Search Results (9,034)

Developing highly efficient and stable electrocatalysts from inexpensive and earth-abundant elements represents a significant advancement in overall water splitting (OWS). This study focuses on the synthesis and evaluation of palladium-modified cobalt–phosphorus (PdCoP) and cobalt–iron–phosphorus (PdCoFeP) coatings for use as electrocatalysts in hydrogen evolution (HER), oxygen evolution (OER) and overall water splitting (OWS) in alkaline media. A facile electroless plating method is adopted to deposit the CoP and CoFeP coatings onto a copper surface (Cu sheet), with sodium hypophosphite (NaH₂PO₂) acting as the reducing agent. Pd crystallites were incorporated on CoP and CoFeP coatings using the galvanic displacement method. This study details morphological characterization (using SEM, EDX, and XRD), as well as electrochemical activity testing, for both HER and OER using linear sweep voltammetry (LSV) at different temperatures. The stability of the catalysts for HER was evaluated using chronoamperometry (CA) and chronopotentiometry (CP). The results show that the Pd-modified CoFeP and CoP catalysts exhibited lower overpotentials of 207 and 227 mV, respectively, for HER and 396 mV for OER at a current density of 10 mA cm⁻² compared to the unmodified CoFeP and CoP catalysts. The innovation achieved in this study lies in combining a facile, low-cost deposition method (electroless plating followed by galvanic displacement) with a novel, highly effective ternary composition (PdCoFeP) that exploits synergistic electronic and morphological effects to achieve superior bifunctional performance for alkaline OWS, achieving a low cell voltage of 1.69 V at a current density of 10 mA cm⁻². Overall, this research demonstrates that these synthesized materials are promising candidates for sustainable and economical hydrogen production. Full article

Al–Cu–Mg composites reinforced with sub-micron tungsten carbide (WC) particles were synthesized by powder metallurgy and subjected to T6 heat treatment to clarify the interplay between dispersion strengthening and precipitation hardening. Composites with 1–3 wt.% WC (average size 0.8 μm) were solution-treated at 540 °C for 3 h, water-quenched, and aged at 195 °C for up to 100 h. Microstructural analyses confirmed a uniform distribution of WC and demonstrated that its presence did not modify the dissolution–precipitation sequence of the Al-Cu-Mg matrix. Transmission Electron Microscopy observations provided direct evidence of θ′ (Al₂Cu) precipitates. The 3 wt.% WC composite reached peak hardness after 5 h (78 HRF), a 15% increase over the T6-treated unreinforced alloy, and exhibited a 40% higher yield strength (330 MPa). These improvements were attributed to the combined effects of Orowan strengthening and age-hardening precipitates (θ′). The results demonstrate that integrating powder metallurgy, sub-micron WC reinforcement, and T6 treatment is an effective route to enhance strength in Al–Cu–Mg alloys without delaying aging kinetics. Full article

Although covalently crosslinked gelatin hydrogels have been investigated for use in 3D cell culture due to inherent bioactivity and proliferation within the denatured collagen precursor, the stability of the matrix, and relatively inexpensive synthesis, current systems lack precise control over mechanical properties, including homogeneity, stiffness, and efficient diffusion of nutrients to embedded cells. Difficulties in modifying gel matrix composition and functionalization have limited the use of covalently crosslinked gelatin hydrogels as a three-dimensional (3D) cell culture medium, lacking the ability to tailor the microenvironment for specific cell types. In addition, the currently utilized chain-growth photopolymerization mechanism for crosslinking hydrogels has a potential for side reactions between the matrix backbone and components of the cell surface, requires a high concentration of radicals for initiation, and only cures with long irradiation times, which could lead to cytotoxicity. To overcome these limitations, a superfast curing reaction mechanism, in which a thiol monomer reacts efficiently with non-homopolymerizable alkenes, is suggested. This mechanism reliably produces a well-defined matrix that does not require a high radical concentration for photoinitiation. Mechanical customization of the hydrogel is largely achievable through variation in degree of functionalization of the gelatin backbone, dependent on reaction conditions such as pH, allyl concentration, and time. This work provides a mechanistic framework for GelAGE hydrogel fabrication by elucidating the molecular mechanism of gelatin functionalization with AGE and the thiol-ene crosslinking reactions controlling network stiffness. These insights provide the foundation for engineering hydrogels that mimic the viscoelastic and structural characteristics of cartilage, enabling advanced in vitro models for osteoarthritis research. Full article

