TY - CHAP A1 - Souza Jr., Luis Antonio de A1 - Hook, Christian A1 - Papa, João Paulo A1 - Palm, Christoph T1 - Barrett's Esophagus Analysis Using SURF Features T2 - Bildverarbeitung für die Medizin 2017; Algorithmen - Systeme - Anwendungen. Proceedings des Workshops vom 12. bis 14. März 2017 in Heidelberg N2 - The development of adenocarcinoma in Barrett’s esophagus is difficult to detect by endoscopic surveillance of patients with signs of dysplasia. Computer assisted diagnosis of endoscopic images (CAD) could therefore be most helpful in the demarcation and classification of neoplastic lesions. In this study we tested the feasibility of a CAD method based on Speeded up Robust Feature Detection (SURF). A given database containing 100 images from 39 patients served as benchmark for feature based classification models. Half of the images had previously been diagnosed by five clinical experts as being ”cancerous”, the other half as ”non-cancerous”. Cancerous image regions had been visibly delineated (masked) by the clinicians. SURF features acquired from full images as well as from masked areas were utilized for the supervised training and testing of an SVM classifier. The predictive accuracy of the developed CAD system is illustrated by sensitivity and specificity values. The results based on full image matching where 0.78 (sensitivity) and 0.82 (specificity) were achieved, while the masked region approach generated results of 0.90 and 0.95, respectively. KW - Speiseröhrenkrankheit KW - Diagnose KW - Maschinelles Sehen KW - Automatische Klassifikation Y1 - 2017 U6 - https://doi.org/10.1007/978-3-662-54345-0_34 SP - 141 EP - 146 PB - Springer CY - Berlin ER - TY - JOUR A1 - Souza Jr., Luis Antonio de A1 - Mendel, Robert A1 - Strasser, Sophia A1 - Ebigbo, Alanna A1 - Probst, Andreas A1 - Messmann, Helmut A1 - Papa, João Paulo A1 - Palm, Christoph T1 - Convolutional Neural Networks for the evaluation of cancer in Barrett’s esophagus: Explainable AI to lighten up the black-box JF - Computers in Biology and Medicine N2 - Even though artificial intelligence and machine learning have demonstrated remarkable performances in medical image computing, their level of accountability and transparency must be provided in such evaluations. The reliability related to machine learning predictions must be explained and interpreted, especially if diagnosis support is addressed. For this task, the black-box nature of deep learning techniques must be lightened up to transfer its promising results into clinical practice. Hence, we aim to investigate the use of explainable artificial intelligence techniques to quantitatively highlight discriminative regions during the classification of earlycancerous tissues in Barrett’s esophagus-diagnosed patients. Four Convolutional Neural Network models (AlexNet, SqueezeNet, ResNet50, and VGG16) were analyzed using five different interpretation techniques (saliency, guided backpropagation, integrated gradients, input × gradients, and DeepLIFT) to compare their agreement with experts’ previous annotations of cancerous tissue. We could show that saliency attributes match best with the manual experts’ delineations. Moreover, there is moderate to high correlation between the sensitivity of a model and the human-and-computer agreement. The results also lightened that the higher the model’s sensitivity, the stronger the correlation of human and computational segmentation agreement. We observed a relevant relation between computational learning and experts’ insights, demonstrating how human knowledge may influence the correct computational learning. KW - Deep Learning KW - Künstliche Intelligenz KW - Computerunterstützte Medizin KW - Barrett's esophagus KW - Adenocarcinoma KW - Machine learning KW - Explainable artificial intelligence KW - Computer-aided diagnosis Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-20126 SN - 0010-4825 VL - 135 SP - 1 EP - 14 PB - Elsevier ER - TY - JOUR A1 - Souza Jr., Luis Antonio de A1 - Pacheco, André G.C. A1 - Passos, Leandro A. A1 - Santana, Marcos Cleison S. A1 - Mendel, Robert A1 - Ebigbo, Alanna A1 - Probst, Andreas A1 - Messmann, Helmut A1 - Palm, Christoph A1 - Papa, João Paulo T1 - DeepCraftFuse: visual and deeply-learnable features work better together for esophageal cancer detection in patients with Barrett’s esophagus JF - Neural Computing and Applications N2 - Limitations in computer-assisted diagnosis include lack of labeled data and inability to model the relation between what experts see and what computers learn. Even though artificial intelligence and machine learning have demonstrated remarkable performances in medical image computing, their accountability and transparency level must be improved to transfer this success into clinical practice. The reliability of machine learning decisions must be explained and interpreted, especially for supporting the medical diagnosis. While deep learning techniques are broad so that unseen information might help learn patterns of interest, human insights to describe objects of interest help in decision-making. This paper proposes a novel approach, DeepCraftFuse, to address the challenge of combining information provided by deep networks with visual-based features to significantly enhance the correct identification of cancerous tissues in patients affected with Barrett’s esophagus (BE). We demonstrate that DeepCraftFuse outperforms state-of-the-art techniques on private and public datasets, reaching results of around 95% when distinguishing patients affected by BE that is either positive or negative to esophageal cancer. KW - Deep Learning KW - Speiseröhrenkrebs KW - Adenocarcinom KW - Endobrachyösophagus KW - Diagnose KW - Maschinelles Lernen KW - Machine learning KW - Adenocarcinoma KW - Object detector KW - Barrett’s esophagus KW - Deep Learning Y1 - 2024 U6 - https://doi.org/10.1007/s00521-024-09615-z VL - 36 SP - 10445 EP - 10459 PB - Springer CY - London ER - TY - JOUR A1 - Souza Jr., Luis Antonio de A1 - Palm, Christoph A1 - Mendel, Robert A1 - Hook, Christian A1 - Ebigbo, Alanna A1 - Probst, Andreas A1 - Messmann, Helmut A1 - Weber, Silke A. T. A1 - Papa, João Paulo T1 - A survey on Barrett's esophagus analysis using machine learning JF - Computers in Biology and Medicine N2 - This work presents a systematic review concerning recent studies and technologies of machine learning for Barrett's esophagus (BE) diagnosis and treatment. The use of artificial intelligence is a brand new and promising way to evaluate such disease. We compile some works published at some well-established databases, such as Science Direct, IEEEXplore, PubMed, Plos One, Multidisciplinary Digital Publishing Institute (MDPI), Association for Computing Machinery (ACM), Springer, and Hindawi Publishing Corporation. Each selected work has been analyzed to present its objective, methodology, and results. The BE progression to dysplasia or adenocarcinoma shows a complex pattern to be detected during endoscopic surveillance. Therefore, it is valuable to assist its diagnosis and automatic identification using computer analysis. The evaluation of the BE dysplasia can be performed through manual or automated segmentation through machine learning techniques. Finally, in this survey, we reviewed recent studies focused on the automatic detection of the neoplastic region for classification purposes using machine learning methods. KW - Speiseröhrenkrankheit KW - Diagnose KW - Mustererkennung KW - Maschinelles Lernen KW - Literaturbericht KW - Barrett's esophagus KW - Machine learning KW - Adenocarcinoma KW - Image processing KW - Pattern recognition KW - Computer-aided diagnosis Y1 - 2018 U6 - https://doi.org/10.1016/j.compbiomed.2018.03.014 VL - 96 SP - 203 EP - 213 PB - Elsevier ER - TY - CHAP A1 - Souza Jr., Luis Antonio de A1 - Passos, Leandro A. A1 - Mendel, Robert A1 - Ebigbo, Alanna A1 - Probst, Andreas A1 - Messmann, Helmut A1 - Palm, Christoph A1 - Papa, João Paulo T1 - Fine-tuning Generative Adversarial Networks using Metaheuristics BT - A Case Study on Barrett's Esophagus Identification T2 - Bildverarbeitung für die Medizin 2021. Proceedings, German Workshop on Medical Image Computing, Regensburg, March 7-9, 2021 N2 - Barrett's esophagus denotes a disorder in the digestive system that affects the esophagus' mucosal cells, causing reflux, and showing potential convergence to esophageal adenocarcinoma if not treated in initial stages. Thus, fast and reliable computer-aided diagnosis becomes considerably welcome. Nevertheless, such approaches usually suffer from imbalanced datasets, which can be addressed through Generative Adversarial Networks (GANs). Such techniques generate realistic images based on observed samples, even though at the cost of a proper selection of its hyperparameters. Many works employed a class of nature-inspired algorithms called metaheuristics to tackle the problem considering distinct deep