Oxygen Tension Research Articles

Goal-Directed Fluid Therapy Using Pulse Pressure Variation in Thoracic Surgery Requiring One-Lung Ventilation: A Randomized Controlled Trial.

Background: Intraoperative fluid management based on pulse pressure variation has shown potential to reduce postoperative pulmonary complications (PPCs) and improve clinical outcomes in various surgical settings. However, its efficacy and safety have not been assessed in patients undergoing thoracic surgery with one-lung ventilation. Methods: Patients scheduled for pulmonary lobectomy using uniportal video-assisted thoracic surgery approach were randomly assigned to two groups. In the PPV group, fluid administration was guided by the pulse pressure variation parameter, while in the near-zero group, it was guided by conventional hemodynamic parameters. The primary outcome was the partial pressure of oxygen (PaO2)/ fraction of inspired oxygen (FiO2) ratio 15 min after extubation. The secondary outcomes included extubation time, the incidence of postoperative pulmonary complications in the first three postoperative days, and the length of hospital stay. Results: The PaO2/FiO2 ratio did not differ between the two groups (364.48 ± 38.06 vs. 359.21 ± 36.95; p = 0.51), although patients in the PPV group (n = 44) received a larger amount of both crystalloids (1145 ± 470.21 vs. 890 ± 459.31, p = 0.01) and colloids (162.5 ± 278.31 vs 18.18 ± 94.68, p = 0.002) compared to the near-zero group (n = 44). No differences were found in extubation time, type and number of PPCs, and length of hospital stay. Conclusions: PPV-guided fluid management in thoracic surgery requiring one-lung ventilation does not improve pulmonary gas exchange as measured by the PaO2/FiO2 ratio and does not seem to offer clinical benefits. Additionally, it results in increased fluid administration compared to fluid management based on conventional hemodynamic parameters.

A comprehensive modeling, analysis, and optimization of two phase, non–isobaric, and non–isothermal PEM fuel cell

This study models a non-isobaric, non-isothermal two-phase flow in a Polymer Electrolyte Membrane Fuel Cell (PEM-FC), focusing on conservation equations for mass, energy, and momentum across its components. Verification involves comparing PEM-FC performance and temperature distribution with experimental and literature data, showing consistent agreements. Results indicate that increasing cathode channel pressure enhances membrane moisture and reduces power loss. Higher oxygen partial pressure improves PEM-FC performance, whereas increased anode channel pressure heightens ohmic losses and lowers output voltage. Temperature distribution reveals highest temperatures near the cathode catalyst layer due to electrochemical reactions. Adjusting pressures in cathode and anode channels affects these temperatures accordingly. PEM-FC power density is optimized using various algorithms, with simulated annealing proving most effective. Optimal values for gas diffusion layer thickness, electrode porosity, and inlet humidity are determined. Under constant current density, power density increases by 6 % compared to baseline conditions, demonstrating effective parameter optimization for enhancing PEM-FC performance.

Ventilatory and Perceived Ergogenic Effects of Mandibular Forward Repositioning During Running at Maximal Oxygen Uptake Intensity.

Cardoso, F, Costa, MJ, Colaço, P, Vilas-Boas, JP, Pinho, JC, Pyne, DB, and Fernandes, RJ. Ventilatory and perceived ergogenic effects of mandibular forward repositioning during running at maximal oxygen uptake intensity. J Strength Cond Res XX(X): 000-000, 2024-Wearing an intraoral dental splint may enhance ventilatory function and exercise performance. Nineteen runners performed on a 400-m outdoor track: (a) an incremental protocol to assess the velocity at maximal oxygen uptake (vV̇ o2 max) and (b) 2 square wave bouts wearing 2 intraoral splints (with and without mandibular forward repositioning). The time until exhaustion at vV̇ o2 max (TLimv V̇ o2 max), ventilatory variables, oxygen uptake (V̇ o2 ) kinetics, energetic profiling, perceived exertion and kinematics, were all measured. Ventilatory data were assessed breath-by-breath and perceived exertion evaluated using the Borg 6-20-point scale at the end of TLimv V̇ o2 max bouts. Images were recorded by video cameras (120 Hz) and kinematic measures retrieved using Kinovea. A paired t test was computed for comparison of splints ( p ≤ 0.05). With (vs. without) mandibular forward repositioning, runners increased their TLimv V̇ o2 max by ∼6% ( p = 0.03), coupled with higher ventilation (151 ± 22 vs. 147 ± 23 L·min -1 , p = 0.04), end-tidal oxygen tension (114.3 ± 3.7 vs. 112.9 ± 3.9 mm Hg, p = 0.003), and lower inspiratory time (0.526 ± 0.083 vs. 0.540 ± 0.090 seconds, p = 0.02), despite similar V̇ o2 kinetics (e.g., 49.0 ± 8.7 vs. 47.7 ± 8.6 ml∙kg∙min -1 of fast component amplitude) being observed. The energy expenditure was ∼8% higher ( p = 0.03) with the mandible forward, coupled with lower perceived exertion scores ( p = 0.04). Mandibular forward repositioning was effective in acutely improving running performance at vV̇ o2 max with ergogenic effects on ventilatory and perceived variables.

