TY - JOUR A1 - Stulpe, Werner T1 - Conditional Expectations, Conditional Distributions, and A Posteriori Ensembles in Generalized Probability Theory JF - International Journal of Theoretical Physics. 27 (1988), H. 5 Y1 - 1988 SN - 1572-9575 SP - 587 EP - 611 ER - TY - JOUR A1 - Janus, Kevin Alexander A1 - Achtsnicht, Stefan A1 - Drinic, Aleksander A1 - Kopp, Alexander A1 - Keusgen, Michael A1 - Schöning, Michael Josef T1 - Transient magnesium-based thin-film temperature sensor on a flexible, bioabsorbable substrate for future medical applications JF - Applied Research N2 - In this work, the bioabsorbable materials, namely fibroin, polylactide acid (PLA), magnesium and magnesium oxide are investigated for their application as transient, resistive temperature detectors (RTD). For this purpose, a thin-film magnesium-based meander-like electrode is deposited onto a flexible, bioabsorbable substrate (fibroin or PLA) and encapsulated (passivated) by additional magnesium oxide layers on top and below the magnesium-based electrode. The morphology of different layered RTDs is analyzed by scanning electron microscopy. The sensor performance and lifetime of the RTD is characterized both under ambient atmospheric conditions between 30°C and 43°C, and wet tissue-like conditions with a constant temperature regime of 37°C. The latter triggers the degradation process of the magnesium-based layers. The 3-layers RTDs on a PLA substrate could achieve a lifetime of 8.5 h. These sensors also show the best sensor performance under ambient atmospheric conditions with a mean sensitivity of 0.48 Ω/°C ± 0.01 Ω/°C. KW - Silk fibroin KW - Polylactide acid KW - Bioabsorbable KW - Resistive temperature detector Y1 - 2023 U6 - https://doi.org/10.1002/appl.202300102 SN - 2702-4288 (Print) N1 - Corresponding author: Michael Josef Schöning IS - Accepted manuscript PB - Wiley-VCH ER - TY - JOUR A1 - Janus, Kevin Alexander A1 - Achtsnicht, Stefan A1 - Tempel, Laura A1 - Drinic, Aleksaner A1 - Kopp, Alexander A1 - Keusgen, Michael A1 - Schöning, Michael Josef T1 - Influence of fibroin membrane composition and curing parameters on the performance of a biodegradable enzymatic biosensor manufactured from Silicon-Free Carbon JF - Physica status solidi : pss. A, Applications and materials science N2 - Herein, fibroin, polylactide (PLA), and carbon are investigated for their suitability as biocompatible and biodegradable materials for amperometric biosensors. For this purpose, screen-printed carbon electrodes on the biodegradable substrates fibroin and PLA are modified with a glucose oxidase membrane and then encapsulated with the biocompatible material Ecoflex. The influence of different curing parameters of the carbon electrodes on the resulting biosensor characteristics is studied. The morphology of the electrodes is investigated by scanning electron microscopy, and the biosensor performance is examined by amperometric measurements of glucose (0.5–10 mM) in phosphate buffer solution, pH 7.4, at an applied potential of 1.2 V versus a Ag/AgCl reference electrode. Instead of Ecoflex, fibroin, PLA, and wound adhesive are tested as alternative encapsulation compounds: a series of swelling tests with different fibroin compositions, PLA, and Ecoflex has been performed before characterizing the most promising candidates by chronoamperometry. Therefore, the carbon electrodes are completely covered with the particular encapsulation material. Chronoamperometric measurements with H2O2 concentrations between 0.5 and 10 mM enable studying the leakage current behavior. KW - amperometric biosensors KW - biocompatible KW - biodegradabl KW - encapsulation materials KW - fibroin Y1 - 2023 U6 - https://doi.org/10.1002/pssa.202300081 SN - 1862-6300 (Print) SN - 1862-6319 (Online) N1 - Corresponding author: Michael J. Schöning VL - 220 IS - 22 PB - Wiley-VCH CY - Weinheim ER - TY - JOUR A1 - Karschuck, Tobias A1 - Poghossian, Arshak A1 - Ser, Joey A1 - Tsokolakyan, Astghik A1 - Achtsnicht, Stefan A1 - Wagner, Patrick A1 - Schöning, Michael Josef T1 - Capacitive model of enzyme-modified field-effect biosensors: Impact of enzyme coverage JF - Sensors and Actuators B: Chemical N2 - Electrolyte-insulator-semiconductor capacitors (EISCAP) belong to field-effect sensors having an attractive transducer architecture for constructing various biochemical sensors. In this study, a capacitive model of enzyme-modified EISCAPs has been developed and the impact of the surface coverage of immobilized enzymes on its capacitance-voltage and constant-capacitance characteristics was studied theoretically and experimentally. The used multicell arrangement enables a multiplexed electrochemical characterization of up to sixteen EISCAPs. Different enzyme coverages have been achieved by means of parallel electrical connection of bare and enzyme-covered single EISCAPs in diverse combinations. As predicted by the model, with increasing the enzyme coverage, both the shift of capacitance-voltage curves and the amplitude of the constant-capacitance signal increase, resulting in an enhancement of analyte sensitivity of the EISCAP biosensor. In addition, the capability of the multicell arrangement with multi-enzyme covered EISCAPs for sequentially detecting multianalytes (penicillin and urea) utilizing the enzymes penicillinase and urease has been experimentally demonstrated and discussed. KW - Field-effect biosensor KW - Capacitive model KW - Enzyme coverage KW - Multianalyte detection KW - Penicillin Y1 - 2024 U6 - https://doi.org/10.1016/j.snb.2024.135530 SN - 0925-4005 (Print) SN - 1873-3077 (Online) N1 - Corresponding Author: Michael J. Schöning VL - 408 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Molinnus, Denise A1 - Janus, Kevin Alexander A1 - Fang, Anyelina C. A1 - Drinic, Aleksander A1 - Achtsnicht, Stefan A1 - Köpf, Marius A1 - Keusgen, Michael A1 - Schöning, Michael Josef T1 - Thick-film carbon electrode deposited onto a biodegradable fibroin substrate for biosensing applications JF - Physica status solidi (a) N2 - This study addresses a proof-of-concept experiment with a biocompatible screen-printed carbon electrode deposited onto a biocompatible and biodegradable substrate, which is made of fibroin, a protein derived from silk of the Bombyx mori silkworm. To demonstrate the sensor performance, the carbon electrode is functionalized as a glucose biosensor with the enzyme glucose oxidase and encapsulated with a silicone rubber to ensure biocompatibility of the contact wires. The carbon electrode is fabricated by means of thick-film technology including a curing step to solidify the carbon paste. The influence of the curing temperature and curing time on the electrode morphology is analyzed via scanning electron microscopy. The electrochemical characterization of the glucose biosensor is performed by amperometric/voltammetric measurements of different glucose concentrations in phosphate buffer. Herein, systematic studies at applied potentials from 500 to 1200 mV to the carbon working electrode (vs the Ag/AgCl reference electrode) allow to determine the optimal working potential. Additionally, the influence of the curing parameters on the glucose sensitivity is examined over a time period of up to 361 days. The sensor shows a negligible cross-sensitivity toward ascorbic acid, noradrenaline, and adrenaline. The developed biocompatible biosensor is highly promising for future in vivo and epidermal applications. KW - biocompatible materials KW - biodegradable electronic devices KW - biosensors KW - carbon electrodes KW - glucose Y1 - 2022 U6 - https://doi.org/10.1002/pssa.202200100 SN - 1862-6319 N1 - Corresponding author: Michael J. Schöning VL - 219 IS - 23 SP - 1 EP - 9 PB - Wiley-VCH CY - Weinheim ER - TY - JOUR A1 - Özsoylu, Dua A1 - Kizildag, Sefa A1 - Schöning, Michael Josef A1 - Wagner, Torsten T1 - Differential chemical imaging of extracellular acidification within microfluidic channels using a plasma-functionalized light-addressable potentiometric sensor (LAPS) JF - Physics in Medicine N2 - Extracellular acidification is a basic indicator for alterations in two vital metabolic pathways: glycolysis and cellular respiration. Measuring these alterations by monitoring extracellular acidification using cell-based biosensors such as LAPS plays an important role in studying these pathways whose disorders are associated with numerous diseases including cancer. However, the surface of the biosensors must be specially tailored to ensure high cell compatibility so that cells can represent more in vivo-like behavior, which is critical to gain more realistic in vitro results from the analyses, e.g., drug discovery experiments. In this work, O2 plasma patterning on the LAPS surface is studied to enhance surface features of the sensor chip, e.g., wettability and biofunctionality. The surface treated with O2 plasma for 30 s exhibits enhanced cytocompatibility for adherent CHO–K1 cells, which promotes cell spreading and proliferation. The plasma-modified LAPS chip is then integrated into a microfluidic system, which provides two identical channels to facilitate differential measurements of the extracellular acidification of CHO–K1 cells. To the best of our knowledge, it is the first time that extracellular acidification within microfluidic channels is quantitatively visualized as differential (bio-)chemical images. Y1 - 2020 U6 - https://doi.org/10.1016/j.phmed.2020.100030 SN - 2352-4510 VL - 10 IS - 100030 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Engelmann, Ulrich M. A1 - Pourshahidi, Mohammad Ali A1 - Shalaby, Ahmed A1 - Krause, Hans-Joachim T1 - Probing particle size dependency of frequency mixing magnetic detection with dynamic relaxation simulation JF - Journal of Magnetism and Magnetic Materials N2 - Biomedical applications of magnetic nanoparticles (MNP) fundamentally rely on the particles’ magnetic relaxation as a response to an alternating magnetic field. The magnetic relaxation complexly depends on the interplay of MNP magnetic and physical properties with the applied field parameters. It is commonly accepted that particle core size is a major contributor to signal generation in all the above applications, however, most MNP samples comprise broad distribution spanning nm and more. Therefore, precise knowledge of the exact contribution of individual core sizes to signal generation is desired for optimal MNP design generally for each application. Specifically, we present a magnetic relaxation simulation-driven analysis of experimental frequency mixing magnetic detection (FMMD) for biosensing to quantify the contributions of individual core size fractions towards signal generation. Applying our method to two different experimental MNP systems, we found the most dominant contributions from approx. 20 nm sized particles in the two independent MNP systems. Additional comparison between freely suspended and immobilized MNP also reveals insight in the MNP microstructure, allowing to use FMMD for MNP characterization, as well as to further fine-tune its applicability in biosensing. Y1 - 2022 U6 - https://doi.org/10.1016/j.jmmm.2022.169965 SN - 0304-8853 VL - 563 IS - In progress, Art. No. 169965 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Achtsnicht, Stefan A1 - Tödter, Julia A1 - Niehues, Julia A1 - Telöken, Matthias A1 - Offenhäusser, Andreas A1 - Krause, Hans-Joachim A1 - Schröper, Florian T1 - 3D printed modular immunofiltration columns for frequency mixing-based multiplex magnetic immunodetection JF - Sensors N2 - For performing point-of-care molecular diagnostics, magnetic immunoassays constitute a promising alternative to established enzyme-linked immunosorbent assays (ELISA) because they are fast, robust and sensitive. Simultaneous detection of multiple biomolecular targets from one body fluid sample is desired. The aim of this work is to show that multiplex magnetic immunodetection based on magnetic frequency mixing by means of modular immunofiltration columns prepared for different targets is feasible. By calculations of the magnetic response signal, the required spacing between the modules was determined. Immunofiltration columns were manufactured by 3D printing and antibody immobilization was performed in a batch approach. It was shown experimentally that two different target molecules in a sample solution could be individually detected in a single assaying step with magnetic measurements of the corresponding immobilization filters. The arrangement order of the filters and of a negative control did not influence the results. Thus, a simple and reliable approach to multi-target magnetic immunodetection was demonstrated. Y1 - 2019 U6 - https://doi.org/10.3390/s19010148 SN - 1424-8220 VL - 19 IS - 1 PB - MDPI CY - Basel ER - TY - JOUR A1 - Engelmann, Ulrich M. A1 - Shalaby, Ahmed A1 - Shasha, Carolyn A1 - Krishnan, Kannan M. A1 - Krause, Hans-Joachim T1 - Comparative modeling of frequency mixing measurements of magnetic nanoparticles using micromagnetic simulations and Langevin theory JF - Nanomaterials N2 - Dual frequency magnetic excitation of magnetic nanoparticles (MNP) enables enhanced biosensing applications. This was studied from an experimental and theoretical perspective: nonlinear sum-frequency components of MNP exposed to dual-frequency magnetic excitation were measured as a function of static magnetic offset field. The Langevin model in thermodynamic equilibrium was fitted to the experimental data to derive parameters of the lognormal core size distribution. These parameters were subsequently used as inputs for micromagnetic Monte-Carlo (MC)-simulations. From the hysteresis loops obtained from MC-simulations, sum-frequency components were numerically demodulated and compared with both experiment and Langevin model predictions. From the latter, we derived that approximately 90% of the frequency mixing magnetic response signal is generated by the largest 10% of MNP. We therefore suggest that small particles do not contribute to the frequency mixing signal, which is supported by MC-simulation results. Both theoretical approaches describe the experimental signal shapes well, but with notable differences between experiment and micromagnetic simulations. These deviations could result from Brownian relaxations which are, albeit experimentally inhibited, included in MC-simulation, or (yet unconsidered) cluster-effects of MNP, or inaccurately derived input for MC-simulations, because the largest particles dominate the experimental signal but concurrently do not fulfill the precondition of thermodynamic equilibrium required by Langevin theory. KW - Magnetic nanoparticles KW - Frequency mixing magnetic detection KW - Langevin theory KW - Micromagnetic simulation KW - Nonequilibrium dynamics Y1 - 2021 SN - 2079-4991 U6 - https://doi.org/10.3390/nano11051257 N1 - This article belongs to the Special Issue Applications and Properties of Magnetic Nanoparticles VL - 11 IS - 5 SP - 1 EP - 16 PB - MDPI CY - Basel ER - TY - JOUR A1 - Aliazizi, Fereshteh A1 - Özsoylu, Dua A1 - Bakhshi Sichani, Soroush A1 - Khorshid, Mehran A1 - Glorieux, Christ A1 - Robbens, Johan A1 - Schöning, Michael Josef A1 - Wagner, Patrick T1 - Development and Calibration of a Microfluidic, Chip-Based Sensor System for Monitoring the Physical Properties of Water Samples in Aquacultures JF - Micromachines N2 - In this work, we present a compact, bifunctional chip-based sensor setup that measures the temperature and electrical conductivity of water samples, including specimens from rivers and channels, aquaculture, and the Atlantic Ocean. For conductivity measurements, we utilize the impedance amplitude recorded via interdigitated electrode structures at a single triggering frequency. The results are well in line with data obtained using a calibrated reference instrument. The new setup holds for conductivity values spanning almost two orders of magnitude (river versus ocean water) without the need for equivalent circuit modelling. Temperature measurements were performed in four-point geometry