This study evaluated the effects of different sintering protocols on the mechanical and microstructural properties of two multilayered zirconia materials: strength-gradient zirconia (KATANA YML) and color-gradient zirconia (KATANA UTML). Bar-shaped specimens were fabricated from both zirconia types. Three sintering protocols were applied: a manufacturer-recommended conventional protocol (7 h at 1550 °C), a high-speed protocol (54 min at 1600 °C), and a modified high-speed protocol (51 min at 1600 °C). Eighty-four specimens underwent three-point flexural strength testing. SEM and XRD analyses were used to assess microstructure and phase composition. No significant differences in flexural strength were found among sintering protocols (p > 0.05), but YML consistently showed higher strength than UTML (p < 0.05). The highest strength in YML was observed after high-speed sintering, followed by the shortened and conventional protocols. In UTML, the modified protocol yielded the highest strength, followed by the high-speed and then conventional protocol. SEM revealed finer, more homogeneous grains with shorter sintering times. XRD confirmed stable phase composition across all protocols. High-speed and modified high-speed sintering protocols can reduce processing time without compromising zirconia’s mechanical performance. Material type had a greater effect on flexural strength than sintering time, though microstructure was protocol dependent. Proper selection of zirconia type and sintering strategy is essential for optimal outcomes. Full article

Phenolic compounds such as resorcinol (RS) have negative impacts on aquatic life, the environment, and human health. Thus, it is necessary to develop sensing devices for the monitoring of RS. The electrochemical method is one of the most significant approaches for the determination of toxic substances. In electrochemical methods, electrode modifiers play a vital role and affect the sensing performance of the electrochemical sensors. Thus, the selection of efficient electrode material is of great importance. In recent years, various electrode modifiers such as graphene, metal–organic frameworks (MOFs), MXenes, metal oxides, polymers, and composite materials have been extensively used for the fabrication of RS sensors. In this review, we have summarized the reported electrode modifiers for the fabrication of RS electrochemical sensors. Various electrochemical sensing techniques, including differential pulse voltammetry (DPV), square wave voltammetry (SWV), amperometry (Amp), cyclic voltammetry (CV), and linear sweep voltammetry (LSV) have been discussed. This review provides an overview of a large number of electrode modifiers for the determination of RS. The limitations, challenges, and future perspectives for RS sensors are discussed. We believe that the present review article is beneficial for the scientific community and electrochemists working on the construction of RS sensors. Full article

Apple juice is widely consumed across global beverage markets. Its colour and cloudy appearance play a crucial role in consumer perception. Various physical treatments are available to modify juice turbidity and preserve colour, among which filtration and high-pressure homogenisation are considered the most respectful to the raw juice composition. In this study, red apple juice from the Kissabel^® Rouge cultivar was filtered using membranes ranging from 100.0 to 0.2 μm and homogenised at pressures from 20 to 60 MPa. The physicochemical properties were then evaluated after 205 days of storage at two different temperatures. Microfiltration (<5.0 μm) increased juice lightness (87 vs. 66), but compromised cloud and colour stability by reducing cloudiness by 15 days compared with the unfiltered juices. Homogenisation increased turbidity, both in absolute value and during storage, which is typically appreciated in 100% apple juices. Finally, colloidal stability was affected by both treatments; combining mild filtration with low homogenisation pressure yielded the highest colloidal repulsion (−16.3 mV). Elevated storage temperatures generally diminished juice quality in terms of colour tone and intensity, and accelerated particle sedimentation. Full article

