Medical Technology for Health (MTH) https://heika-research.de/de de Improved Phenotyping of Cardiomypathy Patients by Means of Imaging-Driven Computational Modeling of Cardiac Biomechanics https://heika-research.de/en/research/medical-technology-health-mth/improved-phenotyping-cardiomypathy-patients-means-imaging <span class="field field--name-title field--type-string field--label-hidden">Improved Phenotyping of Cardiomypathy Patients by Means of Imaging-Driven Computational Modeling of Cardiac Biomechanics</span> <span class="field field--name-uid field--type-entity-reference field--label-hidden"><span lang="" about="/index.php/de/user/31" typeof="schema:Person" property="schema:name" datatype="" content="Maria Garcia Hernandez">Maria Garcia H…</span></span> <span class="field field--name-created field--type-created field--label-hidden">Do, 30.08.2018 - 13:29</span> <div class="clearfix text-formatted field field--name-field-summary field--type-text-long field--label-hidden field__item"><p><span><span><span lang="EN-US" xml:lang="EN-US" xml:lang="EN-US">This project is a cooperation between the Institute of Biomedical Engineering (KIT, Karlsruhe) and the University Hospital in Heidelberg. The aim is to combine cardiovascular magnetic resonance imaging (CMR) with computational modeling of cardiac biomechanics in order to improve diagnosis of cardiomyopathy.</span></span></span></p> <p><span><span><span lang="EN-US" xml:lang="EN-US" xml:lang="EN-US">Before a cardiomyopathy case can be examined, a healthy case needs to be represented in-silico correctly. First, we agreed on a measurement protocol, which provides enough data for the computational model for both input and validation. (Note, that for the first examined case, which is a healthy volunteer, an invasive measurement cannot be conducted and therefore no blood pressure data over the whole heart cycle can be collected.) Second, the healthy volunteer  underwent a cardiovascular magnetic resonance imaging procedure: 3D whole heart, 2 chamber view, 4 chamber view, 12 short axis slices Cine and strain encoded MRI (SENC).</span></span></span></p></div> <div class="field field--name-field-research-bridges field--type-entity-reference field--label-above"> <div class="field__label">Forschungsbrücken</div> <div class="field__items"> <div class="field__item"><a href="/index.php/en/research/medical-technology-health-mth" hreflang="en">Medical Technology for Health (MTH)</a></div> </div> </div> <div class="field field--name-field-start-date field--type-datetime field--label-above"> <div class="field__label">Start date</div> <div class="field__item"> <time datetime="2018-01-01T12:00:00Z" class="datetime">01.01.2018</time> </div> </div> <div class="field field--name-field-end-date field--type-datetime field--label-hidden field__item"><time datetime="2018-12-31T12:00:00Z" class="datetime">31.12.2018</time> </div> <div class="field field--name-field-contact-person field--type-entity-reference field--label-above"> <div class="field__label"><h3>Project management</h3></div> <div class="field__items"> <article data-history-node-id="116" role="article" lang="en" about="/index.php/en/prof-dr-med-matthias-friedrich" class="node node--type-people-profile node--view-mode-teaser"> <div class="node__content"> <div class="content-container"> <div class="header-container"> <h2> <a href="/index.php/en/prof-dr-med-matthias-friedrich" rel="bookmark"><span class="field field--name-title field--type-string field--label-hidden">Prof. Dr. med. Matthias Friedrich</span> </a> </h2> </div> <div class="field field--name-field-institute field--type-string field--label-hidden field__item">Cardiovascular Imaging Research</div> <div class="field field--name-field-facility field--type-string field--label-hidden field__item">Heidelberg University Hospital</div> <div class="field field--name-field-link field--type-link field--label-hidden field__item"><a href="https://www.klinikum.uni-heidelberg.de/index.php?id=140715&amp;L=0">Matthias Friedrich</a></div> </div> </div> </article> <article data-history-node-id="117" role="article" lang="en" about="/index.php/en/prof-dr-rer-nat-olaf-dossel" class="node node--type-people-profile node--view-mode-teaser"> <div class="node__content"> <div class="content-container"> <div class="header-container"> <h2> <a href="/index.php/en/prof-dr-rer-nat-olaf-dossel" rel="bookmark"><span class="field field--name-title field--type-string field--label-hidden">Prof. Dr. rer. nat. Olaf Dössel</span> </a> </h2> </div> <div class="field field--name-field-institute field--type-string field--label-hidden field__item">Institute of Biomedical Engineering</div> <div class="field field--name-field-facility field--type-string field--label-hidden field__item">Karlsruhe Institute of Technology</div> </div> </div> </article> </div> </div> Thu, 30 Aug 2018 11:29:57 +0000 Maria Garcia Hernandez 134 at https://heika-research.de Invasions- und Genexpressionsanalysen im Urothelkarzinom der Harnblase: Entwicklung eines mikrofluidischen in vitro Lymphgefäßmodells https://heika-research.de/en/research/medical-technology-health-mth/invasions-und-genexpressionsanalysen-im-urothelkarzinom-der <span class="field field--name-title field--type-string field--label-hidden">Invasions- und Genexpressionsanalysen im Urothelkarzinom der Harnblase: Entwicklung eines mikrofluidischen in vitro Lymphgefäßmodells</span> <span class="field field--name-uid field--type-entity-reference field--label-hidden"><span lang="" about="/index.php/de/user/31" typeof="schema:Person" property="schema:name" datatype="" content="Maria Garcia Hernandez">Maria Garcia H…</span></span> <span class="field field--name-created field--type-created field--label-hidden">Do, 30.08.2018 - 13:42</span> <div class="clearfix text-formatted field field--name-field-summary field--type-text-long field--label-hidden field__item"><p>Das Urothelkarzinom der Blase zählt zu der häufigsten Krebserkrankung weltweit und weist eine hohe Morbidität bzw. Mortalität auf. Ein wichtiger Faktor bei der Progression im Urothelkarzinom der Blase ist die Lymphgefäßinvasion. Die molekularen Mechanismen, die bei der Progression und Invasion des Urothelkarzinoms der Blase eine Rolle spielen, sind nicht vollständig geklärt. Derartige molekulare und zelluläre Untersuchungen sind auf Grund der limitierten in vivo und in vitro Modelle eingeschränkt möglich.</p> <p><span><span><span><span>Im Rahmen dieses Projekts wurde der Prototyp eines mikrofluidischen Gefäßsystems als artifizielles Modell des Lymphgefäßes bzw. Lymphknotens unter Berücksichtigung der rheologischen und physikalischen Eigenschaften entwickelt. Dazu wurden verschiedene Membranen als Gewebeschranke getestet und die Kultivierung von Lymphendothelzellen gelang auf PET-Membranen und PET-Gewebe. Die Zellen können über spezifische Ventilsysteme isoliert werden und stehen für weitere sensitive Genexpressionsanalysen wie der qRT-PCR zur Verfügung.