TY  - RPRT
A1  - Siegert, Petra
A1  - Bongaerts, Johannes
A1  - Wagner, Torsten
A1  - Schöning, Michael Josef
A1  - Selmer, Thorsten
T1  - Abschlussbericht zum Projekt zur Überwachung biotechnologischer Prozesse mittels Diacetyl-/Acetoin-Biosensor und Evaluierung von Acetoin-Reduktasen zur Verwendung in Biotransformationen
Y1  - 2022
N1  - Laufzeit: 01.01.2016 – 31.12.2019 (verlängert bis 31.12.2020)

Förderkennzeichen: 322-8.03.04.02-FH-Struktur 2016/02

Gefördert durch: Ministerium für Innovation, Wissenschaft und Forschung des Landes Nordrhein-Westfalen
CY  - Aachen
ER  - 
TY  - CHAP
A1  - Burgeth, Bernhard
A1  - Kleefeld, Andreas
A1  - Zhang, Eugene
A1  - Zhang, Yue
ED  - Baudrier, Étienne
ED  - Naegel, Benoît
ED  - Krähenbühl, Adrien
ED  - Tajine, Mohamed
T1  - Towards Topological Analysis of Non-symmetric Tensor Fields via Complexification
T2  - Discrete Geometry and Mathematical Morphology
N2  - Fields of asymmetric tensors play an important role in many applications such as medical imaging (diffusion tensor magnetic resonance imaging), physics, and civil engineering (for example Cauchy-Green-deformation tensor, strain tensor with local rotations, etc.). However, such asymmetric tensors are usually symmetrized and then further processed. Using this procedure results in a loss of information. A new method for the processing of asymmetric tensor fields is proposed restricting our attention to tensors of second-order given by a 2x2 array or matrix with real entries. This is achieved by a transformation resulting in Hermitian matrices that have an eigendecomposition similar to symmetric matrices. With this new idea numerical results for real-world data arising from a deformation of an object by external forces are given. It is shown that the asymmetric part indeed contains valuable information.
Y1  - 2022
SN  - 978-3-031-19897-7
U6  - https://doi.org/10.1007/978-3-031-19897-7_5
N1  - Second International Joint Conference, DGMM 2022, Strasbourg, France, October 24–27, 2022
N1  - Corresponding author: Andreas Kleefeld
SP  - 48
EP  - 59
PB  - Springer
CY  - Cham
ER  - 
TY  - JOUR
A1  - Rübbelke, Dirk
A1  - Vögele, Stefan
A1  - Grajewski, Matthias
A1  - Zobel, Luzy
T1  - Hydrogen-based steel production and global climate protection: An empirical analysis of the potential role of a European cross border adjustment mechanism
JF  - Journal of Cleaner Production
N2  - The European Union's aim to become climate neutral by 2050 necessitates ambitious efforts to reduce carbon emissions. Large reductions can be attained particularly in energy intensive sectors like iron and steel. In order to prevent the relocation of such industries outside the EU in the course of tightening environmental regulations, the establishment of a climate club jointly with other large emitters and alternatively the unilateral implementation of an international cross-border carbon tax mechanism are proposed. This article focuses on the latter option choosing the steel sector as an example. In particular, we investigate the financial conditions under which a European cross border mechanism is capable to protect hydrogen-based steel production routes employed in Europe against more polluting competition from abroad. By using a floor price model, we assess the competitiveness of different steel production routes in selected countries. We evaluate the climate friendliness of steel production on the basis of specific GHG emissions. In addition, we utilize an input-output price model. It enables us to assess impacts of rising cost of steel production on commodities using steel as intermediates. Our results raise concerns that a cross-border tax mechanism will not suffice to bring about competitiveness of hydrogen-based steel production in Europe because the cost tends to remain higher than the cost of steel production in e.g. China. Steel is a classic example for a good used mainly as intermediate for other products. Therefore, a cross-border tax mechanism for steel will increase the price of products produced in the EU that require steel as an input. This can in turn adversely affect competitiveness of these sectors. Hence, the effects of higher steel costs on European exports should be borne in mind and could require the cross-border adjustment mechanism to also subsidize exports.
