A time-resolved proteomic and prognostic map of COVID-19

COVID-19 is highly variable in its clinical presentation, ranging from asymptomatic infection to severe organ damage and death. We characterized the time-dependent progression of the disease in 139 COVID-19 inpatients by measuring 86 accredited diagnostic parameters, such as blood cell counts and enzyme activities, as well as untargeted plasma proteomes at 687 sampling points. We report an initial spike in a systemic inflammatory response, which is gradually alleviated and followed by a protein signature indicative of tissue repair, metabolic reconstitution, and immunomodulation. We identify prognostic marker signatures for devising risk-adapted treatment strategies and use machine learning to classify therapeutic needs. We show that the machine learning models based on the proteome are transferable to an independent cohort. Our study presents a map linking routinely used clinical diagnostic parameters to plasma proteomes and their dynamics in an infectious disease

Feilke revisited : 60 Stellenbesuche

Weitere Hrsg.: Thorsten Pohl, Sara Rezat, Torsten Steinhoff, Martin SteinseiferAnlässlich des 60. Geburtstags des Linguisten und Sprachdidaktikers Helmuth Feilke wurden Wegbegleiterinnen und Wegbegleiter gebeten, einzelne Stellen in seinen wissenschaftlichen Schriften erneut zu besuchen. Entstanden sind pointierte Kommentare, kurze wissenschaftliche Abhandlungen und Analysen, Varianten auch des kritischen und kontroversen Nach- und Weiterdenkens und Ansätze zur Neu- oder Re-Kontextualisierung. Je nach wissenschaftlicher Vita der Autorinnen und Autoren kann es sich um Stellen handeln, deren Rezeption zeitlich weit zurückliegt, oder um Passagen, die ganz aktuelle Fragen der eigenen Forschungsarbeit tangieren. Abgesehen davon, dass ein kurzes Format für die Beiträge gewählt und die Autorinnen und Autoren gebeten wurden, die ausgewählte Stelle knapp zu verorten und zu erläutern, war die Bearbeitungsform gänzlich freigestellt. So sind Texte in einer Bandbreite von pointierten Kommentaren, kurzen wissenschaftlichen Abhandlungen und Analysen, Varianten des Nach- und Weiterdenkens, Ansätze zur Neu- oder Re-Kontextualisierung bis hin zu Formen des kritischen Hinterfragens und der kontroversen Auseinandersetzung entstanden

Intense, Directed Neutron Beams From A Laser-Driven Neutron Source At Phelix

Laser-driven neutrons are generated by the conversion of laser-accelerated ions via nuclear reactions inside a converter material. We present results from an experimental campaign at the PHELIX laser at GSI in Darmstadt where protons and deuterons were accelerated from thin deuterated plastic foils with thicknesses in the m and sub- m range. The neutrons were generated inside a sandwich-type beryllium converter, leading to reproducible neutron numbers around 1011 neutrons per shot. The angular distribution was measured with a high level of detail using up to 30 bubble detectors simultaneously. It shows a laser forward directed component of up to 1.42 x 1010 neutrons per steradian, corresponding to a dose of 43 mrem scaled to a distance of 1m from the converter.</p

Investigation of a laser-driven neutron source with respect to different fields of application

