scholarly journals Characterization of scar tissue biomechanics during adult murine flexor tendon healing

2021 ◽  
Author(s):  
Antonion Korcari ◽  
Alayna E Loiselle ◽  
Mark R Buckley
Keyword(s):  
Mechanical Properties ◽  
Material Properties ◽  
Healing Process ◽  
Tendon Healing ◽  
Scar Tissue ◽  
Element Analysis ◽  
Material Quality ◽  
Treatment Regimens ◽  
Tangent Moduli ◽  
Experimental Findings

Tendon injuries are very common and result in significant impairments in mobility and quality of life. During healing, tendons produce a scar at the injury site, characterized by abundant and disorganized extracellular matrix and by permanent deficits in mechanical integrity compared to healthy tendon. Although a significant amount of work has been done to understand the healing process of tendons and to develop potential therapeutics for tendon regeneration, there is still a significant gap in terms of assessing the direct effects of therapeutics on the functional and material quality specifically of the scar tissue, and thus, on the overall tendon healing process. In this study, we focused on characterizing the mechanical properties of only the scar tissue in flexor digitorum longus (FDL) tendons during the proliferative and remodeling healing phases and comparing these properties with the mechanical properties of the composite healing tissue. Our method was sensitive enough to identify significant differences in structural and material properties between the scar and tendon-scar composite tissues. To account for possible inaccuracies due to the small aspect ratio of scar tissue, we also applied inverse finite element analysis (iFEA) to compute mechanical properties based on simulated tests with accurate specimen geometries and boundary conditions. We found that the scar tissue linear tangent moduli calculated from iFEA were not significantly different from those calculated experimentally at all healing timepoints, validating our experimental findings, and suggesting the assumptions in our experimental calculations were accurate. Taken together, this study first demonstrates that due to the presence of uninjured stubs, testing composite healing tendons without isolating the scar tissue overestimates the material properties of the scar itself. Second, our scar isolation method promises to enable more direct assessment of how different treatment regimens (e.g., cellular ablation, biomechanical and/or biochemical stimuli, tissue engineered scaffolds) affect scar tissue function and material quality in multiple different types of tendons.

Cytocompatibility and Material Properties of Poly-carbonate Urethane/Carbon Nanofiber Composites for Neural Applications

2003 ◽  
Vol 774 ◽  
Author(s):  
Janice L. McKenzie ◽  
Michael C. Waid ◽  
Riyi Shi ◽  
Thomas J. Webster
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanofibers ◽  
Material Properties ◽  
Carbon Nanofiber ◽  
Scar Tissue ◽  
Tissue Response ◽  
Positive Interactions ◽  
Weight Percentage ◽  
Poly Carbonate

AbstractCarbon nanofibers possess excellent conductivity properties, which may be beneficial in the design of more effective neural prostheses, however, limited evidence on their cytocompatibility properties exists. The objective of the present in vitro study was to determine cytocompatibility and material properties of formulations containing carbon nanofibers to predict the gliotic scar tissue response. Poly-carbonate urethane was combined with carbon nanofibers in varying weight percentages to provide a supportive matrix with beneficial bulk electrical and mechanical properties. The substrates were tested for mechanical properties and conductivity. Astrocytes (glial scar tissue-forming cells) were seeded onto the substrates for adhesion. Results provided the first evidence that astrocytes preferentially adhered to the composite material that contained the lowest weight percentage of carbon nanofibers. Positive interactions with neurons, and, at the same time, limited astrocyte functions leading to decreased gliotic scar tissue formation are essential for increased neuronal implant efficacy.

scholarly journals Regenerative Rehabilitation in Injuries of Tendons

2021 ◽  
Vol 3 (2) ◽  
pp. 192-206
Author(s):  
Sergey G. Sсherbak ◽  
Stanislav V. Makarenko ◽  
Olga V. Shneider ◽  
Tatyana A. Kamilova ◽  
Alexander S. Golota
Keyword(s):  
Mechanical Properties ◽  
Type I Collagen ◽  
Transforming Growth Factor ◽  
Healing Process ◽  
Tendon Healing ◽  
Tendon Injuries ◽  
Type I ◽  
Differentiation Markers ◽  
Postoperative Rehabilitation ◽  
Potent Inducer

