Search Results (1,049)

Fresh lettuce is a key ingredient in ready-to-eat salads that are considered a valued dietary choice. Lettuce quality is strongly influenced by soil management practices, particularly in sustainable farming systems. This study evaluated the effects of three different soil disinfestation methods (flame weeding, microwave irradiation, and biological control (Trichoderma spp. inoculation) on the quality traits of Lactuca sativa L. var. Margò grown in a protected environment in southern Italy in a winter growth cycle. Minerals, nitrate content, colorimetric parameters, carotenoids, polyphenols, and antioxidant activity were assessed. The treatment with Trichoderma spp. significantly reduced nitrate accumulation (−21.3%) and increased some phenolic compounds and P (22%), while microwave irradiation treatment boosted total phenolic content by 44%. Flame weeding, although partially effective, was associated with a slight increase in carotenoids. Overall, microwave irradiation and Trichoderma spp. treatments emerged as the most promising options for balancing food safety and nutritional value. These findings offer valuable insights about the effect of soil disinfestation strategies on leafy vegetable quality. Full article

Chinese shale reservoirs are typically deep, clay-rich, and highly water-sensitive, which severely limits the effectiveness of conventional hydraulic fracturing. To address this challenge, we propose a microwave-assisted waterless fracturing method and investigate its feasibility through laboratory experiments on core samples from the Gulong shale and tight sandstone formations in the Daqing Oilfield. A coupled model integrating microwave power dissipation, pore water heating, and thermal stress evolution is developed to interpret the underlying mechanisms. Experimental results show that, under microwave irradiation (200 W, 40 s) and initial pore water content of 2.1–6%, fracturing is successfully induced without external fluid injection. The tensile failure of the rock coincides with the peak internal pore pressure generated by rapid vaporization and thermal expansion of pore water, as confirmed by a modified tensile strength measurement method. Fracture patterns observed in SEM and post-treatment imaging align with model predictions, demonstrating that microwave energy absorption by pore water is the primary driver of rock failure. The technique eliminates water-related formation damage and is inherently suitable for deep, water-sensitive reservoirs. This study provides experimental evidence and mechanistic insight supporting microwave-based waterless fracturing as a viable approach for challenging shale formations. Full article

The increasing demand for sustainable chemical processes has fostered the development of advanced catalytic systems for biomass valorization. In this work, a series of mono-, bi-, and trimetallic oxides (FeO, FeCuO, FeZnO, and FeCuZnO) were successfully synthesized using MIL-101-based MOFs as sacrificial templates. The obtained materials were thoroughly characterized by N₂ adsorption–desorption, XRD, FTIR, and TEM/STEM-EDX to investigate their structural, morphological, and textural properties. Their catalytic performance was evaluated in the selective oxidation of benzyl alcohol, a lignin-derived platform molecule, into benzaldehyde under microwave irradiation as a sustainable heating strategy. The results demonstrate that MOF-derived oxides exhibit superior activity compared to their parent MOFs, highlighting the beneficial effect of thermal treatment on the exposure of active sites. Among the catalysts, heterometallic oxides showed enhanced performance due to synergistic effects between metals. In particular, FeZnO reached a maximum yield of 62.1% towards benzaldehyde at 150 °C and 30 min, outperforming the monometallic oxide. Recycling tests revealed that FeZnO retained higher overall performance than FeCuO, which suffered from progressive copper leaching. These findings confirm the potential of MOF-derived multimetallic oxides as efficient and reusable heterogeneous catalysts for selective biomass-derived alcohol oxidation. The combination of microwave-assisted processes and the tuneable nature of MOF-derived oxides provides a promising pathway for designing sustainable catalytic systems with industrial relevance. Full article

