Heterocycles are an important class of compounds that are extensively used in pharmaceutical and industrial applications. The quest for efficient and sustainable approaches for such valuable molecules under green conditions has led to the exploration of various heterogeneous catalysts. Among these, graphitic carbon nitride (g-C3N4) functionalized with active Lewis-Brønsted acid sites stands out as an attractive candidate owing to its tailor-made characteristics. Hence, this review provides a comprehensive and systematic analysis on the design and utility of acidic functionalized g-C3N4 materials as novel carbonaceous catalysts for the chemical/photochemical establishment of numerous bioactive heterocyclic scaffolds and furanic derivatives. Several key synthetic strategies (protonation, immobilization of heteropolyacids/organic acids, sulfonation, sulfonation-metal doping, acid group/ionic liquid grafting, or hybridization with biochar/polymeric ionic liquids) along with catalyst characterization/performance/reusability and reaction optimizations for such transformations are elaborated. Last but not least, perspectives and challenges in the application of these promising hybrid nanomaterials are presented.
The study evaluated the changes in nutritional, physicochemical, and chemical components of durian (Durio zibethinus) white peel flour at different drying temperatures (45-55 degrees C) using convective drying, heat pump drying, and freeze-drying methods. The results revealed that a drying temperature of 50 degrees C was optimal among the three drying techniques, with total polyphenol, flavonoid, 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging, 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS+) radical scavenging, and Ferric Reducing Antioxidant Power (FRAP) values of 714.65 mg GAE/100 g DM, 40.67 mg QE/100 g DM, 226.96 mg AAE/100 g DM, 593.51 mg AAE/100 g DM, and 553.66 mg Fe2+/100 g DM, respectively. Scanning electron microscopy showed that the flour particles aggregated into clusters, whereas Fourier-transform infrared spectroscopy (FT-IR) results evidenced the existence of -OH and -C=O characteristic chemical groups. The flour exhibited antibacterial activity against Staphylococcus aureus and Campylobacter jejuni. A Pearson association indicated a direct relationship between the chemical composition and the bioactive properties.
Engineering materials that are simultaneously highly conductive and electrochemically robust is a persistent challenge. This work demonstrates a successful strategy to decouple these competing properties in antimony-doped tin oxide (SnO2:Sb, ATO) thin films prepared via a sol-gel method. Systematic Sb-doping enhances electrical conductivity by over 3 orders of magnitude, with only a minimal 5% trade-off in corrosion resistance. A comprehensive X-ray diffraction analysis with Rietveld refinement reveals the microstructural origin of this behavior: Sb acts as a dual-role agent, simultaneously promoting crystallization (reducing the amorphous content from 39.1% to 17.1%) and inhibiting grain growth (reducing the crystallite size from 65.4 to 41.4 nm). This structural analysis also experimentally validates major first-principles Density Functional Theory (DFT) predictions, such as significant lattice expansion. The DFT simulations rationalize the decoupled properties, revealing that Sb induces bulk metallization while increasing the surface's intrinsic nobility (work function). The study concludes that the performance is governed by these quantified microstructural changes, offering a validated pathway for designing multifunctional electrodes.
Cultured lichen mycobionts have been considered as valuable sources of natural compounds with unique structure scaffolds. Nigrovothelium inspersotropicum, a crustose lichen from the family Trypetheliaceae, is an indigenous species in Vietnam. However, there is a scarcity of chemical and biological information available regarding N. inspersotropicum and its cultured mycobionts. In this study, the mycobiont of N. inspersotropicum was cultivated and subjected to chemical and biological investigations. As a result, six compounds, including 3,4-dihydro-7,8-dihydroxy-6-methoxy-3-methylisocoumarin (1), (+)-(3S)-6,7-dimethoxymellein (2), 8-hydroxy-6,7-dimethoxyisocoumarin (3), aspermytin A (4), subnudatone B (5), and beta-sitosterol (6), were isolated and structurally elucidated using extensive spectroscopic analyses (1D-and 2D-NMR and HRESIMS). Notably, compound 1 is new compound, while compound 2 is identified as a new natural compound. The isolated compounds were evaluated for their inhibitory activities against alpha-glucosidase, nitric oxide production, SARS-CoV-2 Mpro, and HIV-1 reverse transcriptase. In summary, this study presents new information on natural compounds derived from the mycobiont of N. inspersotropicum and their promising anti-inflammatory, antihyperglycemic, and antiviral activities.
This study developed a 1D compartment model with 21 continuous stirred tank reactors to evaluate NH3 co-firing (0%-30%) with bituminous coal (BC) and Ninh Binh anthracite (NB) in a 500 MWe pulverized coal (PC) combustor, advancing low-emission power generation for using Vietnam's coal resources. The model employs 341 reactions, including 117 nitrogen-related, and accurately predicts combustion performance and emissions. Without NH3 co-firing, BC and NB show comparable combustion, with NB's higher fixed carbon (61.8 wt.% vs. 54.7 wt.%) driving faster heat release. At 10% NH3, NOx emissions remain stable (123.6-126.5 ppm vs. 122.3-125.5 ppm at 0%), the pathway favouring N2O conversion to N2. At 30% NH3, NOx increases significantly (639.8 ppm for BC, 565.7 ppm for NB) due to the NH3 -> NH2 -> HNO -> NO pathway, amplified by the BC's higher volatile matter (29.5 wt.% vs. 13.3 wt.%). CO2 emissions decrease by 28.2% for BC and 28.0% for NB, leveraged by NH3's carbon-free nature. However, increased NOx emissions at 30% NH3 indicate trade-offs which require further investigation. This model can be used for evaluating NH3 co-firing ratios in industrial-scale combustors, balancing NOx control and CO2 reduction while elucidating emission formation pathways.
