2,144 research outputs found

    First exposure to Arduino through peer-coaching: Impact on students' attitudes towards programming

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    In this paper we report the work that jeKnowledge (JĂșnior Empresa da Faculdade de CiĂȘncias e Tecnologias da Universidade de Coimbra), a student-led initiative, has done in the ‘jeKnowledge academy’ courses to actively engage Portuguese high-school students in STEM education through hands-on projects based on the low-cost Arduino platform. F2F activities, based on a peer-assisted learning strategy, were complemented with tutorials and more advanced project suggestions in a blog. Pre and post surveys on students'' attitudes towards programming and peer-coaching were administered to pre-university and first year college participants, finding an overall increase in the Likert scale for all the programming-related constructs under study (confidence, interest, gender, usefulness and professional) after the introductory course. As regards the peer-based learning approach, younger students seemed to be more eager to be taught in a less formal way than their older counterparts. The course resulted in high degrees of satisfaction for both the student tutors and their tutees

    Potencial Antibacteriano De Plantas Nativas Do Bioma Caatinga Frente A Staphylococcus Spp.: Isolados De Mastite Em Pequenos Ruminantes

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    The aim of the present study is to assess the antibacterial potential of plants from the Caatinga biome of the semi-arid region of Pernambuco, against Staphylococcus spp. isolates from cases of subclinical mastitis in small ruminants, such as goats and ewes. Ethanolic extracts of the following plants from the Caatinga biome were used: Encholirium spectabile Mart., Bromelia laciniosa Mart., Neoglaziovia variegata Mez., Amburana cearensis (Fr. Allem.) A.C.Smith, Hymenaea martiana Hayne, and Selaginella convoluta Spring. The presence of phenolic components, flavonoids, steroids, and terpenoids was verified for all the tested extracts. The mean minimal bactericide concentrations of the extracts of E. spectabile, B. laciniosa, and N. variegate were 11,379, 11,405, and 11,995 Όg/mL, respectively. The highest inhibitory activities were observed for A. cearensis and H. martiana, which inhibited 88.1 and 99.4% of the isolates, respectively. Other studies focusing on in vitro and in vivo activities should be undertaken. © 2016, Universidade Federal Rural do Semi-Arid. All Rights Reserved.29375876

    A Avaliação Institucional Participativa E Os Espaços Políticos De Participação Construídos,reinventados,conquistados Na Escola

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    This article considers the Participatory Institutional Evaluation (AIP) as an important counter-regulatory resource that expresses constructive reaction of different actors towards the achievement of social quality of public schools. The article analyzes the powers,limits and challenges faced by the existing collegiate bodies (School Council) and the alternative space proposed by the Participatory Institutional Evaluation (Self Evaluation Commission),based on the experience of the Municipal Education of Campinas/SP,as part of a research conducted at the Centre of Education-OBEDUC/CAPES. The coordination of the progressive forces of school and society,which is opposed to the advances of corporate reformers,demands the existence of qualification of social spaces characterized by critical and plural dialogue among social actors so they can think,negotiate and decide important issues in a collective way,benefiting the childrenŽs right to have a socialquality public education. © 2016,Centro de Estudos Educacao e Sociedade - CEDES. All rights reserved.369917519

    Effect Of Fixative Type And Fixation Time On The Morphology Of Equine Preantral Ovarian Follicles

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    The aim of this study was to investigate the efficacy of the tissue fixatives Bouin, Carnoy and 10% Formaldehyde in equine ovarian fragments. Ovaries (n=4) from mares of mixed breeds were obtained at a local slaughterhouse and transported at 20 oC in a thermo container. Immediately after collection, the ovaries were washed with a modified PBS solution (CultilabR, Campinas-SP, Brazil) and divided into nine fragments with approximately 5x5x1 mm, removed from the parenchyma of each ovary. The ovarian fragments were then immersed in three different fixatives, Bouin (B) Carnoy (C) or 10% Formaldehyde (F) for 6, 12 or 24 hours. Each fragment was individually immersed in a 20 mL tube containing 20 times the volume of fixative solution. After this period, the fragments were held in 70% ethanol for 24 hours. Each procedure was performed in four replicates. For histological analysis, the specimens were dehydrated in increasing concentrations of alcohol, submitted to diaphanization in xylol and embedded in paraffin. Serial sections of 5 'Êm were made with the use of a rotating microtome (LeicaR type, Wetzlar, Germany), followed by slide mounting and staining with periodic acid-Schiff (PAS) and hematoxylin. A total of 540 slides with 1,620 sections were evaluated, which contained 465 preantral follicles that were classified as normal or degenerated. Follicles were considered as degenerated when presented at least one of the following aspects: cytoplasm retraction, pyknotic nucleus, cytoplasmic vacuoles, displacement of granulosa cells and/or disruption of the basal membrane. A logistic regression test was used for statistical analysis, and differences were considered significant when P<0.05. The Carnoy fixative, when used for 24 hours, provided the best conditions of morphological integrity (53.3%; 32/60) compared to all others, and the use of Boiun for 24 hours was considered the worst treatment (19.1%; 9/47). The other treatments lead to the following results: C12h 50% (30/60), C6 H 40% (24/60), F24h 37.8% (17/45), F12h 35.1% (13/37), F6h 32% (16/50), B12h 30.5% (18/59) and B6h 24.4% (11/45). Therefore, we suggest that fixation of equine ovarian tissue with Carnoy for 24 hours is the most suitable protocol for morphological preservation of pre-antral follicles.37124325

