Oxygen Tension Research Articles

Tunable charge transport properties in non-stoichiometric SrIrO3 thin films

Delving into the intricate interplay between spin-orbit coupling and Coulomb correlations in strongly correlated oxides, particularly perovskite compounds, has unveiled a rich landscape of exotic phenomena ranging from unconventional superconductivity to the emergence of topological phases. In this study, we have employed pulsed laser deposition technique to grow SrIrO3 (SIO) thin films on SrTiO3 substrates, systematically varying the oxygen content during the post-deposition annealing. X-ray photoelectron spectroscopy (XPS) provided insights into the stoichiometry and spin-orbit splitting energy of Iridium within the SIO film, while high-resolution x-ray studies meticulously examined the structural integrity of the thin films. Remarkably, our findings indicate a decrease in the metallicity of SIO thin films with reduced annealing O2 partial pressure. Furthermore, we carried out magneto-transport studies on the SIO thin films, the results revealed intriguing insights into spin transport as a function of oxygen content. The tunability of the electronic band structure of SIO films with varying oxygen vacancy is correlated with the density functional theory calculations. Our findings elucidate the intricate mechanisms dictating spin transport properties in SIO thin films, offering invaluable guidance for the design and optimization of spintronic devices based on complex oxide materials. Notably, the ability to tune bandwidth by varying post-annealing oxygen partial pressure in iridate-based spintronic materials holds significant promise for advancing technological applications in the spintronics domain.

Effects of nursing team communication and collaboration on treatment outcomes in intensive care unit patients with severe pneumonia.

Severe pneumonia is a common severe respiratory infection worldwide, and its treatment is challenging, especially for patients in the intensive care unit (ICU). To explore the effect of communication and collaboration between nursing teams on the treatment outcomes of patients with severe pneumonia in ICU. We retrospectively analyzed 60 patients with severe pneumonia who were treated at the ICU of the hospital between January 1, 2021 and December 31, 2023. We compared and analyzed the respiratory mechanical indexes [airway resistance (Raw), mean airway pressure (mPaw), peak pressure (PIP)], blood gas analysis indexes (arterial oxygen saturation, arterial oxygen partial pressure, and oxygenation index), and serum inflammatory factor levels [C-reactive protein (CRP), procalcitonin (PCT), cortisol (COR), and high mobility group protein B1 (HMGB1)] of all patients before and after treatment. Before treatment, there was no significant difference in respiratory mechanics index and blood gas analysis index between 2 groups (P > 0.05). However, after treatment, the respiratory mechanical indexes of patients in both groups were significantly improved, and the improvement of Raw, mPaw, plateau pressure, PIP and other indexes in the combined group after communication and collaboration with the nursing team was significantly better than that in the single care group (P < 0.05). The serum CRP and PCT levels of patients were significantly decreased, and the difference was statistically significant compared with that of nursing group alone (P < 0.05). The levels of serum COR and HMGB1 before and after treatment were also significantly decreased between the two groups. The communication and collaboration of the nursing team have a significant positive impact on respiratory mechanics indicators, blood gas analysis indicators and serum inflammatory factor levels in the treatment of severe pneumonia patients in ICU.

Intervention control of aerobic exercise in maintaining quality of life and pulmonary hypertension in hemodialysis patients.

Pulmonary hypertension is a serious complication in the treatment of maintenance hemodialysis patients, which seriously affects the quality of life of patients and threatens their life safety. Prevention, treatment and improvement of pulmonary hypertension are of great significance to improve the quality of life of patients. To investigate the intervention and control of pedal-powered bicycle in maintaining quality of life and pulmonary hypertension in hemodialysis patients. 73 patients with maintenance hemadialysis combined with pulmonary arterial hypertension at a hemodialysis center in a certain hospital from May 2021 to May 2022 are selected. Patients are divided into two groups, 37 cases in the control group (group C) and 36 cases in the intervention group (group I). Patients are divided into two groups, group C is treated with oral administration of betaglandin sodium combined with routine nursing care. Based on group C, group I conducts power cycling exercises. After treatment, group I patients had higher muscle strength, 36-Item Short Form Health Survey scores, and Kidney Disease Targets Areas scores; The 6-minute walk distance test index level was higher and the Borg score was lower; The group I had lower systolic blood pressure, greater vital capacity, higher positive emotion, lower systolic pulmonary artery pressure index level, higher arterial partial oxygen pressure level, lower pulmonary vascular resistance index level, and higher blood oxygen saturation level [158.91 ± 11.89 vs 152.56 ± 12.81, 1795.01 ± 603.18 vs 1907.20 ± 574.15, 24.00 (22.00, 29.00) vs 24.00 (22.00, 28.00), P < 0.001]. Aerobic exercise combined with Western medicine treatment can effectively improve patients' pulmonary hypertension, alleviate their negative emotions, and enable them to achieve a higher level of quality of life.

