TY - CHAP A1 - Borggrafe, Andreas A1 - Ohndorf, Andreas A1 - Dachwald, Bernd A1 - Seboldt, Wolfgang T1 - Analysis of interplanetary solar sail trajectories with attitude dynamics T2 - Dynamics and Control of Space Systems 2012 N2 - We present a new approach to the problem of optimal control of solar sails for low-thrust trajectory optimization. The objective was to find the required control torque magnitudes in order to steer a solar sail in interplanetary space. A new steering strategy, controlling the solar sail with generic torques applied about the spacecraft body axes, is integrated into the existing low-thrust trajectory optimization software InTrance. This software combines artificial neural networks and evolutionary algorithms to find steering strategies close to the global optimum without an initial guess. Furthermore, we implement a three rotational degree-of-freedom rigid-body attitude dynamics model to represent the solar sail in space. Two interplanetary transfers to Mars and Neptune are chosen to represent typical future solar sail mission scenarios. The results found with the new steering strategy are compared to the existing reference trajectories without attitude dynamics. The resulting control torques required to accomplish the missions are investigated, as they pose the primary requirements to a real on-board attitude control system. Y1 - 2012 SN - 978-0-87703-587-9 SP - 1553 EP - 1569 PB - Univelt Inc CY - San Diego ER - TY - JOUR A1 - Loeb, Horst Wolfgang A1 - Schartner, Karl-Heinz A1 - Dachwald, Bernd A1 - Ohndorf, Andreas A1 - Seboldt, Wolfgang T1 - Interstellar heliopause probe JF - Труды МАИ N2 - There is common agreement within the scientific community that in order to understand our local galactic environment it will be necessary to send a spacecraft into the region beyond the solar wind termination shock. Considering distances of 200 AU for a new mission, one needs a spacecraft traveling at a speed of close to 10 AU/yr in order to keep the mission duration in the range of less than 25 yrs, a transfer time postulated by European Space Agency (ESA). Two propulsion options for the mission have been proposed and discussed so far: the solar sail propulsion and the ballistic/radioisotope-electric propulsion (REP). As a further alternative, we here investigate a combination of solar-electric propulsion (SEP) and REP. The SEP stage consists of six 22-cms diameter RIT-22 ion thrusters working with a high specific impulse of 7377 s corresponding to a positive grid voltage of 5 kV. Solar power of 53 kW at begin of mission (BOM) is provided by a lightweight solar array. Y1 - 2012 IS - 60 SP - 2 EP - 2 PB - Moskauer Staatliches Luftfahrtinstitut (МАИ) CY - Moskau ER - TY - CHAP A1 - Duong, Minh Tuan A1 - Nguyen, Nhu Huynh A1 - Staat, Manfred ED - Eberhardsteiner, J. T1 - Numerical stability enhancement of modeling hyperelastic materials T2 - Proceedings European Congress on Computational Methods in Applied Sciences and Engineering (ECCOMAS 2012) Y1 - 2012 N1 - 6th European Congress on Computational Methods in Applied Sciences and Engineering (ECCOMAS 2012) Vienna, Austria, September 10-14, 2012 ER - TY - JOUR A1 - Hasan, Istabrak A1 - Keil, Ludger A1 - Staat, Manfred A1 - Wahl, Gerhard A1 - Bourauel, Christoph T1 - Determination of the frictional coefficient of the implant-antler interface : experimental approach JF - Biomedical Engineering / Biomedizinische Technik N2 - The similar bone structure of reindeer antler to human bone permits studying the osseointegration of dental implants in the jawbone. As the friction is one of the major factors that have a significant influence on the initial stability of immediately loaded dental implants, it is essential to define the frictional coefficient of the implant-antler interface. In this study, the kinetic frictional forces at the implant-antler interface were measured experimentally using an optomechanical setup and a stepping motor controller under different axial loads and sliding velocities. The corresponding mean values of the static and kinetic frictional coefficients were within the range of 0.5–0.7 and 0.3–0.5, respectively. An increase in the frictional forces with increasing applied axial loads was registered. The measurements showed an evidence of a decrease in the magnitude of the frictional coefficient with increasing sliding velocity. The