TY - CHAP A1 - Bhattarai, Aroj A1 - Staat, Manfred ED - Fernandes, P.R. ED - Tavares, J. M. T1 - Pectopexy to repair vaginal vault prolapse: a finite element approach T2 - Proceedings CMBBE 2018 N2 - The vaginal prolapse after hysterectomy (removal of the uterus) is often associated with the prolapse of the vaginal vault, rectum, bladder, urethra or small bowel. Minimally invasive surgery such as laparoscopic sacrocolpopexy and pectopexy are widely performed for the treatment of the vaginal prolapse with weakly supported vaginal vault after hysterectomy using prosthetic mesh implants to support (or strengthen) lax apical ligaments. Implants of different shape, size and polymers are selected depending on the patient’s anatomy and the surgeon’s preference. In this computational study on pectopexy, DynaMesh®-PRP soft, GYNECARE GYNEMESH® PS Nonabsorbable PROLENE® soft and Ultrapro® are tested in a 3D finite element model of the female pelvic floor. The mesh model is implanted into the extraperitoneal space and sutured to the vaginal stump with a bilateral fixation to the iliopectineal ligament at both sides. Numerical simulations are conducted at rest, after surgery and during Valsalva maneuver with weakened tissues modeled by reduced tissue stiffness. Tissues and prosthetic meshes are modeled as incompressible, isotropic hyperelastic materials. The positions of the organs are calculated with respect to the pubococcygeal line (PCL) for female pelvic floor at rest, after repair and during Valsalva maneuver using the three meshes. Y1 - 2018 N1 - 15th International Symposium on Computer Methods in Biomechanics and Biomedical Engineering and 3rd Conference on Imaging and Visualization. CMBBE 2018. 26-29 March 2018, Lisbon, Portugal ER - TY - JOUR A1 - Bhattarai, Aroj A1 - Staat, Manfred T1 - Modelling of Soft Connective Tissues to Investigate Female Pelvic Floor Dysfunctions JF - Computational and Mathematical Methods in Medicine N2 - After menopause, decreased levels of estrogen and progesterone remodel the collagen of the soft tissues thereby reducing their stiffness. Stress urinary incontinence is associated with involuntary urine leakage due to pathological movement of the pelvic organs resulting from lax suspension system, fasciae, and ligaments. This study compares the changes in the orientation and position of the female pelvic organs due to weakened fasciae, ligaments, and their combined laxity. A mixture theory weighted by respective volume fraction of elastin-collagen fibre compound (5%), adipose tissue (85%), and smooth muscle (5%) is adopted to characterize the mechanical behaviour of the fascia. The load carrying response (other than the functional response to the pelvic organs) of each fascia component, pelvic organs, muscles, and ligaments are assumed to be isotropic, hyperelastic, and incompressible. Finite element simulations are conducted during Valsalva manoeuvre with weakened tissues modelled by reduced tissue stiffness. A significant dislocation of the urethrovesical junction is observed due to weakness of the fascia (13.89 mm) compared to the ligaments (5.47 mm). The dynamics of the pelvic floor observed in this study during Valsalva manoeuvre is associated with urethral-bladder hypermobility, greater levator plate angulation, and positive Q-tip test which are observed in incontinent females. Y1 - 2018 U6 - https://doi.org/10.1155/2018/9518076 SN - 1748-6718 VL - 2018 IS - Article ID 9518076 SP - 1 EP - 16 PB - Hindawi CY - New York, NY ER - TY - CHAP A1 - Digel, Ilya A1 - Akimbekov, Nuraly S. A1 - Kistaubayeva, Aida A1 - Zhubanova, Azhar A. ED - Artmann, Gerhard ED - Temiz Artmann, Aysegül ED - Zhubanova, Azhar A. ED - Digel, Ilya T1 - Microbial Sampling from Dry Surfaces: Current Challenges and Solutions T2 - Biological, Physical and Technical Basics of Cell Engineering N2 - Sampling of dry surfaces for microorganisms is a main component of microbiological safety and is of critical importance in many fields including epidemiology, astrobiology as well as numerous branches of medical and food manufacturing. Aspects of biofilm formation, analysis and removal in aqueous solutions have been thoroughly discussed in literature. In contrast, microbial communities on air-exposed (dry) surfaces have received significantly less attention. Diverse surface sampling methods have been developed in order to address various surfaces and microbial groups, but they notoriously show poor repeatability, low recovery rates and suffer from lack of mutual consistency. Quantitative sampling for viable microorganisms represents a particular challenge, especially on porous and irregular surfaces. Therefore, it is essential to examine in depth the factors involved in microorganisms’ recovery efficiency and accuracy depending on the sampling technique used. Microbial colonization, retention and community composition on different dry surfaces are very complex and rely on numerous physicochemical and biological factors. This study is devoted to analyze and review the (a) physical phenomena and intermolecular forces relevant for microbiological surface sampling; (b) challenges and problems faced by existing sampling methods for viable microorganisms and (c) current directions of engineering and research aimed at improvement of quality and efficiency of microbiological surface sampling. KW - Sampling methods KW - Surface microorganisms KW - Dry surfaces KW - Microbial adhesion KW - Swabbing Y1 - 2018 SN - 978-981-10-7904-7 U6 - https://doi.org/10.1007/978-981-10-7904-7_19 SP - 421 EP - 456 PB - Springer CY - Singapore ER - TY - CHAP A1 - Jean-Pierre P., de Vera A1 - Baque, Mickael A1 - Billi, Daniela A1 - Böttger, Ute A1 - Bulat, Sergey A1 - Czupalla, Markus A1 - Dachwald, Bernd A1 - de la Torre, Rosa A1 - Elsaesser, Andreas A1 - Foucher, Frédéric A1 - Korsitzky, Hartmut A1 - Kozyrovska, Natalia A1 - Läufer, Andreas A1 - Moeller, Ralf A1 - Olsson-Francis, Karen A1 - Onofri, Silvano A1 - Sommer, Stefan A1 - Wagner, Dirk A1 - Westall, Frances T1 - The search for life on Mars and in the Solar System - strategies, logistics and infrastructures T2 - 69th International Astronautical Congress (IAC) N2 - The question "Are we alone in the Universe?" is perhaps the most fundamental one that affects mankind. How can we address the search for life in our Solar System? Mars, Enceladus and Europa are the focus of the search for life outside the terrestrial biosphere. While it is more likely to find remnants of life (fossils of extinct life) on Mars because of its past short time window of the surface habitability, it is probably more likely to find traces of extant life on the icy moons and ocean worlds of Jupiter and Saturn. Nevertheless, even on Mars there could still be a chance to find extant life in niches near to the surface or in just discovered subglacial lakes beneath the South Pole ice cap. Here, the different approaches for the detection of traces of life in the form of biosignatures including pre-biotic molecules will be presented. We will outline the required infrastructure for this enterprise and give examples of future mission concepts to investigate the presence of life on other planets and moons. Finally, we will provide suggestions on methods, techniques, operations and strategies for preparation and realization of future life detection missions. KW - life detection KW - Mars KW - icy moons KW - habitability KW - space missions Y1 - 2018 N1 - 69th International Astronautical Congress (IAC), Bremen, Germany, 1-5 October 2018. SP - 1 EP - 8 ER - TY - JOUR A1 - Digel, Ilya A1 - Wehlitz, V. A1 - Kayser, Peter A1 - Figiel-Lange, A. A1 - Bassam, R. A1 - Rundstedt, F. von T1 - Suspension depletion approach for exemption of infected Solanum jasminoides cells from pospiviroids JF - Plant Pathology N2 - Despite numerous studies, viroid elimination from infected plants remains a very challenging task. This study introduces for the first time a novel ‘suspension depletion’ approach for exemption of Solanum jasminoides plants from viroids. The proposed method implies initial establishment of suspension cultures of the infected plant cells. The suspended cells were then physically treated (mild thermotherapy, 33 °C), which presumably delayed the replication of the viroid. The viroid concentration in the treated biomass was monitored weekly using pospiviroid-specific PCR. After 10–12 weeks of continuous treatment, a sufficient decrease in viroid concentration was observed such that the infection became undetectable by PCR. The treated single cells then gave rise to microcolonies on a solid culture medium and the obtained viroid-negative clones were further promoted to regenerate into viroid-free plants. Three years of accumulated experimental data suggests feasibility, broad applicability, and good efficacy of the proposed approach. Y1 - 2018 U6 - https://doi.org/10.1111/ppa.12750 SN - 1365-3059 VL - 67 IS - 2 SP - 358 EP - 365 PB - Wiley CY - Oxford ER - TY - JOUR A1 - Conzen, Catharina A1 - Albanna, Walid A1 - Weiss, Miriam A1 - Kürten, David A1 - Vilser, Walthard A1 - Kotliar, Konstantin A1 - Zäske, Charlotte A1 - Clusmann, Hans A1 - Schubert, Gerrit Alexander T1 - Vasoconstriction and Impairment of Neurovascular Coupling after Subarachnoid Hemorrhage: a Descriptive Analysis of Retinal Changes JF - Translational Stroke Research N2 - Impaired cerebral autoregulation and neurovascular coupling (NVC) contribute to delayed cerebral ischemia after subarachnoid