Due to their unique interaction with matter, neutrons are an interesting research and diagnostic instrument for various applications. To be able to utilize neutrons for the different applications, they have to be generated by nuclear reactions. This can for instance be done in accelerator-based spallation sources or fission reactors, which provide the possibility of generating high-flux neutron beams. However, they could be complemented by a novel and compact neutron source which is based on the conversion of laser-accelerated ions into neutrons inside a converter material, a so-called catcher. The angular distribution of the emitted neutrons is a superposition of an isotropic emission from generated compound nuclei in the catcher material and a forward directed neutron beam originating from special reactions such as pre-equilibrium emission and deuteron break-up. Neutrons from a laser-driven neutron source show an exponentially decaying energy spectrum with cut-off energies in the range of a few 10 MeV up to over 100 MeV. Nevertheless, for applications such as neutron resonance spectroscopy (NRS), neutrons in the epithermal energy range (0.1 eV - 100 keV) are preferable because many nuclei have distinct resonances in this regime. To maximize the neutron yield at epithermal energies, a moderating material is used to slow down the high-energy component of the neutron spectrum. The presented scientific thesis will focus on the applicability of a laser-based neutron source regarding established neutron applications in the high- and low-energy regime. In a first step, the for applications indispensable reproducability of such a source will be investigated. For that purpose, the neutron yield in the direction of the incoming ion's flight path (henceforth called "forward direction") will be increased and the total neutron yield will be measured for several shots. In a second step, the applicability of a laser-driven neutron source for neutron resonance spectroscopy on a static sample will be studied. As many elements have resonances in the epithermal region, the emitted neutron spectrum has to be moderated to increase the neutron flux in the desired energy range. Therefore, the study includes the analysis of the moderated neutron spectrum itself and its alteration after the NRS sample. The verification of reproducable neutron numbers and a detailed measurement of the angular distribution were conducted at the PHELIX laser (Petawatt High-Energy Laser for Heavy Ion EXperiments) at GSI Helmholtzzentrum für Schwerionenforschung GmbH in Darmstadt, Germany. The 200 J and 500 fs short-pulse laser beam was focused onto thin deuterated polymer foils with thicknesses between 400 and 1200 nm. During the experiment, intensities of the order of 10^20 W/cm^2 on target were achieved. The accelerated ions impinged a beryllium catcher yielding mean maximum neutron numbers of (5.25±0.77)·10^10 per shot. For a detailed measurement of the angular distribution, up to 30 bubble neutron dosimeters were used simultaneously. The result shows a forward pointing neutron beam with an opening angle of (100±2)° at full width half maximum. The highest measured neutron yield in the forward direction was (1.42±0.25)·10^10 neutrons per steradian which is an increase of 40% compared to the highest reported neutron numbers so far. The second key aspect of this thesis is the moderation of laser-driven neutrons and their subsequent application for a neutron resonance spectroscopy measurement on a static sample. This experiment was conducted at the Trident laser facility at Los Alamos National Laboratory (LANL), USA. The short-pulse configuration provides a maximum laser energy of 80 J on target within a pulse length of 500 fs, yielding maximum intensities above 10^20 W/cm^2. Ions were accelerated from thin polymer foils with thicknesses in the range of a few 100 nm. The catcher was surrounded by a block of high density polyethylene to slow down high-energy neutrons and thus maximize the epithermal yield. This could successfully be achieved by an increase of a factor 3 more neutrons in the energy range of the indium resonance compared to shots without a moderator. For the NRS measurement, a 5 mm indium sample was placed directly in front of the boron-doped microchannel plate (MCP) detector, which was used to measure the time of flight (ToF) transmission spectrum of the sample. The result of a single shot measurement shows a distinct resonance with a central energy of (1.61±0.19) eV and a width of (0.25±0.16) eV. These values are in good agreement with those of the indium resonance at 1.46 eV. During this experiment, we could sucessfully demonstrate a single shot neutron resonance spectroscopy measurement on a static sample. In summary, in the framework of the presented thesis it will be demonstrated, that a laser-driven neutron source satisfies the requirement of constantly high neutron fluxes, which is very important for significant and reliable measurements during applications. In addition, the effective moderation and the feasibility of laser-driven neutrons for neutron resonance spectroscopy on a static sample will be confirmed for the first time

Development of a Setup for Material Identification Based on Laser-Driven Neutron Resonance Spectroscopy

