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Abstract Background Oxygen therapy is routinely administered to mechanically ventilated patients. However, there remains uncertainty about the optimal oxygen titration target in patients with the acute respiratory distress syndrome (ARDS). Methods Prospectively identified adult patients meeting the Berlin definition of ARDS between 1st January 2014 and 13th December 2016 were analyzed. Oxygen exposure variables were collected at 6-hourly intervals. The primary exposure was the average time-weighted partial pressure of arterial oxygen (PaO2) calculated over a maximum of 7 days from meeting ARDS criteria. The primary outcome was ICU mortality. Univariable and multivariable logistic regression analyses were performed to assess the impact of exposure variables on clinical outcomes. Results are presented as odds ratio [95% confidence interval]. Results 202 patients were included in the final analysis. Overall ICU mortality was 31%. The average time-weighted PaO2 during the first 7 days of ARDS was similar between non-survivors and survivors (11.3 kPa [10.2, 12.5] (84.8 mmHg [76.5, 93.8]) vs. 11.9 kPa [10.9, 12.6] (89.3 mmHg [81.8, 94.5]); p = 0.08). In univariable and multivariable analysis, average time-weighted PaO2 demonstrated a U-shaped relationship with ICU mortality. There was a similar relationship identified with hospital mortality. Conclusions In patients with ARDS, the predicted probability of both ICU and hospital mortality was lowest when the average time-weighted PaO2 was between 12.5 and 14 kPa (93.8–105.0 mmHg), suggesting this is a reasonable oxygenation target for clinicians to aim for.

We report here a comparative study of the effects of La-substituted Ca on (Bi, Pb):2212 and (Bi, Pb):2223 superconductors with various La content (0.00 ≤ x ≤ 0.30). Regardless of the effects of La, it is evident that the superconducting volume fraction, excess of oxygen, critical concentration for quenching superconductivity, Vickers hardness, anisotropy, interlayer coupling, critical magnetic fields, and critical current were higher for the 2212 series than the 2223 series. In contrast, orthorhombic distortion, c-parameter, crystallite diameter, doping distance, distance between two Cu atoms, hole carrier/Cu ion ratio, melting temperature Tm, critical temperature Tc, onset of diamagnetic TcM, surface energy, elastic component, resistance pressure, and c-axis coherence length were higher for the 2223 series than the 2212 series. An inverse linear relationship between Tm and Tc was estimated for both series, and for room-temperature (RT) bismuth–strontium–calcium–copper–oxide (BSCCO) superconductors, the required Tm values should be 1048.03°C for the 2223 series and 784.48°C for the 2212 series. Surprisingly, the difference in temperature between zero resistivity and diamagnetic onset |TcM − TcR| for La = 0.30 samples is 30 K. In the critical field region (CFR), the exponents of order parameters (OPD) are two-dimensional (2D), but their values were higher for the 2212 series than the 2223 series. Further, they became three-dimensional (3D) as La increased to 0.30 due to the reduced effective length in highly substituted samples. Our results were discussed with the help of the differences in the physical parameters between the considered series. These findings revealed that the 2212 series is more suitable for applications that need higher hardness and critical fields and currents. In contrast, the 2223 series is more suitable for research for higher Tc and altering plastic deformation. To our knowledge, the present systematic investigation has not been reported elsewhere, which highlights the present work. [ABSTRACT FROM AUTHOR]

The high‐performance amorphous In‐Ga‐Sn‐O (a‐IGTO) thin‐film transistors (TFTs) was fabricated with plasma‐enhanced atomic layer deposition (PEALD)‐derived Al2O3 high‐k gate dielectric at a maximum processing temperature of 150 °C. During the deposition of Al2O3 dielectric on a‐IGTO films, the hydrogen (H) and excess oxygen (Oi) defects from the Al2O3 act significant role on TFTs operation. The amounts of H and Oi can be controlled by adjusting oxygen plasma density in radio‐frequency (rf) of PEALD. The optimized a‐IGTO TFT exhibit high‐performance electrical properties with field‐effect mobility (μFE) of 58.8 cm2/Vs, subthreshold gate swing (SS) of 0.12 V/decade, threshold voltage (VTH) of 0.5 V. [ABSTRACT FROM AUTHOR]