Y1  - 2022
U6  - https://doi.org/10.1016/j.jclepro.2022.135040
SN  - 0959-6526
VL  - 380
IS  - Part 2, Art. Nr.:135040
PB  - Elsevier
ER  - 
TY  - CHAP
A1  - Blaneck, Patrick Gustav
A1  - Bornheim, Tobias
A1  - Grieger, Niklas
A1  - Bialonski, Stephan
T1  - Automatic readability assessment of german sentences with transformer ensembles
T2  - Proceedings of the GermEval 2022 Workshop on Text Complexity Assessment of German Text
N2  - Reliable methods for automatic readability assessment have the potential to impact a variety of fields, ranging from machine translation to self-informed learning. Recently, large language models for the German language (such as GBERT and GPT-2-Wechsel) have become available, allowing to develop Deep Learning based approaches that promise to further improve automatic readability assessment. In this contribution, we studied the ability of ensembles of fine-tuned GBERT and GPT-2-Wechsel models to reliably predict the readability of German sentences. We combined these models with linguistic features and investigated the dependence of prediction performance on ensemble size and composition. Mixed ensembles of GBERT and GPT-2-Wechsel performed better than ensembles of the same size consisting of only GBERT or GPT-2-Wechsel models. Our models were evaluated in the GermEval 2022 Shared Task on Text Complexity Assessment on data of German sentences. On out-of-sample data, our best ensemble achieved a root mean squared error of 0:435.
Y1  - 2022
U6  - https://doi.org/10.48550/arXiv.2209.04299
N1  - Proceedings of the 18th Conference on Natural Language Processing / Konferenz zur Verarbeitung natürlicher Sprache (KONVENS 2022), 12-15 September, 2022, University of Potsdam, Potsdam, Germany
SP  - 57
EP  - 62
PB  - Association for Computational Linguistics
CY  - Potsdam
ER  - 
TY  - JOUR
A1  - Defosse, Jerome
A1  - Kleinschmidt, Joris
A1  - Schmutz, Axel
A1  - Loop, Torsten
A1  - Staat, Manfred
A1  - Gatzweiler, Karl-Heinz
A1  - Wappler, Frank
A1  - Schieren, Mark
T1  - Dental strain on maxillary incisors during tracheal intubation with double-lumen tubes and different laryngoscopy techniques - a blinded manikin study
JF  - Journal of Cardiothoracic and Vascular Anesthesia
KW  - anaesthetic complications
KW  - dental trauma
KW  - difficult airway
KW  - double-lumen tube intubation
KW  - videolaryngoscopy
Y1  - 2022
U6  - https://doi.org/10.1053/j.jvca.2022.02.017
SN  - 1053-0770
VL  - 36
IS  - 8, Part B
SP  - 3021
EP  - 3027
PB  - Elsevier
CY  - New York, NY
ER  - 
TY  - JOUR
A1  - Colombo, Daniele
A1  - Drira, Slah
A1  - Frotscher, Ralf
A1  - Staat, Manfred
T1  - An element-based formulation for ES-FEM and FS-FEM models for implementation in standard solid mechanics finite element codes for 2D and 3D static analysis
JF  - International Journal for Numerical Methods in Engineering
N2  - Edge-based and face-based smoothed finite element methods (ES-FEM and FS-FEM, respectively) are modified versions of the finite element method allowing to achieve more accurate results and to reduce sensitivity to mesh distortion, at least for linear elements. These properties make the two methods very attractive. However, their implementation in a standard finite element code is nontrivial because it requires heavy and extensive modifications to the code architecture. In this article, we present an element-based formulation of ES-FEM and FS-FEM methods allowing to implement the two methods in a standard finite element code with no modifications to its architecture. Moreover, the element-based formulation permits to easily manage any type of element, especially in 3D models where, to the best of the authors' knowledge, only tetrahedral elements are used in FS-FEM applications found in the literature. Shape functions for non-simplex 3D elements are proposed in order to apply FS-FEM to any standard finite element.
KW  - distorted element
KW  - ES-FEM
KW  - FS-FEM
KW  - non-simplex S-FEM elements
KW  - S-FEM
Y1  - 2022
U6  - https://doi.org/10.1002/nme.7126
SN  - 1097-0207
VL  - 124
IS  - 2
SP  - 402
EP  - 433
PB  - Wiley
CY  - Chichester
ER  - 
TY  - JOUR
A1  - Bhattarai, Aroj
A1  - May, Charlotte Anabell
A1  - Staat, Manfred
A1  - Kowalczyk, Wojciech
A1  - Tran, Thanh Ngoc
T1  - Layer-specific damage modeling of porcine large intestine under biaxial tension
JF  - Bioengineering
N2  - The mechanical behavior of the large intestine beyond the ultimate stress has never been investigated. Stretching beyond the ultimate stress may drastically impair the tissue microstructure, which consequently weakens its healthy state functions of absorption, temporary storage, and transportation for defecation. Due to closely similar microstructure and function with humans, biaxial tensile experiments on the porcine large intestine have been performed in this study. In this paper, we report hyperelastic characterization of the large intestine based on experiments in 102 specimens. We also report the theoretical analysis of the experimental results, including an exponential damage evolution function. The fracture energies and the threshold stresses are set as damage material parameters for the longitudinal muscular, the circumferential muscular and the submucosal collagenous layers. A biaxial tensile simulation of a linear brick element has been performed to validate the applicability of the estimated material parameters. The model successfully simulates the biomechanical response of the large intestine under physiological and non-physiological loads.
