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Ex vivo experimental investigations and modelling of the layer-dependent, anisotropic, visco-hyperelastic behaviour of the human oesophagus / Ciara Durcan

Swansea University Author: Ciara Durcan

DOI (Published version): 10.23889/SUthesis.66103

Abstract

As a mechanical organ, the material properties of the oesophagus are integral to its function. The quantification of these properties is necessary to investigate the organ’s pathophysiology and is required for a range of applications including medical device design, surgical simula-tions and tissue...

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Published: Swansea, Wales, UK 2024
Institution: Swansea University
Degree level: Doctoral
Degree name: Ph.D
Supervisor: Hossain, Mokarram ; Perić, Djordje
URI: https://cronfa.swan.ac.uk/Record/cronfa66103
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spelling v2 66103 2024-04-20 Ex vivo experimental investigations and modelling of the layer-dependent, anisotropic, visco-hyperelastic behaviour of the human oesophagus 7ecf37dea19f79476ca596fa79d01454 Ciara Durcan Ciara Durcan true false 2024-04-20 FGSEN As a mechanical organ, the material properties of the oesophagus are integral to its function. The quantification of these properties is necessary to investigate the organ’s pathophysiology and is required for a range of applications including medical device design, surgical simula-tions and tissue engineering. However, according to a systematic review of mechanical exper-imentation conducted on the gastrointestinal organs, the discrete layer-dependent properties of the oesophagus have not been investigated using human tissue, especially regarding its vis-coelastic and stress-softening behaviour. Therefore, extensive experimentation was conducted to determine the time, layer and direction-dependent material response of the oesophagus us-ing cadaveric human tissue. The residual strains of the organ were also considered via opening angle experiments. Overall, the results showed distinct properties in each layer, highlighting the importance of treating the oesophagus as a multi-layered composite material. Furthermore, a strong anisotropy was exhibited across both layers, where the longitudinal directions were much stiffer than the circumferential directions. Due to the COVID-19 pandemic, fresh human cadavers were not available from the anatomy laboratory for a considerable amount of time. Therefore, mechanical testing was first completed on embalmed human tissue and then, once available, on fresh human tissue. This unforeseen circumstance, through comparison of the two preservation states, allowed for an interesting discussion on the role of the tissue’s con-stituents on its complex material behaviour. In addition, histological analysis was carried out to determine the density of the oesophagus’ most mechanically relevant fibres: collagen and elastin. This knowledge was then used to inform constitutive modelling of the soft tissue’s behaviour, the outcome of which was able to capture the anisotropy, visco-hyperelasticity and stress-softening observed in the experimental data. E-Thesis Swansea, Wales, UK Biomechanics, Soft tissues, Gastrointestinal tract, Constitutive modelling, Cadaver preservation 21 2 2024 2024-02-21 10.23889/SUthesis.66103 COLLEGE NANME Science and Engineering - Faculty COLLEGE CODE FGSEN Swansea University Hossain, Mokarram ; Perić, Djordje Doctoral Ph.D Swansea University Strategic Partnerships Research Scholarships (SUSPRS) 2024-04-20T14:18:36.0389624 2024-04-20T13:46:50.7829442 Faculty of Science and Engineering School of Aerospace, Civil, Electrical, General and Mechanical Engineering - Mechanical Engineering Ciara Durcan 1 66103__30089__1acf6ee8e74d4342b9f1a43fbc45c327.pdf Durcan_Ciara_B_PhD_Thesis_Final_Redacted_Signature.pdf 2024-04-20T14:09:32.7593806 Output 96084662 application/pdf E-Thesis – open access true Copyright: The Author, Ciara B. Durcan, 2024. true eng
title Ex vivo experimental investigations and modelling of the layer-dependent, anisotropic, visco-hyperelastic behaviour of the human oesophagus
spellingShingle Ex vivo experimental investigations and modelling of the layer-dependent, anisotropic, visco-hyperelastic behaviour of the human oesophagus
Ciara Durcan
title_short Ex vivo experimental investigations and modelling of the layer-dependent, anisotropic, visco-hyperelastic behaviour of the human oesophagus
title_full Ex vivo experimental investigations and modelling of the layer-dependent, anisotropic, visco-hyperelastic behaviour of the human oesophagus
title_fullStr Ex vivo experimental investigations and modelling of the layer-dependent, anisotropic, visco-hyperelastic behaviour of the human oesophagus
title_full_unstemmed Ex vivo experimental investigations and modelling of the layer-dependent, anisotropic, visco-hyperelastic behaviour of the human oesophagus
title_sort Ex vivo experimental investigations and modelling of the layer-dependent, anisotropic, visco-hyperelastic behaviour of the human oesophagus
author_id_str_mv 7ecf37dea19f79476ca596fa79d01454
author_id_fullname_str_mv 7ecf37dea19f79476ca596fa79d01454_***_Ciara Durcan
author Ciara Durcan
author2 Ciara Durcan
format E-Thesis
publishDate 2024
institution Swansea University
doi_str_mv 10.23889/SUthesis.66103
college_str Faculty of Science and Engineering
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hierarchy_top_id facultyofscienceandengineering
hierarchy_top_title Faculty of Science and Engineering
hierarchy_parent_id facultyofscienceandengineering
hierarchy_parent_title Faculty of Science and Engineering
department_str School of Aerospace, Civil, Electrical, General and Mechanical Engineering - Mechanical Engineering{{{_:::_}}}Faculty of Science and Engineering{{{_:::_}}}School of Aerospace, Civil, Electrical, General and Mechanical Engineering - Mechanical Engineering
document_store_str 1
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description As a mechanical organ, the material properties of the oesophagus are integral to its function. The quantification of these properties is necessary to investigate the organ’s pathophysiology and is required for a range of applications including medical device design, surgical simula-tions and tissue engineering. However, according to a systematic review of mechanical exper-imentation conducted on the gastrointestinal organs, the discrete layer-dependent properties of the oesophagus have not been investigated using human tissue, especially regarding its vis-coelastic and stress-softening behaviour. Therefore, extensive experimentation was conducted to determine the time, layer and direction-dependent material response of the oesophagus us-ing cadaveric human tissue. The residual strains of the organ were also considered via opening angle experiments. Overall, the results showed distinct properties in each layer, highlighting the importance of treating the oesophagus as a multi-layered composite material. Furthermore, a strong anisotropy was exhibited across both layers, where the longitudinal directions were much stiffer than the circumferential directions. Due to the COVID-19 pandemic, fresh human cadavers were not available from the anatomy laboratory for a considerable amount of time. Therefore, mechanical testing was first completed on embalmed human tissue and then, once available, on fresh human tissue. This unforeseen circumstance, through comparison of the two preservation states, allowed for an interesting discussion on the role of the tissue’s con-stituents on its complex material behaviour. In addition, histological analysis was carried out to determine the density of the oesophagus’ most mechanically relevant fibres: collagen and elastin. This knowledge was then used to inform constitutive modelling of the soft tissue’s behaviour, the outcome of which was able to capture the anisotropy, visco-hyperelasticity and stress-softening observed in the experimental data.
published_date 2024-02-21T14:18:32Z
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score 11.037253

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