Search Results (849)

The purpose of this work is to investigate the binding state of inorganic elements to flavonoid components in aqueous extract of Silybum marianum (SM) seeds, as well as the antioxidant activity of the extract. This study employed reversed-phase high-performance liquid chromatography (RP-HPLC) to separate silymarin flavonoids in boiling water decoction of SM seeds, and collected the post-column effluent in the segments according to the retention time of seven main silymarin flavonoid components. Inductively coupled plasma mass spectrometry (ICP-MS) was subsequently utilized to quantify nine inorganic elements (As, Cd, Co, Cr, Cu, Fe, Mn, Mo, Zn) in the collected HPLC fractions of the decoction. Meanwhile, electron paramagnetic resonance spectroscopy (EPR) was employed to assess the free radical scavenging activity of aqueous extract of SM seeds, using the signal intensity changes of 2,2-diphenyl-1-picrylhydrazyl (DPPH) and DMPO-OH• adducts as quantitative metrics. The results showed that essential trace elements (Cu, Fe, Mn, Zn) mainly existed as inorganic ions or strong polar forms in the tea-like infusion, with weak binding to flavonoid compounds. On the other hand, the aqueous extract exhibited significant •OH scavenging capacity, with a scavenging rate of 95% against •OH generated by continuous 5 min ultraviolet irradiation of H₂O₂ aqueous solution. This study provides experimental evidence for the development of SM as a food–medicine dual-purpose resource, proposing that consumption of SM seed tea represents a facile and effective approach to supplement trace elements and intake silymarin for enhancing endogenous antioxidant defense. Full article

Benzothiophene polymers, as a class of novel organic semiconductor materials, exhibit significant potential in the field of photocatalysis due to their broad light-responsive range and tunable energy level structures. In this study, a benzothiophene-based polymer organic semiconductor (denoted as P42) was integrated with titanium dioxide (TiO₂) via a simple sol–gel method, yielding an organic–inorganic hybrid material. This composite facilitates the modulation of energy level potentials and promotes the effective separation of photogenerated charges, thereby demonstrating remarkable synergistic catalytic performance in the photocatalytic oxidative coupling of benzylamines. By optimizing the ratio of organic to inorganic components and various photocatalytic reaction conditions, the hybrid material 1.7%P42-TiO₂, containing 1.7 wt% of the dithiophene polymer without any metal cocatalysts, exhibited outstanding performance under an air atmosphere and visible light irradiation after 12 h. It achieved a yield of over 88.7% and a selectivity exceeding 89.8% in the synthesis of N-benzoylaniline, significantly surpassing the performance of pure TiO₂ (52.9% yield, 54.9% selectivity) and P42 (54.4% yield, 54.9% selectivity). Structural and photophysical characterizations, including UV–Vis DRS, XRD, SEM, TEM, and EPR, reveal that the enhanced photocatalytic activity originates from broad visible-light absorption, improved charge separation, and well-matched energy levels. Mechanistic investigations suggest a synergistic pathway involving photoinduced hole oxidation and radical-mediated coupling. This work provides valuable insights and a reference for the solar-driven photocatalytic synthesis of nitrogen-containing platform molecules under mild conditions. Full article

Hyperspectral imaging (HSI) combined with chemometrics has emerged as a rapid and non-destructive technique for fruit quality evaluation, enabling efficient monitoring of biochemical changes during postharvest storage. Among quality indicators, antioxidant activity is closely associated with nutritional value and physiological stability. This study aimed to develop an HSI-based approach for assessing the antioxidant capacity of strawberries subjected to different pre-cooling treatments during storage. Strawberries were treated with five pre-cooling methods and stored for up to 41 days. Antioxidant activity was measured using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging assay. Hyperspectral data were collected and preprocessed using multiplicative scatter correction (MSC), followed by partial least squares regression (PLSR) to construct predictive models. Among the treatments, immersion vacuum cooling combined with one-cycle pulsing (IVCWP1) exhibited significantly higher DPPH scavenging activity (61.17 ± 12.31%) than immersion vacuum cooling with water (IVCW, 52.89 ± 18.30%) (p < 0.05). The PLSR model developed using MSC-corrected average reflectance spectra showed superior predictive performance and a higher coefficient of determination (R²) than models based on raw spectra. The results demonstrate that HSI coupled with chemometrics is an effective and practical tool for non-destructive evaluation of antioxidant activity and comparison of pre-cooling strategies in strawberries. Full article

