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GaN grown via oxide vapor phase epitaxy (OVPE-GaN) can produce free-standing substrates with ultra-low resistivity because of the high doping concentration of oxygen. The bulk growth of OVPE-GaN is hindered by polycrystals generated during long-term growth. We have previously reported that thicker films can be grown by reducing the partial pressure of water vapor in the growth atmosphere with CH4. However, as CH4 is a dopant of carbon, a compensating acceptor, its addition may increase electrical resistance. In this study, we further investigated the effect of reducing water vapor partial pressure on polycrystals by combining Ga2O production (reaction of Ga and water vapor: a Ga–H2O system), which can reduce water vapor, with CH4 addition. However, CH4 addition to the Ga–H2O system increased polycrystal generation, possibly owing to the thermal decomposition of excess CH4. The properties of OVPE-GaN with CH4 addition were also evaluated. Although the CH4 addition resulted in high carbon doping, the carbon-doped OVPE-GaN maintained low resistivity. This is because the OVPE method involves three-dimensional growth with growth pits, and the growth pits leave behind low-resistivity high-oxygen-concentration regions. As the resistivity remains low even when CH4 is added in the OVPE method, both polycrystallization suppression and low resistivity can be achieved by selecting an appropriate CH4 flow rate. [ABSTRACT FROM AUTHOR]

Ultra-high temperature ceramics (UHTCs), most notably transition metal carbides and borides, exhibit melting temperatures exceeding 3000 °C, making them appropriate candidates to withstand the extreme temperatures (∼2000 °C) expected to occur at the leading edges of hypersonic vehicles. However, their propensity to react rapidly with oxygen limits their sustained application. The high entropy paradigm enables the exploration of novel UHTC compositions that may improve on the oxidation resistance of conventional refractory mono-carbides and -diborides. The oxidation kinetics of candidate high entropy group IV + V (HfZrTiTaNb)C and (HfZrTiTaNb)B2 materials were evaluated at 1500–1800 °C using Joule heating in one atmosphere 0.1%–1% oxygen/argon gas mixtures for times up to 15 min. Possible mechanisms based on the resulting complex time, temperature, and oxygen partial pressure dependencies are discussed. The carbides formed porous and intergranular oxides. Oxidation resistance was improved upon a continuous external scale formation. The diborides formed dense external scales and exhibited better oxidation resistance compared to the carbides. This improvement was attributed to the formation of liquid boria. Both compositions showed an unexpected reduction in material consumption at 1800 °C for all times tested, compared to results at lower temperatures. An in-depth analysis of the composition and morphology of the oxide scale and sub-surface regions for specimens tested at 1800 °C revealed that the formation of denser group IV-rich (Hf, Zr, Ti) oxides mitigated the formation of the otherwise detrimental liquid-forming group V (Ta, Nb) oxides, leading to the improved oxidation resistance. [ABSTRACT FROM AUTHOR]

Ultra-high temperature ceramics (UHTCs), most notably transition metal carbides and borides, exhibit melting temperatures exceeding 3000 °C, making them appropriate candidates to withstand the extreme temperatures (∼2000 °C) expected to occur at the leading edges of hypersonic vehicles. However, their propensity to react rapidly with oxygen limits their sustained application. The high entropy paradigm enables the exploration of novel UHTC compositions that may improve on the oxidation resistance of conventional refractory mono-carbides and -diborides. The oxidation kinetics of candidate high entropy group IV + V (HfZrTiTaNb)C and (HfZrTiTaNb)B2 materials were evaluated at 1500–1800 °C using Joule heating in one atmosphere 0.1%–1% oxygen/argon gas mixtures for times up to 15 min. Possible mechanisms based on the resulting complex time, temperature, and oxygen partial pressure dependencies are discussed. The carbides formed porous and intergranular oxides. Oxidation resistance was improved upon a continuous external scale formation. The diborides formed dense external scales and exhibited better oxidation resistance compared to the carbides. This improvement was attributed to the formation of liquid boria. Both compositions showed an unexpected reduction in material consumption at 1800 °C for all times tested, compared to results at lower temperatures. An in-depth analysis of the composition and morphology of the oxide scale and sub-surface regions for specimens tested at 1800 °C revealed that the formation of denser group IV-rich (Hf, Zr, Ti) oxides mitigated the formation of the otherwise detrimental liquid-forming group V (Ta, Nb) oxides, leading to the improved oxidation resistance. [ABSTRACT FROM AUTHOR]

Building on recent simulation work, it is demonstrated using molecular dynamics simulations of two-component fluid mixtures that the chemical contribution to the Soret effect in two-component nonideal fluid mixtures arises due to differences in how the partial pressures of the components respond to temperature and density gradients. Further insight is obtained by reviewing the connection between activity and deviations from Raoult's law in the measurement of the vapor pressure of a liquid mixture. A new parameter γ s S , defined in a manner similar to the activity coefficient, is used to characterize differences deviations from "ideal" behavior. It is then shown that the difference γ 2 S − γ 1 S is predictive of the sign of the Soret coefficient and is correlated to its magnitude. We hence connect the Soret effect to the relative volatility of the components of a fluid mixture, with the more volatile component enriched in the low-density, high-temperature region, and the less volatile component enriched in the high-density, low-temperature region. Because γ s S is closely connected to the activity coefficient, this suggests the possibility that measurement of partial vapor pressures might be used to indirectly determine the Soret coefficient. It is proposed that the insight obtained here is quite general and should be applicable to a wide range of materials systems. An attempt is made to understand how these results might apply to other materials systems including interstitials in solids and multicomponent solids with interdiffusion occurring via a vacancy mechanism. [ABSTRACT FROM AUTHOR]

The discovery of strontium niobate (SNO) as a potentially new transparent electrode has generated much interest due to its implications in various optoelectronic devices. Pristine SNO exhibits exceptionally low resistivity (∼10−4 Ω cm) at room temperature. However, this low resistivity occurs due to large number of carrier concentration in the system, which significantly affects its optical transparency (∼40%) in the visible range and hinders its practical applications as a transparent electrode. Here, we show that modulating the growth kinetics via oxygen manipulation is a feasible approach to achieve the desired optoelectronic properties. In particular, epitaxial (001) SNO thin films are grown on (001) lanthanum aluminate by pulsed laser deposition at different oxygen partial pressures and are shown to improve the optical transparency from 40% to 72% (λ = 550 nm) at a marginal cost of electrical resistivity from 2.8 to 8.1 × 10−4 Ω cm. These changes are directly linked with the multi-valence Nb-states, as evidenced by x-ray photoelectron spectroscopy. Furthermore, the defect-engineered SNO films exhibit multiple electronic phases that include pure metallic, coexisting metal-semiconducting-like, and pure semiconducting-like phases as evidenced by low-temperature electrical transport measurements. The intriguing metal-semiconducting coexisting phase is thoroughly analyzed using both perpendicular and angle-dependent magnetoresistance measurements, further supported by a density functional theory-based first-principles study and the observed feature is explained by the quantum correction to the conductivity. Overall, this study shows an exciting avenue for altering the optical and transport properties of SNO epitaxial thin films for their practical use as a next-generation transparent electrode. [ABSTRACT FROM AUTHOR]

BackgroundInfants with hypoxic-ischemic encephalopathy are often treated with therapeutic hypothermia and high-frequency ventilation. Fluctuations in PaCO2 during therapeutic hypothermia are associated with poor neurodevelopmental outcomes. Transcutaneous CO2 monitors offer a noninvasive estimate of PaCO2 represented by transcutaneously measured partial pressure of carbon dioxide (PtcCO2 ). We aimed to assess the precision between PtcCO2 and PaCO2 values in neonates undergoing therapeutic hypothermia.MethodsThis was a retrospective chart review of 10 neonates who underwent therapeutic hypothermia requiring respiratory support over 2 y. A range of 2-27 simultaneous PtcCO2 and PaCO2 pairs of measurements per neonate were analyzed via linear mixed models and a Bland-Altman plot for multiple observations per neonate.ResultsA linear mixed-effect model demonstrated that PtcCO2 and PaCO2 (controlling for sex) were similar. The 95% CI of the mean difference ranged from -2.3 to 5.7 mm Hg (P = .41). However, precision was poor as the PtcCO2 ranged from > 18 mm Hg to < 13 mm Hg than PaCO2 values for 95% of observations.ConclusionsThe neonates' PtcCO2 was as much as 18 mm Hg higher to 13 mm Hg lower than the PaCO2 95% of the time. Transcutaneous CO2 monitoring may not be a good trending tool, nor is it appropriate for estimating PaCO2 in patients undergoing therapeutic hypothermia.

