High Oxygen Pressure Research Articles

Effects of hyperbaric oxygen treatment on liver and kidney tissue in chronic arsenic toxicity

Arsenic (As) is a toxic substance that damages the human body through exposure to drinking water. This exposure damages many organs and tissues in the body, especially the liver and kidneys. Hyperbaric oxygen (HBO2) therapy is a treatment method that acts by reducing oxidative stress parameters in tissues with high-pressure oxygen. Based on this, our study aimed to investigate the effectiveness of HBO2 on liver and kidney tissues with chronic arsenic toxicity. In the study 24 male Wistar albino rats (220-300 g, two to three months old) were equally divided into four groups: Control; As; HBO2; and As+HBO2. All animals were housed in individual cages. The toxicity model was created by adding arsenic to drinking water at a dose of 5 mg/kg/day for 60 days. HBO2 was applied 2 ATA pressure for 90 minutes a day for five days. At the end of the study, liver and kidney tissues were taken and stored for analysis. In liver tissue, histopathological showed that arsenic reduced inflammatory cell infiltration, sinusoidal congestion, and hydropic degeneration, while HBO2 increased these measures. Similar results were found by TUNEL method. In kidney tissue, both histopathologic and TUNEL method examinations found similar results with the liver: The As group was more damaged than the As+HBO2 group.

Formation and Detection of High-Pressure Oxygen in Closed Pores of La0.6Sr0.4CoO3-δ Solid Oxide Electrolysis Anodes.

The chemical capacitance of La0.6Sr0.4CoO3−δ (LSC) thin film microelectrodes with different microstructures was investigated upon varying anodic DC voltages. Dense and porous electrodes (open porosity) were prepared by using different parameters during pulsed laser deposition (PLD). Furthermore, electrodes with closed porosity were fabricated by depositing a dense capping layer on a porous film. Electrochemical impedance spectroscopy (EIS) was performed in synthetic air at 460 and 608 °C with anodic DC voltages up to 440 mV. Chemical capacitance values of the electrodes were derived from the obtained spectra. While the chemical capacitance of dense and porous electrodes decreased as expected with increasing anodic overpotential, electrodes with closed pores exhibited very unusual peaks with extremely high values of >8000 F/cm3 at overpotentials of >100 mV. We demonstrate that this huge capacitance increase agrees very well with calculated chemical capacitances deduced from a real gas equation. Hence, we conclude that the formation of highly pressurized oxygen (up to gas pressures of ∼104 bar) in closed pores is responsible for this strong capacitive effect at anodic overpotentials. Such measurements can thus detect and quantify the buildup of high internal gas pressures in closed pores at the anode side of solid oxide electrolysis cells.

Atomic origin of the coexistence of high critical current density and high Tc in CuBa2Ca3Cu4O10+δ superconductors

For cuprate superconductors, a high critical transition temperature (Tc) can be realized in compounds containing multiple CuO2 layers in the unit cell, while a high critical current density (Jc) is rarely sustained above liquid nitrogen temperature. The CuBa2Ca3Cu4O10+δ (Cu-1234) superconductors synthesized under high oxygen pressure incredibly exhibit high Tc (~117 K) and high Jc (>104 A/cm2, 100 K) values. Here, the “double high” traits of Cu-1234 were investigated with advanced scanning transmission electron microscopy. It was revealed that ordering vacancies and plate-like 90° microdomains induced efficient microstructure pinning centers that suppressed vortex flux flow and enhanced Jc. Furthermore, metallic charge-reservoir blocks [Ba2CuO3+δ] were composed of unique compressed [CuO6] octahedra, which induced many holes with 2pz symmetry that significantly decreased the superconducting anisotropy and dramatically enhanced the interlayer coupling that guaranteed a high Jc. On the other hand, optimally doped CuO2 planes inside the thick superconducting blocks [Ca3Cu4O8] maintained a high Tc. Our results are applicable to design and synthesis of new superconductors with “double high” traits.

X3Σg- → b1Σg+ Absorption Spectra of Molecular Oxygen in Liquid Organic Solvents at Atmospheric Pressure.