with an on-chip platinum RTD (resistance temperature detector) in the temperature range between 2 °C and 40 °C, showing no hysteresis effects between warming and cooling cycles. Although the meander was not shielded against the liquid, the temperature calibration provided equivalent results to low conductive Milli-Q and highly conductive ocean water. The sensor is therefore suitable for inline and online monitoring purposes in recirculating aquaculture systems. KW - chip-based sensor setup KW - aquaculture KW - microfluidics KW - impedance spectroscopy KW - thermometry KW - electrical conductivity of liquids Y1 - 2024 U6 - https://doi.org/10.3390/mi15060755 SN - 2072-666X N1 - This article belongs to the Special Issue "Multisensor Arrays" N1 - Corresponding author: Michael J. Schöning VL - 15 IS - 6 PB - MDPI CY - Basel ER - TY - JOUR A1 - Zhantlessova, Sirina A1 - Savitskaya, Irina A1 - Kistaubayeva, Aida A1 - Ignatova, Ludmila A1 - Talipova, Aizhan A1 - Pogrebnjak, Alexander A1 - Digel, Ilya T1 - Correction: Zhantlessova et al. advanced “Green” prebiotic composite of bacterial cellulose/pullulan based on synthetic biology-powered microbial coculture strategy. Polymers 2022, 14, 3224 JF - Polymers Y1 - 2024 U6 - https://doi.org/10.3390/polym16131802 SN - 2073-4360 N1 - This article belongs to the Special Issue Cellulose Based Composites VL - 16 IS - 13 PB - MDPI CY - Basel ER - TY - JOUR A1 - Harris, Isaac A1 - Kleefeld, Andreas T1 - Analysis and computation of the transmission eigenvalues with a conductive boundary condition JF - Applicable Analysis N2 - We provide a new analytical and computational study of the transmission eigenvalues with a conductive boundary condition. These eigenvalues are derived from the scalar inverse scattering problem for an inhomogeneous material with a conductive boundary condition. The goal is to study how these eigenvalues depend on the material parameters in order to estimate the refractive index. The analytical questions we study are: deriving Faber–Krahn type lower bounds, the discreteness and limiting behavior of the transmission eigenvalues as the conductivity tends to infinity for a sign changing contrast. We also provide a numerical study of a new boundary integral equation for computing the eigenvalues. Lastly, using the limiting behavior we will numerically estimate the refractive index from the eigenvalues provided the conductivity is sufficiently large but unknown. KW - Boundary integral equations KW - Inverse spectral problem KW - Conductive boundary condition KW - Transmission eigenvalues Y1 - 2020 U6 - https://doi.org/10.1080/00036811.2020.1789598 SN - 1563-504X VL - 101 IS - 6 SP - 1880 EP - 1895 PB - Taylor & Francis CY - London ER - TY - JOUR A1 - Zhen, Manghao A1 - Liang, Yunpei A1 - Staat, Manfred A1 - Li, Quanqui A1 - Li, Jianbo T1 - Discontinuous fracture behaviors and constitutive model of sandstone specimens containing non-parallel prefabricated fissures under uniaxial compression JF - Theoretical and Applied Fracture Mechanics N2 - The deformation and damage laws of non-homogeneous irregular structural planes in rocks are the basis for studying the stability of rock engineering. To investigate the damage characteristics of rock containing non-parallel fissures, uniaxial compression tests and numerical simulations were conducted on sandstone specimens containing three non-parallel fissures inclined at 0°, 45° and 90° in this study. The characteristics of crack initiation and crack evolution of fissures with different inclinations were analyzed. A constitutive model for the discontinuous fractures of fissured sandstone was proposed. The results show that the fracture behaviors of fissured sandstone specimens are discontinuous. The stress–strain curves are non-smooth and can be divided into nonlinear crack closure stage, linear elastic stage, plastic stage and brittle failure stage, of which the plastic stage contains discontinuous stress drops. During the uniaxial compression test, the middle or ends of 0° fissures were the first to crack compared to 45° and 90° fissures. The end with small distance between 0° and 45° fissures cracked first, and the end with large distance cracked later. After the final failure, 0° fissures in all specimens were fractured, while 45° and 90° fissures were not necessarily fractured. Numerical simulation results show that the concentration of compressive stress at the tips of 0°, 45° and 90° fissures, as well as the concentration of tensile stress on both sides, decreased with the increase of the inclination angle. A constitutive model for the discontinuous fractures of fissured sandstone specimens was derived by combining the logistic model and damage mechanic theory. This model can well describe the discontinuous drops of stress and agrees well with the whole processes of the stress–strain curves of the fissured sandstone specimens. KW - Constitutive model KW - Damage mechanics theory KW - Discontinuous fractures KW - Uniaxial compression test KW - Non-parallel fissures Y1 - 2024 U6 - https://doi.org/10.1016/j.tafmec.2024.104373 SN - 0167-8442 VL - 131 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Dikta, Gerhard A1 - Reißel, Martin A1 - Harlaß, Carsten T1 - Semi-parametric survival function estimators deduced from an identifying Volterra type integral equation JF - Journal of multivariate analysis N2 - Based on an identifying Volterra type integral equation for randomly right censored observations from a lifetime distribution function F, we solve the corresponding estimating equation by an explicit and implicit Euler scheme. While the first approach results in some known estimators, the second one produces new semi-parametric and pre-smoothed Kaplan–Meier estimators which are real distribution functions rather than sub-distribution functions as the former ones are. This property of the new estimators is particular useful if one wants to estimate the expected lifetime restricted to the support of the observation time. Specifically, we focus on estimation under the semi-parametric random censorship model (SRCM), that is, a random censorship model where the conditional expectation of the censoring indicator given the observation belongs to a parametric family. We show that some estimated linear functionals which are based on the new semi-parametric estimator are strong consistent, asymptotically normal, and efficient under SRCM. In a small simulation study, the performance of the new estimator is illustrated under moderate sample sizes. Finally, we apply the new estimator to a well-known real dataset. KW - Volterra integral equation KW - Product-integration KW - Asymptotic efficiency KW - Semi-parametric random censorship model KW - Censored data KW - Survival analysis Y1 - 2016 U6 - https://doi.org/10.1016/j.jmva.2016.02.008 IS - 147 SP - 273 EP - 284 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Michael, Hackl A1 - Mayer, Katharina A1 - Weber, Mareike A1 - Staat, Manfred A1 - van Riet, Roger A1 - Burkhart, Klau Josef A1 - Müller, Lars Peter A1 - Wegmann, Kilian T1 - Plate osteosynthesis of proximal ulna fractures : a biomechanical micromotion analysis JF - The journal of hand surgery Y1 - 2017 U6 - https://doi.org/10.1016/j.jhsa.2017.05.014 SN - 0363-5023 VL - 42 IS - 10 SP - 834.e1 EP - 834.e7 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Clausnitzer, Julian A1 - Kleefeld, Andreas T1 - A spectral Galerkin exponential Euler time-stepping scheme for parabolic SPDEs on two-dimensional domains with a C² boundary JF - Discrete and Continuous Dynamical Systems - Series B N2 - We consider the numerical approximation of second-order semi-linear parabolic stochastic partial differential equations interpreted in the mild sense which we solve on general two-dimensional domains with a C² boundary with homogeneous Dirichlet boundary conditions. The equations are driven by Gaussian additive noise, and several Lipschitz-like conditions are imposed on the nonlinear function. We discretize in space with a