Search Results (1,812)

Styrene chlorohydrin is an important intermediate used in the manufacturing of high-value specialty chemicals. This paper focuses on understanding the kinetic aspects of styrene chlorohydrin production using hydrogen peroxide and hydrochloric acid. For this two-phase non-catalytic system, lab-scale initial rate experiments are conducted to assess the impact of key design parameters, such as reaction temperature, speed of agitation, and phase volume fraction, on the observed reaction rate. Based on these studies, it has been shown that this reaction takes place in the aqueous phase and the apparent order of reaction with respect to styrene, hydrogen peroxide and hydrochloric acid is approximately one, one and two, respectively. The corresponding Hatta number values are much smaller than one and the enhancement factor is approximately one, confirming that the system operates in regime I. Subsequently, a detailed reaction mechanism is proposed to capture the composition profiles of styrene chlorohydrin as well as the other major side products. The proposed model is then validated against composition trends observed in full-batch experiments. The model captured concentration profiles accurately, yielding sum of squared error (SSE) values around three. This model can be utilized to design and optimize the commercial manufacturing process for styrene chlorohydrin. Full article

Low-cost, efficient, and durable electrocatalysts for two-electron oxygen reduction (2e⁻ ORR) to synthesize hydrogen peroxide (H₂O₂) are essential for sustainable chemical manufacturing. Herein, we report a sustainable route to prepare activated carbon electrodes (ASC) from municipal sludge via chemical activation and pyrolysis. The electrode activated with 30 wt.% H₃PO₄ and calcined at 600 °C for 2 h exhibited high catalytic activity. This electrode featured a hierarchical micro-/meso-/macroporous structure with a high BET surface area of 806.20 m²·g⁻¹, abundant carboxyl groups (surface O content of 4.0 at.%), and high hydrophobicity (contact angle of 121.6°). The unique hierarchical porosity, high surface area, hydrophobic surface, and carboxyl functionalities synergistically enhanced O₂ mass transfer, exposed abundant accessible active sites, and stabilized the triple-phase interface. Electrochemical evaluation revealed that 30 wt.% H₃PO₄-ASC achieved a high H₂O₂ selectivity of 86–92% with an electron transfer number of 2.2, approaching the ideal 2e⁻ ORR pathway. Under optimized conditions (pH = 3, j = 5.0 mA·cm⁻²), it produced 997.3 mg·L⁻¹ of H₂O₂ in 90 min, with a current efficiency of 68.8% and an energy consumption of 27.6 kWh·kg⁻¹ H₂O₂. Moreover, the electrode retained 81.1% of its initial H₂O₂ production after 15 cycles, demonstrating good reusability and long-term stability. This work offers a sustainable strategy for high-value utilization of municipal sludge and advances the development of efficient electrocatalysts for green H₂O₂ production. Full article

Soil salinity severely limits grapevine (Vitis spp.) growth and productivity, yet the mechanisms distinguishing tolerant and sensitive rootstocks remain incompletely understood. We compared the salt-tolerant rootstock ‘SO4’ with the salt-sensitive ‘Beida’ under 100 mmol L⁻¹ NaCl for 0, 6, and 12 days. Salinity progressively reduced photosynthetic pigments in both genotypes, although ‘SO4’ retained higher levels. Salt treatment also increased hydrogen peroxide, malondialdehyde, soluble sugars, soluble proteins, proline, and antioxidant enzyme activities. Compared with ‘Beida’, ‘SO4’ showed stronger osmotic adjustment and greater activation of superoxide dismutase, peroxidase, catalase, and ascorbate peroxidase. RNA-seq analysis revealed extensive genotype- and time-dependent transcriptional reprogramming, with differentially expressed genes mainly associated with hormone signalling, secondary metabolism, carbon fixation, protein processing, and lipid metabolism. Weighted gene co-expression network analysis identified the MEblack module as positively associated with salt tolerance in ‘SO4’ but negatively associated with ‘Beida’. Within this module, Vitvi01g00735/VvBCA2 and Vitvi07g02043/VvLCB1 were prioritized as candidate hubs based on high module membership, gene significance, and intramodular connectivity. Hub-centred networks linked VvBCA2 to redox regulation, protein homeostasis, defense, and osmotic signalling, whereas VvLCB1 was associated with cell-wall remodelling, methyl metabolism, membrane signalling, and lipid turnover. Transcription-factor families, including MYB, WRKY, AP2/ERF, bHLH, and HSF, were more strongly represented in ‘SO4’. Collectively, these findings identify coordinated physiological and transcriptional mechanisms underlying salt tolerance and provide candidate genes for grapevine improvement. Full article

