Search Results (4,451)

As cold-sensitive fruits, loquats easily develop chilling injury (CI) during cold storage, which leads to quality deterioration and economic losses. Our prior research indicated that exogenous melatonin (MT) treatment can mitigate CI in postharvest loquats by regulating reactive oxygen species (ROS) metabolism, but the underlying molecular mechanism remains unclear. The primary objective of this study is to decipher the molecular regulatory pathway by which MT alleviates CI in postharvest loquats, focusing on the role of MYB transcription factors (TFs) in modulating antioxidant enzyme genes. Here, MT treatment remarkably reduced CI severity in loquat fruits, as reflected by lower CI index, reduced cell membrane permeability, decreased firmness, lower a* and b* values, and higher L* value, compared with the control group. Moreover, a cold-induced MYB TF, designated EjMYB15, was identified. Compared to non-treated fruits, the expression level of EjMYB15 was maintained at higher levels in MT-treated loquats. Subcellular localization and transactivation assays demonstrated that EjMYB15 is a nuclear-localized transcriptional activator. Electrophoretic mobility shift assay (EMSA) and dual-luciferase reporter (DLR) assays showed that EjMYB15 binds the MYB-binding sites (MBS) in the promoters of four antioxidant enzyme genes (EjCAT1, EjCAT2, EjGST1, and EjGST2), thereby activating their transcription. Taken together, these findings indicate that EjMYB15 positively regulates cold tolerance of loquat fruits by improving ROS scavenging capacity. These results elucidate the regulatory pathway by which MYB TFs mitigate CI and provide new theoretical support for the application of MT in alleviating CI in postharvest fruits. Full article

As a natural flavonoid compound, quercetin possesses excellent antioxidant, anti-inflammatory and anti-atherosclerotic activities. However, the poor water solubility and sensitivity to the environment severely limit the application of quercetin. Initially, quercetin-loaded zein/carboxymethyl chitosan nanoparticles (ZCQ NPs) were prepared using an anti-solvent precipitation method. The fabricated ZCQ NPs exhibited a small particle size and polydispersity index (PDI). The ZCQ NPs had a negative zeta potential with an absolute value of 41.50 ± 1.76 mV. ZCQ NPs could remain highly stable against light, heat and ion strength. In addition, ZCQ NPs maintained good monodispersity and displayed minimal changes in particle size under long-term storage conditions. Additionally, a superior antioxidant capacity of ZCQ NPs was also observed in the free radical and reactive oxygen species (ROS) scavenging study compared to that of free quercetin. All these results of this study suggest that ZCQ NPs could serve as an effective drug delivery system for encapsulating and delivering quercetin. Full article

Listeria monocytogenes (LM) contamination constitutes a paramount global threat to food safety, necessitating the urgent development of advanced, rapid, and non-destructive detection methodologies to ensure food security. This study successfully synthesized Bi₂WO₆ nanoflowers through optimized feed ratios of raw materials and further functionalized them with noble metal Au to construct a high-performance Au-Bi₂WO₆ composite nanomaterial. The composite exhibited high sensing performance toward acetoin, including high sensitivity (R_a/R_g = 36.9@50 ppm), rapid response–recovery kinetics (13/12 s), and excellent selectivity. Through UV-Vis diffuse reflectance spectroscopy (UV-Vis DRS) and X-ray photoelectron spectroscopy (XPS) characterizations, efficient electron exchange between Au and Bi₂WO₆ was confirmed. This electron exchange increased the initial resistance of the material, effectively enhancing the response value toward the target gas. Furthermore, the chemical sensitization effect of Au significantly increased the surface-active oxygen content, promoted gas–solid interfacial reactions, and improved the adsorption capacity for target gases. Compared to conventional turbidimetry, the Au-Bi₂WO₆ nanoflower-based gas sensor demonstrates superior practical potential, offering a novel technological approach for non-destructive and rapid detection of foodborne pathogens. Full article

