Effects of hydroxyl group distribution on the reactivity, stability and optical properties of fullerenols

We investigate the impact of hydroxyl groups on the properties of C(60)(OH)(n) systems, with n = 1, 2, 3, 4, 8, 10, 16, 18, 24, 32 and 36 by means of first-principles density functional theory calculations. A detailed analysis from the local density of states has shown that adsorbed OH groups can induce dangling bonds in specific carbon atoms around the adsorption site. This increases the tendency to form polyhydroxylated fullerenes (fullerenols). The structural stability is analyzed in terms of the calculated formation enthalpy of each species. Also, a careful examination of the electron density of states for different fullerenols shows the possibility of synthesizing single molecules with tunable optical properties.

Reactivity of Beer Bitter Acids Toward the 1-Hydroxyethyl Radical as Probed by Spin-Trapping Electron Paramagnetic Resonance (EPR) and Electrospray Ionization-Tandem Mass Spectrometry (ESI-MS/MS)

The iso-alpha-acids or isohumulones are the major contributors to the bitter taste of beer, and it is well-recognized that they are degraded during beer aging. In particular, the trans-isohumulones seem to be less stable than the cis-isohumulones. The major radical identified in beer is the 1-hydroxyethyl radical; however, the reactivity between this radical and the isohumulones has not been reported until now. Therefore, we studied the reactivity of isohumulones toward the 1-hydroxyethyl radical through a competitive kinetic approach. It was observed that both cis- and trans-isohumulones and dihydroisohumulones are decomposed in the presence of 1-hydroxyethyl radicals, while the reactivities are comparable. On the other hand, the tetrahydroisohumulones did not react with 1-hydroxyethyl radicals. The apparent second-order rate constants for the reactions between the 1-hydroxyethyl radical and these compounds were determined by electron paramagnetic resonance (EPR) spectroscopy and electrospray ionization-tandem mass spectrometry [ESI(+)-MS/MS]. It follows that degradation of beer bitter acids is highly influenced by the presence of 1-hydroxyethyl radicals. The reaction products were detected by liquid chromatography electrospray ionization-ion trap-tandem mass spectrometry (LC-ESI-IT-MS/MS), and the formation of oxidized derivatives of the isohumulones was confirmed. These data help to understand the mechanism of beer degradation upon aging.

Eficiência operacional e inovação radical : fatores determinantes para uma organização inovadora

A globalização impõe às empresas a necessidade de flexibilizar, ter competência e inovar para continuarem no mercado, devido à transição de uma economia industrial para uma economia baseada no conhecimento. Esta economia exige das empresas rapidez nas decisões e vantagem competitiva sustentável, que só conseguem alcançar quando desenvolvem a capacidade de inovar de forma contínua. Este trabalho aborda os fatores organizacionais determinantes para uma empresa inovar de forma contínua, identificando como as estratégias de exploitation (eficiência operacional) e exploration (inovação radical) podem coexistir, visto que, por algum tempo, foram consideradas incompatíveis de serem adotadas simultaneamente. Devido à grande experiência profissional do autor deste trabalho, decidiu-se enfocar esses estudos na Motorola, empresa notadamente focada em inovação radical, como no advento do telefone celular, e também na melhoria da eficiência operacional, como no desenvolvimento do processo de melhoria Six-Sigma. Por meio de levantamento bibliográfico, estudo das fases de vida da empresa e aplicação de questionário aos funcionários da Motorola, chegou-se às seguintes conclusões: ratificou-se a importância da coexistência das duas estratégias, para que a empresa sustente a vantagem competitiva; esclareceu-se que tanto eficiência operacional quanto inovação radical são efeitos de uma organização inovadora. A causa primordial de uma empresa, como a Motorola, ser uma organização inovadora reside na condição de existir uma cultura de inovação que valoriza os funcionários, com um intento estratégico declarado de inovar, propiciando a geração de novas idéias, possuindo recursos e processos de modo que sejam gerados resultados econômicos dessas novas idéias, acompanha e melhora seus processos de negócio a fim de manter os parâmetros de qualidade e custos; e a atenção com o consumidor, fornecedores e outras empresas, estas formando parcerias que proporcionem novas fontes de idéias e oportunidades. Dessa forma, uma empresa como a Motorola mantem vantagem competitiva, inovando continuamente.

