Dynamic mechanical response of polyvinyl alcohol-gelatin theta-gels for nucleus pulposus tissue replacement

2017 ◽  
Vol 12 (2) ◽  
pp. 02C409 ◽  
Author(s):  
Patrick N. Charron ◽  
Sarah E. Blatt ◽  
Canaan McKenzie ◽  
Rachael A. Oldinski
Author(s):  
Jacopo Fiocchi ◽  
Chiara Bregoli ◽  
Giulio Gerosa ◽  
Ausonio Tuissi ◽  
Carlo Alberto Biffi

1994 ◽  
Vol 27 (6) ◽  
pp. 826
Author(s):  
C.A. Brown ◽  
H.C. Ward ◽  
C.F. Abrams ◽  
S.C. Roe ◽  
D.J. Deyoung ◽  
...  

2010 ◽  
Vol 150-151 ◽  
pp. 1413-1416 ◽  
Author(s):  
Hong Yan Chen ◽  
Zhen Xing Kong ◽  
Ji Hui Wang

The cure kinetics of Derakane 411-350, a kind of vinyl ester resin, and its suspensions containing multi-walled carbon nanotubes( MWCNTs) were investigated via non-isothermal dynamic scanning calorimetry (DSC) measurements. The results showed that incorporation of MWCNTs into vinyl ester resin excessively reduces polymerization degree and crosslinking density of vinyl ester resin. For suppressing the negative effect caused by nanotubes, the higher temperature initiator combined with the initiator MEKP was used. Dynamic-mechanical Behavior testing was then carried out on the cured sample in order to relate the curing behavior of MWCNTs modified resin suspensions to mechanical response of their resulting nanocomposites. It was revealed that nanocomposites containing MWCNTs possessed larger storage modulus values as well as higher glass transition temperatures (Tg) as compared to those without MWCNTs after using mixed intiators system to improve the degree of cure.


2010 ◽  
Vol 163-167 ◽  
pp. 1645-1650
Author(s):  
Guo Ping Qian ◽  
Shuai Li ◽  
Li Jun Jiang

Under the heavy traffic, the stress state of asphalt pavement structure has such a complex change that it is difficult for conventional pavement structural response calculation model to deal with. Therefore, "Pavement structure dynamic mechanical response model under complex stress condition" is established in this paper. Kinds of cases are calculated according to the characteristics of heavy vehicle. Then the FWD deflection test and dynamic strain test are carried out. Finally, the rationality of pavement structural response model calculation model is proved by comparing the test results with the theoretical model calculation results.


2005 ◽  
Vol 127 (7) ◽  
pp. 1158-1167 ◽  
Author(s):  
Adam H. Hsieh ◽  
Diane R. Wagner ◽  
Louis Y. Cheng ◽  
Jeffrey C. Lotz

In vivo rodent tail models are becoming more widely used for exploring the role of mechanical loading on the initiation and progression of intervertebral disc degeneration. Historically, finite element models (FEMs) have been useful for predicting disc mechanics in humans. However, differences in geometry and tissue properties may limit the predictive utility of these models for rodent discs. Clearly, models that are specific for rodent tail discs and accurately simulate the disc’s transient mechanical behavior would serve as important tools for clarifying disc mechanics in these animal models. An FEM was developed based on the structure, geometry, and scale of the mouse tail disc. Importantly, two sources of time-dependent mechanical behavior were incorporated: viscoelasticity of the matrix, and fluid permeation. In addition, a novel strain-dependent swelling pressure was implemented through the introduction of a dilatational stress in nuclear elements. The model was then validated against data from quasi-static tension-compression and compressive creep experiments performed previously using mouse tail discs. Finally, sensitivity analyses were performed in which material parameters of each disc subregion were individually varied. During disc compression, matrix consolidation was observed to occur preferentially at the periphery of the nucleus pulposus. Sensitivity analyses revealed that disc mechanics was greatly influenced by changes in nucleus pulposus material properties, but rather insensitive to variations in any of the endplate properties. Moreover, three key features of the model—nuclear swelling pressure, lamellar collagen viscoelasticity, and interstitial fluid permeation—were found to be critical for accurate simulation of disc mechanics. In particular, collagen viscoelasticity dominated the transient behavior of the disc during the initial 2200s of creep loading, while fluid permeation governed disc deformation thereafter. The FEM developed in this study exhibited excellent agreement with transient creep behavior of intact mouse tail motion segments. Notably, the model was able to produce spatial variations in nucleus pulposus matrix consolidation that are consistent with previous observations in nuclear cell morphology made in mouse discs using confocal microscopy. Results of this study emphasize the need for including nucleus swelling pressure, collagen viscoelasticity, and fluid permeation when simulating transient changes in matrix and fluid stress/strain. Sensitivity analyses suggest that further characterization of nucleus pulposus material properties should be pursued, due to its significance in steady-state and transient disc mechanical response.


2019 ◽  
Vol 745 ◽  
pp. 279-290 ◽  
Author(s):  
Behnam Shakerifard ◽  
Jesus Galan Lopez ◽  
Mari Carmen Taboada Legaza ◽  
Patricia Verleysen ◽  
Leo A.I. Kestens

2016 ◽  
Vol 35 (1) ◽  
pp. 41-50 ◽  
Author(s):  
Rahul Gawri ◽  
Toshikazu Shiba ◽  
Robert Pilliar ◽  
Rita Kandel

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