@article{BauerSterner, author = {Bauer, Franz and Sterner, Michael}, title = {Impacts of lifestyle changes on energy demand and greenhouse gas emissions in Germany}, series = {Renewable and Sustainable Energy Reviews}, volume = {207}, journal = {Renewable and Sustainable Energy Reviews}, publisher = {Elsevier}, address = {Amsterdam}, issn = {1364-0321}, doi = {10.1016/j.rser.2024.114944}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-77682}, pages = {17}, abstract = {Most energy scenario studies typically focus on technological options and fuel substitution for decarbonising future energy systems. Lifestyle changes are rarely considered, although they can significantly reduce energy demand and climate change mitigation efforts. By using an energy system model, this study shows that it is possible to reduce final energy demand in Germany by 61 \% in 2050 relative to 2019 levels, resulting in an annual per capita energy demand of 44 GJ for a representative country of the Global North. This goal can be achieved through a combination of technological measures and lifestyle changes without sacrificing a decent standard of living. Societal chances can eliminate reliance on not-yet-established negative emission technologies, reduce energy dependency, and reduce the need for energy-intensive hydrogen and e-fuels. Downsizing the energy system provides an opportunity for strengthening climate change mitigation, decrease material demand and reduce land use.}, language = {en} } @inproceedings{RuikenLandmannZoelleretal., author = {Ruiken, Axel and Landmann, Philipp and Z{\"o}ller, Ralf and Wolff, Thomas}, title = {Untersuchungen zum Tragverhalten von Einfach- und Mehrfachverbundankern im Zuge des BA 2/2 der A281 in Bremen}, series = {Vortr{\"a}ge der 38. Baugrundtagung, 25. bis 27. September 2024, Bremen}, booktitle = {Vortr{\"a}ge der 38. Baugrundtagung, 25. bis 27. September 2024, Bremen}, publisher = {Aktiv Druck \& Verlag GmbH}, address = {Ebelsbach}, organization = {Deutsche Gesellschaft f{\"u}r Geotechnik e.V. (DGGT)}, isbn = {978-3-932653-57-5}, doi = {10.35096/othr/pub-7766}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-77662}, pages = {129 -- 135}, abstract = {Im Vorfeld zum Neubau der A281 BA2/2 in Bremen wurden u.a. 14 Eignungsanker hergestellt und das Lastabtragsverhalten in den anstehenden Wesersanden ermittelt. Die Verpressk{\"o}rper wurden in Sanden mit mitteldichter und dichter Lagerung angeordnet und dabei die L{\"a}nge und Anzahl der Verpressk{\"o}rper systematisch variiert. Neben der Messung von Kraft und Verschiebung am Ankerkopf wurde mithilfe hochaufl{\"o}sender faseroptischer Instrumentierung von Verpressk{\"o}rpern und Ankerlitzen der Lastabtrag {\"u}ber den reinen Verpressk{\"o}rper hinaus {\"u}ber die gesamte Verbundl{\"a}nge ermittelt. Anhand der Ergebnisse wird die sukzessive Aktivierung der Baugrundwiderst{\"a}nde sichtbar. Die Ergebnisse zeigen einen n{\"a}herungsweise linearen Zusammenhang zwischen den untersuchten 6 m bis 12 m langen Verpressk{\"o}rpern und den ermittelten Herausziehwiderst{\"a}nden im Sand und somit ein deutlich g{\"u}nstigeres Lastabtragsverhalten, als es bisherige Erfahrungen gezeigt haben.}, language = {de} } @article{AlbrechtHellerbrandWeiningeretal., author = {Albrecht, Sophie Viktoria and Hellerbrand, Stefan and Weininger, Florian and Thiel, Charlotte}, title = {Strategies for Minimizing Environmental Impact in Construction: A Case Study of a Cementitious 3D Printed Lost Formwork for a Staircase}, series = {materials}, volume = {18}, journal = {materials}, publisher = {MDPI}, doi = {10.3390/ma18040825}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-79236}, pages = {18}, abstract = {The construction industry faces significant challenges, including environmental sustainability, rising material costs, and a shortage of skilled labor. Digital fabrication technologies offer innovative solutions to address these issues by reducing raw material consumption and waste generation. Among these, 3D printing technologies offer distinct advantages over traditional construction methods, particularly in handling complex geometries. However, the significant environmental impact of cement in 3D printed concrete, due to its high rheological and printability requirements, remains a concern. This study introduces a novel application of 3D printed permanent formwork in the construction of a winder staircase, assessed through an Environmental Life Cycle Assessment (LCA) from cradle to gate. By comparing the environmental impacts of various construction materials and processes, this study highlights the comparative advantages and disadvantages of conventional methods versus 3D printing. The LCA results reveal that traditional production methods, particularly those using plywood formwork, exhibit higher environmental impacts. In contrast, timber formwork performs better than most 3D printed mixtures in terms of Global Warming Potential (GWP), Acidification Potential (AP), and abiotic depletion potential (ADP). The findings of this study underscore the potential of additive manufacturing for sustainable construction, particularly through the use of low-clinker cement in 3D printed formwork, offering a promising pathway towards reducing the environmental footprint of construction activities}, language = {en} } @article{WestnerReichenederMatschi, author = {Westner, Markus and Reicheneder, Matthias and Matschi, Markus}, title = {From Captive Centers to Global Integration}, series = {Information Resources Management Journal}, volume = {38}, journal = {Information Resources Management Journal}, number = {1}, publisher = {IGI Global}, issn = {1533-7979}, doi = {10.4018/IRMJ.373322}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-80406}, pages = {25}, abstract = {Contemporary developments in virtual work and global talent management are transforming information technology (IT) nearshoring and offshoring practices, yet research on organizational responses remains limited. Through expert interviews with 33 IT executives (76\% chief information officers) from Germany's top 500 companies, this article examines organizational models, strategies, and good practices in IT nearshoring and offshoring. It reveals a shift from traditional captive centers toward fully integrated global teams, enabling high-value task delivery and reflecting increased workforce maturity. Companies are expanding their operations driven by talent needs rather than cost savings, with success factors including employee integration and robust on-site management. This study contributes to theory and practice by providing a framework for understanding organizational models in global IT delivery and offering actionable insights for executives, emphasizing workforce integration over geographical separation.}, subject = {Offshoring}, language = {en} } @article{HauslerHolznerEhrnspergeretal., author = {Hausler, Peter and Holzner, Lukas and Ehrnsperger, Matthias and Bierl, Rudolf}, title = {Evaluation of the creep strength of samples produced by fused deposition modeling}, series = {Open Engineering}, volume = {14}, journal = {Open Engineering}, number = {1}, publisher = {de Gruyter}, doi = {10.1515/eng-2024-0084}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-79760}, pages = {10}, abstract = {Data sheets for 3D printing materials typically include softening temperature, impact strength, tensile strength, and stiffness. However, creep strength, an important parameter for components used over an extended period, is usually not included. Nevertheless, this parameter is of significant importance for components that are used over an extended period of time.This study compares the long-term creep behavior of a selection of materials that are commonly used in fused deposition modeling 3D printing. The materials under investigation are acrylonitrile butadiene styrene, acrylonitrile styrene acrylate, polylactic acid, and polycarbonate. In addition, the influence of fiber reinforcements on these materials is also examined. A simple, reproducible test procedure is proposed for users to determine and compare creep resistance of materials. This enables developers to select materials suitable for their own requirements on creep resistance and allows 3D-printing users to compare different materials. Results suggest that fiber reinforcement generally improves creep stability in 3D-printing materials, with GreenTEC Pro Carbon and add:north PC Blend HT LCF showing the most promise in this study.}, language = {en} } @incollection{Leinweber, author = {Leinweber, Juliane}, title = {Digitale Versorgung in der Logop{\"a}die/Sprachtherapie Von der Pr{\"a}senz- und Videotherapie zur Teletherapie}, series = {Digitale Technik f{\"u}r ambulante Pflege und Therapie II - Impulse f{\"u}r die Praxis}, booktitle = {Digitale Technik f{\"u}r ambulante Pflege und Therapie II - Impulse f{\"u}r die Praxis}, editor = {Weber, Karsten and Haug, Sonja and Lauer, Norina and Mohr, Christa and Pfingsten, Andrea and Raptis, Georgios and Bahr, Gudrun}, publisher = {transcript}, address = {Bielefeld}, doi = {10.14361/9783839467275-012}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-65039}, pages = {145 -- 152}, language = {de} } @misc{OPUS4-7391, title = {Digitale Technik f{\"u}r ambulante Pflege und Therapie III}, editor = {Weber, Karsten and Haug, Sonja and Lauer, Norina and Mohr, Christa and Pfingsten, Andrea and Raptis, Georgios and Bahr, Gudrun}, edition = {1. Aufl.}, publisher = {transcript}, address = {Bielefeld}, isbn = {978-3-8394-6728-2}, doi = {10.14361/9783839467282}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-73914}, abstract = {Dieser Artikel untersucht die Machbarkeit und Wirksamkeit einer physiotherapeutischen Tele-Intervention bei Schlaganfallpatient*innen. Die prospektive, nicht kontrollierte Interventionsstudie basiert auf einem Mixed-Methods-Design und analysiert funktionelle Ver{\"a}nderungen sowie die Lebensqualit{\"a}t der Teilnehmenden vor und nach der Intervention. Eingeschlossen wurden postakute und chronische Schlaganfallpatient*innen mit stabilen Krankheitsbildern, die in ihrem h{\"a}uslichen Umfeld lebten. Die Intervention bestand aus videobasierten Einzelsitzungen und einer optionalen Gruppenintervention, die Physiotherapie und Logop{\"a}die kombinierte. Die Ergebnisse zeigten signifikante Verbesserungen in der Arm-Hand-Funktion und der Teilhabef{\"a}higkeit. Die Teletherapie erwies sich als eine praktikable Erg{\"a}nzung zur traditionellen Rehabilitation, insbesondere in l{\"a}ndlichen Regionen, und f{\"o}rderte die Autonomie und das aktive Engagement der Patient*innen in ihrem Genesungsprozess. Die Studie belegt das Potenzial teletherapeutischer Maßnahmen zur {\"U}berbr{\"u}ckung von Versorgungsl{\"u}cken und zur Sicherstellung einer kontinuierlichen, hochfrequenten Rehabilitation.