Swine Vagina Under Planar Biaxial Loads: An Investigation of Large Deformations and Tears

2019 ◽  
Vol 141 (4) ◽  
Author(s):  
Jeffrey A. McGuire ◽  
Steven D. Abramowitch ◽  
Spandan Maiti ◽  
Raffaella De Vita
Keyword(s):  
Biaxial Loading ◽  
Video Recording ◽  
Experimental Studies ◽  
Longitudinal Direction ◽  
Image Correlation ◽  
Vaginal Tissue ◽  
Highly Nonlinear ◽  
Biaxial Tests ◽  
Function Relationship ◽  
Relationship Of

Vaginal tears are very common and can lead to severe complications such as hemorrhaging, fecal incontinence, urinary incontinence, and dyspareunia. Despite the implications of vaginal tears on women's health, there are currently no experimental studies on the tear behavior of vaginal tissue. In this study, planar equi-biaxial tests on square specimens of vaginal tissue, with sides oriented along the longitudinal direction (LD) and circumferential direction (CD), were conducted using swine as animal model. Three groups of specimens were mechanically tested: the NT group (n = 9), which had no pre-imposed tear, the longitudinal tear (LT) group (n = 9), and the circumferential tear (CT) group (n = 9), which had central pre-imposed elliptically shaped tears with major axes oriented in the LD and the CD, respectively. Through video recording during testing, axial strains were measured for the NT group using the digital image correlation (DIC) technique and axial displacements of hook clamps were measured for the NT, LT, and CT groups in the LD and CD. The swine vaginal tissue was found to be highly nonlinear and somewhat anisotropic. Up to normalized axial hook displacements of 1.15, no tears were observed to propagate, suggesting that the vagina has a high resistance to further tearing once a tear has occurred. However, in response to biaxial loading, the size of the tears for the CT group increased significantly more than the size of the tears for the LT group (p = 0.003). The microstructural organization of the vagina is likely the culprit for its tear resistance and orientation-dependent tear behavior. Further knowledge on the structure–function relationship of the vagina is needed to guide the development of new methods for preventing the severe complications of tearing.

scholarly journals Strength characterization of glass/epoxy plain weave composite under different biaxial loading ratios

2020 ◽  
Vol 54 (19) ◽  
pp. 2549-2563
Author(s):  
A Kobeissi ◽  
P Rahme ◽  
L Leotoing ◽  
D Guines
Keyword(s):  
Biaxial Loading ◽  
Central Zone ◽  
Correlation Method ◽  
Axial Loading ◽  
Failure Criteria ◽  
Image Correlation ◽  
Biaxial Test ◽  
Cruciform Specimen ◽  
Plain Weave ◽  
Biaxial Tests

Over the past years, various studies have been investigated in order to characterize the behavior of composite materials under different multi-axial loading conditions. One of the most used biaxial techniques is the in-plane biaxial test on cruciform specimens. To achieve reliable biaxial failure results, the design of the cruciform specimen presents a crucial part. Previous studies show that there is no well-adapted cruciform geometry for the composite biaxial tests. In this paper, an optimal cruciform specimen has been defined numerically for the composite characterization test. The specimen is composed of two aluminum tabs glued on top and bottom side of the plain-weave glass/epoxy composite. Finite element simulations have been carried out in order to study the influence of the aluminum grade and thickness on the stress distribution in the composite. An experimental validation confirms the failure of the specimen in the central zone under three different biaxial tensile ratios. The experimental strains were evaluated using the digital image correlation method. The traction/traction quadrant of the failure envelop was obtained and compared with different failure criteria. The maximum strain criterion shows a good agreement with the experimental results.

scholarly journals Parameter Estimation and Application of Anisotropic Yield Criteria for Cylindrical Aluminum Extrusions: Theoretical Developments and StereoDIC Measurements

2021 ◽  
Vol 11 (20) ◽  
pp. 9701
Author(s):  
Farzana Yasmeen ◽  
Michael A. Sutton ◽  
Xiaomin Deng ◽  
Megan Ryan ◽  
Anthony P. Reynolds
Keyword(s):  
Plastic Anisotropy ◽  
Experimental Studies ◽  
Longitudinal Direction ◽  
Theoretical Models ◽  
Yield Function ◽  
Shear Loading ◽  
Image Correlation ◽  
Yield Model ◽  
Yield Criteria ◽  
Shear Strains