Eliminating Carbon Monoxide (CO) by oxidation using efficient and affordable catalysts holds significant potential for addressing various industrial and environmental challenges. In this study, we investigate the low-temperature oxidation of CO for a broad range of catalysts, while we investigate the effect of moisture and the presence of oxygen for the best -performing catalyst. Ceria oxide (CeO 2) and copper oxide (CuO) catalysts supported on niobium oxide (Nb 2 O 5) were synthesized at various loadings, characterized, and tested for the oxidation of carbon monoxide. Several different techniques were used including, X-ray diffraction (XRD), Fourier Transform Infrared (FT-IR), Transmission electron microscopy (TEM), N 2 Adsorption-desorption (BET), and Raman spectroscopy, to investigate the physiochemical properties of the prepared catalysts and their effect on the desired catalytic activity. XRD findings indicated that there were synergistic interactions between copper oxide (CuO) and CeO 2 BET results revealed that synthesized catalysts have high surface area and uniform pore size distribution over supports. It was found that a 10% CuO-CeO 2 supported on Nb 2 O 5 shows a significantly improved performance among all the catalysts with full conversion observed at temperatures as low as 150℃. This catalyst endures high stability over a long reaction time (stability tests are performed up to 12 hours). Kinetics parameters were also determined where the fitted activation energy (23.1 kJ mol-1) follows the CO activity trends. The second best-performing catalyst CuO-CeO 2 demonstrated remarkable versatility in adapting to a wide range of space velocities, ranging from 14,400 to 25,200 cm3 g-1 h-1. The effect of excess oxygen (λ) in the feed was also determined and discussed in detail. DFT computations provided the energy profile for the surface oxidation of CO. Results from this work pave the way to formulate low-temperature catalytic operations for the oxidation of CO at practical conditions, i.e., to treat the effluents from internal combustion engines. [Display omitted] • The study investigated catalytic CO oxidation under practical combustion conditions using non-noble materials. • CuO addition enhances the catalytic capacity of CeO 2 /Nb 2 O 5 toward CO oxidation. • The best performing catalyst endures high stability over a relatively long reaction time. • Utilizing excess oxygen in the feed correlates positively with CO oxidative conversion. • Combined DRIFTS measurements and DFT computations explore the operating oxidation mechanism. [ABSTRACT FROM AUTHOR]

Background: Oxygen therapy is routinely administered to mechanically ventilated patients. However, there remains uncertainty about the optimal oxygen titration target in patients with the acute respiratory distress syndrome (ARDS).Methods: Prospectively identified adult patients meeting the Berlin definition of ARDS between 1st January 2014 and 13th December 2016 were analyzed. Oxygen exposure variables were collected at 6-hourly intervals. The primary exposure was the average time-weighted partial pressure of arterial oxygen (PaO2) calculated over a maximum of 7 days from meeting ARDS criteria. The primary outcome was ICU mortality. Univariable and multivariable logistic regression analyses were performed to assess the impact of exposure variables on clinical outcomes. Results are presented as odds ratio [95% confidence interval].Results: 202 patients were included in the final analysis. Overall ICU mortality was 31%. The average time-weighted PaO2 during the first 7 days of ARDS was similar between non-survivors and survivors (11.3 kPa [10.2, 12.5] (84.8 mmHg [76.5, 93.8]) vs. 11.9 kPa [10.9, 12.6] (89.3 mmHg [81.8, 94.5]); p = 0.08). In univariable and multivariable analysis, average time-weighted PaO2 demonstrated a U-shaped relationship with ICU mortality. There was a similar relationship identified with hospital mortality.Conclusions: In patients with ARDS, the predicted probability of both ICU and hospital mortality was lowest when the average time-weighted PaO2 was between 12.5 and 14 kPa (93.8-105.0 mmHg), suggesting this is a reasonable oxygenation target for clinicians to aim for. [ABSTRACT FROM AUTHOR]

Progressive optimization of the surface passivation of Si solar cells requires access to the elemental composition and chemical bonding characteristics of ultrathin layers and buried interfaces on textured or structured surfaces. The passivation of the rear side of passivated emitter and rear solar cells, for instance, can be realized through AlOx/SiNx stacks, which are known to provide an additional field effect passivation on top of the chemical surface passivation. Herein, transmission electron microscopy is used at locally prepared cross‐sections of such stacks. Electron energy loss spectroscopy is used to extract depth‐resolved information of elemental composition and chemical bonding at nanometer scale. With this, the interfacial excess O fraction, which is crucial for the field effect passivation, is successfully determined for the first time for AlOx passivation layer systems on industrially produced Si solar cells. [ABSTRACT FROM AUTHOR]

