133 results on '"Sven Reiche"'
Search Results
2. SwissFEL double bunch operation
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Martin Paraliev, Arturo Alarcon, Vladimir Arsov, Simona Bettoni, Roger Biffiger, Marco Boll, Hans Braun, Alessandro Citterio, Paolo Craievich, Andreas Josef Dax, Philipp Dijkstal, Sladana Dordevic, Eugenio Ferrari, Franziska Frei, Romain Ganter, Zheqiao Geng, Christopher Gough, Nicole Hiller, Martin Huppert, Rasmus Ischebeck, Pavle Juranic, Mario Jurcevic, Babak Kalantari, Roger Kalt, Boris Keil, Christoph Kittel, Waldemar Koprek, Daniel Llorente, Florian Löhl, Alexander Malyzhenkov, Fabio Marcellini, Goran Marinkovic, Gian Luca Orlandi, Cigdem Ozkan Loch, Marco Pedrozzi, Eduard Prat, Sven Reiche, Colette Rosenberg, Thomas Schietinger, Serguei Sidorov, Alexandre Trisorio, Carlo Vicario, Didier Voulot, Guanglei Wang, and Riccardo Zennaro
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Nuclear and High Energy Physics ,Physics and Astronomy (miscellaneous) ,Surfaces and Interfaces - Published
- 2022
3. Energy spread blowup by intrabeam scattering and microbunching at the SwissFEL injector
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Eduard Prat, Paolo Craievich, Philipp Dijkstal, Simone Di Mitri, Eugenio Ferrari, Thomas G. Lucas, Alexander Malyzhenkov, Giovanni Perosa, Sven Reiche, and Thomas Schietinger
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Nuclear and High Energy Physics ,Physics and Astronomy (miscellaneous) ,Surfaces and Interfaces - Abstract
We present high-resolution measurements of the electron beam energy spread at the SwissFEL injector as a function of the electron bunch charge, the optics, and the longitudinal dispersion of the lattice. The measured values are in general an order of magnitude higher than what is predicted by standard simulation codes. The measured dependences indicate that the energy spread blowup is caused primarily by intrabeam scattering and microbunching instabilities, effects not covered in the conventional modeling of radio-frequency injectors. We present further a numerical model that qualitatively reproduces the experimental data and an approach to mitigate the energy spread deterioration. The work underlines the importance of considering the energy spread in the optimization and design of high-brightness electron beam sources and the need to develop new models to adequately understand and simulate the observed physics effects., Physical Review Accelerators and Beams, 25 (10), ISSN:2469-9888
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- 2022
4. Performance of a SARS CoV-2 antibody ELISA based on simultaneous measurement of antibodies against the viral nucleoprotein and receptor-binding domain
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Andrea Aebischer, Torsten Schöneberg, Carolin Schnurra, Christian Jassoy, Thomas Hermsdorf, Sven Reiche, Nina Reiners, Henning Trawinski, and Judith Kannenberg
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0301 basic medicine ,Microbiology (medical) ,2019-20 coronavirus outbreak ,Coronavirus disease 2019 (COVID-19) ,Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) ,SARS CoV-2 ,Enzyme-Linked Immunosorbent Assay ,Antibodies, Viral ,Antibodies ,03 medical and health sciences ,COVID-19 Testing ,0302 clinical medicine ,Protein Domains ,Antigen ,Humans ,030212 general & internal medicine ,Nucleoprotein ,biology ,SARS-CoV-2 ,Chemistry ,Brief Report ,COVID-19 ,Spike Protein ,General Medicine ,Virology ,Receptor-binding domain ,Nucleoproteins ,030104 developmental biology ,Infectious Diseases ,biology.protein ,ELISA ,Antibody - Abstract
SARS CoV-2 antibody assays measure antibodies against the viral nucleoprotein (NP) or spike protein. The study examined if testing of antibodies against both antigens increases the diagnostic sensitivity. Sera (N=98) from infected individuals were tested with ELISAs based on the NP, receptor-binding domain (RBD), or both proteins. The AUROCs were 0.958 (NP), 0.991 (RBD), and 0.992 (NP/RBD). The RBD- and NP/RBD-based ELISAs showed better performance than the NP-based assay. Simultaneous testing for antibodies against NP and RBD increased the number of true and false positives. If maximum diagnostic sensitivity is required, the NP/RBD-based ELISA is preferable. Otherwise, the RBD-based ELISA is sufficient. Supplementary Information The online version contains supplementary material available at 10.1007/s10096-021-04284-5.
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- 2021
5. Mystery of fatal ‘Staggering disease’ unravelled: Novel rustrela virus causes severe encephalomyelitis in domestic cats
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Kaspar Matiasek, Florian Pfaff, Herbert Weissenböck, Claudia Wylezich, Jolanta Kolodziejek, Sofia Tengstrand, Frauke Ecke, Sina Nippert, Philip Starcky, Benedikt Litz, Jasmin Nessler, Peter Wohlsein, Christina Baumbach, Lars Mundhenk, Andrea Aebischer, Sven Reiche, Pia Weidinger, Karin M. Olofsson, Cecilia Rohdin, Christiane Weissenbacher-Lang, Julia Matt, Marco Rosati, Thomas Flegel, Birger Hörnfeldt, Dirk Höper, Rainer G. Ulrich, Norbert Nowotny, Martin Beer, Cecilia Ley, and Dennis Rubbenstroth
- Abstract
‘Staggering disease’ is a neurological disorder considered a threat to European domestic cats (Felis catus) for almost five decades. However, its aetiology has remained obscure. Rustrela virus (RusV), a relative of rubella virus, has recently been shown to be associated with encephalitis in a broad range of mammalian hosts. Here, we report the detection of RusV RNA and antigen by metagenomic sequencing, RT-qPCR, in-situ hybridization and immunohistochemistry in brain tissues of 28 out of 29 cats with non-suppurative meningoencephalomyelitis and ‘staggering disease’-like neurological disorder from Sweden, Austria, and Germany, but not in non-affected control cats. Screening of possible reservoir hosts in Sweden revealed RusV infection in wood mice (Apodemus sylvaticus). Our work strongly indicates RusV as the long-sought cause of feline ‘staggering disease’. Given its broad host spectrum and considerable geographic range, RusV may be the aetiological agent of neuropathologies in further mammals, possibly even including humans.
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- 2022
6. A compact and cost-effective hard X-ray free-electron laser driven by a high-brightness and low-energy electron beam
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Claudio Cirelli, Rafael Abela, Thomas J. Schmidt, Vladimir Arsov, Eduard Prat, Leonardo Sala, M. Aiba, B. Keil, Gian Luca Orlandi, Karol Nass, Luc Patthey, Marco Calvi, F. Marcellini, Rolf Follath, Terence Garvey, Daniela Kiselev, Martin Paraliev, Alexander Dietrich, Christian Erny, Steven L. Johnson, Albert Romann, Arturo Alarcon, Peter Radi, Henrik T. Lemke, Micha Dehler, Pavel Chevtsov, Bruce D. Patterson, Martin Huppert, Maik Kaiser, J. Alex, Jean-Yves Raguin, S. Redford, Christoph Kittel, Mathias Sander, Fabian Märki, Christopher Arrell, Jens Rehanek, Zheqiao Geng, Thomas Schietinger, A. Wrulich, Claude Pradervand, Simona Bettoni, Roger Biffiger, Simon Ebner, Elke Zimoch, Cigdem Ozkan Loch, Sladana Dordevic, Majed Chergui, C. Svetina, Gregor Knopp, Vincent Esposito, D. Treyer, Roger Kalt, C. Gough, A. Trisorio, A. Hauff, Paul Beaud, Hans-Heinrich Braun, Alexandre Gobbo, G. Marinkovic, Roberto Dinapoli, Rasmus Ischebeck, Marco Pedrozzi, Daniel Llorente Sancho, W. Koprek, Alexander Malyzhenkov, Eugenio Ferrari, Leonid Rivkin, Philip J. M. Johnson, Yunieski Arbelo, Romain Ganter, Mike Seidel, Carlo Vicario, A. Citterio, Roman Mankowsky, Gerhard Ingold, L. Stingelin, F. Frei, M. Bopp, Carl Beard, Stephan Hunziker, Florian Löhl, Ariana Cassar, Volker Schlott, Philipp Dijkstal, Paolo Craievich, Didier Voulot, Giulia F. Mancini, Sven Reiche, Daniel Engeler, Aldo Mozzanica, Pavle Juranić, Andreas Dax, Uwe Flechsig, Christopher J. Milne, Serhane Zerdane, Markus Janousch, Yunpei Deng, M. Jurcevic, Isabelle Martiel, Nicole Hiller, Tine Celcer, T. Schilcher, Christoph P. Hauri, Michael Laznovsky, M. Stadler, Bill Pedrini, Camila Bacellar, and Marta Csatari Divall
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Brightness ,Population ,02 engineering and technology ,Radiation ,01 natural sciences ,law.invention ,010309 optics ,Optics ,law ,0103 physical sciences ,Thermal emittance ,education ,single ,Physics ,education.field_of_study ,business.industry ,Free-electron laser ,021001 nanoscience & nanotechnology ,Laser ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,radiation ,Cathode ray ,Physics::Accelerator Physics ,statistical properties ,0210 nano-technology ,business ,Lasing threshold - Abstract
We present the first lasing results of SwissFEL, a hard X-ray free-electron laser (FEL) that recently came into operation at the Paul Scherrer Institute in Switzerland. SwissFEL is a very stable, compact and cost-effective X-ray FEL facility driven by a low-energy and ultra-low-emittance electron beam travelling through short-period undulators. It delivers stable hard X-ray FEL radiation at 1-A wavelength with pulse energies of more than 500 μJ, pulse durations of ~30 fs (root mean square) and spectral bandwidth below the per-mil level. Using special configurations, we have produced pulses shorter than 1 fs and, in a different set-up, broadband radiation with an unprecedented bandwidth of ~2%. The extremely small emittance demonstrated at SwissFEL paves the way for even more compact and affordable hard X-ray FELs, potentially boosting the number of facilities worldwide and thereby expanding the population of the scientific community that has access to X-ray FEL radiation. The first lasing results at SwissFEL, an X-ray free-electron laser, are presented, highlighting the facility’s unique capabilities. A general comparison to other major facilities is also provided.
