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 - BOOK A1 - Laack, Walter van T1 - Aufruf zum Nachdenken: Corona und neue Kriege – Wie kann die Menschheit überleben? T1 - Call for Reflection: Corona and New Wars – How can Mankind survive? Y1 - 2022 SN - 978-3-936624-56-4 N1 - Dritter Band der Buchreihe “Vorträge & Einsichten – Lectures & Insights” und hier das zweite “Upside-Down-Buch”: Deutsche und englische Version in einem Buch. PB - van Laack GmbH CY - Aachen 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 - 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 - Pourshahidi, Ali Mohammad A1 - Engelmann, Ulrich M. A1 - Offenhäusser, Andreas A1 - Krause, Hans-Joachim T1 - Resolving ambiguities in core size determination of magnetic nanoparticles from magnetic frequency mixing data JF - Journal of Magnetism and Magnetic Materials N2 - Frequency mixing magnetic detection (FMMD) has been widely utilized as a measurement technique in magnetic immunoassays. It can also be used for the characterization and distinction (also known as “colourization”) of different types of magnetic nanoparticles (MNPs) based on their core sizes. In a previous work, it was shown that the large particles contribute most of the FMMD signal. This leads to ambiguities in core size determination from fitting since the contribution of the small-sized particles is almost undetectable among the strong responses from the large ones. In this work, we report on how this ambiguity can be overcome by modelling the signal intensity using the Langevin model in thermodynamic equilibrium including a lognormal core size distribution fL(dc,d0,σ) fitted to experimentally measured FMMD data of immobilized MNPs. For each given median diameter d0, an ambiguous amount of best-fitting pairs of parameters distribution width σ and number of particles Np with R2 > 0.99 are extracted. By determining the samples’ total iron mass, mFe, with inductively coupled plasma optical emission spectrometry (ICP-OES), we are then able to identify the one specific best-fitting pair (σ, Np) one uniquely. With this additional externally measured parameter, we resolved the ambiguity in core size distribution and determined the parameters (d0, σ, Np) directly from FMMD measurements, allowing precise MNPs sample characterization. Y1 - 2022 U6 - https://doi.org/10.1016/j.jmmm.2022.169969 SN - 0304-8853 VL - 563 IS - In progress, Art. No. 169969 PB - Elsevier CY - Amsterdam ER - TY - CHAP A1 - Tran, Ngoc Trinh A1 - Trinh, Tu Luc A1 - Dao, Ngoc Tien A1 - Giap, Van Tan A1 - Truong, Manh Khuyen A1 - Dinh, Thuy Ha A1 - Staat, Manfred T1 - Limit and shakedown analysis of structures under random strength T2 - Proceedings of (NACOME2022) The 11th National Conference on Mechanics, Vol. 1. Solid Mechanics, Rock Mechanics, Artificial Intelligence, Teaching and Training N2 - Direct methods comprising limit and shakedown analysis is a branch of computational mechanics. It plays a significant role in mechanical and civil engineering design. The concept of direct method aims to determinate the ultimate load bearing capacity of structures beyond the elastic range. For practical problems, the direct methods lead to nonlinear convex optimization problems with a large number of variables and onstraints. If strength and loading are random quantities, the problem of shakedown analysis is considered as stochastic programming. This paper presents a method so called chance constrained programming, an effective method of stochastic programming, to solve shakedown analysis problem under random condition of strength. In this our investigation, the loading is deterministic, the strength is distributed as normal or lognormal variables. KW - Reliability of structures KW - Stochastic programming KW - Chance constrained programming KW - Shakedown analysis KW - Limit analysis Y1 - 2022 SN - 978-604-357-084-7 N1 - 11th National Conference on Mechanics (NACOME 2022), December 2-3, 2022, VNU University of Engineering and Technology, Hanoi, Vietnam SP - 510 EP - 518 PB - Nha xuat ban Khoa hoc tu nhien va Cong nghe (Verlag Naturwissenschaft und Technik) CY - Hanoi ER - TY - JOUR A1 - Akimbekov, Nuraly S. A1 - Digel, Ilya A1 - Tastambek, Kuanysh T. A1 - Marat, Adel K. A1 - Turaliyeva, Moldir A. A1 - Kaiyrmanova, Gulzhan K. T1 - Biotechnology of Microorganisms from Coal Environments: From Environmental Remediation to Energy Production JF - Biology N2 - It was generally believed that coal sources are not favorable as live-in habitats for microorganisms due to their recalcitrant chemical nature and negligible decomposition. However, accumulating evidence has revealed the presence of diverse microbial groups in coal environments and their significant metabolic role in coal biogeochemical dynamics and ecosystem functioning. The high oxygen content, organic fractions, and lignin-like structures of lower-rank coals may provide effective means for microbial attack, still representing a greatly unexplored frontier in microbiology. Coal degradation/conversion technology by native bacterial and fungal species has great potential in agricultural development, chemical industry production, and environmental rehabilitation. Furthermore, native microalgal species can offer a sustainable energy source and an excellent bioremediation strategy applicable to coal spill/seam waters. Additionally, the measures of the fate of the microbial community would serve as an indicator of restoration progress on post-coal-mining sites. This review puts forward a comprehensive vision of coal biodegradation and bioprocessing by microorganisms native to coal environments for determining their biotechnological potential and possible applications. Y1 - 2022 U6 - https://doi.org/10.3390/biology11091306 SN - 2079-7737 N1 - This article belongs to the Special Issue "Microbial Ecology and Evolution in Extreme Environments" VL - 11 IS - 9 PB - MDPI CY - Basel ER - TY - GEN A1 - Topcu, Murat A1 - Madabhushi, Gopal Santana Phani A1 - Staat, Manfred T1 - Datasets from FEM Simulations done with COMSOL Multiphysics and Code_Aster N2 - Datasets from FEM Simulations done with COMSOL Multiphysics and Code_Aster for an elastic stress transfer between matrix and fibres having a variable radius. KW - Natural fibres KW - Polymer-matrix composites KW - Biocomposites KW - Stress concentrations KW - Finite element analysis (FEA) Y1 - 2022 U6 - https://doi.org/10.6084/m9.figshare.19333295.v2 ER - TY - JOUR A1 - Thiebes, Anja Lena A1 - Klein, Sarah A1 - Zingsheim, Jonas A1 - Möller, Georg H. A1 - Gürzing, Stefanie A1 - Reddemann, Manuel A. A1 - Behbahani, Mehdi A1 - Cornelissen, Christian G. T1 - Effervescent atomizer as novel cell spray technology to decrease the gas-to-liquid ratio JF - pharmaceutics N2 - Cell spraying has become a feasible application method for cell therapy and tissue engineering approaches. Different devices have been used with varying success. Often, twin-fluid atomizers are used, which require a high gas velocity for optimal aerosolization characteristics. To decrease the amount and velocity of required air, a custom-made atomizer was designed based on the effervescent principle. Different designs were evaluated regarding spray characteristics and their influence on human adipose-derived mesenchymal stromal cells. The arithmetic mean diameters of the droplets were 15.4–33.5 µm with decreasing diameters for increasing gas-to-liquid ratios. The survival rate was >90% of the control for the lowest gas-to-liquid ratio. For higher ratios, cell survival decreased to approximately 50%. Further experiments were performed with the design, which had shown the highest survival rates. After seven days, no significant differences in metabolic activity were observed. The apoptosis rates were not influenced by aerosolization, while high gas-to-liquid ratios caused increased necrosis levels. Tri-lineage differentiation potential into adipocytes, chondrocytes, and osteoblasts was not negatively influenced by aerosolization. Thus, the effervescent aerosolization principle was proven suitable for cell applications requiring reduced amounts of supplied air. This is the first time an effervescent atomizer was used for cell processing. KW - tri-lineage differentiation KW - survival KW - twin-fluid atomizer KW - adipose-derived stromal cells (ASCs) KW - cell atomization KW - cell aerosolization Y1 - 2022 U6 - https://doi.org/10.3390/pharmaceutics14112421 N1 - This article belongs to the Special Issue "Stromal, Stem, Signaling Cells: The Multiple Roles and Applications of Mesenchymal Cells" VL - 14 IS - 11 PB - MDPI CY - Basel ER - TY - BOOK A1 - Laack, Walter van T1 - Greater Than the Entire Universe Y1 - 2022 SN - 978-3-936624-52-6 PB - van Laack GmbH CY - Aachen ER - TY - CHAP A1 - Staat, Manfred A1 - Tran, Ngoc Trinh T1 - Strain based brittle failure criteria for rocks T2 - Proceedings of (NACOME2022) The 11th National Conference on Mechanics, Vol. 1. Solid Mechanics, Rock Mechanics, Artificial Intelligence, Teaching and Training N2 - When confining pressure is low or absent, extensional fractures are typical, with fractures occurring on unloaded planes in rock. These “paradox” fractures can be explained by a phenomenological extension strain failure criterion. In the past, a simple empirical criterion for fracture initiation in brittle rock has been developed. But this criterion makes unrealistic strength predictions in biaxial compression and tension. A new extension strain criterion overcomes this limitation by adding a weighted principal shear component. The weight is chosen, such that the enriched extension strain criterion represents the same failure surface as the Mohr–Coulomb (MC) criterion. Thus, the MC criterion has been derived as an extension strain criterion predicting failure modes, which are unexpected in the understanding of the failure of cohesive-frictional materials. In progressive damage of rock, the most likely fracture direction is orthogonal to the maximum extension strain. The enriched extension strain criterion is proposed as a threshold surface for crack initiation CI and crack damage CD and as a failure surface at peak P. Examples show that the enriched extension strain criterion predicts much lower volumes of damaged rock mass compared to the simple extension strain criterion. KW - Extension fracture KW - Extension strain criterion KW - Mohr–Coulomb criterion KW - Evolution of damage Y1 - 2023 SN - 978-604-357-084-7 N1 - 11th National Conference on Mechanics (NACOME 2022), December 2-3, 2022, VNU University of Engineering and Technology, Hanoi, Vietnam SP - 500 EP - 509 PB - Nha xuat ban Khoa hoc tu nhien va Cong nghe (Verlag Naturwissenschaft und Technik) CY - Hanoi ER - TY - JOUR A1 - Schneider, Jules A1 - Schwabedal, Justus T. C. A1 - Bialonski, Stephan T1 - Schlafspindeln – Funktion, Detektion und Nutzung als Biomarker für die psychiatrische Diagnostik JF - Der Nervenarzt N2 - Hintergrund: Die Schlafspindel ist ein Graphoelement des Elektroenzephalogramms (EEG), das im Leicht- und Tiefschlaf beobachtet werden kann. Veränderungen der Spindelaktivität wurden für verschiedene psychiatrische Erkrankungen beschrieben. Schlafspindeln zeigen aufgrund ihrer relativ konstanten Eigenschaften Potenzial als Biomarker in der psychiatrischen Diagnostik. Methode: Dieser Beitrag liefert einen Überblick über den Stand der Wissenschaft zu Eigenschaften und Funktionen der Schlafspindeln sowie über beschriebene Veränderungen der Spindelaktivität bei psychiatrischen Erkrankungen. Verschiedene methodische Ansätze und Ausblicke zur Spindeldetektion werden hinsichtlich deren Anwendungspotenzial in der psychiatrischen Diagnostik erläutert. Ergebnisse und Schlussfolgerung: Während Veränderungen der Spindelaktivität bei psychiatrischen Erkrankungen beschrieben wurden, ist deren exaktes Potenzial für die psychiatrische Diagnostik noch nicht ausreichend erforscht. Diesbezüglicher Erkenntnisgewinn wird in der Forschung gegenwärtig durch ressourcenintensive und fehleranfällige Methoden zur manuellen oder automatisierten Spindeldetektion ausgebremst. Neuere Detektionsansätze, die auf Deep-Learning-Verfahren basieren, könnten die Schwierigkeiten bisheriger Detektionsmethoden überwinden und damit neue Möglichkeiten für die praktisch KW - Schlafspindeldetektion KW - Psychiatrische Biomarker KW - · Psychiatrische Erkrankungen/Diagnostik KW - Elektroenzephalographie KW - Deep Learning Y1 - 2022 U6 - https://doi.org/10.1007/s00115-022-01340-z SN - 1433-0407 SP - 1 EP - 8 PB - Springer CY - Berlin, Heidelberg ER - TY - CHAP A1 - Gaigall, Daniel T1 - On Consistent Hypothesis Testing In General Hilbert Spaces T2 - Proceedings of the 4th International Conference on Statistics: Theory and Applications (ICSTA’22) N2 - Inference on the basis of high-dimensional and functional data are two topics which are discussed frequently in the current statistical literature. A possibility to include both topics in a single approach is working on a very general space for the underlying observations, such as a separable Hilbert space. We propose a general method for consistently hypothesis testing on the basis of random variables with values in separable Hilbert spaces. We avoid concerns with the curse of dimensionality due to a projection idea. We apply well-known test statistics from nonparametric inference to the projected data and integrate over all projections from a specific set and with respect to suitable probability measures. In contrast to classical methods, which are applicable for real-valued random variables or random vectors of dimensions lower than the sample size, the tests can be applied to random vectors of dimensions larger than the sample size or even to functional and high-dimensional data. In general, resampling procedures such as bootstrap or permutation are suitable to determine critical values. The idea can be extended to the case of incomplete observations. Moreover, we develop an efficient algorithm for implementing the method. Examples are given for testing goodness-of-fit in a one-sample situation in [1] or for testing marginal homogeneity on the basis of a paired sample in [2]. Here, the test statistics in use can be seen as generalizations of the well-known Cramérvon-Mises test statistics in the one-sample and two-samples case. The treatment of other testing problems is possible as well. By using the theory of U-statistics, for instance, asymptotic null distributions of the test statistics are obtained as the sample size tends to infinity. Standard continuity assumptions ensure the asymptotic exactness of the tests under the null hypothesis and that the tests detect any alternative in the limit. Simulation studies demonstrate size and power of the tests in the finite sample case, confirm the theoretical findings, and are used for the comparison with concurring procedures. A possible application of the general approach is inference for stock market returns, also in high data frequencies. In the field of empirical finance, statistical inference of stock market prices usually takes place on the basis of related log-returns as data. In the classical models for stock prices, i.e., the exponential Lévy model, Black-Scholes model, and Merton model, properties such as independence and stationarity of the increments ensure an independent and identically structure of the data. Specific trends during certain periods of the stock price processes can cause complications in this regard. In fact, our approach can compensate those effects by the treatment of the log-returns as random vectors or even as functional data. Y1 - 2022 U6 - https://doi.org/10.11159/icsta22.157 N1 - 4th International Conference on Statistics: Theory and Applications (ICSTA’22), Prague, Czech Republic – July 28- 30 SP - Paper No. 157 PB - Avestia Publishing CY - Orléans, Kanada ER - TY - JOUR A1 - Rübbelke, Dirk A1 - Vögele, Stefan A1 - Grajewski, Matthias A1 - Zobel, Luzy T1 - Cross border adjustment mechanism: Initial data for the assessment of hydrogen-based steel production JF - Data in Brief N2 - Ambitious climate targets affect the competitiveness of industries in the international market. To prevent such industries from moving to other countries in the wake of increased climate protection efforts, cost adjustments may become necessary. Their design requires knowledge of country-specific production costs. Here, we present country-specific cost figures for different production routes of steel, paying particular attention to transportation costs. The data can be used in floor price models aiming to assess the competitiveness of different steel production routes in different countries (Rübbelke, 2022). KW - Energy-intensive industry KW - Steel industry KW - Competitiveness KW - Floor prices KW - Cross border adjustment mechanism Y1 - 2023 U6 - https://doi.org/10.1016/j.dib.2023.108907 SN - 2352-3409 VL - 47 IS - Article 108907 SP - 1 EP - 5 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Ringers, Christa A1 - Bialonski, Stephan A1 - Ege, Mert A1 - Solovev, Anton A1 - Hansen, Jan Niklas A1 - Jeong, Inyoung A1 - Friedrich, Benjamin M. A1 - Jurisch-Yaksi, Nathalie T1 - Novel analytical tools reveal that local synchronization of cilia coincides with tissue-scale metachronal waves in zebrafish multiciliated epithelia JF - eLife N2 - Motile cilia are hair-like cell extensions that beat periodically to generate fluid flow along various epithelial tissues within the body. In dense multiciliated carpets, cilia were shown to exhibit a remarkable coordination of their beat in the form of traveling metachronal waves, a phenomenon which supposedly enhances fluid transport. Yet, how cilia coordinate their regular beat in multiciliated epithelia to move fluids remains insufficiently understood, particularly due to lack of rigorous quantification. We combine experiments, novel analysis tools, and theory to address this knowledge gap. To investigate collective dynamics of cilia, we studied zebrafish multiciliated epithelia in the nose and the brain. We focused mainly on the zebrafish nose, due to its conserved properties with other ciliated tissues and its superior accessibility for non-invasive imaging. We revealed that cilia are synchronized only locally and that the size of local synchronization domains increases with the viscosity of the surrounding medium. Even though synchronization is local only, we observed global patterns of traveling metachronal waves across the zebrafish multiciliated epithelium. Intriguingly, these global wave direction patterns are conserved across individual fish, but different for left and right noses, unveiling a chiral asymmetry of metachronal coordination. To understand the implications of synchronization for fluid pumping, we used a computational model of a regular array of cilia. We found that local metachronal synchronization prevents steric collisions, i.e., cilia colliding with each other, and improves fluid pumping in dense cilia carpets, but hardly affects the direction of fluid flow. In conclusion, we show that local synchronization together with tissue-scale cilia alignment coincide and generate metachronal wave patterns in multiciliated epithelia, which enhance their physiological function of fluid pumping. Y1 - 2023 U6 - https://doi.org/10.7554/eLife.77701 SN - 2050-084X VL - 12 PB - eLife Sciences Publications ER - TY - CHAP A1 - Stollenwerk, Dominik A1 - Franzke, Till A1 - Maurer, Florian A1 - Reinkensmeier, Sebastian A1 - Kim, Franken A1 - Tambornino, Philipp A1 - Haas, Florian A1 - Rieke, Christian A1 - Hermanuz, Andreas A1 - Borchert, Jörg A1 - Ritz, Thomas A1 - Sander, Volker ED - Proff, Heike T1 - Smarte Ladesäulen : Netz- und Marktdienliches öffentliches Laden T2 - Towards the New Normal in Mobility : Technische und betriebswirtschaftliche Aspekte N2 - Stand 01.01.2022 sind in Deutschland 618.460 elektrisch angetriebene KFZ zugelassen. Insgesamt sind derzeit 48.540.878 KFZ zugelassen, was einer Elektromobilitätsquote von ca. 1,2 % entspricht. Derzeit werden Elektromobile über Ladestationen oder Steckdosen mit dem Stromnetz verbunden und üblicherweise mit der vollen Ladekapazität des Anschlusses aufgeladen, bis das Batteriemanagementsystem des Fahrzeugs abhängig vom Ladezustand der Batterie die Ladeleistung reduziert. Y1 - 2023 SN - 978-3-658-39437-0 (Print) SN - 978-3-658-39438-7 (Online) U6 - https://doi.org/10.1007/978-3-658-39438-7_18 SP - 287 EP - 304 PB - Springer Gabler CY - Wiesbaden ER - TY - CHAP A1 - Engelmann, Ulrich M. A1 - Baumann, Martin ED - Herbig, Nicola ED - Poppelreuter, Stefan T1 - Moderationsexpertise für QMBs – Onlinemoderation T2 - Qualitätsmanagement im Gesundheitswesen N2 - Damit Sie auch in den immer häufiger werdenden Onlineveranstaltungen als Moderator gut bestehen, sollten Sie wissen, was bei der Onlinemoderation im Besonderen zu beachten ist. In diesem dritten Teil der Beitragsserie erfahren Sie, warum online anders als offline ist. Die technischen Möglichkeiten werden vorgestellt und auch wie diese zu nutzen sind. Schließlich erhalten Sie Tipps, die Sie beim Sprechen