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Search Results: 1 - 10 of 153148 matches for " Josinete B. Vieira "
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Evaluation of Quantum Chemical Methods and Basis Sets Applied in the Molecular Modeling of Artemisinin  [PDF]
Cleydson B. R. dos Santos, Cleison C. Lobato, Josinete B. Vieira, Davi S. B. Brasil, Alaan U. Brito, Williams J. C. Macêdo, José Carlos T. Carvalho, José C. Pinheiro
Computational Molecular Bioscience (CMB) , 2013, DOI: 10.4236/cmb.2013.33009
Abstract: In this paper, we evaluate semiempirical methods (AM1, PM3, and ZINDO), HF and DFT (B3LYP) in different basis sets to determine which method best describes the sign and magnitude of the geometrical parameters of artemisinin in the region of the endoperoxide ring compared to crystallographic data. We also classify these methods using statistical analysis. The results of PCA were based on three main components, explaining 98.0539% of the total variance, for the geometrical parameters C3O13, O1O2C3, O13C12C12a, and O2C3O13C12. The DFT method (B3LYP) corresponded well with the experimental data in the hierarchical cluster analysis (HCA). The experimental and theoretical angles were analyzed by simple linear regression, and statistical parameters (correlation coefficients, significance, and predictability) were evaluated to determine the accuracy of the calculations. The statistical analysis exhibited a good correlation and high predictive power for the DFT (B3LYP) method in the 6-31G** basis set.
A SAR and QSAR Study of New Artemisinin Compounds with Antimalarial Activity
Cleydson Breno R. Santos,Josinete B. Vieira,Cleison C. Lobato,Lorane I. S. Hage-Melim,Raimundo N. P. Souto,Clarissa S. Lima,Elizabeth V. M. Costa,Davi S. B. Brasil,Williams Jorge C. Macêdo,José Carlos T. Carvalho
Molecules , 2014, DOI: 10.3390/molecules19010367
Abstract: The Hartree-Fock method and the 6-31G** basis set were employed to calculate the molecular properties of artemisinin and 20 derivatives with antimalarial activity. Maps of molecular electrostatic potential (MEPs) and molecular docking were used to investigate the interaction between ligands and the receptor (heme). Principal component analysis and hierarchical cluster analysis were employed to select the most important descriptors related to activity. The correlation between biological activity and molecular properties was obtained using the partial least squares and principal component regression methods. The regression PLS and PCR models built in this study were also used to predict the antimalarial activity of 30 new artemisinin compounds with unknown activity. The models obtained showed not only statistical significance but also predictive ability. The significant molecular descriptors related to the compounds with antimalarial activity were the hydration energy (HE), the charge on the O11 oxygen atom (QO11), the torsion angle O1-O2-Fe-N2 (D2) and the maximum rate of R/Sanderson Electronegativity (RTe +). These variables led to a physical and structural explanation of the molecular properties that should be selected for when designing new ligands to be used as antimalarial agents.
Gerencia y política social: análisis de su relación, desarrollo y evaluación con énfasis en el gobierno de rafael caldera (1993-1998)
José Gregorio Vieira B.
Revista Venezolana de Análisis de Coyuntura , 2004,
Abstract: El presente artículo tiene como objetivo central, profundizar la reflexión en torno al análisis de la Gerencia social y la política social desarrollada fundamentalmente en el segundo gobierno de Rafael Caldera. La razón fundamental de centrar los esfuerzos en este período gubernamental, radica en que es precisamente en este período (1993-1998) cuando se continúa y fortalece el modelo de política social que se inicia con la aplicación del VIII Plan de la Nación en el segundo gobierno de Carlos Andrés Pérez, el cual se refiere a un tipo de política social de tipo compensa-toria, remedial y asistencialista, orientada hacia el ataque de la pobreza, a través de la focaliza-ción. Por tanto, el estudio de la relación y desarrollo de estos elementos en este período adquiere importancia, en la medida que se constituye en el antecedente más inmediato en mate-ria de política social del gobierno que se inicia posterior a Rafael Caldera.