KW  - biaxial tensile experiment
KW  - anisotropy
KW  - hyperelastic
KW  - constitutive modeling
KW  - damage
Y1  - 2022
U6  - https://doi.org/10.3390/bioengineering9100528
SN  - 2306-5354
N1  - Der Artikel gehört zum Sonderheft "Computational Biomechanics"
VL  - 9
IS  - 10, Early Access
SP  - 1
EP  - 17
PB  - MDPI
CY  - Basel
ER  - 
TY  - CHAP
A1  - Büsgen, André
A1  - Klöser, Lars
A1  - Kohl, Philipp
A1  - Schmidts, Oliver
A1  - Kraft, Bodo
A1  - Zündorf, Albert
T1  - Exploratory analysis of chat-based black market profiles with natural language processing
T2  - Proceedings of the 11th International Conference on Data Science, Technology and Applications
N2  - Messenger apps like WhatsApp or Telegram are an integral part of daily communication. Besides the various positive effects, those services extend the operating range of criminals. Open trading groups with many thousand participants emerged on Telegram. Law enforcement agencies monitor suspicious users in such chat rooms. This research shows that text analysis, based on natural language processing, facilitates this through a meaningful domain overview and detailed investigations. We crawled a corpus from such self-proclaimed black markets and annotated five attribute types products, money, payment methods, user names, and locations. Based on each message a user sends, we extract and group these attributes to build profiles. Then, we build features to cluster the profiles. Pretrained word vectors yield better unsupervised clustering results than current
state-of-the-art transformer models. The result is a semantically meaningful high-level overview of the user landscape of black market chatrooms. Additionally, the extracted structured information serves as a foundation for further data exploration, for example, the most active users or preferred payment methods.
KW  - Clustering
KW  - Natural Language Processing
KW  - Information Extraction
KW  - Profile Extraction
KW  - Text Mining
Y1  - 2022
SN  - 978-989-758-583-8
U6  - https://doi.org/10.5220/0011271400003269
SN  - 2184-285X
N1  - 11th International Conference on Data Science, Technology and Applications DATA - Volume 1, 83-94, 2022, Lisbon, Portugal
SP  - 83
EP  - 94
ER  - 
TY  - BOOK
A1  - Engelmann, Ulrich M.
T1  - Zielführend moderieren
N2  - In der Teamarbeit wird Moderation zum Erfolgsfaktor, der jedoch häufig unterschätzt wird. Ausgehend vom persönlichen Kompetenzniveau verknüpft dieses Buch Grundlagen und Methoden zu Wegen, um Ihre persönliche Entwicklung individuell zu begleiten: Neulinge finden hilfreiche Checklisten und Basistechniken für ihre ersten Moderationen, Fortgeschrittene wertvolle Praxistipps und Methoden für den Ausbau ihrer Moderationskompetenz. Profis schließlich genießen eine raffinierte Aussicht auf weniger bekannte Techniken und neue Anwendungen. Weiterführende Exkurse zum Meeting-Management und zur Online-Moderation runden den Anwendungshorizont ab.

Ob in Beruf, Studium oder Ehrenamt – derart ausgestattet gelingen Ihre eigene sowie die Entwicklung Ihres Teams durch zielführende Moderationen.