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- 2020
7. Isolation and characterization of new Puumala orthohantavirus strains from Germany
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Florian Binder, Gleyder Roman-Sosa, Marion Saathoff, Sven Reiche, Dirk Höper, Dusan Kunec, Jakob Trimpert, René Ryll, and Rainer G. Ulrich
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medicine.drug_class ,600 Technik, Medizin, angewandte Wissenschaften::610 Medizin und Gesundheit::616 Krankheiten ,Antibodies, Viral ,Immunofluorescence ,Monoclonal antibody ,Puumala virus ,Virus ,glycoprotein-specific antibodies ,03 medical and health sciences ,chemistry.chemical_compound ,Germany ,Virology ,RNA polymerase ,Orthohepadnavirus ,Genetics ,medicine ,Animals ,Humans ,bank vole ,Molecular Biology ,030304 developmental biology ,puumala orthohantavirus ,Original Paper ,cell culture ,0303 health sciences ,biology ,medicine.diagnostic_test ,Strain (chemistry) ,030306 microbiology ,Antibodies, Monoclonal ,General Medicine ,virus adaptation ,biology.organism_classification ,Bank vole ,Titer ,chemistry ,biology.protein ,Antibody - Abstract
Orthohantaviruses are re-emerging rodent-borne pathogens distributed all over the world. Here, we report the isolation of a Puumala orthohantavirus (PUUV) strain from bank voles caught in a highly endemic region around the city Osnabrück, north-west Germany. Coding and non-coding sequences of all three segments (S, M, and L) were determined from original lung tissue, after isolation and after additional passaging in VeroE6 cells and a bank vole-derived kidney cell line. Different single amino acid substitutions were observed in the RNA-dependent RNA polymerase (RdRP) of the two stable PUUV isolates. The PUUV strain from VeroE6 cells showed a lower titer when propagated on bank vole cells compared to VeroE6 cells. Additionally, glycoprotein precursor (GPC)-derived virus-like particles of a German PUUV sequence allowed the generation of monoclonal antibodies that allowed the reliable detection of the isolated PUUV strain in the immunofluorescence assay. In conclusion, this is the first isolation of a PUUV strain from Central Europe and the generation of glycoprotein-specific monoclonal antibodies for this PUUV isolate. The obtained virus isolate and GPC-specific antibodies are instrumental tools for future reservoir host studies. Electronic supplementary material The online version of this article (10.1007/s11262-020-01755-3) contains supplementary material, which is available to authorized users.
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- 2020
8. Structure, Function, and Evolution of the Orthobunyavirus Membrane Fusion Glycoprotein
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Jan Hellert, Andrea Aebischer, Ahmed Haouz, Pablo Guardado-Calvo, Sven Reiche, Martin Beer, and Felix Augusto Rey
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History ,Polymers and Plastics ,Business and International Management ,Industrial and Manufacturing Engineering - Published
- 2022
9. Access and benefit-sharing by the European Virus Archive in response to COVID-19
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Jan Felix Drexler, Thomas C. Mettenleiter, Antonio Di Caro, Amber Hartman Scholz, Christian Drosten, Carrie Batten, Sven Reiche, Anthony R. Fooks, Bruno Coutard, Boris Klempa, Hervé Bourhy, Carolina dos S. Ribeiro, Florence Komurian-Pradel, Thomas Klimkait, Jean-Louis Romette, George B. Haringhuizen, Marion Koopmans, Christine M.A. Prat, Jean-Claude Manuguerra, Stephan Günther, Maria Serena Beato, Ali Mirazimi, Scarlett Sett, Rémi N. Charrel, David Williams, Chantal Reusken, Tatjana Avšič, Sylvie van der Werf, Leibniz-Institut DSMZ-Deutsche Sammlung von Mikroorganismen und Zellkulturen GmbH / Leibniz Institute DSMZ-German Collection of Microorganisms and Cell Cultures (DSMZ), Netherlands Center for Infectious Disease Control, Unité des Virus Emergents (UVE), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut National de la Santé et de la Recherche Médicale (INSERM), University of Ljubljana, The Pirbright Institute, Biotechnology and Biological Sciences Research Council (BBSRC), Istituto Zooprofilattico Sperimentale delle Venezie (IZSVe), Lyssavirus, épidémiologie et neuropathologie - Lyssavirus Epidemiology and Neuropathology, Institut Pasteur [Paris] (IP)-Université Paris Cité (UPCité), Istituto Nazionale di Malattie Infettive 'Lazzaro Spallanzani' (INMI), German Center for Infection Research, Partnersite Munich (DZIF), Charité - UniversitätsMedizin = Charité - University Hospital [Berlin], Animal and Plant Health Agency [Addlestone, UK] (APHA), Slovak Academy of Science [Bratislava] (SAS), Erasmus University Medical Center [Rotterdam] (Erasmus MC), University of Basel (Unibas), Bernhard Nocht Institute for Tropical Medicine - Bernhard-Nocht-Institut für Tropenmedizin [Hamburg, Germany] (BNITM), German Center for Infection Research - Partner Site Hamburg-Lübeck-Borstel-Riems, German Centre for Infection Research (DZIF), Cellule d'Intervention Biologique d'Urgence (Centre National de Référence) - Laboratory for Urgent Response to Biological Threats (National Reference Center) (CIBU), Université Paris Cité (UPCité)-Environnement et Risques infectieux - Environment and Infectious Risks (ERI), Institut Pasteur [Paris] (IP)-Université Paris Cité (UPCité)-Institut Pasteur [Paris] (IP), Environnement et Risques infectieux - Environment and Infectious Risks (ERI), Public Health Agency of Sweden, Friedrich-Loeffler-Institut (FLI), Fondation Mérieux, National Institute for Public Health and the Environment [Bilthoven] (RIVM), Aix Marseille Université (AMU), Génétique Moléculaire des Virus à ARN - Molecular Genetics of RNA Viruses (GMV-ARN (UMR_3569 / U-Pasteur_2)), Institut Pasteur [Paris] (IP)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Australian Centre for Disease Preparedness, Commonwealth Scientific and Industrial Research Organisation [Canberra] (CSIRO), This publication was supported by the European Virus Archive-GLOBAL project that has received funding from the EU Horizon 2020 research and innovation programme (grantagreement number 871029), The manuscript was written by the European Virus Archive access and benefit-sharing compliance team but would not have been possible without the front-line scientists that built up the European Virus Archive infrastructure and have worked tirelessly over the past year to support the global pandemic response. We welcome the European Virus Archive signatory authors who endorse this publication and its call for a multilateral pathogen genetic resources mechanism tied to a distributed biobanking infrastructure., European Virus Archive principal investigators Slovenia T Avšič (University of Ljubljana, Ljubljana). UK C Batten (The Pirbright Institute, Pirbright), A R Fooks (The Animal and Plant Health Agency, Addlestone). Italy M S Beato (Istituto Zooprofilattico Sperimentale delle Venezie, Legnaro), A Di Caro (Istituto Nazionale Malattie Infettive Lazzaro Spallanzani, Rome). France H Bourhy, J-C Manuguerra, S van der Werf (Institute Pasteur, Paris), R Charrel, J-L Romette, B Coutard (Aix Marseille University, Marseille), F Komurian-Pradel (Fondation Mérieux, Lyon). Germany J F Drexler, C Drosten (Charité–Universitätsmedizin Berlin, Berlin), S Günther (Bernhard Nocht Institute for Tropical Medicine, Hamburg), T C Mettenleiter, S Reiche (Friedrich Loeffler Institute, Greifswald). Slovakia B Klempa (Biomedical Research Center of the Slovak Academy of Sciences, Bratislava). Switzerland T Klimkait (University of Basel, Basel). Sweden A Mirazimi (The Public Health Agency of Sweden, Solna). Netherlands C Reusken (Dutch National Institute for Public Health and the Environment, Bilthoven), M Koopmans (Erasmus Medical Center, Rotterdam). Australia D Williams (Australian Centre for Disease Preparedness, East Geelong, VIC)., and European Project: 871029,H2020,H2020-INFRAIA-2019-1,EVA-GLOBAL(2020)
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Microbiology (medical) ,2019-20 coronavirus outbreak ,Coronavirus disease 2019 (COVID-19) ,Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) ,[SDV]Life Sciences [q-bio] ,Internet privacy ,Microbiology ,Corrections ,SDG 3 - Good Health and Well-being ,Genetic resources ,Virology ,Pandemic ,Humans ,Pandemics ,Biological Specimen Banks ,Personal View ,Benefit sharing ,business.industry ,SARS-CoV-2 ,DNA Viruses ,COVID-19 ,Biobank ,Infectious Diseases ,Viruses ,Viruses, Unclassified ,Business - Abstract
Erratum in Correction to Lancet Microbe 2021; published online Nov 16. https://doi.org/10.1016/S2666-5247(21)00211-1. [No authors listed] Lancet Microbe. 2022 Jan;3(1):e8. doi: 10.1016/S2666-5247(21)00325-6. Epub 2021 Nov 26. PMID: 34870252 Free PMC article.; International audience; Biobanking infrastructures, which are crucial for responding early to new viral outbreaks, share pathogen genetic resources in an affordable, safe, and impartial manner and can provide expertise to address access and benefit-sharing issues. The European Virus Archive has had a crucial role in the global response to the COVID-19 pandemic by distributing EU-subsidised (free of charge) viral resources to users worldwide, providing non-monetary benefit sharing, implementing access and benefit-sharing compliance, and raising access and benefit-sharing awareness among members and users. All currently available SARS-CoV-2 material in the European Virus Archive catalogue, including variants of concern, are not access and benefit-sharing cases per se, but multilateral benefit-sharing has nevertheless occurred. We propose and discuss how a multilateral system enabling access and benefit-sharing from pathogen genetic resources, based on the European Virus Archive operational model, could help bridge the discrepancies between the current bilateral legal framework for pathogen genetic resources and actual pandemic response practices.
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- 2021
10. The ACHIP experimental chambers at the Paul Scherrer Institut
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Simona Bettoni, Joshua McNeur, Christian David, Sven Reiche, Martin Bednarzik, F. Frei, Albert Romann, Terence Garvey, Vitaliy A. Guzenko, Simona Borrelli, Blagoj Sarafinov, Hans-Heinrich Braun, Eugenio Ferrari, Nicole Hiller, Eduard Prat, Gian Luca Orlandi, Marco Calvi, Micha Dehler, Rasmus Ischebeck, Leonid Rivkin, Peter Hommelhoff, and Cigdem Ozkan-Loch
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Physics ,Nuclear and High Energy Physics ,Interaction point ,Positioning system ,010308 nuclear & particles physics ,business.industry ,Electrical engineering ,Measure (physics) ,Free-electron laser ,Chip ,01 natural sciences ,0103 physical sciences ,Physics::Accelerator Physics ,010306 general physics ,business ,Instrumentation ,Beam (structure) - Abstract
The Accelerator on a Chip International Program (ACHIP) is an international collaboration, funded by the Gordon and Betty Moore Foundation, with the goal of demonstrating that laser-driven accelerator can be integrated on a chip to fully build an accelerator based on dielectric structures. PSI will provide access to the high brightness electron beam of SwissFEL to test structures, approaches and methods towards achieving the final goal of the project. In this contribution, we will describe the two interaction chambers installed on SwissFEL to perform the proof-of-principle experiments. In particular, we will present the positioning system for the samples, the magnets needed to focus the beam to sub-micrometer dimensions and the diagnostics to measure beam properties at the interaction point.
