial blood gas analysis was performed every 2 h. After six hours of mechanical ventilation, the rats were euthanized, and blood, bronchoalveolar lavage fluid, and lung tissues were collected and analyzed. Another set of animals was used for pimonidazole staining of the lung tissues to detect the hypoxic region. Lung mechanics, ratios of partial pressure of arterial oxygen (PaO2) to FIO2, and partial pressure of arterial carbon dioxide were not significantly different among the three groups, although PaO2 changed with FIO2. The dorsal lung tissues were positively stained with pimonidazole regardless of FIO2, and the HIF-1α concentrations were not significantly different among the three groups, indicating that raising FIO2 could not rescue alveolar tissue hypoxia. Moreover, changes in FIO2 did not significantly affect lung injury or inflammation. In contrast, hypoxemia observed in the low FIO2 group caused injury to organs other than the lungs. Raising FIO2 levels did not attenuate tissue hypoxia, inflammation, or injury in the atelectatic lung region in experimental ARDS. Our results indicate that raising FIO2 levels to attenuate atelectasis-induced lung injury cannot be rationalized. [ABSTRACT FROM AUTHOR]

Background: Continuous veno-venous hemodiafiltration (CVVHDF) is used in critically ill patients, but its impact on O₂ and CO₂ removal, as well as the accuracy of resting energy expenditure (REE) measurement using indirect calorimetry (IC) remains unclear. This study aims to evaluate the effects of CVVHDF on O₂ and CO₂ removal and the accuracy of REE measurement using IC in patients undergoing continuous renal replacement therapy. Design: Prospective, observational, single-center study. Methodology: Patients with sepsis undergoing CVVHDF had CO₂ flow (QCO₂) and O₂ flow (QO₂) measured at multiple sampling points before and after the filter. REE was calculated using the Weir equation based on V̇CO₂ and V̇O₂ measured by IC, using true V̇CO₂ accounting for the CRRT balance, and estimated using the Harris-Benedict equation. The respiratory quotient (RQ), the ratio of V̇CO₂ to V̇O₂, was evaluated by comparing measured and true values. Results: The mean QCO₂ levels measured upstream of the filter were 76.26 ± 17.33 ml/min and significantly decreased to 62.12 ± 13.64 ml/min downstream of the filter (p < 0.0001). The mean QO₂ levels remained relatively unchanged. The mean true REE was 1774.28 ± 438.20 kcal/day, significantly different from both the measured REE of 1758.59 ± 434.06 kcal/day (p = 0.0029) and the estimated REE of 1619.36 ± 295.46 kcal/day (p = 0.0475). The mean measured RQ value was 0.693 ± 0.118, while the mean true RQ value was 0.731 ± 0.121, with a significant difference (p < 0.0001). Conclusions: CVVHDF may significantly alter QCO₂ levels without affecting QO₂, influencing the REE and RQ results measured by IC. However, the impact on REE is not clinically significant, and the REE value obtained via IC is closer to the true REE than that estimated using the Harris-Benedict equation. Further studies are recommended to confirm these findings. [ABSTRACT FROM AUTHOR]

Agroforestry is an alternative land use practice that holds promise for societal benefits and the attainment of ecosystem sustainability. The objectives of this study were to evaluate the tree diversity, carbon sequestration, soil carbon pool, oxygen production and rice productivity under traditional agroforestry systems at different elevations in the Garhwal Himalayan region of India. Tree diversity, carbon sequestration and oxygen production were quantified by field measurements (using 0.04 ha quadrats) and subsequent calculations. Rice productivity was assessed using grain yield, straw yield and biological yield, while soil properties were analyzed in the laboratory using standard methods. Results of the study showed that tree diversity was higher at the 1200–1600 m elevation and had a maximum Shannon Diversity Index (1.29) and Simpson Diversity Index (0.69). The 1600–2000 m elevation stored more carbon (34.43 Mg ha−1) and total oxygen production (91.79 Mg ha−1). Among the agroforestry trees, Quercus leucotrichophora, Melia azedarach and Prunus cerasoides showed the highest carbon storage and total oxygen production. Elevation and soil depth were found to affect the soil properties. The agroforestry systems had higher soil organic carbon and lower bulk density than sole cropping systems. Compared to the agroforestry system, the monoculture produced more rice (Oryza sativa). The study shows that traditional agroforestry is a valuable tool for carbon sequestration and soil improvement, albeit with potential compromises in crop productivity. It emphasises the need for tailored management approaches to harness the ecological and environmental benefits of agroforestry in the Himalayas. This study draws attention to the potential of traditional agroforestry in the Garhwal Himalaya for carbon sequestration, climate change mitigation and soil quality improvement which provides a reference for striking a balance between the ecological advantages of agroforestry and the socio-economic considerations of local communities. However, it also underlines the importance of considering trade-offs between environmental benefits and crop yields when implementing such agroforestry systems. Highlights: • Elevation plays an important role for tree diversity, net carbon sequestration and net oxygen production in Himalaya. • Compared to sole cropping system, agroforestry systems had higher soil pH and soil organic carbon, along with lower bulk density. • Production was high in sole cropping system while agroforestry had ecological benefits like carbon storage and soil improvement. [ABSTRACT FROM AUTHOR]

Emission of prompt gamma rays in lanthanum and praseodymium nuclei triggered by (n,n'γ) inelastic scattering reactions of fission neutrons was investigated with the instrument FaNGaS (Fast Neutron-induced Gamma-ray Spectrometry) at Heinz Maier-Leibnitz Zentrum (MLZ). We identified 125 gamma lines (54 for lanthanum and 71 for praseodymium), for which we give the relative intensities and production cross sections. Presence of oxygen and chlorine in the samples was exploited to verify previous measurements. Our results are consistent with available literature data but also enhance it as we detect new lines and recognize a few false assignments. In addition, for a counting time of 12 h we estimated the detection limits of lanthanum and praseodymium as 0.6 and 0.4 mg, respectively. [ABSTRACT FROM AUTHOR]

To improve the photoelectric properties of Ag-based transparent conductive films, TCO/Ag/TCO multilayer films were prepared on K9 glass substrates with the magnetron sputtering. The dielectric TCO (transparent conductive oxide) layer was AZO (Al-doped ZnO, sputtered with or without oxygen) or ITO (Sn-doped In2O3, sputtered with oxygen). The effects of the combination of dielectric layers, and the AZO layer sputtering with or without oxygen were investigated. The results indicated that the crystallization quality of the Ag layer deteriorated and its roughness increased when the AZO layer was sputtered with oxygen, and the photoelectric properties of the multilayer film also notably decreased. Additionally, the film exhibited better photoelectric properties when the type of TCO on the top was different from that on the bottom. Among them, the crystallization quality of Ag layer was the best when the multilayer film was structured as ITO/Ag/AZO (sputtered without oxygen). This film exhibited a visible average transmittance of 82.36%, a sheet resistance of 9.11 Ω/sq, and a Figure-of-Merit (FOM) as high as 15.75 mΩ−1. [ABSTRACT FROM AUTHOR]

