81 results on '"Christian Metzger"'
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2. Adsorption geometry and electronic structure of a charge-transfer-complex: TTF-PYZ2 on Ag(110)
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Patrick Kretz, Kay Waltar, Yan Geng, Christian Metzger, Martin Graus, Achim Schöll, Friedrich Reinert, Shi-Xia Liu, Silvio Decurtins, Matthias Hengsberger, Jürg Osterwalder, and Luca Castiglioni
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orbital tomography ,charge-transfer ,surface physics ,molecular thin film ,photoemission tomography ,ARPES ,Science ,Physics ,QC1-999 - Abstract
We study electronic properties and adsorption geometries of the molecular charge-transfer-complex tetrathiafulvalene-dipyrazine on Ag(110). Using a combination of angle-resolved photoemission and electron diffraction, supported by DFT-based simulations, renders a comprehensive picture of this interesting system. We find low interaction between the substrate and the molecule and thus little changes of the molecular geometry upon adsorption, as compared to the free gas phase molecule. Five electronic valence states can be unambiguously assigned owing to their distinctive photoemission patterns. The molecules adsorb aligned with the Ag rows in the first layer, while they are slightly rotated in the second layer. Additional intensity of the molecular photoemission signal near the Fermi energy indicates partial charge-transfer into formerly unoccupied states, most likely of intermolecular origin.
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- 2021
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3. Reconstruction of dental roots for implant planning purposes: a retrospective computational and radiographic assessment of single-implant cases.
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Leonard Simon Brandenburg, Joachim Georgii, Rainer Schmelzeisen, Benedikt Christopher Spies, Felix Burkhardt, Marc Anton Fuessinger, René Marcel Rothweiler, Christian Gross 0005, Stefan Schlager, and Marc Christian Metzger
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- 2024
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4. Reconstruction of dental roots for implant planning purposes: a feasibility study.
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Leonard Simon Brandenburg, Lukas Berger, Steffen Jochen Schwarz, Hans Meine, Julia Vera Weingart, David Steybe, Benedikt Christopher Spies, Felix Burkhardt, Stefan Schlager, and Marc Christian Metzger
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- 2022
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5. Automated segmentation of head CT scans for computer-assisted craniomaxillofacial surgery applying a hierarchical patch-based stack of convolutional neural networks.
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David Steybe, Philipp Poxleitner, Marc Christian Metzger, Leonard Simon Brandenburg, Rainer Schmelzeisen, Fabian Bamberg, Phuong Hien Tran, Elias Kellner, Marco Reisert, and Maximilian Frederik Russe
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- 2022
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6. Robust Tumor Detection from Coarse Annotations via Multi-Magnification Ensembles.
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Mehdi Naouar, Gabriel Kalweit, Ignacio Mastroleo, Philipp Poxleitner, Marc Christian Metzger, Joschka Boedecker, and Maria Kalweit
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- 2023
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7. The statistical shape model as a quality assurance measure in the treatment of complex midface fractures: a case control study
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Marc Anton Fuessinger, Steffen Schwarz, Mathieu Gass, Philipp Poxleitner, Leonard Brandenburg, Stefan Schlager, and Marc Christian Metzger
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Statistical shape model (SSM) ,Computer-assisted surgery (CAS) ,Virtual defect reconstruction ,3D planning ,Virtual planning ,Bilateral midface fracture ,Specialties of internal medicine ,RC581-951 - Abstract
Abstract Background Complex bilateral midface fractures necessitate a surgically challenging procedure to preserve or restore the occlusion and the sensitive eye area. In this case control study, we aim to show the potential of a statistical shape model (SSM) for measuring the quality of the midface reconstruction, compared to the estimated preoperative situation. Methods An individualized SSM was postoperatively registered on 19 reconstructed complex bilateral midface fractures. Using this SSM, the distances from the simulated preoperative situation to the postoperative positions of the fracture segments were calculated. The fracture lines for Le Fort II, Le Fort III, and NOE fractures were chosen as reference points for the distance measurements. Results The SSM could be registered on all 19 complex bilateral midface fractures. All analyzed fractures showed a dorsal impaction (negative values) of the midface. Le Fort II fractures showed deviation values of –0.98 ± 4.6 mm, Le Fort III fractures showed values of –3.68 ± 3.6 mm, NOE type 2 fractures showed values of –0.25 ± 4.6 mm, and NOE type 1 fractures showed values of –0.25 ± 4.6 mm. Conclusions The SSM can be used to measure the quality of the achieved reduction of complex bilateral midface fractures based on the estimated preoperative situation. Trial registration DRKS00009719.
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- 2021
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8. Evaluation of computed tomography settings in the context of visualization and discrimination of low dose injections of a novel liquid soft tissue fiducial marker in head and neck imaging
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David Steybe, Philipp Poxleitner, Pit Jacob Voss, Marc Christian Metzger, Rainer Schmelzeisen, Fabian Bamberg, Suam Kim, and Maximilian Frederik Russe
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Head and neck cancer ,Tumor bed ,Fiducial markers ,Computed tomography ,Dual energy computed tomography ,Medical technology ,R855-855.5 - Abstract
Abstract Background Intraoperative incorporation of radiopaque fiducial markers at the tumor resection surface can provide useful assistance in identifying the tumor bed in postoperative imaging for RT planning and radiological follow-up. Besides titanium clips, iodine containing injectable liquid fiducial markers represent an option that has emerged more recently for this purpose. In this study, marking oral soft tissue resection surfaces, applying low dose injections of a novel Conformité Européenne (CE)-marked liquid fiducial marker based on sucrose acetoisobutyrate (SAIB) and iodinated SAIB (x-SAIB) was investigated. Methods Visibility and discriminability of low dose injections of SAIB/x-SAIB (10 µl, 20 µl, 30 µl) were systematically studied at different kV settings used in clinical routine in an ex-vivo porcine mandible model. Transferability of the preclinical results into the clinical setting and applicability of DE-CT were investigated in initial patients. Results Markers created by injection volumes as low as 10 µl were visible in CT imaging at all kV settings applied in clinical routine (70–120 kV). An injection volume of 30 µl allowed differentiation from an injection volume of 10 µl. In a total of 118 injections performed in two head and neck cancer patients, markers were clearly visible in 83% and 86% of injections. DE-CT allowed for differentiation between SAIB/x-SAIB markers and other hyperdense structures. Conclusions Injection of low doses of SAIB/x-SAIB was found to be a feasible approach to mark oral soft tissue resection surfaces, with injection volumes as low as 10 µl found to be visible at all kV settings applied in clinical routine. With the application of SAIB/x-SAIB reported for tumors of different organs already, mostly applying relatively large volumes for IGRT, this study adds information on the applicability of low dose injections to facilitate identification of the tumor bed in postoperative CT and on performance of the marker at different kV settings used in clinical routine.
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- 2021
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9. Ein Dashboard für die Studienberatung: Technische Infrastruktur und Studienverlaufsplanung im Projekt KI: edu.nrw.