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- 2018
11. Monoclonal antibodies specific for the hemagglutinin-neuraminidase protein define neutralizing epitopes specific for Newcastle disease virus genotype 2.VII from Egypt
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Ibrahim Moharam, Sven Reiche, Olayinka Asala, Christian Grund, Timm C. Harder, Martin Beer, and Hafez M. Hafez
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Monoclonal antibody ,0301 basic medicine ,600 Technik, Medizin, angewandte Wissenschaften::630 Landwirtschaft::630 Landwirtschaft und verwandte Bereiche ,Genotype ,medicine.drug_class ,Newcastle Disease ,030106 microbiology ,Newcastle disease virus ,Infectious and parasitic diseases ,RC109-216 ,Biology ,Newcastle disease ,Epitope ,Antigenic drift ,Virus ,Epitopes ,Mice ,Viral Proteins ,03 medical and health sciences ,Antigen ,Virology ,medicine ,Animals ,Antigenic Drift and Shift ,Phylogeny ,Mice, Inbred BALB C ,HN Protein ,Research ,Antibodies, Monoclonal ,Antigenicity ,biology.organism_classification ,Conformational epitopes ,030104 developmental biology ,Infectious Diseases ,Genotype 2.VII ,Polyclonal antibodies ,biology.protein ,Hemagglutinin-Neuraminidase protein ,Egypt ,Chickens ,Hemagglutinin-neuraminidase - Abstract
Background Newcastle disease is a devastating disease in poultry caused by virulent Newcastle disease virus (NDV), a paramyxovirus endemic in many regions of the world despite intensive vaccination. Phylogenetic analyses reveal ongoing evolution of the predominant circulating genotype 2.VII, and the relevance of potential antigenic drift is under discussion. To investigate variation within neutralization-sensitive epitopes within the protein responsible for receptor binding, i.e. the Hemagglutinin-Neuraminidase (HN) spike protein, we were interested in establishing genotype-specific monoclonal antibodies (MAbs). Methods An HN-enriched fraction of a gradient-purified NDV genotype 2.VII was prepared and successfully employed to induce antibodies in BalbC mice that recognize conformationally intact sites reactive by haemagglutination inhibition (HI). For subsequent screening of mouse hybridoma cultures, an NDV-ELISA was established that utilizes Concanavalin A (ConA-ELISA) coupled glycoproteins proven to present conformation-dependent epitopes. Results Six out of nine selected MAbs were able to block receptor binding as demonstrated by HI activity. One MAb recognized an epitope only present in the homologue virus, while four other MAbs showed weak reactivity to selected other genotypes. On the other hand, one broadly cross-reacting MAb reacted with all genotypes tested and resembled the reactivity profile of genotype-specific polyclonal antibody preparations that point to minor antigenic differences between tested NDV genotpyes. Conclusions These results point to the concurrent presence of variable and conserved epitopes within the HN molecule of NDV. The described protocol should help to generate MAbs against a variety of NDV strains and to enable in depth analysis of the antigenic profiles of different genotypes.
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- 2021
12. Temporal diagnostics of the electron and photon beams at a free-electron laser with a corrugated passive structure
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Eduard Prat Costa, Sven Reiche, Alexander Malyzhenkov, Philipp Dijkstal, Pavle Juranić, Paolo Craievich, Eugenio Ferrari, and Thomas Schietinger
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Optics ,Materials science ,business.industry ,Free-electron laser ,Photon beams ,Electron ,business - Published
- 2021
13. Anti-SARS-CoV-2 Spike Protein and Anti-Platelet Factor 4 Antibody Responses Induced by COVID-19 Disease and ChAdOx1 nCov-19 vaccination
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Julia Mayerle, Daniel Duerschmied, Raghavendra Palankar, Siegbert Rieg, Kathleen Selleng, Agnes Flöel, Theodore E. Warkentin, Antje Vogelgesang, Meinrad Gawaz, Maximilian Muenchhoff, Sven Reiche, Guglielmo Lucchese, Oliver T. Keppler, Andreas Greinacher, Jan Wesche, Klaus Hahnenkamp, Matthias Napp, Karin Mueller, Angela Stufano, Christian Scheer, Piero Lovreglio, Rolf Marschalek, Achim Lother, Andrea Aebischer, Johannes C. Hellmuth, and Thomas Thiele
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Vaccination ,Antibody response ,Coronavirus disease 2019 (COVID-19) ,business.industry ,Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) ,Immunology ,Medicine ,Spike Protein ,Disease ,business ,Anti platelet ,Platelet factor 4 - Abstract
Background: Some recipients of ChAdOx1 nCoV-19 COVID-19 Vaccine AstraZeneca develop antibody-mediated vaccine-induced thrombotic thrombocytopenia (VITT), associated with cerebral venous and other unusual thrombosis resembling autoimmune heparin-induced thrombocytopenia. A prothrombotic predisposition is also observed in Covid-19. We explored whether antibodies against the SARS-CoV-2 spike protein induced by Covid-19 cross-react with platelet factor 4 (PF4/CXLC4), the protein targeted in both VITT and autoimmune heparin-induced thrombocytopenia.Methods: Immunogenic epitopes of PF4 and SARS-CoV-2 spike protein were compared via prediction tools and 3D modelling software (IMED, SIM, MacMYPOL). Sera from 222 PCR-confirmed Covid-19 patients from five European centers were tested by PF4/heparin ELISA, heparin-dependent and PF4-dependent platelet activation assays. Immunogenic reactivity of purified anti-PF4 and anti-PF4/heparin antibodies from patients with VITT were tested against recombinant SARS-CoV-2 spike protein. Results: Three motifs within the spike protein sequence share a potential immunogenic epitope with PF4. Nineteen of 222 (8.6%) Covid-19 patient sera tested positive in the IgG-specific PF4/heparin ELISA, none of which showed platelet activation in the heparin-dependent activation assay, including 10 (4.5%) of the 222 Covid-19 patients who developed thromboembolic complications. Purified anti-PF4 and anti-PF4/heparin antibodies from two VITT patients did not show cross-reactivity to recombinant SARS-CoV-2 spike protein. Conclusions: The antibody responses to PF4 in SARS-CoV-2 infection and after vaccination with COVID-19 Vaccine AstraZeneca differ. Antibodies against SARS-CoV-2 spike protein do not cross-react with PF4 or PF4/heparin complexes through molecular mimicry. These findings make it very unlikely that the intended vaccine-induced immune response against SARS-CoV-2 spike protein would itself induce VITT.
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- 2021
14. Single- and two-color attosecond hard x-ray free-electron laser pulses with nonlinear compression
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Eduard Prat, Yunieski Arbelo, Pavle Juranić, Alexander Malyzhenkov, Thomas Schietinger, Eugenio Ferrari, Philipp Dijkstal, Paolo Craievich, and Sven Reiche
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Work (thermodynamics) ,Materials science ,010308 nuclear & particles physics ,business.industry ,Attosecond ,Free-electron laser ,Electron ,01 natural sciences ,Nonlinear system ,Optics ,Compression (functional analysis) ,0103 physical sciences ,Coulomb ,010306 general physics ,business ,Beam (structure) - Abstract
This work describes a method for the generation of one and two-color ultra-short X-ray free-electron-laser pulses, based on tailoring the Coulomb interaction between the electrons of a highly compressed beam in the nonlinear regime.
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- 2020
15. High-resolution dispersion-based measurement of the electron beam energy spread
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Eugenio Ferrari, Alexander Malyzhenkov, Philipp Dijkstal, Eduard Prat, and Sven Reiche
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Physics ,Nuclear and High Energy Physics ,Physics and Astronomy (miscellaneous) ,010308 nuclear & particles physics ,business.industry ,Resolution (electron density) ,Surfaces and Interfaces ,Electron ,Laser ,01 natural sciences ,Streaking ,law.invention ,Optics ,Deflection (physics) ,law ,0103 physical sciences ,Cathode ray ,lcsh:QC770-798 ,Physics::Accelerator Physics ,lcsh:Nuclear and particle physics. Atomic energy. Radioactivity ,010306 general physics ,business ,Energy (signal processing) ,Beam (structure) - Abstract
The energy spread of the electron beam is a critical parameter in x-ray free-electron lasers (XFELs) and needs to be optimized for best performance. The uncorrelated energy spread of the electrons can be a few keV or less in XFEL injectors, thus very challenging to measure. The standard method to characterize the electron beam energy spread, consisting in streaking the beam with a transverse deflector and measuring the time-resolved beam size of the electrons in a dispersive location for a single electron beam energy, has a typical resolution of several keV. To overcome this limitation we introduce a novel method to measure the beam size at a dispersive location for different beam energies so that it is possible to disentangle the beam size contributions related to the energy spread, the intrinsic beam size and the monitor resolution. As a consequence, the energy spread can be characterized with a much higher precision and resolution than in the standard approach. We also suggest to perform measurements for different deflection amplitudes so that the energy spread induced by the transverse deflector can be subtracted properly. The scheme does not require any additional hardware and thus can be readily applied in any standard XFEL facility. Numerical simulations and experimental results at SwissFEL confirm the validity of our method. Our calculations show that the approach can be used to significantly overcome the resolution of the standard approach and measure energy spreads well below 1 keV. As an example we present energy spreads of few keV measured at the SwissFEL injector., Physical Review Accelerators and Beams, 23 (9), ISSN:2469-9888
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- 2020
16. The Ebola Virus Nucleoprotein Recruits the Nuclear RNA Export Factor NXF1 into Inclusion Bodies to Facilitate Viral Protein Expression
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Janine Brandt, Thomas Hoenen, Bianca S Bodmer, Sven Reiche, Marie Luisa Schmidt, Shelby Traeger, and Lisa Wendt
- Subjects
0301 basic medicine ,Gene Expression Regulation, Viral ,filovirus ,Nucleocytoplasmic Transport Proteins ,Viral protein ,viruses ,NXF1 ,Biology ,medicine.disease_cause ,Virus Replication ,Virus ,Inclusion bodies ,Article ,03 medical and health sciences ,Viral Proteins ,Ebola virus ,0302 clinical medicine ,Viral life cycle ,medicine ,Humans ,RNA, Messenger ,lcsh:QH301-705.5 ,Inclusion Bodies ,mRNA export ,liquid organelles ,RNA ,RNA-Binding Proteins ,General Medicine ,Ebolavirus ,Virology ,Nucleoprotein ,030104 developmental biology ,HEK293 Cells ,Nucleoproteins ,lcsh:Biology (General) ,030220 oncology & carcinogenesis ,RNA, Viral - Abstract
Ebola virus (EBOV) causes severe outbreaks of viral hemorrhagic fever in humans. While virus-host interactions are promising targets for antivirals, there is only limited knowledge regarding the interactions of EBOV with cellular host factors. Recently, we performed a genome-wide siRNA screen that identified the nuclear RNA export factor 1 (NXF1) as an important host factor for the EBOV life cycle. NXF1 is a major component of the nuclear mRNA export pathway that is usurped by many viruses whose life cycles include nuclear stages. However, the role of NXF1 in the life cycle of EBOV, a virus replicating in cytoplasmic inclusion bodies, remains unknown. In order to better understand the role of NXF1 in the EBOV life cycle, we performed a combination of co-immunoprecipitation and double immunofluorescence assays to characterize the interactions of NXF1 with viral proteins and RNAs. Additionally, using siRNA-mediated knockdown of NXF1 together with functional assays, we analyzed the role of NXF1 in individual aspects of the virus life cycle. With this approach we identified the EBOV nucleoprotein (NP) as a viral interaction partner of NXF1. Further studies revealed that NP interacts with the RNA-binding domain of NXF1 and competes with RNA for this interaction. Co-localization studies showed that RNA binding-deficient, but not wildtype NXF1, accumulates in NP-derived inclusion bodies, and knockdown experiments demonstrated that NXF1 is necessary for viral protein expression, but not for viral RNA synthesis. Finally, our results showed that NXF1 interacts with viral mRNAs, but not with viral genomic RNAs. Based on these results we suggest a model whereby NXF1 is recruited into inclusion bodies to promote the export of viral mRNA:NXF1 complexes from these sites. This would represent a novel function for NXF1 in the life cycle of cytoplasmically replicating viruses, and may provide a basis for new therapeutic approaches against EBOV, and possibly other emerging viruses.
