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IntroductionOxidative stress mediated by reactive oxygen species (ROS) is a key process for adverse aerosol health effects. Secondary organic aerosols (SOA) account for a major fraction of particulate matter with aerodynamic diameter ≤2.5 µm (PM2.5). PM2.5 inhalation and deposition into the respiratory tract causes the formation of ROS by chemical reactions and phagocytosis of macrophages in the epithelial lining fluid (ELF), but their relative contributions are not well quantified and their link to oxidative stress remains uncertain. The specific aims of this project were (1) elucidating the chemical mechanism and quantifying the formation kinetics of ROS in the ELF by SOA; (2) quantifying the relative importance of ROS formation by chemical reactions and macrophages in the ELF.MethodsSOA particles were generated using reaction chambers from oxidation of various precursors including isoprene, terpenes, and aromatic compounds with or without nitrogen oxides (NOx). We collected size-segregated PM at two highway sites in Anaheim, CA, and Long Beach, CA, and at an urban site in Irvine, CA, during two wildfire events. The collected particles were extracted into water or surrogate ELF that contained lung antioxidants. ROS generation was quantified using electron paramagnetic resonance (EPR) spectroscopy with a spin-trapping technique. PM oxidative potential (OP) was also quantified using the dithiothreitol assay. In addition, kinetic modeling was applied for analysis and interpretation of experimental data. Finally, we quantified cellular superoxide release by RAW264.7 macrophage cells upon exposure to quinones and isoprene SOA using a chemiluminescence assay as calibrated with an EPR spin-probing technique. We also applied cellular imaging techniques to study the cellular mechanism of superoxide release and oxidative damage on cell membranes.ResultsSuperoxide radicals (·O2-) were formed from aqueous reactions of biogenic SOA generated by hydroxy radical (·OH) photooxidation of isoprene, β-pinene, α-terpineol, and d-limonene. The temporal evolution of ·OH and ·O2- formation was elucidated by kinetic modeling with a cascade of aqueous reactions, including the decomposition of organic hydroperoxides (ROOH), ·OH oxidation of primary or secondary alcohols, and unimolecular decomposition of α-hydroxyperoxyl radicals. Relative yields of various types of ROS reflected the relative abundance of ROOH and alcohols contained in SOA, which generated under high NOx conditions, exhibited lower ROS yields. ROS formation by SOA was also affected by pH. Isoprene SOA had higher ·OH and organic radical yields at neutral than at acidic pH. At low pH ·O2- was the dominant species generated by all types of SOA. At neutral pH, α-terpineol SOA exhibited a substantial yield of carbon-centered organic radicals (R·), while no radical formation was observed by aromatic SOA.Organic radicals in the ELF were formed by mixtures of Fe2+ and SOA generated from photooxidation of isoprene, α-terpineol, and toluene. The molar yields of organic radicals by SOA were 5-10 times higher in ELF than in water. Fe2+ enhanced organic radical yields by a factor of 20-80. Ascorbate mediated redox cycling of iron ions and sustained organic peroxide decomposition, as supported by kinetic modeling reproducing time- and concentration-dependence of organic radical formation, as well as by additional experiments observing the formation of Fe2+ and ascorbate radicals in mixtures of ascorbate and Fe3+. ·OH and superoxide were found to be efficiently scavenged by antioxidants.Wildfire PM mainly generated ·OH and R· with minor contributions from superoxide and oxygen-centered organic radicals (RO·). PM OP was high in wildfire PM, exhibiting very weak correlation with radical forms of ROS. These results were in stark contrast with PM collected at highway and urban sites, which generated much higher amounts of radicals dominated by ·OH radicals that correlated well with OP. By combining field measurements of size-segregated chemical composition, a human respiratory tract model, and kinetic modeling, we quantified production rates and concentrations of different types of ROS in different regions of the ELF by considering particle-size-dependent respiratory deposition. While hydrogen peroxide (H2O2) and ·O2- production were governed by Fe and Cu ions, ·OH radicals were mainly generated by organic compounds and Fenton-like reactions of metal ions. We obtained mixed results for correlations between PM OP and ROS formation, providing rationale and limitations of the use of oxidative potential as an indicator for PM toxicity in epidemiological and toxicological studies.Quinones and isoprene SOA activated nicotinamide adenine dinucleotide phosphate (NADPH) oxidase in macrophages, releasing massive amounts of superoxide via respiratory burst and overwhelming the superoxide formation by aqueous chemical reactions in the ELF. The threshold dose for macrophage activation was much smaller for quinones compared with isoprene SOA. The released ROS caused lipid peroxidation to increase cell membrane fluidity, inducing oxidative damage and stress. Further increases of doses led to the activation of antioxidant response elements, reducing the net cellular superoxide production. At very high doses and long exposure times, chemical production became comparably important or dominant if the escalation of oxidative stress led to cell death.ConclusionsThe mechanistic understandings and quantitative information on ROS generation by SOA particles provided a basis for further elucidation of adverse aerosol health effects and oxidative stress by PM2.5. For a comprehensive assessment of PM toxicity and health effects via oxidative stress, it is important to consider both chemical reactions and cellular processes for the formation of ROS in the ELF. Chemical composition of PM strongly influences ROS formation; further investigations are required to study ROS formation from various PM sources. Such research will provide critical information to environmental agencies and policymakers for the development of air quality policy and regulation.

Low-cost stainless-steel electrodes can activate hydrogen peroxide (H2O2) by converting it into a hydroxyl radical (•OH) and other reactive oxidants. At an applied potential of +0.020 V, the stainless-steel electrode produced •OH with a yield that was over an order of magnitude higher than that reported for other systems that employ iron oxides as catalysts under circumneutral pH conditions. Decreasing the applied potential at pH 8 and 9 enhanced the rate of H2O2 loss by shifting the process to a reaction mechanism that resulted in the formation of an Fe(IV) species. Significant metal leaching was only observed under acidic pH conditions (i.e., at pH

While the poor prognosis of glioblastoma arises from the invasion of a subset of tumor cells, little is known of the metabolic alterations within these cells that fuel invasion. We integrated spatially addressable hydrogel biomaterial platforms, patient site-directed biopsies, and multiomics analyses to define metabolic drivers of invasive glioblastoma cells. Metabolomics and lipidomics revealed elevations in the redox buffers cystathionine, hexosylceramides, and glucosyl ceramides in the invasive front of both hydrogel-cultured tumors and patient site-directed biopsies, with immunofluorescence indicating elevated reactive oxygen species (ROS) markers in invasive cells. Transcriptomics confirmed upregulation of ROS-producing and response genes at the invasive front in both hydrogel models and patient tumors. Among oncologic ROS, H2O2 specifically promoted glioblastoma invasion in 3D hydrogel spheroid cultures. A CRISPR metabolic gene screen revealed cystathionine γ-lyase (CTH), which converts cystathionine to the nonessential amino acid cysteine in the transsulfuration pathway, to be essential for glioblastoma invasion. Correspondingly, supplementing CTH knockdown cells with exogenous cysteine rescued invasion. Pharmacologic CTH inhibition suppressed glioblastoma invasion, while CTH knockdown slowed glioblastoma invasion in vivo. Our studies highlight the importance of ROS metabolism in invasive glioblastoma cells and support further exploration of the transsulfuration pathway as a mechanistic and therapeutic target.

Organic peroxides are key intermediates in the atmosphere but are challenging to detect, especially in the particle phase, due to their instability, which has led to substantial gaps in the understanding of their environmental effects. We demonstrate that matrix-assisted ionization in vacuum (MAIV) mass spectrometry (MS), which does not require an ionization source, enables in situ characterization of peroxides and other products in the surface layers of organic particles. Hydroxyl radical oxidation of glutaric acid particles yields hydroperoxides and organic peroxides, which were detected with signals of the same order of magnitude as the major, more stable products. Product identification is supported by MS/MS analysis, peroxide standards, and offline high-resolution MS. The peroxide signals relative to the stable carbonyl and alcohol products are significantly larger using MAIV compared to those in the offline bulk analysis. This is also the case for analysis using fast, online easy ambient sonic-spray ionization mass spectrometry. These studies demonstrate the advantage of MAIV for the real-time characterization of labile peroxides in the surface layers of solid particles. The presence of peroxides on the surface may be important for surface oxidation processes as well as for the toxicity of inhaled particles.

