TY - JOUR A1 - Monakhova, Yulia A1 - Diehl, Bernd W.K. T1 - Novel approach of qNMR workflow by standardization using 2H integral: Application to any intrinsic calibration standard JF - Talanta N2 - Quantitative nuclear magnetic resonance (qNMR) is routinely performed by the internal or external standardization. The manuscript describes a simple alternative to these common workflows by using NMR signal of another active nuclei of calibration compound. For example, for any arbitrary compound quantification by NMR can be based on the use of an indirect concentration referencing that relies on a solvent having both 1H and 2H signals. To perform high-quality quantification, the deuteration level of the utilized deuterated solvent has to be estimated. In this contribution the new method was applied to the determination of deuteration levels in different deuterated solvents (MeOD, ACN, CDCl3, acetone, benzene, DMSO-d6). Isopropanol-d6, which contains a defined number of deuterons and protons, was used for standardization. Validation characteristics (precision, accuracy, robustness) were calculated and the results showed that the method can be used in routine practice. Uncertainty budget was also evaluated. In general, this novel approach, using standardization by 2H integral, benefits from reduced sample preparation steps and uncertainties, and can be applied in different application areas (purity determination, forensics, pharmaceutical analysis, etc.). KW - qNMR KW - Deuterium NMR KW - Deuterated solvents KW - Standardization Y1 - 2021 SN - 0039-9140 U6 - https://doi.org/10.1016/j.talanta.2020.121504 VL - 222 IS - Article number: 121504 PB - Elsevier ER - TY - JOUR A1 - Monakhova, Yulia A1 - Diehl, Bernd W.K. T1 - Multinuclear NMR screening of pharmaceuticals using standardization by 2H integral of a deuterated solvent JF - Journal of Pharmaceutical and Biomedical Analysis N2 - NMR standardization approach that uses the 2H integral of deuterated solvent for quantitative multinuclear analysis of pharmaceuticals is described. As a proof of principle, the existing NMR procedure for the analysis of heparin products according to US Pharmacopeia monograph is extended to the determination of Na+ and Cl- content in this matrix. Quantification is performed based on the ratio of a 23Na (35Cl) NMR integral and 2H NMR signal of deuterated solvent, D2O, acquired using the specific spectrometer hardware. As an alternative, the possibility of 133Cs standardization using the addition of Cs2CO3 stock solution is shown. Validation characteristics (linearity, repeatability, sensitivity) are evaluated. A holistic NMR profiling of heparin products can now also be used for the quantitative determination of inorganic compounds in a single analytical run using a single sample. In general, the new standardization methodology provides an appealing alternative for the NMR screening of inorganic and organic components in pharmaceutical products. KW - NMR spectroscopy KW - Inorganic ions KW - Heparin KW - Standardization Y1 - 2022 SN - 0731-7085 U6 - https://doi.org/10.1016/j.jpba.2021.114530 VL - 209 IS - Article number: 114530 PB - Elsevier 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 - Heuermann, Holger A1 - Sadeghfam, Arash T1 - Enhanced system architecture for rugged wide band data transmission / Sadeghfam, A. ; Heuermann, H. JF - European Radar Conference, 2009 : EuRAD 2009 ; Sept. 30 - Oct. 2 2009, Rome, Italy ; part of the European Microwave Week (EuMW) / sponsored by EuMA, European Microwave Association Y1 - 2009 SN - 978-2-87487-014-9 N1 - Proceedings of the 6th European Radar Conference SP - 347 EP - 350 PB - IEEE CY - Piscataway, NJ ER - TY - JOUR A1 - Trapp, Svenja A1 - Lammers, Tom A1 - Engudar, Gokce A1 - Hoehr, Cornelia A1 - Denkova, Antonia G. A1 - Paulßen, Elisabeth A1 - de Kruijff, Robin M. T1 - Membrane-based microfluidic solvent extraction of Ga-68 from aqueous Zn solutions: towards an automated cyclotron production loop JF - EJNMMI Radiopharmacy and Chemistry KW - Microfluidic solvent extraction KW - Ga-68 KW - Cyclotron production KW - Medical radionuclide production KW - Metal contaminants Y1 - 2023 U6 - https://doi.org/10.1186/s41181-023-00195-2 SN - 2365-421X VL - 2023 IS - 8, Article number: 9 SP - 1 EP - 14 PB - Springer Nature 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 - Saretzki, Charlotte A1 - Bergmann, Ole A1 - Dahmann, Peter A1 - Janser, Frank A1 - Keimer, Jona A1 - Machado, Patricia A1 - Morrison, Audry A1 - Page, Henry A1 - Pluta, Emil A1 - Stübing, Felix A1 - Küpper, Thomas T1 - Are small airplanes safe with regards to COVID-19 transmission? JF - Journal of Travel Medicine Y1 - 2021 U6 - https://doi.org/10.1093/jtm/taab105 SN - 1708-8305 VL - 28 IS - 7 PB - Oxford University Press CY - Oxford 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 - Salpati, Laurent A1 - Chu, Xiaoyan A1 - Chen, Liangfu A1 - Prasad, Bhagwat A1 - Dallas, Shannon A1 - Evers, Raymond A1 - Mamaril-Fishman, Donna A1 - Geier, Ethan G. A1 - Kehler, Jonathan A1 - Kunta, Jeevan A1 - Mezler, Mario A1 - Laplanche, Loic A1 - Pang, Jodie A1 - Soars, Matthew G. A1 - Unadkat, Jashvant D. A1 - van Waterschoot, Robert A.B. A1 - Yabut, Jocelyn A1 - Schinkel, Alfred H. A1 - Scheer, Nico A1 - Rode, Anja T1 - Evaluation of organic anion transporting polypeptide 1B1 and 1B3 humanized mice as a translational model to study the pharmacokinetics of statins JF - Drug Metabolism and Disposition N2 - Organic anion transporting