Biodiesel is an alternative, sustainable, renewable, and environmentally friendly energy source, which has generated interest from the scientific community due to its low toxicity, rapid biodegradability, and zero carbon footprint. Biodiesel is a biofuel produced by the transesterification of triglycerides or the esterification of free fatty acids (FFA). Both reactions require catalysts with numerous active sites (basic, acidic, bifunctional, or enzymatic) for efficient biodiesel production. On the other hand, since the late 1990s, metal–organic frameworks (MOFs) have emerged as a new class of porous materials and have been successfully used in various fields due to their multiple properties. For this reason, MOFs have been used as heterogeneous catalysts or as a platform for designing active sites, thus improving stability and reusability. This literature review presents a comprehensive analysis of using MOFs as heterogeneous catalysts or supports for biodiesel production. The optimal parameters for transesterification/esterification are detailed, such as the alcohol/feedstock molar ratio, catalyst amount, reaction time and temperature, conversion percentage, biodiesel yield, fatty acid and water content, etc. Additionally, novel methodologies such as ultrasound and microwave irradiation for obtaining MOF-based catalysts are described. It is important to note that most studies have shown biodiesel yields >90% and multiple reuse cycles with minimal activity loss. The bibliographic analysis was conducted using the American Chemical Society (ACS) Scifinder^® database, the Elsevier B.V. Scopus^® database, and the Clarivate Analytics Web of Science^® database, under the institutional license of the Universidad Veracruzana. Keywords were searched for each section, generally limiting the document type to “reviews” and “journals,” and the language to English, and published between 2000 and 2025. Full article

A novel 4H-benzo[h]chromene derivative was efficiently synthesized and structurally characterized as a β-enaminonitrile. Single-crystal X-ray diffraction confirmed its molecular structure, revealing a stable crystal lattice stabilized by intermolecular N–H···N hydrogen bonds and π–π stacking. The compound was evaluated for its inhibitory activity against both wild-type EGFR (EGFR^WT) and the resistant T790M mutant (EGFR^T790M). It exhibited moderate activity against EGFR^WT (IC₅₀ = 3.27 ± 0.72 μM) but demonstrated significantly enhanced potency against EGFR^T790M (IC₅₀ = 1.92 ± 0.05 μM), showing a low resistance factor compared to the reference drugs Erlotinib and Gefitinib. Comparative molecular docking studies against both wild-type and T790M mutant structures suggested that the compound maintains a stable binding mode involving key interactions with the hinge region residue Met769, rationalizing its ability to circumvent the T790M resistance mechanism. These findings identify the 4H-benzo[h]chromene scaffold as a promising lead for developing novel inhibitors to overcome EGFR^T790M-mediated resistance. Full article

The phytopathogenic fungus Botrytis cinerea, which causes gray mold disease, has become a limiting factor on agricultural production. B. cinerea field control is made mainly using chemical fungicides, which has led to the spreading of resistant populations of this fungus. Thus, the quest of new fungicides molecules has been focused on synthesis of natural product-inspired compounds. The main aim of this work is to synthesize prenylated phenol derivatives and to assess their potential application as antifungal agents with minimal phytotoxic effects. Thus, new prenylphenols (4, 5, and 7) have been obtained by microwave irradiation with yields ranging from 2.4% to 42.9%, whereas compounds 8 and 9 were synthesized with yields of 25.6% and 54.1%, respectively. The effect of different concentrations of these compounds on B. cinerea spore germination, and their phytotoxic effect on tomato (Solanum lycopersicum L.) seed germination and root growth, were evaluated. Obtained results indicate that biological activities of all tested compounds are concentration-dependent. Interestingly, compound 7 exhibits the highest antifungal activity against B. cinerea spores (IC₅₀ < 50 µg/mL) with minimal phytotoxicity on tomato seed germination and root growth. In contrast, compounds 2 and 3 are active against spores (IC₅₀ = 461 and 325 µg/mL, respectively) but, at the same time, their phytotoxicity is important at the highest concentrations. These results indicated that the presence of hydroxyl and methyl substituents on the aromatic ring of these compounds induces variations in biological activities, and compound 7 could be a promising candidate as a sporicidal agent. Full article