The purpose of this study was to evaluate the effects of desensitizing MI Varnish (GC America) applied before or after bleaching on the mineral component of enamel and surface topography. The coronal portions of 10 freshly extracted bovine teeth were segmented for a total of 40 specimens. Enamel specimens obtained from each tooth were randomly divided into four groups (n = 10): Group A = no bleaching; Group B = bleaching with 40% hydrogen peroxide (HP); Group C = MI Varnish applied before bleaching; and Group D = MI Varnish applied after bleaching. The calcium (Ca) and phosphorus (P) levels of the specimens in each group were determined by energy dispersive spectroscopy (EDS). Morphologic changes were observed using scanning electron microscopy (SEM). One-way ANOVA and Tukey HSD tests were used for statistical analyses (α = .05). The mean Ca content of Group B was significantly lower than those of Groups A, C, and D (P < .05). The mean Ca content of Group C was significantly lower than that of Group A (P < .05). There was no significant difference in Ca content between the other groups (P > .05). The mean P content of Group A was significantly higher than those of Groups B to D (P < .05). There was no significant difference in P content between Groups B to D (P > .05). Application of MI Varnish before or after in-office bleaching was effective in reducing mineral loss. However, applying MI Varnish after bleaching was more effective. [ABSTRACT FROM AUTHOR]

This study assessed the effectiveness and predictability of a readily available protocol to treat peri-implantitis utilizing mechanical debridement, chemical antiseptic surface detoxification, and osseous grafting. Nine patients (7 women, 2 men; mean age: 56.5 years) with 15 implants with peri-implantitis were included. Pocket probing depth (PPD), bleeding on probing (BOP), and standardized digital periapical radiographic measurements were taken. Surgical flaps were elevated, and the implant threads were cleaned with a plastic curette. Chemical decontamination was performed by scrubbing solutions of 0.25% sodium hypochlorite (NaClO) and 1.5% hydrogen peroxide (H2O2) around the exposed implant using cotton pellets. Bony defects were filled with a 50/50 mixture of bovine hydroxyapatite and nanocrystalline calcium sulfate (CaSO4). A porcine collagen membrane was placed over the grafted bony defect. Follow-up appointments were scheduled 1 week, 2 weeks, 3 months, 6 months, 9 months, and 1 year posttreatment. Clinical and radiographic parameters were assessed and compared. At baseline, PPD ranged from 5 to 7.5 mm (mean: 6 ± 0.7 mm). At 12 months, PPD ranged from 1.5 to 4.2 mm (mean: 2.5 ± 0.8 mm). The mean PPD reduction of 3.6 mm (59.2%) was statistically significant (P < .001). The number of bleeding sites around each test implant decreased significantly from 4 to 0.4 sites between baseline and 12 months (P < .001). Mean radiographic bone loss decreased from 4.8 ± 1.3 mm to 2.7 ± 1.2 mm (P < .001). The proposed method of mechanical decontamination, chemical detoxification, and bone regeneration is clinically effective and reproducible. Clinical peri-implant parameters and radiographic bone levels were improved and maintained their stability for 1 year using this peri-implantitis treatment protocol. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate different protocols for recementation of dislodged glass fiber posts (GFPs).Materials and Methods: The root canals of 50 bovine incisors were prepared to receive GFPs, which were conditioned with 24% hydrogen peroxide, silanized, and cemented with a self-adhesive resin cement. After light curing, the specimens were submitted to a pullout test. The dislodged GPFs were distributed into five experimental groups (n = 10 each) according to surface treatment for recementation: NT = no treatment; SI = silane; ET = 92.8% ethanol/silane; HP = 24% hydrogen peroxide/silane; AL = airborne-particle abrasion (50-μm alumina)/silane. The GFPs were recemented with the same self-adhesive resin cement, and specimens were submitted to a second pullout test. Data were analyzed by Student t test and one-way ANOVA (α = .05).Results: For all groups, the recementation bond strength was higher than the strength obtained after the first cementation (P < .05). There were no statistical differences among the experimental recementation protocols (P = .096).Conclusion: All recementation protocols might be reliably applied since they led to higher bond strength than the first cementation. [ABSTRACT FROM AUTHOR]

Root-knot nematodes (Meloidogyne spp., RKN) are responsible for extensive crop losses worldwide. During infection, they penetrate plant roots, migrate between plant cells, and establish feeding sites, known as giant cells, near the root vasculature. Previously, we found that nematode perception and early responses in plants were similar to those of microbial pathogens and required the BRI1-ASSOCIATED KINASE1/SOMATIC EMBRYOGENESIS RECEPTOR KINASE3 (BAK1/SERK3) coreceptor in Arabidopsis (Arabidopsis thaliana) and tomato (Solanum lycopersicum). Here, we implemented a reverse genetic screen for resistance or sensitivity to RKN using Arabidopsis T-DNA alleles of genes encoding transmembrane receptor-like kinases to identify additional receptors involved in this process. This screen identified a pair of allelic mutations with enhanced resistance to RKN in a gene we named ENHANCED RESISTANCE TO NEMATODES1 (ERN1). ERN1 encodes a G-type lectin receptor kinase (G-LecRK) with a single-pass transmembrane domain. Further characterization showed that ern1 mutants displayed stronger activation of MAP kinases, elevated levels of the defense marker MYB51, and enhanced H2O2 accumulation in roots upon RKN elicitor treatments. Elevated MYB51 expression and ROS bursts were also observed in leaves of ern1 mutants upon flg22 treatment. Complementation of ern1.1 with 35S- or native promoter-driven ERN1 rescued the RKN infection and enhanced defense phenotypes. Our results indicate that ERN1 is an important negative regulator of immunity.

Salmonella invades host cells and replicates inside acidified, remodeled vacuoles that are exposed to reactive oxygen species (ROS) generated by the innate immune response. Oxidative products of the phagocyte NADPH oxidase mediate antimicrobial activity, in part, by collapsing the ΔpH of intracellular Salmonella. Given the role of arginine in bacterial resistance to acidic pH, we screened a library of 54 single-gene mutants in Salmonella that are each involved in, but do not entirely block, arginine metabolism. We identified several mutants that affected Salmonella virulence in mice. The triple mutant ΔargCBH, which is deficient in arginine biosynthesis, was attenuated in immunocompetent mice, but recovered virulence in phagocyte NADPH oxidase deficient Cybb-/- mice. Furthermore, ΔargCBH Salmonella was profoundly susceptible to the bacteriostatic and bactericidal effects of hydrogen peroxide. Peroxide stress led to a larger collapse of the ΔpH in ΔargCBH mutants than occurred in wild-type Salmonella. The addition of exogenous arginine rescued ΔargCBH Salmonella from peroxide-induced ΔpH collapse and killing. Combined, these observations suggest that arginine metabolism is a hitherto unknown determinant of virulence that contributes to the antioxidant defenses of Salmonella by preserving pH homeostasis. In the absence of phagocyte NADPH oxidase-produced ROS, host cell-derived l-arginine appears to satisfy the needs of intracellular Salmonella. However, under oxidative stress, Salmonella must additionally rely on de novo biosynthesis to maintain full virulence.

Mitochondrial calcium uniporter (MCU) is a conserved calcium ion (Ca2+) transporter in the mitochondrial inner membrane of eukaryotic cells. How MCU proteins regulate Ca2+ flow and modulate plant cell development remain largely unclear. Here, we identified the gene GhMCU4 encoding a MCU protein that negatively regulates plant development and fiber elongation in cotton (Gossypium hirsutum). GhMCU4 expressed constitutively in various tissues with the higher transcripts in elongating fiber cells. Knockdown of GhMCU4 in cotton significantly elevated the plant height and root length. The calcium signaling pathway was significantly activated and calcium sensor genes, including Ca2+ dependent modulator of interactor of constitutively active ROP (GhCMI1), calmodulin like protein (GhCML46), calcium-dependent protein kinases (GhCPKs), calcineurin B-like protein (GhCBLs), and CBL-interacting protein kinases (GhCIPKs), were dramatically upregulated in GhMCU4-silenced plants. Metabolic processes were preferentially enriched, and genes related to regulation of transcription were upregulated in GhMCU4-silenced plants. The contents of Ca2+ and H2O2 were significantly increased in roots and leaves of GhMCU4-silenced plants. Fiber length and Ca2+ and H2O2 contents in fibers were significantly increased in GhMCU4-silenced plants. This study indicated that GhMCU4 plays a negative role in regulating cell elongation in cotton, thus expanding understanding in the role of MCU proteins in plant growth and development.