spectral Galerkin method and in time using an explicit Euler-like scheme. For irregular shapes, the necessary Dirichlet eigenvalues and eigenfunctions are obtained from a boundary integral equation method. This yields a nonlinear eigenvalue problem, which is discretized using a boundary element collocation method and is solved with the Beyn contour integral algorithm. We present an error analysis as well as numerical results on an exemplary asymmetric shape, and point out limitations of the approach. KW - Nonlinear eigenvalue problems KW - Boundary integral equations, KW - Exponential Euler scheme, KW - Parabolic SPDEs Y1 - 2024 U6 - https://doi.org/10.3934/dcdsb.2023148 SN - 1531-3492 SN - 1553-524X (eISSN) VL - 29 IS - 4 SP - 1624 EP - 1651 PB - AIMS CY - Springfield ER - TY - JOUR A1 - Martín-Vaquero, J. A1 - Kleefeld, Andreas T1 - Solving nonlinear parabolic PDEs in several dimensions: Parallelized ESERK codes JF - Journal of Computational Physics N2 - There is a very large number of very important situations which can be modeled with nonlinear parabolic partial differential equations (PDEs) in several dimensions. In general, these PDEs can be solved by discretizing in the spatial variables and transforming them into huge systems of ordinary differential equations (ODEs), which are very stiff. Therefore, standard explicit methods require a large number of iterations to solve stiff problems. But implicit schemes are computationally very expensive when solving huge systems of nonlinear ODEs. Several families of Extrapolated Stabilized Explicit Runge-Kutta schemes (ESERK) with different order of accuracy (3 to 6) are derived and analyzed in this work. They are explicit methods, with stability regions extended, along the negative real semi-axis, quadratically with respect to the number of stages s, hence they can be considered to solve stiff problems much faster than traditional explicit schemes. Additionally, they allow the adaptation of the step length easily with a very small cost. Two new families of ESERK schemes (ESERK3 and ESERK6) are derived, and analyzed, in this work. Each family has more than 50 new schemes, with up to 84.000 stages in the case of ESERK6. For the first time, we also parallelized all these new variable step length and variable number of stages algorithms (ESERK3, ESERK4, ESERK5, and ESERK6). These parallelized strategies allow to decrease times significantly, as it is discussed and also shown numerically in two problems. Thus, the new codes provide very good results compared to other well-known ODE solvers. Finally, a new strategy is proposed to increase the efficiency of these schemes, and it is discussed the idea of combining ESERK families in one code, because typically, stiff problems have different zones and according to them and the requested tolerance the optimum order of convergence is different. KW - Multi-dimensional partial differential equations KW - Higher-order codes KW - Nonlinear PDEs Y1 - 2020 U6 - https://doi.org/10.1016/j.jcp.2020.109771 SN - 0021-9991 IS - 423 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Rhoden, Imke A1 - Ball, Christopher Stephen A1 - Grajewski, Matthias A1 - Kuckshinrich, Wilhelm T1 - Reverse engineering of stakeholder preferences – A multi-criteria assessment of the German passenger car sector JF - Renewable and Sustainable Energy Reviews N2 - Germany is a frontrunner in setting frameworks for the transition to a low-carbon system. The mobility sector plays a significant role in this shift, affecting different people and groups on multiple levels. Without acceptance from these stakeholders, emission targets are out of reach. This research analyzes how the heterogeneous preferences of various stakeholders align with the transformation of the mobility sector, looking at the extent to which the German transformation paths are supported and where stakeholders are located. Under the research objective of comparing stakeholders' preferences to identify which car segments require additional support for a successful climate transition, a status quo of stakeholders and car performance criteria is the foundation for the analysis. Stakeholders' hidden preferences hinder the derivation of criteria weightings from stakeholders; therefore, a ranking from observed preferences is used. This study's inverse multi-criteria decision analysis means that weightings can be predicted and used together with a recalibrated performance matrix to explore future preferences toward car segments. Results show that stakeholders prefer medium-sized cars, with the trend pointing towards the increased potential for alternative propulsion technologies and electrified vehicles. These insights can guide the improved targeting of policy supporting the energy and mobility transformation. Additionally, the method proposed in this work can fully handle subjective approaches while incorporating a priori information. A software implementation of the proposed method completes this work and is made publicly available. KW - Regionalization KW - Multi-criteria decision analysis KW - Preference assessment KW - E-Mobility KW - Mobility transition Y1 - 2023 U6 - https://doi.org/10.1016/j.rser.2023.113352 SN - 1364-0321 VL - 181 IS - July 2023 SP - Article number: 113352 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Kleefeld, Andreas A1 - Zimmermann, M. ED - Constanda, Christian ED - Bodmann, Bardo E.J. ED - Harris, Paul J. T1 - Computing Elastic Interior Transmission Eigenvalues JF - Integral Methods in Science and Engineering N2 - An alternative method is presented to numerically compute interior elastic transmission eigenvalues for various domains in two dimensions. This is achieved by discretizing the resulting system of boundary integral equations in combination with a nonlinear eigenvalue solver. Numerical results are given to show that this new approach can provide better results than the finite element method when dealing with general domains. Y1 - 2022 SN - 978-3-031-07171-3 U6 - https://doi.org/10.1007/978-3-031-07171-3_10 N1 - Corresponding author: Andreas Kleefeld SP - 139 EP - 155 PB - Birkhäuser CY - Cham ER - TY - JOUR A1 - Röthenbacher, Annika A1 - Cesari, Matteo A1 - Doppler, Christopher E.J. A1 - Okkels, Niels A1 - Willemsen, Nele A1 - Sembowski, Nora A1 - Seger, Aline A1 - Lindner, Marie A1 - Brune, Corinna A1 - Stefani, Ambra A1 - Högl, Birgit A1 - Bialonski, Stephan A1 - Borghammer, Per A1 - Fink, Gereon R. A1 - Schober, Martin A1 - Sommerauer, Michael T1 - RBDtector: an open-source software to detect REM sleep without atonia according to visual scoring criteria JF - Scientific Reports N2 - REM sleep without atonia (RSWA) is a key feature for the diagnosis of rapid eye movement (REM) sleep behaviour disorder (RBD). We introduce RBDtector, a novel open-source software to score RSWA according to established SINBAR visual scoring criteria. We assessed muscle activity of the mentalis, flexor digitorum superficialis (FDS), and anterior tibialis (AT) muscles. RSWA was scored manually as tonic, phasic, and any activity by human scorers as well as using RBDtector in 20 subjects. Subsequently, 174 subjects (72 without RBD and 102 with RBD) were analysed with RBDtector to show the algorithm’s applicability. We additionally compared RBDtector estimates to a previously published dataset. RBDtector showed robust conformity with human scorings. The highest congruency was achieved for phasic and any activity of the FDS. Combining mentalis any and FDS any, RBDtector identified RBD subjects with 100% specificity and 96% sensitivity applying a cut-off of 20.6%. Comparable performance was obtained without manual artefact removal. RBD subjects also showed muscle bouts of higher amplitude and longer duration. RBDtector provides estimates of tonic, phasic, and any activity comparable to human scorings. RBDtector, which is freely available, can help identify RBD subjects and provides reliable RSWA metrics. Y1 - 2022 U6 - https://doi.org/10.1038/s41598-022-25163-9 SN - 2045-2322 