40,910 research outputs found

    Interleukin-17D and Nrf2 mediate initial innate immune cell recruitment and restrict MCMV infection.

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    Innate immune cells quickly infiltrate the site of pathogen entry and not only stave off infection but also initiate antigen presentation and promote adaptive immunity. The recruitment of innate leukocytes has been well studied in the context of extracellular bacterial and fungal infection but less during viral infections. We have recently shown that the understudied cytokine Interleukin (IL)-17D can mediate neutrophil, natural killer (NK) cell and monocyte infiltration in sterile inflammation and cancer. Herein, we show that early immune cell accumulation at the peritoneal site of infection by mouse cytomegalovirus (MCMV) is mediated by IL-17D. Mice deficient in IL-17D or the transcription factor Nuclear factor (erythroid-derived 2)-like 2 (Nrf2), an inducer of IL-17D, featured an early decreased number of innate immune cells at the point of viral entry and were more susceptible to MCMV infection. Interestingly, we were able to artificially induce innate leukocyte infiltration by applying the Nrf2 activator tert-butylhydroquinone (tBHQ), which rendered mice less susceptible to MCMV infection. Our results implicate the Nrf2/IL-17D axis as a sensor of viral infection and suggest therapeutic benefit in boosting this pathway to promote innate antiviral responses

    Chimeric Yellow Fever/Dengue Virus as a Candidate Dengue Vaccine: Quantitation of the Dengue Virus-Specific CD8 T-Cell Response

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    We have constructed a chimeric yellow fever/dengue (YF/DEN) virus, which expresses the premembrane (prM) and envelope (E) genes from DEN type 2 (DEN-2) virus in a YF virus (YFV-17D) genetic background. Immunization of BALB/c mice with this chimeric virus induced a CD8 T-cell response specific for the DEN-2 virus prM and E proteins. This response protected YF/DEN virus-immunized mice against lethal dengue encephalitis. Control mice immunized with the parental YFV-17D were not protected against DEN-2 virus challenge, indicating that protection was mediated by the DEN-2 virus prM- and E-specific immune responses. YF/DEN vaccine-primed CD8 T cells expanded and were efficiently recruited into the central nervous systems of DEN-2 virus challenged mice. At 5 days after challenge, 3 to 4% of CD8 T cells in the spleen were specific for the prM and E proteins, and 34% of CD8 T cells in the central nervous system recognized these proteins. Depletion of either CD4 or CD8 T cells, or both, strongly reduced the protective efficacy of the YF/DEN virus, stressing the key role of the antiviral T-cell response

    SN 2007uy - metamorphosis of an aspheric Type Ib explosion

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    The supernovae of Type Ibc are rare and the detailed characteristics of these explosions have been studied only for a few events. Unlike Type II SNe, the progenitors of Type Ibc have never been detected in pre-explosion images. So, to understand the nature of their progenitors and the characteristics of the explosions, investigation of proximate events are necessary. Here we present the results of multi-wavelength observations of Type Ib SN 2007uy in the nearby (\sim 29.5 Mpc) galaxy NGC 2770. Analysis of the photometric observations revealed this explosion as an energetic event with peak absolute R band magnitude 18.5±0.16-18.5\pm0.16, which is about one mag brighter than the mean value (17.6±0.6-17.6\pm0.6) derived for well observed Type Ibc events. The SN is highly extinguished, E(B-V) = 0.63±\pm0.15 mag, mainly due to foreground material present in the host galaxy. From optical light curve modeling we determine that about 0.3 M_{\odot} radioactive 56^{56}Ni is produced and roughly 4.4 M_{\odot} material is ejected during this explosion with liberated energy 15×1051\sim 15\times10^{51} erg, indicating the event to be an energetic one. Through optical spectroscopy, we have noticed a clear aspheric evolution of several line forming regions, but no dependency of asymmetry is seen on the distribution of 56^{56}Ni inside the ejecta. The SN shock interaction with the circumburst material is clearly noticeable in radio follow-up, presenting a Synchrotron Self Absorption (SSA) dominated light curve with a contribution of Free Free Absorption (FFA) during the early phases. Assuming a WR star, with wind velocity \ga 10^3 {\rm km s}^{-1}, as a progenitor, we derive a lower limit to the mass loss rate inferred from the radio data as \dot{M} \ga 2.4\times10^{-5} M_{\odot}, yr1^{-1}, which is consistent with the results obtained for other Type Ibc SNe bright at radio frequencies.Comment: 22 pages, 13 figures, accepted for publication in MNRA

    5,6-Dihydro-2H-pyran-3(4H)-on als Baustein zur Synthese pyrananellierter Heterocyclen

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    Während 5,6-Dihydro-2H-pyran-3(4H)-on (3) sich mit ortho-substituierten Phenylcarbonylverbindungen nur in Einzelfällen regioselektiv zu pyrananellierten Heterocyclen umsetzt - z. B. zum Pyrano[2,3-b]chinolin 7c -, gelingt das besser mit dem aus 3 hergestellten Enamin 15d, dem Silylenolether 18 und dem daraus gewonnenen Lithiumenolat 14. Diese Pyranderivate mit 2,3-oder 3,4-Doppelbindungen eignen sich zur gezielten Darstellung von 2- oder 4-substituierten 3-Pyranonen - z.B. 2, 21a, 21b, 23a-c, 26a-c, 31a-c, 32, sowie 35a-c - und von Pyrano[3,2-b]- oder -[3,4-b]chinolinen, -chinolonen, -chromonen und -thiochromonen 6a, 30a-c und 38a-d

    Radiation- and Bound-Mode Propagation in Rectangular, Multimode Dielectric, Channel Waveguides With Sidewall Roughness

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    This paper calculates and displays accurate radiation modes for rectangular, multimode dielectric, channel waveguides, for the first time, and introduces the new semianalytical calculation method used to find them, the radiation-mode Fourier decomposition method (RFDM), which is an extension of the Fourier decomposition method (FDM) for finding bound propagating modes. The optimum choice of non-linear conformal transformation parameters is discussed for achieving highest accuracy. Once the radiation modes are known, the coupling coefficients can be found between the bound and radiation modes, as well as those between the bound modes themselves, andhence, the propagation loss can be found. The paper adapts Marcuse's coupled power theory, for the first time, to enable it to model propagation in rectangular, multimode dielectric, channel waveguides suffering from one dimensional sidewall roughness enabling the equilibrium distance to be calculated, at which rate of loss to radiation modes becomes constant, and to find that equilibrium propagation loss, and the dependence on the statistical properties of the wall roughness. This leads to the conclusion that at sufficient distance there exist two uncoupled modes, a symmetric and an asymmetric lowest order mode

    The Importance of Boundary Conditions in Quantum Mechanics

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    We discuss the role of boundary conditions in determining the physical content of the solutions of the Schrodinger equation. We study the standing-wave, the ``in,'' the ``out,'' and the purely outgoing boundary conditions. As well, we rephrase Feynman's +iϵ+i \epsilon prescription as a time-asymmetric, causal boundary condition, and discuss the connection of Feynman's +iϵ+i \epsilon prescription with the arrow of time of Quantum Electrodynamics. A parallel of this arrow of time with that of Classical Electrodynamics is made. We conclude that in general, the time evolution of a closed quantum system has indeed an arrow of time built into the propagators.Comment: Contribution to the proceedings of the ICTP conference "Irreversible Quantum Dynamics," Trieste, Italy, July 200
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