Frontiers in Chemistry最新文献

Organic micropollutants are still a major environmental and public health problem because they accumulate in all water source over the world. Because standard treatment is ineffective at the low concentrations at which these contaminants are present to remove, there is an urgent need to find better tertiary treatments for wastewater. The key points covered in this review are adsorption and Advanced Oxidation Processes (AOPs). The use of certain adsorption materials makes it possible to selectively sequestrate impurities, while in the case of AOPs destructive processes are performed by means of reactive radicals leading to mineralization of pollutants. These methods complement each other and provide both efficiency, waste reduction, and sustainability benefits-providing a synergy of their strengths. The AOP adsorption hybrids reported in this paper represent one of the emerging types of water-treatment units, which are particularly relevant given the high demand for improved tertiary treatment technologies capable of effectively removing persistent micropollutants from wastewater.

Graphene oxide (GO) nanosheets (0.5-2.0 phr) were incorporated into nitrile-butadiene rubber (NBR) to clarify how interfacial chemistry and dispersion control macroscopic performance. GO was synthesized by a modified Hummers method, and different filler concentrations of NBR/GO were prepared via solution-coagulation followed by sulfur vulcanization. Transmission electron microscopy (TEM) and atomic force microscopy (AFM) confirmed multilayer GO and best sheet dispersion at 1 phr, whereas 2 phr showed initial aggregation. Fourier-transform infrared spectroscopy (FTIR) confirmed that the NBR backbone and nitrile groups remained intact, while weak GO-derived C-O-C/C-O bands appeared at higher loadings. The C≡N band at ∼2,237 cm^-1 preserved its position but showed a slight increase in bandwidth, consistent with the formation of a hydrogen-bonded interphase. X-ray diffraction (XRD) showed loss of GO periodicity in the rubber matrix. UV-Vis/Tauc analysis indicated a non-monotonic band gap (direct 3.01→3.13→3.11 eV; indirect 2.84→2.92→2.96 eV), arising from confinement at well-dispersed loadings and π-π stacking at higher loadings. Dielectric measurements (10²-10⁶ Hz, 20 °C-100 °C) evidenced a more stable ε' for GO-filled samples, maximized at 1 phr. Mechanical testing showed simultaneous gains in tensile strength, tear resistance, and rebound elasticity at low GO loadings, while swelling and thermo-oxidative retention improved due to barrier effects and chain immobilization. Overall, ∼1 phr GO delivers the best structure-property balance, combining hydrogen-bond-mediated interfacial adhesion and optimal dispersion with stable dielectric behavior and reduced swelling/aging sensitivity; 2 phr yields the highest tensile value but also results in incipient aggregation and reduced dielectric stability.

Processing is the core traditional technology to regulate the efficacy of traditional Chinese medicine. Polysaccharides serve as key components in exerting biological activities such as immune regulation, antioxidant, and blood sugar reduction, its content and structural characteristics determine its biological activity, therefore, clarifying the mechanism by which processing affects the polysaccharides in traditional Chinese medicine is an important direction for explaining the processing of traditional Chinese medicine. In this paper, the main processing methods such as stir-frying, roasting and steaming are arranged and expounded in detail in terms of content, structure and activity. The results indicate that the processing affects the polysaccharide content through changing the physical properties of herbs, damaging cell structures, and triggering chemical reactions through multiple pathways. By breaking glycosidic bonds under the action of heat, acid and water, the changes of molecular weight, monosaccharide composition, functional group ratio and the spatial structure of polysaccharide were changed, thus affecting the biological activities of polysaccharide such as immunity and antioxidation. The existing research shows that the effect of processing on traditional Chinese medicine polysaccharide has the specificity of "process-medicine-component", in the future, modern analytical techniques such as X-ray diffraction and high-resolution mass spectrometry should be combined to deeply analyze the molecular mechanism of regulating the structure-activity relationship of polysaccharides in processing, so as to provide scientific basis for the standardization and accurate optimization of processing technology of traditional Chinese medicine.