The role of tissue oxygenation in obesity-related cardiometabolic complications

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

Predictive Hypoxemic Threshold for Tolerating the Apnea Test While Assessing Death by Neurological Criteria

Abstract Background The apnea test (AT) plays a vital role in diagnosing brain death by evaluating the absence of spontaneous respiratory activity. It entails disconnecting the patient from mechanical ventilation to raise the CO2 partial pressure and lower the pH. Occasionally, the AT is aborted because of safety concerns, such as hypoxemia and hemodynamic instability, to prevent worsening conditions. However, the exact oxygen partial pressure level needed before commencing AT, indicating an inability to tolerate the test, is still uncertain. This study seeks to determine pre-AT oxygen levels linked with a heightened risk of test failure. Methods We conducted a retrospective cohort study involving patients suspected of having brain death at the Tel Aviv Medical Center from 2010 to 2022. The primary outcome was defined as an arterial partial O2 pressure (PaO2) level of 60 mmHg or lower at the conclusion of the AT. This threshold is significant because it marks the point at which the saturation curve deflects, potentially leading to rapid deterioration in the patient’s oxygen saturation. Results Among the 70 patients who underwent AT, 7 patients met the primary diagnostic criteria. Patients with a PaO2 ≤ 60 mmHg at the conclusion of the AT exhibited a significantly lower initial median PaO2 of 243.7 mmHg compared with those with higher pre-AT PaO2 levels of 374.8 mmHg (interquartile range 104.65–307.00 and interquartile range 267.8–444.9 respectively, P value = 0.0041). Pre-AT PaO2 levels demonstrated good discriminatory ability for low PaO2 levels according to the receiver operating characteristic (ROC) curve, with an area under the curve of 0.76 (95% confidence interval 0.52–0.99). Conclusions PaO2 values at the conclusion of the AT are closely associated with PaO2 values at the beginning of the test. Establishing a cutoff value of approximately 300 mmHg PaO2 at the onset of AT may assist in avoiding saturation drops below 90%.

Understanding the significance of oxygen tension on the biology of Plasmodium falciparum blood stages: From the human body to the laboratory

Plasmodium falciparum undergoes sequestration within deep tissues of the human body, spanning multiple organ systems with differing oxygen (O2) concentrations. The parasite is exposed to an even greater range of O2 concentrations as it transitions from the human to the mosquito host, suggesting a high level of plasticity as it navigates these different environments. In this review, we explore factors that may contribute to the parasite’s response to different environmental O2 concentrations, recognizing that there are likely multiple pieces to this puzzle. We first review O2-sensing mechanisms, which exist in other apicomplexans such as Toxoplasma gondii and consider whether similar systems could exist in Plasmodium. Next, we review morphological and functional changes in P. falciparum’s mitochondrion during the asexual-to-sexual stage transition and discuss how these changes overlap with the parasite’s access to O2. We then delve into reactive oxygen species (ROS) as ROS production is influenced by O2 availability and oxidative stress impacts Plasmodium intraerythrocytic development. Lastly, given that the primary role of the red blood cell (RBC) is to deliver O2 throughout the body, we discuss how changes in the oxygenation status of hemoglobin, the RBC’s O2-carrying protein and key nutrient for Plasmodium, could also potentially impact the parasite’s growth during intraerythrocytic development. This review also highlights studies that have investigated P. falciparum biology under varying O2 concentrations and covers technical aspects related to P. falciparum cultivation in the lab, focusing on sources of technical variation that could alter the amount of dissolved O2 encountered by cells during in vitro experiments. Lastly, we discuss how culture systems can better replicate in vivo heterogeneity with respect to O2 gradients, propose ideas for further research in this area, and consider translational implications related to O2 and malaria.

