@article{ProbstBehbahaniBorrmannetal.2010, author = {Probst, M. and Behbahani, Mehdi and Borrmann, E. and Elgeti, S. and Nicolai, M. and Behr, Marek}, title = {Hemodynamic Modeling for Numerical Analysis and Design of Medical Devices}, year = {2010}, language = {en} } @article{EschSalberWoltersetal.2002, author = {Esch, Thomas and Salber, Wolfgang and Wolters, Peter and Geiger, Jos{\´e} and Dilthey, Jochen}, title = {Synergies of variable valve actuation and direct injection}, series = {Direct injection SI engine technology 2002 : [SAE 2002 world congress, Detroit, Michigan, USA, March 4 - 7, 2002].}, journal = {Direct injection SI engine technology 2002 : [SAE 2002 world congress, Detroit, Michigan, USA, March 4 - 7, 2002].}, publisher = {Society of Automotive Engineers}, address = {Warrendale, Pa}, isbn = {0-7680-0961-8}, pages = {45 -- 53}, year = {2002}, language = {en} } @article{BehbahaniMaiBergmannetal.2010, author = {Behbahani, Mehdi and Mai, A. and Bergmann, B. and Waluga, C. and Behr, Marek and Tran, L. and Vonderstein, K. and Mottaghy, K.}, title = {Modeling and Numerical Simulation of Blood Damage}, year = {2010}, language = {en} } @article{BehbahaniProbstMaietal.2010, author = {Behbahani, Mehdi and Probst, M. and Mai, A. and Behr, Marek and Tran, L. and Vonderstein, K. and Mottaghy, K.}, title = {Numerical Prediction of Blood Damage in Biomedical Devices}, year = {2010}, language = {en} } @article{BehbahaniWalugaStocketal.2009, author = {Behbahani, Mehdi and Waluga, C. and Stock, S. and Mai, A. and Bergmann, B. and Behr, Marek and Tran, L. and Vonderstein, K. and Scheidt, H. and Oedekoven, B. and Mottaghy, K.}, title = {Modelling and Numerical Analysis of Platelet Reactions and Surface Thrombus Growth}, year = {2009}, language = {en} } @article{MartinVaqueroKleefeld2020, author = {Mart{\´i}n-Vaquero, J. and Kleefeld, Andreas}, title = {Solving nonlinear parabolic PDEs in several dimensions: Parallelized ESERK codes}, series = {Journal of Computational Physics}, journal = {Journal of Computational Physics}, number = {423}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0021-9991}, doi = {10.1016/j.jcp.2020.109771}, year = {2020}, abstract = {There is a very large number of very important situations which can be modeled with nonlinear parabolic partial differential equations (PDEs) in several dimensions. In general, these PDEs can be solved by discretizing in the spatial variables and transforming them into huge systems of ordinary differential equations (ODEs), which are very stiff. Therefore, standard explicit methods require a large number of iterations to solve stiff problems. But implicit schemes are computationally very expensive when solving huge systems of nonlinear ODEs. Several families of Extrapolated Stabilized Explicit Runge-Kutta schemes (ESERK) with different order of accuracy (3 to 6) are derived and analyzed in this work. They are explicit methods, with stability regions extended, along the negative real semi-axis, quadratically with respect to the number of stages s, hence they can be considered to solve stiff problems much faster than traditional explicit schemes. Additionally, they allow the adaptation of the step length easily with a very small cost. Two new families of ESERK schemes (ESERK3 and ESERK6) are derived, and analyzed, in this work. Each family has more than 50 new schemes, with up to 84.000 stages in the case of ESERK6. For the first time, we also parallelized all these new variable step length and variable number of stages algorithms (ESERK3, ESERK4, ESERK5, and ESERK6). These parallelized strategies allow to decrease times significantly, as it is discussed and also shown numerically in two problems. Thus, the new codes provide very good results compared to other well-known ODE solvers. Finally, a new strategy is proposed to increase the efficiency of these schemes, and it is discussed the idea of combining ESERK families in one code, because typically, stiff problems have different zones and according to them and the requested tolerance the optimum order of convergence is different.