Results From Demineralized Bone Creep Tests Suggest That Collagen Is Responsible for the Creep Behavior of Bone

1999 ◽  
Vol 121 (2) ◽  
pp. 253-258 ◽  
Author(s):  
S. M. Bowman ◽  
L. J. Gibson ◽  
W. C. Hayes ◽  
T. A. McMahon
Keyword(s):  
Trabecular Bone ◽  
Cortical Bone ◽  
Power Law ◽  
Creep Behavior ◽  
Damage Accumulation ◽  
Activation Energies ◽  
Analysis Of Covariance ◽  
Type I ◽  
Creep Tests ◽  
Demineralized Bone

Cortical and trabecular bone have similar creep behaviors that have been described by power-law relationships, with increases in temperature resulting in faster creep damage accumulation according to the usual Arrhenius (damage rate ~ exp (−Temp.−1)) relationship. In an attempt to determine the phase (collagen or hydroxyapatite) responsible for these similar creep behaviors, we investigated the creep behavior of demineralized cortical bone, recognizing that the organic (i.e., demineralized) matrix of both cortical and trabecular bone is composed primarily of type I collagen. We prepared waisted specimens of bovine cortical bone and demineralized them according to an established protocol. Creep tests were conducted on 18 specimens at various normalized stresses σ/E0 and temperatures using a noninvasive optical technique to measure strain. Denaturation tests were also conducted to investigate the effect of temperature on the structure of demineralized bone. The creep behavior was characterized by the three classical stages of decreasing, constant, and increasing creep rates at all applied normalized stresses and temperatures. Strong (r2 > 0.79) and significant (p < 0.01) power-law relationships were found between the damage accumulation parameters (steady-state creep rate dε/dt and time-to-failure tf) and the applied normalized stress σ/E0. The creep behavior was also a function of temperature, following an Arrhenius creep relationship with an activation energy Q = 113 kJ/mole, within the range of activation energies for cortical (44 kJ/ mole) and trabecular (136 kJ/mole) bone. The denaturation behavior was characterized by axial shrinkage at temperatures greater than approximately 56°C. Lastly, an analysis of covariance (ANCOVA) of our demineralized cortical bone regressions with those found in the literature for cortical and trabecular bone indicates that all three tissues creep with the same power-law exponents. These similar creep activation energies and exponents suggest that collagen is the phase responsible for creep in bone.

scholarly journals Hypergravity as a gravitational therapy mitigates the effects of knee osteoarthritis on the musculoskeletal system in a murine model

PLoS ONE ◽  
2020 ◽  
Vol 15 (12) ◽  
pp. e0243098
Author(s):  
Benoit Dechaumet ◽  
Damien Cleret ◽  
Marie-Thérèse Linossier ◽  
Arnaud Vanden-Bossche ◽  
Stéphanie Chanon ◽  
...  
Keyword(s):  
Trabecular Bone ◽  
Cortical Bone ◽  
Musculoskeletal System ◽  
Tibialis Anterior ◽  
Lipid Droplets ◽  
Proximal Tibia ◽  
Type I ◽  
Negative Effects ◽  
Positive Effects ◽  
Resistance Exercises

Insights into the effects of osteoarthritis (OA) and physical interventions on the musculoskeletal system are limited. Our goal was to analyze musculoskeletal changes in OA mice and test the efficacy of 8-week exposure to hypergravity, as a replacement of physical activity. 16-week-old male (C57BL/6J) mice allocated to sham control and OA groups not centrifuged (Ctrl 1g and OA 1g, respectively) or centrifuged at 2g acceleration (Ctrl 2g and OA 2g). OA 1g displayed decreased trabecular bone in the proximal tibia metaphysis and increased osteoclastic activity and local TNFα gene expression, all entirely prevented by 2g gravitational therapy. However, while cortical bone of tibia midshaft was preserved in OA 1g (vs. ctrl), it is thinner in OA 2g (vs. OA 1g). In the hind limb, OA at 1g increased fibers with lipid droplets by 48% in the tibialis anterior, a fact fully prevented by 2g. In Ctrl, 2g increased soleus, tibialis anterior and gastrocnemius masses. In the soleus of both Ctrl and OA, 2g induced larger fibers and a switch from type-II to type-I fiber. Catabolic (myostatin and its receptor activin RIIb and visfatine) and anabolic (FNDC5) genes dramatically increased in Ctrl 2g and OA 2g (p<0.01 vs 1g). Nevertheless, the overexpression of FNDC5 (and follistatine) was smaller in OA 2g than in Ctrl 2g. Thus, hypergravity in OA mice produced positive effects for trabecular bone and muscle typology, similar to resistance exercises, but negative effects for cortical bone.

