Search Results (51,945)

Nd₂NiO_4+δ was investigated as a Ruddlesden–Popper (RP) cathode material for intermediate-temperature solid oxide fuel cells (IT-SOFCs), with particular emphasis on its electrochemical performance and oxygen reduction reaction mechanism. The material was synthesized via a polymeric sol–gel route derived from Pechini’s method and evaluated in symmetric cells using Ce_0.9Gd_0.1O_2−δ (GDC) as the electrolyte. X-ray diffraction confirmed the formation of a single RP phase and good chemical compatibility with GDC after thermal treatments at 800 °C. Cathode layers with thicknesses of 8–12 µm were deposited by dip-coating. Electrical conductivity measurements revealed a thermally activated semiconducting behavior governed by Ni²⁺/Ni³⁺ small-polaron hopping, with an activation energy of ~1.08 eV. Electrochemical impedance spectroscopy showed a strong temperature dependence of the area-specific resistance, decreasing from 9.18 Ω·cm² at 600 °C to 0.39 Ω·cm² at 800 °C. Distribution of relaxation times (DRT) analysis enabled the identification of the dominant electrochemical processes, indicating that oxygen surface exchange reactions are more favorable than charge transfer at the cathode–electrolyte interface, which remains the main limiting step. These results demonstrate that Nd₂NiO_4+δ is a promising cathode for IT-SOFC operation, while further optimization of the electrode–electrolyte interface is required to enhance its oxygen reduction kinetics. Full article

Excess post-exercise oxygen consumption (EPOC) reflects cardiorespiratory fitness, energy metabolism and the residual physiological effects of preceding exercise. We aimed to compare EPOC profiles of master swimmers across different age groups and performance levels. Fourteen male master swimmers performed a 200 m all-out front crawl and breath-by-breath gas exchange and their heart rates were recorded during exercise and for 5 min post-exercise. A single exponential regression model was fitted to the post-exercise oxygen uptake kinetics to determine the EPOC amplitude, time constant and time delay. The EPOC magnitude was calculated as the area under the oxygen uptake–time curve. Swimmers were grouped into younger vs. older and faster vs. slower clusters using the 50th percentile, and the associations between age, performance and physiological variables were examined. Older swimmers were slower and showed a lower peak oxygen uptake than their younger counterparts (213.9 ± 27.9 vs. 165.7 ± 24.9 s and 39.1 ± 4.8 vs. 50.2 ± 8.1 mL∙kg⁻¹∙min⁻¹; p < 0.05). Slower swimmers were older and displayed a lower EPOC amplitude than faster performers (69.8 ± 7.3 vs. 45.7 ± 1.7 years and 23.2 ± 4.0 vs. 36.8 ± 10.2 mL∙kg⁻¹∙min⁻¹; p < 0.05). Although many of the variables did not differ between groups, effect sizes were moderate to very large (except for time constant and time delay). The swimmers’ age related directly to their performance and inversely to their peak oxygen uptake, peak heart rate and EPOC amplitude, while performance presented inverse associations with peak oxygen uptake, peak heart rate, EPOC amplitude and EPOC magnitude (p < 0.05). Master swimmers of different ages and performance levels exhibited distinct EPOC characteristics, which may provide relevant information regarding the individualisation of training and recovery strategies in this population. Full article

This work reports a systematic study concerning the synthesis of pure polyaniline ultrafine nanofibers (PANI-NFs) and their nanocomposites with oxygen-functionalized carbon nanotubes (PANI-NFs/O-MWCNTs) using diluted chemical polymerization and hydrothermal processes. We investigated the synergistic effects of various synthesis parameters, such as the concentration of the ammonium persulfate oxidant agent and growth temperature, on the physical, chemical, and electrochemical properties of the resulting products through structural, morphological, spectroscopic, and electrochemical characterization. Our study revealed the successful synthesis of thermally resistant polyaniline ultrafine nanofibers (PANI-NFs) in the form of emeraldine salt (ES), exhibiting a mean diameter in the range of 8–17 nm. The PANI-NFs and PANI-NFs/O-MWCNT nanocomposites demonstrated excellent electrochemical properties, with specific capacitances of up to 0.94–1.23 F cm⁻² and 1410–2074 F/g, respectively, and with good rate capability. These characteristics are confirmed by the relaxation time constant τ₀ (41 and 8 ms, respectively) and lower internal R₀/interfacial charge transfer R_Փ resistances of around 0.2 Ω, as well as diffusion coefficients of around 10⁻⁷ and 3.7 × 10⁻⁷ cm²/s. This breakthrough in nanofiber synthesis paves the way for practical applications in diverse domains, from high-performance energy storage to biosensing and beyond, where the unique electroactive properties of the nanocomposites can be leveraged to achieve exceptional results. Full article

