1,629 research outputs found

    Efeito do número de nós sobre o crescimento inicial de plantas de crajiru (Arrabidaea chica (Humb. & Bonpl.) B. Verl.).

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    O objetivo deste trabalho foi avaliar tipos de estacas e o efeito do número de brotações sobre o crescimento e produção de folhas de crajiru.bitstream/CPAF-RO-2010/12384/1/ct-99-crajiru.pd

    Apresentação – Ensino de História: entre Bases Nacionais e a formação de professores

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    Apresentamos os onze artigos que compõem o dossiê Bases Nacionais e Ensino de História, e que contemplam algumas questões relativas a embates, a desafios e a possibilidades que tais documentos envolvem em relação à educação básica e à formação de professores. Os trabalhos foram organizados começando pelo Brasil, passando por uma abordagem comparada da realidade nacional com outros países e, finalmente, tratando de discussões e normativas de outros países, da América do Sul, América Central, América do Norte e Europa. Esperamos contribuir para a reflexão e melhor compreensão desse processo de disputas sobre a educação e, aqui, particularmente, sobre o ensino de História, que deve ser apreendido em perspectiva histórica, e que pode apresentar, como os artigos discutem, tanto similaridades entre diferentes países quanto especificidades, bem como muitos desafios e possibilidades

    A new pathway for Mannitol metabolism in yeasts suggests a link to the evolution of alcoholic fermentation

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    This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.The yeasts belonging to the Wickerhamiella and Starmerella genera (W/S clade) share a distinctive evolutionary history marked by loss and subsequent reinstatement of alcoholic fermentation mediated by horizontal gene transfer events. Species in this clade also share unusual features of metabolism, namely the preference for fructose over glucose as carbon source, a rare trait known as fructophily. Here we show that fructose may be the preferred sugar in W/S-clade species because, unlike glucose, it can be converted directly to mannitol in a reaction with impact on redox balance. According to our results, mannitol is excreted to the growth medium in appreciable amounts along with other fermentation products such as glycerol and ethanol but unlike the latter metabolites mannitol production increases with temperature. We used comparative genomics to find genes involved in mannitol metabolism and established the mannitol biosynthesis pathway in W/S-clade species Starmerella bombicola using molecular genetics tools. Surprisingly, mannitol production seems to be so important that St. bombicola (and other W/S-clade species) deploys a novel pathway to mediate the conversion of glucose to fructose, thereby allowing cells to produce mannitol even when glucose is the sole carbon source. Using targeted mutations and 13C-labeled glucose followed by NMR analysis of end-products, we showed that the novel mannitol biosynthesis pathway involves fructose-6-phosphate as an intermediate, implying a key role for a yet unknown fructose-6-P phosphatase. We hypothesize that mannitol production contributed to mitigate the negative effects on redox balance of the ancient loss of alcoholic fermentation in the W/S clade. Presently, mannitol also seems to play a role in stress protection.info:eu-repo/semantics/publishedVersio

    A strategy to increase and assess vaccine coverage in the north of Portugal

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    In the Northern Health Region of Portugal, vaccine coverage is measured by checking and studying individual vaccination records in health centres. Each year from 2001-2004, birth cohorts who were over 2, 6 and 14 years of age were selected for assessment. Data collection occurred on January the following year and meetings with district immunisation coordinators took place every March. For all vaccines and birth cohorts considered, vaccine coverage values observed in the north of Portugal were excellent. In this paper, we make comparisons with published international data on vaccine coverage and discuss validity issues; we believe that no serious biases have affected the validity of our vaccine coverage data but comparisons with international data must be addressed with caution; the methods we used have been useful in increasing vaccination coverage

    Qualitative analysis of a scalar-tensor theory with exponential potential

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    A qualitative analysis of a scalar-tensor cosmological model, with an exponential potential for the scalar field, is performed. The phase diagram for the flat case is constructed. It is shown that solutions with an initial and final inflationary behaviour appear. The conditions for which the scenario favored by supernova type Ia observations becomes an attractor in the space of the solutions are established.Comment: Latex file, 9 pages, 1 figur

    Development and use of a new medium to detect yeasts of the genera Dekkera/Brettanomyces