polypeptide (Oatp) 1a/1b knockout and OATP1B1 and -1B3 humanized mouse models are promising tools for studying the roles of these transporters in drug disposition. Detailed characterization of these models will help to better understand their utility for predicting clinical outcomes. To advance this approach, we carried out a comprehensive analysis of these mouse lines by evaluating the compensatory changes in mRNA expression, quantifying the amounts of OATP1B1 and -1B3 protein by liquid chromatography–tandem mass spectrometry, and studying the active uptake in isolated hepatocytes and the pharmacokinetics of some prototypical substrates including statins. Major outcomes from these studies were 1) mostly moderate compensatory changes in only a few genes involved in drug metabolism and disposition, 2) a robust hepatic expression of OATP1B1 and -1B3 proteins in the respective humanized mouse models, and 3) functional activities of the human transporters in hepatocytes isolated from the humanized models with several substrates tested in vitro and with pravastatin in vivo. However, the expression of OATP1B1 and -1B3 in the humanized models did not significantly alter liver or plasma concentrations of rosuvastatin and pitavastatin compared with Oatp1a/1b knockout controls under the conditions used in our studies. Hence, although the humanized OATP1B1 and -1B3 mice showed in vitro and/or in vivo functional activity with some statins, further characterization of these models is required to define their potential use and limitations in the prediction of drug disposition and drug-drug interactions in humans. Y1 - 2014 U6 - https://doi.org/10.1124/dmd.114.057976 SN - 1521-009X VL - 42 IS - 8 SP - 1301 EP - 1313 PB - ASPET CY - Bethesda, Md. ER - TY - JOUR A1 - Welden, Melanie A1 - Poghossian, Arshak A1 - Vahidpour, Farnoosh A1 - Wendlandt, Tim A1 - Keusgen, Michael A1 - Wege, Christina A1 - Schöning, Michael Josef T1 - Towards multi-analyte detection with field-effect capacitors modified with tobacco mosaic virus bioparticles as enzyme nanocarriers JF - Biosensors N2 - Utilizing an appropriate enzyme immobilization strategy is crucial for designing enzyme-based biosensors. Plant virus-like particles represent ideal nanoscaffolds for an extremely dense and precise immobilization of enzymes, due to their regular shape, high surface-to-volume ratio and high density of surface binding sites. In the present work, tobacco mosaic virus (TMV) particles were applied for the co-immobilization of penicillinase and urease onto the gate surface of a field-effect electrolyte-insulator-semiconductor capacitor (EISCAP) with a p-Si-SiO₂-Ta₂O₅ layer structure for the sequential detection of penicillin and urea. The TMV-assisted bi-enzyme EISCAP biosensor exhibited a high urea and penicillin sensitivity of 54 and 85 mV/dec, respectively, in the concentration range of 0.1–3 mM. For comparison, the characteristics of single-enzyme EISCAP biosensors modified with TMV particles immobilized with either penicillinase or urease were also investigated. The surface morphology of the TMV-modified Ta₂O₅-gate was analyzed by scanning electron microscopy. Additionally, the bi-enzyme EISCAP was applied to mimic an XOR (Exclusive OR) enzyme logic gate. KW - urease KW - enzyme-logic gate KW - bi-enzyme biosensor KW - capacitive field-effect sensor KW - tobacco mosaic virus (TMV) KW - penicillinase Y1 - 2022 U6 - https://doi.org/10.3390/bios12010043 SN - 2079-6374 N1 - This article belongs to the Special Issue "Biosensors: 10th Anniversary Feature Papers" VL - 12 IS - 1 PB - MDPI CY - Basel 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 - Finger, Felix A1 - Braun, Carsten A1 - Bil, Cees T1 - Impact of electric propulsion technology and mission requirements on the performance of VTOL UAVs JF - CEAS Aeronautical Journal N2 - One of the engineering challenges in aviation is the design of transitioning vertical take-off and landing (VTOL) aircraft. Thrust-borne flight implies a higher mass fraction of the propulsion system, as well as much increased energy consumption in the take-off and landing phases. This mass increase is typically higher for aircraft with a separate lift propulsion system than for aircraft that use the cruise propulsion system to support a dedicated lift system. However, for a cost–benefit trade study, it is necessary to quantify the impact the VTOL requirement and propulsion configuration has on aircraft mass and size. For this reason, sizing studies are conducted. This paper explores the impact of considering a supplemental electric propulsion system for achieving hovering flight. Key variables in this study, apart from the lift system configuration, are the rotor disk loading and hover flight time, as well as the electrical systems technology level for both batteries and motors. Payload and endurance are typically used as the measures of merit for unmanned aircraft that carry electro-optical sensors, and therefore the analysis focuses on these particular parameters. Y1 - 2018 U6 - https://doi.org/10.1007/s13272-018-0352-x SN - 1869-5582 print SN - 1869-5590 online VL - 10 IS - 3 SP - 843 PB - Springer ER - TY - JOUR A1 - Lempiäinen, Harri A1 - Couttet, Philippe A1 - Bolognani, Federico A1 - Müller, Arne A1 - Dubost, Valérie A1 - Luisier, Raphaëlle A1 - Rio-Espinola, Alberto del A1 - Vitry, Veronique A1 - Unterberger, Elif B. A1 - Thomson, John P. A1 - Treindl, Fridolin A1 - Metzger, Ute A1 - Wrzodek, Clemens A1 - Hahne, Florian