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Search Results: 1 - 10 of 227036 matches for " Cláudio N. Alves "
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Levels of As, Cd, Pb and Hg found in the hair from people living in Altamira, Pará, Brazil: environmental implications in the Belo Monte area
Carvalho, Antonio S. C.;Santos, Alberdan S.;Pereira, Simone F. P.;Alves, Cláudio N.;
Journal of the Brazilian Chemical Society , 2009, DOI: 10.1590/S0103-50532009000600022
Abstract: human hair was used as a bioindicator to evaluate the levels of as, cd, pb and hg in the resident population of the "volta grande" area of the xingu river, in the north of brazil. the concentrations of as and cd are in agreement with the values found in the literature, however, the pb and hg concentration is very different, which can suggest an inter-regional variation. moreover, the high values found for these elements in the residents of the canteiro island can be attributed to environmental exposure of this population in an area with environmental impact from activities of gold mining. the application of these methods showed that the concentrations of the metals studied in this work can correctly classify two different localities in the altamira district. the results reflect the impact of these elements on the health of the inhabitants of this auriferous area.
Biotransformation of sucrose into 5-hydroxy-2-hydroxymethyl-γ-pirone by Aspergillus flavus
Ferreira, Nelson R.;Sarquis, Maria Inez M.;Alves, Cláudio N.;Santos, Alberdan S.;
Anais da Academia Brasileira de Ciências , 2010, DOI: 10.1590/S0001-37652010000300004
Abstract: the sucrose hydrolysis and the preference of consumption of glucose instead of fructose were investigated for the production of 5-hydroxy-2-hydroxymethyl-γ-pyrone (hhmp) in the presence of aspergillus flavus ioc 3974 cultivated in liquid czapeck medium. standardized 0.5g of pellets were transferred as inoculum into twelve conical flasks of 250 ml containing 100 ml of medium with different sucrose concentration, which was kept at 120 rpm and 28"c for 16 days without ph adjustment. aliquots of 500μl of the broth culture were withdrawn at 24 h intervals and analyzed. the major yield of hhmp was 26g l-1 in 120g l-1 of sucrose. at these conditions, a. flavus produced an invertase capable of hydrolyzing 65% of total sucrose concentration in 24h, and an isomerase capable of converting fructose into glucose. in this work, it focused the preference for glucose and, then, of fructose by a. flavus and the strategy used to produce hhmp.
Structure of Dihydrochalcones and Related Derivatives and Their Scavenging and Antioxidant Activity against Oxygen and Nitrogen Radical Species
Alexandre L. A. Bentes,Rosivaldo S. Borges,Waldinei R. Monteiro,Luiz G. M. De Macedo,Cláudio N. Alves
Molecules , 2011, DOI: 10.3390/molecules16021749
Abstract: Quantum mechanical calculations at B3LYP/6-31G** level of theory were employed to obtain energy (E), ionization potential (IP), bond dissociation enthalpy (O-H BDE) and stabilization energies (DEiso) in order to infer the scavenging activity of dihydrochalcones (DHC) and structurally related compounds. Spin density calculations were also performed for the proposed antioxidant activity mechanism of 2,4,6-trihydroxyacetophenone (2,4,6-THA). The unpaired electron formed by the hydrogen abstraction from the phenolic hydroxyl group of 2,4,6-THA is localized on the phenolic oxygen at 2, 6, and 4 positions, the C3 and C6 carbon atoms at ortho positions, and the C5 carbon atom at para position. The lowest phenolic oxygen contribution corresponded to the ?highest scavenging activity value. It was found that antioxidant activity depends on the presence of a hydroxyl at the C2 and C4 positions and that there is a correlation between IP and O-H BDE and peroxynitrite scavenging activity and lipid peroxidation. These results identified the pharmacophore group for DHC.
