133 research outputs found

    Monocrystalline silicon carbide nanoelectromechanical systems

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    SiC is an extremely promising material for nanoelectromechanical systems given its large Young's modulus and robust surface properties. We have patterned nanometer scale electromechanical resonators from single-crystal 3C-SiC layers grown epitaxially upon Si substrates. A surface nanomachining process is described that involves electron beam lithography followed by dry anisotropic and selective electron cyclotron resonance plasma etching steps. Measurements on a representative family of the resulting devices demonstrate that, for a given geometry, nanometer-scale SiC resonators are capable of yielding substantially higher frequencies than GaAs and Si resonators

    O contributo do projecto INTERFRUTA II para o desenvolvimento da fruticultura na ilha Terceira, Açores

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    13º Congresso da APDR (Associação Portuguesa para o Desenvolvimento Rural). Angra do Heroísmo, Julho de 2007.O Projecto Interfruta II é um projecto apoiado pelo programa Interreg III-B, desenvolvido nas Ilhas da Madeira, Tenerife (Canárias) e Terceira (Açores) destinado a contribuir para a promoção da fruticultura e viticultura nestas três regiões insulares, procurando uma melhoria dos conhecimentos sobre os problemas fitossanitários que afectam as macieiras, bananeiras, castanheiros e a vinha, aplicando técnicas que contribuam decisivamente para o conhecimento e procura de soluções, numa vertente de prospecção das pragas-chave, fauna auxiliar, doenças e vírus que afectam essas culturas. Destaca-se o facto de inicialmente se ter procedido à realização de 160 inquéritos aos produtores e ao levantamento e identificação, através de SIG, das áreas de produção frutícola da Ilha. Para a análise dos factores climáticos ao nível da parcela, foram instaladas nas três zonas em estudo, estações meteorológicas de leitura automática.ABSTRACT: The INTERFRUTA project is financed by the European Commission Interreg III-B Programme and was developed for the islands of Madeira, Tenerife and Terceira for the improvement of fruit and vineyard production in these three Atlantic regions. The project goal is a better knowledge of the phytossanitary problems that affect apples, bananas, chestnut and vineyards, applying methods that will contribute to solutions based on the survey of key pests, diseases and beneficial organisms. All these work began with a survey to 160 producers and those data permitted, applying GIS techniques to them to identify the Terceira island fruit and vineyard production areas. To register the climate conditions in each area studied fully automatic meteorological stations were put in each of the three studied areas

    O projecto INTERFRUTA II e o seu papel no desenvolvimento da fruticultura na ilha Terceira

