1,025 research outputs found

    Sedimentation and Erosion in Harbor Estuaries

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    Harbors, whenever possible, are established in estuaries to take advantage of the existing natural safety and protection conditions. To keep harbors in a safe and usable way, periodic dredging works are carried out. The expansion of harbor’s activities and the growth of maritime traffic may lead to changes in the harbor’s layout or to improvements of navigation channels and basin depths. Such design adjustments entail changes in estuarine hydrodynamics, and therefore the usual dredging rates are subject to alteration, namely, tending to increase. It is then important to assess the influence of the harbor’s new layout on the solid transport pattern and how its effects can be minimized, aiming the reduction of economic and environmental impacts. Within this context, in this chapter estuary hydrodynamics and sedimentation-erosion patterns are summarized. Also, the modeling methodology for planning and management of dredging works which uses geo-processing automatic GIS environment, developed by the Portuguese harbor authority, is presented. Finally, the case study of harbor of Portimão is also described showing the implementation of the referred methodology

    Pristine Multi-walled carbon nanotubes for a rapid and efficient plasmid DNA clarification

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    Therapeutic approaches based on nucleic acids to modulate cell activity have recently gained attention. These molecules arise from complex biotechnological processes, requiring effective manufacturing strategies, high purity, and precise quality control to be used as biopharmaceuticals. One of the most critical and time-consuming steps for nucleic acids-based biotherapeutics manufacturing is their purification, mainly due to the complexity of the extracts. In this study, a simple, efficient, and reliable method to isolate and clarify plasmid DNA (pDNA) from complex samples is described. The method is based on the selective capture of RNA and other impurities, using pristine carbon nanotubes (CNTs). Multi-walled CNTs (MWCNTs) with different diameters were studied to determine their adsorption capacity and to address their ability to interact and distinguish between nucleic acids. The results revealed that MWCNTs preferentially interact with RNA and that smaller MWCNTs present a higher adsorption capacity, as expected by the higher specific surface area. Overall, this study showed that MWCNTs significantly reduce the levels of impurities, namely RNA, gDNA, and proteins, by approximately 83.6 % compared to their initial level, enabling the recovery of clarified pDNA in solution while maintaining its stability throughout the recovery process. This method facilitates the pre-purification of pDNA for therapeutic applications.publishe

    Short Telomeres in Key Tissues Initiate Local and Systemic Aging in Zebrafish.

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    Telomeres shorten with each cell division and telomere dysfunction is a recognized hallmark of aging. Tissue proliferation is expected to dictate the rate at which telomeres shorten. We set out to test whether proliferative tissues age faster than non-proliferative due to telomere shortening during zebrafish aging. We performed a prospective study linking telomere length to tissue pathology and disease. Contrary to expectations, we show that telomeres shorten to critical lengths only in specific tissues and independently of their proliferation rate. Short telomeres accumulate in the gut but not in other highly proliferative tissues such as the blood and gonads. Notably, the muscle, a low proliferative tissue, accumulates short telomeres and DNA damage at the same rate as the gut. Together, our work shows that telomere shortening and DNA damage in key tissues triggers not only local dysfunction but also anticipates the onset of age-associated diseases in other tissues, including cancer

    Inhibition Of Epithelial-mesenchymal Transition And Metastasis By Combined Tgfbeta Knockdown And Metformin Treatment In A Canine Mammary Cancer Xenograft Model

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    Epithelial mesenchymal transition (EMT) is a process by which epithelial cells acquire mesenchymal properties, generating metastases. Transforming growth factor beta (TGF-β) is associated with this malignancy by having the ability to induce EMT. Metformin, has been shown to inhibit EMT in breast cancer cells. Based on this evidence we hypothesize that treatment with metformin and the silencing of TGF-β, inhibits the EMT in cancer cells. Canine metastatic mammary tumor cell line CF41 was stably transduced with a shRNA-lentivirus, reducing expression level of TGF-β1. This was combined with metformin treatment, to look at effects on cell migration and the expression of EMT markers. For in vivo study, unmodified or TGF-β1sh cells were injected in the inguinal region of nude athymic female mice followed by metformin treatment. The mice’s lungs were collected and metastatic nodules were subsequently assessed for EMT markers expression. The migration rate was lower in TGF-β1sh cells and when combined with metformin treatment. Metformin treatment reduced N-cadherin and increased E-cadherin expression in both CF41 and TGF-β1sh cells. Was demonstrated that metformin treatment reduced the number of lung metastases in animals bearing TGF-β1sh tumors. This paralleled a decreased N-cadherin and vimentin expression, and increased E-cadherin and claudin-7 expression in lung metastases. This study confirms the benefits of TGF-β1 silencing in addition to metformin as potential therapeutic agents for breast cancer patients, by blocking EMT process. To the best of our knowledge, we are the first to report metformin treatment in cells with TGF-β1 silencing and their effect on EMT. © 2017, Springer Science+Business Media New York.221274

    Correction: Telomerase is required for zebrafish lifespan

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    [This corrects the article DOI: 10.1371/journal.pgen.1003214.]

