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282 results on '"Hesse, Bernhard"'

1. Microstructural investigation of hybrid CAD/CAM restorative dental materials by micro-CT and SEM

Author

Prause, Elisabeth, Hey, Jeremias, Beuer, Florian, Yassine, Jamila, Hesse, Bernhard, Weitkamp, Timm, Gerber, Javier, and Schmidt, Franziska

Subjects
Physics - Medical Physics, Condensed Matter - Materials Science, Physics - Applied Physics
Abstract

Objectives: An increasing number of CAD/CAM (computer-aided design/computer-aided manufacturing) hybrid materials have been introduced to the dental market in recent years. In addition, CAD/CAM hybrid materials for additive manufacturing (AM) are becoming more attractive in digital dentistry. Studies on material microstructures using micro-computed tomography ($\mu$-CT) combined with scanning electron microscopy (SEM) have only been available to a limited extent so far. Methods: One CAD/CAM three-dimensional- (3D-) printable hybrid material (VarseoSmile Crown plus) and two CAD/CAM millable hybrid materials (Vita Enamic; Voco Grandio), as well as one direct composite material (Ceram.x duo), were included in the present study. Cylindrical samples with a diameter of 2 mm were produced from each material and investigated by means of synchrotron radiation $\mu$-CT at a voxel size of 0.65 $\mu$m. Different samples from the same materials, obtained by cutting and polishing, were investigated by SEM. Results: The 3D-printed hybrid material showed some agglomerations and a more irregular distribution of fillers, as well as a visible layered macrostructure and a few spherical pores due to the printing process. The CAD/CAM millable hybrid materials revealed a more homogenous distribution of ceramic particles. The direct composite material showed multiple air bubbles and microstructural irregularities based on manual processing. Significance: The $\mu$-CT and SEM analysis of the materials revealed different microstructures even though they belong to the same class of materials. It could be shown that $\mu$-CT and SEM imaging are valuable tools to understand microstructure and related mechanical properties of materials., Comment: 24 pages, 4 tables, 12 figures including supplementary material

Published
2023
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12. Alterations of mass density and 3D osteocyte lacunar properties in bisphosphonate-related osteonecrotic human jaw bone, a synchrotron µCT study.

Author

Hesse, Bernhard, Langer, Max, Varga, Peter, Pacureanu, Alexandra, Dong, Pei, Schrof, Susanne, Männicke, Nils, Suhonen, Heikki, Olivier, Cecile, Maurer, Peter, Raum, Kay, Peyrin, Francoise, and Kazakia, Galateia

Subjects
Analysis of Variance, Bisphosphonate-Associated Osteonecrosis of the Jaw, Bone Density, Humans, Image Processing, Computer-Assisted, Osteocytes, Synchrotrons, X-Ray Microtomography
Abstract

Osteonecrosis of the jaw, in association with bisphosphonates (BRONJ) used for treating osteoporosis or cancer, is a severe and most often irreversible side effect whose underlying pathophysiological mechanisms remain largely unknown. Osteocytes are involved in bone remodeling and mineralization where they orchestrate the delicate equilibrium between osteoclast and osteoblast activity and through the active process called osteocytic osteolysis. Here, we hypothesized that (i) changes of the mineralized tissue matrix play a substantial role in the pathogenesis of BRONJ, and (ii) the osteocyte lacunar morphology is altered in BRONJ. Synchrotron µCT with phase contrast is an appropriate tool for assessing both the 3D morphology of the osteocyte lacunae and the bone matrix mass density. Here, we used this technique to investigate the mass density distribution and 3D osteocyte lacunar properties at the sub-micrometer scale in human bone samples from the jaw, femur and tibia. First, we compared healthy human jaw bone to human tibia and femur in order to assess the specific differences and address potential explanations of why the jaw bone is exclusively targeted by the necrosis as a side effect of BP treatment. Second, we investigated the differences between BRONJ and control jaw bone samples to detect potential differences which could aid an improved understanding of the course of BRONJ. We found that the apparent mass density of jaw bone was significantly smaller compared to that of tibia, consistent with a higher bone turnover in the jaw bone. The variance of the lacunar volume distribution was significantly different depending on the anatomical site. The comparison between BRONJ and control jaw specimens revealed no significant increase in mineralization after BP. We found a significant decrease in osteocyte-lacunar density in the BRONJ group compared to the control jaw. Interestingly, the osteocyte-lacunar volume distribution was not altered after BP treatment.

