Search Results (1,852)

Graphitic carbon nitride (g-C₃N₄) has proved to be an excellent and versatile catalyst, devoid of any metal, for the sustainable production of heterocycles. Owing to its nitrogen-rich conjugated framework, which provides Lewis-basic and hydrogen-bonding sites and enables tuneable electronic properties, together with its excellent thermal and chemical stability and recyclability, graphitic carbon nitride (g-C₃N₄) has emerged as a versatile metal-free heterogeneous catalyst for the synthesis of heterocycles. In this review, a critical analysis of recent trends in g-C₃N₄-catalysed multicomponent reactions (MCRs) and their related approaches towards the synthesis of pharmaceutically important heterocycles is provided. This review highlights current developments in g-C₃N₄-catalysed multicomponent reactions (MCRs) for the synthesis of biologically and pharmaceutically relevant heterocyclic frameworks, including pyrimidines, pyridines, pyrans, chromenes, tetrazoles, quinolines, imidazoles, triazoles, and spirocyclic heterocycles. Mechanistic aspects, including Lewis acid–base mechanism, photocatalysis and formation of radicals, have been highlighted to establish the correlation between catalyst properties and the reaction outcomes. The sustainability of the methodology is assessed through reaction mass efficiency, atom economy, process mass intensity, E-factor, energy efficiency and catalyst reusability. Critically analysed advancements have been made regarding the development of hybrid catalysts based on g-C₃N₄. Challenges faced during catalyst deactivation, utilization of visible light, scalability and incompleteness in green metric reporting are addressed. Full article

The growing global demand for electrical energy and the necessity for decarbonization highlight the importance of assessing the rational use of renewable resources and energy. Thus, this study examined the energy and exergy performance of two offshore wind energy destinations and conversions in Brazil: (i) storage in chemical bonds of hydrogen and ammonia for export and (ii) direct use of electrical energy in the Brazilian National Interconnected System (SIN). The method was based on an integrated exergy analysis, complemented by indicators such as Energy Return on Energy Investment (EROI), considering the entire production chain: seawater desalination, electrolysis, cryogenic air separation, ammonia synthesis and transport, and the electrical energy pathway through the SIN grid. The results demonstrated that the conversion and transport of ammonia lead to lower efficiencies, greater exergy losses, and lower EROI, whereas the direct use of electrical energy through the integrated system proved to be more efficient, with higher EROI and lower exergy losses. From a public policy perspective, the findings suggest that prioritizing hydrogen and ammonia production for export may result in the externalization of the main exergy and decarbonization benefits associated with their final use. The results therefore highlight the importance of aligning emerging hydrogen strategies with domestic decarbonization priorities, particularly by prioritizing the use of hydrogen and its derivatives in hard-to-abate sectors of the Brazilian economy. Full article

The development of sustainable and efficient methods for carbon–carbon (C–C) bond formation remains the main objective in modern organic synthesis. In recent years, photocatalysis has developed as a suitable alternative to conventional transition-metal-catalyzed approaches, offering mild reaction conditions, high functional-group tolerance, excellent atom economy, and the ability to utilize visible light as a clean and renewable energy source. Through unique radical-mediated pathways, photocatalytic strategies allow the selective activation of traditionally unreactive substrates, including haloarenes, alkanes, alcohols, carboxylic acids, and amines, thereby providing efficient routes to complex molecular architectures. Beyond organic synthesis, photocatalysis has also demonstrated significant potential in broader areas of applied chemistry. This review summarizes the major advances in photocatalytic C–C bond coupling reported from 2023 to early 2026, with special focus on C(sp³)–C(sp³), C(sp³)–C(sp²), and C(sp²)–C(sp²) bond-forming reactions. Representative catalytic systems, substrate scope, reaction mechanisms, and synthetic applications are critically discussed, including dual photoredox/transition-metal catalysis, metal-free photocatalysis, hydrogen atom transfer (HAT), proton-coupled electron transfer (PCET), radical–radical coupling, decarboxylative and deaminative functionalization, and enantioselective transformations. Finally, current challenges, emerging trends, and future opportunities for developing more sustainable, scalable, and selective photocatalytic C–C bond-forming methodologies are highlighted, providing a comprehensive resource for researchers working in synthetic and medicinal chemistry. Full article