}, subject = {AAL-Technik}, language = {de} } @article{GradZentgrafSchultheissetal., author = {Grad, Marius and Zentgraf, Jan and Schultheiss, Ulrich and Esper, Lukas and Diemar, Andreas and Noster, Ulf and Spiess, Lothar}, title = {Effect of Carbon Content on the Phase Composition, Microstructure and Mechanical Properties of the TiC Layer Formed in Hot-Pressed Titanium-Steel Composites}, series = {Metals}, volume = {14}, journal = {Metals}, number = {9}, publisher = {MDPI AG}, issn = {2075-4701}, doi = {10.3390/met14090959}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-74617}, abstract = {During the hot pressing of pure titanium and different carbon steels in a temperature range of ϑ = 950-1050 °C, a compound layer up to dL≈10 μm thick is formed at the titanium-steel interface. With a higher carbon content of the used steel, the layer thickness increases. The carbon concentration within the layer is in the range of stoichiometry for TiC. Apart from TiC, no other phases can be detected by X-ray diffraction (XRD) measurements inside the formed layer. The calculation of the activation energy for the TiC layer formation is Q = 126.5-136.7 kJ mol-1 and is independent of the carbon content of the steel. The resulting microstructure has a grain size gradient, wherein the mechanical properties, such as hardness and Young's modulus, are almost constant. Statistical analysis using Response Surface Methodology (RSM) indicates that the carbon content of the steel has the most significant influence on layer thickness, followed by annealing temperature and annealing time. By selecting the appropriate carbon steel and the subsequent removal of the steel, it is possible to produce targeted TiC layers on titanium substrates, which holds enormous potential for this material in wear-intensive applications.}, language = {en} } @article{AltmannSchleglVolbert, author = {Altmann, Matthias and Schlegl, Peter and Volbert, Klaus}, title = {A low-power wireless system for energy consumption analysis at mains sockets}, series = {EURASIP Journal on Embedded Systems}, journal = {EURASIP Journal on Embedded Systems}, number = {1}, publisher = {Springer Nature}, doi = {10.1186/s13639-016-0041-y}, pages = {18}, abstract = {Introduction: Improving energy efficiency and reducing energy wastage is an important topic of our time. But it is quite difficult to figure out how much of our total electricity bill can be mapped to which device or at what time the device used it. We believe energy efficiency of normal households can be improved, if this kind of transparency would be available. In this article, we present a system for energy measurement at mains sockets to gain a transparent view of energy consumption for each device in a household. It consists of several smart energy measuring devices (SEMDs) that use a low-power radio protocol to dynamically build and connect to a radio network to transfer power usage date to a server. At the server, the data is stored and can be accessed via web interface. Results: Our primary goal was to build a back-end system for an energy metering platform with very low energy consumption. This platform can provide data for a variety of services that enables users (the consumers) to understand and improve their energy consumption behavior and increase overall energy efficiency of their households.}, language = {en} } @article{MayerRabindranathBoerneretal., author = {Mayer, Matthias and Rabindranath, Raman and B{\"o}rner, Juliane and H{\"o}rner, Eva and Bentz, Alexander and Salgado, Josefina and Han, Hong and B{\"o}se, Holger and Probst, J{\"o}rn and Shamonin (Chamonine), Mikhail and Monkman, Gareth J. and Schlunck, G{\"u}nther}, title = {Ultra-Soft PDMS-Based Magnetoactive Elastomers as Dynamic Cell Culture Substrata}, series = {PLoS ONE}, volume = {8}, journal = {PLoS ONE}, number = {10}, publisher = {PLOS}, doi = {10.1371/journal.pone.0076196}, abstract = {Mechanical cues such as extracellular matrix stiffness and movement have a major impact on cell differentiation and function. To replicate these biological features in vitro, soft substrata with tunable elasticity and the possibility for controlled surface translocation are desirable. Here we report on the use of ultra-soft (Young's modulus <100 kPa) PDMS-based magnetoactive elastomers (MAE) as suitable cell culture substrata. Soft non-viscous PDMS (<18 kPa) is produced using a modified extended crosslinker. MAEs are generated by embedding magnetic microparticles into a soft PDMS matrix. Both substrata yield an elasticity-dependent (14 vs. 100 kPa) modulation of α-smooth muscle actin expression in primary human fibroblasts. To allow for static or dynamic control of MAE material properties, we devise low magnetic field (≈40 mT) stimulation systems compatible with cell-culture environments. Magnetic field-instigated stiffening (14 to 200 kPa) of soft MAE enhances the spreading of primary human fibroblasts and decreases PAX-7 transcription in human mesenchymal stem cells. Pulsatile MAE movements are generated using oscillating magnetic fields and are well tolerated by adherent human fibroblasts. This MAE system provides spatial and temporal control of substratum material characteristics and permits novel designs when used as dynamic cell culture substrata or cell culture-coated actuator in tissue engineering applications or biomedical devices.}, language = {en} } @article{ReinkerBlaesingBierletal., author = {Reinker, Lukas and Bl{\"a}sing, Dominic and Bierl, Rudolf and Ulbricht, Sabina and Dendorfer, Sebastian}, title = {Correlation of Acceleration Curves in Gravitational Direction for Different Body Segments during High-Impact Jumping Exercises}, series = {sensors}, volume = {23}, journal = {sensors}, number = {4}, publisher = {MDPI}, address = {Basel}, doi = {10.3390/s23042276}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-58217}, abstract = {Osteoporosis is a common disease of old age. However, in many cases, it can be very well prevented and counteracted with physical activity, especially high-impact exercises. Wearables have the potential to provide data that can help with continuous monitoring of patients during therapy phases or preventive exercise programs in everyday life. This study aimed to determine the accuracy and reliability of measured acceleration data at different body positions compared to accelerations at the pelvis during different jumping exercises. Accelerations at the hips have been investigated in previous studies with regard to osteoporosis prevention. Data were collected using an IMU-based motion capture system (Xsens) consisting of 17 sensors. Forty-nine subjects were included in this study. The analysis shows the correlation between impacts and the corresponding drop height, which are dependent on the respective exercise. Very high correlations (0.83-0.94) were found between accelerations at the pelvis and the other measured segments at the upper body. The foot sensors provided very weak correlations (0.20-0.27). Accelerations measured at the pelvis during jumping exercises can be tracked very well on the upper body and upper extremities, including locations where smart devices are typically worn, which gives possibilities for remote and continuous monitoring of programs.}, language = {en} } @article{RusavyCechovaDendorferetal., author = {Rusavy, Zdenek and Cechova, Hana and Dendorfer, Sebastian and Kalis, Vladimir and Ismail, Khaled M.}, title = {Is the Finnish grip tight enough? A manometric study of two manual perineal protection techniques}, series = {Acta Obstetricia et Gynecologica Scandinavica}, journal = {Acta Obstetricia et Gynecologica Scandinavica}, edition = {Early view}, publisher = {Wiley}, doi = {10.1111/aogs.15033}, language = {en} } @article{SchmitzNeumannNeumannetal., author = {Schmitz, Paul and Neumann, Christoph Cornelius and Neumann, Carsten and Nerlich, Michael and Dendorfer, Sebastian}, title = {Biomechanical analysis of iliac crest loading following cortico-cancellous bone harvesting}, series = {Journal of Orthopaedic Surgery and Research}, volume = {13}, journal = {Journal of Orthopaedic Surgery and Research}, number = {108}, publisher = {Springer Nature}, doi = {10.1186/s13018-018-0822-1}, pages = {1 -- 8}, abstract = {Background Iliac crest bone harvesting is a frequently performed surgical procedure widely used to treat bone defects. The objective of this study is to assess the biomechanical quantities related to risk for pelvic fracture after harvesting an autologous bone graft at the anterior iliac crest. Methods Finite element models with a simulated harvest site (sized 15 × 20 mm, 15 × 35 mm, 30 × 20 mm and 30 × 35 mm) in the iliac wing are created. The relevant loading case is when the ipsilateral leg is lifted off the ground. Musculoskeletal analysis is utilized to compute the muscle and joint forces involved in this motion. These forces are used as boundary conditions for the finite element analyses. Bone tissue stress is analyzed. Results Critical stress peaks are located between the anterior superior iliac spine (ASIS) and the anterior edge of the harvest site. Irrespective of the graft size, the iliac wing does not show any significant stress peaks with the harvest site being 20 to 25 mm posterior to the ASIS. The harvest area itself inhibits the distribution of the forces applied on the ASIS to extend to the posterior iliac wing. This leads to a lack of stress posterior to the harvest site. A balanced stress distribution with no stress peaks appears when the bone graft is taken below the iliac crest. Conclusion A harvest site located at least 20 to 25 mm posterior to the ASIS should be preferred to minimize the risk of iliac fatigue fracture.