online beachten sollten. Y1 - 2023 SN - 978-3-8249-0714-4 SP - Kapitel 10816 PB - TÜV-Verlag CY - Köln ER - TY - CHAP A1 - Engelmann, Ulrich M. ED - Lindinger, Markus ED - Bartsch, Oliver T1 - Moderationsexpertise – Onlinemoderation T2 - IT-Servicemanagement N2 - Damit Sie auch in den immer häufiger werdenden Onlineveranstaltungen als Moderator gut bestehen, sollten Sie wissen, was bei der Onlinemoderation im Besonderen zu beachten ist. In diesem dritten Teil der Beitragsserie erfahren Sie, warum online anders als offline ist. Die technischen Möglichkeiten werden vorgestellt und auch wie diese zu nutzen sind. Schließlich erhalten Sie Tipps, die Sie beim Sprechen online beachten sollten. Y1 - 2023 SN - 978-3-8249-1154-7 SP - Kapitel 05532 PB - TÜV-Verlag CY - Köln ER - TY - JOUR A1 - Morais, Paulo V. A1 - Suman, Pedro H. A1 - Schöning, Michael Josef A1 - Siqueira Junior, José R. A1 - Orlandi, Marcelo O. T1 - Layer-by-layer film based on Sn₃O₄ nanobelts as sensing units to detect heavy metals using a capacitive field-effect sensor platform JF - Chemosensors N2 - Lead and nickel, as heavy metals, are still used in industrial processes, and are classified as “environmental health hazards” due to their toxicity and polluting potential. The detection of heavy metals can prevent environmental pollution at toxic levels that are critical to human health. In this sense, the electrolyte–insulator–semiconductor (EIS) field-effect sensor is an attractive sensing platform concerning the fabrication of reusable and robust sensors to detect such substances. This study is aimed to fabricate a sensing unit on an EIS device based on Sn₃O₄ nanobelts embedded in a polyelectrolyte matrix of polyvinylpyrrolidone (PVP) and polyacrylic acid (PAA) using the layer-by-layer (LbL) technique. The EIS-Sn₃O₄ sensor exhibited enhanced electrochemical performance for detecting Pb²⁺ and Ni²⁺ ions, revealing a higher affinity for Pb²⁺ ions, with sensitivities of ca. 25.8 mV/decade and 2.4 mV/decade, respectively. Such results indicate that Sn₃O₄ nanobelts can contemplate a feasible proof-of-concept capacitive field-effect sensor for heavy metal detection, envisaging other future studies focusing on environmental monitoring. KW - Sn₃O₄ KW - nanobelts KW - field-effect sensor KW - LbL films KW - heavy metals Y1 - 2023 U6 - https://doi.org/10.3390/chemosensors11080436 SN - 2227-9040 N1 - This article belongs to the Special Issue The Application of Electrochemical Sensors or Biosensors Based on Nanomaterials VL - 11 IS - 8 PB - MDPI CY - Basel ER - TY - THES A1 - Gaigall, Daniel T1 - On selected problems in multivariate analysis N2 - Selected problems in the field of multivariate statistical analysis are treated. Thereby, one focus is on the paired sample case. Among other things, statistical testing problems of marginal homogeneity are under consideration. In detail, properties of Hotelling‘s T² test in a special parametric situation are obtained. Moreover, the nonparametric problem of marginal homogeneity is discussed on the basis of possibly incomplete data. In the bivariate data case, properties of the Hoeffding-Blum-Kiefer-Rosenblatt independence test statistic on the basis of partly not identically distributed data are investigated. Similar testing problems are treated within the scope of the application of a result for the empirical process of the concomitants for partly categorial data. Furthermore, testing changes in the modeled solvency capital requirement of an insurance company by means of a paired sample from an internal risk model is discussed. Beyond the paired sample case, a new asymptotic relative efficiency concept based on the expected volumes of multidimensional confidence regions is introduced. Besides, a new approach for the treatment of the multi-sample goodness-of-fit problem is presented. Finally, a consistent test for the treatment of the goodness-of-fit problem is developed for the background of huge or infinite dimensional data. KW - Paired sample KW - Marginal homogeneity KW - Incomplete data KW - Asymptotic relative efficiency KW - Volumes of confidence regions Y1 - 2023 U6 - https://doi.org/10.15488/14304 N1 - Gottfried Wilhelm Leibniz Universität Hannover ER -