TY - JOUR A1 - Gossmann, Matthias A1 - Thomas, Ulrich A1 - Horváth, András A1 - Dragicevic, Elena A1 - Stoelzle-Feix, Sonja A1 - Jung, Alexander A1 - Raman, Aravind Hariharan A1 - Staat, Manfred A1 - Linder, Peter T1 - A higher-throughput approach to investigate cardiac contractility in vitro under physiological mechanical conditions JF - Journal of Pharmacological and Toxicological Methods Y1 - 2020 U6 - http://dx.doi.org/10.1016/j.vascn.2020.106843 VL - 105 IS - Article 106843 PB - Elsevier CY - New York, NY ER - TY - JOUR A1 - Kopp, Alexander A1 - Schunck, Laura A1 - Gosau, Martin A1 - Smeets, Ralf A1 - Burg, Simon A1 - Fuest, Sandra A1 - Kröger, Nadja A1 - Zinser, Max A1 - Krohn, Sebastian A1 - Behbahani, Mehdi A1 - Köpf, Marius A1 - Lauts, Lisa A1 - Rutkowski, Rico T1 - Influence of the casting concentration on the mechanical and optical properties of Fa/CaCl2-derived silk fibroin membranes JF - International Journal of Molecular Sciences N2 - In this study, we describe the manufacturing and characterization of silk fibroin membranes derived from the silkworm Bombyx mori. To date, the dissolution process used in this study has only been researched to a limited extent, although it entails various potential advantages, such as reduced expenses and the absence of toxic chemicals in comparison to other conventional techniques. Therefore, the aim of this study was to determine the influence of different fibroin concentrations on the process output and resulting membrane properties. Casted membranes were thus characterized with regard to their mechanical, structural and optical assets via tensile testing, SEM, light microscopy and spectrophotometry. Cytotoxicity was evaluated using BrdU, XTT, and LDH assays, followed by live–dead staining. The formic acid (FA) dissolution method was proven to be suitable for the manufacturing of transparent and mechanically stable membranes. The fibroin concentration affects both thickness and transparency of the membranes. The membranes did not exhibit any signs of cytotoxicity. When compared to other current scientific and technical benchmarks, the manufactured membranes displayed promising potential for various biomedical applications. Further research is nevertheless necessary to improve reproducible manufacturing, including a more uniform thickness, less impurity and physiological pH within the membranes. Y1 - 2020 U6 - http://dx.doi.org/10.3390/ijms21186704 SN - 1422-0067 N1 - Special issue: Optimization of Biomaterials for Reconstructive and Regenerative Medicine VL - 21 IS - 18 art. no. 6704 PB - MDPI CY - Basel ER - TY - JOUR A1 - Conzen, Catharina A1 - Albanna, Walid A1 - Weiss, Miriam A1 - Kürten, David A1 - Vilser, Walthard A1 - Kotliar, Konstantin A1 - Zäske, Charlotte A1 - Clusmann, Hans A1 - Schubert, Gerrit Alexander T1 - Vasoconstriction and Impairment of Neurovascular Coupling after Subarachnoid Hemorrhage: a Descriptive Analysis of Retinal Changes JF - Translational Stroke Research N2 - Impaired cerebral autoregulation and neurovascular coupling (NVC) contribute to delayed cerebral ischemia after subarachnoid hemorrhage (SAH). Retinal vessel analysis (RVA) allows non-invasive assessment of vessel dimension and NVC hereby demonstrating a predictive value in the context of various neurovascular diseases. Using RVA as a translational approach, we aimed to assess the retinal vessels in patients with SAH. RVA was performed prospectively in 24 patients with acute SAH (group A: day 5–14), in 11 patients 3 months after ictus (group B: day 90 ± 35), and in 35 age-matched healthy controls (group C). Data was acquired using a Retinal Vessel Analyzer (Imedos Systems UG, Jena) for examination of retinal vessel dimension and NVC using flicker-light excitation. Diameter of retinal vessels—central retinal arteriolar and venular equivalent—was significantly reduced in the acute phase (p < 0.001) with gradual improvement in group B (p < 0.05). Arterial NVC of group A was significantly impaired with diminished dilatation (p < 0.001) and reduced area under the curve (p < 0.01) when compared to group C. Group B showed persistent prolonged latency of arterial dilation (p < 0.05). Venous NVC was