99,649 research outputs found
Tracking Virus-Specific CD4+ T Cells during and after Acute Hepatitis C Virus Infection
No full textBackground. 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
No full textThe 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
No full textParylene 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
Factors Influencing Technology Acquisition Decisions of Recipient Pharmaceutical Firms in Taiwan
No full textBrain Segmentation ? A Case study of Biomedical Cloud Computing for Education and Research
No full textMedical imaging is widely adopted in Hospitals and medical institutes, and new ways to improve existing medical imaging services are regularly exploited. This paper describes the adoption of Cloud Computing is useful for medical education and research, and describes the methodology, results and lesson learned. A working Bioinformatics Cloud platform can demonstrate computation and visualisation of brain imaging. The aim is to study segmentation of brains, which divides the brain into ten major regions. The Cloud platform has these two functions: (i) it can highlight each region for ten different segments; and (ii) it can adjust intensity of segmentation to allow basic study of brain medicine. Two types of benefits are reported as follows. Firstly, all the medical student participants are reported to have 20% improvement in their learning satisfaction. Secondly, 100% of volunteer participants are reported to have positive learning experience
Antifungal activity of essential oil and its constituents from Calocedrus macrolepis var. formosana Florin leaf against plant pathogenic fungi
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