VL - 12 IS - Article number: 20886 SP - 1 EP - 14 PB - Springer Nature CY - London ER - TY - JOUR A1 - Gaigall, Daniel T1 - Rothman–Woodroofe symmetry test statistic revisited JF - Computational Statistics & Data Analysis N2 - The Rothman–Woodroofe symmetry test statistic is revisited on the basis of independent but not necessarily identically distributed random variables. The distribution-freeness if the underlying distributions are all symmetric and continuous is obtained. The results are applied for testing symmetry in a meta-analysis random effects model. The consistency of the procedure is discussed in this situation as well. A comparison with an alternative proposal from the literature is conducted via simulations. Real data are analyzed to demonstrate how the new approach works in practice. Y1 - 2020 U6 - https://doi.org/10.1016/j.csda.2019.106837 SN - 0167-9473 VL - 2020 IS - 142 SP - Artikel 106837 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Uysal, Karya A1 - Firat, Ipek Serat A1 - Creutz, Till A1 - Aydin, Inci Cansu A1 - Artmann, Gerhard A1 - Teusch, Nicole A1 - Temiz Artmann, Aysegül T1 - A novel in vitro wound healing assay using free-standing, ultra-thin PDMS membranes JF - membranes N2 - Advances in polymer science have significantly increased polymer applications in life sciences. We report the use of free-standing, ultra-thin polydimethylsiloxane (PDMS) membranes, called CellDrum, as cell culture substrates for an in vitro wound model. Dermal fibroblast monolayers from 28- and 88-year-old donors were cultured on CellDrums. By using stainless steel balls, circular cell-free areas were created in the cell layer (wounding). Sinusoidal strain of 1 Hz, 5% strain, was applied to membranes for 30 min in 4 sessions. The gap circumference and closure rate of un-stretched samples (controls) and stretched samples were monitored over 4 days to investigate the effects of donor age and mechanical strain on wound closure. A significant decrease in gap circumference and an increase in gap closure rate were observed in trained samples from younger donors and control samples from older donors. In contrast, a significant decrease in gap closure rate and an increase in wound circumference were observed in the trained samples from older donors. Through these results, we propose the model of a cell monolayer on stretchable CellDrums as a practical tool for wound healing research. The combination of biomechanical cell loading in conjunction with analyses such as gene/protein expression seems promising beyond the scope published here. Y1 - 2022 U6 - https://doi.org/10.3390/membranes13010022 N1 - This article belongs to the Special Issue "Latest Scientific Discoveries in Polymer Membranes" VL - 2023 IS - 13(1) PB - MDPI CY - Basel ER - TY - JOUR A1 - Ayala, Rafael Ceja A1 - Harris, Isaac A1 - Kleefeld, Andreas T1 - Direct sampling method via Landweber iteration for an absorbing scatterer with a conductive boundary JF - Inverse Problems and Imaging N2 - In this paper, we consider the inverse shape problem of recovering isotropic scatterers with a conductive boundary condition. Here, we assume that the measured far-field data is known at a fixed wave number. Motivated by recent work, we study a new direct sampling indicator based on the Landweber iteration and the factorization method. Therefore, we prove the connection between these reconstruction methods. The method studied here falls under the category of qualitative reconstruction methods where an imaging function is used to recover the absorbing scatterer. We prove stability of our new imaging function as well as derive a discrepancy principle for recovering the regularization parameter. The theoretical results are verified with numerical examples to show how the reconstruction performs by the new Landweber direct sampling method. Y1 - 2024 U6 - https://doi.org/10.3934/ipi.2023051 SN - 1930-8337 SN - 1930-8345 (eISSN) VL - 18 IS - 3 SP - 708 EP - 729 PB - AIMS CY - Springfield ER - TY - JOUR A1 - Frotscher, Ralf A1 - Muanghong, Danita A1 - Dursun, Gözde A1 - Goßmann, Matthias A1 - Temiz Artmann, Aysegül A1 - Staat, Manfred T1 - Sample-specific adaption of an improved electro-mechanical model of in vitro cardiac tissue JF - Journal of Biomechanics N2 - We present an electromechanically coupled computational model for the investigation of a thin cardiac tissue construct consisting of human-induced pluripotent stem cell-derived atrial, ventricular and sinoatrial cardiomyocytes. The mechanical and electrophysiological parts of the finite element model, as well as their coupling are explained in detail. The model is implemented in the open source finite element code Code_Aster and is employed for the simulation of a thin circular membrane deflected by a monolayer of autonomously beating, circular, thin cardiac tissue. Two cardio-active drugs, S-Bay K8644 and veratridine, are applied in experiments and simulations and are investigated with respect to their chronotropic effects on the tissue. These results demonstrate the potential of coupled micro- and macroscopic electromechanical models of cardiac tissue to be adapted to experimental results at the cellular level. Further model improvements are discussed taking into account experimentally measurable quantities that can easily be extracted from the obtained experimental results. The goal is to estimate the potential to adapt the presented model to sample specific cell cultures. KW - hiPS cardiomyocytes KW - Homogenization KW - Hodgkin–Huxley models KW - Frequency adaption KW - Electromechanical modeling KW - Drug simulation KW - Computational biomechanics KW - Cardiac tissue Y1 - 2016 U6 - https://doi.org/10.1016/j.jbiomech.2016.01.039 SN - 0021-9290 (Print) SN - 1873-2380 (Online) VL - 49 IS - 12 SP - 2428 EP - 2435 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Leschinger, Tim A1 - Birgel, Stefan A1 - Hackl, Michael A1 - Staat, Manfred A1 - Müller, Lars Peter A1 - Wegmann, Kilian T1 - A musculoskeletal shoulder simulation of moment arms and joint reaction forces after medialization of the supraspinatus footprint in rotator cuff repair JF - Computer Methods in Biomechanics and Biomedical Engineering Y1 - 2019 U6 - https://doi.org/10.1080/10255842.2019.1572749 IS - Early view PB - Taylor & Francis CY - London ER - TY - JOUR A1 - Harris, Isaac A1 - Kleefeld, Andreas T1 - The inverse scattering problem for a conductive boundary condition and transmission eigenvalues JF - Applicable Analysis N2 - In this paper, we consider the inverse scattering problem associated with an inhomogeneous media with a conductive boundary. In particular, we are interested in two problems that arise from this inverse problem: the inverse conductivity problem and the corresponding interior transmission eigenvalue problem. The inverse conductivity problem is to recover the conductive boundary parameter from the measured scattering data. We prove that the measured scatted data uniquely determine the conductivity parameter as well as describe a direct algorithm to recover the conductivity. The interior transmission eigenvalue problem is an eigenvalue problem associated with the inverse scattering of such materials. We investigate the convergence of the eigenvalues as the conductivity parameter tends to zero as well as prove existence and discreteness for the case of an absorbing media. Lastly, several numerical and analytical results support the theory and we show that the inside–outside duality method can be used to reconstruct the interior conductive eigenvalues. KW - Transmission eigenvalues KW - Conductive boundary condition KW - Inverse scattering Y1 - 2018 U6 - https://doi.org/10.1080/00036811.2018.1504028 SN - 1563-504X VL - 99 IS - 3 SP - 508 EP - 529 PB - Taylor & Francis CY - London ER - TY - JOUR A1 - Gaigall, Daniel T1 - Test for Changes in the Modeled Solvency Capital Requirement of an Internal Risk Model JF - ASTIN Bulletin N2 - In the context of the Solvency II directive, the operation of an internal risk model