Y1  - 2022
SN  - 9783838556895
U6  - https://doi.org/10.36198/9783838556895
PB  - UVK Verlag
CY  - Stuttgart
ER  - 
TY  - JOUR
A1  - Mandekar, Swati
A1  - Holland, Abigail
A1  - Thielen, Moritz
A1  - Behbahani, Mehdi
A1  - Melnykowycz, Mark
T1  - Advancing towards Ubiquitous EEG, Correlation of In-Ear EEG with Forehead EEG
JF  - Sensors
N2  - Wearable EEG has gained popularity in recent years driven by promising uses outside of clinics and research. The ubiquitous application of continuous EEG requires unobtrusive form-factors that are easily acceptable by the end-users. In this progression, wearable EEG systems have been moving from full scalp to forehead and recently to the ear. The aim of this study is to demonstrate that emerging ear-EEG provides similar impedance and signal properties as established forehead EEG. EEG data using eyes-open and closed alpha paradigm were acquired from ten healthy subjects using generic earpieces fitted with three custom-made electrodes and a forehead electrode (at Fpx) after impedance analysis. Inter-subject variability in in-ear electrode impedance ranged from 20 kΩ to 25 kΩ at 10 Hz. Signal quality was comparable with an SNR of 6 for in-ear and 8 for forehead electrodes. Alpha attenuation was significant during the eyes-open condition in all in-ear electrodes, and it followed the structure of power spectral density plots of forehead electrodes, with the Pearson correlation coefficient of 0.92 between in-ear locations ELE (Left Ear Superior) and ERE (Right Ear Superior) and forehead locations, Fp1 and Fp2, respectively. The results indicate that in-ear EEG is an unobtrusive alternative in terms of impedance, signal properties and information content to established forehead EEG.
KW  - in-ear EEG
KW  - correlation
KW  - forehead EEG
KW  - impedance spectroscopy
KW  - biopotential electrodes
Y1  - 2022
U6  - https://doi.org/10.3390/s22041568
SN  - 1424-8220
VL  - 22
IS  - 4
SP  - 1
EP  - 19
PB  - MDPI
CY  - Basel
ER  - 
TY  - JOUR
A1  - Philipp, Mohr
A1  - Efthimiou, Nikos
A1  - Pagano, Fiammetta
A1  - Kratochwil, Nicolaus
A1  - Pizzichemi, Marco
A1  - Tsoumpas, Charalampos
A1  - Auffray, Etiennette
A1  - Ziemons, Karl
T1  - Image reconstruction analysis for positron emission tomography with heterostructured scintillators
JF  - IEEE Transactions on Radiation and Plasma Medical Sciences
N2  - The concept of structure engineering has been proposed for exploring the next generation of radiation detectors with improved performance. A TOF-PET geometry with heterostructured scintillators with a pixel size of 3.0×3.1×15 mm3 was simulated using Monte Carlo. The heterostructures consisted of alternating layers of BGO as a dense material with high stopping power and plastic (EJ232) as a fast light emitter. The detector time resolution was calculated as a function of the deposited and shared energy in both materials on an event-by-event basis. While sensitivity was reduced to 32% for 100 μm thick plastic layers and 52% for 50 μm, the CTR distribution improved to 204±49 ps and 220±41 ps respectively, compared to 276 ps that we considered for bulk BGO. The complex distribution of timing resolutions was accounted for in the reconstruction. We divided the events into three groups based on their CTR and modeled them with different Gaussian TOF kernels. On a NEMA IQ phantom, the heterostructures had better contrast recovery in early iterations. On the other hand, BGO achieved a better contrast to noise ratio (CNR) after the 15th iteration due to the higher sensitivity. The developed simulation and reconstruction methods constitute new tools for evaluating different detector designs with complex time responses.
KW  - TOF PET
KW  - Heterostructure
KW  - Metascintillator
KW  - Multiple TOF kernels
KW  - Image Reconstruction
Y1  - 2022
U6  - https://doi.org/10.1109/TRPMS.2022.3208615
SN  - 2469-7311
SN  - 2469-7303
VL  - 7
IS  - 1
SP  - 41
EP  - 51
PB  - IEEE
CY  - New York, NY
ER  - 
TY  - JOUR
A1  - Baringhaus, Ludwig
A1  - Gaigall, Daniel
T1  - A goodness-of-fit test for the compound Poisson exponential model
JF  - Journal of Multivariate Analysis
N2  - On the basis of bivariate data, assumed to be observations of independent copies of a random vector (S,N), we consider testing the hypothesis that the distribution of (S,N) belongs to the parametric class of distributions that arise with the compound Poisson exponential model. Typically, this model is used in stochastic hydrology, with N as the number of raindays, and S as total rainfall amount during a certain time period, or in actuarial science, with N as the number of losses, and S as total loss expenditure during a certain time period. The compound Poisson exponential model is characterized in the way that a specific transform associated with the distribution of (S,N) satisfies a certain differential equation. Mimicking the function part of this equation by substituting the empirical counterparts of the transform we obtain an expression the weighted integral of the square of which is used as test statistic. We deal with two variants of the latter, one of which being invariant under scale transformations of the S-part by fixed positive constants. Critical values are obtained by using a parametric bootstrap procedure. The asymptotic behavior of the tests is discussed. A simulation study demonstrates the performance of the tests in the finite sample case. The procedure is applied to rainfall data and to an actuarial dataset. A multivariate extension is also discussed.