A1 - Zollinger, Tulipan A1 - Brasa, Sarah A1 - Kalteis, Magdalena A1 - Marcellin, Magali A1 - Giudicelli, Fanny A1 - Braeuning, Albert A1 - Morawiec, Laurent A1 - Zamurovic, Natasa A1 - Längle, Ulrich A1 - Scheer, Nico A1 - Schübeler, Dirk A1 - Goodman, Jay A1 - Chibout, Salah-Dine A1 - Marlowe, Jennifer A1 - Theil, Dietlinde A1 - Heard, David J. A1 - Grenet, Olivier A1 - Zell, Andreas A1 - Templin, Markus F. A1 - Meehan, Richard R. A1 - Wolf, Roland C. A1 - Elcombe, Clifford R. A1 - Schwarz, Michael A1 - Moulin, Pierre A1 - Terranova, Rémi A1 - Moggs, Jonathan G. T1 - Identification of Dlk1-Dio3 imprinted gene cluster non-coding RNAs as novel candidate biomarkers for liver tumor promotion JF - Toxicological Sciences N2 - The molecular events during nongenotoxic carcinogenesis and their temporal order are poorly understood but thought to include long-lasting perturbations of gene expression. Here, we have investigated the temporal sequence of molecular and pathological perturbations at early stages of phenobarbital (PB) mediated liver tumor promotion in vivo. Molecular profiling (mRNA, microRNA [miRNA], DNA methylation, and proteins) of mouse liver during 13 weeks of PB treatment revealed progressive increases in hepatic expression of long noncoding RNAs and miRNAs originating from the Dlk1-Dio3 imprinted gene cluster, a locus that has recently been associated with stem cell pluripotency in mice and various neoplasms in humans. PB induction of the Dlk1-Dio3 cluster noncoding RNA (ncRNA) Meg3 was localized to glutamine synthetase-positive hypertrophic perivenous hepatocytes, sug- gesting a role for β-catenin signaling in the dysregulation of Dlk1-Dio3 ncRNAs. The carcinogenic relevance of Dlk1-Dio3 locus ncRNA induction was further supported by in vivo genetic dependence on constitutive androstane receptor and β-catenin pathways. Our data identify Dlk1-Dio3 ncRNAs as novel candidate early biomarkers for mouse liver tumor promotion and provide new opportunities for assessing the carcinogenic potential of novel compounds. Y1 - 2012 U6 - https://doi.org/10.1093/toxsci/kfs303 SN - 1094-2025 VL - 131 IS - 2 SP - 375 EP - 386 PB - Oxford University Press CY - Oxford 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 - Pourshahidi, Ali Mohammad A1 - Achtsnicht, Stefan A1 - Offenhäusser, Andreas A1 - Krause, Hans-Joachim ED - Offenhäusser, Andreas T1 - Frequency Mixing Magnetic Detection Setup Employing Permanent Ring Magnets as a Static Offset Field Source JF - Sensors N2 - Frequency mixing magnetic detection (FMMD) has been explored for its applications in fields of magnetic biosensing, multiplex detection of magnetic nanoparticles (MNP) and the determination of core size distribution of MNP samples. Such applications rely on the application of a static offset magnetic field, which is generated traditionally with an electromagnet. Such a setup requires a current source, as well as passive or active cooling strategies, which directly sets a limitation based on the portability aspect that is desired for point of care (POC) monitoring applications. In this work, a measurement head is introduced that involves the utilization of two ring-shaped permanent magnets to generate a static offset magnetic field. A steel cylinder in the ring bores homogenizes the field. By variation of the distance between the ring magnets and of the thickness of the steel cylinder, the magnitude of the magnetic field at the sample position can be adjusted. Furthermore, the measurement setup is compared to the electromagnet offset module based on measured signals and temperature behavior. KW - magnetic sensors KW - biosensors KW - frequency mixing magnetic detection KW - magnetic nanoparticles Y1 - 2022 U6 - https://doi.org/10.3390/s22228776 SN - 1424-8220 VL - 22 IS - 22 PB - MDPI CY - Basel ER - TY - JOUR A1 - Savitskaya, Irina A1 - Zhantlessova, Sirina A1 - Kistaubayeva, Aida A1 - Ignatova, Ludmila A1 - Shokatayeva, Dina A1 - Sinyavsky, Yuriy A1 - Kushugulova, Almagul A1 - Digel, Ilya T1 - Prebiotic cellulose–pullulan matrix as a “vehicle” for probiotic biofilm delivery to the host large intestine JF - Polymers N2 - This study describes the development of a new combined polysaccharide-matrix-based technology for the immobilization of Lactobacillus rhamnosus GG (LGG) bacteria in biofilm form. The new composition allows for delivering the bacteria to the digestive tract in a manner that improves their robustness compared with planktonic cells and released biofilm cells. Granules consisting of a polysaccharide matrix with probiotic biofilms (PMPB) with high cell density (>9 log CFU/g) were obtained by immobilization in the optimized nutrient medium. Successful probiotic loading was confirmed by fluorescence microscopy and scanning electron microscopy. The developed prebiotic polysaccharide matrix significantly enhanced LGG viability under acidic (pH 2.0) and bile salt (0.3%) stress conditions. Enzymatic extract of feces, mimicking colon fluid in terms of cellulase activity, was used to evaluate the intestinal release of probiotics. PMPB granules showed the ability to gradually release a large number of viable LGG cells in the model colon fluid. In vivo, the oral administration of PMPB granules in rats resulted in the successful release of probiotics in the colon environment. The biofilm-forming incubation method of immobilization on a complex polysaccharide matrix tested in this study has shown high efficacy and promising potential for