1,111 research outputs found

    Neuroprotection in a Novel Mouse Model of Multiple Sclerosis

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    The authors acknowledge the support of the Barts and the London Charity, the Multiple Sclerosis Society of Great Britain and Northern Ireland, the National Multiple Sclerosis Society, USA, notably the National Centre for the Replacement, Refinement & Reduction of Animals in Research, and the Wellcome Trust (grant no. 092539 to ZA). The siRNA was provided by Quark Pharmaceuticals. The funders and Quark Pharmaceuticals had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript

    High-speed imaging in fluids

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    High-speed imaging is in popular demand for a broad range of experiments in fluids. It allows for a detailed visualization of the event under study by acquiring a series of image frames captured at high temporal and spatial resolution. This review covers high-speed imaging basics, by defining criteria for high-speed imaging experiments in fluids and to give rule-of-thumbs for a series of cases. It also considers stroboscopic imaging, triggering and illumination, and scaling issues. It provides guidelines for testing and calibration. Ultra high-speed imaging at frame rates exceeding 1 million frames per second is reviewed, and the combination of conventional experiments in fluids techniques with high-speed imaging techniques are discussed. The review is concluded with a high-speed imaging chart, which summarizes criteria for temporal scale and spatial scale and which facilitates the selection of a high-speed imaging system for the applicatio

    Development of extrusion on demand for ceramic freeze-form extrusion fabrication processes

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    Freeze-form Extrusion Fabrication (FEF) is a Solid Freeform Fabrication method. It involves the deposition of a ceramic paste in a layer by layer manner to construct a three dimensional structure. The ceramic paste used in this process consists of a high solids loading of ceramic powder mixed with water and a nominal amount of an aqueous organic binder. These characteristics make the process environmentally friendly. Also the absence of dies or molds in the process makes it suitable for fabrication of materials like ceramics. In the past, parts have been fabricated with continuous extrusion of a ceramic paste. In FEF, Extrusion on Demand (EOD) refers to the ability to control the start and stop paste extrusion on command. Extrusion on Demand makes possible the fabrication of parts with complex geometries and internal features. The extrusion force is an important aspect to be controlled for the successful implementation of EOD in FEF. A general tracking controller with integral action is implemented to allow precise tracking of the reference force. Two possible methods of achieving EOD by controlling extrusion force and fine tuning process parameters have been discussed. Experiments are conducted to tune the controller and process parameters. Working ranges for all process parameters have been established. Three dimensional ceramic structures have been fabricated by using the parameter values obtained from the experiments --Abstract, page iv

    Fiber inline pressure and acoustic sensor fabricated with femtosecond laser

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    Pressure and acoustic measurements are required in many industrial applications such as down-hole oil well monitoring, structural heath monitoring, engine monitoring, study of aerodynamics, etc. Conventional sensors are difficult to apply due to the high temperature, electromagnetic-interference noise and limited space in such environments. Fiber optic sensors have been developed since the last century and have proved themselves good candidates in such harsh environment. This dissertation aims to design, develop and demonstrate miniaturized fiber pressure/acoustic sensors for harsh environment applications through femtosecond laser fabrication. Working towards this objective, the dissertation explored two types of fiber inline microsensors fabricated by femtosecond laser: an extrinsic Fabry-Perot interferometric (EFPI) sensor with silica diaphragm for pressure/acoustic sensing, and an intrinisic Fabry-Perot interferometer (IFPI) for temperature sensing. The scope of the dissertation work consists of device design, device modeling/simulation, laser fabrication system setups, signal processing method development and sensor performance evaluation and demonstration. This research work provides theoretical and experimental evidences that the femtosecond laser fabrication technique is a valid tool to fabricate miniaturized fiber optic pressure and temperature sensors which possess advantages over currently developed sensors --Abstract, page iii
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