We report on a thermodynamic analysis of oxide vapor phase epitaxy (OVPE) of GaN. We first calculate equilibrium partial pressures of gases for the initial partial pressures of Ga2O, NH3, and H2 as well as the growth temperature. To estimate the growth rate of a GaN crystal, we then define the supersaturation amount determined by the equilibrium and initial partial pressures. In the calculation, the growth rate is significantly influenced by the initial partial pressures of Ga2O and NH3, while it is almost independent of the initial partial pressure of H2 and the growth temperature. Subsequently, we experimentally grow GaN crystals under same conditions as in the thermodynamic analysis. In the range of conditions in this work, the experimental growth rates are nearly consistent with the growth rates predicted by the thermodynamic analysis for all experimental parameters. Thus, the results showed that a high value of the supersaturation amount is advantageous for high-speed growth. Furthermore, we define the supersaturation ratio and investigate the correlation between this parameter and the surface coverage of the polycrystal. The surface coverage of the polycrystal is confirmed to roughly decrease as the value of the supersaturation ratio decreases. Thus, the results showed that a low value of the supersaturation ratio is advantageous for polycrystal-free growth. Finally, we use the thermodynamic analysis to explore the optimal conditions for high-speed and polycrystal-free growth. This revealed that the optimal OVPE growth conditions are both a high partial pressure of Ga2O and a low partial pressure of NH3. [ABSTRACT FROM AUTHOR]

Hydrogen embrittlement (HE) is a significant challenge to the safe operation of hydrogen-blended natural gas pipelines. The mechanical properties of X80 steel were studied after H 2 pre-charging followed by mechanical properties tests and fracture morphologies observation. Results indicated that the hydrogen saturation time of X80 steel was roughly 48 h. H 2 pre-charging induced a decline in strength, plasticity, and fatigue properties, while hydrogen-assisted fatigue crack growth occurred during the early stage of fatigue crack growth rate tests. Additionally, the fracture morphologies transited from primary microvoid coalescence to a mixed mode characterized by ductile dimples and quasi-cleavage planes with increasing hydrogen. The HE susceptibility increased with increasing hydrogen partial pressure and decreasing loading frequency, but there existed a critical value (6 × 10−7 s−1) for the strain rate effect on the HE susceptibility. Under H 2 pre-charging conditions, the predominant HE mechanism was the hydrogen-enhanced local plasticity (HELP) mediated hydrogen-enhanced decohesion (HEDE) mechanism. • Permeation parameters of X80 steel were obtained through H 2 permeation tests. • The mechanical properties of hydrogen pre-charged X80 steel were obtained. • 6 × 10−7 s−1 was determined as the critical strain rate to HE susceptibility. • The predominant HE mechanism under hydrogen pre-charging conditions was analyzed. [ABSTRACT FROM AUTHOR]

A hot spot which is a glowing orange local area appears in RE Ba 2 Cu 3 O y (RE : rare earth) ceramic rods when a voltage higher than a certain value is applied at room temperature. After the hot spot appears, the oxygen partial pressure in the ambient atmosphere changes the current through the rod, which can be used as an oxygen sensor without the need for a heating system. In this study, the authors investigated the oxygen-sensing characteristics and the power-saving effect of the sandwich structure in which the sensor layer was stacked between insulation layers. The sample rods were prepared by the solid-state reaction at 960 °C. Materials of 5 mol% Nd 2 BaCuO 5 -added Nd 1.4 Ba 1.6 Cu 3 O y and 20 mol% Nd 1.4 Ba 1.6 Cu 3 O y -added Nd 2 BaCuO 5 were used for the sensor layer and the insulation layer, respectively. The sensitivity to the oxygen increased with increasing voltage applied to the rod. Under the condition where 17.8 V was applied to the rod with the sandwich structure and 6.6 V to the rod with the monolithic structure, the sensitivities of both rods were almost the same. The sandwich structure had a reduced current value and consumed approximately 26 % less power than the monolithic structure. The response time for the sandwich structure and the monolithic structure were comparable, meaning that the insulation layer did not impair the response time. [ABSTRACT FROM AUTHOR]

P-bromophenol (4-BP) is a toxic halogenated phenolic organic compound. The conventional treatment processes for 4-BP elimination are costly and inefficient, with complete mineralization remaining a challenge for water treatment. To overcome these limitations, we investigated the treatment of 4-BP in a membrane biofilm reactor (MBfR) using hydrogen as an electron donor. The pathway of 4-BP degradation within the H2-MBfR was investigated through long-term operational experiments by considering the effect of nitrate and 4-BP concentrations, hydrogen partial pressure, static experiments, and microbial community diversity, which was studied using 16S rRNA. The results showed that H2-MBfR could quickly remove approximately 100% of 4-BP (up to 20 mg/L), with minimal intermediate product accumulation and 10 mg/L of nitrate continuously reduced. The microbial community structure showed that the presence of H2 created an anaerobic environment, and Thauera was the dominant functional genus involved in the degradation of 4-BP. The genes encoding related enzymes were further enhanced. This study provides an economically viable and environmentally friendly bioremediation technique for water bodies that contain 4-BP and nitrates. [ABSTRACT FROM AUTHOR]

The negative electric potential difference observed in a YSZ-based thin film potentiometric sensor at a low operating temperature of 673 K is investigated. The multilayered sensor is grown sequentially using pulsed laser deposition at 998 K with Cu-Cu2O reference electrode, YSZ electrolyte and Pt as working electrode respectively. The thickness of the Cu-Cu2O reference layer is a critical factor in thin film sensors as the Pt3O4 phase stabilized along with Cu-Cu2O can reach the YSZ interface. XRD, μ- Raman and XPS confirm the formation of the Pt3O4 phase on the reference side along with the Cu-Cu2O layer. However, the pure Pt3O4 phase could not be stabilized in the thin film without Cu-Cu2O. The presence of the Pt3O4 phase on the reference side generates a Pt-Pt3O4 reference couple with an equilibrium oxygen partial pressure of ~ 104 ppm higher than the sample oxygen pressure of 10-103 ppm giving rise to a negative electric potential difference with a sensitivity of -7.5 mV/decade. [ABSTRACT FROM AUTHOR]

Background: The global incidence of liver diseases is rising, yet there remains a dearth of precise research models to mimic these diseases. The use of normothermic machine perfusion (NMP) to study diseased livers recovered from liver transplantation (LT) recipients presents a promising avenue. Accordingly, we have developed a machine perfusion system tailored specifically for the human whole diseased livers and present our experience from the NMP of diseased livers. Methods: Six diseased livers recovered from LT recipients with different diagnoses were collected. The diseased livers were connected to the machine perfusion system that circulated tailored perfusate, providing oxygen and nutrients. The pressure and flow of the system were recorded, and blood gas analysis and laboratory tests of perfusate and bile were examined to analyze the function of the diseased livers. Liver tissues before and after NMP were collected for histological analysis. Results: Experiments showed that the system maintained the diseased livers in a physiological state, ensuring stable hemodynamics and a suitable partial pressure of oxygen and carbon dioxide. The results of blood gas analysis and laboratory tests demonstrated a restoration and sustenance of metabolism with minimal damage. Notably, a majority of the diseased livers exhibited bile production continuously, signifying their vivid functional integrity. The pathological characteristics remained stable before and after NMP. Conclusion: We successfully established the machine perfusion system tailored specifically for diseased human whole livers. Through the application of this system, we have developed a novel in vitro model that faithfully recapitulates the main features of human liver disease. This model holds immense promise as an advanced disease modeling platform, offering profound insights into liver diseases and potential implications for research and therapeutic development. [ABSTRACT FROM AUTHOR]

To compare the efficacy of inhaled salbutamol with salmeterol for the treatment of arterial hypoxaemia in anaesthetized horses. Prospective, randomized, clinical study. A total of 108 client-owned horses (American Society of Anesthesiologists status I–V) anaesthetized for elective and emergency procedures. Horses were premedicated with acepromazine [intramuscularly 0.1 mg kg–1 or intravenously (IV) 0.05 mg kg–1] and xylazine (0.6 mg kg–1 IV). Midazolam (0.06 mg kg–1 IV) and ketamine (2.2 mg kg–1 IV) were combined to induce anaesthesia, and isoflurane in oxygen/air mixture (inspired oxygen fraction 0.7) was used for maintenance of anaesthesia. Mechanical ventilation was initiated without delay using the following ventilator settings: tidal volume 10 mL kg–1, respiratory rate 8 breaths minute–1, inspiratory-to-expiratory time ratio 1:2, no positive end-expiratory pressure. If arterial blood gas analysis revealed PaO 2 < 100 mmHg (13.3 kPa), the administration of either inhaled salbutamol (2 μg kg–1) or salmeterol (0.5 μg kg–1) was randomly assigned Blood gas analysis was repeated 15 and 30 minutes after treatment. The intervention was considered successful when PaO 2 after treatment ≥ 1.2 × PaO 2 before treatment (i.e. ≥20% increase). PaO 2 at 15 and 30 minutes was compared between groups using Mann–Whitney U test; p < 0.05 was considered significant. Of the 108 horses, 60 were administered salbutamol, 65% and 60% responded successfully at 15 and 30 minutes, increasing their initial PaO 2 by 38% and 44%, respectively. The other 48 horses were administered salmeterol, 35% responded successfully at 15 and 30 minutes, increasing their initial PaO 2 by 3% and 4%, respectively. PaO 2 was significantly higher after salbutamol than after salmeterol at 15 and 30 minutes. Using the described protocol, inhaled salbutamol was more effective than salmeterol in improving PaO 2 in anaesthetized horses with value < 100 mmHg (13.3 kPa). [ABSTRACT FROM AUTHOR]