Kinetics of Vanillin and Vanillic Acid Production from Pine Kraft Lignin

Vanillin (4-hydroxy-3-methoxybenzaldehyde) is the main component of natural vanilla and a relevant substance in the flavoring and aromatic industries. This study presents a kinetic model to explain both vanillin and vanillic acid concentrations achieved in the alkaline oxidation of pine kraft lignin. Considering that they come from the same precursors, this approach allows an understanding of vanillin production with reaction conditions that minimize the vanillic acid pathway directly from the lignin oligomers, thus maximizing vanillin production. This study involves the effects of oxygen partial pressure, temperature, and the presence or absence of a catalyst (CuSO4 and Fe2(SO4)3 mixture) on the vanillin and vanillic acid yields. An adapted reactor (M/K Systems Inc., Williamstown, MA, USA) with a recirculation and spray liquids system was used in the experiments. The experiments were performed using one liter of a solution of NaOH 2 M and 60 g of lignin. During the lignin oxidation reaction, liquid samples were analyzed at different times (from 0 to 200 min). The oxidation products were quantified by liquid chromatography (HPLC). The catalyzed experiments presented higher maximum vanillin yields than the non-catalyzed ones (39.2–39.6% on nitrobenzene oxidation) achieved at 150 °C. A kinetic model is proposed where the kinetic parameters were estimated using Monte Carlo methods, fitting satisfactorily to the experimental results. The statistical analysis of the kinetic parameters showed that all the studied variables significantly affect the vanillin yield.

Dialoxygenation: A Preclinical Trial for Transforming the Artificial Kidney Into an Oxygenator.

Critically ill patients sometimes require tandem application of extracorporeal membrane oxygenation (ECMO) and continuous renal replacement therapy (CRRT) which is easier and cheaper. We aimed to transform the kidney membrane into a lung membrane by adding hydrogen peroxide (H2O2) to the dialysate as the oxygen source. A solution containing H2O2 and a dialysate fluid mixture was used as the final dialysate. Starting with 100% H2O2 solution and gradually reducing the volume of H2O2, respectively: 50%, 10%, 5%, 4%, 3%, 2%, and 1%. PRISMAFLEX system, Prismaflex M60 set and a bag of packed red blood cells (pRBCs) were the prototype. blood flow rate was about 40 ml/minute and the dialysis rate was about 200 ml/m2/minute/1.73 m2. blood sampling times were; at the beginning (T0), at 15th (T1), 30th (T2), 60th (T3) minutes. Amongst eight attempts H2O2 concentration that increased the partial oxygen pressure (pO2) level significantly in a reasonable period, without any bubbles, was 3%. Methemoglobinemia was not observed in any trial. After the test with 3%, H2O2 in the dialysate fluid decreased progressively without any H2O2 detection at post-membrane blood. Three percent H2O2 solution is sufficient and safe for oxygenation in CRRT systems. With this new oxy-dialysate solution, both pulmonary and renal replacement can be possible viaa single membrane in a simpler manner.

Lower or higher oxygenation targets in the intensive care unit: an individual patient data meta-analysis.

