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Plants produce reactive oxygen species (ROS) upon infection, which typically trigger defence mechanisms and impede pathogen proliferation. Root-knot nematodes (RKNs, Meloidogyne spp.) represent highly detrimental pathogens capable of parasitizing a broad spectrum of crops, resulting in substantial annual agricultural losses. The involvement of ROS in RKN parasitism is well acknowledged. In this study, we identified a novel effector from Meloidogyne incognita, named CATLe, that contains a conserved catalase domain, exhibiting potential functions in regulating host ROS levels. Phylogenetic analysis revealed that CATLe is conserved across RKNs. Temporal and spatial expression assays showed that the CATLe gene was specifically up-regulated at the early infection stages and accumulated in the subventral oesophageal gland cells of M. incognita. Immunolocalization demonstrated that CATLe was secreted into the giant cells of the host plant during M. incognita parasitism. Transient expression of CATLe significantly dampened the flg22-induced ROS production in Nicotiana benthamiana. In planta assays confirmed that M. incognita can exploit CATLe to manipulate host ROS levels by directly degrading H2O2. Additionally, interfering with expression of the CATLe gene through double-stranded RNA soaking and host-induced gene silencing significantly attenuated M. incognita parasitism, highlighting the important role of CATLe. Taken together, our results suggest that RKNs can directly degrade ROS products using a functional catalase, thereby manipulating host ROS levels and facilitating parasitism.

To facilitate our understanding of proteome dynamics during signaling events, robust workflows affording fast time resolution without confounding factors are essential. We present Surface-exposed protein Labeling using PeroxidaSe, H2O2, and Tyramide-derivative (SLAPSHOT) to label extracellularly exposed proteins in a rapid, specific, and sensitive manner. Simple and flexible SLAPSHOT utilizes recombinant soluble APEX2 protein applied to cells, thus circumventing the engineering of tools and cells, biological perturbations, and labeling biases. We applied SLAPSHOT and quantitative proteomics to examine the TMEM16F-dependent plasma membrane remodeling in WT and TMEM16F KO cells. Time-course data ranging from 1 to 30 min of calcium stimulation revealed co-regulation of known protein families, including the integrin and ICAM families, and identified proteins known to reside in intracellular organelles as occupants of the freshly deposited extracellularly exposed membrane. Our data provide the first accounts of the immediate consequences of calcium signaling on the extracellularly exposed proteome.

To oxidize trace concentrations of organic contaminants under conditions relevant to surface- and groundwater, air-diffusion cathodes were coupled to stainless-steel cathodes that convert atmospheric O2 into hydrogen peroxide (H2O2), which then was activated to produce hydroxyl radicals (·OH). By separating H2O2 generation from its activation and employing a flow-through electrode consisting of stainless-steel fibers, the two processes could be operated efficiently in a manner that overcame mass-transfer limitations for O2, H2O2, and trace organic contaminants. The flexibility resulting from separate control of the two processes made it possible to avoid both the accumulation of excess H2O2 and the energy losses that take place after H2O2 has been depleted. The decrease in treatment efficacy occurring in the presence of natural organic matter was substantially lower than that typically observed in homogeneous advanced oxidation processes. Experiments conducted with ionized and neutral compounds indicated that electrostatic repulsion prevented negatively charged ·OH scavengers from interfering with the oxidation of neutral contaminants. Energy consumption by the dual-cathode system was lower than values reported for other technologies intended for small-scale drinking water treatment systems. The coordinated operation of these two cathodes has the potential to provide a practical, inexpensive way for point-of-use drinking water treatment.

Rapid and precise detection of hydrogen peroxide (H2O2) holds great significance since it is linked to numerous physiological and inorganic catalytic processes. We herein developed a label-free and washing-free strategy to detect H2O2 by employing a hand-held personal glucose meter (PGM) as a signal readout device. By focusing on the fact that the reduced redox mediator ([Fe(CN)6]4-) itself is responsible for the final PGM signal, we developed a new PGM-based strategy to detect H2O2 by utilizing the target H2O2-mediated oxidation of [Fe(CN)6]4- to [Fe(CN)6]3- in the presence of horseradish peroxidase (HRP) and monitoring the reduced PGM signal in response to the target amount. Based on this straightforward and facile design principle, H2O2 was successfully determined down to 3.63 μM with high specificity against various non-target molecules. We further demonstrated that this strategy could be expanded to identify another model target choline by detecting H2O2 produced through its oxidation promoted by choline oxidase. Moreover, we verified its practical applicability by reliably determining extracellular H2O2 released from the breast cancer cell line, MDA-MB-231. This work could evolve into versatile PGM-based platform technology to identify various non-glucose target molecules by employing their corresponding oxidase enzymes, greatly advancing the portable biosensing technologies.

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]

We developed a sensing strategy that mimics the bead-based electrogenerated chemiluminescence immunoassay. However, instead of the most common metal complexes, such as Ru or Ir, the luminophore is luminol. The electrogenerated chemiluminescence of luminol was promoted by in situ electrochemical generation of hydrogen peroxide at a boron-doped diamond electrode. The electrochemical production of hydrogen peroxide was achieved in a carbonate solution by an oxidation reaction, while at the same time, microbeads labelled with luminol were deposited on the electrode surface. For the first time, we proved that was possible to obtain light emission from luminol without its direct oxidation at the electrode. This new emission mechanism is obtained at higher potentials than the usual luminol electrogenerated chemiluminescence at 0.3–0.5 V, in conjunction with hydrogen peroxide production on boron-doped diamond at around 2–2.5 V (vs Ag/AgCl). [ABSTRACT FROM AUTHOR]

AuPt@MnO 2 nanoplatform with CAT/POD/Gox-like activities was constructed for NIR-II photothermal-promoted catalytic therapy. [Display omitted] Bimetallic nanozymes exhibited multi-enzyme activities, but glutathione (GSH) overexpression and weak catalytic capability restricted their catalytic therapeutic performance. Thus, this study developed a smart nanozyme (AuPt@MnO 2) with a core–shell structure by coating manganese dioxide (MnO 2) on the gold-platinum (AuPt) nanozyme (AuPt@MnO 2) surface to enhance catalytic therapy. In this nanozyme, AuPt possessed triple-enzyme activities, i.e., catalase, peroxidase, and glucose oxidase, which greatly improved oxygen, hydroxyl radicals (·OH), and hydrogen peroxide generation, due to cyclic reactions. Moreover, GSH consumption degraded the MnO 2 shell, which then enhanced ·OH generation of Mn2+. More importantly, the near-infrared-II (NIR-II) photothermal performance of AuPt@MnO 2 with a high conversion efficiency of 38.7 % further promoted multi-enzyme activities and enhanced catalytic therapy. Moreover, combining NIR-II photothermal therapy and enhancing catalytic therapy decreased the cell viability to 10.8 %, and thereby, the tumors were cleared. Thus, the AuPt@MnO 2 smart nanoplatform developed in this study exhibited NIR-II photothermal-promoted multi-enzyme activities and excellent antitumor efficacy, which will be promising for enhancing catalytic therapy. [ABSTRACT FROM AUTHOR]