    Multivariate analysis of the water quality variation in the Serra da Estrela (Portugal) Natural Park as a consequence of road deicing with salt.

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    The concentration of some anions (Cl, F, NO3, and SO4), cations (Na, K, Ca, and Mg), pH and conductivity was determined in seven sampling points in the Serra da Estrela Mountains (Portugal) to verify if the application of road deicing with salt provokes impact in the water quality. Multivariate chemometric data analysis techniques of clustering and factor analysis were used. Preliminary analysis shows an overall conductivity increase in late spring and a decrease in late summer. A strong association between sodium chloride and the conductivity was observed by cluster analysis. Factor analysis supports the previous results and shows that the variation of the concentration of sodium chloride is the main source of the variance of the data along the year. In conclusion, the spreading of salt during the winter creates a local and seasonal impact on the water quality

    Estado da arte na terapĂȘutica anticoagulante: Novas abordagens

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    Anticoagulant therapy was for a long time, limited to the use of heparins and warfarins. Recently, has been introduced in the market new alternative antithrombotic to this therapy. The availability of an oral of FXa or thrombin inhibitors has provided relevant clinical results in assays for the prophylaxis of postoperative venous thrombosis. However, these drugs do not have the polypharmacology of heparins. In this context, the investigation of small molecules that mimic the functions of the sulfated glycosaminoglycans, without the drawbacks characteristic of large chain heparins, has emerged as an area of research alternative. In this work, the major therapeutic approaches for the treatment of venous thrombosis are exposed, and is given a special focus to the study of our research group in the search for small molecules active dual antiplatelet and anticoagulant. Keywords: Anticoagulant therapy, Warfarins, Sulfated glycosaminoglycans A terapĂȘutica anticoagulante foi, durante muito tempo, limitada ao uso de heparinas e varfarinas. Recentemente foram introduzidas no mercado novas alternativas a esta terapĂȘutica antitrombĂłtica. A disponibilidade para uso oral quer de agentes inibidores do FXa quer da trombina tem proporcionado resultados clĂ­nicos revelantes em ensaios para a profilaxia da trombose venosa pĂłs-operatĂłria. No entanto, estes fĂĄrmacos nĂŁo apresentam a polifarmacologia Ășnica das heparinas. Neste contexto, a investigação de pequenas molĂ©culas sulfatadas que mimetizem as funçÔes dos glicosaminoglicanos, sem os inconvenientes caracterĂ­sticos das grandes cadeias de heparinas, tem surgido como uma ĂĄrea de investigação alternativa. Neste trabalho, sĂŁo expostas as principais abordagens na terapĂȘutica para o tratamento da trombose venosa e Ă© dado um enfoque especial ao estudo desenvolvido no nosso grupo de investigação na procura de pequenas molĂ©culas com atividade dual anticoagulante e antiagregante plaquetĂĄria

    The effect of pH on the simultaneous determination of Sulfamethoxazole and Trimethoprim by Ultraviolet Spectrophotometry and Multivariate Calibration

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    Analytical techniques based on Ultraviolet (UV) spectrophotometry are widely used in pharmaceutical analysis, because they are simple and inexpensive. The choice of pH is critical in the development of univariate methods for pharmaceutical quantitation by UV spectrophotometry since changes may modify the absorption spectrum profile. Similar to univariate methods by UV spectrophotometry changes in pH may influence the predictive ability of multivariate models, affecting the resultant analytical performance. We report herein on the influence of pH on the simultaneous determination of sulfamethoxazole (SMZ) and trimethoprim (TMP) in tablets using UV spectrophotometry and multivariate calibration. Data were recorded using a UV spectrophotometer in the wavelength range of 200 to 350 nm. The experimental matrix was constructed using 36 synthetic samples of SMZ-TMP mixtures. The concentration ranges used for the investigation were 14.0 to 26.0 mg L-1 for SMZ and 2.8 to 5.2 mg L-1 for TMP. The Partial Least Squares (PLS) regression models were generated with full-spectrum and multiple pH levels. At pH 4.3, lower values of relative standard error of prediction (RSEP %) for SMZ (1.83) and TMP (1.13) were obtained. The PLS model at pH 4.3 was used for the quantification of real samples (tablets obtained from 13 different manufacturers) and the results were compared with conventional procedures using high performance liquid chromatography (HPLC).