Optimal oxygenation targets for patients with acute hypoxemic respiratory failure in the intensive care unit (ICU) are not clearly defined due to substantial variability in design of previous trials. This study aimed to perform a pre-specified individual patient data meta-analysis of the Handling Oxygenation Targets in the ICU (HOT-ICU) and the Handling Oxygenation Targets in coronavirus disease 2019 (COVID-19) (HOT-COVID) trials to compare targeting a partial pressure of arterial oxygen (PaO2) of 8-12kPa in adult ICU patients, assessing both benefits and harms. We assessed 90-day all-cause mortality and days alive without life support in 90days using a generalised mixed model. Heterogeneity of treatment effects (HTE) was evaluated in 14 subgroups, and results graded using the Instrument to assess the Credibility of Effect Modification Analyses (ICEMAN). At 90days, mortality was 40.4% (724/1792) in the 8kPa group and 40.9% (733/1793) in the 12kPa group (risk ratio, 0.99; 95% confidence interval [CI] 0.92-1.07; P = 0.80). No difference was observed in number of days alive without life support. Subgroup analyses indicated more days alive without life support in COVID-19 patients targeting 8kPa (P = 0.04) (moderate credibility), and lower mortality (P = 0.03) and more days alive without life support (P = 0.02) in cancer-patients targeting 12kPa (low credibility). This study reported no overall differences comparing a PaO2 target of 8-12kPa on mortality or days alive without life support in 90days. Subgroup analyses suggested HTE in patients with COVID-19 (moderate credibility) and cancer (low credibility).

Atomistic structures and stabilities of MgAl2O4 surfaces under processing conditions: A first-principles thermodynamics study

Surfaces, in contacting ambient environments, are of particular importance for controlling sintering, thin-film growth, and catalytic activity of oxides. Magnesium aluminate spinel (MgAl2O4), an essential oxide for both functional and structural ceramics, has attracted considerable attentions across diverse scientific fields. Nonetheless, a central challenge in rationally manipulating the properties of MgAl2O4 lies in the atomistic understanding of its surface structures under processing conditions. This study presents comprehensive first-principles calculations of MgAl2O4 (110) and (111) polar surfaces with/without off-stoichiometries. We predict from a thermodynamic model the dependence of surface stabilities on critical processing parameters, namely the oxygen partial pressure (PO2) and temperature (T). The findings indicate that at typical sintering temperatures, the non-stoichiometric (110) surface transits from Al/Mg-rich to O-rich with increasing PO2. In contrast, the non-stoichiometric (111) surface stably terminates in a Mg-rich configuration at low PO2, gradually shifting to Al-rich and then to Mg/O-rich as PO2 increases. The correlation between surface off-stoichiometry and stability is elucidated through electronic structure analysis. The investigation offers fundamental insights into surface structures and physicochemical behavior of MgAl2O4, thereby facilitating the rational processing control of complex oxides for applications in catalysis and electronics.

Early single session of hyperbaric oxygen therapy mitigates renal apoptosis in lipopolysaccharides-induced endotoxemia in rats.

Sepsis-associated acute kidney injury (SA-AKI) is a prominent sepsis complication, often resulting in adverse clinical outcomes. Hyperbaric oxygen therapy (HBOT), known for its anti-inflammatory characteristics, antioxidant effects, and ability to deliver high oxygen tension to hypo-perfused tissues, offers potential benefits for SA-AKI. This study investigated whether HBOT improved renal injury in sepsis and elucidated its underlying mechanisms. A lipopolysaccharide (LPS)-induced endotoxemia model was established using 8-week-old C57BL/6 mice. Thirty minutes post-LPS administration, a group of mice underwent HBOT at a 2.5 atmospheric pressure absolute with 100% oxygen for 60 minutes. After 24 hours, all mice were euthanized for measurements. Our results demonstrated that HBOT effectively mitigated renal tubular cell apoptosis. Additionally, HBOT significantly reduced phosphorylated p53 proteins and cytochrome C levels, suggesting that HBOT may attenuate renal apoptosis by impeding p53 activation and cytochrome C release. Notably, HBOT preserved manganese-dependent levels of superoxide dismutase, an antioxidant enzyme, compared to the LPS group. Furthermore, transforming growth factor beta (TGF-β)/Smad4 and alpha smooth muscle actin expressions were significantly reduced in the LPS + HBOT group. An early single session of HBOT exhibited renoprotective effects in LPS-induced endotoxemia mice models by suppressing p53 activation and cytochrome C levels to mitigate apoptosis. The observed TGF-β decrease, downstream Smad expression reduction, and antioxidant capacity preservation following HBOT may contribute to these effects.