Spectra and absorption coefficients of the forbidden 765 nm X3Σg- → b1Σg+ transition of molecular oxygen dissolved in organic solvents at atmospheric pressure were recorded over a 5 m path length using a liquid waveguide capillary cell. The results show that it is possible to investigate this weak near-infrared absorption transition in a common liquid hydrocarbon solvent without the need for a potentially dangerous high oxygen pressure. Proof-of-principle data from benzene, toluene, chlorobenzene, bromobenzene, and iodobenzene reveal a pronounced heavy atom effect on this spin-forbidden transition. For example, the absorption coefficient at the band maximum in iodobenzene, (28.9 ± 3.3) × 10-3 M-1 cm-1, is approximately 21 times larger than that in benzene, (1.4 ± 0.1) × 10-3 M-1 cm-1. These absorption measurements corroborate results obtained from O2(X3Σg-) → O2(b1Σg+) excitation spectra of O2(a1Δg) → O2(X3Σg-) phosphorescence, which depended on data from a plethora of convoluted experiments. Spectroscopic studies of molecular oxygen in liquid solvents can help evaluate aspects of the seminal Strickler-Berg approach to treat the effect of solvent on Einstein's A and B coefficients for radiative transitions. In particular, our present results are a key step toward using the O2(X3Σg-) → O2(b1Σg+) transition to evaluate the speculated limiting condition of applying the Strickler-Berg treatment to a highly forbidden process. This latter issue is but one example of how an arguably simple homonuclear diatomic molecule continues to aid the scientific community by providing fundamental physical insight.

Different Doses of Ropivacaine either with Sufentanil or with Dexmedetomidine for Labor Epidural Anesthesia regarding Painless Childbirth: A Retrospective, Multicenter Study

Introduction: Sufentanil is used with ropivacaine in labor pain management but it can have respiratory depression. Dexmedetomidine is effective to maintain hemodynamic stability in parturient women and allow awake intubation. However, dexmedetomidine is suggested only in patients with major cardiovascular disease that mandates stable hemodynamics (Reference ID: 3987541-USFDA). The objective of the study was to compare different doses of ropivacaine either with sufentanil or with dexmedetomidine for epidural anesthesia regarding labor pain management. Methods: Parturient women have received 0.125% ropivacaine with 0.5-μg/mL sufentanil (SR1 cohort, n = 115), or 0.08% ropivacaine with 0.5-μg/mL sufentanil (SR2 cohort, n = 109), or 0.125% ropivacaine with 0.5-μg/mL dexmedetomidine (DR1 cohort, n = 124), or 0.08% ropivacaine with 0.5-μg/mL dexmedetomidine (DR2 cohort, n = 135) for epidural anesthesia during vaginal delivery or cesarean section. Results: At 2-h postpartum, the visual analog scale score of parturient women of the DR2 cohort was fewer than that of parturient women of the SR1 (p < 0.0001, q = 4.162) and the SR2 (p < 0.0001, q = 7.568) cohorts and statistically the same as that of parturient women of the DR1 cohort (p < 0.0001, q = 3.087). Bradycardia and itching were reported in parturient women of the DR2 and the DR1 cohorts while nausea, vomiting, and urinary retention at 6 h were reported in parturient women of the SR1 and the SR2 cohorts. In the DR2 cohort, there were fewer numbers of parturient women with bradycardia (4 vs. 19, p < 0.0001, q = 6.613) and hypotension (2% vs. 1%) than those in the DR1 cohort. The child born by women of the DR2 cohort had high partial arterial pressure of oxygen than those born by women of the DR1 (p < 0.0001, q = 18.663), the SR1 (p < 0.0001, q = 29.366), and the SR2 (p < 0.0001, q = 24.039) cohorts. Discussion/Conclusion: Epidural 0.08% ropivacaine with 0.5-μg/mL dexmedetomidine is an effective and safe anesthetic regimen for hypertensive parturient women and their newborns. Level of Evidence: III. Technical Efficacy Stage: 4.

Biological Effect of Quercetin in Repairing Brain Damage and Cerebral Changes in Rats: Molecular Docking and In Vivo Studies.