During the service life of karst tunnels, groundwater containing Ca²⁺ and CO₃²⁻ can migrate along the shotcrete–surrounding rock interface and induce calcite deposition, thereby changing the interfacial material composition and load transfer path. To clarify the effect of this process on interfacial bonding performance, this study used molecular dynamics simulations to construct CSH–SiO₂, SiO₂–calcite, CSH–calcite, and CSH–calcite–SiO₂ interface models. The interfacial density distribution, radial distribution function, number of hydrogen bonds, interaction energy, and normal tensile failure behavior were analyzed. The results show that all four models reached stable energy plateaus after relaxation, and clear atomic density overlap and short-range RDF peaks appeared in the interfacial regions. These descriptors indicate short-range contact and possible Ca–O electrostatic attraction, hydroxyl-related hydrogen bonding, and carbonate-associated interactions between calcite and both SiO₂ and CSH surfaces. Approximately 80 hydrogen bonds were formed at the SiO₂–calcite interface, approximately 32 at the CSH–calcite interface, and approximately 59 in total for the two hydrogen bond subtypes at the SiO₂–CSH interface, indicating that the hydroxyl state of different substrate surfaces controls the interfacial hydrogen bond network. Interaction energy analysis shows that the single CSH–calcite interface has the strongest interaction (−51,753.6 kcal/mol), approximately 1.90 times that of the SiO₂–CSH interface and 16.43 times that of the SiO₂–calcite interface. However, in the three-layer composite model, the interaction energy on the CSH–calcite side is only approximately 28.0% of that on the SiO₂–calcite side, suggesting that a continuous calcite interlayer introduces asymmetric interfacial constraints. Tensile simulations further show that the SiO₂–calcite model has the highest peak stress (approximately 3.23 GPa) and exhibits brittle failure, whereas failure in CSH-containing systems is more likely to transfer into the CSH layer or weakly connected regions. These results indicate that calcite deposition does not simply strengthen or weaken the interface. Instead, within the two idealized endpoint configurations tested here, its effect depends on deposition continuity, the surface chemistry of the two substrates, and the weak links within the serial interface. This study provides a nanoscale theoretical basis for evaluating relative trends in the long-term service performance of shotcrete–surrounding rock interfaces, and for guiding future multiscale validations of drainage and waterproofing measures in karst tunnels. Full article

Background: Hepatocellular carcinoma (HCC) remains a leading cause of cancer mortality. The c-Met and VEGFR2 pathways synergistically drive HCC progression. Marine natural products offer chemically diverse drug reservoirs; however, conventional activity-guided isolation faces labor intensity, low throughput, and frequent compound rediscovery, limiting marine drug development. Objective: To pioneer an artificial intelligence-driven marine drug discovery workflow integrating deep learning virtual screening for identifying dual c-Met/VEGFR2 promising in silico candidate from marine natural product repositories. Methods: UniSite predicted binding pockets in c-Met (PDB: 4R1V) and VEGFR2 (PDB: 2XIR). Drug-likeness filtering of 695,000 compounds from COCONUT and CMNPD databases yielded 84,730 candidates. DiffDock-based screening identified dual-target binders, validated through 200 ns molecular dynamics simulations, MM-GBSA calculations, and DFT analyses. Results: The marine phthalide CMNPD30506 [(S)-3-ethyl-5,6-dihydroxyphthalide] emerged as the lead candidate, engaging VEGFR2 via four hydrophobic contacts and one π-cation interaction with LYS868, while binding c-Met through four hydrophobic interactions, two hydrogen bonds, and π-π stacking. Molecular dynamics demonstrated stable RMSD profiles and dynamic hydrogen bond enrichment. MM-GBSA revealed binding free energies of −14.79 and −13.28 kcal/mol for VEGFR2 and c-Met, respectively, driven by van der Waals forces. DFT calculations indicated a HOMO-LUMO gap of 2.410 eV. Conclusions: This AI-augmented workflow successfully identified CMNPD30506 as a promising dual c-Met/VEGFR2 HCC therapeutic from marine libraries, overcoming traditional discovery bottlenecks through integrated deep learning and physics-based simulations, exemplifying AI’s potential in marine pharmacological research. Full article

