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

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

The HIsmelt process uses pulverized coal and iron ore as raw materials, eliminating the need for coking and iron ore lumping compared to traditional blast furnace ironmaking processes, and significantly reducing CO2 and other pollutants emissions. However, as a new ironmaking process, the flow field, heat transfer, and combustion influencing factors of the main reactor are not resolved. Therefore, in this study, based on the consideration of fluid mechanics, heat conduction, and combustion reaction, a two-dimensional mathematical model was developed for the upper space of SRV (smelting reduction vessel), the main reactor of the HIsmelt ironmaking process, based on actual production data. The effects of hot air oxygen content and daily iron production on the velocity field, temperature field, and CO2 content field inside the SRV were investigated. The results show that as the oxygen content of hot air increases, the central airflow in the furnace develops downward, the gas temperature rises gradually, and the CO2 mass fraction generally shows a rising trend. When the daily output of iron increases, the velocity of airflow in the furnace decreases significantly, the gyratory zone moves upward; the high-temperature distribution zone in the furnace contracts; and the CO2 mass fraction decreases. [ABSTRACT FROM AUTHOR]

In the presence of molecular oxygen, edible oils can be oxidized to form a multitude of α,β-unsaturated carbonyl products collectively called 'lipid-derived electrophiles'. These molecules affect the taste of fat-containing foods but also act as electrophiles by covalently binding to protein amines/thiols and DNA nucleotides. The chemical modification of proteins by lipid-derived electrophiles appears to play an important role in human health, but the quantification of this diverse class of compounds remains a challenge. In this study, we describe a method capable of measuring the relative content of α,β-unsaturated carbonyls in food containing edible oils by using a "turn-on" fluorescent probe. The detection of electrophiles is based on a pre-fluorescent probe, 7-mercapto-4-methyl-coumarin (C-SH). The fluorescence of C-SH increases after nucleophilic addition to electrophilic lipid oxidation products. Since different lipid-derived electrophiles will react at a different rate with our fluorescent probe, we expressed the probe's response against a standard electrophile: trans-2-nonenal. In this assay, electrophiles which react more quickly will have a more dominant weight in the measurements carried out. Using this analytical technique, we can compare electrophilic content in French fries from several restaurants, and find they have lower amounts of lipid-derived electrophiles versus frozen fries baked at home. We also demonstrate that potato chips sealed in a reduced oxygen atmosphere will have a low 'electrophilic content' that increases over time, whereas chips in oxygen-permeable packaging initially have a higher 'electrophilic content' that does not increase as much over time. The relative ease of fluorescence measurements using microplate readers coupled with a simple oil extraction protocol should allow this method to quantify 'electrophilic content' in several food sources. [ABSTRACT FROM AUTHOR]

ABSTRACT This study explores the controlled synthesis of a novel Fe3O4@C magnetic nanocomposite derived from FeBTC metal–organic framework (MOF) and its application as an efficient adsorbent for the removal of rhodamine dye from wastewater. The FeBTC MOF was first synthesized and then thermally decomposed in a controlled oxygen atmosphere at 375°C (1 h) to form the Fe3O4@C nanocomposite with a magnetic Fe3O4 core embedded in a porous carbon matrix. A comprehensive characterization of the nanocomposite was performed using x‐ray diffraction (XRD), transmission electron microscopy (TEM), and x‐ray photoelectron spectroscopy (XPS) to confirm the successful formation and to evaluate its structural and morphological properties. The morphological investigation revealed that the particles of Fe3O4 had a spherical shape with diameter of 10–15 nm. The carbon coating appeared as a thin amorphous layer surrounding the Fe3O4 nanoparticles. The adsorption capacity of Fe3O4@C for rhodamine B (RhB) dye was assessed under various conditions, including different pH values, contact times, initial dye concentrations, and temperatures. Complete dye removal was attained in 45 min using 50 mg of the nanocomposite and 50 mL of 5.0 ppm RhB at the optimum pH of 9.1. Under the same experimental conditions, the highest adsorption capacity of 13.0 mg/g was obtained, but using 15.0 mg of the nanocomposite. Fe3O4@C nanocomposite exhibits high adsorption efficiency, with a maximum removal capacity of 100%, which is clearly superior to many conventional adsorbents. This performance can be attributed to the synergistic effects of the magnetic Fe3O4 and the large surface area of the carbon matrix. Kinetic models were employed to understand the adsorption mechanism. The adsorption kinetics followed a pseudo‐second‐order model. The reusability of the adsorbent was tested over multiple cycles and showed a minimal loss of performance (drops to 93.0% after five removal cycles). The study demonstrates that the Fe3O4@C nanocomposite is a promising candidate for the effective removal of organic dyes from wastewater, offering potential benefits for environmental remediation and sustainable water management. [ABSTRACT FROM AUTHOR]

A high entropy carbide (TaNbTiV)C was fabricated via spark plasma sintering of high entropy powders that were prepared using a molten salt method. The as-fabricated high entropy carbide was then investigated for its high-temperature oxidation behavior at 850 °C, under atmospheres with three different oxygen contents (20 vol%, 40 vol%, and 60 vol%). After the high-temperature oxidation process, the main phases observed in all the specimens were incompletely oxidized phase (Nb x Ti 1-x)C y O 2-y and oxides (Nb 0.5 Ta 0.5) 2 O 5 , TiO 2 , and Nb 2 O 5. Importantly, the thickness of the oxide layer initially increased and then decreased as the oxygen content increased. When the oxygen content reached 40 vol%, the ceramic displayed severe oxidation behavior with observed thicker of the oxide layer, as well as numerous pores and cracks in the oxide layer. This work provides new insights into the oxidation behavior of high entropy carbides. [ABSTRACT FROM AUTHOR]

The rational design of MgO nanomaterials with rich oxygen vacancies has garnered significant attention. However, the influence of oxygen vacancies and alkalinity on the generation and stability of active oxygen, particularly regarding the antibacterial activity of MgO nanomaterials, remains uncertain. In this work, the defective MgO nanoplates with adjustable oxygen vacancy and alkalinity were successfully designed by thermal treatment in different atmospheres (air, vacuum, and N 2). MgO nanoplates calcined in N 2 atmosphere exhibited superior antibacterial activity against Escherichia coli (ATCC 25922), reducing colony counts from 571.5 to 53.5 CFU/mL at 750 μg/mL compared with MgO nanoplates calcined in air. At a low concentration (100 μg/mL), MgO nanoplates calcined in N 2 atmosphere exhibited remarkable antibacterial performance, achieving a colony survival ratio of only 6.8 %. This enhanced performance was correlated with a higher oxygen vacancy (O A) content (51.3 %) in MgO nanoplates calcined in N 2 compared to those calcined in air (26.5 %). Advanced characterization techniques and alkalinity measurements revealed that calcination in a N 2 atmosphere promoted oxygen vacancy formation on the MgO surface, accelerated MgO surface hydrolysis owing to oxygen vacancies, and increased OH− production. Consequently, this process enhances the participation of adsorbed oxygen in surface reaction, leading to the increased generation and stability of active oxygen in an alkaline environment. These findings provide valuable insights into the design of oxygen vacancies and offer a potential approach for constructing highly antibacterial nanomaterials. Such materials could find applications in personal protection and public health. [ABSTRACT FROM AUTHOR]

Limited oxygen (hypoxia) in solid tumors poses a challenge to successful immunotherapy with natural killer (NK) cells. NK cells have impaired cytotoxicity when cultured in hypoxia (1% oxygen) but not physiologic (>5%) or atmospheric oxygen (20%). We found that changes to cytotoxicity were regulated at the transcriptional level and accompanied by metabolic dysregulation. Dosing with interleukin-15 (IL-15) enhanced NK cell cytotoxicity in hypoxia, but preactivation with feeder cells bearing IL-21 and 4-1BBL was even better. Preactivation resulted in less perturbed metabolism in hypoxia; greater resistance to oxidative stress; and no hypoxia-induced loss of transcription factors (T-bet and Eomes), activating receptors, adhesion molecules (CD2), and cytotoxic proteins (TRAIL and FasL). There remained a deficit in CD122/IL-2Rβ when exposed to hypoxia, which affected IL-15 signaling. However, tri-specific killer engager molecules that deliver IL-15 in the context of anti-CD16/FcγRIII were able to bypass this deficit, enhancing cytotoxicity of both fresh and preactivated NK cells in hypoxia. [ABSTRACT FROM AUTHOR]