Chemical heating rates were derived from three of the most significant reactions based on the analysis of common volume rocket-borne measurements of temperature, atomic oxygen densities, and neutral air densities. This is one of the first instances of the retrieval of nighttime chemical heat through the utilization of non-emissive observations of atomic oxygen concentrations, obtained through in situ measurements, performed at the Andøya Space Center (69°N, 16°E) at 01:44:00 UTC on 5 March 2015. Furthermore, we determine the heating efficiency for one of the most significant reactions of atomic hydrogen with ozone and illustrate the methodology for such calculations based on known atomic oxygen and temperature. Subsequently, using ozone values obtained from satellite observations, we retrieved odd-hydrogens and total chemical heat. Finally, we compared the retrieved chemical heat with the heat from turbulent energy dissipation. Our findings reveal that the vertically averaged chemical heat is greater than the heat from turbulent energy dissipation throughout the entire mesopause region during nocturnal conditions. The heating rates of turbulent energy dissipation may exceed the chemical heating rates only in narrow peaks, several hundred meters wide. [ABSTRACT FROM AUTHOR]

This study optimizes VT and ΔVT in amorphous indium-gallium-zinc-oxide (a-IGZO) field-effect transistors (FETs) by examining the influence of both channel length (L) and Ga composition. It was observed that as the ratio of In: Ga: Zn changed from 1:1:1 to 0.307:0.39:0.303 in the IGZO film, both VT and ΔVT decreased by 0.1 V at the shortest channel length (L = 0.5 μm). This reduction was attributed to the change in the oxygen concentration in IGZO due to the variation in Ga composition. In addition, as the channel length decreased from 10 μm to 0.5 μm, VT decreased by up to 0.7 V, and ΔVT decreased by up to 0.4 V. This observation was due to diffusion of oxygen vacancies (VO) from the source and drain into the main channel. To provide a comprehensive understanding, we quantitatively modeled the doping concentration of IGZO and the trap density of gate insulator (GI) traps using TCAD simulation based on Ga composition and diffusion of VO. Using this approach, we propose a method to optimize the design of a-IGZO FETs with high VT and low ΔVT in short-channel devices by adjusting the Ga composition. [ABSTRACT FROM AUTHOR]

In this paper, we prove a global large solution result to the Keller–Segel–Navier–Stokes equations in critical Besov spaces. The result indicates that the global solutions exist without any small conditions imposed on the initial oxygen concentration c 0 . This is different from some known large solutions results, which allow the part large initial data u 0 . [ABSTRACT FROM AUTHOR]

This study develops and validates three photochemical inversion models to retrieve atomic oxygen ion density ([O+]) profiles from 630.0 nm airglow emissions in the mid-latitude ionosphere during geomagnetically quiet period. Using passive ground-based instruments and empirical models, the models were tested and compared against electron density data from FORMOSAT-3/COSMIC (F3/C) and DPS-4 digisonde at Irkutsk. Among the models, Inversion Model 3 showed the strongest agreement with observations, particularly in capturing seasonal variations such as the June–July peak and a secondary March–April peak, which were absent in IRI-2012 predictions. These results highlight the potential of Inversion Model 3 for accurate [O+] retrieval, offering a novel approach for monitoring ionospheric variability using passive photometric observations. [ABSTRACT FROM AUTHOR]

Archival data on the concentration of dissolved oxygen and the temperature of the upper layer of the Black Sea over the past 100 years are analyzed. It is found that in both the northwestern and open parts of the sea in the period from 1923 to 1932, the lowest concentrations of dissolved oxygen in the past 100 years were observed. They were equal to about 260 M, which was significantly (by 14–33%) lower than the concentration of oxygen in the upper layer of different parts of the Black Sea observed during the period of its decline 50 years later. It is shown that the decrease in oxygen levels in the 1920s–early 1930s was primarily due to the anomalous heating of the surface water layer during this period. This is its fundamental distinction from the decline in dissolved oxygen that falls on the last quarter of the 20th century and the beginning of the 21st century. The main reason for occurrence of the secondary minimum of oxygen was eutrophication of water, which started in the northwestern part of the sea and then spread to the inner parts of the water area. [ABSTRACT FROM AUTHOR]

In the present research work, structural, electronic, and optical properties of oxygen functionalized 2D ScBiS3 monolayer have been carried out by using the first principles calculations. Both SBiS3O (single side functionalization) and ScBiS3O2 (double side functionalization) monolayer have stable hexagonal structure. The ScBiS3 monolayer has indirect bandgap of 1.95 eV. The oxygen functionalization on the ScBiS3 monolayer reduce the electronic bandgap remarkably. The ScBiS3O and ScBiS3O2 monolayers possess electronic bandgap of 1.075 eV and 0.32 eV respectively. The monolayer ScBiS3 with and without oxygen functionalization shows optical absorption in the visible and ultraviolet region, which suggest its potential application in nanoscale optoelectronic devices. [ABSTRACT FROM AUTHOR]

The majority of reaction conditions employed in SF6 conversion research are characterized by elevated temperatures and pressures, resulting in a considerable expenditure of energy. The transformation of SF6 under mild conditions represents a viable methodology at this time. It has been demonstrated that the conditions required for the photoconversion of SF6 are relatively mild. Furthermore, the defect engineering of catalysts has been shown to be an effective strategy for enhancing the photocatalytic performance of photocatalysis. Thus, we utilized two-dimensional materials as a model for our research. These materials have active sites that are highly dense and uniform, allowing us to thoroughly examine how defects affect the SF6 photoconversion process. By synthesizing ZnO atomic layers with oxygen vacancies and confirming their presence using various techniques, we found that these vacancies enhanced light absorption and promoted the separation of charge carriers. These results suggest that the oxygen-deficient ZnO atomic layers have superior SF6 photoconversion performance compared to the pristine ZnO atomic layers. Overall, the findings of this study indicate that the incorporation of defects in photocatalysts is a crucial strategy for optimizing pivotal photocatalytic processes and enhancing the efficacy of SF6 photoconversion. We initially built clear models of two-dimensional atomic layers with defect concentrations, and hence directly disclose the defect type and distribution at atomic level. As a prototype, defective ZnO nanosheets with atomic thickness are successfully synthesized. Also, we use defective ZnO atomic layers to achieve light conversion of SF6 under mild conditions, which provides a new path to solve the environmental pollution of perfluorinated compounds. [ABSTRACT FROM AUTHOR]

The control of oxygen is paramount in achieving high-performance titanium (Ti) parts by powder metallurgy such as metal injection molding (MIM). In this study, we purposely selected the Ti and Ti–6Al–4V powders as the reference materials since these two are the most representative Ti materials in the industry. Herein, hydride–dehydride (HDH) Ti powders were pre-oxidized to examine the effect of oxygen variation on the characteristics of oxide layer on the particle surface and its resultant color feature. The results indicate that the thickness and Ti oxide level (Ti0 → Ti4+) of the oxide layer on the HDH Ti powders increased as the oxygen content increased, leading to the transition of color appearance from grey, brown to blue. This work aids in the powder feedstock selection at the initial stage in powder metallurgy. In addition, the development of oxygen content was comprehensively studied during the MIM process using the gas-atomized (GA) Ti–6Al–4V powders. Particularly, the oxygen variation in the form of oxide layer, the change of oxygen content in the powders, and the relevant parts were investigated during the processes of kneading, injection, debinding, and sintering. The oxygen variation was mainly concentrated in the sintering stage, and the content increased with the increase of sintering temperature. The variation of oxygen content during the MIM process demonstrates the crucial role of powder feedstock and sintering stage in controlling oxygen content. This work provides a piece of valuable information on oxygen detecting, control, and manipulation for the powder and processing in the industry of Ti and its alloys by powder metallurgy. [ABSTRACT FROM AUTHOR]