By investigating the conditions for the C–C coupling reaction of p-terphenyls, we successfully synthesized C–C coupled dimeric p-terphenyls for the first time using a reaction system involving air, silica gel, and B(OH)₃. Additionally, we developed a novel method to synthesize furan-fused p-terphenyl dimers through solvent-free reactions by creatively applying rotary evaporation and heating. Compounds 6–12, 16, 20, and 22 demonstrated DPPH radical scavenging activity that was either stronger than or comparable to the positive control (vitamin C), with IC₅₀ values ranging from 0.14 to 4.61 μM. Compounds 4–22 also exhibited significant activity against α-glucosidase, with IC₅₀ values ranging from 0.37 to 17.9 μM, exceeding the efficacy of the positive control, acarbose. Moreover, compounds 6–14, 16–18, 21, and 22 demonstrated greater inhibitory activity against PTP1B compared with the positive control, oleanolic acid, with IC₅₀ values between 0.30 and 9.17 μM. These findings highlight their potential as promising leads or dietary supplements for the treatment and prevention of diabetes, as well as possible application as oxidative agents in food preservation. Full article

The valorization of agro-industrial by-products is a sustainable approach to recovering high-value bioactive compounds. In this study, Opuntia ficus-indica (L.) Mill. seed press residues were investigated as a source of phenolic and flavonoid compounds using microwave-assisted extraction (MAE). A multi-step optimization strategy was implemented, combining preliminary single-factor experiments (OVAT), response surface methodology based on a Box–Behnken design (BBD), and machine learning modeling using K-nearest neighbors coupled with the dragonfly algorithm (KNN_DA), followed by desirability-based validation. The effects of ethanol concentration (50–100%), microwave power (400–800 W), extraction time (2–4 min), and liquid-to-solid ratio (30–50 mL/g) were evaluated on Folin–Ciocalteu reducing capacity (FCRC), AlCl₃ complexation response, and antioxidant activity assessed by DPPH radical scavenging and reducing power assays. Optimal conditions were identified at 50% ethanol, 800 W microwave power, 4 min extraction time, and a liquid-to-solid ratio of 47.28 mL/g. Under these conditions, FCRC reached 376.85 ± 0.23 mg GAE/100 g DW and 49.16 ± 0.33 mg QE/100 g DW for AlCl₃ complexation response, with prediction errors of 2.80% and 0.82%, respectively. The optimized extracts exhibited enhanced antioxidant activity. These findings confirm MAE as a rapid and environmentally friendly technique and highlight the predictive performance of the KNN_DA model for process optimization. Full article

The changes in functional groups during in situ co-pyrolysis of tar-rich coal with wheat straw were systematically examined using synchrotron diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) coupled with thermogravimetric analysis (TGA). Dynamic changes in C=C, C-O, and C-O-C groups were monitored and assessed across 50–500 °C, complemented by thermogravimetric analysis to assess synergistic effects. It revealed that co-pyrolysis significantly alters the thermal cracking pathways of oxygenated structures, reducing the overall onset temperature by approximately 150 °C. Specifically, instead of maintaining thermal stability, co-pyrolysis promoted early structural aromatization and advanced the C=O decomposition onset by 50 °C compared to coal, achieving a remarkable functional group cleavage rate of 47%. Additionally, the C=C formation temperature was advanced by 150 °C. Furthermore, co-pyrolysis effectively suppressed the secondary structural transformations observed in biomass by limiting the relative accumulation of C–O–C structures to merely a 5% increase, compared to a 52% surge in wheat straw. Interestingly, while DRIFTS confirms facilitated localized bond cleavage and deoxygenation, TGA reveals a macroscopic negative synergy regarding overall weight loss. These findings provide profound insights into the complex radical interactions during co-conversion, offering a crucial theoretical basis for optimizing coal–biomass co-pyrolysis technologies. Full article