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Frederik Baucks, Jonas Leschke, Christian Metzger, and Laurenz Wiskott
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- 2023
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10. Feasibility of Implant Strain Measurement for Assessing Mandible Bone Regeneration
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René Marcel Rothweiler, Sergej Zankovic, Leonard Simon Brandenburg, Marc-Anton Fuessinger, Christian Gross, Pit Jacob Voss, and Marc-Christian Metzger
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bone regeneration ,mandible reconstruction ,fracture ,strain measurement ,nonunion ,Mechanical engineering and machinery ,TJ1-1570 - Abstract
Nonunion is one of the most dreaded complications after operative treatment of mandible fractures or after mandible reconstruction using vascularized and non-vascularized bone grafts. Often diagnosis is made at advanced stage of disease when pain or complications occur. Devices that monitor fracture healing and bone regeneration continuously are therefore urgently needed in the craniomaxillofacial area. One promising approach is the strain measurement of plates. An advanced prototype of an implantable strain measurement device was tested after fixation to a locking mandible reconstruction plate in multiple compression experiments to investigate the potential functionality of strain measurement in the mandibular region. Compression experiments show that strain measurement devices work well under experimental conditions in the mandibular angle and detect plate deformation in a reliable way. For monitoring in the mandibular body, the device used in its current configuration was not suitable. Implant strain measurement of reconstruction plates is a promising methodical approach for permanent monitoring of bone regeneration and fracture healing in the mandible. The method helps to avoid or detect complications at an early point in time after operative treatment.
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- 2022
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11. Planning of skull reconstruction based on a statistical shape model combined with geometric morphometrics.
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Marc Anton Fuessinger, Steffen Jochen Schwarz, Carl-Peter Cornelius, Marc Christian Metzger, Edward Ellis, Florian Andreas Probst, Wiebke Semper-Hogg, Mathieu Gass, and Stefan Schlager
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- 2018
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12. Learning Visual Programming by Creating a Walkable Interactive Installation.
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Aristotelis Hadjakos, Heizo Schulze, André Düchting, Christian Metzger, Marc Ottensmann, Friederike Riechmann, Anna-Maria Schneider, and Michael Trappmann
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- 2015
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13. Donor site morbidity after computer assisted surgical reconstruction of the mandible using deep circumflex iliac artery grafts: a cross sectional study
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Leonard Simon Brandenburg, Pit Jacob Voss, Thomas Mischkowsky, Jan Kühle, Michael Andreas Ermer, Julia Vera Weingart, René Marcel Rothweiler, Marc Christian Metzger, Rainer Schmelzeisen, and Philipp Poxleitner
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Surgery ,General Medicine - Abstract
Background Computer Assisted Design and Computer Assisted Manufacturing (CAD/CAM) have revolutionized oncologic surgery of the head and neck. A multitude of benefits of this technique has been described, but there are only few reports of donor site comorbidity following CAD/CAM surgery. Methods This study investigated comorbidity of the hip following deep circumflex iliac artery (DCIA) graft raising using CAD/CAM techniques. A cross-sectional examination was performed to determine range of motion, muscle strength and nerve disturbances. Furthermore, correlations between graft volume and skin incision length with postoperative donor site morbidity were assessed using Spearman's rank correlation, linear regression and analysis of variance (ANOVA). Results Fifteen patients with a mean graft volume of 21.2 ± 5.7 cm3 and a mean incision length of 228.0 ± 30.0 mm were included. Patients reported of noticeable physical limitations in daily life activities (12.3 ± 11.9 weeks) and athletic activities (38.4 ± 40.0 weeks in mean) following surgery. Graft volume significantly correlated with the duration of the use of walking aids (R = 0.57; p = 0.033) and impairment in daily life activities (R = 0.65; p = 0.012). The length of the scar of the donor-site showed a statistically significant association with postoperative iliohypogastric nerve deficits (F = 4.4, p = 0.037). Patients with anaesthaesia of a peripheral cutaneous nerve had a larger mean scar length (280 ± 30.0 mm) than subjects with hypaesthesia (245 ± 10.1 mm) or no complaints (216 ± 27.7 mm). Conclusions Despite sophisticated planning options in modern CAD/CAM surgery, comorbidity of the donor site following iliac graft harvesting is still a problem. This study is the first to investigate comorbidity after DCIA graft raising in a patient group treated exclusively with CAD/CAM techniques. The results indicate that a minimal invasive approach in terms of small graft volumes and small skin incisions could help to reduce postoperative symptomatology. Trial registration Retrospectively registered at the German Clinical Trials Register (DRKS-ID: DRKS00029066); registration date: 23/05/2022
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- 2023
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14. Multiplex movie of concerted rotation of molecules on a 2D material
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Markus Scholz, Kiana Baumgärtner, Misa Nozaki, Marvin Reuner, Nils Wind, Masato Haniuda, Christian Metzger, Michael Heber, Dmytro Kutnyakhov, Federico Pressacco, Lukas Wenthaus, Keisuke Hara, Chul-Hee Min, Martin Beye, Friedrich Reinert, Friedrich Roth, Sanjoy Mahatha, Anders Madsen, Tim Wehling, Kaori Niki, Daria Popova-Gorelova, and Kai Rossnagel
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Condensed Matter - Materials Science ,Materials Science (cond-mat.mtrl-sci) ,FOS: Physical sciences - Abstract
Function is dynamic and originates at atomic interfaces. Combining the degrees of freedom of molecules with the peculiar properties of 2D quantum materials can create novel functionality. Here, we report the manipulation and ultrafast imaging of a unidirectional gearing motion in molecules on a 2D quantum material. To visualize and disentangle the intertwined structural and electronic dynamics of such a hybrid interface, we record a 'full molecular movie' by imaging the atomic positions, the evolution of the molecular orbital wavefunctions and the modification of electronic states of the substrate. In a multimodal investigation in a single setup, we disentangle dynamics in valence and core electrons of both the molecule and the surface with femtosecond and sub-{\aa}ngstr\"om precision. The ultrafast rotational motion is fueled by the transfer of hot holes into the molecules that results in 'supercharging' of the film. As hot carriers move through the interface, we track a transient modification of the frontier molecular orbitals and observe a chiral symmetry breaking associated with local structural rearrangements. Our calculations show that the 'supercharging' changes the interfacial potential energy landscape and triggers the gearing motion. The experiment offers all-in-one imaging of the electronic, molecular orbital, chemical and structural dynamics during the flow of charge and energy across the hybrid interface. Our approach provides detailed dynamical information on the mechanism underlying surface-adsorbed molecular gears and enables tailoring novel functionalities in hybrid active matter., Comment: 19 pages, 6 figures
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- 2023
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15. Effects of Red Blood Cell Transfusions on Distant Metastases of Oral Squamous Cell Carcinomas
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Leonard Simon Brandenburg, Marc Christian Metzger, Philipp Poxleitner, Pit Jacob Voss, Kirstin Vach, Johannes Hell, Konstantin Hasel, Julia Vera Weingart, Steffen Jochen Schwarz, and Michael Andreas Ermer
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oral squamous cell carcinoma ,Cancer Research ,stomatognathic diseases ,Oncology ,distant metastasis ,risk factor ,red blood cell transfusion ,Neoplasms. Tumors. Oncology. Including cancer and carcinogens ,Article ,RC254-282 - Abstract
Simple Summary Patients with distant metastasis of oral squamous cell carcinoma should be identified at an early stage of disease. In this study, we investigated if patients who received red blood cell transfusions are at risk for the development of distant metastasis. A positive correlation was found between RBC transfusion (HR = 2.42) and the occurrence of M+ in a multivariate regression model. Therefore, the administration of RBC can be considered as an independent prognostic factor and special attention should be paid to its detrimental effects in the perioperative management of OSCC patients. Abstract There is no consensus on the effect of red blood cell (RBC) transfusions on patients with oral squamous cell carcinoma (OSCC). The aim of this study was to investigate the association between RBC administration and the occurrence of distant metastases (M+) after surgical treatment of OSCC. All medical records of patients who underwent primary surgery for OSCC in our department (2003–2019) were analyzed retrospectively (n = 609). Chi and Cox regression models were used to analyze the influence of transfusion on the development of M+, and survival rates. Kaplan–Meier curves were used for graphical presentation. A multitude of patient-specific factors showed a statistical impact in univariate analysis (transfusion, age, gender, diabetes, pT, pN, L, V, Pn, G, UICC, adjuvant therapy, free microvascular transplant, preoperative hemoglobin level). Transfusion status and pN stage were the only variables that showed a significant correlation to M+ in the multivariate Cox model. The hazard ratios for the occurrence of M+ were 2.42 for RBC transfusions and 2.99 for pN+. Administration of RBC transfusions was identified as a significant prognostic parameter for the occurrence of distant metastases after surgical treatment of OSCC. Hence, the administration of RBC transfusions should be considered carefully in the perioperative management.