    Role of magnetic anisotropy on the magnetic properties of Ni nanoclusters embedded in a ZnO matrix

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    We have investigated the magnetic properties of Ni nanoaggregates produced by ion implantation in ZnO single crystals. Several deviations from classical models usually adopted to describe the magnetic properties of nanoparticle systems were found. The strain between host and Ni nanoaggregates induces a magnetic anisotropy with a preferred direction. We show that these anisotropy effects can be misinterpreted as a ferromagnetic or antiferromagnetic coupling among the nanoaggregates similar to that of an oriented, interacting nanocrystal ensemble

    Steroid–quinoline hybrids for disruption and reversion of protein aggregation processes

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    Reversing protein aggregation within cells may be an important tool to fight protein-misfolding disorders such as Alzheimer’s, Parkinson’s, and cardiovascular diseases. Here we report the design and synthesis of a family of steroid−quinoline hybrid compounds based on the framework combination approach. This set of hybrid compounds effectively inhibited AÎČ1−42 self-aggregation in vitro by delaying the exponential growth phase and/or reducing the quantity of fibrils in the steady state. Their disaggregation efficacy was further demonstrated against preaggregated AÎČ1−42 peptides in cellular assays upon their endocytosis by neuroblastoma cells, as they reverted both the number and the average area of fibrils back to basal levels. The antiaggregation effect of these hybrids was further tested and demonstrated in a cellular model of general protein aggregation expressing a protein aggregation fluorescent sensor. Together, our results show that the new cholesterol−quinoline hybrids possess wide and marked disaggregation capacities and are therefore promising templates for the development of new drugs to deal with conformational disorders.Thanks are due to the University of Aveiro, FCT/MEC, Centro 2020 and Portugal2020, the COMPETE Program, and the European Union (FEDER Program) via the financial support to the research units LAQV-REQUIMTE (UIDB/50006/2020), IBiMED (UID/BIM/04501/2019) and CICECO- Aveiro Institute of Materials (UID/CTM/50011/2019), financed by national funds through the FCT/MCTES, to the Portuguese NMR Network, to the ThiMES Project (POCI-01- 0145-FEDER-016630), and to the PAGE Project “Protein Aggregation Across the Lifespan” (CENTRO-01-0145- FEDER-000003), including postdoctoral grants to H.M.T.A. (BPD/UI98/4861/2017) and R.N.d.S. (BPD/UI98/6327/2018). M.P. was supported by Ph.D. Grant SFRH/BD/135655/2018. A.R.S. and S.G. were supported by national funds (OE) through FCT, I.P., in the scope of the framework contract foreseen in numbers 4, 5, and 6 of Article 23 of the Decree-Law 57/2016 of August 29, changed by Law 57/2017 of July 19. Microphotographs were acquired in the LiM facility of iBiMED/UA, a member of the Portuguese Platform of BioImaging (PPBI) (POCI-01-0145-FEDER-022122).info:eu-repo/semantics/publishedVersio

    Biosorbents in the Metallic Ions Determination

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    This chapter provides an overview and discusses analytical strategies for metallic ions determination using solid phase extraction. Solid phase extraction (SPE) is a much-used technique for extraction and/or concentration of complex samples, so that the analytes present in low concentration were detected mainly using chromatographic methods. However, in recent years, this technique has been widely used in the development of methodologies for metallic ions determination in the deferential samples. This technique shows simplicity and rapidity comparing with other conventional techniques, liquid–liquid extraction, cloud point extraction and others. Solid phase extraction procedures become even more interesting when commercial adsorbents are exchanged for others with higher adsorptive capacity, selectivity, flexibility, economy and low environmental impacts. For this purpose, some inorganic, organic and several natural adsorbents are used. New approaches to obtain adsorbent materials from natural sources such as fungi, bacteria, industrial residues and composting materials have received attention. These materials have been used in the development of analytical methods with varied proposals, such as preconcentration or speciation of metal ions
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