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Authors = Lothar Schäfer

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17 pages, 2309 KB  
Article
Monitoring the SARS-CoV-2 Pandemic: Prevalence of Antibodies in a Large, Repetitive Cross-Sectional Study of Blood Donors in Germany—Results from the SeBluCo Study 2020–2022
by Ruth Offergeld, Karina Preußel, Thomas Zeiler, Konstanze Aurich, Barbara I. Baumann-Baretti, Sandra Ciesek, Victor M. Corman, Viktoria Dienst, Christian Drosten, Siegfried Görg, Andreas Greinacher, Marica Grossegesse, Sebastian Haller, Hans-Gert Heuft, Natalie Hofmann, Peter A. Horn, Claudia Houareau, Ilay Gülec, Carlos Luis Jiménez Klingberg, David Juhl, Monika Lindemann, Silke Martin, Hannelore K. Neuhauser, Andreas Nitsche, Julia Ohme, Sven Peine, Ulrich J. Sachs, Lars Schaade, Richard Schäfer, Heinrich Scheiblauer, Martin Schlaud, Michael Schmidt, Markus Umhau, Tanja Vollmer, Franz F. Wagner, Lothar H. Wieler, Hendrik Wilking, Malte Ziemann, Marlow Zimmermann and Matthias an der Heidenadd Show full author list remove Hide full author list
Pathogens 2023, 12(4), 551; https://doi.org/10.3390/pathogens12040551 - 2 Apr 2023
Cited by 9 | Viewed by 9055
Abstract
SARS-CoV-2 serosurveillance is important to adapt infection control measures and estimate the degree of underreporting. Blood donor samples can be used as a proxy for the healthy adult population. In a repeated cross-sectional study from April 2020 to April 2021, September 2021, and [...] Read more.
SARS-CoV-2 serosurveillance is important to adapt infection control measures and estimate the degree of underreporting. Blood donor samples can be used as a proxy for the healthy adult population. In a repeated cross-sectional study from April 2020 to April 2021, September 2021, and April/May 2022, 13 blood establishments collected 134,510 anonymised specimens from blood donors in 28 study regions across Germany. These were tested for antibodies against the SARS-CoV-2 spike protein and nucleocapsid, including neutralising capacity. Seroprevalence was adjusted for test performance and sampling and weighted for demographic differences between the sample and the general population. Seroprevalence estimates were compared to notified COVID-19 cases. The overall adjusted SARS-CoV-2 seroprevalence remained below 2% until December 2020 and increased to 18.1% in April 2021, 89.4% in September 2021, and to 100% in April/May 2022. Neutralising capacity was found in 74% of all positive specimens until April 2021 and in 98% in April/May 2022. Our serosurveillance allowed for repeated estimations of underreporting from the early stage of the pandemic onwards. Underreporting ranged between factors 5.1 and 1.1 in the first two waves of the pandemic and remained well below 2 afterwards, indicating an adequate test strategy and notification system in Germany. Full article
(This article belongs to the Special Issue Transfusion-Transmissible Infections and Epidemiological Surveillance)
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15 pages, 6575 KB  
Article
Quasi-Static and Fatigue Properties of Thermoset Sandwiches with 3D Continuous Fibre Reinforced Polyurethane Foam Core
by Kay Schäfer, Daisy Nestler and Lothar Kroll
Materials 2022, 15(3), 764; https://doi.org/10.3390/ma15030764 - 20 Jan 2022
Cited by 7 | Viewed by 2672
Abstract
Innovative materials for substituting metals are required to reduce the mass of moving components. This decreases the CO2 emissions of overall systems. A thermoset sandwich for high mechanical properties and thermal insulation is presented in this paper. It has an innovative 3D [...] Read more.