Satellite remote sensing offers a cost-effective solution for the continuous monitoring of black and odorous water bodies (BOWs). However, limitations in spatial and spectral resolution hinder the quantitative inversion of water quality parameters and the precise assessment of risk levels using satellite data alone. To address this challenge, this study proposes a synergistic approach combining satellite and Unmanned Aerial Vehicle (UAV) remote sensing to rapidly identify potentially polluted water bodies and quantitatively assess their risk levels. First, a Black and Odorous Water Index (MBOWI) was constructed based on reflectance characteristics in the visible to near-infrared bands to screen for potential black and odorous water bodies using satellite imagery. Subsequently, high-resolution multispectral UAV imagery, integrated with in situ sampling data, was employed to develop machine learning models for inverting key water quality parameters, including Chemical Oxygen Demand (COD), Dissolved Oxygen (DO), Total Phosphorus (TP) and Ammonia Nitrogen (NH₃-N). Comparative analysis of Polynomial Regression (PR), Random Forest (RF), and Simulated Annealing-optimized Support Vector Regression (SA-SVR) revealed that RF and SA-SVR exhibited superior performance in inverting four non-optically active water quality parameters due to their robust nonlinear fitting capabilities, with the mean Adjusted Coefficient of Determination ($R_{adj}^2$) ranging from 0.57 to 0.69. Water quality classification based on the single-factor worst-case method achieved an overall accuracy of 0.70 across validation samples. Notably, for Class V (heavily polluted) water bodies, both classification accuracy and recall rate reached 0.89, demonstrating the model’s high precision in identifying high-risk waters. Finally, the proposed framework was applied to northern Zhejiang Province to assess seven potential black and odorous water bodies, successfully identifying four as high-risk and one as low-risk. This study validates satellite and UAV synergistic remote sensing for the hierarchical risk management of black and odorous water bodies. Full article

Background: Photodynamic therapy (PDT) offers a promising complementary strategy for treating glioblastoma multiforme (GBM); however, limited control over photosensitizer activation and reduced efficacy under hypoxic conditions remain significant limitations. Methods: In this study, we present the synthesis and functional evaluation of Gal-SiX, an enzymatically activatable Si-xanthene-based activatable PDT agent designed to address these challenges. Prepared via an improved 10-step synthetic route, Gal-SiX exhibits clear turn-on fluorescence and absorbance responses upon β-galactosidase activation and efficiently generates reactive oxygen species in aqueous media. Results: Mechanistic studies revealed that Gal-SiX enables both Type I and Type II PDT pathways, a favorable feature for GBM environments characterized by restricted oxygen availability. In vitro assays conducted on U87MG glioblastoma cells and L929 healthy fibroblasts demonstrated light-dependent cytotoxicity, with IC₅₀ values of 3.30 μM and 7.19 μM, respectively. Gal-SiX also showed minimal dark toxicity (>80 μM) and potent light-induced cytotoxicity, yielding a phototoxicity index of 24.8 in glioblastoma cells. Confocal imaging and MTT assays consistently confirmed enzymatic activation and effective PDT response at the cellular level. Conclusions: Overall, this work introduces the first activatable Si-xanthene-based PDT agent for glioblastoma and provides the first evidence that the Si-xanthene scaffold can support dual Type I/II phototoxicity. These results underscore Gal-SiX’s potential as a PDT platform for addressing the unique constraints of GBM biology. Full article

The PGM-free Fe–Ni–Co trimetallic catalysts developed in this study demonstrated outstanding performance for the oxygen evolution reaction (OER), achieving overpotentials as low as 300 mV at 10 mA cm⁻² in rotating disk electrode (RDE) measurements, a value competitive with the most efficient non-noble electrocatalysts reported in the literature. This study validates the strong catalytic performance of the baseline trimetallic configuration and provides important insights into the relationships among synthesis, structure, and morphology that govern catalyst activity. In particular, the findings highlight that although organic additives can be promising modifiers, the interaction between precursors and transition metals must be carefully controlled to avoid active-site isolation when designing efficient catalysts for sustainable hydrogen production. Actually, to further enhance catalytic activity, the nitrogen-rich precursor melamine was introduced into the supported trimetallic catalyst and then carbonized. However, no improvement in OER performance was observed. During carbonization, melamine promotes the formation of tip-growth carbon nanotubes, which mechanically disrupt the catalyst structure and degrade the supported active phase. Full article

