946 research outputs found

    Elastic electron scattering from 3-hydroxytetrahydrofuran: experimental and theoretical studies

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    We report the results of measurements and calculations for elastic electron scattering from 3-hydroxytetrahydrofuran (C4H8O2). The measurements are performed with a crossed electron-target beam apparatus and the absolute cross-sections are determined using the relative flow technique. The calculations are carried out using the Schwinger multichannel method in the static-exchange plus polarization (SEP) approximation. A set of angular differential cross-sections (DCS) is provided at five incident energies (6.5, 8, 10, 15 and 20 eV) over an angular range of 20–130°, and the energy dependence of the elastic DCS at a scattering angle of 120° is also presented. Integral elastic and elastic momentum transfer cross-sections have also been derived and calculated. The results are compared with those of recent measurements and calculations for the structurally similar molecule tetrahydrofuran (C4H8O)

    Mexican Trypanosoma cruzi T. cruzi I Strains with Different Degrees of Virulence Induce Diverse Humoral and Cellular Immune Responses in a Murine Experimental Infection Model

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    It is has been shown that the majority of T. cruzi strains isolated from Mexico belong to the T. cruzi I (TCI). The immune response produced in response to Mexican T. cruzi I strains has not been well characterized. In this study, two Mexican T. cruzi I strains were used to infect Balb/c mice. The Queretaro (TBAR/MX/0000/Queretaro)(Qro) strain resulted in 100% mortality. In contrast, no mortality was observed in mice infected with the Ninoa (MHOM/MX/1994/Ninoa) strain. Both strains produced extended lymphocyte infiltrates in cardiac tissue. Ninoa infection induced a diverse humoral response with a higher variety of immunoglobulin isotypes than were found in Qro-infected mice. Also, a stronger inflammatory TH1 response, represented by IL-12p40, IFNγ, RANTES, MIG, MIP-1β, and MCP-1 production was observed in Qro-infected mice when compared with Ninoa-infected mice. We propose that an exacerbated TH1 immune response is a likely cause of pathological damage observed in cardiac tissue and the primary cause of death in Qro-infected mice

    Effects of peroxisome proliferator-activated receptor-  activation in endothelin-dependent hypertension

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    Aims We analysed the chronic effects of the peroxisome proliferator-activated receptor β/δ (PPAR-β) agonist GW0742 on the renin-independent hypertension induced by deoxycorticosterone acetate (DOCA)-salt. Methods and results Rats were treated for 5 weeks with: control-vehicle, control-GW0742 (5 or 20 mg kg−1 day−1), DOCA-vehicle, DOCA-GW0742 (5 or 20 mg kg−1 day−1), DOCA-GSK0660 (1 mg kg−1 day−1), and DOCA-GSK0660-GW0742. Rats receiving DOCA-vehicle showed increased systolic blood pressure, left ventricular and kidney weight indices, endothelin-1 (ET-1), and malondialdehyde plasma levels, urinary iso-PGF2α excretion, impaired endothelium-dependent relaxation to acetylcholine, and contraction to ET-1 when compared with controls. Aortic reactive oxygen species content, NADPH oxidase activity, and p47phox, p22phox, NOX-4, glutathione peroxidase 1, hemeoxygenase-1, and preproET-1 expression were increased, whereas catalase and regulators of G protein-coupled signalling proteins (RGS)5 expression were decreased in the DOCA-vehicle group. GW0742 prevented the development of hypertension in a dose-dependent manner but the reduction of renal and cardiac hypertrophy, systemic and vascular oxidative stress markers, and improvement of endothelial dysfunction were only observed after the higher dose. GW0742, at 20 mg kg−1 day−1, attenuated ET-1 contraction by increasing RGS5 expression and restored the intracellular redox balance by reducing NADPH-oxidase activity, and by increasing the antioxidant genes expression. The PPAR-β antagonist GSK0660 prevented all vascular changes induced by GW0742 but not its antihypertensive effects. Conclusion Vascular protective effects of GW0742 operate via PPAR-β by interference with the ET-1 signalling as a result of increased expression of RGS5 and up-regulation of antioxidant genes and via PPAR-β-independent mechanisms to decrease blood pressure

    How people interact with a chatbot against disinformation and fake news in COVID-19 in Brazil: The CoronaAI case

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    Background: The search for valid information was one of the main challenges encountered during the COVID-19 pandemic, which resulted in the development of several online alternatives. Objectives: To describe the development of a computational solution to interact with users of different levels of digital literacy on topics related to COVID-19 and to map the correlations between user behavior and events and news that occurred throughout the pandemic. Method: CoronaAI, a chatbot based on Google's Dialogflow technology, was developed at a public university in Brazil and made available on WhatsApp. The dataset with users’ interactions with the chatbot comprises approximately 7,000 hits recorded throughout eleven months of CoronaAI usage. Results: CoronaAI was widely accessed by users in search of valuable and updated information on COVID-19, including checking the veracity of possible fake news about the spread of cases, deaths, symptoms, tests and protocols, among others. The mapping of users' behavior revealed that as the number of cases and deaths increased and as COVID-19 became closer, users showed a greater need for information applicable to self-care compared to following the statistical data. In addition, they showed that the constant updating of this technology may contribute to public health by enhancing general information on the pandemic and at the individual level by clarifying specific doubts about COVID-19. Conclusion: Our findings reinforce the potential usefulness of chatbot technology to resolve a wide spectrum of citizens' doubts about COVID-19, acting as a cost-effective tool against the parallel pandemic of misinformation and fake news

    Intra-abdominal pulmonary secuestration as an exceptional cause of abdominal mass in the adult

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    AbstractINTRODUCTIONPulmonary sequestration (PS) is an extremely rare malformation defined as a portion of lung tissue isolated from the pulmonary system. PSs are classified into intralobar type and intra-abdominal PS that represents only 2.5% of cases. There are 20 cases of PS reported in adults and only two were managed by laparoscopic approach. We report a case of intra-abdominal PS mimicking a gastroesophageal duplication cyst in an adult. Besides its rarity, this is the first intra-abdominal PS in an adult managed by an anterior laparoscopic approach.PRESENTATION OF CASEA 60-year-old female patient had had epigastric and left upper quadrant pain for several days. Physical examination was normal. Image test were consistent with a gastroesophageal duplication. The patient was taken to the operating room for laparoscopic exploration and resection. The pathological diagnosis was extralobar pulmonary sequestration.DISCUSSIONLess than 20 cases of PS have been reported in adults and only two cases were managed by a lateral laparoscopic approach. In contrast to these reports, we used an anterior approach due to the GEJ suspected origin of the mass.CONCLUSIONExtralobar intra-abdominal PS is an extremely rare condition during adulthood but this diagnosis should be included in the differential diagnosis of a left-sided suprarenal mass. Due to the difficulty in achieving a definitive preoperative diagnosis, surgery is recommended. Laparoscopic resection is safe and effective but careful preoperative imaging studies are recommended in order to plan the most suitable approach

    Electron scattering from molecules and molecular aggregates of biological relevance

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    In this Topical Review we survey the current state of the art in the study of low energy electron collisions with biologically relevant molecules and molecular clusters. We briefly describe the methods and techniques used in the investigation of these processes and summarise the results obtained so far for DNA constituents and their model compounds, amino acids, peptides and other biomolecules. The applications of the data obtained is briefly described as well as future required developments
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