    Prevalence of newcastle disease virus in broiler chickens (Gallus gallus) in Brazil

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    This study was carried out during 2002/2003, aiming to determine the prevalence of virulent Newcastle disease virus strains (NDV) in Brazilian commercial poultry farms. Clinical samples were obtained from the Southeastern, Southern and Central-Western regions, which comprise the main area of the Brazilian poultry production. Serum samples and tracheal and cloacal swabs of 23,745 broiler chickens from 1,583 flocks, including both vaccinated chickens and those with no vaccination information, were tested for NDV using a diagnostic ELISA kit. The seropositivity was 39.1%, and the isolation percentage by flock varied from 1.0 to 7.6%, and by region from 6.5 to 58.4%. Higher isolation rates (74.3-83.3%) were obtained after three passages in embryonated chicken eggs. All isolates preliminarily identified as NDV were characterized as nonpathogenic strains, as their Intracerebral Pathogenicity Index (ICPI) was below 0.7. Based on results of this study, Brazil can claim a virulent NDV-free status for commercial flocks.349357Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

    A survey for maintenance of virulent newcastle disease virus-free area in poultry production in Brazil

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    In 2003, Brazil was recognized as a pathogenic Newcastle Disease Virus (NDV) strain-free country for commercial poultry. This research was conducted in Brazil between December 2003 and March 2005 to verify the maintenance of this virulent NDV-free status. Serum samples from 5,455 flocks for commercial poultry farms were collected, comprising 81,825 broiler chickens. The farms were located in nine states of the country, grouped in three geographic regions. Serological evidence of NDV infection was detected in 28.8% of the surveyed farms. However, all fifteen viruses isolated and identified as Newcastle Disease Virus (NDV) were characterized as nonpathogenic strains, based on the Intracerebral Pathogenicity Index. These results showed that Brazil preserves the virulent NDV-free status for commercial flocks.368375Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

    Electron-beam irradiation preserves nutritional profile of Agaricus bisporus Portobello

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    All over the world, mushrooms are highly consumed due to their high contents of digestible proteins, carbohydrates, vitamins and fibers. Mushrooms contain about 90% of water, which leads to a faster deterioration due to senescence, browning, water loss and microbial attack. Despite of the immense popularity of this food worldwide, data regarding alternative technologies to increase mushrooms shelf-life are scarce. Ionizing radiation processing is recognized as a safe and effective method for conservation, being widely used to extend the shelf-life of raw foods. The present work reports the effects of storage time (0, 4 and 8 days) and electron-beam irradiation on the nutritional composition (moisture, fat, proteins, ash, carbohydrates and energy) of Agaricus bisporus Portobello samples. The irradiation was performed with a 10 MeV energy irradiator at the doses of 1, 2 and 5 kGy. The proximate composition was evaluated by AOAC official procedures. Storage time (ST) and electron-beam (EB) irradiation showed a significant interaction in all cases (p-value > 0.05), indicating that the effects potentially exerted by ST depended on EB dose and vice-versa. Considering the individual effect of each factor, EB induced more changes than ST, which in fact had a significant effect only for protein and carbohydrates. Among different EB doses, despite the significant differences, it is evident that the nutritional profiles were not greatly changed with any applied dose. Therefore, up to 5 kGy, EB seems to be a suitable conservation treatment for A. bisporus Portobello.Foundation for Science and Technology (FCT, Portugal) and FEDER under Programme PT2020 for financial support to CIMO (UID/AGR/00690/2013), C2TN (UID/Multi/04349/2013), grant to A. Fernandes (SFRH/BPD/114753/2016) and L. Barros contract; European Structural and Investment Funds (ESIF) (Regional Operational Program Norte 2020, Project ValorNatural®); Rural Development Program (Project MicoCoating, PDR2020-101-031472); International Atomic Energy Agency (IAEA) Coordinated Research Project D61024 DEXAFI.info:eu-repo/semantics/publishedVersio

    Male infertility in the XXI century: are obesogens to blame?

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    The permanent exposure to environmental contaminants promoting weight gain (i.e., obesogens) has raised serious health concerns. Evidence suggests that obesogens are one of the leading causes of the marked decline in male fertility and are key players in shaping future health outcomes, not only for those who are directly exposed to them, but also for upcoming generations. It has been hypothesized that obesogens affect male fertility. By using an interdisciplinary strategy, combining in silico, in vitro, in vivo and epidemiological findings, this review aims to contribute to the biological understanding of the molecular transformations induced by obesogens that are the basis of male infertility. Such understanding is shaped by the use of Adverse Outcomes Pathways, a new approach that may shift the paradigm of reproductive toxicology, contributing to the improvement of the diagnosis and management of the adverse effects of obesogens in male fertility
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