Peroxidation Products Research Articles

Solar-Driven Hydrogen Peroxide Production via BiVO4-Based Photocatalysts.

Solar hydrogen peroxide (H2O2) production has garnered increased research interest owing to its safety, cost-effectiveness, environmental friendliness, and sustainability. The synthesis of H2O2 relies mainly on renewable resources such as water, oxygen, and solar energy, resulting in minimal waste. Bismuth vanadate (BiVO4) stands out among various oxide semiconductors for selective H2O2 production under visible light via direct two-electron oxygen reduction reaction (ORR) and two-electron water oxidation reaction (WOR) pathways. Significant advancements have been achieved using BiVO4-based materials in solar H2O2 production over the last decade. This review explores advancements in BiVO4-based photocatalysts for H2O2 production, focusing on photocatalytic powder suspension (PS) and photoelectrochemical (PEC) systems, representing the main approaches for heterogenous artificial photosynthesis. An overview of fundamental principles, performance assessment methodologies, photocatalyst and photoelectrode development, and optimization of reaction conditions is provided. While diverse strategies, such as heterojunction, doping, crystal facet engineering, cocatalyst loading, and surface passivation, have proven effective in enhancing H2O2 generation, this review offers insights into their similar and distinct implementations within the PS and PEC systems. The challenges and future prospects in this field are also discussed to facilitate the rational design of high-performing BiVO4-based photocatalysts and photoelectrodes for H2O2 generation under visible light.

Balancing Activity and Selectivity in Two-electron Oxygen Reduction through First Coordination Shell Engineering in Cobalt Single Atom Catalysts.

The electrochemical two-electron oxygen reduction reaction (2e- ORR) offers a potentially cost-effective and eco-friendly route for the production of hydrogen peroxide (H2O2). However, the competing 4e- ORR that converts oxygen to water limits the selectivity towards hydrogen peroxide. Accordingly, achieving highly selective H2O2 production under low voltage conditions remains challenging. Herein, guided by first-principles density functional theory (DFT) calculations, we show that modulation the first coordination sphere in Co single atom catalysts (Co-N-C catalysts with Co-NxO4-x sites), specifically the replacement of Co-N bonds with Co-O bonds, can weaken the *OOH adsorption strength to boost the selectivity towards H2O2 (albeit with a slight decrease in ORR activity). Further, by synthesizing a series of N-doped carbon-supported catalysts with Co-NxO4-x active sites, we were able to validate the DFT findings and explore the trade-off between catalytic activity and selectivity for 2e- ORR. A catalyst with trans-Co-N2O2 sites exhibited excellent catalytic activity and H2O2 selectivity, affording a H2O2 production rate of 12.86 [[EQUATION]]and an half-cell energy-efficiency of 0.07 [[EQUATION]] during a 100-h H2O2 production test in a flow-cell.

Balancing Activity and Selectivity in Two‐electron Oxygen Reduction through First Coordination Shell Engineering in Cobalt Single Atom Catalysts

The electrochemical two‐electron oxygen reduction reaction (2e‐ ORR) offers a potentially cost‐effective and eco‐friendly route for the production of hydrogen peroxide (H2O2). However, the competing 4e‐ ORR that converts oxygen to water limits the selectivity towards hydrogen peroxide. Accordingly, achieving highly selective H2O2 production under low voltage conditions remains challenging. Herein, guided by first‐principles density functional theory (DFT) calculations, we show that modulation the first coordination sphere in Co single atom catalysts (Co‐N‐C catalysts with Co‐NxO4‐x sites), specifically the replacement of Co‐N bonds with Co‐O bonds, can weaken the *OOH adsorption strength to boost the selectivity towards H2O2 (albeit with a slight decrease in ORR activity). Further, by synthesizing a series of N‐doped carbon‐supported catalysts with Co‐NxO4‐x active sites, we were able to validate the DFT findings and explore the trade‐off between catalytic activity and selectivity for 2e‐ ORR. A catalyst with trans‐Co‐N2O2 sites exhibited excellent catalytic activity and H2O2 selectivity, affording a H2O2 production rate of 12.86 [[EQUATION]]and an half‐cell energy‐efficiency of 0.07 [[EQUATION]] during a 100‐h H2O2 production test in a flow‐cell.