Objectives As the variety and quantity of recalcitrant pollutants such as pharmaceuticals, pesticides, endocrine disruptors, and cosmetic products discharged into water bodies steadily increase, the need for AOPs following biological wastewater treatment processes is growing. In this study, we compared the Total Organic Carbon (TOC) removal capabilities of conventional AOPs, ultrasound, hydrogen peroxide, and persulfate-based multiple AOPs on the final effluent of S wastewater treatment plant. The study also evaluated the feasibility of wastewater reuse by examining the optimal operating conditions of the applied AOPs. Methods The removal characteristics of TOC were investigated based on reaction time, US frequency, and oxidant dosage for the following conditions: ultrasound (US) alone, individual treatments with hydrogen peroxide (H2O2) and persulfate (PS) as oxidants, combined US/H2O2 and US/PS dual AOPs, and a US/PS/H2O2 multi-AOPs system. Results and Discussion Only US oxidation treatment at 80 kHz for 60 minutes resulted in a 14.4% TOC removal efficiency. Individual treatment with H2O2 at 174 mM showed 69.2% removal efficiency, while persulfate oxidation treatment at 43.5 mM showed 13.8%. The PS/H2O2 oxidation treatment showed 68.5% removal efficiency at 174 mM H2O2 and 0.52 mM PS, and an 85.3% removal efficiency at 2.08 mM PS and 350 mM H2O2 conditions. Under the same 80 kHz ultrasound conditions, the combined US and other oxidant treatment resulted in an increased TOC removal efficiency: 87.8% for US/H2O2 at 174 mM H2O2, and 81.9% for US/PS at 43.5 mM PS. Additionally, the multi-treatment with US, PS, and H2O2 showed a removal efficiency of 87.0% at 2.08 mM PS and 350 mM H2O2, and 91.1% at 174 mM H2O2 and 0.52 mM PS conditions. Conclusion In this study, among the AOPs, the oxidation treatment with US/PS/H2O2 exhibited the highest TOC removal efficiency at 91.1%. The integration of chemical oxidants with US demonstrated significant improvement in TOC removal capabilities, with PS showing superior performance at the same concentration conditions among the utilized chemical oxidants in the multi-AOPs. Although H2O2 also displayed commendable TOC removal abilities, its oxidation efficiency was lower at low concentration injections, whereas higher concentrations of H2O2 injections proved to be more effective in oxidation.

Abstract The development of environmentally friendly catalysts for organic transformations is of great importance in the field of green chemistry. Aldehyde oxidation reactions play a crucial role in various industrial processes, including the synthesis of pharmaceuticals, agrochemicals, and fine chemicals. This paper presents the synthesis and evaluation of a new metallosalen carbon nitride catalyst named Co(salen)@g-C3N4. The catalyst was prepared by doping salicylaldehyde onto carbon nitride, and subsequently, incorporating cobalt through Schiff base chemistry. The Co(salen)@g-C3N4 catalyst was characterized using various spectroscopic techniques including Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD), Infrared Spectroscopy (IR), and Thermogravimetric Analysis (TGA). Furthermore, after modification with salicylaldehyde, the carbon nitride component of the catalyst exhibited remarkable yields (74–98%) in oxidizing various aldehyde derivatives (20 examples) to benzoic acid. This oxidation reaction was carried out under mild conditions and resulted in short reaction times (120–300 min). Importantly, the catalyst demonstrated recyclability, as it could be reused for five consecutive runs without any loss of activity. The reusable nature of the catalyst, coupled with its excellent yields in oxidation reactions, makes it a promising and sustainable option for future applications.

Introduction: Streptococcus pneumoniae is the most common cause of bacterial meningitis and meningoencephalitis in humans. The bacterium produces numerous virulence determinants; among them, hydrogen peroxide (H2O2) and pneumolysin (Ply) contribute to bacterial cytotoxicity. Microglia, the resident phagocytes in the brain, are distinct from other macrophages, and we thus compared their susceptibility to pneumococcal toxicity and their ability to phagocytose pneumococci with those of bone-marrow-derived macrophages (BMDMs). Methods: Microglia and BMDMs were co-incubated with S. pneumoniae D39 to analyze the survival of phagocytes by fluorescence microscopy, bacterial growth by quantitative plating, and phagocytosis by an antibiotic protection assay. Ply was detected by hemolysis assay and Western blot analysis. Results: We found that microglia were killed during pneumococcal infection with a wild-type and an isogenic ply-deficient mutant, whereas the viability of BMDMs was not affected by pneumococci. Treatment with recombinant Ply showed a dose-dependent cytotoxic effect on microglia and BMDMs. However, high concentrations of recombinant Ply were required, and under the chosen experimental conditions, Ply was not detectable in the supernatant during infection of microglia. Inactivation of H2O2 by exogenously added catalase abolished its cytotoxic effect. Consequently, infection of microglia with pneumococci deficient for the pyruvate oxidase SpxB, primarily producing H2O2, resulted in reduced killing of microglia. Conclusion: Taken together, in the absence of Ply, H2O2 caused cell death in primary phagocytes in concentrations produced by pneumococci.

Background: Due to the COVID-19 pandemic, several associations worldwide have been recommending the use of 1% hydrogen peroxide solution as a preprocedural mouth rinse before dental treatments to reduce viral load in saliva. This protocol is also employed in stress studies, especially in the context of dental treatment that uses salivary biomarkers as an indicator. However, the effect of 1% hydrogen peroxide as mouth rinse on salivary biomarkers remains unclear. Objective: This study aims to investigate the effects of 1% hydrogen peroxide solution as a preprocedural mouth rinse on 3 salivary stress biomarkers—salivary cortisol, salivary secretory IgA, and salivary α-amylase—both on chemical influence and mechanical irrigation. Materials and methods: Ninety healthy participants with confirmed negative Reverse Transcription Polymerase Chain Reaction results for COVID-19 at most 2 days prior to the experiment were included in this study. All participants were randomly allocated into 3 groups: experimental (1% hydrogen peroxide solution), positive control (distilled water), and negative control (no mouth rinse). Saliva samples were collected before and after mouth rinsing with the respective solutions. Salivary biomarkers were analysed using specific enzyme-linked immunosorbent assay kits. Results: Salivary cortisol and salivary α-amylase did not significantly differ before and after rinsing, whilst salivary sIgA levels decreased in all 3 groups. Nonetheless, there were no significant differences in the changes of these biomarkers across the 3 groups. Conclusions: This study shows that using 1% hydrogen peroxide solution as a preprocedural mouth rinse for universal precaution does not alter the levels of these 3 salivary biomarkers.

The extraction and decolorization conditions for Spirulina platensis polysaccharides using hot alkali and hydrogen peroxide were investigated, and the process was optimized. Based on the results of a single-factor test, the yield and decolorization rate of polysaccharides were taken as indices to optimize the technological conditions for extracting polysaccharides from Spirulina platensis using the hot alkali method and decolorizing them with hydrogen peroxide using the response surface methodology. The optimal conditions for hot alkali extraction of polysaccharides from Spirulina platensis were determined as follows: NaOH concentration of 1.5%, extraction temperature of 90 ℃, extraction time of 4 hours, and material-to-liquid ratio of 1:20 g/mL. Under these conditions, the yield of polysaccharides from Spirulina platensis was 5.18%±0.23%. The optimal conditions for decolorization using hydrogen peroxide were found to be: 17% hydrogen peroxide solution, decolorization time of 55 minutes, and decolorization temperature of 50 ℃. Under these conditions, the actual decolorization rate was 82.54%±0.03%, and the retention rate of polysaccharides was 83.45%±0.13%. The findings of this study provide valuable insights for the development and utilization of Spirulina platensis polysaccharides.

