54 research outputs found

    Mapping of functionalized regions on carbon nanotubes by scanning tunneling microscopy

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    Scanning tunneling microscopy (STM) gives us the opportunity to map the surface of functionalized carbon nanotubes in an energy resolved manner and with atomic precision. But this potential is largely untapped, mainly due to sample stability issues which inhibit reliable measurements. Here we present a simple and straightforward solution that makes away with this difficulty, by incorporating the functionalized multiwalled carbon nanotubes (MWCNT) into a few layer graphene - nanotube composite. This enabled us to measure energy resolved tunneling conductance maps on the nanotubes, which shed light on the level of doping, charge transfer between tube and functional groups and the dependence of defect creation or functionalization on crystallographic orientation.Comment: Keywords: functionalization, carbon nanotubes, few layer graphene, STM, CITS, ST

    Oxidative Stress in Neurodegenerative Diseases

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    Representações sociais de conselheiros de saúde acerca do direito à saúde e da cidadania

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    RESUMO Objetivo Conhecer a estrutura das representações sociais de direito à saúde e cidadania de conselheiros municipais de saúde. Método Estudo qualitativo, fundamentado nas Teorias das Representações Sociais e do Núcleo Central, realizado em oito municípios da Região Integrada de Desenvolvimento do Entorno do Distrito Federal, Brasil. A amostra intencional foi composta por conselheiros municipais de saúde. Entre junho e dezembro de 2012 aplicaram-se questionários de evocação livre, dos quais foram respondidos 68 com o termo indutor Direito à Saúde e 64 com o termo indutor Cidadania. Os dados foram analisados por meio do software EVOC e da análise de conteúdo de Bardin. Resultados O campo representacional de direito à saúde está associado à ideia de direito universal garantido pela Constituição e pelo SUS e de cidadania vinculado aos direitos e deveres. Conclusões As concepções de direito à saúde são entendidas enquanto condição para alcance da cidadania e cidadania como proteção social

    Correlation between carotenoid concentrations in serum and normal breast adipose tissue of women with benign breast tumor or breast cancer

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    To evaluate the relationship between carotenoid concentrations in serum and breast tissue, we measured serum carotenoid concentrations and endogenous carotenoid levels in breast adipose tissue of women with benign breast tumor (n = 46) or breast cancer (n = 44). Before extraction, serum was digested with lipase and cholesterol esterase, and breast adipose tissue was saponified. Serum and tissue carotenoids were extracted with ether/hexane and measured by using HPLC with a C30 column. Serum retinoic acid was extracted with chloroform/methanol and measured using HPLC with a C18 column. There were no significant differences in serum carotenoids [lutein, zeaxanthin, cryptoxanthin (both α- and β-), α-carotene, all-trans β-carotene, 13-cis β-carotene and lycopene], retinoids (retinol, all-trans and 13-cis retinoic acids), and α- and -γ- tocopherol concentrations between benign breast tumor patients and breast cancer patients. A substantial amount of 9-cis β- carotene was present in adipose tissue and was the only carotenoid that had a significantly lower level in benign breast tumor patients than in breast cancer patients. Correlations between carotenoid concentrations in serum and in breast adipose tissue were determined by combining the data of the two groups. Concentrations of the major serum carotenoids except cryptoxanthin showed significant correlations with breast adipose tissue carotenoid levels. When the concentrations of serum carotenoids were adjusted for serum triglycerides or LDL, correlations between serum carotenoid concentrations and breast adipose tissue carotenoid levels markedly increased, including that of cryptoxanthin (P <0.001). The strong correlation between serum carotenoid concentrations and endogenous breast adipose tissue carotenoid levels indicate that dietary intake influences adipose tissue carotenoid levels as well as serum concentrations, and that adipose tissue is a dynamic reservoir of fat-soluble nutrients
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