Mcneilltran2185

Electrochemical carbon dioxide reduction reaction (CO2 RR) represents a promising way to generate fuels and chemical feedstock sustainably. Recently, studies have shown that two-dimensional metal carbides and nitrides (MXenes) can be promising CO2 RR electrocatalysts due to the alternating -C and -H coordination with intermediates that decouples scaling relations seen on transition metal catalysts. However, further by tuning the electronic and surface structure of MXenes it should still be possible to reach higher turnover number and selectivities. To this end, defect engineering of MXenes for electrochemical CO2 RR has not been investigated to date. In this work, first-principles modelling simulations are employed to systematically investigate CO2 RR on M2 XO2 -type MXenes with transition metal and carbon/nitrogen vacancies. We found that the -C-coordinated intermediates take the form of fragments (e. g., *COOH, *CHO) whereas the -H-coordinated intermediates form a complete molecule (e. g., *HCOOH, *H2 CO). Interestingly, the fragment-type intermediates become more strongly bound when transition-metal vacancies are present on most MXenes, while the molecule-type intermediates are largely unaffected, allowing the CO2 RR overpotential to be tuned. The most promising defective MXene is Hf2 NO2 containing Hf vacancies, with a low overpotential of 0.45 V. More importantly, through electronic structure analysis it could be observed that the Fermi level of the MXene changes significantly in the presence of vacancies, indicating that the Fermi level shift can be used as an ideal descriptor to rapidly predict the catalytic performance of defective MXenes. Such an evaluation strategy is applicable to other catalysts beyond MXenes, which could enhance high throughput screening efforts for accelerated catalyst discovery.In photocatalysis, the Schottky barrier in metal-semiconductor hybrids is known to promote charge separation, but a core-shell structure always leads to a charge build-up and eventually shuts off the photocurrent. Here, we show that Au-Cu2 O hybrid nanostructures can be continuously tuned, particularly when the Cu2 O domains are single-crystalline. check details This is in contrast to the conventional systems, where the hybrid configuration is mainly determined by the choice of materials. The distal separation of the Au-Cu2 O domains in Janus nanostructures leads to enhanced charge separation and a large improvement of the photocurrent. The activity of the Au-Cu2 O Janus structures is 5 times higher than that of the core-shell structure, and 10 times higher than that of the neat Cu2 O nanocubes. The continuous structural tuning allows to study the structure-property relationship and an optimization of the photocatalytic performance.

This study investigated three in vitro models to assist in elucidating possible mode-of-action, which could be adopted to evaluate insecticidal activity of complex, unknown, or multi-constituent formulations. We used a combination of absorbance spectrometry, confocal scanning laser microscopy and microelectrode ion flux estimation (MIFE) to provide insight into potential target sites for insecticides. This study used two insect cell lines and evaluated three pyrethroid insecticides.

We observed that the two cell lines produced distinctly different responses. Drosophila melanogaster D.mel-S2 cell line was a useful model to monitor ion flux changes, resulting from insecticides with neural toxicity; however, it was less useful to determine some metabolic pathway indicators of toxic stress. Conversely, the Spodoptera frugiperda Sf9 cell line produced acute reactive oxygen species (ROS) in response to insecticide treatments, but was not highly responsive in electrophysiological experiments. We also showed thaty to be unknown.Cisplatin is a first-line drug in clinical cancer treatment but its efficacy is often hindered by chemoresistance in cancer cells. Reduced intracellular drug accumulation is revealed to be a major mechanism of cisplatin resistance. Nanoscale drug delivery systems could help to overcome this problem because of their more active cellular uptake and more accurate tumor localization. DNA nanostructures have emerged as promising drug delivery systems because of their intrinsic biocompatibility and structural programmability. Herein, three diverse DNA nanostructures are constructed and their potential for cisplatin prodrug delivery is investigated. Results found that these DNA nanostructures could remarkably enhance the cellular internalization of platinum drugs and thus increase the anticancer activity, not only to regular lung cancer cells (A549), but more importantly to cisplatin-resistant cancer cells (A549cisR). Further, in vivo studies also demonstrate that cisplatin prodrug loaded DNA nanostructures could effectively suppress tumor growth in both regular and cisplatin-resistant tumor models. This study suggests that DNA nanostructures are effective carriers for platinum prodrug delivery to combat chemoresistance.

In order to discover natural-product-based pesticidal candidates, a series of coumarin-like derivatives containing oxime ester fragments at the C-8 position were prepared by structural modification of osthole, a natural plant product isolated from Cnidium monnieri. Their pesticidal activities were evaluated against two typically fruit trees/crop-threatening agricultural pests, Mythimna separata Walker and Tetranychus cinnabarinus Boisduval.

Osthole was regioselectively oxidized by selenium dioxide to give the E-isomer, (2'E)-3'-formaldehydylosthole (2). Four key steric structures of 2, (2'E, 4'E)-(o-chloropyrid-3-ylcarbonyl)oximinylosthole (4o), (2'E, 4'E)-(styrylcarbonyl)oximinylosthole (4t), and (2'E, 4'E)-(acetyl)oximinylosthole (4w) were undoubtedly confirmed by X-ray crystallography. Against T. cinnabarinus, it is noteworthy that (2'E, 4'E)-(p-chlorophenylcarbonyl)oximinylosthole (4c) exhibited over three-fold more potent acaricidal activity of the precursor osthole, with especially good control efficiency observed in the glasshouse. Against M. separata, compounds 4c and (2'E, 4'E)-(p-nitrophenylcarbonyl)oximinylosthole (4f) showed the most pronounced growth inhibitory activity. The relationships between their structures and agricultural activities also were studied.

These results demonstrate that compound 4c could be further structurally modified as pesticidal agents. It will lay the foundation for future application of osthole derivatives as pesticides. © 2020 Society of Chemical Industry.

These results demonstrate that compound 4c could be further structurally modified as pesticidal agents. It will lay the foundation for future application of osthole derivatives as pesticides. © 2020 Society of Chemical Industry.