Innovative materials for substituting metals are required to reduce the mass of moving components. This decreases the CO2 emissions of overall systems. A thermoset sandwich for high mechanical properties and thermal insulation is presented in this paper. It has an innovative 3D continuous reinforced core, which allows the optimisation of the substance exploitation by wide-ranging possibilities of fibre orientation. This was demonstrated with three sandwich variants. The reference had no core reinforcement and the other two were reinforced with different spacer fabrics. The process chain for the manufacturing consists of Structural Reaction Injection Moulding (SRIM) and Vacuum Assisted Resin Transfer Moulding (VARTM). Significant increases in absolute as well as specific characteristic values were demonstrated by the reinforcement in a compression and bending test. It was also shown that quasi-static characteristic values under fatigue loading are maintained to a greater extent with the core reinforcement. The sandwich material was applied as a floor assembly for a snow groomer. The design was tailor-made for the mechanical, thermal and acoustic requirements. This proved the transferability of the process chain for manufacturing samples to the production of large-volume components with complex geometry. Full article
(This article belongs to the Special Issue Performance Research of Polyurethane Foams and Composites)
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14 pages, 5038 KB  
Article
Numerical Studies of the Viscosity of Reacting Polyurethane Foam with Experimental Validation
by Kay Schäfer, Daisy Nestler, Jürgen Tröltzsch, Ikenna Ireka, Dariusz Niedziela, Konrad Steiner and Lothar Kroll
Polymers 2020, 12(1), 105; https://doi.org/10.3390/polym12010105 - 4 Jan 2020
Cited by 9 | Viewed by 4229
Abstract
Products made of polyurethane foam are manufactured by the chemical reaction of various low-viscosity raw materials and additives. The diversity of different formulations to meet the requirements of the market makes the characterization of their processing and flow properties important for a simple [...] Read more.
Products made of polyurethane foam are manufactured by the chemical reaction of various low-viscosity raw materials and additives. The diversity of different formulations to meet the requirements of the market makes the characterization of their processing and flow properties important for a simple and error-free production. The modeling and simulation of such processes are equally of great importance. This provides additional findings without the expense of real tests and makes it easier to design components. The work described in this paper was carried out against this background. An experimental setup using a rheometer was developed to determine the flow and curing properties of reacting polyurethane foam reproducibly with comparable expansion conditions to industrial processes. The experiment was mathematically modelled to investigate the rheology of reacting polyurethane foams. The mathematical framework consists of coupled, non-linear, partial differential equations for the dynamics and the heat transfer processes in the system. These are solved numerically in 3D using finite volume techniques under adequate physical conditions. The accuracy of two viscosity laws according to the state of the art and their novel combination were investigated in this context. The proposed viscosity model of this study provides accurate results compared to the experiment. Full article
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18 pages, 75 KB  
Article
Carl Gustav Jung, Quantum Physics and the Spiritual Mind: A Mystical Vision of the Twenty-First Century
by Diogo Valadas Ponte and Lothar Schäfer
Behav. Sci. 2013, 3(4), 601-618; https://doi.org/10.3390/bs3040601 - 13 Nov 2013
Cited by 18 | Viewed by 20497
Abstract
We describe similarities in the ontology of quantum physics and of Carl Gustav Jung’s psychology. In spite of the fact that physics and psychology are usually considered as unrelated, in the last century, both of these disciplines have led at the same time [...] Read more.
We describe similarities in the ontology of quantum physics and of Carl Gustav Jung’s psychology. In spite of the fact that physics and psychology are usually considered as unrelated, in the last century, both of these disciplines have led at the same time to revolutionary changes in the Western understanding of the cosmic order, discovering a non-empirical realm of the universe that doesn’t consist of material things but of forms. These forms are real, even though they are invisible, because they have the potential to appear in the empirical world and act in it. We present arguments that force us to believe, that the empirical world is an emanation out of a cosmic realm of potentiality, whose forms can appear as physical structures in the external world and as archetypal concepts in our mind. Accordingly, the evolution of life now appears no longer as a process of the adaptation of species to their environment, but as the adaptation of minds to increasingly complex forms that exist in the cosmic potentiality. The cosmic connection means that the human mind is a mystical mind. Full article
(This article belongs to the Special Issue Analytical Psychology: Theory and Practice)
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