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排序方式: 共有348条查询结果,搜索用时 15 毫秒
281.
282.
Brito Vinicius B. M. Santos Gilmar F. Silva Thiago D. S. Souza Júlia L. C. Militão Gardenia C. G. Martins Felipe T. Silva Fábio P. L. Oliveira Boaz G. Araújo Edigenia C. C. Vasconcellos Mário L. A. A. Lima-Júnior Claudio G. Alencar-Filho Edilson B. 《Molecular diversity》2020,24(1):265-281
Molecular Diversity - Quaternary or spirocyclic 3-substituted-3-hydroxy-2-oxindole is considered a privileged scaffold. In other words, it is a molecular core present on several compounds with a... 相似文献
283.
Coutinho LH Cavasso-Filho RL Rocha TC Homem MG Figueira DS Fonseca PT Cruz FC Naves de Brito A 《Physical review letters》2004,93(18):183001
We investigate the angular distribution of photoionization fragments at low photon energies (12-40 eV) in an open shell atom, by synchrotron radiation recoil ion momentum spectroscopy in a laser cooled and trapped sample. For cesium atoms, for which relativistic effects play an important role and the ion recoil is relatively small, we could determine large and rapid changes of the asymmetry parameter beta from two, observed for s electrons outside resonances and far from the Cooper minimum. They can be explained by relativistic effects and interchannel coupling arising from final state configuration mixing. 相似文献
284.
E.W. Dias A.P. Baêta Scarpelli L.C.T. Brito M. Sampaio M.C. Nemes 《The European Physical Journal C - Particles and Fields》2008,55(4):667-681
We extend a constrained version of implicit regularization (CIR) beyond one-loop order for gauge field theories. In this framework,
the ultraviolet content of the model is displayed in terms of momentum loop integrals order by order in perturbation theory
for any Feynman diagram, while the Ward–Slavnov–Taylor identities are controlled by finite surface terms. To illustrate, we
apply CIR to massless abelian gauge field theories (scalar and spinorial QED) to two-loop order and calculate the two-loop
beta-function of spinorial QED.
PACS 11.10.Gh; 11.15.Bt; 11.15.-q 相似文献
285.
Paulo B. Brito António G. St. Aubyn 《Numerical Functional Analysis & Optimization》2013,34(11):1116-1126
Recently, a new method for computing the analytical solution of a delay differential equation was developed considering a constant initial function. It is based on the existence of a specific class of polynomials in the delay. In this article, we extend this new method to the case of a continuous initial function. We also show the relationship between the new solution's method and the solution expressed in terms of the Lambert function. 相似文献
286.
de Souza Caroline Gondim Martins Fátima Itana Chaves Custódio Zocolo Guilherme Julião Figueiredo José Edson Fontes Canuto Kirley Marques de Brito Edy Sousa 《Analytical and bioanalytical chemistry》2018,410(26):6827-6836
Analytical and Bioanalytical Chemistry - The rapid and accurate quantification of lipopeptide families in biological samples are challenging. We present the development and validation of a method... 相似文献
287.
Layane A. L. Silva Andr A. L. Silva Maria A. S. Rios Manoel P. Brito Alyne R. Araújo Durcilene A. Silva Ramn R. Pea-Garcia Edson C. Silva-Filho Janildo L. Magalhes Jos M. E. Matos Josy A. Osajima Eduardo R. Triboni 《Molecules (Basel, Switzerland)》2021,26(5)
Molybdates are biocidal materials that can be useful in coating surfaces that are susceptible to contamination and the spread of microorganisms. The aim of this work was to investigate the effects of copper doping of hydrated cobalt molybdate, synthesized by the co-precipitation method, on its antibacterial activity and to elucidate the structural and morphological changes caused by the dopant in the material. The synthesized materials were characterized by PXRD, Fourier Transformed Infrared (FTIR), thermogravimetric analysis/differential scanning calorimetry (TG/DSC), and SEM-Energy Dispersive Spectroscopy (SEM-EDS). The antibacterial response of the materials was verified using the Minimum Inhibitory Concentration (MIC) employing the broth microdilution method. The size of the CoMoO4·1.03H2O microparticles gradually increased as the percentage of copper increased, decreasing the energy that is needed to promote the transition from the hydrated to the beta phase and changing the color of material. CoMoO4·1.03H2O obtained better bactericidal performance against the tested strains of Staphylococcus aureus (gram-positive) than Escherichia coli (gram-negative). However, an interesting point was that the use of copper as a doping agent for hydrated cobalt molybdate caused an increase of MIC value in the presence of E. coli and S. aureus strains. The study demonstrates the need for caution in the use of copper as a doping material in biocidal matrices, such as cobalt molybdate. 相似文献
288.