learning approaches. Therefore, this paper's main contribution is to introduce metaheuristic techniques to fine-tune GANs in the context of Barrett's esophagus identification, as well as to investigate the feasibility of generating high-quality synthetic images for early-cancer assisted identification. KW - Endoskopie KW - Computerunterstützte Medizin KW - Deep Learning Y1 - 2021 SN - 978-3-658-33197-9 U6 - https://doi.org/10.1007/978-3-658-33198-6_50 SP - 205 EP - 210 PB - Springer Vieweg CY - Wiesbaden ER - TY - JOUR A1 - Souza Jr., Luis Antonio de A1 - Passos, Leandro A. A1 - Santana, Marcos Cleison S. A1 - Mendel, Robert A1 - Rauber, David A1 - Ebigbo, Alanna A1 - Probst, Andreas A1 - Messmann, Helmut A1 - Papa, João Paulo A1 - Palm, Christoph T1 - Layer-selective deep representation to improve esophageal cancer classification JF - Medical & Biological Engineering & Computing N2 - Even though artificial intelligence and machine learning have demonstrated remarkable performances in medical image computing, their accountability and transparency level must be improved to transfer this success into clinical practice. The reliability of machine learning decisions must be explained and interpreted, especially for supporting the medical diagnosis.For this task, the deep learning techniques’ black-box nature must somehow be lightened up to clarify its promising results. Hence, we aim to investigate the impact of the ResNet-50 deep convolutional design for Barrett’s esophagus and adenocarcinoma classification. For such a task, and aiming at proposing a two-step learning technique, the output of each convolutional layer that composes the ResNet-50 architecture was trained and classified for further definition of layers that would provide more impact in the architecture. We showed that local information and high-dimensional features are essential to improve the classification for our task. Besides, we observed a significant improvement when the most discriminative layers expressed more impact in the training and classification of ResNet-50 for Barrett’s esophagus and adenocarcinoma classification, demonstrating that both human knowledge and computational processing may influence the correct learning of such a problem. KW - Multistep training KW - Barrett’s esophagus detection KW - Convolutional neural networks KW - Deep learning Y1 - 2024 U6 - https://doi.org/10.1007/s11517-024-03142-8 VL - 62 SP - 3355 EP - 3372 PB - Springer Nature CY - Heidelberg ER - TY - CHAP A1 - Souza, Luis A. A1 - Pacheco, André G.C. A1 - de Angelo, Gabriel G. A1 - Oliveira-Santos, Thiago A1 - Palm, Christoph A1 - Papa, João Paulo T1 - LiwTERM: A Lightweight Transformer-Based Model for Dermatological Multimodal Lesion Detection T2 - 2024 37th SIBGRAPI Conference on Graphics, Patterns and Images (SIBGRAPI), Manaus, Brazil, 9/30/2024 - 10/3/2024 N2 - Skin cancer is the most common type of cancer in the world, accounting for approximately 30% of all diagnosed tumors. Early diagnosis reduces mortality rates and prevents disfiguring effects in different body regions. In recent years, machine learning techniques, particularly deep learning, have shown promising results in this task, presenting studies that have demonstrated that combining a patient’s clinical information with images of the lesion is crucial for improving the classification of skin lesions. Despite that, meaningful use of clinical information with multiple images is mandatory, requiring further investigation. Thus, this project aims to contribute to developing multimodal machine learning-based models to cope with the skin lesion classification task employing a lightweight transformer model. As a main hypothesis, models can take multiple images from different sources as input, along with clinical information from the patient’s history, leading to a more reliable diagnosis. Our model deals with the not-trivial task of combining images and clinical information (from anamneses) concerning the skin lesions in a lightweight transformer architecture that does not demand high computation resources but still presents competitive classification results. KW - Lightweight Architectures KW - Trans- formers KW - Skin Lesion Detection KW - Deep learning Y1 - 2024 SN - 979-8-3503-7603-6 U6 - https://doi.org/10.1109/SIBGRAPI62404.2024.10716324 SP - 1 EP - 6 PB - IEEE ER - TY - JOUR A1 - Souza, Luis A. A1 - Pacheco, André G.C. A1 - de Souza, Alberto F. A1 - Oliveira-Santos, Thiago A1 - Badue, Claudine A1 - Palm, Christoph A1 - Papa, João Paulo T1 - TransConv: a lightweight architecture based on transformers and convolutional neural networks for adenocarcinoma and Barrett’s esophagus identification JF - Neural Computing and Applications N2 - Barrett’s esophagus, also known as BE, is commonly associated with repeated exposure to stomach acid. If not treated properly, it may evolve into esophageal adenocarcinoma, aka esophageal cancer. This paper proposes TransConv, a hybrid architecture that benefits from features learned by pre-trained vision transformers (ViTs) and convolutional neural networks (CNNs), followed by a shallow neural network composed of three normalizations, ReLU activations, and fully connected layers, and a SoftMax head to distinguish between BE and esophageal cancer. TransConv is designed to be training-lightweight, and for the ViT and CNN backbone models, weights are kept frozen during training, i.e., the primary goal of TransConv is to learn the weights of the fully connected layer from both backbones only, avoiding the burden of updating their weights but still learning their final descriptions for the lightweight convolutional model. We report promising results with low computational training costs in two datasets, one public and another private. From our achievements, TransConv was able to deliver balanced accuracy results around 85% and 86% for each evaluated dataset, respectively, in a design that required only 50 epochs of model training, a very reduced number compared to state-of-the-art conducted studies in the same domain. Y1 - 2025 U6 - https://doi.org/10.1007/s00521-025-11299-y IS - 37 SP - 15535 EP - 15546 PB - Springer ER - TY - JOUR A1 - Spiller, Ralf A1 - Degen, Matthias A1 - Kronewald, Elke A1 - Guertler, Katherine T1 - Media watchblogs as an instrument of media accountability: An international survey JF - Journal of Applied Journalism & Media Studies N2 - Media watchdog weblogs can play an important role in media accountability, provided that the bloggers are regularly active and have an appropriate awareness of their role in the media landscape. The following article examines the presence and influence of media watchblogs in selected nations, as well as the operators’ standards and perceptions of their roles. In semi-structured qualitative interviews, operators of watchblogs in Germany, Austria, Switzerland and the United Kingdom discussed their perceptions of their role, their ethical guidelines, their financing and any conflicts of interest, and their projections for the future. The interviews reveal that most media watchbloggers do not interpret their role to be a Fifth Estate with a mandate to monitor the mass media. The watchbloggers are reluctant to accept and uphold formal ethical and quality criteria, and limitations on time and money make them unable to guarantee ongoing critical media analysis. For these reasons, media watchblogs are determined to be a weak instrument of media accountability. KW - ethics KW - expert interviews KW - international comparative study KW - media accountability KW - role identity KW - watchblogs Y1 - 2016 U6 - https://doi.org/10.1386/ajms.5.2.151_1 SN - 2049-9531 VL - 5 IS - 2 SP - 151 EP - 176 PB - intellect ER - TY - CHAP A1 - Spychalski, Dominik A1 - Rode, Olaf A1 - Ritthaler, Markus A1 - Raptis, Georgios T1 - Conceptual Design and Analysis of a Mobile Digital Identity for eHealth Applications T2 - 2021 IEEE EMBS International Conference on Biomedical and Health Informatics (BHI): 27-30 July 2021, Athens, Greece N2 - As mobile technology continues to improve, more and more professional services are being offered as mobile apps. This paradigm shift also affects eHealth applications. Digital identities in nation-wide eHealth infrastructures are often realized via smart cards, which however, do not support mobile applications well. In this paper we propose a concept of a mobile eID for eHealth based on smartphones with embedded secure hardware, an mobile authenticator app and an account manager as well as an Identity Provider (IdP) as backend services. The practical applicability of the concept is shown using the example of the German eHealth infrastructure. Our method generates a cryptographic key pair in secure hardware on the user’s smartphone, registers it on the IdP and uses it to authenticate on the IdP. The security of the private key and the integrity of the smartphone is also validated and