TY - JOUR A1 - Czerniuk, T. A1 - Brüggemann, C. A1 - Tepper, J. A1 - Brodbeck, S. A1 - Schneider, C. A1 - Kamp, M. A1 - Höfling, S. A1 - Glavin, B. A. A1 - Yakovlev, D. R. A1 - Akimov, A. V. A1 - Bayer, M. T1 - Lasing from active optomechanical resonators JF - Nature Communications N2 - Planar microcavities with distributed Bragg reflectors (DBRs) host, besides confined optical modes, also mechanical resonances due to stop bands in the phonon dispersion relation of the DBRs. These resonances have frequencies in the 10- to 100-GHz range, depending on the resonator's optical wavelength, with quality factors exceeding 1,000. The interaction of photons and phonons in such optomechanical systems can be drastically enhanced, opening a new route towards the manipulation of light. Here we implemented active semiconducting layers into the microcavity to obtain a vertical-cavity surface-emitting laser (VCSEL). Thereby, three resonant excitations--photons, phonons and electrons--can interact strongly with each other providing modulation of the VCSEL laser emission: a picosecond strain pulse injected into the VCSEL excites long-living mechanical resonances therein. As a result, modulation of the lasing intensity at frequencies up to 40 GHz is observed. From these findings, prospective applications of active optomechanical resonators integrated into nanophotonic circuits may emerge. KW - physical sciences KW - applied physics KW - optical physics Y1 - 2014 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-121559 VL - 5 ER - TY - JOUR A1 - Schneider-Schaulies, Sibylle A1 - Schneider-Schaulies, Jürgen A1 - Schuster, A. A1 - Bayer, M. A1 - Pavlovic, J. A1 - ter Meulen, V. T1 - Cell type specific MxA-mediated inhibition of measles virus transcription in human brain cells N2 - No abstract available KW - Virologie Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-62255 ER - TY - JOUR A1 - Schneider-Schaulies, Jürgen A1 - Schneider-Schaulies, S. A1 - Schuster, A. A1 - Bayer, M. A1 - Pavlovic, J. A1 - ter Meulen, V. T1 - Cell type specific MxA-mediated inhibition of measles virus transcription in human brain cells N2 - Measles virus (MV)-specific transcription in human brain cells is characterized by particularly low abundances of the distal mRNAs encoding the MV envelope proteins. Similar transcriptional restrictions of the closely related vesicular stomatitis virus have been observed in mouse fibroblasts constitutively expressing the interferon-inducible MxA protein (P. Staeheli and J. Pavlovic, J. Virol. 65:4498-4501, 1991). We found that MV infection of human brain cells is accompanied by rapid induction and high-level expression of endogenous MxA proteins. After stable transfection of MxA, human glioblastoma cells (U-87-MxA) released 50- to 100-fold less infectious virus and expression of viral proteinswas highly restricted. The overall MV-specific transcription Ievels were reduced by up to 90%, accompanied by low relative frequencies of the distal MV-specific mRNAs. These restrictions were linked to an inhibition of viral RNA synthesis and not to a decreased stability of the viral RNAs. Our results indicate that expression of MxA is associated with transcriptional attenuation of MV in brain cells, thus probably contributing to the establishment of persistent MV central nervous system infections. In addition, the mechanism of MxA-dependent resistance against MV infection, in contrast to that of vesicular Stomatitis virus, is cell type specific, because an inhibition of MV glycoprotein synthesis independent of transcriptional alterations was observed in MxA-transfected human monocytes Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-34313 ER - TY - JOUR A1 - Schneider-Schaulies, Sibylle A1 - Schneider-Schaulies, Jürgen A1 - Bayer, M. A1 - Löffler, S. A1 - ter Meulen, V. T1 - Spontaneous and differentiation dependent regulation of measles virus gene expression in human glial cells N2 - The expression of measles virus (MV) in six different permanent human glioma cell lines (D-54, U-251, U-138, U-105, U-373, and D-32) was analyzed. Although all celllines were permissive for productive replication of all MV strains tested, U-251, D-54, and D-32 cells spontaneously revealed restrictions of MV transcription similar to those observed for primary rat astroglial cells and brain tissue. In vitro differentiation of D-54 and U-251 cells by substances affecting tbe intracellular cyclic AMP Ievel caused a significant reduction of tbe expression of tbe viral proteins after 18, 72, and 144 b of infection. This pronounced restriction was not paralleled to a comparable Ievel by an inhibition of tbe syntbesis and biological activity in vitro of virus·specific mRNAs as sbown by quantitative Northem (RNA) blot analyses and in vitro translation. The block in viral protein syntbesis could not be attributed to tbe induction of type I interferon by any of tbe substances tested. Our findings indicate tbat down-regulation of MV gene expression in human brain cells can occur by a cell type-rlependent regulation of tbe viral mRNA transcription and a differentiation-dependent regulation of translation, botb of wbicb may be crucial for the establisbment of persistent MV infections in tbe centrat nervous system. KW - Immunologie Y1 - 1993 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-54913 ER -