TY - CHAP A1 - Schmitz, Annika A1 - Apandi, Shah Eiman Amzar Shah A1 - Spillner, Jan A1 - Hima, Flutura A1 - Behbahani, Mehdi ED - Digel, Ilya ED - Staat, Manfred ED - Trzewik, Jürgen ED - Sielemann, Stefanie ED - Erni, Daniel ED - Zylka, Waldemar T1 - Effect of different cannula positions in the pulmonary artery on blood flow and gas exchange using computational fluid dynamics analysis T2 - YRA MedTech Symposium (2024) N2 - Pulmonary arterial cannulation is a common and effective method for percutaneous mechanical circulatory support for concurrent right heart and respiratory failure [1]. However, limited data exists to what effect the positioning of the cannula has on the oxygen perfusion throughout the pulmonary artery (PA). This study aims to evaluate, using computational fluid dynamics (CFD), the effect of different cannula positions in the PA with respect to the oxygenation of the different branching vessels in order for an optimal cannula position to be determined. The four chosen different positions (see Fig. 1) of the cannulas are, in the lower part of the main pulmonary artery (MPA), in the MPA at the junction between the right pulmonary artery (RPA) and the left pulmonary artery (LPA), in the RPA at the first branch of the RPA and in the LPA at the first branch of the LPA. Y1 - 2024 SN - 978-3-940402-65-3 U6 - https://doi.org/10.17185/duepublico/81475 N1 - 4th YRA MedTech Symposium, February 1, 2024. FH Aachen, Campus Jülich SP - 29 EP - 30 PB - Universität Duisburg-Essen CY - Duisburg ER - TY - JOUR A1 - Yoshinobu, Tatsuo A1 - Miyamoto, Ko-ichiro A1 - Wagner, Torsten A1 - Schöning, Michael Josef T1 - Field-effect sensors combined with the scanned light pulse technique: from artificial olfactory images to chemical imaging technologies JF - Chemosensors N2 - The artificial olfactory image was proposed by Lundström et al. in 1991 as a new strategy for an electronic nose system which generated a two-dimensional mapping to be interpreted as a fingerprint of the detected gas species. The potential distribution generated by the catalytic metals integrated into a semiconductor field-effect structure was read as a photocurrent signal generated by scanning light pulses. The impact of the proposed technology spread beyond gas sensing, inspiring the development of various imaging modalities based on the light addressing of field-effect structures to obtain spatial maps of pH distribution, ions, molecules, and impedance, and these modalities have been applied in both biological and non-biological systems. These light-addressing technologies have been further developed to realize the position control of a faradaic current on the electrode surface for localized electrochemical reactions and amperometric measurements, as well as the actuation of liquids in microfluidic devices. KW - visualization KW - light-addressing technologies KW - scanned light pulse technique KW - field-effect structure KW - MOS KW - metal-oxide-semiconductor structure KW - catalytic metal KW - electronic nose KW - gas sensor KW - artificial olfactory image Y1 - 2024 U6 - https://doi.org/10.3390/chemosensors12020020 SN - 2227-9040 N1 - This article belongs to the Special Issue "An Exciting Journey of Chemical Sensors and Biosensors: A Theme Issue in Honor of Professor Ingemar Lundström" Corresponding author: Tatsuo Yoshinobu, Michael J. Schöning VL - 12 IS - 2 PB - MDPI CY - Basel ER - TY - JOUR A1 - Tix, Julian A1 - Moll, Fabian A1 - Krafft, Simone A1 - Betsch, Matthias A1 - Tippkötter, Nils T1 - Hydrogen production from enzymatic pretreated organic waste with thermotoga neapolitana JF - Energies N2 - Biomass from various types of organic waste was tested for possible use in hydrogen production. The composition consisted of lignified samples, green waste, and kitchen scraps such as fruit and vegetable peels and leftover food. For this purpose, the enzymatic pretreatment of organic waste with a combination of five different hydrolytic enzymes (cellulase, amylase, glucoamylase, pectinase and xylase) was investigated to determine its ability to produce hydrogen (H2) with the hydrolyzate produced here. In course, the anaerobic rod-shaped bacterium T. neapolitana