is a possible way for risk assessment and for the determination of the solvency capital requirement of an insurance company in the European Union. A Monte Carlo procedure is customary to generate a model output. To be compliant with the directive, validation of the internal risk model is conducted on the basis of the model output. For this purpose, we suggest a new test for checking whether there is a significant change in the modeled solvency capital requirement. Asymptotic properties of the test statistic are investigated and a bootstrap approximation is justified. A simulation study investigates the performance of the test in the finite sample case and confirms the theoretical results. The internal risk model and the application of the test is illustrated in a simplified example. The method has more general usage for inference of a broad class of law-invariant and coherent risk measures on the basis of a paired sample. KW - Bootstrap KW - Empirical process KW - Functional Delta Method KW - Hadamard differentiability KW - Paired sample Y1 - 2021 U6 - https://doi.org/10.1017/asb.2021.20 SN - 1783-1350 VL - 51 IS - 3 SP - 813 EP - 837 PB - Cambridge Univ. Press CY - Cambridge ER - TY - JOUR A1 - Baringhaus, Ludwig A1 - Gaigall, Daniel A1 - Thiele, Jan Philipp T1 - Statistical inference for L²-distances to uniformity JF - Computational Statistics N2 - The paper deals with the asymptotic behaviour of estimators, statistical tests and confidence intervals for L²-distances to uniformity based on the empirical distribution function, the integrated empirical distribution function and the integrated empirical survival function. Approximations of power functions, confidence intervals for the L²-distances and statistical neighbourhood-of-uniformity validation tests are obtained as main applications. The finite sample behaviour of the procedures is illustrated by a simulation study. KW - Integrated empirical distribution (survival) function KW - Goodness-of-fit tests for uniformity KW - Numerical inversion of Laplace transforms KW - Coverage probability KW - Equivalence test Y1 - 2018 U6 - https://doi.org/10.1007/s00180-018-0820-0 SN - 1613-9658 VL - 2018 IS - 33 SP - 1863 EP - 1896 PB - Springer CY - Berlin ER - TY - JOUR A1 - Schöning, Michael Josef A1 - Bronder, Thomas A1 - Wu, Chunsheng A1 - Scheja, Sabrina A1 - Jessing, Max A1 - Metzger-Boddien, Christoph A1 - Keusgen, Michael A1 - Poghossian, Arshak T1 - Label-Free DNA Detection with Capacitive Field-Effect Devices—Challenges and Opportunities JF - Proceedings N2 - Field-effect EIS (electrolyte-insulator-semiconductor) sensors modified with a positively charged weak polyelectrolyte layer have been applied for the electrical detection of DNA (deoxyribonucleic acid) immobilization and hybridization by the intrinsic molecular charge. The EIS sensors are able to detect the existence of target DNA amplicons in PCR (polymerase chain reaction) samples and thus, can be used as tool for a quick verification of DNA amplification and the successful PCR process. Due to their miniaturized setup, compatibility with advanced micro- and nanotechnologies, and ability to detect biomolecules by their intrinsic molecular charge, those sensors can serve as possible platform for the development of label-free DNA chips. Possible application fields as well as challenges and limitations will be discussed. Y1 - 2017 U6 - https://doi.org/10.3390/proceedings1080719 SN - 2504-3900 N1 - This article belongs to the Proceedings of "Proceedings of the 5th International Symposium on Sensor Science (I3S 2017)" VL - 1 IS - 8 SP - Artikel 719 PB - MDPI CY - Basel ER - TY - JOUR A1 - Gaigall, Daniel T1 - Testing marginal homogeneity of a continuous bivariate distribution with possibly incomplete paired data JF - Metrika N2 - We discuss the testing problem of homogeneity of the marginal distributions of a continuous bivariate distribution based on a paired sample with possibly missing components (missing completely at random). Applying the well-known two-sample Crámer–von-Mises distance to the remaining data, we determine the limiting null distribution of our test statistic in this situation. It is seen that a new resampling approach is appropriate for the approximation of the unknown null distribution. We prove that the resulting test asymptotically reaches the significance level and is consistent. Properties of the test under local alternatives are pointed out as well. Simulations investigate the quality of the approximation and the power of the new approach in the finite sample case. As an illustration we apply the test to real data sets. KW - Marginal homogeneity test KW - Crámer–von-Mises distance KW - Paired sample KW - Incomplete data KW - Resampling test Y1 - 2019 U6 - https://doi.org/10.1007/s00184-019-00742-5 SN - 1435-926X VL - 2020 IS - 83 SP - 437 EP - 465 PB - Springer ER - TY - JOUR A1 - Richter, Charlotte A1 - Braunstein, Bjoern A1 - Winnard, Andrew A1 - Nasser, Mona A1 - Weber, T. T1 - Human Biomechanical and Cardiopulmonary Responses to Partial Gravity – A Systematic Review JF - Frontiers in physiology Y1 - 2017 U6 - https://doi.org/10.3389/fphys.2017.00583 IS - 8, article 583 ER - TY - JOUR A1 - Gaigall, Daniel T1 - On a new approach to the multi-sample goodness-of-fit problem JF - Communications in Statistics - Simulation and Computation N2 - Suppose we have k samples X₁,₁,…,X₁,ₙ₁,…,Xₖ,₁,…,Xₖ,ₙₖ with different sample sizes ₙ₁,…,ₙₖ and unknown underlying distribution functions F₁,…,Fₖ as observations plus k families of distribution functions {G₁(⋅,ϑ);ϑ∈Θ},…,{Gₖ(⋅,ϑ);ϑ∈Θ}, each indexed by elements ϑ from the same parameter set Θ, we consider the new goodness-of-fit problem whether or not (F₁,…,Fₖ) belongs to the parametric family {(G₁(⋅,ϑ),…,Gₖ(⋅,ϑ));ϑ∈Θ}. New test statistics are presented and a parametric bootstrap procedure for the approximation of the unknown null distributions is discussed. Under regularity assumptions, it is proved that the approximation works asymptotically, and the limiting distributions of the test statistics in the null hypothesis case are determined. Simulation studies investigate the quality of the new approach for small and moderate sample sizes. Applications to real-data sets illustrate how the idea can be used for verifying model assumptions. KW - Goodness-of-fit test KW - Multi-sample problem KW - Parametric bootstrap Y1 - 2019 U6 - https://doi.org/10.1080/03610918.2019.1618472 SN - 1532-4141 VL - 53 IS - 10 SP - 2971 EP - 2989 PB - Taylor & Francis CY - London ER - TY - JOUR A1 - Laack, Walter van T1 - Our world is well ordered in measurement and number : or why natural constants are as they are JF - American Journal of Humanities and Social Sciences (AHSS) N2 - All the important natural constants can be logically explained with and derived from the first four ordinal numbers, 1, 2, 3 and 4, its addition to ten and finally the standard values for obviously maximal feasibility Ω and the optimum in our world, the Golden Section (GS), i.e. the number sequences 273 and 618. They both are the first three numbers of irrational results by an arithmetical transformation of simple geometrical relationships by creating multiplicity out of singularity. Both of them show that the infinite is inherent in finiteness and explain in a simple way the smallest deviations and fluctuations between the physical AS-IS state and the obvious spiritual ideal behind: Wherever we look in this world, and especially in important key-positions, we regularly find these sequences. All of the above mentioned numbers so seem to be key players in our world, what can be demonstrated by the derivation of natural constants. Y1 - 2013 U6 - https://doi.org/10.11634/232907811301390 SN - 2329-079X SN - 2329-0781 VL - 1 IS - 4 SP - 219 EP - 221 ER - TY - JOUR A1 - Bronder, Thomas A1 - Jessing, Max P. A1 - Poghossian, Arshak A1 - Keusgen, Michael A1 - Schöning, Michael Josef T1 - Detection of PCR-Amplified Tuberculosis DNA Fragments with Polyelectrolyte-Modified Field-Effect Sensors JF - Analytical Chemistry N2 - Field-effect-based electrolyte-insulator-semiconductor (EIS) sensors were modified with a bilayer of positively charged weak polyelectrolyte (poly(allylamine hydrochloride) (PAH)) and probe single-stranded DNA (ssDNA) and are used for the detection of complementary single-stranded target DNA (cDNA) in different test solutions. The sensing mechanism is based on the detection of the intrinsic molecular charge of target cDNA molecules after the hybridization event between cDNA and immobilized probe ssDNA. The test solutions contain synthetic cDNA oligonucleotides (with a sequence of tuberculosis mycobacteria genome) or PCR-amplified DNA (which origins from a template DNA strand that has been extracted from Mycobacterium avium paratuberculosis-spiked human sputum samples), respectively. Sensor responses up to 41 mV have been measured for the test solutions with DNA, while only small signals of ∼5 mV were detected for solutions without DNA. The lower detection limit of the EIS sensors was ∼0.3 nM, and the sensitivity was ∼7.2 mV/decade. Fluorescence experiments using SybrGreen I fluorescence dye support the electrochemical results. Y1 - 2018 U6 - https://doi.org/10.1021/acs.analchem.8b01807 SN - 0003-2700 VL - 90 IS - 12 SP - 7747 EP - 7753 PB - ACS Publications CY - Washington, DC ER - TY - JOUR A1 - Ditzhaus, Marc A1 - Gaigall, Daniel T1 - A consistent goodness-of-fit test for huge dimensional and functional data JF - Journal of Nonparametric Statistics N2 - A nonparametric goodness-of-fit test for random variables with values in a separable Hilbert space is investigated. To verify the null hypothesis that the data come from a specific distribution, an integral type test based on a Cramér-von-Mises statistic is suggested. The convergence in distribution of the test statistic under the null hypothesis is proved and the test's consistency is concluded. Moreover, properties under local alternatives are discussed. Applications are given for data of huge but finite dimension and for functional data in infinite dimensional spaces. A general approach enables the treatment of incomplete data. In simulation studies the test competes with alternative proposals. KW - Cramér-von-Mises statistic KW - separable Hilbert space KW - huge dimensional data KW - functional data Y1 - 2018 U6 - https://doi.org/10.1080/10485252.2018.1486402 SN - 1029-0311 VL - 30 IS - 4 SP - 834 EP - 859 PB - Taylor & Francis CY - Abingdon ER - TY - JOUR A1 - Gaigall, Daniel A1 - Gerstenberg, Julian A1 - Trinh, Thi Thu Ha T1 - Empirical process of concomitants for partly categorial data and applications in statistics JF - Bernoulli N2 - On the basis of independent and identically distributed bivariate random vectors, where the components are categorial and continuous variables, respectively, the related concomitants, also called induced order statistic, are considered. The main theoretical result is a functional central limit theorem for the empirical process of the concomitants in a triangular array setting. A natural application is hypothesis testing. An independence test and a two-sample test are investigated in detail. The fairly general setting enables limit results under local alternatives and bootstrap samples. For the comparison with existing tests from the literature simulation studies are conducted. The empirical results obtained confirm the theoretical findings. KW - bootstrap KW - Categorial variable KW - Concomitant KW - Empirical process KW - Independence test Y1 - 2022 U6 - https://doi.org/10.3150/21-BEJ1367 SN - 1573-9759 VL - 28 IS - 2 SP - 803 EP - 829 PB - International Statistical Institute CY - Den Haag, NL ER - TY - JOUR A1 - Artmann, Gerhard A1 - Grebe, R. A1 - Homrighausen, A. A1 - Wolff, H. A1 - Teitel, P. A1 - Schmid-Schönbein, H. T1 - Response of normal and diabetic erythrocytes to membrane deformation by chemical and mechanical forces. Artmann, Gerhard Michael; Grebe, R.; Homrighausen, A.; Wolff, H.; Teitel, P.; Schmid-Schönbein, H. JF - 12. Jahrestagung der Gesellschaft für Mikrozirkulation Y1 - 1988 SP - 196 EP - 200 PB - Karger [u.a.] CY - Basel [u.a.] ER - TY - JOUR A1 - Jung, Alexander A1 - Müller, Wolfram A1 - Staat, Manfred T1 - Optimization of the flight technique in ski jumping: the influence of wind Y1 - 2019 U6 - https://doi.org/10.1016/j.jbiomech.2019.03.023 IS - Early view PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Jildeh, Zaid B. A1 - Oberländer, Jan A1 - Kirchner, Patrick A1 - Keusgen, Michael A1 - Wagner, Patrick H. A1 - Schöning, Michael Josef T1 - Experimental and Numerical Analyzes of a Sensor Based on Interdigitated Electrodes for Studying Microbiological Alterations JF - physica status solidi (a): applications and materials science N2 - In this work, a cell-based biosensor to evaluate the sterilization efficacy of hydrogen peroxide vapor sterilization processes is characterized. The transducer of the biosensor is based on interdigitated gold electrodes fabricated on an inert glass substrate. Impedance spectroscopy is applied to evaluate the sensor behavior and the alteration of test microorganisms due to the sterilization process. These alterations are related to changes in relative permittivity and electrical conductivity of the bacterial spores. Sensor measurements are conducted with and without bacterial spores (Bacillus atrophaeus), as well as after an industrial sterilization protocol. Equivalent two-dimensional numerical models based on finite element method of the periodic finger structures of the interdigitated gold electrodes are designed and validated using COMSOL® Multiphysics software by the application of known dielectric properties. The validated models are used to compute the electrical properties at different sensor states (blank, loaded with spores, and after sterilization). As a final result, we will derive and tabulate the frequency-dependent electrical parameters of the spore layer using a novel model that combines experimental data with numerical optimization techniques. Y1 - 2018 U6 - https://doi.org/10.1002/pssa.201700920 SN - 1862-6319 VL - 215 IS - 15 PB - Wiley-VCH CY - Weinheim ER - TY - JOUR A1 - Ditzhaus, Marc A1 - Gaigall, Daniel T1 - Testing marginal homogeneity in Hilbert spaces with applications to stock market returns JF - Test N2 - This paper considers a paired data framework and discusses the question of marginal homogeneity of bivariate high-dimensional or functional data. The related testing problem can be endowed into a more general setting for paired random variables taking values in a general Hilbert space. To address this problem, a Cramér–von-Mises type test statistic is applied and a bootstrap procedure is suggested to obtain critical values and finally a consistent test. The desired properties of a bootstrap test can be derived that are asymptotic exactness under the null hypothesis and consistency under alternatives. Simulations show the quality of the test in the finite sample case. A possible application is the comparison of two possibly dependent stock market returns based on functional data. The approach is demonstrated based on historical data for different stock market indices. Y1 - 2022 U6 - https://doi.org/10.1007/s11749-022-00802-5 SN - 1863-8260 VL - 2022 IS - 31 SP - 749 EP - 770 PB - Springer ER - TY - JOUR A1 - Kleefeld, Andreas A1 - Pieronek, J. T1 - Elastic transmission eigenvalues and their computation via the method of fundamental solutions JF - Applicable Analysis N2 - A stabilized version of the fundamental solution method to catch ill-conditioning effects is investigated with focus on the computation of complex-valued elastic interior transmission eigenvalues in two dimensions for homogeneous and isotropic media. Its algorithm can be implemented very shortly and adopts to many similar partial differential equation-based eigenproblems as long as the underlying fundamental solution function can be easily generated. We develop a corroborative approximation analysis which also implicates new basic