Effects of Dexmedetomidine in Improving Oxygenation and Reducing Pulmonary Shunt in High-Risk Pediatric Patients Undergoing One-Lung Ventilation for Thoracic Surgery: A Double-Blind Randomized Controlled Trial.

Background and objectives Pediatric thoracic surgery has unique considerations due to the immaturity of the respiratory system anatomically and physiologically, which presents technical and pharmacological considerations, including the very common technique of one-lung ventilation (OLV), which causes serious complications in children. Therefore, we investigated the effects of dexmedetomidine on oxygenation and pulmonary shunt fraction (Qs/Qt) in high-risk pediatric patients undergoing OLV for thoracic surgery. This randomized controlled trial aimed to investigate dexmedetomidine's effect on the partial pressure of arterial oxygen (PaO2) and pulmonary shunt fraction (Qs/Qt). Methods A total of 63 children underwent thoracic surgery with OLV and were divided into two groups. The dexmedetomidine group (group Dex, n = 32) received dexmedetomidine (0.4 μg/kg/hour), and the placebo group (group placebo, n = 31) received normal saline. Two arterial and central venous blood samples were taken for arterial and venous blood gas analysis at four time points: T1 (10 minutes after mechanical ventilation of total lung ventilation), T2 (10 minutes after OLV), T3 (60 minutes after OLV), and T4 (20 minutes after the end of OLV). At these intervals, the following parameters were measured: PaO2, Qs/Qt, mean arterial pressure (MAP), heart rate (HR), and peak inspiratory pressure (PIP). Results The two groups had no significant differences in FEV1/FVC and baseline pulmonary shunt fraction (Qs/Qt). Dexmedetomidine significantly improved PaO2 compared with placebo during OLV (T2 and T3). There was a significant decrease in Qs/Qt compared with placebo during OLV (T2, T3, and T4). There was a decrease in PIP compared with placebo during OLV (T2 and T3). No statistically significant differences in MAP or HR were observed between the groups. Conclusion Infusion of dexmedetomidine during OLV in high-risk pediatric thoracic surgery reduces shunt and pulmonary shunt fraction Qs/Qt, improves PaO2 and body oxygenation, reduces PIP and pressure load, and maintains hemodynamic stability (MAP, HR).

Estimation of outpatient SARS-CoV-2 reinfection and recurrence rates and associated factors among COVID-19 hospitalized patients over one-year old: a multicenter retrospective cohort study

IntroductionReinfection with SARS-Cov-2 after recovery can occur that most of them don’t require hospitalization. The aim of this study is estimation of out-patient COVID-19 reinfection and recurrence rates and its associated factors among Iranian patients with history of confirmed SARS-Cov-2 infection and hospitalization.MethodsThis study is a retrospective cohort conducted from May 2021 to May 2022 in Iran. The national Medical Care Monitoring Center (MCMC) database, obtained from the Ministry of Health and Medical Education, includes all information about confirmed COVID-19 patients who are hospitalized and diagnosed during the pandemic. Using probability proportional to size sampling from 31 provinces, 1,532 patients over one years of age with a history of hospitalization in the MCMC data are randomly selected. After that, interviews by phone are performed with all of the selected patients using a researcher-made questionnaire about the occurrence of overall reinfection without considering the time of infection occurrence, reinfection occurring at least 90 days after the discharge and recurrence (occurring within 90 days after discharge). Univariate and multivariable Cox regression analyses are performed to assess the factors associated with each index. All of the analyses are performed using Stata software version 16.ResultsIn general, 1,532 phone calls are made, out of which 1,095 individuals are willing to participate in the study (response rate ≃ 71%). After assessing the 1,095 patients with a positive history of COVID-19, the rates of non-hospitalized overall SARS-Cov-2 reinfection, reinfection and recurrence are 122.64, 114.09, and 8.55 per 1,000 person-years, respectively. The age range of 19–64 years (aHR:3.93, 95%CI : 1.24–12.41) and COVID-19-related healthcare worker (aHR: 3.67, 95%CI: 1.77–7.61) are identified as risk factors for reinfection, while having comorbidity, being fully vaccinated, and having a partial pressure of oxygen (PaO2) ≥ 93 mmHg during the initial infection are identified as factors that reduce the risk of non-hospitalized reinfection.ConclusionReinfection due to COVID-19 is possible because of the weakened immune system for various reasons and the mutation of the virus. Vaccination, timely boosters, and adherence to preventive measures can help mitigate this risk.

