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51.
Beatriz F. dos Santos Caroline F. Pereira Mikaela P. Pinz Aline R. de Oliveira George Brand Ramesh Katla Ethel A. Wilhelm Cristiane Luchese Nelson L.C. Domingues 《应用有机金属化学》2020,34(7):e5650
Functionalization of 2,1,3-benzothiadiazole (BTD) with thiols at C-5 position remains low explored. Moreover, the arylthiol-substitutions at this position are also unexplored and can not be found by a SN2 or SN1 reaction. In this sense, herein we present a new palladium-catalyzed methodology for a wide variety of unpublished 5-arylsulfanyl-benzo-2,1,3-thiadiazole derivatives synthesis with moderate to high yields using a low catalytic loading of Pd(L-Pro)2 as low-coast, and efficient catalyst in low reaction time. Besides, we concluded that the pKa of thiol species has an important role in this catalysis, mainly in the CMD like catalytic cyclo process, which strongly interferes in the reaction yields. Furthermore, arylsulfanyl-benzo-2,1,3-thiadiazoles derivatives have been assessed (in vitro) as potential acetylcholinesterase inhibitors. 相似文献
52.
Marília Cavalcanti Coriolano Cristiane Moutinho Lagos de Melo Flávio de Oliveira Silva Giuliana Viegas Schirato Camila Souza Porto Paulo Jorge Parreira dos Santos Maria Tereza dos Santos Correia Ana Lúcia Figueiredo Porto Ana Maria dos Anjos Carneiro-Leão Luana Cassandra Breitenbach Barroso Coelho 《Applied biochemistry and biotechnology》2014,172(5):2682-2693
Parkia pendula seed lectin was used to treat cutaneous wounds of normal and immunocompromised mice, inducing cicatrization. Methotrexate (0.8 mg/kg/week) was used as immunosuppressive drug. Wounds were produced in the dorsal region (1 cm2) of female albino Swiss mice (Mus musculus), health and immunocompromised. Wounds were daily topically treated with 100 μL of the following solutions: (1) control (NaCl 0.15 M), (2) control Im (0.15 M NaCl), (3) P. pendula seed lectin (100 μg/mL), and (4) P. pendula seed lectin Im (100 μg/mL). Clinical evaluation was performed during 12 days. Biopsies for histopathology analysis and microbiological examinations were carried out in the second, seventh, and 12th days. The presence of edema and hyperemia was observed in all groups during inflammatory period. The first crust was detected from the second day, only in the groups treated with P. pendula seed lectin. Microbiological analysis of wounds from day 0 to day 2 did not show bacterium at P. pendula seed lectin group; however, Staphylococcus sp. was detected every day in the other groups. The lectin markedly induced a total wound closing at P. pendula seed lectin and P. pendula seed lectin Im groups on 11th day of evolution. The present study suggests that P. pendula seed lectin is a biomaterial potential to show pharmacological effect in the repair process of cutaneous wounds. 相似文献
53.
Cristiane dos Santos Luis Fernando Wentz Brum Robelsa de Fátima Vasconcelos Sérgio Knorr Velho João Henrique Zimnoch dos Santos 《Journal of Sol-Gel Science and Technology》2018,86(2):351-364
Natural dyes, namely, indigo carmine, cochineal carmine, curcumin and annatto, were encapsulated in silica by a sol-gel method and applied in the dyeing of different textile fibers by exhaustion. For comparative reasons, dyeing using the free (non-encapsulated) bare dyes was also carried out. The hybrid materials were analyzed by a set of techniques to investigate their elemental, structural, textural and morphological properties, and the results showed that it was possible to obtain stable natural dyes for applications in textile dyeing. The silica-structured dyes showed better affinities with the fibers (WO, PA, PAC and PET) in dyeing with cochineal carmine, while cotton (CO) showed better affinities with the encapsulated curcumin and annatto dyes. The performances of the encapsulated dyes were evaluated by color and washing fastness measurements and resulted in improved dye absorption and wash fastness properties. The color change and color transfer measurements of the encapsulated dyes were better (rated at 4–5 on a scale of 1–5) compared to the bare dyes. 相似文献
54.
Cristiane Antoniazzi Camila Alves de Lima Rafael Marangoni Almir Spinelli Eryza Guimarães de Castro 《Journal of Solid State Electrochemistry》2018,22(5):1373-1383
This paper reports the voltammetric determination of 17β-estradiol in urine and buttermilk samples using a simple detector based on a carbon paste electrode (CPE) modified with copper(II) oxide (CuO). The CuO was obtained by the Pechini method and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive (EDS), Fourier transform infrared (FTIR), and Raman spectroscopies. Cyclic voltammetry (CV) and square-wave voltammetry (SWV) demonstrated that the CuO-modified carbon paste electrode (CuO/CPE detector) displayed much higher electrocatalytic activity in the 17β-estradiol oxidation reaction than the CPE without modification, exhibiting a low detection limit of 21.0 nmol L?1 with a wide linear range from 60.0 to 800.0 nmol L?1 (R = 0.998). Satisfactory results were obtained for the determination of 17β-estradiol in human urine and buttermilk samples. The proposed electrochemical detector offers high repeatability, stability, fast response, low cost, and potential for practical application in the quantification of this hormone. 相似文献
55.