The field of electrochemical devices, encompassing energy storage, fuel cells, electrolysis, and sensing, is fundamentally reliant on the electrode materials that govern their performance, efficiency, and sustainability. Traditional materials, while foundational, often face limitations such as restricted reaction kinetics, structural deterioration, and dependence on costly or scarce elements, driving the need for continuous innovation. Emerging electrode materials are designed to overcome these challenges by delivering enhanced reaction activity, superior mechanical robustness, accelerated ion diffusion kinetics, and improved economic feasibility. In energy storage, for example, the shift from conventional graphite in lithium-ion batteries has led to the exploration of silicon-based anodes, offering a theoretical capacity more than tenfold higher despite the challenge of massive volume expansion, which is being mitigated through nanostructuring and carbon composites. Simultaneously, the rise of sodium-ion batteries, appealing due to sodium’s abundance, necessitates materials like hard carbon for the anode, as sodium’s larger ionic radius prevents efficient intercalation into graphite. In electrocatalysis, the high cost of platinum in fuel cells is being addressed by developing Platinum-Group-Metal-free (PGM-free) catalysts like metal–nitrogen–carbon (M-N-C) materials for the oxygen reduction reaction (ORR). Similarly, for the oxygen evolution reaction (OER) in water electrolysis, cost-effective alternatives such as nickel–iron hydroxides are replacing iridium and ruthenium oxides in alkaline environments. Furthermore, advancements in materials architecture, such as MXenes—two-dimensional transition metal carbides with metallic conductivity and high volumetric capacitance—and Single-Atom Catalysts (SACs)—which maximize metal utilization—are paving the way for significantly improved supercapacitor and catalytic performance. While significant progress has been made, challenges related to fundamental understanding, long-term stability, and the scalability of lab-based synthesis methods remain paramount for widespread commercial deployment. The future trajectory involves rational design leveraging advanced characterization, computational modeling, and machine learning to achieve holistic, system-level optimization for sustainable, next-generation electrochemical devices. Full article

Nitrite pollution in aquatic environments, often driven by human activity, can disrupt fish physiology. Nitrite is absorbed by freshwater fish through their gills, leading to internal accumulation and interference with nitric oxide (NO) signaling, redox state, and the oxygen-carrying capacity of blood. The effects of nitrite are concentration-dependent. Although moderate environmental nitrite levels have little impact on oxygen transport, they may still interfere with NO homeostasis and cellular metabolism. We report the effects of 72 h of exposure to 10 μM nitrite on adult zebrafish blood’s O₂-carrying capacity and on muscle mitochondrial activity, metabolism, and redox state. The results show that this environmentally relevant but moderate concentration of nitrite leads to decreases in fish routine oxygen consumption (rMO₂) and spontaneous activity, an increase in blood nitrosyl hemoglobin (HbNO), indicating increased NO production in the blood, accumulation of nitrite in muscle tissue, oxidative stress, and changes in muscle aerobic capacity linked to a rise in mitochondrial efficiency. Parallel to these effects, increases in antioxidant capacity, arginase activity, and urea and lactate levels were observed. Globally, these results are consistent with altered NO homeostasis in the fish body induced by nitrite stress. Full article

Ultraviolet B radiation is a major cause of skin aging, cellular senescence, and inflammaging, mediated by the excessive production of reactive oxygen species (ROS) and induction of apoptosis. This study evaluated the photo-protective effects of astaxanthin, one of the strongest natural antioxidants, in UVB-treated keratinocytes. The antioxidant capacity of astaxanthin was evaluated using ABTS, DPPH, and NBT/riboflavin/SOD assays. HaCaT cells were exposed to 30 mJ/cm² of UVB radiation. Photoprotective effects and accumulated ROS were evaluated in UVB-irradiated HaCaT cells by MTT and DCFH-DA assays. Nitric oxide levels were quantified using the Griess reagent. Apoptosis was assessed by dual staining using acridine orange/ethidium bromide, lysosomal integrity by acridine orange uptake, and cell migration by scratch assay. Cell adhesion was assessed on ECM-coated Nunc plates. Finally, we formulated a 0.5% astaxanthin-enriched cream. Astaxanthin mitigated UVB-induced damage by reducing intracellular ROS levels by 3.7-fold, decreasing nitric oxide production to 29.8 ± 7.7% at the highest concentration, and maintaining lysosomal integrity. The carotenoid significantly enhanced cell viability, increasing it from 60.64 ± 8.3% in UV-treated cells to 102.1 ± 3.22% at 40 µM. Moreover, treated cells showed a significant reduction (p < 0.001) in the apoptotic rate (37.7 ± 3.1 vs. 87.7 ± 3.8 in UVB-irradiated cells, as evidenced by reduced chromatin condensation and nuclear fragmentation. Astaxanthin also enhanced tissue repair, as evidenced by increased cell migration and adhesion to several extracellular matrix (ECM) proteins (poly-L-lysine, laminin, fibrinogen, vitronectin and collagen I). In silico molecular docking predicted strong binding affinities between astaxanthin and key cellular targets, including JAK2 (−9.9 kcal/mol, highest affinity), STAT3, FAK, COX-2, NF-k-B, MMP2, and MMP9. The formulated cream demonstrated an in vitro SPF of 7.2 ± 2.5. Astaxanthin acts as a multifunctional photoprotective compound, providing a strong rationale for its incorporation into cosmetic and dermatological formulations, as further supported by the successful formulation and in vitro SPF estimation of an astaxanthin-enriched cream. Full article