Da psicogênese a sociogênese: por uma interação radical no modelo dialético de Jean Piaget

A ideia central "desta tese é que a interação dialética entre o sujeito e o meio, que constitui a base do modelo teórico piagetiano deverá necessariamente ser uma interação radical. Partindo de uma observação do próprio Piaget de que na psicologia e epistemologia genéticas a relação de conhecimento havia sido estudada prioritariamente a partir do sujeito, deixando de ser explorada a partir do objeto, esta tese procura desenvolver as possibilidades abertas por esta exploração, quando se considera a expressão "meio" em sua concepção mais abrangente, incluindo não apenas objetos f1sicos, mas também e inclusive objetos sociais Discutindo a crítica sociológica feita ao modelo piagetiano que o critica por ter omitido a dimensão social em sua formulação, esta tese defenderá a hipótese de que não teria havido omissão: a dimensão social estaria embutida no próprio conceito de interação. Com base em argumentos antropológicos sobre a descontinuidade do espaço são efetuadas séries de generalizações que afinal, sugerem um enriquecimento da teoria piagetiana entendida a partir do objeto. As proposições desse novo modelo fornecem a base para sua aplicação no encaminhamento de problemas cognitivos sociais e psicossociais: é feita uma discussão critica aprofundada do debate sobre a inteligência da criança brasileira marginaliza da travado entre as equipes da Universidade de são Paulo e da Universidade Federal de Pernambuco; a análise -deste debate permite, por sua vez, trazer a construção cognitiva para um referencial antropológico e político. A tese se encerra indicando a correlação da psicogênese e sociogênese compreendidas a partir do modelo construído com a psicologia comunitária e a análise institucional.

O behaviorismo radical de B. F. Skinner e sua aplicabilidade socialmente relevante

o presente trabalho tem como objetivo a avaliação da capacidade do behaviorismo radical skinneriano'para fundamentar aplicações práticas dotadas de efetiva relevância humana e social, assim definidas em' função do caráter politicamente progressista e democratizante que se lhes possa imprimir. Essa avaliação é desenvolvida através de dois distintos, mas interrelacionados, procedimentos acadêmicos: uma argumentação discursiva baseada em pesquisa bibliográfica pertinente, que se complementapor um estudo empírico de campo a nível exploratório. A apreciação discursiva do behaviorismo radical é inicialmente conduzida sob uma perspectiva histórico-acadêmica, cujo foco contínuo de referência é o próprio agente individual basicamente responsável pelo gradativo processo de constituição desse sistema científico - B. F. Skinner. Em uma da etapa, o behaviorismo radical vem a ser discutido deforma mais impessoalizada, contra os sucessivos panos de fundo da filosofia da ciência, das relações sociais humanas e da ética implicada nas intervenções práticas sobre tais relações. O estudo exploratório, que então-se segue, consiste no julgamento da utilidade potencial de um instrumento de educação política popular, elaborado previamente a partir dos princípios behavioristas radicais básicos e seus desdobramentos psicossociológicos, e destinado a uma clientela sócio-economicamente desprivi1egiada, constituída de indivíduos adultos, de ambos os sexos, com escolaridade 'em torno do 19 grau completo. A avaliação dessa Cartilha de Contracontole Social através de entrevistas semi-estruturadas e um breve questionário objetivo, por quatorze lnformantes - qualificados em termos de sua 1iderança e/ou militância em associações de moradores de bairros e de favelas, sindicatos de trabalhadores, núcleos comunitários re1igiosos, entidades assistenciais autônomas e associações de servidores em organizações de trabalho - vem a apresentar, em linhas gerais, resultados muito positivos. A iniciativa é considerada extremamente séria e responsável; e o conteúdo da Carti1ha, bastante compatível com os objetivos desses movimentos populares, assim como muito útil para dotar as suas atividades de uma maior eficácia social. Evidencia-se, não obstante, uma restrição generalizada quanto à possibilidade de compreensão do texto por parte da população-alvo; o que deve, portanto, ensejar sua reformu1ação para o emprego em futuros projetos de prosseguimento dessa linha de pesquisa. Conclui-se, enfim, que a tese em seu todo parece apta a contribuir, se suficientemente divulgada, para a promoção de um maior interesse pelo behaviorismo de Skinner no âmbito acadêmico do Rio de Janeiro, bem como para a produção de um exercício mais eficaz de contracontro1e sobre as atuais práticas aversivas e/ou exploratórias de controle social.