results of this study provide a considerable assessment to clarify the suitable frictional coefficient to be used in the finite element contact analysis of antler specimens. Y1 - 2012 SN - 1862-278X VL - 57 IS - 5 SP - 359 EP - 363 PB - De Gruyter CY - Berlin ER - TY - CHAP A1 - Tran, Thanh Ngoc A1 - Staat, Manfred ED - Eberhardsteiner, J. T1 - A primal-dual shakedown analysis of 3D structures using the face-based smoothed finite element method T2 - Proceedings European Congress on Computational Methods in Applied Sciences and Engineering (ECCOMAS 2012) Y1 - 2012 N1 - 6th European Congress on Computational Methods in Applied Sciences and Engineering (ECCOMAS 2012) Vienna, Austria, September 10-14, 2012 ER - TY - CHAP A1 - Frotscher, Ralf A1 - Raatschen, Hans-Jürgen A1 - Staat, Manfred ED - Holzapfel, Gerhard A. T1 - Effectiveness of the edge-based smoothed finite element method applied to soft biological tissues T2 - ESMC-2012 - 8th European Solid Mechanics Conference, Graz, Austria, July 9-13, 2012 Y1 - 2012 SN - 978-3-85125-223-1 PB - Verlag d. Technischen Universität Graz CY - Graz ER - TY - CHAP A1 - Nix, Yvonne A1 - Frotscher, Ralf A1 - Staat, Manfred ED - Eberhardsteiner, J. T1 - Implementation of the edge-based smoothed extended finite element method T2 - Proceedings 6th European Congress on Computational Methods in Applied Sciences and Engineering (ECCOMAS 2012) Vienna, Austria, September 10-14, 2012 Y1 - 2012 ER - TY - CHAP A1 - Pham, Phu Tinh A1 - Nguyen, Thanh Ngoc A1 - Staat, Manfred T1 - FEM based shakedown analysis of hardening structures T2 - Proceedings International Conference on Advances in Computational Mechanics (ACOME) Y1 - 2012 N1 - International Conference on Advances in Computational Mechanics (ACOME), August 14-16, 2012, Ho Chi Minh City, Vietnam SP - 870 EP - 882 ER - TY - JOUR A1 - Staat, Manfred T1 - Limit and shakedown analysis under uncertainty JF - Tap chi Khoa hoc & ung dung - Dai hoc Ton Duc Thang Y1 - 2012 N1 - = Journal of Applied Sciences - Ton Duc Thang University VL - 19 SP - 45 EP - 47 ER - TY - BOOK A1 - Digel, Ilya A1 - Zhubanova, Azhar Ahmetovna A1 - Akimbekov, Nuraly S. T1 - Visual Virology Y1 - 2012 SN - 978-601-247-298-1 N1 - Text kasachisch, russisch, englisch CY - Almaty ER - TY - CHAP A1 - Frotscher, Ralf A1 - Raatschen, Hans-Jürgen A1 - Staat, Manfred ED - Eberhardsteiner, J. T1 - Application of an edge-based smoothed finite element method on geometrically non-linear plates of non-linear material T2 - Proceedings European Congress on Computational Methods in Applied Sciences and Engineering (ECCOMAS 2012) Y1 - 2012 N1 - 6th European Congress on Computational Methods in Applied Sciences and Engineering (ECCOMAS 2012) Vienna, Austria, September 10-14, 2012 ER - TY - JOUR A1 - Staat, Manfred A1 - Vu, Duc Khoi T1 - Limit analysis of flaws in pressurized pipes and cylindrical vessels Part II: Circumferential defects JF - Engineering Fracture Mechanics ; 97(2013), H. 1 N2 - Upper and lower bound theorems of limit analyses have been presented in part I of the paper. Part II starts with the finite element discretization of these theorems and demonstrates how both can be combined in a primal–dual optimization problem. This recently proposed numerical method is used to guide the development of a new class of closed-form limit loads for circumferential defects, which show that only large defects contribute to plastic collapse with a rapid loss of strength with increasing crack sizes. The formulae are compared with primal–dual FEM limit analyses and with burst tests. Even closer predictions are obtained with iterative limit load solutions for the von Mises yield function and for the Tresca yield function. Pressure loading of the faces of interior cracks in thick pipes reduces the collapse load of circumferential defects more than for axial flaws. Axial defects have been treated in part I of the paper. Y1 - 2012 U6 - https://doi.org/10.1016/j.engfracmech.2012.05.017 SN - 0013-7944 VL - 97 SP - 314 EP - 333 PB - Elsevier CY - Amsterdam ER - TY - BOOK A1 - Artmann, Gerhard T1 - Stem cell engineering : principles and applications / Gerhard M. Artmann ... eds. Y1 - 2011 SN - 978-3-642-11864-7 PB - Springer CY - Berlin [u.a.] ER - TY - JOUR A1 - Eijck, Lambert van A1 - Demmel, Franz A1 - Artmann, Gerhard A1 - Stadtler, Andreas Maximilian T1 - Macromolecular dynamics in red blood