Modelos in vitro para rastreio de fármacos

Cancer is the main target of research in the field of biology and pharmacology. Every year, thousands of cancer-related articles are published in specialized scientific journals. The development of new anticancer therapies is also one of the main interests of pharmaceutical companies. However, academia and big pharma have recently set their sights on cutting expenses related to drug development through co-operation protocols. Currently, various cellular viability assays (kits) are available in the market. However, most of these kits are expensive. To fulfill this need, there is a crescent demand for new protocols, such as cellular viability and cytotoxicity assays, that can be used for drug development in a faster and cheaper manner. In the present study, the application of Crystal Violet (CV), a compound that is relatively cheap, to determine the cellular viability of breast cancer and cervical cancer cells was evaluated. As no uniform and/or optimized CV cellular viability assay has been described in literature, the main focus of this work was the optimization procedure of a CV protocol, and its application for high-throughput screening (HTS) of new therapeutics. Two points of interest for the optimization of the protocol were considered: the possible fixation of cells and the concentration of the CV solution used for cell staining. The obtained results show there is an increase in absorbance proportional to the number of seeded cells for all CV protocol variations. The optimization procedure was successful, as it was shown that fixing and staining cells with a CV solution of higher concentration increased sensibility and decreased the variance of the signal/cell ratio in comparison with other tested protocols. It was also shown that the optimized CV assay may also be used as an alternative method for drug efficacy screening to other cellular viability assays widely described in literature, such as the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and Resazurin assays. It was also observed that the optimized CV assay may be applied for HTS of new anticancer drugs. Overall, as CV is a compound that is cheap to acquire, it may be used during anticancer drug development in the future.As doenças do foro oncológico são certamente o principal foco de investigação na área da biologia e da farmacologia. Por conseguinte, todos os anos são publicados milhares de artigos relativos a este tema em revistas da especialidade. O desenvolvimento de novas terapêuticas para tratamento do cancro é também do interesse das empresas farmacêuticas. Contudo, até aos dias de hoje, o custo associado ao desenvolvimento de fármacos continua muito elevado. Deste modo, as instituições académicas e as grandes empresas farmacêuticas têm vindo a estabelecer colaborações que visam a diminuição destes custos, nomeadamente os que incluem as despesas dos ensaios pré-clínicos. Atualmente existem vários ensaios de viabilidade celular em forma de kit que são usados durante os ensaios pré-clínicos. Contudo, a maioria destes kits são dispendiosos, o que tem despoletado uma necessidade crescente de desenvolver novos ensaios, que permitam avaliar o efeito terapêutico de novos fármacos com maior celeridade e menor custo. No presente estudo foi investigada a aplicação do Cristal Violeta (CV), um corante pouco dispendioso, para determinar a viabilidade celular de células cancerígenas do colo do útero e da mama. Uma vez que não existe qualquer ensaio padronizado e/ou otimizado para o uso deste composto para a determinação da viabilidade celular descrito na literatura, o principal foco deste trabalho passou pela otimização de um protocolo utilizando o CV para futura avaliação em larga escala (HTS) de fármacos. Durante a otimização do protocolo de CV para determinação da viabilidade celular foram considerados os seguintes pontos: fixação ou ausência de fixação das células e a concentração da solução de CV utilizada para marcar as células. Os resultados obtidos demonstraram que há um aumento de absorbância do CV proporcional ao aumento do número de células para todas as variações do ensaio de CV. O protocolo em que se procedeu à fixação das células e em que foi usada uma solução mais concentrada de CV foi escolhido como sendo o protocolo otimizado, i.e., mais adequado para determinar a viabilidade celular, uma vez que este demonstrou maior sensibilidade, precisão e menor variabilidade no rácio sinal/célula nos resultados obtidos. O ensaio otimizado de CV também permitiu avaliar a eficácia de um fármaco (Doxorubicina (DOX)) de forma semelhante a outros ensaios amplamente descritos na literatura, tal como é o caso do ensaio do brometo de 3-(4,5-dimetiltiazol-2-il)-2,5-difeniltetrazólio (MTT) e o da Resazurina. Foi ainda verificado que o ensaio otimizado de CV pode ser aplicado para HTS de novos fármacos. Em conclusão, sendo o CV um composto de baixo custo, este poderá possivelmente ser usado futuramente na investigação de fármacos para tratamento do cancro

Fitting latent non-Gaussian models using variational Bayes and Laplace approximations