Microstructural and antibacterial properties of copper oxide deposited on polypropylene fabric by magnetron sputtering

In this study, antibacterial coatings composed of copper and its oxides were deposited on polypropylene (PP) fabrics using magnetron sputtering. The coatings were deposited under varying oxygen partial pressures to facilitate the formation of cupric and cuprous oxides in different quantities. The formation of these oxides was confirmed by the surface morphology (Scanning Electron Microscopy [SEM]) and X-Ray Diffraction (XRD) analysis. Additionally, the antibacterial properties of the coated fabrics were evaluated. The results show that both copper and copper oxides achieved a 4-log reduction in gram-positive bacteria. Inductively Coupled Plasma Mass Spectroscopy (ICPMS) results indicated that the release of copper atoms into water from the coated fabrics was minimal, even after 30 days of immersion.

Impact of oxygen vacancy on luminescence properties of dysprosium-doped zinc oxide thin films

Pristine and dysprosium-doped ZnO thin films, highly c-axis oriented, were grown on a c-Al2O3 substrate using the pulsed laser deposition technique. During the deposition process, the growth was impacted by changes in the oxygen partial pressure. The structural, optical, and compositional properties of the pristine and dysprosium-doped ZnO thin films were systematically characterized using various state-of-the-art experimental techniques. The crystallinity associated with these films was observed to be highly dependent on the oxygen partial pressure maintained during the growth process. An average optical transparency of more than ∼90% in the visible spectral range (i.e., 400–800 nm) was observed for all specimens. For doped specimens, expected intra-4fn emissions of (dysprosium) Dy3+ ions that emanated from the 4F9/2 energy state were observed in room-temperature photoluminescence spectra under direct excitation. The Jacobian-transformed wavelength-to-energy plot for Dy-doped ZnO thin films in the UV-Visible region revealed intriguing findings. Specifically, it depicted a prominent peak at 2.82 eV, indicative of the energy state of Dy3+ ions, alongside intense band-edge emission and various defect-related emissions. The intensity of these transitions was observed to depend on the oxygen partial pressure kept during deposition. An x-ray photoelectron spectroscopy analysis of the doped specimen confirmed the +3 oxidation state of dysprosium into the ZnO matrix. These results provide a promising approach for controlling the doping and growth strategy of Dy-doped ZnO thin films, thereby opening up a wide range of applications and enhancement for next-generation optoelectronic devices.

Nuclear factor erythroid 2-related factor 2 activation in streptozotocin-induced diabetic rats normalize renal hemodynamics and oxygen consumption

Background: Diabetic kidney disease is a major contributor to end stage renal disease. A change in kidney oxygen homeostasis leading to decreased tissue oxygen tension is an important factor initiating alterations in kidney function in diabetes. However, the mechanism contributing to changed oxygen homeostasis is still unclear. Hyperglycemia-induced production of reactive oxygen species and an altered response to them have previously been demonstrated. In the present study, chronic treatment with DL-sulforaphane to induce nuclear factor erythroid 2-related factor 2 (Nrf2) expression, a master transcriptional regulator binding to antioxidant response elements inducing increased protection against reactive oxygen species, is studied. Methods: Sprague–Dawley rats were made diabetic using streptozotocin and either left untreated or received daily subcutaneous injections of DL-sulforaphane for 4 weeks. Age-matched non-diabetic rats served as controls. After 4 weeks of treatment, rats were anesthetized using thiobutabarbital, and kidney functions were studied in terms of glomerular filtration rate (GFR), renal blood flow (RBF), sodium transport, kidney oxygen consumption, and kidney oxygen tension. Mitochondria was isolated from kidney cortical tissue and investigated using high-resolution respirometry. Results: GFR was increased in diabetics but not RBF resulting in increased filtration fraction in diabetics. DL-sulforaphane treatment did not affect RBF and GFR in controls but decreased the same parameters in diabetics. Increased GFR resulted in increased sodium transport and oxygen consumption, hence decreased efficiency in diabetics compared to controls. Increased oxygen consumption in diabetics resulted in decreased cortical tissue oxygen tension. DL-sulforaphane treatment decreased oxygen consumption in diabetics, whereas transport efficiency was not significantly affected. DL-sulforaphane treatment increased cortical pO2 in diabetics. Conclusions: DL-sulforaphane treatment affects renal hemodynamics, improving cortical oxygen tension but not mitochondrial efficiency.