was used for H2 production. First, the enzymes were investigated using different substrates in preliminary experiments. Subsequently, hydrolyses were carried out using different types of organic waste. In the hydrolysis carried out here for 48 h, an increase in glucose concentration of 481% was measured for waste loads containing starch, corresponding to a glucose concentration at the end of hydrolysis of 7.5 g·L−1. In the subsequent set fermentation in serum bottles, a H2 yield of 1.26 mmol H2 was obtained in the overhead space when Terrific Broth Medium with glucose and yeast extract (TBGY medium) was used. When hydrolyzed organic waste was used, even a H2 yield of 1.37 mmol could be achieved in the overhead space. In addition, a dedicated reactor system for the anaerobic fermentation of T. neapolitana to produce H2 was developed. The bioreactor developed here can ferment anaerobically with a very low loss of produced gas. Here, after 24 h, a hydrogen concentration of 83% could be measured in the overhead space. KW - Biological hydrogen KW - Organic waste KW - Dark fermentation KW - Hydrolysis KW - Pretreatment Y1 - 2024 U6 - https://doi.org/10.3390/en17122938 SN - 1996-1073 N1 - Corresponding author: Nils Tippkötter VL - 17 IS - 12 PB - MDPI CY - Basel ER - TY - JOUR A1 - Thoma, Andreas A1 - Gardi, Alessandro A1 - Fisher, Alex A1 - Braun, Carsten T1 - Improving local path planning for UAV flight in challenging environments by refining cost function weights JF - CEAS Aeronautical Journal N2 - Unmanned Aerial Vehicles (UAV) constantly gain in versatility. However, more reliable path planning algorithms are required until full autonomous UAV operation is possible. This work investigates the algorithm 3DVFH* and analyses its dependency on its cost function weights in 2400 environments. The analysis shows that the 3DVFH* can find a suitable path in every environment. However, a particular type of environment requires a specific choice of cost function weights. For minimal failure, probability interdependencies between the weights of the cost function have to be considered. This dependency reduces the number of control parameters and simplifies the usage of the 3DVFH*. Weights for costs associated with vertical evasion (pitch cost) and vicinity to obstacles (obstacle cost) have the highest influence on the failure probability of the local path planner. Environments with mainly very tall buildings (like large American city centres) require a preference for horizontal avoidance manoeuvres (achieved with high pitch cost weights). In contrast, environments with medium-to-low buildings (like European city centres) benefit from vertical avoidance manoeuvres (achieved with low pitch cost weights). The cost of the vicinity to obstacles also plays an essential role and must be chosen adequately for the environment. Choosing these two weights ideal is sufficient to reduce the failure probability below 10%. KW - Bio-inspired systems KW - Path planning KW - Obstacle avoidance KW - Unmanned aerial vehicles Y1 - 2024 U6 - https://doi.org/10.1007/s13272-024-00741-x SN - 1869-5590 (eISSN) SN - 1869-5582 N1 - Corresponding author: Andreas Thoma PB - Springer CY - Wien ER - TY - JOUR A1 - Bertz, Morten A1 - Schöning, Michael Josef A1 - Molinnus, Denise A1 - Homma, Takayuki T1 - Influence of temperature, light, and H₂O₂ concentration on microbial spore inactivation: in-situ Raman spectroscopy combined with optical trapping JF - Physica status solidi (a) applications and materials science N2 - To gain insight on chemical sterilization processes, the influence of temperature (up to 70 °C), intense green light, and hydrogen peroxide (H₂O₂) concentration (up to 30% in aqueous solution) on microbial spore inactivation is evaluated by in-situ Raman spectroscopy with an optical trap. Bacillus atrophaeus is utilized as a model organism. Individual spores are isolated and their chemical makeup is monitored under dynamically changing conditions (temperature, light, and H₂O₂ concentration) to mimic industrially relevant process parameters for sterilization in the field of aseptic food processing. While isolated spores in water are highly stable, even at elevated