872 research outputs found

    Social representations on remote teaching during covid-19 pandemic in teenage students in a non-bilingual public school in Barranquilla, Colombia

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    This article presents the results of a research aimed at understanding the social representations of secondary school students about English classes during the Covid-19 pandemic in an educational institution in Barranquilla. The process of digital adoption of methodologies and tools in the pandemic lead to new conditions and dynamics for the development of classes which in turn, trigger changes in school achievement, performance and learning experiences. The present research involved 8th grade students who had experienced the temporary change from face-to-face to remote English classes. The method used was the structural approach of social representations, along free association techniques to describe its contents, and hierarchization techniques complemented to Likert-type scales to create a hypothesis about the central core. The results show that the most salient element is attitudes, significantly polarized between approval and disapproval of remote English classes, with "Learning", "Fun", "Easy", as well as "Difficult", "Complicated" or "Stressful" being central terms. The findings point to the need to explore further the heterogeneity of students' conditions of access to technology, and their personal experiences, which would merit future studies based on such experiences.MaestríaMagister en la Enseñanza del Ingle

    DIS3L2 knockdown impairs key oncogenic properties of colorectal cancer cells via the mTOR signaling pathway

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    DIS3L2 degrades different types of RNAs in an exosome-independent manner including mRNAs and several types of non-coding RNAs. DIS3L2-mediated degradation is preceded by the addition of nontemplated uridines at the 3’end of its targets by the terminal uridylyl transferases 4 and 7. Most of the literature that concerns DIS3L2 characterizes its involvement in several RNA degradation pathways, however, there is some evidence that its dysregulated activity may contribute to cancer development. In the present study, we characterize the role of DIS3L2 in human colorectal cancer (CRC). Using the public RNA datasets from The Cancer Genome Atlas (TCGA), we found higher DIS3L2 mRNA levels in CRC tissues versus normal colonic samples as well as worse prognosis in patients with high DIS3L2 expression. In addition, our RNA deep-sequencing data revealed that knockdown (KD) of DIS3L2 induces a strong transcriptomic disturbance in SW480 CRC cells. Moreover, gene ontology (GO) analysis of significant upregulated transcripts displays enrichment in mRNAs encoding proteins involved in cell cycle regulation and cancer-related pathways, which guided us to evaluate which specific hallmarks of cancer are differentially regulated by DIS3L2. To do so, we employed four CRC cell lines (HCT116, SW480, Caco-2 and HT-29) differing in their mutational background and oncogenicity. We demonstrate that lack depletion of DIS3L2 results in reduced cell viability of highly oncogenic SW480 and HCT116 CRC cells, but had little or no impact in the more differentiated Caco-2 and HT-29 cells. Remarkably, the mTOR signaling pathway, crucial for cell survival and growth, is downregulated after DIS3L2 KD, whereas AZGP1, an mTOR pathway inhibitor, is upregulated. Furthermore, our results indicate that depletion of DIS3L2 disturbs metastasis-associated properties, such as cell migration and invasion, only in highly oncogenic CRC cells. Our work reveals for the first time a role for DIS3L2 in sustaining CRC cell proliferation and provides evidence that this ribonuclease is required to support the viability and invasive behavior of dedifferentiated CRC cells.This work was supported by Instituto Nacional de Saúde Doutor Ricardo Jorge and Fundação para a Ciência e a Tecnologia (FCT) [UID/MULTI/04046/2019 Research Unit Grant (to BioISI)]. Juan F. García-Moreno and Paulo J. da Costa were recipients of a fellowship from BioSys PhD programme (SFRH/BD/52495/2014, and PD/BD/142898/2018, respectively).info:eu-repo/semantics/publishedVersio

    Control vía Internet de un robot ubicado en un sitio remoto aplicando una interfase cerebro-máquina

