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Search Results: 1 - 10 of 381863 matches for " Alessandra R. P.;Mafezoli "
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New Pyrone and Quinoline Alkaloid from Almeidea rubra and their Trypanocidal Activity
Alessandra R. P. Ambrozin,Jair Mafezoli,Paulo C. Vieira,Jo?o B. Fernandes
Revista de la Sociedad Química de México , 2005,
Abstract: The investigation of the ethyl acetate fraction of methanol extract from leaves of Almeidea rubra A. St.-Hil. (Rutaceae) afforded two new compounds 4-methoxy-6-[2-(methylamino)phenyl]-2Hpyran- 2-one and rel-(7R,8R)-8-[(E)-3-hydroxy-3-methyl-1-butenyl]-4,8-dimethoxy-5,6,7,8- tetrahydrofuro[2,3-b]quinoline-7-yl acetate, along with the known compounds arborinine, N-methyl- 1-hydroxy-3-methoxyacridone, skimmianine, kokusagine, isodutaduprine, isoskimmianine, and isokokusagine. Their structures were established based on their spectral data, and for the new compounds these data are described herein. Additionally, these compounds were assayed on the tripomastigote forms of Trypanosoma cruzi showing moderate trypanocidal activity.
New pyrone and quinoline alkaloid from Almeidea rubra and their trypanocidal activity
Ambrozin, Alessandra R. P.;Mafezoli, Jair;Vieira, Paulo C.;Fernandes, Jo?o B.;Silva, M. Fátima das G. F. da;Ellena, Javier A.;Albuquerque, Sérgio de;
Journal of the Brazilian Chemical Society , 2005, DOI: 10.1590/S0103-50532005000300018
Abstract: the investigation of the ethyl acetate fraction of methanol extract from leaves of almeidea rubra a. st.-hil. (rutaceae) afforded two new compounds 4-methoxy-6-[2-(methylamino)phenyl]-2h-pyran-2-one and rel-(7r,8r)-8-[(e)-3-hydroxy-3-methyl-1-butenyl]-4,8-dimethoxy-5,6,7,8 -tetrahydrofuro[2,3-b]quinoline-7-yl acetate, along with the known compounds arborinine, n-methyl-1-hydroxy-3-methoxyacridone, skimmianine, kokusagine, isodutaduprine, isoskimmianine, and isokokusagine. their structures were established based on their spectral data, and for the new compounds these data are described herein. additionally, these compounds were assayed on the tripomastigote forms of trypanosoma cruzi showing moderate trypanocidal activity.
Fatty acids and terpenoids from Trigonia fasciculata
Mafezoli, Jair;Santos, Regina Helena A.;Gambardela, Maria Teresa P.;Silveira, Edilberto R.;
Journal of the Brazilian Chemical Society , 2003, DOI: 10.1590/S0103-50532003000300011
Abstract: the fatty portion of the hexane extract from roots of trigonia fasciculata has been determined by gc/ms analysis of the methyl ester mixture. seventeen fatty acids were identified and oleic acid (38.8%) was the major component. the gc/ms analysis of the less polar fraction of the non-saponifiable part of the root hexane extract allowed the identification of fifteen sesquiterpenes and a-santalene (28.4%) was the major component. chromatography over silica gel of the more polar fraction allowed the isolation of two known compounds: betulinic acid and friedelin, and a novel diterpene 7-(2-hydroxy-acetyl)-10-hydroxy-tetradecahydro-1-methylene-4b,7,10a-trimethyl -phenantrene (6a-hydroxy-15-oxo-allodevadarool), all unknown for the species. structure determination was accomplished by chemical derivatization, comparison to literature data and spectral analysis, including 2d nmr (cosy, hetcor, coloc) and x-ray crystallography.
Fatty acids and terpenoids from Trigonia fasciculata
Mafezoli Jair,Santos Regina Helena A.,Gambardela Maria Teresa P.,Silveira Edilberto R.
Journal of the Brazilian Chemical Society , 2003,
Abstract: The fatty portion of the hexane extract from roots of Trigonia fasciculata has been determined by GC/MS analysis of the methyl ester mixture. Seventeen fatty acids were identified and oleic acid (38.8%) was the major component. The GC/MS analysis of the less polar fraction of the non-saponifiable part of the root hexane extract allowed the identification of fifteen sesquiterpenes and alpha-santalene (28.4%) was the major component. Chromatography over silica gel of the more polar fraction allowed the isolation of two known compounds: betulinic acid and friedelin, and a novel diterpene 7-(2-hydroxy-acetyl)-10-hydroxy-tetradecahydro-1-methylene-4b,7,10a-trimethyl -phenantrene (6alpha-hydroxy-15-oxo-allodevadarool), all unknown for the species. Structure determination was accomplished by chemical derivatization, comparison to literature data and spectral analysis, including 2D NMR (COSY, HETCOR, COLOC) and X-ray crystallography.
