Journal of the Mechanical Behavior of Biomedical MaterialsThis is an RSS file. You can use it to subscribe to this data in your favourite RSS reader, such as GoogleReader, or to display this data on your own website or blog. Subscribe to this data using MyMedWorm.Subscribe to this data using GoogleReader.Subscribe to this data using Bloglines.Subscribe to this data using MyYahoo.

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Different types of article in JMBBM.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
PMID: 19878896 [PubMed - in process] (Source: Journal of the Mechanical Behavior of Biomedical Materials)
Source: Journal of the Mechanical Behavior of Biomedical Materials - November 3, 2009 Category: Materials Science Authors: Taylor D Tags: J Mech Behav Biomed Mater Source Type: journals

Effect of fluorapatite additive on densification and mechanical properties of tricalcium phosphate.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Tricalcium phosphate and synthesized fluorapatite powder were mixed in order to elaborate biphasic composites. The samples were characterized by X-ray diffraction, differential thermal analysis, infrared spectroscopy, scanning electron microscopy and by an analysis using (31)P nuclear magnetic resonance. The sintering of tricalcium phosphate with different percentages of fluorapatite (13.26 wt%; 19.9 wt%; 33.16 wt% and 40 wt%) indicates the evolution of the microstructure, densification and mechanical properties. The Brazilian test was used to measure the rupture strength of the sintered biphasic composites. The mechan...
Source: Journal of the Mechanical Behavior of Biomedical Materials - November 3, 2009 Category: Materials Science Authors: Bouslama N, Ben Ayed F, Bouaziz J Tags: J Mech Behav Biomed Mater Source Type: journals

An entropy spring model for the Young's modulus change of biodegradable polymers during biodegradation.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
This paper presents a model for the change in Young's modulus of biodegradable polymers due to hydrolysis cleavage of the polymer chains. The model is based on the entropy spring theory for amorphous polymers. It is assumed that isolated polymer chain cleavage and very short polymer chains do not affect the entropy change in a linear biodegradable polymer during its deformation. It is then possible to relate the Young's modulus to the average molecular weight in a computer simulated hydrolysis process of polymer chain sessions. The experimental data obtained by Tsuji [Tsuji, H., 2002. Autocatalytic hydrolysis of amorph...
Source: Journal of the Mechanical Behavior of Biomedical Materials - November 3, 2009 Category: Materials Science Authors: Wang Y, Han X, Pan J, Sinka C Tags: J Mech Behav Biomed Mater Source Type: journals

Minimizing specimen length in elastic testing of end-constrained cancellous bone.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
End-constraint is needed when performing tensile and compressive testing of cancellous bone so that frictional and structural end-effects are minimized and the mechanical properties are not underestimated. Since many end-constrained testing techniques are limited to certain sites and species by the large specimen sizes required, reductions in overall specimen length would be advantageous. The following study examines the effect of specimen gauge length and aspect ratio on the elastic tensile testing of cancellous bone from the bovine femoral condyle. Three different nominal gauge lengths (10, 16, 22 mm) were examined a...
Source: Journal of the Mechanical Behavior of Biomedical Materials - November 3, 2009 Category: Materials Science Authors: Lievers WB, Waldman SD, Pilkey AK Tags: J Mech Behav Biomed Mater Source Type: journals

Mechanical evaluation by patient-specific finite element analyses demonstrates therapeutic effects for osteoporotic vertebrae.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Osteoporosis can lead to bone compressive fractures in the lower lumbar vertebrae. In order to assess the recovery of vertebral strength during drug treatment for osteoporosis, it is necessary not only to measure the bone mass but also to perform patient-specific mechanical analyses, since the strength of osteoporotic vertebrae is strongly dependent on patient-specific factors, such as bone shape and bone density distribution in cancellous bone, which are related to stress distribution in the vertebrae. In the present study, patient-specific general (not voxel) finite element analyses of osteoporotic vertebrae during d...
Source: Journal of the Mechanical Behavior of Biomedical Materials - November 3, 2009 Category: Materials Science Authors: Tawara D, Sakamoto J, Murakami H, Kawahara N, Oda J, Tomita K Tags: J Mech Behav Biomed Mater Source Type: journals

Development of biomedical porous titanium filled with medical polymer by in-situ polymerization of monomer solution infiltrated into pores.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In this study, for the fabrication of the abovementioned composite, a versatile process for filling a medical polymer into a porous metallic material has been developed using porous pure titanium (pTi) and polymethylmethacrylate (PMMA). Then, the tensile strength and Young's modulus of pTi filled with PMMA (pTi/PMMA) fabricated using this process are systematically investigated. The tensile strength of pTi can be improved by the PMMA filling. Particularly, the improvement in the tensile strength of pTi pretreated using a silane coupling agent before PMMA filling is greater than that of the non-pretreated pTi because the st...
Source: Journal of the Mechanical Behavior of Biomedical Materials - November 3, 2009 Category: Materials Science Authors: Nakai M, Niinomi M, Akahori T, Tsutsumi H, Itsuno S, Haraguchi N, Itoh Y, Ogasawara T, Onishi T, Shindoh T Tags: J Mech Behav Biomed Mater Source Type: journals

