@article{JansenBehbahaniLaumenetal.2010, author = {Jansen, Sebastian and Behbahani, Mehdi and Laumen, Marco and Kaufmann, Tim and Hormes, Marcus and Schmitz-Rode, Thomas and Behr, Marek and Steinseifer, Ulrich}, title = {3D Stereo-PIV Validation for CFD-Simulation of Steady Flow through the Human Aorta using Rapid-Prototyping techniques}, year = {2010}, language = {en} } @article{JayaramanMummidisettyLoeschetal.2019, author = {Jayaraman, Chandrasekaran and Mummidisetty, Chaitanya Krishna and Loesch, Alexandra and Kaur, Sandi and Hoppe-Ludwig, Shenan and Staat, Manfred and Jayaraman, Arun}, title = {Postural and metabolic benefits of using a forearm support walker in older adults with impairments}, series = {Archives of Physical Medicine and Rehabilitation}, volume = {Volume 100}, journal = {Archives of Physical Medicine and Rehabilitation}, number = {Issue 4}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0003-9993}, doi = {10.1016/j.apmr.2018.10.001}, pages = {638 -- 647}, year = {2019}, language = {en} } @article{JiminezGermanBehbahaniMiettinenetal.2013, author = {Jiminez German, Salvador and Behbahani, Mehdi and Miettinen, Susanna and Grijpma, Dirk W. and Haimi, Suvi P.}, title = {Proliferation and differentiation of adipose stem cells towards smooth muscle cells on poly(trimethylene carbonate) membranes}, series = {Macromolecular symposia}, volume = {Vol. 334}, journal = {Macromolecular symposia}, number = {Iss. 1}, publisher = {Wiley}, address = {Weinheim}, issn = {0258-0322}, pages = {133 -- 142}, year = {2013}, language = {en} } @article{JungMuellerStaat2018, author = {Jung, Alexander and M{\"u}ller, Wolfram and Staat, Manfred}, title = {Wind and fairness in ski jumping: A computer modelling analysis}, series = {Journal of Biomechanics}, journal = {Journal of Biomechanics}, number = {75}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0021-9290}, doi = {10.1016/j.jbiomech.2018.05.001}, pages = {147 -- 153}, year = {2018}, abstract = {Wind is closely associated with the discussion of fairness in ski jumping. To counter-act its influence on the jump length, the International Ski Federation (FIS) has introduced a wind compensation approach. We applied three differently accurate computer models of the flight phase with wind (M1, M2, and M3) to study the jump length effects of various wind scenarios. The previously used model M1 is accurate for wind blowing in direction of the flight path, but inaccuracies are to be expected for wind directions deviating from the tangent to the flight path. M2 considers the change of airflow direction, but it does not consider the associated change in the angle of attack of the skis which additionally modifies drag and lift area time functions. M3 predicts the length effect for all wind directions within the plane of the flight trajectory without any mathematical simplification. Prediction errors of M3 are determined only by the quality of the input data: wind velocity, drag and lift area functions, take-off velocity, and weight. For comparing the three models, drag and lift area functions of an optimized reference jump were used. Results obtained with M2, which is much easier to handle than M3, did not deviate noticeably when compared to predictions of the reference model M3. Therefore, we suggest to use M2 in future applications. A comparison of M2 predictions with the FIS wind compensation system showed substantial discrepancies, for instance: in the first flight phase, tailwind can increase jump length, and headwind can decrease it; this is opposite of what had been anticipated before and is not considered in the current wind compensation system in ski jumping.}, language = {en} } @article{JungMuellerStaat2019, author = {Jung, Alexander and M{\"u}ller, Wolfram and Staat, Manfred}, title = {Optimization of the flight technique in ski jumping: the influence of wind}, number = {Early view}, publisher = {Elsevier}, address = {Amsterdam}, doi = {10.1016/j.jbiomech.2019.03.023}, year = {2019}, language = {en} } @article{JungStaat2019, author = {Jung, Alexander and Staat, Manfred}, title = {Modeling and simulation of human induced pluripotent stem cell-derived cardiac tissue}, series = {GAMM - Mitteilungen der Gesellschaft f{\"u}r Angewandte Mathematik und Mechanik}, volume = {42}, journal = {GAMM - Mitteilungen der Gesellschaft f{\"u}r Angewandte Mathematik und Mechanik}, number = {4}, publisher = {Wiley}, address = {Weinheim}, issn = {1522-2608}, doi = {10.1002/gamm.201900002}, pages = {11 Seiten}, year = {2019}, language = {en} } @article{JungStaat2020, author = {Jung, Alexander and Staat, Manfred}, title = {Erratum to "Modeling and simulation of human induced pluripotent stem cell-derived cardiac tissue" [GAMM-Mitteilungen, (2019), 42, 4, 10.1002/gamm.201900002]}, series = {GAMM-Mitteilungen}, volume = {43}, journal = {GAMM-Mitteilungen}, number = {4}, publisher = {Wiley-VCH GmbH}, address = {Weinheim}, issn = {1522-2608}, doi = {10.1002/gamm.202000011}, year = {2020}, language = {en} } @article{JungStaatMueller2013, author = {Jung, Alexander and Staat, Manfred and M{\"u}ller, Wolfram}, title = {Flight style optimization in ski jumping on normal, large, and ski flying hills}, series = {Journal of biomechanics}, volume = {Vol. 47}, journal = {Journal of biomechanics}, number = {Iss. 3}, publisher = {Elsevier}, address = {Amsterdam}, issn = {1873-2380 (E-Journal); 0021-9290 (Print)}, pages = {716 -- 722}, year = {2013}, language = {en} } @article{JungStaatMueller2018, author = {Jung, Alexander and Staat, Manfred and M{\"u}ller, Wolfram}, title = {Corrigendum to "Flight style optimization in ski jumping on normal, large, and ski flying hills" [J. Biomech 47 (2014) 716-722]}, series = {Journals of Biomechanics}, journal = {Journals of Biomechanics}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0021-9290}, doi = {10.1016/j.jbiomech.2018.02.001}, pages = {313}, year = {2018}, language = {en} } @article{KaramanidisAlbrachtBraunsteinetal.2011, author = {Karamanidis, Kiros and Albracht, Kirsten and Braunstein, Bjoern and Catala, Maria Moreno and Goldmann, Jan-Peter and Br{\"u}ggemann, Gert-Peter}, title = {Lower leg musculoskeletal geometry and sprint performance}, series = {Gait and Posture}, volume = {34}, journal = {Gait and Posture}, number = {1}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0966-6362}, doi = {10.1016/j.gaitpost.2011.03.009}, pages = {138 -- 141}, year = {2011}, abstract = {The purpose of this study was to investigate whether sprint performance is related to lower leg musculoskeletal geometry within a homogeneous group of highly trained 100-m sprinters. Using a cluster analysis, eighteen male sprinters were divided into two groups based on their personal best (fast: N = 11, 10.30 ± 0.07 s; slow: N = 7, 10.70 ± 0.08 s). Calf muscular fascicle arrangement and Achilles tendon moment arms (calculated by the gradient of tendon excursion versus ankle joint angle) were analyzed for each athlete using ultrasonography. Achilles tendon moment arm, foot and ankle skeletal geometry, fascicle arrangement as well as the ratio of fascicle length to Achilles tendon moment arm showed no significant (p > 0.05) correlation with sprint performance, nor were there any differences in the analyzed musculoskeletal parameters between the fast and slow sprinter group. Our findings provide evidence that differences in sprint ability in world-class athletes are not a result of differences in the geometrical design of the lower leg even when considering both skeletal and muscular components.}, language = {en} } @article{KaulKoshkaryevArtmannetal.2008, author = {Kaul, D. K. and Koshkaryev, A. and Artmann, Gerhard and Barshtein, G. and Yedgar, S.}, title = {Additive effect of red blood cell rigidity and adherence to endothelial cells in inducing vascular resistance}, series = {American Journal of Physiology : Heart and Circulation Physiology . 295 (2008), H. 4}, volume = {295}, journal = {American Journal of Physiology : Heart and Circulation Physiology . 295 (2008), H. 4}, number = {4}, issn = {1522-1539}, pages = {H1788 -- H1793}, year = {2008}, language = {en} } @article{KetelhutBrueggeGoelletal.2020, author = {Ketelhut, Maike and Br{\"u}gge, G. M. and G{\"o}ll, Fabian and Braunstein, Bjoern and Albracht, Kirsten and Abel, Dirk}, title = {Adaptive iterative learning control of an industrial robot during neuromuscular training}, series = {IFAC PapersOnLine}, volume = {53}, journal = {IFAC PapersOnLine}, number = {2}, publisher = {Elsevier}, address = {Amsterdam}, issn = {2405-8963}, doi = {10.1016/j.ifacol.2020.12.741}, pages = {16468 -- 16475}, year = {2020}, abstract = {To prevent the reduction of muscle mass and loss of strength coming along with the human aging process, regular training with e.g. a leg press is suitable. However, the risk of training-induced injuries requires the continuous monitoring and controlling of the forces applied to the musculoskeletal system as well as the velocity along the motion trajectory and the range of motion. In this paper, an adaptive norm-optimal iterative learning control algorithm to minimize the knee joint loadings during the leg extension training with an industrial robot is proposed. The response of the algorithm is tested in simulation for patients with varus, normal and valgus alignment of the knee and compared to the results of a higher-order iterative learning control algorithm, a robust iterative learning control and a recently proposed conventional norm-optimal iterative learning control algorithm. Although significant improvements in performance are made compared to the conventional norm-optimal iterative learning control algorithm with a small learning factor, for the developed approach as well as the robust iterative learning control algorithm small steady state errors occur.