The effect of curricular activities on learner autonomy: the perspective of undergraduate mechanical engineering students

This study researches how first-year engineering students perceived the influence of curricular activities on their own learning autonomy, measured with an adaptation of the Personal Responsibility Orientation to Self-direction in Learning Scale (PRO-SDLS). Participants were questioned to assess the influence of the teacher’s role. The results indicate that learners’ characteristics (motivation and self-efficacy) contribute more to learner autonomy (LA) than the teaching–learning transaction (control and initiative), as in the original PRO-SDLS validation. The most autonomous learners presented higher values in all LA components and dimensions, but the differences were greater in motivation and initiative. The participants with higher LA were not as dependent on the teacher, regarding assessment, the completion of classroom tasks and deadlines. Regardless of the degree of autonomy in learning, all participants viewed teachers as the main source of information. Therefore, LA plays an important role in teaching activities planning. Suggestions for adjustments and more flexible learning scenarios are formulated.info:eu-repo/semantics/publishedVersio

Wide-band-gap InAlAs solar cell for an alternative multijunction approach

We have fabricated an In_(0.52)Al_(0.48)As solar cell lattice-matched to InP with efficiency higher than 14% and maximum external quantum efficiency equal to 81%. High quality, dislocation-free In_xAl_(1−x)As alloyed layers were used to fabricate the single junction solar cell. Photoluminescence of In_xAl_(1−x)As showed good material quality and lifetime of over 200 ps. A high band gap In_(0.35)Al_(0.65)As window was used to increase light absorption within the p-n absorber layer and improve cell efficiency, despite strain. The InAlAs top cell reported here is a key building block for an InP-based three junction high efficiency solar cell consisting of InAlAs/InGaAsP/InGaAs lattice-matched to the substrate

Towards an optimized all lattice-matched InAlAs/InGaAsP/InGaAs multijunction solar cell with efficiency >50%

An approach for an all lattice-matched multijunction solar cell optimized design is presented with 5.807 Å lattice constant, together with a detailed analysis of its performance by means of full device modeling. The simulations show that a (1.93 eV)In_(0.37)Al_(0.63)As/(1.39 eV)In_(0.38)Ga_(0.62)As_(0.57)P_(0.43)/(0.94 eV)In_(0.38)Ga_(0.62)As 3-junction solar cell can achieve efficiencies >51% under 100-suns illumination (with V_(oc) = 3.34 V). As a key proof of concept, an equivalent 3-junction solar cell lattice-matched to InP was fabricated and tested. The independently connected single junction solar cells were also tested in a spectrum splitting configuration, showing similar performance to a monolithic tandem device, with V_(oc) = 1.8 V

Dual action of chronic ethanol treatment on LPS-induced response in C6 glioma cells

AbstractIn this study we investigated the anti-inflammatory effects of chronic ethanol (EtOH) treatment on lipopolysaccharide (LPS)-stimulated C6 glioma cells. The cells were chronically treated with 200mM EtOH; coincubation with LPS and EtOH was obtained upon addition of 2μg/ml LPS to the incubation medium in the last 24h of EtOH exposure. We found that EtOH prevented the LPS-induced production of tumor necrosis factor α (TNFα) without decreasing cell viability. Either LPS treated or EtOH plus LPS treated cells presented upregulated glial fibrillary acidic protein (GFAP) and downregulated vimentin levels characterizing a program of reactive astrogliosis. Also, EtOH plus LPS stimulation greatly increased the oxidative stress generation evaluated by DCF-DA measurement, while either EtOH alone or LPS alone was unable to induce oxidative stress. Western blot analysis indicated that either EtOH, LPS or EtOH plus LPS treatments are unable to affect Akt/GSK3β signaling pathway. However, LPS alone and EtOH plus LPS co-treatment inhibited Erk phosphorylation. A dramatic loss of stress fibers was found in EtOH exposed cells, evaluated by cytochemistry using phalloidin-fluorescein. However, LPS alone was not able to disrupt actin organization. Furthermore, cells co-incubated with LPS and EtOH presented reversion of the disrupted stress fibers provoked by EtOH. Supporting this action, RhoA and vinculin immunocontent were upregulated in response to EtOH plus LPS. Interestingly, EtOH suppresses the inflammatory cascade (TNFα production) in response to LPS. Concomitantly it sustains Erk inhibition, increases oxidative stress generation and induces reactive astrogliosis in the presence of LPS, conditions associated with neurotoxicity. The effects observed were not supported by actin reorganization. Altogether, these findings suggest that Erk signaling inhibition could play a role in both suppressing TNFα production and inducing oxidative stress generation and astrogliosis, therefore modulating a dual action of EtOH plus LPS in glial cells