Quinones are one of the most commonly used drugs for cancer treatment. Combinations of quinoid compounds and other oxidation inducers with flaxseed oil (FO), which is rich in omega‐3 alpha‐linolenic acid, show promise for improving the efficacy of antitumor drugs. Effects of benzo‐, naphtho‐, and anthraquinones, as well as metronidazole and a number of nitro‐1,2,4‐triazoles on the oxidative stability of FO, were studied. To this end, kinetic curves were obtained showing the accumulation of hydroperoxides in FO during storage at 37°C with free access to atmospheric oxygen. The calculated oxidation induction period demonstrates that the majority of the tested quinones intensify the oxidation of FO. Pro‐oxidant activity is maximum for 1,4‐benzoquinone and significantly decreases (p < 0.05) when various substituents are introduced into its ring. A noticeable increase in the concentration of hydroperoxides and the rate of oxidation at the initial stage of the oxidation process is characteristic for 1,4‐benzoquinone and its derivatives. Additives of 1,4‐naphthoquinone and 2‐hydroxy‐1,4‐naphthoquinone (lawsone) do not affect the oxidative stability of FO, while 5‐hydroxy‐1,4‐naphthoquinone (juglone) and 4,6‐di‐tert‐butyl‐1,2‐benzoquinone effectively inhibit the oxidation of FO. The oxidation of FO lipids is accelerated by all investigated nitroazoles; however, 1‐methyl‐3,5‐dinitro‐1,2,4‐triazole has the highest pro‐oxidant activity. Practical Applications: The results of this study may be useful in the development of new methods of antitumor therapy using omega‐3 polyunsaturated substrates in combination with quinoid and nitrotriazole cytostatics. The data obtained can also be used in the development of oxidation‐stable foods based on flaxseed oil, as well as in the production of resins, drying oils, varnishes, paints, and other materials. [ABSTRACT FROM AUTHOR]

Most exoplanets with a few Earth radii are more inflated than bare-rock planets with the same mass, indicating a substantial volatile amount. Neither the origin of the volatiles nor the planet's bulk composition can be constrained from the mass–radius relation alone, and the spectral characterization of their atmospheres is needed to solve this degeneracy. Previous studies showed that chemical interaction between accreted volatile and possible molten rocky surface (i.e., magma ocean) can greatly affect the atmospheric composition. However, a variety in the atmospheric compositions of such planets with different properties remains elusive. In this work, we examine the dependence of atmospheric H, O, and C on planetary parameters (atmospheric thickness, planetary mass, equilibrium temperature, and magma properties such as redox state) assuming nebula gas accretion on an Earth-like core, using an atmosphere-magma chemical equilibrium model. Consistent with previous work, we show that atmospheric H2O fraction on a fully molten rocky interior with an Earth-like redox state is on the order of 10−2–10−1 regardless of other planetary parameters. Despite the solubility difference between H- and C-bearing species, C/H increases only a few times above the nebula value except for atmospheric pressure ≲1000 bar and H2O fraction ≳10%. This results in a negative O/H–C/O trend and depleted C/O below one-tenth of the nebula gas value under an oxidized atmosphere, which could provide a piece of evidence of rocky interior and endogenic water. We also highlight the importance of constraints on the high-pressure material properties for interpreting the magma–atmospheric interaction of inflated planets. [ABSTRACT FROM AUTHOR]

As an electrochemical device that converts the chemical energy of fuel directly into electrical energy, the fuel cell is a new alternative technology that uses fuel from renewable sources and generates power for sustainable development and energy security. Among various types of fuel cells, the direct carbon fuel cell (DCFC) has higher efficiency because carbon fuel has higher energy density than liquid or gas fuel. However, the current development of DCFCs is still limited by the sluggish activity of the cathode reaction. In this study, a new composite cathode made of Gd0.2Ce0.8O1.9 (GDC) and SrFe1−xTixO3–δ (SFT) is developed for a Nicotiana tabacum-derived carbon fuel-based DCFC. The structural, optical, and electrochemical properties of the materials are systematically evaluated. X-ray diffraction analysis results show a cubic structure of GDC and cubic perovskite phase of SFT in the sample, with crystallite sizes of 37 and 15 nm, respectively. Ultraviolet–visible spectroscopy reveals an indirect band gap which exhibits a red shift. Fourier transform infrared spectroscopy confirms the presence of Ce–O, Sr–Ti–O, and Fe–O functional groups in all the samples. Scanning electron microscopy analysis shows the morphology and particle size of the materials. The sample Gd0.2Ce0.8O2-δ–SrFe0.96Ti0.04O1.9 exhibits the highest electrical conductivity of 4.96 S cm−1 in an oxygen atmosphere at 600 °C and a higher power density of 40 mW cm−2 at 600 °C compared to other samples using Nicotiana tabacum carbon fuel. These findings indicate that the developed composite cathode is an efficient cathode for low-temperature DCFCs. [ABSTRACT FROM AUTHOR]

Pyridinic nitrogen vacancy in carbon nitride for photo-self Fenton-like purification of organic contaminants. [Display omitted] • Carbon nitride with pyridinic nitrogen vacancy was successfully prepared. • Pyridinic nitrogen vacancy promotes charge transfer and activating O 2 into H 2 O 2. • Pyridinic nitrogen vacancy accelerates carbon nitride to adsorb organic contaminants. • Photo-self Fenton-like reaction for photocatalytic degradation of organics. This work reports a carbon nitride with pyridinic nitrogen-vacancy (N 2C V-CN), which purifies organic contaminants via an in-situ photo-self Fenton-like reaction. Experiments and calculations demonstrated that the nitrogen-vacancy induces lone-paired (LP) and symmetry-unpaired electrons, promoting the formation of low-energy LP-π hybridized orbitals and helping to overcome the pairing energy required for oxygen to accept electrons. Furthermore, the nitrogen-vacancy accelerates film and intra-particle diffusion rates of organic contaminants on N 2C V-CN, creating beneficial conditions for reactive oxide species to mineralize organic contaminants. Under sunlight and atmospheric oxygen, a photo-self Fenton-like reaction involving proton-coupled electron transfer occurred on the surface of N 2C V-CN. Furthermore, by integrating photocatalysis with flocculation, about 99.1 % suspended substance, 45.5 % chemical oxygen demand, and 38.4 % biological oxygen demand were reduced from polluted river-water. Constructing N 2C V-CN and understanding its crucial role offer theoretical and methodological insights into the in-situ purification of contaminated water bodies. [ABSTRACT FROM AUTHOR]

In order to facilitate the dissolution of these insoluble nuclear debris from the Fukushima Daiichi NPS accident, it is necessary to investigate methods of pulverizing them to increase their surface area. For uranium and zirconium oxides in nuclear fuel debris, we proposed a pretreatment method using a redox method to achieve powdering. In this study, the simulated nuclear fuel debris pellets with uranium-zirconium ratio 9:1 and 1:1, and the pellet containing U, Zr, Fe, Gd, Nd and Si (65%:10%:10%:5%:5%:5%) were subjected to heating oxidation experiments in an oxygen atmosphere and reduction experiments after oxidation. The feasibility of pulverizing uranium-zirconium solid after heating and oxidation was demonstrated. And the product of the powder after redox reaction, uranium dioxide to triuranium octoxide was confirmed by XRD. Thus increasing the surface area required for dissolution or chemical conversion to soluble compounds can be expected. [ABSTRACT FROM AUTHOR]