Non-thermal plasma-driven advanced oxidation is a promising method for treating organic wastewater, which exhibits rapid reaction kinetics and high pollutant removal and does not need chemical reagents. However, its practical application is often limited by high specific energy consumption and the inefficient mass transfer of short-lived reactive species across the gas–liquid interface. This review summarizes the fundamentals of non-thermal plasma chemistry and the process intensification of plasma multiphase reactors by mass transfer enhancement and waste energy-driven conversion. This review focus on four coupling approaches: microbubble-assisted plasma to expand the reactive interfacial area; plasma coupled with hydraulic cavitation to enhance convection and radical formation; plasma–piezoelectric catalysis coupling to harvest hydraulic energy and promote charge-driven reactions; and plasma-assisted Fenton oxidation to improve the utilization of weakly oxidizing species (H₂O₂). The energy efficiency of various plasma-based oxidation systems is compared and discussed clearly. Key remaining challenges are also discussed, including standardized energy efficiency assessment, scale-up and hydrodynamic control, catalyst stability and fouling, by-product formation and toxicity, and long-term operational reliability. Overall, this review aims to provide guidance for developing efficient plasma-based wastewater treatment systems for large-scale applications. Full article

In conventional low-viscosity solvents, magnetic field effects (MFEs) in photoredox catalysis are often negligible because photogenerated radical ion pairs (RIPs) diffuse apart before significant spin evolution occurs. This study reports using ionic liquids (ILs) as a tunable homogeneous “solvent cage” to observe distinct low-field MFEs in the phenothiazine-mediated photoinduced reductive dechlorination of aryl chlorides. Experimental results demonstrate that MFEs increase significantly with bulk viscosity, reaching saturation at approximately 1000 Gs with a maximum enhancement of about 15%, consistent with the hyperfine coupling mechanism (HFCM). Femtosecond transient absorption spectroscopy (fs-TA) reveals that the ionic liquid environment effectively reduces the radical cage escape rate, matching it with the spin evolution rate. This allows the external magnetic field to intervene in the back electron transfer (BET) process. However, unlike strongly confined micellar systems, the contribution of the triplet charge recombination (TCR) pathway here is moderate, intrinsically limiting the magnetic enhancement amplitude. These findings establish that MFE magnitude is determined by both viscosity-controlled cage dynamics and the efficiency of the TCR channel, providing a mechanistic basis for designing spin-modulated homogeneous photoredox systems. Full article

The ultraviolet (UV) copolymers of two monomers, one methacrylic and the other vinyl monomer (styrene, S) were prepared. As methacrylic monomers, citronellyl methacrylate (CM) or geranyl methacrylate (GM) were used. The preparation was proven to contain high solvent- and chemical-resistant copolymers due to their cross-linked structure with the conversion degree of the double bonds above 0.92 for poly(citronellyl methacrylate)/polystyrene (PCM/PS) and above 0.85 for poly(geranyl methacrylate)/polystyrene (PGM/PS) copolymers. The obtained copolymers showed only one glass transition temperature (T_g). Depending on the structure and amount of the used methacrylic monomer, the T_g values were from 0.4 °C to −15.2 °C for PCM/PS copolymers and from −23.2 °C to −50.5 °C for PGM/PS copolymers. The thermogravimetric analysis (TG/DTG) showed a higher thermal stability for PCM/PS (148–187 °C) than for PGM/PS copolymers (119–159 °C) in inert and oxidative atmospheres. The simultaneous thermogravimetric analysis coupled with Fourier Transform Infrared spectroscopy (TG/FTIR) showed that the pyrolysis and oxidative decomposition of the tested copolymers took place according to the radical mechanism. This led to receiving a mixture of low molecular mass organic molecules containing saturated and unsaturated fragments, carbonyl groups, aromatic fragments as well as to CO, CO₂ and H₂O. This indicated the depolymerization process (inert) and further oxidation processes of the initially formed volatiles and/or residues in oxidative conditions. Full article

