157 research outputs found

    Performance and emission of pollutants of an agricultural engine with two-power take-off settings

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    Farming operations are usually performed implements driven by a power take-off (PTO) from tractors. Some manufacturers offer PTO settings named as economic (540E). Such configuration drives implements at lower tractor’s engine rotation, thus providing lower fuel consumption. An engine performance using standard (540) or 540E settings are different and poorly studied. The amounts of pollutants emitted by engines vary mainly with the applied load and rotation. The aim of this study was to compare the performance and exhaust emissions of a farming tractor engine under different PTO loads, using both standard (540) and 540E settings. Specific fuel consumption using 540E was an average 14.7% less than the standard setting. However, 540E promoted increasing levels of gas opacity, CO, CO2, NOx, and HC for the highest PTO power demands.Postprint (published version

    Resíduo de cerâmica vermelha e fíler calcário em compósito de cimento Portland: efeito no ataque por sulfatos e na reação álcali-sílica

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    O resíduo de cerâmica vermelha (RCV) proveniente de blocos e tijolos é gerado na produção destes artefatos e na indústria da construção civil, quando da execução das vedações verticais. No primeiro caso, o resíduo apresenta menor teor de contaminantes, enquanto no segundo, o resíduo contém maior grau de impurezas devido à estocagem com outros materiais residuais previamente à destinação final. O volume de RCV gerado requer adequada destinação para evitar impactos ambientais, conforme estabelece a Resolução 307 do Conse-lho Nacional do Meio Ambiente (CONAMA). A potencialidade reativa do RCV com a cal o qualifica para o uso como adição mineral na composição do cimento Portland evitando, assim, a disposição em aterros desti-nados à resíduos de construção civil. A análise da viabilidade da incorporação do RCV ao cimento Portland requer estudos que envolvam os efeitos sobre a resistência à compressão e, sobretudo, sobre o desempenho da matriz hidratada quando susceptível à ação de interações físico-químicas deletérias. O presente trabalho tem por objetivo avaliar a influência da incorporação do RCV moído na composição do cimento Portland sobre duas propriedades relacionadas à durabilidade do concreto: resistência à ocorrência de reação álcali-sílica (RAS) e resistência ao ataque por sulfato de sódio. Para isto, argamassas de cimento CP V -- ARI (refe-rência) e composições com a substituição de 10% do cimento, em massa, por fíler calcário ou RCV, com três diferentes finuras, foram avaliadas quanto à RAS, segundo a NBR 15.577-5/2008, e à expansão decorrente do ataque por sulfato de sódio, conforme a NBR 13.583/2014, com tempos de exposição estendidos para uma avaliação mais criteriosa da degradação. Os resultados evidenciam que o RCV causou aumento na expansão por RAS e, na maior parte dos casos, também aumentou a expansão devido ao ataque por sulfato de sódio. Por outro lado, a maior cominuição do RCV tende a melhorar o desempenho da matriz cimentícia frente às ações deletérias a que foi submetida, ou seja, a maior finura do RCV impacta, positivamente, no comporta-mento do material frente à degradação. O fíler calcário não influenciou o resultado de expansão por RAS e propiciou redução da expansão provocada pelo ataque por sulfato de sódio. A análise em tempos prolongados de exposição (66 dias para o ensaio de RAS e 210 dias para o ensaio de ataque por sulfato) evidenciou que o RCV moído por 1,5 horas possui potencialidade para a sua utilização como adição mineral na composição do material ligante, com tendência a apresentar desempenho similar à matriz de cimento Portland frente ao ata-que por sulfato. Com relação à RAS, há que se incrementar a cominuição do RCV moído por 1,5 horas para aproximar, ao máximo, a sua distribuição granulométrica à distribuição do cimento, o que tende a potenciali-zar a capacidade mitigadora desta adição mineral

    A novel approach for the characterisation of proteoglycans and biosynthetic enzymes in a snail model

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    Proteoglycans encompass a heterogeneous group of glycoconjugates where proteins are substituted with linear, highly negatively charged glycosaminoglycan chains. Sulphated glycosaminoglycans are ubiquitous to the animal kingdom of the Eukarya domain. Information on the distribution and characterisation of proteoglycans in invertebrate tissues is limited and restricted to a few species. By the use of multidimensional protein identification technology and immunohistochemistry, this study shows for the first time the presence and tissue localisation of different proteoglycans, such as perlecan, aggrecan, and heparan sulphate proteoglycan, amongst others, in organs of the gastropoda Achatina fulica. Through a proteomic analysis of Golgi proteins and immunohistochemistry of tissue sections, we detected the machinery involved in glycosaminoglycan biosynthesis, related to polymer formation (polymerases), as well as secondary modifications (sulphation and uronic acid epimerization). Therefore, this work not only identifies both the proteoglycan core proteins and glycosaminoglycan biosynthetic enzymes in invertebrates but also provides a novel method for the study of glycosaminoglycan and proteoglycan evolution. (C) 2011 Elsevier B.V. All rights reserved.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)NIHUniversidade Federal de São Paulo, Dept Bioquim, BR-04044020 São Paulo, BrazilUniv Texas El Paso, Dept Biol Sci, Border Biomed Res Ctr, El Paso, TX 79912 USAUniversidade Federal de São Paulo, Dept Bioquim, BR-04044020 São Paulo, BrazilNIH: 2G12RR008124-16A1NIH: 2G12RR008124-16A1S1Web of Scienc