Efeito da desnutri??o protéica pré e pós-natal sobre a morfologia, a diferencia??o e o metabolismo do tecido muscular estriado esquelético em ratos
Alves, Alessandra P.;Damaso, Ana R.;Dal Pai, Vitalino;
Jornal de Pediatria , 2008, DOI: 10.1590/S0021-75572008000300013
Abstract: objective: to study the contractile properties, metabolism and morphological characteristics of muscles submitted to prenatal and postnatal protein malnutrition. methods: animals were distributed into two groups: control, normoprotein diet (cg; n = 15; 5/5/5), and malnourished, hypoprotein diet (mg; n = 15; 5/5/5), and examined on the 7th, 14th, and 28th days of the experiment. total body mass, weight, and the contractile properties and morphology of the anterior tibial muscle were assessed. several 8 μm-thick tissue samples were taken from 7, 14, and 28 day old rats and stained with he or subjected to nadh-tr or m-atpase (ph = 4.4) techniques. results: body and muscle weight were lower in the malnourished group. on the 7th day of malnutrition, muscle samples exhibited fibers with smaller diameter, higher polymorphism and higher endomysial conjunctive tissue content. histochemical methods were unable to precisely determine the types of fiber present. on the 14th day, there were smaller muscle fibers, more polymorphism, many of them with central nuclei and moderate endomysial conjunctive tissue content. with reference to contractile properties, the m-atpase reaction identified both slow and fast fibers. the nadh-tr reaction revealed the following types of fiber: slow oxidative (so), fast oxidative glycolytic (fog) and fast glycolytic (fg). on the 28th day smaller, bunched muscle fibers varying shapes. all three types of fiber exhibited unclear recognition limits with respect to contraction and metabolism. conclusion: our experimental results suggest that, in addition to the reduction in numbers of fibers, malnutrition retards the differentiation of the morphological, metabolic, and contractile characteristics of skeletal muscle fibers in growing rats.
Influência de cortes na cultura da alfafa (Medicago sativa) sobre a flutua??o populacional de ninfas e adultos de pulg?es (Homoptera: Aphididae)
Carvalho, Alessandra R.;Mendes, Simone;Bueno, Vanda H. P.;
Anais da Sociedade Entomológica do Brasil , 1997, DOI: 10.1590/S0301-80591997000200007
Abstract: population dynamics of therioaphis trifolii (monell) forma maculata, acyrthosiphon kondoi shinji and acyrthosiphon pisum (harris) was studied in alfalfa (medicago sativa) crops for hay production at universidade federal de lavras, minas gerais, after 14 cuts, between march, 1993 and march, 1995. fall and winter were the most favorable seasons for the three species; t. trifolii f. maculata doubled its population from 1st to 2nd year, a. pisum and a. kondoi maintained the same population level. the number at the some age was similar to the three species of aphids, ranging from 64% to 78% for nynphs of the 1st and 2nd instars; from 18% to 26% for 3rd and 4th instars; and from 4% to 10% for adults. alate occurred in low densities (15%) compared to nymphs of 3rd and 4th instars and adults, always associated to high population densities. there was an overall decrease in the populations of aphids after each cutting, followed by a recovery associated with the development of plants and weather conditions.
Compara??o de técnicas para cria??o de Diabrotica speciosa (Germar) (Coleoptera: Chrysomelidae) em dietas natural e artificial
ávila, Crébio J.;Tabai, Alessandra Cristina P.;Parra, José R. P.;
Anais da Sociedade Entomológica do Brasil , 2000, DOI: 10.1590/S0301-80592000000200007
Abstract: studies viewing the improvement of the rearing methodology of diabrotica speciosa (germar) (coleoptera: chrysomelidae) in laboratory were carried out. larval development was compared in three rearing methods, two of which with natural diet using corn seedlings kept on vermiculite or on germination paper sheets and a third system using artificial diet. the following biological parameters were evaluated: duration and viability of the larva-adult period; weight of newly emerged adults (male and female); duration of pre-oviposition and oviposition periods; male and female longevity and fecundity. the development of the insect under different larval densities (100, 200, 400 and 600 larvae), using the same amount of natural diet, (corn seedlings) was also evaluated. when the insects were reared on corn kept in wet vermiculite the viability of the larva-adult period was higher than when corn was kept on wet paper sheet; the opposite was observed with the length of the developmental period. females reared in artificial diet had lesser pre-oviposition and oviposition periods and laid less eggs than those reared in natural diet. the increase in the larval density extended the duration of the immature phases, decreased the viability of the larva-adult period and reduced the weight of adults. the rearing technique of d. speciosa using natural diet in vermiculite provided a large amount of insects, with a significant reduction in labor and laboratory space.
