@techreport{BhattaraiFrotscherDurongetal.2016,
  author    = {Bhattarai, Aroj and Frotscher, Ralf and Durong, Minh Tu{\´a}n and Staat, Manfred},
  title     = {Schlussbericht zu BINGO. Optimierung des Systems Netzimplantat-Beckenboden zur therapeutischen Gewebeverst{\"a}rkung nach der Integraltheorie.},
  address   = {Aachen},
  pages     = {34},
  year      = {2016},
  language  = {de}
}
@inproceedings{BhattaraiFrotscherSoraetal.2014,
  author    = {Bhattarai, Aroj and Frotscher, Ralf and Sora, M.-C. and Staat, Manfred},
  title     = {A 3D finite element model of the female pelvic floor for the reconstruction of urinary incontinence},
  series = {11th World Congress on Computational Mechanics (WCCM XI) ; 5th European Conference on Computational Mechanics (ECCM V) ; 6th European Conference on Computational Fluid Dynamics (ECFD VI) ; July 20-25, 2014, Barcelona},
  booktitle = {11th World Congress on Computational Mechanics (WCCM XI) ; 5th European Conference on Computational Mechanics (ECCM V) ; 6th European Conference on Computational Fluid Dynamics (ECFD VI) ; July 20-25, 2014, Barcelona},
  editor    = {Onate, E.},
  organization    = {World Congress on Computational Mechanics <11, 2014, Barcelona>},
  pages     = {1 -- 12},
  year      = {2014},
  language  = {en}
}
@inproceedings{BhattaraiFrotscherStaat2015,
  author    = {Bhattarai, Aroj and Frotscher, Ralf and Staat, Manfred},
  title     = {Biomechanical study of the female pelvic floor dysfunction using the finite element method},
  series = {Conference proceedings of the YIC GACM 2015 : 3rd ECCOMAS Young Investigators Conference and 6th GACM Colloquium on Computational Mechanics , Aachen , Germany, 20.07.2015 - 23.07.2015 / ed.: Stefanie Elgeti ; Jaan-Willem Simon},
  booktitle = {Conference proceedings of the YIC GACM 2015 : 3rd ECCOMAS Young Investigators Conference and 6th GACM Colloquium on Computational Mechanics , Aachen , Germany, 20.07.2015 - 23.07.2015 / ed.: Stefanie Elgeti ; Jaan-Willem Simon},
  publisher = {RWTH Aachen University},
  address   = {Aachen},
  organization    = {ECCOMAS Young Investigators Conference <3, 2015, Aachen>},
  pages     = {1 -- 4},
  year      = {2015},
  language  = {en}
}
@inproceedings{BhattaraiFrotscherStaat2016,
  author    = {Bhattarai, Aroj and Frotscher, Ralf and Staat, Manfred},
  title     = {Significance of fibre geometry on passive-active response of pelvic muscles to evaluate pelvic dysfunction},
  series = {BioMedWomen: Proceedings of the international conference on clinical and bioengineering for women's health},
  booktitle = {BioMedWomen: Proceedings of the international conference on clinical and bioengineering for women's health},
  editor    = {Natal Jorge, Renato},
  publisher = {CRC Press},
  address   = {Boca Raton},
  isbn      = {978-1-138-02910-1},
  pages     = {185 -- 188},
  year      = {2016},
  language  = {en}
}
@incollection{BhattaraiFrotscherStaat2018,
  author    = {Bhattarai, Aroj and Frotscher, Ralf and Staat, Manfred},
  title     = {Computational Analysis of Pelvic Floor Dysfunction},
  series = {Women's Health and Biomechanics},
  booktitle = {Women's Health and Biomechanics},
  publisher = {Springer},
  address   = {Cham},
  isbn      = {978-3-319-71574-2},
  doi       = {10.1007/978-3-319-71574-2_17},
  pages     = {217 -- 230},
  year      = {2018},
  abstract  = {Pelvic floor dysfunction (PFD) is characterized by the failure of the levator ani (LA) muscle to maintain the pelvic hiatus, resulting in the descent of the pelvic organs below the pubococcygeal line. This chapter adopts the modified Humphrey material model to consider the effect of the muscle fiber on passive stretching of the LA muscle. The deformation of the LA muscle subjected to intra-abdominal pressure during Valsalva maneuver is compared with the magnetic resonance imaging (MRI) examination of a nulliparous female. Numerical result shows that the fiber-based Humphrey model simulates the muscle behavior better than isotropic constitutive models. Greater posterior movement of the LA muscle widens the levator hiatus due to lack of support from the anococcygeal ligament and the perineal structure as a consequence of birth-related injury and aging. Old and multiparous females with uncontrolled urogenital and rectal hiatus tend to develop PFDs such as prolapse and incontinence.},
  language  = {en}
}
@article{BhattaraiHorbachStaatetal.2022,
  author    = {Bhattarai, Aroj and Horbach, Andreas and Staat, Manfred and Kowalczyk, Wojciech and Tran, Thanh Ngoc},
  title     = {Virgin passive colon biomechanics and a literature review of active contraction constitutive models},
  series = {Biomechanics},
  volume    = {2},
  journal   = {Biomechanics},
  number    = {2},
  publisher = {MDPI},
  address   = {Basel},
  issn      = {2673-7078},
  doi       = {10.3390/biomechanics2020013},
  pages     = {138 -- 157},
  year      = {2022},
  abstract  = {The objective of this paper is to present our findings on the biomechanical aspects of the virgin passive anisotropic hyperelasticity of the porcine colon based on equibiaxial tensile experiments. Firstly, the characterization of the intestine tissues is discussed for a nearly incompressible hyperelastic fiber-reinforced Holzapfel-Gasser-Ogden constitutive model in virgin passive loading conditions. The stability of the evaluated material parameters is checked for the polyconvexity of the adopted strain energy function using positive eigenvalue constraints of the Hessian matrix with MATLAB. The constitutive material description of the intestine with two collagen fibers in the submucosal and muscular layer each has been implemented in the FORTRAN platform of the commercial finite element software LS-DYNA, and two equibiaxial tensile simulations are presented to validate the results with the optical strain images obtained from the experiments. Furthermore, this paper also reviews the existing models of the active smooth muscle cells, but these models have not been computationally studied here. The review part shows that the constitutive models originally developed for the active contraction of skeletal muscle based on Hill's three-element model, Murphy's four-state cross-bridge chemical kinetic model and Huxley's sliding-filament hypothesis, which are mainly used for arteries, are appropriate for numerical contraction numerical analysis of the large intestine.},
  language  = {en}
}
@article{BhattaraiJabbariAndingetal.2018,
  author    = {Bhattarai, Aroj and Jabbari, Medisa and Anding, Ralf and Staat, Manfred},
  title     = {Surgical treatment of vaginal vault prolapse using different prosthetic mesh implants: a finite element analysis},
  series = {tm - Technisches Messen},
  volume    = {85},
  journal   = {tm - Technisches Messen},
  number    = {5},
  publisher = {De Gruyter},
  address   = {Berlin},
  issn      = {2196-7113},
  doi       = {10.1515/teme-2017-0115},
  pages     = {331 -- 342},
  year      = {2018},