significantly delayed after SAH compared to group C (A p < 0.001; B p < 0.05). To our knowledge, this is the first clinical study to document retinal vasoconstriction and impairment of NVC in patients with SAH. Using non-invasive RVA as a translational approach, characteristic patterns of compromise were detected for the arterial and venous compartment of the neurovascular unit in a time-dependent fashion. Recruitment will continue to facilitate a correlation analysis with clinical course and outcome. Y1 - 2018 U6 - http://dx.doi.org/10.1007/s12975-017-0585-8 SN - 1868-601X IS - 9 SP - 284 EP - 293 PB - Springer Nature CY - Cham ER - TY - CHAP A1 - Iomdina, Elena N. A1 - Kiseleva, Anna A. A1 - Kotliar, Konstantin A1 - Luzhnov, Petr V. T1 - Quantification of Choroidal Blood Flow Using the OCT-A System Based on Voxel Scan Processing T2 - 2020 International Conference on Biomedical Innovations and Applications (BIA) Y1 - 2020 SN - 978-1-7281-7073-2 U6 - http://dx.doi.org/10.1109/BIA50171.2020.9244511 SP - 41 EP - 44 ER - TY - JOUR A1 - Neumaier, Felix A1 - Weiss, Miriam A1 - Veldeman, Michael A1 - Kotliar, Konstantin A1 - Wiesmann, Martin A1 - Schulze-Steinen, Henna A1 - Höllig, Anke A1 - Clusmann, Hans A1 - Schubert, Gerrit Alexander A1 - Albanna, Walid T1 - Changes in endogenous daytime melatonin levels after aneurysmal subarachnoid hemorrhage – preliminary findings from an observational cohort study JF - Clinical Neurology and Neurosurgery N2 - Aneurysmal subarachnoid hemorrhage (aSAH) is associated with early and delayed brain injury due to several underlying and interrelated processes, which include inflammation, oxidative stress, endothelial, and neuronal apoptosis. Treatment with melatonin, a cytoprotective neurohormone with anti-inflammatory, anti-oxidant and anti-apoptotic effects, has been shown to attenuate early brain injury (EBI) and to prevent delayed cerebral vasospasm in experimental aSAH models. Less is known about the role of endogenous melatonin for aSAH outcome and how its production is altered by the pathophysiological cascades initiated during EBI. In the present observational study, we analyzed changes in melatonin levels during the first three weeks after aSAH. KW - constructive alignment KW - examination KW - long-term retention KW - multimodal KW - practical learning Y1 - 2021 U6 - http://dx.doi.org/10.1016/j.clineuro.2021.106870 SN - 0303-8467 VL - 208 IS - Article No.: 106870 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Brockhaus, Moritz K. A1 - Behbahani, Mehdi A1 - Muris, Farina A1 - Jansen, Sebastian V. A1 - Schmitz- Rode, Thomas A1 - Steinseifer, Ulrich A1 - Clauser, Johanna C. T1 - In vitro thrombogenicity testing of pulsatile mechanical circulatory support systems: Design and proof-of-concept JF - Artificial Organs N2 - Thrombogenic complications are a main issue in mechanical circulatory support (MCS). There is no validated in vitro method available to quantitatively assess the thrombogenic performance of pulsatile MCS devices under realistic hemodynamic conditions. The aim of this study is to propose a method to evaluate the thrombogenic potential of new designs without the use of complex in-vivo trials. This study presents a novel in vitro method for reproducible thrombogenicity testing of pulsatile MCS systems using low molecular weight heparinized porcine blood. Blood parameters are continuously measured with full blood thromboelastometry (ROTEM; EXTEM, FIBTEM and a custom-made analysis HEPNATEM). Thrombus formation is optically observed after four hours of testing. The results of three experiments are presented each with two parallel loops. The area of thrombus formation inside the MCS device was reproducible. The implantation of a filter inside the loop catches embolizing thrombi without a measurable increase of platelet activation, allowing conclusions of the place of origin of thrombi inside the device. EXTEM and FIBTEM parameters such as clotting velocity (α) and maximum clot firmness (MCF) show a total decrease by around 6% with a characteristic kink after 180 minutes. HEPNATEM α and MCF rise within the first 180 minutes indicate a continuously increasing activation level of