Uma nova síntese de alfa-bromo-acetofenonas e sua aplica??o na obten??o de 2-benzoil-benzofuranas
Azevedo, Mariangela S.;Alves, Ana Paula L.;Alves, Glaucia B. C.;Cardoso, Jari N.;Lopes, Rosangela S. C.;Lopes, Cláudio C.;
Química Nova , 2006, DOI: 10.1590/S0100-40422006000600022
Abstract: a-bromoacetophenones are important in organic synthesis. they have been widely used as precursors of several natural products. several methods of bromination aiming at their synthesis have been described, however they furnish a mixture of starting material 10, mono 8 and dibromide 11 products. we developed a novel, simple and efficient synthesis of these compounds with applications in the synthesis of benzoylbenzofurans 9, compounds with important pharmacological properties, such as the ability of dilating the coronary artery and analgesic action. such compounds have also been used as key intermediates to obtain quinone systems.
Constitui??o, competi??o e políticas públicas
Couto, Cláudio Gon?alves;
Lua Nova: Revista de Cultura e Política , 2005, DOI: 10.1590/S0102-64452005000200005
Abstract: government decisions and constitutional rules have different status and meaning. while the former are about the political moment and the daily democratic game, the latter are about the frame of democracy itself, staying (in principle) outside the subjects of the ordinary decision-making process. this article focuses the ways the constitutional and democratic theories (within the field of political science) deal with that dicothomy.
A agenda constituinte e a difícil governabilidade
Couto, Cláudio Gon?alves;
Lua Nova: Revista de Cultura e Política , 1997, DOI: 10.1590/S0102-64451997000100004
Abstract: one of the main features of brazilian politics in the years following the end of the military regime has been the constitutionalization of the governmental agenda. forced to form wide coalizations which overstep the routine demand of absolute majority, the chiefs of the executive branch face greater difficulties than those which normally characterize presidentialist systems. besides a consociative political system brazil has been facing an ultraconsociative agenda.
Mudan?a e crise: o PT no governo em S?o Paulo
Couto, Cláudio Gon?alves;
Lua Nova: Revista de Cultura e Política , 1994, DOI: 10.1590/S0102-64451994000200011
Abstract: the text examines through a case study how a change in the organizational environment in which a political party acts transforms its ways of political action, including its relationships with representative institutions like the parliament.
A Longa Constituinte: Reforma do Estado e Fluidez Institucional no Brasil
Couto, Cláudio Gon?alves;
Dados , 1998, DOI: 10.1590/S0011-52581998000100002
Abstract: the article discusses the process of political and economic transition in brazil since the close of the constitutional congress. addressing the question from an institutionalist perspective, it is argued that these two dimensions of the transition are not the only ones which should be considered in conjunction; a series of other factors must be taken into account as well. first is the question of the sequential chain within the transition process: policies enacted at a given moment depend upon circumstances generated earlier, both in content and in form, creating a relation of path-dependence. second, this constraint holds greater sway during a transition period, given the fluid conditions under which politics are played out: the political climate and institutions change over time. third, the actors go through a process of institutional learning, which means the same institutional structures are not operated in the same fashion at different moments. it is necessary to devise a dynamic model for analyzing brazil's political system during this period. more valuable than any static model would be an analysis of the process which takes into account the intermixing of different political agendas (simultaneously and sequentially), institutional fluidity, and environmental transformations.
O avesso do avesso: conjuntura e estrutura na recente agenda política brasileira
COUTO, CLáUDIO GON?ALVES;
S?o Paulo em Perspectiva , 2001, DOI: 10.1590/S0102-88392001000400005
Abstract: fernando henrique cardoso implementou sua agenda governamental utilizando, simultanea e articuladamente, diversos mecanismos decisórios. destacam-se as medidas provisórias e as emendas constitucionais. converteram-se umas ? concebidas para emergências conjunturais ? em instrumentos legislativos corriqueiros, por isso mesmo estruturais; e outras ? feitas para modificar a estrutura institucional perene de nosso sistema político ? em instrumentos de implementa??o das políticas particulares de um governo particular, por isso mesmo conjunturais.
The Future Air Navegation System (FANS)
Cláudio Jorge Pinto Alves
Transportes , 2010,
Abstract:
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