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  - 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  - CHAP
A1  - Maurer, Florian
T1  - Framework to provide a simulative comparison of different energy market designs
T2  - Energy Informatics
N2  - Useful market simulations are key to the evaluation of diferent market designs existing of multiple market mechanisms or rules. Yet a simulation framework which has a comparison of diferent market mechanisms in mind was not found. The need to create an objective view on different sets of market rules while investigating meaningful agent strategies concludes that such a simulation framework is needed to advance the research on this subject. An overview of diferent existing market simulation models is given which also shows the research gap and the missing capabilities of those systems. Finally, a methodology is outlined how a novel market simulation which can answer the research questions can be developed.
Y1  - 2022
U6  - https://doi.org/10.1186/s42162-022-00215-6
SN  - 2520-8942
N1  - 11th DACH+ Conference on Energy Informatics, 15-16 September 2022, Freiburg, Germany
VL  - 5
IS  - 2, Article number: 12
SP  - 18
EP  - 20
PB  - Springer Nature
ER  - 
TY  - JOUR
A1  - Herssens, Nolan
A1  - Cowburn, James
A1  - Albracht, Kirsten
A1  - Braunstein, Bjoern
A1  - Cazzola, Dario
A1  - Colyer, Steffi
A1  - Minetti, Alberto E.
A1  - Pavei, Gaspare
A1  - Rittweger, Jörn
A1  - Weber, Tobias
A1  - Green, David A.
ED  - Cattaneo, Luigi
T1  - Movement in low gravity environments (MoLo) programme – the MoLo-L.O.O.P. study protocol
JF  - PLOS ONE / Public Library of Science
N2  - Exposure to prolonged periods in microgravity is associated with deconditioning of the musculoskeletal system due to chronic changes in mechanical stimulation. Given astronauts will operate on the Lunar surface for extended periods of time, it is critical to quantify both external (e.g., ground reaction forces) and internal (e.g., joint reaction forces) loads of relevant movements performed during Lunar missions. Such knowledge is key to predict musculoskeletal deconditioning and determine appropriate exercise countermeasures associated with extended exposure to hypogravity.
Y1  - 2022
U6  - https://doi.org/10.1371/journal.pone.0278051
SN  - 1932-6203
VL  - 17
IS  - 11
PB  - Plos
CY  - San Francisco
ER  - 
TY  - JOUR
A1  - Uysal, Karya
A1  - Firat, Ipek Serat
A1  - Creutz, Till
A1  - Aydin, Inci Cansu
A1  - Artmann, Gerhard
A1  - Teusch, Nicole
A1  - Temiz Artmann, Aysegül
T1  - A novel in vitro wound healing assay using free-standing, ultra-thin PDMS membranes
JF  - membranes
N2  - Advances in polymer science have significantly increased polymer applications in life sciences. We report the use of free-standing, ultra-thin polydimethylsiloxane (PDMS) membranes, called CellDrum, as cell culture substrates for an in vitro wound model. Dermal fibroblast monolayers from 28- and 88-year-old donors were cultured on CellDrums. By using stainless steel balls, circular cell-free areas were created in the cell layer (wounding). Sinusoidal strain of 1 Hz, 5% strain, was applied to membranes for 30 min in 4 sessions. The gap circumference and closure rate of un-stretched samples (controls) and stretched samples were monitored over 4 days to investigate the effects of donor age and mechanical strain on wound closure. A significant decrease in gap circumference and an increase in gap closure rate were observed in trained samples from younger donors and control samples from older donors. In contrast, a significant decrease in gap closure rate and an increase in wound circumference were observed in the trained samples from older donors. Through these results, we propose the model of a cell monolayer on stretchable CellDrums as a practical tool for wound healing research. The combination of biomechanical cell loading in conjunction with analyses such as gene/protein expression seems promising beyond the scope published here.