Effects of N95 Masks Versus Surgical/Loop Masks on Arterial Blood Gases and Adverse Symptoms in Operating Room Staff During Prolonged Usage: A Pilot Study.

The COVID-19pandemic continues to have a catastrophic impact on the global population. N95 masks are commonly used as filtering facepiece respirators for healthcare workers. At the end of long shifts, they have reported headaches, dizziness, fatigue, exhaustion, and physical and mental discomfort. There is a lack of data on the effects of N95 masks on blood gases in healthcare workers who wear masks for longer durations. We analyzed and compared the effects of continuously wearing N95 versus loop/surgical masks on various symptomology parameters and arterial blood gases for longer durations. This was a non-blinded, pilot, observational study at a single academic institution. Utilizing a survey, we collected information on operating room staff volunteers (demographics, mask use, and symptoms) and measured transcutaneous partial pressure carbon dioxide (tcPCO2) and oxygen saturation (SpO2) before and after the subject's shift to identify changes. Thirty-nine subjects enrolled in the study (N95 mask = 13, loop/surgical mask = 26). Overall, 69.2% of the subjects continuously wore a mask for five or more hours on their shift. There was a statistical difference with reported fatigue with exclusively wearing an N95 mask versus a loop/surgical mask (p=0.017). None of the other parameters showed a statistical difference between groups. The tcPCO2 was not statistically different between mask types at the beginning of the shift (p=0.922) or at the end of the shift (p=0.188), although tcPCO2 levels increased. The SpO2 was not statistically different between the mask types at the beginning of the shift (p=0.883) or at the end of the shift (p=0.505) with SpO2 decreasing. Individuals exclusively wearing an N95 mask reported a statistically greater number of complaints of fatigue after their shift. No statistical differences were observed in arterial blood gas parameters measured for SpO2 and tcPCO2 between mask groups. No definitive conclusions can be made due to the small sample size.

Respiratory effects of prone position in COVID-19 acute respiratory distress syndrome differ according to the recruitment-to-inflation ratio: a prospective observational study

BackgroundImprovements in oxygenation and lung mechanics with prone position (PP) in patients with acute respiratory distress syndrome (ARDS) are inconstant. The objectives of the study were (i) to identify baseline variables, including the recruitment-to-inflation ratio (R/I), associated with a positive response to PP in terms of oxygenation (improvement of the ratio of arterial oxygen partial pressure over the inspired oxygen fraction (PaO2/FiO2) ≥ 20 mmHg) and lung mechanics; (ii) to evaluate whether the response to the previous PP session is associated with the response to the next session.MethodsIn this prospective, observational, single-center study in patients who underwent PP for ARDS due to COVID-19, respiratory variables were assessed just before PP and at the end of the session. Respiratory variables included mechanical ventilation settings and respiratory mechanics variables, including R/I, an estimate of the potential for lung recruitment compared to lung overinflation.ResultsIn 50 patients, 201 PP sessions lasting 19 ± 3 h were evaluated. Neuromuscular blockades were used in 116 (58%) sessions. The PaO2/FiO2 ratio increased from 109 ± 31 mmHg to 165 ± 65 mmHg, with an increase ≥ 20 mmHg in 142 (71%) sessions. In a mixed effect logistic regression, only pre-PP PaO2/FiO2 (OR 1.12 (95% CI [1.01–1.24])/every decrease of 10 mmHg, p = 0.034) in a first model and improvement in oxygenation at the previous PP session (OR 3.69 (95% CI [1.27–10.72]), p = 0.017) in a second model were associated with an improvement in oxygenation with PP. The R/I ratio (n = 156 sessions) was 0.53 (0.30–0.76), separating lower- and higher-recruiters. Whereas PaO2/FiO2 improved to the same level in both subgroups, driving pressure and respiratory system compliance improved only in higher-recruiters (from 14 ± 4 to 12 ± 4 cmH2O, p = 0.027, and from 34 ± 11 to 38 ± 13 mL/cmH2O, respectively, p = 0.014).ConclusionsA lower PaO2/FiO2 at baseline and a positive O2-response at the previous PP session are associated with a PP-induced improvement in oxygenation. In higher-recruiters, lung mechanics improved along with oxygenation. Benefits of PP could thus be greater in these patients.