  abstract  = {Particularly multiparous elderly women may suffer from vaginal vault prolapse after hysterectomy due to weak support from lax apical ligaments. A decreased amount of estrogen and progesterone in older age is assumed to remodel the collagen thereby reducing tissue stiffness. Sacrocolpopexy is either performed as open or laparoscopic surgery using prosthetic mesh implants to substitute lax ligaments. Y-shaped mesh models (DynaMesh, Gynemesh, and Ultrapro) are implanted in a 3D female pelvic floor finite element model in the extraperitoneal space from the vaginal cuff to the first sacral (S1) bone below promontory. Numerical simulations are conducted during Valsalva maneuver with weakened tissues modeled by reduced tissue stiffness. Tissues are modeled as incompressible, isotropic hyperelastic materials whereas the meshes are modeled either as orthotropic linear elastic or as isotropic hyperlastic materials. The positions of the vaginal cuff and the bladder base are calculated from the pubococcygeal line for female pelvic floor at rest, for prolapse and after repair using the three meshes. Due to mesh mechanics and mesh pore deformation along the loaded direction, the DynaMesh with regular rectangular mesh pores is found to provide better mechanical support to the organs than the Gynemesh and the Ultrapro with irregular hexagonal mesh pores. Insbesondere {\"a}ltere, mehrgeb{\"a}hrende Frauen leiden h{\"a}ufiger an einem Scheidenvorfall nach einer Hysterektomie aufgrund der schwachen Unterst{\"u}tzung durch laxe apikale B{\"a}nder. Es wird angenommen, dass eine verringerte Menge an {\"O}strogen und Progesteron im h{\"o}heren Alter das Kollagen umformt, wodurch die Gewebesteifigkeit reduziert wird. Die Sakrokolpopexie ist eine offene oder laparoskopische Operation, die mit prothetischen Netzimplantaten durchgef{\"u}hrt wird, um laxe B{\"a}nder zu ersetzen. Y-f{\"o}rmige Netzmodelle (DynaMesh, Gynemesh und Ultrapro) werden in einem 3D-Modell des weiblichen Beckenbodens im extraperitonealen Raum vom Vaginalstumpf bis zum Promontorium implantiert. Numerische Simulationen werden w{\"a}hrend des Valsalva-Man{\"o}vers mit geschw{\"a}chtem Gewebe durchgef{\"u}hrt, das durch eine reduzierte Gewebesteifigkeit modelliert wird. Die Gewebe werden als inkompressible, isotrop hyperelastische Materialien modelliert, w{\"a}hrend die Netze entweder als orthotrope linear elastische oder als isotrope hyperlastische Materialien modelliert werden. Die Positionen des Vaginalstumpfs, der Blase und der Harnr{\"o}hrenachse werden anhand der Pubococcygeallinie aus der Ruhelage, f{\"u}r den Prolaps und nach der Reparatur unter Verwendung der drei Netze berechnet. Aufgrund der Netzmechanik und der Netzporenverformung bietet das DynaMesh mit regelm{\"a}ßigen rechteckigen Netzporen eine bessere mechanische Unterst{\"u}tzung und eine Neupositionierung des Scheidengew{\"o}lbes, der Blase und der Urethraachse als Gynemesh und Ultrapro mit unregelm{\"a}ßigen hexagonalen Netzporen.},
  language  = {en}
}
@article{BhattaraiMayStaatetal.2022,
  author    = {Bhattarai, Aroj and May, Charlotte Anabell and Staat, Manfred and Kowalczyk, Wojciech and Tran, Thanh Ngoc},
  title     = {Layer-specific damage modeling of porcine large intestine under biaxial tension},
  series = {Bioengineering},
  volume    = {9},
  journal   = {Bioengineering},
  number    = {10, Early Access},
  publisher = {MDPI},
  address   = {Basel},
  issn      = {2306-5354},
  doi       = {10.3390/bioengineering9100528},
  pages     = {1 -- 17},
  year      = {2022},
  abstract  = {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.},
  language  = {en}
}
@inproceedings{BhattaraiStaat2016,
  author    = {Bhattarai, Aroj and Staat, Manfred},
  title     = {Female pelvic floor dysfunction: progress weakening of the support system},
  series = {1st YRA MedTech Symposium 2016 : April 8th / 2016 / University of Duisburg-Essen},
  booktitle = {1st YRA MedTech Symposium 2016 : April 8th / 2016 / University of Duisburg-Essen},
  editor    = {Erni, Daniel},
  publisher = {Universit{\"a}t Duisburg-Essen},
  address   = {Duisburg},
  organization    = {MedTech Symposium},
  doi       = {10.17185/duepublico/40821},
  pages     = {11 -- 12},
  year      = {2016},
  abstract  = {The structure of the female pelvic floor (PF) is an inter-related system of bony pelvis,muscles, pelvic organs, fascias, ligaments, and nerves with multiple functions. Mechanically, thepelvic organ support system are of two types: (I) supporting system of the levator ani (LA) muscle,and (II) the suspension system of the endopelvic fascia condensation [1], [2]. Significantdenervation injury to the pelvic musculature, depolimerization of the collagen fibrils of the softvaginal hammock, cervical ring and ligaments during pregnancy and vaginal delivery weakens thenormal functions of the pelvic floor. Pelvic organ prolapse, incontinence, sexual dysfunction aresome of the dysfunctions which increases progressively with age and menopause due toweakened support system according to the Integral theory [3]. An improved 3D finite elementmodel of the female pelvic floor as shown in Fig. 1 is constructed that: (I) considers the realisticsupport of the organs to the pelvic side walls, (II) employs the improvement of our previous FEmodel [4], [5] along with the patient based geometries, (III) incorporates the realistic anatomy andboundary conditions of the endopelvic (pubocervical and rectovaginal) fascia, and (IV) considersvarying stiffness of the endopelvic fascia in the craniocaudal direction [3]. Several computationsare carried out on the presented computational model with healthy and damaged supportingtissues, and comparisons are made to understand the physiopathology of the female PF disorders.},
  language  = {en}
}
@article{BhattaraiStaat2018,
  author    = {Bhattarai, Aroj and Staat, Manfred},
  title     = {Modelling of Soft Connective Tissues to Investigate Female Pelvic Floor Dysfunctions},
  series = {Computational and Mathematical Methods in Medicine},
  volume    = {2018},
  journal   = {Computational and Mathematical Methods in Medicine},
  number    = {Article ID 9518076},
  publisher = {Hindawi},
  address   = {New York, NY},
  issn      = {1748-6718},
  doi       = {10.1155/2018/9518076},
  pages     = {1 -- 16},
  year      = {2018},
  abstract  = {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.},
  language  = {en}
}
@incollection{BhattaraiStaat2018,
  author    = {Bhattarai, Aroj and Staat, Manfred},
  title     = {Mechanics of soft tissue reactions to textile mesh implants},
  series = {Biological, Physical and Technical Basics of Cell Engineering},
  booktitle = {Biological, Physical and Technical Basics of Cell Engineering},
  editor    = {Artmann, Gerhard and Temiz Artmann, Ayseg{\"u}l and Zhubanova, Azhar A. and Digel, Ilya},
  publisher = {Springer},
  address   = {Singapore},
  isbn      = {978-981-10-7904-7},
  doi       = {10.1007/978-981-10-7904-7_11},
  pages     = {251 -- 275},
  year      = {2018},