</span></span></span></span></p> <p><span><span><span>Für eine bessere physiologische Nachbildung der Lymph-Gewebe-Schranke wurde statt einer Membran ein Kollagen 1 Hydrogel verwendet, auf dem die Kultivierung von Lymphendothelzellen, primären Blasenfibroblasten und Blasenkarzinomzelllinien möglich ist.</span></span></span><br />  </p></div> <div class="field field--name-field-research-bridges field--type-entity-reference field--label-above"> <div class="field__label">Forschungsbrücken</div> <div class="field__items"> <div class="field__item"><a href="/index.php/en/research/medical-technology-health-mth" hreflang="en">Medical Technology for Health (MTH)</a></div> </div> </div> <div class="field field--name-field-start-date field--type-datetime field--label-above"> <div class="field__label">Start date</div> <div class="field__item"> <time datetime="2018-01-01T12:00:00Z" class="datetime">01.01.2018</time> </div> </div> <div class="field field--name-field-end-date field--type-datetime field--label-hidden field__item"><time datetime="2018-12-31T12:00:00Z" class="datetime">31.12.2018</time> </div> <div class="field field--name-field-contact-person field--type-entity-reference field--label-above"> <div class="field__label"><h3>Project management</h3></div> <div class="field__items"> <article data-history-node-id="118" role="article" lang="en" about="/index.php/en/pd-dr-med-philipp-erben" class="node node--type-people-profile node--view-mode-teaser"> <div class="node__content"> <div class="content-container"> <div class="header-container"> <h2> <a href="/index.php/en/pd-dr-med-philipp-erben" rel="bookmark"><span class="field field--name-title field--type-string field--label-hidden">PD Dr. med. Philipp Erben</span> </a> </h2> </div> <div class="field field--name-field-institute field--type-string field--label-hidden field__item">Medical Faculty Mannheim</div> <div class="field field--name-field-facility field--type-string field--label-hidden field__item">University of Heidelberg</div> <div class="field field--name-field-link field--type-link field--label-hidden field__item"><a href="https://www.umm.uni-heidelberg.de/forschung/forschungsschwerpunkte/onkologie/mitglieder/pd-dr-philipp-erben/">Philipp Erben</a></div> </div> </div> </article> <article data-history-node-id="119" role="article" lang="en" about="/index.php/en/prof-dr-andreas-guber" class="node node--type-people-profile node--view-mode-teaser"> <div class="node__content"> <div class="content-container"> <div class="header-container"> <h2> <a href="/index.php/en/prof-dr-andreas-guber" rel="bookmark"><span class="field field--name-title field--type-string field--label-hidden">Prof. Dr. Andreas Guber</span> </a> </h2> </div> <div class="field field--name-field-institute field--type-string field--label-hidden field__item">Institute of Microstructure Technology</div> <div class="field field--name-field-facility field--type-string field--label-hidden field__item">Karlsruhe Institute of Technology</div> <div class="field field--name-field-link field--type-link field--label-hidden field__item"><a href="https://www.imt.kit.edu/1443_1488.php">Andreas Guber</a></div> </div> </div> </article> </div> </div> Thu, 30 Aug 2018 11:42:51 +0000 Maria Garcia Hernandez 135 at https://heika-research.de 3D gedruckte Nano-Zellgerüstträger für die in situ Knorpelregeneration zur Behandlung von Gelenkknorpelschäden. Untersuchungen zum Zellrecruitment in einem Bioreaktor. https://heika-research.de/en/research/medical-technology-health-mth/3d-gedruckte-nano-zellgerusttrager-fur-die-situ <span class="field field--name-title field--type-string field--label-hidden">3D gedruckte Nano-Zellgerüstträger für die in situ Knorpelregeneration zur Behandlung von Gelenkknorpelschäden. Untersuchungen zum Zellrecruitment in einem Bioreaktor.</span> <span class="field field--name-uid field--type-entity-reference field--label-hidden"><span lang="" about="/index.php/de/user/32" typeof="schema:Person" property="schema:name" datatype="">Regine Kleber</span></span> <span class="field field--name-created field--type-created field--label-hidden">Mo, 12.11.2018 - 17:10</span> <div class="clearfix text-formatted field field--name-field-summary field--type-text-long field--label-hidden field__item"><p><span><span><span><span><span>Im Rahmen des Projektes sollen künstliche Zellgerüstträger zur in situ Regeneration von hyalinem Knorpel zur Behandlung von Knorpelschäden mittels Nano 3D-Druck hergestellt werden. Durch den Einsatz der sog. „Zwei Photonen Lithographie“ (Nanoscribe) wird es möglich, im Nanometermaßstab genaue Zellgerüste additiv herzustellen. Durch solch einen additiven und hochpräzisen Aufbau der Zellgerüste sind komplexe Strukturen realisierbar, mit denen die anspruchsvollen mechanischen Eigenschaften von natürlichem hyalinem Knorpel realisiert werden können. Diese 3D Scaffolds sollen dabei als Gerüst für Stammzellen und anderen Zellen dienen und diesen ermöglichen, neue extrazelluläre Matrix zu produzieren und im Idealfall wieder gesundes hyalines Knorpelgewebe auszubilden.</span></span></span></span></span></p> <p><span><span><span><span><span>Zuerst werden Vorversuche mit starren Scaffolds durchgeführt. Hierbei sollen zunächst optimale Parameter, wie z.B. Porengröße, Oberflächenqualität usw. sowie deren Einfluss auf die Besiedelung der Scaffolds durch verschiedene Zelltypen (z.B. Chondrosarcomzelllinie, Stammzellen) identifiziert werden.</span></span></span></span></span></p> <p><span><span><span><span><span>Auf diesen Ergebnissen und auf KIT-Seite durchgeführten mechanischen Simulationen basierend werden elastisch verformbare Zellgerüstträger konstruiert und mittels 3D Druck hergestellt, die die mechanischen Eigenschaften des hyalinen Knorpels möglichst gut nachbilden sollen. Diese elastischen Scaffolds werden in einem Bioreaktor kontinuierlich mechanisch belastet und anschließend untersucht, ob unter den verwendeten Parametern ein erfolgreiches Zellrecruitment von Stammzellen aus einem unteren Reservoir des Bioreaktors in das daraufliegende Scaffold stattfindet. Dieser wichtige und entscheidende Vorgang wäre der Ausgangspunkt für eine in situ Regeneration von Knorpelgewebe, der den klinischen Gegebenheiten bei einer sog. Matrix assoziierten Chondrogenese (AMIC®) nahe kommt.