KW  - Bootstrapping
KW  - Collective risk model
Y1  - 2022
U6  - https://doi.org/10.1016/j.jmva.2022.105154
SN  - 0047-259X
SN  - 1095-7243
VL  - 195
IS  - Article 105154
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Malinowski, Daniel
A1  - Fournier, Yvan
A1  - Horbach, Andreas
A1  - Frick, Michael
A1  - Magliani, Mirko
A1  - Kalverkamp, Sebastian
A1  - Hildinger, Martin
A1  - Spillner, Jan
A1  - Behbahani, Mehdi
A1  - Hima, Flutura
T1  - Computational fluid dynamics analysis of endoluminal aortic perfusion
JF  - Perfusion
N2  - Introduction: In peripheral percutaneous (VA) extracorporeal membrane oxygenation (ECMO) procedures the femoral arteries perfusion route has inherent disadvantages regarding poor upper body perfusion due to watershed. With the advent of new long flexible cannulas an advancement of the tip up to the ascending aorta has become feasible. To investigate the impact of such long endoluminal cannulas on upper body perfusion, a Computational Fluid Dynamics (CFD) study was performed considering different support levels and three cannula positions.

Methods: An idealized literature-based- and a real patient proximal aortic geometry including an endoluminal cannula were constructed. The blood flow was considered continuous. Oxygen saturation was set to 80% for the blood coming from the heart and to 100% for the blood leaving the cannula. 50% and 90% venoarterial support levels from the total blood flow rate of 6 l/min were investigated for three different positions of the cannula in the aortic arch. 

Results: For both geometries, the placement of the cannula in the ascending aorta led to a superior oxygenation of all aortic blood vessels except for the left coronary artery. Cannula placements at the aortic arch and descending aorta could support supra-aortic arteries, but not the coronary arteries. All positions were able to support all branches with saturated blood at 90% flow volume.

Conclusions: In accordance with clinical observations CFD analysis reveals, that retrograde advancement of a long endoluminal cannula can considerably improve the oxygenation of the upper body and lead to oxygen saturation distributions similar to those of a central cannulation.
KW  - computational fluid dynamics analysis
KW  - simulation
KW  - endoluminal
KW  - aortic perfusion
KW  - extracorporeal membrane oxygenation
Y1  - 2022
U6  - https://doi.org/10.1177/02676591221099809
SN  - 1477-111X
VL  - 0
IS  - 0
SP  - 1
EP  - 8
PB  - Sage
CY  - London
ER  - 
TY  - JOUR
A1  - Lenz, Maximilian
A1  - Kahmann, Stephanie Lucina
A1  - Behbahani, Mehdi
A1  - Pennig, Lenhard
A1  - Hackl, Michael
A1  - Leschinger, Tim
A1  - Müller, Lars Peter
A1  - Wegmann, Kilian
T1  - Influence of rotator cuff preload on fracture configuration in proximal humerus fractures: a proof of concept for fracture simulation
JF  - Archives of Orthopaedic and Trauma Surgery
N2  - Introduction
In regard of surgical training, the reproducible simulation of life-like proximal humerus fractures in human cadaveric specimens is desirable. The aim of the present study was to develop a technique that allows simulation of realistic proximal humerus fractures and to analyse the influence of rotator cuff preload on the generated lesions in regards of fracture configuration.

Materials and methods
Ten cadaveric specimens (6 left, 4 right) were fractured using a custom-made drop-test bench, in two groups. Five specimens were fractured without rotator cuff preload, while the other five were fractured with the tendons of the rotator cuff preloaded with 2 kg each. The humeral shaft and the shortened scapula were potted. The humerus was positioned at 90° of abduction and 10° of internal rotation to simulate a fall on the elevated arm. In two specimens of each group, the emergence of the fractures was documented with high-speed video imaging. Pre-fracture radiographs were taken to evaluate the deltoid-tuberosity index as a measure of bone density. Post-fracture X-rays and CT scans were performed to define the exact fracture configurations. Neer’s classification was used to analyse the fractures.