Background: Sport-related concussions are a complex injury requiring multifaceted assessment, including physical exertion. Currently, concussion testing relies primarily on a treadmill-based protocol for assessing exertion-related symptoms in persons after concussion. This study compared a modified cycle protocol (Calgary Concussion Cycle Test [CCCT]) with the clinically adopted standard, the Buffalo Concussion Treadmill Test (BCTT), across multiple physiological parameters. Hypothesis: Treadmill and cycle matched workload protocols would produce similar results for cerebral blood velocity, mean arterial pressure (MAP), and end-tidal carbon dioxide partial pressure (PETCO2), but heart rate (HR) and oxygen consumption (VO2) would be higher on the treadmill than the cycle modality. Study Design: Crossover study design. Level of Evidence: Level 3. Methods: A total of 17 healthy adults (8 men, 9 women; age, 26 ± 3 years; body mass index, 23.8 ± 2.7 kg/m2) completed the BCTT and CCCT protocols, 7 days apart in a randomized order. During both exertional protocols, the physiological parameters measured were middle cerebral artery mean blood velocity (MCAv), MAP, PETCO2, VO2, and HR. Analysis of variance with effect size computations, coefficient of variation, and Bland-Altman plots with 95% limits of agreement were used to compare exercise tests. Results: The BCTT and CCCT produced comparable results for both male and female participants with no significant differences for average MCAv, MAP, and PETCO2 (all P > 0.05; all generalized eta squared [η2G] < 0.02 [negligible]; P value range, 0.29-0.99) between stages. When accounting for exercise stage and modality, VO2 (P < 0.01) and HR (P < 0.01) were higher on the treadmill compared with the cycle. Aside from the final few stages, all physiology measures displayed good-to-excellent agreeability/variability. Conclusion: The CCCT was physiologically similar to the BCTT in terms of MCAv, PETCO2, and MAP; however, HR and VO2 differed between modalities. Clinical Relevance: Providing a cycle-based modality to exertional testing after injury may increase accessibility to determine symptom thresholds in the future. [ABSTRACT FROM AUTHOR]

Background: Cerebrovascular reactivity (CVR) is a measure of the change in cerebral blood flow (CBF) in response to a vasoactive challenge. It is a useful indicator of the brain's vascular health. Purpose: To evaluate the factors that influence successful and unsuccessful CVR examinations using precise arterial and end‐tidal partial pressure of CO2 control during blood oxygen level–dependent (BOLD) MRI. Study Type: Retrospective. Subjects: Patients that underwent a CVR between October 2005 and May 2021 were studied (total of 1162 CVR examinations). The mean (±SD) age was 46.1 (±18.8) years, and 352 patients (43%) were female. Field Strength/Sequence: 3 T; T1‐weighted images, T2*‐weighed two‐dimensional gradient‐echo sequence with standard echo‐planar readout. Assessment: Measurements were obtained following precise hypercapnic stimuli using BOLD MRI as a surrogate of CBF. Successful CVR examinations were defined as those where: 1) patients were able to complete CVR testing, and 2) a clinically useful CVR map was generated. Unsuccessful examinations were defined as those where patients were not able to complete the CVR examination or the CVR maps were judged to be unreliable due to, for example, excessive head motion, and poor PETCO2 targeting. Statistical Analysis: Successful and unsuccessful CVR examinations between hypercapnic stimuli, and between different patterns of stimulus were compared with Chi‐Square tests. Interobserver variability was determined by using the intraclass correlation coefficient (P < 0.05 is significant). Results: In total 1115 CVR tests in 662 patients were included in the final analysis. The success rate of generating CVR maps was 90.8% (1012 of 1115). Among the different hypercapnic stimuli, those containing a step plus a ramp protocol was the most successful (95.18%). Among the unsuccessful examinations (9.23%), most were patient related (89.3%), the most common of which was difficulty breathing. Data Conclusion: CO2‐BOLD MRI CVR studies are well tolerated with a high success rate. Evidence Level: 4 Technical Efficacy: Stage 3 [ABSTRACT FROM AUTHOR]

Background Methods Results Conclusion High‐flow nasal oxygenation is reported to prolong duration of apnea while maintaining adequate oxygen saturation with the mouth closed. Also, buccal oxygenation is known to have similar effects in obese adults. We compared the effect of these two methods on prolongation of acceptable apnea time in pediatric patients with their mouth open.Thirty‐eight patients, aged 0–10 years were randomly allocated to either the high‐flow nasal oxygenation group (n = 17) or the buccal oxygenation group (n = 21). After induction of anesthesia including neuromuscular blockade, manual ventilation was initiated until the expiratory oxygen concentration reached 90%. Subsequently, ventilation was paused, and the patient's head was extended, and mouth was opened. The HFNO group received 2 L·min−1·kg−1 of oxygen, and the BO group received 0.5 L·min−1·kg−1 of oxygen. We set a target apnea time according to previous literature. When the apnea time reached the target, we defined the case as “success” in prolongation of safe apnea time and resumed ventilation. When the pulse oximetry decreased to 92% before the target apnea time, it was recorded as “failure” and rescue ventilation was given.The success rate of safe apnea prolongation was 100% in the high‐flow nasal oxygenation group compared to 76% in the buccal oxygenation group (p = .04). Oxygen reserve index, end‐tidal or transcutaneous carbon dioxide partial pressure, and pulse oximetry did not differ between groups.High‐flow nasal oxygenation is effective in maintaining appropriate arterial oxygen saturation during apnea even in children with their mouth open and is superior to buccal oxygenation. Buccal oxygenation may be a good alternative when high‐flow nasal oxygenation is not available. [ABSTRACT FROM AUTHOR]

Background: A combination of prone positioning (PP) and venovenous extracorporeal membrane oxygenation (VV-ECMO) is safe, feasible, and associated with potentially improved survival for severe acute respiratory distress syndrome (ARDS). However, whether ARDS patients, especially non-COVID-19 patients, placed in PP before VV-ECMO should continue PP after a VV-ECMO connection is unknown. This study aimed to test the hypothesis that early use of PP during VV-ECMO could increase the proportion of patients successfully weaned from ECMO support in severe ARDS patients who received PP before ECMO. Methods: In this prospective observational study, patients with severe ARDS who were treated with VV-ECMO were divided into two groups: the prone group and the supine group, based on whether early PP was combined with VV-ECMO. The proportion of patients successfully weaned from VV-ECMO and 60-day mortality were analyzed before and after propensity score matching. Results: A total of 165 patients were enrolled, 50 in the prone and 115 in the supine group. Thirty-two (64%) and 61 (53%) patients were successfully weaned from ECMO in the prone and the supine groups, respectively. The proportion of patients successfully weaned from VV-ECMO in the prone group tended to be higher, albeit not statistically significant. During PP, there was a significant increase in partial pressure of arterial oxygen (PaO2) without a change in ventilator or ECMO settings. Tidal impedance shifted significantly to the dorsal region, and lung ultrasound scores significantly decreased in the anterior and posterior regions. Forty-five propensity score-matched patients were included in each group. In this matched sample, the prone group had a higher proportion of patients successfully weaned from VV-ECMO (64.4% vs. 42.2%; P = 0.035) and lower 60-day mortality (37.8% vs. 60.0%; P = 0.035). Conclusions: Patients with severe ARDS placed in PP before VV-ECMO should continue PP after VV-ECMO support. This approach could increase the probability of successful weaning from VV-ECMO. Trial Registration: ClinicalTrials.Gov: NCT04139733. Registered 23 October 2019. [ABSTRACT FROM AUTHOR]

Insufficient spatiotemporal coverage of partial pressure of CO2 (p CO2) observations has hindered precise studies of the coastal carbon cycle along the North American Atlantic Coastal Ocean Margin (NAACOM). Earlier p CO2-products have encountered difficulties in accurately capturing the heterogeneity of regional variations and decadal trends of p CO2 in the NAACOM. This study developed a regional reconstructed p CO2-product for the NAACOM (Reconstructed Coastal Acidification Database- p CO2, or ReCAD-NAACOM- p CO2) using a two-step approach combining random forest regression and linear regression. The product provides monthly p CO2 data at 0.25° spatial resolution from 1993 to 2021, enabling investigation of regional spatial differences, seasonal cycles, and decadal changes in p CO2. The observation-based reconstruction was trained using Surface Ocean CO2 Atlas (SOCAT) observations as ground-truth values, with various satellite-derived and reanalysis environmental variables known to control sea surface p CO2 as model inputs. The product shows high accuracy during the model training, validation, and independent test phases, demonstrating robustness and capability to accurately reconstruct p CO2 in regions or periods lacking direct observational data in the NAACOM. Compared with all the observation samples from SOCAT, the p CO2-product yields a determination coefficient of 0.83, a root-mean-square error of 18.64 µatm, and an accumulative uncertainty of 23.83 µatm. The ReCAD-NAACOM- p CO2 product demonstrates its capability to resolve seasonal cycles, regional-scale variations, and decadal linear trends of p CO2 along the NAACOM. This new product provides reliable p CO2 data for more precise studies of coastal carbon dynamics in the NAACOM region. The dataset is publicly accessible at https://doi.org/10.5281/zenodo.11500974 (Wu et al., 2024a) and will be updated regularly. [ABSTRACT FROM AUTHOR]