Nuclear factor erythroid 2-related factor 2 activation in streptozotocin-induced diabetic rats normalize renal hemodynamics and oxygen consumption

Background: Diabetic kidney disease is a major contributor to end stage renal disease. A change in kidney oxygen homeostasis leading to decreased tissue oxygen tension is an important factor initiating alterations in kidney function in diabetes. However, the mechanism contributing to changed oxygen homeostasis is still unclear. Hyperglycemia-induced production of reactive oxygen species and an altered response to them have previously been demonstrated. In the present study, chronic treatment with DL-sulforaphane to induce nuclear factor erythroid 2-related factor 2 (Nrf2) expression, a master transcriptional regulator binding to antioxidant response elements inducing increased protection against reactive oxygen species, is studied. Methods: Sprague–Dawley rats were made diabetic using streptozotocin and either left untreated or received daily subcutaneous injections of DL-sulforaphane for 4 weeks. Age-matched non-diabetic rats served as controls. After 4 weeks of treatment, rats were anesthetized using thiobutabarbital, and kidney functions were studied in terms of glomerular filtration rate (GFR), renal blood flow (RBF), sodium transport, kidney oxygen consumption, and kidney oxygen tension. Mitochondria was isolated from kidney cortical tissue and investigated using high-resolution respirometry. Results: GFR was increased in diabetics but not RBF resulting in increased filtration fraction in diabetics. DL-sulforaphane treatment did not affect RBF and GFR in controls but decreased the same parameters in diabetics. Increased GFR resulted in increased sodium transport and oxygen consumption, hence decreased efficiency in diabetics compared to controls. Increased oxygen consumption in diabetics resulted in decreased cortical tissue oxygen tension. DL-sulforaphane treatment decreased oxygen consumption in diabetics, whereas transport efficiency was not significantly affected. DL-sulforaphane treatment increased cortical pO2 in diabetics. Conclusions: DL-sulforaphane treatment affects renal hemodynamics, improving cortical oxygen tension but not mitochondrial efficiency.

Bulk photovoltaic effect in Cu-doped LiNbO3 single crystals with controlled oxidation state

Abstract We investigate the bulk photovoltaic (PV) effect of Cu-doped LiNbO3 single crystals with various oxidation states of Cu. The Cu-doped samples exhibit the PV response under below-bandgap excitation, and the onset of photocurrent shifts depending on partial oxygen pressures (pO2) during the annealing treatment. Open-circuit voltages (V oc) under simulated sunlight (AM 1.5G) illumination are changed by pO2, and crystals annealed at pO2 = 1.0 × 10−10 atm exhibit the highest V oc of 1,700 V. Moreover, density functional theory (DFT) calculations for Cu-doped LiNbO3 cells with Cu2+ on the Li site and the Nb site indicate that half-filled gap states derived from 3d orbitals of Cu are formed within the bandgap. Based on Glass coefficients obtained by the analyses of polarization angle-dependent photocurrent densities and the DFT calculations, we consider that Cu2+ on the Li site is the major active site for the generation and separation of electron-hole pairs under visible light at hν = 2.4 eV.

Bulk photovoltaic effect in Cu-doped LiNbO3 single crystals with controlled oxidation state

Abstract We investigate the bulk photovoltaic (PV) effect of Cu-doped LiNbO3 single crystals with various oxidation states of Cu. The Cu-doped samples exhibit the PV response under below-bandgap excitation, and the onset of photocurrent shifts depending on partial oxygen pressures (pO2) during the annealing treatment. Open-circuit voltages (V oc) under simulated sunlight (AM 1.5G) illumination are changed by pO2, and crystals annealed at pO2 = 1.0 × 10−10 atm exhibit the highest V oc of 1,700 V. Moreover, density functional theory (DFT) calculations for Cu-doped LiNbO3 cells with Cu2+ on the Li site and the Nb site indicate that half-filled gap states derived from 3d orbitals of Cu are formed within the bandgap. Based on Glass coefficients obtained by the analyses of polarization angle-dependent photocurrent densities and the DFT calculations, we consider that Cu2+ on the Li site is the major active site for the generation and separation of electron-hole pairs under visible light at hν = 2.4 eV.

Tunable charge transport properties in non-stoichiometric SrIrO3 thin films.