Y1  - 2022
U6  - https://doi.org/10.3390/membranes13010022
N1  - This article belongs to the Special Issue "Latest Scientific Discoveries in Polymer Membranes"
VL  - 2023
IS  - 13(1)
PB  - MDPI
CY  - Basel
ER  - 
TY  - JOUR
A1  - 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  - JOUR
A1  - Stäudle, Benjamin
A1  - Seynnes, Olivier
A1  - Laps, Guido
A1  - Brüggemann, Gert-Peter
A1  - Albracht, Kirsten
T1  - Altered gastrocnemius contractile behavior in former achilles tendon rupture patients during walking
JF  - Frontiers in Physiology
N2  - Achilles tendon rupture (ATR) remains associated with functional limitations years after injury. Architectural remodeling of the gastrocnemius medialis (GM) muscle is typically observed in the affected leg and may compensate force deficits caused by a longer tendon. Yet patients seem to retain functional limitations during—low-force—walking gait. To explore the potential limits imposed by the remodeled GM muscle-tendon unit (MTU) on walking gait, we examined the contractile behavior of muscle fascicles during the stance phase. In a cross-sectional design, we studied nine former patients (males; age: 45 ± 9 years; height: 180 ± 7 cm; weight: 83 ± 6 kg) with a history of complete unilateral ATR, approximately 4 years post-surgery. Using ultrasonography, GM tendon morphology, muscle architecture at rest, and fascicular behavior were assessed during walking at 1.5 m⋅s–1 on a treadmill. Walking patterns were recorded with a motion capture system. The unaffected leg served as control. Lower limbs kinematics were largely similar between legs during walking. Typical features of ATR-related MTU remodeling were observed during the stance sub-phases corresponding to series elastic element (SEE) lengthening (energy storage) and SEE shortening (energy release), with shorter GM fascicles (36 and 36%, respectively) and greater pennation angles (8° and 12°, respectively). However, relative to the optimal fascicle length for force production, fascicles operated at comparable length in both legs. Similarly, when expressed relative to optimal fascicle length, fascicle contraction velocity was not different between sides, except at the time-point of peak series elastic element (SEE) length, where it was 39 ± 49% lower in the affected leg. Concomitantly, fascicles rotation during contraction was greater in the affected leg during the whole stance-phase, and architectural gear ratios (AGR) was larger during SEE lengthening. Under the present testing conditions, former ATR patients had recovered a relatively symmetrical walking gait pattern. Differences in seen AGR seem to accommodate the profound changes in MTU architecture, limiting the required fascicle shortening velocity. Overall, the contractile behavior of the GM fascicles does not restrict length- or velocity-dependent force potentials during this locomotor task.
KW  - tendon rupture
KW  - muscle fascicle behavior
KW  - walking gait
KW  - force generation
KW  - ultrasound imaging
Y1  - 2022
U6  - https://doi.org/10.3389/fphys.2022.792576
SN  - 1664-042X
VL  - 13
PB  - Frontiers Research Foundation
CY  - Lausanne
ER  - 
TY  - JOUR
A1  - Quittmann, Oliver J.
A1  - Abel, Thomas
A1  - Albracht, Kirsten
A1  - Strüder, Heiko K.
T1  - Biomechanics of all-out handcycling exercise: kinetics, kinematics and muscular activity of a 15-s sprint test in able-bodied participants
JF  - Sports Biomechanics
N2  - This study aims to quantify the kinematics, kinetics and muscular activity of all-out handcycling exercise and examine their alterations during the course of a 15-s sprint test. Twelve able-bodied competitive triathletes performed a 15-s all-out sprint test in a recumbent racing handcycle that was attached to an ergometer. During the sprint test, tangential crank kinetics, 3D joint kinematics and muscular activity of 10 muscles of the upper extremity and trunk were examined using a power metre, motion capturing and surface electromyography (sEMG), respectively. Parameters were compared between revolution one (R1), revolution two (R2), the average of revolution 3 to 13 (R3) and the average of the remaining revolutions (R4). Shoulder abduction and internal-rotation increased, whereas maximal shoulder retroversion decreased during the sprint. Except for the wrist angles, angular velocity increased for every joint of the upper extremity. Several muscles demonstrated an increase in muscular activation, an earlier onset of muscular activation in crank cycle and an increased range of activation. During the course of a 15-s all-out sprint test in handcycling, the shoulder muscles and the muscles associated to the push phase demonstrate indications for short-duration fatigue. These findings are helpful to prevent injuries and improve performance in all-out handcycling.
