Uma abordagem prática do experimento de Oersted em sala de aula

As escolas de ensino médio brasileiras enfrentam o grande desafio de despertar o interesse dos alunos na busca pelo conhecimento. Particularmente, ao se trabalhar com o ensino de Física, nota-se grande dificuldade e desinteresse por parte dos alunos. Segundo vários autores (SOUSA, 2010; MARTINS, 2014), um dos principais motivos seriam as aulas monótonas, cheias de cálculos, e sem conexões da teoria com a prática. Em função dessas dificuldades, tem-se buscado “aulas mais dinâmicas na tentativa de fazer do aluno um agente no processo de ensino-aprendizagem” (GUEDES, 2017), atribuindo ao docente a responsabilidade de disponibilizar conteúdos e/ou abordagens que despertem nos alunos o interesse pelo estudo/aprendizado e oriente-os rumo a uma nova maneira de construção do conhecimento. Neste sentido, propõe-se neste trabalho a abordagem de um tema através da construção e análise de experimentos, uma vez que, de acordo com o relatado por outros autores (MARTINS, 2014; MORAES; JÚNIOR, 2014; QUINTAL; SANTOS; GASPAR, 2005; FILHO; CALUZI, 2009), a realização de experimentos durante as aulas permite uma maior interação entre professor e alunos, e destes últimos com os conceitos estudados, além de ser uma forma mais atraente de prender a atenção dos mesmos, contribuindo de maneira importante para o aprendizado. Assim, decidiu-se pela construção de um experimento de baixo custo para se trabalhar conteúdos históricos e conceituais de eletromagnetismo. Foi escolhida a experiência de Oersted, que teve papel fundamental no desenvolvimento do eletromagnetismo. Indo além de uma simples demonstração, o experimento desenvolvido possibilita ao aluno verificar que o módulo do campo magnético produzido por um fio retilíneo infinito decresce com o inverso da distância

trans-5,6-Diphenyl­perhydro­pyran-2,4-dione

In the title compound, C17H14O3, the pyran ring adopts a boat conformation and the dihedral angle between the aromatic ring planes is 59.1 (1)°. In the crystal structure inter­molecular C—H⋯O hydrogen bonds and C—H⋯π inter­actions link the mol­ecules

Cell-cycle and suppressor proteins expression in uterine cervix in HIV/HPV co-infection: comparative study by tissue micro-array (TMA)

<p>Abstract</p> <p>Background</p> <p>The oncoproteins of human papillomavirus (HPVs) directly effect cell-cycle control. We hypothesize that regulatory and cell cycle protein expression might be additionally modified in the cervix of HIV/HPV co-infected women.</p> <p>Methods</p> <p>We analyzed the expression of Rb, p27, VEGF and Elf-1 transcriptor factor by immunohistochemistry in 163 paraffin-embeded cervical samples using Tissue Micro-Array (TMA) and correlated this to HIV-1 and HPV infection.</p> <p>Results</p> <p>HIV/HPV co-infection was associated with a significant increase in expression (p < 0.001) of VEGF and p27 in both low and high grade CIN when compared to the cervices of women infected by HPV alone. Decreased Rb expression was evident with increased CIN grade in the cervices of women infected with HPV alone (p = 0.003 average of cells/mm²in CIN I: 17.9, CIN II/III: 4.8, and tumor 3.9). Rb expression increased 3-fold for both low and high grade CIN with HPV/HIV-1 co-infection compared to HPV infection alone but did not reach statistical significance. There was a significant increase in Elf-1 expression in HPV+/HIV- women with CIN II/III and tumor (average of cells/mm²in CIN I: 63.8; CIN II/III: 115.7 and tumor: 112.0, p = 0.005), in comparison to controls.</p> <p>Conclusion</p> <p>Co-infection of HPV and HIV leads to significant increase in the VEGF and p27 expression when compared to HPV+/HIV-negative infection that could facilitate viral persistence and invasive tumor development.</p

Electroanalysis of Imidacloprid Insecticide in River Waters Using Functionalized Multi-Walled Carbon Nanotubes Modified Glassy Carbon Electrode

