@article{WerkhausenCroninAlbrachtetal.2019, author = {Werkhausen, Amelie and Cronin, Neil J. and Albracht, Kirsten and Paulsen, G{\o}ran and Larsen, Askild V. and Bojsen-M{\o}ller, Jens and Seynnes, Olivier R.}, title = {Training-induced increase in Achilles tendon stiffness affects tendon strain pattern during running}, series = {PeerJ}, journal = {PeerJ}, publisher = {Peer}, address = {London}, issn = {21678359}, doi = {10.7717/peerj.6764}, pages = {18 Seiten}, year = {2019}, abstract = {Background During the stance phase of running, the elasticity of the Achilles tendon enables the utilisation of elastic energy and allows beneficial contractile conditions for the triceps surae muscles. However, the effect of changes in tendon mechanical properties induced by chronic loading is still poorly understood. We tested the hypothesis that a training-induced increase in Achilles tendon stiffness would result in reduced tendon strain during the stance phase of running, which would reduce fascicle strains in the triceps surae muscles, particularly in the mono-articular soleus. Methods Eleven subjects were assigned to a training group performing isometric singleleg plantarflexion contractions three times per week for ten weeks, and another ten subjects formed a control group. Before and after the training period, Achilles tendon stiffness was estimated, and muscle-tendon mechanics were assessed during running at preferred speed using ultrasonography, kinematics and kinetics. Results Achilles tendon stiffness increased by 18\% (P <0:01) in the training group, but the associated reduction in strain seen during isometric contractions was not statistically significant. Tendon elongation during the stance phase of running was similar after training, but tendon recoil was reduced by 30\% (P <0:01), while estimated tendon force remained unchanged. Neither gastrocnemius medialis nor soleus fascicle shortening during stance was affected by training. Discussion These results show that a training-induced increase in Achilles tendon stiffness altered tendon behaviour during running. Despite training-induced changes in tendon mechanical properties and recoil behaviour, the data suggest that fascicle shortening patterns were preserved for the running speed that we examined. The asymmetrical changes in tendon strain patterns supports the notion that simple inseries models do not fully explain the mechanical output of the muscle-tendon unit during a complex task like running.}, language = {en} } @article{WerkhausenCroninAlbrachtetal.2019, author = {Werkhausen, Amelie and Cronin, Neil J. and Albracht, Kirsten and Bojsen-M{\o}ller, Jens and Seynnes, Olivier R.}, title = {Distinct muscle-tendon interaction during running at different speeds and in different loading conditions}, series = {Journal of Applied Physiology}, volume = {127}, journal = {Journal of Applied Physiology}, number = {1}, issn = {1522-1601}, doi = {10.1152/japplphysiol.00710.2018}, pages = {246 -- 253}, year = {2019}, language = {en} } @article{WerkhausenAlbrachtCroninetal.2017, author = {Werkhausen, Amelie and Albracht, Kirsten and Cronin, Neil J. and Meier, Rahel and Mojsen-Moeller, Jens and Seynnes, Olivier R.}, title = {Modulation of muscle-tendon interaction in the human triceps surae during an energy dissipation task}, series = {Journal of Experimental Biology}, volume = {220}, journal = {Journal of Experimental Biology}, number = {22}, issn = {0022-0949}, doi = {10.1242/jeb.164111}, pages = {4141 -- 4149}, year = {2017}, language = {en} } @article{WerkhausenAlbrachtCroninetal.2018, author = {Werkhausen, Amelie and Albracht, Kirsten and Cronin, Neil J and Paulsen, G{\o}ran and Bojsen-M{\o}ller, Jens and Seynnes, Olivier R}, title = {Effect of training-induced changes in achilles tendon stiffness on muscle-tendon behavior during landing}, series = {Frontiers in physiology}, journal = {Frontiers in physiology}, number = {9}, publisher = {Frontiers Research Foundation}, address = {Lausanne}, issn = {1664-042X}, doi = {10.3389/fphys.2018.00794}, pages = {11 Seiten}, year = {2018}, abstract = {During rapid deceleration of the body, tendons buffer part of the elongation of the muscle-tendon unit (MTU), enabling safe energy dissipation via eccentric muscle contraction. Yet, the influence of changes in tendon stiffness within the physiological range upon these lengthening contractions is unknown. This study aimed to examine the effect of training-induced stiffening of the Achilles tendon on triceps surae muscle-tendon behavior during a landing task. Twenty-one male subjects were assigned to either a 10-week resistance-training program consisting of single-leg isometric plantarflexion (n = 11) or to a non-training control group (n = 10). Before and after the training period, plantarflexion force, peak Achilles tendon strain and stiffness were measured during isometric contractions, using a combination of dynamometry, ultrasound and kinematics data. Additionally, testing included a step-landing task, during which joint mechanics and lengths of gastrocnemius and soleus fascicles, Achilles tendon, and MTU were determined using synchronized ultrasound, kinematics and kinetics data collection. After training, plantarflexion strength and Achilles tendon stiffness increased (15 and 18\%, respectively), and tendon strain during landing remained similar. Likewise, lengthening and negative work produced by the gastrocnemius MTU did not change detectably. However, in the training group, gastrocnemius fascicle length was offset (8\%) to a longer length at touch down and, surprisingly, fascicle lengthening and velocity were reduced by 27 and 21\%, respectively. These changes were not observed for soleus fascicles when accounting for variation in task execution between tests. These results indicate that a training-induced increase in tendon stiffness does not noticeably affect the buffering action of the tendon when the MTU is rapidly stretched. Reductions in gastrocnemius fascicle lengthening and lengthening velocity during landing occurred independently from tendon strain. Future studies are required to provide insight into the mechanisms underpinning these observations and their influence on energy dissipation.}, language = {en} } @article{WerfelGuenthnerHapfelmeieretal.2022, author = {Werfel, Stanislas and G{\"u}nthner, Roman and Hapfelmeier, Alexander and Hanssen, Henner and Kotliar, Konstantin and Heemann, Uwe and Schmaderer, Christoph}, title = {Identification of cardiovascular high-risk groups from dynamic retinal vessel signals using untargeted machine learning}, series = {Cardiovascular Research}, volume = {118}, journal = {Cardiovascular Research}, number = {2}, editor = {Guzik, Tomasz J.}, publisher = {Oxford University Press}, address = {Oxford}, issn = {0008-6363}, doi = {10.1093/cvr/cvab040}, pages = {612 -- 621}, year = {2022}, abstract = {Dynamic retinal vessel analysis (DVA) provides a non-invasive way to assess microvascular function in patients and potentially to improve predictions of individual cardiovascular (CV) risk. The aim of our study was to use untargeted machine learning on DVA in order to improve CV mortality prediction and identify corresponding response alterations.}, language = {en} } @article{WegmannHacklStaatetal.2016, author = {Wegmann, Kilian and Hackl, Michael and Staat, Manfred and Mayer, Katharina and M{\"u}ller, Lars-Peter}, title = {Double plate osteosynthesis of proximal ulna fractures: biomechanical and clinical results}, series = {Knee surgery, sports traumatology, arthroscopy}, volume = {Volume 24}, journal = {Knee surgery, sports traumatology, arthroscopy}, number = {Supplement 1}, publisher = {Springer}, address = {Berlin}, issn = {0942-2056}, doi = {10.1007/s00167-016-4079-0}, pages = {58 -- 59}, year = {2016}, abstract = {While plate fixation of proximal ulna fractures might lead to superior clinical results compared to tension band wiring, regular plates represent an established risk factor for wound complications. The olecranon double plates (Medartis, Basel, CH) might decrease complications related to the osteosynthesis because of their low profile and better anatomical fit. This study aimed to evaluate the biomechanical performance and clinical results of the olecranon double plates.