}, subject = {Beckenkammknochen}, language = {en} } @article{VoellnerWeberWeberetal., author = {V{\"o}llner, Florian and Weber, Tim A. and Weber, Markus and Renkawitz, Tobias and Dendorfer, Sebastian and Grifka, Joachim and Craiovan, Benjamin}, title = {A simple method for determining ligament stiffness during total knee arthroplasty in vivo}, series = {Scientific Reports}, volume = {9}, journal = {Scientific Reports}, publisher = {Nature}, doi = {10.1038/s41598-019-41732-x}, pages = {1 -- 8}, abstract = {A key requirement in both native knee joints and total knee arthroplasty is a stable capsular ligament complex. However, knee stability is highly individual and ranges from clinically loose to tight. So far, hardly any in vivo data on the intrinsic mechanical of the knee are available. This study investigated if stiffness of the native ligament complex may be determined in vivo using a standard knee balancer. Measurements were obtained with a commercially available knee balancer, which was initially calibrated in vitro. 5 patients underwent reconstruction of the force-displacement curves of the ligament complex. Stiffness of the medial and lateral compartments were calculated to measure the stability of the capsular ligament complex. All force-displacement curves consisted of a non-linear section at the beginning and of a linear section from about 80 N onwards. The medial compartment showed values of 28.4 ± 1.2 N/mm for minimum stiffness and of 39.9 ± 1.1 N/mm for maximum stiffness; the respective values for the lateral compartment were 19.9 ± 0.9 N/mm and 46.6 ± 0.8 N/mm. A commercially available knee balancer may be calibrated for measuring stiffness of knee ligament complex in vivo, which may contribute to a better understanding of the intrinsic mechanical behaviour of knee joints.}, subject = {Biomechanische Analyse}, language = {en} } @article{PutzerAuerMalpicaetal., author = {Putzer, Michael and Auer, Stefan and Malpica, William and S{\"u}ß, Franz and Dendorfer, Sebastian}, title = {A numerical study to determine the effect of ligament stiffness on kinematics of the lumbar spine during flexion}, series = {BMC Musculoskeletal Disorders}, volume = {17}, journal = {BMC Musculoskeletal Disorders}, number = {95}, doi = {10.1186/s12891-016-0942-x}, abstract = {Background There is a wide range of mechanical properties of spinal ligaments documented in literature. Due to the fact that ligaments contribute in stabilizing the spine by limiting excessive intersegmental motion, those properties are of particular interest for the implementation in musculoskeletal models. The aim of this study was to investigate the effect of varying ligament stiffness on the kinematic behaviour of the lumbar spine. Methods A musculoskeletal model with a detailed lumbar spine was modified according to fluoroscopic recordings and corresponding data files of three different subjects. For flexion, inverse dynamics analysis with a variation of the ligament stiffness matrix were conducted. The influence of several degrees of ligament stiffness on the lumbar spine model were investigated by tracking ligament forces, disc forces and resulting moments generated by the ligaments. Additionally, the kinematics of the motion segments were evaluated. Results An increase of ligament stiffness resulted in an increase of ligament and disc forces, whereas the relative change of disc force increased at a higher rate at the L4/L5 level (19 \%) than at the L3/L4 (10 \%) level in a fully flexed posture. The same behaviour applied to measured moments with 67 \% and 45 \%. As a consequence, the motion deflected to the lower levels of the lumbar spine and the lower discs had to resist an increase in loading. Conclusions Higher values of ligament stiffness over all lumbar levels could lead to a shift of the loading and the motion between segments to the lower lumbar levels. This could lead to an increased risk for the lower lumbar parts.}, language = {en} } @article{WeberDendorferGrifkaetal., author = {Weber, Tim A. and Dendorfer, Sebastian and Grifka, Joachim and Verkerke, Gijsbertus Jacob and Renkawitz, Tobias}, title = {Does Computer-Assisted Femur First THR Improve Musculoskeletal Loading Conditions?}, series = {BioMed Research International}, volume = {2015}, journal = {BioMed Research International}, editor = {Takagi, Michiaki}, doi = {10.1155/2015/625317}, pages = {ID 625317}, abstract = {We have developed a novel, computer-assisted operation method for minimal-invasive total hip replacement (THR) following the concept of "femur first/combined anteversion," which incorporates various aspects of performing a functional optimization of the prosthetic stem and cup position (CAS FF). The purpose of this study is to assess whether the hip joint reaction forces and patient's gait parameters are being improved by CAS FF in relation to conventional THR (CON). We enrolled 60 patients (28 CAS FF/32 CON) and invited them for gait analysis at three time points (preoperatively, postop six months, and postop 12 months). Data retrieved from gait analysis was processed using patient-specific musculoskeletal models. The target parameters were hip reaction force magnitude (hrf), symmetries, and orientation with respect to the cup. Hrf in the CAS FF group were closer to a young healthy normal. Phase-shift symmetry showed an increase in the CAS FF group. Hrf orientation in the CAS FF group was closer to optimum, though no edge or rim-loading occurred in the CON group as well. The CAS FF group showed an improved hrf orientation in an early stage and a trend to an improved long-term outcome.}, subject = {H{\"u}ftgelenkprothese}, language = {en} } @article{WeberMerleNawabietal., author = {Weber, Markus and Merle, Christian and Nawabi, Danyal H. and Dendorfer, Sebastian and Grifka, Joachim and Renkawitz, Tobias}, title = {Inaccurate offset restoration in total hip arthroplasty results in reduced range of motion}, series = {Scientific Reports}, volume = {10}, journal = {Scientific Reports}, number = {13208}, publisher = {Nature}, doi = {10.1038/s41598-020-70059-1}, pages = {9}, abstract = {Offset restoration in total hip arthroplasty (THA) is associated with postoperative range of motion (ROM) and gait kinematics. We aimed to research into the impact of high offset (HO) and standard stems on postoperative ROM. 121 patients received cementless THA through a minimally-invasive anterolateral approach. A 360° hip ROM analysis software calculated impingement-free hip movement based on postoperative 3D-CTs compared to ROM values necessary for activities of daily living (ADL). The same model was then run a second time after changing the stem geometry between standard and HO configuration with the implants in the same position. HO stems showed higher ROM for all directions between 4.6 and 8.9° (p < 0.001) compared with standard stems but with high interindividual variability. In the subgroup with HO stems for intraoperative offset restoration, the increase in ROM was even higher for all ROM directions with values between 6.1 and 14.4° (p < 0.001) compared to offset underrestoration with standard stems. Avoiding offset underrestoration resulted in a higher amount of patients of over 20\% for each ROM direction that fulfilled the criteria for ADL (p < 0.001). In contrast, in patients with standard stems for offset restoration ROM did increase but not clinically relevant by offset overcorrection for all directions between 3.1 and 6.1° (p < 0.001). Offset overcorrection by replacing standard with HO stems improved ROM for ADL in a low number of patients below 10\% (p > 0.03). Patient-individual restoration of offset is crucial for free ROM in THA. Both over and underrestoration of offset should be avoided.}, language = {en} } @article{ScheerKubowitschDendorferetal., author = {Scheer, Clara and Kubowitsch, Simone and Dendorfer, Sebastian and Jansen, Petra}, title = {Happy Enough to Relax? How Positive and Negative Emotions Activate Different Muscular Regions in the Back - an Explorative Study}, series = {Frontiers in Psychology}, volume = {Volume 12}, journal = {Frontiers in Psychology}, number = {May 2021}, publisher = {Frontiers Media}, issn = {1664-1078}, doi = {10.3389/fpsyg.2021.511746}, abstract = {Embodiment theories have proposed a reciprocal relationship between emotional state and bodily reactions. Besides large body postures, recent studies have found emotions to affect rather subtle bodily expressions, such as slumped or upright sitting posture. This study investigated back muscle activity as an indication of an effect of positive and negative emotions on the sitting position. The electromyography (EMG) activity of six back muscles was recorded in 31 healthy subjects during exposure to positive and negative affective pictures. A resting period was used as a control condition. Increased muscle activity patterns in the back were found during the exposure to negative emotional stimuli, which was mainly measured in the lumbar and thorax regions. The positive emotion condition caused no elevated activity. The findings show that negative emotions lead to increased differential muscle activity in the back and thus corroborate those of previous research that emotion affects subtle bodily expressions.}, language = {en} } @incollection{GreinerLauer, author = {Greiner, Nina and Lauer, Norina}, title = {Informierte Einwilligung bei Aphasie}, series = {Digitale Technik f{\"u}r ambulante Pflege und Therapie: Herausforderungen, L{\"o}sungen, Anwendungen und Forschungsperspektiven}, booktitle = {Digitale Technik f{\"u}r ambulante Pflege und Therapie: Herausforderungen, L{\"o}sungen, Anwendungen und Forschungsperspektiven}, editor = {Weber, Karsten and Haug, Sonja and Lauer, Norina and Meussling-Sentpali, Annette and Mohr, Christa and Pfingsten, Andrea and Raptis, Georgios and Bahr, Gudrun}, edition = {1. Aufl.}, publisher = {transcript}, address = {Bielefeld}, isbn = {978-3-8394-6235-5}, doi = {10.14361/9783839462355-007}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-55107}, publisher = {Ostbayerische Technische Hochschule Regensburg}, pages = {137 -- 154}, abstract = {Nach einer Einf{\"u}hrung in die Grundlagen der informierten Einwilligung werden Empfehlungen zur Durchf{\"u}hrung zusammengefasst und Besonderheiten im Hinblick auf die Gestaltung des Einwilligungsprozesses bei Personen mit Aphasie herausgearbeitet. Zuletzt wird das aphasiefreundliche Vorgehen im Projekt DeinHaus 4.0 Oberpfalz kurz skizziert.