Results
In all ten cadaveric specimens life-like proximal humerus fractures were achieved. Two III-part and three IV-part fractures resulted in each group. The preloading of the rotator cuff muscles had no further influence on the fracture configuration. High-speed videos of the fracture simulation revealed identical fracture mechanisms for both groups. We observed a two-step fracture mechanism, with initial impaction of the head segment against the glenoid followed by fracturing of the head and the tuberosities and then with further impaction of the shaft against the acromion, which lead to separation of the tuberosities.

Conclusion
A high energetic axial impulse can reliably induce realistic proximal humerus fractures in cadaveric specimens. The preload of the rotator cuff muscles had no influence on initial fracture configuration. Therefore, fracture simulation in the proximal humerus is less elaborate. Using the presented technique, pre-fractured specimens are available for real-life surgical education.
KW  - Proximal humerus fracture
KW  - Biomechanical simulation
KW  - Fracture configuration
KW  - Fracture simulation
KW  - Rotator cuff
Y1  - 2022
U6  - https://doi.org/10.1007/s00402-022-04471-9
SN  - 1434-3916
PB  - Springer
CY  - Berlin, Heidelberg
ER  - 
TY  - JOUR
A1  - Chloé, Radermacher
A1  - Malyaran, Hanna
A1  - Craveiro, Rogerio Bastos
A1  - Peglow, Sarah
A1  - Behbahani, Mehdi
A1  - Pufe, Thomas
A1  - Wolf, Michael
A1  - Neuss, Sabine
T1  - Mechanical loading on cementoblasts: a mini review
JF  - Osteologie
N2  - Orthodontic treatments are concomitant with mechanical forces and thereby cause teeth movements. The applied forces are transmitted to the tooth root and the periodontal ligaments which is compressed on one side and tensed up on the other side. Indeed, strong forces can lead to tooth root resorption and the crown-to-tooth ratio is reduced with the potential for significant clinical impact. The cementum, which covers the tooth root, is a thin mineralized tissue of the periodontium that connects the periodontal ligament with the tooth and is build up by cementoblasts. The impact of tension and compression on these cells is investigated in several in vivo and in vitro studies demonstrating differences in protein expression and signaling pathways. In summary, osteogenic marker changes indicate that cyclic tensile forces support whereas static tension inhibits cementogenesis. Furthermore, cementogenesis experiences the same protein expression changes in static conditions as static tension, but cyclic compression leads to the exact opposite of cyclic tension. Consistent with marker expression changes, the singaling pathways of Wnt/ß-catenin and RANKL/OPG show that tissue compression leads to cementum degradation and tension forces to cementogenesis. However, the cementum, and in particular its cementoblasts, remain a research area which should be explored in more detail to understand the underlying mechanism of bone resorption and remodeling after orthodontic treatments.
KW  - Cementoblast
KW  - Compression
KW  - Tension
KW  - Mechanotransduction
KW  - Forces
Y1  - 2022
U6  - https://doi.org/10.1055/a-1826-0777
SN  - 1019-1291
VL  - 31
IS  - 2
SP  - 111
EP  - 118
PB  - Thieme
CY  - Stuttgart
ER  - 
TY  - JOUR
A1  - Herssens, Nolan
A1  - Cowburn, James
A1  - Albracht, Kirsten
A1  - Braunstein, Bjoern
A1  - Cazzola, Dario
A1  - Colyer, Steffi
A1  - Minetti, Alberto E.
A1  - Pavei, Gaspare
A1  - Rittweger, Jörn
A1  - Weber, Tobias
A1  - Green, David A.
ED  - Cattaneo, Luigi
T1  - Movement in low gravity environments (MoLo) programme – the MoLo-L.O.O.P. study protocol
JF  - PLOS ONE / Public Library of Science
N2  - Exposure to prolonged periods in microgravity is associated with deconditioning of the musculoskeletal system due to chronic changes in mechanical stimulation. Given astronauts will operate on the Lunar surface for extended periods of time, it is critical to quantify both external (e.g., ground reaction forces) and internal (e.g., joint reaction forces) loads of relevant movements performed during Lunar missions. Such knowledge is key to predict musculoskeletal deconditioning and determine appropriate exercise countermeasures associated with extended exposure to hypogravity.