hemorrhage (SAH). Retinal vessel analysis (RVA) allows non-invasive assessment of vessel dimension and NVC hereby demonstrating a predictive value in the context of various neurovascular diseases. Using RVA as a translational approach, we aimed to assess the retinal vessels in patients with SAH. RVA was performed prospectively in 24 patients with acute SAH (group A: day 5–14), in 11 patients 3 months after ictus (group B: day 90 ± 35), and in 35 age-matched healthy controls (group C). Data was acquired using a Retinal Vessel Analyzer (Imedos Systems UG, Jena) for examination of retinal vessel dimension and NVC using flicker-light excitation. Diameter of retinal vessels—central retinal arteriolar and venular equivalent—was significantly reduced in the acute phase (p < 0.001) with gradual improvement in group B (p < 0.05). Arterial NVC of group A was significantly impaired with diminished dilatation (p < 0.001) and reduced area under the curve (p < 0.01) when compared to group C. Group B showed persistent prolonged latency of arterial dilation (p < 0.05). Venous NVC was significantly delayed after SAH compared to group C (A p < 0.001; B p < 0.05). To our knowledge, this is the first clinical study to document retinal vasoconstriction and impairment of NVC in patients with SAH. Using non-invasive RVA as a translational approach, characteristic patterns of compromise were detected for the arterial and venous compartment of the neurovascular unit in a time-dependent fashion. Recruitment will continue to facilitate a correlation analysis with clinical course and outcome. Y1 - 2018 U6 - https://doi.org/10.1007/s12975-017-0585-8 SN - 1868-601X IS - 9 SP - 284 EP - 293 PB - Springer Nature CY - Cham ER - TY - JOUR A1 - Heinke, Lars N. A1 - Knicker, Axel J. A1 - Albracht, Kirsten T1 - Evaluation of passively induced shoulder stretch reflex using an isokinetic dynamometer in male overhead athletes JF - Isokinetics and Exercise Science N2 - BACKGROUND: Muscle stretch reflexes are widely considered to beneficially influence joint stability and power generation in the lower limbs. While in the upper limbs and especially in the muscles surrounding the shoulder joint such evidence is lacking. OBJECTIVE: To quantify the electromyographical response in the muscles crossing the shoulder of specifically trained overhead athletes to an anterior perturbation force. METHODS: Twenty healthy male participants performed six sets of different external shoulder rotation stretches on an isokinetic dynamometer over a range of amplitudes and muscle pre-activation moment levels. All stretches were applied with a dynamometer acceleration of 10,000∘/s2 and a velocity of 150∘/s. Electromyographical response was measured via sEMG. RESULTS: Consistent reflexes were not observed in all experimental conditions. The reflex latencies revealed a significant muscle main effect (F (2,228) = 99.31, p< 0.001; η2= 0.466; f= 0.934) and a pre-activation main effect (F (1,228) = 142.21, p< 0.001; η2= 0.384; f= 1.418). The stretch reflex amplitude yielded a significant pre-activation main effect (F (1,222) = 470.373, p< 0.001; η2= 0.679; f= 1.454). CONCLUSION: Short latency muscle reflexes showed a tendency to an anterior to posterior muscle recruitment whereby the main internal rotator muscles of the shoulder revealed the most consistent results. Y1 - 2018 U6 - https://doi.org/10.3233/IES-184111 SN - 1878-5913 VL - 26 IS - 4 SP - 265 EP - 274 PB - IOS Press CY - Amsterdam ER - TY - JOUR A1 - Lapitan, Denis G. A1 - Rogatkin, Dmitrii A. A1 - Persheyev, Sydulla K. A1 - Kotliar, Konstantin T1 - False spectra formation in the differential two-channel scheme of the laser Doppler flowmeter JF - Biomedizinische Technik N2 - Noise in the differential two-channel scheme of a classic laser Doppler flowmetry (LDF) instrument was studied. Formation of false spectral components in the output signal due to beating of electrical signals in the differential amplifier was found out. The improved block-diagram of the flowmeter was developed allowing to reduce the noise. Y1 - 2018 U6 - https://doi.org/10.1515/bmt-2017-0060 SN - 0013-5585 VL - 63 IS - 4 SP - 439 EP - 444 PB - De Gruyter CY - Berlin ER - TY - JOUR A1 - Albanna, Walid A1 - Kotliar, Konstantin A1 - Lüke, Jan Niklas A1 - Alpdogan, Serdar A1 - Conzen, Catharina A1 - Lindauer, Ute A1 - Clusmann, Hans A1 - Hescheler, Jürgen A1 - Vilser, Walthard A1 - Schneider, Toni A1 - Schubert, Gerrit Alexander T1 - Non-invasive evaluation of neurovascular coupling in the murine retina by dynamic retinal vessel analysis JF - Plos one N2 - Background Impairment of neurovascular coupling (NVC) was recently reported in the context of subarachnoid hemorrhage and may correlate with disease