There is a need to address the limitations of wheat straw (WS) as a raw biomass fuel, promote its valorisation into a high-quality renewable solid fuel, and enable this fuel to replace fossil fuels in applications such as power plants and industrial boilers. This study focused on optimizing microwave torrefaction parameters to enhance key fuel properties. Optimal conditions were determined via the Box–Behnken design (BBD) within Response Surface Methodology (RSM) as 422.32 W of microwave power, 14.95 min of irradiation time, and a 15 g microwave absorber, resulting in a 69.12% mass yield, an 18.44 MJ/kg higher heating value (HHV) surpassing lignite at 16.76 MJ/kg, and a 25.50% Energy-Mass Co-efficiency Index (EMCI). Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis/derivative thermogravimetric analysis (TG/DTG) were conducted to gain insights about chemical composition and thermal stability variations due to torrefaction. LCA showed that electricity produced from 1 ton of torrefied WS reduces CO₂ emissions by 259.26 kg CO₂eq compared to electricity generated from bituminous coal. From an economic perspective, the usage of torrefied WS for power generation lead to a net profit of CNY 435.19/ton. This scalable technology, by valorising agricultural waste for fuel production, delivers dual environmental and economic benefits, laying the groundwork for industrial deployment. Full article

Rubber material with high elasticity and viscoelasticity has become the most widely used universal material, and the study of the aging failure mechanism of rubber has been meaningful research in the polymer materials field. Cis-polyisoprene was employed to analyze the mechanism of oxidative degradation under artificial UV irradiation, and the GQDs/g-C₃N₄ photocatalysis with a 2D layered structure prepared by the method of microwave-assisted polymerization enabled to accelerate the degradation procedure. The results showed that the oxidation of cis-polyisoprene occurred during the irradiation for 3 days and the structure of cis-polyisoprene changed. The α-H of the double bond was attacked by oxygen to form hydroperoxide. Then, aldehydes and ketones generated as the addition reaction of double bonds occurred. The content of the hydrogen of C=C reduced, and the oxidative degradation was dominant at the initial aging stage. The crosslinking reaction was dominant at the final aging stage and the average molecular weight decreased from 15.49 × 10⁴ to 8.78 × 10⁴. The GQDs could promote the charge transfer and the photodegradation efficiency and inhibit the electron–hole recombination. The light capture ability of GQDs was improved after compositing with g-C₃N₄. The free radicals ·O₂²⁻ generated after adding GQDs/g-C₃N₄ nanoparticles, and the molecular weight of cis-polyisoprene decreased to 5.79 × 10⁴, with the photocatalytic efficiency increasing by 20%. This work provided academic bases and reference values for the application of photocatalysts in the field of natural rubber degradation and rubber wastewater treatment. Full article

Background/Objectives: Disinfection of removable prostheses is essential for controlling oral infections, yet the methods employed may compromise the mechanical reliability of denture base materials. This study evaluated the effect of microwave irradiation and immersion in 0.2% chlorhexidine solution on the fracture strength of three commonly used acrylic denture bases. Methods: Forty-five standardised maxillary palatal denture bases were fabricated from cross-linked conventional, high-impact, and light-cured acrylic resins. The specimens were divided equally into three treatment groups: water storage (control), immersion in 0.2% chlorhexidine solution for 30 min twice weekly, and microwave disinfection at 650 W for three minutes, each continued for four weeks. Fracture strength was determined by using the Universal testing machine. The data were analysed with one-way ANOVA followed by Bonferroni post hoc testing. Results: Cross-linked and high-impact acrylic resins exhibited significantly greater fracture strength than light-cured acrylics (p < 0.001). The overall ANOVA showed no statistically significant differences among disinfection methods (p = 0.069); however, post hoc comparisons revealed significant reductions in fracture strength within specific material groups following microwave disinfection. This effect was most pronounced in the light-cured group, whereas immersion in chlorhexidine produced no significant changes. Notably, the fracture strength of all groups remained above clinically acceptable thresholds. Conclusions: Microwave disinfection negatively influences the mechanical integrity of acrylic denture bases, particularly those fabricated from light-cured resins. In contrast, immersion in 0.2% chlorhexidine preserves fracture strength, supporting its use as a safe and effective protocol for routine disinfection in dental practice. Full article