}, subject = {Informed consent}, language = {de} } @article{BraunKunklerKellner, author = {Braun, Maximilian and Kunkler, Jan and Kellner, Florian}, title = {Towards Sustainable Cities: Utilizing Floating Car Data to Support Location-Based Road Network Performance Measurements}, series = {Sustainability}, volume = {12}, journal = {Sustainability}, number = {19}, publisher = {MDPI}, doi = {10.3390/su12198145}, abstract = {Road network performance (RNP) is a key element for urban sustainability as it has a significant impact on economy, environment, and society. Poor RNP can lead to traffic congestion, which can lead to higher transportation costs, more pollution and health issues regarding the urban population. To evaluate the effects of the RNP, the involved stakeholders need a real-world data base to work with. This paper develops a data collection approach to enable location-based RNP analysis using publicly available traffic information. Therefore, we use reachable range requests implemented by navigation service providers to retrieve travel times, travel speeds, and traffic conditions. To demonstrate the practicability of the proposed methodology, a comparison of four German cities is made, considering the network characteristics with respect to detours, infrastructure, and traffic congestion. The results are combined with cost rates to compare the economical dimension of sustainability of the chosen cities. Our results show that digitization eases the assessment of traffic data and that a combination of several indicators must be considered depending on the relevant sustainability dimension decisions are made from.}, language = {en} } @article{KunklerBraunKellner, author = {Kunkler, Jan and Braun, Maximilian and Kellner, Florian}, title = {Speed Limit Induced CO2 Reduction on Motorways: Enhancing Discussion Transparency through Data Enrichment of Road Networks}, series = {Sustainability}, volume = {13}, journal = {Sustainability}, number = {1}, publisher = {MDPI}, doi = {10.3390/su13010395}, abstract = {Considering climate change, recent political debates often focus on measures to reduce CO2 emissions. One key component is the reduction of emissions produced by motorized vehicles. Since the amount of emission directly correlates to the velocity of a vehicle via energy consumption factors, a general speed limit is often proposed. This article presents a methodology to combine openly available topology data of road networks from OpenStreetMap (OSM) with pay-per-use API traffic data from TomTom to evaluate such measures transparently by analyzing historical real-world circumstances. From our exemplary case study of the German motorway network, we derive that most parts of the motorway network on average do not reach their maximum allowed speed throughout the day due to traffic, construction sites and general road utilization by network participants. Nonetheless our findings prove that the introduction of a speed limit of 120 km per hour on the German autobahn would restrict 50.74\% of network flow kilometers for a CO2 reduction of 7.43\% compared to the unrestricted state.}, language = {en} } @article{LienlandZeng, author = {Lienland, Bernhard and Zeng, Li}, title = {A Review and Comparison of Genetic Algorithms for the 0-1 Multidimensional Knapsack Problem}, series = {International Journal of Operations Research and Information Systems (IJORIS)}, volume = {6}, journal = {International Journal of Operations Research and Information Systems (IJORIS)}, number = {2}, publisher = {IGI Global}, issn = {1947-9328}, doi = {10.4018/ijoris.2015040102}, pages = {11}, abstract = {The 0-1 multidimensional knapsack problem (MKP) is a well-known combinatorial optimization problem with several real-life applications, for example, in project selection. Genetic algorithms (GA) are effective heuristics for solving the 0-1 MKP. Multiple individual GAs with specific characteristics have been proposed in literature. However, so far, these approaches have only been partially compared in multiple studies with unequal conditions. Therefore, to identify the "best" genetic algorithm, this article reviews and compares 11 existing GAs. The authors' tests provide detailed information on the GAs themselves as well as their performance. The authors validated fitness values and required computation times in varying problem types and environments. Results demonstrate the superiority of one GA.}, language = {en} } @article{KellnerOttoBrabaender, author = {Kellner, Florian and Otto, Andreas and Brab{\"a}nder, Christian}, title = {Bringing infrastructure into pricing in road freight transportation - A measuring concept based on navigation service data}, series = {Transportation Research Procedia}, volume = {25}, journal = {Transportation Research Procedia}, publisher = {Elsevier}, doi = {10.1016/j.trpro.2017.05.458}, pages = {794 -- 805}, abstract = {Differences in road infrastructure, such as capacity, congestion, speed limits affect the productivity and the costs of short-distance freight operations. This article introduces a novel methodology that is based on navigation service data to measure the effects in terms of cost per kilometer using navigation and shipment data. The methodology is applied to five terminals of a forwarding cooperation and has been able to document significant differences in cost per kilometer across the terminals. The research results can be used by logistics service providers to better understand how productivity and thus profitability is affected by the quality of the transportation infrastructure in the particular areas they operate in. Furthermore, the insights will help these companies for better, i.e. cost-based pricing and will allow to document why and where prices need to be adapted.}, language = {en} } @article{Kellner, author = {Kellner, Florian}, title = {Exploring the impact of traffic congestion on CO2 emissions in freight distribution networks}, series = {Logistics Research}, volume = {9}, journal = {Logistics Research}, publisher = {Springer Nature}, doi = {10.1007/s12159-016-0148-5}, abstract = {This research quantifies the impact that regular road traffic congestion has on the CO2 emissions of a real-world distribution network, and it studies the consequences when the number of distribution centers changes. For this purpose, this study makes use of a network model allowing for a detailed representation of all relevant transport operations, including production flows between factories and distribution centers, line haul shipments between distribution centers and customers, and round/delivery trips between transshipment points and retailer locations for the last mile. The processed trip and traffic information does not rely on standard traffic data collection approaches, such as interviews, in situ technologies, or floating car data, but the road traffic data are retrieved from an online navigation service, such as Bing Maps, Google Maps, Inrix, Here, and TomTom. This study proves that online navigation services may considerably contribute to future research projects analyzing CO2 sensitivities and greenhouse gas cutting opportunities in logistics networks.}, language = {en} } @article{KraftQuaysonKellner, author = {Kraft, Sarah Katharina and Quayson, Matthew and Kellner, Florian}, title = {Assessing the German Act on Corporate Due Diligence Obligations in Supply Chains: a perspective from the smallholder cocoa farmer}, series = {Frontiers in Sustainability}, volume = {5}, journal = {Frontiers in Sustainability}, publisher = {frontiers}, doi = {10.3389/frsus.2024.1376619}, abstract = {This research examines the potential outputs, outcomes, and impacts of the German Act on Corporate Due Diligence Obligations in Supply Chains (LkSG) on the smallholder cocoa farmers in West Africa. The study primarily relies on a literature review and an impact pathway to conduct a systematic analysis to identify the potential effects of the LkSG on smallholder cocoa farmers. The findings indicate that some, but not all of the risks addressed by the LkSG align with those faced by smallholder cocoa farmers and their families. Additionally, the research also reveals weaknesses, particularly in managing environmental risks, which the LkSG does not adequately cover. Our findings show that in the short- and medium-term, the LkSG has no potential effects on smallholder cocoa farmers. Furthermore, the potential positive impacts of the law on smallholder cocoa farmers will take a long time to realize, as the LkSG considers primarily tier-1 suppliers. Companies in Germany might reassess their supply chains to strive for an LkSG-risk-free supply chain, which could in the long term have sustained impacts on smallholder cocoa farmers. However, we recommend a comprehensive risk analysis of the cocoa supply chain to enhance the human rights of cocoa farmers.}, language = {en} } @article{KraftKellner, author = {Kraft, Sarah Katharina and Kellner, Florian}, title = {Can Blockchain Be a Basis to Ensure Transparency in an Agricultural Supply Chain?}, series = {Sustainability}, volume = {14}, journal = {Sustainability}, number = {13}, publisher = {MDPI}, doi = {10.3390/su14138044}, abstract = {Many supply chains within developing countries lack transparency and are fraught with fraud, corruption, and a substantial number of intermediaries. For several decades, the cocoa sector has faced multiple social, economic, and environmental challenges, some of which include the issue of child labor and very low incomes for farmers, leading to poor living conditions. Blockchain technology has a high potential to reduce—or completely eradicate—some of these hurdles. In this article, we present a blockchain-based solution based on the open-source framework Hyperledger Fabric for the cocoa supply chain to promote transparency and reduce fraud. In doing so, we explicitly describe how farmers can be directly integrated into the whole blockchain solution considering the limited infrastructure, knowledge, and technologies available to them. Since about 70\% of all cocoa worldwide is produced in West Africa, this case study uses the cocoa sector in Ghana as an example.