Latent Gaussian models (LGMs) are perhaps the most commonly used class of models in statistical applications. Nevertheless, in areas ranging from longitudinal studies in biostatistics to geostatistics, it is easy to find datasets that contain inherently non-Gaussian features, such as sudden jumps or spikes, that adversely affect the inferences and predictions made from an LGM. These datasets require more general latent non-Gaussian models (LnGMs) that can handle these non-Gaussian features automatically. However, fast implementation and easy-to-use software are lacking, which prevent LnGMs from becoming widely applicable. In this paper, we derive variational Bayes algorithms for fast and scalable inference of LnGMs. The approximation leads to an LGM that downweights extreme events in the latent process, reducing their impact and leading to more robust inferences. It can be applied to a wide range of models, such as autoregressive processes for time series, simultaneous autoregressive models for areal data, and spatial Mat\'ern models. To facilitate Bayesian inference, we introduce the ngvb package, where LGMs implemented in R-INLA can be easily extended to LnGMs by adding a single line of code.Comment: 30 pages, 10 figure

Sea Surface Temperature and Chlorophyll-a spatial-temporal variation using MODIS-Aqua in the Todos os Santos Bay, Bahia, Brazil

In this study, the importance of MODIS sensor multispectral imagery on monitoring coastal and oceanic areas as well as marine ecosystems is demonstrated. As an example, the Todos os Santos Bay (TSB), BA, Brazil, was selected. Four 250m Sea Surface Temperature and Chlorophyll-a satellite-derived images were processed to characterize the TSB in 2009, as well as monthly time-series from July 2002 to January 2010 and monthly maps of 2009 off the coast of Bahia. These results were compared to the Brazilian Water Agency (ANA) discharge data and tidal data. They showed the importance of the latter in physical forcing compared to the former. Benefits from MODIS high temporal and spatial resolution data compared to other sensors to date allowed the characterization between different areas within the TSB

Robustness, model checking and latent Gaussian models

Model checking is essential to evaluate the adequacy of statistical models and the validity of inferences drawn from them. Particularly, hierarchical models such as latent Gaussian models (LGMs) pose unique challenges as it is difficult to check assumptions about the distribution of the latent parameters. Discrepancy measures are often used to quantify the degree to which a model fit deviates from the observed data. We construct discrepancy measures by (a) defining an alternative model with relaxed assumptions and (b) deriving the discrepancy measure most sensitive to discrepancies induced by this alternative model. We also promote a workflow for model criticism that combines model checking with subsequent robustness analysis. As a result, we obtain a general recipe to check assumptions in LGMs and the impact of these assumptions on the results. We demonstrate the ideas by assessing the latent Gaussianity assumption, a crucial but often overlooked assumption in LGMs. We illustrate the methods via examples utilising Stan and provide functions for easy usage of the methods for general models fitted through R-INLA.Comment: 40 pages, 21 figure

The sediment budget as a management tool: the Shoalhaven Coastal Compartment, southeastern NSW, Australia

Sediment budgets are fundamental approaches in coastal studies for allowing estimates of volumes of sediments entering and exiting a selected area of the coast, resulting in net erosion or accretion of that compartment under consideration. This assessment is crucial for understanding current processes and predicting future effects of sedimentimpact activities, promoting the sustainability of coastal environments over the next centuries. In this paper we present a series of preliminary spatial, sedimentological and geophysical analyses undertaken in order to understand the sources, sinks, transport and pathways for the sediment budget of the Shoalhaven coast, a compartment whose sediment provision is supplied primarily by the Shoalhaven River (draining a catchment of 7,151 km2) and that stretches ~32 km from the rocky headland of Black Head at Gerroa (north) to the Beecroft Peninsula near Currarong (south). Analysis included the use of sub-bottom profiler, ground penetrating radar, RTK-GPS, aerial photographs, satellite images, LiDAR, echosounding, computer modelling, as well as grain size parameters from ~200 sediment (and mineralogy for selected) samples from the estuary, beach and shoreface

Sophisticated colored packaging: the influence on purchase intention, perceived quality, product attractiveness, sophistication and willingness to pay

Dissertation presented as the partial requirement for obtaining a Master's degree in Information Management, specialization in Marketing IntelligenceWith the increasing number of products on the shelves, packaging has become increasingly important in consumers' purchasing decisions. Nowadays, packaging does not only serve to protect the product but it also serves as a space to communicate attracting consumers. Color is one of the most prominent elements of packaging and it has been seen as the tool that most influences consumer’s minds. However, previous research has only focused on primary colors or general color dimensions such as light/dark or warm/cold. Little research has been done into defining what sophisticated colors are. This study aimed to not only identify what are the colors considered sophisticated by consumers but also determine their influence on consumer purchase intention, perceived quality, product attractiveness, sophistication and finally, willingness to pay. It was also intended to find if the presence of the sophisticated colors on the packaging produced different effects between genders. This study used a questionnaire with 325 valid answers. The results showed that sophisticated colored packaging has a positive influence on all dependent variables: purchase intention, perceived quality, product attractiveness, sophistication and willingness to pay. The study also found that, color scenario impacts all dependent variables except product attractiveness of both genders in the same direction. Regarding, product attractiveness, contrary to expectations, it was observed that men are the gender that is more impacted by sophisticated colors