[Display omitted] In tumor therapy, copper (Cu)-based nanozymes with peroxidase-like activity play a crucial role in converting hydrogen peroxide into hydroxyl radicals (OH). This process induces immunogenic cell death, which in turn activates the body's immune response, enhancing the efficacy of tumor immunotherapy. Nonetheless, the efficiency of this reaction is curtailed due to the oxidation of Cu(I) to Cu(II), leading to the self-depletion of the nanozyme's activity and an insufficient yield of OH for effective immunotherapeutic activation. To surmount this challenge, our research introduces a photocharging self-doped semiconductor nanozyme, copper sulfide (Cu 9 S 8). The photocharging effect enables the nanozyme to convert internal Cu(II) back to Cu(I) through charge transfer induced by near-infrared (NIR)-II photothermal energy, thereby effectively maintaining the enzyme-like activity of the nanozyme. Additionally, Cu 9 S 8 is enhanced with a calcium sulfide (CaS) coating. This coating reacts in the acidic microenvironment of tumors to generate hydrogen sulfide (H 2 S) gas, which in turn suppresses the catalase activity inherent in tumor cells, ensuring a plentiful supply of H 2 O 2 for the nanozyme's operation. This dual strategy of amplifying enzyme-like activity and substrate availability culminates in the generation of ample OH within tumor cells, leading to significant immunogenic cell death and thereby realizing potent immunotherapy. [ABSTRACT FROM AUTHOR]

[Display omitted] Hydrogen peroxide (H 2 O 2) is a crucial eco-friendly oxidizer with increasing demand due to its wide range of applications. Activating O 2 with catalysts to generate H 2 O 2 on-site offers a promising alternative to traditional production methods. Here, we design unique crystalline/amorphous heterophase Fe-Mn core–shell chains (ZVI-Mn) for efficient on-site generation of H 2 O 2 and manipulation of subsequent H 2 O 2 activation. The yield of H 2 O 2 on-site produced by ZVI-Mn in water within 5 min was 103.7 mg·L-1, which was much greater than that of zero-valent iron (ZVI) and amorphous Mn (A-Mn) (0 and 42.5 mg·L-1). Raman and density functional theory (DFT) calculations confirmed that *OOH is the key species involved in the on-site generation of H 2 O 2. Electrochemical tests confirmed the excellent electron-transferring ability, while electron paramagnetic resonance (EPR) revealed oxygen vacancy defects in the catalysts, which proved to be conducive to improving the catalytic activity of ZVI-Mn. Additionally, by regulating the pH of aqueous solution, ZVI-Mn can simultaneously achieve efficient on-site generation of H 2 O 2 and in-situ removal of enrofloxacin from aqueous solution. [ABSTRACT FROM AUTHOR]

Zeolite imidazole framework −8 (ZIF-8) was used as the encapsulation layer to improve the stability and activity of ZnO nanoparticles. Under the voltage of 2.0 V vs.RHE, the stability test could be carried out for 60 h, and the yield of H 2 O 2 did not decrease significantly. [Display omitted] A promising method of producing hydrogen peroxide (H 2 O 2) is the electrochemical two-electron water oxidation reaction (2e− WOR). In this process, it is important to design electrocatalysts that are both earth abundant and environmentally friendly, as well as offering high stability and production rates. The research of WOR catalysts, such as the extensively used transition metal oxides, is mainly focused on the modification of transition metal elements. Few studies pay attention to the protective heterostructure of metal oxides. Here, we demonstrate for the first time an organometallic skeleton protection strategy to develop highly stable WOR catalysts for H 2 O 2 generation. Unlike the pure ZnO and zeolite imidazole framework-8 (ZIF-8) catalysts, ZnO@ZIF-8 enabled the production of hydrogen peroxide at high voltages. The experimental results demonstrate that the ZnO@ZIF-8 catalyst stably generates H 2 O 2 even under a high voltage of 3.0 V vs. RHE, with a yield reaching 2845.819 μmolmin−1 g−1. ZnO@ZIF-8 shows a relatively low overpotential, with a current density of 10 mA cm−2 and an overpotential of 110 mV. The ZnO@ZIF-8 catalyst's maximal FE value was 4.72 %. Moreover, the ZnO@ZIF-8 catalyst exhibits remarkable durability even after an extended 60-hour stability test. Operando Raman and theoretic calculation analyses reveal that the metal–organic skeleton being encapsulated on the metal oxide surface synergizes with each other, not only expanding the electrochemical surface area, but also adjusting the catalyst metal sites' adsorption capacity. A novel approach to the modification of 2e− WOR metal oxide catalyst is presented in this work. [ABSTRACT FROM AUTHOR]

A comparative study of composites based on imidazolium phosphomolybdates of the SILP type of catalysts for peroxide oxidative desulfurization was performed by mass spectrometry and other physicochemical methods, in particular, XPS (X-ray photoelectron spectroscopy). An analysis of the data obtained revealed partial destruction of heteropolyanions during the synthesis of heterogeneous samples. The results of mass spectrometric measurements are well correlated with the XPS data, indicating the possibility of using mass spectrometry (MS) in the surface-activated laser desorption/ionization (SALDI) technique for characterization of these composites. The results of the analysis of the desulfurization rate showed the important role of the products of partial destruction of heteropolyacid anions in the catalysis of the process. [ABSTRACT FROM AUTHOR]

The oxidation of ammonium sulfite obtained from ammonia-based flue gas desulfurization by hydrogen peroxide in aqueous solutions was studied using a stirred reactor. An experimental study of the kinetic parameters of the oxidation process was investigated in the pH of 4.2–5.2 at 25–50°C. $r = {k_3}\left[{{H^ + }} \right]\left[{HSO_3^ - } \right]\left[{{H_2}{O_2}} \right]$ r = k 3 H + HS O 3 − H 2 O 2 is valid at sulfite concentrations of 10−4 mol/L for the pH range 4.2–5.2. At 298K and pH of 5.0, third-order rate constant k3 was found to be (6.9 ± 0.21)×107 (mol/L)−2s−1. When the concentration of sulfite is 0.01 mol/L, the reaction first-order with respect to sulfite and hydrogen peroxide, and the second-order reaction rate constant at pH of 4.2–5.4 is $\lg {k_2} = - 1.0135pH + 7.4862$ lg k 2 = − 1.0135 pH + 7.4862. Activation energy of Ea = 32.26 kJ/moL. Kinetic data were compared with previous studies. A semi-empirical formula can express the effect of ionic strength on k3. The kinetic data of ammonium sulfite oxidation with hydrogen peroxide have potential applications in the wet ammonia desulfurization process. [ABSTRACT FROM AUTHOR]

Kerosene/hydrogen-peroxide (H2O2) green propellant system has relatively high operational ratio of oxidizer (O) to fuel (F) that complicates the injector design and its layout. In this research, a procedure of two-stage, like-doublet (O-F-F-O) impinging-jet injector design is presented, where mixing of H2O2 and kerosene occurs between O-O and F-F sprays. Investigations at O/F ratios between 3.75 and 6.25 are performed. The impinging distance, angle, and jet velocity of the two-stage impinging-jet module are the design parameters examined. The PLIF technique is used to observe the spatial droplet distribution of the individual spray. The predicted mixing behavior by overlapping the individual fuel and oxidizer sprays is compared to the actual mixing of the O-F-F-O spray to justify the spray/spray interactions. Detailed behaviors of the fuel and oxidizer sprays are revealed. The effects of O/F ratio and other design parameters on the injector flow dynamics and propellant mixing are examined systematically. With experimentally defined shape factors, an optimum design of the injector element can be determined for a given injector plate. The design of the injector plate for a 450 N thrust engine is demonstrated, and the design is justified by the hot-fire test of the engine. [ABSTRACT FROM AUTHOR]