}, language = {en} } @article{KunklerKellner, author = {Kunkler, Jan and Kellner, Florian}, title = {Sustainable City Evaluation Using the Database for Estimation of Road Network Performance}, series = {Sustainability}, volume = {15}, journal = {Sustainability}, number = {1}, publisher = {MDPI}, doi = {10.3390/su15010733}, abstract = {This article introduces the Database for Estimation of Road Network Performance (DERNP) to enable wide-scale estimation of relevant Road Network Performance (RNP) factors for major German cities. The methodology behind DERNP is based on a randomized route sampling procedure that utilizes the Worldwide Harmonized Light Vehicles Test Procedure (WLTP) in combination with the tile-based HERE Maps Traffic API v7 and a digital elevation model provided by the European Union's Earth Observation Programme Copernicus to generate a large set of independent and realistic routes throughout OpenStreetMap road networks. By evaluating these routes using the PHEMLight5 framework, a comprehensive list of RNP parameters is estimated and translated into polynomial regression models for general usage. The applicability of these estimations is demonstrated based on a case study of four major German cities. This case study considers network characteristics in terms of detours, infrastructure, traffic congestion, fuel consumption, and CO2 emissions. Our results show that DERNP and its underlying randomized route sampling methodology overcomes major limitations of previous wide-scale RNP approaches, enabling efficient, easy-to-use, and region-specific RNP comparisons.}, language = {en} } @article{PhilippdeSomerFoltanetal., author = {Philipp, Alois and de Somer, Filip and Foltan, Maik and Bredthauer, Andre and Krenkel, Lars and Zeman, Florian and Lehle, Karla}, title = {Life span of different extracorporeal membrane systems for severe respiratory failure in the clinical practice}, series = {PLOS ONE}, volume = {13}, journal = {PLOS ONE}, number = {6}, publisher = {PLOS}, doi = {10.1371/journal.pone.0198392}, pages = {1 -- 10}, abstract = {Over the past decade, veno-venous extracorporeal membrane oxygenation (vvECMO) has been increasingly utilized in respiratory failure in patients. This study presents our institution´s experience focusing on the life span of ECMO systems reflecting the performance of a particular system. A retrospective review of our ECMO database identified 461 adult patients undergoing vvECMO (2010-2017). Patients that required more than one system and survived the first exchange >24 hours (n = 139) were included. Life span until the first exchange and exchange criteria were analyzed for all systems (PLS, Cardiohelp HLS-set, both Maquet Cardiopulmonary, Rastatt, Germany; Deltastream/Hilite7000LT, iLA-activve, Xenios/NovaLung, Heilbronn, Germany; ECC.O5, LivaNova, Mirandola, Italy). At our ECMO center, the frequency of a system exchange was 30\%. The median (IQR) life span was 9 (6-12) days. There was no difference regarding the different systems (p = 0.145 and p = 0.108, respectively). However, the Deltastream systems were exchanged more frequently due to elective technical complications (e. g. worsened gas transfer, development of coagulation disorder, increased bleedings complications) compared to the other exchanged systems (p = 0.013). In summary, the used ECMO systems are safe and effective for acute respiratory failure. There is no evidence for the usage of a specific system. Only the increased predictability of an imminent exchange preferred the usage of a Deltastream system. However, the decision to use a particular system should not depend solely on the possible criteria for an exchange.}, language = {en} } @article{DiermeierSindersbergerKrenkeletal., author = {Diermeier, Andreas and Sindersberger, Dirk and Krenkel, Lars and Rosell, X. C. and Monkman, Gareth J.}, title = {Controllable Magnetoactive Polymer Conduit}, series = {The Open Mechanical Engineering Journal}, volume = {12}, journal = {The Open Mechanical Engineering Journal}, number = {1}, publisher = {Bentham}, pages = {192 -- 200}, abstract = {Objective: Magneto-active Polymers (MAP) are smart materials whose mechanical characteristics, such as elastic and shear moduli, may be controllable by means of an externally applied magnetic field. Methods: Various additives may be used to influence the characteristics of the polymer matrix whilst a suspension of soft and/or hard magnetic particles determine the magnetic properties of the composite. Both pre-cure and post-cure magnetization is possible. Results: A range of control strategies have been investigated for evaluation of the system using fluids of differing kinematic viscosity. Conclusion: Depending on the degree of magnetic field homogeneity, magneto-deformation and magnetostriction contribute to MAP actuation. This paper presents a novel application in the form of a peristaltic MAP tube system, applicable to flow control and pumping of hemorheological fluids in blood circulatory systems for biomedical research purposes.}, language = {en} } @article{KoeckStrieglKrausetal., author = {K{\"o}ck, Hannah and Striegl, Birgit and Kraus, Annalena and Zborilova, Magdalena and Christiansen, Silke H. and Sch{\"a}fer, Nicole and Gr{\"a}ssel, Susanne and Hornberger, Helga}, title = {In Vitro Analysis of Human Cartilage Infiltrated by Hydrogels and Hydrogel-Encapsulated Chondrocytes}, series = {Bioengineering}, volume = {10}, journal = {Bioengineering}, publisher = {MDPI}, doi = {10.3390/bioengineering10070767}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-61235}, pages = {1 -- 21}, abstract = {Osteoarthritis (OA) is a degenerative joint disease causing loss of articular cartilage and structural damage in all joint tissues. Given the limited regenerative capacity of articular cartilage, methods to support the native structural properties of articular cartilage are highly anticipated. The aim of this study was to infiltrate zwitterionic monomer solutions into human OA-cartilage explants to replace lost proteoglycans. The study included polymerization and deposition of methacryloyloxyethyl-phosphorylcholine- and a novel sulfobetaine-methacrylate-based monomer solution within ex vivo human OA-cartilage explants and the encapsulation of isolated chondrocytes within hydrogels and the corresponding effects on chondrocyte viability. The results demonstrated that zwitterionic cartilage-hydrogel networks are formed by infiltration. In general, cytotoxic effects of the monomer solutions were observed, as was a time-dependent infiltration behavior into the tissue accompanied by increasing cell death and penetration depth. The successful deposition of zwitterionic hydrogels within OA cartilage identifies the infiltration method as a potential future therapeutic option for the repair/replacement of OA-cartilage extracellular suprastructure. Due to the toxic effects of the monomer solutions, the focus should be on sealing the OA-cartilage surface, instead of complete infiltration. An alternative treatment option for focal cartilage defects could be the usage of monomer solutions, especially the novel generated sulfobetaine-methacrylate-based monomer solution, as bionic for cell-based 3D bioprintable hydrogels.}, language = {en} } @article{MuellerHornberger, author = {M{\"u}ller, Wolf-Dieter and Hornberger, Helga}, title = {The Influence of MgH2 on the Assessment of Electrochemical Data to Predict the Degradation Rate of Mg and Mg Alloys}, series = {International Journal of Molecular Science}, volume = {15}, journal = {International Journal of Molecular Science}, doi = {10.3390/ijms150711456}, pages = {11456 -- 11472}, abstract = {Mg and Mg alloys are becoming more and more of interest for several applications. In the case of biomaterial applications, a special interest exists due to the fact that a predictable degradation should be given. Various investigations were made to characterize and predict the corrosion behavior in vitro and in vivo. Mostly, the simple oxidation of Mg to Mg2+ ions connected with adequate hydrogen development is assumed, and the negative difference effect (NDE) is attributed to various mechanisms and electrochemical results. The aim of this paper is to compare the different views on the corrosion pathway of Mg or Mg alloys and to present a neglected pathway based on thermodynamic data as a guideline for possible reactions combined with experimental observations of a delay of visible hydrogen evolution during cyclic voltammetry. Various reaction pathways are considered and discussed to explain these results, like the stability of the Mg+ intermediate state, the stability of MgH2 and the role of hydrogen overpotential. Finally, the impact of MgH2 formation is shown as an appropriate base for the prediction of the degradation behavior and calculation of the corrosion rate of Mg and Mg alloys.}, language = {en} } @article{HornbergerStrieglTrahanofskyetal., author = {Hornberger, Helga and Striegl, Birgit and Trahanofsky, M. and Kneissl, F. and Kronseder, Matthias}, title = {Degradation and bioactivity studies of Mg membranes for dental surgery}, series = {Materials Letter X}, volume = {2}, journal = {Materials Letter X}, number = {June}, publisher = {Elsevier}, doi = {10.1016/j.mlblux.2019.100007}, pages = {1 -- 5}, abstract = {Bioresorbable materials are under investigation due to their promising properties for applications as implant material. This study is about the degradation and bioactivity behaviour of magnesium foils, which allegorize dental membranes. The degradation behaviour including pitting corrosion during immersion tests can be precisely observed using micro-computed tomography. Using the bioactivity test according to Kokubo, it is shown that magnesium has strong Ca-phosphate layer formation correlated with high degradation. Therefore, magnesium foils appear to hold a great potential for bone implant application.