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

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

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

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]

The impact of climate change on agricultural production is apparent due to declining irrigation water availability vis-à-vis rising drought stress, particularly affecting summer crops. Growing evidence suggests that zinc (Zn) supplementation may serve as a potential drought stress management strategy in agriculture. Field studies were conducted using soybean (Glycine max var. Saba) as a model crop to test whether foliar application of zinc oxide nanoparticles (ZnO-NPs) or conventional Zn fertilizer (ZnSO4) would mitigate drought-related water stress and improve soybean yield. Each fertilizer was foliar applied twice at a two-week interval during the flowering stage. Experiments were concurrently conducted under non-drought conditions (70% field capacity) for comparison. Results showed drought significantly reduced relative water content, chlorophyll-a, and chlorophyll-b in untreated control plants by 35.7%, 47.7%, and 41.4%, respectively, compared to non-drought conditions (p < 0.05). Under drought conditions, ZnO-NPs (200 mg Zn/L) led to 33.1% and 20.7% increase in chlorophyll-a and chlorophyll-b levels, respectively, compared to ZnSO4 at 400 mg Zn/L. Likewise, catalase, peroxidase and superoxide dismutase activities increased by 62.6%, 39.5% and 28.5%, respectively, with ZnO-NPs (200 mg Zn/L) under drought compared to non-drought conditions. Proline was significantly increased under drought but was remarkably suppressed (~ 54% lower) with ZnO-NPs (200 mg Zn/L) treatment. More importantly, the highest seed yield was observed with ZnO-NPs (200 mg Zn/L) treatment under drought (39% higher than untreated control) and non-drought (79.4% higher than control) conditions. Overall, the findings suggest that ZnO-NPs could promote seed yield in soybean under drought stress via increased antioxidant activities, increased relative water content, decreased stress-related proline content, and increased photosynthetic pigments. It is recommended that foliar application of 200 mg Zn/L as ZnO-NPs could serve as an effective drought stress management strategy to improve soybean yield. [ABSTRACT FROM AUTHOR]

The impact of climate change on agricultural production is apparent due to declining irrigation water availability vis-à-vis rising drought stress, particularly affecting summer crops. Growing evidence suggests that zinc (Zn) supplementation may serve as a potential drought stress management strategy in agriculture. Field studies were conducted using soybean (Glycine max var. Saba) as a model crop to test whether foliar application of zinc oxide nanoparticles (ZnO-NPs) or conventional Zn fertilizer (ZnSO4) would mitigate drought-related water stress and improve soybean yield. Each fertilizer was foliar applied twice at a two-week interval during the flowering stage. Experiments were concurrently conducted under non-drought conditions (70% field capacity) for comparison. Results showed drought significantly reduced relative water content, chlorophyll-a, and chlorophyll-b in untreated control plants by 35.7%, 47.7%, and 41.4%, respectively, compared to non-drought conditions (p < 0.05). Under drought conditions, ZnO-NPs (200 mg Zn/L) led to 33.1% and 20.7% increase in chlorophyll-a and chlorophyll-b levels, respectively, compared to ZnSO4 at 400 mg Zn/L. Likewise, catalase, peroxidase and superoxide dismutase activities increased by 62.6%, 39.5% and 28.5%, respectively, with ZnO-NPs (200 mg Zn/L) under drought compared to non-drought conditions. Proline was significantly increased under drought but was remarkably suppressed (~ 54% lower) with ZnO-NPs (200 mg Zn/L) treatment. More importantly, the highest seed yield was observed with ZnO-NPs (200 mg Zn/L) treatment under drought (39% higher than untreated control) and non-drought (79.4% higher than control) conditions. Overall, the findings suggest that ZnO-NPs could promote seed yield in soybean under drought stress via increased antioxidant activities, increased relative water content, decreased stress-related proline content, and increased photosynthetic pigments. It is recommended that foliar application of 200 mg Zn/L as ZnO-NPs could serve as an effective drought stress management strategy to improve soybean yield. [ABSTRACT FROM AUTHOR]

Hydrogen peroxide (H2O2) has practical applications in healthcare, food security, and environmental protection. The current study has been focused on creating H2O2 sensors using a bimetallic composition of polypyrrole/Cobalt-silver on indium tin oxide (ITO) through electrochemical fabrication. Composite hybrid materials comprising Co@Ag/PPy/ITO were successfully synthesized using chronoamperometry and pulsed electrodeposition techniques. The obtained electrode (Co@Ag/PPy/ITO) was studied using scanning electron microscopy (SEM), ultraviolet–visible, and cyclic voltammetry techniques. The energy-dispersive X-ray spectroscopy and SEM revealed that silver and cobalt nanoparticles were distributed on the PPy surface, forming fern-like structures. A detailed investigation of the electrochemical properties of the bimetallic composition was conducted using cyclic voltammetry (CV), chronoamperometry, and electrochemical impedance spectroscopy. The amperometric method and CV were used to carry out the electrochemical detection of H2O2. The non-enzymatic H2O2 sensor exhibited an enhanced amperometry response, showing a higher sensitivity of 3.664 mA mM−1 cm−2 within a linear range spanning 0.12–2.36 mM. Notably, the sensor achieved a low detection limit of 1.985 μM (S/N = 3). Additionally, the nanocomposite hybrids demonstrated superior stability, repeatability, and reproducibility, making this sensor suitable for long-term use. [ABSTRACT FROM AUTHOR]

Photocatalytic technology is considered to be a sustainable strategy to convert H2 O and O2 into H2 O2. However, constructing photocatalytically active and stable organic photocatalyst remain a challenge. In this study, a new class of porous aromatic framework photocatalysts (BF-PAFs) were designed and synthesized, in which 9,9′-bifluorenylidene (99′-BF) and different alkynes are alternately connected. The BF-PAFs were constructed and served as photocatalysts for H2 O2 synthesis. Experimental results show that the introduction of different alkynes can effectively regulate the optical band gap and energy band structure, which may further determine their photocatalytic performance. Upon visible light irradiation, PAF-370 exhibits high efficiency for photosynthesis of H2 O2 with a production rate of 730 μmol g–1 h–1 in the presence of sacrificial reagent from water and oxygen via oxygen reduction reaction (ORR) pathway. Furthermore, up to 61 μmol H2 O2 could be generated from this photocatalytic system after 14 hours. [ABSTRACT FROM AUTHOR]