Mechanical characterisation of polyurethane elastomer for biomedical applications.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Mechanical testing and modelling of a material for biomedical applications have to be based on conditions representative of the application of interest. In this work, an ether-based polyurethane elastomer is used to build mock arteries. The aim is to study the behaviour of arteries under pulsatile loading conditions and how that behaviour changes with the development and progression of atherosclerosis. Polyurethane elastomers are widely used as biomaterials, e.g. in tube form for bypasses and catheters. However, their mechanical behaviour has not been extensively characterised. This work establishes the variations in t...
Source: Journal of the Mechanical Behavior of Biomedical Materials - November 3, 2009 Category: Materials Science Authors: Kanyanta V, Ivankovic A Tags: J Mech Behav Biomed Mater Source Type: journals

Investigation of the mechanical interaction of the trabecular core with an external shell using rapid prototype and finite element models.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The objective of this study was to investigate this interaction and to determine what effect it has on the ultimate strength of the whole bone. This objective was achieved by compression testing rapid prototype (RP) models of cylindrical trabecular bone cores, with and without an integral surrounding shell and incorporating increasing levels of artificially induced bone loss. Corresponding finite element (FE) models were generated and the load sharing of the shell and trabecular core was analysed under linear elastic loading conditions. The results of the physical RP model tests and corresponding FE analyses indicated that...
Source: Journal of the Mechanical Behavior of Biomedical Materials - November 3, 2009 Category: Materials Science Authors: Mc Donnell P, Harrison N, Lohfeld S, Kennedy O, Zhang Y, Mc Hugh PE Tags: J Mech Behav Biomed Mater Source Type: journals

Wear behavior of light-cured dental composites filled with porous glass-ceramic particles.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In this study, novel bioactive glass-ceramic powders exhibiting different nominal calcium-mica to fluorapatite ratios were used as fillers for light-cured dental composites. Wear tests on the resulting samples were undertaken using a micro-tribometer with a linear reciprocating ball-on-flat geometry using lubrication from artificial saliva. The surfaces of the worn composites were then evaluated using optical microscopy. In order to enhance matrix bonding, the surfaces of the different particulates were treated using hydrofluoric acid to provide a porous surface and the resulting surface morphology was evaluated using scan...
Source: Journal of the Mechanical Behavior of Biomedical Materials - November 3, 2009 Category: Materials Science Authors: Tan Y, Liu Y, Grover LM, Huang B Tags: J Mech Behav Biomed Mater Source Type: journals

A novel constitutive model of skeletal muscle taking into account anisotropic damage.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The purpose of this study is to develop a constitutive model of skeletal muscle that describes material anisotropy, viscoelasticity and damage of muscle tissue. A free energy function is described as the sum of volumetric elastic, isochoric elastic and isochoric viscoelastic parts. The isochoric elastic part is divided into two types of shear response and the response in the fiber direction. To represent the dependence of the mechanical properties on muscle activity, we incorporate a contractile element into the model. The viscoelasticity of muscle is modeled as a three-dimensional model constructed by extending the on...
Source: Journal of the Mechanical Behavior of Biomedical Materials - November 3, 2009 Category: Materials Science Authors: Ito D, Tanaka E, Yamamoto S Tags: J Mech Behav Biomed Mater Source Type: journals

Dependence of in vitro fatigue properties of PMMA bone cement on the polydispersity index of its powder.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Four variants of poly (methyl methacrylate) (PMMA) bone cement were used, the difference being in the method used to sterilize the powder (three different dosages of gamma irradiation and ethylene oxide gas) and, hence, in the molecular weight of the powder. For each cement powder, the number-average molecular weight and weight-average molecular weight (and, hence, the polydispersity index, PDI) were determined using gel permeation chromatography. For each of the cured cements, the fatigue lives (N(f)) of specimens, at loads corresponding to stresses (S) of +/-10.0 MPa, +/-12.5 MPa, +/-15.0 MPa, and +/-20.0 MPa, were d...
Source: Journal of the Mechanical Behavior of Biomedical Materials - November 3, 2009 Category: Materials Science Authors: Lewis G, Li Y Tags: J Mech Behav Biomed Mater Source Type: journals

Anisotropic swelling and mechanical behavior of composite bacterial cellulose-poly(acrylamide or acrylamide-sodium acrylate) hydrogels.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Bacterial cellulose-polyacrylamide (BC-PAAm) composite hydrogels are prepared by synthesis of PAAm networks inside the BC matrices. The behavior of these gels and of the ionic ones obtained via partial hydrolysis of BC-PAAm gels is studied under swelling and compressive deformation conditions. The dependences of the hydrogels' properties on the BC matrix preparation conditions, gel synthesis conditions and the BC content in the hydrogel compositions are studied. Two types of BC gel pellicle are used in the hydrogel synthesis, namely matrix pellicles subjected to pre-pressing (samples of series A) and those not subjecte...
Source: Journal of the Mechanical Behavior of Biomedical Materials - November 3, 2009 Category: Materials Science Authors: Buyanov AL, Gofman IV, Revel'skaya LG, Khripunov AK, Tkachenko AA Tags: J Mech Behav Biomed Mater Source Type: journals

