scholarly journals An inverse method for mechanical characterization of heterogeneous diseased arteries using intravascular imaging

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Bharath Narayanan ◽  
Max L. Olender ◽  
David Marlevi ◽  
Elazer R. Edelman ◽  
Farhad R. Nezami
Keyword(s):  
In Silico ◽  
Mechanical Characterization ◽  
Imaging Data ◽  
New Approach ◽  
Parameter Recovery ◽  
Material Parameters ◽  
Linear Elastic ◽  
Novel Method

AbstractThe increasing prevalence of finite element (FE) simulations in the study of atherosclerosis has spawned numerous inverse FE methods for the mechanical characterization of diseased tissue in vivo. Current approaches are however limited to either homogenized or simplified material representations. This paper presents a novel method to account for tissue heterogeneity and material nonlinearity in the recovery of constitutive behavior using imaging data acquired at differing intravascular pressures by incorporating interfaces between various intra-plaque tissue types into the objective function definition. Method verification was performed in silico by recovering assigned material parameters from a pair of vessel geometries: one derived from coronary optical coherence tomography (OCT); one generated from in silico-based simulation. In repeated tests, the method consistently recovered 4 linear elastic (0.1 ± 0.1% error) and 8 nonlinear hyperelastic (3.3 ± 3.0% error) material parameters. Method robustness was also highlighted in noise sensitivity analysis, where linear elastic parameters were recovered with average errors of 1.3 ± 1.6% and 8.3 ± 10.5%, at 5% and 20% noise, respectively. Reproducibility was substantiated through the recovery of 9 material parameters in two more models, with mean errors of 3.0 ± 4.7%. The results highlight the potential of this new approach, enabling high-fidelity material parameter recovery for use in complex cardiovascular computational studies.

About Puncture Testing Applied for Mechanical Characterization of Fetal Membranes

2014 ◽  
Vol 136 (11) ◽  
Author(s):  
Wilfried Bürzle ◽  
Edoardo Mazza ◽  
John J. Moore
Keyword(s):  
Deformation Behavior ◽  
Mechanical Characterization ◽  
Ex Vivo ◽  
Fetal Membrane ◽  
Membrane Rupture ◽  
Resistance To Deformation ◽  
Ex Vivo Testing ◽  
Insight Into

Puncture testing has been applied in several studies for the mechanical characterization of human fetal membrane (FM) tissue, and significant knowledge has been gained from these investigations. When comparing results of mechanical testing (puncture, inflation, and uniaxial tension), we have observed discrepancies in the rupture sequence of FM tissue and significant differences in the deformation behavior. This study was undertaken to clarify these discrepancies. Puncture experiments on FM samples were performed to reproduce previous findings, and numerical simulations were carried out to rationalize particular aspects of membrane failure. The results demonstrate that both rupture sequence and resistance to deformation depend on the samples' fixation. Soft fixation leads to slippage in the clamping, which reduces mechanical loading of the amnion layer and results in chorion rupturing first. Conversely, the stiffer, stronger, and less extensible amnion layer fails first if tight fixation is used. The results provide a novel insight into the interpretation of ex vivo testing as well as in vivo membrane rupture.

scholarly journals In vivo measurement of intrauterine pressure by telemetry: a new approach for studying parturition in mouse models

2010 ◽  
Vol 42 (2) ◽  
pp. 310-316 ◽  
Author(s):  
Stephanie L. Pierce ◽  
William Kutschke ◽  
Rafael Cabeza ◽  
Sarah K. England
Keyword(s):  
Mouse Models ◽  
Accurate Method ◽  
Isometric Tension ◽  
Mouse Uterus ◽  
New Approach ◽  
In Vivo Measurement ◽  
Intrauterine Pressure