The mechanical properties of tendons are thought to be affected by different loading levels. Changes in the mechanical properties of tendons, such as stiffness, have been reported to influence the risk of tendon injuries chiefly in athletes and the elderly, thereby affecting motor function execution. Unloading resulted in reduced tendons stiffness, and resistance exercise exercise counteracts this. Transforming growth factor-1 is a potent inducer of type I collagen and mechanosensitive genes encoding tenogenic differentiation markers expression which play critical roles in tendon tissue formation, tendon healing and their adaptation during exercise. In recent years, our understanding of the molecular biology of tendons growth and repair has expanded. It is probable that the next advance in the treatment of tendon injuries will result from the application of this basic science knowledge and the clinical solution will encompass not only the the best postoperative rehabilitation protocols, but also the optimal biological modulation of the healing process.

scholarly journals Finite element analysis relating shape, material properties, and dimensions of taenioglossan radular teeth with trophic specialisations in Paludomidae (Gastropoda)

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Wencke Krings ◽  
Jordi Marcé-Nogué ◽  
Stanislav N. Gorb
Keyword(s):  
Mechanical Properties ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Material Properties ◽  
Stress And Strain ◽  
Plant Surface ◽  
Element Analysis ◽  
The Finite Element Analysis ◽  
Force Volume ◽  
General Size

AbstractThe radula, a chitinous membrane with embedded tooth rows, is the molluscan autapomorphy for feeding. The morphologies, arrangements and mechanical properties of teeth can vary between taxa, which is usually interpreted as adaptation to food. In previous studies, we proposed about trophic and other functional specialisations in taenioglossan radulae from species of African paludomid gastropods. These were based on the analysis of shape, material properties, force-resistance, and the mechanical behaviour of teeth, when interacting with an obstacle. The latter was previously simulated for one species (Spekia zonata) by the finite-element-analysis (FEA) and, for more species, observed in experiments. In the here presented work we test the previous hypotheses by applying the FEA on 3D modelled radulae, with incorporated material properties, from three additional paludomid species. These species forage either on algae attached to rocks (Lavigeria grandis), covering sand (Cleopatra johnstoni), or attached to plant surface and covering sand (Bridouxia grandidieriana). Since the analysed radulae vary greatly in their general size (e.g. width) and size of teeth between species, we additionally aimed at relating the simulated stress and strain distributions with the tooth sizes by altering the force/volume. For this purpose, we also included S. zonata again in the present study. Our FEA results show that smaller radulae are more affected by stress and strain than larger ones, when each tooth is loaded with the same force. However, the results are not fully in congruence with results from the previous breaking stress experiments, indicating that besides the parameter size, more mechanisms leading to reduced stress/strain must be present in radulae.

Impact of Grain Structure and Material Properties on Via Extrusion in 3D Interconnects

2015 ◽  
Vol 12 (3) ◽  
pp. 118-122 ◽  
Author(s):  
Tengfei Jiang ◽  
Chenglin Wu ◽  
Jay Im ◽  
Rui Huang ◽  
Paul S. Ho
Keyword(s):  
Mechanical Properties ◽  
Finite Element Analysis ◽  
Grain Size ◽  
Finite Element ◽  
Analytical Model ◽  
Material Properties ◽  
Grain Structure ◽  
Element Analysis ◽  
Silicon Vias ◽  
The Relationship