attestated. The user’s established smartcard-based identity "Electronic Health Card" (EHC) forms the trust anchor. To authenticate against specialist eHealth apps the IdP issues standard-compliant OAuth2.0/OIDC tokens with a limited period of validity. Furthermore, in our security analysis we demonstrate that based on specific security requirements for smartphones and operating systems, at least the eIDAS security level "substantial" related to the technical security aspects of the system can be achieved. On the basis of this research German legislation was adjusted and "digital identities" supplementary to the smartcard-based EHC will be issued from 2023 in the German eHealth infrastructure. KW - digital identity KW - mobile security KW - eHealth KW - authentication scheme KW - identity management Y1 - 2021 U6 - https://doi.org/10.1109/BHI50953.2021.9508554 SN - 2641-3604 SP - 1 EP - 4 PB - IEEE ER - TY - JOUR A1 - Stadler, Sebastian A1 - Cornet, Henriette A1 - Frenkler, Fritz T1 - Assessing Heuristic Evaluation in Immersive Virtual Reality: A Case Study on Future Guidance Systems JF - Multimodal Technologies and Interaction N2 - A variety of evaluation methods for user interfaces (UI) exist such as usability testing, cognitive walkthrough, and heuristic evaluation. However, UIs such as guidance systems at transit hubs must be evaluated in their intended application field to allow the effective and valid identification of usability flaws. However, what if evaluations are not feasible in real environments, or laboratorial conditions cannot be ensured? Based on adapted heuristics, in the present study, the method of heuristic evaluation is combined with immersive Virtual Reality (VR) for the identification of usability flaws of dynamic guidance systems (DGS) at transit hubs. The study involved usability evaluations of nine DGS concepts using the newly proposed method. The results show that compared to computer-based heuristic evaluations, the use of immersive VR led to the identification of an increased amount of “severe” usability flaws as well as overall usability flaws. Within a qualitative assessment, immersive VR is validated as a suitable tool for conducting heuristic evaluations involving significant advantages such as the creation of realistic experiences in laboratorial conditions. Future work seeks to further prove the suitability of using immersive VR for heuristic evaluations and compare the proposed method to other evaluative methods. KW - virtual reality KW - heuristic evaluation KW - human-computer interaction KW - user interfaces KW - guidance system Y1 - 2023 U6 - https://doi.org/10.3390/mti7020019 SN - 2414-4088 VL - 7 IS - 2 ER - TY - JOUR A1 - Steiger, Tamara A1 - Foltan, Maik A1 - Philipp, Alois A1 - Müller, Thomas A1 - Gruber, Michael A1 - Bredthauer, Andre A1 - Krenkel, Lars A1 - Birkenmaier, Clemens A1 - Lehle, Karla T1 - Accumulations of von Willebrand factor within ECMO oxygenators: Potential indicator of coagulation abnormalities in critically ill patients? JF - Artificial Organs N2 - Clot formation within membrane oxygenators (MOs) remains a critical problem during extracorporeal membrane oxygenation (ECMO). The composition of the clots-in particular, the presence of von Willebrand factor (vWF)-may be an indicator for prevalent nonphysiological flow conditions, foreign body reactions, or coagulation abnormalities in critically ill patients. Mats of interwoven gas exchange fibers from randomly collected MOs (PLS, Maquet, Rastatt, Germany) of 21 patients were stained with antibodies (anti-vWF and anti-P-selectin) and counterstained with 4 ',6-diamidino-2-phenylindole. The extent of vWF-loading was correlated with patient and technical data. While 12 MOs showed low vWF-loadings, 9 MOs showed high vWF-loading with highest accumulations close to crossing points of adjacent gas fibers. The presence and the extent of vWF-fibers/"cobwebs," leukocytes, platelet-leukocyte aggregates (PLAs), and P-selectin-positive platelet aggregates were independent of the extent of vWF-loading. However, the highly loaded MOs were obtained from patients with a significantly elevated SOFA score, severe thrombocytopenia, and persistent liver dysfunction. The coagulation abnormalities of these critically ill patients may cause an accumulation of the highly thrombogenic and elongated high-molecular-weight vWF multimers in the plasma which will be trapped in the MOs during the ECMO therapy. KW - ECMO KW - PLATELET ACTIVATION KW - THROMBOSIS KW - BLOOD FLOW KW - INFLAMMATION Y1 - 2019 U6 - https://doi.org/10.1111/aor.13513 SN - 1525-1594 VL - 43 IS - 11 SP - 1065 EP - 1076 PB - Wiley CY - Hoboken ER - TY - JOUR A1 - Stelzer, Vera A1 - Krenkel, Lars T1 - 2D numerical investigations derived from a 3D dragonfly wing captured with a high-resolution micro-CT JF - Technology and health care : official journal of the European Society for Engineering and Medicine N2 - BACKGROUND: Due to their corrugated profile, dragonfly wings have special aerodynamic characteristics during flying and gliding. OBJECTIVE: The aim of this study was to create a realistic 3D model of a dragonfly wing captured with a high-resolution micro-CT. To represent geometry changes in span and chord length and their aerodynamic effects, numerical investigations are carried out at different wing positions. METHODS: The forewing of a Camacinia gigantea was captured using a micro-CT. After the wing was adapted an error-free 3D model resulted. The wing was cut every 5 mm and 2D numerical analyses were conducted in Fluent® 2020 R2 (ANSYS, Inc., Canonsburg, PA, USA). RESULTS: The highest lift coefficient, as well as the highest lift-to-drag ratio, resulted at 0 mm and an angle of attack (AOA) of 5∘. At AOAs of 10∘ or 15∘, the flow around the wing stalled and a Kármán vortex street behind the wing becomes CONCLUSIONS: The velocity is higher on the upper side of the wing compared to the lower side. The pressure acts vice versa. Due to the recirculation zones that are formed in valleys of the corrugation pattern the wing resembles the form of an airfoil. KW - aerodynamics KW - computational fluid dynamics KW - Dragonfly wing KW - gliding flight KW - insect flight Y1 - 2022 U6 - https://doi.org/10.3233/THC-219010 N1 - Corresponding author: Vera Stelzer VL - 30 IS - 1 SP - 283 EP - 289 PB - IOS Press ER - TY - CHAP A1 - Stelzer, Vera A1 - Tauwald, Sandra Melina A1 - Vielsmeier, Veronika A1 - Cieplik, Fabian A1 - Kandulski, Arne A1 - Schneider-Brachert, Wulf A1 - Wünsch, Olaf A1 - Rütten, Markus A1 - Krenkel, Lars ED - Dillman, Andreas ED - Heller, Gerd ED - Kraemer, Ewald ED - Wagner, Claus ED - Weiss, Julien T1 - Generation and Distribution of Surgical Smoke During High Frequency Electrocauterization T2 - New Results in Numerical and Experimental Fluid Mechanics XIV. STAB/DGLR Symposium 2022 N2 - Surgical Smoke is generated during the cauterization of tissue with high-frequency (HF) devices and consists of 95% water vapor and 5% cellular debris. When the coagulation tweezers, which are supplied with HF voltage by the HF device, touch tissue, the electric circuit is closed, and smoke is generated by the heat. In-vivo investigations are performed during tracheotomies where surgical smoke is produced during coagulation of tissue. Furthermore, in-vitro parametric studies to investigate the particle number and size distribution and the spatial distribution of surgical smoke with laser light sheet technique are conducted. With higher power of the HF device, the particles generated are larger in size and the total number of particles generated is also higher. Adding artificial saliva to the tissue shows even higher particle counts. The study by laser light sheet also confirms this. The resulting characteristic size distribution, which may include viruses and bacterial components, confirms considering the risk arising from surgical smoke. Furthermore, the experiments will provide the database for further numerical investigations. KW - Surgical smoke KW - Fluid Mechanics KW - Aerosols KW - Tracheotomies Y1 - 2023 SN - 978-3-031-40481-8 U6 - https://doi.org/10.1007/978-3-031-40482-5_53 SP - 559 EP - 568 PB - Springer Nature Switzerland AG CY - Cham, Switzerland ER - TY - JOUR A1 - Strech, Daniel A1 - Follmann, Markus A1 - Klemperer, David A1 - Lelgemann, Monika A1 - Ollenschläger, Günter A1 - Raspe, Heiner A1 - Nothacker, Monika T1 - When Choosing Wisely meets clinical practice guidelines JF - Zeitschrift für Evidenz, Fortbildung und Qualität im Gesundheitswesen : ZEFQ = The journal of evidence and quality in health care N2 - The American Board of Internal Medicine (ABIM) Foundation launched the Choosing Wisely campaign in 2012 and until today convinced more than 50 US specialist societies to develop lists of interventions that may not improve people’s health but are potentially harmful. We suggest combining these new efforts with the already existing