temperatures of 70 °C, exposure to H₂O₂ leads to a loss of spore integrity characterized by the release of the key spore biomarker dipicolinic acid (DPA) in a concentration-dependent manner, which indicates damage to the inner membrane of the spore. Intensive light or heat, both of which accelerate the decomposition of H₂O₂ into reactive oxygen species (ROS), drastically shorten the spore lifetime, suggesting the formation of ROS as a rate-limiting step during sterilization. It is concluded that Raman spectroscopy can deliver mechanistic insight into the mode of action of H₂O₂-based sterilization and reveal the individual contributions of different sterilization methods acting in tandem. KW - hydrogen peroxide KW - optical spore trapping KW - Raman spectroscopy KW - sterilization conditions KW - temperature Y1 - 2024 U6 - https://doi.org/10.1002/pssa.202300866 SN - 1862-6319 (Online) SN - 1862-6300 (Print) N1 - Corresponding author: Michael J. Schöning IS - Early View PB - Wiley-VCH CY - Berlin ER - TY - BOOK A1 - Drumm, Christian A1 - Scheuermann, Bernd A1 - Weidner, Stefan T1 - Introduction to SAP S/4HANA® : The official companion book based on model company Global Bike–for learning, teaching, and training N2 - This easy-to-understand introduction to SAP S/4HANA guides you through the central processes in sales, purchasing and procurement, finance, production, and warehouse management using the model company Global Bike. Familiarize yourself with the basics of business administration, the relevant organizational data, master data, and transactional data, as well as a selection of core business processes in SAP. Using practical examples and tutorials, you will soon become an SAP S/4HANA professional! Tutorials and exercises for beginners, advanced users, and experts make it easy for you to practice your new knowledge. The prerequisite for this book is access to an SAP S/4HANA client with Global Bike version 4.1. - Business fundamentals and processes in the SAP system - Sales, purchasing and procurement, production, finance, and warehouse management - Tutorials at different qualification levels, exercises, and recap of case studies - Includes extensive download material for students, lecturers, and professors Y1 - 2024 SN - 9783960122685 PB - Espresso Tutorials CY - Gleichen ER - TY - JOUR A1 - Engelmann, Ulrich M. A1 - Simsek, Beril A1 - Shalaby, Ahmed A1 - Krause, Hans-Joachim T1 - Key contributors to signal generation in frequency mixing magnetic detection (FMMD): an in silico study JF - Sensors N2 - Frequency mixing magnetic detection (FMMD) is a sensitive and selective technique to detect magnetic nanoparticles (MNPs) serving as probes for binding biological targets. Its principle relies on the nonlinear magnetic relaxation dynamics of a particle ensemble interacting with a dual frequency external magnetic field. In order to increase its sensitivity, lower its limit of detection and overall improve its applicability in biosensing, matching combinations of external field parameters and internal particle properties are being sought to advance FMMD. In this study, we systematically probe the aforementioned interaction with coupled Néel–Brownian dynamic relaxation simulations to examine how key MNP properties as well as applied field parameters affect the frequency mixing signal generation. It is found that the core size of MNPs dominates their nonlinear magnetic response, with the strongest contributions from the largest particles. The drive field amplitude dominates the shape of the field-dependent response, whereas effective anisotropy and hydrodynamic size of the particles only weakly influence the signal generation in FMMD. For tailoring the MNP properties and parameters of the setup towards optimal FMMD signal generation, our findings suggest choosing large particles of core sizes dc > 25 nm nm with narrow size distributions (σ < 0.1) to minimize the required drive field amplitude. This allows potential improvements of FMMD as a stand-alone application, as well as advances in magnetic particle imaging, hyperthermia and magnetic immunoassays. KW - key performance indicators KW - magnetic biosensing KW - coupled Néel–Brownian