the development of innovative biotechnologies. KW - immobilization KW - prebiotic KW - bacterial cellulose KW - biofilms KW - Lactobacillus rhamnosus GG Y1 - 2023 U6 - https://doi.org/10.3390/polym16010030 N1 - This article belongs to the Section "Polymer Composites and Nanocomposites" IS - 16(1) PB - MDPI CY - Basel ER - TY - JOUR A1 - Henderson, Colin J. A1 - Mclaughlin, Lesley A. A1 - Scheer, Nico A1 - Stanley, Lesley A. A1 - Wolf, C. Roland T1 - Cytochrome b5 Is a Major Determinant of Human Cytochrome P450 CYP2D6 and CYP3A4 Activity In Vivo s JF - Molecular Pharmacology Y1 - 2015 U6 - https://doi.org/10.1124/mol.114.097394 SN - 1521-0111 VL - 87 IS - 4 SP - 733 EP - 739 PB - ASPET CY - Bethesda ER - TY - JOUR A1 - Kapelyukh, Yury A1 - Henderson, Colin James A1 - Scheer, Nico A1 - Rode, Anja A1 - Wolf, Charles Roland T1 - Defining the contribution of CYP1A1 and CYP1A2 to drug metabolism using humanized CYP1A1/1A2 and Cyp1a1/Cyp1a2 KO mice JF - Drug Metabolism and Disposition Y1 - 2019 U6 - https://doi.org/10.1124/dmd.119.087718 IS - Early view ER - TY - JOUR A1 - von Knobelsdorf-Brenkenhoff, Florian A1 - Frauenrath, Tobias A1 - Prothmann, Marcel A1 - Dieringer, Matthias A. A1 - Hezel, Fabian A1 - Renz, Wolfgang A1 - Kretschel, Kerstin A1 - Niendorf, Thoralf A1 - Schulz-Menger, Jeanette T1 - Cardiac chamber quantification using magnetic resonance imaging at 7 Tesla—a pilot study N2 - Objectives Interest in cardiovascular magnetic resonance (CMR) at 7 T is motivated by the expected increase in spatial and temporal resolution, but the method is technically challenging. We examined the feasibility of cardiac chamber quantification at 7 T. Methods A stack of short axes covering the left ventricle was obtained in nine healthy male volunteers. At 1.5 T, steady-state free precession (SSFP) and fast gradient echo (FGRE) cine imaging with 7 mm slice thickness (STH) were used. At 7 T, FGRE with 7 mm and 4 mm STH were applied. End-diastolic volume, end-systolic volume, ejection fraction and mass were calculated. Results All 7 T examinations provided excellent blood/myocardium contrast for all slice directions. No significant difference was found regarding ejection fraction and cardiac volumes between SSFP at 1.5 T and FGRE at 7 T, while volumes obtained from FGRE at 1.5 T were underestimated. Cardiac mass derived from FGRE at 1.5 and 7 T was larger than obtained from SSFP at 1.5 T. Agreement of volumes and mass between SSFP at 1.5 T and FGRE improved for FGRE at 7 T when combined with an STH reduction to 4 mm. Conclusions This pilot study demonstrates that cardiac chamber quantification at 7 T using FGRE is feasible and agrees closely with SSFP at 1.5 T. Y1 - 2010 U6 - https://doi.org/10.1007/s00330-010-1888-2 SN - 0938-7994 VL - 20 SP - 2844 EP - 2852 PB - Springer CY - Berlin, Heidelberg ER - TY - JOUR A1 - Falkenberg, Fabian A1 - Bott, Michael A1 - Bongaerts, Johannes A1 - Siegert, Petra T1 - Phylogenetic survey of the subtilase family and a data-mining-based search for new subtilisins from Bacillaceae JF - Frontiers in Microbiology N2 - The subtilase family (S8), a member of the clan SB of serine proteases are ubiquitous in all kingdoms of life and fulfil different physiological functions. Subtilases are divided in several groups and especially subtilisins are of interest as they are used in various industrial sectors. Therefore, we searched for new subtilisin sequences of the family Bacillaceae using a data mining approach. The obtained 1,400 sequences were phylogenetically classified in the context of the subtilase family. This required an updated comprehensive overview of the different groups within this family. To fill this gap, we conducted a phylogenetic survey of the S8 family with characterised holotypes derived from the MEROPS database. The analysis revealed the presence of eight previously uncharacterised groups and 13 subgroups within the S8 family. The sequences that emerged from the data mining with the set filter parameters were mainly assigned to the subtilisin subgroups of true subtilisins, high-alkaline subtilisins, and phylogenetically intermediate subtilisins and represent an excellent source for new subtilisin candidates. Y1 - 2022 U6 - https://doi.org/10.3389/fmicb.2022.1017978 SN - 1664-302X VL - 2022 IS - 13 PB - Frontiers CY - Lausanne ER - TY - JOUR A1 - Danho, Waleed A1 - Naithani, Vinod K. A1 - Sasaki, André N. A1 - Föhles, Joseph A1 - Berndt, Heinz A1 - [u.a.], T1 - Human proinsulin, VII : synthesis of two protected peptides corresponding to the sequences 1—45 and 46—86 of the prohormone JF - Hoppe-Seyler's Zeitschrift für physiologische Chemie Y1 - 1980 U6 - https://doi.org/10.1515/bchm2.1980.361.1.857 SN - 1437-4315 SN - 0018-4888 VL - 361 IS - 1 SP - 857 EP - 863 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 - Welden, Melanie A1 - Severins, Robin A1 - Poghossian, Arshak A1 - Wege, Christina A1 - Bongaerts, Johannes A1 - Siegert, Petra A1 - Keusgen, Michael A1 - Schöning, Michael Josef T1 - Detection of acetoin and diacetyl by a tobacco mosaic virus-assisted field-effect biosensor JF - Chemosensors N2 - Acetoin and diacetyl have a major impact on the flavor of alcoholic beverages such as wine or beer. Therefore, their measurement is important during the fermentation process. Until now, gas chromatographic techniques have typically been applied; however, these require expensive laboratory equipment and trained staff, and do not allow for online monitoring. In this work, a