Mechanistic insights into allosteric regulation of the reductase component of p-hydroxyphenylacetate 3-hydroxylase by p-hydroxyphenylacetate: a model for effector-controlled activity of redox enzymes.

Understanding how an enzyme regulates its function through substrate or allosteric regulation is crucial for controlling metabolic pathways. Some flavin-dependent monooxygenases (FDMOs) have evolved an allosteric mechanism to produce reduced flavin while minimizing the use of NADH and the production of harmful hydrogen peroxide (H2O2). In this work, we investigated in-depth mechanisms of how the reductase component (C1) of p-hydroxyphenylacetate (HPA) 3-hydroxylase (HPAH) from Acinetobacter baumanii is allosterically controlled by the binding of HPA, which is a substrate of its monooxygenase counterpart (C2). The C1 structure can be divided into three regions: the N-terminal domain (flavin reductase); a flexible loop; and the C-terminal domain, which is homologous to NadR, a repressor protein having HPA as an effector. The binding of HPA to NadR induces a conformational change in the recognition helix, causing it to disengage from the NadA gene. The HPA binding site of C1 is located at the C-terminal domain, which can be divided into five helices. Molecular dynamics simulations performed on HPA-docked C1 elucidated the allosteric mechanism. The carboxylate group of HPA maintains the salt bridge between helix 2 and the flexible loop. This maintenance shortens the loop between helices 2 and 3, causing helix 3 to disengage from the N-terminal domain. The aromatic ring of HPA induces a conformational change in helices 1 and 5, pulling helix 4, analogous to the recognition helix in NadR, away from the N-terminal domain. A Y189A mutation, obtained from site-saturation mutagenesis, confirms that HPA with an unsuitable conformation cannot induce the conformational change of C1. Additionally, an HPA-independent effect is observed, in which Arg20, an NADH binding residue on the N-terminal domain, occasionally disengages from helix 4. This model provides valuable insights into the allosteric regulation of two-component FDMOs and aromatic effector systems.

Pseudomonas aeruginosa biofilm decontamination and removal by Ar/H2O cold atmospheric plasma in endoscope-like tubing

Abstract In medical device disinfection, removing bacteria and biofilms is challenging due to the poor penetration of detergents into the biofilm matrix. This is specifically true for endoscopes, which cannot be fully sterilized. This paper presents a new technique for decontaminating and removing P. aeruginosa biofilm from endoscope tubing using cold atmospheric plasma (CAP). The CAP is produced everywhere inside a contaminated tube under sustained Ar/H2O flow. The tube arrangement mimics the working channel environment of an endoscope, which is particularly difficult to sterilize. The discharge’s chemical activity was optimized by increasing the voltage without increasing the total power, which enhanced the production of hydroxyl radicals (OH) and hydrogen peroxide (H2O2). The disinfection treatment was tested on 24 h grown biofilm using the crystal violet assay for biofilm removal and the regrowth assay for bacterial decontamination. The treatments demonstrated effective decontamination capabilities at all treatment times with no bacterial regrowth. Etching of the biofilm sample by OH radicals was observed. After 30 min of treatment, only 18 ± 4% of biofilm remained on the surface, indicating near-complete biofilm removal and total absence of bacterial regrowth. This preliminary study demonstrates the effectiveness of using the direct contact of an Ar/H2O plasma to decontaminate and remove biofilm from complex shapes, such as flexible polytetraethylene tubes. It has the potential to enhance and shorten the disinfection of medical equipment, such as endoscopes.

Mechanisms for the Production and Suppression of Hydrogen Peroxide at the Hydrogen Electrode in Proton Exchange Membrane Fuel Cells and Water Electrolyzers: Theoretical Considerations

Hydrogen peroxide is inevitably produced at the hydrogen electrode in both the proton exchange membrane fuel cell (PEMFC) and the proton exchange membrane water electrolyzer (PEMWE) when platinum-based catalysts are used. This peroxide attacks and degrades the membrane, seriously limiting its lifetime. Here we review some of our previous efforts to suppress peroxide production using PtFe as a hydrogen evolution reaction (HER) catalyst and PtCo as a hydrogen oxidation reaction (HOR) catalyst. The mechanisms, which involve the chemical reaction of adsorbed hydrogen with oxygen, are examined using density functional theory. The onset of excess peroxide production at 0.1 V above the reversible potential has not been adequately explained thus far, and therefore a new mechanism is proposed here. This involves a unique reaction site including hydrogen adsorbed at (110) step edges adjacent to (111) terraces on the Pt surface, as well as on Pt alloys and other metals such as Rh and Ir. This mechanism helps explain the recent finding of the Wadayama group that Ir single crystal surfaces such as Ir(111) and Ir(110) produce little peroxide during the HOR. It also points the way toward the design of new catalysts for the hydrogen electrode that suppress peroxide production while retaining high HOR and HER activity.