New bacterial cellulose nanocomposites prepared by in situ radical polymerization of methacrylate monomers

Bacterial cellulose/polymethacrylate nanocomposites have received attention in numerous areas of study and in a variety of applications. The attractive properties of methacrylate polymers and bacterial cellulose, BC, allow the synthesis of new nanocomposites with distinct characteristics. In this study, BC/poly(glycidylmethacrylate) (BC/PGMA) and BC/poly(ethyleneglycol)methacrylate (BC/PPEGMA) nanocomposites were prepared through in situ free radical polymerization of GMA and PEGMA, respectively. Ammonium persulphate (APS) was used as an initiator and N,N’methylenebisacrilamide (MBA) was used as a crosslinker in BC/PGMA. Chemical composition, morphology, thermal stability, water absorption, mechanic and surface properties were determined through specific characterization techniques. The optimal polymerization was obtained at (1:2) for BC/PGMA, (1:2:0.2) ratio for BC/GMA/MBA and (1:20) for BC/PPEGMA, with 0.5% of initiator at 60 ºC during 6 h. A maximum of 67% and 87% of incorporation percentage was obtained, respectively, for the nanocomposites BC/PGMA/MBA and BC/PPEGMA. BC/PGMA nanocomposites exhibited an increase of roughness and compactation of the three-dimensional structure, an improvement in the thermal and mechanical properties, and a decrease in their swelling ability and crystallinity. On the other hand, BC/PPEGMA showed a decrease of stiffness of three-dimensional structure, improvement in thermal and mechanical properties, an increase in their swelling ability and a decrease the crystallinity. Both BC/polymethacrylate nanocomposites exhibited a basic surface character. The acid treatment showed to be a suitable strategy to modifiy BC/PGMA nanocomposites through epoxide ring-opening reaction mechanism. Nanocomposites became more compact, smooth and with more water retention ability. A decrease in the thermal and mechanical proprieties was observed. The new nanocomposites acquired properties useful to biomedical applications or/and removal of heavy metals due to the presence of functional groups.

Caracterização parcial e atividades farmacológicas do extrato rico em polissacarídeos sulfatatos da angiosperma marinha Halodule wrightii

Sulfated polysaccharides (PS) are biomolecules with a great biotechnological potential. There are few data about PS from high plants. In addition, pharmacological activities of PS from plants have not been carrying out. The aim of this work was extract PS from the angiosperm Halodule wrightii and study their anticoagulant and antioxidant activities. Histological analysis showed the presence of the PS manly in the roots. A polysaccharide-rich extract was obtained from H. wrightii by proteolysis followed by methanol and TCA precipitation. Chemical, infra-red analysis and agarose gel electrophoresis in 1.3 diaminopropane acetate buffer confirmed the presence of sulfated polysaccharides made by glucose, galactose, xylose and sulfate residues in the proportion 1: 0,9: 1: 1. In addition polyacrilamide electrophoresis have shown that extract is mainly compose by 11kDa sulfated polysaccharides. Pharmacological analysis have shown total antioxidant capacity (CAT) that resulted in 15,21 μg for equivalent of ascorbic acid, scavenging activity of the DPPH radical with 41,36 % of scavenging, activity of reducing power with the maximum of 0,290 nm (50 % of vitamin C activity) and scavenging activity superoxide radical (O2-) with a maximum of 32,23 %. Chelating activity of metal less than 4% and scavenging activity of the radical hydroxyl (OH-) less than 2%. Time of activated partial tromboplastin (aPTT) doubling the time of coagulation from 20μg of and protrombin time (PT) was not present. The data indicate that PS from Halodule wrightii could be considered for future applications in medicine, food production or cosmetic industry