Selenium (Se) is a beneficial element that enhances plant antioxidant capacity, improves fruit quality, and contributes to the biofortification of horticultural crops. However, information regarding its effects on mineral nutrient balance and antioxidant metabolism in pomegranate remains limited. This study investigated the effects of foliar selenium (Se) application on fruit yield, mineral nutrient balance, antioxidant metabolism, and fruit quality of pomegranate (Punica granatum L.) cv. ‘Malas Saveh’ during the 2022 and 2023 growing seasons under orchard conditions in Iran. Trees were treated with sodium selenate at different concentrations using a randomized complete block design. In 2022, Se was applied at 0, 2, 4, and 6 mg L⁻¹, while in 2023, based on the results of the first-year screening phase, the concentration range was expanded to 0, 6, 8, and 10 mg L⁻¹ to further investigate plant responses to higher Se levels. Foliar Se application significantly increased fruit yield, fruit number, and Se accumulation in both leaves and fruits, confirming the effectiveness of Se biofortification. Selenium treatments also improved the nutritional composition of pomegranate fruits by increasing the concentrations of nitrogen (N), phosphorus (P), potassium (K), iron (Fe), and zinc (Zn), whereas manganese (Mn) concentrations declined, suggesting an antagonistic interaction between Se and Mn uptake. Significant improvements were observed in fruit quality traits, including soluble solids content, titratable acidity, vitamin C, total phenolics, anthocyanins, and antioxidant activity. The 6 mg L⁻¹ treatment in 2022 and the 8–10 mg L⁻¹ treatments in 2023 resulted in the most pronounced physiological and biochemical responses, with 10 mg L⁻¹ showing no further significant improvement for several key traits. Selenium application also enhanced the antioxidant defense system through increased activities of catalase (CAT), superoxide dismutase (SOD), peroxidase (POD), phenylalanine ammonia-lyase (PAL), and ascorbate peroxidase (APX), while reducing hydrogen peroxide (H₂O₂), malondialdehyde (MDA), and membrane ion leakage. Principal component analysis further confirmed the strong positive association between higher Se concentrations and improved mineral and biochemical characteristics. Overall, foliar Se application effectively enhanced pomegranate productivity, nutritional quality, antioxidant capacity, and physiological performance, highlighting its potential as a sustainable agronomic practice for the production of high-quality Se-enriched fruits. Full article

Heavy metal stress severely impairs global agricultural productivity, a challenge exacerbated by rising industrial activities. To mitigate chromium (Cr) toxicity in crops, this study evaluated the potential of seed priming with four distinct acids, ascorbic acid (AA), citric acid (CA), nitric acid (NA), and salicylic acid (SA), on broad bean (Vicia faba L.) seedlings exposed to 50 ppm Cr(VI). Cr(VI) exposure alone severely compromised development, reducing root and shoot fresh biomass by 47% and 52.3% and lengths by 60.8% and 62.19%, respectively. This growth inhibition was mirrored by a massive drop in total soluble sugars (over twofold in shoots and threefold in roots) and a twofold spike in toxic hydrogen peroxide (H₂O₂) accumulation. However, acidic priming agents effectively protected the seedlings from this oxidative crisis. The co-application of these effectors limited the inhibitory effects of Cr(VI), increasing biomass up to twofold and reducing H₂O₂ levels by around 32% in roots and 26% in shoots. This reduction in oxidative damage subsequently alleviated cellular stress, restoring protein content (by up to 70.72% in shoots under AA) and bringing catalase (CAT) and ascorbate peroxidase (APX) activities back toward baseline levels, reducing them by more than 50% compared to the unprimed Cr(VI) control. Notably, regarding bioaccumulation, only AA priming significantly limited heavy metal uptake, reducing chromium accumulation by 36.5% in roots and 26.5% in shoots. This unique protection is likely linked to a potential chemical reduction of mobile Cr(VI) near the root boundaries and the regulation of internal osmoprotectant systems. These findings suggest that seed priming with these effectors, especially AA, offers a highly scalable, low-cost, and sustainable strategy for enhancing crop tolerance in heavy-metal-polluted soils. Full article