Ensuring the simple, rapid, and real-time monitoring of the freshness of fresh food items is essential for maintaining food safety. By reacting with characteristic substances generated during spoilage, pH-responsive indicators can effectively reveal the degree of food freshness. In this study, a mixture of hydroxypropyltrimethyl ammonium chloride chitosan (HACC), polyvinyl alcohol (PVA), and blueberry anthocyanins (BAs) was adopted and, via an electrospinning strategy, changed into a membrane coupled with a pH-responsive ability to assess the freshness of shrimp. The results showed that HACC/PVA-BA membranes with a HACC: PVA ratio of 1:4 exhibited enhanced hydrophobicity, better WVP properties (4.32 × 10⁻⁹ g m⁻¹ s⁻¹ Pa⁻¹), a rapid pH-response ability within 5 s and super radical scavenging capacity (56.34% for DPPH and 54.74% for ABTS radicals). HACC’s immutable positive charge creates a strong electrostatic field that pre-concentrates spoilage-generated ammonia and intensifies the protonation state of BAs, which dramatically enhances colorimetric sensitivity and rapid response to volatile amines. Moreover, a satisfactory antibacterial ability for S. aureus and E. coli were also evidenced: HACC/PVA-BA (1:4) membranes achieved a maximum inhibition rate of 64.9% for E. coli and 62.2% for S. aureus. Once applied to monitor the freshness of shrimp stored at 4 °C, the HACC/PVA-BA (1:4) membranes were able to indicate shrimp freshness through visually recognizable color changes within 3 h, which correlated strongly with the spoilage indicators of total volatile basic nitrogen, total viable count, and pH value. It is suggested that the intelligent pH-responsive membranes show great potential for practical application in monitoring food freshness. Full article

The growing need for effective air pollution control technologies has prompted significant interest in innovative flue gas treatment methods. This study investigates the plasma–chemical mechanisms and pollutant abatement performance of a pilot-scale microwave-assisted plasma reactor operating at 915 MHz and up to 75 kW for simultaneous removal of sulfur dioxide (SO₂), nitrogen oxides (NO_x), and carbon dioxide (CO₂) from combustion flue gas. Plasma treatment induced radical-driven oxidation of nitric oxide (NO), substantially enhancing the aqueous solubility of nitrogen oxides and thereby improving ammonia scrubbing efficiency. However, excessive plasma power resulted in thermal NO_x formation, governed by local gas temperature, highlighting the critical need for optimized specific energy input. A logarithmic correlation between plasma power and NO_x concentration was derived, enabling estimation of power thresholds necessary to suppress thermal NO formation. Complete or near-complete SO₂ removal and high CO₂ capture efficiency (50–100%) were achieved, demonstrating the synergistic coupling of plasma activation with alkaline scrubbing. These findings demonstrate the viability of microwave-assisted plasma technology as a flexible and efficient solution for integrated flue gas pollutant control with potential for industrial-scale deployment in coal-fired power plants and other combustion facilities. Full article

This study presents a novel process intensification strategy for the degradation of tetracycline hydrochloride (TCH) by integrating the liquid detention phenomenon (LDP) into an ozone/peroxymonosulfate (O₃/PMS) system within a rotating packed bed (RPB). To address the inherent limitation of short liquid residence time in conventional high-gravity reactors, the introduction of a detained liquid volume (DLV) significantly prolonged the contact duration and enhanced the liquid holdup. Results indicated that an optimal DLV of 200 mL yielded remarkable improvements, boosting ozone absorption, TCH degradation, and COD removal efficiencies by 77.8%, 7.1%, and 75.0%, respectively, compared to the non-detention mode. Mechanistically, the presence of PMS not only complemented ozonation but was also effectively activated by ozone to generate a dual-radical system (·OH and SO₄·⁻), leading to deep mineralization of pollutants. Furthermore, a systematic investigation of operating parameters revealed a critical trade-off between mass transfer enhancement and residence time reduction. Overall, this work demonstrates that the RPB/O₃/PMS process coupled with liquid detention effectively overcomes mass-transfer and reaction-time bottlenecks, offering a promising, high-efficiency solution for the treatment of antibiotic-contaminated wastewater. Full article