Steel slag-based glass ceramic for thermal energy storage was first fabricated by quenching method, and then their high temperature corrosion behavior in the eutectic carbonates and related mechanism have been investigated using X-ray diffraction，Raman spectroscopy and scanning electron microscope techniques. The results show that holding time has a significant influence on the corrosion layer thickness at 800oC. As the holding time was extended, the thickness of the corrosion layer with obvious cracks tended to increase. Further EDS analyses disclosed that the divided corrosive layers along the extended directions of the cracks should be similar in both the compositions and microstructure. Based on these observations, the possible corrosion mechanism was discussed after defining phase structure of nonstoichiometric (Fe 0.35 Al 0.20 Mg 0.44) Ca 0.96 (Fe 0.08 Si 0.70 Al 0.20) 2 O 6.12 as a combined system of CaMgSi 2 O 6 (Di)-CaFe3+AlSiO 6 (Es)-CaAl 2 Si 2 O 8 (An). Oxygen offered by the molten carbonates salt is regarded to play a critical role in the corrosion process. In an atmosphere rich in oxygen, both Na+ and K+ ions diffused into the diopside can replace Ca2+ and Mg2+, etc. resulting in polyhedral structural reorganization for electrical neutrality. On the other hand, the bonding stability of the cation-oxygen bonds in diopside was proved to be weaker than that in single oxides. These two aspects contribute to the continuous dissolution of Ca2+ and Mg2+, etc. in the molten carbonates salt. [ABSTRACT FROM AUTHOR]

Introduction: Hemorrhagic cystitis (HC) is a common complication after allogeneic hematopoietic stem cell transplantation (HSCT), characterized by inflammation and bleeding of the bladder. Hyperbaric oxygen therapy (HBOT) has been shown to be effective in the treatment of radiation-induced HC. However, the optimal treatment for HC after allogeneic HSCT has not yet been established. Furthermore, limited research has been conducted on the use of HBOT in this setting. This study aimed to evaluate the effectiveness and safety of HBOT in patients with late-onset HC after allogeneic HSCT. Methods: Twenty-five-year (1998–2022) retrospective analysis performed in all consecutive patients with confirmed late-onset HC after allogeneic HSCT treated with HBOT at two centers in Portugal. Medical records were reviewed for clinical and laboratory features, primary indications for allogeneic HSCT, conditioning regimen, and treatment strategies for HC. Patients received 100% oxygen at 2.1–2.5 atmosphere absolute pressure (ATA) for 70–90-minute periods, once daily, five times per week. Complete clinical response was defined as the absence of macroscopic hematuria sustained for at least 2 weeks, and partial response was described as a downgrading in the severity of HC. Statistical significance was considered for values of p < 0.05. Results: The sample included 61 patients with a mean age of 28.0 (SD 14.2) years, 33 males. Complete response was achieved in 72.1% (n = 44) of patients and partial response in 14.8% (n = 9). Concerning patients with a complete response, the median number of HBOT sessions was 15.5 sessions (IQR 10.0-26.8). Patients treated with 10 or more sessions of HBOT had a higher rate of complete or partial response (OR 12.5, 95%CI 1.9–83.2, p-value < 0.05). There was no response in 8 (13.1%) patients, and 6 interrupted the treatments early. Only 2 patients suspended the HBOT due to a lack of clinical benefit. Conclusion: Our study supports using of HBOT as an adjunctive treatment for late-onset HC after allogeneic HSCT. Furthermore, 10 or more HBOT sessions delivered seem to impact the rate of HC resolution. Prospective, randomized, and well-controlled trials are needed to establish HBOT's definitive efficacy and safety. [ABSTRACT FROM AUTHOR]

Hepatocytes-like cells (HLC) derived from human induced pluripotent stem cells show great promise for cell-based liver therapies and disease modelling. However, their application is currently hindered by the low production yields of existing protocols. We aim to develop a bioprocess able to generate high numbers of HLC. We used stirred-tank bioreactors with a rational control of dissolved oxygen concentration (DO) for the optimization of HLC production as 3D aggregates. We evaluated the impact of controlling DO at physiological levels (4%O2) during hepatic progenitors' stage on cell proliferation and differentiation efficiency. Whole transcriptome analysis and biochemical assays were performed to provide a detailed characterization of HLC quality attributes. When DO was controlled at 4%O2 during the hepatic progenitors' stage, cells presented an upregulation of genes associated with hypoxia-inducible factor pathway and a downregulation of oxidative stress genes. This condition promoted higher HLC production (maximum cell concentration: 2 × 106 cell/mL) and improved differentiation efficiencies (80% Albumin-positive cells) when compared to the bioreactor operated under atmospheric oxygen levels (21%O2, 0.6 × 106 cell/mL, 43% Albumin positive cells). These HLC exhibited functional characteristics of hepatocytes: capacity to metabolize drugs, ability to synthesize hepatic metabolites, and inducible cytochrome P450 activity. Bioprocess robustness was confirmed with HLC derived from different donors, including a primary hyperoxaluria type 1 (PH1) patient. The generated PH1.HLC showed metabolic features of PH1 disease with higher secretion of oxalate compared with HLC generated from healthy individuals. This work reports a reproducible bioprocess, that shows the importance of controlling DO at physiological levels to increase HLC production, and the HLC capability to display PH1 disease features. [ABSTRACT FROM AUTHOR]

The growth of NiO epitaxial thin films on (‐201) β‐Ga2O3 by mist chemical vapor deposition (CVD) and the effects of carrier gas selection (N2 and O2) and substrate preannealing treatment on the structural and morphological properties on the grown thin films are explored. X‐ray diffraction analysis reveals successful epitaxial growth with the orientation relationship (111) NiO [0‐11] || (‐201) β‐Ga2O3 [010]. As a carrier gas, O2 results in single‐domain NiO films while N2 leads to the formation of rotational domains. Atomic force microscopy and field‐emission scanning electron microscopy confirm the lateral growth of NiO films, thus highlighting the importance of substrate preannealing at 1200 °C in oxygen atmosphere to obtain flat, high‐quality films. The results demonstrate that the method of mist CVD combined with appropriate substrate preparation and carrier gas selection is effective for the growth of high‐quality NiO/β‐Ga2O3 heterostructures. This achievement opens new possibilities for the development of wide‐bandgap p–n heterojunctions, potentially advancing the field of high‐power oxide‐based electronic devices. [ABSTRACT FROM AUTHOR]

Early biofilm formation could be inhibited by applying a thin biocompatible copper coating to reduce periprosthetic infections. In this study, we deposited crystalline Cu-doped TiO2 films using one-step DC magnetron sputtering in an oxygen atmosphere on a biased Ti6Al4V alloy without external heating. The bias voltage varied from −25 V to −100 V, and the resultant substrate temperature was measured. The deposited coatings were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), microhardness, scratch and hydrophilicity tests, potentiodynamic polarization measurements, and antibacterial assays against S. aureus and E. coli. The findings demonstrated that when a higher negative bias is applied, the substrate temperature drops, and the anatase to rutile transformation is initiated without indicating obvious Cu-containing phases. The SEM images of the films showed spherical agglomerates with homogeneously distributed Cu with decreasing Cu content as the bias value increased. Higher bias results in the grain refinement of the thinning coatings with more lattice microstrain and more defects, together with an increase in water contact angles and hardness values. Samples biased at −75 V exhibited the highest adhesive strength between coatings and substrate, whereas the specimen biased at −50 V demonstrated higher corrosion resistance. Cu-containing TiO2 coatings with pure anatase phase composition and Cu concentrations of 2.62 wt.% demonstrated excellent bactericidal activity against both S. aureus and E. coli. The layers containing 2.34 wt.% Cu exhibited very good antibacterial properties against S. aureus, only. According to these findings, the produced copper-doped TiO2 coatings have high bactericidal qualities in vitro and may be used to prepare orthopaedic and dental implants in the future. [ABSTRACT FROM AUTHOR]

