175 research outputs found

    Existence of entire solutions of nonlinear difference equations

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    summary:In this paper we obtain that there are no transcendental entire solutions with finite order of some nonlinear difference equations of different forms

    (E)-1-[(2-Chloro-5-methyl­pyridin-3-yl)methyl­ene]thiosemicarbazide

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    The title compound, C8H9ClN4S, which has potential insecticidal activity, was synthesized by the reaction of 2-chloro-5-methyl­nicotinaldehyde and thio­semicarbazide. In the crystal structure, the mol­ecules are linked via inter­molecular N—H⋯N, N—H⋯S and N—H⋯Cl hydrogen bonds, forming a three-dimensional network stacked down a

    Three Dimensional Quantitative Structure-Activity Relationships of Sulfonamides Binding Monoclonal Antibody by Comparative Molecular Field Analysis

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    The three-dimensional quantitative structure-activity relationship (3D-QSAR) model of sulfonamide analogs binding a monoclonal antibody (MabSMR) produced against sulfamerazine, was carried out by comparative molecular field analysis (CoMFA). The affinities of MabSMR, expressed as Log10IC50, for 17 sulfonamide analogs were determined by competitive fluorescence polarization immunoassay (FPIA). Removal of two outliers from the initial set of 17 sulfonamide analogs improved the predictability of the models. The 3D-QSAR model of 15 sulfonamides resulted in q2cv values of 0.600, and r2 values of 0.995, respectively. This novel study combining FPIA with CoMFA demonstrates that multidisciplinary research can be used as a useful tool to investigate antigen-antibody interactions and provide information required for design of novel haptens, which may result in new antibodies with properties already optimized by an antibody-based immunoassay

    Investigation of Antigen-Antibody Interactions of Sulfonamides with a Monoclonal Antibody in a Fluorescence Polarization Immunoassay Using 3D-QSAR Models

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    A three-dimensional quantitative structure-activity relationship (3D-QSAR) model of sulfonamide analogs binding a monoclonal antibody (MAbSMR) produced against sulfamerazine was carried out by Distance Comparison (DISCOtech), comparative molecular field analysis (CoMFA), and comparative molecular similarity indices analysis (CoMSIA). The affinities of the MAbSMR, expressed as Log10IC50, for 17 sulfonamide analogs were determined by competitive fluorescence polarization immunoassay (FPIA). The results demonstrated that the proposed pharmacophore model containing two hydrogen-bond acceptors, two hydrogen-bond donors and two hydrophobic centers characterized the structural features of the sulfonamides necessary for MAbSMR binding. Removal of two outliers from the initial set of 17 sulfonamide analogs improved the predictability of the models. The 3D-QSAR models of 15 sulfonamides based on CoMFA and CoMSIA resulted in q2 cv values of 0.600 and 0.523, and r2 values of 0.995 and 0.994, respectively, which indicates that both methods have significant predictive capability. Connolly surface analysis, which mainly focused on steric force fields, was performed to complement the results from CoMFA and CoMSIA. This novel study combining FPIA with pharmacophore modeling demonstrates that multidisciplinary research is useful for investigating antigen-antibody interactions and also may provide information required for the design of new haptens

    Synthesis and fungicidal activity of pyrazole derivatives containing 1,2,3,4-tetrahydroquinoline

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    Additional file 3. Structural information (CIF) for Compound 10g

    Design, synthesis, and biological activity of novel heptacyclic pyrazolamide derivatives : a new candidate of dual-target insect growth regulators

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    Insect growth regulators (IGRs) can cause abnormal growth and development in insects, resulting in incomplete metamorphosis or even death of the larvae. Ecdysone receptor (EcR) and chitinase in insects play indispensable roles in the molting process. Ecdysone analogues and chitinase inhibitors are considered as potential IGRs. In order to find new and highly effective IGR candidates, based on the structure-activity relationship and molecular docking results of the active compound 6i (3-(tert-butyl)-N-(4-(tert-butyl)phenyl)-1-phenyl-1H-pyrazole-5-carboxamide) discovered in our previous work, we changed the t-butyl group on the pyrazole ring into heptacycle to enhance the hydrophobicity. Consequently, a series of novel heptacyclic pyrazolamide derivatives were designed and synthesized. The bioassay results demonstrated that some compounds showed obvious insecticidal activity. Especially, D-27 (N-(4-(tert-butyl)phenyl)-2-phenyl-2,4,5,6,7,8-hexahydrocyclohepta[c]pyrazole-5-carboxamide) showed good activities against Plutella xylostella (LC50, 51.50 mg.L-1) and Mythimna separata (100% mortality at 2.5 mg.L-1). Furthermore, protein validation indicated that D-27 acts not only on the EcR but also on chitinase Of ChtI. Molecular docking and molecular dynamics simulation explained the vital factors in the interaction between D-27 and receptors. D-27 may be a new lead candidate with a dual target in which Of ChtI shall be the main one. This work created a new starting point for discovering a novel type of IGRs
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