scholarly journals A Biomechanical Study of Directional Mechanical Properties of Porcine Skin Tissues

2013 ◽  
Author(s):  
Hsiao-Ying Shadow Huang ◽  
Siyao Huang ◽  
Taylor Gettys ◽  
Peter M. Prim ◽  
Ola L. Harrysson
Keyword(s):  
Material Properties ◽  
Biomechanical Properties ◽  
Biomechanical Study ◽  
Skin Tissue ◽  
Elastic Fibers ◽  
Fiber Direction ◽  
Porcine Skin ◽  
Biomechanical Behavior ◽  
Skin Stretching ◽  
Material Stiffness

Skin is a multilayered composite material and composed principally of the proteins collagen, elastic fibers, and fibroblasts. The direction-dependent material properties of skin tissue is important for physiological functions like skin expansion. The current study has developed methods to characterize the directional biomechanical properties of porcine skin tissues. It is observed that skin tissue has a nonlinear anisotropy biomechanical behavior, where the parameters of material stiffness is 378 ±160 kPa in the preferred-fiber direction and 65.96±40.49 kPa in the cross-fiber direction when stretching above 30% strain equibiaxially. The results from the current study will help optimize functional skin stretching for patients requiring large surface area skin grafts and reconstructions due to burns or other injuries.

DIRECTIONAL BIOMECHANICAL PROPERTIES OF PORCINE SKIN TISSUE

2014 ◽  
Vol 14 (05) ◽  
pp. 1450069 ◽  
Author(s):  
HSIAO-YING SHADOW HUANG ◽  
SIYAO HUANG ◽  
COLIN P. FRAZIER ◽  
PETER M. PRIM ◽  
OLA HARRYSSON
Keyword(s):  
Material Properties ◽  
Collagen Fiber ◽  
Biomechanical Properties ◽  
Skin Tissue ◽  
Elastic Fibers ◽  
Fiber Direction ◽  
Porcine Skin ◽  
Biomechanical Behavior ◽  
Tissue Anisotropy ◽  
Biaxial Mechanical Properties

Skin is a multilayered composite material and composed principally of the proteins collagen, elastic fibers and fibroblasts. The direction-dependent material properties of skin tissue is important for physiological functions like skin expansion. The current study has developed methods to characterize the directional biomechanical properties of porcine skin tissues as studies have shown that pigs represent a useful animal model due to similarities between porcine and human skin. It is observed that skin tissue has a nonlinear anisotropy biomechanical behavior, where the parameters of material modulus is 378 ± 160 kPa in the preferred-fiber direction and 65.96 ± 40.49 kPa in the cross-fiber direction when stretching above 30% strain equibiaxially. The result from the study provides methods of characterizing biaxial mechanical properties of skin tissue, as the collagen fiber direction appears to be one of the primary determinants of tissue anisotropy.

Die unterschiedliche Ausdehnung der Übergangszone in der Karotisgabel

VASA ◽  
2001 ◽  
Vol 30 (2) ◽  
pp. 101-106 ◽  
Author(s):  
J. Janzen ◽  
P. Lanzer ◽  
K. Rothenberger-Janzen ◽  
P.N. Vuong
Keyword(s):  
Carotid Artery ◽  
Transitional Zone ◽  
Biomechanical Properties ◽  
Elastic Fibers ◽  
Arterial Segment ◽  
Biomechanical Behavior ◽  
Atherosclerotic Lesions ◽  
The Media ◽  
Potential Factor ◽  
The Impact