</span></span></span></span></span></p> <p> </p></div> <div class="field field--name-field-research-bridges field--type-entity-reference field--label-above"> <div class="field__label">Forschungsbrücken</div> <div class="field__items"> <div class="field__item"><a href="/index.php/en/research/medical-technology-health-mth" hreflang="en">Medical Technology for Health (MTH)</a></div> </div> </div> <div class="field field--name-field-start-date field--type-datetime field--label-above"> <div class="field__label">Start date</div> <div class="field__item"> <time datetime="2019-01-01T12:00:00Z" class="datetime">01.01.2019</time> </div> </div> <div class="field field--name-field-end-date field--type-datetime field--label-hidden field__item"><time datetime="2019-12-31T12:00:00Z" class="datetime">31.12.2019</time> </div> <div class="field field--name-field-contact-person field--type-entity-reference field--label-above"> <div class="field__label"><h3>Project management</h3></div> <div class="field__items"> <article data-history-node-id="197" role="article" lang="en" about="/index.php/en/prof-dr-markus-schwarz" class="node node--type-people-profile node--view-mode-teaser"> <div class="node__content"> <div class="content-container"> <div class="header-container"> <h2> <a href="/index.php/en/prof-dr-markus-schwarz" rel="bookmark"><span class="field field--name-title field--type-string field--label-hidden">Prof. Dr. Markus Schwarz</span> </a> </h2> </div> <div class="field field--name-field-institute field--type-string field--label-hidden field__item">Medical Faculty Mannheim / Experimental Orthopedics and Trauma Surgery </div> <div class="field field--name-field-facility field--type-string field--label-hidden field__item">Heidelberg University</div> <div class="field field--name-field-link field--type-link field--label-hidden field__item"><a href="https://w2.umm.de/ouz-orthopaedie-mannheim/forschung-lehre/experimentelle-orthopaedie-und-unfallchirurgie/">Research Group Schwarz</a></div> </div> </div> </article> <article data-history-node-id="119" role="article" lang="en" about="/index.php/en/prof-dr-andreas-guber" class="node node--type-people-profile node--view-mode-teaser"> <div class="node__content"> <div class="content-container"> <div class="header-container"> <h2> <a href="/index.php/en/prof-dr-andreas-guber" rel="bookmark"><span class="field field--name-title field--type-string field--label-hidden">Prof. Dr. Andreas Guber</span> </a> </h2> </div> <div class="field field--name-field-institute field--type-string field--label-hidden field__item">Institute of Microstructure Technology</div> <div class="field field--name-field-facility field--type-string field--label-hidden field__item">Karlsruhe Institute of Technology</div> <div class="field field--name-field-link field--type-link field--label-hidden field__item"><a href="https://www.imt.kit.edu/1443_1488.php">Andreas Guber</a></div> </div> </div> </article> </div> </div> Mon, 12 Nov 2018 16:10:56 +0000 Regine Kleber 210 at https://heika-research.de Magnetic resonance-guided opening of the blood-brain barrier using focused ultrasound for cell-mediated therapies of brain diseases https://heika-research.de/en/research/medical-technology-health-mth/magnetic-resonance-guided-opening-blood-brain-barrier-using <span class="field field--name-title field--type-string field--label-hidden">Magnetic resonance-guided opening of the blood-brain barrier using focused ultrasound for cell-mediated therapies of brain diseases</span> <span class="field field--name-uid field--type-entity-reference field--label-hidden"><span lang="" about="/index.php/de/user/31" typeof="schema:Person" property="schema:name" datatype="" content="Maria Garcia Hernandez">Maria Garcia H…</span></span> <span class="field field--name-created field--type-created field--label-hidden">Di, 10.12.2019 - 15:40</span> <div class="clearfix text-formatted field field--name-field-summary field--type-text-long field--label-hidden field__item"><p><span lang="EN-GB" xml:lang="EN-GB" xml:lang="EN-GB"><span><span>Cerebral amyloid angiopathy (CAA) is a neurodegenerative disorder and results in vascular dysfunction, microinfarcts and brain bleedings. Stem cells were found to be a potent regenerative therapy in the related Alzheimer’s disease, but their targeting is difficult since they are hindered by the blood-brain barrier (BBB). Focused ultrasound (FUS) provides a new strategy for stem cell application. It is able to open the BBB in a noninvasive, local and transient way. Its combination with magnetic resonance imaging (MRI) allows for guidance, targeting and monitoring in real time (MRgFUS). Challenges result from the acoustic pressure weakening deriving from the skull or targeting of the ultrasound focus. Additionally, settings and application protocols in pre-clinical studies with animal models differ significantly. Therefore, ultrasound parameters like frequency, burst duration, burst repetition frequency, total exposure time and acoustic pressure amplitude have to be fine-tuned for safe BBB opening. Furthermore, there is a tremendous lack of knowledge regarding to the formation of brain bleedings post FUS. The proposed HEiKA project aims at developing and evaluating a non-invasive and reliable BBB opening in mice to enable systemic administration of stem cells to brain parenchyma. In order to establish a reliable BBB opening protocol, we first focus on an adequate therapy planning using automated segmentation of mouse anatomy and estimation of the FUS parameters with acoustic or elastic simulations. Second, we will do animal experiments in a transgenic mouse model for CAA in order to estimate appropriate simulation parameters and to evaluate BBB opening protocols in aged animals. The long-term goal of our collaborative project is to examine the neuroprotective and regenerative effect of stem cells on amyloid metabolism and CAA. Findings of this proof of principle project will then be usable for further cell-based therapies in central nervous system (CNS) disorders.</span></span></span></p></div> <div class="field field--name-field-research-bridges field--type-entity-reference field--label-above"> <div class="field__label">Forschungsbrücken</div> <div class="field__items"> <div class="field__item"><a href="/index.php/en/research/medical-technology-health-mth" hreflang="en">Medical Technology for Health (MTH)</a></div> </div> </div> <div class="field field--name-field-start-date field--type-datetime field--label-above"> <div class="field__label">Start date</div> <div class="field__item"> <time datetime="2020-01-01T12:00:00Z" class="datetime">01.01.2020</time> </div> </div> <div class="field field--name-field-end-date field--type-datetime field--label-hidden field__item"><time datetime="2020-12-31T12:00:00Z" class="datetime">31.12.2020</time> </div> <div class="field field--name-field-contact-person field--type-entity-reference field--label-above"> <div class="field__label"><h3>Project management</h3></div> <div class="field__items"> <article data-history-node-id="275" role="article" lang="en" about="/index.php/en/prof-dr-med-marc-fatar" class="node