efforts in clinical practice guideline development. Existing clinical practice guidelines facilitate a more participatory and evidence-based approach to the development of top 5 lists. In return, adding top 5 lists (for overuse and underuse) to existing clinical practice guidelines nicely addresses a neglected dimension to clinical practice guideline development, namely explicit information on which Do or Don’t do recommendations are frequently disregarded in practice. T2 - Wenn "Choosing Wisely" auf Leitlinien trifft Y1 - 2014 U6 - https://doi.org/10.1016/j.zefq.2014.10.014 SN - 1865-9217 SN - 2212-0289 VL - 108 IS - 10 SP - 601 EP - 603 PB - Elsevier ER - TY - CHAP A1 - Suess, Franz A1 - Melzner, Maximilian A1 - Dendorfer, Sebastian T1 - Towards ergonomics working - machine learning algorithms and musculoskeletal modeling T2 - IOP Conference Series: Materials Science and Engineering N2 - Ergonomic workplaces lead to fewer work-related musculoskeletal disorders and thus fewer sick days. There are various guidelines to help avoid harmful situations. However, these recommendations are often rather crude and often neglect the complex interaction of biomechanical loading and psychological stress. This study investigates whether machine learning algorithms can be used to predict mechanical and stress-related muscle activity for a standardized motion. For this purpose, experimental data were collected for trunk movement with and without additional psychological stress. Two different algorithms (XGBoost and TensorFlow) were used to model the experimental data. XGBoost in particular predicted the results very well. By combining it with musculoskeletal models, the method shown here can be used for workplace analysis but also for the development of real-time feedback systems in real workplace environments. Y1 - 2021 U6 - https://doi.org/10.1088/1757-899X/1208/1/012001 SN - 1757-899X N1 - Corresponding author: Sebastian Dendorfer VL - 1208 PB - IOP Publishing ER - TY - JOUR A1 - Süzeroglu-Melchiors, Sevim A1 - Gassmann, Oliver A1 - Palmié, Maximilian T1 - Friend or foe? The effects of patent attorney use on filing strategy vis-a-vis the effects of firm experience JF - Management Decision N2 - PurposeIn the intellectual property (IP) and management literature, the question of how external patent attorneys impact patent filings has been understudied. The purpose of this paper is to advance this area of research by examining how the use of external patent attorneys influences the patent filing strategies of firms and what impact firms? level of experience with the exclusive use of in-house resources has on filing strategies. This study, thus, provides insights into the strategic dimension behind patent filing, a process which is affected by patent attorneys? work and decision-making processes.Design/methodology/approachThe econometric analysis is based on a patent database of 922,553 patents which is combined with an EPO patent database covering applications from 1990 to 2010. The authors test the hypotheses for this study using patent indicators addressing the impact of in-house firm experience vs the use of external patent attorneys on firm?s filing strategy.FindingsThis research finds empirical evidence that external patent attorneys? work has an effect on patent scope, international scope, and patenting speed. Moreover, it can be shown that external patent attorneys have a positive impact on most filing dimensions, such as patent scope, international scope and the Patent Cooperation Treaty option, whereas the level of in-house firm experience has a negative impact on most filing dimensions. This implies that external patent attorneys seem to pursue a ?maximization approach? while experienced firms seem to pursue a more differentiated approach to filing patents, for instance, drafting narrower and more focused patents.Practical implicationsThe study suggests that effective filing strategies require an integrated approach between diverse IP stakeholders. More particularly, filing strategies should be communicated and aligned between all actors, including external patent attorneys in order to achieve the targeted patenting output.Originality/valueThe current study develops a patent filing typology, which accounts for patent attorneys? decision options. In providing insights into patent attorneys? work and their impacts on intellectual property rights management, the study is a useful complement to prior research, which has predominantly focused on applicants or examiners. KW - Patents KW - Filing strategy KW - Intellectual property management KW - IP Intermediaries KW - Patent attorney KW - Patent strategies KW - Strategic IP mnanagement Y1 - 2017 U6 - https://doi.org/10.1108/MD-01-2016-0047 SN - 0025-1747 VL - 55 IS - 6 SP - 1122 EP - 1142 PB - Emerald ER - TY - JOUR A1 - Süzeroğlu-Melchiors, Sevim T1 - The supply side of IP management: Understanding firms’ choices regarding IP intermediaries JF - World Patent Information N2 - Studies focusing on the supply side of IP management, particularly on the outsourcing of patent related work, are relatively rare. This paper aims to contribute to the IP literature in two ways. First, a definition of the IP service provider is proposed. Second, I consider three main hypotheses that determine a firm's preference for outsourced IP work. Using data on the outsourcing of patent renewal payments, I found evidence that the choice of IP supplier is affected by: (1) the firm's own IP maintenance capabilities, (2) the firm's IP knowledge utilization, and (3) the IP complexity. KW - Intellectual property (IP) management KW - IP intermediaries KW - IP suppliers KW - Patents Y1 - 2017 U6 - https://doi.org/10.1016/j.wpi.2017.08.002 SN - 0172-2190 VL - 50 SP - 55 EP - 63 PB - Elsevier ER - TY - JOUR A1 - Tauwald, Sandra Melina A1 - Erzinger, Florian A1 - Quadrio, Maurizio A1 - Rütten, Markus A1 - Stemmer, Christian A1 - Krenkel, Lars T1 - Tomo-PIV in a patient-specific model of human nasal cavities: a methodological approach JF - Measurement Science and Technology N2 - The human nose serves as the primary gateway for air entering the respiratory system and plays a vital role in breathing. Nasal breathing difficulties are a significant health concern, leading to substantial healthcare costs for patients. Understanding nasal airflow dynamics is crucial for comprehending respiratory mechanisms. This article presents a detailed study using tomo-Particle Image Velocimetry (PIV) to investigate nasal airflow dynamics while addressing its accuracy. Embedded in the OpenNose project, the work described aims to provide a validation basis for different numerical approaches to upper airway flow. The study includes the manufacturing of a transparent silicone model based on a clinical CT scan, refractive index matching to minimize optical distortions, and precise flow rate adjustments based on physiological breathing cycles. This method allows for spatial high-resolution investigations in different regions of interest within the nasopharynx during various phases of the breathing cycle. The results demonstrate the accuracy of the investigations, enabling detailed analysis of flow structures and gradients. This spatial high-resolution tomo-PIV approach provides valuable insights into the complex flow phenomena occurring during the physiological breathing cycle in the nasopharynx. The study's findings contribute to advancements in non-free-of-sight experimental flow investigation of complex cavities under nearly realistic conditions. Furthermore, reliable and accurate experimental data is crucial for properly validating numerical approaches that compute this patient-specific flow for clinical purposes. Y1 - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-70393 N1 - Corresponding author: Sandra Melina Tauwald VL - 35 IS - 5 PB - IOP Publishing ER - TY - JOUR A1 - Tauwald, Sandra Melina A1 - Michel, Johanna A1 - Brandt, Marie A1 - Vielsmeier, Veronika A1 - Stemmer, Christian A1 - Krenkel, Lars T1 - Experimental studies and mathematical modeling of the viscoelastic rheology of tracheobronchial mucus from respiratory healthy patients JF - Multidisciplinary Respiratory Medicine N2 - 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. KW - tracheobronchial mucus KW - rheological model KW - viscoelasticity Y1 - 2023 U6 - https://doi.org/10.4081/mrm.2023.923 SN - 2049-6958 N1 - Corresponding author: Sandra Melina Tauwald VL - 18 IS - 1 PB - PAGEPress CY - Pavia, Italy ER - TY - CHAP A1 - Tauwald, Sandra Melina A1 - Quadrio, Maurizio A1 - Rütten, Markus A1 - Stemmer, Christian A1 - Krenkel, Lars T1 - High Spatial Resolution Tomo-PIV of the Trachea Focussing on the Physiological Breathing Cycle T2 - New Results in Numerical and Experimental Fluid Mechanics XIV - Contributions to the 23nd STAB/DGLR Symposium N2 - Investigations of complex patient-specific flow in the nasopharynx requires high