Relations between law, gender and Constitution: : (re)thinking constitutional history through women’s experiences

This article aims to analyze the importance of using gender categories in constitutional history research. To do so, after discussing the heterogeneous character of the discipline’s object of study and the claims for reassembling women’s experiences in historical analysis, it uses examples to demonstrate how the integration of gender conflicts into constitutional history is essential and how it contributes to the enrichment of this investigation field. Such examples encompass examining two main dimensions: the relations between constitutions and authoritarianism and the dynamics surrounding constituent processes and the constitutionalization of women’s rights. This exploratory, socio-legal study dwells on a bibliographical review of female and male authors that directly or indirectly tackle the topic. Lastly, the paper demonstrates the relevance of studies in constitutional history that question how gender inequality is reproduced by both law and politics, as well as of those that consider the strategies by which women work their ways to overcome inequality and assert their rights.  Este trabalho busca analisar a importânciado uso da categoria gênero nas pesquisas em história constitucional. Para tanto, após discutir o caráter heterogêneo do objeto de estudo da área e as demandas por recuperação de experiências femininas em análises históricas, demonstra, através de exemplos, como a integração de conflitos de gênero é necessária e enriquece esse campo de investigação. Tais exemplos envolvem a análise de duas dimensões de destaque: a das relações entre Constituição e autoritarismo e a das dinâmicas que circundam processos constituintes e a constitucionalização de direitos das mulheres. A pesquisa desenvolvida, de ordem exploratória e de natureza jurídico-sociológica, efetua uma revisão bibliográfica com base na produção de autoras e autores que se debruçam, direta ou indiretamente, sobre o tema. Ao fim, torna-se possível demonstrar a importância de que os estudos em história constitucional se ergam questionando a maneira pela qual as desigualdades de gênero são apropriadas pelo direitoe pela política, assim como os modos forjados pelas mulheres para contornarem essas desigualdades e reivindicarem seus direitos

Discursos sobre avaliação escolar e seus critérios : a perspectiva dos professores da ESEFID-UFRGS

A avaliação realizada por professores de educação física escolar tem sido um assunto controverso e com diversas transformações ao longo da história deste componente curricular. Enquanto no passado, a avaliação tinha um caráter estritamente punitivo e classificatório, hoje a avaliação possui diferentes objetivos e pode ser dividida em modelos: tradicional, mediador e emancipatório, de acordo com a literatura revisada. Ao longo da formação profissional em licenciatura em educação física a temática da avaliação se faz presente, no entanto, pode ser abordada de diferentes formas de acordo com os professores das disciplinas. Sendo assim, o objetivo desse trabalho é o de descrever: Como os professores do campo da Educação Física escolar do Curso de Licenciatura em Educação Física da ESEFID da UFRGS entendem o lugar do tema avaliação (e seus critérios) na formação profissional? Esta é uma pesquisa qualitativa. Os instrumentos para construção deste trabalho e busca de seus objetivos serão a análise bibliográfica sobre avaliação escolar em educação física e a realização de entrevistas semiestruturadas com os professores do curso de educação física da ESEFID responsáveis pelas disciplinas de fundamentos da educação infantil, ensino fundamental, médio, e ainda os responsáveis pelas orientações dos estágios docentes obrigatórios nos três níveis de ensino citados. Ao todo foram convidados a contribuir 7 professores, onde 3 se propuseram a participar da pesquisa. Concluo que os professores entrevistados entendem a avaliação como processual e formativa, e que é dentro do currículo um componente capaz de levantar questionamentos e debates positivos dentro da educação.The evaluation carried out by teachers of school physical education has been a controversial subject and with several transformations throughout the history of this curricular component. While in the past, the evaluation had a strictly punitive and classificatory character, today the evaluation has different objectives and can be divided into models: traditional, mediator and emancipatory, according to the revised literature. Throughout the professional training undergraduate in physical education the subject of evaluation is present, however, can be approached in different ways according to the teachers of the disciplines. Thus, the objective of this work is to describe: How do the teachers of the field of Physical Education of the School of Physical Education of ESFRID of UFRGS understand the place of the theme evaluation (and its criteria) in the professional formation? This is a qualitative research. The instruments for the construction of this work and search of its objectives will be the bibliographical analysis on school evaluation in physical education and the accomplishment of semi-structured interviews with the teachers of the physical education course of the ESEFID responsible for the disciplines of basic education, , and also those responsible for the orientation of compulsory teaching internships in the three levels of education mentioned. In all, 7 teachers were invited to contribute, where 3 proposed to participate in the research. I conclude that the interviewed teachers understand evaluation as procedural and formative, and that within the curriculum is a component capable of raising positive questions and debates within education