TY - JOUR A1 - Bhattarai, Aroj A1 - May, Charlotte Anabell A1 - Staat, Manfred A1 - Kowalczyk, Wojciech A1 - Tran, Thanh Ngoc T1 - Layer-specific damage modeling of porcine large intestine under biaxial tension JF - Bioengineering N2 - The mechanical behavior of the large intestine beyond the ultimate stress has never been investigated. Stretching beyond the ultimate stress may drastically impair the tissue microstructure, which consequently weakens its healthy state functions of absorption, temporary storage, and transportation for defecation. Due to closely similar microstructure and function with humans, biaxial tensile experiments on the porcine large intestine have been performed in this study. In this paper, we report hyperelastic characterization of the large intestine based on experiments in 102 specimens. We also report the theoretical analysis of the experimental results, including an exponential damage evolution function. The fracture energies and the threshold stresses are set as damage material parameters for the longitudinal muscular, the circumferential muscular and the submucosal collagenous layers. A biaxial tensile simulation of a linear brick element has been performed to validate the applicability of the estimated material parameters. The model successfully simulates the biomechanical response of the large intestine under physiological and non-physiological loads. KW - biaxial tensile experiment KW - anisotropy KW - hyperelastic KW - constitutive modeling KW - damage Y1 - 2022 U6 - http://dx.doi.org/10.3390/bioengineering9100528 SN - 2306-5354 N1 - Der Artikel gehört zum Sonderheft "Computational Biomechanics" VL - 9 IS - 10, Early Access SP - 1 EP - 17 PB - MDPI CY - Basel 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 - http://dx.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 - JOUR A1 - Bhattarai, Aroj A1 - Staat, Manfred T1 - Computational comparison of different textile implants to correct apical prolapse in females JF - Current Directions in Biomedical Engineering N2 - Prosthetic textile implants of different shapes, sizes and polymers are used to correct the apical prolapse after hysterectomy (removal of the uterus). The selection of the implant before or during minimally invasive surgery depends on the patient’s anatomical defect, intended function after reconstruction and most importantly the surgeon’s preference. Weakness or damage of the supporting tissues during childbirth, menopause or previous pelvic surgeries may put females in higher risk of prolapse. Numerical simulations of reconstructed pelvic floor with weakened tissues and organ supported by textile product models: DynaMesh®-PRS soft, DynaMesh®-PRP soft and DynaMesh®-CESA from FEG Textiletechnik mbH, Germany are compared. Y1 - 2018 U6 - http://dx.doi.org/10.1515/cdbme-2018-0159 VL - 4 IS - 1 SP - 661 EP - 664 PB - De Gruyter CY - Berlin ER - TY - JOUR A1 - Bhattarai, Aroj A1 - Staat, Manfred T1 - A computational study of organ relocation after laparoscopic pectopexy to repair posthysterectomy vaginal vault prolapse JF - Computer Methods in Biomechanics and Biomedical Engineering: Imaging & Visualization Y1 - 2019 U6 - http://dx.doi.org/10.1080/21681163.2019.1670095 SN - 2168-1171 PB - Taylor & Francis CY - London ER - TY - JOUR A1 - Birgel, Stefan A1 - Leschinger, Tim A1 - Wegmann, Kilian A1 - Staat, Manfred T1 - Calculation of muscle forces and joint reaction loads in the shoulder area via an OpenSim based computer model JF - tm - Technisches Messen N2 - Using the OpenSim software and verified anatomical data, a computer model for the calculation of biomechanical parameters is developed and used to determine the effect of a reattachment of the Supraspinatus muscle with a medial displacement of the muscle attachment point, which may be necessary for a rupture of the supraspinatus tendon. The results include the influence of the operation on basic biomechanical parameters such as the lever arm, as well as the calculated the muscle activations for the supraspinatus and deltoid. In addition, the influence on joint stability is examined by an analysis of the joint reaction force. The study provides a detailed description of the used model, as well as medical findings to a reattachment of the supraspinatus. Mit der Software OpenSim und überprüften anatomischen Daten wird ein Computermodell zur Berechnung von biomechanischen Parametern entwickelt und genutzt, um den Effekt einer Refixierung des Supraspinatusmuskels mit einer medialen Verschiebung des Muskelansatzpunktes zu ermitteln, wie sie unter anderem nach einem Riss der Supraspinatussehne notwendig sein kann. Die Ergebnisse umfassen hierbei den Einfluss der Operation auf grundlegende biomechanische Parameter wie den Hebelarm sowie die berechneten Muskelaktivierungen für den Supraspinatus und Deltoideus. Zusätzlich wird der Einfluss auf die Gelenkstabilität betrachtet und durch eine Analyse der