node--type-people-profile node--view-mode-teaser"> <div class="node__content"> <div class="content-container"> <div class="header-container"> <h2> <a href="/index.php/en/prof-dr-med-marc-fatar" rel="bookmark"><span class="field field--name-title field--type-string field--label-hidden">Prof. Dr. med. Marc Fatar</span> </a> </h2> </div> <div class="field field--name-field-institute field--type-string field--label-hidden field__item">Neurologische Klinik</div> <div class="field field--name-field-facility field--type-string field--label-hidden field__item">Medizinische Fakultät Mannheim</div> <div class="field field--name-field-link field--type-link field--label-hidden field__item"><a href="https://www.umm.uni-heidelberg.de/forschung/forschungsschwerpunkte/vaskulaere-biologie-medizin/mitglieder/prof-dr-marc-fatar/">Marc Fatar</a></div> </div> </div> </article> <article data-history-node-id="276" role="article" lang="en" about="/index.php/en/pd-dr-rer-nat-nicole-ruiter" class="node node--type-people-profile node--view-mode-teaser"> <div class="node__content"> <div class="content-container"> <div class="header-container"> <h2> <a href="/index.php/en/pd-dr-rer-nat-nicole-ruiter" rel="bookmark"><span class="field field--name-title field--type-string field--label-hidden">PD Dr. rer. nat. Nicole Ruiter</span> </a> </h2> </div> <div class="field field--name-field-institute field--type-string field--label-hidden field__item">Institut für Prozessdatenverarbeitung und Elektronik</div> <div class="field field--name-field-facility field--type-string field--label-hidden field__item">Karlsruher Institut für Technologie</div> <div class="field field--name-field-link field--type-link field--label-hidden field__item"><a href="https://www.ipe.kit.edu/98.php">Nicole Ruiter</a></div> </div> </div> </article> </div> </div> Tue, 10 Dec 2019 14:40:42 +0000 Maria Garcia Hernandez 287 at https://heika-research.de A radiation free, deep learning based classification of craniofacial deformities on surface scans. Paving the methodical way towards a patient’s digital twin. https://heika-research.de/en/research/medical-technology-health-mth/radiation-free-deep-learning-based-classification <span class="field field--name-title field--type-string field--label-hidden">A radiation free, deep learning based classification of craniofacial deformities on surface scans. Paving the methodical way towards a patient’s digital twin.</span> <span class="field field--name-uid field--type-entity-reference field--label-hidden"><span lang="" about="/index.php/de/user/31" typeof="schema:Person" property="schema:name" datatype="" content="Maria Garcia Hernandez">Maria Garcia H…</span></span> <span class="field field--name-created field--type-created field--label-hidden">Di, 10.12.2019 - 15:42</span> <div class="clearfix text-formatted field field--name-field-summary field--type-text-long field--label-hidden field__item"><p><span lang="EN-GB" xml:lang="EN-GB" xml:lang="EN-GB"><span><span>We hereby apply for a HEiKA project funding for a cooperation between the Karlsruhe Institute of Technology (KIT), Institute for Biomedical Technology (IBT) and the University Hospital of Heidelberg (UNI-HD), Institute for Medical Biometry and Informatics, Research Group Medical Informatics (IMBI) and Department of Oral and Maxillofacial Surgery (CMF) and Department of Orthodontics. The goal of this project is to explore and develop an innovative application for convolutional neural networks (CNN) in clinical medicine. As both universities excel in their field of interest and research, we are looking forward using the existing knowledge to develop the basis to a self-adaptive digital model of a patient, which we refer to as a digital twin. The topic of the initial research project is to lay the groundwork to a deep learning based diagnostic tool, that shall be trained to determine severe growth anomalies such as premature cranial synostosis of the face and skull in infants from mild growth anomalies and classify those conditions. Additionally, to engage a clinically relevant question in a scientifically not predescribed way, we are looking into the training of neural networks (NNs) for other questions of clinical relevance such as diagnostic or predictive clinical models. The gained knowledge and established workflows will lay the basis to a larger scaled research project. As research on artificial intelligence (AI) in medicine is a growing topic, the practical but essential questions of data handling are the basis for further projects. The results are published from a clinical and computational point of view. The findings will then be used to submit a successful Deutsche Forschungsgemeinschaft (DFG) application. The working title of this following DFG project is “The patients digital twin – a deep learning based model for diagnostics and prediction of clinical data” and the application for a consequential third-party funding is a part of the research project.</span></span></span></p></div> <div class="field field--name-field-research-bridges field--type-entity-reference field--label-above"> <div class="field__label">Forschungsbrücken</div> <div class="field__items"> <div class="field__item"><a href="/index.php/en/research/medical-technology-health-mth" hreflang="en">Medical Technology for Health (MTH)</a></div> </div> </div> <div class="field field--name-field-start-date field--type-datetime field--label-above"> <div class="field__label">Start date</div> <div class="field__item"> <time datetime="2020-01-01T12:00:00Z" class="datetime">01.01.2020</time> </div> </div> <div class="field field--name-field-end-date field--type-datetime field--label-hidden field__item"><time datetime="2020-12-31T12:00:00Z" class="datetime">31.12.2020</time> </div> <div class="field field--name-field-contact-person field--type-entity-reference field--label-above"> <div class="field__label"><h3>Project management</h3></div> <div class="field__items"> <article data-history-node-id="277" role="article" lang="en" about="/index.php/en/prof-apl-dr-dr-christian-freudlsperger" class="node node--type-people-profile node--view-mode-teaser"> <div class="node__content"> <div class="content-container"> <div class="header-container"> <h2> <a href="/index.php/en/prof-apl-dr-dr-christian-freudlsperger" rel="bookmark"><span class="field field--name-title field--type-string field--label-hidden">Prof. (apl.) Dr. Dr. Christian Freudlsperger</span> </a> </h2> </div> <div class="field field--name-field-institute field--type-string field--label-hidden field__item">Klinik und Poliklinik für Mund-, Kiefer- und Gesichtschirurgie</div> <div class="field field--name-field-facility field--type-string field--label-hidden field__item">Universitätsklinikum Heidelberg</div> <div class="field field--name-field-link