Covalent Organic Frameworks (COFs) are popular photocatalysts that utilize solar energy to generate hydrogen peroxide and evolve hydrogen because of their intrinsic porosity, robust framework, and excellent structural regularity. Benzothiadiazole-based donor-acceptor type COFs, PC-NB and PC-NPB, having distinct $\pi$ -bridges, influence electron transport and photocatalytic efficiency. Using degree-based topological indices and their entropy analysis, this study attempts to theoretically investigate the covalent organic frameworks PC-NB and PC-NPB to evaluate the structural complexity and stability. By offering an organized method for analyzing molecular graph features, edge partition facilitates the computation of topological indices. The calculated topological indices of the COFs are compared in detail and presented graphically. PC-NPB consistently shows higher values across nearly all degree-based topological indices, suggesting that it has a more connected structure. Additionally, lower entropy values in PC-NB indicate a higher degree of topological regularity and symmetry, which are traits frequently associated with enhanced rigidity, crystallinity, and thermodynamic stability.

Introduction: A new class of spiroisoxazolines was efficiently synthesized through a regioselective cycloaddition between arylidene tetralone 1 and arylnitrile oxides 2, characterized and assessed for their in vitro antimicrobial activity.

Methods: The structures and regioselectivity of the obtained cycloadducts were confirmed by 1H, 13C-NMR, IR, elemental analysis, and mass spectrometry, and further supported by theoretical calculations that explained the reaction process and the regioselective results. The antimicrobial profile of the synthetized spiro derivatives was evaluated against the yeast Candida albicans, the Gram-postive bacteria (Staphylococcus aureus and Bacillus subtilis), and the Gram-negative bacteria (Escherichia coli and Pectobacterium basiliensis). In addition, in silico studies were carried out to rationalize the experimental findings and provide mechanistic insight.

Results and discussion: Two spiroisoxazolines, defined as 3b and c, showed notable antimicrobial activity, producing inhibition zones between 8.33 ± 0.57 and 14.00 ± 2.00 mm. Compound 3b was active against all tested strains and demonstrated ampicillin-comparable MIC values of 10 μg/mL against E. coli, P. brasiliensis, and B. subtilis. It showed moderate to weak activity against S. aureus (90 μg/mL) and C. albicans (300 μg/mL). Compound 3c displayed selective activity toward Gram-positive bacteria with MIC values of 50 and 500 μg/mL against B. subtilis and S. aureus, respectively. Molecular docking studies confirmed the high binding affinities of 3b and 3c toward the active sites of the targeted proteins, in agreement with the antimicrobial results. POM analyses further indicated the coexistence of antifungal (O1δ--O2δ-) and antiviral (O1δ--N1δ-) pharmacophoric sites, although steric constraints introduced by two methyl substituents may limit their optimal interaction. The calculations also confirmed favorable bioavailability and the absence of predicted toxicity for all compounds. Overall, this combined experimental -theoretical study highlights the mechanistic basis and biological relevance of these spiroisoxazolines, underscoring their potential as promising scaffolds for the rational design of antiviral drug candidates.

Janus transition-metal dichalcogenide (TMD) heterostructures offer unique opportunities for coupling mechanical flexibility with catalytic functionality. Molecular dynamics simulations reveal that in-plane SMoSe-XS₂ (X = Mo, W) heterostructures spontaneously form sinusoidal superlattices driven by interfacial asymmetry, exhibiting over fivefold enhancement in fracture strain and pronounced size-dependent strength. The periodic profile of Armchair and Zigzag configurations highlights the intrinsic link between structure and mechanical response. Density functional theory calculations further demonstrate that the wrinkled interfaces significantly improve hydrogen evolution reaction (HER) activity, with Gibbs free energies as low as -0.18 eV, resulting from the upward shift of the Se and S p-band centers near the Fermi level, facilitating optimal H adsorption. This work establishes Janus TMD heterostructure superlattices as promising candidates for multifunctional applications integrating mechanical adaptability and catalytic efficiency.