The structural transformations occurring in a chlorine monolayer on a previously oxidized Ag(111) surface, containing Ag6O6 oxide rings centered at vacancies in the upper silver layer, were investigated using scanning tunneling microscopy (STM) and density functional theory (DFT) calculations. It is found that, at a temperature of 80 K in the initial stage, chlorine atoms form chain structures in the gaps between oxide rings. As the coverage increases, chlorine forms domains having a uniaxially compressed structure, with boundaries determined by the local oxide. Continued Cl2 adsorption leads to condensation of molecular chlorine. Annealing of the resulting system to 300 K causes significant structural transformations on the surface, resulting in the formation of islands of (20–30) Å in size with the reconstruction Ag(111)-(3 × 3)-Cl, as well as chains of objects with a height of ≈1 Å. Based on the DFT calculations these objects were found to be O–Cl quasi-molecules, formed by surface oxygen atoms and adsorbed chlorine atoms. [ABSTRACT FROM AUTHOR]

This field study examined how sediment macroinfauna change patterns of sediment oxygen demand (SOD) throughout a diel oxygen cycle. Sediments with a greater faunal presence would be expected to have greater overall SOD, and at night may alter their behavior and influence SOD depending on their response to low-oxygen stress. Dynamic faunal bioturbation or bioirrigation behavior would also result in corresponding variation in SOD values on short time scales. In situ flow-through benthic metabolism chambers were used to measure SOD at a high temporal resolution in discrete sediment patches. Sediments with more macroinfauna had greater average SOD over the diel cycle, consistent with previous studies. Where more macroinfauna were present, they drove greater SOD during nightly low oxygen, presumably by enhancing their burrowing and irrigation activities. SOD was also more variable on a sub-diel timescale in sediments with more macroinfauna. Sediment oxygen demand is dynamic and highly sensitive both temporally, on very short timescales, and spatially, in terms of resident fauna, and their interaction produces heretofore unaccounted complexity in patterns of SOD particularly in shallow coastal systems. Extrapolations of temporally and spatially limited SOD measurements to a system-wide scale that do not account for the short-term and spatially variable effects of fauna may produce imprecise and misleading estimates of this critical ecosystem function. [ABSTRACT FROM AUTHOR]

We investigated trends in temperature, stratification, and hypolimnetic oxygen concentration of German lakes under climate change using observational data and hydrodynamic modelling. Observations from 46 lakes revealed that annually averaged surface temperatures increased by + 0.5 °C between 1990 and 2020 while bottom temperatures remained almost constant. Modelling of 12 lakes predicted further increases in surface temperatures by 0.3 °C/decade until the year 2099 in the most pessimistic emission scenario RCP 8.5 (RCP 4.5: + 0.18 °C/decade; RCP 2.6: + 0.04 °C/decade). Again, bottom temperatures increased much less while summer stratification extended by up to 38 days. Using a simplified oxygen model, we showed that hypolimnetic oxygen concentrations decreased by 0.7–1.9 mg L−1 in response to the extended stratification period. However, model runs assuming lower productivity (e. g. through nutrient reduction) resulted in increased oxygen concentrations even in the most pessimistic emission scenario. Our results suggest that the negative effects of climate change on the oxygen budget of lakes can be efficiently mitigated by nutrient control. [ABSTRACT FROM AUTHOR]

The American horseshoe crab, Limulus polyphemus, spawns in the intertidal zone and is thought to prefer conditions associated with the oxygen-rich sediments of the upper intertidal zone. However, they also spawn in the oxygen-poor sediments of the mid-intertidal zone. Such alternative habitats have traditionally been considered suboptimal, yet the consequences of spawning there are unknown. Here, eggs originating from upper- and mid-intertidal habitats were incubated under different abiotic conditions, and development rate and hatching success were measured. Eggs were collected in May 2021 from Long Island (Zach’s Bay), New York and incubated at two temperatures (26 °C and 20 °C), each coinciding with two O2 conditions (21% and 9.5% ambient). All eggs developed more slowly at the lower temperature and O2 levels, with eggs from the upper intertidal showing a greater decrease in rate than those from the mid-intertidal. Eggs from the upper intertidal had a higher hatching success overall which decreased with a lowering of either temperature or O2. The hatching success of eggs from the mid-intertidal only decreased when both variables were lower. Thus, eggs from upper intertidal habitats better use conditions traditionally considered optimal, while eggs from mid-intertidal habitats are hardier in conditions usually considered suboptimal. This could be due to differences in the adults that use each habitat or the developmental trajectory embryos take when exposed to particular habitat conditions. Either way, this novel finding suggests a strategy horseshoe crabs use to take advantage of environmental variation and underlies an adaptive response to alternative habitats once considered suboptimal. [ABSTRACT FROM AUTHOR]

Radiative cooling by molecules is a crucial process for hydrodynamic escape, as it can efficiently remove the thermal energy driving the outflow, acquired through X-ray and extreme UV absorption. Carbon oxides, such as CO and CO2, and their photochemical products are anticipated to serve as vital radiative cooling sources not only in atmospheres dominated by carbon oxides but also in H2-rich atmospheres. However, their specific effects on the hydrodynamic escape, especially in H2-rich atmospheres, have been inadequately investigated. In this study, we conduct 1-D hydrodynamic escape simulations for H2-rich atmospheres incorporating CO, CO2, and their chemical products on an Earth-mass planet. We consider detailed radiative cooling processes and chemical networks related to carbon oxides to elucidate their impacts on the hydrodynamic escape. In the escape outflow, CO2 undergoes rapid photolysis, producing CO and atomic oxygen, while CO exhibits photochemical stability compared to CO2. The H2 oxidation by atomic oxygen results in the production of OH and H2O. Consequently, the hydrodynamic escape is significantly suppressed by the radiative cooling effects of CO, H2O, OH, and H3+ even when the basal mixing fraction of CO and CO2 is lower than ~ 0.01. These mechanisms extend the lifetime of H2-rich atmospheres by about one order of magnitude compared to the case of pure hydrogen atmospheres on early Earth, which also results in negligible escape of heavier carbon- and nitrogen-bearing molecules and noble gases. [ABSTRACT FROM AUTHOR]