field--type-link field--label-hidden field__item"><a href="https://www.klinikum.uni-heidelberg.de/personen/prof-apl-dr-med-dr-med-dent-christian-freudlsperger-1200">Christian Freudlsperger</a></div> </div> </div> </article> <article data-history-node-id="278" role="article" lang="en" about="/index.php/en/prof-dr-werner-nahm" class="node node--type-people-profile node--view-mode-teaser"> <div class="node__content"> <div class="content-container"> <div class="header-container"> <h2> <a href="/index.php/en/prof-dr-werner-nahm" rel="bookmark"><span class="field field--name-title field--type-string field--label-hidden">Prof. Dr. Werner Nahm</span> </a> </h2> </div> <div class="field field--name-field-function-1 field--type-string field--label-hidden field__item">Director Research Bridge MTH</div> <div class="field field--name-field-institute field--type-string field--label-hidden field__item">Institut für Biomedizinische Technik</div> <div class="field field--name-field-facility field--type-string field--label-hidden field__item">Karlsruher Institut für Technologie</div> <div class="field field--name-field-link field--type-link field--label-hidden field__item"><a href="https://www.ibt.kit.edu/Nahm.php">Werner Nahm</a></div> </div> </div> </article> </div> </div> Tue, 10 Dec 2019 14:42:03 +0000 Maria Garcia Hernandez 288 at https://heika-research.de Particle therapy beam monitoring with HV-CMOS sensors https://heika-research.de/en/research/medical-technology-health-mth/particle-therapy-beam-monitoring-hv-cmos-sensors <span class="field field--name-title field--type-string field--label-hidden">Particle therapy beam monitoring with HV-CMOS sensors</span> <span class="field field--name-uid field--type-entity-reference field--label-hidden"><span lang="" about="/index.php/de/user/31" typeof="schema:Person" property="schema:name" datatype="" content="Maria Garcia Hernandez">Maria Garcia H…</span></span> <span class="field field--name-created field--type-created field--label-hidden">Di, 10.12.2019 - 15:44</span> <div class="clearfix text-formatted field field--name-field-summary field--type-text-long field--label-hidden field__item"><p><span><span><span><span><span lang="EN-GB" xml:lang="EN-GB" xml:lang="EN-GB">Radiotherapy is an important pillar in the therapy of cancers and is prescribed to ~50% of cancer patients. Standard radiotherapy uses photon radiation whereas particle therapy uses high energy protons and carbon ions to destroy tumor cells in the body of patients. To achieve local tumor control a well-controlled particle beam in terms of position and dose is of utmost importance for the success of the therapy and the patient’s health. The beam control system requires precise and fast measurement of the dose and beam position which must be provided by the beam monitors. Currently, these are gas-filled detectors.</span></span></span></span></span></p> <p><span><span><span><span><span lang="EN-GB" xml:lang="EN-GB" xml:lang="EN-GB">Looking at particle detectors in modern particle physics experiments we find solid-state devices, such as high-voltage complementary metal oxide semiconductor (HV-CMOS) sensors, are ubiquitous. They offer much better time and spatial resolution, which could be highly beneficial for use in a beam monitoring system for particle therapy. As ion beam therapy guided by magnetic resonance imaging (MR-guided) is being developed these days, HV-CMOS sensors shall be tested in the presence of magnetic fields. HV-CMOS sensors are thin (&lt;150 μm) monolithic devices, which offer high spatial resolution and detection efficiency for ionizing particles as well as customizable on-chip data processing (like clustering, particle counting, signal charge integration, etc). Within this proposed project we want to explore the feasibility to apply this technology to the precise and fast monitoring of a therapeutic particle beam.</span></span></span></span></span></p> <p><span><span><span><span><span lang="EN-GB" xml:lang="EN-GB" xml:lang="EN-GB">The two partners complement each other in an ideal way: the team from the Heidelberg Ion beam Therapy center (HIT) contributes the know-how on the beam delivery system and patient treatment, while the team from the Institute for Data Processing and Electronics (IPE) at KIT has proven expertise in delivering detector systems for extreme environments. HV-CMOS sensors have been pioneered by one of the PMs (I. Peric) and are being designed and developed at the KIT ASIC and Detector Lab (ADL) associated to the IPE.</span></span></span></span></span></p> <p><span><span><span><span><span lang="EN-GB" xml:lang="EN-GB" xml:lang="EN-GB">Within this project an optimized test sensor will be designed and tested in beam at HIT. After successful evaluation of the pixel design a larger demonstrator sensor will be developed, which also includes the investigation of multi-sensor interconnection techniques to cover the required large area of 25 cm x 25 cm.</span></span></span></span></span></p> <p><span lang="EN-GB" xml:lang="EN-GB" xml:lang="EN-GB"><span><span>During this project we will also derive concepts for proper housing and mounting of the sensor as well as for a DAQ system capable to process and provide the required data for the therapy control system. These sensor developments and conceptual studies of the auxiliary systems will allow us to better quantify the budgetary needs and further development steps towards a prototype system for clinical use.</span></span></span></p></div> <div class="field field--name-field-research-bridges field--type-entity-reference field--label-above"> <div class="field__label">Forschungsbrücken</div> <div class="field__items"> <div class="field__item"><a href="/index.php/en/research/medical-technology-health-mth" hreflang="en">Medical Technology for Health (MTH)</a></div> <div class="field__item"><a href="/index.php/en/research/particle-physics-astroparticle-physics-and-cosmology-pac" hreflang="en">Particle Physics, Astroparticle Physics and Cosmology (PAC)</a></div> </div> </div> <div class="field field--name-field-start-date field--type-datetime field--label-above"> <div class="field__label">Start date</div> <div class="field__item"> <time datetime="2020-01-01T12:00:00Z" class="datetime">01.01.2020</time> </div> </div> <div class="field field--name-field-end-date field--type-datetime field--label-hidden field__item"><time datetime="2020-12-31T12:00:00Z" class="datetime">31.12.2020</time> </div> <div class="field field--name-field-contact-person field--type-entity-reference field--label-above"> <div class="field__label"><h3>Project management</h3></div> <div class="field__items"> <article data-history-node-id="279" role="article" lang="en" about="/en/prof-dr-dr-jurgen-debus" class="node node--type-people-profile