Airbreathing catfish are stenohaline freshwater fish capable of withstanding various environmental conditions and farming practices, including breathing atmospheric oxygen. This unique ability has enabled them to thrive in semi-terrestrial habitats. However, the genomic mechanisms underlying their adaptation to adverse ecological environments remain largely unexplored, primarily due to the limited availability of high-quality genomic resources. Here, we present a haplotype-resolved and near telomere-to-telomere (T2T) genome assembly of the African catfish (Clarias gariepinus), utilizing Oxford Nanopore, PacBio HiFi, Illumina and Hi-C sequencing technologies. The primary assembly spans 969.62 Mb with only 47 contigs, achieving a contig N50 of 33.71 Mb. Terminal telomeric signals were detected in 22 of 47 contigs, suggesting T2T assembled chromosomes. BUSCO analysis confirmed gene space completeness of 99% against the Actinopterygii dataset, highlighting the high quality of the assembly. Genome annotation identified 25,655 protein-coding genes and estimated 43.94% genome-wide repetitive elements. This data provides valuable genomic resources to advance aquaculture practices and to explore the genomic underpinnings of the ecological resilience of airbreathing catfish and related teleosts. [ABSTRACT FROM AUTHOR]

The effect of cyclization degree of nitrogen thermal pretreatment on the radial structure difference of polyacrylonitrile(PAN) oxide fibers is explored. In this paper, PAN fibers were isothermally heated in nitrogen at 170°C, 190°C and 210°C for 0, 10, 20, 30, 40, and 50 min, respectively, so as to obtain pre‐treated fibers with cyclization degrees of 0%, 19.96%, 35.18%, 38.92%, 42.80%, and 53.12%, respectively. The pre‐treated fibers were further stabilized in an oxygen atmosphere. The scanning results show that the radial structure difference of oxide fibers first decreases and then increases with cyclization degree increasing. Through FTIR, SEM and Raman characterization, it is found that this phenomenon is mainly related to the influence of nitrogen thermal pretreatment on oxygen diffusion. Therefore, to improve the thermal stability efficiency of PAN fibers by means of nitrogen thermal pre‐treatment, it is necessary to control the degree of cyclisation, and the appropriate degree of cyclisation in the present work is about 35%. [ABSTRACT FROM AUTHOR]

The safe disposal of large irradiated cation exchange resin waste in nuclear power plant has drawn worldwide attention. The kinetic characteristics and product characteristics of the simulated spent cation exchange resin in the pyrolysis and gasification were evaluated based on thermogravimetric analysis as well as TG-FTIR and TG-GC/MS. The temperature ranges at different decomposition stages of the resins were determined. In nitrogen atmosphere, the metal nuclides would hinder the reaction of waste resin in the first stage and promote the reaction in the second stage. The second-order reaction model was the best one to describe the kinetic mechanism in the first and second stages of the spent resins in different atmospheres, while Mample Power model (n = 1) and two-dimensional shrinking cylinder model were for the third gasification stage of the waste resins in 10 % oxygen atmosphere and 10 % steam atmosphere, respectively. The average mass loss ratio of the waste resin in 10 % oxygen atmosphere almost reached to 90 % that was higher than in 10 % steam atmosphere (80 %) and much higher than in nitrogen atmosphere (55 %). The initial reaction temperature in the third stage in 10 % oxygen was about 100 °C earlier than that in 10 % steam atmosphere, indicating that the sulfur bond would easily break due to the strong oxidization action of the oxygen. In the nitrogen atmosphere, the sulfur bond broke at 700 °C, which would lead to low mass loss ratio of the waste resin since the copolymer matrix is difficult to decompose. This work could supply basic data for the pyrolysis and gasification treatment of irradiated spent cation exchange resin in nuclear power plant. [ABSTRACT FROM AUTHOR]

Using the radio frequency magnetron sputtering process, NaNbO3-based antiferroelectric thin films were obtained on Pt(111)/Ti/SiO2/Si substrates. The effects of annealing temperature on the phase structure, dielectric properties, ferroelectric properties, and energy storage properties of the thin films were studied. As the annealing temperature increased, the crystallinity and film quality of the thin films improved. Moreover, oxygen vacancies were effectively suppressed, which is beneficial for the thin film to obtain a higher dielectric constant, a larger saturation polarization, and a smaller residual polarization intensity. The NaNbO3-based thin film has a higher energy storage density, power density and efficiency (Wrec = 3.6 J/cm3, Pd =200.8 kW/cm3, η = 68.31%) at an annealing temperature of 600 ℃. The observed phenomenon could be attributed to higher breakdown field strength and polarization difference resulting from the appropriate annealing temperature and the presence of lower oxygen vacancies under pure oxygen atmosphere. The wonderful property of the NaNbO3-based thin film indicates that it will have the potential to be applied in a wide range of contexts within the sphere of energy storage. [ABSTRACT FROM AUTHOR]

In order to evaluate the increase in the flexural strength of a 3D braided C/SiC composite comprised with a thin pyrolytic carbon (PyC) interlayer (TI C/SiC) under a load of 60 MPa with an amplitude of ±20 MPa at an oxygen partial pressure of 8000 Pa, the effect of temperature, oxidation and stress value on the length change in the sample, fracture behavior, residual flexural strength and fracture morphology were studied up to 1500 °C. It was found that the gauge length change behaviors of the material are related to (i) the positive damage of the thin interlayer and (ii) to the negative damage of the C phase. The most serious damage of TI C/SiC under 60 ± 20 MPa occurs in an oxygen partial pressure of 17,000 Pa at 1300 °C. When the oxygen partial pressure and/or the temperature are reduced, the positive C phase damage is relieved. In the case that the oxygen partial pressure, temperature and stress increase, the negative C phase damage is facilitated. The oxidation mechanism of the C phase is controlled by the inward diffusion of oxygen from the sample surface to the center; however, a higher stress is considered to change the oxygen diffusion mechanism by increasing the reaction of the C phase, with oxygen causing a widening of microcracks. [ABSTRACT FROM AUTHOR]

Utilization of industrial by-products to develop novel value-added materials while mitigating their environmental impact is a crucial issue. Fly ash (FA) microparticles are a common component of power plant waste. This work aims to investigate the impact of varying concentrations of neat/silver-coated FA on the morphology and thermal properties of styrene-butadiene-styrene/FA composites. Composite materials based on styrene-butadiene styrene triblock copolymer (SBS) with various volume fractions of as-received and silver-coated FA were prepared using a solution mixing method. Silver-coated cenosphere particles were prepared using an electroless plating method. Scanning electron microscopy and optical microscopy showed that the solution mixing method obtains composite materials characterized by uniform dispersion of filler without large particle aggregates and predominantly unbroken cenospheres. The tensile strength of the composite with 10% of both as-received and silver-coated fly ash remains at the level of the unfilled SBS sample. However, at higher filler concentrations (20% and 30%), a decrease in strength by 27% and 42% respectively is observed, possibly due to the agglomeration of FA, which leads to a poorer interface and dispersion at higher filler weights. Additionally, thermal analysis in an oxygen atmosphere showed that the introduction of both as-received and metallized cenospheres in the same quantity increased the thermal stability of the tested composition. The temperatures at 5% mass loss of SBS/FA composites were on average 70°C higher than those of the original SBS. [ABSTRACT FROM AUTHOR]