Purpose: The prevalence of infertility in Canada has substantially increased over 30 years, and plateaued success rates of culture systems warrant further optimization for transfer outcomes. In clinical programs, embryos commonly undergo extended culture under 5% O2 until the blastocyst stage. The aim of this study is to characterize the developmental competence and stress-related responses of embryos cultured under 5 versus 2% O2 in comparison to in vivo-derived blastocysts. We hypothesized 2% O2 compromises developmental competence through altered embryonic stress responses and induction of apoptosis-related genes relative to those cultured under 5% O2 and in vivo-derived blastocysts. Methods: Quantitative measures of development and relative expressions of a cohort of stress-related genes in CD1 mouse zygotes cultured to blastocysts under 5 or 2% O2 were compared to in vivo-derived embryos. Apoptotic responses were evaluated using an immunofluorescence assay for Caspase-3. Results: The mean percentage of blastocysts developed, and total cell number of embryos derived in vivo or cultured under 5% O2 was significantly higher than those cultured under 2% O2. Blastocyst expansion was greatest in embryos cultured under 5% O2. Stress response genes were significantly upregulated in embryos cultured under 2% O2, and expression of antioxidant-related genes was significantly lower in cultured versus in vivo-derived embryos. Caspase-3 immunofluorescence was significantly higher in cultured embryos versus in vivo-derived embryos. Conclusion: We inferred that 5% O2 systems better approximate physiologic oxygen availability for culture of mouse embryos, warranting re-evaluation of culturing embryos under threshold or sub-physiologic oxygen concentrations during clinical IVF programs. [ABSTRACT FROM AUTHOR]

This work focused on the physico-chemical, biochemical and microbiological characterization of a new organic fertilizer based on fermented forest litter (FFL) mixed with agro-industrial by-products, on the culture realized in airtight glass bottle. Under strict anaerobiosis (0% initial oxygen concentration (IOC)), after a 16-day batch culture, the bottle-headspace analysis showed that the specific CO2 production rate was low (0.014 mL/h.g dry matter) compared to those reached under aerobic conditions (e.g. 0.464 mL/h.g dm at 21% IOC). Moreover, the culture displayed a slight fermented fruity odour, mainly due to ethanol and ethyl acetate detected in the headspace (335 µL and 58.6 µL accumulated, respectively). The FFL organic matter degradation followed by infrared spectroscopy and catabolic potential and diversity characterized by BIOLOG® EcoPlates were poor and pH dropped to 4.54. The microbiome's metabolism was oriented toward lactic fermentation with medium acidification, enrichment in lactic acid bacteria (LAB), depletion in fungi and absence of pathogens. By increasing IOC from 0 to 21%, the respirometric activity, and the catabolic potential and diversity increased. However, some enterobacteria were detected above 5% IOC. Ethanol and ethyl acetate decreased strongly with IOC, and aromatics and proteins contained in the solid matrix remained in the culture. This study showed the importance of oxygen on the final product. A 2% IOC was found to ensure an optimal balance between LAB development, preservation of functional catabolic diversity and bio-product free of microbial pathogens. [ABSTRACT FROM AUTHOR]

Quadripartition neutrosophic number is an extension of the neutrosophic set constructed for modeling situations specifically with incomplete, indeterminate, and inconsistent information. In this paper, Quadripartition Neutrosophic Weighted Hamacher Averaging Aggregative operator and Quadripartition Neutrosophic Weighted Hamacher Geometric Aggregative operator are introduced. Hamacher aggregation operators are the extension of the algebraic aggregation operators and Einstein aggregation operators, which are more general and flexible. Some essential properties such as idempotency, commutativity, monotonicity, and boundedness properties have been investigated. A new MADM strategy is developed using the proposed operators. The entropy function is used to calculate the weights of the attributes in aggregating the decision maker's preferences. An MADM problem of COVID-19 patient's oxygen supply is solved to demonstrate the process. In addition, a comparison is made to ensure that the proposed strategies are consistent and superior. [ABSTRACT FROM AUTHOR]

Background: This narrative review was written by an expert panel to the members of the jury to help in the development of clinical practice guidelines on oxygen therapy. Results: According to the expert panel, acute hypoxemic respiratory failure was defined as PaO2 < 60 mm Hg or SpO2 < 90% on room air, or PaO2/FiO2 ≤ 300 mm Hg. Supplemental oxygen should be administered according to the monitoring of SpO2, with the aim at maintaining SpO2 above 92% and below 98%. Noninvasive respiratory supports are generally reserved for the most hypoxemic patients with the aim of relieving dyspnea. High-flow nasal cannula oxygen (HFNC) seems superior to conventional oxygen therapy (COT) as a means of avoiding intubation and may therefore be should probably be used as a first-line noninvasive respiratory support in patients requiring more than 6 L/min of oxygen or PaO2/FiO2 ≤ 200 mm Hg and a respiratory rate above 25 breaths/minute or clinical signs of respiratory distress, but with no benefits on mortality. Continuous positive airway pressure (CPAP) cannot currently be recommended as a first-line noninvasive respiratory support, since its beneficial effects on intubation remain uncertain. Despite older studies favoring noninvasive ventilation (NIV) over COT, recent clinical trials fail to show beneficial effects with NIV compared to HFNC. Therefore, there is no evidence to support the use of NIV or CPAP as first-line treatment if HFNC is available. Clinical trials do not support the hypothesis that noninvasive respiratory supports may lead to late intubation. The potential benefits of awake prone positioning on the risk of intubation in patients with COVID-19 cannot be extrapolated to patients with another etiology. Conclusions: Whereas oxygen supplementation should be initiated for patients with acute hypoxemic respiratory failure defined as PaO2 below 60 mm Hg or SpO2 < 90% on room air, HFNC should be the first-line noninvasive respiratory support in patients with PaO2/FiO2 ≤ 200 mm Hg with increased respiratory rate. Further studies are needed to assess the potential benefits of CPAP, NIV through a helmet and awake prone position in patients with acute hypoxemic respiratory failure not related to COVID-19. [ABSTRACT FROM AUTHOR]

Patients with acute brain injury are vulnerable to secondary deterioration, which may go undetected by traditional monitoring. However, multimodal neuromonitoring of brain tissue oxygen tension (PbtO2) and energy metabolism may be able to detect such episodes. We report a retrospective, observational study of 94 patients with aneurysmal subarachnoid haemorrhage (SAH) or traumatic brain injury (TBI) who underwent multimodal neuromonitoring during admission. We examined the co-occurrence of pathological neuromonitoring values: elevated intracranial pressure (ICP, > 20 mmHg), inadequate cerebral perfusion pressure (CPP, < 60 mmHg), brain hypoxia (PbtO2 < 20 mmHg), and metabolic crisis (lactate/pyruvate ratio > 40 and a glucose level < 0.2 mmol/L in cerebral microdialysate). Mixed effects linear regression demonstrated significant associations between abnormal ICP/CPP, cerebral hypoxia and metabolic crisis. However, brain hypoxia occurred in 40% and 31% of observations in patients with SAH and TBI, respectively, despite normal concurrent values of ICP. Similarly, metabolic crisis was observed in 8% and 16% of measurements for SAH and TBI, respectively, despite a normal ICP. The pattern was identical for CPP. In conclusion, although all neuromonitoring variables are interrelated, brain hypoxia and metabolic crisis are common despite an absence of abnormalities in conventional monitoring. Multimodal neuromonitoring may help identify such episodes and guide individualised treatment. [ABSTRACT FROM AUTHOR]