coagulation. After 180 minutes, the consumption of clotting factors prevails, resulting in a decrease of α and MCF. With the designed mock loop and the presented protocol we are able to identify thrombogenic hot spots inside a pulsatile pump and characterize their thrombogenic potential. Y1 - 2021 U6 - http://dx.doi.org/10.1111/aor.14046 SN - 1525-1594 VL - 45 IS - 12 SP - 1513 EP - 1521 PB - Wiley CY - Weinheim ER - TY - CHAP A1 - Tran, Ngoc Trinh A1 - Staat, Manfred T1 - FEM shakedown analysis of Kirchhoff-Love plates under uncertainty of strength T2 - Proceedings of UNCECOMP 2021 N2 - A new formulation to calculate the shakedown limit load of Kirchhoff plates under stochastic conditions of strength is developed. Direct structural reliability design by chance con-strained programming is based on the prescribed failure probabilities, which is an effective approach of stochastic programming if it can be formulated as an equivalent deterministic optimization problem. We restrict uncertainty to strength, the loading is still deterministic. A new formulation is derived in case of random strength with lognormal distribution. Upper bound and lower bound shakedown load factors are calculated simultaneously by a dual algorithm. Y1 - 2021 SN - 978-618-85072-6-5 U6 - http://dx.doi.org/10.7712/120221.8041.19047 N1 - Proceedings of UNCECOMP 2021, 4th International Conference on Uncertainty Quantification in Computational Sciences and Engineering, streamed from Athens, Greece, 28–30 June 2021. SP - 323 EP - 338 ER - TY - THES A1 - Jung, Alexander T1 - Electromechanical modelling and simulation of hiPSC-derived cardiac cell cultures Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?https://nbn-resolving.org/urn:nbn:de:hbz:464-20210624-134942-7 SN - 978-3-9821811-1-0 N1 - Dissertation, Universität Duisburg-Essen, 2021 PB - Universität Duisburg-Essen 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 - http://dx.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 - Topçu, Murat A1 - Madabhushi, Gopal S.P. A1 - Staat, Manfred T1 - A generalized shear-lag theory for elastic stress transfer between matrix and fibres having a variable radius JF - International Journal of Solids and Structures N2 - A generalized shear-lag theory for fibres with variable radius is developed to analyse elastic fibre/matrix stress transfer. The theory accounts for the reinforcement of biological composites, such as soft tissue and bone tissue, as well as for the reinforcement of technical composite materials, such as fibre-reinforced polymers (FRP). The original shear-lag theory proposed by Cox in 1952 is generalized for fibres with variable radius and with symmetric and asymmetric ends. Analytical solutions are derived for the distribution of axial and interfacial shear stress in cylindrical and elliptical fibres, as well as conical and paraboloidal fibres with asymmetric ends. Additionally, the distribution of axial and interfacial shear stress for conical and paraboloidal fibres with symmetric ends are numerically predicted. The results are compared with solutions from axisymmetric finite element models. A parameter study is performed, to investigate the suitability of alternative fibre geometries for use in FRP. KW - Natural fibres KW - Polymer-matrix composites KW - Biocomposites KW - Stress concentrations KW - Finite element analysis Y1 - 2022 U6 - http://dx.doi.org/10.1016/j.ijsolstr.2022.111464 SN - 0020-7683 VL - 239–240 IS - Art. No. 111464 PB - Elsevier CY - New York, NY ER - TY - JOUR A1 - Mandekar, Swati A1 - Holland, Abigail A1 - Thielen, Moritz A1 - Behbahani, Mehdi A1 - Melnykowycz, Mark T1 - Advancing towards Ubiquitous EEG, Correlation of In-Ear EEG with Forehead EEG JF - Sensors N2 - Wearable EEG has gained popularity in recent years driven by promising uses outside of clinics and research. The ubiquitous application of continuous EEG requires unobtrusive form-factors that are easily acceptable by the end-users. In this progression, wearable EEG systems have been moving from full scalp to forehead and recently to the ear. The aim of this study is to demonstrate that emerging ear-EEG provides similar impedance and signal properties as established