Resveratrol (RES), a polyphenol with notable therapeutic potential, faces clinical limitations due to poor water solubility and low bioavailability. This study aimed to enhance the solubility and stability of RES by forming inclusion complexes with hydroxypropyl-β-cyclodextrin (HP-β-CD) using three drying methods: spray drying (SD), freeze-drying (FD), and solvent evaporation (SE). Phase solubility analysis confirmed the successful formation of a stable complex (K = 5278 M^-1) at an optimal 1:2 RES: HP-β-CD ratio. Among the dried products, the spray-dried complex (RHSD) demonstrated superior performance in moisture content, yield, and resveratrol content. It achieved the highest solubility enhancement (89-fold increase). In contrast, the freeze-dried complex (RHFD) showed the most potent antioxidant activity (IC₅₀ = 14.01 μg/mL). Physicochemical characterization via FTIR confirmed the formation of the inclusion complex. At the same time, XRD and SEM analyses revealed that RHSD possessed an amorphous structure, whereas RHFD and RHSE exhibited semi-crystalline characteristics. Subsequent drug-release studies demonstrated that RHSD followed non-Fickian release kinetics, unlike the diffusion-controlled release of RHFD and RHSE. These findings demonstrate that spray drying produces complexes with optimal physicochemical properties for solubility and dissolution, while freeze drying better preserves antioxidant activity, providing crucial insights for developing resveratrol-cyclodextrin formulations in pharmaceutical applications.

The electrocatalytic reduction of CO₂ (CO₂RR) powered by renewable energy offers a promising strategy to mitigate climate change while generating valuable fuels and chemicals. Achieving high performance in this process strongly depends on the properties of the electrode materials and the overall electrode architecture. In this context, nanocarbon materials, generally used as supports, are far from being inert; they can actively influence CO₂RR by stabilising adsorbed intermediates and directing reaction pathways through their hydrophobicity, porosity and defective structure. Unlike most reviews that focus exclusively on the active metal phase, this mini-review highlights the emerging dual role of nanocarbons (acting both as substrates and as active components) in determining catalytic activity and selectivity. It summarises recent advances in CO₂RR using nanocarbon-based materials, including both metal-free and hybrid systems, and discusses how doping and interfacial engineering enhance CO₂ activation, product selectivity and process efficiency. Gas-diffusion electrodes incorporating nanocarbon architectures improve mass transport and triple-phase boundary formation (gas-solid-liquid interface), enabling high current densities and multi-carbon product generation. These aspects demonstrate that tuning nanocarbon properties is essential for developing efficient and scalable CO₂RR electrodes, thereby advancing sustainable carbon utilisation technologies.

Dissolved gas analysis (DGA) in insulating oil can achieve early warning of local discharge, overheating or arc failure in transformers. It can also quantitatively evaluate the aging degree of insulating equipment, providing a basis for formulating predictive maintenance strategies, so as to improve the reliability of power grid power supply. At present, the existing common offline detection methods take a long time, and the dissolved gases in transformers are usually flammable and explosive, posing potential hazards to on-site maintenance personnel. Therefore, it is urgent to develop online detection methods for DGA. This article introduces the types and milestone research progress of DGA online detection methods in recent years (2019-2025). The instant sensing methods of dissolved gas in transformer oil are summarized and analyzed, including on-line gas chromatography analysis system, spectral analysis, and gas sensor methods. Through summarizing the advantages of different methods in terms of detection limit, response speed, operation and maintenance cost, etc., it puts forward the development trend of promoting intelligent and accurate power equipment status monitoring. This review aims to promote the further development of on-line DGA and contribute to the construction of an intelligent grid protection system by providing important technical insights.