In this paper, the dissolution behavior of crystal-originated particle (COP) in 300 mm Czochralski silicon under argon annealing was investigated. The latex sphere equivalent size distributions of defects along the depth direction in silicon wafers annealed under different conditions were quantified utilizing chemical–mechanical polishing and localized light scattering inspection. The interstitial oxygen concentration profiles were quantified by secondary ion mass spectrometry, and the distributions of oxygen precipitation within annealed wafers were obtained based on peak analysis. Furthermore, the classical theoretical model was employed to elucidate the depth-dependent dissolution of COP. Based on the initial COP sizes and oxygen concentrations, the relationship between COP sizes and depth after annealing was calculated. The depth distributions of defects obtained by combining the dissolution of COP from calculation with the changes of oxygen precipitation were found to be highly consistent with the measurement results. These findings could enhance the understanding of the mechanism of COP dissolution, which contributes to the production of defect-free silicon wafers for nanometre-scale integrated circuits. [ABSTRACT FROM AUTHOR]

A technique for the Monte Carlo simulation of the radiation in the carbon dioxide and nitrogen dissociation products in a shock wave is described: the rates of chemical reactions, as well as the excitation of electronic, vibration, and rotation levels of atoms and molecules of CO, CN, O2, and C2. A comparison of the results of numerical simulation and the experimental data obtained on shock tubes of the Institute of Mechanics of Moscow State University is presented. [ABSTRACT FROM AUTHOR]

A series of experiments are carried out on the shock tube of the Institute of Mechanics of Lomonosov Moscow State University to measure the evolution of radiation absorption in shock-heated oxygen in the wavelength range of 213–260 nm at a gas pressure of 1 Torr and shock wave velocities from 3.4 to 4.5 km/s. Based on a comparison of the experimental data with the results of calculations using the collision-radiation model, the influence of bound-bound and bound-unbound transitions in the Schumann–Runge system on the absorption properties of oxygen is analyzed. [ABSTRACT FROM AUTHOR]

Electric arc furnace (EAF) dust is an important secondary resource containing metals, such as zinc (Zn) and iron (Fe). Recovering Zn from EAF dust can contribute to resource recycling and reduce environmental impacts. However, the high chemical stability of ZnFe2O4 in EAF dust poses challenges to Zn recovery. To address this issue, a facile approach that involves oxygen-assisted chlorination using molten MgCl2 is proposed. This work focused on elucidating the role of O2 in the reaction between ZnFe2O4 and molten MgCl2. The results demonstrate that MgCl2 effectively broke down the ZnFe2O4 structure, and the high O2 atmosphere considerably promoted the separation of Zn from other components in the form of ZnCl2. The presence of O2 facilitated the formation of MgFe2O4, which stabilized Fe and prevented its chlorination. Furthermore, the excessive use of MgCl2 resulted in increased evaporation loss, and high temperatures promoted the rapid separation of Zn. Building on these findings, we successfully extracted ZnCl2-enriched volatiles from practical EAF dust through oxygen-assisted chlorination. Under optimized conditions, this method achieved exceptional Zn chlorination percentage of over 97% within a short period, while Fe chlorination remained below 1%. The resulting volatiles contained 85wt% of ZnCl2, which can be further processed to produce metallic Zn. The findings offer guidance for the selective recovery of valuable metals, particularly from solid wastes such as EAF dust. [ABSTRACT FROM AUTHOR]

Hydrographic observations and two-year current measurements revealed the flow around the Erimo Seamount between the Japan and Kuril trenches. Northward currents were observed to flow both around the seamount and on the eastern flank of the trench. Since the dissolved oxygen concentration of the former is higher than that of the latter, these currents correspond to the western and eastern branch currents of the deep western boundary current in the North Pacific, respectively. The western branch current forms a Taylor cap over the seamount, although during certain periods, it joins the eastern branch current. During such periods, a strong jet forms around the seamount and the Taylor cap is washed away. Such alternately intensified currents are consistent with previous observations of the Japan Trench. On the western flank of the trench, a southward current flows near the seafloor, while an eastward current is formed at a depth of 3360 m due to the confluence of the currents from north and south. [ABSTRACT FROM AUTHOR]

Current guidelines recommend oxygen (O2) supplementation in patients with pulmonary hypertension (PH), despite scarce data on long-term O2 therapy (LTOT). The aim of this prospective, randomized, controlled trial was to investigate the effect of LTOT in patients with precapillary PH on exercise capacity, clinical parameters and hemodynamics. Patients with precapillary PH under stable therapy and O2 desaturations at rest and/or during exercise were randomized to receive LTOT (≥ 16 h/day) or no O2 (control group) for 12 weeks. The control group was offered LTOT after 12 weeks. The primary endpoint changes of 6-minute walking distance (6MWD) from baseline to 12 weeks was hierarchically tested: (1) pre-post primary and secondary intervention (2) intervention vs. control group. Secondary endpoints included changes in clinical parameters. Twenty patients were randomized (women n = 14, age 67 ± 11.4 years, mean pulmonary arterial pressure 39.7 ± 12.5 mmHg, 70% functional class III). 6MWD significantly improved by 42.2 ± 34.20 m (p = 0.003) within 12 weeks LTOT. The intervention group significantly improved in 6MWD (38.9 ± 33.87 m) compared to the control group (− 12.3 ± 21.83 m, p = 0.015). No consistent between-group differences in other parameters were found. LTOT was well tolerated and led to significant improvement of 6MWD. The effect of LTOT should be investigated in larger controlled-trials. [ABSTRACT FROM AUTHOR]

This paper addresses a general nonhomogeneous incompressible cell-fluid Navier-Stokes model incorporating chemotaxis in a two or three-dimensional bounded domain. This model comprises two mass balance equations and two general momentum balance equations, specifically for the cell and fluid phases, combined with a convection-diffusion-reaction equation for oxygen. We establish the existence and uniqueness of a local strong solution under initial data that satisfy natural compatibility conditions. Additionally, we present a blow-up criterion for the strong solution. [ABSTRACT FROM AUTHOR]

Background: Posterior reversible encephalopathy syndrome (PRES) is an uncommon neurological disorder which is characterised by variable symptoms. The transient clinical condition may be underestimated and misdiagnosed as other conditions, especially, among pregnant women with severe preeclampsia, eclampsia, and HELLP (hemolysis, elevated liver enzymes, and low platelets) syndrome in the puerperium. We hereby contribute to the literature this rare complication and hightlight the appropriate management of PRES. Presentation case: A pregnant woman (gravida 3, parity 2) had a normal antenatal course. However, she was diagnosed with severe preeclampsia and HELLP syndrome at 29 weeks and 5 days of gestation. Therefore, she was indicated for a medical termination of pregnancy following a patient's consent at our tertiary referral hospital. Severely, the patient developed rapidly with altered mental health in early puerperium. In result, PRES was diagnosed based on a brain magnetic resonance imaging (MRI) evidence with typical findings. After a strict multidisciplinary management, the clinical condition improved after 5 days of onset and recovered completely after a 4-month follow-up without any sequelae. Conclusion: In summary, despite its rarity, clinicians ought to be knowledgeable and raise an aware of PRES during pregnancy. Importantly, a brain imaging modalities should be taken into account among pregnant women with neurological symptoms subsequent to severe preeclampsia. In addition to early diagnosis, a timely appropriate treatment with multidisciplinary team is strongly indicated. Further studies with a large case series are required for this uncommon entity. [ABSTRACT FROM AUTHOR]