KW  - Handbike
KW  - sEMG
KW  - Paralympic sport
KW  - performance testing
KW  - high-intensity exercise
Y1  - 2022
U6  - https://doi.org/10.1080/14763141.2020.1745266
SN  - 1752-6116 (Onlineausgabe)
SN  - 1476-3141 (Druckausgabe)
VL  - 21
IS  - 10
SP  - 1200
EP  - 1223
PB  - Taylor & Francis
CY  - London
ER  - 
TY  - JOUR
A1  - Kleefeld, Andreas
A1  - Zimmermann, M.
ED  - Constanda, Christian
ED  - Bodmann, Bardo E.J.
ED  - Harris, Paul J.
T1  - Computing Elastic Interior Transmission Eigenvalues
JF  - Integral Methods in Science and Engineering
N2  - An alternative method is presented to numerically compute interior elastic transmission eigenvalues for various domains in two dimensions. This is achieved by discretizing the resulting system of boundary integral equations in combination with a nonlinear eigenvalue solver. Numerical results are given to show that this new approach can provide better results than the finite element method when dealing with general domains.
Y1  - 2022
SN  - 978-3-031-07171-3
U6  - https://doi.org/10.1007/978-3-031-07171-3_10
N1  - Corresponding author: Andreas Kleefeld
SP  - 139
EP  - 155
PB  - Birkhäuser
CY  - Cham
ER  - 
TY  - CHAP
A1  - Burgeth, Bernhard
A1  - Kleefeld, Andreas
A1  - Zhang, Eugene
A1  - Zhang, Yue
ED  - Baudrier, Étienne
ED  - Naegel, Benoît
ED  - Krähenbühl, Adrien
ED  - Tajine, Mohamed
T1  - Towards Topological Analysis of Non-symmetric Tensor Fields via Complexification
T2  - Discrete Geometry and Mathematical Morphology
N2  - Fields of asymmetric tensors play an important role in many applications such as medical imaging (diffusion tensor magnetic resonance imaging), physics, and civil engineering (for example Cauchy-Green-deformation tensor, strain tensor with local rotations, etc.). However, such asymmetric tensors are usually symmetrized and then further processed. Using this procedure results in a loss of information. A new method for the processing of asymmetric tensor fields is proposed restricting our attention to tensors of second-order given by a 2x2 array or matrix with real entries. This is achieved by a transformation resulting in Hermitian matrices that have an eigendecomposition similar to symmetric matrices. With this new idea numerical results for real-world data arising from a deformation of an object by external forces are given. It is shown that the asymmetric part indeed contains valuable information.
Y1  - 2022
SN  - 978-3-031-19897-7
U6  - https://doi.org/10.1007/978-3-031-19897-7_5
N1  - Second International Joint Conference, DGMM 2022, Strasbourg, France, October 24–27, 2022
N1  - Corresponding author: Andreas Kleefeld
SP  - 48
EP  - 59
PB  - Springer
CY  - Cham
ER  - 
TY  - JOUR
A1  - Harris, Isaac
A1  - Kleefeld, Andreas
T1  - Analysis and computation of the transmission eigenvalues with a conductive boundary condition
JF  - Applicable Analysis
N2  - We provide a new analytical and computational study of the transmission eigenvalues with a conductive boundary condition. These eigenvalues are derived from the scalar inverse scattering problem for an inhomogeneous material with a conductive boundary condition. The goal is to study how these eigenvalues depend on the material parameters in order to estimate the refractive index. The analytical questions we study are: deriving Faber–Krahn type lower bounds, the discreteness and limiting behavior of the transmission eigenvalues as the conductivity tends to infinity for a sign changing contrast. We also provide a numerical study of a new boundary integral equation for computing the eigenvalues. Lastly, using the limiting behavior we will numerically estimate the refractive index from the eigenvalues provided the conductivity is sufficiently large but unknown.