cells investigated using neutron spectroscopy JF - Journal of the Royal Society Interface Y1 - 2011 SN - 1742-5689 VL - 8 IS - 57 SP - 590 EP - 600 PB - The Royal Society CY - London ER - TY - JOUR A1 - Behbahani, Mehdi A1 - Tran, L. A1 - Jockenhövel, S. A1 - Behr, M. A1 - Mottaghy, K. T1 - Numerical prediction of thrombocyte reactions for application to a vascular flow model JF - British Journal of Surgery Y1 - 2011 SN - 1365-2168 N1 - 46th Congress of the European Society for Surgical Research, Aachen, Germany, 25-28 May 2011 ; ESSR Abstracts 2011 ; Oral Sessions OP10-5 VL - 98 IS - S5 SP - S17 PB - Oxford University Press CY - Oxford ER - TY - JOUR A1 - Kotliar, Konstantin A1 - Lanzl, Ines M. T1 - Can vascular function be assessed by the interpretation of retinal vascular diameter changes? JF - Investigative Ophthalmology & Visual Science, IOVS. 52 (2011), H. 1 Y1 - 2011 SN - 0146-0404 SP - 635 EP - 636 PB - ARVO CY - Rockville, Md. ER - TY - JOUR A1 - Lanzl, Ines M. A1 - Seidova, Seid-Fatima A1 - Maier, Mathias A1 - Schmidt-Trucksäss, Arno A1 - Halle, Martin A1 - Kotliar, Konstantin T1 - Dynamic retinal vessel response to flicker in age-related macular degeneration patients before and after vascular endothelial growth factor inhibitor injection JF - Acta Ophthalmologica Y1 - 2011 SN - 1755-3768 VL - 89 IS - 5 SP - 472 EP - 479 PB - Wiley CY - Weinheim ER - TY - JOUR A1 - Mikielewicz, Marek A1 - Kotliar, Konstantin A1 - Barraquer, Rafael I. A1 - Michael, Ralph T1 - Air-pulse corneal applanation signal curve parameters for the characterisation of keratoconus JF - British Journal of Ophthalmology (eBJO) Y1 - 2011 SN - 1468-2079 VL - 95 IS - 6 SP - 793 EP - 798 PB - BMJ Publ. Group CY - London ER - TY - JOUR A1 - Kotliar, Konstantin A1 - Baumann, Marcus A1 - Vilser, Walthard A1 - Lanzl, Ines M. T1 - Pulse wave velocity in retinal arteries of healthy volunteers JF - British Journal of Ophthalmology (eBJO) Y1 - 2011 SN - 1468-2079 VL - 95 IS - 11 SP - 675 EP - 679 PB - BMJ Publ. Group CY - London ER - TY - JOUR A1 - Kotliar, Konstantin A1 - Lanzl, Ines M. A1 - Schmidt-Trucksäss, A. A1 - Sitnikova, Diana A1 - Ali, Mohammad A1 - Blume, Katharina A1 - Halle, Martin A1 - Hansser, Henner T1 - Dynamic retinal vessel response to flicker in obesity: A methodological approach JF - Microvascular Research Y1 - 2011 SN - 0026-2862 VL - 81 IS - 1 SP - 123 EP - 128 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Dashevsky, Alexey V. A1 - Lanzl, Ines M. A1 - Kotliar, Konstantin T1 - Non-penetrating intracanalicular partial trabeculectomy via the ostia of Schlemm's canal JF - Graefe's Archive for Clinical and Experimental Ophthalmology Y1 - 2011 SN - 0721-832x VL - 249 IS - 4 SP - 565 EP - 573 PB - Springer CY - Berlin ER - TY - JOUR A1 - Hanssen, H. A1 - Nickel, T. A1 - Drexel, V. A1 - Hertel, G. A1 - Emslander, I. A1 - Sisic, Z. A1 - Lorang, D. A1 - Schuster, T. A1 - Kotliar, Konstantin A1 - Pressler, A. A1 - Schmidt-Trucksäss, A. A1 - Weis, M. A1 - Halle, M. T1 - Exercise-induced alterations of retinal vessel diameters and cardiovascular risk reduction in obesity JF - Atherosclerosis Y1 - 2011 SN - 0021-9150 VL - 216 IS - 2 SP - 433 EP - 439 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Doorschodt, B. M. A1 - Schreinemachers, M. C. J. M. A1 - Behbahani, Mehdi A1 - Florquin, S. A1 - Weis, J. A1 - Staat, Manfred A1 - Tolba, R. H. T1 - Hypothermic machine perfusion of kidney grafts: which pressure is preferred JF - Annals of Biomedical Engineering. 39 (2011), H. 3 Y1 - 2011 SN - 1573-9686 SP - 1051 EP - 1059 PB - Springer CY - Berlin ER - TY - CHAP A1 - Ohndorf, Andreas A1 - Dachwald, Bernd A1 - Seboldt, Wolfgang A1 - Schartner, Karl-Heinz T1 - Flight times to the heliopause using a combination of solar and radioisotope electric propulsion T2 - 32nd International Electric Propulsion Conference N2 - We investigate the interplanetary flight of a low-thrust space probe to the heliopause,located at a distance of about 200 AU from the Sun. Our goal was to reach this distance within the 25 years postulated by ESA for such a mission (which is less ambitious than the 15-year goal set by NASA). Contrary to solar sail concepts and combinations of allistic and electrically propelled flight legs, we have investigated whether the set flight time limit could also be kept with a combination of solar-electric propulsion and a