scholarly journals Compressive Properties and Hydraulic Permeability of Human Meniscus: Relationships With Tissue Structure and Composition

2021 ◽  
Vol 8 ◽  
Author(s):  
Andy Morejon ◽  
Christopher D. Norberg ◽  
Massimiliano De Rosa ◽  
Thomas M. Best ◽  
Alicia R. Jackson ◽  
...  
Keyword(s):  
Water Content ◽  
Fluid Transport ◽  
Hydraulic Permeability ◽  
Transport Parameter ◽  
Compressive Properties ◽  
Total Load ◽  
Meniscal Tissue ◽  
Curve Fit ◽  
Sample Orientation ◽  
Weak Negative Correlation

The meniscus is crucial in maintaining knee function and protecting the joint from secondary pathologies, including osteoarthritis. The meniscus has been shown to absorb up to 75% of the total load on the knee joint. Mechanical behavior of meniscal tissue in compression can be predicted by quantifying the mechanical parameters including; aggregate modulus (H) and Poisson modulus (ν), and the fluid transport parameter: hydraulic permeability (K). These parameters are crucial to develop a computational model of the tissue and for the design and development of tissue engineered scaffolds mimicking the native tissue. Hence, the objective of this study was to characterize the mechanical and fluid transport properties of human meniscus and relate them to the tissue composition. Specimens were prepared from the axial and the circumferential anatomical planes of the tissue. Stress relaxation tests yielded the H, while finite element modeling was used to curve fit for ν and K. Correlations of moduli with water and glycosaminoglycans (GAGs) content were investigated. On average H was found to be 0.11 ± 0.078 MPa, ν was 0.32 ± 0.057, and K was 2.9 ± 2.27 × 10−15 m4N−1s−1. The parameters H, ν, and K were not found to be statistically different across compression orientation or compression level. Water content of the tissue was 77 ± 3.3% while GAG content was 8.79 ± 1.1%. Interestingly, a weak negative correlation was found between H and water content (R2 ~ 34%) and a positive correlation between K and GAG content (R2 ~ 53%). In conclusion, while no significant differences in transport and compressive properties can be found across sample orientation and compression levels, data trends suggest potential relationships between magnitudes of H and K, and GAG content.

Contributions of Proteoglycans to the Biotransport and Electrical Properties of Articular Cartilage: An Experimental Study

2013 ◽  
Author(s):  
Xin Gao ◽  
Lingtu Meng ◽  
Chun-Yuh C. Huang ◽  
Weiyong Gu
Keyword(s):  
Electrical Properties ◽  
Water Content ◽  
Interstitial Fluid ◽  
Swelling Pressure ◽  
Biomechanical Properties ◽  
Fixed Charge ◽  
Hydraulic Permeability ◽  
Electric Effects ◽  
The Relationship ◽  
Effective Pore Size

Proteoglycans (PGs) are one of the major components in the extracellular matrix (ECM) of cartilage, and are negatively charged due to the charged groups attached to their backbone (i.e., fixed charge groups). PGs play substantial roles in the mechanical, biotransport and electrical events within the tissue.3,7 More specifically, swelling pressure generated by the interaction between fixed charge groups and ionic interstitial fluid enhances cartilage’s capacity of load-bearing. In addition, biotransport properties (e.g., hydraulic permeability) and electrical properties (e.g., electrical conductivity) have been shown to be affected by water content (i.e., porosity) and fixed charge density (FCD).2–4 The alteration of proteoglycan content will affect the tissue FCD and water content, which could cause the changes in biomechanical, biotransport and electrical properties of the cartilage. The relationship between the PG content and biomechanical properties has been widely studied,6,8 but the knowledge on the effects of PG content on biotransport and electrical properties is limited.1 It is not clear whether the dependences of biotransport and electrical properties on PG content are mainly due to electric effects through the FCD associated with PGs or due to hindrance effects related to the effective pore size (i.e., water content) of the tissue. Therefore, the objectives of this study were (1) to investigate the effects of PG content on cartilage biotransport and electrical properties, (2) to analyze whether these effects are caused by changes of water content or FCD.