Viscoelastic behavior of discrete human collagen fibrils.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In conclusion, the present work provides direct evidence of viscoelastic behavior at the single fibril level, which has not been previously measured. PMID: 19878908 [PubMed - in process] (Source: Journal of the Mechanical Behavior of Biomedical Materials)
Source: Journal of the Mechanical Behavior of Biomedical Materials - November 3, 2009 Category: Materials Science Authors: Svensson RB, Hassenkam T, Hansen P, Peter Magnusson S Tags: J Mech Behav Biomed Mater Source Type: journals

Fracture of tooth enamel from incipient microstructural defects.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
We present definitive evidence for crack growth from internal defects called 'tufts' in human enamel. Transverse slices (normal to the tooth axis) sawn from extracted human teeth are embedded in a polycarbonate sandwich configuration and tested in simple flexural loading. The evolution of ensuing cracks across the enamel sections is viewed in situ by a video camera. The observations unequivocally identify tufts as sources of internal tooth fracture. In sufficiently thin slices the enamel becomes translucent, allowing for through-thickness observations of the crack topography. Crack segments that appear to be disjointed on ...
Source: Journal of the Mechanical Behavior of Biomedical Materials - November 3, 2009 Category: Materials Science Authors: Chai H, Lee JJ, Lawn BR Tags: J Mech Behav Biomed Mater Source Type: journals

Friction of F-actin knots.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
We use the existing data of force-extension experiments on F-actin molecules tied into knots to compute a value of 0.15 for the static friction coefficient for contact between different parts of the same molecule with itself. This estimate for protein-protein friction is relevant for the stabilization of the 273 known proteins with knots, one percent of the structures deposited in the Protein Data Bank. PMID: 19878910 [PubMed - in process] (Source: Journal of the Mechanical Behavior of Biomedical Materials)
Source: Journal of the Mechanical Behavior of Biomedical Materials - November 3, 2009 Category: Materials Science Authors: Kirchner HO, Neukirch S Tags: J Mech Behav Biomed Mater Source Type: journals

Transversely isotropic tensile material properties of skeletal muscle tissue.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Of the plethora of work performed analyzing skeletal muscle tissue, relatively little has been done in the examination of its passive material properties. Previous studies of the passive properties of skeletal muscle have been primarily performed along the longitudinal material direction. In order to ensure the accuracy of the predictions of computational models of skeletal muscles, a better understanding of the tensile three-dimensional material properties of muscle tissue is necessary. To that end, the purpose of this study was to collect a comprehensive set of tensile stress-strain data from skeletal muscle tissue. ...
Source: Journal of the Mechanical Behavior of Biomedical Materials - November 3, 2009 Category: Materials Science Authors: Morrow DA, Haut Donahue TL, Odegard GM, Kaufman KR Tags: J Mech Behav Biomed Mater Source Type: journals

A composite kidney stone phantom with mechanical properties controllable over the range of human kidney stones.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
A novel composite kidney stone phantom has been developed. This stone phantom is producible with mechanical properties mimicking the range of tensile fracture strength and acoustic properties of human kidney stones and is an inorganic/organic composite material, as are natural kidney stones. Diametral compression testing was used to measure tensile fracture strength, which determines the acoustic comminution behavior of kidney stones. Ultrasound transmission tests were made to characterize the acoustic properties of these stone phantoms. Both the tensile fracture strength (controllable from 1 to approximately 5 MPa) an...
Source: Journal of the Mechanical Behavior of Biomedical Materials - November 3, 2009 Category: Materials Science Authors: Simmons WN, Cocks FH, Zhong P, Preminger G Tags: J Mech Behav Biomed Mater Source Type: journals

4th TMS symposium on biological materials science.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
PMID: 19716100 [PubMed - in process] (Source: Journal of the Mechanical Behavior of Biomedical Materials)
Source: Journal of the Mechanical Behavior of Biomedical Materials - September 2, 2009 Category: Materials Science Authors: Roeder RK Tags: J Mech Behav Biomed Mater Source Type: journals

Nanomechanics of biocompatible TiO(2) nanotubes by Interfacial Force Microscopy (IFM).Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Titanium dioxide (TiO(2)) coatings exhibit desirable properties as biocompatible coatings. In this paper we report on mechanical properties and deformation behavior of (TiO(2)) nanotubes grown on pure titanium substrates through anodic oxidation. Characterization of the as-processed coatings was conducted using scanning electron microscopy (SEM). Nanoindentation, using Interfacial Force Microscopy (IFM), was employed to probe the Young's modulus of the nanotubes. Using the IFM technique, the modulus of the nanotube coating may be measured with minimal contribution from the underlying Ti substrate. The modulus of the (T...
Source: Journal of the Mechanical Behavior of Biomedical Materials - September 2, 2009 Category: Materials Science Authors: Crawford GA, Chawla N, Houston JE Tags: J Mech Behav Biomed Mater Source Type: journals