Unsymmetric Protonation Driven Highly Efficient H2O2 Photosynthesis in Supramolecular Photocatalysts via One‐Step Two‐Electron Oxygen Reduction

AbstractPhotocatalytic hydrogen peroxide (H2O2) production has emerged as an attractive alternative to the traditional anthraquinone process. However, its performance is often hindered by low selectivity and sluggish kinetics of oxygen reduction reaction (ORR). Herein, we report an anthrazoline‐based supramolecular photocatalyst, SA‐SADF‐H+, featuring an unsymmetric protonation structure for H2O2 photosynthesis from water and air. The introduction of unsymmetric protonation disrupts the initial mirror symmetry of SADF, significantly enhancing the molecular dipole and facilitating efficient charge separation and electron transfer. Additionally, this modification increases the hydrophilicity of SA‐SADF‐H+, enabling the interaction of water and dissolved oxygen with the catalytic sites. The altered electron density distribution creates numerous dual active sites for Yeager‐type O2 adsorption, facilitating an efficient ORR towards H2O2 via a direct one‐step two‐electron pathway. Notably, SA‐SADF‐H+ achieves an outstanding photocatalytic H2O2 production at a rate of 4666.7 μmol L−1 h−1, with a remarkable solar‐to‐chemical conversion (SCC) of 1.35 %, surpassing most organic photocatalytic systems. Furthermore, SA‐SADF‐H+ demonstrates remarkable photocatalytic antibacterial activity, achieving 100 % antibacterial efficiency against Staphylococcus aureus within 60 min.

Design of a novel complex 99mTc-Nilutamide as a tracer for prostate cancer disorder detection in mice

Abstract Male prostate cancer (PCa) is considered among the most fatal illnesses. Despite the recent decrease in prostate cancer incidence attributed to advancements in early detection and therapy, these reductions have not effectively mitigated the elevated fatality rate linked to this disease. The drug Nilutamide was effectively radiolabeled with technetium-99m, producing a radiochemical yield of 96 ± 0.14 % under optimal conditions. In our study, two cohorts of mice were utilized, namely the control group and the group with prostate cancer. Various biochemical parameters, including PSA levels in serum, were assessed, revealing a significantly elevated value in the group with prostate cancer, indicating potential tumor development. Furthermore, the activities of antioxidant enzymes (CAT, SOD) were notably lower in the group with prostate cancer compared to the healthy control group, while the oxidative activity reflected by MDA levels, the final product of lipid peroxidation, was higher in the prostate cancer group than in the healthy control group. The biodistribution analysis showed rapid localization of 99mTc-Nilutamide in prostate cancer tissue after 2 h post-injection, with a substantial value of 11.4 ± 1.1 % I. D/g tissue. Consequently, it was deduced that radiolabeled 99mTc-Nilutamide can serve as an effective imaging tool for prostate cancer.

Efficient Hydrogen Peroxide Production: Enhancing Electron Transfer on PANI/ CdS Photocatalysts in Aqueous Solution

The conventional anthraquinone process for hydrogen peroxide production is energy-intensive and complex. We present a sustainable alternative: a photocatalytic technology driven by solar energy for the green and efficient generation of H2O2. In this study, we synthesized polyaniline (PANI), a conductive polymer, and combined it with CdS nanoparticles (CdS-NP) using a hydrothermal method to create PANI/CdS-NP composites. The unique hollow raspberry-like structure of the composite enhances light utilization through multiple reflections and refractions. PANI significantly improved the photoresponse and photocatalytic activity of CdS-NP. Under visible light and an air flow of 20mL·min-1, the 10wt%-PANI/CdS-NP composite exhibited a remarkable photocatalytic hydrogen peroxide production rate of 371.33 μmol·h-1·g-1, surpassing the pristine CdS-NP by 1.74 times, and all without any sacrificial agents. Work function calculations revealed that the electron transport between CdS and PANI follows the type II heterojunction photocatalytic mechanism, with the one-step two-electron ORR being the dominant pathway. This work not only contributes to the theoretical understanding of photocatalytic H2O2 synthesis but also offers a promising route toward the green and sustainable production of H2O2.

