1000 resultados para MODULADORES DE LUZ
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Photodynamic Therapy (PDT) is a technique used to treat several types of lesions, such as cancer, microbial control, and esthetic dentistry cases. The performance of PDT involves the use of a photosensitizer (PS), which mainly will be located in cancer cells and is irradiated with visible light. This process, when it occurs in the presence of oxygen triggers the formation of reactive oxygen species that are cytotoxic to cells. These species cause cell death and subsequent tumor necrosis. The use of white light as a light source for multispectral Photodynamic Therapy and its consequences to the photodynamic effect is not yet completely established, and therefore there is interest in studying the parameters involved for analyzing the best conditions for applying treatment. The wavelength is crucial to improve the therapeutic effect, since both the optical properties of the biological tissue as the PS depend on these parameters. For FS studied in this work (Photogem®) are most often used wavelengths in the red region, due to their larger penetration depth in biological tissue. Thus, the light source becomes a fundamental aspect, their choice depends on the specific application and is based on the tumor location, light dose to be delivered and FS chosen. Despite all the advantages presented by lasers, the fact of having an emission spectrum essentially monochrome makes only one possible transition possible for the absorption of FS is used. Therefore, more extensive light sources such as light emitting diodes (LED), could be better used in some cases the laser, with the additional advantage of a reduced cost. Therefore, the choice of the white LED comes from an emission spectrum that still wider LED colors defined by allowing greater use of the several absorption bands and with varying depths of operation, according to the wavelength... (Complete abstract click electronic access below)
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Stem cells are defined as cells capable of self-renewal and differentiation into specialized cells when submited to external signalings in the enviroment. Among adult stem cells, mesenchymal cells occupy an important position because they can differentiate into mesodermal cells such as osteoblasts, adipocytes and chondrocytes. Cell therapy consists in the use of mesenchymal stem cells (MSC) in the treatment of degenerative diseases and harmed tissue reconstruction. Due to the longstanding and costly procedure for cultivation of MSC, it was proposed the use of low power light sources, such as light emitting diodes (LED), to optimize these factors. Recent works have shown a series of results from the influence of LED light on biological tissues such as increased rate of cell proliferation, increased RNA, DNA and ATP synthesis rate. The purpose of this study is to compare the biomodulator effect of LED light set at wavelengths 630nm ± 10nm and 805nm ± 10nm on the mesenchymal stem cells proliferation. For this, the mesenchymal stem cells culture adopted the procedure used in the Departament of Animal Reproduction and Veterinary Radiology of the Faculty of Veterinary Medicine and Animal Sciences of Botucatu. MSC were obtained from an adult horse bone marrow, and isolated by density gradient separation, with the FICOLL reagent and by centrifugation. The pellet containing the stem cells was removed and these were placed in low glucose DMEM culture medium, containing 10% fetal calf serum and antibiotics. The material was observed daily by inverted microscopy for monitoring the progression of the cells and subsequently the amount of cells were counted in a Neubauer counting chamber. The amount of MSC was obtained by cell culture seeded in 24 wells culture plate and segregated into three distinct groups: Group 1 was irradiated with wavelength set at 630nm ± 10 nm, Group... (Complete abstract click electronic access below)
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Neste artigo, apresentaremos um estudo da tradução da obra Inferno da autora Patrícia Melo, com o título Inferno, por Clifford Landers. Buscamos refletir sobre como são projetados no exterior uma visão da realidade violenta de grandes centros urbanos brasileiros e sobre o quanto o tradutor conseguiu resgatar da nossa sociedade no texto traduzido. Partimos do pressuposto de que o tradutor, consciente ou inconscientemente, usa recursos durante o processo de mediação entre o texto de partida e o texto de chegada, que tornam a leitura da obra traduzida mais fácil. Baker (1996) propõe a investigação de tipos de comportamento linguístico característicos de textos traduzidos. O objetivo desse trabalho é identificar aspectos de normalização presentes na tradução. Para a investigação, recorremos aos Estudos da Tradução Baseados em Corpus (Baker, 1993, 1996; Camargo, 2005, 2007), à Linguística de Corpus (Berber Sardinha, 2004) e aos estudos sobre normalização de Scott (1998). Pode-se observar a ocorrência de mudança de registro de linguagem, omissões, adições, diferenças no comprimento das sentenças e relacionadas a imprecisões de expressões. Espera-se que o presente trabalho possa contribuir para uma maior conscientização das tendências apresentadas pelos tradutores, e para apresentar as possibilidades oferecidas pela intersecção dos Estudos da Tradução Baseados em Corpus e da Linguística de Corpus.
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In the current context of lexicographical studies, there have been increasing discussions concerning the issue of the relationship between theoretical knowledge of the lexicon and pedagogical practices involved in its teaching. However, in this context, the special lexicon of Portuguese such as neologisms, foreign words, slang and idioms has received little attention from researchers. There are many theoretical studies on each one of these phenomena, but few studies aim at an organization and inclusion of special units in the teaching of Portuguese. For this reason, this article presents a reflection on the teaching of idioms, and, despite the widely held belief that dictionaries are only needed for the teaching of foreign languages, the article suggests the implementation of special dictionaries for the teaching of Portuguese Language in elementary education.