forehead EEG. EEG data using eyes-open and closed alpha paradigm were acquired from ten healthy subjects using generic earpieces fitted with three custom-made electrodes and a forehead electrode (at Fpx) after impedance analysis. Inter-subject variability in in-ear electrode impedance ranged from 20 kΩ to 25 kΩ at 10 Hz. Signal quality was comparable with an SNR of 6 for in-ear and 8 for forehead electrodes. Alpha attenuation was significant during the eyes-open condition in all in-ear electrodes, and it followed the structure of power spectral density plots of forehead electrodes, with the Pearson correlation coefficient of 0.92 between in-ear locations ELE (Left Ear Superior) and ERE (Right Ear Superior) and forehead locations, Fp1 and Fp2, respectively. The results indicate that in-ear EEG is an unobtrusive alternative in terms of impedance, signal properties and information content to established forehead EEG. KW - in-ear EEG KW - correlation KW - forehead EEG KW - impedance spectroscopy KW - biopotential electrodes Y1 - 2022 U6 - http://dx.doi.org/10.3390/s22041568 SN - 1424-8220 VL - 22 IS - 4 SP - 1 EP - 19 PB - MDPI CY - Basel ER - TY - JOUR A1 - Defosse, Jerome A1 - Kleinschmidt, Joris A1 - Schmutz, Axel A1 - Loop, Torsten A1 - Staat, Manfred A1 - Gatzweiler, Karl-Heinz A1 - Wappler, Frank A1 - Schieren, Mark T1 - Dental strain on maxillary incisors during tracheal intubation with double-lumen tubes and different laryngoscopy techniques - a blinded manikin study JF - Journal of Cardiothoracic and Vascular Anesthesia KW - anaesthetic complications KW - dental trauma KW - difficult airway KW - double-lumen tube intubation KW - videolaryngoscopy Y1 - 2022 U6 - http://dx.doi.org/10.1053/j.jvca.2022.02.017 SN - 1053-0770 VL - 36 IS - 8, Part B SP - 3021 EP - 3027 PB - Elsevier CY - New York, NY ER - TY - JOUR A1 - Bhattarai, Aroj A1 - May, Charlotte Anabell A1 - Staat, Manfred A1 - Kowalczyk, Wojciech A1 - Tran, Thanh Ngoc T1 - Layer-specific damage modeling of porcine large intestine under biaxial tension JF - Bioengineering N2 - The mechanical behavior of the large intestine beyond the ultimate stress has never been investigated. Stretching beyond the ultimate stress may drastically impair the tissue microstructure, which consequently weakens its healthy state functions of absorption, temporary storage, and transportation for defecation. Due to closely similar microstructure and function with humans, biaxial tensile experiments on the porcine large intestine have been performed in this study. In this paper, we report hyperelastic characterization of the large intestine based on experiments in 102 specimens. We also report the theoretical analysis of the experimental results, including an exponential damage evolution function. The fracture energies and the threshold stresses are set as damage material parameters for the longitudinal muscular, the circumferential muscular and the submucosal collagenous layers. A biaxial tensile simulation of a linear brick element has been performed to validate the applicability of the estimated material parameters. The model successfully simulates the biomechanical response of the large intestine under physiological and non-physiological loads. KW - biaxial tensile experiment KW - anisotropy KW - hyperelastic KW - constitutive modeling KW - damage Y1 - 2022 U6 - http://dx.doi.org/10.3390/bioengineering9100528 SN - 2306-5354 N1 - Der Artikel gehört zum Sonderheft "Computational Biomechanics" VL - 9 IS - 10, Early Access SP - 1 EP - 17 PB - MDPI CY - Basel ER - TY - JOUR A1 - Colombo, Daniele A1 - Drira, Slah A1 - Frotscher, Ralf A1 - Staat, Manfred T1 - An element-based formulation for ES-FEM and FS-FEM models for implementation in standard solid mechanics finite element codes for 2D and 3D static analysis JF - International Journal for Numerical Methods in Engineering N2 - Edge-based and face-based smoothed finite element methods (ES-FEM and FS-FEM, respectively) are modified versions of the finite element method allowing to achieve more accurate results and to reduce sensitivity to mesh distortion, at least for linear elements. These properties make the two methods very attractive. However, their