Background: The goal of our study was to demonstrate the extension of the transitional zone (TZ) between elastic and muscular medial structure in carotid artery tripod. Patients and methods: A histologic study of 56 probes from 8 carotid artery tripods was performed. The probes were obtained from autopsies of 4 adults (mean age: 47.5 years, range 38 to 55 years) and were taken from 7 different topographic sites. Results: At each level of the CCA (at 1 cm and 2 cm proximal to the bifurcation as well as at the bifurcation) we observed an elastic arterial type in 24 (42.8%) probes with 11 to 20 (medium 15.0) elastic fibers per view field (200 ¥ magnification) in the media. In contrast the histologic structure of the ICA and ECA varied as follows: in 8 sections (14.3%) elastic arterial type with 11 to 16 (medium 13.1) elastic fibers, in 11 sections (19.6%) muscular arterial type with 2 to 5 (medium 3.5) elastic fibers and in 9 sections (16.1%) a transitional arterial type with 6 to 8 (medium 6.7) elastic fibers in the media. Atherosclerotic lesions have prevented the assessment of the arterial type in 4 probes (7.1%). The TZ in the medial structure of carotid artery tripods is exclusively localized in the ICA/ECA but not in the CCA. The ICA/ECA presented a TZ with a length up to 0.5 cm (4 probes; 25%), up to 1.5 cm (4 probes; 25%) and longer than 1.5 cm (6 probes; 37.5%). Conclusions: In this study we confirmed that in the carotid artery tripod, a TZ – an arterial segment with transition from elastic to muscular type – does exist, involving a variable length. Furthermore studies on the impact of the biomechanical properties of the TZ as a potential factor in atherosclerotic disease are justified. In addition, the complex biomechanical behavior of the TZ should be considered prior to interventional procedures.

scholarly journals Pigmentation Affects Elastic Fiber Patterning and Biomechanical Behavior of the Murine Aortic Valve

2021 ◽  
Vol 8 ◽  
Author(s):  
Sana Nasim ◽  
Popular Pandey ◽  
Rosemeire M. Kanashiro-Takeuchi ◽  
Jin He ◽  
Joshua D. Hutcheson ◽  
...  
Keyword(s):  
Aortic Valve ◽  
Elastic Fiber ◽  
Biomechanical Properties ◽  
Systemic Circulation ◽  
Elastic Fibers ◽  
Multiphoton Imaging ◽  
Force Microscopy ◽  
Biomechanical Behavior ◽  
Atomic Force ◽  
Fiber Organization

The aortic valve (AoV) maintains unidirectional blood distribution from the left ventricle of the heart to the aorta for systemic circulation. The AoV leaflets rely on a precise extracellular matrix microarchitecture of collagen, elastin, and proteoglycans for appropriate biomechanical performance. We have previously demonstrated a relationship between the presence of pigment in the mouse AoV with elastic fiber patterning using multiphoton imaging. Here, we extended those findings using wholemount confocal microscopy revealing that elastic fibers were diminished in the AoV of hypopigmented mice (KitWv and albino) and were disorganized in the AoV of K5-Edn3 transgenic hyperpigmented mice when compared to wild type C57BL/6J mice. We further used atomic force microscopy to measure stiffness differences in the wholemount AoV leaflets of mice with different levels of pigmentation. We show that AoV leaflets of K5-Edn3 had overall higher stiffness (4.42 ± 0.35 kPa) when compared to those from KitWv (2.22 ± 0.21 kPa), albino (2.45 ± 0.16 kPa), and C57BL/6J (3.0 ± 0.16 kPa) mice. Despite the striking elastic fiber phenotype and noted stiffness differences, adult mutant mice were found to have no overt cardiac differences as measured by echocardiography. Our results indicate that pigmentation, but not melanocytes, is required for proper elastic fiber organization in the mouse AoV and dictates its biomechanical properties.

