169 research outputs found

    Investigations on the protective role of low-to-moderate alcohol consumption on high fat diet-induced non-alcoholic fatty liver disease

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    The proposed research project is based on the hypothesis that long-term low and moderate alcohol protects the liver from progression to NAFLD. The general objective of this thesis is to investigate the in vivo and in vitro effects of alcohol on NAFLD induced by HFD-fed rat model. The specific objectives of this thesis are (i) To elucidate the serum and histopathological changes observed by alcohol treatments on in vivo model, (ii) To elucidate the possible mechanism(s) of action of low and moderate alcohol on controlling HFD-induced NAFLD in the liver, (iii) elucidate the possible mechanism(s) of action of low and moderate alcohol on controlling FFA-induced NAFLD in HepG2 cells, (iv) evaluating the effect of alcohol on FFA-induced NAFLD in HeLa cells (LKB1-deficient cells) (v) evaluating the effect of alcohol on FFA-induced NAFLD in HepG2 cells in absence of AMPK, (vi) evaluating the effects of alcohol on FFA-induced NAFLD in HepG2 cells in absence of SIRT1

    Diffractive optics approach towards subwavelength pixels

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    Pixel size in cameras and other refractive imaging devices is typically limited by the free-space diffraction. However, a vast majority of semiconductor-based detectors are based on materials with substantially high refractive index. We demonstrate that diffractive optics can be used to take advantage of this high refractive index to reduce effective pixel size of the sensors below free-space diffraction limit. At the same time, diffractive systems encode both amplitude and phase information about the incoming beam into multiple pixels, offering the platform for noise-tolerant imaging with dynamical refocusing. We explore the opportunities opened by high index diffractive optics to reduce sensor size and increase signal-to-noise ratio of imaging structures.Comment: submitted to SPIE-DCS 201

    ISS Double-Gimbaled CMG Subsystem Simulation Using the Agile Development Method

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    This paper presents an evolutionary approach in simulating a cluster of 4 Control Moment Gyros (CMG) on the International Space Station (ISS) using a common sense approach (the agile development method) for concurrent mathematical modeling and simulation of the CMG subsystem. This simulation is part of Training systems for the 21st Century simulator which will provide training for crew members, instructors, and flight controllers. The basic idea of how the CMGs on the space station are used for its non-propulsive attitude control is briefly explained to set up the context for simulating a CMG subsystem. Next different reference frames and the detailed equations of motion (EOM) for multiple double-gimbal variable-speed control moment gyroscopes (DGVs) are presented. Fixing some of the terms in the EOM becomes the special case EOM for ISS's double-gimbaled fixed speed CMGs. CMG simulation development using the agile development method is presented in which customer's requirements and solutions evolve through iterative analysis, design, coding, unit testing and acceptance testing. At the end of the iteration a set of features implemented in that iteration are demonstrated to the flight controllers thus creating a short feedback loop and helping in creating adaptive development cycles. The unified modeling language (UML) tool is used in illustrating the user stories, class designs and sequence diagrams. This incremental development approach of mathematical modeling and simulating the CMG subsystem involved the development team and the customer early on, thus improving the quality of the working CMG system in each iteration and helping the team to accurately predict the cost, schedule and delivery of the software
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