Hydrophilic-hydrophobic hydrogels for cartilage replacement.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
A new class of hydrogels combining both hydrophilic and hydrophobic structures are presented. Hydrogels have been investigated as cartilage replacement materials due to the high water content potentially leading to low friction, low wear, and rubbery or pliable nature similar to native cartilage. Unfortunately, many of these hydrogels lack the required shear, tear, and creep strength necessary to be used as cartilage replacement materials. The new hydrogels presented here utilize hydrophobic domains to reinforce the structure and provide higher tear, shear, and creep strengths versus traditional hydrogels without sacri...
Source: Journal of the Mechanical Behavior of Biomedical Materials - September 2, 2009 Category: Materials Science Authors: Thomas BH, Craig Fryman J, Liu K, Mason J Tags: J Mech Behav Biomed Mater Source Type: journals

Bio-inspired design of dental multilayers: experiments and model.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
This paper combines experiments, simulations and analytical modeling that are inspired by the stress reductions associated with the functionally graded structures of the dentin-enamel-junctions (DEJs) in natural teeth. Unlike conventional crown structures in which ceramic crowns are bonded to the bottom layer with an adhesive layer, real teeth do not have a distinct "adhesive layer" between the enamel and the dentin layers. Instead, there is a graded transition from enamel to dentin within a approximately 10 to 100 microm thick regime that is called the Dentin Enamel Junction (DEJ). In this paper, a micro-scale, bio-in...
Source: Journal of the Mechanical Behavior of Biomedical Materials - September 2, 2009 Category: Materials Science Authors: Niu X, Rahbar N, Farias S, Soboyejo W Tags: J Mech Behav Biomed Mater Source Type: journals

Statistical approach to the unfolding of mechanically stressed biopolymers.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The mechanical properties of structural biomaterials are determined by features at many length scales. One example is the presence of an organic adhesive in nacre. The organic material contains biopolymers with discrete domains that may unfold as the polymer is extended. A statistical model for the mechanical response of a single biopolymer with these characteristics is introduced and studied. The response to tensile strain under displacement-controlled and load-controlled conditions is examined. Under the assumption of irreversible unfolding, analytical expressions for the load at first unfolding were derived, and a t...
Source: Journal of the Mechanical Behavior of Biomedical Materials - September 2, 2009 Category: Materials Science Authors: Jhon MH, Chrzan DC Tags: J Mech Behav Biomed Mater Source Type: journals

Interfacial shear strength in abalone nacre.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The shear strength of the interface between tiles of aragonite in the nacre of red abalone Haliotis rufescens was investigated through mechanical tensile and shear tests. Dog-bone shaped samples were used to determine the tensile strength of nacre when loaded parallel to the plane of growth; the mean strength was 65 MPa. Shear tests were conducted on a special fixture with a shear gap of 200 microm, approximately 100 microm narrower than the spacing between mesolayers. The shear strength is found to be 36.9+/-15.8 MPa with an average maximum shear strain of 0.3. Assuming the majority of failure occurs through tile pull...
Source: Journal of the Mechanical Behavior of Biomedical Materials - September 2, 2009 Category: Materials Science Authors: Lin AY, Meyers MA Tags: J Mech Behav Biomed Mater Source Type: journals

Differences in the mechanical behavior of cortical bone between compression and tension when subjected to progressive loading.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The hierarchical arrangement of collagen and mineral into bone tissue presumably maximizes fracture resistance with respect to the predominant strain mode in bone. Thus, the ability of cortical bone to dissipate energy may differ between compression and tension for the same anatomical site. To test this notion, we subjected bone specimens from the anterior quadrant of human cadaveric tibiae to a progressive loading scheme in either uniaxial tension or uniaxial compression. One tension (dog-bone shape) and one compression specimen (cylindrical shape) were collected each from tibiae of nine middle aged male donors. At ea...
Source: Journal of the Mechanical Behavior of Biomedical Materials - September 2, 2009 Category: Materials Science Authors: Nyman JS, Leng H, Neil Dong X, Wang X Tags: J Mech Behav Biomed Mater Source Type: journals

Structure and mechanical properties of supercritical carbon dioxide processed porous resorbable polymer constructs.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Current bone graft substitute materials do not address the complex architectural and biomechanical requirements to achieve a successful spinal fusion. The development of porous, structural constructs for use in spinal fusion surgeries is thus an area of intense interest. Numerous techniques have been introduced to fabricate porous resorbable polymer constructs. However, these techniques have been associated with the use of potentially harmful organic solvents, and resulted in materials with less than optimal properties. Supercritical carbon dioxide (scCO(2)) processing appears to be a promising technique for producing ...
Source: Journal of the Mechanical Behavior of Biomedical Materials - September 2, 2009 Category: Materials Science Authors: Baker KC, Bellair R, Manitiu M, Herkowitz HN, Kannan RM Tags: J Mech Behav Biomed Mater Source Type: journals

