955 resultados para Anti-ADN topoisomérase I


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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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This article presents some aspects of the relationship between the philosophies of Frege and Stuart Mill, from the standpoint of the fregean critic of psychologism and empiricism. I defend the thesis that, in Foundations of Arithmetic, Frege directs his criticism to the empiricism professed by Mill in his System of Logic; this critic does not constitutes a ‘charge’ of the English philosopher as being a psychologist. For this, we presented several aspects concerning the role that the antipsicologismo has in the Fregean thought and its direct relationship with the logicist project of reduction of arithmetic to logic. To defend our thesis, some arguments intended to show that empiricism not necessarily and directly imply psychologism are presented.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Este trabalho visa o estudo dos efeitos biológicos dos extratos hidroalcóolicos (HDA) obtidos das cascas e folhas de Astronium fraxinifolium (Anacardiaceae), uma espécie medicinal do Cerrado brasileiro. Com base nas indicações populares de uso da espécie no combate a diversos males como a diarréia, cólicas, inflamação e reumatismo e a confirmação pela literatura da atividade gastroprotetora da espécie congênere Astronium urundeuva, foram realizados modelos experimentais in vivo para caracterizar a propriedade anti-úlcera, antidiarrêica e antiinflamatória dos extratos hidroalcóolicos de cascas (A.f.cs) e folhas (A.f.fol) de A. fraxinifolium. A propriedade antiulcerogênica dos A.f.cs e A.f.fol, administrado pela via oral, em diferentes doses (125, 250 e 500 mg/kg) foi avaliada em modelos experimentais in vivo em que os ratos Wistar machos foram confrontados com agentes ulcerogênicos químicos como etanol absoluto e droga antiinflamatória não-esteroidal (DAINE). Os fatores envolvidos na gastroproteção dos extratos foram avaliados através da quantificação de glutationa total do raspado da mucosa, volume do suco gástrico, concentração de íons H+ e pH do suco gástrico. A atuação de fatores protetores da mucosa gástrica como óxido nítrico (NO) e compostos sulfidrílicos (SH) também foram analisados sob efeito de ambos os extratos. A propriedade antidiarrêica dos extratos (500 mg/kg, p.o.) também foi avaliada através da motilidade intestinal, índice de evacuações e acumulo de fluidos intestinais. Ambos os extratos (500 mg/kg, p.o. e 50 mg/kg, i.p.) também foram submetidos a avaliação em dois modelos experimentais (edema da pata induzida por carragenina e teste de formalina) onde as propriedades antiedematogênica e antiinflamatória foram analisadas em roedores. Ambos os extratos foram estudos fitoquimicamente em CLAE-DAE... (Resumo completo, clicar acesso eletrônico abaixo)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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ln order to predict the facial growth using Jarahak's analysis, cephalometric radiographies of 120 subjects during the mixed dentition and between 6 and 10 years of age were studied. From the total, 60 subjects (30 males and 30 females) were classified as Angle's Class I and 60 subjects (30 males and 30 females) were classified as Angle's Class II, Division 1. AIl subjects did not receive any orthodontic treatment. The proportion between anterior and posterior facial heigth (SGo-NMe) was studied, which is determined by the formula PFH x 100/ AFH = %, neither being straight (> 62% < 65), clockwise ( > 58% < 62%) and anti-clockwise ( > 65% - 80%). Mean average, standard deviation and facial height proportion (SGo - NMe) were determined for males and females according to Angle's classification of malocc!usion. Sexual dimorphism was examined with regard to different types of Angle's malocclusion and the direction of the facial growth, and the correlation of four cephalometrics measurements were analvsed

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Ozone, first discovered in the mid 1800’s, is a triatomic allotrope of oxygen that is a powerful oxidant. For over a century, research has been conducted into the synthetic application and mechanism of reactions of ozone with organic compounds. One of the major areas of interest has been the ozonolysis of alkenes. The production of carbonyl compounds is the most common synthetic application of ozonolysis. The generally accepted mechanism developed by Rudolf Criegee for this reaction involves the 1,3-electrocyclic addition of ozone to the π bond of the alkene to form a 1,2,3-trioxolane or primary ozonide. The primary ozonide is unstable at temperatures above -100 °C and undergoes cycloreversion to produce the carbonyl oxide and carbonyl intermediates. These intermediates then recombine in another 1,3-electrocyclic addition step to form the 1,2,4-trioxolane or final ozonide. While the final ozonide is often isolable, most synthetic applications of ozonolysis require a subsequent reductive or oxidative step to form the desired carbonyl compound. During investigations into the nucleophilic trapping of the reactive carbonyl oxide, it was discovered that when amines were used as additives, an increased amount of reaction time was required in order to consume all of the starting material. Surprisingly, significant amounts of aldehydes and a suppression of ozonide formation also occurred which led to the discovery that amine N-oxides formed by the ozonation of the amine additives in the reaction were intercepting the carbonyl oxide. From the observed production of aldehydes, our proposed mechanism for the in situ reductive ozonolysis reaction with amine N-oxides involves the nucleophilic trapping of the carbonyl oxide intermediate to produce a zwitterionic adduct that fragments into 1O2, amine and the carbonyl thereby avoiding the formation of peroxidic intermediates. With the successful total syntheses of peroxyacarnoates A and D by Dr. Chunping Xu, the asymmetric total synthesis of peroxyplakorate A3 was investigated. The peroxyplakoric acids are cyclic peroxide natural products isolated from the Plakortis species of marine sponge that have been found to exhibit activity against malaria, cancer and fungi. Even though the peroxyplakorates differ from the peroxyacarnoates in the polyunsaturated tail and the head group, the lessons learned from the syntheses of the peroxyacarnoates have proven to be valuable in the asymmetric synthesis of peroxyplakorate A3. The challenges for the asymmetric synthesis of peroxyplakorate A3 include the stereospecific formation of the 3-methoxy-1,2-dioxane core with a propionate head group and the introduction of oxidation sensitive dienyl tail in the presence of a reduction sensitive 1,2-dioxane core. It was found that the stereochemistry of two of the chiral centers could be controlled by an anti-aldol reaction of a chiral propionate followed by the stereospecific intramolecular cyclization of a hydroperoxyacetal. The regioselective ozonolysis of a 1,2-disubstituted alkene in the presence of a terminal alkyne forms the required hydroperoxyacetal as a mixture of diastereomers. Finally, the dienyl tail is introduced by a hydrometallation/iodination of the alkyne to produce a vinyl iodide followed by a palladium catalyzed coupling reaction. While the coupling reaction was unsuccessful in these attempts, it is still believed that the intramolecular cyclization to introduce the 1,2-dioxane core could prove to be a general solution to many other cyclic peroxides natural products.