Electrocatalytic production of hydrogen peroxide (H 2 O 2) by two electron water oxidation reaction (2e-WOR) is an environmental process with low cost and devoid of H 2 O 2 storage and transportation. ZnO is one of the important promising 2e-WOR catalysts with relatively high activity and selectivity of H 2 O 2. However, the active sites and the effects of oxygen defects of ZnO remain unknown, which hampers the further improvement in H 2 O 2 formation. To explore the active sites and develop Zn-based catalysts with high performance, Ni, Cu and Co ions are chosen to form M 0.1 Zn 0.9 O (M = Ni, Cu and Co) catalysts. Combining the experimental results with density functional theory (DFT) calculations, the active site of 2e-WOR on Zn-based catalysts is first discovered to be the 3-coordinated surface Zn without surface oxygen defects since oxygen defects result in a strong interaction of · OH with catalyst and then impede the 2e-WOR process. Catalysts with high activity and selectivity for 2e-WOR should have small nano-particle sizes without oxygen defects. Co 0.1 Zn 0.9 O is obtained with high activity (35.3 mmol min−1 · g cat −1) and selectivity (82%) of H 2 O 2 at 3.2 V vs RHE. This work provides valuable perspectives for designing and developing high-performing catalysts in 2e-WOR reaction. 3-coordinated surface Zn ions are the active sites of 2e-WOR; surface oxygen defects hamper the 2e-WOR process; Co 0.1 Zn 0.9 O with small particle sizes and no oxygen defects has high activity (35.3 mmol min−1·gcat−1) and selectivity (82%) of H 2 O 2. [Display omitted] • 3-coordinated surface Zn ions without surface O v are the active sites of 2e-WOR. • High-performing catalysts should have small sizes without oxygen defects. • Co 0.1 Zn 0.9 O has the highest activity and stability of H 2 O 2 compared to literatures. [ABSTRACT FROM AUTHOR]

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A sensitive near-infrared ratiometric fluorescence sensing platform was designed and structured. The platform consisted of carbon dots and a small organic molecule probe with pinacol phenylborate as the recognition group, and has been applied for ratio imaging of hydrogen peroxide in vivo. [ABSTRACT FROM AUTHOR]

Oral microecological balance is closely associated with the development of dental caries. Oxidative stress is one of the important factors regulating the composition and structure of the oral microbial community. Streptococcus mutans is linked to the occurrence and development of dental caries. The ability of S. mutans to withstand oxidative stress affects its survival competitiveness in biofilms. The oxidative stress regulatory mechanisms of S. mutans include synthesis of reductase, regulation of metal ions uptake, regulator PerR, transcription regulator Spx, extracellular uptake of glutathione, and other related signal transduction systems. Here, we provide an overview of how S. mutans adapts to oxidative stress and its influence on oral microecology, which may offer novel options to investigate the cariogenic mechanisms of S. mutans in the oral microenvironment, and new targets for the ecological prevention and treatment of dental caries. [ABSTRACT FROM AUTHOR]

Summary: In this research, the effects of washing treatments (potassium carbonate (PC), potassium hydroxide (PH), peracetic acid (PA), alkaline hydrogen peroxide (AHP)), ultrasound (US) and high‐intensity pulsed light (HIPL) technologies on the removal of ochratoxin A (OTA) residues in raisins were investigated. PC at 5 min (66.60%), PH at 10 min (65.25%), alkaline hydrogen peroxide at 5 min (63.30%) and HIPL at 12 J cm−2 (62.50%) were found to be the most successful applications in OTA degradation, respectively. Although the OTA degradation rate was high after chemical washing for 10 min, the raisins had a chemical odour. The results show that HIPL effectively reduces OTA levels in raisins without causing any quality loss. [ABSTRACT FROM AUTHOR]

Key message: MT mitigates chilling damage by enhancing antioxidant system and photosystem activities, and cold-responsive genes expression in cucumbers. H2O2 may act as a downstream signaling molecule in the MT-induced chilling tolerance. Melatonin (MT) and hydrogen peroxide (H2O2) are important endogenous signaling molecules that play multifaceted roles in plant responses to abiotic stress. However, the interactive mechanism by which MT and H2O2 regulate chilling tolerance remains unclear. Here we found that MT exhibited a positive regulatory effect on the chilling tolerance of cucumbers, with an optimum concentration of 100 µM. MT markedly enhanced RBOH1 mRNA expression, activity and endogenous H2O2 accumulation in cucumber seedlings. However, 1.0 mM H2O2 had no significant effect on mRNA levels of TDC and ASMT, the key genes for MT synthesis, and endogenous MT content. Both MT and H2O2 significantly decreased malondialdehyde (MDA), electrolyte leakage (EL) and chilling injury index (CI) by activating the antioxidant system, thereby alleviating chilling damage in cucumber seedlings. MT and H2O2 improved photosynthetic carbon assimilation, which was primarily attributed to an increase in activity, mRNA expression, and protein levels of RuBPCase and RCA. Meanwhile, MT and H2O2 induced the photoprotection for both PSII and PSI by enhancing the QA’s electron transport capacity and elevating protein levels of the photosystems. Moreover, MT and H2O2 significantly upregulated the expression of cold response genes. MT-induced chilling tolerance was attenuated by N′, N′-dimethylthiourea (DMTU), a H2O2 specific scavenger. Whereas, the MT synthesis inhibitor (p-chlorophenylalanine, p-CPA) did not influence H2O2-induced chilling tolerance. The positive regulation of MT on the antioxidant system, photosynthesis and cold response gene levels were significantly attenuated in RBOH1-RNAi plants compared with WT plants. These findings suggest that H2O2 may functions as a downstream signaling molecule in MT-induced chilling tolerance in cucumber plants. [ABSTRACT FROM AUTHOR]

Hydrogen peroxide (H2O2) has an important role in living organisms, and its detection is of great importance in medical, chemical, and food safety applications. This review provides a comparison of different types of Surface-enhanced Raman scattering (SERS) sensors for H2O2 and related substances with respect to their detection limits, which are of interest due to high sensitivity compared to conventional sensors. According to the latest research report, this review focuses on the sensing mechanism of different sensors and summarizes the linear range, detection limits, and cellular applications of new SERS sensors, and discusses the limitations in vivo and future prospects of SERS technology for the detection of H2O2. [ABSTRACT FROM AUTHOR]

