{ "types" : { "Bookmark" : { "pluralLabel" : "Bookmarks" }, "Publication" : { "pluralLabel" : "Publications" }, "GoldStandardPublication" : { "pluralLabel" : "GoldStandardPublications" }, "GoldStandardBookmark" : { "pluralLabel" : "GoldStandardBookmarks" }, "Tag" : { "pluralLabel" : "Tags" }, "User" : { "pluralLabel" : "Users" }, "Group" : { "pluralLabel" : "Groups" }, "Sphere" : { "pluralLabel" : "Spheres" } }, "properties" : { "count" : { "valueType" : "number" }, "date" : { "valueType" : "date" }, "changeDate" : { "valueType" : "date" }, "url" : { "valueType" : "url" }, "id" : { "valueType" : "url" }, "tags" : { "valueType" : "item" }, "user" : { "valueType" : "item" } }, "items" : [ { "type" : "Publication", "id" : "https://puma.ub.uni-stuttgart.de/bibtex/2eeb7eec4365e95de248e73401073785a/inspo5", "tags" : [ "Biaxial","Biological","Stress-strain-relationship","mechanics","stomach","tissue","Inspo","testing","tensile","soft","Porcine","Organ" ], "intraHash" : "eeb7eec4365e95de248e73401073785a", "interHash" : "252446e0dc715c88dc9bb6f9988761ec", "label" : "Regional differences in stomach stretch during organ filling and their implications on the mechanical stress response", "user" : "inspo5", "description" : "", "date" : "2024-04-30 15:05:35", "changeDate" : "2024-04-30 15:05:35", "count" : 2, "pub-type": "article", "journal": "Journal of Biomechanics","publisher":"Elsevier BV", "year": "2024", "url": "http://dx.doi.org/10.1016/j.jbiomech.2024.112107", "author": [ "Stefan Papenkort","Mischa Borsdorf","Simon Kiem","Markus Böl","Tobias Siebert" ], "authors": [ {"first" : "Stefan", "last" : "Papenkort"}, {"first" : "Mischa", "last" : "Borsdorf"}, {"first" : "Simon", "last" : "Kiem"}, {"first" : "Markus", "last" : "Böl"}, {"first" : "Tobias", "last" : "Siebert"} ], "editor": [ "Tobias Siebert" ], "editors": [ {"first" : "Tobias", "last" : "Siebert"} ], "volume": "168","pages": "112107","abstract": "As part of the digestive system, the stomach plays a crucial role in the health and well-being of an organism. It produces acids and performs contractions that initiate the digestive process and begin the break-up of ingested food. Therefore, its mechanical properties are of interest. This study includes a detailed investigation of strains in the porcine stomach wall during passive organ filling. In addition, the observed strains were applied to tissue samples subjected to biaxial tensile tests. The results show inhomogeneous strains during filling, which tend to be higher in the circumferential direction (antrum: 13.2%, corpus: 22.0%, fundus: 67.8%), compared to the longitudinal direction (antrum: 4.8%, corpus: 24.7%, fundus: 50.0%) at a maximum filling of 3500 ml. Consequently, the fundus region experienced the greatest strain. In the biaxial tensile experiments, the corpus region appeared to be the stiffest, reaching nominal stress values above 400 kPa in the circumferential direction, whereas the other regions only reached stress levels of below 50 kPa in both directions for the investigated stretch range. Our findings gain new insight into stomach mechanics and provide valuable data for the development and validation of computational stomach models.", "language" : "English", "issn" : "0021-9290", "doi" : "10.1016/j.jbiomech.2024.112107", "bibtexKey": "Papenkort_2024" } , { "type" : "Publication", "id" : "https://puma.ub.uni-stuttgart.de/bibtex/28f5714b08b370985753e1ad4303910d0/inspo5", "tags" : [ "Stomach","organ","modeling","inhomogeneity","asymmetry","wall","FE-Simulation" ], "intraHash" : "8f5714b08b370985753e1ad4303910d0", "interHash" : "76575d1fa103a0c642129b7df609a72c", "label" : "A geometry model of the porcine stomach featuring mucosa and muscle layer thicknesses", "user" : "inspo5", "description" : "", "date" : "2023-04-27 07:36:09", "changeDate" : "2023-04-27 07:36:09", "count" : 3, "pub-type": "article", "journal": "Journal of the Mechnical Behavior of Biomedical Materials", "year": "2023", "url": "https://www.sciencedirect.com/science/article/pii/S1751616123001546?via%3Dihub#kwrds0010", "author": [ "Stefan Papenkort","Mischa Borsdorf","Markus Böl","Tobias Siebert" ], "authors": [ {"first" : "Stefan", "last" : "Papenkort"}, {"first" : "Mischa", "last" : "Borsdorf"}, {"first" : "Markus", "last" : "Böl"}, {"first" : "Tobias", "last" : "Siebert"} ], "volume": "142","number": "105801","abstract": "Abstract\r\nThe stomach is a vital organ responsible for food storage, digestion, and transport. Stomach diseases are of great economic and medical importance and require a large number of bariatric surgeries every year. To improve medical interventions, in silico modeling of the gastrointestinal tract has gained popularity in recent years to study stomach functioning. Because of the great structural and nutritional similarity between the porcine and human stomach, the porcine stomach is a suitable surrogate for the development and validation of gastric models. This study presents a realistic 3D geometry model of the porcine stomach based on a photogrammetric reconstruction of a real organ. Layer thicknesses of the stomach wall's mucosa and tunica muscularis were determined by more than 1900 manual measurements at different locations. Layer thickness distributions show mean mucosal and muscle thicknesses of 2.29 ± 0.45 mm and 2.83 ± 0.99 mm, respectively. In general, layer thicknesses increase from fundus (mucosa: 1.82 ± 0.19 mm, muscle layer: 2.59 ± 0.32 