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    I Congresso de Fruticultura e Viticultura. Angra do Heroísmo 17-19 Abril 2008.Trabalho de investigação desenvolvido no projecto INTERFRUTA II, financiado pelo programa INTERREG III-B (05/MAC/3.1/A4).O Projecto INTERFRUTA II é um projecto desenvolvido nas Ilhas da Madeira, Tenerife (Canárias) e Terceira (Açores) destinado a contribuir para a promoção da fruticultura e viticultura nestas três regiões insulares, procurando uma melhoria dos conhecimentos sobre as culturas de macieiras, bananeiras, castanheiros e vinha. Englobando um estudo integrado que envolve a climatologia, fenologia, pedologia, problemas fitossanitários, pragas-chave e a fauna auxiliar presente nas parcelas estudadas, distribuídas pela zona Norte e Sul da Ilha, aplicando técnicas que contribuam decisivamente para o conhecimento e procura de soluções inovadoras que conduzam ao acréscimo do rendimento dos produtores e a uma menor utilização e aplicação de pesticidas. Para atingir estes objectivos numa fase inicial realizaram-se 160 inquéritos aos produtores e foi possível a identificação, através de SIG, das áreas de produção frutícola da Ilha. Para a análise dos factores climáticos ao nível da parcela, foram instaladas estações meteorológicas de leitura automática. Na parte relativa ao estudo da fenologia e produção para além da caracterização foi avaliado o impacto da polinização na taxa de vingamento dos frutos de macieira. Dentro dos problemas fitossanitários, na identificação das pragas-chave de cada cultura foi utilizada a observação visual de órgãos predefinidos e a monitorização através de armadilhas com feromona sexual e utilizadas placas cromotrópicas com cola. Nos fungos foi utilizada a observação visual e na prospecção de vírus e fitoplasmas utilizaram-se técnicas moleculares (ELISA) e PCR. Na prospecção da fauna auxiliar foi a técnica dos batimentos (ou pancadas) e a armadilha Malaise. Foi também realizado o levantamento das plantas auxiliares de produção e feita a sua identificação. Nas pragas-chave de cada uma das culturas, centrou-se a investigação sobre as mais importantes. A mosca-do-Mediterrâneo (C. capitata Wied.) foi uma delas, onde com o objectivo da sua monitorização, recorrendo aos SIG, foi montada uma rede de armadilhas em toda a ilha. Na bananeira, centrou-se todo o trabalho no gorgulho-da-bananeira (Cosmopolites sordidus Germar) e nas tripes. No castanheiro, no bichado-da-castanha (Cydia splendana Hubner) tendo sido avaliados os prejuízos que causa e conhecida a sua curva de voo através da sua monitorização usando armadilhas com feromona sexual. Na vinha, o míldio é a doença que mais contribuiu para a diminuição da produção de uva para vinho. Nas macieiras, os principais problemas decorrem da presença de aranhiço vermelho (Panonychus ulmi Koch), traça-oriental (Cydia molesta) e bichado (Cydia pomonella L.). Para a recolha e divulgação de toda a informação foi construída uma página Web do projecto, disponível na Internet (www.interfuta.angra.uac.pt) e uma base de dados fitossanitários de diagnóstico da Macaronésia (PROFITOMAC) para a identificação de todos os problemas que afectam estas culturas nos três arquipélagos em que o projecto de desenvolve. No âmbito das actividades do projecto foram ainda realizados alguns cursos de formação de curta duração para técnicos e produtores

    MYCN-driven fatty acid uptake is a metabolic vulnerability in neuroblastoma

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    Half of high-risk neuroblastoma patients have MYCN amplification. Here, the authors show that MYCN induces fatty acid uptake and synthesis to support neuroblastoma and inhibition of a fatty acid transporter impairs tumor progression in preclinical models.Neuroblastoma (NB) is a childhood cancer arising from sympatho-adrenal neural crest cells. MYCN amplification is found in half of high-risk NB patients; however, no available therapies directly target MYCN. Using multi-dimensional metabolic profiling in MYCN expression systems and primary patient tumors, we comprehensively characterized the metabolic landscape driven by MYCN in NB. MYCN amplification leads to glycerolipid accumulation by promoting fatty acid (FA) uptake and biosynthesis. We found that cells expressing amplified MYCN depend highly on FA uptake for survival. Mechanistically, MYCN directly upregulates FA transport protein 2 (FATP2), encoded by SLC27A2. Genetic depletion of SLC27A2 impairs NB survival, and pharmacological SLC27A2 inhibition selectively suppresses tumor growth, prolongs animal survival, and exerts synergistic anti-tumor effects when combined with conventional chemotherapies in multiple preclinical NB models. This study identifies FA uptake as a critical metabolic dependency for MYCN-amplified tumors. Inhibiting FA uptake is an effective approach for improving current treatment regimens

    Early glycoprotein IIb–IIIa inhibitors in primary angioplasty (EGYPT) cooperation: an individual patient data meta-analysis