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- 2022
16. Ambient Energy Scavenging for Sensor-Equipped RFID Tags in the Cold Chain.
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Christian Metzger, Florian Michahelles, and Elgar Fleisch
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- 2007
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17. Making Radio Frequency Identification Visible - A Watchdog Tag.
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Christian Metzger, Christian Floerkemeier, Philippe Bourquin, and Elgar Fleisch
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- 2007
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18. Weight-Sensitive Foam to Monitor Product Availability on Retail Shelves.
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Christian Metzger, Jan Meyer, Elgar Fleisch, and Gerhard Tröster
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- 2007
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19. A Wearable Interface for Topological Mapping and Localization in Indoor Environments.
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Grant Schindler, Christian Metzger, and Thad Starner
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- 2006
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20. FreeDigiter: A Contact-Free Device for Gesture Control.
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Christian Metzger, Matt Anderson, and Thad Starner
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- 2004
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21. Two ways to die: Species dependent PCD modes in grapevine cells
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Peijie Gong, Islam M. Khattab, Andrzej Kaźmierczak, Christian Metzger, Xin Zhu, Qiong Liu, René Glenz, Frank Waller, and Peter Nick
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Genetics ,Plant Science ,General Medicine ,Agronomy and Crop Science - Published
- 2023
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22. The impact of false-negative reads on the performance of RFID-based shelf inventory control policies.
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Christian Metzger, Frédéric Thiesse, Stanley B. Gershwin, and Elgar Fleisch
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- 2013
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23. Design and development of a virtual anatomic atlas of the human skull for automatic segmentation in computer-assisted surgery, preoperative planning, and navigation.
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Marc Christian Metzger, G. Bittermann, Larissa Dannenberg, Rainer Schmelzeisen, Nils-Claudius Gellrich, Bettina Hohlweg-Majert, and C. Scheifele
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- 2013
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24. Simultaneous cutting of coupled tetrahedral and triangulated meshes and its application in orbital reconstruction.
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Marc Christian Metzger, Marc Gissler, Matthias Asal, and Matthias Teschner
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- 2009
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25. Orthopedic rehabilitation after computer assisted surgical reconstruction of the mandible using deep circumflex iliac artery grafts – a cross sectional study
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Leonard Simon Brandenburg, Pit Jacob Voss, Thomas Mischkowsky, Jan Kühle, Michael Andreas Ermer, Julia Vera Weingart, René Marcel Rothweiler, Marc Christian Metzger, Rainer Schmelzeisen, and Philipp Poxleitner
- Abstract
Background: Computer Assisted Design and Computer Assisted Manufacturing (CAD/CAM) has revolutionized oncologic surgery of the head and neck. A multitude of benefits of this technique has been described, but there are only few reports of donor site comorbidity following CAD/CAM surgery. Methods: This study investigated comorbidity of the hip following deep circumflex iliac artery (DCIA) graft raising using CAD/CAM techniques. A cross-sectional examination was performed to determine range of motion, muscle strength and nerve disturbances. Furthermore, correlations between graft volume and skin incision length with postoperative orthopedic rehabilitation were assessed using Spearman's rank correlation, linear regression and analysis of variance (ANOVA).Results: Fifteen patients with a mean graft volume of 21.2 ± 5.7 cm3 and a mean incision length of 228.0 ± 30.0 mm were included. Patients reported of noticeable physical limitations in daily life activities (12.3 ± 11.9 weeks) and athletic activities (38.4 ± 40.0 weeks in mean) following surgery. Graft volume significantly correlated with the duration of the use of walking aids (R = 0.57; p = 0.033) and impairment in daily life activities (R = 0.65; p = 0.012). The length of the scar of the donor-site showed a statistically significant association with postoperative iliohypogastric nerve deficits (F = 4.4, p = 0.037). Patients with anaesthaesia of a peripheral cutaneous nerve had a larger mean scar length (280 ± 30.0 mm) than subjects with hypaesthesia (245 ± 10.1 mm) or no complaints (216 ± 27.7 mm). Conclusions: Despite sophisticated planning options in modern CAD/CAM surgery comorbidity of the donor site following microsurgery is still a problem. This study is the first to investigate comorbidity after DCIA graft raising in a patient group treated exclusively with CAD/CAM techniques. The results indicate that a minimal invasive approach in terms of small graft volumes and small skin incisions could help to reduce postoperative symptomatology.Trial registration: Retrospectively registered at the German Clinical Trials Register (DRKS-ID: DRKS00029066); registration date: 23/05/2022.