Caracterização parcial e atividades farmacológicas do extrato rico em polissacarídeos sulfatados da angiosperma marinha Halodule wrightii

Sulfated polysaccharides (PS) are biomolecules with a great biotechnological potential. There are few data about PS from high plants. In addition, pharmacological activities of PS from plants have not been carrying out. The aim of this work was extract PS from the angiosperm Halodule wrightii and study their anticoagulant and antioxidant activities. Histological analysis showed the presence of the PS manly in the roots. A polysaccharide-rich extract was obtained from H. wrightii by proteolysis followed by methanol and TCA precipitation. Chemical, infra-red analysis and agarose gel electrophoresis in 1.3 diaminopropane acetate buffer confirmed the presence of sulfated polysaccharides made by glucose, galactose, xylose and sulfate residues in the proportion 1: 0,9: 1: 1. In addition polyacrilamide electrophoresis have shown that extract is mainly compose by 11kDa sulfated polysaccharides. Pharmacological analysis have shown total antioxidant capacity (CAT) that resulted in 15,21 μg for equivalent of ascorbic acid, scavenging activity of the DPPH radical with 41,36 % of scavenging, activity of reducing power with the maximum of 0,290 nm (50 % of vitamin C activity) and scavenging activity superoxide radical (O2-) with a maximum of 32,23 %. Chelating activity of metal less than 4% and scavenging activity of the radical hydroxyl (OH-) less than 2%. Time of activated partial tromboplastin (aPTT) doubling the time of coagulation from 20μg of and protrombin time (PT) was not present. The data indicate that PS from Halodule wrightii could be considered for future applications in medicine, food production or cosmetic industry

Caracterização dos marcadores químicos e avaliação de atividades biológicas do extrato de Spondias mombim

Spondias mombin is a fruitful species dispersed in tropical regions of America, Africa and Asia. In Brazil, the species can be found mainly in the northern and northeastern regions. Scarce chemical and pharmacological studies have been reported for S. mombin and until this moment studies about chemical markers were not developed. In this context, the aims of this study were to characterize the chemical markers from S. mombin leaves and evaluate their anti-inflammatory, antioxidant and antiproliferative potentials. The chemical profile of the hydroethanolic extract from S. mombin leaves analyzed by HPLC-DAD, through a validated method, allowed the identification and quantification of ellagic acid and chlorogenic acid. This extract showed anti-inflammatory potential in acute peritonitis model induced by carrageenan. The hydroethanolic extract from S. mombin leaves was subjected to a liquid-liquid partition with the solvents: n-hexane, dichloromethane, ethyl acetate and n-butanol. Regarding the anti-inflammatory potential of the fractions obtained they were active; however, ethyl acetate fraction at 200 mg/kg showed highlighted results. The compounds ellagic acid and chlorogenic acid also inhibited the leukocyte migration to the site of inflammation at 2.5, 5 and 10 mg/kg. The hydroethanolic extract, fractions and the chemical markers showed significant antioxidant potential when evaluated in different assays: DPPH Free-Radical Scavenging, Superoxide Radical Scavenging, Hydroxyl Radicals Scavenging and Reducing Power. Taken together our results showed that hydroethanolic extract of S. mombin leaves has ellagic acid and chlorogenic acid as bioactive markers and it demonstrated antiinflammatory and antioxidant properties besides no cytotoxicity against 3T3 cells. It enables us to suggest S. mombin as an important species to develop herbal drugs

As razões da esquerda radical PCB, PSTU e PSOL: estrutura organizativa e objetivos políticos

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

Imaginário radical e educação física: trajetória esportiva de corredores de longa distância