Whole-genome analysis of Leptospira interrogans to identify potential vaccine candidates against leptospirosis

Leptospirosis is an important global human and veterinary health problem. Humans can be infected by exposure to chronically infected animals and their environment. An important focus of the current leptospiral research is the identification of outer membrane proteins (OMPs). Due to their location, leptospiral OMPs are likely to be relevant in host-pathogen interactions, hence their potential ability to stimulate heterologous immunity. The existing whole-genome sequence of Leptospira interrogans serovar Copenhageni offers a unique opportunity to search for cell surface proteins. Predicted genes encoding potential surface proteins were amplified from genomic DNA by PCR methodology and cloned into an Escherichia coli expression system. The partially purified recombinant proteins were probed by Western blotting with sera from human patients diagnosed with leptospirosis. Sixteen proteins, out of a hundred tested, were recognized by antibodies present in human sera. Four of these proteins were conserved among eight serovars of L. interrogans and absent in the non-pathogenic Leptospira biflexa. These proteins might be useful for the diagnosis of the disease as well as potential vaccine candidates.Facultad de Ciencias ExactasInstituto de Biotecnologia y Biologia Molecula

Whole-genome analysis of Leptospira interrogans to identify potential vaccine candidates against leptospirosis

Leptospirosis is an important global human and veterinary health problem. Humans can be infected by exposure to chronically infected animals and their environment. An important focus of the current leptospiral research is the identification of outer membrane proteins (OMPs). Due to their location, leptospiral OMPs are likely to be relevant in host-pathogen interactions, hence their potential ability to stimulate heterologous immunity. The existing whole-genome sequence of Leptospira interrogans serovar Copenhageni offers a unique opportunity to search for cell surface proteins. Predicted genes encoding potential surface proteins were amplified from genomic DNA by PCR methodology and cloned into an Escherichia coli expression system. The partially purified recombinant proteins were probed by Western blotting with sera from human patients diagnosed with leptospirosis. Sixteen proteins, out of a hundred tested, were recognized by antibodies present in human sera. Four of these proteins were conserved among eight serovars of L. interrogans and absent in the non-pathogenic Leptospira biflexa. These proteins might be useful for the diagnosis of the disease as well as potential vaccine candidates.Facultad de Ciencias ExactasInstituto de Biotecnologia y Biologia Molecula

Lipopolysaccharide modulates astrocytic S100B secretion: a study in cerebrospinal fluid and astrocyte cultures from rats