implementation in a standard finite element code is nontrivial because it requires heavy and extensive modifications to the code architecture. In this article, we present an element-based formulation of ES-FEM and FS-FEM methods allowing to implement the two methods in a standard finite element code with no modifications to its architecture. Moreover, the element-based formulation permits to easily manage any type of element, especially in 3D models where, to the best of the authors' knowledge, only tetrahedral elements are used in FS-FEM applications found in the literature. Shape functions for non-simplex 3D elements are proposed in order to apply FS-FEM to any standard finite element. KW - distorted element KW - ES-FEM KW - FS-FEM KW - non-simplex S-FEM elements KW - S-FEM Y1 - 2022 U6 - http://dx.doi.org/10.1002/nme.7126 SN - 1097-0207 VL - 124 IS - 2 SP - 402 EP - 433 PB - Wiley CY - Chichester ER - TY - JOUR A1 - Kotliar, Konstantin A1 - Ortner, Marion A1 - Conradi, Anna A1 - Hacker, Patricia A1 - Hauser, Christine A1 - Günthner, Roman A1 - Moser, Michaela A1 - Muggenthaler, Claudia A1 - Diehl-Schmid, Janine A1 - Priller, Josef A1 - Schmaderer, Christoph A1 - Grimmer, Timo T1 - Altered retinal cerebral vessel oscillation frequencies in Alzheimer's disease compatible with impaired amyloid clearance JF - Neurobiology of Aging N2 - Retinal vessels are similar to cerebral vessels in their structure and function. Moderately low oscillation frequencies of around 0.1 Hz have been reported as the driving force for paravascular drainage in gray matter in mice and are known as the frequencies of lymphatic vessels in humans. We aimed to elucidate whether retinal vessel oscillations are altered in Alzheimer's disease (AD) at the stage of dementia or mild cognitive impairment (MCI). Seventeen patients with mild-to-moderate dementia due to AD (ADD); 23 patients with MCI due to AD, and 18 cognitively healthy controls (HC) were examined using Dynamic Retinal Vessel Analyzer. Oscillatory temporal changes of retinal vessel diameters were evaluated using mathematical signal analysis. Especially at moderately low frequencies around 0.1 Hz, arterial oscillations in ADD and MCI significantly prevailed over HC oscillations and correlated with disease severity. The pronounced retinal arterial vasomotion at moderately low frequencies in the ADD and MCI groups would be compatible with the view of a compensatory upregulation of paravascular drainage in AD and strengthen the amyloid clearance hypothesis. KW - Alzheimer's disease KW - Retinal vessel analysis KW - Vasomotions KW - Pulsations KW - Mild cognitive impairment Y1 - 2022 U6 - http://dx.doi.org/10.1016/j.neurobiolaging.2022.08.012 SN - 0197-4580 VL - 120 SP - 117 EP - 127 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Bayer, Robin A1 - Temiz Artmann, Aysegül A1 - Digel, Ilya A1 - Falkenstein, Julia A1 - Artmann, Gerhard A1 - Creutz, Till A1 - Hescheler, Jürgen T1 - Mechano-pharmacological testing of L-Type Ca²⁺ channel modulators via human vascular celldrum model JF - Cellular Physiology and Biochemistry N2 - Background/Aims: This study aimed to establish a precise and well-defined working model, assessing pharmaceutical effects on vascular smooth muscle cell monolayer in-vitro. It describes various analysis techniques to determine the most suitable to measure the biomechanical impact of vasoactive agents by using CellDrum technology. Methods: The so-called CellDrum technology was applied to analyse the biomechanical properties of confluent human aorta muscle cells (haSMC) in monolayer. The cell generated tensions deviations in the range of a few N/m² are evaluated by the CellDrum technology. This study focuses on the dilative and contractive effects of L-type Ca²⁺ channel agonists and antagonists, respectively. We analyzed the effects of Bay K8644, nifedipine and verapamil. Three different measurement modes were developed and applied to determine the most appropriate analysis technique for the study purpose. These three operation modes are called, particular time mode" (PTM), "long term mode" (LTM) and "real-time mode" (RTM). Results: It was possible to quantify the biomechanical