F R Theory
Mostrando 1-12 de 105 artigos, teses e dissertações.
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1. Nicotine as a Catalyst for Chlorination Promoted by Hypochlorous Acid: Experimental and Theoretical Studies
There is robust evidence of the hypochlorous acid (HClO)-mediated damage in biomolecules, and nicotine boosts the chlorination potency of HClO. We present experimental and theoretical evidence of the mechanism by which nicotine catalyzes the chlorination of pyranine. The rate constants for chlorination of pyranine by HClO were measured in the presence (5.3 �
Journal of the Brazilian Chemical Society. Publicado em: 2023
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2. Intercalation of Apocarotenoids from Annatto (Bixa orellana L.) into Layered Double Hydroxides
Synthetic conditions were evaluated to intercalate norbixin into layered double hydroxides (LDH). Norbixin was isolated from a hydrosoluble commercial annatto extract. LDH samples comprising M2+/Al3+ (M = Mg, Zn) were synthesized by coprecipitation and characterized by X-ray diffraction, thermal analysis coupled to mass spectrometry, vibrational spectroscopi
J. Braz. Chem. Soc.. Publicado em: 2020-11
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3. Mechanistic Investigation of DBU-Based Ionic Liquids for Aza-Michael Reaction: Mass Spectrometry and DFT Studies of Catalyst Role
1,8-Diazabicyclo[5.4.0]undec-7-ene (DBU)-based ionic liquids (ILs) has exhibited a high catalytic activity in the aza-Michael reactions compared to conventional catalysts and with imidazole-based ILs. In the present work DBU-based ILs showed high catalytic potential for aza-Michael addition of aromatic amines to 2-cyclohexen-1-one under solvent-free conditio
J. Braz. Chem. Soc.. Publicado em: 2020-09
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4. Understanding Solvent/Bixin Interactions by Raman Spectroscopy
In this work, Raman spectroscopy and density functional theory (DFT) calculations have been used in order to understand the nature of the interaction between the carotenoid bixin and organic solvents with dielectric constant varying from ca. 2 (toluene) to ca. 47 (dimethyl sulfoxide). Raman shifts registered for the main carotenoid marker band, the C=C stret
J. Braz. Chem. Soc.. Publicado em: 2020-07
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5. Qualidade de uso de mídias interativas na primeira infância e desenvolvimento infantil: uma análise multicritério,
Resumo Objetivos: (1) Elaborar um índice que possibilite mensurar a qualidade de uso de mídias interativas por crianças na primeira infância. (2) Verificar se há relação entre o índice e o desenvolvimento cognitivo, linguagem expressiva, motor fino e grosso. Métodos: Estudo quantitativo, transversal, exploratório, com 103 crianças de 24 a 42 mes
J. Pediatr. (Rio J.). Publicado em: 2020-06
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6. Crystal Structure and 1H NMR Experimental and Theoretical Study of Conformers of 5-Methyl-1-(4’-methylphenylsulfonylamino)-1H-[1,2,3]-triazole-4-carboxylic Acid Ethyl Ester and 5-Methyl-1-(phenylsulfonylamino)-1H-[1,2,3]-triazole-4-carboxylic Acid Ethyl Ester
We reported experimental and theoretical investigation of conformers of 1,2,3-triazole derivatives, substances of exclusively synthetic origin, subject of extensive studies, because of several biological properties, such as antiviral, antimicrobial and antileishmaniasis. We reported molecular/supramolecular X-ray structures of antiophidian compounds I and II
J. Braz. Chem. Soc.. Publicado em: 2020-05
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7. TD-DFT Analysis of the Dissymmetry Factor in Camphor
The fact that the dissymmetry lgeb (g-factor) of camphor is large has been known for decades, and the interpretation of the observed data has also been known for a long time. However, due to the ability of quantum chemical methods to describe chiroptical phenomena more appropriately, additional approaches based on these methods have been successful employed.
J. Braz. Chem. Soc.. Publicado em: 2020-03
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8. Food resource partitioning among species of Astyanax (Characiformes: Characidae) in the Lower Iguaçu River and tributaries, Brazil
RESUMO O particionamento de recursos permite a coexistência interespecífica e é frequentemente relatado para espécies semelhantes. Predizemos a existência de partição de recursos entre espécies de Astyanax que co-ocorrem no baixo rio Iguaçu. O total de 848 estômagos de cinco espécies de Astyanax foi analisado. Algas, plantas terrestres e frutos/se
Neotrop. ichthyol.. Publicado em: 25/11/2019
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9. Cardiorespiratory and metabolic determinants during moderate and high resistance exercise intensities until exhaustion using dynamic leg press: comparison with critical load
The objective of this study was to assess cardiovascular, respiratory, and metabolic responses during a commonly used dynamic leg press resistance exercise until exhaustion (TEx) at different intensities and compare with critical load (CL). This was a prospective, cross-sectional, controlled, and crossover study. Twelve healthy young men (23±2.5 years old)
Braz J Med Biol Res. Publicado em: 11/10/2018
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10. Brazoides A-D, New Alkaloids from Justicia gendarussa Burm. F. Species
Four new alkaloids, Brazoides A-D, together with three known compounds squalene, β-sitosterol and lupeol, were isolated from leaves of Justicia gendarussa. These structures were established by spectrometric techniques, mainly high-resolution electrospray ionization mass spectrometry (HRESIMS) and 1D and 2D nuclear magnetic resonance (NMR), including compara
J. Braz. Chem. Soc.. Publicado em: 2017-07
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11. Theoretical Study of Molecular and Electronic Structures of 51Knot Systems: Two‑Layered ONIOM Calculations
In this study we examine the electronic and molecular structures of the [51 knot···(PF6)10]+ pentafoil knot system and report calculated interaction energies that result from halides (X = F, Cl, Br, and I) localized at the center of the [51knot···(PF6)9]X molecular structure. The equilibrium geometries were fully optimized at the ONIOM(M06/6-31G(2d,p):
J. Braz. Chem. Soc.. Publicado em: 2015-05
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12. Comparative Analysis of Ck- and C0-GFEM Applied to Two-dimensional Problems of Confined Plasticity
AbstractFor many practical applications in engineering, a complex structure shows linear elastic behavior over almost all its extension, but exhibits confined plasticity contained in some small critical regions, e.g. stress concentrations in fillets and sharp internal corners. The behavior of C0- and Ck-GFEM is investigated in this class of problems. The fir
Lat. Am. j. solids struct.. Publicado em: 2015-05