Theoretical and experimental studies are presented to characterize the anisotropic plastic response under torsion loading of two nominally identical aluminum Al6061-T6 extruded round bars. Theoretical models are developed using isotropic (Von Mises 1913) and anisotropic (Barlat 1991) yield criteria, along with isotropic strain hardening formulae, to model post-yield behavior under simple torsion loading. For the case of simple shear loading, incremental plasticity theory is used to determine the theoretical elastic, plastic, and total shear strains. A set of experiments are performed to calibrate Barlat’s 1991 yield function. Several specimens are extracted at different orientations to the longitudinal direction of each round Al6061-T6 bar and tested under uniaxial tension and simple torsion to optimally determine all anisotropic (Barlat 1991) yield function parameters. During loading, Stereo Digital Image Correlation (DIC) is used to quantify surface deformations for the torsion experiments and a baseline tension specimen to identify and correct measurement anomalies. Results show the isotropic yield model either underestimates or overestimates the experimental shear strains for both extrusions. Conversely, results using the Barlat 1991 anisotropic yield criteria are in excellent agreement with experimental measurements for both extrusions. The presence of significant differences in the anisotropic parameters for nominally similar extrusions confirms that plastic anisotropy is essential for the accurate prediction of mechanical behavior in longitudinally extruded Al6061-T6 bars.

scholarly journals Bayesian statistics show a lack of change in excitability following bihemispheric HD-TDCS over the primary somatosensory cortices

2019 ◽  
Author(s):  
Gallo Selene ◽  
Thijs J. Baaijen ◽  
Suttrup Judith ◽  
Fernandes-Henriques Carolina ◽  
Keysers Christian ◽  
...  
Keyword(s):  
Somatosensory Cortex ◽  
Effect Size ◽  
Causal Structure ◽  
Experimental Studies ◽  
Time Data ◽  
High Definition ◽  
Median Nerve Stimulation ◽  
Somatosensory Cortices ◽  
Function Relationship ◽  
Relationship Of

ABSTRACTBackgroundHigh Definition transcranial Direct Current Stimulation (HD-tDCS) is a method meant to explore the causal structure-function relationship of brain areas, developed to improve the spatial resolution of tDCS, but the validity of tDCS results is currently under intense debateObjectiveThe goal of this study is to validate a new HD-tDCS protocol for bilateral modulation of the Somatosensory Cortex (SI). The new montage is meant to increase the focus of the stimulation while limiting the area of the scalp covered by electrodes. We aim to characterize the effect of the stimulation in terms of directionality, consistency and reproducibility.MethodsWe aim to leverage a 1 × 1 montage to most focally stimulate the primary somatosensory cortex (SI) and measure modulation via Somatosensory Evoked Potentials (SEP) triggered by median nerve stimulation.ResultsThe results of Experiment1 suggest that our montage increases the amplitude of the SEP component N30. In Experiment2, we aim to replicate our finding and to assess the duration of the modulatory effect on N30 over time. Data from Experiment2 fails to replicate N30 modulation. A sequential Bayesian analysis performed on N30 data from both experiments indicates that the effect fluctuates across participants, without a clear homogenous directionality.ConclusionThis study sets boundaries on the effect size that can be expected for this montage and illustrates the need to include replication samples or larger sample sizes to avoid overestimating effect sizes. We conclude that our montage has insufficient effect size for use in moderately sample-sized experimental studies and clinical applications.

Monosaccharide Biosynthesis Pathways Database

Glycobiology ◽  
2021 ◽  
Author(s):  
Jaya Srivastava ◽  
P Sunthar ◽  
Petety V Balaji
Keyword(s):  
Expression Profiling ◽  
Experimental Studies ◽  
Structural Complexity ◽  
Evolutionary Relationships ◽  
Enzyme Assays ◽  
Biosynthesis Pathway ◽  
Knock Out ◽  
Set Up ◽  
Function Relationship ◽  
Natural Glycans