Chronic gastroesophageal reflux dysregulates proteostasis in esophageal epithelial cells

Background and aimsGastroesophageal reflux disease (GERD) is a common digestive disorder that is characterized by esophageal tissue damage produced by exposure of the esophageal lining to the gastric refluxate. GERD can raise the risk of multiple serious complications including esophageal tumors. At the molecular levels, GERD-affected tissues are characterized by strong oxidative stress and the formation of reactive isolevuglandins (isoLGs). These products of lipid peroxidation rapidly interact with cellular proteins forming protein adducts. Here, we investigated the interrelationship between isoLG adduction and aggregation of cellular proteins. MethodsProtein misfolding and aggregation were analyzed using multiple protein misfolding and aggregation assays. Pathological consequences of protein adduction and aggregation were studied using human and murine esophageal tissues. Surgical model of esophageal reflux injury and L2-IL1β transgenic mice were employed to investigate the mechanisms of protein misfolding and aggregation. ResultsOur studies demonstrate that gastroesophageal reflux causes protein misfolding and aggregation that is associated with severity of GERD. Dysregulation of proteostasis induces ferroptotic cell death and is mediated by modification of cellular proteins with reactive isoLGs that can be prevented by isoLG scavengers. ConclusionsGERD causes dysregulation of cellular proteostasis, accumulation of isoLG protein adducts, misfolded and aggregated proteins that promote ferroptotic cell death. Taken together, this study suggests that GERD has similarities to other known pathological conditions that are characterized by protein misfolding and aggregation.

Cell Cycle Arrest Via DNA Damage Response (DDR) Pathway Induced by Extracellular Self-DNA (esDNA) Application in Rice Root

Conspecific plant growth is inhibited by extracellular fragments in a concentration-dependent manner. Although several reports have addressed this self-DNA inhibition, the underlying mechanism remains unclear. In this investigation, we evaluated the progression of cell cycle of rice roots in responding to extracellular-self DNA (esDNA). We analyzed root growth, hydrogen peroxide (H2O2) production, Catalase (CAT) and Ascorbate Peroxidase (APX) enzyme activities, DNA Damage Response (DDR)-related gene expression, and cell cycle progression. Our results suggest that esDNA-induced root growth inhibition on days 7 and 10 and might associated with cell cycle arrest initiated several hours after esDNA treatment. The esDNA-induced cell cycle arrest is facilitatedthrough the DDR pathway, activated by DNA damage resulting from elevated reactive oxygen species (ROS) induced by esDNA. Specifically, esDNA upregulates DDR-related gene expression including OsATM (Oryza sativa ataxia telangiectasia mutated), OsATR (Oryza sativa ATM and Rad3-related), OsSOG1 (Oryza sativa SUPPRESSOR OF GAMMA RESPONSE 1), OsWEE1 (Oryza sativa WEE1-like kinase 1), and OsSMR4 (Oryza sativa SIAMESE-RELATED 4), leading to cell cycle arrest. Finally, we propose that cell cycle arrest might be a plausible explanation for the phenomenon of root growth inhibition by esDNA. This result highlights the significance of DDR signaling in the plant’s response to esDNA. This finding will be helpful as initial information for developing green herbicides to control monocot weeds in agriculture.

Real-time Neurochemical Sensing of Hydrogen Peroxide Production in Brain Tissue using Advanced Nanostructured Au Microelectrodes Functionalized with Ruthenium Purple Film