This paper presents a comprehensive review of the physical and chemical properties of hydrogen peroxide as well as some regularities of its decomposition in the liquid phase. Hydrogen peroxide has been known for many decades and currently is one of the most important products of the chemical industry. Until recently, its use in the liquid state in rocket engines in space and defense has been limited due to storage and safety concerns. The latest research results made it possible to obtain hydrogen peroxide with higher purity and concentration as well as improved properties, safe and convenient in storage. As a result, hydrogen peroxide is widely considered for use in a wide range of rocket propulsion systems both as a bipropellant oxidizer and a monopropellant. As the size of the satellites being designed decreases, it is more and more difficult to select appropriate propulsion systems (PSs) ensuring required controllability and maneuverability. Currently, the smallest satellites (5–50 kg) usually use compressed gas. It is proposed to use hydrogen peroxide to improve efficiency, while reducing the cost compared to hydrazine PSs. As a monopropellant, hydrogen peroxide is characterized by high density (> 1,300 kg/m3) and specific impulse in vacuum of approx. 150 s (approx. 1,500 m/s). Its use in combination with hydrocarbons, pentaborane, and beryllium hydride is quite promising. The hydrogen peroxide/kerosene combination has particular advantages that make it convenient to use in rockets, especially when thrust control in a wide range is required. Its exceptional advantages are as follows: among various liquid fuel combinations, the hydrogen peroxide/kerosene combination is characterized by one of the highest fuel densities (approx. 1,270 kg/m3); besides, hydrogen peroxide tanks can be made of aluminum alloys, which significantly reduces their weight. Hydrogen peroxide is quite easy to handle since, unlike other oxidizers, it does not emit toxic vapors when stored and does not release toxic substances after combustion. The maximum permissible concentration of hydrogen peroxide vapors in the air of the working area is 0.3 mg/m3. Hazard class—2 according to GOST 12.1.007. From an environmental perspective, this fuel combination is comparable to the liquid oxygen/liquid hydrogen fuel. The need to install control engines for small satellites (e.g. Cubesat) is currently becoming a pressing issue. The use of neutral gases as a working fluid for control systems in such cases cannot compete with the use of, for example, hydrogen peroxide. At the same time, the creation of electric engines for small satellites is limited by the low available electrical power. [ABSTRACT FROM AUTHOR]

The study examined the protective effects of an aqueous extract of Salvia officinalis (Sage) in mice exposed to copper sulfate (CuSO4). Ten days of daily administration of 6 mg/kg CuSO4 were found to induce oxidative stress and neurotoxicity in the liver, brain, and kidney of mice. In fact, the activities of acetylcholinesterase (AChE), hydrogen peroxide (H2O2), and superoxide dismutase (SOD) decreased in the organs of mice. Furthermore, it was shown that CuSO4 caused a drop in cholesterol and triglyceride levels. Additionally, there was a general decrease in organ growth and body weight. Improvements in the antioxidant defense of the kidney and brain were observed to be promoted by the first concentration of 0.425 g/L (E1) of S. officinalis. In contrast, the second concentration of 1.275 g/L (E2) showed a greater improvement in SOD and AChE activities in liver. Sage extract (0.425 g/L) was able to raise the levels of AST, ALAT, and LDH in plasma. Additionally, it was noted that this concentration (E1) was beneficial for the growth of the three investigated organs as well as for preventing weight loss. [ABSTRACT FROM AUTHOR]

Summary: Chloroplast Unusual Positioning 1 (CHUP1) plays an important role in the chloroplast avoidance and accumulation responses in mesophyll cells. In epidermal cells, prior research showed silencing CHUP1‐induced chloroplast stromules and amplified effector‐triggered immunity (ETI); however, the underlying mechanisms remain largely unknown.CHUP1 has a dual function in anchoring chloroplasts and recruiting chloroplast‐associated actin (cp‐actin) filaments for blue light‐induced movement. To determine which function is critical for ETI, we developed an approach to quantify chloroplast anchoring and movement in epidermal cells. Our data show that silencing NbCHUP1 in Nicotiana benthamiana plants increased epidermal chloroplast de‐anchoring and basal movement but did not fully disrupt blue light‐induced chloroplast movement.Silencing NbCHUP1 auto‐activated epidermal chloroplast defense (ECD) responses including stromule formation, perinuclear chloroplast clustering, the epidermal chloroplast response (ECR), and the chloroplast reactive oxygen species (ROS), hydrogen peroxide (H2O2). These findings show chloroplast anchoring restricts a multifaceted ECD response.Our results also show that the accumulated chloroplastic H2O2 in NbCHUP1‐silenced plants was not required for the increased basal epidermal chloroplast movement but was essential for increased stromules and enhanced ETI. This finding indicates that chloroplast de‐anchoring and H2O2 play separate but essential roles during ETI. [ABSTRACT FROM AUTHOR]

In this study, we present a novel green synthesis method for magnesium oxide/magnesium peroxide nanocomposite using citric acid, enhancing both photocatalytic degradation and antioxidant activity. The physical properties and light absorption of the nanostructure were examined using X-ray diffraction, Fourier-transform infrared spectroscopy, scanning electron microscopy, and ultraviolet–visible spectroscopy techniques. A cubic phase was identified, with a nano-size of 25 nm, and a bandgap energy of 2.45 eV was determined. In the photocatalytic degradation tests, the nanostructure achieved an 85% removal rate of Brilliant Cresyl Blue dye after 120 min, with a pseudo-first-order rate constant of 0.014 min⁻¹. Computational simulations revealed a high adsorption energy of -131.552 eV for Brilliant Cresyl Blue on the magnesium oxide/magnesium peroxide nanocomposite, indicating strong binding affinity and supporting the experimental degradation efficiency. Antioxidant assays revealed a half-maximal inhibitory concentration value of 45.81 µg/mL, showcasing substantial free radical scavenging capabilities comparable to established antioxidants. The antibacterial properties of magnesium oxide/magnesium peroxide nanocomposite were assessed against Staphylococcus aureus through the agar well diffusion method. The results demonstrated significant antibacterial efficacy, with inhibition zones ranging from 7.9 ± 0.4 mm to 14.9 ± 1.5 mm, indicating a dose-dependent antibacterial effect. This research advances green synthesis methods for multifunctional nanomaterials, offering promising solutions for environmental remediation and highlighting the potential of magnesium oxide/magnesium peroxide nanocomposite in wastewater treatment, antioxidant applications, and as a potent antibacterial agent. [ABSTRACT FROM AUTHOR]

Pyridinic N functionalized DEB-N 2 displays strong O 2 adsorption ability and delivers a substantial H 2 O 2 generation with an initial rate of 3492 μmol g-1h−1 in pure water. [Display omitted] Artificial photosynthesis of hydrogen peroxide (H 2 O 2) is a hopeful alternative to the industrial anthraquinone process. However, rational fabrication of the photocatalysts for the production of H 2 O 2 without any sacrificial agents is still a formidable challenge. Herein, two kinds of linear conjugated polymers (LCPs) including pyridinic N functionalized polymer (DEB-N 2) and pyridinic N non-contained polymer (DEB-N 0) were successfully synthesized. DEB-N 2 displays enhanced light capturing ability and good dispersion in water, leading to a substantial initial H 2 O 2 generation rate of 3492μmol g-1h−1 as well as remarkable photocatalytic stability in pure water. Furthermore, the temperature programmed desorption (TPD) and density functional theory (DFT) analysis reveal that highly electronegative pyridine-N atoms in DEB-N 2 boost the adsorption affinity of oxygen molecules, which facilitates the occurrence of the oxygen reduction reaction, therefore enhancing the performance of photocatalytic H 2 O 2 production. This study unveils that the presence of pyridinic N in DEB-N 2 has a significant impact on photocatalytic H 2 O 2 production, suggesting the precise manipulation of the chemical structure of polymer photocatalysts is essential to achieve efficient solar-to-chemical energy conversion. [ABSTRACT FROM AUTHOR]