Published
2014

14. Comparison of the 3D-microstructure of human alveolar and fibula bone in microvascular autologous bone transplantation: a synchrotron radiation μ-CT study

Author

Wüster, Jonas, primary, Hesse, Bernhard, additional, Rothweiler, Rene, additional, Bortel, Emely, additional, Gross, Christian, additional, Bakhtiyari, Shima, additional, King, Andrew, additional, Boller, Elodie, additional, Gerber, Javier, additional, Rendenbach, Carsten, additional, Fretwurst, Tobias, additional, Preissner, Saskia, additional, Heiland, Max, additional, Nelson, Katja, additional, and Nahles, Susanne, additional

Published
2023
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17. A comparison of deep learning segmentation models for synchrotron radiation based tomograms of biodegradable bone implants.

Author

Marinho, André Lopes, Kazimi, Bashir, Cwieka, Hanna, Marek, Romy, Beckmann, Felix, Willumeit-Römer, Regine, Moosmann, Julian, Zeller-Plumhoff, Berit, Hesse, Bernhard, and Massimi, Lorenzo

Subjects
DEEP learning, BIOABSORBABLE implants, SYNCHROTRON radiation, CONVOLUTIONAL neural networks, DETERIORATION of materials, IMAGE segmentation
Abstract

Introduction: Synchrotron radiation micro-computed tomography (SRμCT) has been used as a non-invasive technique to examine the microstructure and tissue integration of biodegradable bone implants. To be able to characterize parameters regarding the disintegration and osseointegration of such materials quantitatively, the three-dimensional (3D) image data provided by SRμCT needs to be processed by means of semantic segmentation. However, accurate image segmentation is challenging using traditional automated techniques. This study investigates the effectiveness of deep learning approaches for semantic segmentation of SRμCT volumes of Mg-based implants in sheep bone ex vivo. Methodology: For this purpose different convolutional neural networks (CNNs), including U-Net, HR-Net, U[sup 2]-Net, from the TomoSeg framework, the Scaled U-Net framework, and 2D/3D U-Net from the nnU-Net framework were trained and validated. The image data used in this work was part of a previous study where biodegradable screws were surgically implanted in sheep tibiae and imaged using SRμCT after different healing periods. The comparative analysis of CNN models considers their performance in semantic segmentation and subsequent calculation of degradation and osseointegration parameters. The models' performance is evaluated using the intersection over union (loU) metric, and their generalization ability is tested on unseen datasets. Results and discussion: This work shows that the 2D nnU-Net achieves better generalization performance, with the degradation layer being the most challenging label to segment for all models. [ABSTRACT FROM AUTHOR]

Published
2024
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20. Increased Retention of Gadolinium in the Inflamed Brain After Repeated Administration of Gadopentetate Dimeglumine: A Proof-of-Concept Study in Mice Combining ICP-MS and Micro– and Nano–SR-XRF

Author

Wang, Shuangqing, Hesse, Bernhard, Roman, Marco, Stier, Deborah, Castillo-Michel, Hiram, Cotte, Marine, Suuronen, Jussi-Petteri, Lagrange, Adrien, Radbruch, Helena, Paul, Friedemann, Taupitz, Matthias, Schellenberger, Eyk, Sack, Ingolf, and Infante-Duarte, Carmen

Published
2019
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22. Examining iron complexes with organic ligands by laboratory XAFS

Author

Motz, Damian, primary, Praetz, Sebastian, additional, Schlesiger, Christopher, additional, Henniges, Jonathan, additional, Böttcher, Florian, additional, Hesse, Bernhard, additional, Castillo-Michel, Hiram, additional, Mijatz, Steven, additional, Malzer, Wolfgang, additional, Kanngießer, Birgit, additional, and Vogt, Carla, additional

Published
2023
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26. Deriving CoCrMo particle numbers and characteristics from synchrotron-based nano-analyses of human periprosthetic bone marrow

Author

Schoon, Janosch, Hesse, Bernhard, Geißler, Sven, Duda, Georg N., Perka, Carsten, Wassilew, Georgi, Perino, Giorgio, and Rakow, Anastasia

Subjects
microparticles, particle characterization, Medicine and health, arthroplasty, nanoparticles, chromium, cobalt, CoCrMo
Abstract

Objectives: Bone marrow (BM) is increasingly getting into focus in the course of investigating pathomechanisms of adverse effects related to periprosthetic inflammation induced by local exposure to particles released from arthroplasty implants. Particles released from cobalt-chromium-molybdenum (CoCrMo) [for full text, please go to the a.m. URL]

Published
2022
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27. Analytical and toxicological aspects of nanomaterials in different product groups: Challenges and opportunities