  abstract  = {For pelvic floor disorders that cannot be treated with non-surgical procedures, minimally invasive surgery has become a more frequent and safer repair procedure. More than 20 million prosthetic meshes are implanted each year worldwide. The simple selection of a single synthetic mesh construction for any level and type of pelvic floor dysfunctions without adopting the design to specific requirements increase the risks for mesh related complications. Adverse events are closely related to chronic foreign body reaction, with enhanced formation of scar tissue around the surgical meshes, manifested as pain, mesh erosion in adjacent structures (with organ tissue cut), mesh shrinkage, mesh rejection and eventually recurrence. Such events, especially scar formation depend on effective porosity of the mesh, which decreases discontinuously at a critical stretch when pore areas decrease making the surgical reconstruction ineffective that further augments the re-operation costs. The extent of fibrotic reaction is increased with higher amount of foreign body material, larger surface, small pore size or with inadequate textile elasticity. Standardized studies of different meshes are essential to evaluate influencing factors for the failure and success of the reconstruction. Measurements of elasticity and tensile strength have to consider the mesh anisotropy as result of the textile structure. An appropriate mesh then should show some integration with limited scar reaction and preserved pores that are filled with local fat tissue. This chapter reviews various tissue reactions to different monofilament mesh implants that are used for incontinence and hernia repairs and study their mechanical behavior. This helps to predict the functional and biological outcomes after tissue reinforcement with meshes and permits further optimization of the meshes for the specific indications to improve the success of the surgical treatment.},
  language  = {en}
}
@inproceedings{BhattaraiStaat2018,
  author    = {Bhattarai, Aroj and Staat, Manfred},
  title     = {Pectopexy to repair vaginal vault prolapse: a finite element approach},
  series = {Proceedings CMBBE 2018},
  booktitle = {Proceedings CMBBE 2018},
  editor    = {Fernandes, P.R. and Tavares, J. M.},
  year      = {2018},
  abstract  = {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.},
  language  = {en}
}
@article{BhattaraiStaat2018,
  author    = {Bhattarai, Aroj and Staat, Manfred},
  title     = {Computational comparison of different textile implants to correct apical prolapse in females},
  series = {Current Directions in Biomedical Engineering},
  volume    = {4},
  journal   = {Current Directions in Biomedical Engineering},
  number    = {1},
  publisher = {De Gruyter},
  address   = {Berlin},
  doi       = {10.1515/cdbme-2018-0159},
  pages     = {661 -- 664},
  year      = {2018},
  abstract  = {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.},
  language  = {en}
}
@article{BhattaraiStaat2019,
  author    = {Bhattarai, Aroj and Staat, Manfred},
  title     = {A computational study of organ relocation after laparoscopic pectopexy to repair posthysterectomy vaginal vault prolapse},
  series = {Computer Methods in Biomechanics and Biomedical Engineering: Imaging \& Visualization},
  journal   = {Computer Methods in Biomechanics and Biomedical Engineering: Imaging \& Visualization},
  publisher = {Taylor \& Francis},
  address   = {London},
  issn      = {2168-1171},
  doi       = {10.1080/21681163.2019.1670095},
  year      = {2019},
  language  = {en}
}
@inproceedings{BirgelLeschingerWegmannetal.2017,
  author    = {Birgel, Stefan and Leschinger, Tim and Wegmann, Kilian and Staat, Manfred},
  title     = {Calculation of muscle forces and joint reaction loads in shoulder area via an OpenSim based computer calculation},
  series = {2nd YRA MedTech Symposium 2017 : June 8th - 9th / 2017 / Hochschule Ruhr-West},
  booktitle = {2nd YRA MedTech Symposium 2017 : June 8th - 9th / 2017 / Hochschule Ruhr-West},
  editor    = {Erni, Daniel and Fischerauer, Alice and Himmel, J{\"o}rg and Seeger, Thomas and Thelen, Klaus},
  publisher = {Universit{\"a}t Duisburg-Essen},
  address   = {Duisburg},
  organization    = {MedTech Symposium},
  isbn      = {978-3-9814801-9-1},
  doi       = {10.17185/duepublico/43984},
  pages     = {116 -- 117},
  year      = {2017},
  language  = {en}
}
@article{BirgelLeschingerWegmannetal.2018,
  author    = {Birgel, Stefan and Leschinger, Tim and Wegmann, Kilian and Staat, Manfred},
  title     = {Calculation of muscle forces and joint reaction loads in the shoulder area via an OpenSim based computer model},
  series = {tm - Technisches Messen},
  volume    = {85},
  journal   = {tm - Technisches Messen},
  number    = {5},
  publisher = {De Gruyter},
  address   = {Berlin},
  issn      = {2196-7113},
  doi       = {10.1515/teme-2017-0114},
  pages     = {321 -- 330},
  year      = {2018},
  abstract  = {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 {\"u}berpr{\"u}ften 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 f{\"u}r den Supraspinatus und Deltoideus. Zus{\"a}tzlich wird der Einfluss auf die Gelenkstabilit{\"a}t 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.},
  language  = {en}
}
@techreport{BlandfordDachwaldDigeletal.2015,
  author    = {Blandford, Daniel and Dachwald, Bernd and Digel, Ilya and Espe, Clemens and Feldmann, Marco and Francke, Gero and Hiecke, Hannah and Kowalski, Julia and Lindner, Peter and Plescher, Engelbert and Sch{\"o}ngarth, Sarah},
  title     = {Enceladus Explorer : Schlussbericht — Version: 1.0},
  publisher = {FH Aachen},
  address   = {Aachen},
  doi       = {10.2314/GBV:86319950X},
  year      = {2015},
  language  = {de}
}
@article{BlomeSeboldtDachwaldetal.2004,
  author    = {Blome, Hans-Joachim and Seboldt, Wolfgang and Dachwald, Bernd and Richter, Lutz},
  title     = {Proposal for an integrated European Space Exploration Study},
  series = {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},
  journal   = {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},
  publisher = {Univelt},
  address   = {San Diego, Calif.},
  isbn      = {0-87703-523-7},
  pages     = {XI, 432 S. : Ill., graph. Darst.},
  year      = {2004},
  language  = {en}
}
@misc{BlottnerHastermannMuckeltetal.2019,
  author    = {Blottner, Dieter and Hastermann, Maria and Muckelt, Paul and Albracht, Kirsten and Schoenrock, Britt and Salanova, Michele and Warner, Martin and Gunga, Hans-Christian and Stokes, Maria},
  title     = {MYOTONES - Inflight muscle health status monitoring during long-duration space missions onboard the International Space Station: a single case study},
  series = {IAC Papers Archive},
  journal   = {IAC Papers Archive},
  publisher = {Pergamon},
  address   = {Oxford},
  issn      = {00741795},
  pages     = {2 Seiten},
  year      = {2019},