Effects of moderate alcohol consumption and hypobaric hypoxia: implications for passengers’ sleep, oxygen saturation and heart rate on long-haul flights

BackgroundPassengers on long-haul flights frequently consume alcohol. Inflight sleep exacerbates the fall in blood oxygen saturation (SpO2) caused by the decreased oxygen partial pressure in the cabin. We investigated the...

Simulation and deposition of Tungsten oxide (WO3) films using DC sputtering towards UV photodetector for high responsivity

Tungsten trioxide (WO3) detects UV radiation with great sensitivity while disregarding visible light, and it also has excellent electron mobility, allowing for efficient charge transport and fast response times. This work aims to develop a highly sensitive UV photodetector using WO3 material by optimizing the deposition parameter partial oxygen pressure (PaO2) and annealing the samples at various temperatures to determine the best PaO2 and annealing temperature that results in an improvement in the UV photodetector's sensitivity. The material WO3 was coated on glass substrates using DC magnetron sputtering while altering the PaO2 as 6 × 10−2 Pa, 4 × 10−2 -2 Pa, and 2 × 10−2 Pa, and then each as-deposited sample from varied PaO2 was annealed at temperatures ranging from 100°C to 400°C. When the sample's responses were compared, it was observed that the sample deposited at PaO2 2 × 10−2 Pa and annealed at 400 °C exhibited good photodetection capabilities, as evidenced by several characterization techniques such as SEM, XRD, and IV characterization. The work was subsequently carried out by evaluating the sample deposited at PaO2 2 × 10−2 Pa and annealed at 700 °C, which produced a good result for UV photodetection with the device's responsivity of 1e+4 A/W.

Predictive value of diaphragm ultrasound for mechanical ventilation outcome in patients with acute exacerbation of chronic obstructive pulmonary disease.

Acute exacerbation of chronic obstructive pulmonary disease (AECOPD) is often combined with respiratory failure, which increases the patient's morbidity and mortality. Diaphragm ultrasound (DUS) has developed rapidly in the field of critical care in recent years. Studies with DUS monitoring diaphragm-related rapid shallow breathing index have demonstrated important results in guiding intensive care unit patients out of the ventilator. Early prediction of the indications for withdrawal of non-invasive ventilator and early evaluation of patients to avoid or reduce disease progression are very important. To explore the predictive value of DUS indexes for non-invasive ventilation outcome in patients with AECOPD. Ninety-four patients with AECOPD who received mechanical ventilation in our hospital from January 2022 to December 2023 were retrospectively analyzed, and they were divided into a successful ventilation group (68 cases) and a failed ventilation group (26 cases) according to the outcome of ventilation. The clinical data of patients with successful and failed noninvasive ventilation were compared, and the independent predictors of noninvasive ventilation outcomes in AECOPD patients were identified by multivariate logistic regression analysis. There were no significant differences in gender, age, body mass index, complications, systolic pressure, heart rate, mean arterial pressure, respiratory rate, oxygen saturation, partial pressure of oxygen, oxygenation index, or time of inspiration between patients with successful and failed mechanical ventilation (P > 0.05). The patients with successful noninvasive ventilation had shorter hospital stays and lower partial pressure of carbon dioxide (PaCO2) than those with failed treatment, while potential of hydrogen (pH), diaphragm thickening fraction (DTF), diaphragm activity, and diaphragm movement time were significantly higher than those with failed treatment (P < 0.05). pH [odds ratio (OR) = 0.005, P < 0.05], PaCO2 (OR = 0.430, P < 0.05), and DTF (OR = 0.570, P < 0.05) were identified to be independent factors influencing the outcome of mechanical ventilation in AECOPD patients. The DUS index DTF can better predict the outcome of non-invasive ventilation in AECOPD patients.