Carbonate‐associated sulfate (CAS) δ34S values (δ34SCAS) are generally assumed to reflect S isotopic composition of paleo‐seawater and have been extensively used to reconstruct secular variations in seawater sulfate concentrations during the geological past. However, it has often been documented that δ34SCAS records are incompatible with seawater sulfur isotopes (20.9 ± 0.1%, 2σ) determined from other archives, such as sulfate evaporites and barite (both of which may also display inconsistencies). A possible explanation for this discrepancy is that δ34SCAS values can be easily altered by atmospheric sulfate and sulfide re‐oxidation. However, the specific influence of biological factors (vital effects, common in biogenic carbonates) on CAS S isotopic composition remains unresolved, particularly at microscale levels. To elucidate these effects on δ34SCAS, S isotopic profiles were analyzed across two skeletal transects of two modern deep‐sea corals (gorgonia) using a novel secondary‐ion mass spectrometry method. Strong S isotopic fractionation was observed in calcitic skeletons from the most 34S‐depleted center (δ34S = ∼19‰), increasing outward to a relatively constant 22.5‰ in gorgonia sp. coral and 21.6‰ in bamboo coral, suggesting that vital effects are much larger than previous estimated (∼±1‰ fractionation from seawater). Oxygen isotopic and Mg, S, O elemental compositions, and Raman spectral and crystal morphological features indicate that processes such as pH control, Rayleigh fractionation, and organic effects are precluded as causes of such fractionation. Instead, vital effects associated with kinetic processes related to surface entrapment seem plausible as controls on S isotopic fractionations in the coral. This novel method is significant for gaining insights into vital effects, assessing the reliability of biogenic carbonates as high‐resolution environmental archives of S isotopes, and understanding the fundamental mechanisms governing biomineralization. Plain Language Summary: The δ34S values of carbonate‐associated sulfate (CAS) serve as crucial indicators of past environmental conditions, providing insights into historical variations in seawater sulfate and atmospheric oxygen levels. It is commonly assumed that δ34SCAS closely reflects seawater sulfate, except for severely altered samples. However, analysis of S isotopic profiles across two skeletal transects of modern calcitic deep‐sea corals (gorgonia sp. coral and bamboo coral) using a newly developed in situ method based on secondary‐ion mass spectrometry, reveals significant isotopic fractionation. The most 34S‐depleted center (δ34S = ∼19‰) increases outward to a relatively constant value of 22.5‰ for gorgonia sp. coral and 21.6‰ for bamboo coral. These findings suggest that vital effects play a notable role in δ34SCAS fractionation, challenging the previous consensus of ∼±1‰. Further investigation, incorporating multiple indices and skeletal δ18O, indicates that vital effects associated with kinetic processes related to surface entrapment contribute to this fractionation. These insights shed light on the processes driving S–O isotopic fractionation in biogenic carbonates, bolstering their utility in reconstructing paleo‐oceanographic conditions. Key Points: Development of in situ carbonate S isotopic analysis using secondary‐ion mass spectrometryCommonly observed anomalous low δ34S and δ18O values in the axial skeleton of deep‐sea gorgonia coralsContribution of kinetic‐associated vital effects to significant Carbonate‐associated sulfate sulfur isotopic fractionation, supported by multiple geochemical indices [ABSTRACT FROM AUTHOR]

This article presents the results of a thermodynamic analysis of the oxidation soda conversion reactions of minerals in ilmenite concentrates in the temperature range of 373–2273 K. The thermodynamic parameters of pseudorutile, pseudobrukite, and the new minerals, zhikinite and spessartine, were calculated for the first time. It has been established that the most important criterion relating to the stability of titanium minerals and related elements, as well as the reaction properties of the structural oxides of metals and silicon, is their degree of oxidation. Oxides of silicon (IV) and manganese have the best reactivity in solid-phase oxidizing alkaline environments (VI). Modeling this process scientifically substantiates the mechanism involved in the destruction of minerals in ilmenite concentrates in the low-temperature region in the presence of atmospheric oxygen and sodium oxide of soda ash, which are decomposed through the absorption of heat and the evaporation of moisture during the dehydration of hydrated minerals of iron and manganese and the dehydration of the soda–ilmenite batch. Tests conducted during pilot metallurgical production at the Institute of Metallurgy and Enrichment (PMP of JSC) confirmed the feasibility of processing high-chromium and siliceous rutile leucoxene ilmenite concentrates, which are unsuitable for traditional pyro- and hydro-metallurgical enrichment methods, through single-stage oxidation soda roasting, followed by the leaching of easily soluble sodium salts of iron and associated impurities with water and a dilute hydrochloric acid solution. The proposed energy-saving method ensures the production of high-purity (>98%) synthetic rutile while eliminating the formation of strong deposits on the lining of roasting units. [ABSTRACT FROM AUTHOR]

Using first-principles density functional theory (DFT) calculations and ab initio molecular dynamics (AIMD) simulations, we performed this study on the phase stability, the intrinsic redox stability, and the Li+ conductivity of Li10GexMo1−xP2S12 (x = 0~1) superionic conductors. Molybdenum (Mo) is expected to replace expensive germanium (Ge) to lower tmaterial costs, reduce sensitivity to ambient water and oxygen, and achieve acceptable Li+ conductivity. The ab initio first principle molecular dynamics simulations show that room-temperature Li+ conductivity is 1.12 mS·cm−1 for the Li10Ge0.75Mo0.25P2S12 compound, which is comparable to the theoretical value of 6.81 mS·cm−1 and the experimental measured one of 12 mS·cm−1 of the Li10GeP2S12 (LGPS) structure. For Li10GexMo1−xP2S12 (x = 0, 0.25, 0.5 and 1) compounds, the density of states and the projection fractional wave state density were calculated. It was found that when Ge atoms were partially replaced by Mo atoms, the band gap remained unchanged at 2.5 eV, but deep level defects appeared in Mo-substituted compounds. Fortunately, this deep level defect is difficult to ionize at room temperature, so it has no effect on the electronic conductivity of Mo substitute compounds, making Mo substitution a suitable solution for electrolyte materials. The projection fractional wave state density calculation shows that the covalent bond between Mo and S is stronger than that between Ge and S, which reduces the sensitivity of Mo-substituted compounds to water and oxygen contents in the air. In addition, the partial state density coincidence curve between Li and S elements disappears in the 25% Mo-substituted compound with energies of 4–5 eV, indicating that the Li2S by-product is decreased. [ABSTRACT FROM AUTHOR]

Porous organic polymers (POPs) are emergent tailor‐made materials, which can be accessed by covalent polymerization of diligently designed molecular building blocks in a bottom‐up fashion. Acridone, a well‐known chromophore that undergoes intersystem crossing (ISC) with near‐unity quantum yield akin to benzophenone, was structurally elaborated into a building block and subjected to Friedel‐Crafts polyalkylation to afford a series of POPs, namely, Ac‐MePOP, Ac‐OMePOP, and Ac‐CBPOP. These POPs exhibit remarkable porosity and significant absorption in the visible region. Of the three polymers, Ac‐CBPOP with the highest BET surface area of ca. 1027 m2/g is shown to serve as an excellent heterogeneous photocatalyst for visible light‐mediated oxidative transformations, that is, oxidative coupling of benzylamines to imines and cyclocondensation of o‐phenylenediamines with aldehydes to benzimidazoles under oxygen atmosphere. It is further shown that Ac‐CBPOP can be reused for several reaction cycles without any loss of catalytic activity with its stability intact. Mechanistic studies show that 1O2 serves as the key reactive oxygen species, formed by the energy transfer from Ac‐CBPOP to 3O2, in the photocatalytic oxidation reactions. The results demonstrate the development of stable photocatalytic POP materials with tailor‐made properties by a bottom‐up covalent polymerization of programmed molecular building blocks. [ABSTRACT FROM AUTHOR]