KW  - Boundary integral equations
KW  - Inverse spectral problem
KW  - Conductive boundary condition
KW  - Transmission eigenvalues
Y1  - 2020
U6  - https://doi.org/10.1080/00036811.2020.1789598
SN  - 1563-504X
VL  - 101
IS  - 6
SP  - 1880
EP  - 1895
PB  - Taylor & Francis
CY  - London
ER  - 
TY  - JOUR
A1  - Engelmann, Ulrich M.
A1  - Shalaby, Ahmed
A1  - Shasha, Carolyn
A1  - Krishnan, Kannan M.
A1  - Krause, Hans-Joachim
T1  - Comparative modeling of frequency mixing measurements of magnetic nanoparticles using micromagnetic simulations and Langevin theory
JF  - Nanomaterials
N2  - Dual frequency magnetic excitation of magnetic nanoparticles (MNP) enables enhanced biosensing applications. This was studied from an experimental and theoretical perspective: nonlinear sum-frequency components of MNP exposed to dual-frequency magnetic excitation were measured as a function of static magnetic offset field. The Langevin model in thermodynamic equilibrium was fitted to the experimental data to derive parameters of the lognormal core size distribution. These parameters were subsequently used as inputs for micromagnetic Monte-Carlo (MC)-simulations. From the hysteresis loops obtained from MC-simulations, sum-frequency components were numerically demodulated and compared with both experiment and Langevin model predictions. From the latter, we derived that approximately 90% of the frequency mixing magnetic response signal is generated by the largest 10% of MNP. We therefore suggest that small particles do not contribute to the frequency mixing signal, which is supported by MC-simulation results. Both theoretical approaches describe the experimental signal shapes well, but with notable differences between experiment and micromagnetic simulations. These deviations could result from Brownian relaxations which are, albeit experimentally inhibited, included in MC-simulation, or (yet unconsidered) cluster-effects of MNP, or inaccurately derived input for MC-simulations, because the largest particles dominate the experimental signal but concurrently do not fulfill the precondition of thermodynamic equilibrium required by Langevin theory.
KW  - Magnetic nanoparticles
KW  - Frequency mixing magnetic detection
KW  - Langevin theory
KW  - Micromagnetic simulation
KW  - Nonequilibrium dynamics
Y1  - 2021
SN  - 2079-4991
U6  - https://doi.org/10.3390/nano11051257
N1  - This article belongs to the Special Issue Applications and Properties of Magnetic Nanoparticles
VL  - 11
IS  - 5
SP  - 1
EP  - 16
PB  - MDPI
CY  - Basel
ER  - 
TY  - JOUR
A1  - Grieger, Niklas
A1  - Schwabedal, Justus T. C.
A1  - Wendel, Stefanie
A1  - Ritze, Yvonne
A1  - Bialonski, Stephan
T1  - Automated scoring of pre-REM sleep in mice with deep learning
JF  - Scientific Reports
N2  - Reliable automation of the labor-intensive manual task of scoring animal sleep can facilitate the analysis of long-term sleep studies. In recent years, deep-learning-based systems, which learn optimal features from the data, increased scoring accuracies for the classical sleep stages of Wake, REM, and Non-REM. Meanwhile, it has been recognized that the statistics of transitional stages such as pre-REM, found between Non-REM and REM, may hold additional insight into the physiology of sleep and are now under vivid investigation. We propose a classification system based on a simple neural network architecture that scores the classical stages as well as pre-REM sleep in mice. When restricted to the classical stages, the optimized network showed state-of-the-art classification performance with an out-of-sample F1 score of 0.95 in male C57BL/6J mice. When unrestricted, the network showed lower F1 scores on pre-REM (0.5) compared to the classical stages. The result is comparable to previous attempts to score transitional stages in other species such as transition sleep in rats or N1 sleep in humans. Nevertheless, we observed that the sequence of predictions including pre-REM typically transitioned from Non-REM to REM reflecting sleep dynamics observed by human scorers. Our findings provide further evidence for the difficulty of scoring transitional sleep stages, likely because such stages of sleep are under-represented in typical data sets or show large inter-scorer variability. We further provide our source code and an online platform to run predictions with our trained network.