Real-time monitoring of H2O2 is essential for understanding its role in neurological physio(path)ology. In this study, we developed an advanced electrochemical sensor utilizing nanostructured gold wire microelectrodes functionalized with a Ruthenium Purple (RP) film, a polynuclear transition metal hexacyanoferrate analog of the prototypical Prussian blue (PB). The RP film exhibits enhanced stability in neutral buffer solutions and reduced interference from biologically relevant cations such as Na+, Mg2+, and Ca2+. By integrating gold nanoparticles onto a nanoporous gold surface, we significantly increased the electroactive surface area of the microwire (ρ=26.1 ± 10.2). The electrodeposition of a thin RP film (4.23 ± 1.2 nm) resulted in a highly selective H2O2 sensor, operating at an optimal potential of -0.05 V vs. Ag/AgCl, with a linear detection range of 0.5-500 µM, sensitivity of 1.18 ± 0.37 µA µM-1 cm-2, and a low limit of detection (LOD) of 66.6 ± 34.9 nM. Adding a Nafion® layer enhanced the sensor's operational stability, maintaining optimal performance over three hours under physiological conditions of pH and ion concentration. We validated the sensor's capability to monitor transient changes in H2O2 concentration in brain tissue by assessing its response to exogenously applied H2O2. Furthermore, we demonstrated that glutamate receptor activation in hippocampal slices induces a rapid and transient increase in extracellular H2O2 levels, underscoring the sensor's potential for studying oxidative stress in neurobiological contexts.

Multifunctional nanocomposites based on kaolinite/titania/iron applied to hydrogen peroxide production and bisphenol–A removal

The rising global demand for hydrogen peroxide, recognized for its eco–friendly properties, underscores the need for greener synthesis methods. Traditional production processes pose environmental risks, while direct synthesis faces challenges like water formation, explosion hazards, and stability issues, limiting industrial application. On the other hand, Bisphenol A (BPA), an endocrine disruptor widely used in plastics, presents significant environmental and health concerns due to its potential leaching into food and water. The present work introduces efficient and selective photocatalysts aimed at sustainable hydrogen peroxide synthesis and BPA degradation. Both processes were enhanced by the synergistic properties of Fe2O3–TiO2 nanoparticles dispersed within a kaolinite matrix. The Fe2O3–TiO2 photocatalysts, characterized by photoluminescence spectroscopy and X–ray diffraction, showed reduced emission upon iron incorporation and anatase presence on the kaolinite surface. The photocatalytic activity was evaluated through hydroxylation of terephthalic acid, revealing a 127 μmol/L min hydroxylation rate for the KaFeTi400 sample. BPA degradation studies indicated optimal performance in acidic conditions, achieving 96 % removal in 2 h and 98 % in 4 h, with the addition of H2O2 enhancing efficiency. Further, the photocatalyst facilitated benzyl alcohol oxidation to benzaldehyde, demonstrating a H2O2 production rate of 120 μmol. These findings highlight the multifunctional capabilities and environmental benefits of the photocatalyst, underscoring its potential for sustainable hydrogen peroxide synthesis and broader applications in environmental remediation. The catalysts address the pressing challenges associated with hydrogen peroxide synthesis and pollutant removal, particularly in the context of sustainability and environmental impact.

Glutathione S-Transferase Contributes to the Resistance of Megalurothrips usitatus Against Lambda-Cyhalothrin by Strengthening Its Antioxidant Defense Mechanisms.

The damage caused by Megalurothrips usitatus, a common pest, has significantly affected the Chinese vegetable industry. The inappropriate application of chemical pesticides has caused M. usitatus to become highly resistant to conventional insecticides. Glutathione S-transferase (GST), known for its multifunctional properties, contributes to detoxification and antioxidation. It enhances insects' adaptability to pesticides by facilitating the elimination of lipid peroxidation products resulting from pyrethroid insecticides. This research employed RT-qPCR to identify GST genes that exhibited significant expression in response to lambda-cyhalothrin stress. It also quantified changes in antioxidant and apoptosis markers within the M. usitatus under lambda-cyhalothrin exposure. The functional significance of GST was validated by assessing alterations in the antioxidant defense system and resistance to lambda-cyhalothrin following the inhibition of GST activity. The study's outcomes indicated that MuGSTs1 was markedly upregulated in response to lambda-cyhalothrin stress (p < 0.0001). The GST activity was effectively suppressed by the specific inhibitor, diethyl maleate, achieving an inhibition rate of 64.05%. Following the inhibition of GST, the overall antioxidant capacity was reduced by 3.1-fold compared with the control, and the M. usitatus exhibited a 7.91-fold increase in sensitivity to lambda-cyhalothrin. These findings confirm the pivotal role of GST in the oxidative stress response of the M. usitatus and their contribution to the development of resistance to lambda-cyhalothrin through enhanced antioxidant defenses. This research offers valuable perspectives on the adaptive reactions of insects to chemical stressors, facilitating the management of resistance and the formulation of effective pest control strategies.

