Tear propagation in vaginal tissue under inflation

McGuire, Jeffrey A.; Monclova, Jose L.; Coariti, Adriana C. Salazar; Stine, Caleb A.; Toussaint, Kimani C.; Munson, Jennifer M.; Dillard, David A.

doi:10.1016/j.actbio.2021.03.065

Cited by 12 publications

(9 citation statements)

References 41 publications

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“…Together with a realistic geometry, boundary and loading conditions, a new constitutive law that accounts for the experimentally measured statistical distributions of collagen fibers 32 and smooth muscle fibers 44 should be developed for the rat vagina. The specific form of the Holzapfel‐Gasser‐Ogden constitutive model used in this study does not consider the exact distributions of such fibers in the rat vagina.…”

Section: Discussionmentioning

confidence: 99%

“…The geometry, boundary conditions, and material parameters used to construct the FE model that describes the deformations of rat vaginal specimens subjected to luminal pressure were selected to approximate experimental data 31,32 . During the experiments, the vaginal tissue was mounted onto dispensing needles and inflated via a pressure pump with phosphate buffered saline.…”

Section: Full Order Modelmentioning

confidence: 99%

“…The mean preferred fiber directions,

{bold-italica}_{italic1} = (0, \cos β, \sin β)

and

{bold-italica}_{italic2} = (0, \cos β, - \sin β)

, and fiber dispersion parameter, κ , were chosen to be representative of the collagen fiber organization that was measured experimentally in the tangential (or hoop‐axial) plane of the vagina (Figure 9 in reference 32). The angle β was defined relative to the hoop direction of the vagina, that is the hoop direction was at a 0 ° angle.…”

Section: Full Order Modelmentioning

confidence: 99%

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Data‐driven variational multiscale reduced order modeling of vaginal tissue inflation

Snyder

McGuire

Mou

et al. 2022

Numer Methods Biomed Eng

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The vagina undergoes large finite deformations and has complex geometry and microstructure, resulting in material and geometric nonlinearities, complicated boundary conditions, and nonhomogeneities within finite element (FE) simulations. These nonlinearities pose a significant challenge for numerical solvers, increasing the computational time by several orders of magnitude.Simplifying assumptions can reduce the computational time significantly, but this usually comes at the expense of simulation accuracy. This study proposed the use of reduced order modeling (ROM) techniques to capture experimentally measured displacement fields of rat vaginal tissue during inflation testing in order to attain both the accuracy of higher-fidelity models and the speed of simpler simulations. The proper orthogonal decomposition (POD) method was used to extract the significant information from FE simulations generated by varying the luminal pressure and the parameters that introduce the anisotropy in the selected constitutive model. A new data-driven (DD) variational multiscale (VMS) ROM framework was extended to obtain the displacement fields of rat vaginal tissue under pressure. For comparison purposes, we also investigated the classical Galerkin ROM (G-ROM). In our numerical study, both the G-ROM and the DD-VMS-ROM decreased the FE computational cost by orders of magnitude without a significant decrease in numerical accuracy. Furthermore, the DD-VMS-ROM improved the G-ROM accuracy at a modest computational overhead. Our numerical investigation showed that ROM has the potential to provide efficient and accurate computational tools to describe vaginal deformations, with the ultimate goal of improving maternal health.

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Section: Discussionmentioning

confidence: 99%

Section: Full Order Modelmentioning

confidence: 99%

“…The mean preferred fiber directions,

{bold-italica}_{italic1} = (0, \cos β, \sin β)

and

{bold-italica}_{italic2} = (0, \cos β, - \sin β)

Section: Full Order Modelmentioning

confidence: 99%

See 1 more Smart Citation

Data‐driven variational multiscale reduced order modeling of vaginal tissue inflation

Snyder

McGuire

Mou

et al. 2022

Numer Methods Biomed Eng

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“…All samples were imaged using a commercial multiphoton microscope using an excitation wavelength at or near 780 nm; examples with experimental details can be found in our previous papers (see Refs. 6 , 7 , and 16 ). For all porcine and rat samples, at least three representative SHG images are selected for subsequent analysis.…”

Section: Methodsmentioning

confidence: 99%

“…1 , 2 The organization of collagenous fibers could be used as a biomarker for structural anomalies, disease diagnosis and progression, aging, tissue development, and damage. 1 , 3 – 7 The noncentrosymmetric molecular assembly of fibrillar collagen produces a nonlinear optical response when it interacts with light where two input photons produce an output photon with twice the frequency, a process known as second-harmonic generation (SHG). 8 Therefore, high contrast images of collagenous fibers without exogenous staining can be obtained through SHG microscopy.…”

Section: Introductionmentioning

confidence: 99%

Fluid mechanics approach to analyzing collagen fiber organization

et al. 2022

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. Significance: The spatial organization of collagen fibers has been used as a biomarker for assessing injury and disease progression. However, quantifying this organization for complex structures is challenging. Aim: To quantify and classify complex collagen fiber organizations. Approach: Using quantitative second-harmonic generation (SHG) microscopy, we show that collagen-fiber orientation can be viewed as pseudovector fields. Subsequently, we analyze them using fluid mechanic metrics, such as energy , enstrophy , and tortuosity . Results: We show that metrics used in fluid mechanics for analyzing fluid flow can be adapted to analyze complex collagen fiber organization. As examples, we consider SHG images of collagenous tissue for straight, wavy, and circular fiber structures. Conclusions: The results of this study show the utility of the chosen metrics to distinguish diverse and complex collagen organizations. We find that the distribution of values for and increases with collagen fiber disorganization, where they divide between low and high values corresponding to uniformly aligned fibers and disorganized collagen fibers, respectively. We also confirm that the values of cluster around 1 when the fibers are straight, and the range increases up to 1.5 when wavier fibers are present.

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