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- 2022
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26. A Novel Method for Digital Reconstruction of the Mucogingival Borderline in Optical Scans of Dental Plaster Casts
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Leonard Simon Brandenburg, Stefan Schlager, Lara Sophie Harzig, David Steybe, René Marcel Rothweiler, Felix Burkhardt, Benedikt Christopher Spies, Joachim Georgii, and Marc Christian Metzger
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statistical shape model ,mucogingival borderline ,implant planning ,soft tissue dimensions ,virtual planning ,General Medicine - Abstract
Adequate soft-tissue dimensions have been shown to be crucial for the long-term success of dental implants. To date, there is evidence that placement of dental implants should only be conducted in an area covered with attached gingiva. Modern implant planning software does not visualize soft-tissue dimensions. This study aims to calculate the course of the mucogingival borderline (MG-BL) using statistical shape models (SSM). Visualization of the MG-BL allows the practitioner to consider the soft tissue supply during implant planning. To deploy an SSM of the MG-BL, healthy individuals were examined and the intra-oral anatomy was captured using an intra-oral scanner (IOS). The empirical anatomical data was superimposed and analyzed by principal component analysis. Using a Leave-One-Out Cross Validation (LOOCV), the prediction of the SSM was compared with the original anatomy extracted from IOS. The median error for MG-BL reconstruction was 1.06 mm (0.49–2.15 mm) and 0.81 mm (0.38–1.54 mm) for the maxilla and mandible, respectively. While this method forgoes any technical work or additional patient examination, it represents an effective and digital method for the depiction of soft-tissue dimensions. To achieve clinical applicability, a higher number of datasets has to be implemented in the SSM.
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- 2022
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27. Creating an anatomical wax-up in partially edentulous patients by means of a statistical shape model
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Leonard Simon, Brandenburg, Steffen Jochen, Schwarz, Benedikt Christopher, Spies, Julia Vera, Weingart, Joachim, Georgii, Britta A, Jung, Felix, Burkhardt, Stefan, Schlager, and Marc Christian, Metzger
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Dental Implants ,Models, Statistical ,Crowns ,Humans ,Mouth, Edentulous ,Prosthodontics - Abstract
Creating wax-ups of missing teeth for backward planning in implant surgery is a complex and time-consuming process. To facilitate implant-planning procedures, the automatic generation of a virtual wax-up would be useful. In the present study, the reconstruction of missing teeth in partially edentulous patients was performed automatically using newly developed software. The accuracy was investigated in order to test its clinical applicability.This study presents a new method for creating an automatic virtual wax-up, which could serve as a basic tool in modern implant-planning procedures. First, a statistical shape model (SSM) based on 76 maxillary and mandibular arch scans from dentally healthy individuals was generated. Then, artificially generated tooth gaps were reconstructed. The accuracy of the workflow was evaluated on a separate testing sample of 10 individuals with artificially created tooth gaps given as a median deviation, in millimeters. Scans of three clinical cases with partial edentulism were equally reconstructed using the SSM and compared with the final prosthodontic work.The reconstruction of the artificial tooth gaps could be performed with the following median reconstruction accuracy: gap 21 with 0.15 mm; gap 27 with 0.20 mm; gap 34 with 0.22 mm: gap 36 with 0.22 mm; gaps 12 to 22 with 0.22 mm; gaps 34 to 36 with 0.22 mm. A scenario for an almost edentulous mandible with all teeth missing except teeth 33 and 43 could be reconstructed with a median reconstruction accuracy of 0.37 mm. The median tooth gap deviation of the SSM-based reconstruction in clinical cases differed from the final inserted prosthodontic teeth by 0.49 to 0.86 mm in median.A first feasibility of creating virtual wax-ups using an SSM could be shown. Artificially generated tooth gaps could be reconstructed close to the original with the proposed workflow. In the clinical cases, the SSM proposes an anatomical reconstruction, which does not yet consider prosthodontic aspects. To obtain clinical use, contact with antagonist teeth must be considered and more training data must be implemented. However, the presented method offers a fast and viable way for the approximate placement of missing crowns. This could be used in a digital planning workflow when implant position must be determined. (Int J Comput Dent 2022;25(4):349-0; doi: 10.3290/j.ijcd.b2599407).
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- 2022
28. Automated segmentation of head CT scans for computer-assisted craniomaxillofacial surgery applying a hierarchical patch-based stack of convolutional neural networks
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David Steybe, Philipp Poxleitner, Marc Christian Metzger, Leonard Simon Brandenburg, Rainer Schmelzeisen, Fabian Bamberg, Phuong Hien Tran, Elias Kellner, Marco Reisert, and Maximilian Frederik Russe
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Computers ,Biomedical Engineering ,Health Informatics ,General Medicine ,Computer Graphics and Computer-Aided Design ,Computer Science Applications ,Imaging, Three-Dimensional ,Image Processing, Computer-Assisted ,Humans ,Radiology, Nuclear Medicine and imaging ,Surgery ,Computer Vision and Pattern Recognition ,Neural Networks, Computer ,Tomography, X-Ray Computed - Abstract
Purpose Computer-assisted techniques play an important role in craniomaxillofacial surgery. As segmentation of three-dimensional medical imaging represents a cornerstone for these procedures, the present study was aiming at investigating a deep learning approach for automated segmentation of head CT scans. Methods The deep learning approach of this study was based on the patchwork toolbox, using a multiscale stack of 3D convolutional neural networks. The images were split into nested patches using a fixed 3D matrix size with decreasing physical size in a pyramid format of four scale depths. Manual segmentation of 18 craniomaxillofacial structures was performed in 20 CT scans, of which 15 were used for the training of the deep learning network and five were used for validation of the results of automated segmentation. Segmentation accuracy was evaluated by Dice similarity coefficient (DSC), surface DSC, 95% Hausdorff distance (95HD) and average symmetric surface distance (ASSD). Results Mean for DSC was 0.81 ± 0.13 (range: 0.61 [mental foramen] – 0.98 [mandible]). Mean Surface DSC was 0.94 ± 0.06 (range: 0.87 [mental foramen] – 0.99 [mandible]), with values > 0.9 for all structures but the mental foramen. Mean 95HD was 1.93 ± 2.05 mm (range: 1.00 [mandible] – 4.12 mm [maxillary sinus]) and for ASSD, a mean of 0.42 ± 0.44 mm (range: 0.09 [mandible] – 1.19 mm [mental foramen]) was found, with values Conclusion In this study, high accuracy of automated segmentation of a variety of craniomaxillofacial structures could be demonstrated, suggesting this approach to be suitable for the incorporation into a computer-assisted craniomaxillofacial surgery workflow. The small amount of training data required and the flexibility of an open source-based network architecture enable a broad variety of clinical and research applications.
