Search

Based on the retrieval of journals published on CNKI in the field of tourism, and the statistical analysis by Cite Space, this paper finds that: (1) in terms of the number of published papers, tourism research can be divided into three stages: infancy period in 1992-2000; Steady growth period in 2001-2011 years; Rapid decline period in 2012-2018 years. (2) The key institutions of tourism research are institutions of higher learning, among which Shaanxi Normal University and Zhongshan University have obvious institutional competitiveness. (3) Through the co-occurrence analysis of core authors and key words, eight core author groups and corresponding research fields can be divided. (4) The research direction of tourism mainly focuses on tourism industry, tourism resources, tourism development, tourist, the Belt and Road cultural tourism, rural tourism and city tourism. The future research will focus on the research direction of “big data”, “the Belt and Road tourism”, “poverty alleviation”, “global tourism” and “Rural Revitalization”.

Thioether and its derivatives are important active pharmacophores, widely adopted in the molecular design of agrochemicals. The introduction of thioether into drug intermediate is important to improve the liposolubility, hydrophobicity, and bioactivity of molecules. For development of novel insecticides targeting at ryanodine receptor (RyR), a series of anthranilic diamides of N‐pyridylpyrazole derivatives containing 3‐thioether were designed and synthesized. The structures of these compounds were verified using 1H NMR, 13C NMR, and HRMS. Their insecticidal activities against Mythimna separata (M. separata, oriental armyworms) and Plutella xylostella (P. xylostella, diamondback moths) were evaluated and the preliminary structure–activity relationship (SAR) was discussed, among which 9f, 9g exhibited favorable insecticidal activities against M. separata at 5 mg/L (9f, 50%; 9g, 40%). In addition, insecticidal activity of the intermediate 8 indicated that bromomethyl group at 3‐position of pyrazole moiety has an important impact for retaining insecticidal activity. Calcium imaging experiment and molecular docking were carried out to elaborate insecticidal mechanism from the perspective of experiment and molecular simulation, respectively. [ABSTRACT FROM AUTHOR]

BACKGROUND Diamide insecticides have attracted significant attention due to their high efficacy and low toxicity to non‐target organisms since they were introduced to the market. In order to tackle the problems of insecticide resistance and ecological safety, 16 novel nitrobenzene substituted anthranilic diamides with ester, hydroxyl or sulfonyl at the 3‐position of the pyrazole ring were designed and synthesized. RESULTS: All of these compounds possessed good activity against the ryanodine receptor (RyR) from Spodoptera frugiperda and relatively lower activity against mammalian RyR1, showing a better insect‐selectivity compared to chlorantraniliprole in a cell‐based assay. The molecular docking analysis predicted the binding conformations of these compounds, which showed a good correlation between the insecticidal activity and the binding scores. In vitro studies using a calcium imaging method demonstrated that the novel compounds could not only activate the RyR but may also target the dihydropyridine receptor on the plasma membrane of insect neurons, implicating a similar but not same mode of action. CONCLUSION: Substituted anthranilic diamides with an ester at the 3‐position of the pyrazole ring exhibited a promising insecticidal activity and better insect‐selectivity, which provided insight into the rational design of a new generation of effective diamide insecticides. [ABSTRACT FROM AUTHOR]

This brief presents computationally efficient block-adaptive algorithms for quadratic filters employing parallel-cascade realizations of the system model. Parallel-cascade realizations implement higher order Volterra systems using a parallel connection of multiplicative combinations of lower order systems. Such realizations are modular and therefore well-suited for very large scale integrate circuit implementation. They also permit efficient approximations of truncated Volterra systems. Mixed frequency- and time-domain realizations of the least-mean-square (LMS) adaptive filter, as well as that of a normalized LMS adaptive filter, are presented in this brief. The adaptive normalized LMS parallel-cascade quadratic filter has the advantages of computational simplicity and superior performance over its direct form, and unnormalized adaptive parallel-cascade counterparts. Index Terms - Adaptive filters, frequency-domain adaptation, nonlinear filters.