severity and outcome. However, previous techniques to evaluate NVC required invasive procedures. Retinal vessels may represent an alternative option for non-invasive assessment of NVC. Methods A prototype of an adapted retinal vessel analyzer was used to assess retinal vessel diameter in mice. Dynamic vessel analysis (DVA) included an application of monochromatic flicker light impulses in predefined frequencies for evaluating NVC. All retinae were harvested after DVA and electroretinograms were performed. Results A total of 104 retinal scans were conducted in 21 male mice (90 scans). Quantitative arterial recordings were feasible only in a minority of animals, showing an emphasized reaction to flicker light impulses (8 mice; 14 scans). A characteristic venous response to flicker light, however, could observed in the majority of animals. Repeated measurements resulted in a significant decrease of baseline venous diameter (7 mice; 7 scans, p < 0.05). Ex-vivo electroretinograms, performed after in-vivo DVA, demonstrated a significant reduction of transretinal signaling in animals with repeated DVA (n = 6, p < 0.001). Conclusions To the best of our knowledge, this is the first non-invasive study assessing murine retinal vessel response to flicker light with characteristic changes in NVC. The imaging system can be used for basic research and enables the investigation of retinal vessel dimension and function in control mice and genetically modified animals. Y1 - 2018 U6 - https://doi.org/10.1371/journal.pone.0204689 VL - 13 IS - 10 PB - PLOS CY - San Francisco ER - TY - JOUR A1 - Balakirski, Galina A1 - Kotliar, Konstantin A1 - Pauly, Karolin J. A1 - Krings, Laura K. A1 - Rübben, Albert A1 - Baron, Jens M. A1 - Schmitt, Laurenz T1 - Surgical Site Infections After Dermatologic Surgery in Immunocompromised Patients: A Single-Center Experience JF - Dermatologic Surgery N2 - BACKGROUND Immunosuppression is often considered as an indication for antibiotic prophylaxis to prevent surgical site infections (SSI) while performing skin surgery. However, the data on the risk of developing SSI after dermatologic surgery in immunosuppressed patients are limited. PATIENTS AND METHODS All patients of the Department of Dermatology and Allergology at the University Hospital of RWTH Aachen in Aachen, Germany, who underwent hospitalization for a dermatologic surgery between June 2016 and January 2017 (6 months), were followed up after surgery until completion of the wound healing process. The follow-up addressed the occurrence of SSI and the need for systemic antibiotics after the operative procedure. Immunocompromised patients were compared with immunocompetent patients. The investigation was conducted as a retrospective analysis of patient records. RESULTS The authors performed 284 dermatologic surgeries in 177 patients. Nineteen percent (54/284) of the skin surgery was performed on immunocompromised patients. The most common indications for surgical treatment were nonmelanoma skin cancer and malignant melanomas. Surgical site infections occurred in 6.7% (19/284) of the cases. In 95% (18/19), systemic antibiotic treatment was needed. Twenty-one percent of all SSI (4/19) were seen in immunosuppressed patients. CONCLUSION According to the authors' data, immunosuppression does not represent a significant risk factor for SSI after dermatologic surgery. However, larger prospective studies are needed to make specific recommendations on the use of antibiotic prophylaxis while performing skin surgery in these patients. The available data on complications after dermatologic surgery have improved over the past years. Particularly, additional risk factors have been identified for surgical site infections (SSI). Purulent surgical sites, older age, involvement of head, neck, and acral regions, and also the involvement of less experienced surgeons have been reported to increase the risk of the SSI after dermatologic surgeries.1 In general, the incidence of SSI after skin surgery is considered to be low.1,2 However, antibiotics in dermatologic surgeries, especially in the perioperative setting, seem to be overused,3,4 particularly regarding developing antibiotic resistances and side effects. Immunosuppression has been recommended to be taken into consideration as an additional indication for antibiotic prophylaxis to prevent SSI after skin surgery in special cases.5,6 However, these recommendations do not specify the exact dermatologic surgeries, and were not specifically developed for dermatologic surgery patients and treatments, but adopted from other surgical fields.6 According to the survey conducted on American College of Mohs Surgery members in 2012, 13% to 29% of the surgeons administered antibiotic