The photocatalytic degradation of Crystal Violet (CV) using ZnO-based nanomaterials presents a promising solution for addressing water pollution caused by synthetic dyes. This review highlights the exceptional efficiency of ZnO and its modified forms—such as doped, composite, and heterostructured variants—in degrading CV under both ultraviolet (UV) and solar irradiation. Key advancements include strategic bandgap engineering through doping (e.g., Cd, Mn, Co), innovative heterojunction designs (e.g., n-ZnO/p-Cu₂O, g-C₃N₄/ZnO), and composite formations with graphene oxide, which collectively enhance visible-light absorption and minimize charge recombination. The degradation mechanism, primarily driven by hydroxyl and superoxide radicals, leads to the complete mineralization of CV into non-toxic byproducts. Furthermore, this review emphasizes the emerging role of Artificial Neural Networks (ANNs) as superior tools for optimizing degradation parameters, demonstrating higher predictive accuracy and scalability compared to traditional methods like Response Surface Methodology (RSM). Potential operational challenges and future directions—including machine learning-driven optimization, real-effluent testing potential, and the development of solar-active catalysts—are further discussed. This work not only consolidates recent breakthroughs in ZnO-based photocatalysis but also provides a forward-looking perspective on sustainable wastewater treatment strategies. Full article

The growing demand from the automotive industry for lightweight, high-performance, and advanced manufacturing techniques for efficient and cost-effective production has accelerated the adoption of fiber-reinforced polymer composites. However, considering the manufacturing complexity of these materials, design remains challenging due to the intricate and interdependent relationships between the process conditions, the part geometry, and the resulting microstructure and quality. This research utilized the Autodesk Moldflow Insight software to design an injection molding process for the manufacturing of discontinuous glass fiber-reinforced polymer parts through computer modeling. A geometrically complex car fender was used as a case study. The effects of various process parameters, particularly gate locations, on the injection-molded parts’ properties (such as the fiber orientation, volumetric shrinkage, and shear rate) were investigated. Multiple injection molding process configurations were designed and simulated, including three, four, and five gates at varying locations. Based on the optimal performance (i.e., low shrinkage, a consistent fiber orientation, and a controllable shear rate), an optimal configuration with four gates at appropriate locations (corresponding to the second gate location set) was identified based on multicriteria decision-making analysis, i.e., volumetric shrinkage of ${8.5}_{-2.2}^{+1.4}\%$, a fiber orientation tensor of 0.927 ± 0.011, and a stable shear rate < 74,324 (1/s). A reduced strain closure model (modified Folgar–Tucker model) was used to predict the glass fiber orientation. A multicriteria decision-making technique, based on similarity ranking with an ideal solution, was employed to optimize the gate location. The simulation results clearly demonstrate that the gate placement is crucial for material behavior during molding and for reducing common defects. The simulation-based injection molding process design for the manufacturing of discontinuous fiber-reinforced polymer parts proposed in this paper can improve the production efficiency, reduce trial-and-error rates, and improve part quality. Full article

Despite the widespread use of photopolymerizable methacrylate resins in additive manufacturing, their potential for creating functional biomedical materials remains untapped. Standard resins, while possessing good technological properties, are typically biologically inert and unable to combat such a critical problem as bacterial colonization. In this work, we propose incorporating selenium nanoparticles (Se NPs) into a photopolymerizable resin based on methacrylate monomers to obtain functional composite materials in the MSLA printing process. Composite material samples made from modified resins showed no structural surface defects and were characterized by a non-uniform distribution of NPs in volume and demonstrated a higher degree of monomer conversion. The materials demonstrated significant antioxidant activity, removing OH-radicals and H₂O₂ and reducing the level of biomarkers of oxidative damage (8-oxoguanine in DNA and long-lived reactive protein species). A dose-dependent bacteriostatic effect was observed in E. coli cell cultures against a background of high cytocompatibility with human cell cultures. The developed photopolymerizable resins modified with Se NPs allow obtaining products that combine the properties of a bacteriostatic agent with antioxidant properties and high biocompatibility, which is of considerable interest in terms of materials for biomedical applications. Full article