}, language = {en} } @article{KetelhutGoellBraunsteinetal.2018, author = {Ketelhut, Maike and G{\"o}ll, Fabian and Braunstein, Bj{\"o}rn and Albracht, Kirsten and Abel, Dirk}, title = {Comparison of different training algorithms for the leg extension training with an industrial robot}, series = {Current Directions in Biomedical Engineering}, volume = {4}, journal = {Current Directions in Biomedical Engineering}, number = {1}, publisher = {De Gruyter}, address = {Berlin}, issn = {2364-5504}, doi = {10.1515/cdbme-2018-0005}, pages = {17 -- 20}, year = {2018}, abstract = {In the past, different training scenarios have been developed and implemented on robotic research platforms, but no systematic analysis and comparison have been done so far. This paper deals with the comparison of an isokinematic (motion with constant velocity) and an isotonic (motion against constant weight) training algorithm. Both algorithms are designed for a robotic research platform consisting of a 3D force plate and a high payload industrial robot, which allows leg extension training with arbitrary six-dimensional motion trajectories. In the isokinematic as well as the isotonic training algorithm, individual paths are defined i n C artesian s pace by sufficient s upport p oses. I n t he i sotonic t raining s cenario, the trajectory is adapted to the measured force as the robot should only move along the trajectory as long as the force applied by the user exceeds a minimum threshold. In the isotonic training scenario however, the robot's acceleration is a function of the force applied by the user. To validate these findings, a simulative experiment with a simple linear trajectory is performed. For this purpose, the same force path is applied in both training scenarios. The results illustrate that the algorithms differ in the force dependent trajectory adaption.}, language = {en} } @article{KetelhutKolditzGoelletal.2019, author = {Ketelhut, Maike and Kolditz, Melanie and G{\"o}ll, Fabian and Braunstein, Bjoern and Albracht, Kirsten and Abel, Dirk}, title = {Admittance control of an industrial robot during resistance training}, series = {IFAC-PapersOnLine}, volume = {52}, journal = {IFAC-PapersOnLine}, number = {19}, publisher = {Elsevier}, address = {Amsterdam}, issn = {2405-8963}, doi = {10.1016/j.ifacol.2019.12.102}, pages = {223 -- 228}, year = {2019}, abstract = {Neuromuscular strength training of the leg extensor muscles plays an important role in the rehabilitation and prevention of age and wealth related diseases. In this paper, we focus on the design and implementation of a Cartesian admittance control scheme for isotonic training, i.e. leg extension and flexion against a predefined weight. For preliminary testing and validation of the designed algorithm an experimental research and development platform consisting of an industrial robot and a force plate mounted at its end-effector has been used. Linear, diagonal and arbitrary two-dimensional motion trajectories with different weights for the leg extension and flexion part are applied. The proposed algorithm is easily adaptable to trajectories consisting of arbitrary six-dimensional poses and allows the implementation of individualized trajectories.}, language = {en} } @article{KezerashviliDachwald2021, author = {Kezerashvili, Roman Ya and Dachwald, Bernd}, title = {Preface: Solar sailing: Concepts, technology, and missions II}, series = {Advances in Space Research}, volume = {67}, journal = {Advances in Space Research}, number = {9}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0273-1177}, doi = {10.1016/j.asr.2021.01.037}, pages = {2559 -- 2560}, year = {2021}, language = {en} } @article{KnoxBruggemannGossmannetal.2020, author = {Knox, Ronald and Bruggemann, Andrea and Gossmann, Matthias and Thomas, Ulrich and Horv{\´a}th, Andr{\´a}s and Dragicevic, Elena and Stoelzle-Feix, Sonja and Fertig, Niels and Jung, Alexander and Raman, Aravind Hariharan and Staat, Manfred and Linder, Peter}, title = {Combining physiological relevance and throughput for in vitro cardiac contractility measurement}, series = {Biophysical Journal}, volume = {118}, journal = {Biophysical Journal}, number = {Issue 3, Supplement 1}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0006-3495}, doi = {10.1016/j.bpj.2019.11.3104}, pages = {570a}, year = {2020}, abstract = {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.