Using norfloxacin (NOR) as the target pollutant, the synergism and degradation mechanism of ZnFe₂O₄-N-BC (MNBC), a nitrogen (N) and zinc ferrite (ZnFe₂O₄) co-doped biochar bifunctional catalyst (BC), in visible light (VIS)−peroxydisulfate (PDS) coupled system, were elucidated, and the synergistic mechanism was further supported by optical absorption and photo-induced charge transfer analyses. The results indicate that the degradation rate constant of the ZnFe₂O₄-N-BC/Vis-PDS system is 22.7 and 17.4 times higher than that of the ZnFe₂O₄-N-BC/Vis and ZnFe₂O₄-N-BC/PDS systems, respectively. More importantly, an apparent enhancement factor of 26.3% was obtained relative to the internal control systems. In addition, the coupled system showed a wider pH adaptation range. Furthermore, the radical quenching experiment and EPR analysis further revealed that multiple reactive species (including SO₄⁻, O₂⁻·, ·OH, h⁺, and ¹O₂) were involved in the degradation of NOR, and their relative contributions followed the order: ¹O₂ > SO₄⁻ > O₂⁻·> ·OH > h⁺. Finally, HPLC-MS analysis was performed to identify the key degradation intermediates of NOR, and thus to propose its possible transformation pathways. Full article

Closed-form analytic inverses allow explicit tracking of parameter effects, facilitate interpretation of experimental signals, and support solving inverse problems. Here, we derive a rigorous closed-form expression for the inverse Laplace transform of a class of shifted quasi-rational spectral functions with a square-root radical and a power-law decaying factor. These functions appear in coupled diffusion processes in physics and in the analysis of electromagnetic signal propagation through electrically cascaded networks, signal processing, and related areas. The transform is expressed as a finite sum of three generalized hypergeometric functions—two Kummer functions and one five-parameter Kampé de Fériet function—each multiplied by a monomial depending on the decay parameter. The validity of the result is confirmed by direct Laplace transformation, which recovers the original spectral function. Several known inverse transforms appear as limiting cases, illustrating the generality of the solution. Additionally, reduction formulas for a subclass of Kampé de Fériet functions demonstrate how the general solution encompasses previously known results and highlight the generality of the method. Full article

This study systematically investigates the role of Ni in Co₂SiO₄ in a bimetallic (Co²⁺,Ni²⁺)₂SiO₄ olivine-type system and the materials’ catalytic efficiency in a model Heck–Mizoroki coupling reaction. Thus, a series of olivines with varying (Co²⁺,Ni²⁺)₂SiO₄ compositions (0–100% Ni) was synthesised and characterised by ICP-OES, FTIR/Raman, P-XRD and XPS analysis. Ideal mixing of metals was achieved with (49:51) Co:Ni. Catalytic testing revealed distinct conversion vs. time profiles, with the (69:31) Co:Ni olivine exhibiting the best overall performance, combining good reactivity with near-perfect selectivity (>99%) and improved stability. Mechanistic pathways were probed through product scope analysis, reactant–product temporal profiling, leaching and radical scavenging experiments. Results suggest a radical-assisted Heck–Mizoroki mechanism. Spectroscopic data correlated Co²⁺ and Ni²⁺ incorporation with M1 and M2 site occupancy, where Ni²⁺ M2 sites enhanced reactant activation and intermediate stability and Co²⁺ in the M1 site enhanced product release, though also homocoupling in Co₂SiO₄. Minimal leaching was observed for all bimetallic catalysts. These findings highlight the tunability of bimetallic olivines for C–C coupling reactions via controlled cation distribution. Full article