The high stability of chelated heavy metal complexes like Cu-EDTA renders their effective removal from industrial wastewater a persistent challenge for conventional treatment processes. This study developed a sustainable and high-performance CuO-modified biochar (CuO-BC) from corn straw waste for peroxydisulfate (PDS)-activated degradation of Cu-EDTA. Through systematic optimization, hydrothermal co-precipitation using copper acetate as the precursor followed by secondary pyrolysis at 350 °C was identified as the optimal synthesis strategy, yielding a dandelion-like structure with highly dispersed CuO on the BC surface. It achieved 93.8% decomplexation efficiency and 57.3% TOC removal within 120 min under optimized conditions, with an observed rate constant (K_obs) of 0.0220 min⁻¹—five times higher than BC. Comprehensive characterization revealed that CuO-BC possessed a specific surface area and pore volume of 4.36 and 15.5 times those of BC, along with abundant oxygen-containing functional groups and well-exposed Cu–O active sites. The enhanced performance is attributed to the synergistic effects of hierarchical porosity facilitating mass transfer, uniform dispersion of CuO preventing aggregation, and surface functional groups promoting PDS activation. This work presents a green and scalable approach to transform agricultural waste into an efficient metal oxide-BC composite catalyst, offering dual benefits of environmental remediation and resource valorization. Full article

Nitrogen fertilization is essential for balancing maize yield, grain composition, and environmental sustainability. This study aimed to evaluate the relationship between nitrogen (N) supply, grain quality traits, and yield potential using UAV-based Normalized Difference Vegetation Index (NDVI) monitoring in a long-term fertilization field experiment in Eastern Hungary. Six N levels (0–300 kg ha⁻¹) were tested during two consecutive growing seasons (2023–2024) under varying climatic conditions. The obtained results showed that moderate N doses (120–180 kg ha⁻¹) provided the optimal nutrition level for maize, significantly increasing yield compared to the control (+5.086 t ha⁻¹ in 2024), while excessive fertilization above 180 kg ha⁻¹ did not result in any substantial yield gains; however, it significantly modified grain composition. Higher N supply enhanced protein content (+0.95% between 0 and 300 kg ha⁻¹) and reduced starch percentage, confirming the protein–starch trade-off, whereas oil content was less affected by nitrogen fertilization, similarly to previous results. The strongest correlation between NDVI values and yield was measured at the post-silking stage (112 DAS; R = 0.638 in 2023, R = 0.634 in 2024), indicating the suitability of NDVI monitoring for in-season yield prediction. Overall, NDVI-based monitoring proved effective not just for optimizing N management but also for supporting site specific fertilization strategies to enhance maize productivity and nutrient use efficiency. Full article

The increased production of sewage sludge is a major environmental concern as the sludge contains hazardous components, particularly human bacterial pathogens (HBPs). Transit of sewage sludge through the earthworm gut reduce or even eliminate HBPs and modify bacterial taxonomic and functional composition. However, it is unclear whether the effect is general or dependent on the type of sewage sludge involved. We characterized the taxonomic and functional profiles of bacterial assemblages in sewage sludge from different wastewater treatment plants (WWTPs), before (sludge) and after earthworm gut transit (casts). We found that composition and diversity of both taxonomic and functional bacterial communities of sludge and casts were significantly different. However, these differences varied among WWTPs with both increases and decreases in composition and diversity after gut transit. Interestingly, most bacterial taxa present in earthworm casts were not detected in the original sewage sludge. All sludge samples initially contained low levels of HBPs, which were significantly reduced or eliminated in earthworm casts. Nevertheless, gut transit increased the abundance of some HBPs. Further studies should determine whether vermicomposting effectively eliminates these HBPs and whether the differences in earthworm cast bacterial communities, which are dependent on the sewage sludge source, persist in the final vermicompost. Full article