prophylaxis to immunocompromised patients to prevent SSI while performing dermatologic surgery on noninfected skin,3 although this was not recommended by Journal of the American Academy of Dermatology Advisory Statement. Indeed, the data on the risk of developing SSI after dermatologic surgery in immunosuppressed patients are limited. However, it is possible that due to the insufficient evidence on the risk of SSI occurrence in this patient group, dermatologic surgeons tend to overuse perioperative antibiotic prophylaxis. To make specific recommendations on the use of antibiotic prophylaxis in immunosuppressed patients in the field of skin surgery, more information about the incidence of SSI after dermatologic surgery in these patients is needed. The aim of this study was to fill this data gap by investigating whether there is an increased risk of SSI after skin surgery in immunocompromised patients compared with immunocompetent patients. Y1 - 2018 U6 - https://doi.org/10.1097/DSS.0000000000001615 IS - 44 (12) SP - 1525 EP - 1536 PB - Wolters Kluwer ER - TY - JOUR A1 - Rittweger, Jörn A1 - Albracht, Kirsten A1 - Flück, Martin A1 - Ruoss, Severin A1 - Brocca, Lorenza A1 - Longa, Emanuela A1 - Moriggi, Manuela A1 - Seynnes, Olivier A1 - Di Giulio, Irene A1 - Tenori, Leonardo A1 - Vignoli, Alessia A1 - Capri, Miriam A1 - Gelfi, Cecilia A1 - Luchinat, Claudio A1 - Franceschi, Claudio A1 - Bottinelli, Roberto A1 - Cerretelli, Paolo A1 - Narici, Marco T1 - Sarcolab pilot study into skeletal muscle’s adaptation to longterm spaceflight JF - npj Microgravity Y1 - 2018 U6 - https://doi.org/10.1038/s41526-018-0052-1 SN - 2373-8065 VL - 4 IS - 1 SP - 1 EP - 9 PB - Nature Portfolio ER - TY - JOUR A1 - Ketelhut, Maike A1 - Göll, Fabian A1 - Braunstein, Björn A1 - Albracht, Kirsten A1 - Abel, Dirk T1 - Comparison of different training algorithms for the leg extension training with an industrial robot JF - Current Directions in Biomedical Engineering N2 - 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. KW - Rehabilitation Technology and Prosthetics KW - Surgical Navigation and Robotics Y1 - 2018 U6 - https://doi.org/10.1515/cdbme-2018-0005 SN - 2364-5504 VL - 4 IS - 1 SP - 17 EP - 20 PB - De Gruyter CY - Berlin ER - TY - JOUR A1 - Werkhausen, Amelie A1 - Albracht, Kirsten A1 - Cronin, Neil J A1 - Paulsen, Gøran A1 - Bojsen-Møller, Jens A1 - Seynnes, Olivier R T1 - Effect of training-induced changes in achilles tendon stiffness on muscle-tendon behavior during landing JF - Frontiers in physiology N2 - During rapid deceleration of the body, tendons buffer part of the elongation of the muscle-tendon unit (MTU), enabling safe energy dissipation via eccentric muscle contraction. Yet, the influence of changes in tendon stiffness within the physiological range upon these lengthening contractions is unknown. This study aimed to examine the effect of training-induced stiffening of the Achilles tendon on triceps surae muscle-tendon behavior during a landing task. Twenty-one male subjects were assigned to either a 10-week resistance-training program consisting of single-leg isometric plantarflexion (n = 11) or to a non-training control group (n = 10). Before and after the training period, plantarflexion force, peak Achilles tendon strain and stiffness were measured during isometric contractions, using a combination of dynamometry, ultrasound and kinematics data. Additionally, testing included a step-landing task, during which joint mechanics and lengths of gastrocnemius and soleus fascicles, Achilles tendon, and MTU were determined using synchronized ultrasound, kinematics and kinetics data collection. After training, plantarflexion strength and Achilles tendon stiffness increased (15 and 18%, respectively), and tendon strain during landing remained similar. Likewise, lengthening and negative work produced by the gastrocnemius MTU did not change detectably. However, in the training group, gastrocnemius fascicle length was offset (8%) to a longer length at touch down and, surprisingly, fascicle lengthening and velocity were reduced by 27 and 21%, respectively. These changes were not observed for soleus fascicles when accounting for variation in task execution between tests. These results indicate that a training-induced increase in tendon stiffness does not noticeably affect the buffering action of the tendon when the MTU is rapidly stretched. Reductions in gastrocnemius fascicle lengthening and lengthening velocity during landing occurred independently from tendon strain. Future studies are required to provide insight into the mechanisms underpinning these observations and their influence on energy dissipation. KW - achilles tendon KW - energy absorption KW - energy dissipation KW - mechanical