Electrochemical synthesis of hydrogen peroxide (H2O2) via the two‐electron oxygen reduction reaction (2e−‐ORR) provides an alternative method to the energy‐intensive anthraquinone method. Metal macrocycles with precise coordination are widely used for 2e−‐ORR electrocatalysis, but they have to be commonly loaded on conductive substrates, thus exposing a large number of 2e−‐ORR‐inactive sites that result in poor H2O2 production rate and efficiency. Herein, guided by first‐principle predictions, a substrate‐free and two‐dimensional conductive metal–organic framework (Ni‐TCPP(Co)), composed of CoN4 sites in porphine(Co) centers and Ni2O8 nodes, is designed as a multi‐site catalyst for H2O2 electrosynthesis. The approperiate distance between the CoN4 and Ni2O8 sites in Ni‐TCPP(Co) weakens the electron transfer between them, thus ensuring their inherent activities and creating high‐density active sites. Meanwhile, the intrinsic electronic conductivity and porosity of Ni‐TCPP(Co) further facilitate rapid reaction kinetics. Therefore, outstanding 2e−‐ORR electrocatalytic performance has been achieved in both alkaline and neutral electrolytes (>90 %/85 % H2O2 selectivity within 0–0.8 V vs. RHE and >18.2/18.0 mol g−1 h−1 H2O2 yield under alkaline/neutral conditions), with confirmed feasibility for water purification and disinfection applications. This strategy thus provides a new avenue for designing catalysts with precise coordination and high‐density active sites, promoting high‐efficiency electrosynthesis of H2O2 and beyond. [ABSTRACT FROM AUTHOR]

Electrochemical synthesis of hydrogen peroxide (H2O2) via the two‐electron oxygen reduction reaction (2e−‐ORR) provides an alternative method to the energy‐intensive anthraquinone method. Metal macrocycles with precise coordination are widely used for 2e−‐ORR electrocatalysis, but they have to be commonly loaded on conductive substrates, thus exposing a large number of 2e−‐ORR‐inactive sites that result in poor H2O2 production rate and efficiency. Herein, guided by first‐principle predictions, a substrate‐free and two‐dimensional conductive metal–organic framework (Ni‐TCPP(Co)), composed of CoN4 sites in porphine(Co) centers and Ni2O8 nodes, is designed as a multi‐site catalyst for H2O2 electrosynthesis. The approperiate distance between the CoN4 and Ni2O8 sites in Ni‐TCPP(Co) weakens the electron transfer between them, thus ensuring their inherent activities and creating high‐density active sites. Meanwhile, the intrinsic electronic conductivity and porosity of Ni‐TCPP(Co) further facilitate rapid reaction kinetics. Therefore, outstanding 2e−‐ORR electrocatalytic performance has been achieved in both alkaline and neutral electrolytes (>90 %/85 % H2O2 selectivity within 0–0.8 V vs. RHE and >18.2/18.0 mol g−1 h−1 H2O2 yield under alkaline/neutral conditions), with confirmed feasibility for water purification and disinfection applications. This strategy thus provides a new avenue for designing catalysts with precise coordination and high‐density active sites, promoting high‐efficiency electrosynthesis of H2O2 and beyond. [ABSTRACT FROM AUTHOR]

Here, a novel paired electrolysis system is constructed, where fluorine-doped tin oxide glass serves as the anode for the water oxidation reaction to produce hydrogen peroxide (H2O2), and cobalt phthalocyanine (CoPc)/carbon nanotube (CNT) loaded carbon paper as the cathode for CO2 reduction to generate CO. This system demonstrates a high overall energy efficiency of 34%, where a faradaic efficiency exceeding 90% for CO2 reduction and 60% for water oxidation to H2O2 have been achieved, demonstrating significant energy savings of nearly 40% compared to the respective half-reaction systems. [ABSTRACT FROM AUTHOR]

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This work investigated the photochemical degradation of malachite green (MG), a cationic triphenylmethane dye used as a coloring agent, fungicide, and antiseptic. UV photolysis was ineffective in the removal of MG as only 12.35% degradation of MG (10 mg/L) was achieved after 60 min of irradiation. In contrast, 100.00% degradation of MG (10 mg/L) was observed after 60 min of irradiation in the presence of 10 mM H2O2 by UV/H2O2 at pH 6.0. Similarly, complete removal (100.00%) of MG was observed at 30 min of the reaction time by UV/H2O2/Fe2+ employing [MG]0 = 10 mg/L, [H2O2]0 = 10 mM, [Fe2+]0 = 2.5 mg/L, and [pH]0 = 3.0. For the UV/H2O2 process, the degradation efficiency was higher at pH 6.0 than at pH 3.0 as the k obs values were 0.0873 and 0.0690 min−1, respectively. However, UV/H2O2/Fe2+ showed higher reactivity at pH 3.0 than at pH 6.0. Chloride and nitrate ions slightly inhibited the removal efficiency of MG by both UV/H2O2 and UV/H2O2/Fe2+ processes. Moreover, three degradation products (DPs) of MG, (i) 4-dimethylamino-benzophenone (DABP), (ii) 4-amino-benzophenone (ABP), and (iii) 4-dimethylamino-phenol (DAP), were identified by GC-MS during the UV/H2O2 treatment. These DPs were found to demonstrate higher aquatic toxicity than the parent MG, suggesting that researchers should focus on the removal of target pollutants as well as their DPs. Nevertheless, the results of this study indicate that both UV/H2O2 and UV/H2O2/Fe2+ processes could be implemented to alleviate the harmful environmental impacts of dye and textile industries. [ABSTRACT FROM AUTHOR]

The direct utilization of solar energy for the artificial photosynthesis of hydrogen peroxide (H2O2) provides a reliable approach for producing this high-value green oxidant. Here we report on the utility of high-entropy oxide (HEO) semiconductor as an all-in-one photocatalyst for visible light-driven H2O2 production directly from H2O and atmospheric O2 without the need of any additional cocatalysts or sacrificial agents. This high-entropy photocatalyst contains eight earth-abundant metal elements (Ti/V/Cr/Nb/Mo/W/Al/Cu) homogeneously arranged within a single rutile phase, and the intrinsic chemical complexity along with the presence of a high density of oxygen vacancies endow high-entropy photocatalyst with distinct broadband light harvesting capability. An efficient H2O2 production rate with an apparent quantum yield of 38.8% at 550 nm can be achieved. The high-entropy photocatalyst can be readily assembled into floating artificial leaves for sustained on-site production of H2O2 from open water resources under natural sunlight irradiation. An "all-in-one" high-entropy semiconductor photocatalyst enables the photocatalytic production of H2O2 from H2O and O2 under visible light without any external cocatalysts or sacrificial agents [ABSTRACT FROM AUTHOR]