Author

Tschiche, Harald R., primary, Bierkandt, Frank S., additional, Creutzenberg, Otto, additional, Fessard, Valerie, additional, Franz, Roland, additional, Greiner, Ralf, additional, Gruber-Traub, Carmen, additional, Haas, Karl-Heinz, additional, Haase, Andrea, additional, Hartwig, Andrea, additional, Hesse, Bernhard, additional, Hund-Rinke, Kerstin, additional, Iden, Pauline, additional, Kromer, Charlotte, additional, Loeschner, Katrin, additional, Mutz, Diana, additional, Rakow, Anastasia, additional, Rasmussen, Kirsten, additional, Rauscher, Hubert, additional, Richter, Hannes, additional, Schoon, Janosch, additional, Schmid, Otmar, additional, Som, Claudia, additional, Spindler, Lena M., additional, Tovar, Günter E.M., additional, Westerhoff, Paul, additional, Wohlleben, Wendel, additional, Luch, Andreas, additional, and Laux, Peter, additional

Published
2022
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31. Comparison of the 3D-Microstructure Between Alveolar and Iliac Bone for Enhanced Bioinspired Bone Graft Substitutes

Author

Rothweiler, Rene, primary, Gross, Christian, additional, Bortel, Emely, additional, Früh, Sarah, additional, Gerber, Javier, additional, Boller, Elodie, additional, Wüster, Jonas, additional, Stricker, Andres, additional, Fretwurst, Tobias, additional, Iglhaut, Gerhard, additional, Nahles, Susanne, additional, Schmelzeisen, Rainer, additional, Hesse, Bernhard, additional, and Nelson, Katja, additional

Published
2022
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32. Biodegradation of a Magnesium Alloy Fixation Screw Used in a Guided Bone Regeneration Model in Beagle Dogs

Author

Rider, Patrick, primary, Kačarević, Željka Perić, additional, Elad, Akiva, additional, Rothamel, Daniel, additional, Sauer, Gerrit, additional, Bornert, Fabien, additional, Windisch, Peter, additional, Hangyási, Dávid, additional, Molnar, Balint, additional, Hesse, Bernhard, additional, Assad, Michel, additional, and Witte, Frank, additional

Published
2022
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35. Analytical and toxicological aspects of nanomaterials in different product groups:Challenges and opportunities

Author

Tschiche, Harald R., Bierkandt, Frank S., Creutzenberg, Otto, Fessard, Valerie, Franz, Roland, Greiner, Ralf, Gruber-Traub, Carmen, Haas, Karl-Heinz, Haase, Andrea, Hartwig, Andrea, Hesse, Bernhard, Hund-Rinke, Kerstin, Iden, Pauline, Kromer, Charlotte, Loeschner, Katrin, Mutz, Diana, Rakow, Anastasia, Rasmussen, Kirsten, Rauscher, Hubert, Richter, Hannes, Schoon, Janosch, Schmid, Otmar, Som, Claudia, Spindler, Lena M., Tovar, Günter E. M., Westerhoff, Paul, Wohlleben, Wendel, Luch, Andreas, Laux, Peter, Tschiche, Harald R., Bierkandt, Frank S., Creutzenberg, Otto, Fessard, Valerie, Franz, Roland, Greiner, Ralf, Gruber-Traub, Carmen, Haas, Karl-Heinz, Haase, Andrea, Hartwig, Andrea, Hesse, Bernhard, Hund-Rinke, Kerstin, Iden, Pauline, Kromer, Charlotte, Loeschner, Katrin, Mutz, Diana, Rakow, Anastasia, Rasmussen, Kirsten, Rauscher, Hubert, Richter, Hannes, Schoon, Janosch, Schmid, Otmar, Som, Claudia, Spindler, Lena M., Tovar, Günter E. M., Westerhoff, Paul, Wohlleben, Wendel, Luch, Andreas, and Laux, Peter

Abstract

The widespread integration of engineered nanomaterials into consumer and industrial products creates new challenges and requires innovative approaches in terms of design, testing, reliability, and safety of nanotechnology. The aim of this review article is to give an overview of different product groups in which nanomaterials are present and outline their safety aspects for consumers. Here, release of nanomaterials and related analytical challenges and solutions as well as toxicological considerations, such as dose-metrics, are discussed. Additionally, the utilization of engineered nanomaterials as pharmaceuticals or nutraceuticals to deliver and release cargo molecules is covered. Furthermore, critical pathways for human exposure to nanomaterials, namely inhalation and ingestion, are discussed in the context of risk assessment. Analysis of NMs in food, innovative medicine or food contact materials is discussed. Specific focus is on the presence and release of nanomaterials, including whether nanomaterials can migrate from polymer nanocomposites used in food contact materials. With regard to the toxicology and toxicokinetics of nanomaterials, aspects of dose metrics of inhalation toxicity as well as ingestion toxicology and comparison between in vitro and in vivo conclusions are considered. The definition of dose descriptors to be applied in toxicological testing is emphasized. In relation to potential exposure from different products, opportunities arising from the use of advanced analytical techniques in more unique scenarios such as release of nanomaterials from medical devices such as orthopedic implants are addressed. Alongside higher product performance and complexity, further challenges regarding material characterization and safety, as well as acceptance by the general public are expected.