Optimization of a decellularization protocol of porcine tracheas. Long-term effects of cryopreservation. A histological study

2021 ◽  
pp. 039139882110089
Author(s):  
Lara Milian ◽  
María Sancho-Tello ◽  
Joan Roig-Soriano ◽  
Giovanna Foschini ◽  
Néstor J Martínez-Hernández ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Histological Study ◽  
Biomechanical Properties ◽  
Elastic Fibers ◽  
Appreciable Effect ◽  
Long Term Effects ◽  
Minimal Impact ◽  
Biomechanical Effect ◽  
Triton X

Objective: The aim of this study was to optimize a decellularization protocol in the trachea of Sus scrofa domestica (pig) as well as to study the effects of long-term cryopreservation on the extracellular matrix of decellularized tracheas. Methods: Porcine tracheas were decellularized using Triton X-100, SDC, and SDS alone or in combination. The effect of these detergents on the extracellular matrix characteristics of decellularized porcine tracheas was evaluated at the histological, biomechanical, and biocompatibility level. Morphometric approaches were used to estimate the effect of detergents on the collagen and elastic fibers content as well as on the removal of chondrocytes from decellularized organs. Moreover, the long-term structural, ultrastructural, and biomechanical effect of cryopreservation of decellularized tracheas were also estimated. Results: Two percent SDS was the most effective detergent tested concerning cell removal and preservation of the histological and biomechanical properties of the tracheal wall. However, long-term cryopreservation had no an appreciable effect on the structure, ultrastructure, and biomechanics of decellularized tracheal rings. Conclusion: The results presented here reinforce the use of SDS as a valuable decellularizing agent for porcine tracheas. Furthermore, a cryogenic preservation protocol is described, which has minimal impact on the histological and biomechanical properties of decellularized porcine tracheas.

A COMPARATIVE BIOMECHANICAL STUDY OF THE LOOPED SQUARE SLIP KNOT AND THE SIMPLE SURGICAL KNOT

Hand Surgery ◽  
2006 ◽  
Vol 11 (01n02) ◽  
pp. 93-99 ◽  
Author(s):  
Surut Jianmongkol ◽  
Geoffrey Hooper ◽  
Weerachai Kowsuwon ◽  
Tala Thammaroj
Keyword(s):  
Ultimate Strength ◽  
Hand Surgery ◽  
Biomechanical Properties ◽  
Biomechanical Study ◽  
Skin Closure ◽  
Significant Difference ◽  
Mode Of Failure ◽  
Repetitive Loading ◽  
Slip Knot

The looped square slip knot was introduced as a technique for skin closure to avoid the use of sharp instruments in suture removal after hand surgery. We compared the biomechanical properties of this knot with the simple surgical square knot. The ultimate strength of the looped square slip knot was significantly (p = 0.015) higher than the simple surgical knot. There was no significant difference between the two knots in mode of failure. Knot slippage or suture breakage did not occur in any samples when testing security by repetitive loading. Therefore, the looped square slip knot is a safe and convenient alternative to the two-throw surgical knot for use in hand surgery.

scholarly journals Material properties and effect of preconditioning of human sclera, optic nerve, and optic nerve sheath

2021 ◽  
Author(s):  
Joseph Park ◽  
Andrew Shin ◽  
Somaye Jafari ◽  
Joseph L. Demer
Keyword(s):  
Optic Nerve ◽  
Mechanical Behavior ◽  
Material Properties ◽  
Biomechanical Properties ◽  
Ocular Tissues ◽  
Tangent Moduli ◽  
Nonlinear Mechanical ◽  
Human Eyes ◽  
Range Of Variation ◽  
Great Stress

AbstractThe optic nerve (ON) is a recently recognized tractional load on the eye during larger horizontal eye rotations. In order to understand the mechanical behavior of the eye during adduction, it is necessary to characterize material properties of the sclera, ON, and in particular its sheath. We performed tensile loading of specimens taken from fresh postmortem human eyes to characterize the range of variation in their biomechanical properties and determine the effect of preconditioning. We fitted reduced polynomial hyperelastic models to represent the nonlinear tensile behavior of the anterior, equatorial, posterior, and peripapillary sclera, as well as the ON and its sheath. For comparison, we analyzed tangent moduli in low and high strain regions to represent stiffness. Scleral stiffness generally decreased from anterior to posterior ocular regions. The ON had the lowest tangent modulus, but was surrounded by a much stiffer sheath. The low-strain hyperelastic behaviors of adjacent anatomical regions of the ON, ON sheath, and posterior sclera were similar as appropriate to avoid discontinuities at their boundaries. Regional stiffnesses within individual eyes were moderately correlated, implying that mechanical properties in one region of an eye do not reliably reflect properties of another region of that eye, and that potentially pathological combinations could occur in an eye if regional properties are discrepant. Preconditioning modestly stiffened ocular tissues, except peripapillary sclera that softened. The nonlinear mechanical behavior of posterior ocular tissues permits their stresses to match closely at low strains, although progressively increasing strain causes particularly great stress in the peripapillary region.