capacitive electrolyte–insulator–semiconductor sensor modified with tobacco mosaic virus (TMV) particles as enzyme nanocarriers for the detection of acetoin and diacetyl is presented. The enzyme acetoin reductase from Alkalihalobacillus clausii DSM 8716ᵀ is immobilized via biotin–streptavidin affinity, binding to the surface of the TMV particles. The TMV-assisted biosensor is electrochemically characterized by means of leakage–current, capacitance–voltage, and constant capacitance measurements. In this paper, the novel biosensor is studied regarding its sensitivity and long-term stability in buffer solution. Moreover, the TMV-assisted capacitive field-effect sensor is applied for the detection of diacetyl for the first time. The measurement of acetoin and diacetyl with the same sensor setup is demonstrated. Finally, the successive detection of acetoin and diacetyl in buffer and in diluted beer is studied by tuning the sensitivity of the biosensor using the pH value of the measurement solution. Y1 - 2022 U6 - https://doi.org/10.3390/chemosensors10060218 SN - 2227-9040 N1 - This article belongs to the Special Issue "Nanostructured Devices for Biochemical Sensing" VL - 10 IS - 6 PB - MDPI CY - Basel ER - TY - JOUR A1 - Karschuck, Tobias A1 - Kaulen, Corinna A1 - Poghossian, Arshak A1 - Wagner, Patrick H. A1 - Schöning, Michael Josef T1 - Gold nanoparticle-modified capacitive field-effect sensors: Studying the surface density of nanoparticles and coupling of charged polyelectrolyte macromolecules JF - Electrochemical Science Advances N2 - The coupling of ligand-stabilized gold nanoparticles with field-effect devices offers new possibilities for label-free biosensing. In this work, we study the immobilization of aminooctanethiol-stabilized gold nanoparticles (AuAOTs) on the silicon dioxide surface of a capacitive field-effect sensor. The terminal amino group of the AuAOT is well suited for the functionalization with biomolecules. The attachment of the positively-charged AuAOTs on a capacitive field-effect sensor was detected by direct electrical readout using capacitance-voltage and constant capacitance measurements. With a higher particle density on the sensor surface, the measured signal change was correspondingly more pronounced. The results demonstrate the ability of capacitive field-effect sensors for the non-destructive quantitative validation of nanoparticle immobilization. In addition, the electrostatic binding of the polyanion polystyrene sulfonate to the AuAOT-modified sensor surface was studied as a model system for the label-free detection of charged macromolecules. Most likely, this approach can be transferred to the label-free detection of other charged molecules such as enzymes or antibodies. KW - polystyrene sulfonate KW - gold nanoparticles KW - field-effect sensor KW - detection of charged macromolecules KW - capacitive EIS sensor Y1 - 2021 U6 - https://doi.org/10.1002/elsa.202100179 SN - 0938-5193 VL - 2 IS - 5 PB - Wiley-VCH CY - Weinheim 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 - Naithani, V. K A1 - Klostermeyer, Henning A1 - Lange, H. R. A1 - [u.a.], A1 - Berndt, Heinz A1 - [u.a.], T1 - Preparation of peptide derivatives for porcine proinsulin-synthesis JF - Biological Chemistry Y1 - 1971 U6 - https://doi.org/10.1515/bchm2.1971.352.1.1 SN - 1437-4315 VL - 352 IS - 1 SP - 2 EP - 3 PB - De Gruyter 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 - Hackl, Michael A1 - Buess, Eduard A1 - Kammerlohr, Sandra A1 - Nacov, Julia A1 - Staat, Manfred A1 - Leschinger, Tim A1 - Müller, Lars P. A1 - Wegmann, Kilian T1 - A "comma sign"-directed subscapularis repair in anterosuperior rotator cuff tears yields biomechanical advantages in a cadaveric model JF - The american journal of sports medicine N2 - Background: Additional stabilization of the “comma sign” in anterosuperior rotator cuff repair has been proposed to provide biomechanical benefits regarding stability of the repair. Purpose: This in vitro investigation aimed to investigate the influence of a comma sign–directed reconstruction technique for anterosuperior rotator cuff tears on the primary stability of the subscapularis tendon repair. Study Design: Controlled laboratory study. Methods: A total of 18 fresh-frozen cadaveric shoulders were used in this study. Anterosuperior rotator cuff tears (complete full-thickness tear of the supraspinatus and subscapularis tendons) were created, and supraspinatus repair was performed with a standard suture bridge technique. The subscapularis was repaired with either a (1) single-row or (2) comma sign technique. A high-resolution 3D camera system was used to analyze 3-mm and 5-mm gap formation at the subscapularis tendon-bone interface upon incremental cyclic loading. Moreover, the ultimate failure load of the repair was recorded. A Mann-Whitney test was used to assess significant differences between the 2 groups. Results: The comma sign repair withstood significantly more loading cycles than the single-row repair until 3-mm and 5-mm gap formation occurred (P≤ .047). The ultimate failure load did not reveal any significant differences when the 2 techniques were compared (P = .596). Conclusion: The results of this study show that additional stabilization of the comma sign enhanced the primary stability of subscapularis tendon repair in anterosuperior rotator cuff tears. Although this stabilization did not seem to influence the ultimate failure load, it effectively decreased the micromotion at