- Published
- 2021
29. Reconstruction of dental roots for implant planning purposes: a feasibility study
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Leonard Simon Brandenburg, Lukas Berger, Steffen Jochen Schwarz, Hans Meine, Julia Vera Weingart, David Steybe, Benedikt Christopher Spies, Felix Burkhardt, Stefan Schlager, and Marc Christian Metzger
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Dental Implants ,Biomedical Engineering ,Health Informatics ,General Medicine ,Mandible ,Cone-Beam Computed Tomography ,Computer Graphics and Computer-Aided Design ,Computer Science Applications ,Imaging, Three-Dimensional ,Surgery, Computer-Assisted ,Maxilla ,Computer-Aided Design ,Feasibility Studies ,Humans ,Radiology, Nuclear Medicine and imaging ,Surgery ,Computer Vision and Pattern Recognition - Abstract
Purpose Modern virtual implant planning is a time-consuming procedure, requiring a careful assessment of prosthetic and anatomical factors within a three-dimensional dataset. In order to facilitate the planning process and provide additional information, this study examines a statistical shape model (SSM) to compute the course of dental roots based on a surface scan. Material and methods Plaster models of orthognathic patients were scanned and superimposed with three-dimensional data of a cone-beam computer tomography (CBCT). Based on the open-source software “R”, including the packages Morpho, mesheR, Rvcg and RvtkStatismo, an SSM was generated to estimate the tooth axes. The accuracy of the calculated tooth axes was determined using a leave-one-out cross-validation. The deviation of tooth axis prediction in terms of angle or horizontal shift is described with mean and standard deviation. The planning dataset of an implant surgery patient was additionally analyzed using the SSM. Results 71 datasets were included in this study. The mean angle between the estimated tooth-axis and the actual tooth-axis was 7.5 ± 4.3° in the upper jaw and 6.7 ± 3.8° in the lower jaw. The horizontal deviation between the tooth axis and estimated axis was 1.3 ± 0.8 mm close to the cementoenamel junction, and 0.7 ± 0.5 mm in the apical third of the root. Results for models with one missing tooth did not differ significantly. In the clinical dataset, the SSM could give a reasonable aid for implant positioning. Conclusions With the presented SSM, the approximate course of dental roots can be predicted based on a surface scan. There was no difference in predicting the tooth axis of existent or missing teeth. In clinical context, the estimation of tooth axes of missing teeth could serve as a reference for implant positioning. However, a higher number of training data must be achieved to obtain increasing accuracy.
- Published
- 2021
30. Analyzing the Fitting of Novel Preformed Osteosynthesis Plates for the Reduction and Fixation of Mandibular Fractures
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Marc Anton Fuessinger, Mathieu Gass, Caroline Woelm, Carl-Peter Cornelius, Ruediger M. Zimmerer, Philipp Poxleitner, Stefan Schlager, and Marc Christian Metzger
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mandibular fractures ,preformed osteosynthesis plates ,virtual analysis ,Medicine ,General Medicine ,Article - Abstract
Purpose: The known preformed osteosynthesis plates for the midface are helpful tools for a precise and fast fixation of repositioned fractures. The purpose of the current study is to analyze the precision of newly developed prototypes of preformed osteosynthesis plates for the mandible. Methods: Four newly designed preformed osteosynthesis plates, generated by a statistical shape model based on 115 CT scans, were virtually analyzed. The used plates were designed for symphyseal, parasymphyseal, angle, and condyle fractures. Each type of plate has three different sizes. For analysis, the shortest distance between the plate and the bone surface was measured, and the sum of the plate-to-bone distances over the whole surface was calculated. Results: A distance between plate and bone of less than 1.5 mm was defined as sufficient fitting. The plate for symphyseal fractures showed good fitting in 90% of the cases for size M, and in 84% for size L. For parasymphyseal fractures, size S fits in 80%, size M in 68%, and size L in 65% of the cases. Angle fractures with their specific plate show good fitting for size S in 53%, size M in 60%, and size L in 47%. The preformed plate for the condyle part fits for size S in 75%, for size M in 85%, and for size L in 74% of the cases. Conclusion: The newly developed mandible plates show sufficient clinical fitting to ensure adequate fracture reduction and fixation.
- Published
- 2021
31. Chitosan triggers actin remodelling and activation of defence genes that is repressed by calcium influx in grapevine cells
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Karwan Gafoor Sofi, Christian Metzger, Michael Riemann, and Peter Nick
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Chitosan ,Genetics ,Calcium ,Vitis ,Plant Science ,General Medicine ,Agronomy and Crop Science ,Actins ,Plant Proteins - Abstract
Defence to pathogens must be specific. In the past, we have dissected early signalling deployed by bacterial elicitors in a grapevine cell system. In the current work, we asked, how defence of fungi differs. Fungal diseases of grapevine pose great challenges for global viticulture and require massive plant protection measures. Plant cells are able to sense chitin, a central component of fungal cell walls and respond by activation of basal defence. We, therefore mapped early defence responses evoked by chitosan, a chitin fragment able to bind to chitin receptors. We found an activation of calcium influx, monitored by extracellular alkalinisation due to a co-transport of protons, remodelling of actin (but not of microtubules), and the activation of transcripts for phytoalexin synthesis, jasmonate-signalling, salicylate signalling, and chitinase. Interestingly, Gadolinium, an inhibitor of calcium influx, can inhibit extracellular alkalinisation in response to chitosan, while the induction of the phytoalexin synthesis transcripts was specifically promoted. In contrast, both DMSO and benzyl alcohol, compounds known to modulate membrane fluidity, partially inhibited the transcript responses to chitosan. We discuss these data with a model, where chitosan deploys signalling culminating in activation of defence related transcripts, but at the same time activates calcium influx that negatively feeds back on the same signal chain, which might be a mechanism to achieve a temporal signature that is rapid, but transient.
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- 2023
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32. Cranial reconstruction evaluation - comparison of European statistical shape model performance on Chinese dataset
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Marc Anton, Fuessinger, Marc Christian, Metzger, Rene, Rothweiler, Leonard Simon, Brandenburg, and Stefan, Schlager
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Endocrinology, Diabetes and Metabolism ,Orthopedics and Sports Medicine - Abstract
Morphological variability of the skull is an important consideration for cranioplasty and implant design. Differences in morphology of the skull based on the ethnicity are known. In a previous study we could show the accuracy and benefits of virtual reconstructions based on a statistical shape model (SSM) for neurocranial defects. As the SSM is trained on European data, the question arises how well this model fares when dealing with patients with a different ethnic background. In this study we aim to evaluate the accuracy and applicability of our proposed method when deploying a cranial SSM generated from European data to estimate missing parts of the neurocranium in a Chinese population.We used the same data and methods as in our previous study and compared the outcomes when applied to Chinese individuals. A large unilateral defect on the right side and a bilateral defect were created. The outer surface of the cranial table was reconstructed from CT scans, meshed with triangular elements, and registered to a template. Principal component analysis together with Thin Plate Spines (TPS) deformation was applied to quantify modes of variation. The mesh to mesh distances between the original defects´ surfaces and the reconstructed surface were computed.Comparing the Chinese test group with the European control group, regarding the entire defect the analysis shows no significant difference for unilateral defects (test vs. control group/0.46 mm ± vs. 0.44 mm). Reconstruction of bilateral defects exhibited only in slightly higher prediction errors than those of unilateral defects (0.49 mm ± vs. 0.45 mm).The proposed method shows a high accuracy that seems to be ethnical independent - with low error margins for virtual skull reconstruction and implant design.Clinical relevance: Metallic objects may severely impact image quality in several CBCT devices.
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- 2022
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33. Considerations for Healthcare Applications in a Platform as a Service Environment.