Reactive oxygen species (ROS) are physiological byproducts of neuronal metabolism. However, an imbalance between ROS generation and antioxidant capacity, often driven by dysregulated pro-oxidant enzymes like nicotinamide adenine dinucleotide phosphate oxidases (NOX), can result in deleterious oxidative stress. This oxidative stress is a critical factor in the pathogenesis of neurodegenerative diseases. While interventions with broad-spectrum antioxidants have demonstrated limited efficacy, the modulation of endogenous antioxidant mechanisms presents a promising therapeutic avenue. Here, we investigated the potential of the neuroprotective hormone prolactin to mitigate oxidative stress and subsequent neuronal cell death. Prolactin protected primary mouse hippocampal neurons from hydrogen peroxide (H2O2)-induced oxidative damage. Prolactin reduced ROS levels, lipid peroxidation, and apoptosis, and its effects were occluded by a specific prolactin receptor antagonist (G129R-hPRL). Mechanistically, prolactin suppressed H2O2-induced mRNA upregulation of pro-oxidative Nox4 and pro-apoptotic Bax. Moreover, prolactin induced nuclear factor kappa B (NF-κB) nuclear translocation, and the inhibition of the NF-κB signaling pathway abolished the neuroprotective and transcriptional effects of prolactin, indicating its central role in prolactin-mediated protection. Our findings indicate that prolactin exerts potent antioxidant and neuroprotective effects by modulating the expression of Nox4 and Bax, thereby reducing ROS generation and neuronal apoptosis. This study underscores the therapeutic potential of prolactin in attenuating oxidative stress and suggests a possible role in the treatment of neurodegenerative diseases. [ABSTRACT FROM AUTHOR]

Two‐dimensional covalent organic frameworks (2D‐COFs) have recently emerged as fascinating scaffolds for solar‐to‐chemical energy conversion because of their customizable structures and functionalities. Herein, two tris(triazolo)triazine‐based COF materials (namely COF‐JLU51 and COF‐JLU52) featuring large surface area, high crystallinity, excellent stability and photoelectric properties were designed and constructed for the first time. Remarkably, COF‐JLU51 gave an outstanding H2O2 production rate of over 4200 μmol g−1 h−1 with excellent reusability in pure water and O2 under one standard sun light, that higher than its isomorphic COF‐JLU52 and most of the reported metal‐free materials, owing to its superior generation, separation and transport of photogenerated carriers. Experimental and theoretical researches prove that the photocatalytic process undergoes a combination of indirect 2e− O2 reduction reaction (ORR) and 4e− H2O oxidation reaction (WOR). Specifically, an ultrahigh yield of 7624.7 μmol g−1 h−1 with apparent quantum yield of 18.2 % for COF‐JLU52 was achieved in a 1 : 1 ratio of benzyl alcohol and water system. This finding contributes novel, nitrogen‐rich and high‐quality tris(triazolo)triazine‐based COF materials, and also designate their bright future in photocatalytic solar transformations. [ABSTRACT FROM AUTHOR]

Efficient activation of hydrogen peroxide (H2O2) through biomimetic catalysis still faces a major challenge. In this work, inspired by the catalytic pocket of natural peroxidase, Cu single atom (CuSA) and AuCu nanoparticles (AuCuNPs) anchored on nitrogen‐doped carbon skeleton (CuSA‐AuCuNPs/NC) serve as dual active sites that significantly accelerate the charge transfer process and thus achieve efficient H2O2 activation. Meanwhile, the experimental and theoretical calculations show that the well‐established electronic communication effect between CuSA and AuCuNPs results in moderate electronic modifications to CuSA, which promotes the heterolysis of H2O2 and the timely desorption of H2O. As a proof of concept, CuSA‐AuCuNPs/NC show remarkable performance in detecting uranyl ions in seawater. This work provides new insights into the H2O2 activation for colorimetric sensing. [ABSTRACT FROM AUTHOR]

Two‐dimensional covalent organic frameworks (2D‐COFs) have recently emerged as fascinating scaffolds for solar‐to‐chemical energy conversion because of their customizable structures and functionalities. Herein, two tris(triazolo)triazine‐based COF materials (namely COF‐JLU51 and COF‐JLU52) featuring large surface area, high crystallinity, excellent stability and photoelectric properties were designed and constructed for the first time. Remarkably, COF‐JLU51 gave an outstanding H2O2 production rate of over 4200 μmol g−1 h−1 with excellent reusability in pure water and O2 under one standard sun light, that higher than its isomorphic COF‐JLU52 and most of the reported metal‐free materials, owing to its superior generation, separation and transport of photogenerated carriers. Experimental and theoretical researches prove that the photocatalytic process undergoes a combination of indirect 2e− O2 reduction reaction (ORR) and 4e− H2O oxidation reaction (WOR). Specifically, an ultrahigh yield of 7624.7 μmol g−1 h−1 with apparent quantum yield of 18.2 % for COF‐JLU52 was achieved in a 1 : 1 ratio of benzyl alcohol and water system. This finding contributes novel, nitrogen‐rich and high‐quality tris(triazolo)triazine‐based COF materials, and also designate their bright future in photocatalytic solar transformations. [ABSTRACT FROM AUTHOR]

A novel glow-type chemiluminescence (CL)-based nanosensing system was developed for sensitive and rapid point-of-care testing (POCT) of H2O2 in food. CuSe nanoparticles (CuSeNPs) have excellent peroxidase-like activity. After being modified with thiols of 4-mercaptophenylboronic acid (MBA) (CuSeNPs@MBA), luminol can be catalyzed to produce long-lasting CL in the presence of H2O2. The possible reason for the long-lasting glow-type CL behavior was explored. Under the optimized condition, H2O2 can be sensitively detected with improved repeatability. The limit of detection is as low as 0.30 μM. To meet the requirement of in situ and outside of laboratory detection, a 3D-printed portable device was designed which can eliminate the environmental interference to improve detection accuracy. The developed multifunctional platform also has the advantages of simple operation and low cost, suggesting its great potential for applications in food and agricultural fields. [ABSTRACT FROM AUTHOR]

Formic acid is considered a promising hydrogen carrier. Biomass‐derived formic acid can be obtained by oxidative decomposition of sugars. This study explored the production of formic acid from cellobiose, a disaccharide consisting of d‐glucose linked by β‐glycosidic bonds using heterogeneous catalysts under mild reaction conditions. The use of alkaline earth metal oxide solid base catalysts like CaO and MgO in the presence of hydrogen peroxide could afford formic acid from cellobiose at 343 K. While CaO gave 14 % yield of formic acid, the oxide itself was converted to a harmful metal peroxide, CaO2 after the reaction. In contrast, MgO could produce formic acid without the formation of the metal peroxide. The difficulty in selectively synthesizing formic acid from cellobiose using these solid base catalysts was due to the poor conversion of cellobiose to glucose. Using a combination of solid acid and base catalysts, a high formic acid yield of 33 % was obtained under mild reaction conditions due to the quantitative hydrolysis of cellobiose to glucose by a solid acid followed by the selective decomposition of glucose to formic acid by a solid base. [ABSTRACT FROM AUTHOR]

