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A green and sustainable synthetic strategy for amide bond formation utilizing a visible light-promoted nitrone formation/rearrangement cascade was developed. This method utilized visible light as the sole and clean energy source without the need for an exogenous photoredox catalyst or additive. Moreover, nitrones are generated in situ, bypassing the isolation process and producing only nitrogen gas as a byproduct. The synthetic value of this protocol has potential applications in the syntheses of amides containing important natural products and drugbased complex molecules.

We report measurements of the electrical resistivity and ac magnetic susceptibility of single crystalline LaPt2Si2 under pressure, in order to investigate the interplay of superconductivity and CDW order. LaPt2Si2 exhibits a first order phase transition from a tetragonal to orthorhombic structure, accompanied by the onset of CDW order below TCDW = 76 K, while superconductivity occurs at a lower temperature of Tc = 1.87 K. We find that the application of pressure initially suppresses the CDW transition, but enhances Tc. At pressures above 2.4 GPa, CDW order vanishes, while both Tc and the resistivity A-coefficient reach a maximum value around this pressure. Our results suggest that the occurrence of a superconducting dome can be accounted for within the framework of BCS theory, where there is a maximum in the density of states upon the closure of the CDW gap.

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This study evaluates the effects of a broad-spectrum antibiotic (florfenicol) on antibiotic resistance genes (ARGs) and bacterial community structure in aquatic environments. We constructed an indoor aquatic microcosm model, adding different concentrations of florfenicol (0.1, 1, 10, 100 mg L−1), and water and sediment samples were collected after 0, 7, 30, and 60 days. qPCR and 16S rDNA amplicon sequencing were used to study the changes in the ARGs and bacterial community structure of the collected samples. The results show that the inclusion of florfenicol resulted in an increased abundance of the floR and optrA genes. Adding 100 mg L−1 florfenicol to the water increased the abundance of optrA gene copies with the maximum on the Day 7, and increased the abundance of floR gene copies with the maximum on Day 30. Adding 100 mg L−1 florfenicol to the sediment increased the abundance of floR and optrA genes by one order of magnitude on Day 60. Meanwhile, the average number of operational taxonomic units (OTUs) in the water samples was 257, and the average number of OTUs in sediment samples was 823. The bacterial community diversity and richness in sediments were higher than those in water. The difference between the maximal and minimal values of the Shannon diversity index in the water and sediment samples was 4.36 and 1.95, respectively. The effect of florfenicol on the bacterial community structure in water was much higher than that in sediment. At 30 days, the diversity index and richness index of the florfenicol treatment groups with 1 and 10 mg L−1 concentrations began to increase; at 60 days, the diversity and richness indices of the 100 mg L−1 florfenicol treatment group began to increase. The samples at the same sampling time in the sediments clustered closer together. The results of this study provide a scientific basis for guiding the rational use of florfenicol in aquaculture, maintaining a healthy and stable microecological environment in aquaculture, and provide theoretical data for environmental ecological risk assessment and safety management caused by microbial resistance under the abuse of florfenicol.

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