Mortalidade de larvas e pupas de Chrysomya megacephala (Fabricius) (Diptera: Calliphoridae) e seu parasitismo por microhimenópteros na cidade do Rio de Janeiro, RJ
Carvalho, Alessandra R. de;D?Almeida, José M.;Mello, Rubens P. de;
Neotropical Entomology , 2004, DOI: 10.1590/S1519-566X2004000400017
Abstract: devido à importancia de chrysomya megacephala (fabricius) como vetor de microrganismos patogênicos em grandes aglomera??es humanas, este trabalho teve por objetivo conhecer a mortalidade da mosca durante as fases larval e pupal e o seu parasitismo por microhimenópteros. larvas de c. megacephala de terceiro ínstar, juntamente com seu substrato de cria??o (carne bovina moída putrefata), foram colocadas por sete dias próximo a lixeiras, no campus do instituto oswaldo cruz /fiocruz e no jardim zoológico do rio de janeiro, rio de janeiro, rj, de agosto de 1999 a julho de 2000. as pupas recolhidas após o período em campo foram individualizadas em cápsulas de gelatina e mantidas em camara climática (27°c) por aproximadamente 35 dias. foi verificado o número de pupas com emergência de moscas, com emergência de parasitóides e pupas sem emergência, sendo as últimas dissecadas. obteve-se mortalidade média de 29,6% durante a fase larval e pupal das moscas quando expostas ao ambiente externo, contra 16,5% do grupo controle. das pupas trazidas do campo, 5,6% estavam parasitadas, de 77,6% emergiram moscas e de 16,8% n?o houve emergência. tachinaephagus zealandicus ashmead (encyrtidae) mostrou-se um promissor inimigo natural de c. megacephala, com a maior percentagem de coloniza??o das pupas parasitadas (78,6%) e maior número médio de parasitóides por pupa (15,2). pachycrepoideus vindemiae rondani (pteromalidae) e nasonia vitripennis (walker) (pteromalidae), apresentaram menor percentagem de parasitismo que a primeira espécie, tanto no ioc como no zoológico, parasitando 13,2% e 8,2% das pupas, ambos com 1,0 e 11,1 parasitóides por pupa, em média, respectivamente.
Varia??es sazonais nas concentra??es de pigmentos e nutrientes em folhas de espécies de cerrado com diferentes estratégias fenológicas
Carvalho, Ana Paula F.;Bustamante, Mercedes M.C.;Kozovits, Alessandra R.;Asner, Gregory P.;
Brazilian Journal of Botany , 2007, DOI: 10.1590/S0100-84042007000100003
Abstract: several studies have been trying to establish relationships between environmental conditions and leaf traits. in the present study, concentrations of pigments (chlorophylls a, b, carotenoids and anthocyanins), n and p and specific leaf area (sla) were measured in leaves of six "cerrado" species (three deciduous and three evergreen species) in two cerrado stricto sensu sites with differences in canopy cover and in different periods: at the beginning of the dry season (june), end of dry season (september) and beginning of the rainy season (november). nutrient concentrations differed significantly as a function of phenology and seasonality while pigments were more sensitive to changes in vegetation structure. the highest chlorophyll a and b concentrations were measured at the beginning of the dry season (june) in comparison to the end of the dry season (september) in both sites. in june, chlorophyll a and b concentrations were higher in the denser cerrado while the chlorophyll a/b ratio was lower. total chlorophyll/carotenoids ratio was also significantly higher in the denser cerrado at the beginning of the dry season due to the higher chlorophyll concentration. deciduous species showed higher sla mean values than evergreen species, in dry and wet season but higher n and p concentrations were found in the evergreen species. in both phenological groups, n and p concentrations and the n:p ratios were higher in the wet season (november) than in the dry season (june).
Modelo numérico do terreno obtido por diferentes métodos em cartas planialtimétricas
Barbosa, Ana P.;Silva, Alessandra F. da;Zimback, Célia R. L.;
Revista Brasileira de Engenharia Agrícola e Ambiental , 2012, DOI: 10.1590/S1415-43662012000600010
Abstract: the digital elevation model is important to determine the slope and land use capability, therefore, a proposal of methodology for acquisition of elevation data contemplating an efficient algorithm to generate a slope map was developed. thus, it was aimed to obtain and evaluate a digital elevation model without the vetorization of the contours on planialtimetric charts. the area for acquisition of elevation data was s?o manuel, sp. the data were collected by two methods: level contour vetorization and the gathering of elevation points on the level contour with maximum elevation points. the elevation data were analyzed by geostatistical techniques. inspite of wide difference in the number of collected points between two methods, the variograms were adjusted to the exponential model and showed a range of approximately 1500 m, which does not justify the wide difficulty in vetorization of the planialtimetric charts, once the data points collected in the area were appropriately distributed, they represented rightly the terrain surface
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