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

Redox reactions, involving electron transfer, are critical to human physiology. However, progress in understanding redox metabolism is hindered by flawed analytical methods. This review highlights emerging techniques that promise to revolutionize redox research, enhancing our comprehension of human health and disease. Oxygen, vital for aerobic metabolism, also produces reactive oxygen species (ROS), such as superoxide and hydrogen peroxide. While historically seen as harmful, ROS at low concentrations are now recognized as key regulators of cell signaling. A balance between ROS and antioxidants, known as redox balance, is crucial, and deviations can lead to oxidative stress. Recent studies have distinguished beneficial "oxidative eustress" from harmful "oxidative distress." New techniques, such as advanced mass spectrometry and high‐throughput immunoassays, offer improved accuracy in measuring redox states and oxidative damage. These advancements are pivotal for understanding redox signaling, cysteine oxidation, and their implications for disease. Looking ahead, the development of precision redox medicine could lead to better treatments for oxidative stress‐related diseases and foster interventions promoting health. [ABSTRACT FROM AUTHOR]

Quinazolines and their derivatives occur in various natural products and pharmaceuticals, and thus, various methods of synthesizing quinazolines have been explored. They have traditionally been synthesized via two‐component reactions, but these strategies often suffer from the unavailability of the starting materials and limited substrate scopes. To overcome these problems, three‐component reactions using additional N sources were developed. Aldehydes were initially used in these reactions, but alcohols are greener and less toxic than aldehydes. However, the previously reported methods involving the use of alcohols require the utilization of transition metal catalysts, ultrahigh temperatures, and extended durations. Thus, an efficient, practical method of synthesizing quinazolines using alcohol is desirable. A facile one‐pot three‐component method of synthesizing quinazolines utilizing alcohols, 2‐aminobenzoketones, and ammonium acetate is reported for the first time, using active MnO2 and tert‐butyl hydrogen peroxide (TBHP) as synergistic oxidants. MnO2 and TBHP play dual roles: First, they oxidize the alcohol to the aldehyde and then facilitate the transformation of the intermediate into the product. During alcohol oxidation, the synergistic effect of MnO2 and TBHP is particularly evident. The aldehydes generated in situ via alcohol oxidation undergo immediate subsequent reactions, thereby minimizing their volatilization and side reactions, such as oxidation and polymerization. [ABSTRACT FROM AUTHOR]

Pulmonary artery endothelial cells (PAECs) are a major contributor to hypoxic pulmonary hypertension (PH) due to the possible roles of reactive oxygen species (ROS). However, the molecular mechanisms and functional roles of ROS in PAECs are not well established. In this study, we first used Amplex UltraRed reagent to assess hydrogen peroxide (H2O2) generation. The result indicated that hypoxic exposure resulted in a significant increase in Amplex UltraRed-derived fluorescence (i.e., H2O2 production) in human PAECs. To complement this result, we employed lucigenin as a probe to detect superoxide (O2−) production. Our assays showed that hypoxia largely increased O2− production. Hypoxia also enhanced H2O2 production in the mitochondria from PAECs. Using the genetically encoded H2O2 sensor HyPer, we further revealed the hypoxic ROS production in PAECs, which was fully blocked by the mitochondrial inhibitor rotenone or myxothiazol. Interestingly, hypoxia caused an increase in the migration of PAECs, determined by scratch wound assay. In contrast, nicotine, a major cigarette or e-cigarette component, had no effect. Moreover, hypoxia and nicotine co-exposure further increased migration. Transfection of lentiviral shRNAs specific for the mitochondrial Rieske iron–sulfur protein (RISP), which knocked down its expression and associated ROS generation, inhibited the hypoxic migration of PAECs. Hypoxia largely increased the proliferation of PAECs, determined using Ki67 staining and direct cell number accounting. Similarly, nicotine caused a large increase in proliferation. Moreover, hypoxia/nicotine co-exposure elicited a further increase in cell proliferation. RISP knockdown inhibited the proliferation of PAECs following hypoxia, nicotine exposure, and hypoxia/nicotine co-exposure. Taken together, our data demonstrate that hypoxia increases RISP-mediated mitochondrial ROS production, migration, and proliferation in human PAECs; nicotine has no effect on migration, increases proliferation, and promotes hypoxic proliferation; the effects of nicotine are largely mediated by RISP-dependent mitochondrial ROS signaling. Conceivably, PAECs may contribute to PH via the RISP-mediated mitochondrial ROS. [ABSTRACT FROM AUTHOR]

A benzothiazole-based derivative aggregation-induced emission (AIE) fluorescent 'turn-on' probe named 2-(2-((4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)benzyl)oxy)phenyl)benzo[d]thiazole (probe BT-BO) was developed and synthesized successfully for detecting hydrogen peroxide (H2O2) in living cells. The synthesis method of probe BT-BO is facile. Probe BT-BO demonstrates a well-resolved emission peak at 604 nm and the ability to prevent the interference of reactive oxygen species (ROS), various metal ions and anion ions, and good sensitivity. Additionally, the probe boasts impressive pH range versatility, a fast response time to H2O2 and low cytotoxicity. Finally, probe BT-BO was applied successfully to image A549 and Hep G2 cells to monitor both exogenous and endogenous H2O2. [ABSTRACT FROM AUTHOR]

The photocatalytic oxygen reduction reaction (ORR), particularly the one-step two-electron (2e−) pathway, is a highly promising strategy for efficient and selective hydrogen peroxide (H2O2) synthesis. However, constructing efficient photocatalysts to achieve a one-step 2e− ORR process remains a significant challenge. Herein, we developed an efficient photocatalyst by incorporating pyrimidine units into benzotrithiophene-based covalent organic framework (BTT-MD-COF), enabling the photosynthesis of H2O2 via the one-step 2e− ORR pathway with O2 and water. Under visible-light irradiation, BTT-MD-COF exhibited a high H2O2 production rate of up to 5691.2 µmol·h−1·g−1. Further experimental results and theoretical studies revealed that the introduction of pyrimidine units accelerates the separation of photoinduced electron–hole pairs and promotes Yeager-type O2 adsorption, which alters the two-step 2e− ORR process to the direct one-step 2e− process. This work offers a new avenue to create metal-free catalysts for efficient photosynthesis of H2O2. [ABSTRACT FROM AUTHOR]

Nicotinamide adenine dinucleotide (NAD+/NADH) pools homeostasis is recognized as an Achilles' Heel in tumor metabolism reprogramming. However, mitochondria can enable cancer cells to overcome NADH exhaustion by providing NAD+ precursors and/or intermediates, thus promoting their survival rate and potentially driving uncontrollable proliferation. Here, a synergistic intervention NAD+/NADH homeostasis and mitochondrial metabolism strategy with magnetic resonance imaging (MRI)/photoacoustic imaging (PAI) are developed to address grand challenge of metabolic reprogramming for antitumor bioenergetic therapy. A mitochondrial-targeted cascade amplification nanoplatform ([β-MQ]TRL), triggered by NAD(P)H: quinone oxidoreductase-1 (NQO1), can enable a continuous depletion of cytosol NADH until cell death. The end-product, hydrogen peroxide (H2O2), can be further catalytically converted to higher toxic ·OH in proximity to mitochondria based on [β-MQ]TRL mediated Fenton-like reaction, hijacking tumorigenic energy sources and leading to mitochondrial dysfunction. Additionally, the mild thermal ablation enabled by [β-MQ]TRL further amplifies this cascade reaction to effectively prevent tumor metastasis and recurrence. This synchronous intervention strategy with MRI/PAI establishes unprecedented efficiency in antitumor bioenergetic therapy in vivo, which shows excellent promise for clinical application. [ABSTRACT FROM AUTHOR]