Delving into the intricate interplay between spin-orbit coupling and Coulomb correlations in strongly correlated oxides, particularly perovskite compounds, has unveiled a rich landscape of exotic phenomena ranging from unconventional superconductivity to the emergence of topological phases. In this study, we have employed pulsed laser deposition (PLD) technique to grow SrIrO3 (SIO) thin films on SrTiO3 substrates, systematically varying the oxygen content during the post-deposition annealing. X-ray Photoelectron Spectroscopy (XPS) provided insights into the stoichiometry and spin-orbit splitting energy of Iridium within the SIO film, while high-resolution X-ray studies meticulously examined the structural integrity of the thin films. Remarkably, our findings indicate a decrease in the metallicity of SIO thin films with reduced annealing O2 partial pressure. Furthermore, we carried out magneto-transport studies on the SIO thin films, the results revealed intriguing insights into spin transport as a function of oxygen content. The tunability of the electronic band structure of SrIrO3 films with varying oxygen vacancy is correlated with the DFT calculations. Our findings elucidate the intricate mechanisms dictating spin transport properties in SrIrO3 thin films, offering invaluable guidance for the design and optimization of spintronic devices based on complex oxide materials. Notably, the ability to tune bandwidth by varying post-annealing oxygen partial pressure in iridate-based spintronic materials holds significant promise for advancing technological applications in the spintronics domain.&#xD.

Mitochondrial oxygen tension in critically ill patients receiving red blood cell transfusions: a multicenter observational cohort study

PurposeCurrently, there is no marker of efficacy of red blood cell (RBC) transfusion. This study describes the impact of RBC transfusion on mitochondrial oxygen tension (mitoPO2) and mitochondrial oxygen consumption (mitoVO2) in critically ill patients with anemia.MethodsCritically ill patients with a hemoglobin concentration < 10 g/dL, for whom a single RBC unit had been ordered, were included. MitoPO2 was measured with the COMET device immediately before RBC transfusion, 0.5 h, 1 h, 3 h, and 24 h after RBC transfusion. MitoVO2 was calculated from dynamic mitoPO2 measurements during cessation of local oxygen supply.ResultsSixty-three patients participated, median age 64.0 (interquartile range (IQR) 52.3–72.8) years, median hemoglobin concentration before transfusion 7.4 (IQR 7.1–7.7) g/dL. Median mitoPO2 values were 55.0 (IQR 49.6–63.0) mmHg before RBC transfusion, 51.0 (IQR 41.5–61.2) directly after and 67.3 (IQR 41.6–83.7) at 24 h after RBC transfusion. Median mitoVO2 values were 3.3 (IQR 2.1–5.9) mmHg/s before RBC transfusion, 3.7 (IQR 2.0–5.1) mmHg/s directly after, and 3.1 (IQR 2.5–4.8) mmHg/s 24 h after RBC transfusion. In the higher Hb concentration group (> 7 g/dL), we saw a dissociation of the effect of RBC transfusion on mitoPO2 versus on mitoVO2 values. MitoPO2 and mitoVO2 values were not associated with commonly used parameters of tissue perfusion and oxygenation.ConclusionRBC transfusion did not alter mitoPO2 and mitoVO2 in critically ill patients with anemia. MitoPO2 and mitoVO2 values were not notably associated with Hb concentrations, parameters of severity of illness and markers of tissue perfusion or oxygenation. Given the high baseline value, it cannot be excluded nor confirmed whether RBC can improve low mitoPO2.Trial registration number NCT03092297 (registered 27 March 2017)

Development of room-temperature operable TiO2-x-based hydrogen gas sensor with light irradiation

In this research work, TiO2-x-thin films are deposited through a radio-frequency magnetron sputtering technique by varying the oxygen partial pressure (pO2) of 6.0 %, 6.4 %, and 6.8 %. The X-ray diffraction analysis depicts the formation of the anatase phase of the annealed thin film with a high crystalline nature. The existence of higher oxygen vacancies and surface roughness are confirmed by the X-ray photoelectron spectroscopy and the atomic force microscopy analyses, respectively, in the 6.0 % pO2 grown thin film. At room temperature (30 °C) and dark conditions, the optimized TiO2-x-based hydrogen gas sensor device depicts a notable response of 22.9 % on exposure to 100 ppm of H2 gas. The irradiation of the ultra-violet (UV) light (λ = 365 nm) on the sensing material promotes desorption of the oxygen species and hence improves the responsivity of the sample. The highest responsivity of 87.7 %, along with faster response and recovery time of 9.4 s and 7.8 s, respectively, is achieved under the UV light irradiation and 100 ppm of H2 gas for the sample grown at 6.0 % pO2, which signifies its potential for the development of room temperature operable hydrogen gas sensor.