  abstract  = {The MYOTONES experiment is the first to monitor changes in the basic biomechanical properties (tone, elasticity and stiffness) of the resting human myofascial system due to microgravity with a oninvasive, portable device on board the ISS. The MyotonPRO device applies several brief mechanical stimuli to the surface of the skin, and the natural oscillation signals of the tissue beneath are detected and computed by the MyotonPRO. Thus, an objective, quick and easy determination of the state of the underlying tissue is possible. Two preflight, four inflight and four post flight measurements were performed on a male astronaut using the same 10 measurement points (MP) for each session. MPs were located on the plantar fascia, Achilles tendon, M. soleus, M. gastrocnemius, M. multifidus, M. splenius capitis, M. deltoideus anterior, M. rectus femoris, infrapatellar tendon, M. tibialis anterior. Subcutaneous tissues thickness above the MPs was measured using ultrasound imaging. Magnetic resonance images (MRI) of lower limb muscles and functional tests were also performed pre- and postflight. Our first measurements on board the ISS confirmed increased tone and stiffness of the lumbar multifidus muscle, an important trunk stabilizer, dysfunction of which is known to be associated with back pain. Furthermore, reduced tone and stiffness of Achilles tendon and plantar fascia were observed inflight vs. preflight, confirming previous findings from terrestrial analog studies and parabolic flights. Unexpectedly, the deltoid showed negative inflight changes in tone and stiffness, and increased elasticity, suggesting a potential risk of muscle atrophy in longer spaceflight that should be addressed by adequate inflight countermeasure protocols. Most values from limb and back MPS showed deflected patterns (in either directions) from inflight shortly after the re-entry phase on the landing day and one week later. Most parameter values then normalized to baseline after 3 weeks likely due to 1G re-adaptation and possible outcome of the reconditioning protocol. No major changes in subcutaneous tissues thickness above the MPs were found inflight vs preflight, suggesting no bias (i.e., fluid shift, extreme tissue thickening or loss). Pre- and postflight MRI and functional tests showed negligible changes in calf muscle size, power and force, which is likely due to training effects from current inflight exercise protocols. The MYOTONES experiment is currently ongoing to collect data from further crew members. The potential impact of this research is to better understand the effects of microgravity and countermeasures over the time course of an ISS mission cycle. This will enable exercise countermeasures to be tailored},
  language  = {en}
}
@inproceedings{BlumAlbannaBenninghausetal.2019,
  author    = {Blum, Yannik and Albanna, Walid and Benninghaus, Anne and Kotliar, Konstantin},
  title     = {Vasomotion in retinal vessels of patients presenting post hemorrhagic hydrocephalus following subarachnoid hemorrhage},
  series = {3rd YRA MedTech Symposium 2019 : May 24 / 2019 / FH Aachen},
  booktitle = {3rd YRA MedTech Symposium 2019 : May 24 / 2019 / FH Aachen},
  editor    = {Staat, Manfred and Erni, Daniel},
  publisher = {Universit{\"a}t Duisburg-Essen},
  address   = {Duisburg},
  organization    = {MedTech Symposium},
  isbn      = {978-3-940402-22-6},
  doi       = {10.17185/duepublico/48750},
  pages     = {38 -- 39},
  year      = {2019},
  abstract  = {Clearance of blood components and fluid drainage play a crucial role in subarachnoid hemorrhage (SAH) and post hemorrhagic hydrocephalus (PHH). With the involvement of interstitial fluid (ISF) and cerebrospinal fluid (CSF), two pathways for the clearance of fluid and solutes in the brain are proposed. Starting at the level of capillaries, flow of ISF follows along the basement membranes in the walls of cerebral arteries out of the parenchyma to drain into the lymphatics and CSF [1]-[3]. Conversely, it is shown that CSF enters the parenchyma between glial and pial basement membranes of penetrating arteries [4]-[6]. Nevertheless, the involved structures and the contribution of either flow pathway to fluid balance between the subarachnoid space and interstitial space remains controversial. Low frequency oscillations in vascular tone are referred to as vasomotion and corresponding vasomotion waves are modeled as the driving force for flow of ISF out of the parenchyma [7]. Retinal vessel analysis (RVA) allows non-invasive measurement of retinal vessel vasomotion with respect to diameter changes [8]. Thus, the aim of the study is to investigate vasomotion in RVA signals of SAH and PHH patients.},
  language  = {en}
}
@incollection{BorggrafeOhndorfDachwaldetal.2012,
  author    = {Borggrafe, Andreas and Ohndorf, Andreas and Dachwald, Bernd and Seboldt, Wolfgang},
  title     = {Analysis of interplanetary solar sail trajectories with attitude dynamics},
  series = {Dynamics and Control of Space Systems 2012},
  booktitle = {Dynamics and Control of Space Systems 2012},
  publisher = {Univelt Inc},
  address   = {San Diego},
  isbn      = {978-0-87703-587-9},
  pages     = {1553 -- 1569},
  year      = {2012},
  abstract  = {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.},
  language  = {en}
}
@inproceedings{BorggraefeDachwald2010,
  author    = {Borggr{\"a}fe, Andreas and Dachwald, Bernd},
  title     = {Mission performance evaluation for solar sails using a refined SRP force model with variable optical coefficients},
  series = {2nd International Symposium on Solar Sailing},
  booktitle = {2nd International Symposium on Solar Sailing},
  pages     = {1 -- 6},
  year      = {2010},
  abstract  = {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.},
  language  = {en}
}
@inproceedings{BraunsteinGoldmannAlbrachtetal.2013,
  author    = {Braunstein, Bjoern and Goldmann, Jan-Peter and Albracht, Kirsten and Sanno, Maximilian and Willwacher, Steffen and Heinrich, Kai and Herrmann, Volker and Br{\"u}ggemann, Gert-Peter},
  title     = {Joint specific contribution of mechanical power and work during acceleration and top speed in elite sprinters},
  series = {31 International Conference on Biomechanics in Sports, Taipei, Taiwan, July 07 - July 22, 2013},
  booktitle = {31 International Conference on Biomechanics in Sports, Taipei, Taiwan, July 07 - July 22, 2013},
  issn      = {1999-4168},
  year      = {2013},
  language  = {en}
}
@article{BrockhausBehbahaniMurisetal.2021,
  author    = {Brockhaus, Moritz K. and Behbahani, Mehdi and Muris, Farina and Jansen, Sebastian V. and Schmitz- Rode, Thomas and Steinseifer, Ulrich and Clauser, Johanna C.},
  title     = {In vitro thrombogenicity testing of pulsatile mechanical circulatory support systems: Design and proof-of-concept},
  series = {Artificial Organs},
  volume    = {45},
  journal   = {Artificial Organs},
  number    = {12},
  publisher = {Wiley},
  address   = {Weinheim},
  issn      = {1525-1594},
  doi       = {10.1111/aor.14046},
  pages     = {1513 -- 1521},
  year      = {2021},
  abstract  = {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.},
  language  = {en}
}
@article{BurkhardtSchwarzPanetal.2009,
  author    = {Burkhardt, Klaus and Schwarz, Sonja and Pan, Chengrui and Stelter, Felix and Kotliar, Konstantin and Eynatten, Maxilian von and Sollinger, Daniel and Lanzl, Ines and Heemann, Uwe and Baumann, Marcus},
  title     = {Myeloid-related protein 8/14 complex describes microcirculatory alterations in patients with type 2 diabetes and nephropathy},
  series = {Cardiovascular Diabetology},
  volume    = {8},
  journal   = {Cardiovascular Diabetology},
  number    = {10},
  publisher = {-},
  isbn      = {1475-2840},
  pages     = {1 -- 8},
  year      = {2009},