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Andreas Holubek and Christian Metzger
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- 2012
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34. Anatomy of the Orbits: Skeletal Features and Some Notes on the Periorbital Lining
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Carl Peter, Cornelius, Florian, Probst, Marc Christian, Metzger, and Peter J J, Gooris
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Face ,Humans ,Orbit - Published
- 2021
35. Atlas der digitalen Volumentomografie
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Alexander Gröbe, Arndt Klocke, Christian R. Habermann, Reinhard E Friedrich, Frank Müller, Carl-Peter Cornelius, Marc Christian Metzger, Wolfgang Lehmann, Steffen Maune, Max Heiland, D Schulze, Rainer Schmelzeisen, Markus Preis, Wiebke Semper-Hogg, Markus Hess, Sebastian Bürklein, Michael Ehrenfeld, Ole Jung, Ralf Smeets, Nico Vrijens, Clarissa Precht, Jochen Franke, Paul Alfred Grützner, A. Mousli, Henning Hanken, Florian Andreas Probst, Till Orla Klatte, Jörg Schipper, Thomas Ebinger, and Levi Matthies
- Published
- 2021
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36. Ultrafast molecular orbital tomography of a pentacene thin film using time-resolved momentum microscopy at a free-electron laser
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Chul-Hee Min, Günter Brenner, Kiana Baumgärtner, Roman Shayduk, Serguei L. Molodtsov, Federico Pressacco, Christian Metzger, Chan Kim, Anders Madsen, Mario Reiser, Michael Heber, M. Izquierdo, Thiago R. F. Peixoto, Friedrich Reinert, Friedrich Roth, Markus Scholz, D. Kutnyakhov, Wilfried Wurth, Achim Schoell, and Wei Lu
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Pentacene ,Momentum (technical analysis) ,chemistry.chemical_compound ,Materials science ,chemistry ,Microscopy ,Free-electron laser ,Molecular orbital ,Tomography ,Thin film ,Molecular physics ,Ultrashort pulse - Abstract
Understanding and control of photon-induced dynamics of molecules on solid surfaces, including atomic rearrangements as well as charge transfer and non-equilibrium electron dynamics, are of essential importance for surface chemistry but also for the development of new devices. We use time-resolved momentum microscopy at a free-electron laser (FEL) and extend orbital tomography to time-resolved imaging of electronic wave functions of excited molecular orbitals. This technique will provide unprecedented insight into the ultrafast interplay between structural and electronic dynamics. In this work we prove general applicability and establish the experimental conditions at FEL sources to minimize space charge effects and radiation damage. We investigate a bilayer pentacene film on Ag(110) by optical laser pump and FEL probe experiments. From the momentum microscopy signal, we obtain time-dependent momentum maps of the molecular valence states that can be related to the molecular initial states by simulations of the involved photoemission matrix elements. A state above the Fermi level is identified which is temporarily occupied after optical excitation.
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- 2020
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37. Plane-wave final state for photoemission from nonplanar molecules at a metal-organic interface
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Achim Schöll, Christian Metzger, Manuel Grimm, M. Schwendt, Daniel Lüftner, Friedrich Reinert, Peter Puschnig, Vitaliy Feyer, Giovanni Zamborlini, and Martin Graus
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Surface (mathematics) ,Physics ,Orientation (vector space) ,Condensed Matter::Materials Science ,Monolayer ,Plane wave ,Molecule ,ddc:530 ,Molecular orbital ,Density functional theory ,Charge (physics) ,Physics::Chemical Physics ,Molecular physics - Abstract
In recent years, the method of orbital tomography has been a useful tool for the analysis of a variety of molecular systems. However, the underlying plane-wave final state has been largely expected to be applicable to planar molecules only. Here, we demonstrate on photoemission data from the molecule ${\mathrm{C}}_{60}$ adsorbed on Ag(110) that it can indeed be a valid approximation for truly three-dimensional molecules at a metal-organic interface. A comparison of the experimental data supported by density functional theory (DFT) calculations of the full interface and simulations of the photoemission process with a more exact final state enables the determination of the adsorption geometry and orientation of the ${\mathrm{C}}_{60}$ molecules in a monolayer on the Ag(110) surface. Additionally, charge transfer into the molecules is used to confirm the lifting in degeneracy of the ${t}_{\text{1u}}$ molecular orbitals as predicted by DFT calculations.
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- 2020
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38. Successful Management of Cleft Lip and Palate Malformation without Pre-Surgical Infant Orthopedics.
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Jochen, Schwarz Steffen, Simon, Brandenburg Leonard, Vera, Weingart Julia, Wiebke, Schupp, Anton, Füssinger Marc, Aurelia, Stocker Sophia, Christian, Metzger Marc, Leonard Simon, Brandenburg, Marc Anton, Füssinger, Marc Christian, Metzger, Schwarz, Steffen Jochen, Brandenburg, Leonard Simon, Weingart, Julia Vera, Schupp, Wiebke, Füssinger, Marc Anton, Stocker, Sophia Aurelia, Metzger, Marc Christian, and Füssinger, Marc Anton
- Published
- 2021
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39. The Statistical shape model as a quality assurance measure in the treatment of complex midface fractures: A Case control study
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Fuessinger, Marc Anton, primary, Steffen, Schwarz, additional, Mathieu, Gass, additional, Philipp, Poxleitner, additional, Leonard, Brandenburg, additional, Stefan, Schlager, additional, and Christian, Metzger Marc, additional
- Published
- 2020
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40. Alterstraumatologie im Gesichtsschädelbereich
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Gerson Mast, Marc-Christian Metzger, Florian Andreas Probst, Carl-Peter Cornelius, Philipp Goetz, and Michael Ehrenfeld
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03 medical and health sciences ,0302 clinical medicine ,030220 oncology & carcinogenesis ,030206 dentistry - Abstract
ZusammenfassungCMF-Traumen im Alter 65+ sind durch besondere Merkmale gekennzeichnet: Lokalisation und Frakturmuster, Stand des Involutionsprozesses mit Abnahme von Knochenquantität und -qualität, Begleitverletzungen, altersassoziierte physische und psychische Funktionseinbußen und präexistente Komorbiditäten. Der Stand des Wissens und aktuelle bevölkerungsbezogene Daten dieser Variablen werden zu Anfang dieser Übersicht dargestellt. Vor diesem Hintergrund wird dann zu den verschiedenen Frakturen und Frakturtypen in den einzelnen Regionen des Gesichtsschädelskeletts Stellung genommen und die Indikation zu einem konservativen oder operativen Prozedere in den Alterspopulationen diskutiert. Spezielle Aufmerksamkeit kommt dabei Fraktursituationen bei Zahnlosigkeit und Atrophie im Ober- und/oder Unterkiefer zu. Innerhalb des weitgesteckten Gesamtspektrums der Frakturszenarien haben schonende, situationsadaptierte, ggf. auch unkonventinelle Lösungen Priorität vor Standardtherapieverfahren. Neue Techniken wie computerassistierte Chirurgie und patientenspezifische Implantate spielen eine immer größere Rolle und werden an Einzelbeispielen demonstriert. Betont werden muss, dass die physischen Reserven und nötigenfalls die geriatrietypische Multimorbidität jedes Patienten individuell einzuschätzen ist und vorrangige Bedeutung vor dem kalendarischen Lebensalter hat.