Among the most accepted hypotheses that can explain the causes of aging, we found the theory of free radicals in Lactobacillus gasseri strains. We did screen the antioxidative properties of Lactobacillus gasseri strains isolated from fermented milk. The results showed the most resistant strains against hydrogen peroxide with excellent superoxide anion radicals scavenging capacity. The results were also supported by DPPH free radical scavenging ability. We also found the greatest ferrous chelation capacity (reaching 88%). The tested strains demonstrated anti-lipid peroxidation levels ranging between 30 and 66%. The results suggest that L.gasseri could be used as an effective antioxidant to fight against diseases related to oxidative stress. [ABSTRACT FROM AUTHOR]

Copper, an essential metal for the energy transition, is primarily obtained from chalcopyrite through hydrometallurgical and pyrometallurgical methods. The risks and harmful impacts of these processes pose significant concerns for environmental and human safety, highlighting the need for more efficient and eco-friendly hydrometallurgical methods. This review article emphasizes current processes such as oxidative leaching, bioleaching, and pressure leaching that have demonstrated efficiency in overcoming the complicated chalcopyrite network. Oxidative leaching operates under benign conditions within the leaching media; nevertheless, the introduction of oxidizing agents provides benefits and advantages. Bioleaching, a non-aggressive method, has shown a gradual increase in copper extraction efficiency and has been explored using both primary and secondary sources. Pressure leaching, known for its effectiveness and selectivity in copper extraction, is becoming commercially more viable with increased research investments. This research also provides important data for advancing future research in the field. [ABSTRACT FROM AUTHOR]

Agricultural biomass is a well‐known renewable resource with a strong possibility of recycling. The current work focuses on extracting, preparing and colouring Napier grass fibre (NGF) with a colourant extracted from Rubia tinctorum (RT) (which is generally known as madder). NGF that had been water‐retted was alkaline scoured and bleached using hydrogen peroxide to increase the material's whiteness index and water absorption capacity without degrading its breaking strength. After being mordanted with tannic acid, the bleached NGF was coloured with an aqueous extract of the colourant extracted from RT. The Box–Behnken response surface methodology design model was employed to optimise the dyeing concentration, temperature and time. The dyed fibre showed good colour strength (K/S) and adequate wash, rub and light fastness. Adopting the findings from the current study would increase the efficient utilisation of biomass for use in textiles, which is unnecessarily wasted. [ABSTRACT FROM AUTHOR]

Salt-sensitive crop varieties suffer from oxidative stress as a consequence of osmotic and ionic stresses in plants under salinity stress. This study is aimed at identifying the effects of riboflavin (RIB) application on uplifting rice growth under salinized soil condition. Two-week-old seedlings of IR29 (a salt-sensitive variety) were supplemented with 0.5 μM of RIB, and 50 mM of NaCl was supplied for 2 weeks, inducing salinized soil conditions. The results indicated that RIB pretreatment (RP) seedlings possessed higher plant biomass, and lower electrolyte leakage ration (ELR), hydrogen peroxide (H2O2) and malondialdehyde (MDA) concentrations, higher chlorophyll, magnesium (Mg), and iron (Fe) concentrations in the leaf blades, a higher proline concentration, and a lower Na+ concentration in the leaf blades. To further understand the mechanisms behind the difference in plant growth between the RP and non-RP seedlings, molecular analysis revealed that RP seedlings upregulated OsNHX1 and OsHKT1;5 expressions were observed in the roots of RP seedlings, regulating Na+ uptake through the transpiration stream and reducing Na+ concentration in the leaf blades. Collectively, these results suggest that RP is a potent method for improving plant growth under salinized soil conditions. [ABSTRACT FROM AUTHOR]

One of the primary causes restricting wheat output is drought, which is turning into an increasingly serious issue in many of the world's wheat-growing countries. Through the investigation of biochemical parameters and gene expression analysis, the current study examined the impact of foliar application of green synthesized cerium nanoparticles (Ce NPs) in mitigating drought stress on wheat development. For the experimental investigation, two irrigation regimes (100% SMC and 50% SMC) and four distinct Ce NP concentrations (25 ppm, 50 ppm, 75 ppm, and 100 ppm) were employed. We found that applying Ce NPs topically increased wheat plants' overall capacity to withstand drought. Among the different concentrations used, the foliar application with 50-ppm Ce NPs substantially increased the antioxidant enzyme activity, proline content, relative water content, and all photosynthetic matrices under drought stress conditions, in comparison with the control. Ce NPs treatment also lowered the hydrogen peroxide (50.53%) and malondialdehyde amounts (22.79%) under drought stress. To substantiate the impact of Ce NPs at the molecular level, we also examined the gene expression of five stress-related genes (MYB33, MYB3R, DREB2, ABC1, and SnRK2.4) and observed their upregulated expression after Ce NPs treatment under drought stress conditions. These results demonstrate the use of Ce NPs as a new strategy to mitigate the detrimental effects of drought stress in wheat. Illustrating the role of Ce NPs in mitigating drought stress in plants through biochemical and molecular regulation (created in BioRenders.com) [ABSTRACT FROM AUTHOR]

Arsenic (As) significantly affects production and quality of rice (Oryza sativa L), the global staple food. Therefore, there is a need for As tolerant rice and so, present work is designed to identify the highest As tolerant and sensitive rice cultivars of North-East (NE), India, and the key mechanisms for the sensitivity and tolerance. Hydroponically grown twenty rice cultivars of NE were analyzed for the changes in growth, As content and Arsenic tolerant index % (ATI%) after 7th day of As treatments (0, 100 and 300 µM), where Phougak rice was found to be the highest tolerant having highest ATI% while cultivar with IC no. 200507 with least ATI%, the highly sensitive to As. The sensitivity and tolerance of the rice against As were further analyzed through the evaluation of morphological and histochemical changes, relative water content, chlorophyll content, hydrogen peroxide (H2O2) and lipid peroxidation level, and antioxidant metabolites and enzymes activities. Arsenic significantly increased H2O2 level, resulted into lipid peroxidation and cell death in sensitive rice, moreover, scanning electron microscopy also revealed damaging effect of As in the plant. However, no damaging effect was observed in the tolerant rice, but considerable increase of ascorbate and glutathione content and activity of antioxidant enzymes were recorded. Hence, high accumulation of As induced ROS in sensitive rice, while constant detoxification of the ROS in tolerant rice by efficient antioxidant defence system could be the reasons for the sensitivity of 200507 and tolerance of Phougak rice to As stress. [ABSTRACT FROM AUTHOR]

This study aimed to explore the protective effects of Euonymus alatus (EA) leaves and its compounds on hydrogen peroxide (H2O2)-induced neuronal cell death. EA effectively reversed the H2O2-induced decrease in HT22 cell viability. Anti-apoptotic marker poly(ADP-ribose) polymerase significantly increased with EA treatment, whereas BAX/BCL2 and cleaved caspase-3/procaspase-3 ratios, which represent apoptotic markers, were dose-dependently decreased by EA treatment. Additionally, EA effectively decreased β-secretase production, acetylcholine esterase activity, and Tau phosphorylation, pathological features observed in Alzheimer's disease. Furthermore, EA significantly increased the protein levels of NRF2 and HO-1, as well as the gene expression of antioxidant enzymes, including catalase, superoxide dismutase 1, and glutathione peroxidase. LC–MS/MS and HPLC analyses revealed the presence of chlorogenic acid and leucosides in EA. Both chlorogenic acid and leucosides showed protective effects against H2O2-induced neuronal cell death. This study highlights the potential of EA and its compounds as functional edible agents for neuroprotection against oxidative stress. [ABSTRACT FROM AUTHOR]