Objectives: To assess whether nasal breathing improves exercise ventilatory efficiency in patients with heart failure (HF) or chronic coronary syndromes (CCS). Background: Exercise inefficient ventilation predicts disease progression and mortality in patients with cardiovascular diseases. In healthy people, improved ventilatory efficiency with nasal compared to oral breathing was found. Methods: Four study groups were recruited: Patients with HF, patients with CCS, old (age=45 years) and young (age 20-40 years) healthy control subjects. After a 3-min warm-up, measurements of 5 min with once nasal and once oral breathing were performed in randomized order at 50% peak power on cycle ergometer. Ventilation and gas exchange parameters measured with spiroergometry were analysed by Wilcoxon paired-sample tests and linear mixed models adjusted for sex, height, weight and test order. Results: Groups comprised 15 HF, CCS, and young control and 12 old control. Ventilation/carbon dioxide production (_VE/_ VCO2), ventilation (_VE), breathing frequency (fR), and end-tidal oxygen partial pressure (PETO2) were significantly lower and tidal volume and end-tidal carbon dioxide partial pressure (PETCO2) significantly higher during nasal compared to oral breathing in all groups, with large effect sizes for most parameters. For patients with HF, median _VE/V_CO2 was 35% lower, fR 26% lower, and PETCO2 10% higher with nasal compared to oral breathing, respectively. Exercise oscillatory ventilation (EOV) was present in 6 patients and markedly reduced with nasal breathing. Conclusion: Nasal breathing during submaximal exercise significantly improved ventilatory efficiency and abnormal breathing patterns (rapid shallow breathing and EOV) in 80% of our patients with HF and CCS. [ABSTRACT FROM AUTHOR]

Electrical machines for transportation applications are subjected to harsh environmental conditions during their operations. Partial discharge (PD), which is one of the main reasons for insulation failure, is greatly affected by ambient conditions (i.e., temperature, pressure, and humidity). Countless efforts are made for a comprehensive understanding of the physics of PD under variable environmental factors. This paper aims to review recent works addressing temperature, pressure, and humidity impact on PD activity. The main content of the paper is organized into three sections dealing with each environmental factor. In every section, relevant publications are reviewed considering the type of samples tested, voltage waveform applied, mutual effects, and the most common PD modeling strategies used. The applicability of the PD measurements for PD risk assessment is also discussed. Based on the review, the current progress in understanding the environmental effects on the PD inception mechanism and PD characteristics is presented and discussed in detail, and future research trends in this field are outlined. [ABSTRACT FROM AUTHOR]

The development of metal–organic frameworks for carbon dioxide (CO2) capture has drawn considerable interest among researchers with MIL-101(Cr) gaining significance owing to its high stability. This paper investigates the one-step synthesis of MIL-101-NH2(Cr) by using guanidine hydrochloride as a mediator under relatively mild conditions (aqueous phase, reaction temperature of 120 °C, and without the use of mineralization agents such as hydrofluoric acid). MIL-101-NH2(Cr) not only exhibited a high specific surface area with a Lewis-base site-rich ligand but also possessed a good CO2 adsorption capacity of 3.96 mmol/g at 1 bar. Furthermore, diethylenetriamine (DETA) was loaded into MIL-101-NH2(Cr) to design a new CO2 adsorbent DETA@MIL-101-NH2(Cr). The loaded material maintained the original structure and also displayed an improved adsorption capacity of 0.29 mmol/g under low (< 0.11 bar) CO2 partial pressure. The absorbents possessed good selectivity, stability, and recyclability which make them ideal candidates for CO2 capture. [ABSTRACT FROM AUTHOR]

Oxygen conditions in the lung determine downstream organ functionality by setting the partial pressure of oxygen, regulating the redox homeostasis and by activating mediators in the lung that can be propagated in the blood stream. Examples for such mediators are secreted soluble or vesicle-bound molecules (proteins and nucleic acids) that can be taken up by remote target cells impacting their metabolism and signaling pathways. MicroRNAs (miRNAs) have gained significant interest as intercellular communicators, biomarkers and therapeutic targets in this context. Due to their high stability in the blood stream, they have also been attributed a role as "memory molecules" that are able to modulate gene expression upon repeated (stress) exposures. In this study, we aimed to identify and quantify released miRNAs from lung microvascular endothelial cells in response to different oxygen conditions. We combined next-generation sequencing (NGS) of secreted miRNAs and cellular mRNA sequencing with bioinformatic analyses in order to delineate molecular events on the cellular and extracellular level and their putative interdependence. We show that the identified miRNA networks have the potential to co-mediate some of the molecular events, that have been observed in the context of hypoxia, hyperoxia, intermittent hypoxia and intermittent hypoxia/hyperoxia. [ABSTRACT FROM AUTHOR]

Previously, a strategy for doping MIEC perovskites ABO 3-δ with highly charged cations B5+ (Nb, Ta) and B6+ (Mo, W) was developed. The doping strategy is based on the idea that strontium ferrite/cobaltite-based perovskites are ferroelastic, whereas highly charged cations are ferroactive species. An increase in the concentration of the dopant leads to a reduction in the size of the domains of the ferroelastic phase down to the nanoscale. This resulted in the smearing of phase transitions with the formation of the highly conductive glassy state. Tantalum-doped lanthanum-strontium-ferrite perovskite (La 0.6 Sr 0.4 Fe 1-x Ta x O 3-δ , LSFTx) was prepared via solid-state reaction using chemically pure oxide powders of La 2 O 3 , SrCO 3 , Fe 2 O 3 , and Ta 2 O 5 , followed by calcination and sintering up to 1350 °C. The structural and surface properties were examined using X-ray diffraction and a scanning electron microscope. The original oxygen partial pressure relaxation (OPPR) method was used to study the kinetic properties of LSFTx. Continuous equilibrium phase diagram "T – pO 2 – δ" first obtained by oxygen release technique for composition LSFT3.5. Power law dependencies of the kinetic properties on the oxygen partial pressure are presented. [ABSTRACT FROM AUTHOR]

The exchange of trace gases between the atmosphere and the ocean plays a key role in the Earth's climate. Fluxes at the air-sea interface are affected mainly by wind blowing over the ocean and seawater temperature and salinity changes. This study aimed to quantify the use of CO 2 partial pressure (pCO 2 ) measurements at different depths (1, 5, and 10 m) in ocean surface layers to determine CO 2 fluxes (FCO 2 ) and to investigate the impacts of wind-sheltered and wind-exposed regions on the carbon budget. Vertical profiles of temperature, salinity, and pCO 2 were considered during a daily cycle. pCO 2 profiles exhibited relatively high values during sunny hours, associated with relatively high sea temperatures. However, the largest FCO 2 corresponded with higher wind speeds. Estimated fluxes between measurements at 1 and 10 m depths decreased by 71% in the sheltered region and 44% in the exposed region. According to the SOCAT dataset, at a depth of 5 m, the Atlantic basin emits approximately 0.29 Tg month - 1 of CO 2 to the atmosphere; nevertheless, our estimates suggest that FCO 2 at the surface is 12.02 Tg month - 1 , which is 97.6% greater than that at 5 m depth. Therefore, future studies should consider sampling depth to adequately estimate the FCO 2 . [ABSTRACT FROM AUTHOR]