Abstract A distinctive feature of glycans vis-à-vis proteins and nucleic acids is its structural complexity which arises from the huge repertoire of monosaccharides, isomeric linkages and branching. A very large number of monosaccharides have so far been discovered in natural glycans. Experimentally, pathways for the biosynthesis have been characterized completely for 55 monosaccharides and partially for a few more. However, there is no single platform which provides information about monosaccharide biosynthesis pathways and associated enzymes We have gathered 572 experimentally characterized enzymes of 66 biosynthesis pathways from literature and set up a first of its kind database called the Monosaccharide Biosynthesis Pathways Database http://www.bio.iitb.ac.in/mbpd/). Annotations such as the reaction catalysed, substrate specificity, biosynthesis pathway and PubMed IDs are provided for all the enzymes in the database. Sequence homologs of the experimentally characterized enzymes found in nearly 13,000 completely sequenced genomes from Bacteria and Archaea have also been included in the database. This platform will help in the deduction of evolutionary relationships among enzymes such as aminotransferases, nucleotidyltransferases, acetyltransferases and SDR family enzymes. It can also facilitate experimental studies such as direct enzyme assays to validate putative annotations, establish structure–function relationship, expression profiling to determine the function, determine the phenotypic consequences of gene knock-out/knock-in and complementation studies.

Structure–property–function relationship of fluorescent conjugated microporous polymers

2021 ◽  
Author(s):  
M. G. Monika Bai ◽  
H. Vignesh Babu ◽  
V. Lakshmi ◽  
M. Rajeswara Rao
Keyword(s):  
Long Range ◽  
Structure Property ◽  
Porous Organic Polymers ◽  
Aggregation Induced Emission ◽  
Microporous Polymers ◽  
Exciton Migration ◽  
Wide Range ◽  
Function Relationship ◽  
Relationship Of ◽  
Conjugated Microporous Polymers

Fluorescent porous organic polymers are a unique class of materials owing to their strong aggregation induced emission, long range exciton migration and permanent porosity, thus envisioned to possess a wide range of applications (sensing, OLEDs).

Morphology-Function Relationship of Thermoelectric Nanocomposite Films from PEDOT:PSS with Silicon Nanoparticles

2017 ◽  
Vol 3 (8) ◽  
pp. 1700181 ◽  
Author(s):  
Nitin Saxena ◽  
Mihael Čorić ◽  
Anton Greppmair ◽  
Jan Wernecke ◽  
Mika Pflüger ◽  
...  
Keyword(s):  
Silicon Nanoparticles ◽  
Nanocomposite Films ◽  
Function Relationship ◽  
Relationship Of

scholarly journals High-resolution single-cell 3D-models of chromatin ensembles during Drosophila embryogenesis

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Qiu Sun ◽  
Alan Perez-Rathke ◽  
Daniel M. Czajkowsky ◽  
Zhifeng Shao ◽  
Jie Liang
Keyword(s):  
High Resolution ◽  
Single Cell ◽  
3D Models ◽  
Computational Method ◽  
Midblastula Transition ◽  
Genome Wide ◽  
Large Ensembles ◽  
Chromatin Folding ◽  
Function Relationship ◽  
Relationship Of

AbstractSingle-cell chromatin studies provide insights into how chromatin structure relates to functions of individual cells. However, balancing high-resolution and genome wide-coverage remains challenging. We describe a computational method for the reconstruction of large 3D-ensembles of single-cell (sc) chromatin conformations from population Hi-C that we apply to study embryogenesis in Drosophila. With minimal assumptions of physical properties and without adjustable parameters, our method generates large ensembles of chromatin conformations via deep-sampling. Our method identifies specific interactions, which constitute 5–6% of Hi-C frequencies, but surprisingly are sufficient to drive chromatin folding, giving rise to the observed Hi-C patterns. Modeled sc-chromatins quantify chromatin heterogeneity, revealing significant changes during embryogenesis. Furthermore, >50% of modeled sc-chromatin maintain topologically associating domains (TADs) in early embryos, when no population TADs are perceptible. Domain boundaries become fixated during development, with strong preference at binding-sites of insulator-complexes upon the midblastula transition. Overall, high-resolution 3D-ensembles of sc-chromatin conformations enable further in-depth interpretation of population Hi-C, improving understanding of the structure-function relationship of genome organization.

Role of aromatic residues in the structure-function relationship of .alpha.-bungarotoxin

Biochemistry ◽  
1982 ◽  
Vol 21 (11) ◽  
pp. 2592-2600 ◽  
Author(s):  
Yee Hsiung Chen ◽  
Jang Chyi Tai ◽  
Wan Jen Huang ◽  
Ming Zong Lai ◽  
Mien Chie Hung ◽  
...  
Keyword(s):  
Structure Function ◽  
Aromatic Residues ◽  
Structure Function Relationship ◽  
Function Relationship ◽  
Alpha Bungarotoxin ◽  
Relationship Of
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