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The present study is an attempt to improve thermal, mechanical and electrical properties of poly (methyl methacrylate) (PMMA). For this purpose, vinyltriethoxysilane (VTES) was grafted covalently on the surface of graphene oxide (GO). This VTES functionalized graphene oxide (VGO) was dispersed in the PMMA matrix using the solution casting method. The morphology of the resultant PMMA/VGO nanocomposites was analyzed by SEM indicating well-dispersed VGO in the PMMA matrix. Thermal stability, tensile strength and thermal conductivity increased by 90%, 91% and 75%, respectively, whereas volume electrical resistivity and surface electrical resistivity reduced to 9.45 × 105 Ω/cm and 5.45 × 107 Ω/cm2, respectively.
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AIM AND OBJECTIVE: Europium (Eu(III)) is a rare-earth metal, the softest, least dense, and most volatile member of lanthanides. It is greatly applied in the control rods of nuclear reactors. Although various extraction methods of Eu(III) have been reported, we present a novel mixture of easily available extractants in optimized experimental conditions to extract it efficiently, quickly, and cost-effectively. MATERIALS AND METHODS: Physical-chemical conditions (e.g., pH, equilibration time, temperature, europium concentration, extractants concentration, presence of specific metal ions) were optimized. The extractants, picrolonic acid (HPA) and di-n-butylsulfoxide (DBSO), were thoroughly mixed at equal concentration in chloroform. Standard Eu(III) solution was used for determining the method's accuracy. Reagent blank was prepared under identical conditions but without metal ions. Using the metallochromic dye arsenazo III as the blank, the absorbance of Eu(III) was measured spectrophotometrically at 651 nm. The distribution ratio (i.e., Eu(III) concentration in the aqueous phase before and after extraction) defined the extraction yield. RESULTS: HPA/DBSO mixture (0.01 M) had a synergistic effect on Eu(III) extraction (1.19×10-5 mole/dm3), achieving a maximum yield (≥ 99%) at pH 2, during 5 minutes equilibration at room temperature. Eu(III) extraction was reduced depending on the nature but not on the metal ions concentration. Extractants could be recycled four times without consequent degradation. Deionized water (dH2O) was the best strippant besides its availability and low-cost. The composition of the extracted adduct was defined as Eu(PA)3.2DBSO. CONCLUSION: This alternative method was found to be stable, simple, rapid, cost-effective, reliable, accurate and sensitive. It could be used for Eu(III) extraction and refining on a pilot plant scale.
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Europio , Pirazolonas , Europio/química , Iones , TemperaturaRESUMEN
This study was carried out to synthesize benzotriazole-based bis-Schiff base scaffolds (1-20) and assess them in vitro for α-glucosidase inhibitory potentials. All the synthetics analogs based on benzotriazole-based bis-Schiff base scaffolds were found to display an outstanding inhibition profile on screening against the α-glucosidase enzyme. The synthetic scaffolds showed a varied range of inhibition profiles having IC50 values ranging from 1.10 ± 0.05 µM to 28.30 ± 0.60 µM when compared to acarbose as a standard drug (IC50 = 10.30 ± 0.20 µM). Among the series, fifteen scaffolds 1-3, 5, 6, 9-16, 18-20 were identified to be more potent than standard acarbose, while the five remaining scaffolds 4, 7, 8, 16, and 17, also showed potency against the α-glucosidase enzyme but were found to be less potent than standard acarbose. The structure of all the newly synthesized scaffolds was confirmed using different spectroscopic techniques such as HREI-MS and 1H- and 13C- NMR spectroscopy. To find a structure-activity relationship, molecular docking studies were carried out to understand the binding mode of the active inhibitors with the active sites of the enzyme and the results supported the experimental data.