  language  = {en}
}
@article{CampenKowalskiLyonsetal.2019,
  author    = {Campen, R. and Kowalski, Julia and Lyons, W.B. and Tulaczyk, S. and Dachwald, Bernd and Pettit, E. and Welch, K. A. and Mikucki, J.A.},
  title     = {Microbial diversity of an Antarctic subglacial community and high-resolution replicate sampling inform hydrological connectivity in a polar desert},
  series = {Environmental Microbiology},
  journal   = {Environmental Microbiology},
  number    = {accepted article},
  publisher = {Wiley},
  address   = {Weinheim},
  issn      = {1462-2920},
  doi       = {10.1111/1462-2920.14607},
  year      = {2019},
  language  = {en}
}
@article{CapriMorsianiSantoroetal.2019,
  author    = {Capri, Miriam and Morsiani, Cristina and Santoro, Aurelia and Moriggi, Manuela and Conte, Maria and Martucci, Morena and Bellavista, Elena and Fabbri, Cristina and Giampieri, Enrico and Albracht, Kirsten and Fl{\"u}ck, Martin and Ruoss, Severin and Brocca, Lorenza and Canepari, Monica and Longa, Emanuela and Giulio, Irene Di and Bottinelli, Roberto and Cerretelli, Paolo and Salvioli, Stefano and Gelfi, Cecilia and Franceschi, Claudio and Narici, Marco and Rittweger, J{\"o}rn},
  title     = {Recovery from 6-month spaceflight at the International Space Station: muscle-related stress into a proinflammatory setting},
  series = {The FASEB journal : official publication of the Federation of American Societies for Experimental Biology},
  volume    = {33},
  journal   = {The FASEB journal : official publication of the Federation of American Societies for Experimental Biology},
  number    = {4},
  doi       = {10.1096/fj.201801625R},
  pages     = {5168 -- 5180},
  year      = {2019},
  language  = {en}
}
@inproceedings{CarzanaDachwaldNoomen2017,
  author    = {Carzana, Livio and Dachwald, Bernd and Noomen, Ron},
  title     = {Model and trajectory optimization for an ideal laser-enhanced solar sail},
  series = {68th International Astronautical Congress},
  booktitle = {68th International Astronautical Congress},
  year      = {2017},
  abstract  = {A laser-enhanced solar sail is a solar sail that is not solely propelled by solar radiation but additionally by a laser beam that illuminates the sail. This way, the propulsive acceleration of the sail results from the combined action of the solar and the laser radiation pressure onto the sail. The potential source of the laser beam is a laser satellite that coverts solar power (in the inner solar system) or nuclear power (in the outer solar system) into laser power. Such a laser satellite (or many of them) can orbit anywhere in the solar system and its optimal orbit (or their optimal orbits) for a given mission is a subject for future research. This contribution provides the model for an ideal laser-enhanced solar sail and investigates how a laser can enhance the thrusting capability of such a sail. The term "ideal" means that the solar sail is assumed to be perfectly reflecting and that the laser beam is assumed to have a constant areal power density over the whole sail area. Since a laser beam has a limited divergence, it can provide radiation pressure at much larger solar distances and increase the radiation pressure force into the desired direction. Therefore, laser-enhanced solar sails may make missions feasible, that would otherwise have prohibitively long flight times, e.g. rendezvous missions in the outer solar system. This contribution will also analyze exemplary mission scenarios and present optimial trajectories without laying too much emphasis on the design and operations of the laser satellites. If the mission studies conclude that laser-enhanced solar sails would have advantages with respect to "traditional" solar sails, a detailed study of the laser satellites and the whole system architecture would be the second next step},
  language  = {en}
}
@article{CehreliAkpinarTemizArtmannetal.2015,
  author    = {Cehreli, Ruksan and Akpinar, Hale and Temiz Artmann, Ayseg{\"u}l and Sagol, Ozgul},
  title     = {Effects of Glutamine and Omega-3 Fatty Acids on Erythrocyte Deformability and Oxidative Damage in Rat Model of Enterocolitis},
  series = {Gastroenterology Research},
  volume    = {8},
  journal   = {Gastroenterology Research},
  number    = {5},
  issn      = {1918-2813},
  doi       = {10.14740/gr683w},
  pages     = {265 -- 273},
  year      = {2015},
  language  = {en}
}
@article{ChloeMalyaranCraveiroetal.2022,
  author    = {Chlo{\´e}, Radermacher and Malyaran, Hanna and Craveiro, Rogerio Bastos and Peglow, Sarah and Behbahani, Mehdi and Pufe, Thomas and Wolf, Michael and Neuss, Sabine},
  title     = {Mechanical loading on cementoblasts: a mini review},
  series = {Osteologie},
  volume    = {31},
  journal   = {Osteologie},
  number    = {2},
  publisher = {Thieme},
  address   = {Stuttgart},
  issn      = {1019-1291},
  doi       = {10.1055/a-1826-0777},
  pages     = {111 -- 118},
  year      = {2022},
  abstract  = {Orthodontic treatments are concomitant with mechanical forces and thereby cause teeth movements. The applied forces are transmitted to the tooth root and the periodontal ligaments which is compressed on one side and tensed up on the other side. Indeed, strong forces can lead to tooth root resorption and the crown-to-tooth ratio is reduced with the potential for significant clinical impact. The cementum, which covers the tooth root, is a thin mineralized tissue of the periodontium that connects the periodontal ligament with the tooth and is build up by cementoblasts. The impact of tension and compression on these cells is investigated in several in vivo and in vitro studies demonstrating differences in protein expression and signaling pathways. In summary, osteogenic marker changes indicate that cyclic tensile forces support whereas static tension inhibits cementogenesis. Furthermore, cementogenesis experiences the same protein expression changes in static conditions as static tension, but cyclic compression leads to the exact opposite of cyclic tension. Consistent with marker expression changes, the singaling pathways of Wnt/ß-catenin and RANKL/OPG show that tissue compression leads to cementum degradation and tension forces to cementogenesis. However, the cementum, and in particular its cementoblasts, remain a research area which should be explored in more detail to understand the underlying mechanism of bone resorption and remodeling after orthodontic treatments.},
  language  = {en}
}
@article{CiobanuStaatRahimi2008,
  author    = {Ciobanu, Octavian and Staat, Manfred and Rahimi, Alireza},
  title     = {The use of open source software in biomechanical finite element analysis},
  series = {Buletinul Institutului Politehnic din Ia{\c{s}}i / Universitatea Tehnică Gh. Asachi, Ia{\c{s}}i Secţia 5, Construcţii de ma{\c{s}}ini = Machine construction = Bulletin of the Polytechnic Institute of Jassy = Izvestija Jasskogo Politechničeskogo Instituta},
  volume    = {54},
  journal   = {Buletinul Institutului Politehnic din Ia{\c{s}}i / Universitatea Tehnică Gh. Asachi, Ia{\c{s}}i Secţia 5, Construcţii de ma{\c{s}}ini = Machine construction = Bulletin of the Polytechnic Institute of Jassy = Izvestija Jasskogo Politechničeskogo Instituta},