The newly developed portable oxygen concentrator with an auto-demand oxygen delivery system (auto-DODS) automatically switches between 3 sensitivities according to the negative pressure gradient of inhalation and supplies oxygen only during inhalation. The aim of this study was to verify the effectiveness and safety of auto-demand devices compared with a continuous flow oxygen concentrator, during sleep, in a randomized crossover noninferiority trial. We alternatively used an auto-DODS or a continuous-flow oxygen concentrator, all night on separate days for HOT (Home Oxygen Therapy) patients with nocturnal hypoxemic symptoms. The primary endpoints were the mean value of oxygen saturation (SpO2) over the total sleep time. The secondary endpoints included the efficacy endpoints and the safety endpoints. Regarding the primary endpoint, the difference in SpO2 between the auto-DODS and continuous flow was 0.835%. Since the upper limit of this difference did not exceed 2.8, which was set as the noninferiority margin, it was shown that the auto-DODS did not reduce SpO2 by at least 2.8% on average compared to continuous flow. No equipment failure or exacerbation of disease was observed, confirming the safety of the auto-DODS during the night. [ABSTRACT FROM AUTHOR]

This study aims to clarify the effect of oxygen in shielding gas on weldability in the plasma-GMA (Gas Metal Arc) hybrid welding process of high-tensile strength steel plates. The difference in keyhole profile and bead formation, when the GMA shielding gas was pure Ar, Ar + 2% O2, or Ar + 20% CO2, was investigated for plate thicknesses of 6 and 9 mm for the first time. It was found that the weld beads were in good condition for 6 mm thickness plates for all shielding gases, which implied that the window of welding conditions for this thickness is wide. In contrast, for 9 mm thickness plates, a fully penetrated weld bead was achieved only in Ar + 20% CO2, and weld bead penetration in Ar + 20% CO2 is higher than in pure Ar and Ar + 2% O2 in the same welding condition. Due to decreased surface tension caused by sufficiently increased oxygen absorbed into the weld pool, the keyhole diameter increased to penetrate the bottom side of the plate, and the depressing weld pool surface under GMA allowed the heat input from the GMA to be directly applied to a deeper position. Consequently, the plasma-GMA hybrid welding process with Ar + 20% CO2 achieved a complete penetration for a plate of 9 mm thickness, owing to the effects of both phenomena. It proved a potential to increase penetrability in welding thicker plates by controlling oxygen content in shielding gas of GMA adequately. [ABSTRACT FROM AUTHOR]

Purpose of Review: What should a provider know about medications and other treatments in patients with cluster headache who have medical, psychiatric, and surgical comorbidities? What conversations should providers have with patients about living with and managing cluster headache? Recent Findings: While the number of treatments used in cluster headache is relatively small, numerous considerations were identified related to managing patients with comorbidities. Many of these touch on cardiac, cardiovascular, and cerebrovascular health, but full histories are needed to guide safe and effective treatment. Summary: Both older and newer treatments may be contraindicated in certain patients with cluster headache or should be considered carefully. In addition to incorporating medical, psychiatric, and surgical histories in the management plan, collaboration with other providers may be beneficial. Providers should also inquire about patient practices and discuss participation in clinical trials that might be a good fit for the individual. [ABSTRACT FROM AUTHOR]

Hypoxia is one of the predominant water quality issues affecting estuaries and coastal ecosystems, and its impact is often monitored using benthic macroinvertebrates. The M-AMBI (Multivariate AZTI Marine Biotic Index) is an index that meets the needs of small and large-scale monitoring as it is scalable. However, gaps remain as to the sensitivity of M-AMBI to hypoxia as few studies are available. Using Pensacola Bay in the northern Gulf of Mexico (USA) as a case study, we sought to evaluate the time scales over which benthic macrofauna respond to dissolved oxygen conditions from May through September 2017. Combined continuous DO monitoring and benthic sampling identified important differences in DO exposure on benthic habitat condition based on both the duration and frequency of low oxygen. We identified periods of 7 to 31 days as critical windows of exposure prior to a measurable benthic response, and that both duration and exposure to varying low oxygen conditions as well as the recovery period of oxygen to > 5 mg L−1 are important to benthic habitat health. While the duration of exposure to DO from < 2 mg L−1 to near anoxia remains an important factor in benthic health, benthic organisms can better tolerate periods of low oxygen when reoxygenation occurs after a short time interval. More research is needed to better quantify the relationship between oxygen stress and recovery on benthic habitats, particularly in systems where low DO exposure and recovery can vary over timescales of hours to days. [ABSTRACT FROM AUTHOR]

Hypoxia in coastal waters is a pressing ecological problem caused by continued eutrophication and climatic change that has widespread consequences for metazoan life and biogeochemical cycles. Numerous studies have investigated the controls on seasonal hypoxia formation and persistence in many of the world's large estuaries and coastal hypoxic zones, but far fewer studies have examined the controls on short-term oxygen variability that leads to diel-cycling hypoxia in shallow-water environments. We utilized a unique, comprehensive (181 stations) record of dissolved oxygen concentrations collected at shallow water sites (primarily < 2 m) at high frequency (15 min) throughout the estuarine complex of the Chesapeake Bay and its tributaries to quantify how internal and external variables co-varied with dissolved oxygen. We used a combination of time-series analysis, harmonic analysis, and machine learning (e.g., classification and regression trees (CART)) approaches to identify spatial patterns in major controls on oxygen variability and the duration of moderate hypoxia. We found that key controls on oxygen variability varied substantially over space. For example, photosynthetically active radiation (PAR) was a strong predictor of oxygen dynamics in the majority of mesohaline waters. In more fetch-exposed stations, wind strongly controlled hypoxic duration, but in eutrophic, inshore locations, chlorophyll a, or turbidity were often better predictors. Specifically, diel oxygen variability was muted in upstream regions characterized by high turbidity. The duration of low oxygen conditions, which we defined conservatively as less than 4.8 mg O2 L−1 (156 µM), was strongly controlled by temperature, and simple projections of regional warming and CART-derived oxygen thresholds suggest that the Bay could experience a 10% increase in this type of hypoxia duration by mid-to-late twenty-first century. The ratio of tidal to biological variability in oxygen was found to increase under conditions of higher turbidity, stronger wind, and lower salinity, but biological variability was typically a factor of two higher than tidal variability. Although chlorophyll-a generated high oxygen concentrations at some locations, those stations with exceptionally high chlorophyll a (> 30 µg L−1) were the most vulnerable to hypoxia. Because conventional water quality modeling frameworks are designed to capture hypoxia on relatively long time scales, these new insights can help inform updated oxygen models to support the management of shallow-water estuaries in the face of managed nutrient reductions and climate change. [ABSTRACT FROM AUTHOR]