Unsymmetric Protonation Driven Highly Efficient H2O2 Photosynthesis in Supramolecular Photocatalysts via One-Step Two-Electron Oxygen Reduction.

Photocatalytic hydrogen peroxide (H2O2) production has emerged as an attractive alternative to the traditional anthraquinone process. However, its performance is often hindered by low selectivity and sluggish kinetics of oxygen reduction reaction (ORR). Herein, we report an anthrazoline-based supramolecular photocatalyst, SA-SADF-H+, featuring an unsymmetric protonation structure for H2O2 photosynthesis from water and air.The introduction of unsymmetric protonation disrupts the initial mirror symmetry of SADF, significantly enhancing the molecular dipole and facilitating efficient charge separation and electron transfer. Additionally, this modification increases the hydrophilicity of SA-SADF-H+, enabling the interaction of water and dissolved oxygen with the catalytic sites. The altered electron density distribution creates numerous dual active sites for Yeager-type O2 adsorption, facilitating an efficient ORR towards H2O2 via a direct one-step two-electron pathway. Notably, SA-SADF-H+ achieves an outstanding photocatalytic H2O2 production at a rate of 4667 μmol L-1 h-1, with a remarkable solar-to-chemical conversion (SCC) of 1.35%, surpassing most organic photocatalytic systems. Furthermore, SA-SADF-H+ demonstrates remarkable photocatalytic antibacterial activity, achieving 100% antibacterial efficiency against Staphylococcus aureus within 60 min.

Covalent Organic Frameworks with Constrained Palladium Nanoclusters Lock the Enol-Keto Tautomerism Enhancing Hydrogen Peroxide Photosynthesis.

The production of hydrogen peroxide from natural seawater is green and sustainable. However, the efficiency of photocatalytic hydrogen peroxide production is low due to the degradation and poisoning of photocatalysts by the abundant ions in natural seawater. Precisely controlling the structure of photocatalysts to enhance their corrosion resistance and minimize the impact of external particles is a challenging task. Here, a novel molecular engineering strategy is reported in which confined Pd nanoclusters locked keto structures to enhance photocatalytic hydrogen peroxide production. Both experimental and theoretical findings reveals that Pd nanoclusters, when confined within a keto structure, not only bolster the stability of the photocatalyst but also augment the efficiency of photogenerated charge carriers' separation and transport. This dual enhancement significantly boosts the photocatalytic performance for hydrogen peroxide synthesis. One of the photocatalysts, TAPT-2KtTb Pd COF, exhibits an impressive photocatalytic hydrogen peroxide production rate of 2676.3µmol g-1 h-1, which is one of the highest values reported so far. Integral photocatalyzed H2O2 synthesis using confined Pd nanoclusters locked keto conformation COF provides a new insight for developing innovative photocatalysts for H2O2 synthesis.

Mitochondrial respiratory capacity in kidney podocytes is high, age-dependent, and sexually dimorphic.

Whether and how podocytes depend on mitochondria across their long post-mitotic lifespan is yet unclear. With limited cell numbers and broad kidney distribution, isolation of podocyte mitochondria typically requires first isolating podocytes themselves. Disassociation of podocytes from their basement membrane, however, recapitulates an injured state that may stress mitochondria. To address this, we crossed floxed hemagglutinin (HA) -mitochondria tagged (MITO-Tag) mice with those expressing Cre in either podocytes (NPHS2) or distal tubule and collecting duct (CDH16), thus allowing for rapid, kidney cell-specific, isolation of mitochondria via immunoprecipitation. Mitochondrial respiration in fresh isolates from young (4-7 mo) and aged (22-26 mo) mice of both sexes demonstrated several previously unreported significant differences between podocyte and tubule mitochondria. First, although podocytes contain fewer mitochondria than do tubule cells, mitochondria isolated from podocytes averaged twice the respiratory capacity of tubule mitochondria when normalized to mitochondrial content by citrate synthase (CS) levels. Second, age-related decline in respiration was detected only in podocyte mitochondria and only in aged male mice. Finally, disassociating podocytes for cell culture initiates functional decline in mitochondria as those from cultured primary podocytes have half the respiratory capacity, but twice the hydrogen peroxide production of podocyte mitochondria isolated directly from fresh kidneys. Thus, podocytes maintain sexually dimorphic mitochondria with greater oxidative phosphorylation capacity than mitochondria-dependent tubules per organelle. Previous studies may not have detected these differences due to reliance on podocyte cell culture conditions, which results in artifactual suppression of mitochondrial function.