Mechanical properties of hydroxyapatite whisker reinforced polyetherketoneketone composite scaffolds.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The apparent mechanical properties of hydroxyapatite (HA) whisker reinforced polyetherketoneketone (PEKK) scaffolds were evaluated in unconfined, uniaxial compression to investigate the effects of the porosity (75%, 82.5% and 90%), HA content (0, 20 and 40 vol%) and mold temperature (350, 365 and 375 ( composite function)C). Increased porosity resulted in a non-linear decrease in the elastic modulus and yield strength for both reinforced and unreinforced PEKK scaffolds, as expected. The increase in elastic modulus and yield strength with increased relative density followed a power-law, similar to trabecular bone and ot...
Source: Journal of the Mechanical Behavior of Biomedical Materials - September 2, 2009 Category: Materials Science Authors: Converse GL, Conrad TL, Roeder RK Tags: J Mech Behav Biomed Mater Source Type: journals

Special issue on nanoindentation of biological materials.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
PMID: 19627836 [PubMed - in process] (Source: Journal of the Mechanical Behavior of Biomedical Materials)
Source: Journal of the Mechanical Behavior of Biomedical Materials - July 27, 2009 Category: Materials Science Authors: Oyen M, Taylor D Tags: J Mech Behav Biomed Mater Source Type: journals

Surface detection errors cause overestimation of the modulus in nanoindentation on soft materials.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The accuracy of mechanical properties from depth-sensing indentation, or nanoindentation, depends on the accuracy of the displacement measurement used to calculate these properties. Here, current nanoindentation techniques and analysis methods for accurate displacement measurements are reviewed. First, the ability of a commercial instrument to sense the surface of soft materials is examined. Second, methods of sample surface detection are reviewed. Finally, a case of overestimation of the elastic modulus of a compliant material using nanoindentation with incorrect displacement values is presented. PMID: 19627837 [P...
Source: Journal of the Mechanical Behavior of Biomedical Materials - July 27, 2009 Category: Materials Science Authors: Kaufman JD, Klapperich CM Tags: J Mech Behav Biomed Mater Source Type: journals

Determination of viscoelastic-plastic material parameters of biomaterials by instrumented indentation.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Load response of viscoelastic-plastic materials depends on the load magnitude and history, and can be described by rheological models consisting of springs and dashpots. The parameters in these models can be obtained by instrumented indentation. Time-dependent properties are determined best from the time course of indenter displacement under constant load, but one must consider also the initial loading history. For characterization of instantaneous elastic and plastic response, fast loading and unloading are necessary. The paper summarizes the formulae for indentation into elastic-plastic and viscoelastic-plastic mater...
Source: Journal of the Mechanical Behavior of Biomedical Materials - July 27, 2009 Category: Materials Science Authors: Mencík J, He LH, Swain MV Tags: J Mech Behav Biomed Mater Source Type: journals

A fiber reinforced poroelastic model of nanoindentation of porcine costal cartilage: a combined experimental and finite element approach.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Nanoindentation has shown promise as a mechanical characterization tool for orthopaedic biomaterials since it can probe the properties of small, heterogeneous, irregularly shaped tissue volumes in physiological environments. However, the majority of nanoindentation analyses have been limited to the determination of linear elastic and viscoelastic properties. Since biomaterials possess complex nonlinear, hydrated, time-dependent constitutive behavior, the objective of the present study is to explore the ability of nanoindentation to determine physiologically relevant material properties using a fibril reinforced poroela...
Source: Journal of the Mechanical Behavior of Biomedical Materials - July 27, 2009 Category: Materials Science Authors: Gupta S, Lin J, Ashby P, Pruitt L Tags: J Mech Behav Biomed Mater Source Type: journals

Nanoindentation of the insertional zones of human meniscal attachments into underlying bone.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The objective of this study was to use nanoindentation to investigate the transition from meniscal attachment into underlying subchondral bone through uncalcified and calcified fibrocartilage. Nanoindentation tests were performed on both the anterior and posterior meniscal insertions to measure the instantaneous elastic modulus and elastic modulus at infinite time. The elastic moduli were found to increase in a bi-linear fashion from the external ligamentous attachment to the subchondral bone. The elastic moduli for the anterior attachments were consistently larger than those for the matching posterior attachments at simil...
Source: Journal of the Mechanical Behavior of Biomedical Materials - July 27, 2009 Category: Materials Science Authors: Hauch KN, Oyen ML, Odegard GM, Haut Donahue TL Tags: J Mech Behav Biomed Mater Source Type: journals