In this article, the effects of Cu microstructure on the mechanical properties and extrusion of through-silicon vias (TSVs) were studied based on two types of TSVs with different microstructure. A direct correlation was found between the grain size and the mechanical properties of the vias. Both an analytical model and finite element analysis (FEA) were used to establish the relationship between the mechanical properties and via extrusion. The effect of via/Si interface on extrusion was also studied by FEA. The results suggest small and uniform grains in the Cu vias, as well as stronger interfaces between the via and Si led to smaller via extrusion, and are thus preferable for reduced via extrusion failure and improved TSV reliability.

scholarly journals Finite Element Analysis Relating Shape, Material Properties, and Dimensions of Taenioglossan Radular Teeth with Trophic Specialisations in Paludomidae (Gastropoda)

2021 ◽  
Author(s):  
Wencke Krings ◽  
Jordi Marcé-Nogué ◽  
Stanislav N. Gorb
Keyword(s):  
Mechanical Properties ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Mechanical Behaviour ◽  
Material Properties ◽  
Stress And Strain ◽  
Plant Surface ◽  
Element Analysis ◽  
The Finite Element Analysis ◽  
Force Volume

Abstract The radula, a chitinous membrane with embedded tooth rows, is the molluscan autapomorphy for feeding. The morphologies, arrangements and mechanical properties of teeth can vary between taxa, which is usually interpreted as adaptation to food. In previous studies, we proposed about trophic and other functional specialisations in taenioglossan radulae from species of African paludomid gastropods. These were based on the analysis of shape, material properties, force-resistance, and the mechanical behaviour of teeth, when interacting with an obstacle, which was previously simulated for one species (Spekia) by the finite-element-analysis (FEA) and, for more species, observed in experiments. In the here presented work, we test the previous hypotheses by applying the FEA on 3D modelled radulae, with incorporated material properties, from three additional paludomid species. These species forage either on algae attached to rocks (Lavigeria), covering sand (Cleopatra), or attached to plant surface and covering sand (Bridouxia). Since the analysed radulae vary greatly in their size between species, we additionally aimed at relating the simulated stress and strain distributions with the tooth sizes by altering the force/volume. For this purpose, we also included Spekia again in the present study. Our FEA results show that smaller radulae are more affected by stress and strain than larger ones, when each tooth is loaded with the same force. However, the results are not fully in congruence with results from the previous breaking stress experiments, indicating that besides the parameter size, more mechanisms leading to reduced stress/strain must be present in radulae.

Discretization Errors of Random Fields in Finite Element Analysis

2014 ◽  
Vol 553 ◽  
pp. 405-409 ◽  
Author(s):  
J. Huang ◽  
D.V. Griffiths ◽  
Andrei V. Lyamin ◽  
Kristian Krabbenhoft ◽  
Scott William Sloan
Keyword(s):  
Field Theory ◽  
Mechanical Properties ◽  
Finite Element ◽  
Material Properties ◽  
Random Fields ◽  
Element Analysis ◽  
Element Mesh ◽  
Random Field Theory ◽  
Correlation Lengths ◽  
Discretization Errors

The mechanical properties of natural materials such as rocks and soils vary spatially. This randomness is usually modelled by random field theory so that the material properties can be specified at each point in space. When these point-wise material properties are mapped onto a finite element mesh, discretization errors are inevitable. In this study, the discretization errors are studied and suggestions for element sizes in relation with spatial correlation lengths are given.

Finite Element Analysis of Mechanical Behavior of Light-Weight Mobile FRP Bridge

2010 ◽  
Vol 163-167 ◽  
pp. 1995-1998
Author(s):  
Xin Huang ◽  
Zai Gen Mu ◽  
Peng Feng
Keyword(s):  
Mechanical Properties ◽  
Finite Element ◽  
Material Properties ◽  
Weight Ratio ◽  
High Strength ◽  
Light Weight ◽  
The Finite Element Method ◽  
Element Analysis ◽  
Superior Corrosion Resistance ◽  
Main Material

As composite materials have advantages of high strength-to-weight ratio and superior corrosion resistance properties, it is used in emergencies in the construction of mobile bridges as the preferred material. However, In contrast to traditional steel or aluminum to the movement of the bridge as the main material, the original bridge forms need to be improved in order to reach the full of FRP material properties. In this paper, to study the domestic light-weight mobile FRP Bridge, the finite element method is used to analysis the mechanical properties of bridge.