The natural aroma compound (+)-nootkatone was obtained in selective conversions of up to 74 mol% from inexpensive (+)-valencene substrate by using a comparatively greener biocatalytic process developed based on modifications of the previously published Firmenich method. Buffer identity and concentration, pH, temperature and downstream work-up procedures were optimized to produce a crude product in which >90 % of (+)-valencene had been converted, with high chemoselectivity observed for (+)-nootkatone production. Interestingly, the biotransformation was carried out efficiently at temperatures as low as 21 ºC. Surprisingly, the best results were obtained when an acidic pH in the range of 3–6 was applied, as compared to the previously published procedure in which it appeared to be necessary to buffer the pH optimally and fixed throughout at 8.5. Furthermore, there was no need to maintain a pure oxygen atmosphere to achieve good (+)-nootkatone yields. Instead, air bubbled continuously at a low rate through the reaction mixture via a submerged glass capillary was sufficient to enable the desired lipoxygenase-catalyzed oxidation reactions to occur efficiently. No valencene epoxide side-products were detected in the organic product extract by a standard GCMS protocol. Only traces of the anticipated corresponding α- and β-nootkatol intermediates were routinely observed. [Display omitted] • A greener method was developed to produce (+)-nootkatone biocatalytically. • An unprecedentedly high conversion of 74 mol% (+)-nootkatone was obtained from inexpensive valencene. • Surprisingly, soy bean LOX isozymes were found to perform optimally in the pH range 4-6 and catalyzed the desired reaction at a pH as low as 2. [ABSTRACT FROM AUTHOR]

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 po2 = 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. [ABSTRACT FROM AUTHOR]

Amino-cured epoxy resins are widely used in the electrical and electronic industry for their excellent properties. To investigate the mechanism of the effect of O2 and H2O on the pyrolysis behavior of epoxy resin, in this paper, the cross-linked structure of bisphenol A type epoxy resin cured by adducts of diethylenetriamine and butyl glycidyl ether is modeled based on the ReaxFF force field, and the thermal decomposition processes at different temperatures and gas atmospheres were simulated and the pathways of the small molecule products were clarified. The results show that epoxy resin will produce small molecule gas products, such as H2, CO, H2O, OH, CH2O, and free radicals, in the process of pyrolysis; the presence of amino groups also generates nitrogen-containing radicals, such as CN, CH2N, and C2H4N; as the reaction temperature increases, the rate of pyrolysis reaction will be accelerated. The same temperature in oxygen and water atmospheres can accelerate the breakage of epoxy resin main chain by promoting the breakage of carbon and oxygen bonds and, at the same time, promote the generation of small molecule gases, such as H2 and CO. [ABSTRACT FROM AUTHOR]

Spinel-type InGaMgO4 with a = 8.56615(3) Å was prepared by treating layered YbFe2O4-type InGaMgO4 at 6 GPa and 1473 K. DFT calculation and Rietveld analysis of synchrotron X-ray powder diffraction data revealed the inverse spinel structure with In3+:Ga3+/Mg2+ = 0.726:0.274 in the tetrahedral site and 0.137:0.863 in the octahedral site. InGaMgO4 spinel is an insulator with an experimental band gap of 2.80 eV, and the attempt at hole doping by post-annealing in a reducing atmosphere to introduce an oxygen defect was unsuccessful. This is the first report of the bulk synthesis of AB2O4 compounds with both YbFe2O4 and spinel polymorphs. [ABSTRACT FROM AUTHOR]

The skin is made up of different layers with various gradients, which maintain a complex microenvironment, particularly in terms of oxygen levels. However, all types of skin cells are cultured in conventional incubators that do not reproduce physiological oxygen levels. Instead, they are cultured at atmospheric oxygen levels, a condition that is far removed from physiology and may lead to the generation of free radicals known to induce skin ageing. This review aims to summarize the current literature on the effect of physiological oxygen levels on skin cells, highlight the shortcomings of current in vitro models, and demonstrate the importance of respecting skin oxygen levels. We begin by clarifying the terminology used about oxygen levels and describe the specific distribution of oxygen in the skin. We review and discuss how skin cells adapt their oxygen consumption and metabolism to oxygen levels environment, as well as the changes that are induced, particularly, their redox state, life cycle and functions. We examine the effects of oxygen on both simple culture models and more complex reconstructed skin models. Finally, we present the implications of oxygen modulation for a more therapeutic approach. [Display omitted] • Skin cells are physiologically in a microenvironment poor in oxygen called physioxia. • Skin physioxia is not taken into account in in vitro models. • Physioxia affects cutaneous cell metabolism. • Physioxia impacts skin cell proliferation, differentiation and senescence. • Physioxia modulates skin cell migration, pigmentation and angiogenesis. [ABSTRACT FROM AUTHOR]

Modified atmosphere package (MAP), as a practical, economic, and easy to operate food package technique, has experienced a rapid development in both scientific and industrial communities. In recent years, given the superiority of super-atmospheric O2 (SO) MAP in preserving fruits and vegetables relative to low O2 and/or high CO2 MAP, SO MAP is back on the radar of researchers. This paper systematically reviews recent development on application of SO MAP and improved strategies to fruit and vegetable preservation in the last 15 years, possible mechanisms concerning their positive and negative effects, and challenges and future perspectives for SO MAP. The present work can provide a theoretical basis and technique reference for achieving a better effectiveness on fruit and vegetable preservation in the practical application. [ABSTRACT FROM AUTHOR]

The early Cambrian witnessed an increase in metazoan ecosystem complexity, likely linked to enhanced oxygen and nutrient availability. However, while improved stratigraphic and geochemical records suggest that the Cambrian explosion occurred under highly dynamic redox conditions, mechanistic links to nutrient availability and early Cambrian evolutionary innovations are poorly constrained. Here, we report paleoredox and nutrient data for two drill cores documenting late Cambrian Stage 2 to Stage 3 (ca. 522–514 Ma) strata from the Yangtze block, South China. The development of water-column euxinia during Cambrian Stage 2 led to extensive recycling of P, fueling elevated primary production and hence an increase in atmospheric and shallow-marine oxygen concentrations. The resulting expansion of oxygenated shelf area promoted sedimentary P retention and, in combination with a diminished supply of P from upwelling, drove a transition to oligotrophic shallow-marine conditions during Cambrian Stage 3. Reduced primary production and limited water-column oxygen consumption allowed for the stabilization of oxygenated continental shelf habitats that supported a burgeoning biotic complexity. [ABSTRACT FROM AUTHOR]

Sodium borohydride induces the oxidative expansion of the imine derived from isatin and phenylethylamine to form 3-phenethylquinazoline-2,4(1H,3H)-dione. It has been proposed that this transformation occurs by in situ formation of hydroperoxyl anions by a reaction between sodium borohydride and atmospheric oxygen. To contribute to understanding this oxidative expansion, the reaction between the imine derived from isatin and phenylethylamine with hydrogen peroxide was studied in this work. From this reaction, 3-phenethylquinazoline-2,4(1H,3H)-dione was isolated and two by-products were identified: N-phenethyl-2-(3-phenethyl-ureido)-benzamide and methyl(2-(phenethylcarbamoyl)phenyl)carbamate. This article analyses the structure of these by-products and proposes a mechanism that explains the reaction. It was established that the reaction of the imine derived from isatin and phenylethylamine with hydrogen peroxide produces a mixture of three compounds: 3-phenethylquinazoline-2,4(1H,3H)-dione, N-phenethyl-2-(3-phenethyl-ureido)-benzamide and methyl(2-(phenethylcarbamoyl)phenyl)carbamate. A reaction mechanism is proposed that explains this behaviour [ABSTRACT FROM AUTHOR]