Hypoxia is an important feature of the tumor microenvironment (TME) of most solid tumors, and it is closely linked to cancer cell proliferation, therapy resistance, and the tumor immune response. Herein, we describe a method for hypoxia-induced heterogeneous oxygen distribution in xenograft tumors based on phosphorescence imaging microscopy (PLIM) using intravascular and intracellular oxygen probes. We synthesized Ir(III) complexes with polyethylene glycol (PEG) units of different molecular weights into the ligand as intravascular oxygen probes, BTP-PEGm (m = 2000, 5000, 10000, 20000). BTP-PEGm showed red emission with relatively high emission quantum yield and high oxygen sensitivity in saline. Cellular and in vivo experiments using these complexes revealed that BTP-PEG10000 was the most suitable probe in terms of blood retention and ease of intravenous administration in mice. PLIM measurements of xenograft tumors in mice treated with BTP-PEG10000 allowed simultaneous imaging of the tumor microvasculature and quantification of oxygen partial pressures. From lifetime images using the red-emitting intracellular oxygen probe BTPDM1 and the green-emitting intravascular fluorescent probe FITC-dextran, we demonstrated hypoxic heterogeneity in the TME with a sparse vascular network and showed that the oxygen levels of tumor cells gradually decreased with vascular distance. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the efficacy of triple inhaled therapy, a combination of inhaled glucocorticoids, long-acting muscarinic antagonists, and long-acting β2 agonists in managing acute exacerbations of chronic obstructive pulmonary disease (COPD). Methods: Medical data of 100 patients with acute exacerbation of COPD admitted to Shaoxing Second Hospital, Shaoxing, China between January 2020 to December 2022 was collected and retrospectively analyzed. The patients were randomized into control (n = 50) and study groups (n = 50). Control group received budesonide/formoterol inhalers while the study group received triple inhaled therapy (budesonide/glycopyrronium/formoterol inhalers). Arterial blood gas, pulmonary function, immune function, adverse effects, and efficacy were evaluated. Results: The study group exhibited significantly higher pH, partial pressure of arterial oxygen (PaO2), and lower partial pressure of carbon dioxide (PaCO2) compared to control group (p < 0.001). Furthermore, the study group showed significantly higher levels of pulmonary function and immune function indices compared to control group (p < 0.001). There was no significant difference in incidence of adverse reactions between the two groups (p > 0.05). The study group was associated with higher clinical efficacy compared to the control group (p < 0.05). Conclusion: Triple inhaled therapy significantly alleviates the clinical symptoms of patients with COPD and enhances pulmonary and immune functions. Future studies should cover a larger and more diverse group of participants for broader validity. [ABSTRACT FROM AUTHOR]

Background: Primary graft dysfunction (PGD) is a form of acute lung injury (ALI) that occurs within 72 h after lung transplantation (LuTx) and is the most common early complication of the procedure. PGD is diagnosed and graded based on the ratio of the partial pressure of arterial oxygen to the fraction of inspired oxygen and chest X-ray results. PGD grade 3 increases recipient mortality and the chance of chronic lung allograft dysfunction (CLAD). Method: The aim of this retrospective study was to identify new PGD risk factors. The inclusion criteria were met by 59 patients, who all received transplants at the same center between 2010 and 2018. Donor data were taken from records provided by the Polish National Registry of Transplantation and analyzed in three variants: PGD 1–3 vs. PGD 0, PGD 3 vs. PGD 0 and PGD 3 vs. PGD 0–2. Results: A multiple-factor logistic regression model was used to identify decreasing recipient age; higher donor BMI and higher donor central venous pressure (CVP) for the PGD (of the 1–3 grade) risk factor. Conclusions: Longer cold ischemia time (CIT) and higher donor CVP proved to be independent risk factors of PGD 3. [ABSTRACT FROM AUTHOR]

This study aims to investigate how inert gas affects the partial pressure of alveolar and venous blood using a fast and accurate operator splitting method (OSM). Unlike previous complex methods, such as the finite element method (FEM), OSM effectively separates governing equations into smaller sub‐problems, facilitating a better understanding of inert gas transport and exchange between blood capillaries and surrounding tissue. The governing equations were discretized with a fully implicit finite difference method (FDM), which enables the use of larger time steps. The model employed partial differential equations, considering convection‐diffusion in blood and only diffusion in tissue. The study explores the impact of initial arterial pressure, breathing frequency, blood flow velocity, solubility, and diffusivity on the partial pressure of inert gas in blood and tissue. Additionally, the effects of anesthetic inert gas and oxygen on venous blood partial pressure were analyzed. Simulation results demonstrate that the high solubility and diffusivity of anesthetic inert gas lead to its prolonged presence in blood and tissue, resulting in lower partial pressure in venous blood. These findings enhance our understanding of inert gas interaction with alveolar/venous blood, with potential implications for medical diagnostics and therapies. [ABSTRACT FROM AUTHOR]

Background: Central nervous system (CNS) injury following initiation of veno-venous extracorporeal membrane oxygenation (VV-ECMO) is common. An acute decrease in partial pressure of arterial carbon dioxide (PaCO2) following VV-ECMO initiation has been suggested as an etiological factor, but the challenges of diagnosing CNS injuries has made discerning a relationship between PaCO2 and CNS injury difficult. Methods: We conducted a prospective cohort study of adult patients undergoing VV-ECMO for acute respiratory failure. Arterial blood gas measurements were obtained prior to initiation of VV-ECMO, and at every 2–4 h for the first 24 h. Neuroimaging was conducted within the first 7–14 days in patients who were suspected of having neurological injury or unable to be examined because of sedation. We collected blood biospecimens to measure brain biomarkers [neurofilament light (NF-L); glial fibrillary acidic protein (GFAP); and phosphorylated-tau 181] in the first 7 days following initiation of VV-ECMO. We assessed the relationship between both PaCO2 over the first 24 h and brain biomarkers with CNS injury using mixed methods linear regression. Finally, we explored the effects of absolute change of PaCO2 on serum levels of neurological biomarkers by separate mixed methods linear regression for each biomarker using three PaCO2 exposures hypothesized to result in CNS injury. Results: In our cohort, 12 of 59 (20%) patients had overt CNS injury identified on head computed tomography. The PaCO2 decrease with VV-ECMO initiation was steeper in patients who developed a CNS injury (− 0.32%, 95% confidence interval − 0.25 to − 0.39) compared with those without (− 0.18%, 95% confidence interval − 0.14 to − 0.21, P interaction < 0.001). The mean concentration of NF-L increased over time and was higher in those with a CNS injury (464 [739]) compared with those without (127 [257]; P = 0.001). GFAP was higher in those with a CNS injury (4278 [11,653] pg/ml) compared with those without (116 [108] pg/ml; P < 0.001). The mean NF-L, GFAP, and tau over time in patients stratified by the three thresholds of absolute change of PaCO2 showed no differences and had no significant interaction for time. Conclusions: Although rapid decreases in PaCO2 following initiation of VV-ECMO were slightly greater in patients who had CNS injuries versus those without, data overlap and absence of relationships between PaCO2 and brain biomarkers suggests other pathophysiologic variables are likely at play. [ABSTRACT FROM AUTHOR]

The list of standard abbreviations for JDS is available at adsa.org/jds-abbreviations-24. Nonstandard abbreviations are available in the Notes. Subclinical mastitis reduces milk yield and elicits undesirable changes in milk composition, but the mechanisms resulting in reduced milk production in affected mammary glands are incompletely understood. This study investigated the effects of sterile inflammation on mammary gland metabolism by assessing changes in milk and venous blood composition. Mid-lactation primiparous Holstein cows (n = 4) had udder halves randomly allocated to treatments; quarters of 1 udder half were infused with 2 billion cfu of formalin-fixed Staphylococcus aureus (FX-STAPH) and quarters of the opposite udder half were infused with saline (SAL). Blood samples were collected from the right and left subcutaneous abdominal veins in 2.6 h intervals until 40 h postchallenge and analyzed for blood gas and metabolite concentrations. Milk from FX-STAPH udder halves had significantly increased SCS by the first milking at 8 h postchallenge. By 16 h postchallenge, FX-STAPH udder halves had increased concentrations of protein and lactate and lower lactose concentrations than SAL udder halves. Milk fat concentrations, milk yields, ECM yields, and the ferric reducing antioxidant power of milk were not significantly different between SAL and FX-STAPH udder halves. Venous blood of FX-STAPH halves had marginally greater concentrations of saturated O 2 , partial pressures of O 2 , and glucose concentrations than SAL halves. Conversely, total and partial pressures of CO 2 did not differ between udder half treatments, suggesting a shift in local metabolite utilization in FX-STAPH udder halves. These results indicate that changes in milk composition resulting from mastitis are accompanied by changes in some key blood metabolite concentrations. The shift in venous blood metabolite concentrations, along with the marked increase in milk lactate, suggests that local mammary tissue or recruited immune cells, or both, alter metabolite usage in mammary tissues. Future studies are needed to quantify the uptake of key milk precursors during mastitis. [ABSTRACT FROM AUTHOR]

Objective: To discuss the link between inner ear decompression sickness and patent foramen ovale. Materials and methods: Monocentric and retrospective study on decompression sickness of the inner ear requiring hyperbaric chamber treatment, from 2014 to 2021. Results: Sixty-one patients of inner ear decompression sickness were included in this study. Twenty-four patients had vestibular injuries, 28 cochlear injuries and 9 cochleo-vestibular injuries. Compression chamber treatment was given, using an oxygen–helium mixture with oxygen partial pressure (PIO2) limited to 2.8 atmosphere absolute (ATA). All vestibular accidents completely recovered without clinical sequelae. For cochlear accident only 10 out of 37 patients (27%) recovered completely. A right–left shunt (patent foramen oval or intra-pulmonary shunt) was found in 31.1% of patients with inner ear decompression sickness (p > 0.05). Conclusion: The presence of patent foramen oval in patients with inner ear decompression was not statistically significant in our study. Understanding of the pathophysiology of decompression illness and the physiology and anatomy of the labyrinth would suggest a mechanism of supersaturation with degassing in intra-labyrinthine liquids. [ABSTRACT FROM AUTHOR]