relaxation dynamics KW - frequency mixing magnetic detection KW - magnetic relaxation KW - micromagnetic simulation KW - magnetic nanoparticles Y1 - 2024 U6 - https://doi.org/10.3390/s24061945 SN - 1424-8220 N1 - This article belongs to the Special Issue "Advances in Magnetic Sensors and Their Applications" VL - 24 IS - 6 PB - MDPI CY - Basel ER - TY - JOUR A1 - Adels, Klaudia A1 - Monakhova, Yulia T1 - Low-field NMR spectroscopic study of e-cigarettes: Is determination of only nicotine and organic carrier solvents possible? JF - Microchemical Journal N2 - Electronic cigarettes (e-cigarettes) have become popular worldwide with the market growing exponentially in some countries. The absence of product standards and safety regulations requires urgent development of analytical methodologies for the holistic control of the growing diversity of such products. An approach based on low-field nuclear magnetic resonance (LF-NMR) at 80 MHz is presented for the simultaneous determination of key parameters: carrier solvents (vegetable glycerine (VG), propylene glycol (PG) and water), total nicotine as well as free-base nicotine fraction. Moreover, qualitative and quantitative determination of fourteen weak organic acids deliberately added to enhance sensory characteristics of e-cigarettes was possible. In most cases these parameters can be rapidly and conveniently determined without using any sample manipulation such as dilution, extraction or derivatization steps. The method was applied for 37 authentic e-cigarettes samples. In particular, eight different organic acids with the content up to 56 mg/mL were detected. Due to its simplicity, the method can be used in routine regulatory control as well as to study release behaviour of nicotine and other e-cigarettes constituents in different products. KW - Electronic cigarettes KW - Low field NMR KW - Carrier solvents KW - Free-base nicotine KW - Weak organic acids Y1 - 2024 U6 - https://doi.org/10.1016/j.microc.2024.110859 SN - 1095-9149 N1 - Corresponding author: Yulia Monakhova VL - 203 PB - Elsevier CY - Amsterdam ER - TY - CHAP A1 - Becker, Tim A1 - Bragard, Michael T1 - Low-Voltage DC Training Lab for Electric Drives - Optimizing the Balancing Act Between High Student Throughput and Individual Learning Speed T2 - 2024 IEEE Global Engineering Education Conference (EDUCON) N2 - After a brief introduction of conventional laboratory structures, this work focuses on an innovative and universal approach for a setup of a training laboratory for electric machines and drive systems. The novel approach employs a central 48 V DC bus, which forms the backbone of the structure. Several sets of DC machine, asynchronous machine and synchronous machine are connected to this bus. The advantages of the novel system structure are manifold, both from a didactic and a technical point of view: Student groups can work on their own performance level in a highly parallelized and at the same time individualized way. Additional training setups (similar or different) can easily be added. Only the total power dissipation has to be provided, i.e. the DC bus balances the power flow between the student groups. Comparative results of course evaluations of several cohorts of students are shown. KW - Synchronous machines KW - Power dissipation KW - Throughput KW - Low voltage KW - DC machines KW - Manifolds KW - Training Y1 - 2024 U6 - https://doi.org/10.1109/EDUCON60312.2024.10578902 SN - 2165-9559 SN - 2165-9567 (eISSN) N1 - 2024 IEEE Global Engineering Education Conference (EDUCON), 08-11 May 2024, Kos Island, Greece PB - IEEE CY - New York, NY ER - TY - CHAP A1 - Simsek, Beril A1 - Krause, Hans-Joachim A1 - Engelmann, Ulrich M. ED - Digel, Ilya ED - Staat, Manfred ED - Trzewik, Jürgen ED - Sielemann, Stefanie ED - Erni, Daniel ED - Zylka, Waldemar T1 - Magnetic biosensing with magnetic nanoparticles: Simulative approach to predict signal intensity in frequency mixing magnetic detection T2 - YRA MedTech Symposium (2024) N2 - Magnetic nanoparticles (MNP) are investigated with great interest for biomedical applications in diagnostics (e.g. imaging: magnetic particle imaging (MPI)), therapeutics (e.g. hyperthermia: