401,251 research outputs found

    Chang, C. T.

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    Measuring and analyzing German and Spanish customer satisfaction of using the iPhone 4S Mobile Cloud service

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    This paper presents the customer satisfaction analysis for measuring popularity in the Mobile Cloud, which is an emerging area in the Cloud and Big Data Computing. Organizational Sustainability Modeling (OSM) is the proposed method used in this research. The twelve-month of German and Spanish consumer data are used for the analysis to investigate the return and risk status associated with the ratings of customer satisfaction in the iPhone 4S Mobile Cloud services. Results show that there is a decline in the satisfaction ratings in Germany and Spain due to economic downturn and competitions in the market, which support our hypothesis. Key outputs have been explained and they confirm that all analysis and interpretations fulfill the criteria for OSM. The use of statistical and visualization method proposed by OSM can expose unexploited data and allows the stakeholders to understand the status of return and risk of their Cloud strategies easier than the use of other data analysis

    Tracking Virus-Specific CD4+ T Cells during and after Acute Hepatitis C Virus Infection

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    Background. CD4+ T cell help is critical in maintaining antiviral immune responses and such help has been shown to be sustained in acute resolving hepatitis C. In contrast, in evolving chronic hepatitis C CD4+ T cell helper responses appear to be absent or short-lived, using functional assays. Methodology/Prencipal Findings. Here we used a novel HLA-DR1 tetramer containing a highly targeted CD4+ T cell epitope from the hepatitis C virus non-structural protein 4 to track number and phenotype of hepatitis C virus specific CD4+ T cells in a cohort of seven HLA-DR1 positive patients with acute hepatitis C in comparison to patients with chronic or resolved hepatitis C. We observed peptide-specific T cells in all seven patients with acute hepatitis C regardless of outcome at frequencies up to 0.65% of CD4+ T cells. Among patients who transiently controlled virus replication we observed loss of function, and/or physical deletion of tetramer+ CD4+ T cells before viral recrudescence. In some patients with chronic hepatitis C very low numbers of tetramer+ cells were detectable in peripheral blood, compared to robust responses detected in spontaneous resolvers. Importantly we did not observe escape mutations in this key CD4+ T cell epitope in patients with evolving chronic hepatitis C. Conclusions/Significance. During acute hepatitis C a CD4+ T cell response against this epitope is readily induced in most, if not all, HLA-DR1 + patients. This antiviral T cell population becomes functionally impaired or is deleted early in the course of disease in those where viremia persists

    Measurement of the ratio of prompt χ c to J / ψ production in pp collisions at √s = 7 TeV

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    The prompt production of charmonium χ c and J / ψ states is studied in proton-proton collisions at a centre-of-mass energy of √s = 7 TeV at the Large Hadron Collider. The χ c and J / ψ mesons are identified through their decays χ c → J / ψ γ and J / ψ → μ + μ - using 36 pb - 1 of data collected by the LHCb detector in 2010. The ratio of the prompt production cross-sections for χ c and J / ψ, σ (χ c → J / ψ γ) / σ (J / ψ), is determined as a function of the J / ψ transverse momentum in the range 2 < p T J / ψ < 15 GeV / c. The results are in excellent agreement with next-to-leading order non-relativistic expectations and show a significant discrepancy compared with the colour singlet model prediction at leading order, especially in the low p T J / ψ region

    Free-standing parylene C thin films as flexible pH sensing membranes

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    Parylene C has been extensively used as a biocompatible encapsulation material of implantable microdevices. Towards a new understanding of the material’s potential, we demonstrate a versatile method that enables the deployment of the material both as an encapsulant and as a H+ sensing membrane in a single flexible platform using discrete MOSFETs to evaluate its chemical sensing performance. A 40-electrode array was implemented through standard microfabrication techniques on a free-standing 5 µm film of Parylene. A thin film (1µm) of Parylene was finally deposited on top of the array to encapsulate the electrode tracks. O2 plasma treatment was employed to selectively functionalize Parylene’s H+ sensing capacity. Our investigation reveals that the fabricated sensor yields a reliable pH sensing device, which exhibits distinguishable sensitivity, low leakage currents and drift rates over a wide pH range (4-10), rendering Parylene a promising material in the field of flexible electronics

    Pihya C. Chang

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