With the phasing out of many research reactors over the upcoming years, a shortcoming of small and medium sized neutron sources is to be expected. Laser-driven neutron sources have the potential to fill this void, with enormous progress being made in laser technology over the past years. Upcoming petawatt lasers with high repetition rates up to 10 Hz promise a tremendous increase in neutron flux. In this paper, a setup is developed and optimized to conduct neutron resonance spectroscopy at a laser-driven neutron source. This setup is then evaluated at an experimental campaign at the PHELIX laser system. Laser intensities up to 1021 W/cm² with a ns pre-pulse contrast of 10-7 were used for ion acceleration, resulting in (1.8±0.7)×108 N/sr per pulse corresponding to (2.3±1.0)×109 N in a 4 π equivalent. These pulses were moderated, collimated and investigated via the time of flight method in order to characterize the thermal neutron spectrum as well as the signal to noise ratio

Towards a Laser-driven polarized 3He Ion-Beam Source

In order to investigate the polarization degree of laser-accelerated 3He ions from a pre-polarized 3He gas-jet target, several challenges have to be overcome beforehand. One of these includes the demonstration of the feasibility of laser-induced ion acceleration out of gas-jet targets. In particular, the ion-emission angles as well as the ion-energy spectra have to be determined for future polarization measurements. Such an experiment was performed at the PHELIX Petawatt Laser Facility, GSI Darmstadt. As laser target, both 4He, and in a second step, unpolarized 3He gas were applied

Development of a Setup for Material Identification Based on Laser-Driven Neutron Resonance Spectroscopy

With the phasing out of many research reactors over the upcoming years, a shortcoming of small and medium sized neutron sources is to be expected. Laser-driven neutron sources have the potential to fill this void, with enormous progress being made in laser technology over the past years. Upcoming petawatt lasers with high repetition rates up to 10 Hz promise a tremendous increase in neutron flux. In this paper, a setup is developed and optimized to conduct neutron resonance spectroscopy at a laser-driven neutron source. This setup is then evaluated at an experimental campaign at the PHELIX laser system. Laser intensities up to 1021 W/cm² with a ns pre-pulse contrast of 10-7 were used for ion acceleration, resulting in (1.8±0.7)×108 N/sr per pulse corresponding to (2.3±1.0)×109 N in a 4 π equivalent. These pulses were moderated, collimated and investigated via the time of flight method in order to characterize the thermal neutron spectrum as well as the signal to noise ratio

Laser-induced acceleration of Helium ions from unpolarized gas jets

In order to develop a laser-driven spin-polarized 3He-ion beam source available for nuclear-physics experiments as well as for the investigation of polarized nuclear fusion, several challenges have to be overcome. Apart from the provision of a properly polarized 3He gas-jet target, one of the biggest milestones is the demonstration of the general feasibility of laser-induced ion acceleration out of gas-jet targets. Of particular importance is the knowledge about the main ion-emission angles as well as the achievable ion-energy spectra (dependent on the optimal set of laser and target parameters). We report on the results of such a feasibility study performed at PHELIX, GSI Darmstadt. Both 3He- and 4He-gas jets (n_gas ∼ 10^19 cm−3) were illuminated with high-intensity laser pulses, I_L ~ O(10^19 W cm^-2). The main ion-emission angles could be identified (±90° with respect to the laser-propagation direction) and the ion-energy spectra for all ion species could be extracted: for the optimal laser and target parameters, the high-energy cut-offs for He^2+,1+ ions were 4.65 MeV (with a normalized energy uncertainty of Delta E E^-1 = 0.033) and 3.27 MeV (Delta E E^-1 = 0.055), respectively

Demonstration of non-destructive and isotope-sensitive material analysis using a short-pulsed laser-driven epi-thermal neutron source

Neutrons are a valuable tool for non-destructive material investigation as their interaction cross sections with matter are isotope sensitive and can be used complementary to x-rays. So far, most neutron applications have been limited to large-scale facilities such as nuclear research reactors, spallation sources, and accelerator-driven neutron sources. Here we show the design and optimization of a laser-driven neutron source in the epi-thermal and thermal energy range, which is used for non-invasive material analysis. Neutron resonance spectroscopy, neutron radiography, and neutron resonance imaging with moderated neutrons are demonstrated for investigating samples in terms of isotope composition and thickness. The experimental results encourage applications in non-destructive and isotope-sensitive material analysis and pave the way for compact laser-driven neutron sources with high application potential