scholarly journals Multiscale Poroviscoelastic Compressive Properties of Mouse Supraspinatus Tendons Are Altered in Young and Aged Mice

2018 ◽  
Vol 140 (5) ◽  
Author(s):  
Brianne K. Connizzo ◽  
Alan J. Grodzinsky
Keyword(s):  
Rotator Cuff ◽  
Structural Parameters ◽  
Hydraulic Permeability ◽  
Aged Mouse ◽  
Compressive Properties ◽  
External Compression ◽  
Tendon Degeneration ◽  
Compressive Response ◽  
Age Related ◽  
Age Related Changes

Rotator cuff disorders are one of the most common causes of shoulder pain and disability in the aging population but, unfortunately, the etiology is still unknown. One factor thought to contribute to the progression of disease is the external compression of the rotator cuff tendons, which can be significantly increased by age-related changes such as muscle weakness and poor posture. The objective of this study was to investigate the baseline compressive response of tendon and determine how this response is altered during maturation and aging. We did this by characterizing the compressive mechanical, viscoelastic, and poroelastic properties of young, mature, and aged mouse supraspinatus tendons using macroscale indentation testing and nanoscale high-frequency AFM-based rheology testing. Using these multiscale techniques, we found that aged tendons were stiffer than their mature counterparts and that both young and aged tendons exhibited increased hydraulic permeability and energy dissipation. We hypothesize that regional and age-related variations in collagen morphology and organization are likely responsible for changes in the multiscale compressive response as these structural parameters may affect fluid flow. Importantly, these results suggest a role for age-related changes in the progression of tendon degeneration, and we hypothesize that decreased ability to resist compressive loading via fluid pressurization may result in damage to the extracellular matrix (ECM) and ultimately tendon degeneration. These studies provide insight into the regional multiscale compressive response of tendons and indicate that altered compressive properties in aging tendons may be a major contributor to overall tendon degeneration.

scholarly journals Characteristics, Performance of Blend CA/SPEEK Ultrafiltration Membranes Prepared by Phase Inversion Method using PEG 600 as an Additive

2017 ◽  
Vol 10 (1) ◽  
Author(s):  
G. Arthanareeswaran ◽  
N. Anatharaman ◽  
M. Raajenthiren
Keyword(s):  
Polyethylene Glycol ◽  
Water Content ◽  
Phase Inversion ◽  
Polymer Composition ◽  
Inversion Method ◽  
Hydraulic Permeability ◽  
Equilibrium Water Content ◽  
Ultrafiltration Membranes ◽  
Phase Inversion Method ◽  
Peg 600

Flat sheet asymmetric polymeric membranes is prepared by phase inversion method from homogeneous solution of 17.5 wt% cellulose acetate (CA) and sulfonated poly ether ether ketone (SPEEK) with polar solvent of N, N’– dimethylformamide (DMF). The different concentration of polyethylene glycol is used as the polymeric additives in the CA/SPEEK casting solution. The effects of polyethylene glycol 600 (PEG 600) concentration on the structure and performance of CA/SPEEK ultrafiltration membranes were investigated in more detail. The optimal preparation conditions were: 17.5 wt% total polymer composition, 65/35 wt% CA/SPEEK blend composition and 10 wt% PEG 600. The permeation performances of the membranes were evaluated in terms of pure water flux, equilibrium water content, hydraulic permeability, and solute rejection. The morphology and structure of the resulting membranes were observed by scanning electron microscope (SEM). CA/SPEEK membranes with higher concentration of 10 wt% PEG have higher PWF and equilibrium water content due to high porosity. With increase in PEG concentration from 0 to 10 wt%, the PWF increases from 129 to 259 lm–2h–1 in 65/35 wt% of CA/SPEEK as blend. When increasing concentration of PEG is substituted for SPEEK in proportion to form a homogeneous blend, the membrane hydraulic resistance reduces from 9.2 to 2.9 kPa/l.m–2.h–1for blend membranes with 0 to 10 wt % PEG 600 at 95/5 wt % CA/SPEEK composition. Solution of proteins of different molecular weight was used to study the permeation performance of prepared membranes using a batch membrane cell of 400 ml capacity.