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In situ synthesis of novel hybrid organic–inorganic nanopetals (HNPs) of Copper (Cu2+) and gold-conjugated hemoglobin (Au@Hb) is reported. The presence of Au within the protein matrix prevents the formation of a flower-like assembly of the formed nanopetals of Au@Hb and Cu2+ via the co-precipitation method. Morphological, chemical, and electrocatalytic activities of in situ synthesized Au@Hb-Cu HNPs were examined systematically. The hybrid nanopetal (Au@Hb-Cu HNP)-modified screen-printed PET electrodes show enhanced electrocatalytic activity toward the oxidation of H2O2 compared to electrodes modified with Hb-copper hybrid nanoflowers (Hb-Cu HNFs) without Au conjugation. The proposed biosensor exhibits excellent electrochemical performance with broad linear responses over a H2O2 concentration ranging from 5 to 1000 µM (R2 = 0.99) and showed a lower detection limit of 1.46 µM at 0.30 V vs. pseudo Ag/AgCl. Enhanced electrochemical performance is attributed to heterogeneous active sites over hybrid nanopetal surfaces. Moreover, the hybrid nanopetal–modified electrodes showed excellent stability and anti-interference performance in the presence of ascorbic acid, uric acid, fructose, and glucose. These results demonstrate that Au@Hb-Cu HNPs offer a better and more promising alternative for the electrochemical detection of H2O2 sensitively. [ABSTRACT FROM AUTHOR]

Melanin, particularly eumelanin, is commonly viewed as an efficient antioxidant and photoprotective pigment. Nonetheless, the ability of melanin to photogenerate reactive oxygen species and sensitize the formation of cyclobutane pyrimidine dimers may contribute to melanin‐dependent phototoxicity. The phototoxic potential of melanin depends on a variety of factors, including molecular composition, redox state, and degree of aggregation. Using complementary spectroscopic and analytical methods we analyzed the physicochemical properties of Dopa‐melanin, a synthetic model of eumelanin, subjected to oxidative degradation induced by aerobic photolysis or exposure to 0.1 M hydrogen peroxide. Both modes of oxidative degradation were accompanied by dose‐dependent bleaching of melanin and irreversible modifications of its paramagnetic, ion‐ and electron‐exchange and antioxidant properties. Bleached melanin exhibited enhanced efficiency to photogenerate singlet oxygen in both UVA and short‐wavelength visible light. Although chemical changes of melanin subunits, including a relative increase of DHICA content and disruption of melanin polymer induced by oxidative degradation were considered, these two mechanisms may not be sufficient for a satisfactory explanation of the elevated photosensitizing ability of the bleached eumelanin. This study points out possible adverse changes in the photoprotective and antioxidant properties of eumelanin that could occur in pigmented tissues after exposure to high doses of intense solar radiation. [ABSTRACT FROM AUTHOR]

Catalysts are widely used in research and in industrial applications to enable or to accelerate chemical reactions. One application is monopropellant thrusters for space propulsion systems, which use hydrogen peroxide (H2O2) as liquid propellant. The decomposition of liquid hydrogen peroxide into water and oxygen gas, which then finally generates the thrust, can be achieved using noble metal catalysts like platinum and iridium. In this study, iridium–platinum alloys were deposited onto ceramic pellets by a controlled magnetron sputtering process with different parameters. Selected parameters result in coated layers featuring an atomic structure of closed- and/or open-shell microstructures. The catalytic performance of these coated pellets was evaluated in laboratory experiments. The reactivity of sputtered iridium–platinum layers for the decomposition of H2O2 was found to be significantly higher with respect to layers of pure iridium coatings. This can be explained by the better reactivity of iridium–platinum alloys, combined with the active control of the surface morphology and the microstructure of the alloy coatings. [ABSTRACT FROM AUTHOR]

The improper disposal of uranium mine tailings and smelting wastewater poses significant environmental hazards, including contamination of water bodies and soil, and potential health risks to humans through the accumulation of uranium in bones and organs. This study examines the removal of hexavalent uranium (U(VI)) from water using biochar derived from agricultural waste enhanced by hydrogen peroxide (H2O2) and magnetization modifications involving the incorporation of Fe3O4 nanoparticles onto the biochar surface. The adsorption capacities were evaluated through batch experiments, and the mechanisms were analyzed using SEM, FT-IR, XPS, and BET surface analysis. These modifications were found to significantly increase the biochar's specific surface area from 17.606 m2/g to 195.62 m2/g and pore volume from 0.037 cm3/g to 0.132 cm3/g, and surface enrichment with oxygen-containing functional groups, particularly carboxyl groups. The inherent adsorption efficiency of biochar for U(VI) is significantly enhanced by these modifications, with the adsorption capacities of H2O2-modified (HBC) and magnetized HBC (MBC) reaching 69.50 mg/g and 77.58 mg/g, respectively. The adsorption mechanisms of BC, HBC, and MBC for U(VI) involve complexation reactions where hydroxyl and carboxyl groups, among other oxygen-containing functional groups on the biochar, interact with uranyl ions. HBC and MBC exhibit enhanced complexation due to higher carboxyl content, leading to improved U(VI) adsorption. Additionally, the presence of iron-containing functional groups on the surface of MBC contributes to electrostatic interactions and facilitates complexation reactions between Fe-O and uranyl ions, enhancing the overall adsorption process. These findings highlight the potential of modified biochar for the removal of U(VI) from water, particularly for the treatment of mine tailings and smelting wastewater, with significant implications for industrial applications in environmental remediation. [ABSTRACT FROM AUTHOR]

Deep eutectic solvent (DES) has been considered as a useful catalyst and reaction medium for various organic transformations. Herein, we report the catalytic application of novel deep eutectic solvent- based surfactant (DES surfactant) for the selective and fast oxidation of alcohols to aldehydes. The readily accessible DES surfactants (FeCl3/BHDC) was prepared using inexpensive ferric chloride (FeCl3) and benzyl hexadecyl dimethyl ammonium chloride in a simple manner. The synthesized FeCl3/BHDC was characterized using various techniques, including, FTIR spectroscopy, thermal gravimetric analysis (TGA), scanning electron microscopy (SEM), and energy- dispersive X-ray spectroscopy (EDS) to determine its structure. The catalytic activity of FeCl3/BHDC in the selective oxidation of various alcohols to corresponding aldehyde derivative was investigated. The results showed the reaction could be completed within very short reaction times ranging from 2 to 15 min, while achieving good to excellent yields. This protocol offers a facile strategy and excellent efficiency in selectively oxidizing various alcohol derivatives to their respective aldehydes and ketones, utilizing hydrogen peroxide in the presence of catalytic DES surfactant. [ABSTRACT FROM AUTHOR]