Objective Nasal high-frequency oscillatory ventilation (nHFOV) and synchronized nasal intermittent positive pressure ventilation (sNIPPV) yield a lower partial pressure of carbon dioxide (pCO 2) after extubation than nasal continuous positive airway pressure. Our aim was to clarify which of the two was superior. Study Design We performed a crossover randomized study to evaluate pCO 2 level among 102 participants from July 2020 to June 2022. Intubated preterm and term neonates with arterial lines were randomly allocated to nHFOV–sNIPPV or sNIPPV–nHFOV sequences; their pCO 2 levels were measured after 2 hours in each mode. Subgroup analyses were performed for preterm (gestational age <37 weeks) and very preterm (gestational age <32 weeks) neonates. Results The mean gestational age (nHFOV–sNIPPV, 32.8 vs. sNIPPV–nHFOV, 33.5 weeks) and median birth weight (1,850 vs. 1,930 g) did not differ between the sequences. The mean ± standard deviation pCO 2 level after nHFOV (38.7 ± 8.8 mm Hg) was significantly higher than that after sNIPPV (36.8 ± 10.2 mm Hg; mean difference: 1.9 mm Hg; 95% confidence interval: 0.3–3.4 mm Hg; treatment effect [ p = 0.007] but no sequence [ p = 0.92], period [ p = 0.53], or carryover [ p = 0.94] effects). However, the difference in pCO 2 level between the sequences was not statistically significant in the subgroup analyses of preterm and very preterm neonates. Conclusion After neonatal extubation, the sNIPPV mode was associated with a lower pCO 2 level than the nHFOV mode with no significant difference in preterm and very preterm neonates. Key Points Full noninvasive ventilation support is suggested in neonatal ventilation. pCO 2 level in sNIPPV was lower than in nHFOV. No differences in pCO 2 levels were observed in either preterm or very preterm neonates. [ABSTRACT FROM AUTHOR]

To investigate the effects of clinical modalities and configurations on oxygenator pressure loss (ΔP), oxygen transfer ability and thrombosis risk and to find out the optimal oxygenator configuration. Modified partial pressure of oxygen (PO2) and a newly proposed thrombosis risk model (constructed from platelets, coagulation factors, hemostatic proteins, and blood stagnation) were used for this study. Oxygen transport and thrombosis risk assessment experiments were used for validation. Both simulation and experimental results indicate that when oxygenator operates at low flow rates with low-pressure loss and high PO2, they produced thrombin concentrations and increased thrombosis risk. For the same membrane fiber region, variations in the oxygenator external structure did not affect PO2 and thrombin production. For the ΔP and thrombosis risk, square oxygenators > round oxygenators, single-inlet oxygenators > multiple-inlet oxygenators, and lower inlet and lower outlet oxygenators > center inlet and center outlet oxygenators. The oxygenator high thrombosis risk region was identified as the blood-to-blood/border impingement region. A study of 81 oxygenator inlet and outlet combinations found that the inlet and outlet locations had little effect on ΔP and PO2. Oxygenator thrombosis risk was the lowest when using a center inlet and an upper/lower outlet configuration. The accuracy of the thrombosis risk model was validated. The oxygenator operation mode had a significant effect on ΔP, PO2, and thrombosis risk. Changes in the oxygenator external configuration had a significant impact on thrombosis. The lowest thrombosis risk was found in the center inlet and upper/lower outlet round oxygenator configuration. [ABSTRACT FROM AUTHOR]

In 2015, the Indian Ocean exhibits an exceptionally weakened CO2 uptake, highlighting strong interannual variability of ocean carbon sink. By utilizing multiple ocean CO2 partial pressure (pCO2) data and a state‐of‐the‐art ocean biogeochemical model, we show that the 2015 ocean CO2 anomaly is characterized by a basin‐wide amplification of ocean pCO2, differing from ocean pCO2 responses to other Indian Ocean Dipole events (e.g., 1997 and 2019). The distinct ocean pCO2 anomaly is attributed to an amplified warming and an unprecedented weakening Indonesian Throughflow under the influence of co‐occurrence of positive IOD and extreme El Niño in 2015. The amplified warming drives higher ocean pCO2 in the western and central Indian Ocean, while the ITF transports anomalously high ocean pCO2 water from the Pacific Ocean to the southeastern Indian Ocean. This newly identified ocean carbon response provides deeper insights into the Indian Ocean carbon interannual variability. [ABSTRACT FROM AUTHOR]

Sr 0.99 La 0.01 TiO 3 (SLT10) colossal permittivity (CP) ceramic materials were synthesized using solid phase method and secondary heat treated using mixed oxidant 35%Bi 2 O 3 –10%Al 2 O 3 –20%MgO–25%CuO–10%SiO 2 oxidant. The heat treatment atmospheres were chosen as O 2 , air, and Ar to correspond to different oxygen partial pressures. The dielectric properties of the Sr 0.99 La 0.01 TiO 3 -Percolated (SLT10-P) ceramics were investigated, and the contribution of the oxidant to the resistivity enhancement was verified by complex impedance spectroscopy and DC resistivity tests. Excellent dielectric properties were obtained for SLT10-P Air ceramic sample (16543 for dielectric permittivity and 0.016 for loss tangent), and the resistivity was increased from 2.13 × 108 Ω cm (SLT10) to 1.23 × 1011 Ω cm (SLT10-P Air). The resistance degradation mechanism of SLT10-P ceramics and oxygen vacancy migration in the process of resistance degradation were studied by using resistance monitoring device and thermally stimulated depolarization currents (TSDC) test. The introduction of oxidant optimizes the temperature stability and resistivity of SLT10 ceramics, but it will lead to the decrease of dielectric permittivity. The atmosphere of heat treatment changed the concentration of oxygen vacancy in ceramics. When SLT10-P O 2 was treated in O 2 atmosphere, the concentration of oxygen vacancy in ceramics decreased, which led to the decrease of dielectric permittivity and the increase of grain boundary resistance. For SLT10-P Ar ceramic, more oxygen vacancies and free electrons are induced by low oxygen partial pressure heat treatment, which enhances the dipole effect of electron pinning defects and leads to colossal dielectric permittivity, but high concentration of oxygen vacancies will affect the resistance decline. In SLT10-P Air ceramic, the coexistence of colossal permittivity and low loss tangent and high resistance is realized. [ABSTRACT FROM AUTHOR]

In this work, a series of multiple lanthanide and tungsten co-doped fluorite structured (Bi 2 O 3) 0.95- x (Ho 0.4 Er 0.4 Tm 0.4 Yb 0.4 Lu 0.4 O 3) x (WO 3) 0.05 (x = 0.1, 0.2, 0.3, 0.4) and (Bi 2 O 3) 0.26 (Ho 0.5 Er 0.5 Tm 0.5 Yb 0.5 O 3) 0.48 (WO 3) 0.26 materials were prepared by traditional solid-state reaction method. The phases, stabilities, and electrical properties of these materials were thoroughly studied. The results revealed that under high oxygen partial pressure, CO 2 , or inert atmospheres, all these samples had excellent long term thermal stability and chemical stability, and the samples of (Bi 2 O 3) 0.95- x (Ho 0.4 Er 0.4 Tm 0.4 Yb 0.4 Lu 0.4 O 3) x (WO 3) 0.05 (x = 0.1, 0.2, 0.3, 0.4) with low or mediate configuration entropies showed pure and high oxide ion conductivities, e.g. ∼2.6 × 10−2 S/cm at 600 °C for the sample x = 0.2. Whereas, for the (Bi 2 O 3) 0.26 (Ho 0.5 Er 0.5 Tm 0.5 Yb 0.5 O 3) 0.48 (WO 3) 0.26 sample with high configuration entropy, pure ionic conduction occurred only within a narrow temperature range (700−750 °C) under the N 2 atmosphere. Under strong reducing condition, only the high-entropy sample (Bi 2 O 3) 0.26 (Ho 0.5 Er 0.5 Tm 0.5 Yb 0.5 O 3) 0.48 (WO 3) 0.26 showed high phase and chemical stabilities, but would introduce strong electronic conduction rise from the reduction of the high content W6+. While for (Bi 2 O 3) 0.95- x (Ho 0.4 Er 0.4 Tm 0.4 Yb 0.4 Lu 0.4 O 3) x (WO 3) 0.05 with low or mediate configuration, phase decompositions with impurities of Bi metal and HoH 2 were observed under strong reducing atmosphere, accompany with obviously decreased conductivities. Therefore, we provided here a comprehensive understanding for the multiple components doped Bi 2 O 3 -based materials with configuration entropy from low to high on their phases, stabilities, and electrical properties, and suggested a new strategy for designing and stabilizing bismuth-oxide-based materials. [ABSTRACT FROM AUTHOR]