- Published
- 2019
17. Demonstration of Large Bandwidth Hard X-Ray Free-Electron Laser Pulses at SwissFEL
- Author
-
Sven Reiche, Philipp Dijkstal, Eugenio Ferrari, and Eduard Prat
- Subjects
Photon ,Materials science ,business.industry ,Bandwidth (signal processing) ,Free-electron laser ,Physics::Optics ,General Physics and Astronomy ,Laser ,01 natural sciences ,law.invention ,Optics ,law ,0103 physical sciences ,Broadband ,Chirp ,Cathode ray ,Physics::Accelerator Physics ,010306 general physics ,business ,Quadrupole magnet - Abstract
We have produced hard x-ray free-electron laser (FEL) radiation with unprecedented large bandwidth tunable up to 2%. The experiments have been carried out at SwissFEL, the x-ray FEL facility at the Paul Scherrer Institute in Switzerland. The bandwidth is enhanced by maximizing the energy chirp of the electron beam, which is accomplished by optimizing the compression setup. We demonstrate continuous tunability of the bandwidth with a simple method only requiring a quadrupole magnet. The generation of such broadband FEL pulses will improve the efficiency of many techniques such as x-ray crystallography and spectroscopy, opening the door to significant progress in photon science. It has already been demonstrated that the broadband pulses of SwissFEL are beneficial to enhance the performance of crystallography, and further SwissFEL users plan to exploit this large bandwidth radiation to improve the efficiency of their measurement techniques.
- Published
- 2019
18. Generation and Characterization of Intense Ultralow-Emittance Electron Beams for Compact X-Ray Free-Electron Lasers
- Author
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Alexander Malyzhenkov, Eugenio Ferrari, Sven Reiche, Florian Löhl, Thomas Schietinger, Philipp Dijkstal, Paolo Craievich, Simona Bettoni, M. Aiba, Gianluca Orlandi, Rasmus Ischebeck, and Eduard Prat
- Subjects
Free electron model ,Physics ,business.industry ,General Physics and Astronomy ,Electron ,Undulator ,Radiation ,Laser ,01 natural sciences ,Linear particle accelerator ,law.invention ,Optics ,law ,0103 physical sciences ,Cathode ray ,Physics::Accelerator Physics ,Thermal emittance ,010306 general physics ,business - Abstract
The transverse emittance of the electron beam is a fundamental parameter in linac-based x-ray free-electron lasers (FELs). We present results of emittance measurements carried out at SwissFEL, a compact x-ray FEL facility at the Paul Scherrer Institute in Switzerland, including a description of the novel high-resolution measurement techniques and the optimization procedure. We obtained slice emittance values at the undulator entrance down to 200 nm for an electron beam with a charge of 200 pC and an rms duration of 30--40 fs. Furthermore, we achieved slice emittances as low as 100 nm for 10 pC beams with few fs duration. These values set new standards for electron linear accelerators. The quality, verification, and control of our electron beams allowed us to generate high-power FEL radiation for a wavelength as short as 0.1 nm using an electron beam with an energy of only 6 GeV. The emittance values demonstrated at SwissFEL would allow producing hard x-ray FEL pulses with even lower-energy beams, thus paving the way for even more compact and cost-effective FEL facilities.
- Published
- 2019
19. High seroprevalence of dengue virus indicates that dengue virus infections are frequent in central and eastern Sudan
- Author
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Christian Jassoy, Sven Reiche, Awadalkareem Adam, and Tom Schüttoff
- Subjects
Adult ,Male ,0301 basic medicine ,Serotype ,Adolescent ,030106 microbiology ,030231 tropical medicine ,Population ,Dengue virus ,medicine.disease_cause ,Serology ,Dengue fever ,Dengue ,Sudan ,Young Adult ,03 medical and health sciences ,0302 clinical medicine ,Seroepidemiologic Studies ,medicine ,Humans ,Seroprevalence ,Outpatient clinic ,Child ,education ,Aged ,Aged, 80 and over ,education.field_of_study ,business.industry ,Public Health, Environmental and Occupational Health ,Infant ,Dengue Virus ,Middle Aged ,medicine.disease ,Virology ,Infectious Diseases ,Child, Preschool ,Female ,Parasitology ,business - Abstract
Objectives To determine the seroprevalence of dengue in central and eastern Sudan and the breadth of neutralising antibody responses. Methods Blood was drawn from 483 patients with fever who visited outpatient clinics in Port Sudan, Red Sea state, in three towns in Kassala state and in El Obeid, North Kordofan, in December 2012 and January 2013. Sera were tested for dengue virus IgG and IgM by ELISA (Panbio) and sera without serologic evidence of acute infection (IgM negative) were used for the analysis of the seroprevalence. DENV neutralisation tests were performed to determine the specificity of the ELISA and to examine the degree of cross-neutralisation of multiple DENV serotypes. Results Sixty-seven per cent (302 of 448) of the sera were dengue virus IgG-positive. The seroprevalence in Port Sudan was 89% (106 of 119 sera), in Kassala 61% (128 of 209) and in North Kordofan 56.7% (68 of 120). Thirty-one of 32 ELISA-positive sera neutralised dengue viruses indicating that the ELISA was highly specific. The majority of the sera broadly neutralised all four dengue virus serotypes indicating multiple infections. Conclusions The majority of the population in central and eastern Sudan has been infected with dengue viruses, many people repeatedly. The high seroprevalence underscores the need for extended dengue surveillance in Sudan, broad disease awareness in medical institutions and in the population and diagnostic capacity building for severe dengue infections.
- Published
- 2018
20. Schmallenberg virus non-structural protein NSm: Intracellular distribution and role of non-hydrophobic domains
- Author
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Ilona Reimann, Sven Reiche, Andrea Aebischer, Franziska Kraatz, Kerstin Wernike, and Martin Beer
- Subjects
0301 basic medicine ,Orthobunyavirus ,Mutant ,Golgi Apparatus ,Viral Nonstructural Proteins ,Bunyaviridae Infections ,Virus ,Mice ,03 medical and health sciences ,Protein Domains ,Virology ,Animals ,Sequence Deletion ,chemistry.chemical_classification ,Mice, Inbred BALB C ,biology ,Schmallenberg virus ,biology.organism_classification ,Molecular biology ,Reverse genetics ,Transmembrane protein ,Protein Transport ,030104 developmental biology ,chemistry ,Glycoprotein ,Intracellular - Abstract
Schmallenberg virus (SBV) induces fetal malformation, abortions and stillbirth in ruminants. While the non-structural protein NSs is a major virulence factor, the biological function of NSm, the second non-structural protein which consists of three hydrophobic transmembrane (I, III, V) and two non-hydrophobic regions (II, IV), is still unknown. Here, a series of NSm mutants displaying deletions of nearly the entire NSm or of the non-hydrophobic domains was generated and the intracellular distribution of NSm was assessed. SBV-NSm is dispensable for the generation of infectious virus and mutants lacking domains II - V showed growth properties similar to the wild-type virus. In addition, a comparable intracellular distribution of SBV-NSm was observed in mammalian cells infected with domain II mutants or wild-type virus. In both cases, NSm co-localized with the glycoprotein Gc in the Golgi compartment. However, domain IV-deletion mutants showed an altered distribution pattern and no co-localization of NSm and Gc.
- Published
- 2018
21. Compact coherence enhancement by subharmonic self-seeding in X-ray free-electron laser facilities
- Author
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Eduard Prat and Sven Reiche
- Subjects
Nuclear and High Energy Physics ,Brightness ,Photon ,01 natural sciences ,law.invention ,Optics ,free-electron laser ,law ,0103 physical sciences ,High harmonic generation ,X-ray coherence ,010306 general physics ,Instrumentation ,Physics ,Radiation ,010308 nuclear & particles physics ,Scattering ,business.industry ,Free-electron laser ,self-seeding ,Undulator ,Laser ,Research Papers ,Physics::Accelerator Physics ,simulations ,business ,Coherence (physics) - Abstract
A simple method to significantly enhance the coherence of X-ray free-electron laser (FEL) pulses by combining self-seeding and the harmonic generation mechanism is presented. This work is a fundamental step towards obtaining fully coherent FEL pulses, solving in this way a critical problem in the FEL field and its multidisciplinary scientific applications. In particular, the coherence improvement will be extremely beneficial for many photon science applications requiring a small bandwidth such as resonant inelastic X-ray scattering, therefore opening new areas of research and playing a crucial role in the future of all scientific users of the FEL facilities., X-ray free-electron lasers (FELs) are cutting-edge scientific tools able to generate transversely coherent radiation with very high power and ultra-short pulse durations. The self-seeding mechanism has been proven to increase the longitudinal coherence of the FEL radiation but its efficiency could be significantly improved, especially for soft X-rays. This paper proposes the enhancement of the performance of self-seeding by combining it with the harmonic generation mechanism. In particular, by starting the process with a subharmonic of the wavelength of interest, the coherence of the produced radiation is improved, the undulator beamline becomes more compact, and the monochromator realization is simplified. Numerical simulations for SwissFEL are presented showing that the method can be employed, within a given space, to increase the spectral brightness by one order of magnitude or more with respect to standard self-seeding. This coherence enhancement will be fundamental for many photon science applications and techniques such as resonant inelastic X-ray scattering.
- Published
- 2018
22. Demonstration of a compact x-ray free-electron laser using the optical klystron effect
- Author
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Eugenio Ferrari, Romain Ganter, Sven Reiche, Thomas J. Schmidt, Eduard Prat, and Marco Calvi
- Subjects
Physics ,Physics and Astronomy (miscellaneous) ,Klystron ,business.industry ,Free-electron laser ,Radiation ,Undulator ,Laser ,law.invention ,Wavelength ,Optics ,Beamline ,law ,Dispersion (optics) ,business - Abstract
We demonstrate the operation of a compact x-ray free-electron laser (FEL) using the optical klystron mechanism. This effect speeds up the FEL process using the dispersion of magnetic chicanes placed between the undulator modules of the FEL beamline. The demonstration was performed at the soft x-ray beamline of SwissFEL, called Athos, which is, as far as we are aware, the only x-ray FEL to date with magnetic chicanes between every two undulator modules. In our measurements, we show that, compared to standard operation without chicanes, the required undulator length to achieve FEL saturation is reduced between 15% and 30% for radiation wavelengths between 1 and 2 nm. Fully exploiting the optical klystron effect represents an important step toward more compact FEL designs, rendering this key technology more affordable and hence accessible to a larger science community.
- Published
- 2021
23. Enhanced X-ray free-electron-laser performance from tilted electron beams
- Author
-
Eduard Prat, Sven Reiche, and Simona Bettoni
- Subjects
Physics ,Nuclear and High Energy Physics ,010308 nuclear & particles physics ,business.industry ,Free-electron laser ,Undulator ,Betatron ,01 natural sciences ,Transverse plane ,Tilt (optics) ,Optics ,Beamline ,0103 physical sciences ,Physics::Atomic and Molecular Clusters ,Physics::Accelerator Physics ,010306 general physics ,business ,Quadrupole magnet ,Instrumentation ,Beam (structure) - Abstract
A transverse tilt of the electron beam is normally not wanted in X-ray free-electron-laser (XFEL) facilities, since in a typical undulator beamline with quadrupole magnets only the central part of the beam with negligibly small betatron oscillations will produce significant XFEL radiation. In this work we present special configurations for which a transverse tilt can actually be used to improve the XFEL performance. In particular, we show with numerical simulations how tilted electron beams can be employed to generate two-color XFEL pulses, ultra-large-bandwidth XFEL radiation, and high-power and short duration XFEL radiation. We present and assess different mechanisms to generate the transverse tilt, namely a transverse deflecting structure, transverse wakefields, and introducing dispersion to an energy-chirped beam.