Sustainable ultraviolet (UV) filters that couple photoprotection with antioxidant activity are needed. Carbon dots (CDots) derived from agro-industrial waste have emerged as promising candidates. CDots were prepared from Coffea canephora (coffee leaf) residues by a one-pot microwave route and characterized by UV–Vis, FTIR, and TEM. Antioxidant capacity was determined by CUPRAC and DPPH-EPR. The photoprotective efficacy was assessed in vitro by diffuse reflectance spectrophotometry before and after solar-simulator exposure. Nearly spherical CDots (3.3 ± 0.7 nm) displayed a 4.16 eV optical bandgap and broad absorption from 200 to 400 nm. At 10 μg mL⁻¹, CDots exhibited 24.62 ± 0.19% antioxidant activity relative to Trolox by CUPRAC, while by DPPH-EPR, they showed 99.9 ± 12.5% of radical quenching at 240 µg mL⁻¹. Addition of 4.5% w/w (dry basis) CDots to the sunscreen system increased the in vitro SPF from 26 ± 13 to 161 ± 8 (p < 0.05) while maintaining the critical wavelength at 380 ± 0.64 nm. After 30 min of irradiation, the SPF dropped only 10%, versus 44% for the CDots-free sample (control), indicating superior photostability. Coffee leaf CDots acted as an efficient broadband UV absorber and antioxidant that markedly enhanced and stabilized a conventional sunscreen formulation. The work positions waste-derived CDots as an eco-friendly, next-generation multifunctional ingredient, aligning with circular economy principles. Full article

In this work, we synthesized a small library of tricyclic compounds to assess whether they might have both anticancer and antiviral activity against three viruses that have recently caused epidemics. Concerning their anti-tumour activity, derivative 1 was found to be the compound with the highest GI₅₀ values on some cancer cell line panels. Particularly, in melanoma cell lines, its GI₅₀ values ranged between 1.54 μM (MALME-3M) and 2.03 μM (M14). Several derivatives with considerable anti-tumour activity showed antiviral activity as well, against influenza A virus (e.g., derivative 19, selectivity index of 21.36 in MDCK cells) or against Zika virus (compound 13, selectivity index of 20.20 in Huh-7 cells). Moreover, compounds 13 and 12 showed anti-SARS-CoV-2 activity, with selectivity indices of 150.00 and 63.63, respectively. Compound 1, for its anticancer activity, and 13, for its anti-SARS-CoV-2 activity, together with the compounds active against Zika virus and influenza A virus, are promising candidates for further studies. Full article

Microwave pretreatment (MWP) has emerged as a promising strategy to enhance the pyrolysis of lignocellulosic biomass due to its rapid, volumetric, and selective heating. By disrupting the recalcitrant structure of cellulose, hemicellulose, and lignin, MWP improves biomass deconstruction, increases carbohydrate accessibility, and enhances yields of bio-oil, syngas, and biochar. When combined with complementary pretreatments—such as alkali, acid, hydrothermal, ultrasonic, or ionic-liquid methods—MWP further reduces activation energies, facilitating more efficient saccharification and thermal conversion. This review systematically evaluates scientific progress in this field through bibliometric analysis, mapping research trends, evolution, and collaborative networks. Key research questions are addressed regarding the technical advantages of MWP, the physicochemical transformations induced in biomass, and associated environmental benefits. Findings indicate that microwave irradiation promotes hemicellulose depolymerization, reduces cellulose crystallinity, and weakens lignin–carbohydrate linkages, which facilitates subsequent thermal decomposition and contributes to improved pyrolysis efficiency and product quality. From an environmental perspective, MWP contributes to energy savings, mitigates greenhouse gas emissions, and supports the integration of renewable electricity in biomass conversion. Full article

