368 research outputs found

    Espectrometria de infravermelho próximo na predição da textura de solos desenvolvidos de basalto.

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    A textura dos solos tem sido determinada através de métodos analíticos que muitas vezes são caros e lentos. Ademais, em solos muito argilosos, a dispersão química e mecânica nem sempre é eficiente em separar a fração silte da fração argila, superestimando o conteúdo de silte dos solos. O objetivo do trabalho foi testar a espectroscopia de reflectância de infravermelho próximo (NIRS) na avaliação da textura de solos de basalto. Foram coletadas 214 amostras de terra na região Norte do Estado do Paraná, Brasil, nos municípios de Bela Vista do Paraíso e Londrina, em áreas com predominância de Latossolos, Nitossolos e Neossolos, classificados. As amostras foram coletadas nas profundidades de 0-20 cm e 60-80 cm. Foi realizada análise textural pela dispersão química e mecânica e em seguida as amostras foram escaneadas em um espectrômetro modelo FOSS NIRS SYSTENS XDS, na banda de reflectância entre 400 e 2500 nm. Os dados espectrais foram analisados e comparados aos resultados obtidos com o método da pipeta, através do software WinISI III v. 1.61e. Foi possível verificar que na camada 60-80 cm os teores de argila foram superiores aos da camada 0-20 cm, em função de pequenas translocações de argila verificadas nesses solos. Em relação à predição da textura pelo NIRS, não foi possível obter boa acurácia para nenhuma das frações granulométricas analisadas, uma vez que os coeficientes de correlação da calibração foram apenas 0,55; 0,55 e 0,53 para argila, silte e areia, respectivamente. Nesta situação o indicado seria testar novos métodos de análise de referência e novos tratamentos estatísticos para se ter um melhor indicativo do potencial de uso da técnica

    Root production and quality attributes of sweet potato genotypes in Brasília - DF, Brazil, during two cropping seasons.

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    Avaliou-se nove genótipos de batata-doce: BRS Amélia, Beauregard, Brazlândia Branca, Brazlândia Rosada, Brazlândia Roxa, BRS Cuia, Princesa, BRS Rubissol e um genótipo local em delineamento de blocos casualizados, com quatro repetições. Estimou-se características relacionadas a produção de raízes, características de qualidade e danos causador por insetos

    Effect of a wild blueberry (Vaccinium angustifolium) drink intervention on markers of oxidative stress, inflammation and endothelial function in humans with cardiovascular risk factors

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    Purpose Wild blueberries (WB) (Vaccinium angustifolium) are rich sources of polyphenols, such as flavonols, phenolic acids and anthocyanins (ACNs), reported to decrease the risk of cardiovascular and degenerative diseases. This study investigated the effect of regular consumption of a WB or a placebo (PL) drink on markers of oxidative stress, inflammation and endothelial function in subjects with risk factors for cardiovascular disease. Methods Eighteen male volunteers (ages 47.8 ? 9.7 years; body mass index 24.8 ? 2.6 kg/m2) received according to a cross-over design, a WB (25 g freeze-dried powder, providing 375 mg of ACNs) or a PL drink for 6 weeks, spaced by a 6-week wash-out. Endogenous and oxidatively induced DNA damage in blood mononuclear cells, serum interleukin levels, reactive hyperemia index, nitric oxide, soluble vascular adhesion molecule concentration and other variables were analyzed. In conclusion, the consumption of the WB drink for 6 weeks significantly reduced the levels of oxidized DNA bases and increased the resistance to oxidatively induced DNA damage. Future studies should address in greater detail the role of WB in endothelial functio

    "Nutrizione e Rischio Cardiovascolare"

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    Wild blueberries are rich sources of polyphenols such as anthocyanins capable of counteracting oxidative stress, influencing vasomotor tone and modulating gene expression associated with disease processes such as cardiovascular disease

    Anaplasma marginale infection in cattle from southwestern Amazonia.

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    study provides the first epidemiological data regarding infection by Anaplasma marginale in cattle reared in south-western Brazilian Amazonia. One simple procedure was adapted for the extraction of DNA from blood clots collected in seven microregions of Rondônia State and two mesoregions of Acre State. PCR method was used to asses the frequency of A. marginale infections in 4 to12-month-old cattle. The cattle infection was investigated by polymerase chain reaction (PCR) using the specific primer ?msp5? for A. marginale. The DNA amplifications revealed that the mean frequency of A. marginale infection was 98.6% (1,627/1,650) in samples from Rondonia, and 92.87% (208/225) in samples from Acre. The high frequency of A. marginale infections in 4 to 12- month-old cattle indicate a situation of enzootic stability in the studied areas and are comparable to those detected by immunodiagnosis in different endemic regions in Brazil. The DNA extraction of clotted blood method described here can be used for epidemiological studies on anaplasmosis and other bovine hemoparasites

    Subsídios para o programa de melhoramento genético de batata-doce in natura.

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    O objetivo do trabalho foi coletar informações para validar e subsidiar as tomadas de decisão relacionadas com os rumos do programa de melhoramento genético de batata-doce.Editores: Adalton Mazetti Fernandes, Unesp; André Ricardo Zeist, UFSC

    Human natural killer cells mediate adaptive immunity to viral antigens

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    Adaptive immune responses are defined as antigen sensitization–dependent and antigen-specific responses leading to establishment of long-lived immunological memory. Although natural killer (NK) cells have traditionally been considered cells of the innate immune system, mounting evidence in mice and nonhuman primates warrants reconsideration of the existing paradigm that B and T cells are the sole mediators of adaptive immunity. However, it is currently unknown whether human NK cells can exhibit adaptive immune responses. We therefore tested whether human NK cells mediate adaptive immunity to virally encoded antigens using humanized mice and human volunteers. We found that human NK cells displayed vaccination-dependent, antigen-specific recall responses in vitro, when isolated from livers of humanized mice previously vaccinated with HIV-encoded envelope protein. Furthermore, we discovered that large numbers of cytotoxic NK cells with a tissue-resident phenotype were recruited to sites of varicella-zoster virus (VZV) skin test antigen challenge in VZV-experienced human volunteers. These NK-mediated recall responses in humans occurred decades after initial VZV exposure, demonstrating that NK memory in humans is long-lived. Our data demonstrate that human NK cells exhibit adaptive immune responses upon vaccination or infection. The existence of human memory NK cells may allow for the development of vaccination-based approaches capable of establishing potent NK-mediated memory functions contributing to host protection
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