In this work, we investigated the seasonal cycle of atmospheric potential oxygen (APO), a unique tracer of air‐sea gas exchanges of molecular oxygen (O2) and carbon dioxide (CO2), expressed as APO = O2 + 1.1 × CO2. APO data were obtained from flask air samples collected since the late 1990s at three Japanese ground stations and on commercial cargo ships sailing between Japan and Australia/New Zealand, North America, and Southeast Asia. We also analyzed the APO spatial distribution and seasonal cycles with simulations from an atmospheric transport model using climatological oceanic O2 fluxes from an empirical product that relate O2 flux to ocean heat as input. Model simulations reproduced the observed APO seasonal cycles generally well, but with larger amplitudes and earlier occurrence of seasonal minima and maxima than in the observations. Moreover, the observed seasonal cycles exhibited larger APO enhancements than the simulations in autumn and early winter, especially in the North Pacific at 20°N–60°N. These enhancements remained when refining the comparison by adjusting the simulated APO peak‐to‐peak amplitudes and seasonal phases to the observations. This suggests additional O2 emissions in the North Pacific, not well expressed in the air‐sea O2 fluxes used as input for our model simulations. The average autumn enhancement at 40°N–60°N was approximately twice that measured at 20°N–40°N. Confirming previous studies, our results indicate two distinct mechanisms possibly contributing to the additional oceanic O2 emissions: outgassing from a subsurface shallow oxygen maximum at 20°N–40°N and autumn phytoplankton bloom at 40°N–60°N. Plain Language Summary: Seasonal variations of air‐sea molecular oxygen (O2) exchanges are mainly driven by spring/summer emission and autumn/winter absorption. Emission results mainly from O2 production by phytoplankton at the ocean surface; absorption is related to O2 uptake in deep oxygen‐depleted water layers caused by oceanic ventilation. A phytoplankton bloom in autumn and outgassing from water rich in dissolved O2 just below the mixed layer, known as the shallow oxygen maximum, have been suggested as possible mechanisms contributing to the O2 seasonal cycles. Unfortunately, these oceanic autumn O2 emissions are not well characterized. In this study, we analyzed air samples collected in the western and northern Pacific to evaluate the oceanic component of the O2 seasonal cycle, known as "atmospheric potential oxygen" and calculated as the sum of atmospheric O2 and carbon dioxide. By comparing these observations with model simulations that used previous air‐sea O2 flux estimates as input, we identified marked enhancements in autumn at latitudes between 20°N and 60°N in the Pacific. This corresponds to the geographic area where the autumn phytoplankton bloom and the shallow oxygen maximum occur. This result is a strong indication of additional autumn O2 emissions in the extratropical North Pacific. Key Points: We analyzed atmospheric potential oxygen (APO), a tracer of air‐sea exchanges of molecular oxygen (O2) and carbon dioxide, in the PacificThe observed seasonal APO enhancement at 20°N–60°N in autumn, relative to model simulations, suggests additional oceanic O2 emissionsOutgassing from a shallow oxygen maximum (20–40°N) and an autumn phytoplankton bloom (40–60°N) likely contribute to this enhancement [ABSTRACT FROM AUTHOR]

MgO–C refractories are of paramount importance in the converter side blowing system, requiring outstanding oxidation resistance under harsh conditions including high temperature, oxygen atmosphere, and high‐speed airflow. In this study, MgSiN2 phase reconstruction was used to improve the oxidation resistance of MgO–C refractories, as well as the mechanical properties and oxidation resistance of MgO–C refractories were evaluated. The results indicated that the cold modulus of rupture of the sample with 9 wt% MgSiN2 was increased by 93.3% compared with the MgO–C refractories without MgSiN2. After oxidation tests, the oxidation index and rate constant (k) of the sample with 9 wt% MgSiN2 were reduced by 38.9% and 35.3%. Furthermore, incorporating MgSiN2 facilitated the formation of layered dense structures consisting of plate‐like Mg‐Sialon and MgO–Mg2SiO4–MgAl2O4. This structural optimization effectively inhibited oxygen diffusion and reaction within the material, resulting in gradual oxygen potential mitigation. [ABSTRACT FROM AUTHOR]

• Oxygen-filled ball milling remarkably promotes the remediation of PCS. • Expose more functional components onto soil surface to adsorb metals. • Generate more 1O 2 and accelerate electron transfer to enhance PDS oxidation. • The recovered metals improve PDS activation efficiency and reusability. • Simultaneously realize efficient remediation and sequential reuse of PCS. Ball milling is an environmentally friendly technology for the remediation of petroleum-contaminated soil (PCS), but the cleanup of organic pollutants requires a long time, and the post-remediation soil needs an economically viable disposal/reuse strategy due to its vast volume. The present paper develops a ball milling process under oxygen atmosphere to enhance PCS remediation and reuse the obtained carbonized soil (BCS-O) as wastewater treatment materials. The total petroleum hydrocarbon removal rates by ball milling under vacuum, air, and oxygen atmospheres are 39.83%, 55.21%, and 93.84%, respectively. The Langmuir and pseudo second-order models satisfactorily describe the adsorption capacity and behavior of BCS-O for transition metals. The Cu2+, Ni2+, and Mn2+ adsorbed onto BCS-O were mainly bound to metal carbonates and metal oxides. Furthermore, BCS-O can effectively activate persulfate (PDS) oxidation to degrade aniline, while BCS-O loaded with transition metal (BCS-O-Me) shows better activation efficiency and reusability. BCS-O and BCS-O-Me activated PDS oxidation systems are dominated by 1 O 2 oxidation and electron transfer. The main active sites are oxygen-containing functional groups, vacancy defects, and graphitized carbon. The oxygen-containing functional groups and vacancy defects primarily activate PDS to generate 1 O 2 and attack aniline. Graphitized carbon promotes aniline degradation by accelerating electron transfer. The paper develops an innovative strategy to simultaneously realize efficient remediation of PCS and sequential reuse of the post-remediation soil. [Display omitted] [ABSTRACT FROM AUTHOR]

MgO–C refractories are of paramount importance in the converter side blowing system, requiring outstanding oxidation resistance under harsh conditions including high temperature, oxygen atmosphere, and high‐speed airflow. In this study, MgSiN2 phase reconstruction was used to improve the oxidation resistance of MgO–C refractories, as well as the mechanical properties and oxidation resistance of MgO–C refractories were evaluated. The results indicated that the cold modulus of rupture of the sample with 9 wt% MgSiN2 was increased by 93.3% compared with the MgO–C refractories without MgSiN2. After oxidation tests, the oxidation index and rate constant (k) of the sample with 9 wt% MgSiN2 were reduced by 38.9% and 35.3%. Furthermore, incorporating MgSiN2 facilitated the formation of layered dense structures consisting of plate‐like Mg‐Sialon and MgO–Mg2SiO4–MgAl2O4. This structural optimization effectively inhibited oxygen diffusion and reaction within the material, resulting in gradual oxygen potential mitigation. [ABSTRACT FROM AUTHOR]

Obtaining new materials with antibacterial activity is an urgent task due to the emergence and proliferation of new antibiotic resistant strains, as well as the increasing requirements for the effectiveness and toxicity of such materials. Electrical explosion of two twisted wires (EETW) to produce of heterophase nanoparticles is attractive for develop novel antibacterial agents. Our work describes simple and environmental friendly way to obtain novel composite CuO/Cu2O/Ag nanoparticles with different silver mass ratio (15, 50, 90%) by the simultaneous electrical explosion of Ag and Cu twisted wires in oxygen containing atmosphere. The using of EETW for the production of heterophase NPs is due to several advantages such as high purity of nanoparticles, good productivity (about 120 g nanoparticles per hour) and eco-friendliness. The obtained nanoparticles have irregular spherical shape morphology. According to EDX analysis dates, the nanoparticles have Janus-like structure, where one part is enriched with Ag and the other with Cu and O. The mean particle size depended on silver content and was 63 ± 2 nm (90% Ag), 92 ± 2 nm (15% Ag). CuO/Cu2O/(50)Ag particle size distribution have two peaks, one at 35 ± 1 nm and the other at 79 ± 2 nm. The NP zeta potential of nanoparticles measured neutral pH and 25 °C was positive (more than 20 mV). CuO/Cu2O/Ag nanoparticles with 50% Ag significantly inhibited the growth of methicillin-resistant Staphylococcus aureus (MRSA) with MIC = 62 µg/mL. The antibacterial activity nanoparticles with 90%Ag determined by the disco-diffusion method was slightly lower than that of the nanoparticles with 15 and 50% Ag. The possible antibacterial mechanisms may be attributed to the synergistic effect of the heterostructure of EETW nanoparticles and the formation of galvanic nanopairs. The presence of silver metal and copper oxides in nanoparticles can promote galvanic corrosion, leading to the release of more metal ions into the bacterial suspension. We have shown that the nanoparticles obtained have a positive zeta potential, unlike Ag nanoparticles, which may contribute to a better adhesion of nanoparticles to the surface of bacterial cells. The synthesized NPs have broad potential to be developed in pharmaceutics as an effective antimicrobial nanomaterial. [ABSTRACT FROM AUTHOR]