the tendon-bone interface during cyclic loading. Clinical Relevance: The proposed technique for stabilization of the comma sign has shown superior biomechanical properties in comparison with a single-row repair and might thus improve tendon healing. Further clinical research will be necessary to determine its influence on the functional outcome. Y1 - 2021 U6 - https://doi.org/10.1177/03635465211031506 SN - 1552-3365 SN - 0363-5465 VL - 49 IS - 12 SP - 3212 EP - 3217 PB - Sage CY - London 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 - Ojovan, Michael I. A1 - Steinmetz, Hans-Jürgen T1 - Approaches to Disposal of Nuclear Waste JF - Energies N2 - We present a concise mini overview on the approaches to the disposal of nuclear waste currently used or deployed. The disposal of nuclear waste is the end point of nuclear waste management (NWM) activities and is the emplacement of waste in an appropriate facility without the intention to retrieve it. The IAEA has developed an internationally accepted classification scheme based on the end points of NWM, which is used as guidance. Retention times needed for safe isolation of waste radionuclides are estimated based on the radiotoxicity of nuclear waste. Disposal facilities usually rely on a multi-barrier defence system to isolate the waste from the biosphere, which comprises the natural geological barrier and the engineered barrier system. Disposal facilities could be of a trench type, vaults, tunnels, shafts, boreholes, or mined repositories. A graded approach relates the depth of the disposal facilities’ location with the level of hazard. Disposal practices demonstrate the reliability of nuclear waste disposal with minimal expected impacts on the environment and humans. KW - borehole disposal KW - geological disposal KW - disposal facility KW - retention time KW - nuclear waste Y1 - 2022 U6 - https://doi.org/10.3390/en15207804 SN - 1996-1073 N1 - This article belongs to the Special Issue "Treatment of Radioactive Waste and Sustainability Energy" VL - 15 IS - 20 PB - MDPI CY - Basel 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 - Biewendt, Marcel A1 - Blaschke, Florian A1 - Böhnert, Arno T1 - Motivational factors in organisational change JF - SocioEconomic Challenges N2 - The presented paper gives an overview of the most important and most common theories and concepts from the economic field of organisational change and is also enriched with quantitative publication data, which underlines the relevance of the topic. In particular, the topic presented is interwoven in an interdisciplinary way with economic psychological models, which are underpinned within the models with content from leading scholars in the field. The pace of change in companies is accelerating, as is technological change in our society. Adaptations of the corporate structure, but also of management techniques and tasks, are therefore indispensable. This includes not only the right approaches to employee motivation, but also the correct use of intrinsic and extrinsic motivational factors. Based on the hypothesis put forward by the scientist and researcher Rollinson in his book “Organisational behaviour and analysis” that managers believe motivational resources are available at all times, socio-economic and economic psychological theories are contrasted here in order to critically examine this statement. In addition, a fictitious company was created as a model for this work in order to illustrate the effects of motivational deficits in practice. In this context, the theories presented are applied to concrete problems within the model and conclusions are drawn about their influence and applicability. This led to the conclusion that motivation is a very individual challenge for each employee, which requires adapted and personalised approaches. On the other hand, the recommendations for action for supervisors in the case of motivation deficits also cannot be answered in a blanket manner, but can only be solved with the help of professional, expert-supported processing due to the economic-psychological realities of motivation. Identifying, analysing and remedying individual employee motivation deficits is, according to the authors, a problem and a challenge of great importance, especially in the context of rapidly changing ecosystems in modern companies, as motivation also influences other factors such as individual productivity. The authors therefore conclude that good motivation through the individual and customised promotion and further training of employees is an important point for achieving important corporate goals in order to remain competitive on the one hand and to create a productive and pleasant working environment on the other. KW - business culture KW - management KW - motivation KW - change Y1 - 2021 U6 - https://doi.org/10.21272/sec.5(3).15-27.2021 SN - 2520-6214 VL - 5 IS - 3 SP - 15 EP - 27 PB - ARMG CY - Sumy ER - TY - JOUR A1 - Hüning, Felix A1 - Heuermann, Holger A1 - Wache, Franz-Josef A1 - Jajo, Rami Audisho T1 - A new wireless sensor interface using dual-mode radio JF - Journal of Sensors and Sensor Systems : JSSS N2 - The integration of sensors is one of the major tasks in embedded, control and “internet of things” (IoT) applications. For the integration mainly digital interfaces are used, starting from rather simple pulse-width modulation (PWM) interface to more complex interfaces like CAN (Controller Area Network). Even though these interfaces are tethered by