scholarly journals Enhancement of the adolescent murine musculoskeletal system using low-level mechanical vibrations

2008 ◽  
Vol 104 (4) ◽  
pp. 1056-1062 ◽  
Author(s):  
Liqin Xie ◽  
Clinton Rubin ◽  
Stefan Judex
Keyword(s):  
Trabecular Bone ◽  
Cortical Bone ◽  
Musculoskeletal System ◽  
Structural Changes ◽  
Whole Body ◽  
Type I ◽  
Mechanical Stimuli ◽  
Bone Area ◽  
Cross Sectional ◽  
Small Magnitude

Mechanical signals are recognized as anabolic to both bone and muscle, but the specific parameters that are critical to this stimulus remain unknown. Here we examined the potential of extremely low-magnitude, high-frequency mechanical stimuli to enhance the quality of the adolescent musculoskeletal system. Eight-week-old female BALB/cByJ mice were divided into three groups: baseline controls (BC, n = 8), age-matched controls (AC, n = 12), and whole body vibration (WBV, n = 12) at 45 Hz (0.3 g) for 15 min/day. Following 6 wk of WBV, bone mineralizing surfaces of trabeculae in the proximal metaphysis of the tibia were 75% greater ( P < 0.05) than AC, while osteoclast activity was not significantly different. The tibial metaphysis of WBV mice had 14% greater trabecular bone volume ( P < 0.05) than AC, while periosteal bone area, bone marrow area, cortical bone area, and the moments of inertia of this region were all significantly greater (up to 29%, P < 0.05). The soleus muscle also realized gains by WBV, with total cross-sectional area as well as type I and type II fiber area as much as 29% greater ( P < 0.05) in mice that received the vibratory mechanical stimulus. The small magnitude and brief application of the noninvasive intervention emphasize that the mechanosensitive elements of the musculoskeletal system are not necessarily dependent on strenuous, long-term activity to initiate a structurally relevant response in the adolescent musculoskeletal system. If maintained into adulthood, the beneficial structural changes in trabecular bone, cortical bone, and muscle may serve to decrease the incidence of osteoporotic fractures and sarcopenia later in life.

Creep Behavior and Microstructural Stability of Ti-46Al-9Nb with Different Microstructures

2004 ◽  
Vol 842 ◽  
Author(s):  
S. Bystrzanowski ◽  
A. Bartels ◽  
H. Clemens ◽  
R. Gerling ◽  
F.-P. Schimansky ◽  
...  
Keyword(s):  
Creep Behavior ◽  
Sheet Material ◽  
Lamellar Microstructure ◽  
Lamellar Spacing ◽  
Activation Energies ◽  
Microstructural Stability ◽  
X Ray Diffraction ◽  
Creep Tests ◽  
Apparent Activation Energies ◽  
Term Creep