Thermal Decomposition of Hematite Ore Fines in Air

Thermal decomposition of hematite plays an important role during pelletization and the iron fine‐based smelting processes such as HIsarna and flash shaft smelter. The temperature at which pure hematite decomposition occurs depends on the partial pressure of oxygen in the gaseous atmosphere. In the air, that is, at = 0.21, the hematite decomposes at 1386 °C. In the present work, for an ore of a given composition, the effect of gangue on the thermal decomposition of hematite is experimentally determined using thermogravimetric analysis (TGA). A decomposition temperature of 1320 °C is found in the platinum crucible after analyzing the TGA curve. Thermodynamic calculations have been carried out using FactSage8.1 to investigate the effect of gangue on the stability of hematite. Thermodynamics calculations confirm that the hematite present in the ore decomposes at a lower temperature with the increase in the gangue content. Additionally, if gangue content can affect the temperature at which dissociation of hematite occurs, it is expected that the crucible material can also affect the dissociation. Interestingly most of the reported TGA experiments are performed either in alumina crucibles or it was not reported in the literature. Therefore, the effect of crucible materials, namely alumina and platinum, is also investigated.

Influence of temperature, oxygen partial pressure, and microstructure on the high-temperature oxidation behavior of the SiC Layer of TRISO particles

Tristructural isotropic (TRISO)-coated fuel particles are designed for use in high-temperature gas-cooled nuclear reactors, featuring a structural SiC layer that may be exposed to oxygen-rich environments over 1000 °C. Surrogate TRISO particles were tested in 0.2–20 kPa O2 atmospheres to observe the differences in oxidation behavior. Oxide growth mechanisms remained consistent from 1200–1600 °C for each PO2, with activation energies of 228 ± 7 kJ/mol for 20 kPa O2 and 188 ± 8 kJ/mol for 0.2 kPa O2. At 1600 °C, kinetic analysis revealed a change in oxide growth mechanisms between 0.2 and 6 kPa O2. In 0.2 kPa O2, oxidation produced raised oxide nodules on pockets with nanocrystalline SiC. Oxidation mechanisms were determined using Atom probe tomography. Active SiC oxidation occurred in C-rich grain boundaries with low PO2, leading to SiO2 buildup in porous nodules. This phenomenon was not observed at any temperature in 20 kPa O2 environments.

Positronium image of the human brain in vivo.

Positronium is abundantly produced within the molecular voids of a patient's body during positron emission tomography (PET). Its properties dynamically respond to the submolecular architecture of the tissue and the partial pressure of oxygen. Current PET systems record only two annihilation photons and cannot provide information about the positronium lifetime. This study presents the in vivo images of positronium lifetime in a human, for a patient with a glioblastoma brain tumor, by using the dedicated Jagiellonian PET system enabling simultaneous detection of annihilation photons and prompt gamma emitted by a radionuclide. The prompt gamma provides information on the time of positronium formation. The photons from positronium annihilation are used to reconstruct the place and time of its decay. In the presented case study, the determined positron and positronium lifetimes in glioblastoma cells are shorter than those in salivary glands and those in healthy brain tissues, indicating that positronium imaging could be used to diagnose disease in vivo.

Magnetic and dielectric properties of low‐loss MnZn ferrites with wide temperature stability

AbstractTo meet the needs for higher energy efficiency and a wide operating temperature range of electric vehicles, the low‐loss MnZn ferrites in a wide temperature range have been developed by optimizing the Fe content and the oxygen partial pressure (PO2) during the sintering process in this work. For the optimal sample, power loss at 300 kHz/100mT is 204 kW/m3 at 25°C and remains below 290 kW/m3 in the wide temperature range from ‐10 to 120°C. The loss separation method was employed to clarify the effects of the Fe content and PO2 on power loss. The equivalent circuit model has been employed to fit the complex impedance and it is found that the increase of PO2 enhances both the grain resistance Rg and the grain boundary resistance Rgb. The enhancement of Rgb is mainly responsible for the reduction of eddy current loss and consequently power loss. Dielectric permittivity is as large as about 15000 in this series of samples due to the electric polarization at the rich grain boundaries. Dielectric loss is very low between ‐50 and 150°C and has little contribution to the energy loss.