definition, a wireless realization is highly welcome in many applications to reduce cable and connector cost, increase the flexibility and realize new emerging applications like wireless control systems. Currently used wireless solutions like Bluetooth, WirelessHART or IO-Link Wireless use dedicated communication standards and corresponding higher protocol layers to realize the wireless communication. Due to the complexity of the communication and the protocol handling, additional latency and jitter are introduced to the data communication that can meet the requirements for many applications. Even though tunnelling of other bus data like CAN data is generally also possible the latency and jitter prevent the tunnelling from being transparent for the bus system. Therefore a new basic technology based on dual-mode radio is used to realize a wireless communication on the physical layer only, enabling a reliable and real-time data transfer. As this system operates on the physical layer it is independent of any higher layers of the OSI (open systems interconnection) model. Hence it can be used for several different communication systems to replace the tethered physical layer. A prototype is developed and tested for real-time wireless PWM, SENT (single-edge nibble transmission) and CAN data transfer with very low latency and jitter. Y1 - 2018 U6 - https://doi.org/10.5194/jsss-7-507-2018 VL - Volume 7 IS - 2 SP - 507 EP - 515 PB - Copernicus Publ. CY - Göttingen ER - TY - JOUR A1 - Luft, Angela A1 - Luft, Nils A1 - Arntz, Kristian T1 - A basic description logic for service-oriented architecture in factory planning and operational control in the age of industry 4.0 JF - Applied Sciences N2 - Manufacturing companies across multiple industries face an increasingly dynamic and unpredictable environment. This development can be seen on both the market and supply side. To respond to these challenges, manufacturing companies must implement smart manufacturing systems and become more flexible and agile. The flexibility in operational planning regarding the scheduling and sequencing of customer orders needs to be increased and new structures must be implemented in manufacturing systems’ fundamental design as they constitute much of the operational flexibility available. To this end, smart and more flexible solutions for production planning and control (PPC) are developed. However, scheduling or sequencing is often only considered isolated in a predefined stable environment. Moreover, their orientation on the fundamental logic of the existing IT solutions and their applicability in a dynamic environment is limited. This paper presents a conceptual model for a task-based description logic that can be applied to factory planning, technology planning, and operational control. By using service-oriented architectures, the goal is to generate smart manufacturing systems. The logic is designed to allow for easy and automated maintenance. It is compatible with the existing resource and process allocation logic across operational and strategic factory and production planning. KW - manufacturing data model KW - production planning and control KW - manufacturing flexibility KW - technology planning KW - SOA KW - service-oriented architectures KW - factory planning Y1 - 2023 U6 - https://doi.org/10.3390/app13137610 SN - 2076-3417 N1 - This article belongs to the Special Issue "Smart Industrial System" VL - 2023 IS - 13 PB - MDPI CY - Basel ER - TY - JOUR A1 - Dobbertin, Matthias A1 - Eilmann, Britta A1 - Bleuler, Peter A1 - Giuggiola, Arnaud A1 - Graf Pannatier, Elisabeth A1 - Landolt, Werner A1 - Schleppi, Patrick A1 - Rigling, Andreas T1 - Effect of irrigation on needle morphology, shoot and stem growth in a drought-exposed Pinus sylvestris forest JF - Tree Physiology N2 - In Valais, Switzerland, Scots pines (Pinus sylvestris L.) are declining, mainly following drought. To assess the impact of drought on tree growth and survival, an irrigation experiment was initiated in 2003 in a mature pine forest, approximately doubling the annual precipitation. Tree crown transparency (lack of foliage) and leaf area index (LAI) were annually assessed. Seven irrigated and six control trees were felled in 2006, and needles, stem discs and branches were taken for growth analysis. Irrigation in 2004 and 2005, both with below-average precipitation, increased needle size, area and mass, stem growth and, with a 1-year delay, shoot length. This led to a relative decrease in tree crown transparency (−14%) and to an increase in stand LAI (+20%). Irrigation increased needle length by 70%, shoot length by 100% and ring width by 120%, regardless of crown transparency. Crown transparency correlated positively with mean needle size, shoot length and ring width and negatively with specific leaf area. Trees with high crown transparency (low growth, short needles) experienced similar increases in needle mass and growth with irrigation than trees with low transparency (high growth, long needles), indicating that seemingly declining trees were able to ‘recover’ when water supply became sufficient. A simple drought index before and during the irrigation explained most of the variation found in the parameters for both irrigated and control trees. Y1 - 2010 U6 - https://doi.org/10.1093/treephys/tpp123 SN - 1758-4469 (Online) SN - 0829-318X (Print) VL - 30 IS - 3 SP - 346 EP - 360 PB - Oxford University Press CY - Oxford ER - TY - JOUR A1 - Heinrichs, Uwe A1 - Utting, Jane