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排序方式: 共有566条查询结果,搜索用时 15 毫秒
541.
Adriano de Souza Carolino Matheus Moraes Biondo tefan lu Henrique Duarte da Fonseca Filho Pedro Henrique Campelo Jaqueline de Araújo Bezerra Cicero Mota Hidembergue Ordozgoith da Frota Vanderlei Salvador Bagnato Natalia Mayumi Inada Edgar Aparecido Sanches 《Molecules (Basel, Switzerland)》2022,27(15)
The development of conjugated polymer-based nanocomposites by adding metallic particles into the polymerization medium allows the proposition of novel materials presenting improved electrical and optical properties. Polyaniline Emeraldine-salt form (ES–PANI) has been extensively studied due to its controllable electrical conductivity and oxidation states. On the other hand, tungsten oxide (WO3) and its di-hydrated phases, such as WO3·2H2O, have been reported as important materials in photocatalysis and sensors. Herein, the WO3·2H2O phase was directly obtained during the in-situ polymerization of aniline hydrochloride from metallic tungsten (W), allowing the formation of hybrid nanocomposites based on its full oxidation into WO3·2H2O. The developed ES–PANI–WO3·2H2O nanocomposites were successfully characterized using experimental techniques combined with Density Functional Theory (DFT). The formation of WO3·2H2O was clearly verified after two hours of synthesis (PW2 nanocomposite), allowing the confirmation of purely physical interaction between matrix and reinforcement. As a result, increased electrical conductivity was verified in the PW2 nanocomposite: the DFT calculations revealed a charge transfer from the p-orbitals of the polymeric phase to the d-orbitals of the oxide phase, resulting in higher conductivity when compared to the pure ES–PANI. 相似文献
542.
Fragment-based and classical quantitative structure–activity relationships for a series of hydrazides as antituberculosis agents 总被引:1,自引:1,他引:0
Andrade CH Salum Lde B Castilho MS Pasqualoto KF Ferreira EI Andricopulo AD 《Molecular diversity》2008,12(1):47-59
Worldwide, tuberculosis (TB) is the leading cause of death among curable infectious diseases. Multidrug-resistant Mycobacterium tuberculosis is an emerging problem of great importance to public health, and there is an urgent need for new anti-TB drugs. In the present work, classical 2D quantitative structure-activity relationships (QSAR) and hologram QSAR (HQSAR) studies were performed on a training set of 91 isoniazid derivatives. Significant statistical models (classical QSAR, q (2) = 0.68 and r (2) = 0.72; HQSAR, q (2) = 0.63 and r (2) = 0.86) were obtained, indicating their consistency for untested compounds. The models were then used to evaluate an external test set containing 24 compounds which were not included in the training set, and the predicted values were in good agreement with the experimental results (HQSAR, [Formula: see text] ; classical QSAR, [Formula: see text]). 相似文献
543.
Festa C De Marino S Sepe V D'Auria MV Bifulco G Débitus C Bucci M Vellecco V Zampella A 《Organic letters》2011,13(6):1532-1535
Two unprecedented cyclic peptides, solomonamides A and B, were isolated from the marine sponge Theonella swinhoei. The structures were elucidated on the basis of comprehensive 1D and 2D NMR analysis and high-resolution mass spectrometry. A combined approach, involving Marfey's method, QM J based analysis, and DFT J/(13)C calculations, was used for establishing the absolute configuration of the entire molecule. Solomonamide A showed in vivo anti-inflammatory activity. 相似文献
544.
Adriano Polican Ciena Sonia Regina Yokomizo de Almeida Paulo Henrique de Matos Alves Regina de Sousa Bolina-Matos Fernando José Dias João Paulo Mardegan Issa Mamie Mizusaki Iyomasa Ii-sei Watanabe 《Micron (Oxford, England : 1993)》2011,42(8):871-876
The aim of this study was to evaluate histochemically and ultrastructurally the sternomastoid muscle (SM) of adults and aged rats, employing histochemic (NADH-TR reaction) and transmission electron microscopic methods. It was used 20 rats, divided into two groups: adults (n = 10), animals with 4 months of age, and aged group (n = 10), animals with 24 months of age. Five animals from each group were anesthetized with an overdose of urethane (3 g/kg i.p.), and the muscles dissected after the samples processing for histochemical reaction (NADH-TR). Three types of fibers were identified by their metabolic characteristics: fibers with high oxidative capacity (O), intermediate oxidative capacity (OG) and low oxidative capacity (G). For transmission electron microscopic method, the animals were anesthetized and perfused by modified Karnovsky solution and the tissues were postfixed in 1% osmium tetroxide solution, dehydrated and embedded in Spurr resin. It was performed ultra-thin sections for transmission electron microscopic analysis. The SM showed heterogeneity in their composition according to the fiber types, with significant difference (p < 0.05) when comparing the fibers types between the superficial and deep regions and between the adult and aged groups. It was observe a decrease between the comparison of the total fibers density and GO fiber, and an increase of the O fiber in aged group. Ultrastructural characteristics of muscle cells in aged group showed typical morphological changes, characterizing muscular atrophy. We conclude based on physiological ageing process, changes in muscle fibers classification, and ultrastructuraly, morphological alterations on muscle cells, characterizing a muscular atrophy. 相似文献
545.