  number    = {7/8},
  issn      = {1011-2855},
  pages     = {213 -- 220},
  year      = {2008},
  language  = {en}
}
@article{CiritsisHorbachStaatetal.2018,
  author    = {Ciritsis, Alexander and Horbach, Andreas and Staat, Manfred and Kuhl, Christiane K. and Kraemer, Nils Andreas},
  title     = {Porosity and tissue integration of elastic mesh implants evaluated in vitro and in vivo},
  series = {Journal of Biomedical Materials Research: Part B: Applied Biomaterials},
  volume    = {106},
  journal   = {Journal of Biomedical Materials Research: Part B: Applied Biomaterials},
  number    = {2},
  publisher = {Wiley},
  address   = {New York, NY},
  issn      = {1552-4981},
  doi       = {10.1002/jbm.b.33877},
  pages     = {827 -- 833},
  year      = {2018},
  abstract  = {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.},
  language  = {en}
}
@article{ColomboDriraFrotscheretal.2022,
  author    = {Colombo, Daniele and Drira, Slah and Frotscher, Ralf and Staat, Manfred},
  title     = {An element-based formulation for ES-FEM and FS-FEM models for implementation in standard solid mechanics finite element codes for 2D and 3D static analysis},
  series = {International Journal for Numerical Methods in Engineering},
  volume    = {124},
  journal   = {International Journal for Numerical Methods in Engineering},
  number    = {2},
  publisher = {Wiley},
  address   = {Chichester},
  issn      = {1097-0207},
  doi       = {10.1002/nme.7126},
  pages     = {402 -- 433},
  year      = {2022},
  abstract  = {Edge-based and face-based smoothed finite element methods (ES-FEM and FS-FEM, respectively) are modified versions of the finite element method allowing to achieve more accurate results and to reduce sensitivity to mesh distortion, at least for linear elements. These properties make the two methods very attractive. However, their implementation in a standard finite element code is nontrivial because it requires heavy and extensive modifications to the code architecture. In this article, we present an element-based formulation of ES-FEM and FS-FEM methods allowing to implement the two methods in a standard finite element code with no modifications to its architecture. Moreover, the element-based formulation permits to easily manage any type of element, especially in 3D models where, to the best of the authors' knowledge, only tetrahedral elements are used in FS-FEM applications found in the literature. Shape functions for non-simplex 3D elements are proposed in order to apply FS-FEM to any standard finite element.},
  language  = {en}
}
@article{ConzenAlbannaWeissetal.2018,
  author    = {Conzen, Catharina and Albanna, Walid and Weiss, Miriam and K{\"u}rten, David and Vilser, Walthard and Kotliar, Konstantin and Z{\"a}ske, Charlotte and Clusmann, Hans and Schubert, Gerrit Alexander},
  title     = {Vasoconstriction and Impairment of Neurovascular Coupling after Subarachnoid Hemorrhage: a Descriptive Analysis of Retinal Changes},
  series = {Translational Stroke Research},
  journal   = {Translational Stroke Research},
  number    = {9},
  publisher = {Springer Nature},
  address   = {Cham},
  issn      = {1868-601X},
  doi       = {10.1007/s12975-017-0585-8},
  pages     = {284 -- 293},
  year      = {2018},
  abstract  = {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.},
  language  = {en}
}
@article{Dachwald2005,
  author    = {Dachwald, Bernd},
  title     = {Optimization of very-low-thrust trajectories using evolutionary neurocontrol},
  series = {Acta Astronautica. 57 (2005), H. 2-8},
  journal   = {Acta Astronautica. 57 (2005), H. 2-8},
  isbn      = {0094-5765},
  pages     = {175 -- 185},
  year      = {2005},
  language  = {en}
}
@article{Dachwald2004,
  author    = {Dachwald, Bernd},
  title     = {Minimum Transfer Times for Nonperfectly Reflecting Solar Sailcraft},
  series = {Journal of Spacecraft and Rockets. 41 (2004), H. 4},
  journal   = {Journal of Spacecraft and Rockets. 41 (2004), H. 4},
  isbn      = {0022-4650},
  pages     = {693 -- 695},
  year      = {2004},
  language  = {en}
}
@article{Dachwald2005,
  author    = {Dachwald, Bernd},
  title     = {Optimal Solar Sail Trajectories for Missions to the Outer Solar System},
  series = {Journal of guidance, control, and dynamics. 28 (2005), H. 6},
  journal   = {Journal of guidance, control, and dynamics. 28 (2005), H. 6},
  isbn      = {0162-3192},
  pages     = {1187 -- 1193},
  year      = {2005},
  language  = {en}
}
@article{Dachwald2004,
  author    = {Dachwald, Bernd},
  title     = {Optimization of Interplanetary Solar Sailcraft Trajectories Using Evolutionary Neurocontrol},
  series = {Journal of guidance, control, and dynamics. 27 (2004), H. 1},
  journal   = {Journal of guidance, control, and dynamics. 27 (2004), H. 1},
  isbn      = {0162-3192},
  pages     = {66 -- 72},
  year      = {2004},
  language  = {en}
}
@article{Dachwald2004,
  author    = {Dachwald, Bernd},
  title     = {Interplanetary Mission Analysis for Non-Perfectly Reflecting Solar Sailcraft Using Evolutionary Neurocontrol},
  series = {Astrodynamics 2003 : proceedings of the AAS/AIAA Astrodynamics Conference held August 3 - 7, 2003, Big Sky, Montana / ed. by Jean de Lafontaine. - Pt. 2. - (Advances in the astronautical sciences ; 116,2)},
  journal   = {Astrodynamics 2003 : proceedings of the AAS/AIAA Astrodynamics Conference held August 3 - 7, 2003, Big Sky, Montana / ed. by Jean de Lafontaine. - Pt. 2. - (Advances in the astronautical sciences ; 116,2)},
  publisher = {Univelt},
  address   = {San Diego, Calif.},
  isbn      = {0-87703-509-1},
  pages     = {1247 -- 1262},
  year      = {2004},
  language  = {en}
}
@article{Dachwald2003,
  author    = {Dachwald, Bernd},
  title     = {Verwendung eines neuronalen Reglers und evolution{\"a}rer Algorithmen zur Berechnung optimaler interplanetarer Sonnenseglerbahnen},
  series = {Deutscher Luft- und Raumfahrtkongress 2003 : M{\"u}nchen, 17. bis 20. November 2003, Motto: 100 Jahre Motorflug - 112 Jahre Menschenflug: Visionen gestalten Zukunft / Deutsche Gesellschaft f{\"u}r Luft- und Raumfahrt - Lilienthal-Oberth e.V. (DGLR). [Red.: Peter Brandt (verantwortlich)]. - Bd. 1. - (Jahrbuch ... der Deutschen Gesellschaft f{\"u}r Luft- und Raumfahrt)},
  journal   = {Deutscher Luft- und Raumfahrtkongress 2003 : M{\"u}nchen, 17. bis 20. November 2003, Motto: 100 Jahre Motorflug - 112 Jahre Menschenflug: Visionen gestalten Zukunft / Deutsche Gesellschaft f{\"u}r Luft- und Raumfahrt - Lilienthal-Oberth e.V. (DGLR). [Red.: Peter Brandt (verantwortlich)]. - Bd. 1. - (Jahrbuch ... der Deutschen Gesellschaft f{\"u}r Luft- und Raumfahrt)},
  address   = {Bonn},
  pages     = {211 -- 218},
  year      = {2003},
  language  = {de}
}
@article{Dachwald2004,
  author    = {Dachwald, Bernd},
  title     = {Low-Thrust Trajectory Optimization and Interplanetary Mission Analysis Using Evolutionary Neurocontrol},
  series = {Deutscher Luft- und Raumfahrtkongress 2004 : Dresden, 20. bis 23. September 2004, Motto: Luft- und Raumfahrt - Br{\"u}cke f{\"u}r eine wissensbasierte Gesellschaft / Deutsche Gesellschaft f{\"u}r Luft- und Raumfahrt - Lilienthal-Oberth e.V. (DGLR). [Red.: Peter Brandt (verantwortlich)]. - Bd. 2. - (Jahrbuch ... der Deutschen Gesellschaft f{\"u}r Luft- und Raumfahrt)},