resolution numerical calculations validated by reliable experiments. When building the validation base and the benchmark of computational fluid dynamics, an experimental setup of the nasal airways was developed. The applied optical measurement technique of tomo-PIV supplies information on the governing flow field in three dimensions. This paper presents tomo-PIV measurements of the highly complex patient-specific geometry of the human trachea. A computertomographic scan of a person’s head builds the basis of the experimental silicone model of the nasal airways. An optimised approach for precise refractive index matching avoids optical distortions even in highly complex non-free-of-sight 3D geometries. A linear-motor-driven pump generates breathing scenarios, based on measured breathing cycles. Adjusting of the CCD cameras‘ double-frame-rate PIV-Δt enables the detailed analysis of flow structures during different cycle phases. Merging regions of interest enables high spatial resolution acquisition of the flow field. KW - Tomographic PIV KW - Flow visualisation KW - Breathing cycle KW - Nasal airflow Y1 - 2023 N1 - Accepted for publication, not yet published PB - Springer ER - TY - CHAP A1 - Tomer, Amir A1 - Hagel, Georg A1 - Mottok, Jürgen A1 - Alt, Dorit A1 - Barak, Miriam I. A1 - Hadar, Irit T1 - CAPELLA: A conceptual framework for adaptive life-long learning T2 - IEEE Global Engineering Education Conference (EDUCON), 25-28 April 2017, Athens, Greece N2 - In this paper we describe a proposed framework for Cooperative Adaptive Personalized Education for Life-long Learning and Activation (CAPELLA). CAPELLA comprises four models: A Knowledge Organization Model, a Learning Process Model, a Community Collaboration Model and a Gaming Model. The underlying pedagogical approach is based on the four pillars of learning: Learning to know, learning to do, learning to collaborate and learning to be. Based on these models and principles, CAPELLA provides a theoretical framework that may assist IT developers to develop state-of-the-art educational platforms and advanced learning applications. Using an example of a UML Diagramming Workshop we demonstrate how CAPELLA incorporates the principles of Adaptive Learning. Y1 - 2017 U6 - https://doi.org/10.1109/EDUCON.2017.7943041 SP - 1463 EP - 1472 ER - TY - GEN A1 - Treutwein, Marius A1 - Hipp, Matthias A1 - Löschel, Rainer A1 - Kölbl, Oliver A1 - Dobler, Barbara T1 - Second cancer risk after radiation of localized prostate cancer with and without flattening filter T2 - Radiotherapy and oncology Y1 - 2017 U6 - https://doi.org/10.1016/S0167-8140(17)32050-9 VL - 123 IS - 1 PB - Elsevier ER - TY - JOUR A1 - Treutwein, Marius A1 - Löschel, Rainer A1 - Hipp, Matthias A1 - Kölbl, Oliver A1 - Dobler, Barbara T1 - Secondary malignancy risk for patients with localized prostate cancer after intensity-modulated radiotherapy with and without flattening filter JF - The Journal of Applied Clinical Medical Physics (JACMP) N2 - Men treated for localized prostate cancer by radiotherapy have often a remaining life span of 10 yr or more. Therefore, the risk for secondary malignancies should be taken into account. Plans for ten patients were evaluated which had been performed on an Oncentra (R) treatment planning system for a treatment with an Elekta Synergy (TM) linac with Agility (TM) head. The investigated techniques involved IMRT and VMTA with and without flattening filter. Different dose response models were applied for secondary carcinoma and sarcoma risk in the treated region and also in the periphery. As organs at risk we regarded for carcinoma risk urinary bladder, rectum, colon, esophagus, thyroid, and for sarcoma risk bone and soft tissue. The excess absolute risk (EAR) was found very similar in the treated region for both techniques (IMRT and VMAT) and also for both with and without flattening filter. The secondary sarcoma risk resulted about one magnitude smaller than the secondary carcinoma risk. The EAR to the peripheral organs was statistically significant reduced by application of the flattening filter free mode concerning the flattening filter as main source of scattered dose. Application of flattening filter free mode can thus support to reduce second malignancy risk for patients with localized prostate cancer. KW - 2ND PRIMARY CANCERS KW - ARC THERAPY VMAT KW - BEAM KW - CARCINOMA KW - flattening filter free KW - IMPACT KW - IMRT KW - localized prostate cancer KW - PHOTON KW - RADIATION-THERAPY KW - RECTAL-CANCER KW - secondary malignancy risk KW - SOFT-TISSUE SARCOMA KW - VMAT Y1 - 2020 U6 - https://doi.org/10.1002/acm2.13088 VL - 21 IS - 12 SP - 197 EP - 205 PB - Wiley ER - TY - JOUR A1 - Treutwein, Marius A1 - Steger, Felix A1 - Löschel, Rainer A1 - Kölbl, Oliver A1 - Dobler, Barbara T1 - The influence of radiotherapy techniques on the plan quality and on the risk of secondary tumors in patients with pituitary adenoma JF - BMC cancer N2 - BACKGROUND: This planning study compares different radiotherapy techniques for patients with pituitary adenoma, including flatness filter free mode (FFF), concerning plan quality and secondary malignancies for potentially young patients. The flatness filter has been described as main source of photon scatter. MATERIAL AND METHODS: Eleven patients with pituitary adenoma were included. An Elekta Synergy™ linac was used in the treatment planning system Oncentra® and for the measurements. 3D plans, IMRT, and VMAT plans and non-coplanar varieties were considered. The plan quality was evaluated regarding homogeneity, conformity, delivery time and dose to the organs at risk. The secondary malignancy risk was calculated from dose volume data and from measured dose to the periphery using different models for carcinoma and sarcoma risk. RESULTS: The homogeneity and conformity were nearly unchanged with and without flattening filter, neither was the delivery time found substantively different. VMAT plans were more homogenous, conformal and faster in delivery than IMRT plans. The secondary cancer risk was reduced with FFF both in the treated region and in the periphery. VMAT plans resulted in a higher secondary brain cancer risk than IMRT plans, but the risk for secondary peripheral cancer was reduced. Secondary sarcoma risk plays a minor role. No advantage was found for non-coplanar techniques. The FFF delivery times were not shortened due to additional monitor units needed and technical limitations. The risk for secondary brain cancer seems to depend on the irradiated volume. Secondary sarcoma risk is much smaller than carcinoma risk in accordance to the results of the atomic bomb survivors. The reduction of the peripheral dose and resulting secondary malignancy risk for FFF is statistically significant. However, it is negligible in comparison to the risk in the treated region. CONCLUSION: Treatments with FFF can reduce secondary malignancy risk while retaining similar quality as with flattening filter and should be preferred. VMAT plans show the best plan quality combined with lowest peripheral secondary malignancy risk, but highest level of second brain cancer risk. Taking this into account VMAT FFF seems the most advantageous technique for the treatment of pituitary adenomas with the given equipment. KW - Adenoma/radiotherapy KW - Age Factors KW - Female KW - Humans KW - Male KW - Pituitary Neoplasms/radiotherapy KW - Radiotherapy Dosage KW - risk factors Y1 - 2020 U6 - https://doi.org/10.1186/s12885-020-6535-y VL - 20 SP - 1 EP - 13 PB - Springer ER - TY - JOUR A1 - Tröster, Mark A1 - Eckstein, Simon A1 - Kennel, Paula A1 - Kopp, Verna A1 - Benkiser, Alina A1 - Bihlmeier, Felicitas A1 - Daub, Urban A1 - Maufroy, Christophe A1 - Dendorfer, Sebastian A1 - Fritzsche, Lars A1 - Schneider, Urs A1 - Bauernhasl, Thomas T1 - Person-specific evaluation method for occupational exoskeletons - Biomechanical body heat map JF - Applied Ergonomics N2 - Human-centred and ergonomic work design is one of the most important drivers for increasing the competitiveness of the European Union. As a flexible, person-specific occupational measure, exoskeletons promise great potential for effectively reducing individual ergonomic stress. Digital human models can provide important insights and offer great potential for systematising the effect and targeted use of exoskeletons, supporting their effective implementation in practice. In this article, digital human models are applied on two levels. Firstly, a realistic industrial logistics scenario in which boxes had to be relocated is designed with the help of a digital human model for workplace and process planning and secondly, a new biomechanical evaluation methodology to analyse intended and unintended effects on internal stress on the human body is demonstrated by applying musculoskeletal exoskeleton human models of four test subjects. Finally, the modelled biomechanical support tendencies of one