Traditional bioretention systems have limited nitrogen and phosphorus removal capacity and insufficient operational stability. To address this issue, this study developed an iron-carbon bioretention system (IB) with varying submerged zone heights. The system’s performance in removing pollutants was systematically evaluated under different rainfall intensities, influent pollutant concentrations, and antecedent drying durations. In addition, the potential nitrification ability (PNA) of the substrate, denitrifying enzyme activity (DEA), and phosphorus species were analyzed to reveal the mechanisms responsible for its efficient nitrogen and phosphorus removal. The results showed that a submerged zone height of 400 mm enabled the IB system to achieve removal rates of 98.05% for ${\displaystyle {\mathrm{NO}}_3^{-}}$-N and 91.67% for total nitrogen (TN). The removal rates of total phosphorus (TP) and chemical oxygen demand (COD) remained stable at over 91% and 92%, respectively. The submerged zone also created a stable anoxic environment, while the iron-carbon micro-electrolysis process continually consumed dissolved oxygen and provided Fe²⁺ as an electron donor, enhancing both the denitrification process and chemical phosphorus removal. Furthermore, the IB system demonstrated superior stability when dealing with high hydraulic and pollutant loads, as well as varying dry periods, with the effluent iron concentration maintained at low levels. This study confirms that iron-carbon micro-electrolysis and the incorporation of a submerged zone can significantly enhance the removal performance of bioretention systems, offering a reference for addressing nitrogen and phosphorus pollution in urban stormwater runoff. Full article

Spontaneous coal combustion accounts for more than 90% of mine fires, and at the same time, the ‘dual carbon’ strategy requires fire prevention and extinguishing materials to have both low-carbon and environmentally friendly functions. To meet on-site application needs, a composite gel with fast injection, flame retardant, and CO₂ adsorption functions was developed. PVA-PEI-PAC materials were selected as the gel raw materials, and an orthogonal test with three factors and three levels was used to optimize the gelation time parameters to identify the optimal formulation. The microstructure of the gel, CO₂ adsorption performance, as well as its inhibition rate of CO, a marker gas of coal spontaneous combustion, and its effect on activation energy were systematically characterized through SEM, isothermal/temperature-programmed/cyclic adsorption experiments, and temperature-programmed gas chromatography. The results show that the optimal gel formulation is 14% PVA, 7% PEI, and 5.5% PAC. The gel microstructure is continuous, dense, and rich in pores, with a CO₂ adsorption capacity at 30 °C and atmospheric pressure of 0.86 cm³/g, maintaining over 76% efficiency after five cycles. Compared with raw coal, a 10% gel addition reduces CO release at 170 °C by 25.97%, and the temperature-programmed experiment shows an average CO inhibition rate of 25% throughout, with apparent activation energy increased by 14.96%. The gel prepared exhibited controllable gelation time, can deeply encapsulate coal, and can efficiently adsorb CO₂, significantly raising the coal–oxygen reaction energy barrier, providing an integrated technical solution for mine fire prevention and extinguishing with both safety and carbon reduction functions. Full article

Oxidation can lead to intrinsic degradation and loss in the load-bearing capacity of ceramic matrix composites (CMCs) in high-temperature service, thereby compromising structural integrity and operational safety. To elucidate the mechanism of its oxidation effects, this study predicted the oxygen diffusion coefficient within 2.5D woven C/SiC fibre bundles based on gas diffusion and oxidation kinetics theory, and subsequently constructed a meso-scale constitutive model incorporating oxidation damage and fibre defect distribution. Furthermore, a micro-scale framework for yarns was established by integrating interfacial slip behaviour, and an RVE model for 2.5D woven C/SiC was constructed based on X-ray computed tomography reconstruction of the actual microstructure. Building upon this foundation, an oxidation constitutive model applicable to loading–unloading cycles was proposed and validated through high-temperature oxidation tests at 700 °C, 900 °C, and 1100 °C. Results demonstrate that this model effectively characterizes the strength degradation and stiffness reduction caused by oxidation, enabling prediction of CMCs’ mechanical properties under oxidizing conditions and providing a physics-based foundation for the reliable design and life assessment of C/SiC components operating in oxidizing environments. Full article