}, language = {en} } @article{WaldvogelRitzmannFreyleretal.2021, author = {Waldvogel, Janice and Ritzmann, Ramona and Freyler, Kathrin and Helm, Michael and Monti, Elena and Albracht, Kirsten and St{\"a}udle, Benjamin and Gollhofer, Albert and Narici, Marco}, title = {The Anticipation of Gravity in Human Ballistic Movement}, series = {Frontiers in Physiology}, journal = {Frontiers in Physiology}, publisher = {Frontiers}, address = {Lausanne}, issn = {1664-042X}, doi = {10.3389/fphys.2021.614060}, year = {2021}, abstract = {Stretch-shortening type actions are characterized by lengthening of the pre-activated muscle-tendon unit (MTU) in the eccentric phase immediately followed by muscle shortening. Under 1 g, pre-activity before and muscle activity after ground contact, scale muscle stiffness, which is crucial for the recoil properties of the MTU in the subsequent push-off. This study aimed to examine the neuro-mechanical coupling of the stretch-shortening cycle in response to gravity levels ranging from 0.1 to 2 g. During parabolic flights, 17 subjects performed drop jumps while electromyography (EMG) of the lower limb muscles was combined with ultrasound images of the gastrocnemius medialis, 2D kinematics and kinetics to depict changes in energy management and performance. Neuro-mechanical coupling in 1 g was characterized by high magnitudes of pre-activity and eccentric muscle activity allowing an isometric muscle behavior during ground contact. EMG during pre-activity and the concentric phase systematically increased from 0.1 to 1 g. Below 1 g the EMG in the eccentric phase was diminished, leading to muscle lengthening and reduced MTU stretches. Kinetic energy at take-off and performance were decreased compared to 1 g. Above 1 g, reduced EMG in the eccentric phase was accompanied by large MTU and muscle stretch, increased joint flexion amplitudes, energy loss and reduced performance. The energy outcome function established by linear mixed model reveals that the central nervous system regulates the extensor muscles phase- and load-specifically. In conclusion, neuro-mechanical coupling appears to be optimized in 1 g. Below 1 g, the energy outcome is compromised by reduced muscle stiffness. Above 1 g, loading progressively induces muscle lengthening, thus facilitating energy dissipation.}, language = {en} } @article{WaldvogelFreylerHelmetal.2023, author = {Waldvogel, Janice and Freyler, Kathrin and Helm, Michael and Monti, Elena and St{\"a}udle, Benjamin and Gollhofer, Albert and Narici, Marco V. and Ritzmann, Ramona and Albracht, Kirsten}, title = {Changes in gravity affect neuromuscular control, biomechanics, and muscle-tendon mechanics in energy storage and dissipation tasks}, series = {Journal of Applied Physiology}, volume = {134}, journal = {Journal of Applied Physiology}, number = {1}, publisher = {American Physiological Society}, address = {Bethesda, Md.}, issn = {1522-1601 (Onlineausgabe)}, doi = {10.1152/japplphysiol.00279.2022}, pages = {190 -- 202}, year = {2023}, abstract = {This study evaluates neuromechanical control and muscle-tendon interaction during energy storage and dissipation tasks in hypergravity. During parabolic flights, while 17 subjects performed drop jumps (DJs) and drop landings (DLs), electromyography (EMG) of the lower limb muscles was combined with in vivo fascicle dynamics of the gastrocnemius medialis, two-dimensional (2D) kinematics, and kinetics to measure and analyze changes in energy management. Comparisons were made between movement modalities executed in hypergravity (1.8 G) and gravity on ground (1 G). In 1.8 G, ankle dorsiflexion, knee joint flexion, and vertical center of mass (COM) displacement are lower in DJs than in DLs; within each movement modality, joint flexion