Transgenic and knockout mouse models have proven useful in the study of genes necessary for parturition—including genes that affect the timing and/or progression of labor contractions. However, taking full advantage of these models will require a detailed characterization of the contractile patterns in the mouse uterus. Currently the best methodology for this has been measurement of isometric tension in isolated muscle strips in vitro. However, this methodology does not provide a real-time measure of changes in uterine pressure over the course of pregnancy. Recent advances have opened the possibility of using radiotelemetric devices to more accurately and comprehensively study intrauterine pressure in vivo. We tested the effectiveness of this technology in the mouse, in both wild-type (WT) mice and a mouse model of defective parturition (SK3 channel-overexpressing mice), after surgical implant of telemetry transmitters into the uterine horn. Continuous recordings from day 18 of pregnancy through delivery revealed that WT mice typically deliver during the 12-h dark cycle after 19.5 days postcoitum. In these mice, intrauterine pressure gradually increases during this cycle, to threefold greater than that measured during the 12-h cycle before delivery. SK3-overexpressing mice, by contrast, exhibited lower intrauterine pressure over the same period. These results are consistent with the outcome of previous in vitro studies, and they indicate that telemetry is an accurate method for measuring uterine contraction, and hence parturition, in mice. The use of this technology will lead to important novel insights into changes in intrauterine pressure during the course of pregnancy.

Tissue Elasticity Estimation with Optical Coherence Elastography: Toward Mechanical Characterization of In Vivo Soft Tissue

2005 ◽  
Vol 33 (11) ◽  
pp. 1631-1639 ◽  
Author(s):  
Ahmad S. Khalil ◽  
Raymond C. Chan ◽  
Alexandra H. Chau ◽  
Brett E. Bouma ◽  
Mohammad R. Kaazempur Mofrad
Keyword(s):  
Soft Tissue ◽  
Mechanical Characterization ◽  
Optical Coherence ◽  
Tissue Elasticity

scholarly journals Characterization of the virome of Paracoccus spp. (Alphaproteobacteria) by combined in silico and in vivo approaches

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Przemyslaw Decewicz ◽  
Lukasz Dziewit ◽  
Piotr Golec ◽  
Patrycja Kozlowska ◽  
Dariusz Bartosik ◽  
...  
Keyword(s):  
In Silico

Mechanical, Electrical and Thermal Characterization of Commercially Available LTCC Dielectric Tapes

2013 ◽  
Vol 543 ◽  
pp. 212-215
Author(s):  
Goran Radosavljević ◽  
Nelu Blaž ◽  
Andrea Marić ◽  
W. Smetana ◽  
Ljiljana Živanov
Keyword(s):  
Mechanical Properties ◽  
Surface Roughness ◽  
Electrical Properties ◽  
Material Characterization ◽  
Mechanical Characterization ◽  
Thermal Characterization ◽  
Material Parameters ◽  
Mechanical And Electrical Properties

Presented paper deals with mechanical and electrical properties of several commercially available LTCC (Low Temperature Co-fired Technology) tapes, as well as their thermal characterization. Three commercially available dielectric tape materials provided by Heraeus (CT700, CT707 and CT800) are investigated. The samples for determination of significant material parameters are prepared using the standard LTCC fabrication process. Results of the material characterization (chemical analysis, surface roughness electrical and mechanical properties) are presented. In addition thermo-electrical and-mechanical characterization of investigated tapes analysis is performed.

In-silico structural, functional and immunogenic characterization of Taenia solium TS14 protein

2017 ◽  
Author(s):  
Chitra Joshi ◽  
Siddharth Gautam
Keyword(s):  
Amino Acid ◽  
In Silico ◽  
Mutational Analysis ◽  
Solvent Accessibility ◽  
Taenia Solium ◽  
Secretory Protein ◽  
Single Amino Acid

TS14, a Cysticercosis cellulosae derived protein, has been exploited for immunodiagnosis of cysticercosis in humans and pigs. However, the information on structure, function, stability and immunogenicity of TS14 derived from different isolates is primarily lacking. The present study deals with in-silico characterization of six TS14 isolates. High thermostability and an isoelectric point of 9.41 were recorded. Based on N-terminal amino acid residues, high resistance to intracellular proteases with extended in-vivo and in-vitro half-lives was predicted. TS14 is foreseen as a secretory protein with a signal peptide and an extracellular localization. Structural analysis of TS14 exhibited the dominance of helices in the secondary structure (92% coverage) with majority of residues showing high and medium solvent accessibility. High lysine content and presence of multiple nucleotide binding sites in TS14 suggests interaction with RNA/DNA and a role in their metabolism. Immunogenic profiling predicted presence of four distinct B-cell epitopes. Mutational analysis based on the single amino acid substitutions among six TS14 isolates demonstrated minor variations in structural stability; however, all the substitutions were well tolerated. Moreover, all the isolates revealed almost identical immunogenic profile with an equivocal potential to elicit the antibody-mediated immune response.

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