Y1  - 2021
U6  - https://doi.org/10.1038/s41598-021-91286-0
SN  - 2045-2322
N1  - Corresponding author: Stephan Bialonski
VL  - 11
IS  - Art. 12245
PB  - Springer Nature
CY  - London
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  - https://doi.org/10.7712/120221.8041.19047
N1  - 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  - Ball, Christopher Stephen
A1  - Vögele, Stefan
A1  - Grajewski, Matthias
A1  - Kuckshinrichs, Wilhelm
T1  - E-mobility from a multi-actor point of view: Uncertainties and their impacts
JF  - Technological Forecasting and Social Change
Y1  - 2021
SN  - 0040-1625
U6  - https://doi.org/10.1016/j.techfore.2021.120925
VL  - 170
IS  - Art. 120925
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Poghossian, Arshak
A1  - Schöning, Michael Josef
T1  - Recent progress in silicon-based biologically sensitive field-effect devices
JF  - Current Opinion in Electrochemistry
N2  - Biologically sensitive field-effect devices (BioFEDs) advantageously combine the electronic field-effect functionality with the (bio)chemical receptor’s recognition ability for (bio)chemical sensing. In this review, basic and widely applied device concepts of silicon-based BioFEDs (ion-sensitive field-effect transistor, silicon nanowire transistor, electrolyte-insulator-semiconductor capacitor, light-addressable potentiometric sensor) are presented and recent progress (from 2019 to early 2021) is discussed. One of the main advantages of BioFEDs is the label-free sensing principle enabling to detect a large variety of biomolecules and bioparticles by their intrinsic charge. The review encompasses applications of BioFEDs for the label-free electrical detection of clinically relevant protein biomarkers, deoxyribonucleic acid molecules and viruses, enzyme-substrate reactions as well as recording of the cell acidification rate (as an indicator of cellular metabolism) and the extracellular potential.
Y1  - 2021
U6  - https://doi.org/10.1016/j.coelec.2021.100811
SN  - 2451-9103
IS  - Article number: 100811
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Hugenroth, Kristin
A1  - Borchardt, Ralf
A1  - Ritter, Philine
A1  - Groß‑Hardt, Sascha
A1  - Meyns, Bart
A1  - Verbelen, Tom
A1  - Steinseifer, Ulrich
A1  - Kaufmann, Tim A. S.
A1  - Engelmann, Ulrich M.
T1  - Optimizing cerebral perfusion and hemodynamics during cardiopulmonary bypass through cannula design combining in silico, in vitro and in vivo input
JF  - Scientific Reports
N2  - Cardiopulmonary bypass (CPB) is a standard technique for cardiac surgery, but comes with the risk of severe neurological complications (e.g. stroke) caused by embolisms and/or reduced cerebral perfusion. We report on an aortic cannula prototype design (optiCAN) with helical outflow and jet-splitting dispersion tip that could reduce the risk of embolic events and restores cerebral perfusion to 97.5% of physiological flow during CPB in vivo, whereas a commercial curved-tip cannula yields 74.6%. In further in vitro comparison, pressure loss and hemolysis parameters of optiCAN remain unaffected. Results are reproducibly confirmed in silico for an exemplary human aortic anatomy via computational fluid dynamics (CFD) simulations. Based on CFD simulations, we firstly show that optiCAN design improves aortic root washout, which reduces the risk of thromboembolism. Secondly, we identify regions of the aortic intima with increased risk of plaque release by correlating areas of enhanced plaque growth and high wall shear stresses (WSS). From this we propose another easy-to-manufacture cannula design (opti2CAN) that decreases areas burdened by high WSS, while preserving physiological cerebral flow and favorable hemodynamics. With this novel cannula design, we propose a cannulation option to reduce neurological complications and the prevalence of stroke in high-risk patients after CPB.
Y1  - 2021
U6  - https://doi.org/10.1038/s41598-021-96397-2
SN  - 2045-2322
VL  - 11
IS  - Art. No. 16800
SP  - 1
EP  - 12
PB  - Springer
CY  - Berlin
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  - https://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  - https://doi.org/10.1111/aor.14046
SN  - 1525-1594
VL  - 45
IS  - 12
SP  - 1513
EP  - 1521
PB  - Wiley
CY  - Weinheim
ER  -