mm) to antrum (mucosa: 2.69 ± 0.31 mm, muscle layer: 3.73 ± 1.05 mm). The analysis of stomach asymmetry with respect to an idealized symmetrical stomach model, an approach often used in the literature, revealed volumetric deviations of 45%, 15%, and 92% for the antrum, corpus, and fundus, respectively. The present work also suggests an algorithm for the computation of longitudinal and circumferential directions at local points. These directions are useful for the implementation of material anisotropy. In addition, we present data on the passive pressure-volume relationship of the organ and perform an exemplary finite-element simulation, where we demonstrate the applicability of the model. We encourage others to utilize the geometry model featuring profound asymmetry for future model-based investigations on stomach functioning.", "identifier" : "tobias.siebert@inspo.uni-stuttgart.de", "language" : "English", "doi" : "https://doi.org/10.1016/j.jmbbm.2023.105801", "bibtexKey": "noauthororeditor" } , { "type" : "Publication", "id" : "https://puma.ub.uni-stuttgart.de/bibtex/2f3d78410850201349b3420cb0f71115a/inspo5", "tags" : [ "Stomach","Uniaxial","Force","experiments","velocity","length","layer","relationship","muscle","Contractile","Separated","tensile","wall","Organ","properties" ], "intraHash" : "f3d78410850201349b3420cb0f71115a", "interHash" : "b79cfd3a81cd8360cba0a6d4729f7452", "label" : "Influence of layer separation on the determination of stomach smooth muscle properties.", "user" : "inspo5", "description" : "", "date" : "2022-07-19 11:10:29", "changeDate" : "2022-07-19 09:10:56", "count" : 2, "pub-type": "article", "journal": "Pflugers Arch", "year": "2021", "url": "https://link.springer.com/article/10.1007/s00424-021-02568-5", "author": [ "Mischa Borsdorf","Markus Böl","Tobias Siebert" ], "authors": [ {"first" : "Mischa", "last" : "Borsdorf"}, {"first" : "Markus", "last" : "Böl"}, {"first" : "Tobias", "last" : "Siebert"} ], "editor": [ "Tobias Siebert" ], "editors": [ {"first" : "Tobias", "last" : "Siebert"} ], "volume": "473","pages": "911-920","abstract": "Uniaxial tensile experiments are a standard method to determine the contractile properties of smooth muscles. Smooth muscle strips from organs of the urogenital and gastrointestinal tract contain multiple muscle layers with different muscle fiber orientations, which are frequently not separated for the experiments. During strip activation, these muscle fibers contract in deviant orientations from the force-measuring axis, affecting the biomechanical characteristics of the tissue strips. This study aimed to investigate the influence of muscle layer separation on the determination of smooth muscle properties. Smooth muscle strips, consisting of longitudinal and circumferential muscle layers (whole-muscle strips [WMS]), and smooth muscle strips, consisting of only the circumferential muscle layer (separated layer strips [SLS]), have been prepared from the fundus of the porcine stomach. Strips were mounted with muscle fibers of the circumferential layer inline with the force-measuring axis of the uniaxial testing setup. The force\u2013length (FLR) and force\u2013velocity relationships (FVR) were determined through a series of isometric and isotonic contractions, respectively. Muscle layer separation revealed no changes in the FLR. However, the SLS exhibited a higher maximal shortening velocity and a lower curvature factor than WMS. During WMS activation, the transversally oriented muscle fibers of the longitudinal layer shortened, resulting in a narrowing of this layer. Expecting volume constancy of muscle tissue, this narrowing leads to a lengthening of the longitudinal layer, which counteracted the shortening of the circumferential layer during isotonic contractions. Consequently, the shortening velocities of the WMS were decreased significantly. This effect was stronger at high shortening velocities.", "language" : "English", "doi" : "doi:10.1007/s00424-021-02568-5", "bibtexKey": "borsdorf2021influence" } , { "type" : "Publication", "id" : "https://puma.ub.uni-stuttgart.de/bibtex/2346fb7cde84b5e8f820d71aa9d8e0ce0/inspo5", "tags" : [ "Stomach","tension","Biaxial","staining","Tissue","composition","muscle","testingTissue","Smooth","Microstructure","wall" ], "intraHash" : "346fb7cde84b5e8f820d71aa9d8e0ce0", "interHash" : "2f5fd279259cd2399f3e049e26399fc7", "label" : "Biomechanical and microstructural characterisation of the porcine stomach wall: Location- and layer-dependent investigations", "user" : "inspo5", "description" : "", "date" : "2022-07-19 11:10:29", "changeDate" : "2022-07-19 09:10:56", "count" : 2, "pub-type": "article", "journal": "Acta Biomaterialia","publisher":"Elsevier BV", "year": "2020", "url": "https://doi.org/10.1016%2Fj.actbio.2019.11.038", "author": [ "Melanie Bauer","Enrique Morales-Orcajo","Lisa Klemm","Robert Seydewitz","Victoria Fiebach","Tobias Siebert","Markus Böl" ], "authors": [ {"first" : "Melanie", "last" : "Bauer"}, {"first" : "Enrique", "last" : "Morales-Orcajo"}, {"first" : "Lisa", "last" : "Klemm"}, {"first" : "Robert", "last" : "Seydewitz"}, {"first" : "Victoria", "last" : "Fiebach"}, {"first" : "Tobias", "last" : "Siebert"}, {"first" : "Markus", "last" : "Böl"} ], "editor": [ "Tobias Siebert" ], "editors": [ {"first" : "Tobias", "last" : "Siebert"} ], "volume": "102","pages": "83--99", "doi" : "10.1016/j.actbio.2019.11.038", "bibtexKey": "Bauer_2020" } ] }