- Published
- 2017
24. Outline of a dielectric laser acceleration experiment at SwissFEL
- Author
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J. McNeur, Micha Dehler, Sven Reiche, F. Frei, Simona Bettoni, Albert Romann, Eduard Prat, Marco Calvi, C. Ozkan Loch, Rasmus Ischebeck, Martin Kozák, and Peter Hommelhoff
- Subjects
Physics ,Nuclear and High Energy Physics ,010308 nuclear & particles physics ,business.industry ,Electron ,Dielectric ,Laser ,Chip ,01 natural sciences ,law.invention ,Acceleration ,Optics ,law ,0103 physical sciences ,Femtosecond ,Cathode ray ,Physics::Accelerator Physics ,010306 general physics ,business ,Instrumentation ,Beam (structure) - Abstract
The Accelerator on a Chip International Program (ACHIP), funded by the Gordon and Betty Moore Foundation for a 5 year period, pursues basic research and development for a super-compact accelerator on a chip, where the accelerating structure is a dielectric microstructure excited by femtosecond laser pulses. The Paul Scherrer Institute (PSI) will contribute to this by providing the international collaboration access to the high-brightness electron beams in SwissFEL, where we plan to do a proof-of-principle demonstration of the acceleration of a highly relativistic beam. In this contribution we present the conceptual layout of the experiment, in which we will focus the beam down to sub-micrometer beam sizes. Start-to-end simulation results of the tracked electron beam, and first calculations of the accelerating field of the microstructure will be shown.
- Published
- 2017
25. Simple generation of two-color FEL pulses using a sextupole magnet
- Author
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Eduard Prat, Philipp Dijkstal, and Sven Reiche
- Subjects
Physics ,business.industry ,Free-electron laser ,Physics::Optics ,Undulator ,Sextupole magnet ,Tilt (optics) ,Optics ,Beamline ,Beam tilt ,Chirp ,Physics::Accelerator Physics ,business ,Beam (structure) - Abstract
We present a new and simple method to generate two-color free-electron laser (FEL) pulses. In our scheme an electron bunch is quadratically tilted in the transverse direction and exhibits an energy chirp. The head and tail of the bunch are aligned to the undulator beamline and will lase, while the middle part of the bunch undergoes orbit oscillations and thus is unable to amplify the FEL radiation. Since the beam is energy chirped, the central wavelengths of the SASE amplification at the two aligned parts of the bunch are different. The beam tilt is introduced by a variation of sextupole strength in a bunch compressor section. We present simulation results of this new method for the hard X-ray FEL beamline Aramis at SwissFEL. This includes the general performance and tunability of the scheme, the requirements on the energy chirp and tilt generation, and adverse effects associated with the beam tilt.
- Published
- 2019
26. Enhancing the concordance of two commercial dengue IgG ELISAs by exchange of the calibrator sample
- Author
-
Awadalkareem Adam, Sven Reiche, Tom Schüttoff, and Christian Jassoy
- Subjects
0301 basic medicine ,Adult ,Male ,Diagnostic methods ,Adolescent ,Concordance ,030106 microbiology ,Enzyme-Linked Immunosorbent Assay ,Antibodies, Viral ,Sensitivity and Specificity ,Dengue fever ,Dengue ,Sudan ,03 medical and health sciences ,Young Adult ,0302 clinical medicine ,Virology ,medicine ,Seroprevalence ,Humans ,Serologic Tests ,030212 general & internal medicine ,Igg elisa ,Child ,Aged ,Aged, 80 and over ,business.industry ,Infant ,Middle Aged ,medicine.disease ,Infectious Diseases ,Child, Preschool ,Immunoglobulin G ,Test performance ,Female ,business - Abstract
Background Dengue IgG testing is being recommended before dengue vaccination. Presently, the diagnostic method of choice is the dengue IgG ELISA. Objective Determine the test performance and concordance of two commercial dengue IgG ELISA kits. Study design A diagnostic study to examine the sensitivity, specificity, accuracy and concordance of the Panbio Dengue Indirect IgG ELISA kit and the NovaLisa Dengue IgG ELISA kit. Sera (483) were from dengue-endemic regions in Sudan. Test performance characteristics were determined when tests were performed as indicated in the test kits and when the Panbio calibrator sample was used for both tests. Results The sensitivity of the Panbio and the NovaLisa ELISA was 91.1% and 99.0% and the specificity was 79.4% and 50.9%. The Panbio test was slightly more accurate (87.5% compared with 84.0%). Quantitative measurement readings of the tests correlated. The calibrator samples gave different cutoff values. Replacing the NovaLisa cutoff sample with the Panbio calibrator sample raised the accuracy of the NovaLisa assay to 88% and increased the concordance of the tests from 82.8 to 93%. Conclusions The study shows that the two dengue IgG ELISAs differed clearly in sensitivity and specificity and gave discordant results for 17.2% of the sera. For the most part the discrepancy depended on the calibrator sample. The findings indicate that an optimized dengue IgG calibrator standard can enhance accuracy and concordance of commercial dengue ELISAs. An optimized standard calibrator would make dengue IgG seroprevalence testing more reliable.
- Published
- 2019
27. The SwissFEL soft X-ray free-electron laser beamline: Athos
- Author
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C. Gough, Ulrich Wagner, Adriano Zandonella, Nicole Hiller, Uwe Flechsig, Marco Pedrozzi, Thomas J. Schmidt, Eduard Prat, Simona Bettoni, Luc Patthey, Marco Calvi, Martin Paraliev, René Künzi, Thomas Lippuner, Christopher Arrell, Maik Kaiser, Predrag Ranitovic, Arturo Alarcon, Cigdem Ozkan Loch, Florian Löhl, Christoph Bostedt, Eugenio Ferrari, C. Svetina, Carlo Vicario, F. Frei, F. Marcellini, B. Keil, M. Bopp, Hans Jakob Wörner, Rafael Abela, Philipp Dijkstal, Martin Huppert, Gian Luca Orlandi, Sladana Dordevic, A. Trisorio, Colette Rosenberg, Romain Ganter, Rasmus Ischebeck, Bruce D. Patterson, Hans Heinrich Braun, Zheqiao Geng, J. Alex, Paolo Craievich, Thomas Schietinger, Claude Pradervand, Roger Kalt, Stephan Hunziker, Vladimir Arsov, Tine Celcer, Rolf Follath, Nazareno Gaiffi, Haimo Jöhri, Christoph Kittel, G. Marinkovic, S. Sanfilippo, Didier Voulot, Pavle Juranić, Andreas Dax, Kirsten Schnorr, and Sven Reiche
- Subjects
bandwidth ,Nuclear and High Energy Physics ,transverse-gradient ,design ,01 natural sciences ,law.invention ,Optics ,law ,generation ,0103 physical sciences ,chicane ,pulses ,010306 general physics ,Instrumentation ,Physics ,FEL ,Radiation ,010308 nuclear & particles physics ,business.industry ,Free-electron laser ,Optical physics ,Superradiance ,Undulator ,Laser ,Research Papers ,Beamline ,superradiance ,APPLE undulator ,Physics::Accelerator Physics ,business ,Ultrashort pulse ,Beam (structure) - Abstract
The SwissFEL soft X-ray free-electron laser (FEL) beamline Athos will be ready for user operation in 2021. Its design includes a novel layout of alternating magnetic chicanes and short undulator segments. Together with the APPLE X architecture of undulators, the Athos branch can be operated in different modes producing FEL beams with unique characteristics ranging from attosecond pulse length to high-power modes. Further space has been reserved for upgrades including modulators and an external seeding laser for better timing control. All of these schemes rely on state-of-the-art technologies described in this overview. The optical transport line distributing the FEL beam to the experimental stations was designed with the whole range of beam parameters in mind. Currently two experimental stations, one for condensed matter and quantum materials research and a second one for atomic, molecular and optical physics, chemical sciences and ultrafast single-particle imaging, are being laid out such that they can profit from the unique soft X-ray pulses produced in the Athos branch in an optimal way., Journal of Synchrotron Radiation, 26 (4), ISSN:0909-0495, ISSN:1600-5775
- Published
- 2018
28. Generation of ultra-large-bandwidth X-ray free-electron-laser pulses with a transverse-gradient undulator
- Author
-
Sven Reiche, Eduard Prat, and Marco Calvi
- Subjects
Physics ,Nuclear and High Energy Physics ,Radiation ,010308 nuclear & particles physics ,business.industry ,Broad bandwidth ,Bandwidth (signal processing) ,Free-electron laser ,X-ray ,ultra-large-bandwith X-ray pulses ,Undulator ,Research Papers ,01 natural sciences ,transverse-gradient undulator ,Transverse plane ,Optics ,free-electron laser ,Beam tilt ,0103 physical sciences ,Physics::Accelerator Physics ,simulations ,010306 general physics ,business ,Instrumentation - Abstract
A novel, flexible yet simple method to generate gigawatt X-ray free-electron-laser radiation with unprecedented spectral bandwidth above the 10% level is presented. Such broadband radiation will improve substantially the efficiency of techniques like X-ray crystallography and spectroscopy, paving the way for outstanding progress in fields like biology and material science., A new and simple method to generate X-ray free-electron-laser radiation with unprecedented spectral bandwidth above the 10% level is presented. The broad bandwidth is achieved by sending a transversely tilted beam through a transverse-gradient undulator. The extent of the bandwidth can easily be controlled by variation of the beam tilt or the undulator gradient. Numerical simulations confirm the validity and feasibility of this method.