This study examined the protective effect of quercetin against high-altitude-induced brain damage in rats. A molecular docking study was performed to investigate the potential effect of quercetin in reducing brain damages through its ability to target the oxidative stress enzymes. Biomarker assessment screening assays were also performed then followed by in vivo studies. Three groups of rats were divided into the control group, an untreated animal model group with induced brain damage, and finally, the quercetin treated group that received quercetin dose equal to 20 mg/kg of their body weights. Molecular docking studies and biomarker assessment screening assays proved the potential effect of quercetin to affect the level of representative biomarkers glutathione (GSH), glutathione reductase (GR), glutathione-S-transferase (GST), glutathione peroxidase (GPx), superoxide dismutase (SOD), catalase (CAT), and malondialdehyde (MDA). Additionally, the protective effect of quercetin against high altitude, low pressure, and low oxygen was also investigated by exploring the brain histopathology of experimental rats. Brain damage was observed in the untreated animal model group. After treatment with quercetin, the cerebral edema in the brain tissues was improved significantly, confirming the protective effects of quercetin. Therefore, quercetin can be used as a natural food additive to protect from the highaltitude-induced brain damage.

Oxygen‐Driven Metal–Insulator Transition in SrNbO3 Thin Films Probed by Infrared Spectroscopy

AbstractThe occurrence of oxygen‐driven metal–insulator‐transition (MIT) in SrNbO3 (SNO) thin films epitaxially grown on (110)‐oriented DyScO3 has been reported. SNO films are fabricated by the pulsed laser deposition technique at different partial O2 pressure to vary the oxygen content and their structural, optical, and transport properties are probed. SNO unit cell has been found to shrink vertically as the oxygen content increases but keeping the epitaxial matching with the substrate. The results of Fourier‐transform infra‐red spectroscopy show that highly oxygenated SNO samples (i.e., grown at high oxygen pressure) show distinct optical conductivity behavior with respect to oxygen deficient films, hence demonstrating the insulating character of the formers with respect to those fabricated with lower pressure conditions. Tailoring the optical absorption and conductivity of strontium niobate epitaxial films across the MIT will favor novel applications of this material.

Adaptation of the Oxygen Sensing System during Lung Development.

During gestation, the most drastic change in oxygen supply occurs with the onset of ventilation after birth. As the too early exposure of premature infants to high arterial oxygen pressure leads to characteristic diseases, we studied the adaptation of the oxygen sensing system and its targets, the hypoxia-inducible factor- (HIF-) regulated genes (HRGs) in the developing lung. We draw a detailed picture of the oxygen sensing system by integrating information from qPCR, immunoblotting, in situ hybridization, and single-cell RNA sequencing data in ex vivo and in vivo models. HIF1α protein was completely destabilized with the onset of pulmonary ventilation, but did not coincide with expression changes in bona fide HRGs. We observed a modified composition of the HIF-PHD system from intrauterine to neonatal phases: Phd3 was significantly decreased, while Hif2a showed a strong increase and the Hif3a isoform Ipas exclusively peaked at P0. Colocalization studies point to the Hif1a-Phd1 axis as the main regulator of the HIF-PHD system in mouse lung development, complemented by the Hif3a-Phd3 axis during gestation. Hif3a isoform expression showed a stepwise adaptation during the periods of saccular and alveolar differentiation. With a strong hypoxic stimulus, lung ex vivo organ cultures displayed a functioning HIF system at every developmental stage. Approaches with systemic hypoxia or roxadustat treatment revealed only a limited in vivo response of HRGs. Understanding the interplay of the oxygen sensing system components during the transition from saccular to alveolar phases of lung development might help to counteract prematurity-associated diseases like bronchopulmonary dysplasia.

Research on Separation and Extraction of Valuable Metals from Complex Non-ferrous Metals Resources by High Pressure Oxygen Leaching Methodology: A Review

Research on Separation and Extraction of Valuable Metals from Complex Non-ferrous Metals Resources by High Pressure Oxygen Leaching Methodology: A Review

