3,124 research outputs found

    Different Uses for Remote Labs in Electrical Engineering Education: Initial Conclusions of an Ongoing Experience

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    Laboratories are a fundamental part of engineering education due to the very nature of the engineering profession. This is a characteristic of all en-gineering courses, though it may vary from one curriculum to the other and even in the same curriculum. This paper is dedicated to the analysis of different applications of a remote lab in an Electrical Engineering curriculum. If the types of experiments it offers are concerned, it is classified as an Electric and Electronic Circuits lab; one in a set that also has Digital Electronics, Analog Electronics, Electrical Machines, Control Systems, etc. But it is not a traditional lab – it is a remote lab, with traditional components remotely accessed over the Internet. This work presents the preliminary results of the deployment of VISIR – a remote lab for Electric and Electronic Circuits in some courses. It discusses the different course contexts and how the use of VISIR was adapted to each one. Results of students’ opinions are presented and discussed.N/

    Poly(Ethylene glycol) diacrylate iongel membranes reinforced with nanoclays for co2 separation

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    Despite the fact that iongels are very attractive materials for gas separation membranes, they often show mechanical stability issues mainly due to the high ionic liquid (IL) content (≥60 wt%) needed to achieve high gas separation performances. This work investigates a strategy to improve the mechanical properties of iongel membranes, which consists in the incorporation of montmorillonite (MMT) nanoclay, from 0.2 to 7.5 wt%, into a cross-linked poly(ethylene glycol) diacrylate (PEGDA) network containing 60 wt% of the IL 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([C2mim][TFSI]). The iongels were prepared by a simple one-pot method using ultraviolet (UV) initiated polymerization of poly(ethylene glycol) diacrylate (PEGDA) and characterized by several techniques to assess their physico-chemical properties. The thermal stability of the iongels was influenced by the addition of higher MMT contents (>5 wt%). It was possible to improve both puncture strength and elongation at break with MMT contents up to 1 wt%. Furthermore, the highest ideal gas selectivities were achieved for iongels containing 0.5 wt% MMT, while the highest CO2 permeability was observed at 7.5 wt% MMT content, due to an increase in diffusivity. Remarkably, this strategy allowed for the preparation and gas permeation of self-standing iongel containing 80 wt% IL, which had not been possible up until now.publishersversionpublishe

    Exploring Metabolic Signatures of Ex Vivo Tumor Tissue Cultures for Prediction of Chemosensitivity in Ovarian Cancer

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    Predicting patient response to treatment and the onset of chemoresistance are still major challenges in oncology. Chemoresistance is deeply influenced by the complex cellular interactions occurring within the tumor microenvironment (TME), including metabolic crosstalk. We have previously shown that ex vivo tumor tissue cultures derived from ovarian carcinoma (OvC) resections retain the TME components for at least four weeks of culture and implemented assays for assessment of drug response. Here, we explored ex vivo patient-derived tumor tissue cultures to uncover metabolic signatures of chemosensitivity and/or resistance. Tissue cultures derived from nine OvC cases were challenged with carboplatin and paclitaxel, the standard-of-care chemotherapeutics, and the metabolic footprints were characterized by LC-MS. Partial least-squares discriminant analysis (PLS-DA) revealed metabolic signatures that discriminated high-responder from low-responder tissue cultures to ex vivo drug exposure. As a proof-of-concept, a set of potential metabolic biomarkers of drug response was identified based on the receiver operating characteristics (ROC) curve, comprising amino acids, fatty acids, pyrimidine, glutathione, and TCA cycle pathways. Overall, this work establishes an analytical and computational platform to explore metabolic features of the TME associated with response to treatment, which can leverage the discovery of biomarkers of drug response and resistance in OvC.publishersversionpublishe

    Parents’ Perceptions of Student Academic Motivation During the COVID-19 Lockdown: A Cross-Country Comparison

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    The COVID-19 outbreak has ravaged all societal domains, including education. Home confinement, school closures, and distance learning impacted students, teachers, and parents’ lives worldwide. In this study, we aimed to examine the impact of COVID-19-related restrictions on Italian and Portuguese students’ academic motivation as well as investigate the possible buffering role of extracurricular activities. Following a retrospective pretest–posttest design, 567 parents (nItaly = 173, nPortugal = 394) reported on their children’s academic motivation and participation in extracurricular activities (grades 1 to 9).info:eu-repo/semantics/publishedVersio