Effect of osteocalcin deficiency on the nanomechanics and chemistry of mouse bones.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In healthy bone there is a balance between bone resorption and formation. When an imbalance occurs there is an overall loss of bone mass leading to an increased risk of fracture. The deterioration is typically accompanied by changes in the non-collagenous proteins in the bone. Osteocalcin (OC) is the most abundant noncollageneous bone matrix protein and it is believed to play a role in bone formation and resorption. Nanoindentation and Raman microspectroscopy have been used to correlate the mechanical and chemical properties of cortical bone from femora of OC -/- (osteocalcin deficient) mice and their wild-type control...
Source: Journal of the Mechanical Behavior of Biomedical Materials - July 27, 2009 Category: Materials Science Authors: Kavukcuoglu NB, Patterson-Buckendahl P, Mann AB Tags: J Mech Behav Biomed Mater Source Type: journals

Mechanical characterization of soft viscoelastic gels via indentation and optimization-based inverse finite element analysis.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
This study was aimed at investigating the application of an inverse finite element analysis technique to identify material parameters of polymer gels via nanoindentation creep testing, optimization, and finite element simulation. Nanoindentation experiments were conducted using a rigid circular flat punch, and then simulated using the commercial software ABAQUS. The optimization (error minimization) procedure was integrated in the parameter determination process using a Matlab shell program, which makes this approach readily adaptable to other test geometries and material models. The finite element results compare well wit...
Source: Journal of the Mechanical Behavior of Biomedical Materials - July 27, 2009 Category: Materials Science Authors: Liu K, VanLandingham MR, Ovaert TC Tags: J Mech Behav Biomed Mater Source Type: journals

Deformation partitioning provides insight into elastic, plastic, and viscous contributions to bone material behavior.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The objective of this study was to apply deformation partitioning to explore the role of hydration, tissue type, and degree of mineralization in bone and calcified cartilage. Wet, ethanol-dehydrated, and PMMA-embedded equine cortical bone samples and PMMA-embedded human femoral head tissues were analyzed for contributions of elastic, plastic and viscous deformation to the overall nanoindentation response at each site. While the alteration of hydration state had little effect on any measure of deformation, unembedded tissues demonstrated significantly greater measures of resistance to plastic deformation than PMMA-embedded ...
Source: Journal of the Mechanical Behavior of Biomedical Materials - July 27, 2009 Category: Materials Science Authors: Ferguson VL Tags: J Mech Behav Biomed Mater Source Type: journals

Use of focused ion beam milling for investigating the mechanical properties of biological tissues: a study of human primary molars.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In this paper, the usefulness of the specimen shaping ability of focused ion beam (FIB) milling in the micrometer scale and the high force resolution of the nanoindentation technique are demonstrated on human primary teeth. Micro-cantilevers, with a triangular cross-section <5 microm in width and 10 microm in length, were produced within 50 microm of the dentin-enamel junction (DEJ) using FIB milling, and were point-loaded at their free ends at 20 microN/s until failure using a nanoindenter. The elastic modulus and flexural strength of such micro-samples of human enamel, and their variation with respect to prism ori...
Source: Journal of the Mechanical Behavior of Biomedical Materials - July 27, 2009 Category: Materials Science Authors: Chan YL, Ngan AH, King NM Tags: J Mech Behav Biomed Mater Source Type: journals

Indentation techniques for evaluating the fracture toughness of biomaterials and hard tissues.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Indentation techniques for assessing fracture toughness are attractive due to the simplicity and expediency of experiments, and because they potentially allow the characterization of both local and bulk fracture properties. Unfortunately, rarely have such techniques been proven to give accurate fracture toughness values. This is a concern, as such techniques are seeing increasing usage in the study of biomaterials and biological hard tissues. Four available indentation techniques are considered in the present article: the Vickers indentation fracture (VIF) test, the cube corner indentation fracture (CCIF) test, the Vic...
Source: Journal of the Mechanical Behavior of Biomedical Materials - July 27, 2009 Category: Materials Science Authors: Kruzic JJ, Kim DK, Koester KJ, Ritchie RO Tags: J Mech Behav Biomed Mater Source Type: journals

A practical guide for analysis of nanoindentation data.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Mechanical properties of biological materials are increasingly explored via nanoindentation testing. This paper reviews the modes of deformation found during indentation: elastic, plastic, viscous and fracture. A scheme is provided for ascertaining which deformation modes are active during a particular indentation test based on the load-displacement trace. Two behavior maps for indentation are presented, one in the viscous-elastic-plastic space, concerning homogeneous deformation, and one in the plastic versus brittle space, concerning the transition to fracture behavior when the threshold for cracking is exceeded. Bes...
Source: Journal of the Mechanical Behavior of Biomedical Materials - July 27, 2009 Category: Materials Science Authors: Oyen ML, Cook RF Tags: J Mech Behav Biomed Mater Source Type: journals

Lies, damned lies and case studies.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
PMID: 19627847 [PubMed - in process] (Source: Journal of the Mechanical Behavior of Biomedical Materials)
Source: Journal of the Mechanical Behavior of Biomedical Materials - July 27, 2009 Category: Materials Science Authors: Lee TC, Taylor D Tags: J Mech Behav Biomed Mater Source Type: journals