Research on Selection and Material Selection of High Pressure Oxygen Valve

Research on Selection and Material Selection of High Pressure Oxygen Valve

The Role of Oxygen Transfer in Oxide Heterostructures on Functional Properties

AbstractA variety of mechanisms are reported to play critical roles in contributing to the high carrier/electron mobility in oxide/SrTiO3 (STO) heterostructures. By using La0.95Sr0.05TiO3 (LSTO) epitaxially grown on different single crystal substrates (such as STO, GdScO3, LaAlO3, (LaAlO3)0.3(Sr2AlTaO6)0.7, and CeO2 buffered STO) as the model systems, the formation of a conducting substrate surface layer (CSSL) on STO substrate is shown at relatively low growth temperature and high oxygen pressure (725 °C, 5 × 10–4 Torr), which contributes to the enhanced conductivity of the LSTO/STO heterostructures. Different from the conventional oxygen vacancy model, this work reveals that the formation of the CSSL occurs when growing an oxide layer (LSTO in this case) on STO, while neither annealing nor the growth of an Au layer alone at the exact same growth condition generates the CSSL in STO. It demonstrates that the oxide layer actively pulls oxygen from STO substrate at given growth conditions, leading to the formation of the CSSL. The observations emphasize the oxygen transfer across film/substrate interface during the synthesis of oxide heterostructures playing a critical role in functional properties.

Forced Solid-State Oxidation Studies of Nifedipine-PVP Amorphous Solid Dispersion.

In the present study, the oxidative degradation behavior of nifedipine (NIF) in amorphous solid dispersions (ASDs) prepared with poly(vinyl pyrrolidone) (PVP) with a short (K30) and a long (K90) chain length was investigated. The ASDs were prepared via dry ball-milling and analyzed using Fourier transform infrared (IR) spectroscopy, X-ray scattering, and differential scanning calorimetry. The ASDs were exposed to accelerated thermal-oxidative conditions using a pressurized oxygen headspace (120 °C for 1 day) and high temperatures at atmospheric pressure (60-120 °C for a period of 42 days). Additionally, solution-state oxidative degradation studies showed that pure NIF degrades to a greater extent than in the presence of PVP. Electronic structure calculations were performed to understand the impact of drug-polymer intermolecular interactions on the autoxidation of drugs. While no drug degradation was observed in freshly prepared ASD samples, alkyl free radicals were detected via electron paramagnetic resonance (EPR) spectroscopy. The free radicals were found to be consumed to a greater extent by PVP K30- than PVP K90-based ASDs upon exposure to high oxygen pressures. This was consistent with the greater solid-state oxidative degradation of NIF observed in ASDs with PVP K30 than with PVP K90. As no drug recrystallization occurred during this study period, the lower glass-transition temperature and presumed greater molecular mobility of PVP K30 and its ASD as compared to the PVP K90 system appear to contribute to the greater drug degradation in PVP-K30-based ASDs. The extent and the rate of oxidative degradation were higher in the case of PVP-K30-based ASD as compared to that in PVP-K90-based ASD, and the overall degradation increased with an increase in temperature. IR spectral analysis of drug-polymer interactions supports the electronic calculations of the oxidation process. We infer that, apart from the initial free radical content, the difference in the extent of drug-polymer intermolecular interactions in ASDs and amorphous stabilization during the forced oxidation experiments contribute to the observed differences in the autoxidative reactivity of the drug in ASDs with different PVP chain lengths. Overall, the chemical degradation of NIF in ASDs with two PVP chain lengths obtained from accelerated solid-state oxidation studies was in qualitative agreement with that obtained from long-term (3 years) storage under ambient conditions. The study highlights the ability of accelerated processes to determine the oxidative degradation behavior of polymeric ASDs and suggests that the polymer chain length could factor into chemical as well as physical stability considerations.

Hyperoxemia in postsurgical sepsis/septic shock patients is associated with reduced mortality