Distributed modeling of osmotically driven fluid transport in peritoneal dialysis: theoretical and computational investigations

2009 ◽  
Vol 296 (6) ◽  
pp. H1960-H1968 ◽  
Author(s):  
Jacek Waniewski ◽  
Joanna Stachowska-Pietka ◽  
Michael F. Flessner
Keyword(s):  
Peritoneal Dialysis ◽  
Fluid Transport ◽  
Present Report ◽  
Capillary Wall ◽  
Distributed Model ◽  
Hydraulic Permeability ◽  
Transport Parameters ◽  
Distributed Modeling ◽  
Dialysis Solution ◽  
Osmotic Agent

Based on a distributed model of peritoneal transport, in the present report, a mathematical theory is presented to explain how the osmotic agent in the peritoneal dialysis solution that penetrates tissue induces osmotically driven flux out of the tissue. The relationships between phenomenological transport parameters (hydraulic permeability and reflection coefficient) and the respective specific transport parameters for the tissue and the capillary wall are separately described. Closed formulas for steady-state flux across the peritoneal surface and for hydrostatic pressure at the opposite surface are obtained using an approximate description of the concentration profile of the osmotic agent within the tissue by exponential function. A case of experimental study with mannitol as the osmotic agent in the rat abdominal wall is shown to be well described by our theory and computer simulations and to validate the applied approximations. Furthermore, clinical dialysis with glucose as the osmotic agent is analyzed, and the effective transport rates and parameters are derived from the description of the tissue and capillary wall.

Changes of Peritoneal Transport Parameters with Time on Dialysis: Assessment with Sequential Peritoneal Equilibration Test

2017 ◽  
Vol 40 (11) ◽  
pp. 595-601 ◽  
Author(s):  
Jacek Waniewski ◽  
Stefan Antosiewicz ◽  
Daniel Baczynski ◽  
Jan Poleszczuk ◽  
Mauro Pietribiasi ◽  
...  
Keyword(s):  
Solute Transport ◽  
Fluid Transport ◽  
Transport Processes ◽  
Model Parameters ◽  
Hydraulic Permeability ◽  
Transport Parameters ◽  
Peritoneal Equilibration Test ◽  
Transport Barrier ◽  
Pore Model ◽  
Peritoneal Transport

Background Sequential peritoneal equilibration test (sPET) is based on the consecutive performance of the peritoneal equilibration test (PET, 4-hour, glucose 2.27%) and the mini-PET (1-hour, glucose 3.86%), and the estimation of peritoneal transport parameters with the 2-pore model. It enables the assessment of the functional transport barrier for fluid and small solutes. The objective of this study was to check whether the estimated model parameters can serve as better and earlier indicators of the changes in the peritoneal transport characteristics than directly measured transport indices that depend on several transport processes. Methods 17 patients were examined using sPET twice with the interval of about 8 months (230 ± 60 days). Results There was no difference between the observational parameters measured in the 2 examinations. The indices for solute transport, but not net UF, were well correlated between the examinations. Among the estimated parameters, a significant decrease between the 2 examinations was found only for hydraulic permeability LpS, and osmotic conductance for glucose, whereas the other parameters remained unchanged. These fluid transport parameters did not correlate with D/P for creatinine, although the decrease in LpS values between the examinations was observed mostly for patients with low D/P for creatinine. Conclusions We conclude that changes in fluid transport parameters, hydraulic permeability and osmotic conductance for glucose, as assessed by the pore model, may precede the changes in small solute transport. The systematic assessment of fluid transport status needs specific clinical and mathematical tools beside the standard PET tests.

scholarly journals Effect of the Melt Pool Boundary Network on the Anisotropic Mechanical Properties of Selective Laser Melted 304L