Dose titration of intravenously administered gamma-hydroxybutyric acid for sedation in Holstein-Friesian calves

Gamma-hydroxybutyric acid (GHB) is a short-chain fatty acid that can potentially provide safe, prolonged sedation with minimal cardiorespiratory effects. This preliminary trial, performed in 10 three-week-old male Holstein-Friesian calves, investigated the effects of GHB administered intravenously over 5 min at a dose of 100 (G100, n=2), 150 (G150, n=4) or 200 mg/kg (G200, n=4). Once lateral recumbency was achieved, scores for sedation depth (range: 0 = no sedation to 3 = marked) and response to noxious stimulation (range: 0 = strong to 3 = absent), heart rate (HR), respiratory rate (RR), mean arterial pressure (MAP) and arterial blood gases were monitored every 15 min until sternal recumbency. Times from end of administration to lateral recumbency and return to sternal/standing positions were recorded. Dose G100 resulted in mild sedation and ataxia without decubitus. Doses G150 and G200 respectively resulted in time to lateral recumbency 8 ± 2 and 9 ± 3 min, lasting 189 ± 41 and 283 ± 29 min, while overall median (range) scores for sedation were 3 (1−3) and 3 (2−3) respectively and response to noxious stimulation 0 (0−3) and 0 (0−3) respectively. The mean ± SD for HR was 110 ± 10 and 106 ± 11 bpm respectively; for MAP 87±9 and 94±5 mmHg respectively; and for RR 28 ± 5 and 26 ± 5 bpm respectively. The mean ± SD for arterial partial pressure of oxygen (PaO2) at these two dose rates was 74 ± 6 and 74 ± 2 mmHg respectively, while the arterial partial pressure of carbon dioxide oxygen (PaCO2) was 53 ± 3 and 47 ± 0.8 mmHg respectively. Based on these preliminary results we conclude that GHB has the potential to be used as a long-acting sedative in calves. Further studies are needed to confirm this.

The anti-inflammatory effects of Fuzapladib in an endotoxemic porcine model.

Endotoxemia is a systemic inflammatory condition caused by lipopolysaccharide (LPS) stimulation, which produces inflammatory cytokines. Fuzapladib (FZP) inhibits the activation of adhesion molecules found on the surface of inflammatory cells, mitigating inflammation. In this study, we evaluated the therapeutic effects of fuzapladib on inflammatory cytokines and cardio-respiratory function using an LPS-induced endotoxemic porcine model. Fifteen pigs were separated into three groups: low-FZP (n=5), high-FZP (n=5), and control (n=5). Pigs were administered LPS under general anesthesia, and complete blood cell count, blood biochemistry, inflammatory cytokines, and cardio-respiratory function were evaluated. Statistical analysis was performed using a linear mixed-effects model and the Steel-Dwass test, with a significance threshold of P<0.05. During the 4 hr experimental period, one pig in the control group and two pigs in the low-FZP group died due to hypoxemia and hypotension. In the early acute changes following LPS administration, the high-FZP group maintained significantly higher arterial oxygen partial pressure and normal blood pressure compared to the control group. Although interleukin-6 levels increased in all groups during the experiment, they were significantly lower in the high-FZP group compared to the control group. Other parameters showed no clinically significant differences. In conclusion, while high-dose fuzapladib did not reduce organ damage in the porcine endotoxemia model, it suppressed interleukin-6 production, delayed the progression of deterioration, and contributed to a reduction in mortality during the observation period.

Defect Structure, Oxygen Ion Conduction, and Conducting Mechanism in Ruddlesden-Popper Sr3Zr2-xMxO7-0.5x (M = Ga, Y, In).

Ruddlesden-Popper (RP)-structured materials based on transition metals with a variable valence, such as Fe, Mn, Ni, and so on, have been well documented for their potential of being used as electrodes in solid-oxide fuel cells. However, RP materials with pure or dominant ionic conduction are rare. Here, a series of Zr-based RP materials Sr3Zr2-xMxO7-0.5x (M = Ga, Y, In) with electrical conductivity as high as 3.25 × 10-3 S cm-1 at 900 °C in air was reported, which represents the highest conductivity for the Zr-based RP materials and is comparable to that of the recently reported In-based RP oxide-ion conductors, such as NdBaInO4-based and La2BaIn2O7-based materials. Under low oxygen partial pressure (pO2), the doped samples show pure ionic conducting behaviors without n-type electronic conductivity. The defect formation energies, local structure around the oxygen vacancies, and oxide-ion-conducting mechanism of the acceptor-doped Sr3Zr2O7-based materials were studied for the first time. The results revealed a two-dimensional oxide ion migration characteristic within the perovskite slabs. This work therefore provides a good reference for developing new oxide-ion conductors in the Zr-based RP-structured materials.