second, RTG-powered upper stage. The used ion engine type was the RIT-22 for the first stage and the RIT-10 for the second stage. Trajectory optimization was carried out with the low-thrust optimization program InTrance, which implements the method of Evolutionary Neurocontrol,using Artificial Neural Networks for spacecraft steering and Evolutionary Algorithms to optimize the Neural Networks’ parameter set. Based on a parameter space study, in which the number of thrust units, the unit’s specific impulse, and the relative size of the solar power generator were varied, we have chosen one configuration as reference. The transfer time of this reference configuration was 29.6 years and the fastest one, which is technically more challenging, still required 28.3 years. As all flight times of this parameter study were longer than 25 years, we further shortened the transfer time by applying a launcher-provided hyperbolic excess energy up to 49 km2/s2. The resulting minimal flight time for the reference configuration was then 27.8 years. The following, more precise optimization to a launch with the European Ariane 5 ECA rocket reduced the transfer time to 27.5 years. This is the fastest mission design of our study that is flexible enough to allow a launch every year. The inclusion of a fly-by at Jupiter finally resulted in a flight time of 23.8 years,which is below the set transfer-time limit. However, compared to the 27.5-year transfer,this mission design has a significantly reduced launch window and mission flexibility if the escape direction is restricted to the heliosphere’s “nose". KW - low-thrust trajectory optimization KW - heliosphere KW - ion propulsion Y1 - 2011 N1 - IEPC-2011-051 32nd International Electric Propulsion Conference,September 11–15, 2011 Wiesbaden, Germany SP - 1 EP - 12 ER - TY - JOUR A1 - Scholz, Christina A1 - Romagnoli, Daniele A1 - Dachwald, Bernd A1 - Theil, Stephan T1 - Performance analysis of an attitude control system for solar sails using sliding masses JF - Advances in Space Research Y1 - 2011 SN - 0273-1177 VL - 48 IS - 11 SP - 1822 EP - 1835 PB - Elsevier CY - Amsterdam ER - TY - CHAP A1 - Loeb, Horst W. A1 - Schartner, Karl-Heinz A1 - Dachwald, Bernd A1 - Ohndorf, Andreas A1 - Seboldt, Wolfgang T1 - An Interstellar – Heliopause mission using a combination of solar/radioisotope electric propulsion T2 - Presented at the 32nd International Electric Propulsion Conference N2 - There is common agreement within the scientific community that in order to understand our local galactic environment it will be necessary to send a spacecraft into the region beyond the solar wind termination shock. Considering distances of 200 AU for a new mission, one needs a spacecraft travelling at a speed of close to 10 AU/yr in order to keep the mission duration in the range of less than 25 yrs, a transfer time postulated by ESA.Two propulsion options for the mission have been proposed and discussed so far: the solar sail propulsion and the ballistic/radioisotope electric propulsion. As a further alternative, we here investigate a combination of solar-electric propulsion and radioisotope-electric propulsion. The solar-electric propulsion stage consists of six 22 cm diameter “RIT-22”ion thrusters working with a high specific impulse of 7377 s corresponding to a positive grid voltage of 5 kV. Solar power of 53 kW BOM is provided by a light-weight solar array. The REP-stage consists of four space-proven 10 cm diameter “RIT-10” ion thrusters that will be operating one after the other for 9 yrs in total. Four advanced radioisotope generators provide 648 W at BOM. The scientific instrument package is oriented at earlier studies. For its mass and electric power requirement 35 kg and 35 W are assessed, respectively. Optimized trajectory calculations, treated in a separate contribution, are based on our “InTrance” method.The program yields a burn out of the REP stage in a distance of 79.6 AU for a usage of 154 kg of Xe propellant. With a C3 = 45,1 (km/s)2 a heliocentric probe velocity of 10 AU/yr is reached at this distance, provided a close Jupiter gravity assist adds a velocity increment of 2.7 AU/yr. A transfer time of 23.8 yrs results for this scenario requiring about 450 kg Xe for the SEP stage, jettisoned at 3 AU. We interpret the SEP/REP propulsion as a competing alternative to solar sail and ballistic/REP