exoskeleton are preliminary validated using EMG measurement data of the back muscles collected from the four male workers. The preliminary analysis of two back-support exoskeletons to demonstrate the new methodological approach confirms the expected, intended effects in the lower back and reveals unintended effects, such as e.g. changes in knee kinetics when applying a soft or hard-frame exoskeleton. Furthermore, the exemplary results to demonstrate the methodological approach expose notable differences between the test subjects, which underlines the relevance of person-specific evaluation and consideration of exoskeleton support. The preliminary validation shows a correlation between the modelled and the EMG-measured biomechanical exoskeleton support of the considered back muscles. KW - Industry 5.0 KW - Ergonomics KW - Digital human modelling KW - Biomechanics KW - Musculoskeletal modelling KW - Occupational exoskeletons Y1 - 2025 U6 - https://doi.org/10.1016/j.apergo.2025.104671 VL - 132 PB - Elsevier ER - TY - JOUR A1 - Uhrhan, Katja A1 - Schwindt, Esther A1 - Witte, Hartmut T1 - Fabrication and Dielectric Validation of an Arm Phantom for Electromyostimulation JF - Bioengineering N2 - Electromyostimulation (EMS) is an up-and-coming training method that demands further fundamental research regarding its safety and efficacy. To investigate the influence of different stimulation parameters, electrode positions and electrode sizes on the resulting voltage in the tissue, a tissue mimicking phantom is needed. Therefore, this study describes the fabrication of a hydrogel arm phantom for EMS applications with the tissue layers of skin, fat, blood and muscle. The phantom was dielectrically validated in the frequency range of 20 Hz to 100 Hz. We also conducted electromyography (EMG) recordings during EMS on the phantom and compared them with the same measurements on a human arm. The phantom reproduces the dielectric properties of the tissues with deviations ranging from 0.8% to more than 100%. Although we found it difficult to find a compromise between mimicking the permittivity and electrical conductivity at the same time, the EMS-EMG measurements showed similar waveforms (1.9-9.5% deviation) in the phantom and human. Our research contributes to the field of dielectric tissue phantoms, as it proposes a multilayer arm phantom for EMS applications. Consequently, the phantom can be used for initial EMS investigations, but future research should focus on further improving the dielectric properties. KW - tissue phantom KW - electromyostimulation KW - electrical muscle stimulation KW - dielectric validation KW - electromyography Y1 - 2024 U6 - https://doi.org/10.3390/bioengineering11070724 SN - 2306-5354 VL - 11 IS - 7 PB - MDPI CY - Basel ER - TY - JOUR A1 - Visscher, Rosa A1 - Wyss, C. A1 - Singh, Navrag B. A1 - Taylor, William R. A1 - Dendorfer, Sebastian A1 - Rutz, E. A1 - Brunner, Reinald T1 - Influence of TAL-TATS surgery on energy production of Tricepts Surae - A musculoskeletal modeling evaluation JF - Gait & Posture Y1 - 2020 U6 - https://doi.org/10.1016/j.gaitpost.2020.08.090 VL - 81 IS - Suppl. 1 SP - 381 EP - 382 PB - Elsevier ER - TY - JOUR A1 - Völlner, Florian A1 - Weber, Tim A. A1 - Weber, Markus A1 - Renkawitz, Tobias A1 - Dendorfer, Sebastian A1 - Grifka, Joachim A1 - Craiovan, Benjamin T1 - A simple method for determining ligament stiffness during total knee arthroplasty in vivo JF - Scientific Reports N2 - 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. KW - Biomechanische Analyse KW - Kniegelenkband KW - Steifigkeit Y1 - 2019 U6 - https://doi.org/10.1038/s41598-019-41732-x VL - 9 SP - 1 EP - 8 PB - Nature ER - TY - CHAP A1 - Weber, Joachim A1 - Doenitz, Christian A1 - Brawanski, Alexander A1 - Palm, Christoph T1 - Data-Parallel MRI Brain Segmentation in Clinicial Use BT - Porting FSL-Fastv4 to GPGPUs T2 - Bildverarbeitung für die Medizin 2015; Algorithmen - Systeme - Anwendungen; Proceedings des Workshops vom 15. bis 17. März 2015 in Lübeck N2 - Structural MRI brain analysis and segmentation is a crucial part in the daily routine in neurosurgery for intervention planning. Exemplarily, the free software FSL-FAST (FMRIB’s Segmentation Library – FMRIB’s Automated Segmentation Tool) in version 4 is used for segmentation of brain tissue types. To speed up the segmentation procedure by parallel execution, we transferred FSL-FAST to a General Purpose Graphics Processing Unit (GPGPU) using Open Computing Language (OpenCL) [1]. The necessary steps for parallelization resulted in substantially different and less useful results. Therefore, the underlying methods were revised and adapted yielding computational overhead. Nevertheless, we achieved a speed-up factor of 3.59 from CPU to GPGPU execution, as well providing similar useful or even better results. KW - Brain Segmentation KW - Magnetic Resonance Imaging KW - Parallel Execution KW - Voxel Spacing KW - General Purpose Graphic Processing Unit KW - Kernspintomografie KW - Gehirn KW - Bildsegmentierung KW - Parallelverarbeitung Y1 - 2015 U6 - https://doi.org/10.1007/978-3-662-46224-9_67 SP - 389 EP - 394 PB - Springer CY - Berlin ER - TY - JOUR A1 - Weber, Karsten T1 - Promoting Individual Well-Being, Increasing Social Welfare, and Securing Genetic Diversity Simultaneously BT - It Is a Matter of Degree JF - American Journal of Bioethics Y1 - 2015 U6 - https://doi.org/10.1080/15265161.2015.1028660 VL - 15 IS - 6 SP - 36 EP - 37 ER - TY - JOUR A1 - Weber, Karsten T1 - Is there really a concept called "inherent ethical concern"? JF - American Journal of Bioethics Neuroscience Y1 - 2014 U6 - https://doi.org/10.1080/21507740.2013.868377 VL - 5 IS - 1 SP - 39 EP - 40 ER - TY - CHAP A1 - Weber, Karsten ED - Siegetsleitner, Anne ED - Oberprantacher, Andreas ED - Frick, Marie-Luisa ED - Metschl, Ulrich T1 - Civil Society as a Means against Hate Speech BT - A Baseless Hope T2 - Crisis and critique: philosophical analysis and current events N2 - On closer examination, the concept of civil society becomes blurred, for instance, on the crucial question of who belongs to civil society. The different answers to this question show how controversial the concept of civil society is, since it cannot be assumed that members of civil society would be morally particularly preferable actors. If, however, the conceptual foundations of and the question of membership in civil society already raise doubts about this concept, the recourse to civil society as a means against fake news and hate speech itself, which is often heard in public debates, becomes doubtful. KW - Hassrede KW - Bekämpfung KW - Zivilgesellschaft Y1 - 2021 SN - 9783110702255 U6 - https://doi.org/10.1515/9783110702255-012 SP - 175 EP - 188 PB - De Gruyter CY - Berlin ER - TY - CHAP A1 - Weber, Karsten T1 - Cybersecurity and Ethics BT - An uncommon yet indispensable combination of issues T2 - The Routledge Handbook of Smart Technologies N2 - The text aims to demonstrate that establishing cybersecurity is not only a technical challenge, but that legal, economic, or organizational aspects also play at least as important a role. The provision of cybersecurity raises ethical questions, since cybersecurity can affect moral values such as autonomy, freedom, or privacy. If measurements necessary for the provision of cybersecurity shall be accepted, it is essential to find a balance between the different claims of all stakeholders involved. This aim is achieved through a detailed ethical analysis accompanied by an extensive literature study. As the most important result of this analysis, it becomes obvious that cybersecurity is in competition or even conflict with other values and interests, and that establishing cybersecurity always involves a trade-off. Not only can there be no 100 percent cybersecurity for technical reasons, but if other values and interests are to be considered, this inevitably leads to compromises in cybersecurity. Y1 - 2022 SN - 9780429351921 U6 - https://doi.org/10.4324/9780429351921-36 SP - 608 EP - 622 PB - Routledge CY - New York ER - TY - JOUR A1 - Weber, Karsten A1 - Bittner, Uta A1 - Manzeschke, Arne A1 - Rother, Elisabeth A1 - Quack, Fredericke A1 - Dengler, Kathrin A1 - Fangerau, Heiner T1 - Taking Patient Privacy and Autonomy More Seriously BT - Why an Orwellian Account Is Not Sufficient JF - American Journal of Bioethics Y1 - 2012 U6 - https://doi.org/10.1080/15265161.2012.699147 VL - 12 IS - 9 SP - 51 EP - 53 ER - TY - JOUR A1 - Weber, Karsten A1 - Krug, Henriette A1 - Haug, Sonja A1 - Kühn, Andrea A. A1 - Scharf, Anna T1 - External Observations and Subjective Experiences: Metaphors Used by DBS Patients JF - AJOB Neuroscience Y1 - 2023 U6 - https://doi.org/10.1080/21507740.2023.2246219 VL - 14 IS - 3 SP - 323 EP - 325 PB - Taylor&Francis ER - TY - JOUR A1 - Weber, Karsten A1 - Loi, Michele A1 - Christen, Markus A1 - Kleine, Nadine T1 - Digital Medicine, Cybersecurity, and