Vanessa Brito Gilberto Alves Paulo Almeida Samuel Silvestre 《Molecules (Basel, Switzerland)》2021,26(7)
Steroids constitute a unique class of chemical compounds, playing an important role in physiopathological processes, and have high pharmacological interest. Additionally, steroids have been associated with a relatively low toxicity and high bioavailability. Nowadays, multiple steroidal derivatives are clinically available for the treatment of numerous diseases. Moreover, different structural modifications on their skeleton have been explored, aiming to develop compounds with new and improved pharmacological properties. Thus, steroidal arylidene derivatives emerged as a relevant example of these modifications. This family of compounds has been mainly described as 17β-hydroxysteroid dehydrogenase type 1 and aromatase inhibitors, as well as neuroprotective and anticancer agents. Besides, due to their straightforward preparation and intrinsic chemical reactivity, steroidal arylidene derivatives are important synthetic intermediates for the preparation of other compounds, particularly bearing heterocyclic systems. In fact, starting from arylidenesteroids, it was possible to develop bioactive steroidal pyrazolines, pyrazoles, pyrimidines, pyridines, spiro-pyrrolidines, amongst others. Most of these products have also been studied as anti-inflammatory and anticancer agents, as well as 5α-reductase and aromatase inhibitors. This work aims to provide a comprehensive overview of steroidal arylidene derivatives described in the literature, highlighting their bioactivities and importance as synthetic intermediates for other pharmacologically active compounds. 相似文献
289.
Thiago O. Mendes Georgia M. A. Junqueira Brenda L. S. Porto Charles D. Brito Fernando Sato Marcone A. L. de Oliveira Virgilio Anjos Maria J. V. Bell 《Journal of Raman spectroscopy : JRS》2016,47(6):692-698
This paper presents a systematic analysis of the infrared absorption spectra and Raman scattering of the triacylglycerol molecule predominant in raw bovine milk. Gas chromatography measurements were also performed and revealed the palmitic, stearic, and oleic acids as the most predominant fatty acids in the composition of milk. Based on the gas chromatography results, infrared, and Raman spectra of the triacylglycerol with this combination of fatty acids were simulated. The theoretical spectra were compared with the experimental ones of milk fat and fluid raw milk. Assignment of bands of milk fat was proposed, which can be used for a quality monitoring of the product. We also performed a multivariate model of partial least squares from samples of fluid milk with different concentrations of fat. As a result, the most important variables in the projection were selected as vibrational markers for quality monitoring and quantifying of this important constituent of milk. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
290.
Luiz Bruno De Sousa Sabino Francesco Copes Solne Saulais Edy Sousa De Brito Ivanildo Jos Da Silva Júnior Tien Canh Le Mircea Alexandru Mateescu Diego Mantovani 《Molecules (Basel, Switzerland)》2022,27(21)
Anthocyanins obtained from jambolan have been used as active agents in different carboxymethyl starch-based tablet formulations and their release profiles evaluated in simulated gastric fluids (SGF) and simulated intestinal (SIF) fluids. Structural analysis highlighted a strong interaction between anthocyanins and carboxymethyl starch, evidenced by scanning electron microscopy and infrared analysis. Tablet dissolution behavior varied according to the pH of the media, being controlled by the swelling and/or erosion of the polymeric matrix. Various formulations for immediate, fast, and sustained release of anthocyanins for 30 min, 2 h and 12 h of dissolution have been developed. It was found that monolithic carboxymethyl starch tablets loaded with powdered jambolan extract efficiently afforded the complete delivery (100% of anthocyanins) to different sites of the simulated gastrointestinal tract and ensured the stability of these pigments, which maintained their antioxidant activity. 相似文献