Y1  - 2022
U6  - https://doi.org/10.1371/journal.pone.0278051
SN  - 1932-6203
VL  - 17
IS  - 11
PB  - Plos
CY  - San Francisco
ER  - 
TY  - JOUR
A1  - Stäudle, Benjamin
A1  - Seynnes, Olivier
A1  - Laps, Guido
A1  - Brüggemann, Gert-Peter
A1  - Albracht, Kirsten
T1  - Altered gastrocnemius contractile behavior in former achilles tendon rupture patients during walking
JF  - Frontiers in Physiology
N2  - Achilles tendon rupture (ATR) remains associated with functional limitations years after injury. Architectural remodeling of the gastrocnemius medialis (GM) muscle is typically observed in the affected leg and may compensate force deficits caused by a longer tendon. Yet patients seem to retain functional limitations during—low-force—walking gait. To explore the potential limits imposed by the remodeled GM muscle-tendon unit (MTU) on walking gait, we examined the contractile behavior of muscle fascicles during the stance phase. In a cross-sectional design, we studied nine former patients (males; age: 45 ± 9 years; height: 180 ± 7 cm; weight: 83 ± 6 kg) with a history of complete unilateral ATR, approximately 4 years post-surgery. Using ultrasonography, GM tendon morphology, muscle architecture at rest, and fascicular behavior were assessed during walking at 1.5 m⋅s–1 on a treadmill. Walking patterns were recorded with a motion capture system. The unaffected leg served as control. Lower limbs kinematics were largely similar between legs during walking. Typical features of ATR-related MTU remodeling were observed during the stance sub-phases corresponding to series elastic element (SEE) lengthening (energy storage) and SEE shortening (energy release), with shorter GM fascicles (36 and 36%, respectively) and greater pennation angles (8° and 12°, respectively). However, relative to the optimal fascicle length for force production, fascicles operated at comparable length in both legs. Similarly, when expressed relative to optimal fascicle length, fascicle contraction velocity was not different between sides, except at the time-point of peak series elastic element (SEE) length, where it was 39 ± 49% lower in the affected leg. Concomitantly, fascicles rotation during contraction was greater in the affected leg during the whole stance-phase, and architectural gear ratios (AGR) was larger during SEE lengthening. Under the present testing conditions, former ATR patients had recovered a relatively symmetrical walking gait pattern. Differences in seen AGR seem to accommodate the profound changes in MTU architecture, limiting the required fascicle shortening velocity. Overall, the contractile behavior of the GM fascicles does not restrict length- or velocity-dependent force potentials during this locomotor task.
KW  - tendon rupture
KW  - muscle fascicle behavior
KW  - walking gait
KW  - force generation
KW  - ultrasound imaging
Y1  - 2022
U6  - https://doi.org/10.3389/fphys.2022.792576
SN  - 1664-042X
VL  - 13
PB  - Frontiers Research Foundation
CY  - Lausanne
ER  - 
TY  - JOUR
A1  - Quittmann, Oliver J.
A1  - Abel, Thomas
A1  - Albracht, Kirsten
A1  - Strüder, Heiko K.
T1  - Biomechanics of all-out handcycling exercise: kinetics, kinematics and muscular activity of a 15-s sprint test in able-bodied participants
JF  - Sports Biomechanics
N2  - This study aims to quantify the kinematics, kinetics and muscular activity of all-out handcycling exercise and examine their alterations during the course of a 15-s sprint test. Twelve able-bodied competitive triathletes performed a 15-s all-out sprint test in a recumbent racing handcycle that was attached to an ergometer. During the sprint test, tangential crank kinetics, 3D joint kinematics and muscular activity of 10 muscles of the upper extremity and trunk were examined using a power metre, motion capturing and surface electromyography (sEMG), respectively. Parameters were compared between revolution one (R1), revolution two (R2), the average of revolution 3 to 13 (R3) and the average of the remaining revolutions (R4). Shoulder abduction and internal-rotation increased, whereas maximal shoulder retroversion decreased during the sprint. Except for the wrist angles, angular velocity increased for every joint of the upper extremity. Several muscles demonstrated an increase in muscular activation, an earlier onset of muscular activation in crank cycle and an increased range of activation. During the course of a 15-s all-out sprint test in handcycling, the shoulder muscles and the muscles associated to the push phase demonstrate indications for short-duration fatigue. These findings are helpful to prevent injuries and improve performance in all-out handcycling.
KW  - Handbike
KW  - sEMG
KW  - Paralympic sport
KW  - performance testing
KW  - high-intensity exercise
Y1  - 2022
U6  - https://doi.org/10.1080/14763141.2020.1745266
SN  - 1752-6116 (Onlineausgabe)
SN  - 1476-3141 (Druckausgabe)
VL  - 21
IS  - 10
SP  - 1200
EP  - 1223
PB  - Taylor & Francis
CY  - London
ER  - 
TY  - JOUR
A1  - Angermann, Susanne
A1  - Günthner, Roman
A1  - Hanssen, Henner
A1  - Lorenz, Georg
A1  - Braunisch, Matthias C.