- Published
- 2016
29. Generation and characterization of monoclonal antibodies specific for the Pseudorabies Virus nuclear egress complex
- Author
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Barbara G. Klupp, Thomas C. Mettenleiter, Julia E. Hölper, Sven Reiche, and Kati Franzke
- Subjects
Cancer Research ,Nuclear Envelope ,medicine.drug_class ,Viral protein ,viruses ,Immunoelectron microscopy ,Pseudorabies ,Biology ,Monoclonal antibody ,medicine.disease_cause ,Virus ,Cell Line ,Membrane bending ,Mice ,Viral Proteins ,03 medical and health sciences ,Virology ,medicine ,Animals ,Inner membrane ,Microscopy, Immunoelectron ,Nucleocapsid ,Virus Release ,030304 developmental biology ,Mice, Inbred BALB C ,0303 health sciences ,030306 microbiology ,Antibodies, Monoclonal ,biology.organism_classification ,Herpesvirus 1, Suid ,digestive system diseases ,Cell biology ,Infectious Diseases ,Cytoplasm ,Female ,Rabbits - Abstract
During herpesvirus replication, newly synthesized nucleocapsids exit the nucleus by a vesicle-mediated transport, which requires the nuclear egress complex (NEC), composed of the conserved viral proteins designated as pUL31 and pUL34 in the alphaherpesviruses pseudorabies virus (PrV) and herpes simplex viruses. Oligomerization of the heterodimeric NEC at the inner nuclear membrane (INM) results in membrane bending and budding of virus particles into the perinuclear space. The INM-derived primary envelope then fuses with the outer nuclear membrane to release nucleocapsids into the cytoplasm. The two NEC components are necessary and sufficient for induction of vesicle budding and scission as shown after co-expression in eukaryotic cells or in synthetic membranes. However, where and when the NEC is formed, how membrane curvature is mediated and how it is regulated, remains unclear. While monospecific antisera raised against the different components of the PrV NEC aided in the characterization and intracellular localization of the individual proteins, no NEC specific tools have been described yet for any herpesvirus. To gain more insight into vesicle budding and scission, we aimed at generating NEC specific monoclonal antibodies (mAbs). To this end, mice were immunized with bacterially expressed soluble PrV NEC, which was previously used for structure determination. Besides pUL31- and pUL34-specific mAbs, we also identified mAbs, which reacted only in the presence of both proteins indicating specificity for the complex. Confocal microscopy with those NEC-specific mAbs revealed small puncta (approx. 0.064 μm2) along the nuclear rim in PrV wild type infected cells. In contrast, ca. 5-fold larger speckles (approx. 0.35 μm2) were detectable in cells infected with a PrV mutant lacking the viral protein kinase pUS3, which is known to accumulate primary enveloped virions in the PNS within large invaginations of the INM, or in cells co-expressing pUL31 and pUL34. Kinetic experiments showed that while the individual proteins were detectable already between 2–4 hours after infection, the NEC-specific mAbs produced significant staining only after 4–6 hours in accordance with timing of nuclear egress. Taken together, the data indicate that these mAbs specifically label the PrV NEC.
- Published
- 2020
30. Characterization of the Electron Beam in the ACHIP Chamber in SwissFEL
- Author
-
Gian Luca Orlandi, Vitaliy A. Guzenko, Sven Reiche, Orell R. Hürzeler, Benedikt Hermann, Simona Borrelli, Christoph Kittel, Dominique Hauenstein, Eugenio Ferrari, Rasmus Ischebeck, Didier Voulot, Philipp Dijkstal, Dominique Zehnder, Simona Bettoni, Leonid Rivkin, Csaba Lombosi, Eduard Prat, and Marco Calvi
- Subjects
History ,Materials science ,Physics::Instrumentation and Detectors ,business.industry ,Electron ,Dielectric ,Computer Science Applications ,Education ,Characterization (materials science) ,Beam size ,Acceleration ,Optics ,Cathode ray ,Physics::Accelerator Physics ,Particle ,business ,Beam (structure) - Abstract
We have installed an interaction chamber in the electron beam line of SwissFEL. Electrons with a particle energy of 3 GeV are focused to a few-micrometer beam size. Samples placed in this beam can be aligned to the electron beam with a hexapod. The goal of this installation is to demonstrate laser-driven acceleration inside dielectric structures. We present here the layout of this interaction chamber as well as first measurements with the electron beam.
- Published
- 2020
31. Technical and Anatomical Considerations for Reproducible Inactivation of Large Animal Carcasses by Steam Sterilization
- Author
-
Sven Reiche, Benjamin Bartram-Sitzius, Ute Pfitzner, Jan Schinköthe, and Jens-Peter Teifke
- Subjects
0303 health sciences ,03 medical and health sciences ,Waste management ,030306 microbiology ,Health, Toxicology and Mutagenesis ,Public Health, Environmental and Occupational Health ,Environmental science ,Management, Monitoring, Policy and Law ,Steam sterilization ,030304 developmental biology ,Biotechnology ,Large animal - Abstract
Introduction: The complete inactivation of infectious tissues of large animal carcasses is one of the most challenging tasks in high-containment facilities. Steam sterilization is a method frequently in use to achieve biological inactivation of liquid and solid waste. Objective: This study aims to highlight parameters most effective in creating reproducible cycles for steam sterilization of pig and calf carcasses. Methods: Two pigs or 1 calf were sterilized by running a liquid cycle (n = 3) at 121°C for at least 120 minutes in a pass-through autoclave. To assess the physical and biological parameters, temperature data loggers and biological indicators (BIs) with spores of Geobacillus stearothermophilus (ATCC 7953) were placed at defined positions within animal carcasses. After completion of each cycle, data loggers were analyzed and BIs were incubated for 7 days at 60°C. Results: Initial testing with an undissected pig carcass resulted in suboptimal temperatures at the tissue level with growth on 1 BI. After modifications of the used stainless-steel boxes and by placing the reference probe of the autoclave in the animal carcass, reproducible cycles could be created. A complete inactivation of BIs and a temperature profile of >121°C for at least 20 minutes could be achieved in almost all probed tissues. Conclusion: Only minor modifications in carcass preparation and the used sterilization equipment resulted in effective and reproducible cycles to inactivate large animal carcasses by using a steam autoclave.
- Published
- 2020
32. Applications and Limits of Time-to-Energy Mapping of Protein Crystal Diffraction Using Energy-Chirped Polychromatic XFEL Pulses
- Author
-
Jasper J. van Thor, Karol Nass, Alisia Fadini, and Sven Reiche
- Subjects
Diffraction ,Physics::Optics ,02 engineering and technology ,lcsh:Technology ,01 natural sciences ,lcsh:Chemistry ,Optics ,0103 physical sciences ,Dispersion (optics) ,Chirp ,General Materials Science ,010306 general physics ,lcsh:QH301-705.5 ,Instrumentation ,Fluid Flow and Transfer Processes ,Physics ,lcsh:T ,business.industry ,XFEL ,Process Chemistry and Technology ,Resolution (electron density) ,General Engineering ,Free-electron laser ,Laue crystallography ,021001 nanoscience & nanotechnology ,lcsh:QC1-999 ,Computer Science Applications ,Pulse (physics) ,ultrafast dynamics ,lcsh:Biology (General) ,lcsh:QD1-999 ,lcsh:TA1-2040 ,Femtosecond ,lcsh:Engineering (General). Civil engineering (General) ,0210 nano-technology ,business ,Ultrashort pulse ,lcsh:Physics - Abstract
A broadband energy-chirped hard X-ray pulse has been demonstrated at the SwissFEL (free electron laser) with up to 4% bandwidth. We consider the characteristic parameters for analyzing the time dependence of stationary protein diffraction with energy-chirped pulses. Depending on crystal mosaic spread, convergence, and recordable resolution, individual reflections are expected to spend at least &asymp, 50 attoseconds and up to &asymp, 8 femtoseconds in reflecting condition. Using parameters for a chirped XFEL pulse obtained from simulations of 4% bandwidth conditions, ray-tracing simulations have been carried out to demonstrate the temporal streaking across individual reflections and resolution ranges for protein crystal diffraction. Simulations performed at a higher chirp (10%) emphasize the importance of chirp magnitude that would allow increased observation statistics for the temporal separation of individual reflections for merging and structure determination. Finally, we consider the fundamental limitation for obtaining time-dependent observations using chirped pulse diffraction. We consider the maximum theoretical time resolution achievable to be on the order of 50&ndash, 200 as from the instantaneous bandwidth of the chirped SASE pulse. We then assess the ability to propagate ultrafast optical pulses for pump-probe cross-correlation under characteristic conditions of material dispersion, in this regard, the limiting factors for time resolution scale with crystal thickness. Crystals that are below a few microns in size will be necessary for subfemtosecond time resolution.
- Published
- 2020
33. A simple and compact scheme to enhance the brightness of self-amplified spontaneous emission free-electron-lasers
- Author
-
Sven Reiche and Eduard Prat
- Subjects
Physics ,Nuclear and High Energy Physics ,Brightness ,Radiation ,Klystron ,business.industry ,Self-amplified spontaneous emission ,Free-electron laser ,02 engineering and technology ,Undulator ,021001 nanoscience & nanotechnology ,Laser ,01 natural sciences ,law.invention ,Optics ,Beamline ,law ,0103 physical sciences ,010306 general physics ,0210 nano-technology ,business ,Instrumentation ,Coherence (physics) - Abstract
A simple and compact scheme that enhances the brightness of self-amplified spontaneous-emission (SASE) free-electron lasers is presented. The method combines the high-brightness SASE scheme and the optical klystron concept to increase the temporal coherence of the produced radiation and to reduce the required length of the undulator beamline at the same time. The scheme is very simple and only requires compact chicanes between the modules of the undulator beamline. Simulations show that, in comparison with SASE, the brightness can be improved by up to a factor of ten and the required length to achieve saturation can be reduced by 20% or more.
- Published
- 2018
34. Development of monoclonal antibodies to Rift Valley Fever Virus and their application in antigen detection and indirect immunofluorescence
- Author
-
Claudia Mroz, Sven Reiche, Martin H. Groschup, Martin Eiden, and Kristina Maria Schmidt
- Subjects
0301 basic medicine ,Viral protein ,medicine.drug_class ,030106 microbiology ,Immunology ,Biology ,Viral Nonstructural Proteins ,medicine.disease_cause ,Monoclonal antibody ,Antibodies, Viral ,Virus ,03 medical and health sciences ,Antibodies, Monoclonal, Murine-Derived ,Mice ,Antigen ,Chlorocebus aethiops ,medicine ,Immunology and Allergy ,Animals ,Vector (molecular biology) ,Fluorescent Antibody Technique, Indirect ,Antigens, Viral ,Vero Cells ,chemistry.chemical_classification ,Mice, Inbred BALB C ,Rift Valley fever virus ,Virology ,030104 developmental biology ,chemistry ,Immunization ,Viral replication ,Glycoprotein - Abstract
Rift Valley fever virus is a mosquito-borne virus which is associated with acute hemorrhagic fever leading to large outbreaks among ruminants and humans in Africa and the Arabian Peninsula. RVFV circulates between mosquitoes, ruminants, camels and humans, which requires divergent amplification and maintenance strategies that have not been fully explored on the cellular and molecular level. We therefore assessed monoclonal antibodies for their applicability to monitor the expression pattern and kinetics of viral proteins in different RVFV infected cell species. Sequences of RVFV vaccine strain MP-12 were used in a bacterial expression system to produce recombinant non-structural proteins directed to NSs and NSm. After immunization of balb/c mice a set of monoclonal antibodies were generated and extensively characterized. The kinetics of RVFV proteins in vertebrate (Vero76) and mosquito-derived (C6/36) cells were evaluated with monoclonal antibodies against the nucleocapsid protein (NP) and the glycoproteins (Gn and Gc) as well as with the newly generated NSs and NSm derived monoclonal antibodies. Significant differences of viral protein distribution and accumulation in vertebrate compared to mosquito-derived cells could be demonstrated. Differences were observed for the nonstructural NSm and most intriguingly for the NSs protein indicating significant divergency of replication strategies of RVFV in Vero 76 cells and C6/36 cells. The described monoclonal antibodies are therefore powerful tools to elucidate the discrepancies of virus replication and interaction within the mammalian host compared to the mosquito vector.