Background: The step test provides valuable information on cardiorespiratory parameters such as maximal oxygen uptake and heart rate. Cardiorespiratory capacity is critical to health-related fitness, with heart rate recovery after exercise serving as a predictor of mortality risk. Main Body: The primary objective of this review was to identify trends, key contributors, and emerging themes in the step test literature through 2023 using the Web of Science Core Collection. Bibliometric data extraction and analysis were performed using a dedicated bibliometric software (VOSviewer). The analysis showed continued interest through 2021. The research categories highlight the multidisciplinary nature of the step test, covering cardiovascular systems, respiratory systems, sports sciences, and medicine. It has gained global attention, with 31 countries involved, with Brazil and the United States leading the way. The diversity of contributing nations is increasing, reflecting a growing global interest. With 111 journals involved, such as Respiratory Care and Medicine and Science in Sports and Exercise, step test research is spread across the academic landscape. With 761 contributing researchers, there is a collaborative and diverse community. The top 10 institutions, including the University of Alabama System and Monash University, illustrate the variety of settings in which step test studies are conducted. Step test studies span multiple disciplines, underscoring their adaptability. The clusters identified in this bibliometric analysis of the step test literature guide future research, suggesting avenues for refining protocols, exploring health implications, optimizing tests for specific conditions such as chronic obstructive pulmonary disease, and adapting step tests in diverse populations. Conclusions: Practical implications highlight the role of the step test in cardiovascular risk assessment, fitness monitoring, and rehabilitation. This broad review underscores the relevance of the step test in diverse settings, reflecting its adaptability and ease of application across occupational and clinical settings. Key Points: Global interest and research in the step test has grown significantly, with contributions from 31 countries and diverse disciplines, highlighting the adaptability and multidisciplinary relevance of the step test. Practical implications of the step test include its critical role in cardiovascular risk assessment, fitness monitoring, and rehabilitation. [ABSTRACT FROM AUTHOR]

Background: Circulatory shock, defined as decreased tissue perfusion, leading to inadequate oxygen delivery to meet cellular metabolic demands, remains a common condition with high morbidity and mortality. Rapid restitution and restoration of adequate tissue perfusion are the main treatment goals. To achieve this, current hemodynamic strategies focus on adjusting global physiological variables such as cardiac output (CO), hemoglobin (Hb) concentration, and arterial hemoglobin oxygen saturation (SaO2). However, it remains a challenge to identify optimal targets for these global variables that best support microcirculatory function. Weighting up the risks and benefits is especially difficult for choosing the amount of oxygen supplementation in critically ill patients. This review assesses the physiological basis for oxygen delivery to the tissue and provides an overview of the relevant literature to emphasize the importance of considering risks and benefits and support decision making at the bedside. Physiological premises: Oxygen must reach the tissue to enable oxidative phosphorylation. The human body timely detects hypoxia via different mechanisms aiming to maintain adequate tissue oxygenation. In contrast to the pulmonary circulation, where the main response to hypoxia is arteriolar vasoconstriction, the regulatory mechanisms of the systemic circulation aim to optimize oxygen availability in the tissues. This is achieved by increasing the capillary density in the microcirculation and the capillary hematocrit thereby increasing the capacity of oxygen diffusion from the red blood cells to the tissue. Hyperoxia, on the other hand, is associated with oxygen radical production, promoting cell death. Current state of research: Clinical trials in critically ill patients have primarily focused on comparing macrocirculatory endpoints and outcomes based on stroke volume and oxygenation targets. Some earlier studies have indicated potential benefits of conservative oxygenation. Recent trials show contradictory results regarding mortality, organ dysfunction, and ventilatory-free days. Empirical studies comparing various targets for SaO2, or partial pressure of oxygen indicate a U-shaped curve balancing positive and negative effects of oxygen supplementation. Conclusion and future directions: To optimize risk–benefit ratio of resuscitation measures in critically ill patients with circulatory shock in addition to individual targets for CO and Hb concentration, a primary aim should be to restore tissue perfusion and avoid hyperoxia. In the future, an individualized approach with microcirculatory targets will become increasingly relevant. Further studies are needed to define optimal targets. [ABSTRACT FROM AUTHOR]

Herein, a hydrothermal etching approach was used to generate an innovative CuS/O,N-CNT composite. The hydrothermal etching of g-C3N4 led to the creation of O,N-CNT, with ethanol as the oxygen source. The SEM and TEM characterizations confirmed the formation of CNT, whereas the XPS analysis proved the doping of oxygen and nitrogen in the CNT matrix along with the incorporation of CuS. Under sun irradiation, the produced CuS/O,N-CNT showed outstanding photocatalytic efficiency, eliminating methyl orange and methylene blue dyes with 97.21% and 98.11% efficacy, respectively. Adding hydrothermally etched O,N-CNT increased light absorption and charge migration kinetics, as can be studied from the UV-DRS and PL analysis; hence, the observed improvements in light absorption and charge transfer pathways contributed to the CuS/O,N-CNT composite's enhanced photocatalytic activity, indicating its potential for efficient elimination of organic contaminants under solar irradiation. The catalyst demonstrated high reusability performance up to six cycles and significantly degraded other dyes. Scavenger analysis, along with VB-XPS and UV-DRS analysis, aid in developing a photocatalytic mechanism that confirms the participation of hydroxyl and superoxide radicals in the degradation process. [ABSTRACT FROM AUTHOR]

Gold, nickel and platinum nanoparticles (NPs) have been synthesized by impregnating single-crystalline silicon surface with precursors (aqueous solutions of corresponding salts). The morphologies of the formed nanostructured coatings have been studied, and the electronic structures of the synthesized NPs, as well as their adsorption properties with respect to H2, O2, and H2O, have been determined. It has been found that oxidized nickel NPs are reduced by molecular hydrogen, while pure platinum NPs are oxidized by molecular oxygen already at room temperature. This phenomenon has not been observed for particles deposited in a similar way onto highly oriented pyrolytic graphite. In addition, it has been revealed that water molecules are formed on gold NPs as a result of the interaction between H2 and O2 in two stages, in contrast to the three-stage process (sequential exposure in H2, O2, and H2), which is inherent in NPs deposited onto graphite. Differences in the adsorption properties of NPs of the same type deposited onto graphite and silicon are associated with the adsorption of a significant amount of the test gases on the latter. [ABSTRACT FROM AUTHOR]

The effect of substitutional impurities on the formation energy of nitrogen vacancies and the oxygen defect on the N-sublattice as well as on the oxygen migration energy in TiN is studied using the projector augmented wave method. It has been shown that 4d transition metals with the exception of Zr and elements of IIIA and IVA groups excluding Al and Si reduce the formation energy of nitrogen vacancies. At the same time, regardless of the impurity, the formation energy of the oxygen defect has a negative value. The oxygen migration energy within the first coordination sphere is increased by almost all impurities, while metals of the middle of the 4dperiod slightly lower the migration barrier of oxygen, which allows it to move away from the impurity atom. The lower and upper limits of the temperature-dependent diffusion coefficient of oxygen in the doped titanium nitride are estimated. It has been revealed that almost all considered impurities reduce the diffusion coefficient mainly due to a change in the migration energy. [ABSTRACT FROM AUTHOR]

