2,058 research outputs found

    Near-Field Scanning Microwave Microscopy: Measuring Local Microwave Properties and Electric Field Distributions

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    We describe the near-field microwave microscopy of microwave devices on a length scale much smaller than the wavelength used for imaging. Our microscope can be operated in two possible configurations, allowing a quantitative study of either material properties or local electric fields.Comment: 4 pages, 8 figures, minor corrections to text and 2 figure

    Frequency Following Imaging of Electric Fields from Resonant Superconducting Devices using a Scanning Near-Field Microwave Microscope

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    We have developed a scanning near-field microwave microscope that operates at cryogenic temperatures. Our system uses an open-ended coaxial probe with a 200 mm inner conductor diameter and operates from 77 to 300 K in the 0.01-20 GHz frequency range. In this paper, we present microwave images of the electric field distribution above a Tl2Ba2CaCu2O8 microstrip resonator at 77 K, measured at several heights. In addition, we describe the use of a frequency-following circuit to study the influence of the probe on the resonant frequency of the device.Comment: 4 pages, postscript file with 6 figures conference proceeding for the Applied Superconductivity Conference 199

    Nitric oxide mediated effect of cyclo-oxygenase inhibitors

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    Objectives: Non-Steroidal anti-inflammatory drugs (NSAIDS) have long been used as anti-inflammatory agents, yet their mode of action is not entirely clear. The inhibitory effects of NSAIDS on prostaglandin production can only partly explain their anti-inflammatory actions. This study was aimed at defining the role of cycl-oxygenase (COX) inhibitors on nitric oxide (NO) production in murine macrophages in vitro.Methods: Murine macrophages were obtained from the peritoneum and after exposure, in vitro to lipopolysaccharide (LPS) produced nitrite, measured after 24 hours by Griess reaction. The macrophages were pre-incubated with aspirin or indomethacin before activation with LPS.Results: Treatment with aspirin resulted in an increase in nitric oxide production. A similar response was obtained with indomethacin treatment.Conclusion: This study shows that COX inhibitors significantly increase NO production in murine macrophages in vitro and this may be one of the mechanisms by which they exert their anti-inflammatory effects

    Imaging Microwave Electric Fields Using a Near-Field Scanning Microwave Microscope

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    By scanning a fine open-ended coaxial probe above an operating microwave device, we image local electric fields generated by the device at microwave frequencies. The probe is sensitive to the electric flux normal to the face of its center conductor, allowing different components of the field to be imaged by orienting the probe appropriately. Using a simple model of the microscope, we are able to interpret the system's output and determine the magnitude of the electric field at the probe tip. We show images of electric field components above a copper microstrip transmission line driven at 8 GHz, with a spatial resolution of approximately 200 μ\mum.Comment: 10 pages, 3 eps-figures, accepted by Appl. Phys. Let

    Microwave Near-Field Imaging of Electric Fields in a Superconducting Microstrip Resonator

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    We describe the use of a cryogenic near-field scanning microwave microscope to image microwave electric fields from superconducting and normal-metal microstrip resonators. The microscope employs an open-ended coaxial probe and operates from 77 to 300 K in the 0.01-20 GHz frequency range with a spatial resolution of about 200 mm. We describe the operation of the system and present microwave images of Cu and Tl2Ba2CaCu2O8 microstrip resonators, showing standing wave patterns at the fundamental and second harmonic frequencies.Comment: 9 pages, 3 eps figure

    Addressing the Increase of Gun Violence Related Deaths in the United States and How to Reduce Them

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    Several Americans lose their lives to gun violence every year. Gun-violence-related death rates have been increasing annually. In 2020, gun violence deaths significantly increased due to the insecurities surrounding the COVID-19 pandemic and the racial tensions in the United States. This capstone highlights the gravity of the issue of increased gun-violence-related deaths in America and discusses the history of gun laws in the US as well as the current gun laws. The effectiveness and ineffectiveness of current policies are examined based on the states they are applicable in. The data is compared to propose a policy that would possibly help decrease gun-related deaths in the US by encouraging gun permits that would be acquired after intensive background checks and psychological assessments. The proposal presents an action-forcing event, the history and background of gun laws, a policy proposal, a policy and political analysis of the policy, and a recommendation. Essentially, the recommendation is that the policy proposed should be implemented to see a decline in gun-violence deaths in the United States

    FSL-BM: Fuzzy Supervised Learning with Binary Meta-Feature for Classification

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    This paper introduces a novel real-time Fuzzy Supervised Learning with Binary Meta-Feature (FSL-BM) for big data classification task. The study of real-time algorithms addresses several major concerns, which are namely: accuracy, memory consumption, and ability to stretch assumptions and time complexity. Attaining a fast computational model providing fuzzy logic and supervised learning is one of the main challenges in the machine learning. In this research paper, we present FSL-BM algorithm as an efficient solution of supervised learning with fuzzy logic processing using binary meta-feature representation using Hamming Distance and Hash function to relax assumptions. While many studies focused on reducing time complexity and increasing accuracy during the last decade, the novel contribution of this proposed solution comes through integration of Hamming Distance, Hash function, binary meta-features, binary classification to provide real time supervised method. Hash Tables (HT) component gives a fast access to existing indices; and therefore, the generation of new indices in a constant time complexity, which supersedes existing fuzzy supervised algorithms with better or comparable results. To summarize, the main contribution of this technique for real-time Fuzzy Supervised Learning is to represent hypothesis through binary input as meta-feature space and creating the Fuzzy Supervised Hash table to train and validate model.Comment: FICC201

    Inhibition of Hepatitis C Virus 3a genotype entry through Glanthus Nivalis Agglutinin

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    <p>Abstract</p> <p>Background</p> <p>Hepatitis C Virus (HCV) has two envelop proteins E1 and E2 which is highly glycosylated and play an important role in cell entry. Inhibition of virus at entry step is an important target to find antiviral drugs against HCV. Glanthus Nivalis Agglutinin (GNA) is a mannose binding lectin which has tendency for specific recognition and reversible binding to the sugar moieties of a wide variety of glycoproteins of enveloped viruses.</p> <p>Results</p> <p>In the present study, HCV pseudoparticles (HCVpp) for genotype 3a were produced to investigate the ability of GNA to block the HCV entry. The results demonstrated that GNA inhibit the infectivity of HCVpp and HCV infected serum in a dose-dependent manner and resulted in 50% reduction of virus at 1 ± 2 μg concentration. Molecular docking of GNA and HCV glycoproteins (E1 and E2) showed that GNA inhibit HCV entry by binding N-linked glycans.</p> <p>Conclusion</p> <p>These results demonstrated that targeting the HCV glycans is a new approach to develop antiviral drugs against HCV.</p
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