Published
2022

38. Analysis of a Pure Magnesium Membrane Degradation Process and Its Functionality When Used in a Guided Bone Regeneration Model in Beagle Dogs

Author

Rider, Patrick, primary, Kačarević, Željka Perić, additional, Elad, Akiva, additional, Rothamel, Daniel, additional, Sauer, Gerrit, additional, Bornert, Fabien, additional, Windisch, Peter, additional, Hangyási, Dávid, additional, Molnar, Balint, additional, Hesse, Bernhard, additional, and Witte, Frank, additional

Published
2022
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41. Interconnectivity Explains High Canalicular Network Robustness between Neighboring Osteocyte Lacunae in Human Bone

Author

Bortel, Emely, primary, Grover, Liam M, additional, Eisenstein, Neil, additional, Seim, Christian, additional, Suhonen, Heikki, additional, Pacureanu, Alexandra, additional, Westenberger, Peter, additional, Raum, Kay, additional, Langer, Max, additional, Peyrin, Francoise, additional, Addison, Owen, additional, and Hesse, Bernhard, additional

Published
2021
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45. Metal-Specific Biomaterial Accumulation in Human Peri-Implant Bone and Bone Marrow

Author

Schoon, Janosch, Hesse, Bernhard, Rakow, Anastasia, Ort, Melanie J., Lagrange, Adrien, Jacobi, Dorit, Winter, Annika, Huesker, Katrin, Reinke, Simon, Cotte, Marine, Tucoulou, Remi, Marx, Uwe, Perka, Carsten, Duda, Georg N., and Geissler, Sven

Subjects
bone marrow, Full Paper, synchrotron radiation, arthroplasty, lcsh:Q, nanoparticles, Full Papers, 600 Technik, Technologie, lcsh:Science, ddc:600, 600 Technik, Medizin, angewandte Wissenschaften::610 Medizin und Gesundheit::610 Medizin und Gesundheit, metal exposure
Abstract

Metallic implants are frequently used in medicine to support and replace degenerated tissues. Implant loosening due to particle exposure remains a major cause for revision arthroplasty. The exact role of metal debris in sterile peri‐implant inflammation is controversial, as it remains unclear whether and how metals chemically alter and potentially accumulate behind an insulating peri‐implant membrane, in the adjacent bone and bone marrow (BM). An intensively focused and bright synchrotron X‐ray beam allows for spatially resolving the multi‐elemental composition of peri‐implant tissues from patients undergoing revision surgery. In peri‐implant BM, particulate cobalt (Co) is exclusively co‐localized with chromium (Cr), non‐particulate Cr accumulates in the BM matrix. Particles consisting of Co and Cr contain less Co than bulk alloy, which indicates a pronounced dissolution capacity. Particulate titanium (Ti) is abundant in the BM and analyzed Ti nanoparticles predominantly consist of titanium dioxide in the anatase crystal phase. Co and Cr but not Ti integrate into peri‐implant bone trabeculae. The characteristic of Cr to accumulate in the intertrabecular matrix and trabecular bone is reproducible in a human 3D in vitro model. This study illustrates the importance of updating the view on long‐term consequences of biomaterial usage and reveals toxicokinetics within highly sensitive organs., Spatially micron‐ and nanoresolved synchrotron X‐ray fluorescence analyses of peri‐implant cancellous bone reveal specific distribution and accumulation patterns of metals released from alloys frequently used in knee and hip arthroplasty. These new insights of the local toxicokinetics of metallic debris prove that cobalt, chromium, and titanium exposure also occurs behind the insulating implant membrane, in the bone and bone marrow.

Published
2020

47. The elimination of caffein: an experimental study on herbivora and carnivora

Author

United States. Bureau of Chemistry, Hesse, Bernhard Conrad, 1869, Salant, William, U.S. Department of Agriculture, National Agricultural Library, University of California Libraries (archive.org), United States. Bureau of Chemistry, Hesse, Bernhard Conrad, 1869, and Salant, William

Subjects
Carnivora, Herbivores
Published
1912

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