RESUMEN
In the pursuit of novel insecticides with high activity and a unique mode of action on the GABA receptor, a series of phenylpyrazole esterified derivatives (PEs) were synthesized using an improved Pinner reaction with high selectivity. Lewis acid catalysis was employed in a one-step solvent-thermal method to convert the cyano group of fipronil into an ester unit. FeCl3 was found to exhibit the highest selectivity for PEs synthesis, yielding PEs at 96.4%, with the byproduct being phenylpyrazole amide (PE0) at 2.1%. Initial biological assays indicated superior insecticidal activity of the target compounds against Plutella xylostella and Mythimna separata compared to fipronil. Particularly, the smaller and shorter ester units, PE3, PE5, and PE8, demonstrated 2-2.5 times higher insecticidal activity against P. xylostella than fipronil. The higher activity of ester units compared to amide and acylhydrazone units can be attributed to the enhanced lipid solubility of PEs. Additionally, it may be due to the impact of PEs on the neurotransmitter nACh or the coordination of calcium and chloride ions with the ester's -CâO and -O- bonds, blocking the chloride ion channel. Hydrophobic parameters were confirmed by reversed-phase high-performance liquid chromatography (HPLC), indicating the enhanced lipophilicity conferred by the ester units of PEs. Molecular docking and CoMFA analysis preliminarily validated the strong interactions and structure-activity relationships between PEs and the GABA receptor and nACh receptor in P. xylostella. Furthermore, under simulated natural sunlight, PEs exhibited photodegradation capabilities, transforming back into fipronil parent fragments and enhancing their insecticidal activity. Moreover, PEs displayed excellent fluorescent properties, enabling self-detection of residues. These research findings provide new insights and directions for the development of efficient pesticides, with potential wide applications in the fields of medicine and biosensors.
Asunto(s)
Insecticidas , Mariposas Nocturnas , Animales , Insecticidas/química , Simulación del Acoplamiento Molecular , Relación Estructura-Actividad , Mariposas Nocturnas/metabolismo , Receptores de GABA/metabolismo , Amidas , Ésteres , Ácido gamma-AminobutíricoRESUMEN
Ligand-gated ion channels are essential in living organisms, and sulfonamides have antibacterial effects and can be readily coordinated with metal ions with good biological activity. A series of fluorescent ligand-gated ion channel fused arylpyrazole sulfonamide skeletons (APSnM) were synthesized based on a one-pot ultrasound strategy promoted by an inorganic base. APSnM had a high fluorescence quantum yield and a large Stokes shift in ethanol solvent. The ligand bonded ions took on a different color from the ligand and can be used as a probe to detect their own residue on plant surfaces. Their hydrophobic parameters and the fluorescence distribution in Chinese cabbage leaves indicated that APSnM significantly increased the phloem mobility of the plant. The insecticidal activity of APS3Na was higher (LC50 = 7.2423 µg/mL) than that of fipronil (15.2312 µg/mL) against Plutella xylostella, and the mechanism of high insecticidal activity of APS3Na was simulated by molecular docking, which confirmed its strong interactions with the GABA and nACh receptors of Plutella xylostella. Analysis of the crystal structure of these ligand-gated ion channels further confirmed the consistency of their structure and biological activity.