Background: Neuronal apoptosis is the core pathological mechanism of cerebral ischemic–reperfusion injury (CIRI); although Astragaloside IV (AS-IV) has demonstrated neuroprotective activity against CIRI, its specific molecular mechanisms underlying the regulation of this apoptosis-related pathway remain to be systematically elucidated. Methods: We establish an in vivo model of middle cerebral artery occlusion/reperfusion (MCAO/R) in rats and an in vitro model of oxygen–glucose deprivation/reperfusion (OGD/R) in PC12 cells. Six core apoptotic proteins, including CytC, Apaf-1, BAX, Bcl-2, Caspase3, and Caspase9, were detected using neurological function scoring, TTC/HE/Nissl staining, TUNEL staining, Western blot, and immunofluorescence techniques. Molecular docking and molecular dynamics simulation were utilized to analyze the binding affinity between AS-IV and the aforementioned apoptotic proteins. Results: Molecular docking and dynamics simulation demonstrated AS-IV stably binds six core apoptotic proteins, and comparative analysis with target-specific reference ligands identified Apaf-1 as its primary target with the most favorable binding properties. In rat MCAO/R models, AS-IV alleviated neurological deficits, reduced cerebral infarct volume and improved brain pathological damage; in PC12 cell OGD/R models, it decreased neuronal apoptosis. Western blot and immunofluorescence confirmed AS-IV downregulated pro-apoptotic proteins (cytoplasmic CytC, Apaf-1, BAX, cleaved-Caspase9/3) and upregulated anti-apoptotic Bcl-2. Conclusions: This study clarifies the anti-apoptotic molecular mechanism of AS-IV, it alleviates CIRI by targeting the CytC/Apaf-1 mitochondrial apoptotic pathway. Full article

Anaerobic biodegradation of aromatic contaminants is constrained by unfavorable thermodynamics in the absence of oxygen and high activation energy required for aromatic ring-cleavage. Thus, identifying factors that enhance anaerobic aromatic degradation by microorganisms such as the Geotalea daltonii strain FRC-32 is crucial. Trace elements (TEs) function as rate-limiting cofactors for anaerobic carbon catabolism enzymes. Cobalt, molybdenum, selenite, and tungsten amendments stimulated G. daltonii growth on benzoate and anaerobic benzoate oxidation. To elucidate mechanisms of cobalt amendments in G. daltonii, we characterized a putative cobalt-specific energy-coupling factor (ECF) transporter CbiMNQO. The cbiMNQO genes form an operon and were upregulated under cobalt limitation, indicating a role in cobalt homeostasis. In silico structural predictions of CbiMNQO, ligand binding predictions of CbiMN, and alignment to known cobalt transporters suggested that CbiMNQO facilitates cobalt transport in G. daltonii. Structural and ligand binding predictions of BamB and BamF, and transcript-level analyses indicated that bamB and bamF, encoding molybdenum- and selenite–tungsten-dependent benzoyl-CoA reductase-subunits, modulate TE-dependent anaerobic benzoate degradation. Regulation of bamB and bamF in response to TE amendments corresponded with enhanced anaerobic benzoate oxidation, indicating stimulated benzoate dearomatization. Collectively, our findings demonstrated that TE amendments enhance anaerobic aromatic metabolism in G. daltonii and may contribute to anaerobic bioremediation. Full article

Silver nanoparticles synthesized using natural polysaccharides have received attention for their biocompatibility and potential selective anticancer activity. In this study, the physicochemical properties and biological activity of silver nanoparticles prepared using gums from Acacia senegal (ASS) and Acacia seyal (ASY) were compared. The gums were analyzed to determine their physicochemical characteristics and used as natural reducing and stabilizing agents in nanoparticle synthesis. The resulting nanoparticles were characterized using UV–visible spectroscopy, FTIR, dynamic light scattering, and zeta potential analysis. Their cytotoxicity was evaluated in MCF-7 breast cancer cells and HEK-293 normal cells using MTT assay, flow cytometry, and intracellular reactive oxygen species (ROS) measurement. Both gums showed properties consistent with Gum Arabic, with a higher protein content in ASS. ASS-derived nanoparticles were smaller and had greater colloidal stability. Both formulations reduced MCF-7 cell viability in a dose-dependent manner, with lower IC₅₀ values observed for the ASS-based nanoparticles. Apoptosis induction was associated with increased ROS generation. Limited cytotoxicity toward HEK-293 cells resulted in favorable selectivity indices. Acacia gum–mediated silver nanoparticles demonstrate selective anticancer activity, and gum composition significantly influences nanoparticle stability and bioactivity, supporting their potential application in breast cancer nanotherapy. Full article