Objective: This study investigated the effects of three chronic stress exposure models (permanent elimination, forced swimming, and food and water deprivation) on bone oxidative stress, structure, and metabolism in vivo. Methods: Adult rats were exposed to different stress conditions, while control animals were maintained under standard laboratory conditions. Bone morphological and histological parameters, oxidative stress biomarkers, antioxidant defense system, and mineral concentrations were assessed. Results: Stress exposure resulted in significant reductions in body weight, femur weight, and femur length compared to controls. A marked increase in oxidative stress biomarkers was observed in bone tissue, including lipid peroxidation, reactive oxygen species, hydroperoxides, hydrogen peroxide, protein carbonyls, and advanced oxidation protein products. In contrast, antioxidant defenses, including enzymatic activities and levels of glutathione, non-protein thiols, and vitamin C, was significantly decreased. Bone calcium and phosphorus levels were reduced, whereas their plasma concentrations were increased following stress exposure. Histological analysis confirmed the biochemical alterations, suggesting that chronic stress can disrupt bone integrity via oxidative mechanisms. Conclusions: These findings highlight the need for strategies to control and reduce stress-related disorders to maintain skeletal health under various chronic stress conditions. Full article

Dry age-related macular degeneration (AMD) can progress to wet AMD when leaking capillaries grow under the macula. Although rare, this transition holds significant risk as it causes more rapid and severe vision loss. Oxidative stress is damaging to cellular components and plays a pivotal role in chronic diseases. We aim to determine whether oxidative stress in retinal pigment epithelial (RPE) cells elicits a proangiogenic microenvironment. We exposed human primary RPE cells to hydrogen peroxide (H₂O₂), and we analyzed their metabolic activity, and the production of reactive oxygen species (ROS) and angiogenic factors. In addition, we evaluated the potential of RPE cell-conditioned medium (CM) to induce HUVEC cell tube formation. RPE cells exposed to H₂O₂ displayed a dose-dependent decrease in their metabolic activity, and increased ROS levels. The analysis of the CM of exposed RPE cells revealed differential expression of a panel of proangiogenic factors. Notably, the expression of the major angiogenic factors (VEGF, FGF) was increased. Exposure of HUVEC cells to the CM of H₂O₂-exposed RPE cells promoted tube formation suggestive of microvessel formation. Our findings bring new insights into the role of oxidative stress in altering RPE cell behavior that might have consequences in the progression of AMD towards the exudative form. Full article

Molybdenum-doped xerogel composites were prepared and applied in the electro-degradation of tetracycline (TTC), an antibiotic commonly prescribed for the treatment of bacterial infections. Xerogels containing 1, 6, and 14 wt% Mo were synthesized using an RF sol–gel polymerization method in cylindrical molds and were subsequently characterized in terms of their textural, chemical, and electrochemical properties, focusing on the oxygen reduction reaction (ORR). Textural characterization revealed well-developed surface areas and mesoporosity. Electrochemical analysis showed that Mo loading plays a vital role in the ORR mechanism: lower metal content favors the four-electron pathway with lower hydrogen peroxide selectivity, whereas higher Mo loadings promote bifunctional behavior, enabling both in situ H₂O₂ generation and hydroxyl radical production. Undoped and doped xerogels were very active for TTC degradation via the electro-Fenton process, but the presence of MoO₃ and Mo₂C phases improved up to 12% in removal efficiency after 480 min of treatment. Full article