}, language = {en} } @article{SteinhauserRaptis, author = {Steinhauser, Stefanie and Raptis, Georgios}, title = {Design propositions for nudging in healthcare: Adoption of national electronic health recordsystems}, series = {Digital Health}, volume = {9}, journal = {Digital Health}, publisher = {Sage}, issn = {2055-2076}, doi = {10.1177/20552076231181208}, pages = {1 -- 12}, abstract = {Objectives: Electronic health records (EHRs) are considered important for improving efficiency and reducing costs of ahealthcare system. However, the adoption of EHR systems differs among countries and so does the way the decision to par-ticipate in EHRs is presented. Nudging is a concept that deals with influencing human behaviour within the research streamof behavioural economics. In this paper, we focus on the effects of the choice architecture on the decision for the adoption ofnational EHRs. Our study aims to link influences on human behaviour through nudging with the adoption of EHRs to inves-tigate how choice architects can facilitate the adoption of national information systems. Methods: We employ a qualitative explorative research design, namely the case study method. Using theoretical sampling,we selected four cases (i.e., countries) for our study: Estonia, Austria, the Netherlands, and Germany. We collected and ana-lyzed data from various primary and secondary sources: ethnographic observation, interviews, scientific papers, homepages,press releases, newspaper articles, technical specifications, publications from governmental bodies, and formal studies. Results: The findings from our European case studies show that designing for EHR adoption should encompass choice archi-tecture elements (i.e., defaults), technical elements (i.e., choice granularity and access transparency), and institutional ele-ments (i.e., regulations for data protection, information campaigns, and financial incentives) in combination. Conclusions: Our findings provide insights on the design of the adoption environments of large-scale, national EHR systems.Future research could estimate the magnitude of effects of the determinants.}, language = {en} } @article{TauwaldMichelBrandtetal., author = {Tauwald, Sandra Melina and Michel, Johanna and Brandt, Marie and Vielsmeier, Veronika and Stemmer, Christian and Krenkel, Lars}, title = {Experimental studies and mathematical modeling of the viscoelastic rheology of tracheobronchial mucus from respiratory healthy patients}, series = {Multidisciplinary Respiratory Medicine}, volume = {18}, journal = {Multidisciplinary Respiratory Medicine}, number = {1}, publisher = {PAGEPress}, address = {Pavia, Italy}, issn = {2049-6958}, doi = {10.4081/mrm.2023.923}, pages = {12}, abstract = {BACKGROUND: Tracheobronchial mucus plays a crucial role in pulmonary function by providing protection against inhaled pathogens. Due to its composition of water, mucins, and other biomolecules, it has a complex viscoelastic rheological behavior. This interplay of both viscous and elastic properties has not been fully described yet. In this study, we characterize the rheology of human mucus using oscillatory and transient tests. Based on the transient tests, we describe the material behavior of mucus under stress and strain loading by mathematical models. METHODS: Mucus samples were collected from clinically used endotracheal tubes. For rheological characterization, oscillatory amplitude-sweep and frequency-sweep tests, and transient creep-recovery and stress-relaxation tests were performed. The results of the transient test were approximated using the Burgers model, the Weibull distribution, and the six-element Maxwell model. The three-dimensional microstructure of the tracheobronchial mucus was visualized using scanning electron microscope imaging. RESULTS: Amplitude-sweep tests showed storage moduli ranging from 0.1 Pa to 10000 Pa and a median critical strain of 4 \%. In frequency-sweep tests, storage and loss moduli increased with frequency, with the median of the storage modulus ranging from 10 Pa to 30 Pa, and the median of the loss modulus from 5 Pa to 14 Pa. The Burgers model approximates the viscoelastic behavior of tracheobronchial mucus during a constant load of stress appropriately (R2 of 0.99), and the Weibull distribution is suitable to predict the recovery of the sample after the removal of this stress (R2 of 0.99). The approximation of the stress-relaxation test data by a six-element Maxwell model shows a larger fit error (R2 of 0.91). CONCLUSIONS: This study provides a detailed description of all process steps of characterizing the rheology of tracheobronchial mucus, including sample collection, microstructure visualization, and rheological investigation. Based on this characterization, we provide mathematical models of the rheological behavior of tracheobronchial mucus. These can now be used to simulate mucus flow in the respiratory system through numerical approaches.}, language = {en} } @article{LooNagarajuPathivadaetal., author = {Loo, Xuyan and Nagaraju, Bhavana and Pathivada, Sai and Bartsch, Alexander and Schratzenstaller, Thomas and Sattler, Robert and Monkman, Gareth J.}, title = {Electrical properties of bisphenol-A-free magnetoactive borosilicate polymers}, series = {AIP Advances}, volume = {14}, journal = {AIP Advances}, number = {5}, publisher = {AIP Publishing}, issn = {2158-3226}, doi = {10.1063/5.0203017}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-72936}, abstract = {The recent REACH regulations require the elimination of bisphenol-A and titanium dioxide from commercially available boron-based polymers. This has led to changes in some of the mechanical characteristics, which strongly influence the properties of magnetoactive borosilicate polymers. This work delivers results on the electrical properties and discusses some implications for future research using bisphenol-A and titanium-dioxide-free substitutes.}, language = {en} } @article{EigenbergerFelthausSchratzenstalleretal., author = {Eigenberger, Andreas and Felthaus, Oliver and Schratzenstaller, Thomas and Haerteis, Silke and Utpatel, Kirsten and Prantl, Lukas}, title = {The Effects of Shear Force-Based Processing of Lipoaspirates on White Adipose Tissue and the Differentiation Potential of Adipose Derived Stem Cells}, series = {cells}, volume = {11}, journal = {cells}, number = {16}, publisher = {MDPI}, address = {Basel}, doi = {10.3390/cells11162543}, pages = {13}, abstract = {Autologous lipotransfer is a promising method for tissue regeneration, because white adipose tissue contains a heterogeneous cell population, including mesenchymal stem cells, endothelial cells, immune cells, and adipocytes. In order to improve the outcome, adipose tissue can be processed before application. In this study, we investigated changes caused by mechanical processing. Lipoaspirates were processed using sedimentation, first-time centrifugation, shear-force homogenization, and second-time centrifugation. The average adipocyte size, stromal vascular cell count, and adipocyte depot size were examined histologically at every processing step. In addition, the adipose derived stem cells (ADSCs) were isolated and differentiated osteogenically and adipogenically. While homogenization causes a disruption of adipocyte depots, the shape of the remaining adipocytes is not changed. On average, these adipocytes are smaller than the depot adipocytes, they are surrounded by the ECM, and therefore mechanically more stable. The volume loss of adipocyte depots leads to a significant enrichment of stromal vascular cells such as ADSCs. However, the mechanical processing does not change the potential of the ADSCs to differentiate adipogenically or steogenically. It thus appears that mechanically processed lipoaspirates are promising for the reparation of even mechanically stressed tissue as that found in nasolabial folds. The changes resulting from the processing correspond more to a filtration of mechanically less stable components than to a manipulation of the tissue.}, language = {en} } @article{WiesentSchultheissSchmidetal., author = {Wiesent, Lisa and Schultheiss, Ulrich and Schmid, Christof and Schratzenstaller, Thomas and Nonn, Aida}, title = {Experimentally validated simulation of coronary stents considering different dogboning ratios and asymmetric stent positioning}, series = {PlOS One}, volume = {14}, journal = {PlOS One}, number = {10}, publisher = {PLOS}, doi = {10.1371/journal.pone.0224026}, pages = {1 -- 25}, abstract = {In-stent restenosis remains a major problem of arteriosclerosis treatment by stenting. Expansion-optimized stents could reduce this problem. With numerical simulations, stent designs/ expansion behaviours can be effectively analyzed. For reasons of efficiency, simplified models of balloon-expandable stents are often used, but their accuracy must be challenged due to insufficient experimental validation. In this work, a realistic stent life-cycle simulation has been performed including balloon folding, stent crimping and free expansion of the balloon-stent-system. The successful simulation and validation of two stent designs with homogenous and heterogeneous stent stiffness and an asymmetrically positioned stent on the balloon catheter confirm the universal applicability of the simulation approach. Dogboning ratio, as well as the final dimensions of the folded balloon, the crimped and expanded stent, correspond well to the experimental dimensions with only slight deviations. In contrast to the detailed stent life-cycle simulation, a displacement-controlled simulation can not predict the transient stent expansion, but is suitable to reproduce the final expanded stent shape and the associated stress states. The detailed stent life-cycle simulation is thus essential for stent expansion analysis/optimization, whereas for reasons of computational efficiency, the displacement-controlled approach can be considered in the context of pure stress analysis.}, subject = {Stent}, language = {en} } @article{GeithSwidergalHochholdingeretal., author = {Geith, Markus A. and Swidergal, Krzysztof and Hochholdinger, Bernd and Schratzenstaller, Thomas and Wagner, Marcus and Holzapfel, Gerhard A.}, title = {On the importance of modeling balloon folding, pleating, and stent crimping: An FE study comparing experimental inflation tests}, series = {International Journal for Numerical Methods in Biomedical Engineering}, volume = {35}, journal = {International Journal for Numerical Methods in Biomedical Engineering}, number = {11}, publisher = {Wiley}, doi = {10.1002/cnm.3249}, abstract = {Finite element (FE)-based studies of preoperative processes such as folding,pleating, and stent crimping with a comparison with experimental inflation tests are not yet available. Therefore, a novel workflow is presented in which residual stresses of balloon folding and pleating, as well as stent crimping, and the geometries of all contact partners were ultimately implemented in an FE code to simulate stent expansion by using an implicit solver. The numerical results demonstrate that the incorporation of residual stresses and strains experienced during the production step significantly increased the accuracy of the subsequent simulations, especially of the stent expansion model. During the preoperative processes, stresses inside the membrane and the stent material also reached a rather high level. Hence, there can be no presumption that balloon catheters or stents are undamaged before the actual surgery. The implementation of the realistic geometry, in particular the balloon tapers, and the blades of the process devices improved the simulation of the expansion mech-anisms, such as dogboning, concave bending, or overexpansion of stent cells. This study shows that implicit solvers are able to precisely simulate the mentioned preoperative processes and the stent expansion procedure without a preceding manipulation of the simulation time or physical mass.