A1  - Steubl, Dominik
A1  - Matschkal, Julia
A1  - Kemmner, Stephan
A1  - Hausinger, Renate
A1  - Block, Zenonas
A1  - Haller, Bernhard
A1  - Heemann, Uwe
A1  - Kotliar, Konstantin
A1  - Grimmer, Timo
A1  - Schmaderer, Christoph
T1  - Cognitive impairment and microvascular function in end-stage renal disease
JF  - International Journal of Methods in Psychiatric Research (MPR)
N2  - Objective
Hemodialysis patients show an approximately threefold higher prevalence of cognitive impairment compared to the age-matched general population. Impaired microcirculatory function is one of the assumed causes. Dynamic retinal vessel analysis is a quantitative method for measuring neurovascular coupling and microvascular endothelial function. We hypothesize that cognitive impairment is associated with altered microcirculation of retinal vessels.

Methods
152 chronic hemodialysis patients underwent cognitive testing using the Montreal Cognitive Assessment. Retinal microcirculation was assessed by Dynamic Retinal Vessel Analysis, which carries out an examination recording retinal vessels' reaction to a flicker light stimulus under standardized conditions.

Results
In unadjusted as well as in adjusted linear regression analyses a significant association between the visuospatial executive function domain score of the Montreal Cognitive Assessment and the maximum arteriolar dilation as response of retinal arterioles to the flicker light stimulation was obtained.

Conclusion
This is the first study determining retinal microvascular function as surrogate for cerebral microvascular function and cognition in hemodialysis patients. The relationship between impairment in executive function and reduced arteriolar reaction to flicker light stimulation supports the involvement of cerebral small vessel disease as contributing factor for the development of cognitive impairment in this patient population and might be a target for noninvasive disease monitoring and therapeutic intervention.
KW  - cerebral small vessel disease
KW  - cognitive impairment
KW  - dialysis
KW  - retinal vessels
Y1  - 2022
U6  - https://doi.org/10.1002/mpr.1909
SN  - 1049-8931 (Print)
SN  - 1557-0657 (Online)
VL  - 31
IS  - 2
SP  - 1
EP  - 10
PB  - Wiley
ER  - 
TY  - JOUR
A1  - Kotliar, Konstantin
A1  - Ortner, Marion
A1  - Conradi, Anna
A1  - Hacker, Patricia
A1  - Hauser, Christine
A1  - Günthner, Roman
A1  - Moser, Michaela
A1  - Muggenthaler, Claudia
A1  - Diehl-Schmid, Janine
A1  - Priller, Josef
A1  - Schmaderer, Christoph
A1  - Grimmer, Timo
T1  - Altered retinal cerebral vessel oscillation frequencies in Alzheimer's disease compatible with impaired amyloid clearance
JF  - Neurobiology of Aging
N2  - Retinal vessels are similar to cerebral vessels in their structure and function. Moderately low oscillation frequencies of around 0.1 Hz have been reported as the driving force for paravascular drainage in gray matter in mice and are known as the frequencies of lymphatic vessels in humans. We aimed to elucidate whether retinal vessel oscillations are altered in Alzheimer's disease (AD) at the stage of dementia or mild cognitive impairment (MCI). Seventeen patients with mild-to-moderate dementia due to AD (ADD); 23 patients with MCI due to AD, and 18 cognitively healthy controls (HC) were examined using Dynamic Retinal Vessel Analyzer. Oscillatory temporal changes of retinal vessel diameters were evaluated using mathematical signal analysis. Especially at moderately low frequencies around 0.1 Hz, arterial oscillations in ADD and MCI significantly prevailed over HC oscillations and correlated with disease severity. The pronounced retinal arterial vasomotion at moderately low frequencies in the ADD and MCI groups would be compatible with the view of a compensatory upregulation of paravascular drainage in AD and strengthen the amyloid clearance hypothesis.
KW  - Alzheimer's disease
KW  - Retinal vessel analysis
KW  - Vasomotions
KW  - Pulsations
KW  - Mild cognitive impairment
Y1  - 2022
U6  - https://doi.org/10.1016/j.neurobiolaging.2022.08.012
SN  - 0197-4580
VL  - 120
SP  - 117
EP  - 127
PB  - Elsevier
CY  - Amsterdam
ER  -