node--view-mode-teaser"> <div class="node__content"> <div class="content-container"> <div class="header-container"> <h2> <a href="/en/prof-dr-dr-jurgen-debus" rel="bookmark"><span class="field field--name-title field--type-string field--label-hidden">Prof. Dr. Dr. Jürgen Debus</span> </a> </h2> </div> <div class="field field--name-field-institute field--type-string field--label-hidden field__item">Klinik für Radioonkologie und Strahlentherapie</div> <div class="field field--name-field-facility field--type-string field--label-hidden field__item">Universitätsklinikum Heidelberg</div> <div class="field field--name-field-link field--type-link field--label-hidden field__item"><a href="https://www.klinikum.uni-heidelberg.de/personen/prof-dr-med-rer-nat-juergen-debus-1274">Jürgen Debus</a></div> </div> </div> </article> <article data-history-node-id="294" role="article" lang="en" about="/en/prof-dr-ivan-peric" class="node node--type-people-profile node--view-mode-teaser"> <div class="node__content"> <div class="content-container"> <div class="header-container"> <h2> <a href="/en/prof-dr-ivan-peric" rel="bookmark"><span class="field field--name-title field--type-string field--label-hidden">Prof. Dr. Ivan Peric</span> </a> </h2> </div> <div class="field field--name-field-institute field--type-string field--label-hidden field__item">Institut für Prozessdatenverarbeitung und Elektronik</div> <div class="field field--name-field-facility field--type-string field--label-hidden field__item">Karlsruher Institut für Technologie</div> <div class="field field--name-field-link field--type-link field--label-hidden field__item"><a href="http://adl.ipe.kit.edu/english/21_56.php">Ivan Peric</a></div> </div> </div> </article> </div> </div> Tue, 10 Dec 2019 14:44:16 +0000 Maria Garcia Hernandez 289 at https://heika-research.de 3D bioprinting of heart tissue for transplantation - Effects of materials and endothelial factors on stem cell maturation to functional myocardial tissue https://heika-research.de/en/research/medical-technology-health-mth/3d-bioprinting-heart-tissue-transplantation-effects <span class="field field--name-title field--type-string field--label-hidden">3D bioprinting of heart tissue for transplantation - Effects of materials and endothelial factors on stem cell maturation to functional myocardial tissue</span> <span class="field field--name-uid field--type-entity-reference field--label-hidden"><span lang="" about="/index.php/de/user/31" typeof="schema:Person" property="schema:name" datatype="" content="Maria Garcia Hernandez">Maria Garcia H…</span></span> <span class="field field--name-created field--type-created field--label-hidden">Di, 10.12.2019 - 15:46</span> <div class="clearfix text-formatted field field--name-field-summary field--type-text-long field--label-hidden field__item"><p><span><span><span><span><span lang="EN-GB" xml:lang="EN-GB" xml:lang="EN-GB">Heart disease is the cause of most deaths worldwide. Although some patients can be treated by heart transplantation, thousands of patients suffer due to a lack of donor organs.</span></span></span></span></span></p> <p><span><span><span><span><span lang="EN-GB" xml:lang="EN-GB" xml:lang="EN-GB">Therefore, it is important in the field of regenerative medicine to develop new therapies in order to meet the emergency. In this project, artificial heart tissue will be produced by 3D bioprinting. In a proof of principle study a prototype murine heart tissue will be produced in 3D in order to test its functionality, cell communication and tissue differentiation in vivo and ex vivo. In a second step, the structure will be prepared to be scaled to a size of a human heart.</span></span></span></span></span></p> <p><span lang="EN-GB" xml:lang="EN-GB" xml:lang="EN-GB"><span><span>Different cardiovascular cell types, differentiated from mouse embryonic stem cells (mESCs) will be printed in individually adapted hydrogels with different printing processes and spatial resolutions to produce an artificial heart that comes as close as possible to a murine heart in terms of shape, topography and functionality. Vascularization will be achieved by printing of sacrificial hydrogel structures to form a pre-formed vascular network, which will be subsequently colonized with endothelial cells. During and after the printing process, the artificial blood vessels will be perfused with a newly developed microperfusion system in order to supply the printed organ with oxygen and nutrients ex vivo. The printed organs will be further subjected to structural and functional testing in vitro and in vivo after transplantation in mice. Here, the role of endothelial-derived signals through direct cellular contacts or angiocrine signals on cardiomyocyte proliferation, survival and maturation will be investigated. Within this project, we will closely collaborate with the Tal Dvir’s group that has achieved a major breakthrough in the field of 3D bioprinting.</span></span></span></p></div> <div class="field field--name-field-research-bridges field--type-entity-reference field--label-above"> <div class="field__label">Forschungsbrücken</div> <div class="field__items"> <div class="field__item"><a href="/index.php/en/research/medical-technology-health-mth" hreflang="en">Medical Technology for Health (MTH)</a></div> <div class="field__item"><a href="/index.php/en/research/synthetic-biology-sb" hreflang="en">Synthetic Biology (SB)</a></div> </div> </div> <div class="field field--name-field-start-date field--type-datetime field--label-above"> <div class="field__label">Start date</div> <div class="field__item"> <time datetime="2020-01-01T12:00:00Z" class="datetime">01.01.2020</time> </div> </div> <div class="field field--name-field-end-date field--type-datetime field--label-hidden field__item"><time datetime="2020-12-31T12:00:00Z" class="datetime">31.12.2020</time> </div> <div class="field field--name-field-contact-person field--type-entity-reference field--label-above"> <div class="field__label"><h3>Project management</h3></div> <div class="field__items"> <article data-history-node-id="280" role="article" lang="en" about="/index.php/en/prof-dr-gergana-dobreva" class="node node--type-people-profile node--view-mode-teaser"> <div class="node__content"> <div class="content-container"> <div class="header-container"> <h2> <a href="/index.php/en/prof-dr-gergana-dobreva" rel="bookmark"><span class="field field--name-title field--type-string field--label-hidden">Prof. Dr. Gergana Dobreva</span> </a> </h2> </div> <div class="field field--name-field-institute field--type-string field--label-hidden field__item">Vaskuläre Biologie und Medizin</div> <div class="field field--name-field-facility field--type-string field--label-hidden field__item">Medizinische Fakultät Mannheim</div> <div class="field field--name-field-link