Due to the fusion of culinary cultures, chili products have gained widespread popularity among consumers. Capsaicin, the primary compound responsible for the spiciness of chili products, serves as a pivotal parameter in assessing the quality of chili peppers. A three-dimensional (3D) cell-based electrochemical sensor was developed to detect capsaicin by monitoring the release of hydrogen peroxide (H2O2). The working electrode utilized in this study was a screen-printed carbon electrode (SPCE) that had been modified with AuPtNPs/ZIF-8-RGO. Encapsulation of HepG2 cells within a 4.0 wt% sodium alginate gel enabled their immobilization onto the working electrode, thus serving as the biometric element for signal recording via the amperometric i-t method. H2O2 kit assays showed that H2O2 release increased with increasing capsaicin concentration over a range of concentrations. With a detection limit of 0.848 μM, the developed biosensor effectively detected capsaicin at concentrations that varied from 10 μM to 120 μM. The sensor that was developed displayed exceptional sensitivity, stability, and reliability, offering a novel method for monitoring capsaicin level in food. [ABSTRACT FROM AUTHOR]

Cryopreservation is a reliable technique for the long-term storage and preservation of embryogenic cells, maintaining their viability without loss of their embryogenic capacity. However, the large-scale conservation of grapevine embryogenic lines in cryobanks remains limited. A significant challenge is understanding somatic cell rejuvenation. Here, we investigate the encapsulation/dehydration and encapsulation/vitrification for cryopreserving embryogenic material. Cell rejuvenation and enhanced embryogenic competence were observed after cryopreservation, as evidenced through structural cellular changes observed by histology and electron scanning microscopy. Results showed that cryopreserved samples of 110-Richter, Riesling, and Tempranillo using encapsulation/dehydration had better survival rates, averaging 81%, 62%, and 48%, respectively, while encapsulation/vitrification yielded lower survival rates, averaging 58%, 42%, and 32%, respectively. Cryopreservation also improved post-thaw recovery and regeneration efficiency assessed through regrowth of proembryogenic masses and somatic embryo conversion reaching 54–72% against 11–17% in control samples. Cryopreservation triggered changes in gene expression patterns and exhibited considerable increase at genotype-specific basis of 1.5- to 4.5-fold in SERK1, BBM, and WOX associated to embryogenic competence as well as in ChitIV and LEA involved in stress response. Membrane stability index, hydrogen peroxide, and proline contents were used as indicators of oxidative stress uncovering a key role of an osmotic trans-priming effect leading to cryotolerance. Our finding highlighted that cryopreservation enhances embryogenic capacity in senescent callus and probably acts as a screening process allowing safe maintenance of proembryogenic cells and promoting their recovery. This study provides a high throughput innovation to set up cryolines for cell rejuvenation of grapevine and other important plant species. [ABSTRACT FROM AUTHOR]

Hydrogen peroxide (H2O2) is naturally produced by plant cells during normal development and serves as a messenger that regulates cell metabolism. Despite its importance, the relationship between hydrogen peroxide and the target of rapamycin (TOR) pathway, as well as its impact on cell division, has been poorly analyzed. In this study, we explore the interaction of H2O2 with TOR, a serine/threonine protein kinase that plays a central role in controlling cell growth, size, and metabolism in Arabidopsis thaliana. By applying two concentrations of H2O2 exogenously (0.5 and 1 mM), we could correlate developmental traits, such as primary root growth, lateral root formation, and fresh weight, with the expression of the cell cycle gene CYCB1;1, as well as TOR expression. When assessing the expression of the ribosome biogenesis-related gene RPS27B, an increase of 94.34% was noted following exposure to 1 mM H2O2 treatment. This increase was suppressed by the TOR inhibitor torin 2. The elimination of H2O2 accumulation with ascorbic acid (AA) resulted in decreased cell division as well as TOR expression. The potential molecular mechanisms associated with the effects of H2O2 on the cell cycle and TOR expression in roots are discussed in the context of the results. [ABSTRACT FROM AUTHOR]

Fumarylacetoacetate hydrolase (FAH) catalyzes the final step of the tyrosine degradation pathway. In this study, we isolated and characterized two homologous BnaFAH genes in Brassica napus L. variant Westar, and then used CRISPR/Cas9-mediated targeted mutagenesis to generate a series of transgene-free mutant lines either with single or double-null bnafah alleles. Among these mutant lines, the aacc (bnafah) double-null mutant line, rather than the aaCC (bnaa06fah) mutant line, exhibited programmed cell death (PCD) under short days (SD). Histochemical staining and content measurement confirmed that the accumulation of reactive oxygen species (ROS) in bnafah was significantly higher than that in bnaa06fah. To further elucidate the mechanism of PCD, we performed transcriptomic analyses of bnaa06fah and bnafah at different SD stages. A heatmap cluster of differentially expressed genes (DEGs) revealed that PCD may be related to various redox regulatory genes involved in antioxidant activity, ROS-responsive regulation and calcium signaling. Combined with the results of previous studies, our work revealed that the expression levels of BnaC04CAT2, BnaA09/C09SAL1, BnaA08/C08ACO2, BnaA07/C06ERO1, BnaA08ACA1, BnaC04BIK1, BnaA09CRK36 and BnaA03CPK4 were significantly different and that these genes might be candidate hub genes for PCD. Together, our results underscore the ability of different PCD phenotypes to alter BnaFAH orthologs through gene editing and further elucidated the molecular mechanisms of oxidative stress-induced PCD in plants. [ABSTRACT FROM AUTHOR]

S-nitrosoglutathione reductase (GSNOR) is involved in the response to cadmium (Cd) exposure. In this study, the plants of mutant (gsnor1-3) with lossing-function of- and over-expression (GSNOROE5) of GSNOR were used to clear the role of GSNOR in Cd tolerance. GSNOR activity increased through upregulating the expression of the AtGSNOR gene and protein in Arabidopsis thaliana under Cd stress, which attenuated Cd tolerance. Oxidative damage was more serious in GSNOROE5 and was alleviated in gsnor1-3 under Cd stress, compared with Col-0. Induction of GSNOR facilitated H2O2 accumulation but inhibited catalase (CAT) activity in shoots under Cd stress. This phenotype was eliminated by 3-amino-1,2,4-triazole (3-AT), a CAT inhibitor. In addition, the expressions of AtCAT1 and AtCAT2 were down-regulated with increasing GSNOR activity under Cd stress. This suggested that GSNOR was involved in the accumulation of hydrogen peroxide (H2O2) through regulating CAT expression and activity under Cd exposure. Furthermore, Cd tolerance and CAT activity were improved by spraying S-nitrosoglutathione (GSNO) onto the surface of the leaves. The in vitro activity of CAT increased with GSNO concentration until a GSNO/CAT ratio of 2 was reached. Thus, CAT activity was relative to GSNOR through regulating the expression and S-nitrosylation level of proteins. In summary, the Cd-induced promotion of GSNOR activity aggravated Cd toxicity in plants by mediating H2O2 accumulation controlled by CAT. [ABSTRACT FROM AUTHOR]