propulsion. Omiting a Jupiter fly-by even allows more launch flexibility, leaving the mission duration in the range of the ESA specification. Y1 - 2011 N1 - 32nd International Electric Propulsion Conference, 11-15 September. Wiesbaden, Germany SP - 1 EP - 7 ER - TY - JOUR A1 - Karamanidis, Kiros A1 - Albracht, Kirsten A1 - Braunstein, Bjoern A1 - Catala, Maria Moreno A1 - Goldmann, Jan-Peter A1 - Brüggemann, Gert-Peter T1 - Lower leg musculoskeletal geometry and sprint performance JF - Gait and Posture N2 - 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. Y1 - 2011 U6 - https://doi.org/10.1016/j.gaitpost.2011.03.009 SN - 0966-6362 VL - 34 IS - 1 SP - 138 EP - 141 PB - Elsevier CY - Amsterdam ER - TY - THES A1 - Behbahani, Mehdi T1 - Modeling and Simulation of Shear-Dependent Platelet Reactions in Blood Vessels and Blood-Contacting Medical Devices Y1 - 2011 SN - 978-3-8439-0134-5 PB - Verlag Dr. Hut CY - München ER - TY - CHAP A1 - Dachwald, Bernd A1 - Xu, Changsheng A1 - Feldmann, Marco A1 - Plescher, Engelbert T1 - IceMole : Development of a novel subsurface ice probe and testing of the first prototype on the Morteratsch Glacier T2 - EGU General Assembly 2011 Vienna | Austria | 03 – 08 April 2011 N2 - We present the novel concept of a combined drilling and melting probe for subsurface ice research. This probe, named “IceMole”, is currently developed, built, and tested at the FH Aachen University of Applied Sciences’ Astronautical Laboratory. Here, we describe its first prototype design and report the results of its field tests on the Swiss Morteratsch glacier. Although the IceMole design is currently adapted to terrestrial glaciers and ice shields, it may later be modified for the subsurface in-situ investigation of extraterrestrial ice, e.g., on Mars, Europa, and Enceladus. If life exists on those bodies, it may be present in the ice (as life can also be found in the deep ice of Earth). Y1 - 2011 ER - TY - JOUR A1 - Digel, Ilya T1 - Primary thermosensory events in cells JF - Transient receptor potential channels / Md. Shahidul Islam, ed. Y1 - 2011 SN - 978-94-007-0264-6 N1 - (Advances in experimental medicine and biology ; 704) SP - 451 EP - 468 PB - Springer CY - Dordrecht [u.a.] ER - TY - JOUR A1 - Kurulgan Demirci, Eylem A1 - Demirci, T. A1 - Trzewik, Jürgen A1 - Linder, Peter A1 - Karakulah, G. A1 - Artmann, Gerhard A1 - Sakizli, M. A1 - Temiz Artmann, Aysegül T1 - Genome-Wide Gene Expression Analysis of NIH 3T3 Cell Line Under Mechanical Stimulation JF - Cellular and molecular bioengineering. 4 (2011), H. 1 Y1 - 2011 SN - 1865-5025 SP - 46 EP - 55 PB - Springer CY - Berlin ER - TY - JOUR A1 - Dachwald, Bernd A1 - Wurm, Patrick T1 - Mission analysis and performance comparison for an Advanced Solar Photon Thruster JF - Advances in Space Research Y1 - 2011 SN - 0273-1177 VL - 48 IS - 11 SP - 1858 EP - 1868 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Digel, Ilya A1 - Temiz Artmann, Aysegül T1 - The emperor's new body : seeking for a blueprint of limb regeneration in humans JF - Stem cell engineering : principles and applications / Gerhard M. Artmann ... eds. Y1 - 2011 SN - 978-3-642-11864-7 SP - 3 EP - 37 PB - Springer CY - Berlin [u.a.] ER - TY - JOUR A1 - Behbahani, Mehdi A1 - Probst, M. A1 - Mai, A. A1 - Tran, L. A1 - Vonderstein, K. A1 - Keschenau, P. A1 - Linde, T. A1 - Steinseifer, U. A1 - Behr, M. A1 - Mottaghy, K. T1 - The influence of high shear on thrombosis and hemolysis in artificial organs JF - Artificial Organs Y1 - 2010 SN - 0391-3988 N1 - Special Issue: SI ; Meeting abstract VL - 33 IS - 7 SP - 426 EP - 426 ER - TY - JOUR A1 - Jansen, Sebastian A1 - Behbahani, Mehdi A1 - Laumen, Marco A1 - Kaufmann, Tim A1 - Hormes, Marcus A1 - Schmitz-Rode, Thomas A1 - Behr, Marek A1 - Steinseifer, Ulrich T1 - 3D Stereo-PIV Validation for CFD-Simulation of Steady Flow through the Human Aorta using Rapid-Prototyping techniques Y1 - 2010 N1 - abstract ; IV International Symposium on Modelling of Physiological Flows, Sardinia, Italy, June 02-05, 2010 ; MPF2010 ER - TY - JOUR A1 - Behbahani, Mehdi A1 - Nam, J. A1 - Waluga, C. A1 - Behr, M. A1 - Pasquali, M. A1 - Mottaghy, K. T1 - Modeling and Numerical Analysis of Platelet Activation, Adhesion and Aggregation in Artificial Organs Y1 - 2010 U6 - https://doi.org/10.1097/01.mat.0000369377.65122.a3 N1 - Posterpresentation American Society of Artificial