A new class of phthalimido-quinones synthesis Síntese de uma nova classe de ftalimido-quinonas
Jeziane S. Alves,Josinete A. Paz,Celso A. Camara
Orbital : the Electronic Journal of Chemistry , 2012,
Abstract: Four new Michael adducts from the reaction between 1,4-naphthoquinone and 2,3-dibromo-1,4-naphthoquinone with w-amino-N-alkylphthalamide derivatives were presented in this work. The products named 2a-c were completed assigned on the basis of 13C, 1HNMR, IR and elemental analysis, still remaining spectroscopy data of 3a product (n=4). The global yields of 2a-c (n=3, 4 e 6) and 3a(n=4), was respectively 41%, 39 %, 27% and 30%.The yields are low probably due the formation of dimeric by-products. A new methodology has been employed to obtain the key-intermediates w-amino-N-alkylphthalamide (4a-b), using bromide alkylphthalamide (6a-b) (n=3-4) to obtain the corresponding azides (5a-b) with 85% and 90% yields, followed by catalytic hydrogenation with the use of palladium on charcoal 10% to obtain w-amino-N-alkylphthalamide (4a-b) with respectively 90% e 60% yields, as a more viable synthesis route. O presente trabalho apresenta a síntese de quatro compostos inéditos a partir da adi o de Michael à 1,4-naftoquinona e à 2,3-dibromo-1,4-naftoquinona a partir de w-amino-N-alquilftalimidas (n=3,4 e 6). Os produtos 2a-c já foram elucidados através das técnicas espectroscópicas de Infravermelho, RMN 1H, RMN 13C e análise elementar, restando ainda os dados espectroscópicos do produto 3a (n=4). Os rendimentos globais dos produtos 2a-c (n=3, 4 e 6) e 3a (n=4) foram 41%, 39%, 27%, e 30%, respectivamente. Os rendimentos s o baixos, visto que na primeira etapa, há a forma o de um produto dimérico. Diante disso, uma nova metodologia tem sido empregada para obten o dos intermediários-chave w-amino-N-alquilftalimidas (4a-b). A partir de alquil-ftalimidas bromadas (6a-b) (n=3-4), obtêm-se as azidas (5a-b) (n=3-4) com rendimento de 85% e 90% respectivamente, seguida da rea o de hidrogena o catalítica por meio de paládio/carbono (10%) para obten o de w-amino-N-alquilftalimidas com rendimento de 90% e 60%, respectivamente, o que tornará mais viável a síntese das moléculas-alvo.
A new class of phtalimido-quinones sinthesys Síntese de uma nova classe de ftalimido-quinonas
Jeziane S. Alves,Josinete A. Paz,Celso A. Camara
Orbital : the Electronic Journal of Chemistry , 2012,
Abstract: Four new Michael adducts from the reaction between 1,4-naphthoquinone and 2,3-dibromo-1,4-naphthoquinone with w-amino-N-alkylphthalamide derivatives were presented in this work (Scheme 1). The products named 2a-c were completed assigned on the basis of 13C, 1HNMR, IR and elemental analysis, still remaining spectroscopy data of 3a product (n=4). The global yields of 2a-c (n=3, 4 e 6) and 3a(n=4), was respectively 41%, 39 %, 27% and 30%.The yields are low probably due the formation of dimeric by-products. A new methodology has been employed to obtain the key-intermediates w-amino-N-alkylphthalamide (4a-b), using bromide alkylphthalamide (6a-b) (n=3-4) to obtain the corresponding azides (5a-b) with 85% and 90% yields, followed by catalytic hydrogenation with the use of palladium on charcoal 10 % to obtain w-amino-N-alkylphthalamide (4a-b) with respectively 90% e 60% yields, as a more viable synthesis route. O presente trabalho apresenta a síntese de quatro compostos inéditos a partir da adi o de Michael à 1,4-naftoquinona e à 2,3-dibromo-1,4-naftoquinona a partir de w-amino-N-alquilftalimidas (n=3,4 e 6) (Esquema 1). Os produtos 2a-c já foram elucidados através das técnicas espectroscópicas de Infravermelho, RMN 1H, RMN 13C e análise elementar, restando ainda os dados espectroscópicos do produto 3a (n=4). Os rendimentos globais dos produtos 2a-c (n=3, 4 e 6) e 3a (n=4) foram 41%, 39%, 27%, e 30%, respectivamente. Os rendimentos s o baixos, visto que na primeira etapa, há a forma o de um produto dimérico. Diante disso, uma nova metodologia têm sido empregada para obten o dos intermediários-chave w-amino-N-alquilftalimidas (4a-b). A partir de alquil-ftalimidas bromadas (6a-b) (n=3-4), obtêm-se as azidas (5a-b) (n=3-4) com rendimento de 85% e 90%, respectivamente, seguida da rea o de hidrogena o catalítica por meio de paládio/carbono (10%) para obten o de w-amino-N-alquilftalimidas com rendimento de 90% e 60%, respectivamente, o que tornará mais viável a síntese das moléculas-alvo.