Research into next-generation propellants with green fuel–oxidizer pairs to replace the currently used highly toxic hydrazine–N2O4 system has attracted widespread attention. Ionic liquids (ILs) and hydrogen peroxide have demonstrated their feasibility as a green fuel and an oxidizer, respectively. However, the realisation of effective auto-ignition is the key problem. In this study, a new strategy to trigger the auto-ignition of ILs fuels with hydrogen peroxide by using a unique copper-containing liquid as the promoter is developed. The copper-containing promoter is designed such that its cationic structure is similar to that of the ILs fuels. Based on the principle of “like dissolves like,” the fuel and promoter can be miscible at any ratio to eventually form a catalytic fuel. In addition, the physicochemical properties (e.g. density, viscosity and decomposition temperature) and performance parameters (e.g. ignition delay time and specific impulse) of the as-prepared catalytic fuel are completely characterised. Owing to their excellent hypergolic performance with a short ignition delay time of 16 ms, in combination with the advantages of simple preparation, perfect solubility and green characteristics, the catalytic fuel–oxidizer pair demonstrates promise as bipropellants for rocket applications.

Purpose: The application of natural organic compounds without harmful environmental effects in the production of horticultural and agricultural products is considered as a new method to reduce waste before and after harvesting, increase the storage life and maintain antioxidant activity in developed agriculture. As regards, this study investigated the impact of foliar applications of brown macroalga extract on antioxidant enzyme activity and mineral uptake in 'Hayward' kiwifruits. Research method: Four treatment levels of brown macroalga extract (0, 1, 2, and 3 g/L) were applied at three distinct phases, occurring 110, 125, and 140 days after full bloom. Fruit samples were stored at 1±0.5°C with 95% relative humidity for 90 days, with measurements taken every 30 days. Findings: Results revealed that the 3 g/L extract treatment significantly increased the uptake of calcium (47.82 %), nitrogen (20.52 %), potassium (12.06 %), phosphorus (19.81 %), and iron (25.77 %) compared to the control. The extract demonstrated a substantial effect on all recorded traits. Among the applied treatments, 3 g/L of brown macroalga extract concentration had the best effect in reducing electrolyte leakage (25.10%), malondialdehyde accumulation (96.73%), hydrogen peroxide content (54.54%) and increasing activities of antioxidant enzymes including superoxide dismutase (50.42%), catalase (84.90%), ascorbate peroxidase (79.02%), and peroxidase (49.40%) compared to the control in 90 days of storage. Research limitations: No limitations were found. Originality/Value: The results suggest that the 3 g/L brown macroalga extract concentration holds promise for enhancing the quality of 'Hayward' kiwifruits.

Da-Sol Kim,1,2,&ast; Nam-Gyu Jo,3,&ast; Dong-Won Lee,4,5 Myoung-Hwan Ko,1,2 Jeong-Hwan Seo,1,2 Gi-Wook Kim1,2,4 1Department of Physical Medicine & Rehabilitation, Jeonbuk National University Medical School, Jeonju, Republic of Korea; 2Research Institute of Clinical Medicine of Jeonbuk National University-Biomedical Research Institute of Jeonbuk National University Hospital, Jeonju, Republic of Korea; 3Department of Physical Medicine and Rehabilitation, Hansol Convalescence Rehabilitation Hospital, Jeonju, Republic of Korea; 4Department of Bionanotechnology and Bioconvergence Engineering, Jeonbuk National University, Jeonju, Republic of Korea; 5Department of Polymer Nano Science and Technology, Jeonbuk National University, Jeonju, Republic of Korea&ast;These authors contributed equally to this workCorrespondence: Gi-Wook Kim, Department of Physical Medicine & Rehabilitation, Jeonbuk National University Medical School, Geonjiro 20, Deokjin-gu, Jeonju, Jeonbuk, 54907, Republic of Korea, Tel +82-63-259-3144, Fax +82-10-254-4145, Email k26@jbnu.ac.krPurpose: Peripheral nerve damage lacks an appropriate diagnosis consistent with the patient’s symptoms, despite expensive magnetic resonance imaging or electrodiagnostic assessments, which cause discomfort. Ultrasonography is valuable for diagnosing and treating nerve lesions; however, it is unsuitable for detecting small lesions. Poly(vanillin-oxalate) (PVO) nanoparticles are prepared from vanillin, a phytochemical with antioxidant and anti-inflammatory properties. Previously, PVO nanoparticles were cleaved by H2O2 to release vanillin, exert therapeutic efficacy, and generate CO2 to increase ultrasound contrast. However, the role of PVO nanoparticles in peripheral nerve lesion models is still unknown. Herein, we aimed to determine whether PVO nanoparticles can function as contrast and therapeutic agents for nerve lesions.Methods: To induce sciatic neuritis, rats were administered a perineural injection of carrageenan using a nerve stimulator under ultrasonographic guidance, and PVO nanoparticles were injected perineurally to evaluate ultrasonographic contrast and therapeutic effects. Reverse transcription-quantitative PCR was performed to detect mRNA levels of pro-inflammatory cytokines, ie, tumor necrosis factor-α, interleukin-6, and cyclooxygenase-2.Results: In the rat model of sciatic neuritis, PVO nanoparticles generated CO2 bubbles to increase ultrasonographic contrast, and a single perineural injection of PVO nanoparticles suppressed the expression of tumor necrosis factor-α, interleukin-6, and cyclooxygenase-2, reduced the expression of F4/80, and increased the expression of GAP43.Conclusion: The results of the current study suggest that PVO nanoparticles could be developed as ultrasonographic contrast agents and therapeutic agents for nerve lesions.Keywords: neuroinflammation, ultrasonography, contrast media, polymer nanoparticles, hydrogen peroxide

Recently, there has been a rapid growth in the use of nanoparticles in water treatment processes. However, an important task is to study the toxicity of the materials used and the reaction products formed. The purpose of this study was to evaluate the impact of the proposed water treatment method on the ecosystem. Algae are excellent model organisms for studying the toxic effects of catalyst nanoparticles. This work investigates the toxicity of cobalt ferrite (CoFe2O4) and hydrogen peroxide (H2O2) on the microalgae Chlorella vulgaris Beij. (C. vulgaris). The growth rate of C. vulgaris depends on the residual concentration of H2O2, indicating a stressful physiological state of the microalgae. Exposure to sintered cobalt ferrite granules does not affect the growth of freshwater algae. At a residual H2O2 concentration of 11.9 mM, algal cells' morphology, membrane integrity, and viability were severely impaired. Hydrogen peroxide is known to cause oxidative stress, as evidenced by a decrease in the growth rate of C. vulgaris and an increase in the number of dead cells. The study showed that the high residual concentration of H2O2 is the main obstacle to the discharge of treated water into the natural ecosystem.

Abstract Soft carbon has been recognized as a promising anode material for potassium-ion batteries (PIBs), due to low cost, high conductivity and low voltage platform. However, their practical application is hampered by slow storage kinetics and unsatisfactory cycle life. In this work, pitch-derived needle coke, a typical soft carbon, was incorporated with oxygenated functional groups through liquid phase oxidation by using H2O2 oxidant. When used as anode materials for PIBs, the oxidized needle coke delivers a high reversible capacity of 322.7 mAh g−1, significantly superior to that of the needle coke (237.9 mAh g−1). The enhanced electrochemical performance can be attributed to the abundant oxygenated functional groups and resultant defects on the surface of oxidized needle coke, which not only serve as extra active sites for potassium storage, but also provide sufficient pathways for K+ migration across the adjacent carbon layers. Moreover, the expanded interlayer spacing derived from H2O2 oxidation facilitates rapid K+ intercalation and deintercalation. This work offers an effective modification strategy for the fabrication of high-performance pitch-based soft carbon anodes for PIBs. Graphical Abstract

