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Yeo, Yi Lin; Kirlangic, Mehmet Eylem; Heyder, Stefan; Supriyanto, Eko; Mohamad Salim, Maheza I.; Fiedler, Patrique; Haueisen, Jens
Linear versus quadratic detrending in analyzing simultaneous changes in DC-EEG and transcutaneous pCO2. - In: 2023 45th Annual International Conference of the IEEE Engineering in Medicine & Biology Conference (EMBC), (2023), insges. 4 S.

Physiological direct current (DC) potential shifts in electroencephalography (EEG) can be masked by artifacts such as slow electrode drifts. To reduce the influence of these artifacts, linear detrending has been proposed as a pre-processing step. We considered quadratic detrending, which has hardly been addressed for ultralow frequency components in EEG. We compared the performance of linear and quadratic detrending in simultaneously acquired DC-EEG and transcutaneous partial pressure of carbon dioxide during two activation methods: hyperventilation (HV) and apnea (AP). Quadratic detrending performed significantly better than linear detrending in HV, while for AP, our analysis was inconclusive with no statistical significance. We conclude that quadratic detrending should be considered for DC-EEG preprocessing.
Brockhaus, Elisabeth K.; Wolffram, Daniel; Stadler, Tanja; Osthege, Michael; Mitra, Tanmay; Littek, Jonas M.; Krymova, Ekaterina; Klesen, Anna J.; Huisman, Jana S.; Heyder, Stefan; Helleckes, Laura M.; Heiden, Matthias; Funk, Sebastian; Abbott, Sam; Bracher, Johannes
Why are different estimates of the effective reproductive number so different? : a case study on COVID-19 in Germany. - In: PLoS Computational Biology, ISSN 1553-7358, Bd. 19 (2023), 11, e1011653, S. 1-27

The effective reproductive number Rt has taken a central role in the scientific, political, and public discussion during the COVID-19 pandemic, with numerous real-time estimates of this quantity routinely published. Disagreement between estimates can be substantial and may lead to confusion among decision-makers and the general public. In this work, we compare different estimates of the national-level effective reproductive number of COVID-19 in Germany in 2020 and 2021. We consider the agreement between estimates from the same method but published at different time points (within-method agreement) as well as retrospective agreement across eight different approaches (between-method agreement). Concerning the former, estimates from some methods are very stable over time and hardly subject to revisions, while others display considerable fluctuations. To evaluate between-method agreement, we reproduce the estimates generated by different groups using a variety of statistical approaches, standardizing analytical choices to assess how they contribute to the observed disagreement. These analytical choices include the data source, data pre-processing, assumed generation time distribution, statistical tuning parameters, and various delay distributions. We find that in practice, these auxiliary choices in the estimation of Rt may affect results at least as strongly as the selection of the statistical approach. They should thus be communicated transparently along with the estimates.
Schima, Maximilian; Glock, Matthias; Berger, Frank; Köpf, Hendrik-Christian; Holbe, Stefan; Kaiser, Julian
Analysis of the influence of magnetic blowing field alignments on the DC switching arc :
Analyse des Einflusses magnetischer Blasfeldanordnungen auf den DC-Schaltlichtbogen. - In: Kontaktverhalten und Schalten, (2023), S. 51-60

Wolffram, Daniel; Abbott, Sam; An der Heiden, Matthias; Funk, Sebastian; Günther, Felix; Hailer, Davide; Heyder, Stefan; Hotz, Thomas; van de Kassteele, Jan; Küchenhoff, Helmut; Müller-Hansen, Sören; Syliqi, Diell̈e; Ullrich, Alexander; Weigert, Maximilian; Schienle, Melanie; Bracher, Johannes
Collaborative nowcasting of COVID-19 hospitalization incidences in Germany. - In: PLoS Computational Biology, ISSN 1553-7358, Bd. 19 (2023), 8, e1011394, S. 1-25