}, subject = {Stent}, language = {en} } @article{GeithSommerSchratzenstalleretal., author = {Geith, Markus A. and Sommer, Gerhard and Schratzenstaller, Thomas and Holzapfel, Gerhard A.}, title = {Biomechanical and structural quantification of vascular damage: A unique investigation of stent implantation}, series = {Artery Research}, volume = {20}, journal = {Artery Research}, number = {Issue C}, doi = {10.1016/j.artres.2017.10.025}, pages = {50}, language = {en} } @article{ZentgrafNuetzelMuehlbaueretal., author = {Zentgraf, Jan and N{\"u}tzel, Florian and M{\"u}hlbauer, Nico and Schultheiss, Ulrich and Grad, Marius and Schratzenstaller, Thomas}, title = {Surface Treatment of Additively Manufactured Polyetheretherketone (PEEK) by Centrifugal Disc Finishing Process: Identification of the Key Parameters}, series = {Polymers}, volume = {16}, journal = {Polymers}, publisher = {MDPI}, address = {Basel}, issn = {2073-4360}, doi = {10.3390/polym16162348}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-73959}, abstract = {Polyetheretherketone is a promising material for implants due to its good mechanical properties and excellent biocompatibility. Its accessibility to a wide range of applications is facilitated by the ability to process it with an easy-to-use manufacturing process such as fused filament fabrication. The elimination of disadvantages associated with the manufacturing process, such as a poor surface quality, is a main challenge to deal with. As part of the mass finishing process, centrifugal disc finishing has demonstrated good results in surface optimization, making it a promising candidate for the post-processing of additively manufactured parts. The objective of this study is to identify the key parameters of the centrifugal disc finishing process on the waviness of additively manufactured PEEK specimens, which has not been investigated previously. The waviness of the specimen was investigated by means of confocal laser scanning microscopy (CLSM), while weight loss was additionally tracked. Six parameters were investigated: type, amount and speed of media, use of compound, amount of water and time. Type of media, time and speed were found to significantly influence waviness reduction and weight loss. Surface electron microscopy images demonstrated the additional effects of deburring and corner rounding. Results on previous studies with specimens made of metal showed similar results. Further investigation is required to optimize waviness reduction and polish parts in a second post-processing step.}, language = {en} } @article{WiesentSchultheissLullaetal., author = {Wiesent, Lisa and Schultheiß, Ulrich and Lulla, Philipp and Noster, Ulf and Schratzenstaller, Thomas and Schmid, Christof and Nonn, Aida and Spear, Ashley}, title = {Computational analysis of the effects of geometric irregularities and post-processing steps on the mechanical behavior of additively manufactured 316L stainless steel stents}, series = {PLoS ONE}, volume = {15}, journal = {PLoS ONE}, number = {12}, publisher = {PLOS}, doi = {10.1371/journal.pone.0244463}, pages = {1 -- 30}, abstract = {Advances in additive manufacturing enable the production of tailored lattice structures and thus, in principle, coronary stents. This study investigates the effects of process-related irregularities, heat and surface treatment on the morphology, mechanical response, and expansion behavior of 316L stainless steel stents produced by laser powder bed fusion and provides a methodological approach for their numerical evaluation. A combined experimental and computational framework is used, based on both actual and computationally reconstructed laser powder bed fused stents. Process-related morphological deviations between the as-designed and actual laser powder bed fused stents were observed, resulting in a diameter increase by a factor of 2-2.6 for the stents without surface treatment and 1.3-2 for the electropolished stent compared to the as-designed stent. Thus, due to the increased geometrically induced stiffness, the laser powder bed fused stents in the as-built (7.11 ± 0.63 N) or the heat treated condition (5.87 ± 0.49 N) showed increased radial forces when compressed between two plates. After electropolishing, the heat treated stents exhibited radial forces (2.38 ± 0.23 N) comparable to conventional metallic stents. The laser powder bed fused stents were further affected by the size effect, resulting in a reduced yield strength by 41\% in the as-built and by 59\% in the heat treated condition compared to the bulk material obtained from tensile tests. The presented numerical approach was successful in predicting the macroscopic mechanical response of the stents under compression. During deformation, increased stiffness and local stress concentration were observed within the laser powder bed fused stents. Subsequent numerical expansion analysis of the derived stent models within a previously verified numerical model of stent expansion showed that electropolished and heat treated laser powder bed fused stents can exhibit comparable expansion behavior to conventional stents. The findings from this work motivate future experimental/numerical studies to quantify threshold values of critical geometric irregularities, which could be used to establish design guidelines for laser powder bed fused stents/lattice structures.}, subject = {Koronarendoprothese}, language = {en} } @article{GeithEckmannHaspingeretal., author = {Geith, Markus A. and Eckmann, Jakob D. and Haspinger, Daniel Ch. and Agrafiotis, Emmanouil and Maier, Dominik and Szabo, Patrick and Sommer, Gerhard and Schratzenstaller, Thomas and Holzapfel, Gerhard A.}, title = {Experimental and mathematical characterization of coronary polyamide-12 balloon catheter membranes}, series = {PLoS One}, volume = {15}, journal = {PLoS One}, number = {6}, publisher = {PLOS}, doi = {10.1371/journal.pone.0234340}, pages = {1 -- 22}, abstract = {The experimental quantification and modeling of the multiaxial mechanical response of polymer membranes of coronary balloon catheters have not yet been carried out. Due to the lack of insights, it is not shown whether isotropic material models can describe the material response of balloon catheter membranes expanded with nominal or higher, supra-nominal pressures. Therefore, for the first time, specimens of commercial polyamide-12 balloon catheters membranes were investigated during uniaxial and biaxial loading scenarios. Furthermore, the influence of kinematic effects on the material response was observed by comparing results from quasi-static and dynamic biaxial extension tests. Novel clamping techniques are described, which allow to test even tiny specimens taken from the balloon membranes. The results of this study reveal the semi-compliant, nonlinear, and viscoelastic character of polyamide-12 balloon catheter membranes. Above nominal pressure, the membranes show a pronounced anisotropic mechanical behavior with a stiffer response in the circumferential direction. The anisotropic feature intensifies with an increasing strain-rate. A modified polynomial model was applied to represent the realistic mechanical response of the balloon catheter membranes during dynamic biaxial extension tests. This study also includes a compact set of constitutive model parameters for the use of the proposed model in future finite element analyses to perform more accurate simulations of expanding balloon catheters.}, language = {en} } @article{Goertler, author = {G{\"o}rtler, Michael}, title = {Politische Erwachsenenbildung und Zeit}, series = {Zeitschrift f{\"u}r Weiterbildungsforschung (ZfW)}, journal = {Zeitschrift f{\"u}r Weiterbildungsforschung (ZfW)}, number = {1}, publisher = {Springer}, organization = {Springer}, doi = {10.1007/s40955-016-0052-2}, pages = {9 -- 25}, abstract = {Der Beitrag fokussiert die Bedeutung von Zeit f{\"u}r die politische Erwachsenenbildung. Angesichts aktueller soziokultureller und sozio{\"o}konomischer Herausforderungen - besonders: der {\"O}konomisierung und Beschleunigung im Kontext von Bildung und Lernen - ergeben sich eine ganze Reihe von dr{\"a}ngenden Zeitfragen. Der Bedeutung von Zeit wird in der Erwachsenenbildung und der Politischen Bildung jedoch bisher wenig Aufmerksamkeit geschenkt. Aus diesem Grund wird diese Fragestellung im Beitrag vertieft. Erstens werden die Situation der politischen Erwachsenenbildung und zweitens der Forschungsstand untersucht. Ausgehend von den Befunden werden drittens drei Zug{\"a}nge herausgearbeitet, welche die Bedeutung von Zeit f{\"u}r die politische Erwachsenenbildung sichtbar machen: Politische Bildung als Prozess und Verz{\"o}gerung sowie Zeit als Gegenstand, um die Zeitlichkeit von Gesellschaft und Politik zu verstehen und zu beurteilen, um sich an der Gestaltung der Zeitstrukturen zu beteiligen. Der Beitrag endet mit einem Ausblick und offenen Fragen, die sich an die zeittheoretischen {\"U}berlegungen anschließen. The article focusses on the importance of time for the political adult education. Current socio-cultural and socio-economic challenges - in particular: the commodification and acceleration in the context of education and learning - results in a wide range of pressing time issues. However the adult education und the political education pay little attention to the importance of time. For this reason, this issue will be deepened in the article. First, the situation of the political adult education and secondly, the state of research are examined. On the base of the findings, three approaches are pointed out, which emphasize the importance of time for the political adult education: political education as a process and as a deceleration and also as a subject to understand and judge the temporality of politics and society as a necessary condition to participate in shaping the time structures. The paper ends with an outlook and open-ended questions, which adjoin the time theoretical considerations.