Developing efficient electrocatalysts for acidic electrosynthesis of hydrogen peroxide (H2O2) holds considerable significance, while the selectivity and stability of most materials are compromised under acidic conditions. Herein, we demonstrate that constructing amorphous platinum–selenium (Pt–Se) shells on crystalline Pt cores can manipulate the oxygen reduction reaction (ORR) pathway to efficiently catalyze the electrosynthesis of H2O2 in acids. The Se2‒Pt nanoparticles, with optimized shell thickness, exhibit over 95% selectivity for H2O2 production, while suppressing its decomposition. In flow cell reactor, Se2‒Pt nanoparticles maintain current density of 250 mA cm−2 for 400 h, yielding a H2O2 concentration of 113.2 g L−1 with productivity of 4160.3 mmol gcat−1 h−1 for effective organic dye degradation. The constructed amorphous Pt–Se shell leads to desirable O2 adsorption mode for increased selectivity and induces strain for optimized OOH* binding, accelerating the reaction kinetics. This selenization approach is generalizable to other noble metals for tuning 2e‒ ORR pathway. Developing efficient catalysts for acidic electrosynthesis of H2O2 is desirable, while most materials are compromised in acidic conditions. Here, the authors report that constructing amorphous Pt–Se shells on crystalline Pt cores can regulate the reaction pathway to efficiently produce H2O2 in acid. [ABSTRACT FROM AUTHOR]

Wound infection is a major factor affecting the speed and quality of wound healing. While hydrogen peroxide (H2O2) is recognized for its antibacterial capacity and facilitation of wound healing, its administration requires careful dosage differentiation. Inappropriately matched dosages can protract the healing of infected wounds. Herein, a calcium peroxide‐based hydrogel (CPO‐Alg hydrogel) is fabricated to enable a biphasic tapered release of H2O2, ensuring robust initial antimicrobial activity followed by sustained promotion of cellular proliferation of wound healing. The design of the hydrogel allowed for the calcium peroxide nanoparticles (CPO NPs) being in two spatial niches within the gel framework. When applied to infectious wounds, CPO NPs with weak constraints are promptly released out of the gel, penetrating into infected regions to serve as antibacterial agents that eliminate bacteria and biofilms at high concentrations. Conversely, the entrapped CPO NPs structurally integrated into the gel remain confined, thus gradually degrading and allowing a mild release of H2O2 through hydrolysis in a moist environment that contributes to the cell growth in the later stage. The CPO‐Alg hydrogel represents an innovative and practical solution for the antimicrobial protection of chronic wounds, offering promising prospects for advancing wound healing. [ABSTRACT FROM AUTHOR]

Atherosclerosis (AS) poses a significant threat to human life and health. However, conventional antiatherogenic medications exhibit insufficient targeting precision and restricted therapeutic effectiveness. Moreover, during the progression of AS, macrophages undergo polarization toward the proinflammatory M1 phenotype and generate reactive oxygen species (ROS) to accelerate the occurrence of inflammatory storms, and ingest excess lipids to form foam cells by inhibiting cholesterol efflux. In our study, we developed a macrophage membrane-functionalized hollow mesoporous manganese dioxide nanomedicine (Col@HMnO2-MM). This nanomedicine has the ability to evade immune cell phagocytosis, enables prolonged circulation within the body, targets the inflammatory site of AS for effective drug release, and alleviates the inflammatory storm at the AS site by eliminating ROS. Furthermore, Col@HMnO2-MM has the ability to generate oxygen autonomously by breaking down surplus hydrogen peroxide generated at the inflammatory AS site, thereby reducing the hypoxic microenvironment of the plaque by downregulating hypoxia-inducible factor (HIF-1α), which in turn enhances cholesterol efflux to inhibit foam cell formation. In an APOE−/− mouse model, Col@HMnO2-MM significantly reduced inflammatory factor levels, lipid storage, and plaque formation without significant long-term toxicity. In summary, this synergistic treatment significantly improved the effectiveness of nanomedicine and may offer a novel strategy for precise AS therapy. [ABSTRACT FROM AUTHOR]

Background: Quinic acid (QA), a cyclitol and cyclohexanecarboxylic acid, is a natural product that is present and can be isolated from edible herbals like tea, coffee and several fruits and vegetables. It was previously reported that QA exerted antioxidant and neuroprotective activity against dementia. However, it was not tested for its neuroprotective potential against Huntington's disease (HD). Since aging related disorders are greatly linked to oxidative stress conditions, we focused on testing the oxidative stress resistant activity and protective effect of QA against the development of HD by using the multicellular Caenorhabditis elegans (C. elegans) worm model. Methods: Firstly, QA was tested for its oxidative stress resistant properties. In survival assay, wild type and mutant skn-1 and daf-16 worms were exposed to oxidative stress conditions by using H2O2. Activation of SKN-1 pathway and expression of its downstream genes gcs-1 and gst-4 were also tested. Secondly, the effect of QA was evaluated on HD by testing its ability to decrease the formation of polyQ150 aggregates. Furthermore, its effect on the accumulation of polyglutamine (polyQ35 and polyQ40 aggregates) was tested. Results: Here we report that QA could improve the survival of C. elegans after exposure to oxidative stress caused by H2O2 while also exerting antioxidant effects through the activation of SKN-1/Nrf2 pathway. Moreover, QA could be a potential candidate to protect against HD due to its effects on decreasing the formation of polyQ150, polyQ35 and polyQ40 aggregates. Conclusions: This study highlights the importance of QA as a natural compound in defending against oxidative stress and the development of neurodegenerative diseases like HD. [ABSTRACT FROM AUTHOR]

Supramolecular polymers possess great potential in catalysis owing to their distinctive molecular recognition and dynamic crosslinking features. However, investigating supramolecular electrocatalysts with high efficiency in oxygen reduction reaction to hydrogen peroxide (ORHP) remains an unexplored frontier. Herein, we present organic polymers for ORHP by introducing cyclodextrin-containing noncovalent building blocks, affording these supramolecules with abundant dynamic bonds. The electronic states and reaction kinetics are further well-modulated via a host-guest strategy, resulting in appropriate regional electron binding force and controllable chemical activity. Notably, integrating supramolecular units into phenyl group-containing model covalent polymer achieves a production rate of 9.14 mol g−1cat h−1, with 98.01% Faraday efficiency, surpassing most reported metal-free electrocatalysts. Moreover, the dynamic bonds in supramolecular catalysts can effectively regulate the binding ability of oxygen intermediates, leading to high reactivity and selectivity for the 2e− pathway. Supported by theory calculation and in situ experiment, C atoms (site–1) adjacent to the –C = N (N) group are potential active sites. This work pioneers host-guest strategy and provides inspiring ideas for the ORHP process. Dynamic bonds offer unique advantages of adaptability and selectivity, yet, supramolecular electrocatalysts specifically tailored for 2e− pathway remain unexplored. Here, the authors report a host-guest strategy that employs dynamic bonds to adjust electronic states through dual-channel regulation. [ABSTRACT FROM AUTHOR]