response of haSMCs to the addition of vasoactive agents using CellDrum technology. Due to the supplementation of 100nM Bay K8644, the tension increased approximately 10.6% from initial tension maximum, whereas, the treatment with nifedipine and verapamil caused a significant decrease in cellular tension: 10nM nifedipine decreased the biomechanical stress around 6,5% and 50nM verapamil by 2,8%, compared to the initial tension maximum. Additionally, all tested measurement modes provide similar results while focusing on different analysis parameters. Conclusion: The CellDrum technology allows highly sensitive biomechanical stress measurements of cultured haSMC monolayers. The mechanical stress responses evoked by the application of vasoactive calcium channel modulators were quantified functionally (N/m²). All tested operation modes resulted in equal findings, whereas each mode features operation-related data analysis. Y1 - 2020 U6 - http://dx.doi.org/10.33594/000000225 SN - 1421-9778 VL - 54 SP - 371 EP - 383 PB - Cell Physiol Biochem Press CY - Düsseldorf ER - TY - JOUR A1 - Akimbekov, Nuraly A1 - Digel, Ilya A1 - Abdieva, Gulzhamal A1 - Ualieva, Perizat A1 - Tastambek, Kuanysh T1 - Lignite biosolubilization and bioconversion by Bacillus sp.: the collation of analytical data JF - Biofuels N2 - The vast metabolic potential of microbes in brown coal (lignite) processing and utilization can greatly contribute to innovative approaches to sustainable production of high-value products from coal. In this study, the multi-faceted and complex coal biosolubilization process by Bacillus sp. RKB 7 isolate from the Kazakhstan coal-mining soil is reported, and the derived products are characterized. Lignite solubilization tests performed for surface and suspension cultures testify to the formation of numerous soluble lignite-derived substances. Almost 24% of crude lignite (5% w/v) was solubilized within 14 days under slightly alkaline conditions (pH 8.2). FTIR analysis revealed various functional groups in the obtained biosolubilization products. Analyses of the lignite-derived humic products by UV-Vis and fluorescence spectrometry as well as elemental analysis yielded compatible results indicating the emerging products had a lower molecular weight and degree of aromaticity. Furthermore, XRD and SEM analyses were used to evaluate the biosolubilization processes from mineralogical and microscopic points of view. The findings not only contribute to a deeper understanding of microbe–mineral interactions in coal environments, but also contribute to knowledge of coal biosolubilization and bioconversion with regard to sustainable production of humic substances. The detailed and comprehensive analyses demonstrate the huge biotechnological potential of Bacillus sp. for agricultural productivity and environmental health. KW - humic acid KW - Bacillus sp KW - lignite KW - Biosolubilization Y1 - 2021 SN - 1759-7277 VL - 12 IS - 3 SP - 247 EP - 258 PB - Taylor & Francis CY - London ER - TY - JOUR A1 - Quittmann, Oliver J. A1 - Abel, Thomas A1 - Albracht, Kirsten A1 - Meskemper, Joshua A1 - Foitschik, Tina A1 - Strüder, Heiko K. T1 - Biomechanics of handcycling propulsion in a 30-min continuous load test at lactate threshold: Kinetics, kinematics, and muscular activity in able-bodied participants JF - European Journal of Applied Physiology N2 - Purpose This study aims to investigate the biomechanics of handcycling during a continuous load trial (CLT) to assess the mechanisms underlying fatigue in upper body exercise. Methods Twelve able-bodied triathletes performed a 30-min CLT at a power output corresponding to lactate threshold in a racing recumbent handcycle mounted on a stationary ergometer. During the CLT, ratings of perceived exertion (RPE), tangential crank kinetics, 3D joint kinematics, and muscular activity of ten muscles of the upper extremity and trunk were examined using motion capturing and surface electromyography. Results During the CLT, spontaneously chosen cadence and RPE increased, whereas crank torque decreased. Rotational work was higher during the pull phase. Peripheral RPE was higher compared to central RPE. Joint range of motion decreased