1,322 research outputs found

    Omni-directional L-band antenna for mobile communications

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    The principle and design of an L-band omni-directional mobile communication antenna are discussed. The antenna is a circular wave guide aperture with hybrid circuits attached to higher order mode excitation. It produces polarized and symmetric two split beams in elevation. The circular waveguide is fed by eight probes with a 90 degree phase shift between their inputs. Radiation pattern characteristics are controlled by adjusting the aperture diameter and mode excitation. This antenna satisfies gain requirements as well as withstanding the harsh environment

    The prevalence of high dysplastic colonic adenomatous polyps in a 3 year endoscopic retrospective study from a single clinical center

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    Introduction: Many colon neoplastic tumors come from the malignancy of adenomatous polyps (70%-90%) that were not timely diagnosed in order to be resected. Materials and Methods: We conducted a retrospective study regarding the incidence of adenomatous polyps during 1.000 consecutive colonoscopies performed in our Upper and Lower Digestive Endoscopy Laboratory during a three-year period. Results: During these colonoscopies, some targeted polyps were biopsied or completely removed and the samples had been sent to a complete anatomopathological examination. Taking into consideration the results, the polyps were classified after the histological type and the form of dysplasia, in order to determine the polyp forms that present a high risk of malignancy. Conclusion: Given the rather high frequency of malignant polyps discovered during our study, we highly recommend colonoscopy as a method of choice for routine monitoring of selected cases

    Swimming Efficiency of Bacterium Escherichia Coli

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    We use in vivo measurements of swimming bacteria in an optical trap to determine fundamental properties of bacterial propulsion. In particular, we determine the propulsion matrix, which relates the angular velocity of the flagellum to the torques and forces propelling the bacterium. From the propulsion matrix dynamical properties such as forces, torques, swimming speed and power can be obtained from measurements of the angular velocity of the motor. We find significant heterogeneities among different individuals even though all bacteria started from a single colony. The propulsive efficiency, defined as the ratio of the propulsive power output to the rotary power input provided by the motors, is found to be 0.2%.Comment: 6 page

    Quality utility modelling for multimedia applications for Android mobile devices

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    With the advances in mobile technologies, smart mobile computing devices have become increasingly affordable and powerful, leading to a significant growth in both the number of advanced mobile users and their bandwidth demands. Moreover multimedia streaming to these high-end mobile devices has become widespread. However, multimedia applications are known to be resource-hungry and in order to cope with this explosion of data traffic, operators have started deploying different, overlapping radio access network technologies. One important challenge in such a heterogeneous wireless environment is to ensure an Always Best Experience to the mobile user, anywhere and anytime. This paper proposes the Quality Utility, a realistic mapping function of the received bandwidth to user satisfaction for multimedia streaming applications. The Quality Utility is mapped to a Google Nexus One Android Mobile device and validated through objective and subjective tests

    Arguments as abstract objects

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    In recent discussions concerning the definition of argument, it has been maintained that the word ‘argument’ exhibits the process-product ambiguity, or (as in Goddu forthcoming) an act/object ambi-guity. Drawing on literature on lexical ambiguity we argue that ‘argument’ is not ambiguous. The term ‘argument’ refers to an object, not to a speech act. We also examine some of the important implications of our argument by considering the question: what sort of abstract objects are arguments

    Shall Be Bright at Last: Reflections on Suffering and Hope in the Letters of Paul

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    These nine essays on suffering offer exercises in Christian hope. The contributors reveal honest and tender wounds of the many harsh realities of life in a broken world awaiting full redemption. They meditate on Paul\u27s holy words that teach us to pray with expectation and live by faith. They encourage fellow pilgrims to trust the path and stick together. Shall Be Bright at Last is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License, except where otherwise noted. CC BY-NC-SAhttps://digitalcommons.georgefox.edu/monographs/1000/thumbnail.jp

    iPSC-Derived Vascular Cell Spheroids as Building Blocks for Scaffold-Free Biofabrication

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    Recently a protocol is established to obtain large quantities of human induced pluripotent stem cells (iPSC)-derived endothelial progenitors, called endothelial colony forming cells (ECFC), and of candidate smooth-muscle forming cells (SMFC). Here, the suitability for assembling in spheroids, and in larger 3D cell constructs is tested. iPSC-derived ECFC and SMFC are labeled with tdTomato and eGFP, respectively. Spheroids are formed in ultra-low adhesive wells, and their dynamic proprieties are studied by time-lapse microscopy, or by confocal microscopy. Spheroids are also tested for fusion ability either in the wells, or assembled on the Regenova 3D bioprinter which laces them in stainless steel micro-needles (the “Kenzan” method). It is found that both ECFC and SMFC formed spheroids in about 24 h. Fluorescence monitoring indicated a continuous compaction of ECFC spheroids, but stabilization in those prepared from SMFC. In mixed spheroids, the cell distribution changed continuously, with ECFC relocating to the core, and showing pre-vascular organization. All spheroids have the ability of in-well fusion, but only those containing SMFC are robust enough to sustain assembling in tubular structures. In these constructs a layered distribution of alpha smooth muscle actin-positive cells and extracellular matrix deposition is found. In conclusion, iPSC-derived vascular cell spheroids represent a promising new cellular material for scaffold-free biofabrication
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