(3‐(4‐Fluorophenyl)oxyran‐2‐yl)(naphthalene‐2‐yl)methanone 2 was prepared from the reaction of 3‐(4‐fluorophenyl)‐1‐(naphthalen‐2‐yl)prop‐2‐en‐1‐one (1) with hydrogen peroxide and reacted with different nucleophiles such as hydrazine hydrate, phenyl hydrazine, thiosemicarbazide to give 4‐hydroxy‐1H‐pyrazole derivatives 3a,b‐4. Also, compound 2 was treated with hydroxylamine hydrochloride to give the substituted 2,3‐dihydroisoxazole 5. Similarly, compound 2 was treated with carbon disulfide, phenyl isothiocyanate, and phenyl isocyanate to give the corresponding compounds 6–8. Various spectroscopic techniques and elemental analysis were used to determine the molecular structures of the new derivatives. All the new analogs were screened against five human pathogenic microbial strains: Escherichia coli and Pseudomonas aeruginosa as Gram‐negative bacteria, Bacillus subtilis and Staphylococcus aureus as Gram‐positive bacteria and the yeast Candida albicans using agar diffusion method. Compound 4 exhibited moderate antimicrobial activity against all the tested microorganisms compared to positive control ciprofloxacin and fluconazole. On the other hand, the free radical scavenging activity of the new compounds using DPPH assay protocol revealed that most of the compounds have a weak reducing activity. Moreover, compounds 4 and 8 were docked against 1KZN protein (DNA gyrase), 3FYV and 5V5Z showing the ability to interact with key amino acid residues and the potential to act as inhibitors. [ABSTRACT FROM AUTHOR]

Atherosclerosis (AS) poses a significant threat to human life and health. However, conventional antiatherogenic medications exhibit insufficient targeting precision and restricted therapeutic effectiveness. Moreover, during the progression of AS, macrophages undergo polarization toward the proinflammatory M1 phenotype and generate reactive oxygen species (ROS) to accelerate the occurrence of inflammatory storms, and ingest excess lipids to form foam cells by inhibiting cholesterol efflux. In our study, we developed a macrophage membrane-functionalized hollow mesoporous manganese dioxide nanomedicine (Col@HMnO2-MM). This nanomedicine has the ability to evade immune cell phagocytosis, enables prolonged circulation within the body, targets the inflammatory site of AS for effective drug release, and alleviates the inflammatory storm at the AS site by eliminating ROS. Furthermore, Col@HMnO2-MM has the ability to generate oxygen autonomously by breaking down surplus hydrogen peroxide generated at the inflammatory AS site, thereby reducing the hypoxic microenvironment of the plaque by downregulating hypoxia-inducible factor (HIF-1α), which in turn enhances cholesterol efflux to inhibit foam cell formation. In an APOE−/− mouse model, Col@HMnO2-MM significantly reduced inflammatory factor levels, lipid storage, and plaque formation without significant long-term toxicity. In summary, this synergistic treatment significantly improved the effectiveness of nanomedicine and may offer a novel strategy for precise AS therapy. [ABSTRACT FROM AUTHOR]

Ferroptosis has emerged as a promising strategy for cancer treatment. Nevertheless, the efficiency of ferroptosis-mediated therapy remains a challenge due to high glutathione (GSH) levels and insufficient endogenous hydrogen peroxide in the tumor microenvironment. Herein, we presented a nitric-oxide (NO) boost-GSH depletion strategy for enhanced ferroptosis therapy through a multifunctional nanoplatform with near-infrared (NIR) triggered NO release. The nanoplatform, IS@ATF, was designed that self-assembled by loading the NO donor L-arginine (L-Arg), ferroptosis inducer sorafenib (SRF), and indocyanine green (ICG) onto tannic acid (TA)-Fe3+‒metal-phenolic networks (MPNs) modified with hydroxyethyl starch. Inside the tumor, SRF could inhibit GSH biosynthesis, impair the activation of glutathione peroxidase 4, and disrupt the ferroptosis defensive system. In conjunction with TA-Fe3+‒MPNs, which has cascaded Fenton catalytic activity, it could navigate the lethal ferroptosis to cancer cells. Upon NIR laser irradiation, the ICG-generated ROS oxidated L-Arg to a substantial quantity of NO, which further depleted the intracellular GSH and caused LPO accumulation, enhancing cell ferroptosis. Moreover, ICG also serves as a photothermal agent that can produce hyperthermia when exposed to irradiation, further potentiating ferroptosis therapy. In addition, the nanoplatform showed significantly improved tumor therapeutic efficacy and anti-metastasis efficiency. This work thus demonstrated that utilizing NO boost-GSH depletion to enhance ferroptosis induction is a feasible and promising strategy for cancer treatment. [ABSTRACT FROM AUTHOR]

The productions of hydrogen peroxide (H2O2) and hydrogen (H2) in a photoelectrochemical (PEC) water splitting cell suffer from an onset potential that limits solar conversion efficiencies. Moreover, the formation of H2O2 through two‐electron PEC water oxidation reaction competes with four‐electron oxidation evolution reaction. Herein, we developed the surface selenium doped antimony trisulfide photoelectrode with the integrated ruthenium cocatalyst (Ru/Sb2(S,Se)3) to achieve the low onset potential and high Faraday efficiency (FE) for selective H2O2 production. The photoanode exhibits an outstanding average FE of 85 % in the potential range of 0.4–1.6 VRHE and the H2O2 yield of 1.01 μmol cm−2 min−1 at 1.6 VRHE, especially at low potentials of 0.1–0.55 VRHE with 80.4 % FE. Impressively, an unassisted PEC system that employs light and electrolyte was constructed to simultaneously produce H2O2 and H2 production on both the Ru/Sb2(S,Se)3 photoanode and the Pt/TiO2/Sb2S3 photocathode. The integrated system enables the average PEC H2O2 production rate of 0.637 μmol cm−2 min−1 without applying any addition bias. To our knowledge, this is the first demonstration that Sb2S3‐based photoelectrodes exhibit H2O2/H2 two‐side production with a strict key factor of the system, which represents its powerful platform to achieve high efficiency and productivity and the feasibility to facilitate value‐added products in neutral conditions. [ABSTRACT FROM AUTHOR]