    Evaluation of 3-(3-chloro-phenyl)-5-(4-pyridyl)-4,5-dihydroisoxazole as a Novel Anti-Inflammatory Drug Candidate

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    BACKGROUND: 3-(3-chloro-phenyl)-5-(4-pyridyl)-4,5-dihydroisoxazole (DIC) is a five-membered heterocyclic compound containing a N-O bond. The anti-inflammatory effects of this compound were studied both in vitro and in vivo. PRINCIPAL FINDINGS: DIC effectively decreased TNF-α and IL-6 release from LPS-stimulated macrophages in a dose dependent manner. DIC diminished the levels of COX-2 with subsequent inhibition of PGE(2) production. DIC also compromised HMGB1 translocation from the nucleus to the cytoplasm. Moreover, DIC prevented the nuclear translocation of NF-κB and inhibited the MAPK pathway. In vivo, DIC inhibited migration of neutrophils to the peritoneal cavity of mice. CONCLUSIONS: This study presents the potential utilization of a synthetic compound, as a lead for the development of novel anti-inflammatory drugs

    A New Approach for Heparin Standardization: Combination of Scanning UV Spectroscopy, Nuclear Magnetic Resonance and Principal Component Analysis

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    The year 2007 was marked by widespread adverse clinical responses to heparin use, leading to a global recall of potentially affected heparin batches in 2008. Several analytical methods have since been developed to detect impurities in heparin preparations; however, many are costly and dependent on instrumentation with only limited accessibility. A method based on a simple UV-scanning assay, combined with principal component analysis (PCA), was developed to detect impurities, such as glycosaminoglycans, other complex polysaccharides and aromatic compounds, in heparin preparations. Results were confirmed by NMR spectroscopy. This approach provides an additional, sensitive tool to determine heparin purity and safety, even when NMR spectroscopy failed, requiring only standard laboratory equipment and computing facilities

    Geographic patterns of tree dispersal modes in Amazonia and their ecological correlates

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    Unidad de excelencia María de Maeztu CEX2019-000940-MAim: To investigate the geographic patterns and ecological correlates in the geographic distribution of the most common tree dispersal modes in Amazonia (endozoochory, synzoochory, anemochory and hydrochory). We examined if the proportional abundance of these dispersal modes could be explained by the availability of dispersal agents (disperser-availability hypothesis) and/or the availability of resources for constructing zoochorous fruits (resource-availability hypothesis). Time period: Tree-inventory plots established between 1934 and 2019. Major taxa studied: Trees with a diameter at breast height (DBH) ≥ 9.55 cm. Location: Amazonia, here defined as the lowland rain forests of the Amazon River basin and the Guiana Shield. Methods: We assigned dispersal modes to a total of 5433 species and morphospecies within 1877 tree-inventory plots across terra-firme, seasonally flooded, and permanently flooded forests. We investigated geographic patterns in the proportional abundance of dispersal modes. We performed an abundance-weighted mean pairwise distance (MPD) test and fit generalized linear models (GLMs) to explain the geographic distribution of dispersal modes. Results: Anemochory was significantly, positively associated with mean annual wind speed, and hydrochory was significantly higher in flooded forests. Dispersal modes did not consistently show significant associations with the availability of resources for constructing zoochorous fruits. A lower dissimilarity in dispersal modes, resulting from a higher dominance of endozoochory, occurred in terra-firme forests (excluding podzols) compared to flooded forests. Main conclusions: The disperser-availability hypothesis was well supported for abiotic dispersal modes (anemochory and hydrochory). The availability of resources for constructing zoochorous fruits seems an unlikely explanation for the distribution of dispersal modes in Amazonia. The association between frugivores and the proportional abundance of zoochory requires further research, as tree recruitment not only depends on dispersal vectors but also on conditions that favour or limit seedling recruitment across forest types

    Local hydrological conditions influence tree diversity and composition across the Amazon basin

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    Tree diversity and composition in Amazonia are known to be strongly determined by the water supplied by precipitation. Nevertheless, within the same climatic regime, water availability is modulated by local topography and soil characteristics (hereafter referred to as local hydrological conditions), varying from saturated and poorly drained to well-drained and potentially dry areas. While these conditions may be expected to influence species distribution, the impacts of local hydrological conditions on tree diversity and composition remain poorly understood at the whole Amazon basin scale. Using a dataset of 443 1-ha non-flooded forest plots distributed across the basin, we investigate how local hydrological conditions influence 1) tree alpha diversity, 2) the community-weighted wood density mean (CWM-wd) – a proxy for hydraulic resistance and 3) tree species composition. We find that the effect of local hydrological conditions on tree diversity depends on climate, being more evident in wetter forests, where diversity increases towards locations with well-drained soils. CWM-wd increased towards better drained soils in Southern and Western Amazonia. Tree species composition changed along local soil hydrological gradients in Central-Eastern, Western and Southern Amazonia, and those changes were correlated with changes in the mean wood density of plots. Our results suggest that local hydrological gradients filter species, influencing the diversity and composition of Amazonian forests. Overall, this study shows that the effect of local hydrological conditions is pervasive, extending over wide Amazonian regions, and reinforces the importance of accounting for local topography and hydrology to better understand the likely response and resilience of forests to increased frequency of extreme climate events and rising temperatures
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