Modelagem dos efeitos da irradiação luminosa no cérebro de camundongos e rastreamento de neurônios durante experimentos de microscopia de fluorescência

The fluorescent proteins are an essential tool in many fields of biology, since they allow us to watch the development of structures and dynamic processes of cells in living tissue, with the aid of fluorescence microscopy. Optogenectics is another technique that is currently widely used in Neuroscience. In general, this technique allows to activate/deactivate neurons with the radiation of certain wavelengths on the cells that have ion channels sensitive to light, at the same time that can be used with fluorescent proteins. This dissertation has two main objectives. Initially, we study the interaction of light radiation and mice brain tissue to be applied in optogenetic experiments. In this step, we model absorption and scattering effects using mice brain tissue characteristics and Kubelka-Munk theory, for specific wavelengths, as a function of light penetration depth (distance) within the tissue. Furthermore, we model temperature variations using the finite element method to solve Pennes’ bioheat equation, with the aid of COMSOL Multiphysics Modeling Software 4.4, where we simulate protocols of light stimulation tipically used in optogenetics. Subsequently, we develop some computational algorithms to reduce the exposure of neuron cells to the light radiation necessary for the visualization of their emitted fluorescence. At this stage, we describe the image processing techniques developed to be used in fluorescence microscopy to reduce the exposure of the brain samples to continuous light, which is responsible for fluorochrome excitation. The developed techniques are able to track, in real time, a region of interest (ROI) and replace the fluorescence emitted by the cells by a virtual mask, as a result of the overlay of the tracked ROI and the fluorescence information previously stored, preserving cell location, independently of the time exposure to fluorescent light. In summary, this dissertation intends to investigate and describe the effects of light radiation in brain tissue, within the context of Optogenetics, in addition to providing a computational tool to be used in fluorescence microscopy experiments to reduce image bleaching and photodamage due to the intense exposure of fluorescent cells to light radiation.

Riscos à saúde dos trabalhadores em unidade de alimentação e nutrição de um Hospital Universitário

The Food and Nutrition Units (FNU) are designed to produce food for healthy and/or sick communities and need to be done in a way to ensure the quality of foodstuffs that were produced. In these units, in the working environment, in general, there is excessive noise, heat and physical condition with many adaptations, presence of obstacles, inadequate flows, as well as the ways of the working organization may represent risks for workers health and lead to errors during production and/or distribution of food. The main goal of this study was to analyse the working processes in the Food Production Unit of the university’s hospital and identify the workers' health risk factors, using for this the knowledge of ergonomics, specifically the method of Ergonomic Work Analysis (EWA). After this analysis it was possible to develop proposals that will bring improvements to the working conditions, minimizing health risk factors during the process of meals production. It’s crucial to reassert this method considers the work activity performed in real time and highlights the importance of listening and the engagement of the workers in the changing process. It is a descriptive research with a qualitative approach. In the field research were collected demographics data, employment characteristics of the individuals (age, education, stocking sector, the total length of service and length of service in the industry) and data related to their usual work (task analysis, activity analysis and Analysis of the working environment) in the FNU. The instruments that were used in this study were document analysis, global and systematic observations and semi structured interviews in order to identify the main complaints related to those activities developed by them. The study was based on data for the analysis of Bardin, 2011, so the documents have been selected and including those that treat issues related to risks to workers' health were selected. The result of semi-structured interviews, global and systematic observations took place a confrontation of this material to the theoretical framework, held the inference and the interpretation of results the light of the knowledge of ergonomics and legislation. Issues related to the risks and the perception of workers has crafted a table showing the frequency of responses to the physical, chemical and biological and even the risk of accidents and was made a descriptive analysis. The results of this analysis indicated that the unit in question presents several problems ambience of jobs, both in terms of physical structure, but also in the organization of work. Non-conformities that leads to a favourable environment to the development of disease and injury hazards and compromising the quality of food produced. It is necessary to comply with legislation and that short, medium and long-term measures are taken to ensure the physical integrity of workers and improve the working environment.

Análise de desempenho de algoritmos de compressão de dados com perda para aplicações industriais

The great amount of data generated as the result of the automation and process supervision in industry implies in two problems: a big demand of storage in discs and the difficulty in streaming this data through a telecommunications link. The lossy data compression algorithms were born in the 90’s with the goal of solving these problems and, by consequence, industries started to use those algorithms in industrial supervision systems to compress data in real time. These algorithms were projected to eliminate redundant and undesired information in a efficient and simple way. However, those algorithms parameters must be set for each process variable, becoming impracticable to configure this parameters for each variable in case of systems that monitor thousands of them. In that context, this paper propose the algorithm Adaptive Swinging Door Trending that consists in a adaptation of the Swinging Door Trending, as this main parameters are adjusted dynamically by the analysis of the signal tendencies in real time. It’s also proposed a comparative analysis of performance in lossy data compression algorithms applied on time series process variables and dynamometer cards. The algorithms used to compare were the piecewise linear and the transforms.