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    En este artículo se describe el trabajo de investigación que en la actualidad se está desarrollando dentro del área de la comunicación de humanos a robots, sobre la base de bioseñales cerebrales y puntualmente en sitios remotos. Para esta investigación se aplican tecnologías, interfases disponibles y protocolos de comunicación estándar que facilitan la lectura de las señales del cerebro del usuario, su asociación a comandos explícitos y la comunicación entre los sitios remotos.Presentado en el II Workshop Procesamiento de Señales y Sistemas de Tiempo Real (WPSTR)Red de Universidades con Carreras en Informática (RedUNCI

    Proof-of-Concept Studies Directed toward the Formation of Metallic Ag Nanostructures from Ag3PO4 Induced by Electron Beam and Femtosecond Laser

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    In this work, for the first time, the instantaneous nucleation and growth processes of Ag nanoparticles on Ag3PO4 mediated by femtosecond laser pulses are reported and analyzed. The investigated samples are pure Ag3PO4sample, electron-irradiated Ag3PO4 sample, and laser-irradiated sample. Complete characterization of the samples is performed using X-ray diffraction (XRD), Rietveld refinements, field emission scanning electron microscopy, and energy dispersive spectroscopy (EDS). XRD confirms that the irradiated surface layer remains crystalline, and according to EDS analysis, the surface particles are composed primarily of Ag nanoparticles. This method not only offers a one-step route to synthesize Ag nanoparticles using laser-assisted irradiation with particle size control, but also reports a complex process involving the formation and subsequent growth of Ag nanoparticles through an unexpected additive-free in situ fabrication process

    Efficacy and safety of a double-coated paclitaxel-eluting coronary stent: The EUCATAX trial

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    Objectives: The aim of this study was the comparison of a new double-coated paclitaxel-eluting coronary stent with bare-metal stent (BMS) in patients undergoing percutaneous coronary intervention. Background: Stent coating with biodegradable polymers as a platform for elution of drugs has the potential for complete elution of drugs and for decreasing the risk of late complications. Methods: Multicenter randomized trial comparing a paclitaxel-eluting stent (PES) coated with a biodegradable polymer and glycocalyx with the equivalent BMS. We randomly assigned 422 patients with de novo coronary lesions to PES (211 patients) or to BMS (211 patients). Primary end point was target vessel failure (TVF) defined as cardiac death, myocardial infarction, and target vessel revascularization. Clinical secondary end points were target vessel revascularization, target lesion revascularization, stent thrombosis (ST), and major adverse cardiovascular events (MACE). Angiographic secondary end points were late loss and binary restenosis. Results: At 1 year of follow-up, TVF rate was 9.5% in the PES group and 17.1% in the BMS group (P = 0.02), and MACE rate was 10% in PES and 19% in BMS arm (P = 0.009). All other secondary end points were reached but ST. ST rate was low and similar in both study arms. Conclusions: The study shows that patients treated with PES with dual coating technology had significantly lower incidence of TVF and MACE than those treated with BMS design; however, longer follow-up should be necessary to assess true advantages of this technology compared with the previous one.Fil: Rodriguez, Alfredo E.. Sanatorio "Otamendi y Miroli S. A."; ArgentinaFil: Vigo, Cesar F.. Sanatorio del Salvador S. A.; ArgentinaFil: Delacasa, Alejandro. Sanatorio Belgrano; ArgentinaFil: Mieres, Juan. Sanatorio "Otamendi y Miroli S. A."; ArgentinaFil: Fernandez Pereira, Carlos. Sanatorio "Otamendi y Miroli S. A."; ArgentinaFil: Bernardi, Victor. Clinica del Sol;Fil: Bettinoti, Marcelo. Sanatorio Guemes Sociedad Anonima.; ArgentinaFil: Rodriguez Granillo, Gaston Alfredo. Sanatorio "Otamendi y Miroli S.A.". Servicio de Diagnóstico por Imágenes. Departamento de Imágenes en Cardiología. Centro de Investigaciones Cardiovasculares; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Curotto, Valeria. Sanatorio "Otamendi y Miroli S. A."; ArgentinaFil: Rubilar, Bibiana. Sanatorio "Otamendi y Miroli S. A."; ArgentinaFil: Tronge, Jorge. No especifíca;Fil: Palacios, Igor F.. Massachusetts General Hospital; Estados UnidosFil: Antoniucci, David. Careggi Hospital; Itali