Mapping the Mechanical Properties of Cancellous Bone from the Femoral Head

2015 ◽  
Vol 801 ◽  
pp. 273-277
Author(s):  
Karla Noemy Kun ◽  
Lorand Kun ◽  
Ramona Nagy ◽  
Karoly Menyhardt ◽  
Dana Silaghi-Perju ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Femoral Head ◽  
Cancellous Bone ◽  
Material Properties ◽  
Compression Testing ◽  
Experimental Program ◽  
Element Analysis

This work presents an experimental program to determine the mechanical properties of cancellous bone in the femoral head as a function of location. To achieve this several specimens of cancellous bone of approximately 10 mm height and 10 mm diameter were obtained from one human femoral head, starting the sampling from its main loading compressive direction. All specimens underwent compression testing in order to determine the mechanical properties of each specimen and thus a properties map of the cancellous bone in the femoral head was obtained. Based on the results a parametric file with material properties was created in order to be used by professionals in finite element analysis programs.

scholarly journals Finite Element-Based Simulation of Cooling Rate on the Material Properties of an Automobile Silent Block

2020 ◽  
Vol 2020 ◽  
pp. 1-8
Author(s):  
Burak Öztürk ◽  
Fuat Kara
Keyword(s):  
Mechanical Properties ◽  
Finite Element ◽  
Cooling Rate ◽  
Material Properties ◽  
High Speed ◽  
Tensile Tests ◽  
Isothermal Transformation ◽  
Element Analysis ◽  
Front Suspension ◽  
Safety Coefficient

The aluminum silent block is the part that connects the front suspension mounting and the road wheels. These products are used in high-speed cars and are subject to high engineering stresses. Over time, fractures occur in the connection part of these products due to insufficient strength. These problems are related to production metallurgy, which led to the concept of this study. During mass production, these parts are manufactured using the aluminum extrusion method. In this study, a rapid cooling process using water was applied, with the aim of improving the mechanical properties of the connecting part exposed to high dynamic loads. Samples were taken from the regions of these products which differed in thickness and width, and microhardness and tensile tests were performed for each region. The effects of both the extrusion cooling rate and the regional flash cooling on the material properties were then characterized. As a result of the isothermal transformation, the grain size in the microstructure of the material had shrunk. According to the findings, in this type of production, an average increase in strength of 25% was observed in the parts of the material subjected to maximum stress. The stress and safety coefficient values were found using finite element analysis, and curves were then drawn showing the differences in the safety coefficient values from the different points. As a result of cooperation between university and industry, the material and mechanical properties of an automobile part were improved in this study. This research has shown that, in terms of the accuracy of the results, it is very important to consider the variations in different regions of the product when defining the mechanical properties of any material produced by applying casting, heat treatment, and plastic forming methods.

Inverse Method to Determine Mechanical Properties of Thin Film by Nanoindentation and Finite Element Analysis

2006 ◽  
Vol 326-328 ◽  
pp. 219-222 ◽  
Author(s):  
Dong Cheon Baek ◽  
Soon Bok Lee
Keyword(s):  
Thin Film ◽  
Mechanical Properties ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Young’S Modulus ◽  
Material Properties ◽  
Inverse Method ◽  
Young's Modulus ◽  
Displacement Curve ◽  
Element Analysis

As a reliable tool to measure the Young’s modulus, nanoindention technique has been used widely recently. In this paper, nanoindetation technique was overviewed with its advantage and limitation and a new method was proposed to determine material properties of film, i.e. both Young’s modulus E and Poisson’s ratio ν from load-displacement curve of shallow-depth indentation using ‘inverse method’.

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