Background: Cancer has emerged as the primary cause of death worldwide in recent years. Current cancer treatment strategies require improvement, creating a pressing need for the development of novel therapeutic agents. This study investigated the anticancer effects of a series of newly synthesized tri- and difluoromethylated spiro[5.5]trienone compounds and evaluated the antitumor efficacy of a lead compound, 3s. Methods: The methyl thiazolyl tetrazolium (MTT) assay was used to assess the effect of the trienone compounds on the growth of cancer cells. Cell cycle distribution and intracellular reactive oxygen species (ROS) levels were analyzed by flow cytometry. Protein expression was examined by Western blot. A mouse xenograft model was utilized to test the anticancer effects and toxicity of 3s in vivo. Results: All 21 tri- and difluoromethylated spiro[5.5]trienones exhibited inhibitory effects on the growth of cancer cells. Among them, compound 3s showed the strongest inhibitory effect. It induced cell cycle arrest at the G2/M phase and promoted apoptosis. Mechanistically, 3s activated JNK and ERK signaling and elevated intracellular ROS levels. Furthermore, in a mouse xenograft model, 3s significantly inhibited tumor growth with minimal toxicity. Conclusions: Compound 3s exhibits potent anticancer efficacy both in vitro and in vivo. The discovery of 3s offers new potential for cancer therapy. Full article

Human induced pluripotent stem cell (iPSC)-derived brain organoids have emerged as powerful three-dimensional (3D) platforms for modeling human neurodevelopment and neurological disorders. However, the absence of a functional vascular network remains a critical limitation, restricting oxygen and nutrient delivery, impairing metabolic stability, and constraining long-term maturation. Conventional extracellular matrix (ECM) mimetics, such as Matrigel and other static synthetic hydrogels, provide biochemical support but fail to recapitulate the dynamic remodeling that characterizes the developing neurovascular niche. Recent advances in stimuli-responsive hydrogels offer spatiotemporal control over matrix stiffness, degradability, viscoelasticity, and biochemical cue presentation. In this review, we discuss dynamic hydrogel systems within a structure–property–function framework, highlighting how network chemistry and architecture may regulate endothelial sprouting, lumen formation, vascular stabilization, and neurovascular unit maturation in vascularized brain organoid models, based on evidence from both organoid studies and related biomaterial or vascular systems. Photoresponsive, enzyme-cleavable, thermo-responsive, supramolecular, bio-orthogonal click-based, and bioprinted platforms are discussed with emphasis on mechanotransduction, angiocrine signaling, and barrier specialization. Functional outcomes, including trans-endothelial electrical resistance, selective permeability, transporter expression, electrophysiological integration, and sustained perfusion, are discussed alongside translational challenges such as cytocompatibility, oxidative stress, scalability, and regulatory feasibility. Collectively, dynamic hydrogels provide a versatile biomaterial strategy for improving vascularization and aspects of functional maturation in brain organoid models with enhanced physiological relevance. Ultimately, stimuli-responsive hydrogel systems may serve as enabling platforms for engineering vascularized brain organoids and advancing human-relevant neurovascular disease modeling. Full article

This study investigates the formation mechanism of lactic-acid-derived coatings produced by open-air atmospheric-pressure plasma polymerization. A comparison of nebulization and bubbling precursor-delivery methods using FT-IR and XPS showed that the bubbling method facilitated plasma-assisted chemical bonding, including the possible formation of copper(II) lactate-like interfacial species and the retention of carbonyl-containing functional groups. However, the present dataset does not provide direct, discriminating evidence for a specific metal-lactate interfacial species, and alternative interpretations such as adsorption, oxidation, hydroxylation, or generic oxygenated carbon deposition cannot be excluded. Time-dependent analysis revealed a transition from oxygen-rich functional layers at short plasma exposure to carbon-rich overlayers at longer exposure, suggesting a fragmentation-recombination mechanism that is consistent with the formation of a metal-lactate-like interfacial region and a carbon-rich overlayer, while alternative interpretations related to signal attenuation and non-uniform coverage remain possible. Antibacterial testing revealed that the observed bacterial responses were not attributable to an intrinsic antibacterial property of the deposited films, but were instead strongly dependent on the underlying substrate chemistry and exposure time. C1100 retained the inherent antibacterial activity of copper, SUS430 showed no activity due to the absence of film formation, and SPCC exhibited only a transient effect attributed to lactic-acid-induced local acidification. Overall, the study elucidates the plasma-assisted deposition mechanism of lactic-acid-derived coatings under open-air conditions and highlights the critical role of interface chemistry in achieving stable and substrate-independent functional properties. Full article