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This paper is result of an analysis of the Brave New World by Aldous Huxley, made based on the perspective of discursive semiotics. For both, the elements of the generative course of meaning were applied, particularly those in works of Barros (2001) and Fiorin (2000). In view of that each of the three levels (elementary, narrative and discourse) of semiotics approach are considered capable of independent descriptions, we sought through the (re) construction of meaning of specific parts of the work and also the relationship of its thematic route with the time it was composed, found that, as a result of this work, the relationships between fiction and reality and thus the relevance of the work of Aldous Huxley
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Pós-graduação em Educação - FFC
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Pós-graduação em Filosofia - FFC
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Action-research conducted in a a Brazilian public elementary school. Using the tools provided by Meirieu, the point was to offer teachers the possibility of improving their perception of their own knowledge and practice. The process consisted in filming classes and watching the films together for reflexive interaction. When given the chance to look at themselves, their practice and their students, the teachers started to do build a new perspective of the learning process and to deconstruct certain truths regarding their interventions, which brought in new outlooks, new discourse and new practices.
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Este trabalho pretende investigar a eficiência do Programa “Luz para Todos” - LPT, na alocação de recursos financeiros para os estados mais carentes da nação. Para tanto, utiliza-se o ferramental da Análise Exploratória de Dados Espaciais (AEDE). Inicialmente, elabora-se uma análise univariada para o PIB estadual per capita, verificando-se dois clusters significativos para essa variável: um, com valores elevados e outro, com valores reduzidos. Em seguida, utiliza-se a mesma metodologia para avaliar os recursos alocados pelo Programa LPT, detectando-se os estados com valores significativos para essa variável. Por fim, é realizada uma análise bivariada confrontando a renda per capita estadual contra os recursos alocados pelo Programa LPT em cada estado. Os resultados sugerem que o Programa LPT cumpre parcialmente sua função social, pois dois estados “ricos”, Minas Gerais e Goiás, possuem como vizinhos, estados que receberam quantias abaixo da média do referido Programa.
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This study evaluated in vitro the shear bond strength of brackets bonded with xenon plasma arc light, light-emitting diode (LED) and conventional halogen light using different curing times. Brackets were bonded to the buccal surface of 60 human maxillary premolars allocated to five groups. In groups 1 and 2, the resin was cured with the plasma arc for three and six seconds (s), respectively; in groups 3 and 4, the LED was used for five and ten s, respectively; and in group 5, the halogen light was used for 40 s. The specimens were stored in water for 24 hours and subjected to a shear force until bracket failure. The debonding pattern was classified according to the adhesive remnant index (ARI). The results were assessed by Anova and the SNK post-hoc test. No differences were detected among groups 2, 4 and 5, which showed higher averages than groups 1 and 3, which were not different between themselves. The ARI scores showed no differences among the three types of light sources in all times tested. Plasma arc and LED lights can be used with shorter curing times, within certain limits, than conventional halogen light for bonding orthodontic brackets, without decreasing bond strength.
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Nanotechnology, the science of minuscule, has developed products which are able t o manipulate atoms and molecules that could be applied in the sterilization process of dental instruments. Objetives: The objective of the present study was to evaluate the self-cleaning action of TiO2 and Ag nanoparticles coating on dental instruments by the photocataliys process under UV and visible light irradiation. Material and method: Microbiologic tests were done using dental cement spatulas coated with TiO2 and Ag nanoparticles (one or three layers), and contaminated with 10 mcrl of Pseudomonas aeruginosa and Enterococcus faecalis, respectively. After contamination, they were exposed to ultraviolet light and visible light for 120 minutes. Next, they were transferred to and stored in test tubes with BHI (Brain Heart Infusion) and incubated in 35 to 37 °C. Checking times for bacterial growth and for control and retrieval tests were done at: 24, 48, 72 and 96 hours. Result: The Pseudomonas aeruginosa was inactive after 120 minutes of ultraviolet light irradiation, thus confirming the heterogeneous photocatalytic activity of TiO2 and Ag. The Pseudomonas aeruginosa was not inactivated under visible light irradiation and the Enterococcus faecalis was not inactivated under UV and visible light irradiation of the dental cement spatulas coated with TiO2 and Ag nanoparticles in the readings to 96 hours, showing bacterial growth. Conclusion: There were no influence of one or three layers of TiO2 and Ag nanoparticles coating of the spatulas in the results. The heterogeneous photocatalysis activity of TiO2 and Ag under UV light irradiation was confirmed for Pseudomonas aeruginosa but not under visible light. Enterococcus faecalis did not confirmed the photocatalytics activity of TiO2 and Ag under UV light irradiation and visible lights irradiation.