Asunto(s)
Insecticidas , Canales Iónicos Activados por Ligandos , Insecticidas/química , Floema , Ligandos , Simulación del Acoplamiento Molecular , Ácido gamma-Aminobutírico/farmacología , Sulfonamidas/farmacología , IonesRESUMEN
In order to find a novel type of fluorescent phloem-mobile insecticides, a facile one-pot solvothermal strategy via fipronil addition-elimination substitution reaction with the corresponding acyl chloride derivatives has been employed to construct series of phenylpyrazole amide derivatives (PAs) fused olefin moieties in high yields. The investigation for insecticidal bioactivities of PAs against 3rd instar larvae of Plutella xylostella exhibited better activities than that of fipronil, which can be elucidated by enhanced phloem mobility and calcium ions' coordination with amide N-C=O, CC double bonds and chloride ions, extended conjugate moieties and decreasing steric hindrance of the stereoscopic structure. The introduction of amide units conferred phloem mobility to PAs, which was evaluated by the hydrophobic parameters determined with reversed-phase HPLC through the chromatographic capacity factor. By introducing conjugate moieties and organic chromophore into phenylpyrazole parent structure to increase their conjugation degree and light absorption abilities, PAs exhibited good photodegradation properties. The relationships between extended conjugate moieties of parent structure, electronegativity of substituted groups and photodegradation properties have been discussed. The olefin units connected to PAs caused electronic absorption and fluorescent wavelengths bathochromic shifted. Under simulated solar irradiation, PAs can be reconverted into fipronil parent fragments by photodegradation, thereby enhancing their insecticidal activity. The fluorescent quantum yields of PAs were almost 4 times that of fipronil, which also laid a foundation for the natural degradation and fluorescence detection of insecticide residues.
Asunto(s)
Insecticidas , Plaguicidas , Alquenos , Amidas , Animales , Floema , FotólisisRESUMEN
Although air pollution is an important environmental concern in tourism, it is rarely studied in the field of sustainable tourism. Thus, we investigated how air pollution influences tourists' pro-environmental behavioral intentions (TPEBIs) through two laboratory experiments (studies 1 and 2) and one field study (study 3). Study 1 (nâ¯=â¯104) revealed the negative influence of air pollution on TPEBIs, both explicitly and implicitly. Study 2 (nâ¯=â¯108) further explored the mediating effect of state anxiety on the relationship between air pollution and TPEBIs. Furthermore, study 3 (nâ¯=â¯350) investigated a real sample of traveling tourists. Study 3's results confirmed the laboratory findings of studies 1 and 2, indicating the buffering effect of tourism nostalgia (i.e., a moderated mediation model) in a real traveling context. These findings advance the understanding of air pollution's impact on TPEBIs and can serve as practical advice for sustainable tourism management.
Asunto(s)
Intención , Contaminación del Aire , Humanos , ViajeRESUMEN
As the common saying goes: All's well that ends well. This research was the first to explore whether the end effect could be observed in the perception of air pollution and further examined the effect of perceived difference on the end effect. In Experiment 1, participants went through a short trial of 30 severe air pollution pictures and a long trial of 45 pollution pictures containing 15 extra moderate pollution pictures at the end. The results showed preference for the long trial as well as more willingness to experience it again, which verified the end effect. In Experiment 2, the long trial was adjusted to 45 severe air pollution pictures, which caused the end effect to disappear. In Experiment 3, it was confirmed that perceived difference had an impact on the end effect, as the end effect worked when subjects cognitively focused on the variated pollution extent but disappeared when they focused on the air pollution quality. These results advance our understanding by directly demonstrating the influence of perceived difference on the end effect as well as providing a useful view to intervene in people's perception of air pollution. Further theoretical and practical implications are discussed.
Asunto(s)
Contaminantes Atmosféricos , Contaminación del Aire , Contaminación AmbientalRESUMEN
In the current work, a novel 2D numerical model of stationary grids was developed for reciprocating magnetic refrigerators, with Gd plates, in which the magneto-caloric properties, derived from the Weiss molecular field theory, were adopted for the built-in energy source of the magneto-caloric effect. The numerical simulation was conducted under the conditions of different structural and operational parameters, and the effects of the relative fluid displacement (φ) on the specific refrigeration capacity (qref) and the Coefficient of Performance (COP) were obtained. Besides the variations of entropy, the generation rate and number were studied and the contours of the local entropy generation rate are presented for discussion. From the current work, it is found that with an increase in φ, both the qref and COP followed the convex variation trend, while the entropy generation number (Ns) varied concavely. As for the current cases, the maximal qref and COP were equal to 151.2 kW/m3 and 9.11, respectively, while the lowest Ns was the value of 2.4 × 10-4 K-1. However, the optimal φ for the largest qref and COP, and for the lowest Ns, were inconsistent, thus, some compromises need be made in the optimization of magnetic refrigerators.