Gelenkreaktionskraft untersucht. Die Studie bietet eine detaillierte Beschreibung des genutzten Modells, sowie medizinische Erkenntnisse zu einer Refixierung des Supraspinatus. Y1 - 2018 U6 - http://dx.doi.org/10.1515/teme-2017-0114 SN - 2196-7113 VL - 85 IS - 5 SP - 321 EP - 330 PB - De Gruyter CY - Berlin ER - TY - JOUR A1 - Blome, Hans-Joachim A1 - Seboldt, Wolfgang A1 - Dachwald, Bernd A1 - Richter, Lutz T1 - Proposal for an integrated European Space Exploration Study JF - Space Debris and Space Traffic Management Symposium 2004 : proceedings of the International Academy of Astronautics Space Debris and Space Traffic Management Symposium, held in conjunction with the 55th International Astronautical Congress (IAC), October 4 - 8, 2004, Vancouver, British Columbia, Canada / ed. by Joerg Bendisch Y1 - 2004 SN - 0-87703-523-7 N1 - Proceedings IAC-2004-IAA, 3.6.1.06; Space Debris and Space Traffic Management Symposium <2004, Vancouver, British Columbia> ; International Academy of Astronautics PB - Univelt CY - San Diego, Calif. ER - TY - JOUR A1 - Brockhaus, Moritz K. A1 - Behbahani, Mehdi A1 - Muris, Farina A1 - Jansen, Sebastian V. A1 - Schmitz- Rode, Thomas A1 - Steinseifer, Ulrich A1 - Clauser, Johanna C. T1 - In vitro thrombogenicity testing of pulsatile mechanical circulatory support systems: Design and proof-of-concept JF - Artificial Organs N2 - Thrombogenic complications are a main issue in mechanical circulatory support (MCS). There is no validated in vitro method available to quantitatively assess the thrombogenic performance of pulsatile MCS devices under realistic hemodynamic conditions. The aim of this study is to propose a method to evaluate the thrombogenic potential of new designs without the use of complex in-vivo trials. This study presents a novel in vitro method for reproducible thrombogenicity testing of pulsatile MCS systems using low molecular weight heparinized porcine blood. Blood parameters are continuously measured with full blood thromboelastometry (ROTEM; EXTEM, FIBTEM and a custom-made analysis HEPNATEM). Thrombus formation is optically observed after four hours of testing. The results of three experiments are presented each with two parallel loops. The area of thrombus formation inside the MCS device was reproducible. The implantation of a filter inside the loop catches embolizing thrombi without a measurable increase of platelet activation, allowing conclusions of the place of origin of thrombi inside the device. EXTEM and FIBTEM parameters such as clotting velocity (α) and maximum clot firmness (MCF) show a total decrease by around 6% with a characteristic kink after 180 minutes. HEPNATEM α and MCF rise within the first 180 minutes indicate a continuously increasing activation level of coagulation. After 180 minutes, the consumption of clotting factors prevails, resulting in a decrease of α and MCF. With the designed mock loop and the presented protocol we are able to identify thrombogenic hot spots inside a pulsatile pump and characterize their thrombogenic potential. Y1 - 2021 U6 - http://dx.doi.org/10.1111/aor.14046 SN - 1525-1594 VL - 45 IS - 12 SP - 1513 EP - 1521 PB - Wiley CY - Weinheim ER - TY - JOUR A1 - Burkhardt, Klaus A1 - Schwarz, Sonja A1 - Pan, Chengrui A1 - Stelter, Felix A1 - Kotliar, Konstantin A1 - Eynatten, Maxilian von A1 - Sollinger, Daniel A1 - Lanzl, Ines A1 - Heemann, Uwe A1 - Baumann, Marcus T1 - Myeloid-related protein 8/14 complex describes microcirculatory alterations in patients with type 2 diabetes and nephropathy JF - Cardiovascular Diabetology Y1 - 2009 SN - 1475-2840 VL - 8 IS - 10 SP - 1 EP - 8 PB - - ER - TY - JOUR A1 - Campen, R. A1 - Kowalski, Julia A1 - Lyons, W.B. A1 - Tulaczyk, S. A1 - Dachwald, Bernd A1 - Pettit, E. A1 - Welch, K. A. A1 - Mikucki, J.A. T1 - Microbial diversity of an Antarctic subglacial community and high‐resolution replicate sampling inform hydrological connectivity in a polar desert JF - Environmental Microbiology Y1 - 2019 U6 - http://dx.doi.org/10.1111/1462-2920.14607 SN - 1462-2920 IS - accepted article PB - Wiley CY - Weinheim ER - TY - JOUR A1 - Capri, Miriam A1 - Morsiani, Cristina A1 - Santoro, Aurelia A1 - Moriggi, Manuela A1 - Conte, Maria A1 - Martucci, Morena A1 - Bellavista, Elena A1 - Fabbri, Cristina A1 - Giampieri, Enrico A1 - Albracht, Kirsten A1 - Flück, Martin A1 - Ruoss, Severin A1 - Brocca, Lorenza A1 - Canepari, Monica A1 - Longa, Emanuela A1 - Giulio, Irene Di A1 - Bottinelli, Roberto A1 - Cerretelli, Paolo A1 - Salvioli, Stefano A1 - Gelfi, Cecilia A1 - Franceschi, Claudio A1 - Narici, Marco A1 - Rittweger, Jörn T1 - Recovery from 6-month spaceflight at the International Space Station: muscle-related stress into a proinflammatory setting JF - The FASEB journal : official publication of the Federation of American Societies for Experimental Biology Y1 - 2019 U6 - http://dx.doi.org/10.1096/fj.201801625R VL - 33 IS - 4 SP - 5168 EP - 5180 ER -