In this study, we provide electrochemical techniques for synthesizing thermally reduced graphene nanomaterial that have high potential, low defects, cost-effectiveness, and ecological sustainability. The electrochemical exfoliation is carried out by employing a 195 W DC (voltage = 60 V and current = 3.25 A) power source at a maximum electrolyte temperature of about 92.5∘C within the aqueous suspension of 2 M of sulfuric acid (H2 SO 4). Thereafter, the synthesized nanomaterial was treated in the weak piranha [combination of sulfuric acid and hydrogen peroxide (H2 O 2) ] solution using an electrochemical technique inside the water bath sonicator at 80∘C. X-ray diffraction (XRD) analysis shows the peak of diffraction to the (002) plane of the reduced graphene oxide (RGO) samples emerges at around 2 θ = 2 6. 4 0 ∘ and 26.56∘ with an interplanar distance of 3.40 Å and 3.54 Å. According to the XRD data, after the high-temperature thermal reduction phase, the structure of the crystals and interplanar separation were recovered. The size of the crystallite of RGO produced under H2SO4 conditions was discovered to be greater than the crystallite size of graphene oxide produced under piranha solution conditions. The Raman analysis results show that the degree of disorder of the graphene synthesized within the H2O2 was higher than in comparison to the graphene synthesized in H2SO4. Field emission scanning electron microscopy (FE-SEM) results show that graphene synthesized in the presence of H2O2 has a thin and porous microstructure in comparison to H2SO4 with no significant effect on the presence of the availability of the C/O ratio. The atomic force microscopy (AFM) analysis indicates that the surface roughness of the graphene synthesized in the H2O2 was higher than that of the H2SO4. The Fourier transform infrared spectroscopy (FT-IR spectroscopy) analytical results show that the majority of the functional groups have been eliminated within the samples. [ABSTRACT FROM AUTHOR]

SUMMARY Ascorbic acid (AsA) serves as a key antioxidant involved in the various physiological processes and against diverse stresses in plants. Due to the insufficiency of AsA de novo biosynthesis, the AsA regeneration is essential to supplement low AsA synthesis rates. Redox reactions play a crucial role in response to biotic stress in plants; however, how AsA regeneration participates in hydrogen peroxide (H2O2) homeostasis and plant defense remains largely unknown. Here, we identified a Golgi vesicle‐membrane‐localized cytochrome B561 (CytB561) encoding gene, GhB561‐11, involved in AsA regeneration and plant resistance to Verticillium dahliae in cotton. GhB561‐11 was significantly downregulated upon V. dahliae attack. Knocking down GhB561‐11 greatly enhanced cotton resistance to V. dahliae. We found that suppressing GhB561‐11 inhibited the AsA regeneration, elevated the basal level of H2O2, and enhanced the plant defense against V. dahliae. Further investigation revealed that GhB561‐11 interacted with the lipid droplet‐associated protein GhLDAP3 to collectively regulate the AsA regeneration. Simultaneously silencing GhB561‐11 and GhLDAP3 significantly elevated the H2O2 contents and dramatically improved the Verticillium wilt resistance in cotton. The study broadens our insights into the functional roles of CytB561 in regulating AsA regeneration and H2O2 homeostasis. It also provides a strategy by downregulating GhB561‐11 to enhance Verticillium wilt resistance in cotton breeding programs. [ABSTRACT FROM AUTHOR]

Carbon nitride is a promising photocatalyst for hydrogen peroxide (H2O2) production under visible light irradiation. However, current carbon nitride-based photocatalysts show limited H2O2 production owing to high impedance and poor charge transfer ability. In this work, we present a series of CuO decorated graphitic phase carbon nitride (g-C3N4) composites, exhibiting suitable bandgaps for the photocatalytic production of H2O2. The experimental results showed that CuO/g-C3N4 composites exhibited excellent photocatalytic H2O2 production performance and good photocatalytic cycle stability. Significantly, the optimized 30%-CuO/g-C3N4 composite exhibits a high H2O2 yield of 2722.47 μmol L−1 with the addition of CH3OH under visible light. Furthermore, the photocatalytic mechanism is well studied by density functional theory calculations. This work demonstrates that CuO/g-C3N4 composites hold great promise for photocatalytic H2O2 production application. [ABSTRACT FROM AUTHOR]

Hydrogen peroxide (H2O2) is gaining prominence as a versatile oxidizing agent and sustainable energy carrier, prompting the need for efficient and eco‐friendly production methods. Traditional approaches face challenges such as high energy consumption and environmental impact, driving interest towards alternative methods like photocatalysis and electrocatalysis. Graphitic carbon nitride (g‐C3N4) has emerged as a promising photocatalyst due to its inherent band structure that facilitates solar energy utilization. However, bare g‐C3N4 encounters limitations like rapid charge recombination and limited light absorption. Recent advancements have focused on enhancing g‐C3N4 photocatalysts through carbon vacancy (Cv) engineering, which effectively modifies electronic and surface properties to improve photocatalytic performance. This mini‐review explores the fundamental principles and recent advancements in Cv‐engineered g‐C3N4 photocatalysts for H2O2 production. It discusses the critical roles of carbon vacancies in enhancing the photocatalytic performance of g‐C3N4, along with methods for creating carbon vacancies in g‐C3N4 and their impact on photocatalytic H2O2 production. The review also addresses challenges related to scalable synthesis and practical deployment of Cv‐g‐C3N4 materials, providing insights into future research directions for sustainable photocatalytic technologies. [ABSTRACT FROM AUTHOR]

One of the reactive forms of oxygen is hydrogen peroxide (H2O2), which has been investigated as a key component of growth processes and stress responses. Different methods for the determination of H2O2 production by animal and bacterial cells exist; however, its detection in algal cell cultures is more complicated due to the presence of photosynthetic pigments in the cells and the complex structure of cell walls. Considering these issues, a reliable, quick, and simple method for H2O2 detection is needed in phycological research. The aim of this methodological study was to optimize an Amplex UltraRed method for the fluorometric detection of H2O2 produced by microalgae cells, using a wild‐type strain of Chlamydomonas reinhardtii as a model. The results showed that (i) potassium phosphate is the most suitable reaction buffer for this method, (ii) a 560 nm wavelength variant is the most appropriate as the excitation wavelength for fluorescence spectra measurement, (iii) a 50:50 ratio for the reaction mixture to sample was the most suitable, (iv) the fluorescence signal was significantly influenced by the density of the microalgae biomass, and (v) sample fortification with H2O2 allowed for an increase of the method's reliability and repeatability. The proposed protocol of the Amplex UltraRed method for the fluorometric detection of H2O2 produced by microalgae cells can yield a sensitive and accurate determination of the content of the test compound, minimizing measurement errors, eliminating chlorophyll autofluorescence problem, and compensating for the matrix effect. This method can be applied to the study of other microalgae species. [ABSTRACT FROM AUTHOR]