- Published
- 2018
35. Dose rate produced by secondary radiation at the SwissFEL free electron laser facility
- Author
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Roland Lüscher, Sven Reiche, E. Hohmann, Thomas Schietinger, Albert Fuchs, Sabine Mayer, Romain Ganter, and Frederic Le Pimpec
- Subjects
Physics ,business.industry ,Nuclear engineering ,Monte Carlo method ,Free-electron laser ,General Medicine ,Electron ,Radiation ,Beamline ,Electromagnetic shielding ,Physics::Accelerator Physics ,Radiation protection ,business ,Simulation ,Leakage (electronics) - Abstract
A new large-scale facility is currently in the design phase at the Paul Scherrer Institute. SwissFEL is foreseen to accelerate electrons up to an energy of 7 GeV with a pulsed time structure. Unavoidable interactions of the primary beam with beam line components create secondary radiation. The shielding of the accelerator vault has to reduce the radiation level for accessible areas in compliance with legal constraints. In addition, the position and layout of cable ducts and infrastructure shafts through the shielding of the accelerator tunnel have to be investigated from a radiation protection point of view. In this work, the dose rate distribution inside the accelerator vault has been evaluated for expected beam loss scenarios (normal and diagnostic mode of operation) based on Monte Carlo calculations. By means of the multi-particle transport code FLUKA, a simplified model has been defined and the results have been parameterized. From these, a dose rate evaluation has been extracted for different positions inside the accelerator tunnel. The results can be used to investigate the leakage of radiation through cable ducts and infrastructure shafts for different design layouts or modes of operation.
- Published
- 2014
36. Chondrogenic potential of human dermal fibroblasts in a contractile, soft, self-assembling, peptide hydrogel
- Author
-
Cristina Castells-Sala, Sven Reiche, Hans Jörg Meisel, Bianca M. Bussmann, Núria Marí-Buyé, and Carlos E. Semino
- Subjects
0301 basic medicine ,biology ,Chemistry ,Cartilage ,Biomedical Engineering ,Medicine (miscellaneous) ,Chondrogenesis ,In vitro ,Cell biology ,Biomaterials ,Glycosaminoglycan ,03 medical and health sciences ,030104 developmental biology ,medicine.anatomical_structure ,Proteoglycan ,Tissue engineering ,medicine ,biology.protein ,Aggrecan ,Self-assembling peptide ,Biomedical engineering - Abstract
The present paper describes a simple approach to obtain three-dimensional (3D) cartilage constructs using human normal dermal fibroblasts (hNDFs) cultured in a self-assembling peptide nanofibre scaffold. During the first days of culture, the 3D constructs underwent morphological changes consisting of a substantial contraction process that ended in a small compact structure. During this process the system became sensitive to induction with standard chondrogenic medium, evidenced by the expression of specific markers of mature cartilage. First, it was detected that the samples become highly stained with toluidine blue dye over time (40-50 days), indicating that the system produced significantly high amounts of glycosaminoglycans. By quantitative PCR, it was confirmed that the system significantly upregulated the expression of the proteoglycan aggrecan, a good indicator of cartilage commitment. Moreover, collagen type II was upregulated at protein level, confirming that the system differentiated to a chondrocyte-like construct. Additionally, during the first days of culture in control medium analysed hNDFs proliferation capacity in this 3D system was analysed. This platform could be used in the future to obtain an autologous source of cells from a simple patient skin biopsy, which could be easily translated into a low-cost and effective regenerative therapy.
- Published
- 2013
37. rf traveling-wave electron gun for photoinjectors
- Author
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Riccardo Zennaro, M. Schaer, A. Citterio, Paolo Craievich, L. Stingelin, and Sven Reiche
- Subjects
Physics ,Nuclear and High Energy Physics ,Physics and Astronomy (miscellaneous) ,010308 nuclear & particles physics ,business.industry ,Surfaces and Interfaces ,01 natural sciences ,Optics ,0103 physical sciences ,Traveling wave ,lcsh:QC770-798 ,Physics::Accelerator Physics ,lcsh:Nuclear and particle physics. Atomic energy. Radioactivity ,010306 general physics ,business ,Joint (geology) ,Beam (structure) ,Electron gun - Abstract
The design of a photoinjector, in particular that of the electron source, is of central importance for free electron laser (FEL) machines where a high beam brightness is required. In comparison to standard designs, an rf traveling-wave photocathode gun can provide a more rigid beam with a higher brightness and a shorter pulse. This is illustrated by applying a specific optimization procedure to the SwissFEL photoinjector, for which a brightness improvement up to a factor 3 could be achieved together with a double gun output energy compared to the reference setup foreseeing a state-of-the-art S-band rf standing-wave gun. The higher brightness is mainly given by a (at least) double peak current at the exit of the gun which brings benefits for both the beam dynamics in the linac and the efficiency of the FEL process. The gun design foresees an innovative coaxial rf coupling at both ends of the structure which allows a solenoid with integrated bucking coil to be placed around the cathode in order to provide the necessary focusing right after emission.
- Published
- 2016
38. Two-color beam generation based on wakefield excitation
- Author
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Simona Bettoni, Eduard Prat, and Sven Reiche
- Subjects
Physics ,Nuclear and High Energy Physics ,Range (particle radiation) ,Beam diameter ,Physics and Astronomy (miscellaneous) ,010308 nuclear & particles physics ,business.industry ,Free-electron laser ,Surfaces and Interfaces ,Radiation ,01 natural sciences ,Optics ,0103 physical sciences ,Cathode ray ,lcsh:QC770-798 ,Physics::Accelerator Physics ,lcsh:Nuclear and particle physics. Atomic energy. Radioactivity ,Laser beam quality ,010306 general physics ,business ,Excitation ,Beam (structure) - Abstract
Several beam manipulation methods have been studied and experimentally tested to generate two-color photon beams in free electron laser facilities to accommodate the user requests. We propose to use the interaction of the beam with an oscillating longitudinal wakefield source to obtain a suitable electron beam structure. The bunch generates two subpulses with different energies and delayed in time passing through a magnetic chicane after its longitudinal phase space has been modulated by the wakefield source. According to this approach the power of the emitted radiation is not degraded compared to the monochromatic beam, and the setup in the machine is quite simple because the bunch is manipulated only in the high energy section, where it is more rigid. We present the design applied to SwissFEL. We identified the parameters and the corresponding range of tunability of the time and energy separation among the two subbunches.
- Published
- 2016
39. The physics of x-ray free-electron lasers
- Author
-
Agostino Marinelli, Claudio Pellegrini, and Sven Reiche
- Subjects
Free electron model ,Physics ,010308 nuclear & particles physics ,X-ray ,Theoretical models ,General Physics and Astronomy ,Laser ,01 natural sciences ,Electromagnetic radiation ,Charged particle ,Computational physics ,Magnetic field ,law.invention ,law ,0103 physical sciences ,010306 general physics ,Coherence (physics) - Abstract
The advent of x-ray free electron lasers has made possible the study of matter at the characteristic space and time scales of atomic and molecular phenomena using intense coherent x-ray pulses. This article describes the physical principles and the theoretical models governing the interaction of charged particles, electromagnetic waves, and external magnetic fields that comprise the x-ray free-electron lasers. It also includes a discussion of existing facilities and avenues for increasing the peak power and improving the control of spectral and coherence properties to allow the exploration of an even larger range of phenomena.\hskip-0.22em
- Published
- 2016
40. Undulator beamline optimization with integrated chicanes for X-ray free-electron-laser facilities
- Author
-
Romain Ganter, Thomas Schietinger, Eduard Prat, Marco Calvi, Sven Reiche, and Thomas J. Schmidt
- Subjects
Physics ,Nuclear and High Energy Physics ,Radiation ,010308 nuclear & particles physics ,business.industry ,Free-electron laser ,Undulator ,01 natural sciences ,Optics ,Beamline ,0103 physical sciences ,010306 general physics ,business ,Instrumentation ,Coherence (physics) - Abstract
An optimization of the undulator layout of X-ray free-electron-laser (FEL) facilities based on placing small chicanes between the undulator modules is presented. The installation of magnetic chicanes offers the following benefits with respect to state-of-the-art FEL facilities: reduction of the required undulator length to achieve FEL saturation, improvement of the longitudinal coherence of the FEL pulses, and the ability to produce shorter FEL pulses with higher power levels. Numerical simulations performed for the soft X-ray beamline of the SwissFEL facility show that optimizing the advantages of the layout requires shorter undulator modules than the standard ones. This proposal allows a very compact undulator beamline that produces fully coherent FEL pulses and it makes possible new kinds of experiments that require very short and high-power FEL pulses.
- Published
- 2016
41. Two-color operation of a free-electron laser with a tilted beam
- Author
-
Eduard Prat and Sven Reiche
- Subjects
Physics ,Nuclear and High Energy Physics ,Beam diameter ,Radiation ,business.industry ,Free-electron laser ,02 engineering and technology ,Undulator ,Photon energy ,021001 nanoscience & nanotechnology ,Laser ,01 natural sciences ,Beam parameter product ,law.invention ,Optics ,Beamline ,law ,0103 physical sciences ,Physics::Accelerator Physics ,Laser beam quality ,010306 general physics ,0210 nano-technology ,business ,Instrumentation - Abstract
With the successful operation of free-electron lasers (FELs) as user facilities there has been a growing demand for experiments with two photon pulses with variable photon energy and time separation. A configuration of an undulator with variable-gap control and a delaying chicane in the middle of the beamline is proposed. An injected electron beam with a transverse tilt will only yield FEL radiation for the parts which are close to the undulator axis. This allows, after re-aligning and delaying the electron beam, a different part of the bunch to be used to produce a second FEL pulse. This method offers independent control in photon energy and delay. For the parameters of the soft X-ray beamline Athos at the SwissFEL facility the photon energy tuning range is a factor of five with an adjustable delay between the two pulses from −50 to 950 fs.
- Published
- 2016
42. Physical Optics Simulations with PHASE for SwissFEL Beamlines
- Author
-
R. Follath, J. Bahrdt, U. Flechsig, and Sven Reiche
- Subjects
Ray tracing (physics) ,Diffraction ,Physics ,Optics ,Beamline ,business.industry ,Fourier optics ,Free-electron laser ,Stationary phase approximation ,Physical optics ,business ,Photons LK II ,Swiss Light Source - Abstract
PHASE is a software tool for physical optics simulation based on the stationary phase approximation method. The code is under continuous development since about 20 years and has been used for instance for fundamental studies and ray tracing of various beamlines at the Swiss Light Source. Along with the planning for SwissFEL a new hard X ray free electron laser under construction, new features have been added to permit practical performance predictions including diffraction effects which emerge with the fully coherent source. We present the application of the package on the example of the ARAMIS 1 beamline at SwissFEL. The X ray pulse calculated with GENESIS and given as an electrical field distribution has been propagated through the beamline to the sample position.We demonstrate the new features of PHASE like the treatment of measured figure errors, apertures and coatings of the mirrors and the application of Fourier optics propagators for free space propagation
- Published
- 2016
43. Ultrafast phenomena at the nanoscale: Novel science opportunities at the swissfel X-ray laser
- Author
-
Rafael Abela, M. van Daalen, Bill Pedrini, Romain Ganter, Sven Reiche, Marco Pedrozzi, Hans-Heinrich Braun, and Bruce D. Patterson
- Subjects
Diffraction ,Materials science ,Nanostructure ,business.industry ,Orders of magnitude (temperature) ,Resolution (electron density) ,Free-electron laser ,General Physics and Astronomy ,Nanotechnology ,Laser ,Synchrotron ,law.invention ,X-ray laser ,Optics ,law ,Femtosecond ,Optoelectronics ,business ,Ultrashort pulse - Abstract
Next-generation X-ray sources, based on the X-ray Free Electron Laser (XFEL) concept, will provide highly coherent, ultrashort pulses of soft and hard X-rays with peak intensity many orders of magnitude above that of a synchrotron. These pulses will allow studies of femtosecond dynamics at nanometer resolution and with chemical selectivity. They will produce coherent-diffraction images of organic and inorganic nanostructures without the deleterious effects of radiation damage.