A radial version of the Kontorovich-Lebedev transform in the unit ball
Semyon B. Yakubovich,Nelson Vieira
Opuscula Mathematica , 2011,
Abstract: In this paper we introduce a radial version of the Kontorovich-Lebedev transform in the unit ball. Mapping properties and an inversion formula are proved in $L_p$
Saul bellow's henderson, the rain king — a coming to terms with his self and with the world around Saul bellow's henderson, the rain king — a coming to terms with his self and with the world around
Myrian Vieira B. de Oliveira
Ilha do Desterro , 2008,
Abstract: As the plot focuses on Henderson, our starting point wil be a presentation of his most important characteristics, so we can better understand the developing of the action. Henderson, at the age of fifty-five, is not a happy man. Although he has a nice wife and kids, plenty of money and time to enjoy life and its pleasures, he thinks he has made a mess of his life. Physically, he describes himself as "six feet four inches tall. Two hundred and thirty pounds - An enormous head, rugged, with hair like Persian lamb's fur. Suspicious eyes, usually narrowed. Blustering ways. A great nose" (p.8). His appearance is, to say the least, remarkable. And he made it still more remarkable by the kind of clothes he liked to wear. He is a person who requires " large and real emotions" (p. 25) and that is why he was happy when he was in the war; /the civilian life bored him. Although he is always quarreling and many times "behaved like a bum", he wants to belong, to be accepted. On p. 256, when he's telling about one of his experiences with king Dahfu, what kind of words came instinctively from his mouth? "and certain words crept into my roars, like "God", "Help", "Lord Have Mercy"... plus snatches from the Messiah (he was despised and rejected, a man of sorrows, etcetera". He feels there is a similarity between the Messiah and himself. Another aspect of his contradictory personality is the combination of sensitivity and a taste for hard manual work. The same hands that have"thrown down boars and pinned them and gelded them" (p. 32) also played the violin. As the plot focuses on Henderson, our starting point wil be a presentation of his most important characteristics, so we can better understand the developing of the action. Henderson, at the age of fifty-five, is not a happy man. Although he has a nice wife and kids, plenty of money and time to enjoy life and its pleasures, he thinks he has made a mess of his life. Physically, he describes himself as "six feet four inches tall. Two hundred and thirty pounds - An enormous head, rugged, with hair like Persian lamb's fur. Suspicious eyes, usually narrowed. Blustering ways. A great nose" (p.8). His appearance is, to say the least, remarkable. And he made it still more remarkable by the kind of clothes he liked to wear. He is a person who requires " large and real emotions" (p. 25) and that is why he was happy when he was in the war; /the civilian life bored him. Although he is always quarreling and many times "behaved like a bum", he wants to belong, to be accepted. On p. 256, when he's telling about one of his experiences
Deteriora??o controlada para avaliar o potencial fisiológico de sementes de beterraba
Silva, Josué B;Vieira, Roberval D;
Horticultura Brasileira , 2012, DOI: 10.1590/S0102-05362012000300004
Abstract: seeds of vegetable crop species always present high commercial value, so the physiological potential must be efficiently evaluated. the controlled deterioration is a recommended test to evaluate seed vigor of small-seeded vegetable crops, such as beetroot seeds. this research was run in order to determine the best controlled deterioration test procedures for beetroot seeds and its relationship with field seedling emergence. seven commercial seed lots of the cultivar top tall early wonder were used. after washing in running water, the seeds were tested for germination, speed of germination, accelerated aging, seedling field emergence, emergence rate and controlled deterioration (41 and 45°c, moisture contents of 22, 24 and 26% and exposure times of 12, 24 and 36 hours). the combination of 41°c/24%/12 hours, 41°c/24%/36 hours, 41°c/26%/36 hours and 45°c/24%/24 hours showed potential to evaluate vigor of beetroot seeds. however, the combinations of 41°c/24%/12 hours or 45°c/24%/24 hours decreased the conduction time of the test.
A irriga??o por gotejamento em berinjela (Solanum melongena, L.)
Vieira, D. B.;Manfrinato, H. A.;
Anais da Escola Superior de Agricultura Luiz de Queiroz , 1974, DOI: 10.1590/S0071-12761974000100006
Abstract: this work shows the data of a field experiment of drip irrigation for the egg plant in comparison to the furrow irrigation. the drip irrigation was applied in three different intensities: low, medium and high. the obtained data indicated better results for the drip irrigation method.
Lagrangian formulation of Newtonian cosmology
H. S. Vieira,V. B. Bezerra
Physics , 2014, DOI: 10.1590/S1806-11172014000300010
Abstract: In this paper, we use the Lagrangian formalism of classical mechanics and some assumptions to obtain cosmological differential equations analogous to Friedmann and Einstein equations, obtained from the theory of general relativity. This method can be used to a universe constituted of incoherent matter, that is, the cosmologic substratum is comprised of dust.
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