F. A1 - Frauenrath, Tobias A1 - Hezel, Fabian A1 - Krombach, Gabriele A. A1 - Hodenius, Michael A. J. A1 - Kozerke, Sebastian A1 - Niendorf, Thoralf T1 - Myocardial T2 mapping free of distortion using susceptibility-weighted fast spin-echo imaging: A feasibility study at 1.5 T and 3.0 T JF - Magnetic Resonance in Medicine N2 - This study demonstrates the feasibility of applying free-breathing, cardiac-gated, susceptibility-weighted fast spin-echo imaging together with black blood preparation and navigator-gated respiratory motion compensation for anatomically accurate T₂ mapping of the heart. First, T₂ maps are presented for oil phantoms without and with respiratory motion emulation (T₂ = (22.1 ± 1.7) ms at 1.5 T and T₂ = (22.65 ± 0.89) ms at 3.0 T). T₂ relaxometry of a ferrofluid revealed relaxivities of R2 = (477.9 ± 17) mM⁻¹s⁻¹ and R2 = (449.6 ± 13) mM⁻¹s⁻¹ for UFLARE and multiecho gradient-echo imaging at 1.5 T. For inferoseptal myocardial regions mean T₂ values of 29.9 ± 6.6 ms (1.5 T) and 22.3 ± 4.8 ms (3.0 T) were estimated. For posterior myocardial areas close to the vena cava T₂-values of 24.0 ± 6.4 ms (1.5 T) and 15.4 ± 1.8 ms (3.0 T) were observed. The merits and limitations of the proposed approach are discussed and its implications for cardiac and vascular T₂-mapping are considered. Y1 - 2009 U6 - https://doi.org/10.1002/mrm.22054 SN - 1522-2594 VL - 62 IS - 3 SP - 822 EP - 828 PB - Wiley-Liss CY - New York ER - TY - JOUR A1 - Ferrein, Alexander A1 - Meyer, Thomas T1 - A Brief Overview of Artificial Intelligence in South Africa JF - AI Magazine N2 - South Africa in recent years is the establishment of a number of research hubs involved in AI activities ranging from mobile robotics and computational intelligence, to knowledge representation and reasoning, and human language technologies. In this survey we take the reader through a quick tour of the research being conducted at these hubs, and touch on an initiative to maintain and extend the current level of interest in AI research in the country. Y1 - 2012 U6 - https://doi.org/10.1609/aimag.v33i1.2357 SN - 0738-4602 VL - 33 IS - 1 SP - 99 EP - 101 PB - AAAI CY - Menlo Park ER - TY - JOUR A1 - Weemstra, Monique A1 - Eilmann, Britta A1 - Sass-Klaassen, Ute G. W. A1 - Sterck, Frank J. T1 - Summer droughts limit tree growth across 10 temperate species on a productive forest site JF - Forest Ecology and Management Y1 - 2013 U6 - https://doi.org/doi:10.1016/j.foreco.2013.06.007 SN - 0378-1127 (Print) SN - 1872-7042 (Online) VL - 2013 IS - 306 SP - 142 EP - 149 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Anik, Sabri A1 - Frohberg, Martin G. T1 - Thermodynamics and solubility of oxygen in liquid bismuth-lead and bismuth-antimony alloys JF - Berichte der Bunsengesellschaft für physikalische Chemie Y1 - 1987 SN - 0940-483X SN - 0005-9021 VL - 91 IS - 7 SP - 790 EP - 794 ER - TY - JOUR A1 - Frohberg, Martin G. A1 - Anik, Sabri T1 - The application of a quadi-chemical lattice model to binary metallic solvents containing oxygen in higher concentrations JF - Zeitschrift für Metallkunde Y1 - 1983 SN - 0044-3093 VL - 74 IS - 10 SP - 665 EP - 666 ER - TY - JOUR A1 - Feichtinger, Linda M. A1 - Eilmann, Britta A1 - Buchmann, Nina A1 - Rigling, Andreas T1 - Growth adjustments of conifers to drought and to century-long irrigation JF - Forest Ecology and Management N2 - Our knowledge on tree responses to drought is mainly based on short-term manipulation experiments which do not capture any possible long-term adjustments in this response. Therefore, historical water channels in inner-Alpine dry valleys were used as century-long irrigation experiments to investigate adjustments in tree growth to contrasting water supply. This involved quantifying the tree-ring growth of irrigated and non-irrigated (control) Scots pine (Pinus sylvestris L.) in Valais (Switzerland), as well as European larch (Larix decidua Mill.) and black pine (Pinus nigra Arnold) in Vinschgau (Italy). Furthermore, the adjustments in radial growth of Scots pine and European larch to an abrupt stop in irrigation were analyzed. Irrigation promoted the radial growth of all tree species investigated compared to the control: (1) directly through increased soil water availability, and (2) indirectly through increased soil nutrients and humus contents in the irrigated plots. Irrigation led to a full elimination of growth responses to climate for European larch and black pine, but not for Scots pine, which might become more sensitive to drought with increasing tree size in Valais. For the control trees, the response of the latewood increment to water availability in July/August has decreased in recent decades for all species, but increased in May for Scots pine only. The sudden irrigation stop caused a drop in radial growth to a lower level for Scots pine or similar level for larch compared to the control for up to ten years. However, both tree species were then able to adjust to the new conditions and subsequently grew with similar (Scots pine) or even higher growth rates (larch) than the control. To estimate the impact of climate change on future forest development, the duration of manipulation experiments should be on longer time scales in order to capture adjustment processes and feedback mechanisms of forest ecosystems. Y1 - 2014 U6 - https://doi.org/10.1016/j.foreco.2014.08.008 SN - 1872-7042 (Online) SN - 0378-1127 (Print) VL - 2014 IS - 334 SP - 96 EP - 105 PB - Elsevier CY - Amsterdam ER -