Ethics BT - An Uneasy Relationship JF - American Journal of Bioethics Y1 - 2018 U6 - https://doi.org/10.1080/15265161.2018.1498935 VL - 18 IS - 9 SP - 52 EP - 53 PB - Taylor&Francis ER - TY - JOUR A1 - Weber, Karsten A1 - Pallas, Frank A1 - Ulbricht, Max-R. T1 - Challenges of Citizen Science: Commons, Incentives, Organizations, and Regulations JF - American Journal of Bioethics Y1 - 2019 U6 - https://doi.org/10.1080/15265161.2019.1619862 VL - 19 IS - 8 SP - 52 EP - 54 ER - TY - JOUR A1 - Weber, Markus A1 - Merle, Christian A1 - Nawabi, Danyal H. A1 - Dendorfer, Sebastian A1 - Grifka, Joachim A1 - Renkawitz, Tobias T1 - Inaccurate offset restoration in total hip arthroplasty results in reduced range of motion JF - Scientific Reports N2 - 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. KW - Adaptive clinical trial KW - Bone imaging Y1 - 2020 U6 - https://doi.org/10.1038/s41598-020-70059-1 VL - 10 IS - 13208 SP - 9 PB - Nature ER - TY - JOUR A1 - Weber, Markus A1 - Suess, Franz A1 - Jerabek, Seth A1 - Meyer, Matthias A1 - Grifka, Joachim A1 - Renkawitz, Tobias A1 - Dendorfer, Sebastian T1 - Kinematic pelvic tilt during gait alters functional cup position in total hip arthroplasty JF - Journal of Orthopaedic Research N2 - Static pelvic tilt impacts functional cup position in total hip arthroplasty (THA). In the current study we investigated the effect of kinematic pelvic changes on cup position. In the course of a prospective controlled trial postoperative 3D-computed tomography (CT) and gait analysis before and 6 and 12 months after THA were obtained in 60 patients. Kinematic pelvic motion during gait was measured using Anybody Modeling System. By fusion with 3D-CT, the impact of kinematic pelvic tilt alterations on cup anteversion and inclination was calculated. Furthermore, risk factors correlating with high pelvic mobility were evaluated. During gait a high pelvic range of motion up to 15.6° exceeding 5° in 61.7% (37/60) of patients before THA was found. After surgery, the pelvis tilted posteriorly by a mean of 4.0 ± 6.6° (p < .001). The pelvic anteflexion led to a mean decrease of −1.9 ± 2.2° (p < .001) for cup inclination and −15.1 ± 6.1° (p < .001) for anteversion in relation to the anterior pelvic plane (APP). Kinematic pelvic changes resulted in a further change up to 2.3° for inclination and up to 12.3° for anteversion. In relation to the preoperative situation differences in postoperative cup position ranged from −4.4 to 4.6° for inclination and from −7.8 to 17.9° for anteversion, respectively. Female sex (p < .001) and normal body weight (p < .001) correlated with high alterations in pelvic tilt. Kinematic pelvic changes highly impact cup anteversion in THA. Surgeons using the APP as reference should aim for a higher anteversion of about 15° due to the functional anteflexion of the pelvis during gait. KW - component position KW - gait analysis KW - kinematics KW - pelvic tilt KW - total hip arthroplasty KW - Hüftgelenkprothese KW - Haltungsfehler KW - Hüftgelenkpfanne Y1 - 2021 U6 - https://doi.org/10.1002/jor.25106 SN - 1554-527X VL - 40 IS - 4 SP - 846 EP - 853 PB - Wiley ER - TY - CHAP A1 - Weber Nunes, Danilo A1 - Rauber, David A1 - Palm, Christoph ED - Palm, Christoph ED - Breininger, Katharina ED - Deserno, Thomas M. ED - Handels, Heinz ED - Maier, Andreas ED - Maier-Hein, Klaus H. ED - Tolxdorff, Thomas T1 - Self-supervised 3D Vision Transformer Pre-training for Robust Brain Tumor Classification T2 - Bildverarbeitung für die Medizin 2025: Proceedings, German Conference on Medical Image Computing, Regensburg March 09-11, 2025 N2 - Brain tumors pose significant challenges in neurology, making precise classification crucial for prognosis and treatment planning. This work investigates the effectiveness of a self-supervised learning approach–masked autoencoding (MAE)–to pre-train a vision transformer (ViT) model for brain tumor classification. Our method uses non-domain specific data, leveraging the ADNI and OASIS-3 MRI datasets, which primarily focus on degenerative diseases, for pretraining. The model is subsequently fine-tuned and evaluated on the BraTS glioma and meningioma datasets, representing a novel use of these datasets for tumor classification. The pre-trained MAE ViT model achieves an average F1 score of 0.91 in a 5-fold cross-validation setting, outperforming the nnU-Net encoder trained from scratch, particularly under limited data conditions. These findings highlight the potential of self-supervised MAE in enhancing brain tumor classification accuracy, even with restricted labeled data. Y1 - 2025 U6 - https://doi.org/10.1007/978-3-658-47422-5_69 SP - 298 EP - 303 PB - Springer Vieweg CY - Wiesbaden ER - TY - JOUR A1 - Weber, Tim A. A1 - Dendorfer, Sebastian A1 - Bulstra, Sjoerd K. A1 - Grifka, Joachim A1 - Verkerke, Gijsbertus Jacob A1 - Renkawitz, Tobias T1 - Gait six month and one-year after computer assisted Femur First THR vs. conventional THR. Results of a patient- and observer- blinded randomized controlled trial JF - Gait & Posture N2 - A prospective randomized controlled trial is presented that is used to compare gait performance between the computer assisted Femur First (CAS FF) operation method and conventional THR (CON). 60 patients underwent a 3D gait analysis of the lower extremity at pre-operative, 6 months post-operative and twelve months post-operative. Detailed verification experiments were facilitated to ensure the quality of data as well as to avoid over-interpreting of the data. The results confirm a similar data-quality as reported in the literature. Walking speed, range of motion and symmetry thereof improved over the follow-up period, without significant differences between the groups. While all parameters do significantly increase over the follow-up period for both groups, there were no significant differences between them at any given time-point. Patients undergoing CAS FF showed a trend to improved hip flexion angle indicating a possible long-term benefit. KW - Biomechanics KW - Combined anteversion KW - Computer-assisted surgery KW - Femur first KW - Gait analysis Y1 - 2016 U6 - https://doi.org/10.1016/j.gaitpost.2016.06.035 VL - vol. 49 SP - 418 EP - 425 ER - TY - JOUR A1 - Weber, Tim A. A1 - Dendorfer, Sebastian A1 - Grifka, Joachim A1 - Verkerke, Gijsbertus Jacob A1 - Renkawitz, Tobias ED - Takagi, Michiaki T1 - Does Computer-Assisted Femur First THR Improve Musculoskeletal Loading Conditions? JF - BioMed Research International N2 - 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. KW - Hüftgelenkprothese KW - Operationstechnik KW - Computerunterstütztes Verfahren KW - Bewegungsapparat KW - Mechanische Belastung Y1 - 2015 U6 - https://doi.org/10.1155/2015/625317 VL - 2015 SP - ID 625317 ER - TY - JOUR A1 - Weber, Tim A1 - Al-Munajjed, Amir Andreas A1 - Verkerke, Gijsbertus Jacob A1 - Dendorfer, Sebastian A1 - Renkawitz, Tobias T1 - Influence of minimally invasive total hip replacement on hip reaction forces and their orientations JF - Journal of Orthopaedic Research N2 - Minimally invasive surgery (MIS) is becoming increasingly popular. Supporters claim that the main advantages of MIS total hip replacement (THR) are less pain and a faster rehabilitation and recovery. Critics claim that safety and efficacy of MIS are yet to be determined. We focused on a biomechanical comparison between surgical standard and MIS approaches for THR during the early recovery of patients. A validated, parameterized musculoskeletal model was set to perform a squat of a 50th percentile healthy European male. A bilateral motion was chosen to investigate effects on the contralateral side. Surgical approaches were simulated by excluding the incised muscles from the computations. Resulting hip reaction forces and their symmetry and orientation were analyzed. MIS THR seemed less influential on the symmetry index of hip reaction forces between the operated and nonoperated leg when compared to the standard lateral approach. Hip reaction forces at peak loads of the standard transgluteal approach were 24% higher on the contralateral side when compared to MIS approaches. Our results suggest that MIS THR contributes to a greater symmetry of hip reaction forces in absolute value as well as force-orientation following THR. KW - THA KW - THR KW - Biomechanics KW - Conventional surgery KW - Early recovery KW - Hüftgelenkprothese KW - Minimal-invasive Chirurgie KW - Biomechanik Y1 - 2014 U6 - https://doi.org/10.1002/jor.22710 VL - 32 IS - 12 SP - 1680 EP - 1687 ER - TY - JOUR A1 - Weber, Tim A1 - Dullien, Silvia A1 - Grifka, Joachim A1 - Renkawitz, Tobias A1 - Dendorfer, Sebastian T1 - Validation of a Motion Capture Laboratory and a new marker-placement protcol for clinical applications JF - Gait & Posture Y1 - 2013 U6 - https://doi.org/10.1016/j.gaitpost.2013.07.229 VL - 38 IS - Suppl. 