  journal   = {Deutscher Luft- und Raumfahrtkongress 2004 : Dresden, 20. bis 23. September 2004, Motto: Luft- und Raumfahrt - Br{\"u}cke f{\"u}r eine wissensbasierte Gesellschaft / Deutsche Gesellschaft f{\"u}r Luft- und Raumfahrt - Lilienthal-Oberth e.V. (DGLR). [Red.: Peter Brandt (verantwortlich)]. - Bd. 2. - (Jahrbuch ... der Deutschen Gesellschaft f{\"u}r Luft- und Raumfahrt)},
  address   = {Bonn},
  pages     = {917 -- 926},
  year      = {2004},
  language  = {en}
}
@article{Dachwald2004,
  author    = {Dachwald, Bernd},
  title     = {Evolutionary Neurocontrol: A Smart Method for Global Optimization of Low-Thrust Trajectories},
  series = {22nd AIAA Applied Aerodynamics Conference and Exhibit - AIAA/AAS Astrodynamics Specialist Conference and Exhibit - AIAA Guidance, Navigation, and Control Conference and Exhibit - AIAA Modeling and Simulation Technologies Conference and Exhibit - AIAA Atmospheric Flight Mechanics Conference and Exhibit : 16 - 19 August 2004, Providence, Rhode Island / American Institute of Aeronautics and Astronautics. - (AIAA meeting papers on disc ; 2004,14-15)},
  journal   = {22nd AIAA Applied Aerodynamics Conference and Exhibit - AIAA/AAS Astrodynamics Specialist Conference and Exhibit - AIAA Guidance, Navigation, and Control Conference and Exhibit - AIAA Modeling and Simulation Technologies Conference and Exhibit - AIAA Atmospheric Flight Mechanics Conference and Exhibit : 16 - 19 August 2004, Providence, Rhode Island / American Institute of Aeronautics and Astronautics. - (AIAA meeting papers on disc ; 2004,14-15)},
  publisher = {American Inst. of Aeronautics and Astronautics},
  address   = {Reston, Va.},
  pages     = {2 CD-ROMs},
  year      = {2004},
  language  = {en}
}
@article{Dachwald2004,
  author    = {Dachwald, Bernd},
  title     = {Optimal Solar Sail Trajectories for Missions to the Outer Solar System},
  series = {22nd AIAA Applied Aerodynamics Conference and Exhibit - AIAA/AAS Astrodynamics Specialist Conference and Exhibit - AIAA Guidance, Navigation, and Control Conference and Exhibit - AIAA Modeling and Simulation Technologies Conference and Exhibit - AIAA Atmospheric Flight Mechanics Conference and Exhibit : 16 - 19 August 2004, Providence, Rhode Island / American Institute of Aeronautics and Astronautics. - (AIAA meeting papers on disc ; 2004,14-15)},
  journal   = {22nd AIAA Applied Aerodynamics Conference and Exhibit - AIAA/AAS Astrodynamics Specialist Conference and Exhibit - AIAA Guidance, Navigation, and Control Conference and Exhibit - AIAA Modeling and Simulation Technologies Conference and Exhibit - AIAA Atmospheric Flight Mechanics Conference and Exhibit : 16 - 19 August 2004, Providence, Rhode Island / American Institute of Aeronautics and Astronautics. - (AIAA meeting papers on disc ; 2004,14-15)},
  publisher = {American Inst. of Aeronautics and Astronautics},
  address   = {Reston, Va.},
  pages     = {2 CD-ROMs},
  year      = {2004},
  language  = {en}
}
@inproceedings{Dachwald2007,
  author    = {Dachwald, Bernd},
  title     = {Low-Thrust Mission Analysis and Global Trajectory Optimization Using Evolutionary Neurocontrol: New Results},
  series = {European Workshop on Space Mission Analysis ESA/ESOC, Darmstadt, Germany 10 { 12 Dec 2007},
  booktitle = {European Workshop on Space Mission Analysis ESA/ESOC, Darmstadt, Germany 10 { 12 Dec 2007},
  year      = {2007},
  abstract  = {Interplanetary trajectories for low-thrust spacecraft are often characterized by multiple revolutions around the sun. Unfortunately, the convergence of traditional trajectory optimizers that are based on numerical optimal control methods depends strongly on an adequate initial guess for the control function (if a direct method is used) or for the starting values of the adjoint vector (if an indirect method is used). Especially when many revolutions around the sun are re- quired, trajectory optimization becomes a very difficult and time-consuming task that involves a lot of experience and expert knowledge in astrodynamics and optimal control theory, because an adequate initial guess is extremely hard to find. Evolutionary neurocontrol (ENC) was proposed as a smart method for low-thrust trajectory optimization that fuses artificial neural networks and evolutionary algorithms to so-called evolutionary neurocontrollers (ENCs) [1]. Inspired by natural archetypes, ENC attacks the trajectoryoptimization problem from the perspective of artificial intelligence and machine learning, a perspective that is quite different from that of optimal control theory. Within the context of ENC, a trajectory is regarded as the result of a spacecraft steering strategy that maps permanently the actual spacecraft state and the actual target state onto the actual spacecraft control vector. This way, the problem of searching the optimal spacecraft trajectory is equivalent to the problem of searching (or "learning") the optimal spacecraft steering strategy. An artificial neural network is used to implement such a spacecraft steering strategy. It can be regarded as a parameterized function (the network function) that is defined by the internal network parameters. Therefore, each distinct set of network parameters defines a different network function and thus a different steering strategy. The problem of searching the optimal steering strategy is now equivalent to the problem of searching the optimal set of network parameters. Evolutionary algorithms that work on a population of (artificial) chromosomes are used to find the optimal network parameters, because the parameters can be easily mapped onto a chromosome. The trajectory optimization problem is solved when the optimal chromosome is found. A comparison of solar sail trajectories that have been published by others [2, 3, 4, 5] with ENC-trajectories has shown that ENCs can be successfully applied for near-globally optimal spacecraft control [1, 6] and that they are able to find trajectories that are closer to the (unknown) global optimum, because they explore the trajectory search space more exhaustively than a human expert can do. The obtained trajectories are fairly accurate with respect to the terminal constraint. If a more accurate trajectory is required, the ENC-solution can be used as an initial guess for a local trajectory optimization method. Using ENC, low-thrust trajectories can be optimized without an initial guess and without expert attendance. Here, new results for nuclear electric spacecraft and for solar sail spacecraft are presented and it will be shown that ENCs find very good trajectories even for very difficult problems. Trajectory optimization results are presented for 1. NASA's Solar Polar Imager Mission, a mission to attain a highly inclined close solar orbit with a solar sail [7] 2. a mission to de ect asteroid Apophis with a solar sail from a retrograde orbit with a very-high velocity impact [8, 9] 3. JPL's \2nd Global Trajectory Optimization Competition", a grand tour to visit four asteroids from different classes with a NEP spacecraft},