Giampiero Palatucci Adriano Pisante 《Calculus of Variations and Partial Differential Equations》2014,50(3-4):799-829
We obtain an improved Sobolev inequality in \(\dot{H}^s\) spaces involving Morrey norms. This refinement yields a direct proof of the existence of optimizers and the compactness up to symmetry of optimizing sequences for the usual Sobolev embedding. More generally, it allows to derive an alternative, more transparent proof of the profile decomposition in \(\dot{H}^s\) obtained in Gérard (ESAIM Control Optim Calc Var 3:213–233, 1998) using the abstract approach of dislocation spaces developed in Tintarev and Fieseler (Concentration compactness. Functional-analytic grounds and applications. Imperial College Press, London, 2007). We also analyze directly the local defect of compactness of the Sobolev embedding in terms of measures in the spirit of Lions (Rev Mat Iberoamericana 1:145–201, 1985, Rev Mat Iberoamericana 1:45–121, 1985). As a model application, we study the asymptotic limit of a family of subcritical problems, obtaining concentration results for the corresponding optimizers which are well known when \(s\) is an integer (Rey in Manuscr Math 65:19–37, 1989, Han in Ann Inst Henri Poincaré Anal Non Linéaire 8:159–174, 1991, Chou and Geng in Differ Integral Equ 13:921–940, 2000). 相似文献
546.
Dr. Adriano Ambrosi Prof. Martin Pumera 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(15):4748-4753
Graphene materials are generally prepared from the exfoliation of graphite oxide (GO) to graphene oxide, followed by subsequent chemical or thermal reduction. These methods, although efficient in removing most of the oxygen functionalities from the GO material, lack control over the extent of the reduction process. We demonstrate here an electrochemical reduction procedure that not only allows for precise control of the reduction process to obtain a graphene material with a well‐defined C/O ratio in the range of 3 to 10, but also one that is able to tune the electrocatalytic properties of the reduced material. A method that is able to precisely control the amount and density of the oxygen functionalities on the graphene material as well as its electrochemical behaviour is very important for several applications such as electronics, bio‐composites and electrochemical devices. 相似文献
547.
(R)(S)(E)-3,7-dimethyl-2-octene-1,8-dioic acid, (R)(S)(E)-1, also named callosobruchusic acid, has been synthetized in five steps using a simple reaction sequence based on the zirconium-catalyzed methylalumination of commercially available 4-pentyn-1-ol, 2a, or its O-tert-butyldimethylsilyl ether, 2b. 相似文献
548.
Cristiane Y. KawasokoCarlos E.D. Nazario Amanda S. SantanaLuiz H. Viana Gabriela R. HurtadoFrancisco A. Marques Gustavo FrenschPaulo R. de Oliveira Palimécio G. Guerrero Jr.Diego B. Carvalho Adriano C.M. Baroni 《Tetrahedron letters》2011,52(46):6067-6071
The hydroalumination of silylacetylenes with DIBAL-H followed by the addition of n-butyllithium generated in situ the (Z)-β-vinylorganosilane alanates intermediates, which were trapped with butyltellurenyl bromide (C4H9TeBr), furnishing exclusively the (E)-1-butyltelluro-1-tri(organyl)silyl-2-organyl-1-alkenes in 45-70% yields. These telluro(silyl)ketene acetals were utilized as substrates in Sonogashira cross-coupling Pd-catalyzed reactions, furnishing the (Z)-1,4-diorganyl-2-tri(organyl)silyl-1-buten-3-ynes with total control of regio- and stereochemistry in 62-80% yield. 相似文献
549.
We studied the electroanalytical performances of chemically-modified graphenes (CMGs) containing different defect densities and amounts of oxygen-containing groups, namely graphite oxide (GPO), graphene oxide (GO), thermally reduced graphene oxide (TR-GO) and electrochemically reduced graphene oxide (ER-GO) by comparing the sensitivity, selectivity, linearity and repeatability towards the oxidation of DNA bases. We have observed that for differential pulse voltammetric (DPV) detection of adenine and cytosine, all CMGs showed enhanced sensitivity to oxidation, while for guanine and thymine, ER-GO and TR-GO exhibited much improved sensitivity over bare glassy carbon (GC) as well as over GPO and GO. There is also significant selectivity enhancement when using GPO for adenine and TR-GO for thymine. Our results have uncovered that the differences in surface functionalities, structure and defects of various CMGs largely influence their electrochemical behaviour in detecting the oxidation of DNA bases. The findings in this report will provide a useful guide for the future development of label-free electrochemical devices for DNA analysis. 相似文献
550.