Amorphous Bi-BiOx - inducted directional charges transfer in stalactite-like carbon nitride heterojunction for effective photocatalytic H2O2 production

Photocatalytic technology provides a clean and sustainable method for producing hydrogen peroxide (H2O2), while, the yield is significantly hindered by the rapid recombination of charge carrier and the low oxygen reduction activity of catalyst. Herein, the Bi-BiOx/CN heterojunction was successfully constructed by homogeneously loaded amorphous Bi-BiOx species on stalactite-like CN just via one-step pyrolysis with the pre-coordination confinement strategy. In the Bi-BiOx/CN heterojunction, the Bi-BiOx species acted as electron storage layer and induced electrons directional migrate from CN to Bi-BiOx species, which promoted the carrier separation. Meanwhile, the three-dimensional stalactite structure of CN not only increased the active sites and gas shuttle pores, but also shorten the electrons and holes diffuse distance from the bulk phase to the surface. As expected, the H2O2 generation rate of optimal Bi-BiOx/CN-10 reached 6036 μM/g/h, which is 1.86 times higher than that of CN. The experimental results proved that ·O2– plays an important role in H2O2 production, and the direct 2e- ORR reaction and the indirect 2e- ORR reaction coexist. This work validates the potential of Bi-BiOx species as an alternative to noble metals for heterojunction construction, and provides a feasible path for regulating efficient directional transfer of charge transfer.

Overall photosynthesis of hydrogen peroxide with redox-active catechol moiety by modulating charge behavior of polydopamine-coated engineered carbon nitride

Photocatalytic production of hydrogen peroxide (H2O2) offers an environment-friendly and sustainable route. However, low efficiency and undesirable by-products hinder its large-scale application. A heterostructure (PDA/SCN) by in situ polymerization dopamine on edge functionalized carbon nitride (SCN) has been designed to integrate photoredox and photocatalytic production of hydrogen peroxide with revisable transformation between catechol and o‑benzoquinone. Benefiting from the strong built-in electric field, efficient photoinduced charge separation is disclosed to facilitate the autoxidation of redox-active catechol moiety. In addition, functional groups (–NH2) on the heterostructure, as an interfacial H-bond modulation site, are conductive to optimize the O2 activation and subsequent formation of the key intermediate *OO. Moreover, a homemade gas-solid-liquid triphase flow cell using PDA/SCN photocatalyst with improving mass transfer process has been constructed, which shows a high H2O2 generation of 1.32 mM h–1 under visible light (λ ≥ 420 nm) without using any sacrificial reagent. This photocatalytic system provides a new guidance of efficient photocatalyst design for the synthesis of H2O2 without using any sacrificial reagent.

Synthesis of 1,2,4-Oxadiazin-5(6H)-One Derivatives and Their Biological Investigation as Monoamine Oxidase Inhibitors

Monoamine oxidase (MAO) plays a key role in the pathogenesis of central nervous system disorders, and MAO inhibitors have been used in the treatment of depression and Parkinson’s disease. In the search for new classes of MAO inhibitors, the present study investigated a series of 1,2,4-oxadiazin-5(6H)-one derivatives. This study provides the first optimization of the reaction conditions for the condensation of amidoximes with alkyl 2-halocarboxylates to yield the desired 1,2,4-oxadiazin-5(6H)-ones. The results of the in vitro MAO inhibition studies showed that the 1,2,4-oxadiazin-5(6H)-ones were indeed inhibitors of human MAO with the most potent inhibition observed for 5f (IC50 = 0.900 µM) and 7c (IC50 = 0.371 µM). It was concluded that, with appropriate substitution, 1,2,4-oxadiazin-5(6H)-one derivatives would act as good potency MAO-B inhibitors and lead compounds for the development of antiparkinsonian drugs. In Parkinson’s disease, MAO-B inhibitors enhance central dopamine levels and reduce MAO-mediated production of hydrogen peroxide and resultant oxidative injury. This study represents one of few works to investigate synthetic approaches and biological activities of the 1,2,4-oxadiazin-5(6H)-one class of heterocycles.