Background: Stage B heart failure (SBHF) increases the risk of symptomatic HF. Current guideline criteria for SBHF lack sex and ethnic thresholding and cardiac magnetic resonance (CMR) imaging cut-offs. We aimed to assess the prevalence of SBHF in a large cohort of people with type 2 diabetes (T2D) and healthy controls and propose a refined CMR definition for SBHF. Methods: Sex- and ethnic-specific thresholds for imaging criteria were derived from 373 healthy controls, who underwent CMR cine imaging. The current definition for SBHF and refined criteria was applied to our prospectively recruited and intensively phenotyped cohort of asymptomatic people with T2D and no evidence of cardiovascular disease. The prevalence of SBHF by different definitions was calculated and patient characteristics, including exercise capacity, were compared between those classified as Stage A vs. B HF. Finally, the refined criteria were also applied to the following two historical cohorts with symptomatic cardiovascular disease: severe aortic stenosis (AS n = 70) and HF with preserved ejection fraction (HFpEF n = 136). Results: A total of 423 people with T2D and a subset of 102 healthy controls who underwent echocardiography were prospectively recruited. Current guideline criteria classified 91% of those with T2D and 69% of the healthy controls as SBHF, suggesting a lack of specificity. Applying derived sex- and ethnicity-specific thresholds, combining echo and CMR measures, the prevalence of SBHF was reduced to 30% in those with T2D. Using the refined definition, those with Stage B HF had lower exercise capacity than those with Stage A HF (percentage predicted maximal oxygen consumption 81 ± 16% vs. 91 ± 20%, p < 0.001). Applying the refined definition to symptomatic AS and HFpEF participants classified 89% and 85% with abnormal cardiac remodelling. Conclusion: Current guideline criteria for SBHF are non-specific and likely of limited value in clinical practice. Refining these criteria with sex- and ethnic-specific thresholds may improve identification of those at risk of developing symptomatic disease. Further research is required to validate these criteria. Full article

The appeal of chitosan (CS) stems not only from its exceptional char-forming capacity and molecular tailorability as a flame retardant, but also from its intrinsic thermal responsiveness as a potential fire warning, making it a building block of advanced materials for fire management. Herein, this review provides an up-to-date exploration of advancements in CS and its derivative-based multi-functional composites, with a particular focus on the flame-resistant and fire-warning applications. Specifically, these summaries involve various manufactory approaches, the customed flame-retardant regulation (reflected in a higher Limiting Oxygen Index (LOI) value, a V-0 rating, and a decreased peak of heat release rate (pHRR)), a corresponding principle of flame retardancy, different fire-warning modulations (lower warning temperatures and shorter response times), an underlying fire-warning mechanism (electrical current change), and challenges and opportunities for further development (the assistance of artificial intelligence (AI), multi-functional integration). We mainly aim to present a comprehensive overview that can offer strong guidance for the construction of a new generation of advanced CS-based materials. Full article

This manuscript reports the preparation, surface characterization, and modeling of chars and activated carbons obtained from avocado biomass for hydrogen storage. Activated carbons were prepared from avocado biomass via the following stages: (a) pyrolysis of avocado biomass, (b) impregnation of the avocado-based char using an aqueous lithium solution, and (c) thermal activation of lithium-loaded avocado char. The synthesis conditions of char and activated carbon samples were tailored to maximize their hydrogen adsorption properties at 77 K, where the impact of both pyrolysis and activation conditions was assessed. The hydrogen storage mechanism was discussed based on computational chemistry calculations and multilayer adsorption simulation. The modelling focuses on the analysis of the saturation of activated carbon active sites via the adsorption of multiple hydrogen molecules. The results showed that the activated carbon samples displayed adsorption capacities higher than their char counterparts by 71–91% because of the proposed activation protocol. The best activated carbon obtained from avocado residues showed a maximum hydrogen adsorption capacity of 142 cm³/g, and its storage performance can compete with other carbonaceous adsorbents reported in the literature. The hydrogen adsorption mechanism implied the formation of 2–4 layers on activated carbon surface, where physical interactions via oxygenated functionalities played a relevant role in the binding of hydrogen dimers and trimers. The results of this study contribute to the application of low-cost activated carbons from residual biomass as a storage medium in the green hydrogen supply chain. Full article