Lightweight porous geopolymers are a widely researched system with diverse engineering applications. This study presents a comparative investigation on the strength and pore structure characteristics (including pore size distribution, porosity, morphology and pore wall structure) of porous geopolymers with the same densities (0.60, 0.75 and 0.90 g/cm3) synthesized using pre-foaming (PFG) and H 2 O 2 foaming (HFG) methods for the first time. Various techniques, such as XCT, SEM and MIP, were used to characterise their pore structure at multiple scales. The experimental results demonstrate that PFG exhibits slightly higher compressive strength compared to that of HFG with the same density, which is attributed to the relatively lower macro-pore porosity and more uniform micron-scale (>10 μm) pore structure. Moreover, there are more micron-scale pores and less small capillaries and gel pores (<100 nm) in HFG compared to PFG. Stable foam bubbles can be introduced directly into fresh geopolymers through the pre-foaming method, whereas H 2 O 2 foaming results in the formation of a more unevenly distributed porous system through the decomposition of hydrogen peroxide and the merging of bubbles. This study serves to deepen the comprehension of the foaming process and underlying mechanisms of these two foaming methods, offering new valuable insights into fabricating porous geopolymers with target pore structures in specific engineering applications. [ABSTRACT FROM AUTHOR]

Monoolein cubic phase incorporating poly(dimethylaminoethyl methacrylate-co-phenyl vinyl sulfide) (P(DMAEMA-co-PVS)) and indocyanine green (ICG, a photosensitizer) was prepared as a multiple-responsive carrier. P(DMAEMA-co-PVS), prepared by a free radical polymerization, was air/water interface-active and it exhibited lower critical solution temperature (LCST). The polymer increased in its LCST by H2O2 treatment, possibly because of the hydrolytic detachment of DMAEMA pendant, evidenced by 1H NMR and FT-IR spectroscopy. Water channels surrounded by lipid matrix, characteristic of cubic phase, was observed on TEM photos and the inclusion of the additives (e.g., P(DMAEMA-co-PVS) had little effect on the structure. The cubic phases increased their thermal stability upon the inclusion of the polymer chains and they maintained their integrity once the temperature was kept below 60 °C, supported by the polarized optical microscopy and the differential scanning calorimetry. The release of a cargo (i.e., fluorescent dextran) was suppressed at body temperature (37 °C) at the H2O2 concentration of normal tissue (e.g., 0.000002%), possibly due to an entangled network structure formed by the thermally induced inter/intramolecular hydrophobic interaction of the polymer chains. The release was markedly promoted at the H2O2 concentration of tumor tissue (e.g., 0.0034%), possibly because the thermally induced hydrophobic interaction can be weakened by the hydrolytic degradation. In addition, the release was significantly enhanced by NIR irradiation. The cubic phase would be used as a drug carrier which releases its payload at a target site in a selected manner in answering to H2O2 and NIR irradiation. [ABSTRACT FROM AUTHOR]

[Display omitted] The rational design of efficient photocatalysts to achieve artificial nitrogen fixation is an urgent challenge. Herein, we combined donor–acceptor covalent organic framework with iron-doped nitrogen vacancy graphitized carbon nitride (D-A COF/Fe-g-C 3 N x) for photocatalytic nitrogen fixation. The photocatalyst exhibited good crystallinity, high porosity, and a large specific surface area. Without a sacrificial agent, the optimal 40 % D-A COF/Fe-g-C 3 N x exhibited an excellent rate of ammonia production (646 μmol h−1 g−1) at 420 nm, and durable stability after successive cycling. Exhaustive experimental research and theory calculations verified that the D-A unit and Fe doping redistributed the distribution of the charge, which enhanced the visible light utilization and provided chemisorption sites for further polarization. Besides N -vacancies can serve as electron-trapping active sites to promote the directional migration of carriers. The reaction mechanism demonstrated that superoxide radical and hydrogen peroxide were formed by electron and hole, respectively, which promote the reduction of nitrogen to ammonia. This work provides a new idea for the rationalizing design of efficient catalysts for photocatalytic nitrogen fixation under mild conditions. [ABSTRACT FROM AUTHOR]

Drought has a direct impact on rice growth performance at various stages. Nevertheless, the impact of nanoparticles on the rice seedlings under drought stress remained limited. Thus, a laboratory experiment was conducted to investigate the effects of different concentrations (300, 600, and 900 mg/L) of silica nanoparticles (SiNPs) on morpho-histological and biochemical features of two rice varieties (UMT-R and MR219) under drought stress (15 % PEG). The findings indicated a substantial reduction due to drought stress in the growth, protein, and antioxidant enzymes, while increasing the proline, malondialdehyde (MDA), and hydrogen peroxide (H 2 O 2) content, and negatively affecting the root histology. Results showed that SiNPs at 600 mg/L were managed to improve plant growth, root vigour, and enzymatic antioxidant levels. Under SiNPs treated plants, among UMT-R and MR219, the proline (1.947 and 1.748 in leaves, 2.010 and 1.890 U/mg protein in roots), peroxidase (POD) (2.850 and 3.512 in leaves, 2.521 and 2.952 U/mg protein in roots), superoxide dismutase (SOD) (3.958 and 4.558 in leaves, 4.296 and 4.606 U/mg protein in roots), and catalase (CAT) (2.171 and 2.289 in leaves, 1.897 and 2.050 U/mg protein in roots) were higher than the drought stress conditions. Meanwhile, the nonenzymatic antioxidant, MDA (0.974 and 0.812 in leaves, 0.842 and 0.778 U/mg Protein in roots), and H 2 O 2 (1.378 and 1.229 in leaves, 1.280 and 1.054 U/mg Protein in roots) showed an opposite trend. SiNPs application noticeably enhanced the histological features of roots under drought conditions. The current findings suggested that SiNPs at 600 mg/L can mitigate the adverse impacts of drought stress and enhance the plant's resistance. Further study should be carried out on the reproductive stage and post-harvest performance of drought-stress rice treated with SiNPs. [Display omitted] • SiNPs treatment significantly increased plant growth under drought conditions. • SiNPs have a significant effect on the root histological traits. • SiNPs significantly enhance protein, proline, SOD, POD, and CAT content. • UMT-R was more sensitive to drought stress as compared to MR219. [ABSTRACT FROM AUTHOR]

Wheat is affected by various biotic and abiotic stresses, especially salinity, which reduces the growth and yield drastically. High salinity is a major constraint for wheat productivity in many countries, including Bangladesh. With this view, here, an experiment was conducted to observe genotypic differences in physiological, ion accumulation, agro-morphological and yield performance of wheat against different levels of salinity. Experimental variables consisted of five salt tolerant genotypes (G 20–2–2, G 20–1–2, G 13–2, G 22–2, G 9–2), one susceptible genotype (G 24–2) and one standard check variety (BARI ghom 25), which assigned to four levels of salinity with electrical conductivities control (0.3), 4, 8 and 12 dS m −1. Irrespective of genotypes, salinity stress significantly decreased the yield and yield attributes. Results of analyses based on salt tolerance indices of plant growth related and yield contributing parameters, ionic balance (Na+, K + and Na+ / K + ratio), and stress indicators such as chlorophyll content, photosynthetic rate (Pn), stomatal conductance (gs) and transpiration rate (Tr) revealed genotypes G 20–2–2, G 13–2 and G 20–1–2 as salt tolerant, genotype G 9–2 as moderately salt-tolerant and G 24–2 and G 22–2 as salt-sensitive genotypes. Additionally, lower accumulations of hydrogen peroxide and malondialdehyde, and higher activities of antioxidant enzymes in the salt-tolerant genotypes G 20–2–2 and G 13–2 than in the salt-sensitive genotype G 24–2 indicated reduced oxidative damage in genotypes G 20–2–2 and G 13–2 relative to that in genotype G 24–2. Collectively, our findings suggest that the optimum growth and yield of salt tolerant genotypes are associated with decreased Na+/ K + ratio, increased antioxidant enzymes activity and reduced oxidative stress. [Display omitted] [ABSTRACT FROM AUTHOR]