Real-time surveillance is a crucial element in the response to infectious disease outbreaks. However, the interpretation of incidence data is often hampered by delays occurring at various stages of data gathering and reporting. As a result, recent values are biased downward, which obscures current trends. Statistical nowcasting techniques can be employed to correct these biases, allowing for accurate characterization of recent developments and thus enhancing situational awareness. In this paper, we present a preregistered real-time assessment of eight nowcasting approaches, applied by independent research teams to German 7-day hospitalization incidences during the COVID-19 pandemic. This indicator played an important role in the management of the outbreak in Germany and was linked to levels of non-pharmaceutical interventions via certain thresholds. Due to its definition, in which hospitalization counts are aggregated by the date of case report rather than admission, German hospitalization incidences are particularly affected by delays and can take several weeks or months to fully stabilize. For this study, all methods were applied from 22 November 2021 to 29 April 2022, with probabilistic nowcasts produced each day for the current and 28 preceding days. Nowcasts at the national, state, and age-group levels were collected in the form of quantiles in a public repository and displayed in a dashboard. Moreover, a mean and a median ensemble nowcast were generated. We find that overall, the compared methods were able to remove a large part of the biases introduced by delays. Most participating teams underestimated the importance of very long delays, though, resulting in nowcasts with a slight downward bias. The accompanying prediction intervals were also too narrow for almost all methods. Averaged over all nowcast horizons, the best performance was achieved by a model using case incidences as a covariate and taking into account longer delays than the other approaches. For the most recent days, which are often considered the most relevant in practice, a mean ensemble of the submitted nowcasts performed best. We conclude by providing some lessons learned on the definition of nowcasting targets and practical challenges.
Sherratt, Katharine; Gruson, Hugo; Grah, Rok; Johnson, Helen; Niehus, Rene; Prasse, Bastian; Sandmann, Frank; Deuschel, Jannik; Wolffram, Daniel; Abbott, Sam; Ullrich, Alexander; Gibson, Graham; Ray, Evan L.; Reich, Nicholas G.; Sheldon, Daniel; Wang, Yijin; Wattanachit, Nutcha; Wang, Lijing; Trnka, Jan; Obozinski, Guillaume; Sun, Tao; Thanou, Dorina; Pottier, Loic; Krymova, Ekaterina; Meinke, Jan H.; Barbarossa, Maria Vittoria; Leithäuser, Neele; Mohring, Jan; Schneider, Johanna; Wlazło, Jarosław; Fuhrmann, Jan; Lange, Berit; Rodiah, Isti; Baccam, Prasith; Gurung, Heidi; Stage, Steven; Suchoski, Bradley; Budzinski, Jozef; Walraven, Robert; Villanueva, Inmaculada; Tucek, Vit; Smid, Martin; Zajíček, Milan; Pérez Álvarez, Cesar; Reina, Borja; Bosse, Nikos I.; Meakin, Sophie R.; Castro, Lauren; Fairchild, Geoffrey; Michaud, Isaac; Osthus, Dave; Alaimo Di Loro, Pierfrancesco; Maruotti, Antonello; Eclerová, Veronika; Kraus, Andrea; Kraus, David; Pribylova, Lenka; Dimitris, Bertsimas; Li, Michael Lingzhi; Saksham, Soni; Dehning, Jonas; Mohr, Sebastian; Priesemann, Viola; Redlarski, Grzegorz; Bejar Haro, Benjamin; Ardenghi, Giovanni; Parolini, Nicola; Ziarelli, Giovanni; Bock, Wolfgang; Heyder, Stefan; Hotz, Thomas; Singh, David E.; Guzman-Merino, Miguel; Aznarte, Jose L.; Moriña, David; Alonso, Sergio; Álvarez, Enric; López, Daniel; Prats, Clara; Burgard, Jan Pablo; Rodloff, Arne; Zimmermann, Tom; Kuhlmann, Alexander; Zibert, Janez; Pennoni, Fulvia; Divino, Fabio; Català, Marti; Lovison, Gianfranco; Giudici, Paolo; Tarantino, Barbara; Bartolucci, Francesco; Jona Lasinio, Giovanna; Mingione, Marco; Farcomeni, Alessio; Srivastava, Ajitesh; Montero-Manso, Pablo; Adiga, Aniruddha; Hurt, Benjamin; Lewis, Bryan; Marathe, Madhav; Porebski, Przemyslaw; Venkatramanan, Srinivasan; Bartczuk, Rafal P.; Dreger, Filip; Gambin, Anna; Gogolewski, Krzysztof; Gruziel-Słomka, Magdalena; Krupa, Bartosz; Moszyânski, Antoni; Niedzielewski, Karol; Nowosielski, Jedrzej; Radwan, Maciej; Rakowski, Franciszek; Semeniuk, Marcin; Szczurek, Ewa; Zieliânski, Jakub; Kisielewski, Jan; Pabjan, Barbara; Kirsten, Holger; Kheifetz, Yuri; Scholz, Markus; Biecek, Przemysław; Bodych, Marcin; Filinski, Maciej; Idzikowski, Radoslaw; Krueger, Tyll; Ozanski, Tomasz; Bracher, Johannes; Funk, Sebastian
Predictive performance of multi-model ensemble forecasts of COVID-19 across European nations. - In: eLife, ISSN 2050-084X, Bd. 12 (2023), e81916, S. 1-19
Großmann, Max; Bohm, Sebastian; Heyder, Stefan; Schwarzburg, Klaus; Kleinschmidt, Peter; Runge, Erich; Hannappel, Thomas
Generalized modeling of photoluminescence transients. - In: Physica status solidi, ISSN 1521-3951, Bd. 260 (2023), 1, 2200339, S. 1-12