BACKGROUND: Noninvasive ventilation (NIV) is a widely used and well-established treatment modality for respiratory failure. In patients with increased respiratory work of breathing, accessory muscles are commonly activated along with the diaphragm. Whereas diaphragm ultrasound has been utilized to assess outcomes of mechanical ventilation, the data on intercostal muscle ultrasound remain limited. We aimed to investigate the association between intercostal muscle thickening fraction (TF) and NIV failure in critical care patients with hypercapnic respiratory failure. METHODS: Critical care subjects receiving NIV for hypercapnic respiratory failure were enrolled in the study. The intercostal muscle TF was measured on admission day (day 0) and the following day (day 1). NIV failure was defined as the need for invasive mechanical ventilation or death during NIV therapy. RESULTS: A total of 158 subjects were enrolled, and 30 experienced NIV failure. Age, sex, and body mass index (BMI) were similar in the NIV success and failure groups. Acute Physiology And Chronic Health Evaluation II (APACHE II) and the Sequential Organ Failure Assessment (SOFA) scores were higher in the NIV failure group. In terms of causes of respiratory failure, the COPD exacerbation rate was higher in the NIV success group. TF was higher in the NIV failure group on both day 0 and day 1. The increased TF on the ICU admission day, with a cutoff value of 12%, was associated with NIV failure after adjusting for age, sex, BMI, APACHE II, and SOFA. Persistence of a higher TF value on both day 0 and day 1 was also associated with NIV failure risk. CONCLUSIONS: There was a positive relation between intercostal muscle TF measured by ultrasound and NIV failure, even after adjusting for APACHE II and SOFA scores. [ABSTRACT FROM AUTHOR]

Copyright of Journal of China Medical University is the property of Journal of China Medical University Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Utilizing an 11‐year (2011–2021) data set, we report surface‐ocean pCO2 in Baffin Bay during the open‐water season (June–October) to establish a baseline understanding of surface seawater carbon dynamics in this region. We found pCO2 was strongly undersaturated (70–130 μatm below saturation, depending on year), albeit with substantial regional variability. Though temperature was found to be a generally strong control of pCO2, sea‐ice dynamics and other non‐thermal drivers controlled pCO2 at certain times and in certain regions. The Baffin Island Current region (western Baffin Bay) experienced relatively high pCO2 during instances of high sea‐ice cover, usually in early spring. Average pCO2 was comparatively lower in the West Greenland Current region (eastern Baffin Bay) which is ice‐free substantially longer (by 3–4 months) and where temperature acted as the dominant control to pCO2. With respect to temporal variations, June had the lowest pCO2 of the open‐water season, coinciding with active sea‐ice melt. Surface‐ocean pCO2 then increased month‐to‐month through July and August due to warming and decreased meltwater dilution, increasing again into September before stabilizing into October. Generally, non‐thermal controls acted to decrease pCO2 during mid‐summer (possibly primary production, sea‐ice melt, and circulation), but acted to increase pCO2 during early fall (vertical mixing). Despite spatial and temporal variation over the open‐water season, persistent undersaturation suggests that Baffin Bay is a potentially strong CO2 sink, even in comparison to other uptake regions across the western Arctic. Plain Language Summary: When the surface‐ocean partial pressure of CO2 (pCO2) is less than the atmospheric pCO2, the ocean absorbs CO2 from the atmosphere. Surface‐ocean pCO2 varies greatly in space and time and has been poorly documented in difficult‐to‐access Arctic regions. By measuring surface‐ocean pCO2 over an eleven ‐year period, we have shown for the first time that the Baffin Bay region is consistently undersaturated in CO2 over the open‐water season (June–October). The variations in surface‐ocean pCO2 between regions across the bay are strongly related to the differences in sea ice and temperature, with lower pCO2 in eastern than in western Baffin Bay. As a whole, the surface of Baffin Bay is most undersaturated in June due to active sea‐ice melt. Surface‐ocean pCO2 increases over July and August, before stabilizing at slightly higher values in September and October, before freeze‐up. Based on these results, Baffin Bay appears to be a large atmospheric CO2 sink, even in comparison to other uptake regions of the western Arctic. Key Points: Baffin Bay surface waters are strongly undersaturated in pCO2 relative to atmospheric values during the open‐water seasonOverall, pCO2 in Baffin Bay was lowest in June, increasing from July to September, before stabilizing in OctoberTemperature and sea‐ice dynamics are important controls of pCO2 in Baffin Bay [ABSTRACT FROM AUTHOR]

Copyright of Science & Technology of Food Industry is the property of Science & Technology of Food Industry Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Aims: Both hypercapnia and hypocapnia are common in patients with acute heart failure (AHF), but the association between partial pressure of arterial carbon dioxide (PaCO2) and AHF prognosis remains unclear. The objective of this study was to investigate the connection between PaCO2 within 24 h after admission to the intensive care unit (ICU) and mortality during hospitalization and at 1 year in AHF patients. Methods and results: AHF patients were enrolled from the Medical Information Mart for Intensive Care IV database. The patients were divided into three groups by PaCO2 values of <35, 35–45, and >45 mmHg. The primary outcome was to investigate the connection between PaCO2 and in‐hospital mortality and 1 year mortality in AHF patients. The secondary outcome was to assess the prediction value of PaCO2 in predicting in‐hospital mortality and 1 year mortality in AHF patients. A total of 2374 patients were included in this study, including 457 patients in the PaCO2 < 35 mmHg group, 1072 patients in the PaCO2 = 35–45 mmHg group, and 845 patients in the PaCO2 > 45 mmHg group. The in‐hospital mortality was 19.5%, and the 1 year mortality was 23.9% in the PaCO2 < 35 mmHg group. Multivariate logistic regression analysis showed that the PaCO2 < 35 mmHg group was associated with an increased risk of in‐hospital mortality [hazard ratio (HR) 1.398, 95% confidence interval (CI) 1.039–1.882, P = 0.027] and 1 year mortality (HR 1.327, 95% CI 1.020–1.728, P = 0.035) than the PaCO2 = 35–45 mmHg group. The PaCO2 > 45 mmHg group was associated with an increased risk of in‐hospital mortality (HR 1.387, 95% CI 1.050–1.832, P = 0.021); the 1 year mortality showed no significant difference (HR 1.286, 95% CI 0.995–1.662, P = 0.055) compared with the PaCO2 = 35–45 mmHg group. The Kaplan–Meier survival curves showed that the PaCO2 < 35 mmHg group had a significantly lower 1 year survival rate. The area under the receiver operating characteristic curve for predicting in‐hospital mortality was 0.591 (95% CI 0.526–0.656), and the 1 year mortality was 0.566 (95% CI 0.505–0.627) in the PaCO2 < 35 mmHg group. Conclusions: In AHF patients, hypocapnia within 24 h after admission to the ICU was associated with increased in‐hospital mortality and 1 year mortality. However, the increase in 1 year mortality may be influenced by hospitalization mortality. Hypercapnia was associated with increased in‐hospital mortality. [ABSTRACT FROM AUTHOR]

CO2 geological utilization and storage (CGUS) is a key technology to achieve carbon neutrality goals. To apply CGUS on a larger scale, the issue of steel corrosion during the process must be addressed to mitigate technological risks. This paper provides an overview of CO2-induced steel corrosion mechanisms and identifies factors that influence corrosion. The impact of CO2 partial pressure, temperature, salinity, pH, impurities, and fluid flow on steel corrosion behavior are also discussed. With the presence of water, the corrosive effect of supercritical CO2 on steel is stronger than that of dissolved CO2 or gaseous CO2. As the temperature increases, the corrosion rate of steel first increases and then decreases. Increasing salinity and decreasing pH lead to an accelerated corrosion rate of steel. Corrosion inhibitors, coatings, and corrosion-resistant alloys are recommended protective measures against CO2-induced corrosion. Compared with coatings, corrosion inhibitors and corrosion-resistant alloys are more commonly used in CGUS projects. Future research directions include further exploration of the mechanisms underlying CO2-induced steel corrosion, clarifying the coupled effects of various environmental factors, and developing corrosion protection technologies under high-pressure and high-concentration CO2 conditions. [ABSTRACT FROM AUTHOR]

The high‐temperature corrosion behavior of Ni–xFe–5Cr alloys (x = 0, 10, or 30 wt.%) was investigated in air containing alkali salt vapor at 570°C to clarify the effect of Fe on the corrosion resistance. Fe addition to Ni–5Cr was found to improve the corrosion resistance under the present conditions. In the case of Ni–5Cr, NiCl2 was formed beneath the NiO scale during the initial stage of corrosion, and it grew thicker over time and then evaporated. The formation and evaporation of NiCl2 resulted in a porous scale that underwent spallation resulting in mass loss. In the Fe‐containing alloys, (Fe, Ni, Cr)3O4 spinel and Fe3O4 decreased the partial pressures of oxygen and chlorine and thus prevented the generation of NiO and NiCl2, leading to superior corrosion resistance compared with Ni–5Cr. [ABSTRACT FROM AUTHOR]