2021 ◽  
Vol 5 (4) ◽  
pp. 110
Author(s):  
Myranda Spratt ◽  
Joseph W. Newkirk ◽  
Okanmisope Fashanu ◽  
K. Chandrashekhara
Keyword(s):  
Mechanical Properties ◽  
Numerical Models ◽  
304L Stainless Steel ◽  
Compressive Properties ◽  
Laser Melting ◽  
Boundary Concentration ◽  
Melt Pool ◽  
Anisotropic Mechanical Properties ◽  
Anisotropic Plastic ◽  
Weak Negative Correlation

Anisotropic mechanical properties are a well-known issue in selective laser melted parts. The microstructure produced by selective laser melting (SLM) is directional, including the solidified melt pool structures and grains. This work investigates the melt pool boundary’s effects on 304L stainless steel’s compressive properties. 304L stainless steel solid cylinders were built using a pulse laser SLM machine in four directions using three hatch angle rotations: 0°, 67°, and 105°. The twelve samples were compression tested, and the results were analyzed. Numerical models were also created with the different hatch angles and directions. The melt pool boundary network (MPBN) in each build was tracked using the model across multiple planes. Results showed that both the hatch angle and build orientation influenced the concentration of melt pool boundaries present in the manufactured samples. A weak negative correlation of compressive strength to the melt pool boundaries’ concentration was also observed, indicating that the melt pool boundary concentration negatively affected the material’s strength. Local anisotropic plastic deformation was also observed in some of the compressed samples. In those samples, it was observed that directions that plastically deformed more also contained higher concentration of the melt pool boundaries.

Regional and Fiber Orientation Dependent Shear Properties and Anisotropic Modeling of Bovine Meniscus

2011 ◽  
Author(s):  
Adam C. Abraham ◽  
Christian R. Edwards ◽  
Gregory M. Odegard ◽  
Tammy L. Haut Donahue
Keyword(s):  
Stress Distribution ◽  
Water Content ◽  
Applied Stress ◽  
Collagen Fibril ◽  
Anisotropic Material ◽  
Fiber Orientation ◽  
Interstitial Water ◽  
Shear Properties ◽  
Material Response ◽  
Meniscal Tissue

The meniscus is a multiphase material composed of interstitial water, collagen, glycosaminoglycans (GAGs), and fibrochondrocytes [2, 9]. The microstructure of the meniscus consists of superficial randomly orientated fibers providing a smooth lubricating surface, with the deep portion containing circumferentially oriented fibers intermixed with sparse radial tie fibers [12]. This layered morphology evokes an anisotropic material response with regard to axial, radial and circumferential directions relative to primary collagen fibril orientations [1, 4, 6, 8, 10, 13]. In addition to intrinsic fiber orientation influencing mechanical differences in meniscal tissue, GAG and water content have previously been shown to be regionally dependent within the meniscus, elucidating provincial specificity of the applied stress distribution within the joint.

Mechanical Characterization of Contact Lenses by Microindentation: Constant Velocity and Relaxation Testing

2008 ◽  
Author(s):  
Sung Jin Lee ◽  
Gerald R. Bourne ◽  
Xiaoming Chen ◽  
W. Gregory Sawyer ◽  
Malisa Sarntinoranont
Keyword(s):  
Material Properties ◽  
Fluid Transport ◽  
Contact Lenses ◽  
Solid Phase ◽  
Clinical Performance ◽  
Hydraulic Permeability ◽  
Soft Contact Lenses ◽  
Speed Up ◽  
Design And Testing

Mechanical and fluid transport properties of soft contact lenses may influence clinical performance, e.g., on-eye movement, fitting, and wettability, and may be related to the occurrence of complications, e.g. lesions [1, 2]. In the mechanical assessment of soft hydrated materials, indentation is increasingly being used because of its nondestructive methods for testing these material properties allow for multiple tests to be performed on the same sample, which will speed up the design and testing process for hydrogel contact lenses. [3]. Contact lens hydrogels may be described as a biphasic material. The material properties governing biphasic behavior are the Young’s modulus of the solid phase, Poisson ratio’s, and hydraulic permeability which is measure of fluid conductance in porous media. Previous studies of indentation of biphasic media have been completed by Mow and coworkers [4]. Also, computational finite element (FE) models have also been developed [5].