ABSTRACTIn this paper the creep behavior and the microstructural stability of Ti-46Al-9Nb (in at.%) sheet material were investigated in the temperature range of 700°C to 815°C. The study involves three different types of microstructure, namely fully lamellar with narrow lamellar spacing, duplex and massively transformed. Short-term creep experiments conducted at 700°C and 225 MPa confirmed that the lamellar microstructure with narrow lamellar spacing exhibits a much higher creep resistance when compared to the massively transformed and duplex ones. During longterm creep tests up to 1500 hours stress exponents (in the range of 4.4 to 5.8) and apparent activation energies (of about 4 eV) have been estimated by means of load and temperature changes, respectively. Both, stress exponents and activation energies suggest that under the applied conditions diffusion-assisted climb of dislocations is the dominant creep mechanism. The thermal stability of the different microstructures under various creep conditions has been analyzed by electron microscopy and X-ray diffraction. Our investigations revealed considerable stress and temperature induced microstructural changes which are reflected in the dissolution of the α2 phase accompanied by precipitation of a Ti/Nb - rich phase situated at grain boundaries. This phase was identified as a ω-related phase with B82-type structure. It was shown, that in particular the duplex microstructure is prone to such microstructural instabilities.

scholarly journals Interleukin (IL)-10 Is Important in the Maintenance of Trabecular and Cortical Bone and Protects Against Western Diet-Induced Disruption in Bone Remodeling in Mice

2021 ◽  
Vol 5 (Supplement_2) ◽  
pp. 1137-1137
Author(s):  
Leo Perez ◽  
Sanmi Alake ◽  
Payton Price ◽  
Proapa Islam ◽  
John Ice ◽  
...  
Keyword(s):  
Body Weight ◽  
Trabecular Bone ◽  
Bone Metabolism ◽  
Cortical Bone ◽  
Structural Changes ◽  
Western Diet ◽  
Whole Body ◽  
Strain Effect ◽  
Type I ◽  
X Ray

Abstract Objectives The purpose of this study was to investigate if consumption of a western diet (WD) exacerbates the effects of loss of function of IL-10, an anti-inflammatory cytokine, on biomarkers of bone metabolism and microarchitecture. Methods Six-week-old male B6.129P2-Il10tm1Cgn/J (IL-10 KO) and C57BL/6 mice (WT) were randomized to treatment in a 2 × 2 factorial with diet (AIN-93 control diet CD vs WD) and strain (IL-10 KO vs WT) as factors. Due to potential influence of high fat on intestinal Ca absorption, a WD diet with added Ca (1.2 g/kg) was used. After 12 wks, whole body dual-energy x-ray absorptiometry scans were performed to assess bone density and body composition, and micro-computed x-ray tomography was used to evaluate trabecular and cortical bone microarchitecture in the femur and lumbar vertebra. Serum biomarkers of bone formation, procollagen 1 intact N-terminal propeptide (P1NP), and resorption, c-terminal telopeptide of type I collagen (CTX-1) were assessed. Results Body weight, but not % body fat, was lower (P &lt; 0.05) in IL-10 KO mice relative to WT controls. 12 weeks of WD increased (P &lt; 0.05) body weight and % fat, but the response was not as great in the IL-10 KO mice. Bone mineral density and content were lower in IL-10 KO mice compared to WT, and the WD had no effect on these parameters. The IL-10 KO mice exhibited a decrease in trabecular bone volume, thickness, and number, and an increase in trabecular separation and structure model index compared to WT mice within the femur and vertebrae. The WD had no effect on these trabecular bone parameters. Cortical bone thickness and area were reduced (P &lt; 0.05) and porosity increased in both the femur and vertebra of IL-10 KO mice relative to their WT counterparts. This strain effect was not altered by the WD. IL-10 KO mice exhibited a significantly lower serum PINP and higher CTX-1 compared to the WT mice. Despite the lack of structural changes in bone after 12 wks, the WD increased (P &lt; 0.05) CTX-1 and tended to suppress P1NP (P = 0.051) in the IL-10 KO mice compared to WT. Conclusions We conclude that IL-10 plays an important role in bone metabolism and maintaining structural properties and in the absence of IL-10, WD negatively affects both osteoclast and osteoblast activity. Further studies are warranted to determine if structural changes occur with longer exposure to WD. Funding Sources Oklahoma Agricultural Experiment Station.