Covalent organic frameworks (COFs) have been demonstrated as promising photocatalysts for hydrogen peroxide (H2O2) production. However, the construction of COFs with new active sites, high photoactivity, and wide‐range light absorption for efficient H2O2 production remains challenging. Herein, we present the synthesis of a novel azobenzene‐bridged 2D COF (COF‐TPT‐Azo) with excellent performance on photocatalytic H2O2 production under alkaline conditions. Notably, although COF‐TPT‐Azo differs by only one atom (−N=N− vs. −C=N−) from its corresponding imine‐linked counterpart (COF‐TPT‐TPA), COF‐TPT‐Azo exhibits a significantly narrower band gap, enhanced charge transport, and prompted photoactivity. Remarkably, when employed as a metal‐free photocatalyst, COF‐TPT‐Azo achieves a high photocatalytic H2O2 production rate up to 1498 μmol g−1 h−1 at pH = 11, which is 7.9 times higher than that of COF‐TPT‐TPA. Further density functional theory (DFT) calculations reveal that the −N=N− linkages are the active sites for photocatalysis. This work provides new prospects for developing high‐performance COF‐based photocatalysts. [ABSTRACT FROM AUTHOR]

Hydrogen peroxide (H2O2) is gaining prominence as a versatile oxidizing agent and sustainable energy carrier, prompting the need for efficient and eco‐friendly production methods. Traditional approaches face challenges such as high energy consumption and environmental impact, driving interest towards alternative methods like photocatalysis and electrocatalysis. Graphitic carbon nitride (g‐C3N4) has emerged as a promising photocatalyst due to its inherent band structure that facilitates solar energy utilization. However, bare g‐C3N4 encounters limitations like rapid charge recombination and limited light absorption. Recent advancements have focused on enhancing g‐C3N4 photocatalysts through carbon vacancy (Cv) engineering, which effectively modifies electronic and surface properties to improve photocatalytic performance. This mini‐review explores the fundamental principles and recent advancements in Cv‐engineered g‐C3N4 photocatalysts for H2O2 production. It discusses the critical roles of carbon vacancies in enhancing the photocatalytic performance of g‐C3N4, along with methods for creating carbon vacancies in g‐C3N4 and their impact on photocatalytic H2O2 production. The review also addresses challenges related to scalable synthesis and practical deployment of Cv‐g‐C3N4 materials, providing insights into future research directions for sustainable photocatalytic technologies. [ABSTRACT FROM AUTHOR]

Background: Charcoal rot of soybean is caused by the hemibiotrophic fungus Macrophomina phaseolina, a global crop destroyer and an important pathogen in the midwestern USA. The quantitative nature of host resistance and the complexity of the soybean-M. phaseolina interaction at the molecular level have hampered resistance breeding. A previous study showed that L-ascorbic acid (LAA) pre-treatment before M. phaseolina inoculation reduced charcoal rot lesion length in excised soybean stems. This study aimed to elucidate the genetic underpinnings of M. phaseolina-induced senescence and the mitigating effects of ascorbic acid on this physiological process within the same pathosystem. Results: RNA was sequenced from M. phaseolina-resistant and -susceptible soybean genotypes following M. phaseolina inoculation, LAA, and hydrogen peroxide (H2O2)—an oxidative stress inducer—application followed by inoculation. More genes were down-regulated in the resistant and susceptible genotypes than up-regulated when the M. phaseolina-inoculated treatments were compared to mock-inoculated control treatments. Gene ontology (GO) term and KEGG pathways analysis detected M. phaseolina-induced up-regulation of receptor-like kinase genes. In contrast, many genes related to antioxidants, defense, and hormonal pathways were down-regulated in both genotypes. LAA pre-treatment induced genes related to photosynthesis and reactive oxygen species responses in both genotypes. H2O2 pre-treatment following inoculation up-regulated many stress-response genes, while hormone signal transduction and photosynthesis-related genes were down-regulated in both genotypes. Conclusions: Results revealed transcriptional variation and genes associated with M. phaseolina-induced senescence in soybean. Ascorbic acid induced many photosynthetic genes, suggesting a complex regulation of defense and immunity in the plant against the hemibiotroph. Soybean plants also exhibited enhanced stress responsiveness when treated with H2O2 followed by inoculation with M. phaseolina. This study will broaden more research avenues related to transcriptional regulation during the M. phaseolina-soybean interaction and the potential role of receptor-like kinases, oxidative stress-responsive genes, ethylene-mediated signaling and enhanced photosynthetic gene expression when mounting host resistance to this important soybean pathogen. [ABSTRACT FROM AUTHOR]

We measured diurnal variations in oxidative stress conditions of cyanobacteria utilizing field observations and laboratory experiments in order to evaluate photoinhibition effects. On clear summer days, transparent bottles filled with surface water were set up at several depths and were collected every three hours together with the measurement of the photosynthetically active radiation (PAR). In the laboratory experiment, two cyanobacterial species were exposed to gradually increasing and then decreasing light intensities. The samples were analyzed with the PAR-induced (H2O2), along with the total hydrogen peroxide concentrations (total H2O2), the catalase activities (CAT), OD730, protein (Protein), and chlorophyll a (Chl a) contents, and so on. Protein was significantly proportionate with OD730 and Chl a, and was used as an indicator of cell biomass. Increasing PAR, H2O2 concentration increased proportionately with the PAR intensity. Then, an oxidative stress indicator in a cell, H2O2/Protein is given by the PAR divided by cell volume, evaluated by Protein. CAT activity in a cell, far largest among antioxidant activities, solely followed total H2O2/Protein. The prediction model for H2O2/Protein was developed with the sufficient agreement with the experimental and field observation results. The model elucidated that the maximum H2O2/Protein in a day was larger with lower cell density even at the water surface, indicating that the higher photoinhibition was imposed at low density, in addition to the lower attenuation of PAR. These results indicate that H2O2/Protein is an effective biomarker to indicate the stress level of cyanobacteria; the observed levels of H2O2 to freshwater may prove useful in designing the criteria for cyanobacteria management. [ABSTRACT FROM AUTHOR]

Developing metal‐free carbon catalysts is critical to achieve the electrosynthesis of hydrogen peroxide (H2O2) via two‐electron oxygen reduction reaction (2e− ORR) using seawater as electrolyte. Herein, N‐rich doped carbon (NC) is synthesized by directly pyrolyzing guanine as both N and C sources, which can facilitate the formation of ultrahigh‐N dopant (up to 33.89 at.%), and their ratios. The NC obtained at 700 °C with hydrogenated pyridine‐N and pyrrole‐N (3:2) dopants exhibits a superior selectivity of H2O2 (up to 96%), high mass activity of 545.5 A g−1 at 0.2 V versus RHE and stable production of H2O2 with 16.8 molgcat−1h−1${\rm{mol}}\;{\rm{g}}_{{\rm{cat}}}^{ - 1}{{{\rm{h}}}^{ - 1}}$ in 0.5 M NaCl. In situ Fourier transform infrared spectrum analysis proves that hydrogenated pyridine‐N and pyrrole‐N dopants play a critical role in constructing metal‐free active sites for the synthesis of H2O2. Meanwhile, theoretical calculations further reveal that compared to non‐hydrogenated N dopants, hydrogenated pyridine and pyrrole N can tune the projected density of states of 2pz orbitals of their adjacent carbon atoms approaching Fermi Level, enhancing *OOH to H2O2 through 2e− ORR rather than H2O via 4e− ORR. This work provides new insights for developing metal‐free catalysts for efficient electrosynthesis of H2O2 using seawater resources as promising electrolytes. [ABSTRACT FROM AUTHOR]