Key message: CitCAT1 and CitCAT2 were cloned and highly expressed in mature leaves. High temperatures up-regulated CitCAT1 expression, while low temperatures and Diversispora versiformis up-regulated CitCAT2 expression, maintaining a low oxidative damage. Catalase (CAT), a tetrameric heme-containing enzyme, removes hydrogen peroxide (H2O2) to maintain low oxidative damage in plants exposed to environmental stress. This study aimed to clone CAT genes from Citrus sinensis cv. “Oita 4” and analyze their expression patterns in response to environmental stress, exogenous abscisic acid (ABA), and arbuscular mycorrhizal fungal inoculation. Two CAT genes, CitCAT1 (NCBI accession: PP067858) and CitCAT2 (NCBI accession: PP061394) were cloned, and the open reading frames of their proteins were 1479 bp and 1539 bp, respectively, each encoding 492 and 512 amino acids predicted to be localized in the peroxisome, with CitCAT1 being a stable hydrophilic protein and CitCAT2 being an unstable hydrophilic protein. The similarity of their amino acid sequences reached 83.24%, and the two genes were distantly related. Both genes were expressed in stems, leaves, flowers, and fruits, accompanied by the highest expression in mature leaves. In addition, CitCAT1 expression was mainly up-regulated by high temperatures (37 °C), exogenous ABA, and PEG stress within a short period of time, whereas CitCAT2 expression was up-regulated by exogenous ABA and low-temperature (4 °C) stress. Low temperatures (0 °C) for 12 h just up-regulated CitCAT2 expression in Diversispora versiformis-inoculated plants, and D. versiformis inoculation up-regulated CitCAT2 expression, along with lower hydrogen peroxide and malondialdehyde levels in mycorrhizal plants at low temperatures. It is concluded that CitCAT2 has an important role in resistance to low temperatures as well as mycorrhizal enhancement of host resistance to low temperatures. [ABSTRACT FROM AUTHOR]

In the past few decades, the overuse of antibiotics has been a growing concern in the field of medicine. To address this issue, there has been increasing interest in the development of efficient treatment methods. Recently, research has shown that the modification of iron oxychloride with Mn, Co, or Ni can significantly enhance its performance in the degradation of tetracycline hydrochloride. This is attributed to the high similarity between Mn, Co, Ni and Fe, bimetallic systems can be constructed to improve the accelerated cycle of M(II)–M(III) and the activation of hydrogen peroxide, peroxymonosulfate and peroxydisulfate. Additionally, active substances such as SO4−·, ·OH, and 1O2 have been identified in the PS system, while ·OH and 1O2 are active in the H2O2 system. In this study, due to the presence of these active substances, the degradation rate of tetracycline hydrochloride within 10 min in three different systems such as hydrogen peroxide can reach 100%. These findings offer promising prospects for the development of more effective and sustainable treatment methods for antibiotic pollution. [ABSTRACT FROM AUTHOR]

The direct epoxidation of mixed ethene and propene feedstocks using hydrogen peroxide over a titanium silicalite (TS-1) catalyst was investigated within a continuous trickle bed reactor operating in laboratory scale. Methanol was employed as the reaction solvent. This study aimed to streamline the epoxidation process by obviating the need for prior separation of alkenes, thereby enhancing process efficiency. An extensive array of operational parameters was explored in a trickle bed reactor, encompassing experimental parameters such as temperature, total pressure, hydrogen peroxide concentration, liquid flow rate, and gas composition. In contrast to prior investigations involving separate ethene and propene epoxidation, this study revealed a reduction in epoxide selectivity. The principal by-products observed were methoxy species, formed through the interaction between the epoxide and methanol, resulting in a ring-opening reaction. The influence of water on this ring-opening process was negligible. Notably, the tunability of the system was demonstrated, highlighting low temperature and elevated partial ethene pressure as pivotal factors for augmentingthe epoxide selectivity. The findings suggest that binary olefin mixtures exhibit diminished selectivity but improved stability. This behavior is potentially linked to the olefin solubility in methanol, or alterations in the surface species concentrations, typically associated with catalyst activity variations. These insights offer a valuable foundation for understanding and optimizing the direct epoxidation of mixed ethene and propene feedstock. [ABSTRACT FROM AUTHOR]

Okra is a vegetable that stands out for its low production cost, high yield, high nutritional and value and socioeconomic importance in income generation, especially in family farming. In this context, the present study evaluated the physiology, production and water use efficiency of okra under irrigation with saline water and exogenous application of hydrogen peroxide. The treatments were distributed in a randomized block design, in a 5 × 3 factorial arrangement, with five levels of electrical conductivity of irrigation water - ECw (0.3; 1.3; 2.3; 3.3 and 4.3 dS m-1) and three concentrations of hydrogen peroxide - H2O2 (0, 25 and 50 µM), with five replicates, totaling 75 plants. Irrigation with ECw above 0.3 dS m-1 negatively affected stomatal conductance, transpiration, number of fruits, total production and water use efficiency of okra cv. Clemson Americano 80. Hydrogen peroxide at concentration of 22 µM mitigated the effects of salt stress on CO2 assimilation rate, number of fruits, average fruit weight and total production of okra cv. Clemson Americano 80. Water use efficiency is favored by H2O2 application at concentration of 12 µM, especially in plants irrigated with ECw of 0.3 dS m-1. [ABSTRACT FROM AUTHOR]

Objective: To evaluate the effect of COVID-19 preventive mouthwashes on the surface hardness, surface roughness (Ra), and color change (ΔE) of three different polymer-based composite CAD/CAM materials (Vita Enamic (ENA), Grandio Block (GB), Lava Ultimate (LU)). Methods: A total of 100 rectangular-shaped specimens with dimensions of 2 mm × 7 mm × 12 mm were obtained by sectioning three different CAD/CAM blocks and randomly divided into five subgroups according to the 30 days of mouthwash immersion protocol as follows: Control: artificial saliva, PVP-I: 1% povidone-iodine, HP: 1.5% hydrogen peroxide, CPC: mouthwash containing 0.075% cetylpyridinium chloride, EO: mouthwash containing essential oils. Microhardness, Ra, and ΔE values were measured at baseline and after 30 days of immersion protocols. Data were analyzed using the Wald Chi-square, two-way ANOVA, and post hoc Tukey tests. Results: The independent factors (materials and solutions) significantly influenced the microhardness and color (p < 0.001). Ra of the materials was not affected by any of the mouthwashes (p > 0.05). The microhardness and color of each material varied significantly after immersion in PvP-I and HP (p < 0.05). The highest percentage change in microhardness, Ra, and ΔE was found in LU immersed in PvP-I and HP mouthwashes, while the lowest change was found in ENA groups (p < 0.05). Conclusion: Within the limitations of this study, it was found that the surface hardness and color of tested polymer-based composite CAD/CAM materials are susceptible to degradation and change after 30 days of immersion in 1% PvP-I and 1.5% HP mouthwashes. [ABSTRACT FROM AUTHOR]

Advanced oxidation processes are the most efficient tool to thwart the overaccumulation of harmful organic compounds in the environment. In this direction bioinspired metal complexes may be a viable solution for oxidative degradations in water. However, their synthesis is often elaborated and their scalability consequently low. This study presents alternative easy-to-synthesize bioinspired metal complexes to promote degradations in water. The metals employed were iron and manganese ions, hence cheap and highly accessible ions. The complexes were tested toward Phenol, Estrone, Triclosan, Oxybenzone, Diclofenac, Carbamazepine, Erythromycin, Aspartame, Acesulfame K, Anisole and 2,4-Dinitrotoluene. The reaction favoured electron-rich compounds reaching a removal efficiency of over 90%. The central ion plays a crucial role. Specifically, Mn(II) induces a non-radical pathway while iron ions a predominant radical one (⋅OH is predominant). The iron systems resulted more versatile toward contaminants, while the manganese ones showed a higher turn-over number, hence higher catalytic behaviour. [ABSTRACT FROM AUTHOR]

Constructing stable and efficient photocatalysts for H2O2 production is of great importance and is challenging. In this study, the synthesis of three photoactive cyclooctatetrathiophene (COTh)‐based porous aromatic frameworks (COTh‐PAFs) in an alternating donor‐acceptor (D−A) fashion is presented. In combination with a triazine‐derived electron acceptor, PAF‐363 exhibits high efficiency for the photosynthesis of H2O2 with production rates of 11733 μmol g−1 h−1(with sacrificial agent) and 3930 μmol g−1 h−1 (without sacrificial agent) from water and oxygen under visible light irradiation. Experimental results and theoretical calculations reveal that the charge transfer positions and the O2 adsorption sites in PAF‐363 are both concentrated on COTh fragments, which facilitate the H2O2 production through the oxygen reduction reaction (ORR) pathway. This work highlights that the rational design of COTh‐PAFs with consideration of D−A direction, charge transfer positions, and O2 adsorption sites provides a feasible access to efficient H2O2 production photocatalysts. [ABSTRACT FROM AUTHOR]