Graphene and graphene oxide (GO) are promising nanofillers for improving thermal transport in cementitious materials, but their performance is strongly affected by interactions with calcium silicate hydrate (C-S-H). Understanding how these fillers retain or lose their heat-transport capability after incorporation into the cement hydrate matrix is therefore important for rational nanocomposite design. Reverse non-equilibrium molecular dynamics simulations were conducted to compare isolated graphene/GO sheets with the corresponding sheets embedded in C-S-H. The extrapolated thermal conductivity of pristine graphene decreased from 1854.6 to 1264.2 W/(m·K) after embedding, giving a retention ratio of 0.68. Increasing the oxidation degree reduced the intrinsic conductivity of GO through defect-induced phonon scattering, while the additional reduction caused by C-S-H progressively weakened. At an oxidation degree of 20%, GO retained more than 90% of its isolated-sheet conductivity. Atomic heat-flux analysis showed that C-S-H markedly broadened the transport-direction distribution of graphene but produced only limited additional disturbance in GO. Interfacial binding energy increased with oxidation degree, and radial distribution function analysis identified short-range Ca-O coordination and hydrogen bonding at the GO/C-S-H interface. Phonon density of states analysis further revealed pronounced substrate-induced phonon softening in graphene, whereas the vibrational spectrum of GO remained comparatively stable. These results clarify the trade-off between intrinsic conductivity and matrix-induced thermal stability in graphene-based cementitious nanocomposites. Full article

Understanding the potential mechanisms of bacterial azo dye decolorization remains a challenge due to a limited understanding of the exact stereochemical forces guiding enzyme–substrate interactions. This study addresses these interactions by evaluating the in silico binding architectures of Orange G (OG) and Congo Red (CR) against the Bacillus-derived azoreductase model AzrA (PDB ID: 3W77). Computational modeling predicted favorable thermodynamic properties within the calculated active site, yielding binding energy scores of −8.17 kcal/mol for CR and −6.63 kcal/mol for OG. These simulations identified hydrogen-bonding and aromatic π-π interactions within the predicted binding pocket. These predictions suggest potential enzyme–dye association but do not demonstrate catalytic activity or azo-bond cleavage. Independently, Bacillus cereus BC WW Saida achieved an 81% decolorization of OG within 144 h and a 70% reduction in CR within 96 h. High-performance liquid chromatography (HPLC) indicated chemical transformation, demonstrating a significant decrease in primary dye peaks alongside the emergence of novel intermediate peaks at 254 nm. Rather than definitively establishing a metabolic pathway, these outcomes deliver preliminary structural models of azoreductase-substrate affinities, offering a useful framework for the comparative evaluation of microbial catalysts for industrial effluent purification. Full article

Population aging has made sarcopenia a growing concern in geriatric health. Protein–polyphenol non-covalent complexes can serve as carrier systems that improve the stability and bioactivity of natural antioxidants. This study refined the preparation parameters for the non-covalent complex of whey protein isolate (WPI) and resveratrol (RES), achieving protein digestibility of 83.60 ± 0.50% and DPPH scavenging of 52.41 ± 0.58% at pH 7.0, a WPI:RES molar ratio of 1:1, and a reaction time of 1.5 h. Relative to free WPI, the complex improved DPPH scavenging by 21.66% while preserving protein digestibility. The binding mode, interaction forces, and conformational evolution were investigated via spectroscopic experiments, docking studies and molecular dynamics simulations. RES selectively bound to the surface of β-lactoglobulin in WPI through hydrophobic interactions and hydrogen bonding, with a docking score of −6.366 kcal/mol and an MM-GBSA binding free energy of −30.48 kcal/mol. The complex maintained a highly stable conformation throughout the 100 ns molecular dynamics simulation. In conclusion, this study elucidated the structural changes of WPI upon non-covalent resveratrol binding. The WPI-RES complex exhibited enhanced DPPH radical scavenging activity while preserving protein digestibility, with potential implications for functional food development in sarcopenia management. Full article

To enhance the mechanical properties of carbon-fiber-reinforced polymer composites (CFRPs), this study devised a novel three-dimensional web-like “rigid–flexible” surface modification strategy. The synergistic incorporation of carbon nanotubes (CNTs), polydopamine (PDA), and cellulose nanofibers (CNFs) constructed a “three-dimensional nanospider web” modulus transition layer. The modified carbon-fiber (CF-0.1%CNT-PDA-CNF) surface exhibits a three-dimensional network structure, with significantly increased surface roughness. The surface energy increased by 128.60% compared to the desized carbon fiber, thereby improving the wettability of the carbon-fiber surface. The results of both PeakForce-Quantitative Nanomechanical Mapping (PF-QNM) and EDS analyses indicate that a transition layer of a certain thickness initially formed at the interface. At the interface, the modulus exhibits a gradual gradient decrease from carbon fiber to epoxy resin, achieving more efficient stress transfer. The interfacial shear strength (IFSS, 95.71 MPa), interlaminar shear strength (ILSS, 73.19 MPa), tensile strength (701.08 MPa), and flexural strength (934.41 MPa) of the CF-0.1%CNT-PDA-CNF/EP composite material increased by 38.39%, 54.93%, 51.74%, and 64.98%, respectively, compared to the composite material made from desized carbon fiber. Through hydrogen bonding, covalent bonding, and π-π interactions, CNTs, CNFs and PDA formed a “rigid–flexible” transition layer with a modulus gradient at the CF-epoxy interface, achieving a significant enhancement in the mechanical properties of the composite material. Full article