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    Aims: The objectives of this work were to develop a selective and/or differential medium able to effciently recover Dekkera/Brettanomyces sp. from wine-related environments and to determine the relationship between these yeasts and the 4-ethylphenol content in a wide range of wines. Methods and Results: The selectivity of the developed medium was provided by the addition of ethanol, as single carbon source, and cycloheximide. The inclusion of bromocresol green evidenced acid-producing strains. The inclusion of p-coumaric acid, substrate for the production of 4-ethylphenol, enabled the differentiation by smell of Dekkera/Brettanomyces sp. from all other yeast species growing in the medium. The medium was used either by plating after membrane filtration or by the Most Probable Number (MPN) technique. In 29 white and 88 red randomly collected wines, these yeasts were found only in red wines at levels up to 2500 MPN ml±1, but constituted less than 1% of the total microbial flora. In red wines, 84% showed detectable amounts of 4-ethylphenol up to 4430 lg l±1 while 28% of the white wines showed detectable levels up to 403 lg l±1. Conclusions: The use of the medium proposed in this work evidenced the presence of low relative populations of Dekkera/Brettanomyces sp. even in wines contaminated by fast-growing yeasts and moulds. Significance and Impact of the Study: Further ecological studies on Dekkera/Brettanomyces sp. should take into account the use of highly specific culture media in order to establish their true occurrence in natur

    Proposal of a New Standardized Freeze-Thawing Technical Protocol for Leucocyte-Poor Platelet-Rich Plasma Preparation and Cryopreservation

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    A human platelet-rich plasma (PRP) concentrate can be defined as a preparation of autologous human plasma with increased platelet concentration produced by centrifugation of a larger volume of a patient's own blood. Platelets contain a plethora of growth factors in their α-granules that are concentrated through the centrifugation process in order to then be injected in supraphysiologic amounts to an injury site with the final aim of augmenting the natural healing process. Preparations of PRP concentrates can be further classified as leucocyte-rich (LR-PRP), defined as having a leucocyte concentration above baseline, and leucocyte-poor (LP-PRP), defined as having a leucocyte concentration below baseline. Although many preclinical and clinical trials have shown the ability of leucocyte-poor PRP concentrates to significantly improve symptomatic mild to moderate hip and/or knee osteoarthritis, to date there is no consensus on the optimal way of obtaining PRP preparations, specifically with respect to the concentration of blood components. In this technical report, we describe a new standardized freeze-thawing technique for leucocyte-poor PRP preparation and cryopreservation, which has been shown to be superior to currently available techniques based solely on centrifugation. By describing this technical protocol, which we have been using on a daily basis in the setting of a Regenerative Medicine Outpatient Clinic in a European tertiary university hospital center, we aim to contribute to a future consensus on the optimal way of obtaining and preserving leucocyte-poor PRP concentrates.info:eu-repo/semantics/publishedVersio

    Mesenchymal Stromal Cell Secretome: Influencing Therapeutic Potential by Cellular Pre-conditioning

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    Mesenchymal stromal cells (MSCs) are self-renewing, culture-expandable adult stem cells that have been isolated from a variety of tissues, and possess multipotent differentiation capacity, immunomodulatory properties, and are relatively non-immunogenic. Due to this unique set of characteristics, these cells have attracted great interest in the field of regenerative medicine and have been shown to possess pronounced therapeutic potential in many different pathologies. MSCs' mode of action involves a strong paracrine component resulting from the high levels of bioactive molecules they secrete in response to the local microenvironment. For this reason, MSCs' secretome is currently being explored in several clinical contexts, either using MSC-conditioned media (CM) or purified MSC-derived extracellular vesicles (EVs) to modulate tissue response to a wide array of injuries. Rather than being a constant mixture of molecular factors, MSCs' secretome is known to be dependent on the diverse stimuli present in the microenvironment that MSCs encounter. As such, the composition of the MSCs' secretome can be modulated by preconditioning the MSCs during in vitro culture. This manuscript reviews the existent literature on how preconditioning of MSCs affects the therapeutic potential of their secretome, focusing on MSCs' immunomodulatory and regenerative features, thereby providing new insights for the therapeutic use of MSCs' secretome.We would like to acknowledge Norte Portugal Regional Operational Programme (NORTE 2020) in the framework of the project “Bioengineered Therapies for Infectious Diseases and Tissue Regeneration” (NORTE-01-0145-FEDER-000012). We also acknowledge Fundação para a Ciência e a Tecnologia (FCT) and Fundo Europeu de Desenvolvimento Regional (FEDER) funds through the COMPETE 2020-Operacional Programme for Competitiveness and Internationalization (POCI), Portugal 2020-in the framework of the project “Institute for Research and Innovation in Health Sciences” (POCI-01-0145-FEDER-007274). We also acknowledge EUROSPINE TRF for the funded project “Disc Regeneration, Immuno, and Neuro Modulation” , ref. 2017_05 . In addition, JF and RG also acknowledge FCT for funding the BiotechHealth Ph.D. fellowship (PD/BD/135486/2018) and the FCT Investigator Grant (IF/00638/2014), respectively
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