In this work, a functionalized multi-walled carbon nanotubes modified glassy carbon electrode (GCE/MWCNT-f) was optimized for the direct determination of imidacloprid (IMC) insecticide in river water. The functionalized material was characterized by infrared spectroscopy with Fourier transform (FTIR) and the modified electrode by scanning electron microscopy (SEM) and cyclic voltammetry (CV). Results revealed that the GCE/MWCNT-f effectively increased the response toward IMC reduction by enhancing the reduction peak current and decreasing the peak potential in comparison with the bare electrode. After optimizing the electroanalytical conditions, the GCE/MWCNT-f showed a linear voltammetric response at concentration ranging from 2.40 × 10−7 to 3.50 × 10−6 mol L−1, with detection and quantification limits of 4.15 × 10−7 mol L−1 and 1.38 × 10−6 mol L−1, respectively. The recovery rate of IMC in spiked river water samples varied from 90–95%. Thus, this sensor can be a promising tool for the analysis and monitoring of IMC in complex environmental matrices.info:eu-repo/semantics/publishedVersio

Ins and outs of the cultural polis: informality, culture and governance in the global South

This paper provides an epistemological critique of informality by focusing on cultural governance in two cities of the global South, Rio de Janeiro, Brazil, and Dakar, Senegal. Aiming to enrich debates about urban creativity and urban cultural policy, which are still mainly focused on and articulated from the global North, we consider the broad field of ‘informality’ research as an entry point for such a discussion. Using case studies from African and Latin American contexts, we focus on the interstices of cultural policy and the borderlands of (in)formality, examining how governmental institutions are entangled in informal processes, and how grassroots cultural interventions become part of mainstream cultural circuits. The analysis sheds light on how these creative spaces of cultural production, located in Southern contexts of urban extremes, contribute to the vitality of informal urbanisms and unsettle predominant views that see them merely as sites ofinfrastructural poverty and social exclusion. The paper suggests that a creative remapping of informality, through an inquiry of the ‘ins’ and ‘outs’ of the cultural polis, could improve our translating capacity of academic discourse into institutional/policy-related operations

Protection against tuberculosis by a single intranasal administration of DNA-hsp65 vaccine complexed with cationic liposomes

<p>Abstract</p> <p>Background</p> <p>The greatest challenges in vaccine development include optimization of DNA vaccines for use in humans, creation of effective single-dose vaccines, development of delivery systems that do not involve live viruses, and the identification of effective new adjuvants. Herein, we describe a novel, simple technique for efficiently vaccinating mice against tuberculosis (TB). Our technique consists of a single-dose, genetic vaccine formulation of DNA-hsp65 complexed with cationic liposomes and administered intranasally.</p> <p>Results</p> <p>We developed a novel and non-toxic formulation of cationic liposomes, in which the DNA-hsp65 vaccine was entrapped (ENTR-hsp65) or complexed (COMP-hsp65), and used to immunize mice by intramuscular or intranasal routes. Although both liposome formulations induced a typical Th1 pattern of immune response, the intramuscular route of delivery did not reduce the number of bacilli. However, a single intranasal immunization with COMP-hsp65, carrying as few as 25 μg of plasmid DNA, leads to a remarkable reduction of the amount of bacilli in lungs. These effects were accompanied by increasing levels of IFN-γ and lung parenchyma preservation, results similar to those found in mice vaccinated intramuscularly four times with naked DNA-hsp65 (total of 400 μg).</p> <p>Conclusion</p> <p>Our objective was to overcome the significant obstacles currently facing DNA vaccine development. Our results in the mouse TB model showed that a single intranasal dose of COMP-hsp65 elicited a cellular immune response that was as strong as that induced by four intramuscular doses of naked-DNA. This formulation allowed a 16-fold reduction in the amount of DNA administered. Moreover, we demonstrated that this vaccine is safe, biocompatible, stable, and easily manufactured at a low cost. We believe that this strategy can be applied to human vaccines to TB in a single dose or in prime-boost protocols, leading to a tremendous impact on the control of this infectious disease.</p