The crystal and molecular structure of 2,5-dimethyl-3,4-diacetylfuran has been determined by direct methods using CuK. photographic data. Refinement by full-matrix least-squares methods gave a finalR factor of 0·097. The crystals are monoclinic: space groupP21/c,a =14·92(2),b = 4·09(1),c =16·68(3) Å and = 109·7(5) °;Z = 4. The furan ring of the molecule is planar, and the exocyclic atoms bound to the atoms of the ring lie close to the ring plane. The planes of the acetyl groups are tilted by 16 ° and 47 ° with respect to the ring plane. The exocyclic bond angles of this compound are significantly different from the equivalent angles in furan. 相似文献
56.
Fabio D. Cukiernik Andrs Zelcer Maria Teresa Garland Ricardo Baggio 《Acta Crystallographica. Section C, Structural Chemistry》2008,64(11):o604-o608
An interesting case of `halogen‐bonding‐promoted' crystal structure architecture is presented. The two title compounds, C8H8Br2O2 and C8H8I2O2, have almost indistinguishable molecular structures but very different spatial organization, and this is mainly due to differences in the halogen‐bonding interactions in which the different species present, i.e. Br and I, take part. The dibromo structure exhibits a π‐bonded columnar array involving all four independent molecules in the asymmetric unit, with intercolumnar interactions governed by C—Br...Br—C links and with no C—Br...O/N interactions present. In the diiodo structure, instead, the C—I...O synthon prevails, defining linear chains, in turn interlinked by C—I...I—C interactions. 相似文献
57.
The title compound [Cu(PO4H2)(C11H7N2O2)]n presents antiferromagnetic behavior. It has a polymeric one-dimensional structure in which the elemental links are tetranuclear units and the doubly protonated phosphates and the bipyridinemonocarboxylates act in a bridging mode. The magnetic behavior is described using an alternating chain model, with J = -3.32 cm (-1), alpha = 0.7, and g = 2.05. 相似文献
58.
Developing exact models of combustion instabilities is not an easy task to carry out and requires a great deal of time prior to obtaining success. The present study proposes a low-order model for pressure oscillations that does not require any knowledge of the systems, any new physical findings nor intricate details regarding its operating condition. This new approach is obtained using a Modified Van der Pol’s equation (MVDP) which is tuned by use of a Dual Extended Kalman Filter (DKEF) as a recursive estimator with perspectives in control by computer. This phenomenological model is used to predict the pressure signal from a variety of different combustors. Input data were taken from experimental cases such as a Rijke tube, a gas turbine and a liquid-fuel aero-engine combustor. Furthermore, a simulation considering high frequency oscillations to show the capability of the new approach is presented. In all cases, the results demonstrated the feasibility of applying the tractable model MVDP and DKEF running together to investigate pressure oscillations in practical cases. 相似文献
59.
Sequential Voltammetric Determination of Uranium,Cadmium and Lead by Using the ex situ Bismuth Film Electrode: Application to Phosphate Fertilizers 下载免费PDF全文
Cristiane L. Jost Lara M. di Martos Luis Ferraz Paulo Cícero do Nascimento 《Electroanalysis》2016,28(2):287-295
A sequential voltammetric procedure for the determination of uranium, cadmium and lead was investigated at an ex situ bismuth film electrode (BiFE). First, the adsorptive stripping voltammetry was applied to assay the U(VI)‐cupferron complex in the differential pulse mode (detection limit of 1.0 µg L?1, 200 s accumulation time). Through the manipulation of the same aliquot of the sample, efforts were made to quantify cadmium and lead by square wave anodic stripping voltammetry. Detection limits of 2.03 µg L?1 for Cd (II) and 2.43 µg L?1 for Pb (II) were calculated (100 s accumulation time). The methodology was successfully applied to phosphate fertilizer samples after open vessel wet decomposition (HNO3/H2O2). The following value ranges were evaluated: U (VI) 37.2–150 mg kg?1, Pb (II) 78.3–204 mg kg?1 and Cd (II) 44.1–71.6 mg kg?1. Validation was performed by using the standard reference materials SRM‐695 – phosphate fertilizer – and SRM‐1643e – water. 相似文献
60.
Carbon Paste Electrode Modified with Biochar for Sensitive Electrochemical Determination of Paraquat 下载免费PDF全文
Cristiane Kalinke Antonio S. Mangrich Luiz H. Marcolino‐Junior Márcio F. Bergamini 《Electroanalysis》2016,28(4):764-769
The present work reports for the first time the determination of paraquat (PQ2+) by Differential Pulse Adsorptive Stripping Voltammetry (DPAdSV) using a carbon paste electrode modified (CPME) with biochar obtained from castor oil cake at different temperatures (200–600 °C). The best voltammetric response was verified using biochar yielded at 400 °C (CPME‐BC400). Linear dynamic range (LDR) for PQ2+ concentrations between 3.0×10?8 and 1.0×10?6 mol L?1 and a limit of detection (LOD) of 7.5×10?9 mol L?1 were verified. The method was successfully applied for PQ2+ quantification in spiked samples of natural water and coconut water. 相似文献