1 SP - 113 EP - 114 ER - TY - JOUR A1 - Weiherer, Maximilian A1 - Eigenberger, Andreas A1 - Egger, Bernhard A1 - Brébant, Vanessa A1 - Prantl, Lukas A1 - Palm, Christoph T1 - Learning the shape of female breasts: an open-access 3D statistical shape model of the female breast built from 110 breast scans JF - The Visual Computer N2 - We present the Regensburg Breast Shape Model (RBSM)—a 3D statistical shape model of the female breast built from 110 breast scans acquired in a standing position, and the first publicly available. Together with the model, a fully automated, pairwise surface registration pipeline used to establish dense correspondence among 3D breast scans is introduced. Our method is computationally efficient and requires only four landmarks to guide the registration process. A major challenge when modeling female breasts from surface-only 3D breast scans is the non-separability of breast and thorax. In order to weaken the strong coupling between breast and surrounding areas, we propose to minimize the variance outside the breast region as much as possible. To achieve this goal, a novel concept called breast probability masks (BPMs) is introduced. A BPM assigns probabilities to each point of a 3D breast scan, telling how likely it is that a particular point belongs to the breast area. During registration, we use BPMs to align the template to the target as accurately as possible inside the breast region and only roughly outside. This simple yet effective strategy significantly reduces the unwanted variance outside the breast region, leading to better statistical shape models in which breast shapes are quite well decoupled from the thorax. The RBSM is thus able to produce a variety of different breast shapes as independently as possible from the shape of the thorax. Our systematic experimental evaluation reveals a generalization ability of 0.17 mm and a specificity of 2.8 mm. To underline the expressiveness of the proposed model, we finally demonstrate in two showcase applications how the RBSM can be used for surgical outcome simulation and the prediction of a missing breast from the remaining one. Our model is available at https://www.rbsm.re-mic.de/. KW - Statistical shape model KW - Non-rigid surface registration KW - Breast imaging KW - Surgical outcome simulation KW - Breast reconstruction surgery Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-30506 N1 - Corresponding author: Christoph Palm N1 - Zugehörige arXiv-Publikation: https://opus4.kobv.de/opus4-oth-regensburg/frontdoor/index/index/docId/2023 VL - 39 IS - 4 SP - 1597 EP - 1616 PB - Springer Nature ER - TY - CHAP A1 - Weiherer, Maximilian A1 - von Riedheim, Antonia A1 - Brébant, Vanessa A1 - Egger, Bernhard A1 - Palm, Christoph ED - Palm, Christoph ED - Breininger, Katharina ED - Deserno, Thomas M. ED - Handels, Heinz ED - Maier, Andreas ED - Maier-Hein, Klaus H. ED - Tolxdorff, Thomas T1 - iRBSM: A Deep Implicit 3D Breast Shape Model T2 - Bildverarbeitung für die Medizin 2025: Proceedings, German Conference on Medical Image Computing, Regensburg March 09-11, 2025 N2 - We present the first deep implicit 3D shape model of the female breast, building upon and improving the recently proposed Regensburg Breast Shape Model (RBSM). Compared to its PCA-based predecessor, our model employs implicit neural representations; hence, it can be trained on raw 3D breast scans and eliminates the need for computationally demanding non-rigid registration, a task that is particularly difficult for feature-less breast shapes. The resulting model, dubbed iRBSM, captures detailed surface geometry including fine structures such as nipples and belly buttons, is highly expressive, and outperforms the RBSM on different surface reconstruction tasks. Finally, leveraging the iRBSM, we present a prototype application to 3D reconstruct breast shapes from just a single image. Model and code publicly available at https://rbsm.re-mic.de/implicit. Y1 - 2025 U6 - https://doi.org/10.1007/978-3-658-47422-5_11 SP - 38 EP - 43 PB - Springer Vieweg CY - Wiesbaden ER - TY - CHAP A1 - Weiherer, Maximilian A1 - Zorn, Martin A1 - Wittenberg, Thomas A1 - Palm, Christoph ED - Tolxdorff, Thomas ED - Deserno, Thomas M. ED - Handels, Heinz ED - Maier, Andreas ED - Maier-Hein, Klaus H. ED - Palm, Christoph T1 - Retrospective Color Shading Correction for Endoscopic Images T2 - Bildverarbeitung für die Medizin 2020. Algorithmen - Systeme - Anwendungen. Proceedings des Workshops vom 15. bis 17. März 2020 in Berlin N2 - In this paper, we address the problem of retrospective color shading correction. An extension of the established gray-level shading correction algorithm based on signal envelope (SE) estimation to color images is developed using principal color components. Compared to the probably most general shading correction algorithm based on entropy minimization, SE estimation does not need any computationally expensive optimization and thus can be implemented more effciently. We tested our new shading correction scheme on artificial as well as real endoscopic images and observed promising results. Additionally, an indepth analysis of the stop criterion used in the SE estimation algorithm is provided leading to the conclusion that a fixed, user-defined threshold is generally not feasible. Thus, we present new ideas how to develop a non-parametric version of the SE estimation algorithm using entropy. KW - Endoskopie KW - Bildgebendes Verfahren KW - Farbenraum KW - Graustufe Y1 - 2020 SN - 978-3-658-29266-9 U6 - https://doi.org/10.1007/978-3-658-29267-6 SP - 14 EP - 19 PB - Springer Vieweg CY - Wiesbaden ER - TY - JOUR A1 - Weilhammer, Theresa A1 - Warren, Hunter S. A1 - Bliznyuk, Valery A1 - Kutsevol, Nataliya A1 - Booth, Brian W. T1 - Analysis of Photodynamic Therapeutic Treatment of HER2-Positive Breast Cancer In Vitro JF - BioNanoScience N2 - Photodynamic therapy (PDT) is a minimally invasive cancer treatment method. The antitumor effect of PDT mediated by the photosensitizer meta-tetra(hydroxyphenyl)chlorin (m-THPC) was studied in vitro on HER2-positive (HER2+) breast cancer cells. Since the application of m-THPC is limited due to poor tumor targeting abilities, the polymer carrier dextran-grafted-polyacrylamide (D-g-PAA) with attached gold nanoparticles was loaded with m-THPC to provide a light-responsive, tumor targeting nanocomposite. The nanocomposite was absorbed by the cancer cells within 90 min and activated through irradiation with red light at a wavelength of 660 nm. In this study, the efficiency and ideal dose of the nanocomposite were evaluated and determined based on cell viability and induction of apoptosis of HER2+ breast cancer cells and human breast epithelial cells. We demonstrate that the nanocomposite exhibited phototoxicity with cell mortality exceeding 50% for the HER2+ breast cancer cells. In contrast, the human breast epithelial cells were minimally affected at the same concentration of the nanocomposite, demonstrating the tumor-targeting abilities of the developed nanocomposite. Dark toxicity was also comparably lower, indicating the limited effect of the unactivated nanocomposite. The results revealed that apoptosis was the primary mode of cell death in HER2+ breast cancer cells. Apoptotic cell death was induced in HER2+ breast cancer cells via the caspase-3, caspase-9, and Bax pathways. In conclusion, the studied nanocomposite demonstrated excellent PDT performance with good antitumor activity under light irradiation in vitro and is worthy of further investigation as an alternative treatment for HER2+ breast cancer. Y1 - 2025 U6 - https://doi.org/10.1007/s12668-025-01940-4 VL - 15 PB - Springer ER - TY - CHAP A1 - Weiß, Roman A1 - Großmann, Benjamin A1 - Leibold, Marion A1 - Schlegl, Thomas A1 - Wollherr, Dirk A1 - Weiss, Roman A1 - Grossmann, Benjamin T1 - Modeling and nonlinear control of antagonistically actuating pneumatic artificial muscles T2 - 2017 IEEE International Conference on Advanced Intelligent Mechatronics (AIM), 3-7 July 2017, Munich, Germany N2 - This paper discusses modeling and nonlinear control of a joint antagonistically actuated by two pneumatic, artificial muscles. A single model of the whole system is obtained by a combined physical and phenomenological modeling approach. The combined model for the joint, the muscles and the proportional valves results in a nonlinear, affine-in-control system description. The model is used to derive control laws for an input/output linearization approach to linearize the plant. Modeling and parametrization errors are covered via an outer control loop consisting of a state-feedback which is extended by an additional feedback of error integral. Extensive experimental results show the quality of the model and the performance of the respective control laws. KW - FORCE KW - Muscles KW - Pulleys KW - Robot sensing systems KW - Transfer functions KW - Valves Y1 - 2017 U6 - https://doi.org/10.1109/AIM.2017.8014001 SP - 94 EP - 99 PB - IEEE ER -