6,751 research outputs found

    Avaliação de antibiose e não-preferência em cultivares de milho selecionados com resistência a lagarta-do-cartucho.

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    Dentre os fatores que contribuem para reduzir a produtividade das lavouras de milho estao as pragas, destacando-se a lagarta-do-cartucho, Spodoptera frugiperda, a qual pode reduzir a producao em ate 34%. Um dos metodos de controle de pragas, cujo custo e reduzido e nao causa efeitos indesejaveis ao ambiente, e o desenvolvimento de cultivares resistentes. Diversas fontes de resistencia foram identificadas, linhagens desenvolvidas, registradas e liberadas ao publico; entretanto, pouca informacao tem sido veiculada a respeito dos mecanismos e causas dessa resistencia. O objetivo do presente trabalho foi estudar os mecanismos de resistencia, nao-preferencia e antibiose em genotipos de milho selecionados, com resistencia a S. frugiperda. Os ensaios foram conduzidos em laboratorio e em casa de vegetacao da EMBRAPA/CNPMS. O genotipo CMS 14C apresentou antibiose influindo negativamente na biologia de S. frugiperda. 'CMS 24' e 'CMS 23' apresentaram tambem esses mecanismo, porem em menor intensidade. Foi constatada nao-preferencia alimentar das lagartas para 'Zapalote Chico' e 'BR 201'. Nao-preferencia para oviposicao foi constatada em 'CMS 14C' e 'Zapalote Chico'

    Design of Wireless Sensor Nodes for Structural Health Monitoring applications

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    Enabling low-cost distributed monitoring, wireless sensor networks represents an interesting solution for the implementation of structural health monitoring systems. This work deals with the design of wireless sensor networks for health monitoring of civil structures, specifically focusing on node design in relation to the requirements of different structural monitoring application classes. Design problems are analysed with specific reference to a large-scale experimental setup (the long-term structural monitoring of the Basilica S. Maria di Collemaggio, L’Aquila, Italy). Main limitations emerged are highlighted, and adopted solution strategies are outlined, both in the case of commercial sensing platform and of full custom solutions

    Role of Notch2 pathway in mature B cell malignancies

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    In recent decades, the Notch pathway has been characterized as a key regulatory signaling of cell-fate decisions evolutionarily conserved in many organisms and different tissues during lifespan. At the same time, many studies suggest a link between alterations of this signaling and tumor genesis or progression. In lymphopoiesis, the Notch pathway plays a fundamental role in the correct differentiation of T and B cells, but its deregulated activity leads to leukemic onset and evolution. Notch and its ligands Delta/Jagged exhibit a pivotal role in the crosstalk between leukemic cells and their environment. This review is focused in particular on Notch2 receptor activity. Members of Notch2 pathway have been reported to be mutated in Chronic Lymphocytic Leukemia (CLL), Splenic Marginal Zone Lymphoma (SMZL) and Nodal Marginal Zone Lymphoma (NMZL). CLL is a B cell malignancy in which leukemic clones establish supportive crosstalk with non-malignant cells of the tumor microenvironment to grow, survive, and resist even the new generation of drugs. SMZL and NMZL are indolent B cell neoplasms distinguished by a distinct pattern of dissemination. In SMZL leukemic cells affect mainly the spleen, bone marrow, and peripheral blood, while NMZL has a leading nodal distribution. Since Notch2 is involved in the commitment of leukemic cells to the marginal zone as a major regulator of B cell physiological differentiation, it is predominantly affected by the molecular lesions found in both SMZL and NMZL. In light of these findings, a better understanding of the Notch receptor family pathogenic role, in particular Notch2, is desirable because it is still incomplete, not only in the physiological development of B lymphocytes but also in leukemia progression and resistance. Several therapeutic strategies capable of interfering with Notch signaling, such as monoclonal antibodies, enzyme or complex inhibitors, are being analyzed. To avoid the unwanted multiple “on target” toxicity encountered during the systemic inhibition of Notch signaling, the study of an appropriate pharmaceutical formulation is a pressing need. This is why, to date, there are still no Notch-targeted therapies approved. An accurate analysis of the Notch pathway could be useful to drive the discovery of new therapeutic targets and the development of more effective therapies

    Insulin-stimulated phosphorylation of endothelial nitric oxide synthase at serine-615 contributes to nitric oxide synthesis

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    Insulin stimulates endothelial NO (nitric oxide) synthesis via PKB (protein kinase B)/Akt-mediated phosphorylation and activation of eNOS (endothelial NO synthase) at Ser-1177. In previous studies, we have demonstrated that stimulation of eNOS phosphorylation at Ser-1177 may be required, yet is not sufficient for insulin-stimulated NO synthesis. We therefore investigated the role of phosphorylation of eNOS at alternative sites to Ser-1177 as candidate parallel mechanisms contributing to insulin-stimulated NO synthesis. Stimulation of human aortic endothelial cells with insulin rapidly stimulated phosphorylation of both Ser-615 and Ser-1177 on eNOS, whereas phosphorylation of Ser-114, Thr-495 and Ser-633 was unaffected. Insulin-stimulated Ser-615 phosphorylation was abrogated by incubation with the PI3K (phosphoinositide 3-kinase) inhibitor wortmannin, infection with adenoviruses expressing a dominant-negative mutant PKB/Akt or pre-incubation with TNFα (tumour necrosis factor α), but was unaffected by high culture glucose concentrations. Mutation of Ser-615 to alanine reduced insulin-stimulated NO synthesis, whereas mutation of Ser-615 to aspartic acid increased NO production by NOS in which Ser-1177 had been mutated to an aspartic acid residue. We propose that the rapid PKB-mediated stimulation of phosphorylation of Ser-615 contributes to insulin-stimulated NO synthesis

    Fracture energy of sustainable geopolymer composites with and without the addition of slaughterhouse by-products as fibre-reinforcement: An experimental investigation

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    This work focuses on the development and on the mechanical characterization of geopolymer composites to be used as sustainable plasters or mortars. The starting point of the work is the synthesis of a geopolymer binder, which is subsequently used for the production of two different mortars: the first one is obtained by simply adding fine aggregates (control mortar), while in the second case, also slaughterhouse wastes (SHW) are included in the admixture. Nowadays, slaughtering industry produces a large amount of biological wastes, that are usually discarded via incineration or landfills. Among SHW, horns and hooves, which are rich in keratin, can be potentially used as additives in the manufacturing process of mortars, both in the form of fibre-reinforcement, as well as fine aggregates and fillers. In the second mortar considered in this work, 2% of SHW fibres and 2% of SHW filler are added in the admixture. The mechanical properties of the three products are experimentally investigated and compared to each other. Apart for compressive strength, close attention is paid to the flexural behaviour and to the determination of fracture energy. To evaluate the effect of SHW addition on crack propagation and width, digital image correlation technique is also adopted
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