}, language = {en} } @article{KodomskoiKotliarSchroederetal.2019, author = {Kodomskoi, Leonid and Kotliar, Konstantin and Schr{\"o}der, Andreas and Weiss, Michael and Hille, Konrad}, title = {Suture-Probe Canaloplasty as an Alternative to Canaloplasty using the iTrack™ Microcatheter}, series = {Journal of Glaucoma}, journal = {Journal of Glaucoma}, number = {Epub ahead of print}, publisher = {Lippincott Williams \& Wilkins}, address = {Philadelphia}, issn = {1057-0829}, doi = {10.1097/IJG.0000000000001321}, year = {2019}, language = {en} } @article{KolditzAlbinAbeletal.2016, author = {Kolditz, Melanie and Albin, Thivaharan and Abel, Dirk and Fasse, Alessandro and Br{\"u}ggemann, Gert-Peter and Albracht, Kirsten}, title = {Evaluation of foot position and orientation as manipulated variables to control external knee adduction moments in leg extension training}, series = {Computer methods and programs in biomedicine}, volume = {171}, journal = {Computer methods and programs in biomedicine}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0169-2607}, doi = {10.1016/j.cmpb.2016.09.005}, pages = {81 -- 86}, year = {2016}, abstract = {Background and Objective Effective leg extension training at a leg press requires high forces, which need to be controlled to avoid training-induced damage. In order to avoid high external knee adduction moments, which are one reason for unphysiological loadings on knee joint structures, both training movements and the whole reaction force vector need to be observed. In this study, the applicability of lateral and medial changes in foot orientation and position as possible manipulated variables to control external knee adduction moments is investigated. As secondary parameters both the medio-lateral position of the center of pressure and the frontal-plane orientation of the reaction force vector are analyzed. Methods Knee adduction moments are estimated using a dynamic model of the musculoskeletal system together with the measured reaction force vector and the motion of the subject by solving the inverse kinematic and dynamic problem. Six different foot conditions with varying positions and orientations of the foot in a static leg press are evaluated and compared to a neutral foot position. Results Both lateral and medial wedges under the foot and medial and lateral shifts of the foot can influence external knee adduction moments in the presented study with six healthy subjects. Different effects are observed with the varying conditions: the pose of the leg is changed and the direction and center of pressure of the reaction force vector is influenced. Each effect results in a different direction or center of pressure of the reaction force vector. Conclusions The results allow the conclusion that foot position and orientation can be used as manipulated variables in a control loop to actively control knee adduction moments in leg extension training.}, language = {en} } @article{KonstantinidisFloresMartinezDachwaldetal.2015, author = {Konstantinidis, Konstantinos and Flores Martinez, Claudio and Dachwald, Bernd and Ohndorf, Andreas and Dykta, Paul and Bowitz, Pascal and Rudolph, Martin and Digel, Ilya and Kowalski, Julia and Voigt, Konstantin and F{\"o}rstner, Roger}, title = {A lander mission to probe subglacial water on Saturn's moon enceladus for life}, series = {Acta astronautica}, volume = {Vol. 106}, journal = {Acta astronautica}, publisher = {Elsevier}, address = {Amsterdam}, issn = {1879-2030 (E-Journal); 0094-5765 (Print)}, pages = {63 -- 89}, year = {2015}, language = {en} } @article{KoppSchmeetsGosauetal.2019, author = {Kopp, Alexander and Schmeets, Ralf and Gosau, Martin and Friedrich, Reinhard E. and Fuest, Sandra and Behbahani, Mehdi and Barbeck, Mike and Rutkowski, Rico and Burg, Simon and Kluwe, Lan and Henningsen, Anders}, title = {Production and Characterization of Porous Fibroin Scaffolds for Regenerative Medical Application}, series = {In Vivo}, volume = {33}, journal = {In Vivo}, number = {3}, issn = {1791-7549}, doi = {10.21873/invivo.11536}, pages = {757 -- 762}, year = {2019}, language = {en} }