Cette étude propose une lecture du sport d endurance, prenant comme perspective théorique l imaginaire radical et considérant les dimensions socio-historiques e subjectives de la pratique de courses de longue distance. D abord, l échantillon la recherche a été composé de huit sujets-atlètes du groupe de courreurs de rue Sport Vida. Ainsi, em même temps que nous faisons une analyse socio-historique de cette pratique sportive, nous considérons l ensemble des aspects sócio-culturels et poursuivons la recherche avec comme objectif de comprendre les sens qui lui sont attribués par les sjuets-atlètes, au-delá de l aspect économique et de la consommation. Nous observons que, même si l altétismo qui est pratiqué a des aspects competitifs (economiques), les atlètes créent d autres sens pour continuer a pratiquer ce sport, comme les amitiés, être ensemble avec les amis. Ils rompent avec la logique déterministe du sport dépasser la limite du corps, vaincre à n importe quel prix, dépasser les collègues -, en cherchant des moments de solidarité, un sport sans violence et affectif. Nous percevons néanmoins des contradictions dans le discours de quelques atlètes quand confessent que le plus important est l amour du sport, les amitiés, mais réclament du manque de sponsorts et d appui pour pouvoir s entrainer tranquillement. Cette recherche a aussi montré que dans la pratique de ce sport, les atlètes construisent une obstination, sachant le sacrifice qu il impose au corps, mais cela se transforme en plaisir, excitation et recherche d émotions fortes. Valeurs éthiques sont aussi construites et valorisées dans l atlétisme, ce qui est observé lorsque que les sujets-atlètes critiquent avec véemence a propos de l usage de substances chimiques par les sportifs. En choisissant l imaginaire radical comme principale inspiration théorique pour cette recherche, il devient évident que le sport peut être ressignifié, à partir du moment que cet imaginaire est potencialisé dans l enseignement de l éducation physique, porvocant chez les élèves une réflexion critique sur la société et sur le sport, qui passe à être redimensionné vers la solidarité, avec démocratie et autonomie. Enfin, l étude a révélé que le sport d endurance est capable de créer des liens sociaux et structurer des relations à partir de cette pratique

Degradação foto-fenton de carbono orgânico total em efluentes da indústria de beneficiamento de castanha de caju

At the cashew nut processing industry it is often the generation of wastewaters containing high content of toxic organic compounds. The presence of these compounds is due mainly to the so called liquid of the cashew nut (CNSL). CNSL, as it is commercially known in Brazil, is the liquid of the cashew nut. It looks like an oil with dark brown color, viscous and presents a high toxicity index due to the chemical composition, i.e. phenol compounds, such as anacardic acid, cardol, 2-methyl cardol and monophenol (cardanol). These compounds are bio resistant to the conventional treatments. Furthermore, the corresponding wastewaters present high content of TOC (total organic carbon). Therefore due to the high degree of toxicity it is very important to study and develop treatments of these wastewaters before discharge to the environmental. This research aims to decompose these compounds using advanced oxidative processes (AOP) based on the photo-Fenton system. The advantage of this system is the fast and non-selective oxidation promoted by the hydroxyl radicals (●OH), that is under determined conditions can totally convert the organic pollutants to CO2 and H2O. In order to evaluate the decomposition of the organic charge system samples of the real wastewater od a processing cashew nut industry were taken. This industry was located at the country of the state of Rio Grande do Norte. The experiments were carried out with a photochemical annular reactor equipped with UV (ultra violet) lamp. Based on preliminary experiments, a Doehlert experimental design was defined to optimize the concentrations of H2O2 and Fe(II) with a total of 13 runs. The experimental conditions were set to pH equal to 3 and temperature of 30°C. The power of the lamps applied was 80W, 125W and 250W. To evaluate the decomposition rate measures of the TOC were accomplished during 4 hours of experiment. According to the results, the organic removal obtained in terms of TOC was 80% minimum and 95% maximum. Furthermore, it was gotten a minimum time of 49 minutes for the removal of 30% of the initial TOC. Based on the obtained experimental results, the photo-Fenton system presents a very satisfactory performance as a complementary treatment of the wastewater studied

Radical scavenging activity of orange and tangerine varieties cultivated in Brazil