Time-resolved photoluminescence (TRPL) measurements and the extraction of meaningful parameters involve four key ingredients: a suitable sample such as a semiconductor double heterostructure, a state-of-the-art measurement setup, a kinetic model appropriate for the description of the sample behavior, and a general analysis method to extract the model parameters of interest from the measured TRPL transients. Until now, the last ingredient is limited to single curve fits, which are mostly based on simple models and least-squares fits. These are often insufficient for the parameter extraction in real-world applications. The goal of this article is to give the community a universal method for the analysis of TRPL measurements, which accounts for the Poisson distribution of photon counting events. The method can be used to fit multiple TRPL transients simultaneously using general kinematic models, but should also be used for single transient fits. To demonstrate this approach, multiple TRPL transients of a GaAs/AlGaAs heterostructure are fitted simultaneously using coupled rate equations. It is shown that the simultaneous fits of several TRPL traces supplemented by systematic error estimations allow for a more meaningful and more robust parameter determination. The statistical methods also quantify the quality of the description by the underlying physical model.
Worthmann, Karl; Hotz, Thomas
Verbund: 05M2018 - KONSENS : Schlussbericht : Förderzeitraum: 01.01.2018-30.06.2021. - Ilmenau : Technische Universität Ilmenau. - 1 Online-Ressource (16 Seiten, 450,82 KB)Förderkennzeichen BMBF 05M18SIA
Burgold-Voigt, Sindy; Müller, Elke; Zopf, David; Monecke, Stefan; Braun, Sascha D.; Frankenfeld, Katrin; Kiehntopf, Michael; Weis, Sebastian; Schumacher, Thomas; Pletz, Mathias; Ehricht, Ralf
Development of a new antigen-based microarray platform for screening and detection of human IgG antibodies against SARS-CoV-2. - In: Scientific reports, ISSN 2045-2322, Bd. 12 (2022), 8067, S. 1-15
The CoNAN Study Group: Thomas Hotz, Petra Enders, Renate Koch, Steffen Mai, Matthias Ullrich, Cora Richert, Cornelius Eibner, Bettina Meinung, Kay Stötzer, Julia Köhler, Michael Kiehntopf, Hans Cipowicz, Christine Pinkwart, Hans Proquitté, Michael Bauer, Petra Dickmann, Annika Licht, Juliane Scholz, Wibke Wetzker, Anita Hartung, Daniel Weiß, Lara Thieme, Gabi Hanf, Clara Schnizer, Jasmin Müller, Jennifer Kosenkow, Franziska Röstel, Joel Guerra, Oliwia Makarewicz, Steffi Kolanos, Juliane Ankert, Stefan Hagel, Christina Bahrs, Nico Andreas, Raphaela Marquardt, Thomas Kamradt, Sabine Baumgart, Stefanie Deinhardt-Emmer, Sebastian Kuhn, Bettina Löffler, Michael Baier, Stefan Glöckner, André Scherag & Mathias W. Pletz