    Experimental and Theoretical Study of SbPO4 under Compression

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    This document is the Accepted Manuscript version of a Published Work that appeared in final form in Inorganic Chemistry, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see https://doi.org/10.1021/acs.inorgchem.9b02268.[EN] SbPO4 is a complex monoclinic layered material characterized by a strong activity of the nonbonding lone electron pair (LEP) of Sb. The strong cation LEP leads to the formation of layers piled up along the a axis and linked by weak SbO electrostatic interactions. In fact, Sb has 4-fold coordination with O similarly to what occurs with the P-O coordination, despite the large difference in ionic radii and electronegativity between both elements. Here we report a joint experimental and theoretical study of the structural and vibrational properties of SbPO4 at high pressure. We show that SbPO4 is not only one of the most compressible phosphates but also one of the most compressible compounds of the ABO(4) family. Moreover, it has a considerable anisotropic compression behavior, with the largest compression occurring along a direction close to the a axis and governed by the compression of the LEP and the weak interlayer Sb-O bonds. The strong compression along the a axis leads to a subtle modification of the monoclinic crystal structure above 3 GPa, leading from a 2D to a 3D material. Moreover, the onset of a reversible pressure-induced phase transition is observed above 9 GPa, which is completed above 20 GPa. We propose that the high-pressure phase is a triclinic distortion of the original monoclinic phase. The understanding of the compression mechanism of SbPO4 can aid to improve the ion intercalation and catalytic properties of this layered compound.The authors acknowledge financial support from the Brazilian Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq - 159754/2018-6, 307199/2018-5, 422250/20163, 201050/2012-9), FAPESP (2013/07793-6), Spanish Ministerio de Economia y Competitividad (MINECO) under projects MALTA Consolider Ingenio 2010 network (MAT2015-71070-REDC and RED2018-102612-T), MAT2016-75586-C4-1/2/3-P, PGC2018-097520-A-I00, FIS2017-83295-P, and PGC2018-094417-B-I00 from Generalitat Valenciana under project PROMETEO/2018/123, and the European Comission under project COMEX. D.S.-P., JA.S., and A.O.d.l.R. acknowledge "Ramim y Cajal" Fellowships for financial support (RyC-2014-15643, RYC-2015-17482, and RyC-2016-20301, respectively). E.L.d. S., A.M., A.B., and P.R-.H. acknowledge computing time provided by Red Espanola de SupercomputaciOn (RES) and MALTA-Cluster.Pereira, ALDJ.; Santamaria-Pérez, D.; Vilaplana Cerda, RI.; Errandonea, D.; Popescu, C.; Da Silva, EL.; Sans-Tresserras, JÁ.... (2020). Experimental and Theoretical Study of SbPO4 under Compression. Inorganic Chemistry. 59(1):287-307. https://doi.org/10.1021/acs.inorgchem.9b02268S287307591Falcão Filho, E. L., Bosco, C. A. C., Maciel, G. S., de Araújo, C. B., Acioli, L. H., Nalin, M., & Messaddeq, Y. (2003). Ultrafast nonlinearity of antimony polyphosphate glasses. Applied Physics Letters, 83(7), 1292-1294. doi:10.1063/1.1601679Nalin, M., Poulain, M., Poulain, M., Ribeiro, S. J. ., & Messaddeq, Y. (2001). Antimony oxide based glasses. Journal of Non-Crystalline Solids, 284(1-3), 110-116. doi:10.1016/s0022-3093(01)00388-xNalin, M., Messaddeq, Y., Ribeiro, S. J. L., Poulain, M., Briois, V., Brunklaus, G., … Eckert, H. (2004). 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Physical Review B, 81(6). doi:10.1103/physrevb.81.064113Errandonea, D., Gomis, O., Rodríguez-Hernández, P., Muñoz, A., Ruiz-Fuertes, J., Gupta, M., … Bettinelli, M. (2018). High-pressure structural and vibrational properties of monazite-type BiPO4, LaPO4, CePO4, and PrPO4. Journal of Physics: Condensed Matter, 30(6), 065401. doi:10.1088/1361-648x/aaa20dLópez-Solano, J., Rodríguez-Hernández, P., Muñoz, A., Gomis, O., Santamaría-Perez, D., Errandonea, D., … Raptis, C. (2010). Theoretical and experimental study of the structural stability ofTbPO4at high pressures. Physical Review B, 81(14). doi:10.1103/physrevb.81.144126Musselman, M. A., Wilkinson, T. M., Haberl, B., & Packard, C. E. (2018). In situ Raman spectroscopy of pressure‐induced phase transformations in polycrystalline Tb PO 4 , Dy PO 4 , and Gd x Dy (1− x ) PO 4. Journal of the American Ceramic Society, 101(6), 2562-2570. doi:10.1111/jace.15374Muñoz, A., & Rodríguez-Hernández, P. (2018). 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    Influência do material da ferramenta de corte sobre a usinabilidade do aço ABNT 4340 no torneamento