Objectives: To explore the oxygen metabolism level of different types of lesions in relapsing–remitting multiple sclerosis (RRMS) patients by oxygen extraction fraction (OEF) both cross-sectionally and longitudinally. Methods: Forty-six RRMS patients and forty-one healthy controls (HC) went MRI examination. The quantitative susceptibility mapping (QSM) and OEF map were reconstructed from a 3D multi-echo gradient echo sequence. MS lesions in white matter were classified as contrast-enhancing lesions (CELs) on post-gadolinium T1-weighted sequence, paramagnetic rim lesions (PRLs), hyperintense lesions and non-hyperintense lesions on QSM, respectively. The susceptibility and OEF of different types of lesions were compared. The susceptibility and OEF values were measured and compared among different types of lesions. Among these RRMS patients, seventeen had follow-up MRI and 232 lesions, and baseline to follow-up longitudinal changes in susceptibility and OEF were measured. Results: PRLs had higher susceptibility and lower OEF than CELs, hyperintense lesions, and non-hyperintense lesions. The hyperintense lesions had higher susceptibility and lower OEF than non-hyperintense lesions. In longitudinal changes, PRLs had susceptibility increased (P < 0.001) and OEF decreased (P < 0.001). The hyperintense lesions showed significant decreases in susceptibility (P = 0.020), and non-hyperintense lesions showed significant increases in OEF during follow-up (P = 0.005). Notably, hyperintense lesions may convert to PRLs or non-hyperintense lesions as time progresses, accompanied by changes of OEF and susceptibility in the lesions. Conclusion: This study revealed tissue damage and oxygen metabolism level in different types of MS lesions. The OEF may contribute to further understanding the evolution of MS lesions. [ABSTRACT FROM AUTHOR]

Based on a modified numerical model of the ionosphere and plasmasphere developed at the Institute of Solar–Terrestrial Physics (ISTP), Siberian Branch, Russian Academy of Sciences, the altitude profiles of the Ne electron density for the quiet and disturbed states of the thermosphere were calculated for the conditions of January 25, 2009, at a geographical point with the coordinates 52.4° N, 104.3° E (Irkutsk). The disturbed conditions were set by varying the temperature of neutral particles T in the thermosphere. At altitudes below 180 km and above 250 km, with an increase/decrease in T, an increase/decrease in Ne occurs. At altitudes of 180–250 km, the opposite picture is observed: an increase/decrease in T causes a decrease/increase in Ne. The opposite nature of the change in the Ne profile is associated with the influence of the ratio of concentrations of atomic oxygen and molecular nitrogen [O]/[N2] at the altitudes of region F. Quantitative estimates of the change in Ne at different altitudes with changes in the temperature of neutral particles were obtained. It has been established that a change in T by 1 K leads to a change in Ne by 0.2–0.3%. The modeling results are compared with observations of the peak electron density NmF2 obtained on the Irkutsk ionosonde during sudden stratospheric warming in January 2009. [ABSTRACT FROM AUTHOR]

The importance of emulsion zone formation in the basic oxygen steelmaking (BOF) process lies in its crucial role in enhancing refining efficiency. This study provides a comprehensive theoretical analysis of refining in BOF steelmaking, empowering steelmakers to optimize emulsion zone formation. By examining the contributions of decarburization, desiliconization, and dephosphorization from the emulsion zone, the study systematically investigates refining phenomena in distinct sections of the BOF converter, interconnected through recirculation streams. By utilizing FactSageTM and its macro-facilities, transient variations in metal and slag compositions, alongside varying terminal phosphorus levels for diverse emulsion zone dimensions, are quantified. Model findings highlight that emulsion and hotspot zones play roles in decarburization and desiliconization, while dephosphorization exclusively occurs within the emulsion zone. The model's projections for carbon, silicon, and phosphorus removals (wt pct) and metal bath temperature concur with data obtained from plant trials. This comprehensive analysis enhances our understanding of the BOF steelmaking process, enabling steelmakers to fabricate the required emulsion zone strategically for optimal refining efficiency. [ABSTRACT FROM AUTHOR]

Titanium is a metal with excellent physical and chemical properties. Although it is highly abundant in the earth's crust, the difficulty of its extraction makes it expensive and restrict its application on a large scale. It has become a world problem to develop a titanium smelting method with low cost and short process. In this research, TiH1.924 powder with a low oxygen content was produced by hydrogen-assisted magnesiothermic reduction at 650 °C for 2 hours. By optimizing the thermodynamic calculation method of Ti–O–H solid solution, the thermodynamic data of Ti–O, Ti–H, and Ti–O–H with different oxygen contents have been calculated. The results showed that the hydrogen in Ti–O–H has destabilizing effect on the oxygen in Ti–O lattice. Therefore, under hydrogen atmosphere, Mg can break the thermodynamic limit of deoxidation of Ti–O solid solution, obtaining a low oxygen content reduction product. In order to further reduce the oxygen content in the product, the mechanism of secondary oxidation of the titanium hydride product was investigated, leading to the conclusion that higher hydrogen content in titanium hydride can obviously enhance its anti-oxidation property. The research can provide theoretical support for the deep reduction of TiO2 using low-cost Mg powder to obtain titanium powder with a low oxygen content. [ABSTRACT FROM AUTHOR]

To establish the dissolution mechanism of palladium (Pd) in the FetO–SiO2–CaO–Al2O3–MgOsat slag system, the Pd solubility was measured at 1873 K (1600 °C) and oxygen partial pressure ranging from p O 2 = 1.0 × 10 - 8 atm to p O 2 = 1.0 × 10 - 6 atm . In the current slag system, the Pd solubility increases with increasing content of CaO and FeO, and decreases with increasing content of SiO2 and Al2O3. This solubility behavior is quantified by employing the modified Vee ratio, defined as (CaO+FeO)/(SiO2+Al2O3), the theoretical optical basicity and the activity of CaO in the slag. Thermodynamic analysis reveals that Pd stabilizes in the form of the ( PdO 2 3 - ) palladate complex ion in the present aluminosilicate melts. Based on this, the Pd dissolution reaction in the current slag system is proposed as follows: Pd (l) + 1 4 O 2 (g) + 3 2 O 2 - = (PdO 2 3 -) Combining the results from the present experiment and previous findings suggests that a well-designed slag system can effectively minimize Pd loss during the pyrometallurgical processing of industrial wastes containing Pd. By adjusting the modified Vee ratio, in which CaO and FeO promote Pd solubility in the slag, whereas SiO2 increases slag viscosity, it is possible to achieve optimal conditions. Therefore, we recommend implementing such an optimized slag system for pyrometallurgical treatment of Pd-containing industrial wastes, ensuring minimal Pd loss and maximizing resource recovery. [ABSTRACT FROM AUTHOR]

Examining the kinetics involved in the Argon Oxygen Decarburization (AOD) process, especially in the hotspot and emulsion zones within distinct reactors, can offer a deeper understanding of the refining mechanism in stainless-steelmaking. A predictive dynamic model has been formulated to estimate the effects of different refining processes, encompassing decarburization, desiliconization, demanganization, and chromium removal. The model includes a sub-model for heat loss calculation. The FactSage™ software, along with its macro programming capability, was utilized to incorporate thermochemical and kinetic information into the model. The model forecasts that the predominant chromium removal occurs within the hotspot zone, while carbon, silicon, and manganese removals occur in both the hotspot and emulsion zones. The predictions regarding the transient compositions of steel and slag, as well as the temperature of the steel bath, align with the plant data (Average of five heats), showcasing consistency. [ABSTRACT FROM AUTHOR]