magnetic fluid hyperthermia (MFH)) and multi-purpose biosensing (e.g. magnetic immunoassays (MIA)). What all of these applications have in common is that they are based on the unique magnetic relaxation mechanisms of MNP in an alternating magnetic field (AMF). While MFH and MPI are currently the most prominent examples of biomedical applications, here we present results on the relatively new biosensing application of frequency mixing magnetic detection (FMMD) from a simulation perspective. In general, we ask how the key parameters of MNP (core size and magnetic anisotropy) affect the FMMD signal: by varying the core size, we investigate the effect of the magnetic volume per MNP; and by changing the effective magnetic anisotropy, we study the MNPs’ flexibility to leave its preferred magnetization direction. From this, we predict the most effective combination of MNP core size and magnetic anisotropy for maximum signal generation. Y1 - 2024 SN - 978-3-940402-65-3 U6 - https://doi.org/10.17185/duepublico/81475 N1 - 4th YRA MedTech Symposium, February 1, 2024. FH Aachen, Campus Jülich SP - 27 EP - 28 PB - Universität Duisburg-Essen CY - Duisburg ER - TY - JOUR A1 - Schoenrock, Britt A1 - Muckelt, Paul E. A1 - Hastermann, Maria A1 - Albracht, Kirsten A1 - MacGregor, Robert A1 - Martin, David A1 - Gunga, Hans-Christian A1 - Salanova, Michele A1 - Stokes, Maria J. A1 - Warner, Martin B. A1 - Blottner, Dieter T1 - Muscle stiffness indicating mission crew health in space JF - Scientific Reports N2 - Muscle function is compromised by gravitational unloading in space affecting overall musculoskeletal health. Astronauts perform daily exercise programmes to mitigate these effects but knowing which muscles to target would optimise effectiveness. Accurate inflight assessment to inform exercise programmes is critical due to lack of technologies suitable for spaceflight. Changes in mechanical properties indicate muscle health status and can be measured rapidly and non-invasively using novel technology. A hand-held MyotonPRO device enabled monitoring of muscle health for the first time in spaceflight (> 180 days). Greater/maintained stiffness indicated countermeasures were effective. Tissue stiffness was preserved in the majority of muscles (neck, shoulder, back, thigh) but Tibialis Anterior (foot lever muscle) stiffness decreased inflight vs. preflight (p < 0.0001; mean difference 149 N/m) in all 12 crewmembers. The calf muscles showed opposing effects, Gastrocnemius increasing in stiffness Soleus decreasing. Selective stiffness decrements indicate lack of preservation despite daily inflight countermeasures. This calls for more targeted exercises for lower leg muscles with vital roles as ankle joint stabilizers and in gait. Muscle stiffness is a digital biomarker for risk monitoring during future planetary explorations (Moon, Mars), for healthcare management in challenging environments or clinical disorders in people on Earth, to enable effective tailored exercise programmes. KW - Ageing KW - Anatomy KW - Muscle KW - Musculoskeletal system KW - Physiology Y1 - 2024 U6 - https://doi.org/10.1038/s41598-024-54759-6 SN - 2045-2322 N1 - Corresponding author: Dieter Blottner VL - 14 IS - Article number: 4196 PB - Springer Nature CY - London ER - TY - JOUR A1 - Oehlenschläger, Katharina A1 - Volkmar, Marianne A1 - Stiefelmaier, Judith A1 - Langsdorf, Alexander A1 - Holtmann, Dirk A1 - Tippkötter, Nils A1 - Ulber, Roland T1 - New insights into the influence of pre-culture on robust solvent production of C. acetobutylicum JF - Applied Microbiology and Biotechnology N2 - Clostridia are known for their solvent production, especially the production of butanol. Concerning the projected depletion of fossil fuels, this is of great interest. The cultivation of clostridia is known to be challenging, and it is difficult to achieve reproducible results and robust processes. However, existing publications usually concentrate on the cultivation conditions of the main culture. In this paper, the influence of cryo-conservation and pre-culture on growth and solvent production in the resulting main cultivation are examined. A protocol was developed that leads to reproducible