scholarly journals Compressive Remodeling Alters Fluid Transport Properties of Collagen Networks – Implications for Tumor Growth

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
J. Ferruzzi ◽  
M. Sun ◽  
A. Gkousioudi ◽  
A. Pilvar ◽  
D. Roblyer ◽  
...  
Keyword(s):  
Tumor Growth ◽  
Fluid Transport ◽  
Type I Collagen ◽  
Fluid Pressure ◽  
Hydraulic Permeability ◽  
Type I ◽  
Ecm Remodeling ◽  
Epithelial Cancers ◽  
The Matrix ◽  
Fluid Pressurization

AbstractBiomechanical alterations to the tumor microenvironment include accumulation of solid stresses, extracellular matrix (ECM) stiffening and increased fluid pressure in both interstitial and peri-tumoral spaces. The relationship between interstitial fluid pressurization and ECM remodeling in vascularized tumors is well characterized, while earlier biomechanical changes occurring during avascular tumor growth within the peri-tumoral ECM remain poorly understood. Type I collagen, the primary fibrous ECM constituent, bears load in tension while it buckles under compression. We hypothesized that tumor-generated compressive forces cause collagen remodeling via densification which in turn creates a barrier to convective fluid transport and may play a role in tumor progression and malignancy. To better understand this process, we characterized the structure-function relationship of collagen networks under compression both experimentally and computationally. Here we show that growth of epithelial cancers induces compressive remodeling of the ECM, documented in the literature as a TACS-2 phenotype, which represents a localized densification and tangential alignment of peri-tumoral collagen. Such compressive remodeling is caused by the unique features of collagen network mechanics, such as fiber buckling and cross-link rupture, and reduces the overall hydraulic permeability of the matrix.

A Biphasic Model for Micro-Indentation of a Hydrogel-Based Contact Lens

2006 ◽  
Vol 129 (2) ◽  
pp. 156-163 ◽  
Author(s):  
Xiaoming Chen ◽  
Alison C. Dunn ◽  
W. Gregory Sawyer ◽  
Malisa Sarntinoranont
Keyword(s):  
Young’S Modulus ◽  
Contact Lens ◽  
Fluid Transport ◽  
Contact Lenses ◽  
Young's Modulus ◽  
Contact Region ◽  
Solid Matrix ◽  
Hydraulic Permeability ◽  
Biphasic Finite Element ◽  
Micro Indentation

The stiffness and hydraulic permeability of soft contact lenses may influence its clinical performance, e.g., on-eye movement, fitting, and wettability, and may be related to the occurrence of complications; e.g., lesions. It is therefore important to determine these properties in the design of comfortable contact lenses. Micro-indentation provides a nondestructive means of measuring mechanical properties of soft, hydrated contact lenses. However, certain geometrical and material considerations must be taken into account when analyzing output force-displacement (F-D) data. Rather than solely having a solid response, mechanical behavior of hydrogel contact lenses can be described as the coupled interaction between fluid transport through pores and solid matrix deformation. In addition, indentation of thin membranes (∼100μm) requires special consideration of boundary conditions at lens surfaces and at the indenter contact region. In this study, a biphasic finite element model was developed to simulate the micro-indentation of a hydrogel contact lens. The model accounts for a curved, thin hydrogel membrane supported on an impermeable mold. A time-varying boundary condition was implemented to model the contact interface between the impermeable spherical indenter and the lens. Parametric studies varying the indentation velocities and hydraulic permeability show F-D curves have a sensitive region outside of which the force response reaches asymptotic limits governed by either the solid matrix (slow indentation velocity, large permeability) or the fluid transport (high indentation velocity, low permeability). Using these results, biphasic properties (Young’s modulus and hydraulic permeability) were estimated by fitting model results to F-D curves obtained at multiple indentation velocities (1.2 and 20μm∕s). Fitting to micro-indentation tests of Etafilcon A resulted in an estimated permeability range of 1.0×10−15 to 5.0×10−15m4∕Ns and Young’s modulus range of 130to170kPa.

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