Features of electrical transport and H/D isotope effects in the proton-conducting electrolyte BaCe0.7Zr0.1Y0.1Yb0.1O3-δ

The electrical properties of the proton-conducting electrolyte BaCe0.7Zr0.1Y0.1Yb0.1O3-δ were studied using the 4-probe direct current (DC) method depending on temperature and oxygen partial pressure in the atmospheres, humidified with H2O and D2O. Ionic and electron hole contributions to the electrical conductivity were determined, and the transport numbers of charge carriers were calculated. It is shown that in air conditions BaCe0.7Zr0.1Y0.1Yb0.1O3-δ is a mixed ion-electron hole conductor. The contribution of electron hole conductivity decreases with the decrease of temperature and oxygen partial pressure. A significant isotope H/D effect in the electrical conductivity is observed for all investigated conditions expressed in the decrease in conductivity in D2O-containing atmospheres with the increase of activation energy values. Replacing H2O with D2O leads to decrease in the ion transport numbers and ionic conductivity values, while the electron hole conductivity remains almost the same.

Short communication: Maintained visual performance in birds under high altitude hypoxia

Birds are highly dependent on their vision for orientation and navigation. The avian eye differs from the mammalian eye as the retina is avascular, leaving the inner, highly metabolically active layers with a very long diffusion distance to the oxygen supply. During flight at high altitudes, birds face a decrease in environmental oxygen partial pressure, which leads to a decrease in arterial oxygen levels. Since oxygen perfusion to the retina is already limited in birds, we hypothesize that visual function is impaired by low oxygen availability. However, the visual performance of birds exposed to hypoxia has not been evaluated before. Here, we assess the optomotor response (OMR) in zebra finches under simulated high-altitude hypoxia (10%) and show that the OMR is largely maintained under hypoxia with only a modest reduction in OMR, demonstrating that birds can largely maintain visual function at high altitudes. The method of our study does not provide insight into the mechanisms involved, but our findings suggest that birds have evolved physiological mechanisms for retinal function at low tissue oxygen levels.

High-flow nasal cannula oxygen therapy for mild-moderate acute respiratory failure in patients with blunt chest trauma: An exploratory descriptive study

ObjectiveThe use of high-flow nasal cannula (HFNC) oxygen therapy is gaining popularity for the treatment of acute respiratory failure (ARF). However, limited evidence exists regarding the effectiveness of HFNC for hypoxemic ARF in patients with blunt chest trauma (BCT). MethodsThis retrospective analysis focused on BCT patients with mild-moderate hypoxemic ARF who were treated with either HFNC or non-invasive ventilation (NIV) in the emergency medicine department from January 2021 to December 2022. The primary endpoint was treatment failure, defined as either invasive ventilation, or a switch to the other study treatment (NIV for patients in the NFNC group, and vice-versa). ResultsA total of 157 patients with BCT (72 in the HFNC group and 85 in the NIV group) were included in this study. The treatment failure rate in the HFNC group was 11.1% and 16.5% in the NIV group - risk difference of 5.36% (95% CI, −5.94–16.10%; P = 0.366). The most common cause of failure in the HFNC group was aggravation of respiratory distress. While in the NIV group, the most common reason for failure was treatment intolerance. Treatment intolerance in the HFNC group was significantly lower than that in the NIV group (1.4% vs 9.4%, 95% CI 0.40–16.18; P = 0.039). Univariate logistic regression analysis showed that chronic respiratory disease, abbreviated injury scale score (chest) (≥3), Acute Physiology and Chronic Health Evaluation II score (≥15), partial arterial oxygen tension /fraction of inspired oxygen (≤200) at 1 h of treatment and respiratory rate (≥32 /min) at 1 h of treatment were risk factors associated with HFNC failure. ConclusionIn BCT patients with mild-moderate hypoxemic ARF, the usage of HFNC did not lead to higher rate of treatment failure when compared to NIV. HFNC was found to offer better comfort and tolerance than NIV, suggesting it may be a promising new respiratory support therapy for BCT patients with mild-moderate ARF.