Seasonal fluctuations in the chemical composition of fine particulate matter (PM_2.5) are known to influence its toxicological properties; however, their integrated biological effects remain incompletely understood. In this study, PM_2.5 was continuously collected over two consecutive years at a single urban site in Japan and classified by season. The samples were comprehensively characterized for ionic species, metals, carbonaceous fractions, and polycyclic aromatic hydrocarbons (PAHs), and their pulmonary effects were evaluated in vivo following intratracheal administration in mice. Seasonal PM_2.5 exhibited pronounced compositional differences, with higher levels of secondary inorganic aerosol components in summer and enrichment of PAHs and mineral-associated components in winter. These seasonal differences translated into distinct biological responses. Reactive oxygen species (ROS) production (1.6–2.7-fold increase) and bronchoalveolar lavage (BAL) neutrophil infiltration were strongly associated with PAH-rich PM_2.5, whereas interleukin-1α (IL-1α) showed robust positive correlations with mineral components, including K⁺, Ca²⁺, and Mg²⁺, which were predominantly enriched in winter PM_2.5. In contrast, secondary inorganic aerosol species displayed a limited capacity to induce IL-1α. Compared with summer samples, winter PM_2.5 induced significantly higher levels of ROS production and IL-1α (approximately 1.5–2.6-fold increase). Using TLR2- and TLR4-deficient mice, we further demonstrated that PM_2.5-induced increases in BAL cell counts, ROS, IL-6, and TNF-α were partially attenuated in TLR4 knockout mice, indicating a contributory but not exclusive role for TLR4 signaling in PM_2.5-driven pulmonary inflammation. Collectively, these findings demonstrate that seasonal variations in PM_2.5 composition, not particle mass alone, critically shape oxidative stress and innate immune responses in the lungs. In particular, winter PM_2.5 enriched in mineral-associated components preferentially activates IL-1α-mediated alarmin pathways, underscoring the importance of the particle composition in determining seasonal air pollution toxicity. Full article

The sustainable management of sewage sludge remains a key environmental challenge for rapidly urbanizing regions such as Kazakhstan. This study explores the potential of sewage sludge-derived biochar as an efficient, low-cost adsorbent for removing Rhodamine B (RhB) dye and toxic metals from water. Sewage sludge was pyrolyzed at 700 °C (BC) and subsequently activated with hydrochloric acid (BCH) and sodium hydroxide (BCN) to improve its surface functionality and porosity. The morphology, surface area, porosity, and functional groups of the obtained biochars were characterized using SEM-EDS, BET, FTIR, and XRD analyses. Batch adsorption experiments demonstrated that the pseudo-second-order kinetic model (R² = 0.99) best described the data, indicating chemisorption-controlled uptake. Experimental RhB adsorption capacity was 14.53 mg/g for BCH at RhB concentration of 75 mg/L after 120 min. Moreover, BCH exhibited enhanced metal adsorption capacities of 22.85 mg/g (Cu²⁺), 17.55 mg/g (Zn²⁺), 15.08 mg/g (Cd²⁺), 7.97 mg/g (Cr³⁺), and 3.68 mg/g (As³⁺). These results confirm that acid activation significantly improves adsorption efficiency compared with pristine biochar due to increased surface area and the introduction of oxygen-containing functional groups. Overall, sewage sludge-derived biochar shows strong potential as a sustainable adsorbent for dye and heavy metal removal. Full article

Microorganisms have emerged as prolific and versatile producers of steroidal natural products, displaying a remarkable capacity for structural diversification that extends far beyond classical sterol frameworks. This review critically examines steroidal metabolites isolated from microbial sources, with a particular emphasis on marine-derived and endophytic fungi belonging to the genera Aspergillus and Penicillium, alongside selected bacterial and lesser-studied fungal taxa. Comparative analysis reveals that these organisms repeatedly generate distinctive steroid scaffolds, including highly oxygenated ergostanes, secosteroids, rearranged polycyclic systems, and hybrid architectures arising from oxidative cleavage, cyclization, and Diels–Alder-type transformations. While many reported compounds exhibit cytotoxic, anti-inflammatory, antimicrobial, or enzyme-inhibitory activities, the biological relevance of these metabolites varies considerably, highlighting the need to distinguish broadly recurring bioactivities from isolated or strain-specific observations. By integrating structural classification with biosynthetic considerations and bioactivity trends, this review identifies key steroidal frameworks that recur across taxa and appear particularly promising for further pharmacological investigation. In addition, current gaps in mechanistic understanding and compound prioritization are discussed. Finally, emerging strategies such as genome mining, biosynthetic gene cluster analysis, co-culture approaches, and synthetic biology are highlighted as powerful tools to unlock the largely untapped potential of microbial genomes for the discovery of novel steroidal scaffolds. Together, this synthesis underscores the importance of microorganisms as a dynamic and expandable source of structurally unique and biologically relevant steroids, and provides a framework to guide future discovery-driven and mechanism-oriented research in the field. Full article