Root-knot nematodes (RKNs; Meloidogyne spp.) are among the most destructive plant parasites, causing severe yield losses in diverse crops. Reactive oxygen species (ROS), particularly superoxide radicals (O₂•⁻) and hydrogen peroxide (H₂O₂), are central regulators of plant–RKN interactions. This review synthesizes current molecular, biochemical, genetic, transcriptomic, and translational evidence showing that the outcome of infection is determined by the spatiotemporal regulation of H₂O₂ rather than by ROS abundance alone. In resistant interactions, nematode perception activates PTI-associated signaling through selected cell-surface receptor complexes, including some BAK1/SERK3-associated pathways, together with BIK1, Ca²⁺ signaling, and RBOHD/F, generating a sustained oxidative activity associated with salicylic acid-dependent immune signaling and reduced H₂O₂-scavenging capacity and coupled to hypersensitive response, lignin and callose deposition, and feeding site restriction. In susceptible interactions, RKNs deploy ROS-targeting effectors such as Mi-CRT, MjTTL5, CATLe, Mj-NEROSs, and CMII to suppress ROS production, enhance antioxidant scavenging, or weaken SA-dependent defense. Evidence from a cyst-nematode system suggests that RBOH-derived ROS can restrict excessive cell death around syncytia; whether an analogous lower-redox requirement exists in RKN-induced giant cells remains unresolved. Finally, redox-based strategies, including CRISPR/Cas editing, host-induced gene silencing, chemical priming, and biocontrol, are discussed as promising approaches for durable and sustainable nematode resistance. Full article

Water-soluble blue microbial pigments with antioxidant activity remain rare, and their host-level protective mechanisms are poorly understood. Here, we identified the genetic basis of blue pigment biosynthesis in the glacier-derived strain Arthrobacter antioxidans QL17. Heavy-ion mutagenesis yielded a hyperpigmented mutant (M157) and a pigment-deficient mutant (M186), and pigment yield was positively associated with hydrogen peroxide (H₂O₂) tolerance. Genome mining identified MWM45_RS16760 as the sole core biosynthetic gene in a candidate nonribosomal peptide synthetase (NRPS)-like cluster. The encoded protein displayed an adenylation–peptidyl carrier protein–thioesterase (A-PCP-TE) architecture with a predicted L-glutamine-specific A domain, and its transcript abundance paralleled pigment production across the three strains. Phylogenetic analysis placed MWM45_RS16760 in a distinct actinomycete-associated indigoidine-like lineage separated from the characterized BpsA and IndC branches. Heterologous expression in Escherichia coli reconstructed a blue-pigment-producing phenotype, increased H₂O₂ tolerance, and was accompanied by enhanced extracellular DPPH and ABTS radical-scavenging activities in the culture supernatant. Comparative transcriptomics further revealed coordinated activation of oxidative-stress and proteostasis responses alongside repression of tryptophan biosynthesis and flagellar assembly. These findings identify MWM45_RS16760 as a candidate indigoidine-like NRPS associated with blue pigment biosynthesis and oxidative-stress resistance, with heterologous expression linked to enhanced radical scavenging and coordinated transcriptional reprogramming, expanding the phylogenetic and functional diversity of indigoidine-like systems. Full article