<p>Abstract</p> <p>Background</p> <p>Inflammatory responses in brain are primarily mediated by microglia, but growing evidence suggests a crucial importance of astrocytes. S100B, a calcium-binding protein secreted by astrocytes, has properties of a neurotrophic or an inflammatory cytokine. However, it is not known whether primary signals occurring during induction of an inflammatory response (e.g. lipopolysaccharide, LPS) directly modulate S100B.</p> <p>Methods</p> <p>In this work, we evaluated whether S100B levels in cerebrospinal fluid (CSF) and serum of Wistar rats are affected by LPS administered by intraperitoneal (IP) or intracerebroventricular (ICV) injection, as well as whether primary astrocyte cultures respond directly to lipopolysaccharide.</p> <p>Results</p> <p>Our data suggest that S100B secretion in brain tissue is stimulated rapidly and persistently (for at least 24 h) by ICV LPS administration. This increase in CSF S100B was transient when LPS was IP administered. In contrast to these S100B results, we observed an increase in in TNFα levels in serum, but not in CSF, after IP administration of LPS. In isolated astrocytes and in acute hippocampal slices, we observed a direct stimulation of S100B secretion by LPS at a concentration of 10 μg/mL. An involvement of TLR4 was confirmed by use of specific inhibitors. However, lower levels of LPS in astrocyte cultures were able to induce a decrease in S100B secretion after 24 h, without significant change in intracellular content of S100B. In addition, after 24 h exposure to LPS, we observed a decrease in astrocytic glutathione and an increase in astrocytic glial fibrillary acidic protein.</p> <p>Conclusions</p> <p>Together, these data contribute to the understanding of the effects of LPS on astrocytes, particularly on S100B secretion, and help us to interpret cerebrospinal fluid and serum changes for this protein in neuroinflammatory diseases. Moreover, non-brain S100B-expressing tissues may be differentially regulated, since LPS administration did not lead to increased serum levels of S100B.</p

Enabling precision medicine in neonatology, an integrated repository for preterm birth research.

Preterm birth, or the delivery of an infant prior to 37 weeks of gestation, is a significant cause of infant morbidity and mortality. In the last decade, the advent and continued development of molecular profiling technologies has enabled researchers to generate vast amount of 'omics' data, which together with integrative computational approaches, can help refine the current knowledge about disease mechanisms, diagnostics, and therapeutics. Here we describe the March of Dimes' Database for Preterm Birth Research (http://www.immport.org/resources/mod), a unique resource that contains a variety of 'omics' datasets related to preterm birth. The database is open publicly, and as of January 2018, links 13 molecular studies with data across tens of thousands of patients from 6 measurement modalities. The data in the repository are highly diverse and include genomic, transcriptomic, immunological, and microbiome data. Relevant datasets are augmented with additional molecular characterizations of almost 25,000 biological samples from public databases. We believe our data-sharing efforts will lead to enhanced research collaborations and coordination accelerating the overall pace of discovery in preterm birth research

O desenvolvimento dos "Diagnosis Related Groups"- DRGs. Metodologia de classificação de pacientes hospitalares

The history of Diagnosis Related Groups (DRG's), a system for classifying patients in acute care hospitals, developed by researchers at Yale University, USA, is reviewed. DRGs are an instrument for measuring the hospital product, primarily from a management viewpoint. Starting with a review of the definitions of hospital product, the article follows the course from the first DRGs through the most recent revision, providing a summary of potential and current applications of the system in several countries, which range from payment mechanism to uses in quality control.É descrito o processo de desenvolvimento do sistema de classificação de pacientes internados em hospitais que atendem casos agudos, denominada Diagnosis Relatd Group - DRGs, desenvolvido e difundido por pesquisadores da Universidade de Yale, USA. Esse sistema vem a ser um instrumento que permite a mensuração do produto hospitalar, principalmente sob o ponto de vista gerencial. São apresentadas considerações acerca do que é entendido como produto hospitalar, seguindo nos meandros do desenvolvimento dos primeiros DRGs, até a mais recente revisão do sistema. É descrita sua utilização em alguns países e diversos usos potenciais desse sistema, que abrangem desde o uso para pagamento a instrumento de controle de qualidade

Determinação de paracetamol pela inibição da reação quimiluminescente do luminol-hipoclorito de sódio em um sistema de análise em fluxo empregando o conceito de multicomutação

A flow injection chemiluminescence method for the determination of paracetamol in pharmaceutical formulations is described. It is based on the consumption of the sodium hypochlorite by paracetamol and decreases of the analytical signal. The analytical curve was linear in the paracetamol concentration range from 5.0 x 10-6 to 5.0 x 10-5 mol L-1, with a detection limit of 1.8 x 10-6 mol L-1. The RSDs were 2.0 and 1.2% respectively for 2.0 x 10-5 and 4.0 x 10-5 mol L-1 paracetamol solutions (n = 10) and a sampling frequency of 180 h-1 was obtained