- Published
- 2017
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41. Clinical analysis of MatrixMANDIBLE Preformed Reconstruction Plate design
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Florian Andreas Probst, Marc Christian Metzger, Kirstin Vach, Rainer Schmelzeisen, Carl-Peter Cornelius, Martin Zens, and Fabian Duttenhoefer
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Adult ,Male ,medicine.medical_specialty ,Radiography ,Bone Screws ,Oral Surgical Procedures ,Mandible ,03 medical and health sciences ,0302 clinical medicine ,Bone plate ,Radiography, Dental ,medicine ,Humans ,Aged ,Retrospective Studies ,Aged, 80 and over ,Titanium ,Orthodontics ,business.industry ,Equipment Design ,030206 dentistry ,Middle Aged ,Plastic Surgery Procedures ,Surgery ,Bone screws ,Otorhinolaryngology ,Terminal (electronics) ,030220 oncology & carcinogenesis ,Female ,Free form ,Oral Surgery ,business ,Bone Plates ,Statistical correlation - Abstract
MatrixMANDIBLE Preformed Reconstruction Plates (MMPRPs) were developed to overcome laborious bending procedures of conventional reconstruction plates. The design comprises three sizes with a nonbendable centerpiece and two bendable sections (proximal and distal). According to the surgical protocol unnecessary parts are trimmed after the last used screw hole. In the present retrospective study postoperative radiographs from 130 patients (average age 63 years) that received treatment with MMPRPs were assessed. There was no statistical correlation between plate-size, location (left/right) or age. 82.98% of the small and 91.80% of the medium MMPRPs were trimmed by at least the terminal screw hole of the ramus part. In all patients receiving a large MMPRP, the terminal screw hole of the ramus was unused accordingly all inserted large MMPRPs were trimmed by at least the terminal screw hole. The majority of the bridged defects were located within the area of the body indicating a feasible plate design. With the emergence of solid free form fabrication of Ti-alloys and economic need to reduce the waste of resources this study may help to further improve the MMPRP design and prevent the loss of medical-grade titanium.
- Published
- 2017
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42. Examining Reported Side Effect Rates in Varicella and Hepatitis A Vaccines When Administered in Same vs. Different Locations in Pediatric Patients
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Conor Cronin, Daniel Pierce, Christian Metzger, and Grant Wallenfelsz
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medicine.medical_specialty ,Side effect ,business.industry ,Internal medicine ,Hepatitis A vaccine ,Medicine ,business - Published
- 2019
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43. Three-dimensional tomographic imaging of molecular orbitals by photoelectron momentum microscopy
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Martin Graus, Vitaliy Feyer, Pascal Nigge, Achim Schöll, F. Reinert, Christian Metzger, and Manuel Grimm
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Physics ,Tomographic reconstruction ,Solid-state physics ,Atoms in molecules ,Electron ,Condensed Matter Physics ,01 natural sciences ,Molecular physics ,Synchrotron ,010305 fluids & plasmas ,Electronic, Optical and Magnetic Materials ,law.invention ,Atomic orbital ,law ,0103 physical sciences ,Molecular orbital ,Electron configuration ,010306 general physics - Abstract
As one of the fundamental concepts of quantum mechanics, electrons in atoms and molecules are assigned to respective orbitals. The geometric distribution of these orbitals is immediately connected to many chemical and physical properties of the system. Consequently, measuring electron orbitals directly has been highly desired. In this study, we demonstrate how a combination of a photoemission electron microscope with a synchrotron UV-light source can be utilised to record a three-dimensional set of tomographic data and present a detailed procedure to reconstruct the orbitals under investigation in real space.
- Published
- 2019
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44. Molecular orbital imaging beyond the first monolayer: Insights into the pentacene/Ag(110) interface
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Christian Metzger, Matteo Jugovac, Achim Schöll, Manuel Grimm, Martin Graus, Vitaliy Feyer, Giovanni Zamborlini, and Friedrich Reinert
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Materials science ,02 engineering and technology ,021001 nanoscience & nanotechnology ,01 natural sciences ,Molecular physics ,Pentacene ,Momentum ,chemistry.chemical_compound ,Molecular geometry ,Tilt (optics) ,chemistry ,0103 physical sciences ,Monolayer ,Molecule ,Molecular orbital ,010306 general physics ,0210 nano-technology ,Layer (electronics) - Abstract
Understanding the molecular geometry at interfaces is not only of importance for optimizing contact properties but also sets the basis in energy alignment in multilayer samples. Here we present a method to determine the tilt angle of molecular compounds by a combination of the orbital imaging technique with photoemission matrix element calculations. By simulating different tilt angles of isolated molecules and comparing the resulting photoemission intensity distribution with momentum maps measured on molecular multilayers, one is able to determine the molecules' tilt angles for each separate layer independently from one another.
- Published
- 2018
- Full Text
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45. Algorithms and image formation in orbital tomography
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Luca Castiglioni, Matthias Hengsberger, Giovanni Zamborlini, Christian Metzger, Manuel Grimm, Tatiana Latychevskaia, Jürg Osterwalder, Matteo Jugovac, Pavel Kliuiev, Achim Schöll, and University of Zurich
- Subjects
Physics ,Image formation ,Chemical Physics (physics.chem-ph) ,Background subtraction ,3104 Condensed Matter Physics ,530 Physics ,FOS: Physical sciences ,2504 Electronic, Optical and Magnetic Materials ,Image processing ,02 engineering and technology ,Mutual information ,10192 Physics Institute ,Computational Physics (physics.comp-ph) ,021001 nanoscience & nanotechnology ,01 natural sciences ,Superposition principle ,Physics - Chemical Physics ,0103 physical sciences ,Molecular orbital ,Tomography ,010306 general physics ,0210 nano-technology ,Phase retrieval ,Physics - Computational Physics ,Algorithm - Abstract
Orbital tomography has recently been established as a technique to reconstruct molecular orbitals directly from photoemission data using iterative phase retrieval algorithms. In this work, we present a detailed description of steps for processing of the photoemission data followed by an improved iterative phase retrieval procedure and the interpretation of reconstructed two-dimensional orbital distributions. We address the issue of background subtraction by suggesting a signal restoration routine based on the maximization of mutual information algorithm and solve the problem of finding the geometrical center in the reconstruction by using a tight-centered object support in a two-step phase retrieval procedure. The proposed image processing and improved phase retrieval procedures are used to reconstruct the highest occupied molecular orbital of pentacene on Ag(110), using photoemission data only. The results of the reconstruction agree well with the density functional theory simulation, modified to comply with the experimental conditions. By comparison with photoelectron holography, we show that the reconstructed two-dimensional orbital distribution can be interpreted as a superposition of the in-focus orbital distribution evaluated at the $z=0$ plane and out-of-focus distributions evaluated at other $z=\mathrm{const}$ planes. Three-dimensional molecular orbital distributions could thus be reconstructed directly from two-dimensional photoemission data, provided the axial resolution of the imaging system is high enough.