Water decreases the brightness of the peroxyoxalate chemiluminescence partially due to the hydrolysis of the oxalate reagent. Here, we show that encapsulation of an oxalate ester and the fluorescent activator in microspheres of cellulose esters increases the emission intensity 30 times compared to the same reaction in water without encapsulation, whereas the emission intensity decay rate constants are considerably lower. Emission intensities, rate constants and chemiluminescence quantum yields increase with increasing hydrogen peroxide concentrations. These results expand the potential of application of chemiluminescence, contributing for the development of ultrasensitive analytical methods. [ABSTRACT FROM AUTHOR]

ABSTRACT This study explores plasma‐activated water (PAW) generation in a pin‐to‐water (P2W) setup, examining how operating current affects N O X ${\rm{N}}{{\rm{O}}}_{{\rm{X}}}$ gas production and its interaction with neutral pH range water. High‐current mode (HCM‐32.3 mA) significantly increases hydrogen peroxide (H 2 O 2 ) ${{\rm{H}}}_{2}{{\rm{O}}}_{2})$ by 2x and nitrite (N O 2 − ${\rm{N}}{{\rm{O}}}_{2}^{-}$) by 1.5x over low‐current mode (LCM‐19.5 mA), with H 2 O 2 ${{\rm{H}}}_{2}{{\rm{O}}}_{2}$ and N O 2 − ${\rm{N}}{{\rm{O}}}_{2}^{-}$ concentrations reaching 161 mg/L and 1070 mg/L, respectively. These findings align with increased N O X ${\rm{N}}{{\rm{O}}}_{{\rm{X}}}$ gas production. The study underscores the air–water interface's role in PAW chemistry, with ICCD emission and chemical‐workbench (CWB) simulations providing further reaction insights. Overall, it highlights operating current as a critical factor in PAW chemistry and the role of N O X ${\rm{N}}{{\rm{O}}}_{{\rm{X}}}$ in reactive nitrogen species formation. [ABSTRACT FROM AUTHOR]

As one of the important components of active oxygen species, H2O2 (hydrogen peroxide) plays an important role in life activities. Many studies have shown that a high concentration of H2O2 can cause cell necrosis, resulting in oxidative stress and oxidative damage in the body, and then induce various diseases. The application of organic small molecule fluorescent probes in life sciences has attracted the attention of many researchers because of their advantages of being easy to obtain, high spatial and temporal resolution, little damage to biological samples and simple operation. In this study, a new hydrogen peroxide near infrared fluorescence probe JH was constructed using oxanthrene analogues as a molecular framework. The fluorescence emission wavelength of the probe is located in the near infrared region and has a large Stokes shift, which makes the probe less damaging to biological samples and gives lower background interference, which is conducive to improving the detection resolution. The probe can complete the response to H2O2 within 95 min with a low detection limit (4.72 μM), and the color of the solution changes from dark blue to light blue after the response, so H2O2 can be recognized by the naked eye without any tools. In addition, probe JH has been successfully used for the detection of H2O2 in cells, which is expected to become a tool for early diagnosis of diseases. [ABSTRACT FROM AUTHOR]

As a new type of artificial enzyme, a nanozyme is an ideal substitute for natural enzymes and has been successfully applied in many fields. However, in the application of biomolecular detection, most nanozymes have the disadvantages of long reaction times or high detection limits, prompting researchers to search for new efficient nanozymes. In this work, the enzyme-like activities of three polyoxometalate-based iron-organic complexes ([Fe(bpp)2](Mo6O19), [Fe(bpp)2]2(Mo8O26)·2CH3OH, and [Fe(bpp)2]4H[Na(Mo8O26)]3), namely, FeMo6, Fe2Mo8, and Fe4Mo8Na, were analyzed. All three polyoxometalate-based iron-organic complexes were found to be capable of catalyzing hydrogen peroxide (H2O2) to oxidize 3,3′,5,5′-tetramethylbenzidine and o-phenylenediamine, resulting in visible color changes, further exhibiting peroxidase-like activity. Results showed that Fe4Mo8Na had more active sites due to its long chain structure, endowing more prominent peroxidase-like activity compared with Fe2Mo8 and FeMo6. A colorimetric sensing platform for H2O2 and ascorbic acid detection based on Fe4Mo8Na was established. The linear response range for H2O2 detection was 0.5–100 μM, and the detection limit was 0.143 μM. The linear response for ascorbic acid detection ranges from 0 to 750 μM with a detection limit of 1.07 μM. This study provides a new perspective for developing new nanozymes and expanding the sensing and detection application of nanozymes. [ABSTRACT FROM AUTHOR]

Nanozymes are nanomaterials with mimetic enzyme properties and the related research has attracted much attention. It is of great value to develop methods to construct nanozymes and to study their application in bioanalysis. Herein, the metal–ligand cross-linking strategy was developed to fabricate superstructure nanozymes. This strategy takes advantage of being easy to operate, adjustable, cheap, and universal. The fabricated superstructure nanozymes possess efficient peroxidase-like catalytic activity. The enzyme reaction kinetic tests demonstrated that for TMB and H2O2, the Km is 0.229 and 1.308 mM, respectively. Furthermore, these superstructure nanozymes are applied to highly efficient and sensitive detection of glucose. The linear range for detecting glucose is 20–2000 μM, and the limit of detection is 17.5 μM. Furthermore, mechanistic research illustrated that this integrated system oxidizes glucose to produce hydrogen peroxide and further catalyzes the production of ·OH and O2·–, which results in a chromogenic reaction of oxidized TMB for the detection of glucose. This work could not only contribute to the development of efficient nanozymes but also inspire research in the highly sensitive detection of other biomarkers. [ABSTRACT FROM AUTHOR]

Nanozyme technology has gained significant regard and been successfully implemented in various applications including chemical sensing, bio-medicine, and environmental monitoring. Fe-CDs were synthesized and characterized well in this study. As compared to HRP (3.7 mM), the Fe-CDs exhibited a higher affinity towards H2O2 (0.2 mM) using the steady-state kinetic assay and stronger catalytic capability by changing the color of TMB to the blue color of the oxidized state, oxTMB. Additionally, an efficient peroxidase mimic, Fe-CDs/GOx, based on the hybrid cascade system to produce in situ H2O2 for the visual detection of glucose (color change: colorless to blue, and then to green), has been developed in detail, with limits of detection (LODs) for H2O2 and glucose of 0.33 μM and 1.17 μM, respectively. The changes further demonstrate a linear relationship between absorbance and H2O2 concentration, ranging from 10 to 60 μM, and for glucose (1 to 60 μM). To assess the accuracy and detection capability of the Fe-CDs/GOx system, we evaluated a real human serum sample obtained from adult males in a local hospital. In conclusion, Fe-CDs serving as a peroxidase mimic have the potential for various applications in the fields of biomedicine and nanozymes. [ABSTRACT FROM AUTHOR]