cultivations of Clostridium acetobutylicum. Detailed investigation of the cell conservation in cryo-cultures ensured reliable cell growth in the pre-culture. Moreover, a reason for the acid crash in the main culture was found, based on the cultivation conditions of the pre-culture. The critical parameter to avoid the acid crash and accomplish the shift to the solventogenesis of clostridia is the metabolic phase in which the cells of the pre-culture were at the time of inoculation of the main culture; this depends on the cultivation time of the pre-culture. Using cells from the exponential growth phase to inoculate the main culture leads to an acid crash. To achieve the solventogenic phase with butanol production, the inoculum should consist of older cells which are in the stationary growth phase. Considering these parameters, which affect the entire cultivation process, reproducible results and reliable solvent production are ensured. KW - Pre-culture KW - Metabolic shift KW - Acid crash KW - C. acetobutylicum KW - ABE KW - Butanol Y1 - 2024 U6 - https://doi.org/10.1007/s00253-023-12981-8 SN - 1432-0614 VL - 108 PB - Springer CY - Berlin, Heidelberg ER - TY - JOUR A1 - Haeger, Gerrit A1 - Jolmes, Tristan A1 - Oyen, Sven A1 - Jaeger, Karl-Erich A1 - Bongaerts, Johannes A1 - Schörken, Ulrich A1 - Siegert, Petra T1 - Novel recombinant aminoacylase from Paraburkholderia monticola capable of N-acyl-amino acid synthesis JF - Applied Microbiology and Biotechnology N2 - N-Acyl-amino acids can act as mild biobased surfactants, which are used, e.g., in baby shampoos. However, their chemical synthesis needs acyl chlorides and does not meet sustainability criteria. Thus, the identification of biocatalysts to develop greener synthesis routes is desirable. We describe a novel aminoacylase from Paraburkholderia monticola DSM 100849 (PmAcy) which was identified, cloned, and evaluated for its N-acyl-amino acid synthesis potential. Soluble protein was obtained by expression in lactose autoinduction medium and co-expression of molecular chaperones GroEL/S. Strep-tag affinity purification enriched the enzyme 16-fold and yielded 15 mg pure enzyme from 100 mL of culture. Biochemical characterization revealed that PmAcy possesses beneficial traits for industrial application like high temperature and pH-stability. A heat activation of PmAcy was observed upon incubation at temperatures up to 80 °C. Hydrolytic activity of PmAcy was detected with several N-acyl-amino acids as substrates and exhibited the highest conversion rate of 773 U/mg with N-lauroyl-L-alanine at 75 °C. The enzyme preferred long-chain acyl-amino-acids and displayed hardly any activity with acetyl-amino acids. PmAcy was also capable of N-acyl-amino acid synthesis with good conversion rates. The best synthesis results were obtained with the cationic L-amino acids L-arginine and L-lysine as well as with L-leucine and L-phenylalanine. Exemplarily, L-phenylalanine was acylated with fatty acids of chain lengths from C8 to C18 with conversion rates of up to 75%. N-lauroyl-L-phenylalanine was purified by precipitation, and the structure of the reaction product was verified by LC–MS and NMR. KW - Chaperone KW - Biocatalysis KW - Aminoacylase KW - Acylation KW - Acyl-amino acids KW - Biosurfactants Y1 - 2024 U6 - https://doi.org/10.1007/s00253-023-12868-8 SN - 1432-0614 N1 - Corresponding author: Petra Siegert IS - 108 PB - Springer CY - Berlin ER - TY - JOUR A1 - Pieronek, Lukas A1 - Kleefeld, Andreas T1 - On trajectories of complex-valued interior transmission eigenvalues JF - Inverse problems and imaging : IPI N2 - This paper investigates the interior transmission problem for homogeneous media via eigenvalue trajectories parameterized by the magnitude of the refractive index. In the case that the scatterer is the unit disk, we prove that there is a one-to-one correspondence between complex-valued interior transmission eigenvalue trajectories and Dirichlet eigenvalues of the Laplacian which turn out to be exactly the trajectorial limit points as the refractive index tends to infinity. For general simply-connected scatterers in two or three dimensions, a corresponding relation is still