Finger millet (Eleusine coracana L.) is rich in bioactive compounds, including flavonoids. Following exogenous substance regulation, its sprouts can achieve efficient flavonoid enrichment. This study investigates the regulatory effects of exogenous salicylic acid (SA) and γ-aminobutyric acid (GABA) on the physiological metabolism, oxidative stress response, and flavonoid biosynthesis of finger millet sprouts subjected to 5 mM zinc sulfate (ZnSO₄) stress. Compared to treatment solely with ZnSO₄, the application of both 50 μM salicylic acid (SA) and 1 mM gamma-aminobutyric acid (GABA) markedly enhanced flavonoid biosynthesis, with respective yields of 8.53 μg/sprout and 8.85 μg/sprout observed by 6 days post-germination. Concurrently, SA and GABA attenuated ZnSO₄-induced oxidative damage. During days 4 and 6 post-germination, malondialdehyde and hydrogen peroxide levels in sprouts were significantly reduced, with levels at 6 days showing a particularly notable decrease. Moreover, the catalytic activities of catalase, peroxidase, superoxide dismutase, and ascorbate peroxidase were significantly upregulated. Further analysis revealed that both treatments significantly activated the phenylpropanoid biosynthesis pathway. The activities of key rate-limiting enzymes, phenylalanine ammonia-lyase, cinnamate-4-hydroxylase, and 4-coumarate-CoA ligase, along with the expression levels of their corresponding genes, were markedly upregulated. Concurrently, the expression of genes and transcription factors, specifically myeloblastosis and NAC transcription factors, involved in regulating reactive oxygen species homeostasis also increased. These findings suggest that exogenous SA, GABA, and ZnSO₄ cotreatment can effectively enhance the accumulation of flavonoids and the nutritional quality of finger millet sprouts by bolstering antioxidant capacity and modulating the flavonoid biosynthesis pathway. This investigation establishes a theoretical framework for the production of superior, bioactive finger millet sprout ingredients. Full article

Sonoplasma treatment (SPT), which combines hydrodynamic cavitation with low-temperature plasma discharge in water, has been proposed as an advanced oxidation process for reducing biological contamination. By generating physical stressors and reactive oxygen species, including hydrogen peroxide (HP), SPT may inactivate microorganisms, but its effects on stress-resistant filamentous fungi remain insufficiently characterized. We examined two phytopathogenic fungi with contrasting pigmentation: melanized Alternaria alternata and hyaline Fusarium solani. Spore suspensions were exposed to direct and indirect SPT at 30 kHz, and viability, biomass accumulation, conidial production, allelopathic activity, and pigmentation-associated spectral responses were assessed immediately after treatment and after storage. Fungus F. solani showed greater susceptibility, with reduced colony-forming capacity and suppressed biomass production, although surviving propagules showed increased sporulation. In contrast, A. alternata maintained viable growth under the tested conditions and showed stimulation of growth-related and reproductive endpoints, together with darker colony pigmentation. These responses are consistent with pigmentation-associated tolerance to SPT-induced physical and oxidative stress, but do not establish melanin as the sole causal mechanism. SPT efficacy against filamentous fungi is therefore species-dependent and may be limited when resistant melanized taxa are present. Full article

Two-electron oxygen reduction reaction (2e⁻-ORR) represents a sustainable and energy-efficient approach for decentralized hydrogen peroxide (H₂O₂) production compared with the conventional anthraquinone process. Among various electrocatalysts, metal–nitrogen–carbon (M–N–C) materials have attracted extensive attention owing to their tunable electronic structures and favorable *OOH adsorption behavior. However, the uncontrolled pyrolysis process generally leads to structurally heterogeneous and ill-defined coordination environments, making it difficult to precisely regulate active sites and understand catalytic mechanisms. Herein, we report a single-atom catalyst (CoN@OCNT) featuring spatially confined pyridinic-N-coordinated Co single sites, synthesized by anchoring a well-defined hexapod terpyridine Co-precursor onto oxidized carbon nanotubes (OCNTs) to suppress metal aggregation during pyrolysis. Benefiting from the optimized coordination environment and enhanced mass/electron transfer, the CoN@OCNT catalyst exhibits nearly 100% H₂O₂ selectivity over a wide potential window from −1.0 to 0.66 V versus RHE in neutral electrolyte. In situ FT-IR and Raman spectroscopy reveal a rapid *OOH-mediated reaction pathway during the 2e⁻-ORR process. Furthermore, membrane electrode assembly (MEA) testing demonstrates an H₂O₂ production rate of 21.8 mol h⁻¹ g_cat⁻¹ with stable operation over 80 h at 60 mA cm⁻². Remarkably, at an industrially relevant current density of 300 mA cm⁻², the catalyst achieves a record H₂O₂ production rate of 70.3 mol h⁻¹ g_cat⁻¹ and a salt-free H₂O₂ concentration of 9.4 mM, highlighting its great potential for practical large-scale H₂O₂ electrosynthesis in neutral media. Full article