results for transmission eigenfunctions and present some numerical examples which together prove successful feasibility of our eigenvalue recovery approach. KW - elastic scattering KW - method of fundamental solutions KW - Interior transmission eigenvalues Y1 - 2020 U6 - https://doi.org/10.1080/00036811.2020.1721473 SN - 1563-504X VL - 100 IS - 16 SP - 3445 EP - 3462 PB - Taylore & Francis CY - London ER - TY - JOUR A1 - Horbach, Andreas A1 - Duong, Minh Tuan A1 - Staat, Manfred T1 - Modelling of compressible and orthotropic surgical mesh implants based on optical deformation measurement JF - Journal of the mechanical behavior of biomedical materials Y1 - 2017 U6 - https://doi.org/10.1016/j.jmbbm.2017.06.012 SN - 1751-6161 VL - 74 SP - 400 EP - 410 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Richter, Charlotte A1 - Braunstein, Bjoern A1 - Stäudle, Benjamin A1 - Attias, Julia A1 - Suess, Alexander A1 - Weber, Tobias A1 - Mileva, Katja N. A1 - Rittweger, Joern A1 - Green, David A. A1 - Albracht, Kirsten T1 - Gastrocnemius medialis contractile behavior is preserved during 30% body weight supported gait training JF - Frontiers in Sports and Active Living N2 - Rehabilitative body weight supported gait training aims at restoring walking function as a key element in activities of daily living. Studies demonstrated reductions in muscle and joint forces, while kinematic gait patterns appear to be preserved with up to 30% weight support. However, the influence of body weight support on muscle architecture, with respect to fascicle and series elastic element behavior is unknown, despite this having potential clinical implications for gait retraining. Eight males (31.9 ± 4.7 years) walked at 75% of the speed at which they typically transition to running, with 0% and 30% body weight support on a lower-body positive pressure treadmill. Gastrocnemius medialis fascicle lengths and pennation angles were measured via ultrasonography. Additionally, joint kinematics were analyzed to determine gastrocnemius medialis muscle–tendon unit lengths, consisting of the muscle's contractile and series elastic elements. Series elastic element length was assessed using a muscle–tendon unit model. Depending on whether data were normally distributed, a paired t-test or Wilcoxon signed rank test was performed to determine if body weight supported walking had any effects on joint kinematics and fascicle–series elastic element behavior. Walking with 30% body weight support had no statistically significant effect on joint kinematics and peak series elastic element length. Furthermore, at the time when peak series elastic element length was achieved, and on average across the entire stance phase, muscle–tendon unit length, fascicle length, pennation angle, and fascicle velocity were unchanged with respect to body weight support. In accordance with unchanged gait kinematics, preservation of fascicle–series elastic element behavior was observed during walking with 30% body weight support, which suggests transferability of gait patterns to subsequent unsupported walking. KW - AlterG KW - rehabilitation KW - gait KW - walking KW - ultrasound imaging KW - series elastic element behavior KW - muscle fascicle behavior KW - unloading Y1 - 2021 U6 - https://doi.org/10.3389/fspor.2020.614559 SN - 2624-9367 VL - 2021 IS - 2 PB - Frontiers CY - Lausanne ER - TY - JOUR A1 - Duong, Minh Tuan A1 - Nguyen, Nhu Huynh A1 - Staat, Manfred T1 - Physical response of hyperelastic models for composite materials and soft tissues JF - Asia pacific journal on computational engineering Y1 - 2015 U6 - https://doi.org/10.1186/s40540-015-0015-x SN - 2196-1166 VL - 2 IS - 3 (December 2015) SP - 1 EP - 18 ER - TY - JOUR A1 - Molinnus, Denise A1 - Poghossian, Arshak A1 - Keusgen, Michael A1 - Katz, Evgeny A1 - Schöning, Michael Josef T1 - Coupling of Biomolecular Logic Gates with Electronic Transducers: From Single Enzyme Logic Gates to Sense/Act/Treat Chips JF - Electroanalysis N2 - The integration of biomolecular logic principles with electronic transducers allows designing novel digital biosensors with direct electrical output, logically triggered drug-release, and closed-loop sense/act/treat systems. This opens new opportunities for advanced personalized medicine in the context of theranostics. In the present work, we will discuss selected examples of recent developments in the field of interfacing enzyme logic gates with electrodes and semiconductor field-effect devices. Special attention is given to an enzyme OR/Reset logic gate based on a capacitive field-effect electrolyte-insulator-semiconductor sensor modified with a multi-enzyme membrane. Further examples are a digital adrenaline biosensor based on an AND logic gate with binary YES/NO output and an integrated closed-loop sense/act/treat system comprising an amperometric glucose sensor, a hydrogel actuator, and an insulin (drug) sensor. Y1 - 2017 U6 - https://doi.org/10.1002/elan.201700208 SN - 1521-4109 VL - 29 IS - 8 SP - 1840 EP - 1849 PB - Wiley CY - Weinheim ER - TY - JOUR A1 - Poghossian, Arshak A1 - Yoshinobu, Tatsuo A1 - Simonis, A. A1 - Ecken, H. A1 - Lüth, Hans A1 - Schöning, Michael Josef T1 - Penicillin detection by means of field-effect based sensors: EnFET, capacitive EIS sensor or LAPS? JF - Sensors and Actuators B. 78 (2001), H. 1-3 Y1 - 2001 SN - 0925-4005 SP - 237 EP - 242 ER - TY - JOUR A1 - Poghossian, Arshak A1 - Schöning, Michael Josef T1 - Chemical and biological field-effect sensors for liquids – a status report JF - Handbook of biosensors and biochips / ed. Robert S. Marks ... Bd. 1 Y1 - 2007 SN - 978-0-470-01905-4 SP - 395 EP - 412 PB - Wiley CY - Chichester ER - TY - JOUR A1 - Staat, Manfred A1 - Heitzer, M. T1 - FEM-computation of load carrying capacity of highly loaded passive components by direct methods. Heitzer, M. ; Staat, M. JF - Nuclear Engineering and Design. 193 (1999), H. 3 Y1 - 1999 SN - 0029-5493 SP - 349 EP - 358 ER - TY - JOUR A1 - Poghossian, Arshak A1 - Weil, M. A1 - Cherstvy, A. G. A1 - Schöning, Michael Josef T1 - Electrical monitoring of polyelectrolyte multilayer formation by means of capacitive field-effect devices JF - Analytical and bioanalytical chemistry N2 - The semiconductor field-effect platform represents a powerful tool for detecting the adsorption and binding of charged macromolecules with direct electrical readout. In this work, a capacitive electrolyte–insulator–semiconductor (EIS) field-effect sensor consisting of an Al-p-Si-SiO2 structure has been applied for real-time in situ electrical monitoring of the layer-by-layer formation of polyelectrolyte (PE) multilayers (PEM). The PEMs were deposited directly onto the SiO2 surface without any precursor layer or drying procedures. Anionic poly(sodium 4-styrene sulfonate) and cationic weak polyelectrolyte poly(allylamine hydrochloride) have been chosen as a model system. The effect of the ionic strength of the solution, polyelectrolyte concentration, number and polarity of the PE layers on the characteristics of the PEM-modified EIS sensors have been studied by means of capacitance–voltage and constant-capacitance methods. In addition, the thickness, surface morphology, roughness and wettabilityof the PE mono- and multilayers have been characterised by ellipsometry, atomic force microscopy and water contact-angle methods, respectively. To explain potential oscillations on the gate surface and signal behaviour of the capacitive field-effect EIS sensor modified with a PEM, a simplified electrostatic model that takes into account the reduced electrostatic screening of PE charges by mobile ions within the PEM has been proposed and discussed. Y1 - 2013 U6 - https://doi.org/10.1007/s00216-013-6951-9 SN - 1432-1130 ; 1618-2642 VL - 405 IS - 20 SP - 6425 EP - 6436 PB - Springer CY - Berlin ER - TY - JOUR A1 - Schöning, Michael Josef A1 - Poghossian, Arshak T1 - Recent advances in biologically sensitive field-effect transistors (BioFETs) JF - Analyst. 127 (2002) Y1 - 2002 SN - 0003-2654 SP - 1137 EP - 1151 ER -