Abstract 562: Human Carotid Atherosclerosis Plaque Progression and Vessel Material Stiffness at Follow Up Had Positive Correlation: An in vivo Vessel Stiffness MRI Follow Up Study

2017 ◽  
Vol 37 (suppl_1) ◽  
Author(s):  
Qingyu Wang ◽  
Dalin Tang ◽  
Gador Canton ◽  
Jian Guo ◽  
Xiaoya Guo ◽  
...  
Keyword(s):  
Negative Correlation ◽  
Material Properties ◽  
Stretch Ratio ◽  
Patient Specific ◽  
Plaque Progression ◽  
Material Stiffness ◽  
Variation Rate ◽  
Vessel Material

It is hypothesized that artery stiffness may be associated with plaque progression. However, in vivo vessel material stiffness follow-up data is lacking in the literature. In vivo 3D multi-contrast and Cine magnetic resonance imaging (MRI) carotid plaque data were acquired from 8 patients with follow-up (18 months) with written informed consent obtained. Cine MRI and 3D thin-layer models were used to determine parameter values of the Mooney-Rivlin models for the 81slices from 16 plaques (2 scans/patient) using our established iterative procedures. Effective Young’s Modulus (YM) values for stretch ratio [1.0,1.3] were calculated for each slice for analysis. Stress-stretch ratio curves from Mooney-Rivlin models for the 16 plaques and 81 slices are given in Fig. 1. Average YM value of the 81 slices was 411kPa. Slice YM values varied from 70 kPa (softest) to 1284 kPa (stiffest), a 1734% difference. Average slice YM values by vessel varied from 109 kPa (softest) to 922 kPa (stiffest), a 746% difference. Location-wise, the maximum slice YM variation rate within a vessel was 306% (139 kPa vs. 564 kPa). Average slice YM variation rate within a vessel for the 16 vessels was 134%. Average variation of YM values from baseline (T1) to follow up (T2) for all patients was 61.0%. The range of the variation of YM values was [-28.4%, 215%]. For progression study, YM increase (YMI=YM T2 -TM T1 ) showed negative correlation with plaque progression measured by wall thickness increase (WTI), (r= -0.6802, p=0.0634). YM T2 showed strong negative correlation with WTI (r= -0.7764, p=0.0235). Correlation between YM T1 and WTI was not significant (r= -0.4353, p= 0.2811). Conclusion In vivo carotid vessel material properties have large variations from patient to patient, along the vessel segment within a patient, and from baseline to follow up. Use of patient-specific, location specific and time-specific material properties could potentially improve the accuracy of model stress/strain calculations.

scholarly journals Infarcted Left Ventricles Have Stiffer Material Properties and Lower Stiffness Variation: Three-Dimensional Echo-Based Modeling to Quantify In Vivo Ventricle Material Properties

2015 ◽  
Vol 137 (8) ◽  
Author(s):  
Longling Fan ◽  
Jing Yao ◽  
Chun Yang ◽  
Dalin Tang ◽  
Di Xu
Keyword(s):  
Wall Thickness ◽  
Material Properties ◽  
Strain Curve ◽  
Stress And Strain ◽  
Stress Strain ◽  
Material Stiffness ◽  
The Mean ◽  
Lv Volume ◽  
Parameter Values