Drought is one of the major abiotic stresses limiting soybean production, and its detrimental effects are jointly influenced by stress intensity, duration, and cultivation conditions. To investigate the morphological and physiological regulatory mechanisms by which mepiquat chloride (DPC) alleviates drought stress at the soybean seedling stage, this study used the drought-tolerant soybean cultivar Heinong 44 (H-44) and the drought-sensitive cultivar Heinong 65 (H-65) as experimental materials. Osmotic stress was simulated with 10% PEG-6000 at the V2 stage, and the effects of foliar application of different DPC concentrations (125–500 mg/L) on soybean morphology, biomass allocation, antioxidant systems, and osmotic adjustment capacity were systematically analyzed. The results showed that drought stress significantly inhibited the growth of both soybean cultivars and induced severe oxidative damage. Appropriate DPC concentrations moderately restricted shoot growth to reduce transpiration area while promoting root growth to enhance water acquisition capacity. The optimal DPC concentrations for alleviating drought stress were 200 mg/L for H-44 and 275 mg/L for H-65. Allometric growth analysis indicated that drought disrupted the original root–shoot growth pattern, whereas appropriate DPC concentrations significantly promoted dry matter accumulation in drought-stressed plants and improved root–shoot growth coordination. However, an excessive concentration of DPC (500 mg/L) caused an abnormal deviation in the growth trajectory. In addition, appropriate DPC concentrations synergistically enhanced the activities of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), and ascorbate peroxidase (APX) in leaves and roots under drought conditions; promoted the accumulation of proline (Pro), soluble sugars (Ss), and soluble proteins (Sp); effectively reduced the contents of malondialdehyde (MDA) and hydrogen peroxide (H₂O₂); and protected cell membrane stability. In conclusion, DPC synergistically enhances drought resistance in soybean by reshaping the root–shoot allometric growth configuration and systematically activating physiological defense networks, providing a theoretical basis for chemically regulated cultivation of soybean under stress conditions. Full article

Seed priming has been widely used as a strategy to improve germination and promote uniform seedling growth in horticultural crops, yet its application in microgreen production remains relatively underexplored. This study evaluated the impact of four priming treatments—hydrogen peroxide, Kelpak Maxx (a seaweed extract), Continuum^TM (a beneficial bacterial biostimulant), and hydropriming—on the germination, shoot growth, visual quality, coloration, and mineral nutrient composition of four herbal microgreen species compared with untreated raw seeds as a control treatment. Four species—chives (Allium schoenoprasum), dill (Anethum graveolens), scallion (Allium fistulosum), and shiso (Perilla frutescens)—were produced as microgreens under greenhouse conditions in two experiments in 2024 and 2025. Results revealed that early germination percentages at 3 days after treatment (DAT) in dill were increased by Kelpak Maxx, Continuum, and hydropriming by 11–18% in 2024 and by 20–40% in 2025, compared with increases for the control of 1% in 2024 and 5% in 2025. Germination percentages at 7 DAT in chives, scallion, and shiso all exceeded 88%, which were similar among priming treatments in 2024 and were not affected by priming in 2025. The four priming treatments resulted in similar fresh and dry shoot weights in chives, scallion, and shiso, but decreased fresh shoot weights in dill by 48.6% in 2024 and by 26.2% in 2025 compared with the control treatment. Species varied in mineral nutrient compositions. Priming altered concentrations of potassium, sulfur, magnesium, boron, and copper in certain species, but otherwise had minimal effects on mineral nutrient concentrations. Seed priming may potentially be used to enhance germination in slow-germinating species; however, it did not consistently improve shoot yield or mineral nutrient concentrations in the four tested microgreen species. Full article