buffer KW - stiffness Y1 - 2018 U6 - https://doi.org/10.3389/fphys.2018.00794 SN - 1664-042X IS - 9 PB - Frontiers Research Foundation CY - Lausanne ER - TY - CHAP A1 - Grundmann, Jan Thimo A1 - Bauer, Waldemar A1 - Borchers, Kai A1 - Dumont, Etienne A1 - Grimm, Christian D. A1 - Ho, Tra-Mi A1 - Jahnke, Rico A1 - Lange, Caroline A1 - Maiwald, Volker A1 - Mikulz, Eugen A1 - Quantius, Dominik A1 - Reershemius, Siebo A1 - Renger, Thomas A1 - Riemann, Johannes A1 - Sasaki, Kaname A1 - Seefeldt, Patric A1 - Spietz, Peter A1 - Spröwitz, Tom A1 - Toth, Norbert A1 - Wejmo, Elisabet A1 - Biele, Jens A1 - Krause, Christian A1 - Cerotti, Matteo A1 - Peloni, Alessandro A1 - Dachwald, Bernd T1 - Small Spacecraft Solar Sailing for Small Solar System Body Multiple Rendezvous and Landing T2 - 2018 IEEE Aerospace Conference : 3-10 March 2018 Y1 - 2018 SN - 978-1-5386-2014-4 ER - TY - CHAP A1 - Grundmann, Jan Thimo A1 - Bauer, Waldemar A1 - Biele, Jens A1 - Boden, Ralf A1 - Ceriotti, Matteo A1 - Cordero, Federico A1 - Dachwald, Bernd A1 - Dumont, Etienne A1 - Grimm, Christian A1 - Herčík, David A1 - Herique, Alain A1 - Ho, Tra-Mi A1 - Jahnke, Rico A1 - Koch, Aaron A1 - Kofman, Wlodek A1 - Koncz, Alexander A1 - Krause, Christian A1 - Lange, Caroline A1 - Lichtenheldt, Roy A1 - Maiwald, Volker A1 - Mikschl, Tobias A1 - Mikulz, Eugen A1 - Montenegro, Sergio A1 - Pelivan, Ivanka A1 - Peloni, Alessandro A1 - Plettemeier, Dirk A1 - Quantius, Dominik A1 - Reershemius, Siebo A1 - Renger, Thomas A1 - Riemann, Johannes A1 - Ruffer, Michael A1 - Sasaki, Kaname A1 - Schmitz, Nicole A1 - Seboldt, Wolfgang A1 - Seefeldt, Patric A1 - Spietz, Peter A1 - Spröwitz, Tom A1 - Sznajder, Maciej A1 - Tardivel, Simon A1 - Toth, Norbert A1 - Wejmo, Elisabet A1 - Wolff, Friederike A1 - Ziach, Christian T1 - Efficient massively parallel prospection for ISRU by multiple near-earth asteroid rendezvous using near-term solar sails and'now-term'small spacecraft solutions T2 - 2nd Asteroid Science Intersections with In-Space Mine Engineering – ASIME 2018 N2 - Physical interaction with small solar system bodies (SSSB) is key for in-situ resource utilization (ISRU). The design of mining missions requires good understanding of SSSB properties, including composition, surface and interior structure, and thermal environment. But as the saying goes "If you've seen one asteroid, you've seen one Asteroid": Although some patterns may begin to appear, a stable and reliable scheme of SSSB classification still has to be evolved. Identified commonalities would enable generic ISRU technology and spacecraft design approaches with a high degree of re-use. Strategic approaches require much broader in-depth characterization of the SSSB populations of interest to the ISRU community. The DLR-ESTEC GOSSAMER Roadmap Science Working Groups identified target-flexible Multiple Near-Earth asteroid (NEA) Rendezvous (MNR) as one of the missions only feasible with solar sail propulsion, showed the ability to access any inclination and a wide range of heliocentric distances as well as continuous operation close to Earth's orbit where low delta-v objects reside. Y1 - 2018 N1 - 2nd Asteroid Science Intersections with In-Space Mine Engineering – ASIME 2018 16-17 April 2018, Belval, Luxembourg SP - 1 EP - 33 ER - TY - CHAP A1 - Grundmann, Jan Thimo A1 - Bauer, Waldemar A1 - Biele, Jens A1 - Boden, Ralf A1 - Ceriotti, Matteo A1 - Cordero, Federico A1 - Dachwald, Bernd A1 - Dumont, Etienne A1 - Grimm, Christian D. A1 - Herčík, David A1 - Ho, Tra-Mi A1 - Jahnke, Rico A1 - Koch, Aaron D A1 - Koncz, Alexander A1 - Krause, Christian A1 - Lange, Caroline A1 - Lichtenheldt, Roy A1 - Maiwald, Volker A1 - Mikschl, Tobias A1 - Mikulz, Eugen A1 - Montenegro, Sergio A1 - Pelivan, Ivanka A1 - Peloni, Alessandro A1 - Quantius, Dominik A1 - Reershemius, Siebo A1 - Renger, Thomas A1 - Riemann, Johannes A1 - Ruffer, Michael A1 - Sasaki, Kaname A1 - Schmitz, Nicole A1 - Seboldt, Wolfgang A1 - Seefeldt, Patric A1 - Spietz, Peter A1 - Spröwitz, Tom A1 - Sznajder, Maciej A1 - Tardivel, Simon A1 - Tóth, Norbert A1 - Wejmo, Elisabet A1 - Wolff, Friederike A1 - Ziach, Christian T1 - Small spacecraft based multiple near-earth asteroid rendezvous and landing with near-term solar sails and ‘Now-Term ‘technologies T2 - 69 th International Astronautical Congress (IAC) N2 - Physical interaction with small solar system bodies (SSSB) is the next step in planetary science, planetary in-situ resource utilization (ISRU), and planetary defense (PD). It requires a broader understanding of the surface properties of the target objects, with particular interest focused on those near Earth. Knowledge of composition, multi-scale surface structure, thermal response, and interior structure