- Published
- 2018
- Full Text
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46. Intraoperative Navigation
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Rainer Schmelzeisen, Marc Christian Metzger, and Gido Bittermann
- Subjects
medicine.medical_specialty ,business.industry ,medicine ,Intraoperative navigation ,Radiology ,business - Published
- 2018
- Full Text
- View/download PDF
47. Common Blunders in Corporate Crises: How to Weatherthe Perfect Storm Practically
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Harry Gray, Chad Greenway, and Christian Metzger
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Finance ,Economics and Econometrics ,Battle ,Restructuring ,business.industry ,media_common.quotation_subject ,Cash ,Capital (economics) ,Command and control ,Economics ,Grit ,Set (psychology) ,business ,media_common ,Reputation - Abstract
Crises come on strong, and history tells us that few middle market companies are prepared for stormy seas. So, before the onslaught of a crisis, how can investors and advisors help management with battle planning and advance staging for either a turnaround or restructuring? Successful hands-on execution, especially in a crisis, is both an art and a science. Establishing command and control in a crisis requires much more than unlocking and preserving cash; it requires a unique battle-hardened skill set not typically developed during the course of a regular management career. Most general managers do not operate in venues depleted of capital, talent, reputation, and morale and are incongruous with the grit and grind of running a distressed company. The authors review common blunders in corporate crises and present indispensable lessons gleaned from corporate trench combat.
- Published
- 2013
- Full Text
- View/download PDF
48. Distressed Acquisitions: Sometimes Boast AnUncanny Resemblance To Three-Card Monte … YouCan Lose The Moment You Decide ToEnter The Game!
- Author
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Harry Gray, Chad Greenway, Don Bibeault, and Christian Metzger
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Apprehension ,business.industry ,Strategy and Management ,SCOOP ,Control (management) ,Public relations ,Cost cutting ,Private equity ,Management of Technology and Innovation ,Jungle ,medicine ,Economics ,medicine.symptom ,Marketing ,business ,computer ,Uncanny ,Finance ,Caveat emptor ,computer.programming_language - Abstract
These days, many first-time distressed investors will rush to scoop up incredible opportunities without apprehension. It must be easy, they think. We?ll just buy low, operate our way through the upturn, and sell high. Plus, multiples will be higher at exit, and we can refinance when credit eases. Everything will go according to plan. After all, control investments in troubled companies just need a new management team and some cost cutting, right? Caveat emptor … there are many tripwires and pitfalls in the distressed investing jungle. In this article, we share some tidbits gathered along our journey as both corporate performance experts and distressed private equity professionals.
- Published
- 2013
- Full Text
- View/download PDF
49. Electron-Vibration Coupling in Molecular Materials: Assignment of Vibronic Modes from Photoelectron Momentum Mapping
- Author
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Christian Tusche, Friedrich Reinert, Martin Graus, Achim Schöll, Matthias Dauth, Stephan Kümmel, Manuel Grimm, Christian Metzger, and J. Kirschner
- Subjects
Physics ,General Physics and Astronomy ,02 engineering and technology ,021001 nanoscience & nanotechnology ,01 natural sciences ,Molecular physics ,Momentum ,Coupling (physics) ,Vibronic coupling ,Molecular vibration ,Excited state ,0103 physical sciences ,Physics::Atomic and Molecular Clusters ,Vibronic spectroscopy ,Molecular orbital ,Physics::Chemical Physics ,010306 general physics ,0210 nano-technology ,Excitation - Abstract
Electron-phonon coupling is one of the most fundamental effects in condensed matter physics. We here demonstrate that photoelectron momentum mapping can reveal and visualize the coupling between specific vibrational modes and electronic excitations. When imaging molecular orbitals with high energy resolution, the intensity patterns of photoelectrons of the vibronic sidebands of molecular states show characteristic changes due to the distortion of the molecular frame in the vibronically excited state. By comparison to simulations, an assignment of specific vibronic modes is possible, thus providing unique information on the coupling between electronic and vibronic excitation.
- Published
- 2016
- Full Text
- View/download PDF
50. MatrixMANDIBLE Preformed Reconstruction Plates—A Two-Year Two-Institution Experience in 71 Patients
- Author
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Marc Christian Metzger, Rainer Schmelzeisen, Michael Ehrenfeld, Ralf Gutwald, M. Ermer, Gerson Mast, Christoph Pautke, Carl-Peter Cornelius, Sven Otto, Florian Andreas Probst, and Sebastian Schiel
- Subjects
Adult ,Male ,medicine.medical_specialty ,Osteoradionecrosis ,Operative Time ,Treatment outcome ,Mandibular Neoplasms ,Surgical Flaps ,Postoperative Complications ,Bone plate ,medicine ,Humans ,Aged ,Bone Transplantation ,Osteosynthesis ,business.industry ,Mandible ,Equipment Design ,Middle Aged ,medicine.disease ,Surgery ,Treatment Outcome ,Otorhinolaryngology ,Bone Substitutes ,Cohort ,Carcinoma, Squamous Cell ,Feasibility Studies ,Female ,Mandibular Reconstruction ,Oral Surgery ,Complication ,business ,Bone Plates - Abstract
Purpose To evaluate handling, complication rates, clinical and treatment outcomes of the MatrixMANDIBLE Preformed Reconstruction Plates (MMPRPs), in particular with regard to the frequency of fatigue fractures and operative time. Patients and Methods A cohort of 71 subjects with an indication for a load-bearing osteosynthesis of the mandible was enrolled in the present study. The indications for plate use were defects due to tumor, trauma, or osteonecrosis. The outcome variables were fitting accuracy, application time, and postoperative complications, defined as plate exposure, loosening of plates or screws, plate fracture, and orocutaneous fistulas. Additionally, the feasibility of a transoral approach was tested. Results The sample included 71 subjects with a mean age of 54.8 ± 15.0 years, including 43 men (60.6%). MMPRPs could be placed in 70 of the 71 patients. In 10 patients a transoral approach for plate application was successfully performed. The mean time investment to contour the plates was 13.1 minutes. The fitting accuracies of the nonbendable sections were satisfying. No plate fracture was observed within an average follow-up period of 11.8 months. Postoperative complications occurred in 19 (27.1%) of the 70 patients. Plate removal was required in 11 (15.7%) of 70 patients. Conclusions The results of the present study suggest that the use of MMPRPs coincides with a reduced operative time and a minimized risk of fatigue fractures. Thus, MMPRPs seem to be a useful standard device in a scope of indications for load-bearing osteosynthesis of the anterolateral division of the mandible, additionally facilitating a transoral approach for application.
- Published
- 2012
- Full Text
- View/download PDF
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