Ordered hexagonal mesoporous aluminophosphate and its cobalt‐substituted analogue were successfully synthesized using ionic liquid as a structure‐directing agent. The resulting materials were systematically characterized by various analytical, spectroscopic, and imaging methods, confirming the presence of divalent cobalt in the tetrahedral framework of the matrix. Further, the high surface area, pore volume, and thicker mesopore walls of these materials impart good thermal and hydrothermal stability. The mesoporous catalysts showed excellent activity towards the oxidation of cyclohexane reactions using hydrogen peroxide as an oxidant, with 98.5 % conversion and 90.4 % selectivity towards cyclohexanol. [ABSTRACT FROM AUTHOR]

Different strains of Escherichia coli that exhibit genetic characteristics linked to diarrhea pose a major threat to both human and animal health. The purpose of this study was to determine the prevalence of pathogenic Escherichia coli (E. coli), the genetic linkages and routes of transmission between E. coli isolates from different animal species. The efficiency of disinfectants such as hydrogen peroxide (H2O2), Virkon®S, TH4+, nano zinc oxide (ZnO NPs), and H2O2-based zinc oxide nanoparticles (H2O2/ZnO NPs) against isolated strains of E. coli was evaluated. Using 100 fecal samples from different diarrheal species (cow n = 30, sheep n = 40, and broiler chicken n = 30) for E. coli isolation and identification using the entero-bacterial repetitive intergenic consensus (ERIC–PCR) fingerprinting technique. The E. coli properties isolated from several diarrheal species were examined for their pathogenicity in vitro. Scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HR-TEM), Fourier-transform infrared spectrum (FT-IR), X-ray diffraction (XRD), zeta potential, and particle size distribution were used for the synthesis and characterization of ZnO NPs and H2O2/ZnO NPs. The broth macro-dilution method was used to assess the effectiveness of disinfectants and disinfectant-based nanoparticles against E. coli strains. Regarding the results, the hemolytic activity and Congo red binding assays of pathogenic E. coli isolates were 55.3 and 44.7%, respectively. Eleven virulent E. coli isolates were typed into five ERIC-types (A1, A2, B1, B2, and B3) using the ERIC-PCR method. These types clustered into two main clusters (A and B) with 75% similarity. In conclusion, there was 90% similarity between the sheep samples' ERIC types A1 and A2. On the other hand, 89% of the ERIC types B1, B2, and B3 of cows and poultry samples were comparable. The H2O2/ZnO NPs composite exhibits potential antibacterial action against E. coli isolates at 0.04 mg/ml after 120 min of exposure. [ABSTRACT FROM AUTHOR]

Neutrophil extracellular traps (NETs) are defense mechanisms that trap and kill microorganisms and degrade cytokines. However, excessive production, dysregulation of suppression mechanisms, or inefficient removal of NETs can contribute to increased inflammatory response and the development of pathological conditions. Therefore, research has focused on identifying drugs that inhibit or delay the NET release process. Since reactive oxygen species (ROS) play a significant role in NET release, we aimed to investigate whether resveratrol (RSV), with a wide range of biological and pharmacological properties, could modulate NET release in response to different stimuli. Thus, human neutrophils were pretreated with RSV and subsequently stimulated with PMA, LPS, IL-8, or Leishmania. Our findings revealed that RSV reduced the release of NETs in response to all tested stimuli. RSV decreased hydrogen peroxide levels in PMA- and LPS-stimulated neutrophils, inhibited myeloperoxidase activity, and altered the localization of neutrophil elastase. RSV inhibition of NET generation was not mediated through A2A or A2B adenosine receptors or PKA. Based on the observed effectiveness of RSV in inhibiting NET release, our study suggests that this flavonoid holds potential as a candidate for treating NETs involving pathologies. [ABSTRACT FROM AUTHOR]

Overproduction of reactive oxygen species (ROS), metal ion accumulation, and tricarboxylic acid cycle collapse are crucial factors in mitochondria‐mediated cell death. However, the highly adaptive nature and damage‐repair capabilities of malignant tumors strongly limit the efficacy of treatments based on a single treatment mode. To address this challenge, a self‐reinforced bimetallic Mito‐Jammer is developed by incorporating doxorubicin (DOX) and calcium peroxide (CaO2) into hyaluronic acid (HA) ‐modified metal‐organic frameworks (MOF). After cellular, Mito‐Jammer dissociates into CaO2 and Cu2+ in the tumor microenvironment. The exposed CaO2 further yields hydrogen peroxide (H2O2) and Ca2+ in a weakly acidic environment to strengthen the Cu2+‐based Fenton‐like reaction. Furthermore, the combination of chemodynamic therapy and Ca2+ overload exacerbates ROS storms and mitochondrial damage, resulting in the downregulation of intracellular adenosine triphosphate (ATP) levels and blocking of Cu‐ATPase to sensitize cuproptosis. This multilevel interaction strategy also activates robust immunogenic cell death and suppresses tumor metastasis simultaneously. This study presents a multivariate model for revolutionizing mitochondria damage, relying on the continuous retention of bimetallic ions to boost cuproptosis/immunotherapy in cancer. [ABSTRACT FROM AUTHOR]

Electrosynthesis of H2O2 via both pathways of anodic two-electron water oxidation reaction (2e-WOR) and cathodic two-electron oxygen reduction reaction (2e-ORR) in a diaphragm-free bath can not only improve the generation rate and Faraday efficiency (FE), but also simplify the structure of the electrolysis bath and reduce the energy consumption. The factors that may affect the efficiency of H2O2 generation in coupled electrolytic systems have been systematically investigated. A piece of fluorine-doped tin oxide (FTO) electrode was used as the anode, and in this study, its catalytic performance for 2e-WOR in Na2CO3/NaHCO3 and NaOH solutions was compared. Based on kinetic views, the generation rate of H2O2 via 2e-WOR, the self-decomposition, and the oxidative decomposition rate of the generated H2O2 during electrolysis in carbonate electrolytes were investigated. Furthermore, by choosing polyethylene oxide-modified carbon nanotubes (PEO-CNTs) as the catalyst for 2e-ORR and using its loaded electrode as the cathode, the coupled electrolytic systems for H2O2 generation were set up in a diaphragm bath and in a diaphragm-free bath. It was found that the generated H2O2 in the electrolyte diffuses and causes oxidative decomposition on the anode, which is the main influent factor on the accumulated concentration in H2O2 in a diaphragm-free bath. [ABSTRACT FROM AUTHOR]

Poly(ionic liquid) (PIL)‐based porous membranes are extensively investigated as soft polymer actuators. While PILs have shown significant advancements in membrane fabrication and stabilization of metal nanoparticles (MNPs), research on integrating MNPs into porous membranes to achieve actuation behavior under multiple stimuli is limited. Herein, this work presents a new paradigm for designing a porous PIL‐polyacrylic acid (PAA) membrane with a distinct MNP gradient via a top‐bottom diffusion approach involving a metal salt precursor solution and NaBH4 as a reducing agent. The strong binding sites provided by PILs, combined with the gradient distribution of ‐COO− groups across the membrane cross‐section, play a significant role in controlling the MNPs' gradient distribution. Interestingly, the MNPs within the membrane display excellent catalytic activity in exothermic reactions such as H2O2 decomposition, dissipating uneven heat that quickly permeates the membrane network. This induces asymmetrical swelling of polymer chains, resulting in rapid membrane bending. Furthermore, such MNP‐loaded membrane could serve as a portable test paper for visually monitoring H2O2. This advancement paves the way for the development of intricate smart actuation materials and expands their practical applications in various real‐life scenarios. [ABSTRACT FROM AUTHOR]