is required to design, validate and operate missions addressing these three fields. The current level of understanding is occasionally simplified into the phrase, ”If you’ve seen one asteroid, you’ve seen one asteroid”, meaning that the in-situ characterization of SSSBs has yet to cross the threshold towards a robust and stable scheme of classification. This would enable generic features in spacecraft design, particularly for ISRU and science missions. Currently, it is necessary to characterize any potential target object sufficiently by a dedicated pre-cursor mission to design the mission which then interacts with the object in a complex fashion. To open up strategic approaches, much broader in-depth characterization of potential target objects would be highly desirable. In SSSB science missions, MASCOT-like nano-landers and instrument carriers which integrate at the instrument level to their mothership have met interest. By its size, MASCOT is compatible with small interplanetary missions. The DLR-ESTEC Gossamer Roadmap Science Working Groups‘ studies identified Multiple Near-Earth asteroid (NEA) Rendezvous (MNR) as one of the space science missions only feasible with solar sail propulsion. The Solar Polar Orbiter (SPO) study showed the ability to access any inclination, theDisplaced-L1 (DL1) mission operates close to Earth, where objects of interest to PD and for ISRU reside. Other studies outline the unique capability of solar sails to provide access to all SSSB, at least within the orbit of Jupiter, and significant progress has been made to explore the performance envelope of near-term solar sails for MNR. However, it is difficult for sailcraft to interact physically with a SSSB. We expand and extend the philosophy of the recently qualified DLR Gossamer solar sail deployment technology using efficient multiple sub-spacecraft integration to also include landers for one-way in-situ investigations and sample-return missions by synergetic integration and operation of sail and lander. The MASCOT design concept and its characteristic features have created an ideal counterpart for thisand has already been adapted to the needs of the AIM spacecraft, former part of the NASA-ESA AIDA missionDesigning the 69th International Astronautical Congress (IAC), Bremen, Germany, 1-5 October 2018. IAC-18-F1.2.3 Page 2 of 17 combined spacecraft for piggy-back launch accommodation enables low-cost massively parallel access to the NEA population. KW - multiple NEA rendezvous KW - solar sail KW - GOSSAMER-1 KW - MASCOT KW - small spacecraft Y1 - 2018 N1 - 69th International Astronautical Congress (IAC), Bremen, Germany, 1-5 October 2018. https://www.bho-legal.com/1-5-october-2018-69th-international-astronautical-congress-2018-in-bremen-germany/ SP - 1 EP - 18 ER - TY - JOUR A1 - Ciritsis, Alexander A1 - Horbach, Andreas A1 - Staat, Manfred A1 - Kuhl, Christiane K. A1 - Kraemer, Nils Andreas T1 - Porosity and tissue integration of elastic mesh implants evaluated in vitro and in vivo JF - Journal of Biomedical Materials Research: Part B: Applied Biomaterials N2 - Purpose In vivo, a loss of mesh porosity triggers scar tissue formation and restricts functionality. The purpose of this study was to evaluate the properties and configuration changes as mesh deformation and mesh shrinkage of a soft mesh implant compared with a conventional stiff mesh implant in vitro and in a porcine model. Material and Methods Tensile tests and digital image correlation were used to determine the textile porosity for both mesh types in vitro. A group of three pigs each were treated with magnetic resonance imaging (MRI) visible conventional stiff polyvinylidene fluoride meshes (PVDF) or with soft thermoplastic polyurethane meshes (TPU) (FEG Textiltechnik mbH, Aachen, Germany), respectively. MRI was performed with a pneumoperitoneum at a pressure of 0 and 15 mmHg, which resulted in bulging of the abdomen. The mesh-induced signal voids were semiautomatically segmented and the mesh areas were determined. With the deformations assessed in both mesh types at both pressure conditions, the porosity change of the meshes after 8 weeks of ingrowth was calculated as an indicator of preserved elastic properties. The explanted specimens were examined histologically for the maturity of the scar (collagen I/III ratio). Results In TPU, the in vitro porosity increased constantly, in PVDF, a loss of porosity was observed under mild stresses. In vivo, the mean mesh areas of TPU were 206.8 cm2 (± 5.7 cm2) at 0 mmHg pneumoperitoneum and 274.6 cm2 (± 5.2 cm2) at 15 mmHg; for PVDF the mean areas were 205.5 cm2 (± 8.8 cm2) and 221.5 cm2 (± 11.8 cm2), respectively. The pneumoperitoneum-induced pressure increase resulted in a calculated porosity increase of 8.4% for TPU and of 1.2% for PVDF. The mean collagen I/III ratio was 8.7 (± 0.5) for TPU and 4.7 (± 0.7) for PVDF. Conclusion The elastic properties of TPU mesh implants result in improved tissue integration compared to conventional PVDF meshes, and they adapt more efficiently to the abdominal wall. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 827–833, 2018. Y1 - 2018 U6 - https://doi.org/10.1002/jbm.b.33877 SN - 1552-4981 VL - 106 IS - 2 SP - 827 EP - 833 PB - Wiley CY - New York, NY ER - TY - CHAP A1 - Tran, Ngoc Trinh A1 - Matthies, Hermann G. A1 - Stavroulakis, Georgios Eleftherios A1 - Staat, Manfred T1 - Direct plastic structural design by chance constrained programming T2 - 6th European Conference on Computational Mechanics (ECCM 6), 7th European Conference on Computational Fluid Dynamics (ECFD 7), 11-15 June 2018, Glasgow, UK N2 - We propose a stochastic programming method to analyse limit and shakedown of structures under random strength with lognormal distribution. In this investigation a dual chance constrained programming algorithm is developed to calculate simultaneously both the upper and lower bounds of the plastic collapse limit or the shakedown limit. The edge-based smoothed finite element method (ES-FEM) using three-node linear triangular elements is used. Y1 - 2018 ER - TY - CHAP A1 - Artmann, Gerhard A1 - Meruvu, Haritha A1 - Kizildag, Sefa A1 - Temiz Artmann, Aysegül ED - Artmann, Gerhard ED - Temiz Artmann, Aysegül ED - Zhubanova, Azhar A. ED - Digel, Ilya T1 - Functional Toxicology and Pharmacology Test of Cell Induced Mechanical Tensile Stress in 2D and 3D Tissue Cultures T2 - Biological, Physical and Technical Basics of Cell Engineering N2 - Mechanical forces/tensile stresses are critical determinants of cellular growth, differentiation and migration patterns in health and disease. The innovative “CellDrum technology” was designed for measuring mechanical tensile stress of cultured cell monolayers/thin tissue constructs routinely. These are cultivated on very thin silicone membranes in the so-called CellDrum. The cell layers adhere firmly to the membrane and thus transmit the cell forces generated. A CellDrum consists of a cylinder which is sealed from below with a 4 μm thick, biocompatible, functionalized silicone membrane. The weight of cell culture medium bulbs the membrane out downwards. Membrane indentation is measured. When cells contract due to drug action, membrane, cells and medium are lifted upwards. The induced indentation changes allow for lateral drug induced mechanical tension quantification of the micro-tissues. With hiPS-induced (human) Cardiomyocytes (CM) the CellDrum opens new perspectives of individualized cardiac drug testing. Here, monolayers of self-beating hiPS-CMs were grown in CellDrums. Rhythmic contractions of the hiPS-cells induce membrane up-and-down deflections. The recorded cycles allow for single beat amplitude, single beat duration, integration of the single beat amplitude over the beat time and frequency analysis. Dose effects of agonists and antagonists acting on Ca2+ channels were sensitively and highly reproducibly observed. Data were consistent with published reference data as far as they were available. The combination of the CellDrum technology with hiPS-Cardiomyocytes offers a fast, facile and precise system for pharmacological and toxicological studies. It allows new preclinical basic as well as applied research in pharmacolgy and toxicology. Y1 - 2018 SN - 978-981-10-7904-7 U6 - https://doi.org/10.1007/978-981-10-7904-7_7 SP - 157 EP - 192 PB - Springer CY - Singapore ER - TY - CHAP A1 - Jung, Alexander A1 - Frotscher, Ralf A1 - Staat, Manfred T1 - Electromechanical model of hiPSC-derived ventricular cardiomyocytes cocultured with fibroblasts T2 - 6th European Conference on Computational Mechanics (ECCM 6), 7th European Conference on Computational Fluid Dynamics (ECFD 7), 11-15 June 2018, Glasgow, UK N2 - The CellDrum provides an experimental setup to study the mechanical effects of fibroblasts co-cultured with hiPSC-derived ventricular cardiomyocytes. Multi-scale computational models based on the Finite Element Method are developed. Coupled electrical cardiomyocyte-fibroblast models (cell level) are embedded into reaction-diffusion equations (tissue level) which compute the propagation of the action potential in the cardiac tissue. Electromechanical coupling is realised by an excitation-contraction model (cell level) and the active stress arising during contraction is added to the passive stress in the force balance, which determines the tissue displacement (tissue level). Tissue parameters in the model can be identified experimentally to the specific sample. Y1 - 2018 ER -