The extensive use of pesticides in modern agriculture has resulted in their persistent accumulation in environmental systems, posing significant risks to ecosystems and human health. Consequently, the development of integrated strategies for the sensitive detection and efficient removal of pesticide residues has become critically important. In this context, fluorescent inorganic–organic hybrid nanoparticles have emerged as versatile platforms owing to their tunable physicochemical properties and distinctive optical behavior. This review provides a comprehensive overview of recent advances in these hybrid nanomaterials for pesticide sensing and remediation. Particular emphasis is placed on the underlying photophysical mechanisms governing detection, including fluorescence quenching, Förster resonance energy transfer (FRET), inner filter effect (IFE), and photoinduced electron transfer (PET). In parallel, the role of interfacial interactions such as hydrogen bonding, electrostatic attraction, and π–π stacking in adsorption processes is critically discussed. Furthermore, these hybrid systems exhibit high adsorption capacities and rapid removal kinetics, enabling efficient pesticide elimination using both adsorption and catalytic degradation pathways. Overall, this review underscores the potential of fluorescent inorganic–organic hybrid nanoparticles as next-generation materials for sustainable environmental monitoring and remediation of pesticide contaminants. Full article

The main protease (MPro) of coronaviruses (CoVs) is an essential enzyme involved in viral replication and represents an attractive target for antiviral drug discovery. Based on the similar binding pocket residues within the MPro of different CoVs, this study aimed to identify potential inhibitors of SARS-CoV-2 MPro from PDB ID 6M2N using integrated computational approaches. Interaction-based pharmacophore modeling, virtual screening, molecular docking, MM-GBSA binding energy calculation, and molecular dynamics simulation (MDS) were performed using BIOVIA Discovery Studio. The validated pharmacophore model was utilized to screen the ZINC database, followed by docking and 100 ns MDS analyses of the top-ranked compounds. The pharmacophore model 01 demonstrated favorable predictive performance (AUC = 0.781). Virtual screening identified 483 compounds, from which 15 compounds were selected for docking studies. Among them, ZINC95473654 (Lig-1), ZINC95473725 (Lig-2), and ZINC08792368 (Lig-3) exhibited strong binding affinity toward MPro. Lig-1 demonstrated the best docking score and binding free energy, along with stable interactions with key catalytic residues HIS41, CYS145, and GLU166. MDS analyses further confirmed that Lig-1, Lig-2 and Lig-3 maintained stable conformations. The hydrogen bond distance monitoring and post MDS-MM-GBSA results suggest Lig-1 followed by Lig-3 as an inhibitor for MPro and persistent intermolecular interactions throughout the 100 ns simulation period. The findings suggest that Lig-1, followed by Lig-3, may serve as promising computational lead compounds targeting SARS-CoV-2 MPro, representing promising candidates for further experimental validation. Full article

Methane is an abundant carbon resource with significant potential for the sustainable production of hydrogen, syngas, light hydrocarbons, oxygenates, and carbon nanomaterials. However, its efficient utilization remains challenging because of the high stability of the C–H bond, requiring energy-intensive thermocatalytic processes that often suffer from limited selectivity, carbon deposition, and high CO₂ emissions. Plasma-assisted technologies have emerged as a promising alternative by activating methane through energetic electrons and reactive species under non-equilibrium conditions. Although considerable progress has been achieved, existing reviews have primarily focused on individual plasma sources, reaction pathways, or catalyst systems, with limited attention to the coupled interactions among plasma characteristics, radical chemistry, reactor engineering, and product selectivity. This review provides a comprehensive and critical analysis of plasma-assisted methane valorisation by integrating the fundamental mechanisms of electron-impact activation, radical generation, and plasma kinetics with reactor design and process performance. The major plasma reactor technologies, including dielectric barrier discharge, gliding arc, microwave, and plasma jet systems, are critically compared in terms of methane conversion pathways, energy efficiency, operating conditions, reactor configuration, and product distribution. Finally, current challenges and emerging opportunities, including plasma catalysis, advanced reactor architectures, operando diagnostics, and reactor scale-up, are discussed to provide future perspectives for the industrial implementation of plasma-assisted methane valorisation. Full article