4,4′-substituted-2,2′-((hexahydro-1H-benzo[d]imidazole-1,3(2H)-diyl)bis(methylene))bisphenols (1a–d) and 2,6-bis{[3-(2-hydroxy-5-substitutedbenzyl)octahydro-1H-benzimidazol-1-yl]methyl}-4-substitutedphenols (2a–b) were synthesized via microwave (MW) irradiation of aminal (2R,7R,11S,16S)-1,8,10,17-tetraazapentacyclo[8.8.1.1.^8,170.^2,70.^11,16]icosane 2 with p-substituted phenols. Microwave (MW) irradiation improved reaction rates and yields at 80 °C. Compounds 1a–d were racemic, and 2a–b were diastereomeric. NMR spectra revealed key signals for the perhydrobenzimidazole fragment, aromatic rings, and aminal carbons. Differences in the ¹³C NMR spectra highlighted structural variations, such as distinct carbonyl and methoxyl signals in 2d. MW irradiation at higher temperatures (100–120 °C) reduced yields of 1, especially for phenols with methyl (Me) and methoxy (OMe) groups, suggesting a shift toward the formation of compound 2. Additionally, higher temperatures led to polymerization byproducts, emphasizing the impact of MW energy on reaction pathways. These results provide valuable insights for designing molecules with potential applications in materials science and medicinal chemistry. Full article

Phycocyanin, a blue pigment from Arthrospira platensis, is widely used as a natural colorant in food products, but its application is limited by its sensitivity to light and temperature during extraction and storage. This study explored the impact of UV light on phycocyanin extracted from A. platensis using a microwave-assisted method. Water proved to be the most effective solvent, yielding the highest phycocyanin concentration and stability. The optimal extraction conditions to avoid phycocyanin degradation were identified as 45 °C and 100 W of microwave power. Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) analysis revealed increased chemical complexity at higher temperatures and identified biopterin–pentoside complexes, which enhanced phycocyanin stability during UV degradation. These findings provide new insights into the molecular mechanisms of interactions between phycocyanin and proteins, enhancing phycocyanin stability and functionality and thus providing food products with longer shelf lives by maintaining their nutritional and aesthetic qualities. Full article

Traditional synthetic methods, often limited by inefficiency, are increasingly being replaced by sustainable alternatives. This study presents a green approach combining microwave irradiation with in situ FTIR spectroscopy for real-time monitoring and optimising nitrogen-heterocycle synthesis, focusing on quinoxalines. Although both microwave-assisted synthesis and time-resolved FTIR are established techniques, their combined application remains underexplored, limiting their synergistic potential. The methodology was applied to synthesising 2,3-diphenylquinoxaline, a compound of interest in medicinal chemistry. Optimisation of the condensation between benzil and 1,2-phenylenediamine was achieved by exploiting the accelerated kinetics of microwave irradiation and continuous monitoring via in situ FTIR. Three catalytic systems were evaluated—hydrochloric acid (Brønsted acid), Montmorillonite K10 (heterogeneous catalyst), and molecular iodine (halogen/Lewis acid)—alongside a range of solvents, including ethanol, methanol, water, acetonitrile, ethyl acetate, dimethyl sulfoxide, and dichloromethane. Iodine proved to be the most efficient catalyst, while acetonitrile and ethyl acetate provided the most effective solvent systems. This integrated monitoring strategy reduces reliance on trial-and-error optimisation and establishes a streamlined, scalable, and efficient protocol. The dual-technique approach highlights a versatile pathway for advancing green synthetic methodologies with applications across the chemical and pharmaceutical industries. Full article