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Zinc oxide (ZnO)-based varistor ceramics, incorporating varying amounts of Y2O3/CeO2, were fabricated through a twostep solid-state reaction method involving pre-calcination and subsequent sintering processes. ZnO powder and corresponding additives served as raw materials in the production. The investigation of phase composition, microstructure, and electrical properties employed techniques such as X-ray diffractometry (XRD), scanning electron microscopy (SEM), and direct current electrical measurement. The findings revealed that varistor ceramics sintered at 950°C, using powder pre-calcined at 800°C and doped with an appropriate amount of Y2O3, exhibited enhanced electrical properties. Conversely, the introduction of varying concentrations of CeO2 did not contribute to the improvement of the electrical characteristics. The CeO2-doped samples displayed lower breakdown voltages and nonlinear coefficients compared to the undoped sample (M0). The addition of Y2O3 proved effective in improving the nonlinear coefficient but resulted in a decrease in the breakdown voltage withstand capability of the samples. A Y2O3 content of 0.5% was identified as a suitable compromise, balancing both factors. Notably, ZnO varistors doped with 0.5 mol% Y2O3 demonstrated optimal comprehensive electrical properties, featuring a breakdown field of 620 V/mm and a nonlinear coefficient of 45. These results suggest that Y2O3 doping holds promise as a viable strategy for achieving varistor ceramics with outstanding electrical performance.

During curcumin production in Vietnam, curcumin-removed turmeric oleoresin (CRTO) has been considered as a by-product. It costs to treat the by-product to prevent environmental pollution. In this study, the by-product was utilized as an active ingredient for preparing a botanical fungicide-based nano-emulsion and evaluated for its in vitro and in vivo control efficacy against Colletotrichum gloeosporioides, a causal agent of anthracnose of litchi, in the laboratory as well as a field trial. The nano-emulsion is colloidally stable and uniform with particle sizes of 95–250 nm. CRTO nano-emulsion significantly affected various Colletotrichum species. Notably, this nano-emulsion showed potent inhibition for the mycelial growth of C. gloeosporioides and solidly suppressed the development of anthracnose on litchi fruits. In the in vitro inhibition test, the equivalent half-maximal inhibitory concentration of CRTO in nano-formulation was 0.11 mg·mL−1, which was 3.0× and 6.1× lower than IC50 values of CRTO alone (0.33 mg·mL−1) and a mixture of curcuminoids (0.48 mg·mL−1), respectively. In the field trial, the litchi anthracnose infection was effectively controlled by nano-formulation. These results suggest that CRTO nano-emulsion could be used as an alternative to harmful synthetic fungicides to control anthracnose on litchi fruits.

Building upon prior research demonstrating the excellent antifungal and nematicidal efficacy of Annona squamosa Lin. seed extracts, this study extends its scope to investigate similar properties in seed extracts from two other Annonaceae species: Annona muricata Lin. and Annona glabra Lin. The focus is on assessing their effectiveness against tomato late blight (TLB) and wheat leaf rust (WLR) diseases, as well as their broader antifungal activity against Colletotrichum sp. and Fusarium sp. The A. glabra seed extract exerted a superior control efficacy against TLB (85 % at 62.5 μg/mL) and WLR (75 % at 125 μg/mL) in vivo. The two Annonaceous extracts also exhibited in vitro antifungal inhibition against Colletotrichum sp. and Fusarium sp., as well as toxicology against pine wilt nematodes and Artemia salina. Besides, they showed phytotoxicity against Raphanus sativus seed germination. Squamocin G, a potent bioactive acetogenin, was isolated from A. glabara, which was found to occur at high contents in the following ascending order in A. glabra, A. muricata and A. squamosa dichloromethane extracts. To investigate the antifungal mechanism, molecular docking and molecular dynamic of squamocin G ligand were also performed for the first time at the active site of succinate dehydrogenase and β‐tubulin. [ABSTRACT FROM AUTHOR]

From the aerial parts of Eupatorium fortunei, four thymol derivatives (1-4) were isolated and structurally elucidated by NMR and mass spectroscopic methods. Of which, a new dimeric thymol derivative (1) was characterized and its absolute configuration was established by electronic circular dichroism quantum method. In addition, the 1D and 2D NMR as well as HR-ESI mass spectral data of 2 were provided for the first time. Compounds 2-4 were evaluated for their inhibitory activity against α-glucosidase and acetylcholinesterase enzymes. All tested compounds showed weak inhibition at the concentration range of 1–256 μg/mL in both enzymatic assays. [ABSTRACT FROM AUTHOR]

Anthracnose in citrus is a severe disease caused by Colletotrichum species. Synthetic fungicides have been used to combat this citrus disease; however, they may have adverse health effects on humans and cause harmful environmental impacts. During a search for environmentally friendly fungicides, we successfully prepared organic copper (copper (II) oleate) nanoparticles by using natural chitosan polymer as a coating agent and stabilizer and by combining an exchange reaction and in situ coating method. Organic copper nanoparticles coated with chitosan polymer (Cu‐oleate@CS NPs) with Cu contents ranged from 5.0 to 6.0 % by weight. The nanoparticles have an average particle size ranging from 50 nm to 60 nm (TEM), covered by a layer of polymer with a thickness of about 10 to 12 nm. The analytical results of zeta potential and dynamic solution size showed that the nanoparticles are uniformly dispersed (90–120 nm by DLS), with high stability (zeta potential=−61.7 mV) and low cytoxicity to Vero healthy cell line. Cu‐oleate@CS NPs significantly inhibited the mycelial growth of C. gloeosporioides in vitro at 500 and 1000 μg/mL. In field trials, the best antifungal efficacy of Cu‐oleate@CS NPs against citrus anthracnose on orange plants was found at a spray concentration of 0.33 % with a disease control efficacy of 54.18 % at 14 days after the second spraying. Our study results demonstrated a novel preparation of Cu‐oleate@CS NPs and suggested that it could be used as a promising nanoformulation to control citrus anthracnose in vitro and in vivo. [ABSTRACT FROM AUTHOR]