}, language = {de} } @article{Goertler, author = {G{\"o}rtler, Michael}, title = {Soziale Arbeit, Zeit und Nachhaltigkeit : Zeitpolitische Perspektiven}, series = {ZPM - Zeitpolitisches Magazin}, volume = {19}, journal = {ZPM - Zeitpolitisches Magazin}, number = {40}, publisher = {DGfZP (Deutsche Gesellschaft f{\"u}r Zeitpolitik)}, issn = {2196-0356}, pages = {24 -- 26}, abstract = {In diesem Beitrag sollen in der gebotenen K{\"u}rze zeitpolitische Perspektiven auf die Bedeutung von Zeit und Nachhaltigkeit im Kontext der Sozialen Arbeit reflektiert werden. Daf{\"u}r werden die Begriffsfelder um Nachhaltigkeit und Zeit diskutiert und zeitpolitische Implikationen formuliert.}, language = {de} } @article{WalterSchwanzerSteineretal., author = {Walter, Stefanie and Schwanzer, Peter and Steiner, Carsten and Hagen, Gunter and Rabl, Hans-Peter and Dietrich, Markus and Moos, Ralf}, title = {Mixing Rules for an Exact Determination of the Dielectric Properties of Engine Soot Using the Microwave Cavity Perturbation Method and Its Application in Gasoline Particulate Filters}, series = {Sensors}, volume = {22}, journal = {Sensors}, number = {9}, publisher = {MDPI}, address = {Basel}, doi = {10.3390/s22093311}, pages = {1 -- 17}, abstract = {In recent years, particulate filters have become mandatory in almost all gasoline-powered vehicles to comply with emission standards regarding particulate number. In contrast to diesel applications, monitoring gasoline particulate filters (GPFs) by differential pressure sensors is challenging due to lower soot masses to be deposited in the GPFs. A different approach to determine the soot loading of GPFs is a radio frequency-based sensor (RF sensor). To facilitate sensor development, in previous work, a simulation model was created to determine the RF signal at arbitrary engine operating points. To ensure accuracy, the exact dielectric properties of the soot need to be known. This work has shown how small samples of soot-loaded filter are sufficient to determine the dielectric properties of soot itself using the microwave cavity perturbation method. For this purpose, mixing rules were determined through simulation and measurement, allowing the air and substrate fraction of the sample to be considered. Due to the different geometry of filter substrates compared to crushed soot samples, a different mixing rule had to be derived to calculate the effective filter properties required for the simulation model. The accuracy of the determined mixing rules and the underlying simulation model could be verified by comparative measurements on an engine test bench.}, language = {en} } @article{ThemaSternerLencketal., author = {Thema, Martin and Sterner, Michael and Lenck, Thorsten and G{\"o}tz, Philipp}, title = {Necessity and Impact of Power-to-gas on Energy Transition in Germany}, series = {Energy Procedia}, volume = {99}, journal = {Energy Procedia}, publisher = {Elsevier}, doi = {10.1016/j.egypro.2016.10.129}, pages = {392 -- 400}, abstract = {The present paper gives an outlook on a bandwidth of required installed power-to-gas capacity in the German power sector fed by 100\% renewable generation until 2050. Two scenarios were simulated to quantify cost effects of power-to-gas on the electricity system: once with, once without additional short-term flexibility options to a system using fossil natural gas as sole flexibility option instead. As a result, at latest in 2035, power-to-gas capacity expansion has to take place to reach required installed capacities of up to 89-134 GW in 2050. Application of power-to-gas as long-term flexibility leads to cost savings of up to 11,7-19 bn Euro enabling a fully renewable system in 2050.}, language = {en} } @article{ThemaWeidlichHoerletal., author = {Thema, Martin and Weidlich, Tobias and H{\"o}rl, Manuel and Bellack, Annett and M{\"o}rs, Friedemann and Hackl, Florian and Kohlmayer, Matthias and Gleich, Jasmin and Stabenau, Carsten and Trabold, Thomas and Neubert, Michael and Ortloff, Felix and Brotsack, Raimund and Schmack, Doris and Huber, Harald and Hafenbradl, Doris and Karl, J{\"u}rgen and Sterner, Michael}, title = {Biological CO2-Methanation: An Approach to Standardization}, series = {Energies}, volume = {12}, journal = {Energies}, number = {9}, publisher = {MDPI}, doi = {10.3390/en12091670}, pages = {1 -- 32}, abstract = {Power-to-Methane as one part of Power-to-Gas has been recognized globally as one of the key elements for the transition towards a sustainable energy system. While plants that produce methane catalytically have been in operation for a long time, biological methanation has just reached industrial pilot scale and near-term commercial application. The growing importance of the biological method is reflected by an increasing number of scientific articles describing novel approaches to improve this technology. However, these studies are difficult to compare because they lack a coherent nomenclature. In this article, we present a comprehensive set of parameters allowing the characterization and comparison of various biological methanation processes. To identify relevant parameters needed for a proper description of this technology, we summarized existing literature and defined system boundaries for Power-to-Methane process steps. On this basis, we derive system parameters providing information on the methanation system, its performance, the biology and cost aspects. As a result, three different standards are provided as a blueprint matrix for use in academia and industry applicable to both, biological and catalytic methanation. Hence, this review attempts to set the standards for a comprehensive description of biological and chemical methanation processes.}, language = {en} } @inproceedings{VitzthumClausHerrmann, author = {Vitzthum, Thorsten and Claus, Thorsten and Herrmann, Frank}, title = {Can Aggregate Production Planning (APP) be modified to be as good as Master Production Scheduling (MPS)}, series = {ACC Journal}, volume = {23}, booktitle = {ACC Journal}, number = {2}, doi = {10.15240/tul/004/2017-2-012}, pages = {155 -- 162}, abstract = {In diesem Beitrag wird anhand einer Fallstudie die Bedeutung der Hauptproduktionsprogrammplanung (HPPLAN) f{\"u}r die hierarchische Produktionsplanung herausgearbeitet werden. Dazu wird versucht das Ergebnis der aggregierten Gesamtplanung (AGGRPLAN) durch Ver{\"a}nderung einzelner Paramater so zu verbessern, dass es dem Ergebnis der HPPLAN entspricht. Im Rahmen der Untersuchungen konnten dabei Verbesserungen f{\"u}r einzelne Planungssituationen erzielt werden, eine generelle L{\"o}sung konnte jedoch nicht gefunden werden. Insbesondere der Einsatz eines geeigneten Kapazit{\"a}tsreduktionsfaktors in Verbindung mit der Ber{\"u}cksichtigung der Durchlaufzeit f{\"u}hrt zu einer Verbesserung der L{\"o}sung. Bei der Planung von mehr als einem Produkt ist allerdings schwierig einen geeigneten Kapazit{\"a}tsreduktionsfaktor zu finden, da dieser abh{\"a}ngig von der Nachfrage ist.}, subject = {Hierarchische Produktionsplanung}, language = {en} } @inproceedings{TrostTeichClausetal., author = {Trost, Marco and Teich, Enrico and Claus, Thorsten and Herrmann, Frank}, title = {Master Production Scheduling and the relevance of included social criteria}, series = {ACC Journal}, volume = {23}, booktitle = {ACC Journal}, number = {3}, doi = {10.15240/tul/004/2017-2-011}, pages = {146 -- 154}, abstract = {Folgender Beitrag untersucht die Notwendigkeit einer Ber{\"u}cksichtigung von Mitarbeiterauslastungen und davon abh{\"a}ngiger Bearbeitungszeiten in der Hauptproduktionsprogrammplanung. Zudem wird aufgezeigt, dass dieses Themengebiet aktuell eine Forschungsl{\"u}cke darstellt. Aus diesem Grund wird ein selbst entwickeltes lineares Optimierungsmodell f{\"u}r die Hauptproduktionsprogrammplanung vorgestellt, welches soziale Kriterien und eine geeignete Fallstudie enth{\"a}lt. Die Ergebnisse verdeutlichen, dass erhebliche Abweichungen durch eine Ignoranz von Mitarbeiterauslastungen und davon abh{\"a}ngiger Bearbeitungszeiten entstehen. Deshalb ist eine Integration zu empfehlen. Allerdings wird auch deutlich, dass weitere Forschungen notwendig sind, speziell f{\"u}r die Bestimmung geeigneter Ersch{\"o}pfungsfunktionen, so wie beispielsweise Funktionen f{\"u}r Lerneffekte existieren.}, subject = {Fertigungsprogrammplanung}, language = {en} } @article{Herrmann, author = {Herrmann, Frank}, title = {Scheduling a flow shop with simultaneously loaded stations: A real world application}, series = {Journal of Control Science and Engineering}, volume = {3}, journal = {Journal of Control Science and Engineering}, doi = {10.17265/2328-2231/2015.03.004}, pages = {147 -- 163}, abstract = {Companies use special designed flow shops, in order to satisfy specific demands. Products need to be transported (from one station to the next station) by a crane and the way of working of this crane excludes the intermediate storage (of a work piece). In addition, the way of working restricts the set of feasible schedules even more than the no-buffer restriction discussed in the literature in the case of limited storage. Since this scheduling problem is integrated in the usual hierarchical planning, the tardiness is minimised. A linear optimisation model is presented to provide a formal description of this NP-hard problem. It is also used to explain the performance of priority rule based heuristic solutions on small test problems. In detail, priority rules as well as a priority rule based branch and bound procedure are analysed; priority rules are regarded, because a priority rule is still the standard procedure for on-line scheduling in industrial practise. Out of successful priority rules in the literature the best one is identified by an extensive simulative investigation. An improved look-ahead is realised by a restricted search over all possible schedules.}, subject = {Fließfertigung}, language = {en} }