Aqueous zinc-ion hybrid capacitors (ZIHCs) have attracted considerable attention for safe and sustainable energy storage; however, their practical application under variable temperature conditions remains challenging due to electrolyte freezing at low temperatures, accelerated water-related side reactions at elevated temperatures, and the instability of zinc electrode reactions. Herein, a diethylene glycol (DG)-based aqueous electrolyte was developed to improve the wide-temperature electrochemical performance of ZIHCs. The effects of different DG concentrations on electrolyte properties, molecular interactions, and electrochemical behavior were systematically investigated. The incorporation of an appropriate amount of DG regulates the hydrogen bond interactions among water molecules, thereby reducing water-related side reactions and improving zinc reversibility. Among the investigated electrolytes, the optimized DW80 electrolyte achieves balanced performance in terms of safety, low-temperature tolerance, and electrochemical stability. Benefiting from the optimized electrolyte composition, Zn||Zn symmetric cells exhibit stable long-term cycling performance, and the assembled ZIHCs demonstrate reliable operation over a wide temperature range from −40 to 60 °C. This work highlights the importance of optimizing cosolvent content and provides a simple strategy for improving the temperature adaptability of aqueous zinc-based energy storage systems. Full article

Polyphenol oxidase (PPO) is a key enzyme responsible for enzymatic browning in fresh-cut fruits and vegetables, severely compromising their quality and shelf life. This study aimed to investigate the combined inhibitory mechanism of oxyresveratrol (OXY) and epigallocatechin gallate (EGCG) on PPO through multi-spectroscopic analyses, molecular docking, TEM, and XRD, with the goal of developing a natural and effective anti-browning strategy for fresh-cut fruits. The results showed that the optimal combined effect was achieved at an OXY:EGCG ratio of 1:2, where the inhibition rate was significantly enhanced by 43.72% and 14.36% compared to using OXY or EGCG single treatment, respectively. The combined treatment exhibited enhanced chelation capacity of copper ion and DPPH radical scavenging activity, and enhanced hydrogen-bonding interactions while lowering binding energy, exhibiting characteristics of mixed inhibition kinetics. Structural characterization showed that the combined treatment drastically reduced the enzyme’s fluorescence intensity to 39.81% of that of the native enzyme, induced rearrangements in α-helix and random coil structures, triggered obvious protein aggregation, and weakened the intensity of crystal diffraction peaks. Importantly, the combined treatment effectively delayed browning in fresh-cut pear slices, demonstrating its practical application potential. These findings provide a promising natural combined approach for controlling enzymatic browning and extending the shelf life of fresh-cut produce. Full article

Decalin, accessible through the hydrogenation of coal-tar-derived naphthalene, is a saturated bicyclic hydrocarbon consisting of two fused cyclohexane rings, and provides a promising platform for high-energy-density fuel (HEDF) design. A systematic library of alkyl- and cycloalkyl-substituted trans-decalin derivatives was constructed to investigate structure–property relationships involving density, net heat of combustion (NHOC), specific impulse, viscosity, flash point, and thermal/oxidative stability. Minimum C–C and C–H bond dissociation enthalpies were used to comparatively assess thermal and oxidative stability by reflecting initial C–C homolysis and H abstraction tendencies, respectively. Density and volumetric NHOC were governed mainly by molecular compactness and packing efficiency, whereas gravimetric NHOC and specific impulse depended primarily on the H/C ratio and ring strain. The flash point was mainly associated with molecular mass, while viscosity was influenced by molecular mass and molecular architecture. Under the engineering-oriented constraints of viscosity ≤ 16 mPa·s and flash points ≥ 360 K, multi-objective screening identified the spiro four-membered-ring motif, particularly α-S-Cycle4, as providing the best overall property balance. In contrast, the fused three-membered-ring motif showed higher specific impulse but greater susceptibility to initial bond activation, suggesting its potential use as a blending component. This work provides quantitative structure-based guidelines for the rational design of HEDFs. Full article