}, language = {en} } @article{UysalFiratCreutzetal.2022, author = {Uysal, Karya and Firat, Ipek Serat and Creutz, Till and Aydin, Inci Cansu and Artmann, Gerhard and Teusch, Nicole and Temiz Artmann, Ayseg{\"u}l}, title = {A novel in vitro wound healing assay using free-standing, ultra-thin PDMS membranes}, series = {membranes}, volume = {2023}, journal = {membranes}, number = {13(1)}, publisher = {MDPI}, address = {Basel}, doi = {10.3390/membranes13010022}, pages = {Artikel 22}, year = {2022}, abstract = {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.}, language = {en} } @misc{DieringerRenzLindeletal.2010, author = {Dieringer, Matthias A. and Renz, Wolfgang and Lindel, Tomasz Dawid and Seifert, Frank and Frauenrath, Tobias and Waiczies, Helmar and von Knobelsdorff-Brenkhoff, Florian and Santoro, Davide and Hoffmann, Werner and Ittermann, Bernd and Schulz-Menger, Jeanette and Niendorf, Thoralf}, title = {4CH TX/RX Surface Coil for 7T: Design, Optimization and Application for Cardiac Function Imaging}, series = {2010 ISMRM-ESMRMB joint annual meeting}, journal = {2010 ISMRM-ESMRMB joint annual meeting}, issn = {1545-4428}, year = {2010}, abstract = {Practical impediments of ultra high field cardiovascular MR (CVMR) can be catalogued in exacerbated magnetic field and radio frequency (RF) inhomogeneities, susceptibility and off-resonance effects, conductive and dielectric effects in tissue, and RF power deposition constraints, which all bear the potential to spoil the benefit of CVMR at 7T. Therefore, a four element cardiac transceive surface coil array was developed. Cardiac imaging provided clinically acceptable signal homogeneity with an excellent blood myocardium contrast. Subtle anatomic structures, such as pericardium, mitral and tricuspid valves and their apparatus, papillary muscles, and trabecles were accurately delineated.}, language = {en} } @inproceedings{SchmitzApandiSpillneretal.2024, author = {Schmitz, Annika and Apandi, Shah Eiman Amzar Shah and Spillner, Jan and Hima, Flutura and Behbahani, Mehdi}, title = {Effect of different cannula positions in the pulmonary artery on blood flow and gas exchange using computational fluid dynamics analysis}, series = {YRA MedTech Symposium (2024)}, booktitle = {YRA MedTech Symposium (2024)}, editor = {Digel, Ilya and Staat, Manfred and Trzewik, J{\"u}rgen and Sielemann, Stefanie and Erni, Daniel and Zylka, Waldemar}, publisher = {Universit{\"a}t Duisburg-Essen}, address = {Duisburg}, organization = {MedTech Symposium}, isbn = {978-3-940402-65-3}, doi = {10.17185/duepublico/81475}, pages = {29 -- 30}, year = {2024}, abstract = {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.}, language = {en} } @incollection{Kleefeld2020, author = {Kleefeld, Andreas}, title = {Numerical calculation of interior transmission eigenvalues with mixed boundary conditions}, series = {Computational and Analytic Methods in Science and Engineering}, booktitle = {Computational and Analytic Methods in Science and Engineering}, editor = {Constanda, Christian}, publisher = {Birkh{\"a}user}, address = {Cham}, isbn = {978-3-030-48185-8 (Hardcover)}, doi = {10.1007/978-3-030-48186-5_9}, pages = {173 -- 195}, year = {2020}, abstract = {Interior transmission eigenvalue problems for the Helmholtz equation play an important role in inverse wave scattering. Some distribution properties of those eigenvalues in the complex plane are reviewed. Further, a new scattering model for the interior transmission eigenvalue problem with mixed boundary conditions is described and an efficient algorithm for computing the interior transmission eigenvalues is proposed. Finally, extensive numerical results for a variety of two-dimensional scatterers are presented to show the validity of the proposed scheme.}, language = {en} }