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    Background: Even though time-to-treatment has been shown to be a determinant of mortality in primary angioplasty, the potential benefits from early pharmacological reperfusion by glycoprotein (Gp) IIb-IIIa inhibitors are still unclear. The aim of this meta-analysis was to combine individual data from all randomised trials conducted on facilitated primary angioplasty by the use of early Gp IIb-IIIa inhibitors. Methods and results: The literature was scanned by formal searches of electronic databases (MEDLINE, EMBASE) from January 1990 to October 2007. All randomised trials on facilitation by the early administration of Gp IIb-IIIa inhibitors in ST-segment elevation myocardial infarction (STEMI) were examined. No language restrictions were enforced. Individual patient data were obtained from 11 out of 13 trials, including 1662 patients (840 patients (50.5%) randomly assigned to early and 822 patients (49.5%) to late Gp IIb-IIIa inhibitor administration). Preprocedural Thrombolysis in Myocardial Infarction Study (TIMI) grade 3 flow was more frequent with early Gp IIb-IIIa inhibitors. Postprocedural TIMI 3 flow and myocardial blush grade 3 were higher with early Gp IIb IIIa inhibitors but did not reach statistical significance except for abciximab, whereas the rate of complete ST-segment resolution was significantly higher with early Gp IIb-IIIa inhibitors. Mortality was not significantly different between groups, although early abciximab demonstrated improved survival compared with late administration, even after adjustment for clinical and angiographic confounding factors. Conclusions: This meta-analysis shows that pharmacological facilitation with the early administration of Gp IIb IIIa inhibitors in patients undergoing primary angioplasty for STEMI is associated with significant benefits in terms of preprocedural epicardial recanalisation and ST-segment resolution, which translated into non-significant mortality benefits except for abciximab

    Pan-Cancer Analysis of lncRNA Regulation Supports Their Targeting of Cancer Genes in Each Tumor Context

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    Long noncoding RNAs (lncRNAs) are commonly dys-regulated in tumors, but only a handful are known toplay pathophysiological roles in cancer. We inferredlncRNAs that dysregulate cancer pathways, onco-genes, and tumor suppressors (cancer genes) bymodeling their effects on the activity of transcriptionfactors, RNA-binding proteins, and microRNAs in5,185 TCGA tumors and 1,019 ENCODE assays.Our predictions included hundreds of candidateonco- and tumor-suppressor lncRNAs (cancerlncRNAs) whose somatic alterations account for thedysregulation of dozens of cancer genes and path-ways in each of 14 tumor contexts. To demonstrateproof of concept, we showed that perturbations tar-geting OIP5-AS1 (an inferred tumor suppressor) andTUG1 and WT1-AS (inferred onco-lncRNAs) dysre-gulated cancer genes and altered proliferation ofbreast and gynecologic cancer cells. Our analysis in-dicates that, although most lncRNAs are dysregu-lated in a tumor-specific manner, some, includingOIP5-AS1, TUG1, NEAT1, MEG3, and TSIX, synergis-tically dysregulate cancer pathways in multiple tumorcontexts

    Unexpected differential metabolic responses of Campylobacter jejuni to the abundant presence of glutamate and fucose

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    Introduction: Campylobacter jejuni is the leading cause of foodborne bacterial enteritis in humans, and yet little is known in regard to how genetic diversity and metabolic capabilities among isolates affect their metabolic phenotype and pathogenicity. Objectives: For instance, the C. jejuni 11168 strain can utilize both l-fucose and l-glutamate as a carbon source, which provides the strain with a competitive advantage in some environments and in this study we set out to assess the metabolic response of C. jejuni 11168 to the presence of l-fucose and l-glutamate in the growth medium. Methods: To achieve this, untargeted hydrophilic liquid chromatography coupled to mass spectrometry was used to obtain metabolite profiles of supernatant extracts obtained at three different time points up to 24 h. Results: This study identified both the depletion and the production and subsequent release of a multitude of expected and unexpected metabolites during the growth of C. jejuni 11168 under three different conditions. A large set of standards allowed identification of a number of metabolites. Further mass spectrometry fragmentation analysis allowed the additional annotation of substrate-specific metabolites. The results show that C. jejuni 11168 upon l-fucose addition indeed produces degradation products of the fucose pathway. Furthermore, methionine was faster depleted from the medium, consistent with previously-observed methionine auxotrophy. Conclusions: Moreover, a multitude of not previously annotated metabolites in C. jejuni were found to be increased specifically upon l-fucose addition. These metabolites may well play a role in the pathogenicity of this C. jejuni strain.</p
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