Recently, a new production process of various metals and alloys from their oxides and ores by Cold Hydrogen Plasma (CHP) has been introduced. CHP is produced by using a microwave oven, using less power than the microwave ovens used domestically for cooking food. CHP is very efficient in producing metals and alloys from their oxides because of excited species. These excited species decrease the thermodynamic and kinetic barriers of reduction, making the reduction easier and faster. In the current investigation, nickel has been produced from nickel oxide (NiO) pellets of ~ 2.5 gm to ~ 7.5 gm. The hydrogen flow rate ranges from 70 ml/s to 150 ml/s, and power varies from 600 to 750 W. The time taken for reduction changed between 300 to 1200 s. CHP reduces very fast due to the active oxygen present in it. This faster production of nickel from pellets upto ~ 7.5 gm at such low power opens up the possibilities of upscaling the reduction of NiO by CHP. [ABSTRACT FROM AUTHOR]

• Numerical model is developed to investigate oxy-coal combustion in novel swirl burner. • Flame properties and flame type change significantly at different oxygen excess values. • Carbon monoxide decreases and nitrogen oxides increase with increase of oxygen excess. • Burner is able for stable work with similar flame shape in both combustion modes. • Carbon monoxide and nitrogen oxides are lower during oxy-fuel than air combustion. Oxy-fuel combustion is the most promising carbon capture and storage technology, which eliminates carbon dioxide emissions into the atmosphere and also decreases nitrogen oxides emissions thereby lowering global warming potential. In order to implement oxy-fuel combustion technology in full scale power plants, its costs, mainly connected with the amount of pure oxygen produced, must be lowered. The main hypothesis is that it is possible to maintain similar velocity and heat transfer distribution while maintaining stable and efficient burner operation during both combustion technologies modifying burner aerodynamics. Excess oxygen is chosen as a representative parameter of burner's performance and investigation is carried out for four different oxy-fuel burner oxygen excess ratios (λ: 0.8, 0.98, 1.07, and 1.24) together with reference air combustion case. This study suggests a workflow, based on semi-industrial experimental investigations and computational fluid dynamics model composed of advanced sub-models for different combustion phases for development of real scale dual-mode coal swirl burners able for efficient operation during both combustion regimes. The results show that the temperature in near-burner zone and nitrogen oxides emissions increase, while carbon monoxide emissions decrease with the increase of burner oxygen excess ratio, and stable combustion with similar velocity and temperature distributions for both combustion modes is achieved for oxygen excess ratio of 1.07, with decrease in nitrogen oxides and carbon monoxide emissions during oxy-fuel combustion. The performed study demonstrates that it is possible to choose the appropriate burner settings regarding nitrogen oxides and carbon monoxide emissions and burner's ability to operate stably in both air and oxy-fuel combustion modes. [ABSTRACT FROM AUTHOR]

Abstract Bulk CuAlO 2 compound has been widely studied as a p-type metal oxide semiconductor material due to the simplicity in its synthesis and use of inexpensive raw materials. The Fe doping in CuAlO 2 has been demonstrated to enhance the electrical conductivity. An in-depth analysis of the effect of Fe doping in CuAlO 2 on the carrier concentration improvement was revealed. Delafossite CuAl 1−x Fe x O 2 powders with x = 0.00, 0.05, 0.10, 0.15, 0.20 and 0.30 were synthesized by a solid-state reaction method. The X-ray photoelectron spectroscopy (XPS) and X-ray absorption spectroscopy (XAS) studies were used to measure the atomic-ion concentrations and the oxidation state of each element. The variations of carrier concentration corresponded with a ratio of Cu2+/Cu1+ in CuAlO 2. We found that the increase of Cu2+/Cu1+ was caused by double effects through divalent metal ions (Fe2+) doping and excess oxygen (O 2−δ) in CuAlO 2. The maximum carrier concentration of 8.09 × 1017 cm−3 was obtained for the CuAlO 2 sample at Fe content of 10 at.%. Highlights • XPS and XAS are used to identify CuAl 1−x Fe x O 2 for understanding in-depth mechanism. • Fe doping improves interstitial O 2 and surface oxygen adsorption capability of CuAlO 2. • The variations of carrier concentration caused by double effects, Fe2+ and O 2+δ [ABSTRACT FROM AUTHOR]