open, but further theoretical results and numerical studies indicate a similar connection. KW - Interior transmission problem KW - Eigenvalue trajectories KW - Complex-valued eigenvalues Y1 - 2024 U6 - https://doi.org/10.3934/ipi.2023041 SN - 1930-8337 (Print) SN - 1930-8345 (Online) VL - 18 IS - 2 SP - 480 EP - 516 PB - AIMS CY - Springfield, Mo ER - TY - JOUR A1 - Hoffstadt, Kevin A1 - Nikolausz, Marcell A1 - Krafft, Simone A1 - Bonatelli, Maria A1 - Kumar, Vivekanantha A1 - Harms, Hauke A1 - Kuperjans, Isabel T1 - Optimization of the ex situ biomethanation of hydrogen and carbon dioxide in a novel meandering plug flow reactor: start-up phase and flexible operation JF - Bioengineering KW - methanation KW - plug flow reactor KW - bubble column KW - biomethane KW - P2G Y1 - 2024 U6 - https://doi.org/10.3390/bioengineering11020165 SN - 2306-5354 VL - 11 IS - 2 PB - MDPI CY - Basel ER - TY - INPR A1 - Grieger, Niklas A1 - Mehrkanoon, Siamak A1 - Bialonski, Stephan T1 - Preprint: Data-efficient sleep staging with synthetic time series pretraining T2 - arXiv N2 - Analyzing electroencephalographic (EEG) time series can be challenging, especially with deep neural networks, due to the large variability among human subjects and often small datasets. To address these challenges, various strategies, such as self-supervised learning, have been suggested, but they typically rely on extensive empirical datasets. Inspired by recent advances in computer vision, we propose a pretraining task termed "frequency pretraining" to pretrain a neural network for sleep staging by predicting the frequency content of randomly generated synthetic time series. Our experiments demonstrate that our method surpasses fully supervised learning in scenarios with limited data and few subjects, and matches its performance in regimes with many subjects. Furthermore, our results underline the relevance of frequency information for sleep stage scoring, while also demonstrating that deep neural networks utilize information beyond frequencies to enhance sleep staging performance, which is consistent with previous research. We anticipate that our approach will be advantageous across a broad spectrum of applications where EEG data is limited or derived from a small number of subjects, including the domain of brain-computer interfaces. Y1 - 2024 ER - TY - JOUR A1 - Turdumamatov, Samat A1 - Belda, Aljoscha A1 - Heuermann, Holger T1 - Shaping a decoupled atmospheric pressure microwave plasma with antenna structures, Maxwell’s equations, and boundary conditions JF - IEEE Transactions on Plasma Science N2 - This article addresses the need for an innovative technique in plasma shaping, utilizing antenna structures, Maxwell’s laws, and boundary conditions within a shielded environment. The motivation lies in exploring a novel approach to efficiently generate high-energy density plasma with potential applications across various fields. Implemented in an E01 circular cavity resonator, the proposed method involves the use of an impedance and field matching device with a coaxial connector and a specially optimized monopole antenna. This setup feeds a low-loss cavity resonator, resulting in a high-energy density air plasma with a surface temperature exceeding 3500 o C, achieved with a minimal power input of 80 W. The argon plasma, resembling the shape of a simple monopole antenna with modeled complex dielectric values, offers a more energy-efficient alternative compared to traditional, power-intensive plasma shaping methods. Simulations using a commercial electromagnetic (EM) solver validate the design’s effectiveness, while experimental validation underscores the method’s feasibility and practical implementation. Analyzing various parameters in an argon atmosphere, including hot S -parameters and plasma beam images, the results demonstrate the successful application of this technique, suggesting its potential in coating, furnace technology, fusion, and spectroscopy applications. KW - 3-D printing KW - Furnace KW - Fusion KW - Hot S-parameter KW - Mode converter Y1 - 2024 U6 - https://doi.org/10.1109/TPS.2024.3383589 SN - 0093-3813 (Print) SN - 1939-9375 (Online) IS - Early Access SP - 1 EP - 9 PB - IEEE ER - TY - JOUR A1 - Bornheim, Tobias A1 - Grieger, Niklas A1 - Blaneck, Patrick Gustav A1 - Bialonski, Stephan T1 - Speaker Attribution in German Parliamentary Debates with QLoRA-adapted Large Language Models JF - Journal for language technology and computational linguistics : JLCL N2 - The growing body of political texts opens up new opportunities for rich insights into political dynamics and ideologies but also increases the workload for manual analysis. Automated speaker attribution, which detects who said what to whom in a speech event and is closely related to semantic role labeling, is an important processing step for computational text analysis. We study the potential of the large language model family Llama 2 to automate speaker attribution in German parliamentary debates from 2017-2021. We fine-tune Llama 2 with QLoRA, an efficient training strategy, and observe our approach to achieve competitive performance in the GermEval 2023 Shared Task On Speaker Attribution in German News Articles and Parliamentary Debates. Our results shed light on the capabilities of large language models in automating speaker attribution, revealing a promising avenue for computational analysis of political discourse and the development of semantic role labeling systems. KW - large language models KW - German KW - speaker attribution KW - semantic role labeling Y1 - 2024 U6 - https://doi.org/10.21248/jlcl.37.2024.244 SN - 2190-6858 VL - 37 IS - 1 PB - Gesellschaft für Sprachtechnologie und Computerlinguistik CY - Regensburg ER - TY - JOUR A1 - Chwallek, Constanze A1 - Nawrath, Lara A1 - Krastina, Anzelika A1 - Bruksle, Ieva T1 - Supportive research on sustainable entrepreneurship and business practices JF - SECA Sustainable Entrepreneurship for Climate Action Y1 - 2024 SN - 978-952-316-514-4 (pdf) SN - 2954-1654 (on-line publication) IS - 3 PB - Lapland University of Applied Sciences Ltd CY - Rovaniemi ER - TY - JOUR A1 - Hafidi, Youssef A1 - El Hatka, Hicham A1 - Schmitz, Dominik A1 - Krauss, Manuel A1 - Pettrak, Jürgen A1 - Biel, Markus A1 - Ittobane, Najim T1 - Sustainable soil additives for water and micronutrient supply: swelling and chelating properties of polyaspartic acid hydrogels utilizing newly developed crosslinkers JF - Gels N2 - Drought and water shortage are serious problems in many arid and semi-arid regions. This problem is getting worse and even continues in temperate climatic regions due to climate change. To address this problem, the use of biodegradable hydrogels is increasingly important for the application as water-retaining additives in soil. Furthermore, efficient (micro-)nutrient supply can be provided by the use of tailored hydrogels. Biodegradable polyaspartic acid (PASP) hydrogels with different available (1,6-hexamethylene diamine (HMD) and L-lysine (LYS)) and newly developed crosslinkers based on diesters of glycine (GLY) and (di-)ethylene glycol (DEG and EG, respectively) were synthesized and characterized using Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM) and regarding their swelling properties (kinetic, absorbency under load (AUL)) as well as biodegradability of PASP hydrogel. Copper (II) and zinc (II), respectively, were loaded as micronutrients in two different approaches: in situ with crosslinking and subsequent loading of prepared hydrogels. The results showed successful syntheses of di-glycine-ester-based crosslinkers. Hydrogels with good water-absorbing properties were formed. Moreover, the developed crosslinking agents in combination with the specific reaction conditions resulted in higher water absorbency with increased crosslinker content used in synthesis (10% vs. 20%). The prepared hydrogels are candidates for water-storing soil additives due to the biodegradability of PASP, which is shown in an exemple. The incorporation of Cu(II) and Zn(II) ions can provide these micronutrients for plant growth. KW - micronutrients KW - swelling properties KW - biodegradable polymers KW - hydrogels KW - superabsorbent polymers KW - glycine KW - polyaspartic acid Y1 - 2024 U6 - https://doi.org/10.3390/gels10030170 SN - 2310-2861 VL - 10 IS - 3 SP - Artikel 170 PB - MDPI CY - Basel ER -