Dental implant induced bone remodeling and associated algorithms.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
This article provides an extensive review on the issues of mandibular and maxillary bone remodeling as a result of dental implantation. Following the success of remodeling-driven orthopedic design from the long bone community, substantial clinical/experimental data of implantation have been driving the development of corresponding remodeling laws and algorithms to various dental settings, of which it is believed to contain potential to significantly impact on futuristic dental implant design. In this paper, the published remodeling data is analyzed and different biomechanical remodeling stimuli are assessed. The establishe...
Source: Journal of the Mechanical Behavior of Biomedical Materials - July 27, 2009 Category: Materials Science Authors: Lin D, Li Q, Li W, Swain M Tags: J Mech Behav Biomed Mater Source Type: journals

Ultra high molecular weight polyethylene: mechanics, morphology, and clinical behavior.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Ultra high molecular weight polyethylene (UHMWPE) is a semicrystalline polymer that has been used for over four decades as a bearing surface in total joint replacements. The mechanical properties and wear properties of UHMWPE are of interest with respect to the in vivo performance of UHMWPE joint replacement components. The mechanical properties of the polymer are dependent on both its crystalline and amorphous phases. Altering either phase (i.e., changing overall crystallinity, crystalline morphology, or crosslinking the amorphous phase) can affect the mechanical behavior of the material. There is also evidence that t...
Source: Journal of the Mechanical Behavior of Biomedical Materials - July 27, 2009 Category: Materials Science Authors: Sobieraj MC, Rimnac CM Tags: J Mech Behav Biomed Mater Source Type: journals

Characterization and fatigue damage of plasma sprayed HAp top coat with Ti and HAp/Ti bond coat layers on commercially pure titanium substrate.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The surface of commercially pure Ti (cp-Ti) substrate was grit-blasted with Al(2)O(3) powders and then wet-blasted with HAp/Ti mixed powders at room temperature. Then plasma spraying with Ti powders or HAp/Ti mixed powders on the blasted surface was carried out to form a bond coat layer, denoted as T50 and T100 bond coat for the former and HT100 bond coat for the later. The HAp top coat was subsequently sprayed with 100 mum thickness. The XRD patterns showed that the as-sprayed HT100 bond coat layer was mainly composed of HAp with minor components of Ti and TiO(2). EDS analysis also showed there co-existed HAp and Ti w...
Source: Journal of the Mechanical Behavior of Biomedical Materials - July 27, 2009 Category: Materials Science Authors: Rakngarm A, Mutoh Y Tags: J Mech Behav Biomed Mater Source Type: journals

Effect of fiber shape on mechanical behavior of composite with elastoplastic matrix and SMA reinforcement.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In this paper, an equivalent three-phase micromechanical model of composite with an elasto- plastic matrix and shape memory alloy (SMA) reinforcement is developed. Compared with the traditional two-phase method, the interaction among the austenitic phase, the martensite phase and the matrix phase is considered. During applications of the model, the predicted curve shows good agreement with the experimental result. Most attention is given to the effect of fiber shape on the overall response of the composite and the residual stress. It is helpful to design an intelligent composite. PMID: 19627851 [PubMed - in process...
Source: Journal of the Mechanical Behavior of Biomedical Materials - July 27, 2009 Category: Materials Science Authors: Zhu Y, Dui G Tags: J Mech Behav Biomed Mater Source Type: journals

Calibration of a constitutive model for the post-yield behaviour of cortical bone.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In this work, the post-yield behaviour of cortical bone is investigated using finite element modelling, nanoindentation and atomic force microscopy. Based on recent investigations, it is proposed that, since pressure dependent deformation mechanisms may contribute to yielding in bone, constitutive models attempting to capture its post-yield behaviour should also incorporate pressure dependence. Nanoindentation testing is performed using a spheroconical indenter tip, and subsequent atomic force microscopy at the indented site shows that bone does not exhibit surface pile-up. By simulating the nanoindentation test, it is...
Source: Journal of the Mechanical Behavior of Biomedical Materials - July 27, 2009 Category: Materials Science Authors: Mullins LP, Bruzzi MS, McHugh PE Tags: J Mech Behav Biomed Mater Source Type: journals

Al2O3/GdAlO3 fiber for dental porcelain reinforcement.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In conclusion, the reinforcement of the porcelain with continuous fibers resulted in an efficient mechanism to increase its mechanical properties; however the addition of milled fibers had no significant effect on the material because the porcelain was not able to wet the ceramic particles during the firing cycle. PMID: 19627853 [PubMed - in process] (Source: Journal of the Mechanical Behavior of Biomedical Materials)
Source: Journal of the Mechanical Behavior of Biomedical Materials - July 27, 2009 Category: Materials Science Authors: Medeiros IS, Luz LA, Yoshimura HN, Cesar PF, Hernandes AC Tags: J Mech Behav Biomed Mater Source Type: journals