- Published
- 2010
44. Loss of HIV-specific memory B-cells as a potential mechanism for the dysfunction of the humoral immune response against HIV
- Author
-
Ivanka Krznaric, Christian Jassoy, Bianca M. Bussmann, Bernhard Bieniek, Sven Reiche, and Frank Ackermann
- Subjects
Env ,HIV Infections ,HIV Antibodies ,Antibodies, Viral ,gag Gene Products, Human Immunodeficiency Virus ,Pathogenesis ,Immune system ,Antigen ,Immunity ,Virology ,Influenza, Human ,Tetanus Toxoid ,Humans ,Memory B cell ,Antibody ,Gag ,B-Lymphocytes ,biology ,env Gene Products, Human Immunodeficiency Virus ,Antibody titer ,HIV ,Antibodies, Bacterial ,Memory B-cell ,CD4 Lymphocyte Count ,Anti-Retroviral Agents ,B-cell Elispot ,Immunology ,Humoral immunity ,biology.protein ,Immunologic Memory - Abstract
A central, yet unresolved issue in the pathogenesis of HIV disease is the mechanism of antibody perturbation. In this study, HIV-specific memory B-cells were quantified in groups of infected subjects and compared with memory responses to other antigens and antibody titers. HIV-specific memory B-cell responses were vigorous in individuals with CD4(+) T-cell counts350/microl and weak or undetectable in subjects with CD4(+) T-cell numbers200/microl. Memory B-cell loss was permanent, because antiretroviral therapy failed to restore HIV-specific memory responses while influenza- and tetanus toxoid-specific memory B-cells remained unaffected or recovered. Antibody titers to Gag strongly correlated with memory B-cell frequencies. In contrast, Env-specific antibodies were maintained in advanced disease despite low or undetectable levels of memory B-cells. These results provide a potential mechanism by which destruction of HIV-specific CD4(+) T-cells affects the humoral immune response against HIV and compromises the ability to maintain an effective antibody response.
- Published
- 2010
- Full Text
- View/download PDF
45. Peptides from the SARS-associated coronavirus as tags for protein expression and purification
- Author
-
Christian Jassoy, Sven Reiche, Steffi Gruschke, and Bianca M. Bußmann
- Subjects
Protein tag ,Recombinant Fusion Proteins ,Blotting, Western ,Peptide ,Computational biology ,Biology ,medicine.disease_cause ,Peptide Mapping ,Article ,Chromatography, Affinity ,FLAG-tag ,Protein purification ,Escherichia coli ,medicine ,Coronavirus Nucleocapsid Proteins ,Coronavirus ,Tandem affinity purification ,chemistry.chemical_classification ,Antibodies, Monoclonal ,Nucleocapsid Proteins ,Fusion protein ,Molecular biology ,Immunoaffinity purification ,Severe acute respiratory syndrome-related coronavirus ,chemistry ,Electrophoresis, Polyacrylamide Gel ,Peptides ,Biotechnology ,Myc-tag - Abstract
Protein tagging with a peptide is a commonly used technique to facilitate protein detection and to carry out protein purification. Flexibility with respect to the peptide tag is essential since no single tag suites all purposes. This report describes the usage of two short peptides from the SARS-associated coronavirus nucleocapsid (SARS-N) protein as protein tags. Plasmids for the generation of tagged proteins were generated by ligating synthetic oligonucleotides for the peptide-coding regions downstream of the protein coding sequence. The data show recognition of prokaryotically expressed HIV-1 Gag/p24 fusion protein by Western blot and efficient affinity purification using monoclonal antibodies against the tags. The SARS peptide antibody system described presents an alternative tagging opportunity in the growing field of protein science.
- Published
- 2008
46. Development of ultra-short pulse, single coherent spike for SASE X-ray FELs
- Author
-
Claudio Pellegrini, James Rosenzweig, Sven Reiche, and Pietro Musumeci
- Subjects
Physics ,Nuclear and High Energy Physics ,business.industry ,Free-electron laser ,Pulse duration ,Electron ,Undulator ,Bunches ,Optics ,Cathode ray ,Physics::Accelerator Physics ,business ,Instrumentation ,Lasing threshold ,Coherence (physics) - Abstract
There is a large interest in the production of high power, ultra-short, 1 fs or less, coherent X-ray pulses, for atomic physics and other applications. However, the present design of X-ray SASE FELs leads to an X-ray pulse about 100 times longer. The time structure of the X-ray pulse is determined by several factors, mainly the electron bunch length and the FEL cooperation length. Until now all FELs have been working in the regime where the electron bunch length is much larger than the cooperation length. In the case of an X-ray SASE FEL this means that the X-ray pulse consists of a series of spikes, a few hundred in the case of the LCLS, and the bunch length is of the order of 200 fs. Several methods to reduce the bunch length to the 10 - 1 fs region have been proposed. These methods are based on electron bunch manipulation to cut the lasing part of the bunch to a fraction of the total length, thus reducing the X-ray pulse length. We are considering here a different method, using ultra-short, very low charge electron bunches, with a length of the order or shorter than the FEL cooperation length. In this case the X-ray pulse length after amplification in the undulator is a few times the electron bunch length. Our simulations show that in the case of LCLS and SPARX, operating with a 1 pC electron beam, we obtain X-ray pulses as short as 300 as, transform limited in the SPARX case, and almost transform limited in the LCLS case. Compared to other modes of producing short X-ray bunches this one offers the advantage of very small background signal, since all electrons are used to lase, and the charge is very small.
- Published
- 2008
47. Higher-order harmonics coupling in different free-electron laser codes
- Author
-
Sven Reiche, Luca Giannessi, Pietro Musumeci, and Henry P. Freund
- Subjects
Physics ,Coupling ,Nuclear and High Energy Physics ,Quantum mechanics ,Quantum electrodynamics ,Harmonics ,Harmonic ,Free-electron laser ,Electron ,Beam emittance ,Betatron ,Instrumentation ,Beam (structure) - Abstract
The capability for simulation of the dynamics of a free-electron laser including the higher-order harmonics in linear undulators exists in several existing codes as MEDUSA [H.P. Freund, S.G. Biedron, and S.V. Milton, IEEE J. Quantum Electron. 27 (2000) 243; H.P. Freund, Phys. Rev. ST-AB 8 (2005) 110701] and PERSEO [L. Giannessi, Overview of Perseo, a system for simulating FEL dynamics in Mathcad, 〈 http://www.jacow.org 〉, in: Proceedings of FEL 2006 Conference, BESSY, Berlin, Germany, 2006, p. 91], and has been recently implemented in GENESIS 1.3 [See 〈 http://www.perseo.enea.it 〉]. MEDUSA and GENESIS also include the dynamics of even harmonics induced by the coupling through the betatron motion. In addition MEDUSA, which is based on a non-wiggler averaged model, is capable of simulating the generation of even harmonics in the transversally cold beam regime, i.e. when the even harmonic coupling arises from non-linear effects associated with longitudinal particle dynamics and not to a finite beam emittance. In this paper a comparison between the predictions of the codes in different conditions is given.
- Published
- 2008
48. HIGH BRIGHTNESS BEAMS — APPLICATIONS TO FREE-ELECTRON LASERS
- Author
-
Sven Reiche
- Subjects
Physics ,Nuclear and High Energy Physics ,Brightness ,business.industry ,Astronomy and Astrophysics ,Electron ,Radiation ,Laser ,Beam parameter product ,Atomic and Molecular Physics, and Optics ,law.invention ,Optics ,law ,Cathode ray ,Optoelectronics ,Laser beam quality ,business ,Beam (structure) - Abstract
Free-Electron Lasers as high-brilliance radiation sources, rely on a high quality of the electron beam driving the FEL process. The amount of energy, transferred from the electrons to the radiation field, and thus the efficiency of the FEL depends on the provided beam parameters. The presentation discusses the impact of various beam parameter and how current designs of FEL injector try to accomplish the demands on the beam quality for reaching saturation.
- Published
- 2007
49. Design considerations for table-top, laser-based VUV and X-ray free electron lasers
- Author
-
M. Ferrario, B. van der Geer, Florian Grüner, Ulrich Schramm, T. Eichner, Sven Reiche, Matthias Fuchs, Stefan Becker, Luca Serafini, D. Habs, Hartmut Backe, R. Weingartner, Jürgen Meyer-ter-Vehn, Werner Lauth, and Michael Geissler
- Subjects
Accelerator Physics (physics.acc-ph) ,Free electron model ,Physics ,Energy loss ,Physics and Astronomy (miscellaneous) ,business.industry ,General Engineering ,X-ray ,FOS: Physical sciences ,FEL, laser acceleration, PACS 41.60.Cr ,General Physics and Astronomy ,Undulator ,Table (information) ,Laser ,law.invention ,Optics ,Light source ,52.38.Kd ,law ,Physics - Accelerator Physics ,business ,Beam (structure) - Abstract
A recent breakthrough in laser-plasma accelerators, based upon ultrashort high-intensity lasers, demonstrated the generation of quasi-monoenergetic GeV-electrons. With future Petawatt lasers ultra-high beam currents of ~100 kA in ~10 fs can be expected, allowing for drastic reduction in the undulator length of free-electron-lasers (FELs). We present a discussion of the key aspects of a table-top FEL design, including energy loss and chirps induced by space-charge and wakefields. These effects become important for an optimized table-top FEL operation. A first proof-of-principle VUV case is considered as well as a table-top X-ray-FEL which may open a brilliant light source also for new ways in clinical diagnostics., Comment: 6 pages, 4 figures; accepted for publication in Appl. Phys. B
- Published
- 2007
50. Simple Method to Generate Terawatt-Attosecond X-Ray Free-Electron-Laser Pulses
- Author
-
Eduard Prat and Sven Reiche
- Subjects
Physics ,business.industry ,Lasers ,X-Rays ,Attosecond ,Free-electron laser ,General Physics and Astronomy ,Context (language use) ,Electron ,Models, Theoretical ,Undulator ,Radiation ,Laser ,Linear particle accelerator ,law.invention ,Optics ,law ,Physics::Atomic and Molecular Clusters ,Physics::Accelerator Physics ,business - Abstract
X-ray free-electron lasers (XFELs) are cutting-edge research tools that produce almost fully coherent radiation with high power and short-pulse length with applications in multiple science fields. There is a strong demand to achieve even shorter pulses and higher radiation powers than the ones obtained at state-of-the-art XFEL facilities. In this context we propose a novel method to generate terawatt-attosecond XFEL pulses, where an XFEL pulse is pushed through several short good-beam regions of the electron bunch. In addition to the elements of conventional XFEL facilities, the method uses only a multiple-slotted foil and small electron delays between undulator sections. Our scheme is thus simple, compact, and easy to implement both in already operating as well as future XFEL projects. We present numerical simulations that confirm the feasibility and validity of our proposal.
- Published
- 2015
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