Methods to quantify ventricle material properties noninvasively using in vivo data are of great important in clinical applications. An ultrasound echo-based computational modeling approach was proposed to quantify left ventricle (LV) material properties, curvature, and stress/strain conditions and find differences between normal LV and LV with infarct. Echo image data were acquired from five patients with myocardial infarction (I-Group) and five healthy volunteers as control (H-Group). Finite element models were constructed to obtain ventricle stress and strain conditions. Material stiffening and softening were used to model ventricle active contraction and relaxation. Systolic and diastolic material parameter values were obtained by adjusting the models to match echo volume data. Young's modulus (YM) value was obtained for each material stress–strain curve for easy comparison. LV wall thickness, circumferential and longitudinal curvatures (C- and L-curvature), material parameter values, and stress/strain values were recorded for analysis. Using the mean value of H-Group as the base value, at end-diastole, I-Group mean YM value for the fiber direction stress–strain curve was 54% stiffer than that of H-Group (136.24 kPa versus 88.68 kPa). At end-systole, the mean YM values from the two groups were similar (175.84 kPa versus 200.2 kPa). More interestingly, H-Group end-systole mean YM was 126% higher that its end-diastole value, while I-Group end-systole mean YM was only 29% higher that its end-diastole value. This indicated that H-Group had much greater systole–diastole material stiffness variations. At beginning-of-ejection (BE), LV ejection fraction (LVEF) showed positive correlation with C-curvature, stress, and strain, and negative correlation with LV volume, respectively. At beginning-of-filling (BF), LVEF showed positive correlation with C-curvature and strain, but negative correlation with stress and LV volume, respectively. Using averaged values of two groups at BE, I-Group stress, strain, and wall thickness were 32%, 29%, and 18% lower (thinner), respectively, compared to those of H-Group. L-curvature from I-Group was 61% higher than that from H-Group. Difference in C-curvature between the two groups was not statistically significant. Our results indicated that our modeling approach has the potential to determine in vivo ventricle material properties, which in turn could lead to methods to infer presence of infarct from LV contractibility and material stiffness variations. Quantitative differences in LV volume, curvatures, stress, strain, and wall thickness between the two groups were provided.

A novel testing system for biomechanical evaluation of the bone or bone fixator

Sensor Review ◽  
2018 ◽  
Vol 38 (4) ◽  
pp. 405-411
Author(s):  
Zhanshe Guo ◽  
Zhaojun Guo ◽  
Xiangdang Liang ◽  
Shen Liu
Keyword(s):  
Good Condition ◽  
Force Sensor ◽  
Biomechanical Properties ◽  
Biomechanical Study ◽  
Sensor Calibration ◽  
Testing System ◽  
Static Force ◽  
Content Type ◽  
New Device ◽  
Bending Force

Purpose Biomechanical properties of bones and fixators are important. The aim of this study was to develop a new device to simulate the real mechanical environment and to evaluate biomechanical properties of the bone with a fixation device, including the static force and the fatigue characters. Design/methodology/approach In this paper, the device is mainly composed of three parts: pull-pressure transmission system, bending force applying system and torsion applying system, which can successfully simulate the pre-introduced pull-pressure force, bending force and torsion force, respectively. To prove the feasibility of the design, theoretical analysis is used. It is concluded from the simulated result that this scheme of design can successfully satisfy the request of the evaluation. Findings Finally, on the basis of the force sensor calibration, the static force experiment and fatigue experiment are carried out using the tibia of the sheep as the specimen. It is concluded from the result that the relationship between the micro displacement and the applied axial force is nearly linear. Under the condition of 1 Hz in frequency, 500 N in loading force and 18,000 reciprocating cycles, the bone fixator can still be in good condition, which proves the feasibility of the design. Originality/value Biomechanical properties of bones and fixators are studied by researchers. However, few simulate a real force environment and combine forces in different directions. So a novel system is designed and fabricated to evaluate the biomechanical properties of the bones and fixators. Results of the experiments show that this new system is reliable and stable, which can support the biomechanical study and clinical treatment.

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