BackgroundDespite growing interest in treatment strategies that limit oxygen exposure in ICU patients, no studies have compared conservative oxygen with standard oxygen in postsurgical patients with sepsis/septic shock, although there are indications that it may improve outcomes. It has been proven that high partial pressure of oxygen in arterial blood (PaO2) reduces the rate of surgical-wound infections and mortality in patients under major surgery. The aim of this study is to examine whether PaO2 is associated with risk of death in adult patients with sepsis/septic shock after major surgery.MethodsWe performed a secondary analysis of a prospective observational study in 454 patients who underwent major surgery admitted into a single ICU. Patients were stratified in two groups whether they had hyperoxemia, defined as PaO2 > 100 mmHg (n = 216), or PaO2 ≤ 100 mmHg (n = 238) at the day of sepsis/septic shock onset according to SEPSIS-3 criteria maintained during 48 h. Primary end-point was 90-day mortality after diagnosis of sepsis. Secondary endpoints were ICU length of stay and time to extubation.ResultsIn patients with PaO2 ≤ 100 mmHg, we found prolonged mechanical ventilation (2 [8] vs. 1 [4] days, p < 0.001), higher ICU stay (8 [13] vs. 5 [9] days, p < 0.001), higher organ dysfunction as assessed by SOFA score (9 [3] vs. 7 [5], p < 0.001), higher prevalence of septic shock (200/238, 84.0% vs 145/216) 67.1%, p < 0.001), and higher 90-day mortality (37.0% [88] vs. 25.5% [55], p = 0.008). Hyperoxemia was associated with higher probability of 90-day survival in a multivariate analysis (OR 0.61, 95%CI: 0.39–0.95, p = 0.029), independent of age, chronic renal failure, procalcitonin levels, and APACHE II score > 19. These findings were confirmed when patients with severe hypoxemia at the time of study inclusion were excluded.ConclusionsOxygenation with a PaO2 above 100 mmHg was independently associated with lower 90-day mortality, shorter ICU stay and intubation time in critically ill postsurgical sepsis/septic shock patients. Our findings open a new venue for designing clinical trials to evaluate the boundaries of PaO2 in postsurgical patients with severe infections.

Structural, electrical, and luminescence properties of (0001) ZnO epitaxial layers grown on c-GaN/sapphire templates by pulsed laser deposition technique

A systematic study of growth, structural, electrical, and luminescence properties of zinc oxide (ZnO) layers grown on c-oriented GaN/sapphire templates by the pulsed laser deposition technique is carried out. A thorough high-resolution x-ray diffraction study reveals that c-ZnO films with high crystalline quality can be grown under certain growth conditions. Screw and edge dislocation densities in these films are found to be as low as 7×108 and 3×1010cm−2, respectively. All layers are found to be unintentionally n-type with ∼1019cm−3 electron concentration and mobility as high as ∼50 cm2 V−1 s−1. Temperature and excitation intensity dependent photoluminescence (PL) studies as functions of the growth conditions are carried out to identify the transition processes behind various luminescence features found in these samples. At low temperatures, PL spectra are marked by sharp neutral donor bound excitonic transitions, their phonon replicas, and two broad luminescence bands at 2.2 and 2.9 eV. These broad bands are attributed to transitions from the (2+/0) oxygen vacancy (VO) and (2+/+/0) zinc-interstitial (Zni) levels, respectively, to the valence band. Thermal energy needed to depopulate these defects is found to be 11 and 385 meV, respectively, for the (2+/0) VO and (2+/+/0) Zni levels. Low temperature PL spectra for the samples grown with relatively high oxygen pressures are featured by the Zn-vacancy (VZn) related neutral acceptor bound excitonic transition, its phonon replicas, and a broad band at 2.75 eV. This band diminishes with increasing temperature and, instead, another broad feature appears at ∼2.1 eV. Our study attributes the 2.75 eV band to transition from the conduction band to (0/−) VZn levels and the 2.1 eV feature to the transition between (−/2−) VZn levels and the valence band. It has been found that all the defect related features can be minimized by adjusting the growth conditions.

The effects of oxygen pressure on the discharge performance of potassium–oxygen batteries

Applying high oxygen pressure drastically improves the discharge performance of potassium-oxygen batteries. High oxygen pressure can also prevent parasitic reactions leading towards K2SO4 and K2CO3 induced by oxygen depletion within the cathode.

Revealing the role of interfacial heterogeneous nucleation in the metastable thin film growth of rare-earth nickelate electronic transition materials.