Organs (ASAIO), Baltimore, USA, May 27-29, 2010 ER - TY - JOUR A1 - Jansen, S. V. A1 - Behbahani, Mehdi A1 - Laumen, M. A1 - Kaufmann, T. A1 - Hormes, M. A1 - Behr, M. A1 - Schmitz-Rode, T. A1 - Steinseifer, U. T1 - Investigation of Steady Flow Through a Realistic Model of the Thoracic Human Aorta Using 3D Stereo PIV and CFD-Simulation Y1 - 2010 N1 - Posterpresentation ; American Society of Artificial Organs (ASAIO), Baltimore, USA, May 27-29, 2010 ER - TY - JOUR A1 - Nam, J. A1 - Arora, D. A1 - Behbahani, Mehdi A1 - Probst, M. A1 - Benkowski, R. A1 - Behr, M. A1 - Pasquali, M. T1 - New computational method in hemolysis analysis for artificial heart pump Y1 - 2010 N1 - Posterpresentation ; American Society of Artificial Organs (ASAIO), Baltimore, USA, May 27-29, 2010 ER - TY - JOUR A1 - Behbahani, Mehdi A1 - Probst, M. A1 - Mai, A. A1 - Behr, M. A1 - Tran, L. A1 - Vonderstein, K. A1 - Mottaghy, K. T1 - Numerical Prediction of Blood Damage in Biomedical Devices Y1 - 2010 N1 - Posterpresentation ; Biomedica Congress, Aachen, March 17-18, 2010 ER - TY - JOUR A1 - Probst, M. A1 - Behbahani, Mehdi A1 - Borrmann, E. A1 - Elgeti, S. A1 - Nicolai, M. A1 - Behr, M. T1 - Hemodynamic Modeling for Numerical Analysis and Design of Medical Devices Y1 - 2010 N1 - Posterpresentation ; NIC Symposium 2010 ; 24 - 25 February 2010 Jülich, Germany ER - TY - JOUR A1 - Behbahani, Mehdi A1 - Mai, A. A1 - Bergmann, B. A1 - Waluga, C. A1 - Behr, M. A1 - Tran, L. A1 - Vonderstein, K. A1 - Mottaghy, K. T1 - Modeling and Numerical Simulation of Blood Damage Y1 - 2010 N1 - Posterpresentation ; Umbrella Symposium "Modelling and Simulation in Medicine, Engineering and Sciences", Forschungszentrum Jülich, January 18-20, 2010 ER - TY - JOUR A1 - Behbahani, Mehdi A1 - Mai, A. A1 - Waluga, C. A1 - Bergmann, B. A1 - Tran, L. A1 - Vonderstein, K. A1 - Behr, M. A1 - Mottaghy, K. T1 - Numerical Modeling of Flow-Related Thrombus Formation under Physiological and Non-Physiological Flow Conditions JF - Acta Physiologica Y1 - 2010 SN - 1748-1716 N1 - Joint Congress of the Scandinavian and German Physiological Societies, Copenhagen, Denmark, March 27-30, 2010 VL - 198 IS - Supplement 677 SP - 185 ER - TY - JOUR A1 - Kotliar, Konstantin A1 - Nagel, Edgar A1 - Vilser, Walthard A1 - Seidova, Seid-Fatima A1 - Lanzl, Ines T1 - Microstructural alterations of retinal arterial blood column along the vessel axis in systemic hypertension JF - Investigative Ophthalmology & Visual Science, IOVS N2 - Purpose: Image analysis by the retinal vessel analyzer (RVA) observes retinal vessels in their dynamic state online noninvasively along a chosen vessel segment. It has been found that high-frequency diameter changes in the retinal artery blood column along the vessel increase significantly in anamnestically healthy volunteers with increasing age and in patients with glaucoma during vascular dilation. This study was undertaken to investigate whether longitudinal sections of the retinal artery blood column are altered in systemic hypertension. Methods: Retinal arteries of 15 untreated patients with essential arterial hypertension (age, 50.9 ± 11.9 years) and of 15 age-matched anamnestically healthy volunteers were examined by RVA. After baseline assessment, a monochromatic luminance flicker (530–600 nm; 12.5 Hz; 20 s) was applied to evoke retinal vasodilation. Differences in amplitude and frequency of spatial artery blood column diameter change along segments (longitudinal arterial profiles) of 1 mm in length were measured and analyzed using Fourier transformation. Results: In the control group, average reduced power spectra (ARPS) of longitudinal arterial profiles did not differ when arteries changed from constriction to dilation. In the systemic hypertension group, ARPS during constriction, baseline, and restoration were identical and differed from ARPS during dilation (P < 0.05). Longitudinal arterial profiles in both groups showed significant dissimilitude at baseline and restoration (P < 0.05). Conclusions: The retinal artery blood column demonstrates microstructural alterations in systemic hypertension and is less irregular along the vessel axis during vessel dilation. These microstructural changes may be an indication of alterations in vessel wall rigidity, vascular endothelial function, and smooth muscle cells in this disease, leading to impaired perfusion and