Four citrus fruit varieties cultivated in Brazil (two kinds of sweet orange and two kinds of tangerine) were analyzed for physicochemical characteristics contents of total phenolics, total carotenoids and ascorbic acid, and antioxidant activities. The antioxidant activities of aqueous, methanolic, and acetone extracts of the citrus fruit juices were assessed on the basis of their ability to scavenge 1,1-diphenyl-2-picrylhydrazyl (DPPH(center dot)). The cravo tangerine has the highest content of citric acid, while the pera orange is richest in ascorbic acid. The lima orange has the highest total phenolic contents, and the ponkan the highest total carotenoids. The antioxidant activities, expressed as the concentration of antioxidant able to scavenge 50% of the initial DPPH(center dot) (EC(50)), ranged from 139.1+/-27.3 to 182.2+/-28.8 g extract/l for juice of orange varieties and 186.3+/-29.6 to 275.5+/-3.3g extract/l for juice of tangerine citrus varieties. In methanolic extracts the EC(50) ranged from 192.5+/-43.1 to 267.4+/-41.4 g extract/l for orange varieties and from 225.2+/-69.8 to 336.3+/-27.2 g extract/l for tangerine varieties. For EC(50) values of acetone fractions, there were no statistically significant differences between the different varieties. For every citrus fruit in the present study, the radical scavenging capacity was higher in the aqueous than in the methanolic or acetone fractions.

Free radical scavenging profile and myeloperoxidase inhibition of extracts from antidiabetic plants: Bauhinia forficata and Cissus sicyoides

There is abundant evidence that reactive oxygen species are implicated in several physiological and pathological processes. To protect biological targets from oxidative damage. antioxidants must react with radicals and other reactive species faster than biological substrates do. The aim of the present study was to determine the in vitro antioxidant activity of aqueous extracts from leaves of Bauhinia forficata Link (Fabaceae - Caesalpinioideae) and Cissus sicyoides L. (Vitaceae) (two medicinal plants used popularly in the control of diabetes mellitus), using several different assay systems, namely, 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) decolorization. superoxide anion radical (O-2 center dot-) scavenging and myeloperoxidase (MPO) activity. In the ABTS assay for total antioxidant activity, B. forficata showed IC50 8.00 +/- 0.07 mu g/mL, while C. sicyoides showed IC50 13.0 +/- 0.2 mu g/mL. However, the extract of C. sicyoides had a stronger effect on O-2 center dot- (IC50 60.0 +/- 2.3 mu p/mL) than the extract of B. forficata (IC50 90.0 +/- 4.4 mu g/mL). B. forficata also had a stronger inhibitory effect on MPO activity, as measured by guaiacol oxidation, than C. sicyoides. These results indicate that aqueous extracts of leaves of B. forficata and C. sicyoides are a potential source of natural antioxidants and may be helpful in the prevention of diabetic complications associated with oxidative stress.

The effect of pH on horseradish peroxidase-catalyzed oxidation of melatonin: production of N-1-acetyl-N-2-formyl-5-methoxykynuramine versus radical-mediated degradation

There is a g-rowing body of evidence that melatonin and its oxidation product, N-1-acetyl-N-2-formyl-5-methoxykynuramine (AFMK), have anti-inflammatory properties. From a nutritional point of view, the discovery of melatonin in plant tissues emphasizes the importance of its relationship with plant peroxidases. Here we found that the pH of the reaction mixture has a profound influence in the reaction rate and products distribution when melatonin is oxidized by the plant enzyme horseradish peroxidase. At pH 5.5. 1 mm of melatonin was almost completely oxidized within 2 min, whereas only about 3% was consumed at pH 7.4. However, the relative yield of AFMK was higher in physiological pH. Radical-mediated oxidation products, including 2-hydroxymelatonin a dimer of, 2-hydroxymelatonin and O-demethylated dimer of melatonin account for the fast consumption of melatonin at pH 5.5. The higher production of AFMK at pH 7.4 was explained by the involvement of compound III of peroxidases as evidenced by spectral studies. on the other hand, the fast oxidative degradation at pH 5.5 was explained by the classic peroxidase cycle.