Fractography and fracture toughness of human dentin.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Dentin, the mineralized tissue forming the bulk of the tooth, serves as an energy-absorbing cushion for the hard, wear-resistant enamel and protects the inner soft tissues. Several studies used fracture mechanics methods to study the fracture toughness of dentin. However, all of them utilized precracks and cannot be used to estimate the intrinsic critical flaw size of dentin. We applied quantitative fractography to study the fracture pattern and fracture toughness of human dentin. Sixteen specimens were prepared from the coronal dentin and fractured in three-point flexure. Fracture surfaces were examined using a scanni...
Source: Journal of the Mechanical Behavior of Biomedical Materials - July 27, 2009 Category: Materials Science Authors: Yan J, Taskonak B, Mecholsky JJ Tags: J Mech Behav Biomed Mater Source Type: journals

Development and characterisation of an agar--polyvinyl alcohol blend hydrogel.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Numerous authors have reported on hydrogel technologies providing products suitable for applications in biomedical, personal care as well as in nano-sensor applications. Hydrogels fabricated from single polymers have been extensively investigated. However, in many cases a single polymer alone cannot meet divergent demands in terms of both properties and performance. In this work, hydrogels were prepared by physically blending the natural polymer agar with polyvinyl alcohol in varying ratios to produce a new biosynthetic polymer applicable for a variety of purposes. Hydrogen bonding was observed to take place between th...
Source: Journal of the Mechanical Behavior of Biomedical Materials - July 27, 2009 Category: Materials Science Authors: Lyons JG, Geever LM, Nugent MJ, Kennedy JE, Higginbotham CL Tags: J Mech Behav Biomed Mater Source Type: journals

Mechanical determinants of epithelium thickness in early-stage embryos.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
To address the fundamental question, "How is the thickness of an embryonic epithelium determined?" equations of force equilibrium are derived and used to construct a theory applicable to embryonic epithelia and other labile monolayers, including confluent cultured cells. Under typical physiological conditions, the underlying mathematical relationships can be reworked into one simple algebraic equation. The theory shows that sheet thickness is determined by mechanical interactions between microfilaments, microtubules, cell adhesion systems and in-plane loading. It also explains the perplexing negative in-plane Poisson's...
Source: Journal of the Mechanical Behavior of Biomedical Materials - July 27, 2009 Category: Materials Science Authors: Chen X, Brodland GW Tags: J Mech Behav Biomed Mater Source Type: journals

R-curve behavior and micromechanisms of fracture in resin based dental restorative composites.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The fracture properties and micromechanisms of fracture for two commercial dental composites, one microhybrid (FiltekZ250) and one nanofill (FiltekSupreme Plus), were studied by measuring fracture resistance curves (R-curves) using pre-cracked compact-tension specimens and by conducting both unnotched and double notched four point beam bending experiments. Four point bending experiments showed about 20% higher mean flexural strength of the microhybrid composite compared to the nanofill. Rising fracture resistance was observed over approximately 1 mm of crack extension for both composites, and higher overall fracture re...
Source: Journal of the Mechanical Behavior of Biomedical Materials - July 27, 2009 Category: Materials Science Authors: Shah MB, Ferracane JL, Kruzic JJ Tags: J Mech Behav Biomed Mater Source Type: journals

The effect of concentration, thermal history and cell seeding density on the initial mechanical properties of agarose hydrogels.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The objective of this study was to determine the influence of agarose concentration, the cooling rate during gelation, the thermal history following gelation and the cell seeding density on the initial mechanical properties of agarose hydrogels. The average ramp modulus of 2% agarose gel in tension was 24.9 kPa (+/-1.7, n=10), compared with 55.6 kPa (+/-0.5, n=10) in compression. The average tensile equilibrium modulus was 39.7 kPa (+/-5.7, n=6), significantly higher than the compressive equilibrium modulus of 14.2 kPa (+/-1.6, n=10). The equilibrium and dynamic compressive modulus of agarose hydrogels were observed to red...
Source: Journal of the Mechanical Behavior of Biomedical Materials - July 27, 2009 Category: Materials Science Authors: Buckley CT, Thorpe SD, O'Brien FJ, Robinson AJ, Kelly DJ Tags: J Mech Behav Biomed Mater Source Type: journals

Constitutive modeling of crimped collagen fibrils in soft tissues.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
A microstructurally oriented constitutive formulation for the hyperelastic response of crimped collagen fibrils existing in soft connective tissues is proposed. The model is based on observations that collagen fibrils embedded in a soft matrix crimp into a smooth three-dimensional pattern when unloaded. Following ideas presented by Beskos and Jenkins [Beskos, D., Jenkins, J., 1975. A mechanical model for mammalian tendon. ASME Journal of Applied Mechanics 42, 755-758] and Freed and Doehring [Freed, A., Doehring, T., 2005. Elastic model for crimped collagen fibrils. Journal of Biomechanical Engineering 127, 587-593] the...
Source: Journal of the Mechanical Behavior of Biomedical Materials - July 27, 2009 Category: Materials Science Authors: Grytz R, Meschke G Tags: J Mech Behav Biomed Mater Source Type: journals