regulation. Y1 - 2010 U6 - https://doi.org/10.1167/iovs.09-3649 SN - 0146-0404 VL - 51 IS - 4 SP - 2165 EP - 2172 PB - ARVO CY - Rockville, Md. ER - TY - JOUR A1 - Pressler, Axel A1 - Esefeld, Katrin A1 - Scherr, Johannes A1 - Ali, Mohammad A1 - Hanssen, Henner A1 - Kotliar, Konstantin A1 - Lanzl, Ines A1 - Halle, Martin A1 - Kaemmerer, Harald A1 - Schmidt-Trucksäss, Arno A1 - Hager, Alfred T1 - Structural alterations of retinal arterioles in adults late after repair of aortic isthmic coarctation JF - The American Journal of Cardiology N2 - Patients after coarctation repair still have an increased risk of cardiovascular or cerebrovascular events. This has been explained by the persisting hypertension and alterations in the peripheral vessels. However, involvement of the central vessels such as the retinal arteries is virtually unknown. A total of 34 patients after coarctation repair (22 men and 12 women; 23 to 58 years old, age range 0 to 32 years at surgical repair) and 34 nonhypertensive controls underwent structural and functional retinal vessel analysis. Using structural analysis, the vessel diameters were measured. Using functional analysis, the endothelium-dependent vessel dilation in response to flicker light stimulation was assessed. In the patients after coarctation repair, the retinal arteriolar diameter was significantly reduced compared to that of the controls (median 182 μm, first to third quartile 171 to 197; vs 197 μm, first to third quartile 193 to 206; p <0.001). These findings were independent of the peripheral blood pressure and age at intervention. No differences were found for venules. The functional analysis findings were not different between the patients and controls (maximum dilation 3.5%, first to third quartile 2.1% to 4.5% vs 3.6%, first to third quartile 2.2% to 4.3%; p = 0.81), indicating preserved autoregulative mechanisms. In conclusion, the retinal artery diameter is reduced in patients after coarctation repair, independent of their current blood pressure level and age at intervention. As a structural marker of chronic vessel damage associated with past, current, or future hypertension, retinal arteriolar narrowing has been linked to stroke incidence. These results indicate an involvement of cerebral microcirculation in aortic coarctation, despite timely repair, and might contribute to explain the increased rate of cerebrovascular events in such patients. Y1 - 2010 U6 - https://doi.org/10.1016/j.amjcard.2009.10.070 SN - 0002-9149 VL - 105 IS - 5 SP - 740 EP - 744 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Garhofer, Gerhard A1 - Bek, Toke A1 - Boehm, Andreas G. A1 - Gherghel, Doina A1 - Grundwald, Juan A1 - Jeppesen, Peter A1 - Kergoat, Hélène A1 - Kotliar, Konstantin A1 - Lanzl, Ines A1 - Lovasik, John V. A1 - Nagel, Edgar A1 - Vilser, Walthard A1 - Orgul, Selim A1 - Schmetterer, Leopold T1 - Use of the retinal vessel analyzer in ocular blood flow research JF - Acta Ophthalmol N2 - The present article describes a standard instrument for the continuous online determination of retinal vessel diameters, the commercially available retinal vessel analyzer. This report is intended to provide informed guidelines for measuring ocular blood flow with this system. The report describes the principles underlying the method and the instruments currently available, and discusses clinical protocol and the specific parameters measured by the system. Unresolved questions and the possible limitations of the technique are also discussed. Y1 - 2010 U6 - https://doi.org/10.1111/j.1755-3768.2009.01587.x SN - 1755-3768 VL - 88 IS - 7 SP - 717 EP - 722 PB - Wiley-Blackwell CY - Oxford ER - TY - JOUR A1 - Kozhalakova, A. A. A1 - Zhubanova, Azhar A. A1 - Mansurov, Z. A. A1 - Digel, Ilya A1 - Tazhibayeva, S. M. A1 - Artmann, Gerhard A1 - Temiz Artmann, Aysegül T1 - Adsorption of bacterial lipopolysaccharides on carbonized rice shell JF - Science of Central Asia (2010) Y1 - 2010 SP - 50 EP - 54 ER - TY - JOUR A1 - Kurz, R. A1 - Linder, Peter A1 - Trzewik, Jürgen A1 - Rüffer, M. A1 - Artmann, Gerhard A1 - Digel, Ilya A1 - Rothermel, A. A1 - Robitzki, A. A1 - Temiz Artmann, Aysegül T1 - Contractile tension and beating rates of self-exciting monolayers and 3D-tissue constructs of neonatal rat cardiomyocytes JF - Medical and Biological Engineering and Computing N2 - The CellDrum technology (The term 'CellDrum