field--type-link field--label-hidden field__item"><a href="https://www.umm.uni-heidelberg.de/medical-faculty-mannheim/research/focus-areas/vascular-biology-medicine/members/prof-dr-gergana-dobreva/">Gergana Dobreva</a></div> </div> </div> </article> <article data-history-node-id="206" role="article" lang="en" about="/index.php/en/prof-dr-ute-schepers" class="node node--type-people-profile node--view-mode-teaser"> <div class="node__content"> <div class="content-container"> <div class="header-container"> <h2> <a href="/index.php/en/prof-dr-ute-schepers" rel="bookmark"><span class="field field--name-title field--type-string field--label-hidden">Prof. Dr. Ute Schepers</span> </a> </h2> </div> <div class="field field--name-field-institute field--type-string field--label-hidden field__item">Institute of Functional Interfaces (IFG)</div> <div class="field field--name-field-facility field--type-string field--label-hidden field__item">Karlsruhe Institute of Technology</div> <div class="field field--name-field-link field--type-link field--label-hidden field__item"><a href="https://www.ifg.kit.edu/english/21_7474.php">Research Group Schepers</a></div> </div> </div> </article> </div> </div> Tue, 10 Dec 2019 14:46:14 +0000 Maria Garcia Hernandez 290 at https://heika-research.de Towards personalized therapy in retinal diseases - Development and evaluation of therapeutic performance parameters from OCT-Angiography images https://heika-research.de/en/research/medical-technology-health-mth/towards-personalized-therapy-retinal-diseases-development <span class="field field--name-title field--type-string field--label-hidden">Towards personalized therapy in retinal diseases - Development and evaluation of therapeutic performance parameters from OCT-Angiography images</span> <span class="field field--name-uid field--type-entity-reference field--label-hidden"><span lang="" about="/index.php/de/user/31" typeof="schema:Person" property="schema:name" datatype="" content="Maria Garcia Hernandez">Maria Garcia H…</span></span> <span class="field field--name-created field--type-created field--label-hidden">Do, 10.12.2020 - 15:18</span> <div class="clearfix text-formatted field field--name-field-summary field--type-text-long field--label-hidden field__item"><p><span><span><span><span lang="EN-US" xml:lang="EN-US" xml:lang="EN-US"><span>We hereby apply for a HEiKA project funding for a cooperation between the Karlsruhe Institute of Technology (KIT), Institute for Biomedical Technology (IBT) and the Department of Ophthalmology at the University Hospital of Heidelberg (UNI-HD). The proposed project is driven by the recent development of the Optical Coherence Tomography Angiography (OCTA) in Ophthalmology. For decades, vasculature was visualized by invasive dye-based angiography. Limitations of this gold standard include dye induced adverse effects and time-consuming procedures. Moreover, dye-based angiography is only a two-dimensional study focusing on the superficial retinal circulation, without the ability to visualize the deeper capillary structures. OCTA combines the OCT technology with doppler photometrie. It visualizes the retinal vessels and capillaries in different axial depths which allows physicians a novel three-dimensional insight into the microvascularization of the retina and the morphological changes during therapy. No parametrization of the vascularization or morphology is established so far, therefore the assessment of the patient's condition is subjective. Using machine vision tools to parametrize the degree of vascularization and further on the vascularization across multiple layers provides the physicians valuable objective information and has the potential to detect early changes and thus increase patient’s visual outcome. OCTA technology is a powerful tool with still un-exploit applications. The results of this research will be published from a clinical and computational point of view and will lead to sequential research questions. </span></span></span></span></span></p></div> <div class="field field--name-field-research-bridges field--type-entity-reference field--label-above"> <div class="field__label">Forschungsbrücken</div> <div class="field__items"> <div class="field__item"><a href="/index.php/en/research/medical-technology-health-mth" hreflang="en">Medical Technology for Health (MTH)</a></div> </div> </div> <div class="field field--name-field-start-date field--type-datetime field--label-above"> <div class="field__label">Start date</div> <div class="field__item"> <time datetime="2021-01-01T12:00:00Z" class="datetime">01.01.2021</time> </div> </div> <div class="field field--name-field-end-date field--type-datetime field--label-hidden field__item"><time datetime="2021-12-31T12:00:00Z" class="datetime">31.12.2021</time> </div> <div class="field field--name-field-contact-person field--type-entity-reference field--label-above"> <div class="field__label"><h3>Project management</h3></div> <div class="field__items"> <article data-history-node-id="323" role="article" lang="en" about="/en/prof-dr-med-ramin-khoramnia" class="node node--type-people-profile node--view-mode-teaser"> <div class="node__content"> <div class="content-container"> <div class="header-container"> <h2> <a href="/en/prof-dr-med-ramin-khoramnia" rel="bookmark"><span class="field field--name-title field--type-string field--label-hidden">Prof. Dr. med. Ramin Khoramnia</span> </a> </h2> </div> <div class="field field--name-field-institute field--type-string field--label-hidden field__item">Medical Faculty Heidelberg</div> <div class="field field--name-field-facility field--type-string field--label-hidden field__item">University of Heidelberg</div> <div class="field field--name-field-link field--type-link field--label-hidden field__item"><a href="https://www.klinikum.uni-heidelberg.de/personen/priv-doz-dr-med-ramin-khoramnia-febo-596">Ramin Khoramnia</a></div> </div> </div> </article> <article data-history-node-id="278" role="article" lang="en" about="/index.php/en/prof-dr-werner-nahm" class="node node--type-people-profile node--view-mode-teaser"> <div class="node__content"> <div class="content-container"> <div class="header-container"> <h2> <a href="/index.php/en/prof-dr-werner-nahm" rel="bookmark"><span class="field field--name-title field--type-string field--label-hidden">Prof. Dr. Werner Nahm</span> </a> </h2> </div> <div class="field field--name-field-function-1 field--type-string field--label-hidden field__item">Director Research Bridge MTH</div> <div class="field field--name-field-institute field--type-string field--label-hidden field__item">Institut für Biomedizinische Technik</div> <div class="field field--name-field-facility field--type-string field--label-hidden field__item">Karlsruher Institut für Technologie</div> <div