Bismuth ferrite (BiFeO3)‐based high‐temperature piezoelectric ceramics have high Curie temperatures and excellent thermal stability; however, their applications are limited by inadequate piezoelectric performance due to large coercive fields and high leakage conduction. This study investigates the impact of MnO2 doping on the phase transition, defect structure, domain morphology, as well as the dielectric, ferroelectric, and electrical conduction behaviors of 75BiFeO3–25BaTiO3 ceramics sintered under an oxygen atmosphere. A structural transformation from distorted rhombohedral to pseudo‐cubic symmetry was observed with increasing MnO2 content, accompanied by domain fragmentation. MnO2 doping at an appropriate level inhibited defects such as Fe′Fe$\ {\mathrm{F}}{{{\mathrm{e^{\prime}}}}_{{\mathrm{Fe}}}}$ and VO2−⋅⋅$V_{{{{\mathrm{O}}}^{{\mathrm{2}} - }}}^{\centerdot \centerdot }$. Regarding electrical properties, the reduction in rhombohedral distortion and enhancement in the pseudo‐cubic phase after MnO2 doping resulted in decreased remanent polarization and electrostrain, which could potentially hinder piezoelectric response. However, appropriate MnO2 doping effectively reduced leakage conduction, significantly enhancing the poling efficiency of the ceramics. The maximum d33 value of 107 pC/N and kp of 0.36 were achieved at an MnO2 doping content of 0.1 wt.%. Excessive MnO2 addition may generate 2Mn′Ti−VO2−⋅⋅${\mathrm{2M}}{{{\mathrm{n^{\prime}}}}_{{\mathrm{Ti}}}}-V_{{{{\mathrm{O}}}^{{\mathrm{2}} - }}}^{\centerdot \centerdot }$ defect dipoles, as indicated by increased coercive field (Ec) and dielectric loss. The observed increase in high‐temperature resistivity with MnO2 content is primarily attributed to reduced grain size and increased concentration of mobile defects. This study provides valuable insights for further research on the application of 75BiFeO3–25BaTiO3 systems in high‐temperature piezoelectric devices. [ABSTRACT FROM AUTHOR]

The corrosion of SiCf/SiC composites in gas environment threatens their long‐term service in aeroengines as hot‐end structure components. Addition of corrosion‐resistant phases into SiC matrix is a potential strategy to improve the service performance of SiCf/SiC materials. Here, AlN added SiC ceramics were prepared by reactive melt infiltration, and the effect of AlN phase on the oxidation resistance of the ceramics was emphasized. The oxidation tests were performed in dry oxygen and water oxygen atmospheres at 1100°C–1300°C, respectively. The oxidation mechanism was discussed based on the microstructure evolution of the oxide layer. The results show that the oxide layer is composed of aluminum silicate glass and Al2O3 flakes dispersedly distributed in the glass phase. As the temperature rises, the oxide layer gradually grows and thickens. Finally, a smooth and dense protective layer could be formed on the surface of ceramics to resist oxidation. This study can provide a profound insight to construct SiCf/SiC composites with excellent oxidation resistance. [ABSTRACT FROM AUTHOR]

A new, Earth System Model of Intermediate Complexity, DCESS II, is presented that builds upon, improves and extends the Danish Center for Earth System Science (DCESS) Earth System model (DCESS I). DCESS II has considerably greater spatial resolution than DCESS I while retaining the fine, 100 m vertical resolution in the ocean. It contains modules for the atmosphere, ocean, ocean sediment, land biosphere and lithosphere and is designed to deal with global change simulations on scales of years to millions of years while using limited computational resources. Tracers of the atmospheric module are temperature, nitrous oxide, methane (12,13C isotopes), carbon dioxide (12,13,14C isotopes) and atmospheric oxygen. For the ocean module, tracers are conservative temperature, absolute salinity, water 18O, phosphate, dissolved inorganic carbon (12,13,14C isotopes), alkalinity and dissolved oxygen. Furthermore, the ocean module considers simplified dynamical schemes for large-scale meridional circulation and sea-ice dynamics, stratification-dependent vertical diffusion, a gravity current approach to the formation of Antarctic Bottom Water and improvements in ocean biogeochemistry. DCESS II has two hemispheres with six zonal-averaged atmospheric boxes and twelve ocean boxes distributed across the Indian-Pacific, the Atlantic, the Arctic and the Southern Oceans. A new, extended land biosphere scheme is implemented that considers three different vegetation types whereby net primary production depends on sunlight and atmospheric carbon dioxide. The ocean sediment and lithosphere model formulations are adopted from DCESS I but now applied to the multiple ocean and land regions of the new model. A model calibration was carried out for the pre-industrial climate and model steady-state solutions were compared against available modern-day observations. For the most part, calibration results agree well with observed data, included excellent agreement with ocean carbon species. This serves to demonstrate model utility for dealing with the global carbon cycle. Finally, two idealized experiments were carried out in order to explore model performance. First, we forced the model by varying Ekman transport out of the model Southern Ocean, mimicking the effect of Southern Hemisphere westerly wind variations and second, we imposed freshwater melting pulses from the Antarctic ice sheet on to the model Southern Ocean shelf. Changes in ocean circulation and in the global carbon cycle found in these experiments are reasonable and agree with results for much more complex models. Thus, we find DCESS II to be a useful and computational-friendly tool for simulations of past climates as well as for future Earth System projections. [ABSTRACT FROM AUTHOR]

The synthesis of substituted pyrazines from readily available methyl aryl/heteroaryl ketones and 1,2‐diamines was achieved using highly stable and reusable ferrite‐stabilized copper nanoparticles (Fe3O4‐CuO) as a catalyst. The reaction proceeds through a cascade imine formation–oxidative cyclization method under an oxygen atmosphere. The nanocatalysts were readily recovered and reused up to three consecutive cycles without any significant decrease in particle size, catalytic activity and reaction yield, as evidenced by analytical techniques such as transmission electron microscopy (TEM) and powder X‐ray diffraction (PXRD). The synthesized pyrazines exhibited photophysical behaviour, displayed large Stokes shifts, and were explored as fluorescent probes for the sensitive as well as selective "turn‐off" detection of iron with a limit of detection of 0.63 μM. The sensing method is also useful for the quantification of iron in spiked water samples. Furthermore, the application of luminescent pyrazines as fluorescent ink was successfully demonstrated. [ABSTRACT FROM AUTHOR]

To improve the strength of Al 2 O 3 specimens produced using the water-stabilized plasma spraying technique (WSPSAO), this study investigates the effect of structural modification on the mechanical properties of WSPSAO using the Al-Cu-O reaction between the metal, atmospheric oxygen, and base material. A Cu-powder layer is applied to the specimen surface, melted, and oxidized at high temperatures. It penetrates into the specimen, resulting in significant microstructural modification deep in the specimen. After modification, uniaxial Al 2 O 3 , CuO, Cu 2 O, and CuAl 2 O 4 are formed in the specimen, resulting in a denser and more uniform structure than that of the original material. The bending strength of the coated surface is 145 MPa, and that on the opposite side of the coated surface is 118 MPa, which is 130%–180% higher than the original strength of the base material. [ABSTRACT FROM AUTHOR]