technology' includes a couple of slightly different technological setups for measuring lateral mechanical tension in various types of cell monolayers or 3D-tissue constructs) was designed to quantify the contraction rate and mechanical tension of self-exciting cardiac myocytes. Cells were grown either within flexible, circular collagen gels or as monolayer on top of respective 1-mum thin silicone membranes. Membrane and cells were bulged outwards by air pressure. This biaxial strain distribution is rather similar the beating, blood-filled heart. The setup allowed presetting the mechanical residual stress level externally by adjusting the centre deflection, thus, mimicking hypertension in vitro. Tension was measured as oscillating differential pressure change between chamber and environment. A 0.5-mm thick collagen-cardiac myocyte tissue construct induced after 2 days of culturing (initial cell density 2 x 10(4) cells/ml), a mechanical tension of 1.62 +/- 0.17 microN/mm(2). Mechanical load is an important growth regulator in the developing heart, and the orientation and alignment of cardiomyocytes is stress sensitive. Therefore, it was necessary to develop the CellDrum technology with its biaxial stress-strain distribution and defined mechanical boundary conditions. Cells were exposed to strain in two directions, radially and circumferentially, which is similar to biaxial loading in real heart tissues. Thus, from a biomechanical point of view, the system is preferable to previous setups based on uniaxial stretching. Y1 - 2010 U6 - https://doi.org/10.1007/s11517-009-0552-y SN - 1741-0444 VL - 48 IS - 1 SP - 59 EP - 65 PB - Springer Nature CY - Cham ER - TY - JOUR A1 - Pham, Phu Tinh A1 - Vu, Khoi Duc A1 - Tran, Thanh Ngoc A1 - Staat, Manfred T1 - A primal-dual algorithm for shakedown analysis of elastic-plastic bounded linearly kinematic hardening bodies Y1 - 2010 N1 - ECCM 2010, IV European Conference on Computational Mechanics, Paris, France, May 16-21, 2010. SP - 1 EP - 7 ER - TY - JOUR A1 - Nguyen, N.-H. A1 - Raatschen, Hans-Jürgen A1 - Staat, Manfred T1 - A hyperelastic model of biological tissue materials in tubular organs Y1 - 2010 N1 - ECCM 2010, IV European Conference on Computational Mechanics, Paris, France, May 16-21, 2010. SP - 1 EP - 12 ER - TY - CHAP A1 - Borggräfe, Andreas A1 - Dachwald, Bernd T1 - Mission performance evaluation for solar sails using a refined SRP force model with variable optical coefficients T2 - 2nd International Symposium on Solar Sailing N2 - Solar sails provide ignificant advantages over other low-thrust propulsion systems because they produce thrust by the momentum exchange from solar radiation pressure (SRP) and thus do not consume any propellant.The force exerted on a very thin sail foil basically depends on the light incidence angle. Several analytical SRP force models that describe the SRP force acting on the sail have been established since the 1970s. All the widely used models use constant optical force coefficients of the reflecting sail material. In 2006,MENGALI et al. proposed a refined SRP force model that takes into account the dependancy of the force coefficients on the light incident angle,the sail’s distance from the sun (and thus the sail emperature) and the surface roughness of the sail material [1]. In this paper, the refined SRP force model is compared to the previous ones in order to identify the potential impact of the new model on the predicted capabilities of solar sails in performing low-cost interplanetary space missions. All force models have been implemented within InTrance, a global low-thrust trajectory optimization software utilizing evolutionary neurocontrol [2]. Two interplanetary rendezvous missions, to Mercury and the near-Earth asteroid 1996FG3, are investigated. Two solar sail performances in terms of characteristic acceleration are examined for both scenarios, 0.2 mm/s2 and 0.5 mm/s2, termed “low” and “medium” sail performance. In case of the refined SRP model, three different values of surface roughness are chosen, h = 0 nm, 10 nm and 25 nm. The results show that the refined SRP force model yields shorter transfer times than the standard model. Y1 - 2010 N1 - 2nd International Symposium on Solar Sailing, ISSS 2010, 2010-07-20 - 2010-07-22. New York City College of Technology of the City University of New York, USA SP - 1 EP - 6 ER -