The corrosion behavior of 304 stainless steel in wet CO2 gas with or without CO and CO plus 400 ppmv SO2 was investigated in this study. Corrosion kinetics was studied by thermogravimetric analysis at 710°C for 100 h under three gas conditions. After isothermal exposure, the corroded coupons were characterized in detail by X‐ray diffraction, scanning electron microscopy, an electron probe microanalyzer, and transmission electron microscopy. CO addition to wet CO2 resulted in lower oxygen partial pressure and lower oxide growth kinetics. It also suppressed iron‐rich oxide nodule formation, as compared to the wet CO2 gas environment. A Cr‐depletion zone was observed underneath the oxide scale in the substrate, but no obvious internal carburization was observed in all three gas environments. A thin, protective oxide scale consisting of an outer layer of a Cr‐rich spinel and an inner Cr‐rich chromia layer was developed in CO‐containing gas conditions, with or without SO2. The effect of CO on oxidation and scale formation is discussed in comparison with that in wet CO2 conditions. [ABSTRACT FROM AUTHOR]

Methane (CH4) is a primarily biogenic greenhouse gas. As such, it represents an essential biosignature to search for life on exoplanets. Atmospheric CH4 abundance on Earth-like inhabited exoplanets is likely controlled by marine biogenic production and atmospheric photochemical consumption. Such interactions have been previously examined for the case of the early Earth where primitive marine ecosystems supplied CH4 to the atmosphere, showing that the atmospheric CH4 response to biogenic CH4 flux variations is nonlinear, a critical property when assessing CH4 reliability as a biosignature. However, the contributions of atmospheric photochemistry, metabolic reactions, or solar irradiance to this nonlinear response are not well understood. Using an atmospheric photochemical model and a marine microbial ecosystem model, we show that the production of hydroxyl radicals from water vapor photodissociation is a critical factor controlling the atmospheric CH4 abundance. Consequently, atmospheric CH4 partial pressure (p CH4) on inhabited Earth-like exoplanets orbiting Sun-like stars (F-, G-, and K-type stars) would be controlled primarily by stellar irradiance. Specifically, irradiance at wavelengths of approximately 200–210 nm is a major controlling factor for atmospheric p CH4 when the carbon dioxide partial pressure is sufficiently high to absorb most stellar irradiance at 170–200 nm. Finally, we also demonstrated that inhabited exoplanets orbiting near the outer edge of K-type stars' habitable zones are better suited for atmospheric p CH4 buildup. Such properties will provide valuable support for future detection of life signatures. [ABSTRACT FROM AUTHOR]

Dry reforming of methane (DRM) reaction is advantageous in producing syngas with a low H2/CO, relevant to many industries. Effect of contact time on catalytic activity and carbon deposition is studied for DRM using Ni−Al catalysts, along with the effect of metal loading, reaction temperature, and reactant partial pressure (CO2/CH4). Maximum CH4 conversion (58 %) and CO2 (59 %) were achieved at a higher contact time of 4.009 kg‐cat. h/kgCH4. A maximum of 46 % CH4 conversion was achieved at 1023 K with a contact time of 0.134 kg‐cat. h/kgCH4. Higher CH4 and CO2 conversion were achieved with an excellent H2 and CO yield due to the RWGS reaction with increased metal (Ni) loading (10–30 wt. %). When the reactant partial pressure (CO2) changed from 0.1–0.3, the CH4 conversion increased whereas CO2 conversion decreased. FESEM images revealed the formation of whisker‐like carbon fibers for all loadings. For the best syngas output and stability in a Ni‐based catalyst, a combination of a basic support (alumina) at a higher contact time (~4.009 kg‐cat. h/kgCH4) and a CO2/CH4 ratio of 1–1.5 at a moderate temperature of 873 K may provide best CO2 adsorption with minimal coking. [ABSTRACT FROM AUTHOR]

A comprehensive process model for 4H‐SiC oxidation is created and calibrated against a very large collection of experimental data. The model reproduces measured oxide thickness for Si‐face, C‐face, and a‐face SiC wafers, in the temperature range 950–1500 °C, in the pressure range 0.25–4.0 atm, in the thickness range 3–1600 nm, and for SiC doping ranging between 1019 cm−3 n‐type and 1019 cm−3 p‐type. The model is based on the Massoud model: Oxidation is driven by oxidants (O2, H2O) which are present in the gas phase, diffuse through the oxide, and form SiO2 at the oxide–SiC interface. For thin oxides, the interface reaction rate includes empirical correction terms which add to the oxidation rate, and which asymptotically approach zero with increasing oxide thickness. For dry oxidation, a remarkable dependence on the O2 partial pressure is discovered: For thick oxides, the oxidation rate scales linearly with the pressure, but the correction term for thin oxides scales with the square root of the pressure. This suggests that the atomistic processes responsible for the fast initial growth of oxides involve the splitting of O2 molecules into two O atoms. [ABSTRACT FROM AUTHOR]

The ZrN coatings were prepared using multi-arc ion plating (MAIP) under different N 2 partial pressures ranging from 10 % to 80 %. A comprehensive analysis of the microstructure, electrochemical behavior, and tribocorrosion properties of these coatings showed a gradual deposition rate decrease with rising N 2 partial pressure. Analysis using GIXRD revealed higher N 2 pressure led to a shift in crystal orientation from (111) to (200), initially increasing corrosion resistance but later declining. At 70 % N 2 pressure, the ZrN coating exhibited the lowest values of capacitance C po (8.89 μF cm−2) and double-layer capacitance C dl (1.14 × 10−7 F cm−2), with the highest values for the two-time constants τ recorded as 0.274 s and 5.749 s. The tribocorrosion behavior correlated closely with the corrosion performance, with the ZrN-70 % coating demonstrating superior tribocorrosion resistance and a minimal wear rate of 4.25 × 10−5 mm3/Nm. While the ZrN-80 % coating exhibited the lowest wear rate of 2.67 × 10−5 mm3/Nm, but was more susceptible to friction and corrosion synergy, causing localized failure. The outcomes reveal crystal texture significantly affected on the electrochemical and tribocorrosion characteristics of the coatings, primarily attributed to the robust passivation tendency and stability of the passivation film associated with the (200) crystal orientation. The dominant wear mechanism identified involves the interplay of adhesive, abrasive, and corrosion-erosion wear processes. Based on these results, ZrN coatings prepared using MAIP are expected to emerge as candidate materials for critical friction components in marine equipment or other corrosion-erosion environments. [ABSTRACT FROM AUTHOR]

Under simulated conditions typical of a high-temperature, high-pressure (HTHP) oil and gas reservoir in the South China Sea, dynamic corrosion evaluation experiments were performed on a three-layer screen structure and three types of sand retaining media. The results showed significant variations in corrosion morphology and rates among different screen components and materials. Corrosion products on the base pipe accumulated as cubic crystals, while the protective shroud showed surface needle-like corrosion products. Sand retaining media exhibited "coiled wire" corrosion products with cubic accumulations along seam edges. The 316L media showed a high corrosion risk, especially at temperatures between 140–150 °C. As CO2 partial pressure increased, corrosion rates generally rose. A new predictive method was developed to assess and compare the corrosion resistance and life of screens, achieving a compliance rate of over 90%. This method supports evaluating the corrosion life of screens in HTHP environments. For a typical well in the South China Sea gas field with 4% CO2, there is a high risk of screen corrosion. The screen media was identified as a failure site with a minimum corrosion life of about 5 years, while the protective shroud's life was estimated at 11–12 years. [ABSTRACT FROM AUTHOR]

Analyzing PEM electrolyzer polarization curves via voltage breakdown analysis involves decomposing contributions from underlying processes, typically based on the assumption of reaction kinetics that may be expressed by means of the Tafel equation. When extrapolating the corresponding straight line to high current densities, there is a discrepancy between the measurement and model, which is often attributed to mass transport resistance. In addition to the qualitative description of this mass transport resistance, a consistent quantification is difficult to obtain from the measurement results. Accordingly, the approach to the breakdown analysis of the polarization curves is strongly based on assumptions that evade experimental verification. In this study, an alternative statistical method is introduced that permits the falsifiability of the standard approach. By means of experiments at different hydrogen partial pressures and a subsequent data fit, it is possible to extract the kinetic behavior without prior specification. The results indicate that behavior corresponding to the Tafel equation cannot be proven wrong. In addition, transport coefficients can be evaluated that fall between those of membranes and porous transport layers, indicating that the catalyst layer predominantly contributes to the mass transport resistance. [ABSTRACT FROM AUTHOR]