for elbow-flexion and radial-duction. Integrated EMG (iEMG) increased in the forearm flexors, forearm extensors, and M. deltoideus (Pars spinalis). An earlier onset of activation was found for M. deltoideus (Pars clavicularis), M. pectoralis major, M. rectus abdominis, M. biceps brachii, and the forearm flexors. Conclusion Fatigue-related alterations seem to apply analogously in handcycling and cycling. The most distal muscles are responsible for force transmission on the cranks and might thus suffer most from neuromuscular fatigue. The findings indicate that peripheral fatigue (at similar lactate values) is higher in handcycling compared to leg cycling, at least for inexperienced participants. An increase in cadence might delay peripheral fatigue by a reduced vascular occlusion. We assume that the gap between peripheral and central fatigue can be reduced by sport-specific endurance training. Y1 - 2020 U6 - http://dx.doi.org/10.1007/s00421-020-04373-x SN - 1439-6327 IS - 120 SP - 1403 EP - 1415 PB - Springer CY - Heidelberg ER - TY - CHAP A1 - Pohle-Fröhlich, Regina A1 - Dalitz, Christoph A1 - Richter, Charlotte A1 - Hahnen, Tobias A1 - Stäudle, Benjamin A1 - Albracht, Kirsten T1 - Estimation of muscle fascicle orientation in ultrasonic images T2 - VISIGRAPP 2020 - Proceedings of the 15th International Joint Conference on Computer Vision, Imaging and Computer Graphics Theory and Applications, 5 Y1 - 2020 SP - 79 EP - 86 ER - TY - JOUR A1 - Knox, Ronald A1 - Bruggemann, Andrea A1 - Gossmann, Matthias A1 - Thomas, Ulrich A1 - Horváth, András A1 - Dragicevic, Elena A1 - Stoelzle-Feix, Sonja A1 - Fertig, Niels A1 - Jung, Alexander A1 - Raman, Aravind Hariharan A1 - Staat, Manfred A1 - Linder, Peter T1 - Combining physiological relevance and throughput for in vitro cardiac contractility measurement JF - Biophysical Journal N2 - Despite increasing acceptance of human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) in safety pharmacology, controversy remains about the physiological relevance of existing in vitro models for their mechanical testing. We hypothesize that existing signs of immaturity of the cell models result from an improper mechanical environment. We cultured hiPSC-CMs in a 96-well format on hyperelastic silicone membranes imitating their native mechanical environment, resulting in physiological responses to compound stimuli.We validated cell responses on the FLEXcyte 96, with a set of reference compounds covering a broad range of cellular targets, including ion channel modulators, adrenergic receptor modulators and kinase inhibitors. Acute (10 - 30 min) and chronic (up to 7 days) effects were investigated. Furthermore, the measurements were complemented with electromechanical models based on electrophysiological recordings of the used cell types.hiPSC-CMs were cultured on freely-swinging, ultra-thin and hyperelastic silicone membranes. The weight of the cell culture medium deflects the membranes downwards. Rhythmic contraction of the hiPSC-CMs resulted in dynamic deflection changes which were quantified by capacitive distance sensing. The cells were cultured for 7 days prior to compound addition. Acute measurements were conducted 10-30 minutes after compound addition in standard culture medium. For chronic treatment, compound-containing medium was replaced daily for up to 7 days. Electrophysiological properties of the employed cell types were recorded by automated patch-clamp (Patchliner) and the results were integrated into the electromechanical model of the system.Calcium channel agonist S Bay K8644 and beta-adrenergic stimulator isoproterenol induced significant positive inotropic responses without additional external stimulation. Kinase inhibitors displayed cardiotoxic effects on a functional level at low concentrations. The system-integrated analysis detected alterations in beating shape as well as frequency and arrhythmic events and we provide a quantitative measure of these. Y1 - 2020 U6 - http://dx.doi.org/10.1016/j.bpj.2019.11.3104 SN - 0006-3495 N1 - Raman, Arayind Hariharan im Artikel unter dem Namen: Raman, Alexander H. VL - 118 IS - Issue 3, Supplement 1 SP - 570a PB - Elsevier CY - Amsterdam ER -