Finite Element Simulation of Opening Angle Response of Porcine Aortas Using Layer Specific GAG Distributions in One and Two Layered Solid Matrices
Bibliographic record
Abstract
PURPOSE: Recent studies have identified an effect of glycosaminoglycans (GAG) on residual stresses in the aorta, underscoring the need to better understand their biomechanical roles. METHODS: Aortic ring models for each of the ascending, arch and descending thoracic regions of the porcine thoracic aorta were created in FEBioStudio, using a framework that incorporates the Donnan osmotic swelling in a porous solid matrix. The distribution of fixed charge densities (FCD) through the thickness of the tissue was prescribed as calculated from experimentally quantified sulfated GAG mural distributions. Material parameters for the solid matrix, modeled using a Holmes-Mow constitutive law, were optimized using data from biaxial tensile tests. In addition to modelling the solid matrix as one layer, two layers were considered to capture the differences between the intima-media and the adventitia, for which various stiffness ratios were explored. RESULTS: As the stiffness of the adventitia with respect to that of the media increased, the simulated opening angle increased. The opening angle also decreased from the ascending to the descending thoracic region in both one- and two-layered solid matrices models. The simulated results were compared against the experimental contribution of GAG to the opening angle, as previously quantified via enzymatic GAG-depletion. When using one layer for the solid matrix, the errors between the simulated opening angles and the experimental contribution of GAG to the opening angle were respectively 28%, 15% and 23% in the ascending, arch and descending thoracic regions. When using two layers for the solid matrix, the smallest errors in the ascending and arch regions were 21% and 5% when the intima-media was modelled as 10 times stiffer, and as twice stiffer than the adventitia, respectively, and 23% in the descending thoracic regions when the intima-media and adventitia shared similar mechanical properties. CONCLUSIONS: Overall, this study demonstrates that GAG partially contribute to circumferential residual stress, and that GAG swelling is one of several regulators of the opening angle. The minor discrepancies between simulated and experimental opening angles imply that the contribution of GAG extends beyond mere swelling, aligning with previous experimental indications of their interaction with ECM fibers in determining the opening angle.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".