Early‐stage responses of Brassica juncea, B. napus and B. oleracea during black spot disease and the development of Alternaria brassicicola were evaluated. Infection of plant cells by the fungus occurred mainly through direct penetration or by appressoria and, rarely, stomata in B. juncea and B. oleracea; in B. napus, penetration was mostly direct. The process of conidial germination, germ tubes and appressoria formation on a leaf surface was correlated with the post‐inoculation time and host species (p < 0.05). Changes in the leaf surface were observed at successful infection sites as bright, wax‐deprived areas. Significant differences in progression of infection between Brassica species were observed, with B. oleracea being the most susceptible and B. napus the least. Accumulation of superoxide anion radicals and hydrogen peroxide was not only observed in plant cells, but also in A. brassicicola germ tubes and appressoria at 8 and 12 h post‐inoculation (hpi). Enhanced production of reactive oxygen species (ROS) and lipid peroxidation during infection triggered diverse patterns of enzymatic and non‐enzymatic antioxidant activities and phenolic compound contents in response to A. brassicicola. In each Brassica species, a different antioxidant was the most active. With their antioxidant properties, phenolic compounds also played an essential role in these interactions. This phenomenon could be related to the disparate levels of susceptibility of the Brassica species to A. brassicicola; for example, the most susceptible, B. oleracea, showed high ROS accumulation with decreasing tendency during disease progression, unchanged phenolics content, and the highest catalase activity, differentiating it from B. juncea and B. napus. [ABSTRACT FROM AUTHOR]

Considering the application prospects of a cascade catalytic system in biomedical analysis, it remains significant to develop a cascade catalytic system for one-step rapid colorimetric detection. Herein, PVP/NH2-MIL-101(Fe) possessing enhanced peroxidase (POD)-like activity was successfully synthesized by microwave-assisted and polyvinylpyrrolidone (PVP) modification strategies. Then, PVP/NH2-MIL-101(Fe) and glucose oxidase (GOx) were covalently coupled via the bifunctional cross-linker glutaraldehyde, the GOx@PVP/NH2-MIL-101(Fe) with dual enzymatic functional activities (POD-like and GOx activities) was subsequently synthesized. GOx@PVP/NH2-MIL-101(Fe) had strong affinities for the substrates glucose, 3,3',5,5'-tetramethylbenzidine, and hydrogen peroxide. Based on this specific nanozyme GOx@PVP/NH2-MIL-101(Fe), a one-step colorimetric assay for rapid glucose determination was built. This detection method not only took 20 min to analyze but also possessed a linear range of 10–250 µM with a detection limit of 1.05 µM. Furthermore, the cascade catalytic system was applied to determine glucose concentrations in human serum samples. Compared with commercial blood glucose meters, the proposed method was also accurate and effective, making it a candidate method for determining blood glucose. [ABSTRACT FROM AUTHOR]

The modified carbon nitride nanozyme could realize biomimetic catalysis application for evaluation of total antioxidant capacity via self-cascade photocatalytic H 2 O 2 production. [Display omitted] The peroxidase mimics usually requires the addition of exogenous hydrogen peroxide (H 2 O 2), which greatly hinder their practical applications. Herein, through rational co-modification of multiple elements (potassium (K), chlorine (Cl) and iodine (I)), the modified carbon nitride nanomaterials (KCl/KI-CN) could serve as efficient bifunctional catalysts. The multiple elements doping and the incorporation of cyano groups (C N) are deemed to enhance their photocatalytic and peroxidase-like activity, respectively. Based on the photocatalytic function, H 2 O 2 can be produced continuously and steadily via two-electron oxygen reduction over modified carbon nitride under visible light irradiation. Subsequently, the KCl/KI-CN could catalyze the chromogenic substrate by the in-situ produced H 2 O 2. Taking advantage of the bifunctional properties of modified carbon nitride, we for the first time demonstrate a self-cascade catalytic process and apply successfully for the ascorbic acid (AA) detection and versatile total antioxidant capacity (TAC) evaluation. This paper not only prepares an efficiently bifunctional catalyst but also provides a new self-cascade photocatalytic H 2 O 2 production strategy for the peroxidase-like application. [ABSTRACT FROM AUTHOR]

The development of environmentally friendly catalysts for organic transformations is of great importance in the field of green chemistry. Aldehyde oxidation reactions play a crucial role in various industrial processes, including the synthesis of pharmaceuticals, agrochemicals, and fine chemicals. This paper presents the synthesis and evaluation of a new metallosalen carbon nitride catalyst named Co(salen)@g-C3N4. The catalyst was prepared by doping salicylaldehyde onto carbon nitride, and subsequently, incorporating cobalt through Schiff base chemistry. The Co(salen)@g-C3N4 catalyst was characterized using various spectroscopic techniques including Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD), Infrared Spectroscopy (IR), and Thermogravimetric Analysis (TGA). Furthermore, after modification with salicylaldehyde, the carbon nitride component of the catalyst exhibited remarkable yields (74–98%) in oxidizing various aldehyde derivatives (20 examples) to benzoic acid. This oxidation reaction was carried out under mild conditions and resulted in short reaction times (120–300 min). Importantly, the catalyst demonstrated recyclability, as it could be reused for five consecutive runs without any loss of activity. The reusable nature of the catalyst, coupled with its excellent yields in oxidation reactions, makes it a promising and sustainable option for future applications. [ABSTRACT FROM AUTHOR]

Iron nanoparticles, with low toxicity and many active sites, are among the materials that not only reduce waste along with green chemistry but also increase the separation power and recover the catalyst from the reaction environment. In this study, first, the surface of iron nanoparticles was silanized, and in the next step, the complex of chitosan HCl.VO3 was placed on the surface of Fe3O4 (Fe3O4@SiO2@CSH+VO3−). This nanocatalyst is a novel, recoverable, and potent nanocatalyst with high selectivity for the oxidation of sulfides to sulfoxides. Various physicochemical techniques such as IR, XRD, TGA, SEM, EDX, mapping, TEM, and VSM were used to affirm the well synthesis of the catalyst. Oxidation of sulfides in the presence of hydrogen peroxide as a green oxidant and in ethanol was catalyzed by the Fe3O4@SiO2@CSH+VO3−. All sulfoxides were achieved with high efficiency and in a short time. The notable privileges of this method include facile and economic catalyst synthesis, proper catalyst durability, great performance, simple catalyst isolation, good recovery capability, at least up to 5 times without an index drop in catalytic power. [ABSTRACT FROM AUTHOR]

The results reported herein demonstrate for the first time that typical reducing agents in an alkaline medium initiate chemiluminescence of luminol in the presence of hemin, and the efficiency of their action is comparable to that of hydrogen peroxide and exceeds it in the case of the superoxide anion. The pertinent implications of these findings refer to new possibilities for developing chemiluminescence assays and biosensors and to precautions for determining hydrogen peroxide using luminol and hemin in samples of unknown composition, most prominently, of biological origin. [ABSTRACT FROM AUTHOR]

The Zr‐monosubstituted phosphotungstate (Bu4N)8[{PW11O39Zr(μ‐OH)(H2O)}2] (1) is a highly active and selective catalyst for thioether sulfoxidation with aqueous H2O2 in acetonitrile or acetonitrile/ethanol. The reaction proceeds unprecedentedly fast and completes within seconds at room temperature. Various sulfides produce corresponding sulfoxides with selectivity of 98–99 % and oxidant utilization efficiency of 92–99 %. The reaction mechanism was investigated using test substrates, kinetic, isotopic labeling, and spectroscopic tools. The oxidation of thianthrene‐5‐oxide and competitive sulfide‐sulfoxide oxidation point to an electrophilic oxidation mechanism, but a V‐shaped Hammett plot found for oxidation of p‐substituted thioanisoles may suggest a biphilic nature of active species. Kinetic studies revealed that the rate‐limiting step of the reaction is the interaction of a peroxo zirconium intermediate with organic substrates. ATR‐FT‐IR and 31P NMR spectroscopic studies coupled with stoichiometric experiments indicated that peroxo species capable of transferring an oxygen atom to thioethers are dimeric side‐on mono‐ and diperoxo complexes, [Zr2(μ‐η2 : η2‐O2){PW11O39}2(H2O)x]]8− (I) and [{Zr(μ‐η2‐O2)}2(PW11O39)2(H2O)y]10− (II), and monomeric Zr‐hydroperoxo [Zr(η2‐OOH)PW11O39]4− (III) and peroxo [Zr(η2‐O2)PW11O39]5− (IV) species, which dominate at high excess of H2O2. While I and III are endowed with electrophilic oxygen, which can be transferred to electron‐rich sulfides, more negatively charged II and IV preferably react with thioethers comprising electron‐withdrawing substituents. [ABSTRACT FROM AUTHOR]