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    No presente trabalho procurou-se compreender os fenômenos associados à usinagem do aço ABNT 4340utilizando ferramentas de corte de metal duro e cermet, ambas com geometria do quebra-cavaco para usinagemleve (LP) e média (MP). Nesse sentido, analisou-se a influência da variação do avanço, quebracavacoe o material da ferramenta de corte nos parâmetros de resposta do processo, força de corte, rugosidade,forma do cavaco e análise das superfícies de saída e de folga dos insertos durante a operação de torneamento.Inicialmente, um planejamento fatorial completo 2³ foi empregado para análise da força de cortee rugosidade. Em relação à análise da força de corte, a análise de variância (ANOVA) indicou que o materialda ferramenta de corte e o avanço afetaram significativamente a força de corte, sendo os menores valoresalcançados com a ferramenta de corte cermet e o menor nível de avanço. Quanto à rugosidade Rq, diferentesníveis de materiais de ferramenta ou quebra-cavacos não foram suficientes para alterar significativamenteo valor de Rq. Em relação ao cavaco, o avanço e o tipo de quebra-cavaco influenciaram na sua forma.Como última análise, para os parâmetros de corte estabelecidos e percurso de corte, não foi possível identificardesgaste nas ferramentas de corte, no entanto, a análise por EDS apontou a adesão de material nassuperfícies de folga e de saída para ambas ferramentas avaliadas.Palavras-chave: aço ABNT 4340; torneamento; metal duro; cermet

    Saccharomyces cerevisiae transcriptional reprograming due to bacterial contamination during industrial scale bioethanol production

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    Abstract Background The bioethanol production system used in Brazil is based on the fermentation of sucrose from sugarcane feedstock by highly adapted strains of the yeast Saccharomyces cerevisiae. Bacterial contaminants present in the distillery environment often produce yeast-bacteria cellular co-aggregation particles that resemble yeast-yeast cell adhesion (flocculation). The formation of such particles is undesirable because it slows the fermentation kinetics and reduces the overall bioethanol yield. Results In this study, we investigated the molecular physiology of one of the main S. cerevisiae strains used in Brazilian bioethanol production, PE-2, under two contrasting conditions: typical fermentation, when most yeast cells are in suspension, and co-aggregated fermentation. The transcriptional profile of PE-2 was assessed by RNA-seq during industrial scale fed-batch fermentation. Comparative analysis between the two conditions revealed transcriptional profiles that were differentiated primarily by a deep gene repression in the co-aggregated samples. The data also indicated that Lactobacillus fermentum was likely the main bacterial species responsible for cellular co-aggregation and for the high levels of organic acids detected in the samples. Conclusions Here, we report the high-resolution gene expression profiling of strain PE-2 during industrial-scale fermentations and the transcriptional reprograming observed under co-aggregation conditions. This dataset constitutes an important resource that can provide support for further development of this key yeast biocatalyst
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