  language  = {en}
}
@inproceedings{Dachwald2005,
  author    = {Dachwald, Bernd},
  title     = {Global optimization of low-thrust space missions using evolutionary neurocontrol},
  series = {Proceedings of the international workshop on global optimization},
  booktitle = {Proceedings of the international workshop on global optimization},
  pages     = {85 -- 90},
  year      = {2005},
  abstract  = {Low-thrust space propulsion systems enable flexible high-energy deep space missions, but the design and optimization of the interplanetary transfer trajectory is usually difficult. It involves much experience and expert knowledge because the convergence behavior of traditional local trajectory optimization methods depends strongly on an adequate initial guess. Within this extended abstract, evolutionary neurocontrol, a method that fuses artificial neural networks and evolutionary algorithms, is proposed as a smart global method for low-thrust trajectory optimization. It does not require an initial guess. The implementation of evolutionary neurocontrol is detailed and its performance is shown for an exemplary mission.},
  language  = {en}
}
@incollection{Dachwald2017,
  author    = {Dachwald, Bernd},
  title     = {Light propulsion systems for spacecraft},
  series = {Optical nano and micro actuator technology},
  booktitle = {Optical nano and micro actuator technology},
  editor    = {Knopf, George K. and Otani, Yukitoshi},
  publisher = {CRC Press},
  address   = {Boca Raton},
  isbn      = {9781315217628 (eBook)},
  pages     = {577 -- 598},
  year      = {2017},
  language  = {en}
}
@incollection{Dachwald2010,
  author    = {Dachwald, Bernd},
  title     = {Solar sail dynamics and control},
  series = {Encyclopedia of Aerospace Engineering},
  booktitle = {Encyclopedia of Aerospace Engineering},
  publisher = {Wiley},
  address   = {Hoboken},
  doi       = {10.1002/9780470686652.eae292},
  year      = {2010},
  abstract  = {Solar sails are large and lightweight reflective structures that are propelled by solar radiation pressure. This chapter covers their orbital and attitude dynamics and control. First, the advantages and limitations of solar sails are discussed and their history and development status is outlined. Because the dynamics of solar sails is governed by the (thermo-)optical properties of the sail film, the basic solar radiation pressure force models have to be described and compared before parameters to measure solar sail performance can be defined. The next part covers the orbital dynamics of solar sails for heliocentric motion, planetocentric motion, and motion at Lagrangian equilibrium points. Afterwards, some advanced solar radiation pressure force models are described, which allow to quantify the thrust force on solar sails of arbitrary shape, the effects of temperature, of light incidence angle, of surface roughness, and the effects of optical degradation of the sail film in the space environment. The orbital motion of a solar sail is strongly coupled to its rotational motion, so that the attitude control of these soft and flexible structures is very challenging, especially for planetocentric orbits that require fast attitude maneuvers. Finally, some potential attitude control methods are sketched and selection criteria are given.},
  language  = {en}
}
@article{Dachwald2005,
  author    = {Dachwald, Bernd},
  title     = {Optimization of very-low-thrust trajectories using evolutionary neurocontrol},
  series = {Acta Astronautica},
  volume    = {57},
  journal   = {Acta Astronautica},
  number    = {2-8},
  publisher = {Elsevier},
  address   = {Amsterdam [u.a.]},
  isbn      = {1879-2030},
  pages     = {175 -- 185},
  year      = {2005},
  abstract  = {Searching optimal interplanetary trajectories for low-thrust spacecraft is usually a difficult and time-consuming task that involves much experience and expert knowledge in astrodynamics and optimal control theory. This is because the convergence behavior of traditional local optimizers, which are based on numerical optimal control methods, depends on an adequate initial guess, which is often hard to find, especially for very-low-thrust trajectories that necessitate many revolutions around the sun. The obtained solutions are typically close to the initial guess that is rarely close to the (unknown) global optimum. Within this paper, trajectory optimization problems are attacked from the perspective of artificial intelligence and machine learning. Inspired by natural archetypes, a smart global method for low-thrust trajectory optimization is proposed that fuses artificial neural networks and evolutionary algorithms into so-called evolutionary neurocontrollers. This novel method runs without an initial guess and does not require the attendance of an expert in astrodynamics and optimal control theory. This paper details how evolutionary neurocontrol works and how it could be implemented. The performance of the method is assessed for three different interplanetary missions with a thrust to mass ratio <0.15mN/kg (solar sail and nuclear electric).},
  language  = {en}
}
@inproceedings{Dachwald2017,
  author    = {Dachwald, Bernd},
  title     = {Radiation pressure force model for an ideal laser-enhanced solar sail},
  series = {4th International Symposium on Solar Sailing},
  booktitle = {4th International Symposium on Solar Sailing},
  pages     = {1 -- 5},
  year      = {2017},
  abstract  = {The concept of a laser-enhanced solar sail is introduced and the radiation pressure force model for an ideal laser-enhanced solar sail is derived. A laser-enhanced solar sail is a "traditional" solar sail that is, however, not solely propelled by solar radiation, but additionally by a laser beam that illuminates the sail. The additional laser radiation pressure increases the sail's propulsive force and can give, depending on the location of the laser source, more control authority over the direction of the solar sail's propulsive force vector. This way, laser-enhanced solar sails may augment already existing solar sail mission concepts and make novel mission concepts feasible.},
  language  = {en}
}
@inproceedings{Dachwald2004,
  author    = {Dachwald, Bernd},
  title     = {Solar sail performance requirements for missions to the outer solar system and beyond},
  series = {55th International Astronautical Congress 2004},
  booktitle = {55th International Astronautical Congress 2004},
  doi       = {10.2514/6.IAC-04-S.P.11},
  pages     = {1 -- 9},
  year      = {2004},
  abstract  = {Solar sails enable missions to the outer solar system and beyond, although the solar radiation pressure decreases with the square of solar distance. For such missions, the solar sail may gain a large amount of energy by first making one or more close approaches to the sun. Within this paper, optimal trajectories for solar sail missions to the outer planets and into near interstellar space (200 AU) are presented. Thereby, it is shown that even near/medium-term solar sails with relatively moderate performance allow reasonable transfer times to the boundaries of the solar system.},
  language  = {en}
}