Intensive recirculating aquaculture systems are vulnerable to spikes of nitrite, which oxidizes hemoglobin to methemoglobin and compromises oxygen transport. Methylene blue (MB) is a classical antidote for methemoglobinemia, yet its use in fish has been limited to injections or immersion baths that are impractical for large-scale operations. This study assessed whether MB incorporated into a medicated feed could mitigate acute nitrite intoxication in Nile tilapia. Fish received either a control diet or 0.1% MB diet. After five days on the experimental diets, fish were exposed to nitrite for 48 h. Control fish experienced five deaths, whereas no mortality or behavioral distress was observed in MB-treated fish. Hematology indicated significantly lower circulating methemoglobin concentration in the MB group, while the control fish had higher hemoglobin concentration and erythrocyte counts, consistent with compensatory erythropoiesis. Gill histology revealed preserved lamellae with only mild changes in MB-fed fish, whereas control fish displayed lamellar aneurysm, edema, capillary congestion, fusion and epithelial hyperplasia. Therefore, oral MB administration appears to ameliorate the physiological consequences of acute nitrite exposure, offering a scalable intervention for emergency management of nitrite spikes. Future work should define dose–response relationships, evaluate post-exposure rescue, quantify gill lesions and assess MB residues in food fish. Full article

This project investigates how the orientation of the carbon cathode with a single-sided microporous layer (MPL) affects battery performance through electrochemical tests, neutron tomography, and titration experiments. The titration experiment quantitatively assesses the amount of solid product (Li₂O₂) deposited on the electrode surface. In addition, neutron imaging with a 16 µm voxel resolution provides details on the spatial distribution of the solid product within the porous electrodes. Additionally, the performance impact of two electrolyte solvents, tetra ethylene glycol dimethyl ether (TEGDME) and dimethyl sulfoxide (DMSO), is evaluated when used to soak the carbon cathode. The cathode orientation where the MPL faces toward the electrolyte and separator reaches higher discharge and charge capacities and greater average discharge voltages compared to when the MPL faces away from the separator. Batteries discharged with DMSO as the solvent have a 64.86% decrease on average in discharge capacity compared to batteries using TEGDME as the solvent. Both the titration experiments and neutron imaging confirmed that the amount of solid products exhibits a linear correlation with the discharged capacity. Additionally, electrolytes with a high donor number, such as DMSO, were found to result in a smaller amount of Li₂O₂ deposited on the electrode surface. Full article

Chronic diabetic wound remain difficult to heal because persistent inflammation, oxidative stress, and impaired regeneration delay repair, while effective noninvasive options are limited. In this study, graphene-based far-infrared radiation (FIR) therapy was evaluated in a streptozotocin (STZ)-induced diabetic rat full-thickness wound model, and mechanisms were examined in vivo and in vitro. Wound closure was quantified by serial imaging, whereas tissue remodeling and angiogenesis were assessed by H&E and Masson’s trichrome staining and CD34-based analyses. Transcriptomic responses were profiled by RNA sequencing with qRT-PCR validation, immune phenotypes were characterized by immunofluorescence, and high-glucose cell assays were performed. Re-epithelialization, collagen deposition, and neovascularization were quantified histologically. These datasets enabled integrated evaluation of inflammation, oxidative stress, and repair programs over time. Graphene FIR accelerated closure, reaching 83.9% healing by day 14 vs. 66.8% in untreated controls. Treatment was associated with downregulation of Cxcl2/Cxcl3, suppression of M1 polarization with enhanced M2 polarization, and reduced ROS accumulation. Consistently, NF-κB signaling was inhibited, supporting restoration of a pro-regenerative microenvironment. Collectively, graphene FIR represents a promising noninvasive strategy for diabetic wound repair via coordinated immunomodulatory and antioxidant actions. Full article