Ethylene–vinyl acetate (EVA) is a versatile polymer for applications in dental devices; however, its vulnerability to microbial colonization increases with long-term use. This study evaluates EVA composites modified with silver–sodium–hydrogen–zirconium phosphate (SP) particles, aimed at enhancing antimicrobial performance while preserving key functional properties. Composites containing 1–16 wt.% SP were prepared via solvent-based and mechanical compounding routes, with scanning electron microscopy confirming correct filler distribution across processing methods. Antimicrobial assays revealed a pronounced reduction in Streptococcus mutans and Candida albicans levels, reaching 88% and 98% antimicrobial efficacy, respectively, at 16 wt.% SP. Cytotoxicity testing with L-929 fibroblasts demonstrated maintained cell viability above the 70% threshold, confirming non-cytotoxicity. Mechanical characterization indicated marginal increases in hardness, slight tensile strength reduction at higher filler loadings, while other physicochemical and thermal analyses showed minimal impact on polymer performance. These findings indicate balanced antimicrobial activity with other biofunctional properties. Full article

This study systematically assessed the regulatory effects of Yunnan Lufeng aromatic vinegar (LFAV) on the intestinal microbiota composition, short-chain fatty acids, and cecal metabolites in mice. 16S rRNA high-throughput sequencing revealed that LFAV intervention significantly altered gut microbiota diversity; the M-L group exhibited 19.98% unique operational taxonomic units, while both Chao1 (496.63 ± 42.14) and Shannon indices (6.68 ± 0.32) increased by 37.46% and 3.25%, respectively, compared to the blank group, indicating enhanced microbiota richness. Species composition analysis demonstrated that the relative abundance of Firmicutes reached 75.4% in the M-L group, a 24.4% increase over the B group, whereas Bacteroidetes abundance decreased to 8.2%. GC-MS analysis detected peak butyric acid levels in the M-L group. Untargeted metabolomics identified 520 metabolites, of which 60 were significant differential metabolites. Cluster heatmap and Z-score analyses demonstrated that LFAV intervention significantly modulated mouse metabolites. KEGG pathway enrichment analysis indicated the upregulation of pathways including neuroactive ligand–receptor interactions and renin secretion. Pearson correlation analysis showed a strong positive correlation (p < 0.01) between Lactobacillus and acetic acid/butyric acid; concurrently, increased Lactobacillus proliferation and elevated butyric acid levels were observed in the M-L and M-M groups. These findings suggest that LFAV intervention promotes the proliferation of beneficial bacteria, which may improve intestinal health. Collectively, LFAV significantly modified gut microbiota structure and metabolites in mice, highlighting its potential as a natural prebiotic or functional food ingredient and providing a scientific basis for developing functional vinegar products. Full article

Clay/natural rubber (Clay–NR) nanocomposites are a sustainable material class with a wide range of applications. The type and amount of the filler added to the rubber matrix promote significant changes in the matrix properties. Montmorillonitic clays (MMT) are mineral, natural fillers. This study investigates the effect of a modified Brazilian polycationic MMT on the nanocomposite rheology and mechanical properties. The MMT was incorporated into a NR matrix in its natural state, and after modification by cation exchange (MMT^Na) and organophilization (MMT^ORG), at concentrations of 2.5 and 5 phr (parts per hundred parts of rubber). The natural and modified clays were characterized by XRD, FTIR, BET, and SEM/EDS. Mechanical tests (tensile strength, elongation at break, and modulus at 100%) indicated that the use of MMT^Na led to increased strength and modulus, whereas a minor decrease in the elongation was observed. However, the use of MMT^ORG yielded the most significant improvements in the mechanical properties. The rheology tests indicated that the Payne effect was not observed, and the strain-dependent behavior arises from matrix-dominated mechanisms, rather than disruption of a filler network. Vulcanization curves showed that the NR-MMT^ORG composites exhibited higher torque values, corroborated by higher crosslink densities. These findings highlight the critical role of cation exchange modification in optimizing MMT dispersion and interfacial interactions within NR matrices, providing design principles for high-performance sustainable nanocomposites. Full article