Although rare-earth nickelates (ReNiO3, Re ≠ La) exhibit abundant electronic phases and widely adjustable metal to insulator electronic transition properties, their practical electronic applications are largely impeded by their intrinsic meta-stability. Apart from elevating the oxygen reaction pressure, heterogeneous nucleation is expected to be an alternative strategy that enables the crystallization of ReNiO3 at low meta-stability. In this work, the respective roles of high oxygen pressure and heterogeneous interface in triggering ReNiO3 thin film growth in the metastable state are revealed. ReNiO3 (Re = Nd, Sm, Eu, Gd and Dy) thin films grown on a LaAlO3 single crystal substrate show effective crystallization at atmospheric pressure without the necessity to apply high oxygen pressure, suggesting that the interfacial bonding between the ReNiO3 and substrates can sufficiently reduce the positive Gibbs formation energy of ReNiO3, which is further verified by the first-principles calculations. Nevertheless, the abrupt electronic transitions only appear in ReNiO3 thin films grown at high oxygen pressure, in which case the oxygen vacancies are effectively eliminated via high oxygen pressure reactions as indicated by near-edge X-ray absorption fine structure (NEXAFS) analysis. This work unveils the synergistic effects of heterogeneous nucleation and high oxygen pressure on the growth of high quality ReNiO3 thin films.

Properties and Modification of Bismuth‐Layered Structure Ferroelectric Materials and Application in Sports

Bismuth‐layered oxides are a very important class of ferroelectric materials. Due to their special structure, they have outstanding features in many aspects, such as high Curie temperature, large spontaneous polarization, polarization stability to temperature, high voltage resistance, low dielectric loss, and excellence. Due to its antifatigue properties, the system is very suitable for applications in nonvolatile random access memory and high‐temperature sensors. The purpose of this paper is to study the application of the performance and modification of bismuth‐layered ferroelectric materials in sports scientific research. Proposed the combination of new materials and sports scientific research projects. This article uses sample analysis and (the comparative experiment method is a method to compare the experimental group and the control group to illustrate the superiority of the experiment) comparative experiment methods, sets up an experimental group and a control group, summarizes the algorithm rules through the study of the microscopic properties of nanomaterials, and designs a numerical simulation program. The experimental results in this article show that after receiving hyperbaric oxygen recovery in the first week, the heart rate of the experimental group subjects has a significant change, which is significantly lower than the initial value (p &lt; 0.05), from 58.0 to 53.0, The higher pressure oxygen had a very significant drop before recovery, from 62.9 to 53.0. In the second week and the third week, the heart rate index decreased significantly after 1 hour of hyperbaric oxygen recovery (p &lt; 0.01), from 54.3 to 49.3 and 56.1 to 52.4, respectively. After the fourth week of intensity training, the heart rate increased significantly from the initial value (p &lt; 0.05), from 49.6 to 55.2. After 1 hour of hyperbaric oxygen recovery, there was a significant decrease compared with before the hyperbaric oxygen recovery (p &lt; 0.05), dropped from 55.2 to 53.1. Illustrate the success of the experimental results. It also completed the subject of interaction and combination of the performance and modification of bismuth‐layered ferroelectric materials in sports scientific research.

High Pressure and Ti Promote Oxygen Vacancies in Perovskites for Enhanced Thermoelectric Performance

High Pressure and Ti Promote Oxygen Vacancies in Perovskites for Enhanced Thermoelectric Performance

Extremely Overdoped Superconducting Cuprates via High Pressure Oxygenation Methods

Within the cuprate constellation, one fixed star has been the superconducting dome in the quantum phase diagram of transition temperature vs. the excess charge on the Cu in the CuO2-planes, p, resulting from O-doping or cation substitution. However, a more extensive search of the literature shows that the loss of the superconductivity in favor of a normal Fermi liquid on the overdoped side should not be assumed. Many experimental results from cuprates prepared by high-pressure oxygenation show Tc converging to a fixed value or continuing to slowly increase past the upper limit of the dome of p = 0.26–0.27, up to the maximum amounts of excess oxygen corresponding to p values of 0.3 to &gt; 0.6. These reports have been met with disinterest or disregard. Our review shows that dome-breaking trends for Tc are, in fact, the result of careful, accurate experimental work on a large number of compounds. This behavior most likely mandates a revision of the theoretical basis for high-temperature superconductivity. That excess O atoms located in specific, metastable sites in the crystal, attainable only with extreme O chemical activity under HPO conditions, cause such a radical extension of the superconductivity points to a much more substantial role for the lattice in terms of internal chemistry and bonding.

Medical gas pipeline system as a limiting factor for hospital oxygen supply during COVID-19 outbreak.

Medical gas pipeline system as a limiting factor for hospital oxygen supply during COVID-19 outbreak.