class="field field--name-field-link field--type-link field--label-hidden field__item"><a href="https://www.ibt.kit.edu/Nahm.php">Werner Nahm</a></div> </div> </div> </article> </div> </div> Thu, 10 Dec 2020 14:18:32 +0000 Maria Garcia Hernandez 336 at https://heika-research.de Keep moving: unraveling the effects of rollator assistance on movement in older adults using a robotic rollator simulator https://heika-research.de/en/research/medical-technology-health-mth/keep-moving-unraveling-effects-rollator-assistance-movement <span class="field field--name-title field--type-string field--label-hidden">Keep moving: unraveling the effects of rollator assistance on movement in older adults using a robotic rollator simulator</span> <span class="field field--name-uid field--type-entity-reference field--label-hidden"><span lang="" about="/index.php/de/user/31" typeof="schema:Person" property="schema:name" datatype="" content="Maria Garcia Hernandez">Maria Garcia H…</span></span> <span class="field field--name-created field--type-created field--label-hidden">Do, 10.12.2020 - 15:21</span> <div class="clearfix text-formatted field field--name-field-summary field--type-text-long field--label-hidden field__item"><p><span><span><span>The ability to move independently is fundamental to a person’s quality of life. Unfortunately, difficulty in walking or getting up from a chair is common among elderly. In these cases, rollators are often provided to lean on to, thereby aiming to improve balance or to compensate for weak legs. However, it is unclear if rollators affect movement and actually reduce weight on the legs or improve balance. <span>These research gaps significantly delay further development of new and intelligent mobility systems. The steady increase in the aging population has given rise to the need for smart assistive devices to prolong independent living in </span>older adults.</span></span></span></p> <p><span><span><span>This proposal utilizes the unique availability of a state-of-the-art robot that can simulate rollator assistance, a fully equipped motion capture lab, as well as complementary expertise from HU and KIT <strong>to evaluate the effect of rollators on movement in young and elderly </strong>adults. We focus on sit-to-stand transitions and gait, as these movements are a prerequisite for many daily activities and often result in falls in older adults.</span></span></span></p> <p><span><span><span><span lang="EN-US" xml:lang="EN-US" xml:lang="EN-US">We aim to perform a collaborative experiment to analyze how rollator assistance affects movement as a function of <strong>levels of support</strong> (light touch vs complete support) and <strong>task difficulty</strong> (normal vs challenging situation). In accordance with their research focus, HU und KIT pursue individual but closely interwoven aims: </span></span></span></span></p> <ol> <li><span><span><span><strong><span lang="EN-US" xml:lang="EN-US" xml:lang="EN-US">HU</span></strong><span lang="EN-US" xml:lang="EN-US" xml:lang="EN-US">: Examine the effect of rollator support on <strong>posture</strong>, <strong>stability</strong> and <strong>joint loading</strong>.</span></span></span></span></li> <li><span><span><span><strong><span lang="EN-US" xml:lang="EN-US" xml:lang="EN-US">KIT</span></strong><span lang="EN-US" xml:lang="EN-US" xml:lang="EN-US">: Examine the effect of rollator support on <strong>motor coordination</strong>.</span></span></span></span></li> </ol> <p><span lang="EN-US" xml:lang="EN-US" xml:lang="EN-US"><span>This is the first comprehensive biomechanical analysis of the human-rollator interaction during everyday tasks using a specialized robotic device. The study will provide a rich dataset that will be co-published in international journals and will support a joint DFG or EU proposal for a more comprehensive outlook on the role of smart assistive devices in fall detection and/or prevention.</span></span></p></div> <div class="field field--name-field-research-bridges field--type-entity-reference field--label-above"> <div class="field__label">Forschungsbrücken</div> <div class="field__items"> <div class="field__item"><a href="/index.php/en/research/medical-technology-health-mth" hreflang="en">Medical Technology for Health (MTH)</a></div> </div> </div> <div class="field field--name-field-start-date field--type-datetime field--label-above"> <div class="field__label">Start date</div> <div class="field__item"> <time datetime="2021-01-01T12:00:00Z" class="datetime">01.01.2021</time> </div> </div> <div class="field field--name-field-end-date field--type-datetime field--label-hidden field__item"><time datetime="2021-12-31T12:00:00Z" class="datetime">31.12.2021</time> </div> <div class="field field--name-field-contact-person field--type-entity-reference field--label-above"> <div class="field__label"><h3>Project management</h3></div> <div class="field__items"> <article data-history-node-id="324" role="article" lang="en" about="/index.php/en/dr-lizeth-sloot" class="node node--type-people-profile node--view-mode-teaser"> <div class="node__content"> <div class="content-container"> <div class="header-container"> <h2> <a href="/index.php/en/dr-lizeth-sloot" rel="bookmark"><span class="field field--name-title field--type-string field--label-hidden">Dr. Lizeth Sloot</span> </a> </h2> </div> <div class="field field--name-field-institute field--type-string field--label-hidden field__item"> Institute of Computer Engineering</div> <div class="field field--name-field-facility field--type-string field--label-hidden field__item">University of Heidelberg</div> <div class="field field--name-field-link field--type-link field--label-hidden field__item"><a href="https://orb.iwr.uni-heidelberg.de/orb/?page_id=8">Lizeth Sloot</a></div> </div> </div> </article> <article data-history-node-id="239" role="article" lang="en" about="/index.php/en/prof-dr-thorsten-stein" class="node node--type-people-profile node--view-mode-teaser"> <div class="node__content"> <div class="content-container"> <div class="header-container"> <h2> <a href="/index.php/en/prof-dr-thorsten-stein" rel="bookmark"><span class="field field--name-title field--type-string field--label-hidden">Prof. Dr. Thorsten Stein</span> </a> </h2> </div> <div class="field field--name-field-institute field--type-string field--label-hidden field__item">Institute of Sports and Sports Science</div> <div class="field field--name-field-facility field--type-string field--label-hidden field__item">KIT</div> <div class="field field--name-field-link field--type-link field--label-hidden field__item"><a href="https://www.sport.kit.edu/english/3576_769.php">Thorsten Stein</a></div> </div> </div> </article> </div> </div> Thu, 10 Dec 2020 14:21:03 +0000 Maria Garcia Hernandez 337 at https://heika-research.de