Mixed ionic and electronic conducting K2NiF4-type oxide, Nd2Ni1-xCuxO4+δ (x=0~1) powders were synthesized by solid state reaction technique and solid oxide fuel cells consisting of a Nd2Ni1-xCuxO4+δ cathode, a Ni-YSZ anode and ScSZ as an electrolyte were fabricated. The effect of copper substitution for nickel on the electrical and electrochemical properties was examined. Small amount of copper doping (x=0.2) resulted in the increased electrical conductivity and decreased polarization resistance. It appears that this phenomenon was associated with the high mean valence of nickel and copper and the resulting excess oxygen (δ). It was found that power densities of the cell with the Nd2Ni1-xCuxO4+δ (x=0.1 and 0.2) cathode were higher than that of the cell with the Nd2NiO4+δ cathode.

The catalytic performance of a series of La-Fe/AC catalysts was studied for the selective catalytic reduction (SCR) of NO by CO. With the increase in La content, the Fe2+/Fe3+ ratio and amount of surface oxygen vacancies (SOV) in the catalysts increased; thus the catalytic activity improved. Incorporating the promoters to La3-Fe1/active carbon (AC) catalyst could affect the catalyst activity by changing the electronic structure. The increase in Fe2+/Fe3+ ratio after the promoter addition is possibly due to the extra synergistic interaction of M (Mn and Ce) and Fe through the redox equilibrium of M3+ + Fe3+ ↔ M4+ + Fe2+. This phenomenon could have improved the redox cycle, enhanced the SOV formation, facilitated NO decomposition, and accelerated the CO-SCR process. The presence of O2 enhanced the formation of the C(O) complex and improved the activation of the metal site. Mn@La3-Fe1/AC catalyst revealed an excellent NO conversion of 93.8% at 400 °C in the presence of 10% oxygen. The high catalytic performance of MnOx and double exchange behavior of Mn3+ and Mn4+ can increase the number of SOV and improve the catalytic redox properties.

This work presents the role of excess oxygen in CuFeO 2.06 compounds on thermoelectric and optical properties. The CuFeO 2.06 specimens were synthesized by solid state reaction method. X-ray diffraction technique has confirmed the CuFeO 2 structure for the specimens. In particularly, CuFeO 2.06 specimen revealed the structural extension of lattice parameter: a and c . Also, the specimen found increasing excess oxygen of approximately 3% as a resulted enhancement of mixed valence state of Cu + and Cu 2+ ions. XPS showed mixed valence state of the Cu + /Cu 2+ ions, and Fe 3+ and Fe 2+ ions was also found in the CuFeO 2.06 specimen. Mixed valence states contributed the co-existence of hole and electron carriers for conduction. Consequently, electrical conductivity of the CuFeO 2.06 specimen increased up to 23 S/cm at 873 K. Also, increasing Seebeck coefficient was shown to be approximately 302 μV/K at 873 K. The CuFeO 2.06 specimen was found power factor to be approximately 2.1 × 10 −4 W/m∙K 2 at 873 K. The indirect optical gap of CuFeO 2.06 (2.40 eV) was lower than that of the CuFeO 2 (2.60 eV). Thus, thermoelectric and optical properties were governed by an existence of excess oxygen. [ABSTRACT FROM AUTHOR]

We have investigated the structure, magnetic, and electrical properties, and the resistance switching effect (RSE) of La2NiO $_{{ {4+\delta }}} compounds with different excess oxygen levels of \delta = 0.004 - 0.031 . Our results showed the structure changes from tetragonal I4/mmm to orthorhombic Fmmm when reducing \delta value from 0.011 to 0.006. The M(H) curves measured at several temperatures exhibit a coexistence of the weak ferromagnetic and antiferromagnetic interactions. Two shoulders on M(T) curves related to the spin and charge ordering have also been observed. These ordering temperatures depend strongly on \delta ) and low ( RL ) values. The resistance change ratio of the samples defined as 100% \times [RH - RL]/RL is found to be about 18%–57%, which depends on the value of $\delta $ in the samples. [ABSTRACT FROM AUTHOR]

Highlights: [•] Excess oxygen has significant impact on crystal structure of Nd2NiO4+δ ceramics. [•] Temperature-stable giant dielectric responses are observed in both ceramics. [•] The small polaronic hopping model is confirmed in oxygen excess ceramics. [ABSTRACT FROM AUTHOR]