amplitudes and COM displacement demonstrate higher values in 1.8 G than in 1 G. Concomitantly, negative peak ankle joint power, vertical ground reaction forces, and leg stiffness are similar between both movement modalities (1.8 G). In DJs, EMG activity in 1.8 G is lower during the COM deceleration phase than in 1 G, thus impairing quasi-isometric fascicle behavior. In DLs, EMG activity before and during the COM deceleration phase is higher, and fascicles are stretched less in 1.8 G than in 1 G. Compared with the situation in 1 G, highly task-specific neuromuscular activity is diminished in 1.8 G, resulting in fascicle lengthening in both movement modalities. Specifically, in DJs, a high magnitude of neuromuscular activity is impaired, resulting in altered energy storage. In contrast, in DLs, linear stiffening of the system due to higher neuromuscular activity combined with lower fascicle stretch enhances the buffering function of the tendon, and thus the capacity to safely dissipate energy.}, language = {en} } @article{VuStaat2004, author = {Vu, Duc-Khoi and Staat, Manfred}, title = {An algorithm for shakedown analysis of structure with temperature dependent yield stress}, year = {2004}, abstract = {This work is an attempt to answer the question: How to use convex programming in shakedown analysis of structures made of materials with temperature-dependent properties. Based on recently established shakedown theorems and formulations, a dual relationship between upper and lower bounds of the shakedown limit load is found, an algorithmfor shakedown analysis is proposed. While the original problem is neither convex nor concave, the algorithm presented here has the advantage of employing convex programming tools.}, subject = {Einspielen }, language = {en} } @article{VuStaatTran2007, author = {Vu, Duc Khoi and Staat, Manfred and Tran, Ich Thinh}, title = {Analysis of pressure equipment by application of the primal-dual theory of shakedown}, series = {Communications in Numerical Methods in Engineering. 23 (2007), H. 3}, journal = {Communications in Numerical Methods in Engineering. 23 (2007), H. 3}, isbn = {1069-8299}, pages = {213 -- 225}, year = {2007}, language = {en} } @article{VuStaat2007, author = {Vu, Duc Khoi and Staat, Manfred}, title = {Shakedown analysis of structures made of materials with temperature-dependent yield stress}, series = {International Journal of Solids and Structures. 44 (2007), H. 13}, journal = {International Journal of Solids and Structures. 44 (2007), H. 13}, isbn = {0020-7683}, pages = {4524 -- 4540}, year = {2007}, language = {en} } @article{VantStaatBaroud2008, author = {Vant, Christianne and Staat, Manfred and Baroud, Gamal}, title = {Percutaneous Vertebroplasty: A Review of Two Intraoperative Complications}, series = {Bioengineering in Cell and Tissue Research / Artmann, Gerhard M. ; Chien, Shu (Eds.)}, journal = {Bioengineering in Cell and Tissue Research / Artmann, Gerhard M. ; Chien, Shu (Eds.)}, publisher = {Springer}, address = {Berlin}, isbn = {978-3-540-75408-4}, pages = {527 -- 539}, year = {2008}, language = {en} } @article{UysalFiratCreutzetal.2022, author = {Uysal, Karya and Firat, Ipek Serat and Creutz, Till and Aydin, Inci Cansu and Artmann, Gerhard and Teusch, Nicole and Temiz Artmann, Ayseg{\"u}l}, title = {A novel in vitro wound healing assay using free-standing, ultra-thin PDMS membranes}, series = {membranes}, volume = {2023}, journal = {membranes}, number = {13(1)}, publisher = {MDPI}, address = {Basel}, doi = {10.3390/membranes13010022}, pages = {Artikel 22}, year = {2022}, abstract = {Advances in polymer science have significantly increased polymer applications in life sciences. We report the use of free-standing, ultra-thin polydimethylsiloxane (PDMS) membranes, called CellDrum, as cell culture substrates for an in vitro wound model. Dermal fibroblast monolayers from 28- and 88-year-old donors were cultured on CellDrums. By using stainless steel balls, circular cell-free areas were created in the cell layer (wounding). Sinusoidal strain of 1 Hz, 5\% strain, was applied to membranes for 30 min in 4 sessions. The gap circumference and closure rate of un-stretched samples (controls) and stretched samples were monitored over 4 days to investigate the effects of donor age and mechanical strain on wound closure. A significant decrease in gap circumference and an increase in gap closure rate were observed in trained samples from younger donors and control samples from older donors. In contrast, a significant decrease in gap closure rate and an increase in wound circumference were observed in the trained samples from older donors. Through these results, we propose the model of a cell monolayer on stretchable CellDrums as a practical tool for wound healing research. The combination of biomechanical cell loading in conjunction with analyses such as gene/protein expression seems promising beyond the scope published here.}, language = {en} } @article{UysalCreutzFiratetal.2022, author = {Uysal, Karya and Creutz, Till and Firat, Ipek Seda and Artmann, Gerhard and Teusch, Nicole and Temiz Artmann, Ayseg{\"u}l}, title = {Bio-functionalized ultra-thin, large-area and waterproof silicone membranes for biomechanical cellular loading and compliance experiments}, series = {Polymers}, volume = {14}, journal = {Polymers}, number = {11}, publisher = {MDPI}, address = {Basel}, issn = {2073-4360}, pages = {2213}, year = {2022}, abstract = {Biocompatibility, flexibility and durability make polydimethylsiloxane (PDMS) membranes top candidates in biomedical applications. CellDrum technology uses large area, <10 µm thin membranes as mechanical stress sensors of thin cell layers. For this to be successful, the properties (thickness, temperature, dust, wrinkles, etc.) must be precisely controlled. The following parameters of membrane fabrication by means of the Floating-on-Water (FoW) method were investigated: (1) PDMS volume, (2) ambient temperature, (3) membrane deflection and (4) membrane mechanical compliance. Significant differences were found between all PDMS volumes and thicknesses tested (p < 0.01). They also differed from the calculated values. At room temperatures between 22 and 26 °C, significant differences in average thickness values were found, as well as a continuous decrease in thicknesses within a 4 °C temperature elevation. No correlation was found between the membrane thickness groups (between 3-4 µm) in terms of deflection and compliance. We successfully present a fabrication method for thin bio-functionalized membranes in conjunction with a four-step quality management system. The results highlight the importance of tight regulation of production parameters through quality control. The use of membranes described here could also become the basis for material testing on thin, viscous layers such as polymers, dyes and adhesives, which goes far beyond biological applications.}, language = {en} } @article{UllrichGrottkeRossaintetal.2010, author = {Ullrich, Sebastian and Grottke, Oliver and Rossaint, Rolf and Staat, Manfred and Deserno, Thomas M. and Kuhlen, Torsten}, title = {Virtual Needle Simulation with Haptics for Regional Anaesthesia}, pages = {1 -- 3}, year = {2010}, language = {en} } @article{TurlybekulyPogrebnjakSukhodubetal.2019, author = {Turlybekuly, Amanzhol and Pogrebnjak, Alexander and Sukhodub, L. F. and Sukhodub, Liudmyla B. and Kistaubayeva, A. S. and Savitskaya, Irina and Shokatayeva, D. H. and Bondar, Oleksandr V. and Shaimardanov, Z. K. and Plotnikov, Sergey V. and Shaimardanova, B. H. and Digel, Ilya}, title = {Synthesis, characterization, in vitro biocompatibility and antibacterial properties study of nanocomposite materials based on hydroxyapatite-biphasic ZnO micro- and nanoparticles embedded in Alginate matrix}, series = {Materials Science and Engineering C}, volume = {104}, journal = {Materials Science and Engineering C}, number = {Article number 109965}, publisher = {Elsevier}, address = {Amsterdam}, doi = {10.1016/j.msec.2019.109965}, year = {2019}, language = {en} } @article{TuraliyevaYeshibaevSaparbekovaetal.2016, author = {Turaliyeva, M. and Yeshibaev, A. and Saparbekova, A. and Akynova, L. and Abildayeva, R. and Sadenova, M. and Sartayeva, K. and Schieffer, Andre and Digel, Ilya}, title = {Species composition and injuriousness of stranger xylophilous fauna affecting indigenous urban dendroflora of Central Asia}, series = {Asian journal of microbiology, biotechnology \& environmental sciences : AJMBES}, volume = {18}, journal = {Asian journal of microbiology, biotechnology \& environmental sciences : AJMBES}, number = {2}, publisher = {EM International}, issn = {0972-3005}, pages = {359 -- 366}, year = {2016}, abstract = {At the present time, one of the most serious environmental problems of Central Asia and South Kazakhstan is the ongoing large-scale deterioration of principal urban tree populations. Several major centers of massive spread of invasive plant pests have been found in urban dendroflora of this region. The degree of damage of seven most wide-spread aboriginal tree species was found to range from 21.4±1.1 to 85.4±1.8\%. In particular, the integrity of the native communities of sycamore (Platanus spp.), willow (Salix spp.), poplar (Populus spp.) and elm (Ulmus spp.) is highly endangered. Our taxonomic analysis of the most dangerous tree pests of the region has revealed them as neobiontic xylophilous insects such as Cossus cossus L. (Order: Lepidoptera L.) Monochamus urussovi Fisch., Monochamus sutor L., Acanthocinus aedelis L. and {\~N}etonia aureate L. (Order: Coleoptera L.). We relate the origin of this threatening trend with the import of industrial wood in the mid 90’s of the last century that was associated with high degree of the constructional work in the region. Because of the absence of efficient natural predators of the pest species, the application of microbiological methods of the pest control and limitation is suggested.}, language = {en} } @article{TuraliyevaYeshibaevDigeletal.2014, author = {Turaliyeva, M. and Yeshibaev, A. and Digel, Ilya and Elibayeva, G. and Sydykova, A. and Uspabayeva, A. and Dosybayeva, G. and Zhylysbayeva, A. and Lakhanova, K.}, title = {Molecular-genetic identification of emerged novel invasive pathogens of Asiatic Elm Ulmus pumila L}, series = {Life science journal}, volume = {11}, journal = {Life science journal}, number = {Spec. iss. 5s}, publisher = {Marsland Press}, address = {New York}, issn = {1097-8135}, doi = {10.7537/marslsj1105s14.33}, pages = {171 -- 175}, year = {2014}, abstract = {The dwarf elm Ulmus pumila L. (Ulmaceae) is one of indigenous species of flora in Kazakhstan and forms a basis of dendroflora in virtually all settlements of the region. In the past decade, multiple outbreaks of previously unknown diseases of the small-leaved elm have been registered. In our study, by the molecular-genetic analysis it was found that the pathogens responsible for the outbreaks are microfungi belonging to the genus Fusarium - F. solani and F. oxysporum. The nucleotide sequences (ITS regions) isolated from the diseased trees showed very high similarity with the GenBank control numbers EU625403.1 and FJ478128.1 (100.0 and 99.0 \% respectively). Oncoming research will focus on the search of natural microbial antagonists of the discovered phytopathogens.}, language = {en} } @article{TrzewikTemizArtmannLinderetal.2004, author = {Trzewik, J{\"u}rgen and Temiz Artmann, Ayseg{\"u}l and Linder, Peter and Demirci, T. and Digel, Ilya and Artmann, Gerhard}, title = {Evaluation of lateral mechanical tension in thin-film tissue constructs}, series = {Annals of Biomedical Engineering. 32 (2004), H. 9}, journal = {Annals of Biomedical Engineering. 32 (2004), H. 9}, isbn = {1573-9686}, pages = {1243 -- 1251}, year = {2004}, language = {en} } @article{TranStaat2010, author = {Tran, Thanh Ngoc and Staat, Manfred}, title = {Shakedown analysis of two dimensional structures by an edge-based smoothed finite element method}, pages = {1 -- 7}, year = {2010}, language = {en} }