    Poly(ionic liquid)-based engineered mixed matrix membranes for CO2/H2 separation

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    Unformatted preprintPoly(ionic liquid)s (PIL) have emerged as a class of versatile polyelectrolites, that can be used to prepare new materials able to achieve superior performances compared to conventional polymers. The combination of PILs with ionic liquids (ILs) may serve as a suitable matrix for the preparation of membranes for gas separation. In this work, mixed matrix membranes (MMMs) combining a pyrrolidinium-based PIL, an IL and three highly CO2-selective metal organic frameworks (MOFs) were prepared. The different MOFs (MIL-53, Cu3(BTC)2 and ZIF-8) were used as fillers, aiming to maximize the membranes performance towards the purification of syngas. The influence of different MOFs and loadings (0, 10, 20 and 30 wt.%) on the thermal and mechanical stabilities of the membranes and their performance in terms of CO2 permeability and CO2/H2 ideal selectivity was assessed. The compatibility between the materials was confirmed by SEM-EDS and FTIR spectroscopy. The prepared MMMs revealed to be thermally stable within the temperature range of the syngas stream, with a loss of mechanical stability upon the MOF incorporation. The increasing MOF content in the MMMs, resulted in an improvement of both CO2 permeability and CO2/H2 ideal selectivity. Among the three MOFs studied, membranes based on ZIF-8 showed the highest permeabilities (up to 97.2 barrer), while membranes based on MIL-53 showed the highest improvement in selectivity (up to 13.3). Remarkably, all permeation results surpass the upper bound limit for the CO2/H2 separation, showing the membranes potential for the desired gas separation.This work was partially supported by R&D Units UID/Multi/04551/2013 (Green-it), UID/QUI/00100/2013 (CQE), and the Associated Laboratory Research Unit for Green Chemistry, Technologies and Clean Processes, LAQV which is financed by national funds from FCT/MCTES(UID/QUI/50006/2013) and co-financed by the ERDF under the PT2020 Partnership Agreement (POCI-01-0145-FEDER-007265). Ana R. Nabais, Luísa A. Neves and Liliana C. Tomé acknowledge FCT/MCTES for financial support through project PTDC/CTM-POL/2676/2014, FCT Investigator Contract IF/00505/2014 and Post-doctoral research grant SFRH/BDP/101793/2014, respectively. This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No 745734

    Erratum: Moreira, J., et al., Spin-Coated Polysaccharide-Based Multilayered Freestanding Films with Adhesive and Bioactive Moieties. Molecules 2020, 25, 840

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    Erratum: Moreira, J., et al., Spin-Coated Polysaccharide-Based Multilayered Freestanding Films with Adhesive and Bioactive Moieties. Molecules 2020, 25, 840. DOI: 10.3390/molecules25040840The authors wish to make changes to the published paper 11 j. 1. UV-Vis Analysis of Catechol-Modified Polymers In the original manuscript theie is a mistake concerning the word "Wavenumber" in the X-Coordinate in Figure 1. Tile corrected word is "Wavelength". Tlx- A uthors also wish to change mg«mL-l to mg ml-1 in the legend of Figure l;see corrected Figure 1 below. (Figure Presented).(undefined

    Pseudotyping retrovirus like particles vaccine candidates with Hepatitis C virus envelope protein E2 requires the cellular expression of CD81

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    Hepatitis C virus (HCV) infects 3% of world population being responsible for nearly half a million deaths annually urging the need for a prophylactic vaccine. Retrovirus like particles are commonly used scaffolds for antigens presentation being the core of diverse vaccine candidates. The immunogenicity of host proteins naturally incorporated in retrovirus was hypothesized to impact the performance of retrovirus based vaccines. In this work, the capacity of engineered retrovirus like particles devoided of host protein CD81 to display HCV envelope antigens was compared to non-engineered particles. A persistent inability of CD81 negative VLPs to incorporate HCV E2 protein as a result from the inefficient transport of HCV E2 to the plasma membrane, was observed. This work enabled the identification of a CD81-mediated transport of HCV E2 while stressing the importance of host proteins for the development of recombinant vaccines.publishe

    Characterisation of Films Based on Exopolysaccharides from Alteromonas Strains Isolated from French Polynesia Marine Environments

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    LA/P/0140/202019 UID/AGR/04129/2020 LA/P/0037/2020This work assessed the film-forming capacity of exopolysaccharides (EPS) produced by six Alteromonas strains recently isolated from different marine environments in French Polynesia atolls. The films were transparent and resulted in small colour alterations when applied over a coloured surface (ΔEab below 12.6 in the five different colours tested). Moreover, scanning electron microscopy showed that the EPS films were dense and compact, with a smooth surface. High water vapour permeabilities were observed (2.7–6.1 × 10−11 mol m−1 s−1 Pa−1), which are characteristic of hydrophilic polysaccharide films. The films were also characterised in terms of barrier properties to oxygen and carbon dioxide. Interestingly, different behaviours in terms of their mechanical properties under tensile tests were observed: three of the EPS films were ductile with high elongation at break (ε) (35.6–47.0%), low tensile strength at break (Ꞇ) (4.55–11.7 MPa) and low Young’s modulus (εm) (10–93 MPa), whereas the other three were stiffer and more resistant with a higher Ꞇ (16.6–23.6 MPa), lower ε (2.80–5.58%), and higher εm (597–1100 MPa). These properties demonstrate the potential of Alteromonas sp. EPS films to be applied in different areas such as biomedicine, pharmaceuticals, or food packaging.publishersversionpublishe
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