Strategies to contain the current SARS-CoV-2 pandemic rely, beside vaccinations, also on molecular and serological testing. For any kind of assay development, screening for the optimal antigen is essential. Here we describe the verification of a new protein microarray with different commercially available preparations significant antigens of SARS-CoV-2 that can be used for the evaluation of the performance of these antigens in serological assays and for antibody screening in serum samples. Antigens of other pathogens that are addressed by widely used vaccinations were also included. To evaluate the accuracy of 21 different antigens or antigen preparations on the microarray, receiver operating characteristics (ROC) curve analysis using ELISA results as reference were performed. Except for a single concentration, a diagnostic sensitivity of 1 was determined for all antigen preparations. A diagnostic specificity, as well as an area under the curve (AUC) of 1 was obtained for 16 of 21 antigen preparations. For the remaining five, the diagnostic specificity ranged from 0.942 to 0.981 and AUC from 0.974 to 0.999. The optimized assay was subsequently also applied to determine the immune status of previously tested individuals and/or to detect the immunization status after COVID-19 vaccination. Microarray evaluation of the antibody profiles of COVID-19 convalescent and post vaccination sera showed that the IgG response differed between these groups, and that the choice of the test antigen is crucial for the assay performance. Furthermore, the results showed that the immune response is highly individualized, depended on several factors (e.g., age or sex), and was not directly related to the severity of disease. The new protein microarray provides an ideal method for the parallel screening of many different antigens of vaccine-preventable diseases in a single sample and for reliable and meaningful diagnostic tests, as well as for the development of safe and specific vaccines.
Xie, Ting; Köhler, Michael; Heyder, Stefan; Günther, Mike; Cao-Riehmer, Jialan
Microfluidically-assisted isolation and characterization of Achromobacter spanius from soils for microbial degradation of synthetic polymers and organic solvents. - In: Environments, ISSN 2076-3298, Bd. 9 (2022), 12, 147, S. 1-17

A micro segmented-flow approach was utilized for the isolation soil bacteria that can degrade synthetic polymers as polyethylene glycols (PEG) and polyacrylamide (PAM). We had been able to obtain many strains; among them, five Achromobacter spanius strains from soil samples of specific sampling sites that were connected with ancient human impacts. In addition to the characterization of community responses and isolating single strains, this microfluidic approach allowed for investigation of the susceptibility of Achromobacter spanius strains against three synthetic polymers, including PEG, PAM, and Polyvinylpyrrolidone (PVP) and two organic solvents known as 1,4-dioxane and diglyme. The small stepwise variation of effector concentrations in 500 nL droplets provides a detailed reflection of the concentration-dependent response of bacterial growth and endogenous autofluorescence activity. As a result, all five strains can use PEG600 as carbon source. Furthermore, all strains showed similar dose-response characteristics in 1,4-dioxane and diglyme. However, significantly different PAM- and PVP-tolerances were found for these strains. Samples from the surface soil of prehistorical rampart areas supplied a strain capable of degradation of PEG, PVP, and PAM. This study demonstrates on the one hand, the potential of microsegment flow for miniaturized dose-response screening studies and its ability to detect novel strains, and on the other hand, two of five isolated Achromobacter spanius strains may be useful in providing optimal growth conditions in bioremediation and biodegradation processes.
Bracher, Johannes; Wolffram, Daniel; Deuschel, Jannik; Görgen, Konstantin; Ketterer, Jakob L.; Ullrich, Alexander; Abbott, Sam; Barbarossa, Maria Vittoria; Bertsimas, Dimitris; Bhatia, Sangeeta; Bodych, Marcin; Bosse, Nikos I.; Burgard, Jan Pablo; Castro, Lauren; Fairchild, Geoffrey; Fiedler, Jochen; Fuhrmann, Jan; Funk, Sebastian; Gambin, Anna; Gogolewski, Krzysztof; Heyder, Stefan; Hotz, Thomas; Kheifetz, Yuri; Kirsten, Holger; Krueger, Tyll; Krymova, Ekaterina; Leithäuser, Neele; Li, Michael L.; Meinke, Jan H.; Miasojedow, Błażej; Michaud, Isaac J.; Mohring, Jan; Nouvellet, Pierre; Nowosielski, Jedrzej M.; Ozanski, Tomasz; Radwan, Maciej; Rakowski, Franciszek; Scholz, Markus; Soni, Saksham; Srivastava, Ajitesh; Gneiting, Tilmann; Schienle, Melanie
National and subnational short-term forecasting of COVID-19 in Germany and Poland during early 2021. - In: Communications medicine, ISSN 2730-664X, Bd. 2 (2022), 136, S. 1-17

During the COVID-19 pandemic there has been a strong interest in forecasts of the short-term development of epidemiological indicators to inform decision makers. In this study we evaluate probabilistic real-time predictions of confirmed cases and deaths from COVID-19 in Germany and Poland for the period from January through April 2021.