scholarly journals POS1092 SUBCHONDRAL BONE NORMALIZATION AFTER KNEE JOINT DISTRACTION TREATMENT AS MEASURED WITH CT

2021 ◽  
Vol 80 (Suppl 1) ◽  
pp. 825.2-826
Author(s):  
M. Jansen ◽  
A. Ooms ◽  
T. D. Turmezei ◽  
J. W. Mackay ◽  
S. Mastbergen ◽  
...  
Keyword(s):  
Bone Density ◽  
Trabecular Bone ◽  
Cortical Bone ◽  
Subchondral Bone ◽  
Trabecular Bone Density ◽  
Bone Thickness ◽  
Cortical Bone Thickness ◽  
Bone Changes ◽  
One Year ◽  
Shape Changes

Background:In addition to cartilage degeneration, knee osteoarthritis (OA) causes bone changes, including cortical bone thickening, subchondral bone density decrease, and bone shape changes as a result of widening and flattening condyles and osteophyte formation. Knee joint distraction (KJD) is a joint-preserving treatment for younger (<65 years) knee OA patients that has been shown to reverse OA cartilage degradation. On radiographs, KJD showed a decrease in subchondral bone density and an increase in osteophyte formation. However, these bone changes have never been evaluated with a 3D imaging technique.Objectives:To evaluate cortical bone thickness, subchondral trabecular bone density, and bone shape on CT scans before and one year after KJD treatment.Methods:19 KJD patients were included in an extended imaging protocol, undergoing a CT scan before and one year after treatment. Stradview v6.0 was used for semi-automatic tibia and femur segmentation from axial thin-slice (0.45mm) CT scans. Cortical bone thickness (mm) and trabecular bone density (Hounsfield units, HU) were measured with an automated algorithm. Osteophytes were excluded. Afterwards, wxRegSurf v18 was used for surface registration. Registration data was used for bone shape measurements. MATLAB R2020a and the SurfStat MATLAB package were used for data analysis and visualization. Two-tailed F-tests were used to calculate changes over time. Two separate linear regression models were used to show the influence of baseline Kellgren-Lawrence grade and sex on the changes over time. Statistical significance was calculated with statistical parametric mapping; a p-value <0.05 was considered statistically significant. Bone shape changes were explored visually using vertex by vertex displacements between baseline and follow-up. Patients were separated into two groups based on whether their most affected compartment (MAC) was medial or lateral. Only patients with axial CT scans at both time points available for analysis were included for evaluation.Results:3 Patients did not have complete CTs and in 1 patient the imaged femur was too short, leaving 16 patients for tibial analyses and 15 patients for femoral analyses. The MAC was predominantly the medial side (medial MAC n=14; lateral n=2). Before treatment, the MAC cortical bone was compared to the rest of the joint (Figure 1). One year after treatment, MAC cortical thickness decreased, although this decrease of up to approximately 0.25 mm was not statistically significant. The trabecular bone density was also higher before treatment in the MAC, and a decrease was seen throughout the entire joint, although statistically significant only for small areas on mostly the MAC where this decrease was up to approximately 80 HU (Figure 1). Female patients and patients with a higher Kellgren-Lawrence grade showed a somewhat larger decrease in cortical bone thickness. Trabecular density decreased less for patients with a higher Kellgren-Lawrence grade, and female patients showed a higher density decrease interiorly while male patients showed a higher decrease exteriorly. None of this was statistically significant. The central areas of both compartments showed an outward shape change, while the outer ring showed inward changes.Conclusion:MAC cortical bone thickness shows a partial decrease after KJD. Trabecular bone density decreased on both sides of the joint, likely as a direct result of the bicompartmental unloading. For both subchondral bone parameters, MAC values became more similar to the LAC, indicating (partial) subchondral bone normalization in the most affected parts of the joint. The bone shape changes may indicate a reversal of typical OA changes, although the inward difference that was seen on the outer edges may be a result of osteophyte-related changes that might have affected the bone segmentation. In conclusion, KJD treatment shows subchondral bone normalization in the first year after treatment, and longer follow-up might show whether these changes are a temporary result of joint unloading or indicate more prolonged bone changes.Disclosure of Interests:None declared.

Statistical analysis of creep behavior in thermoset and thermoplastic composites reinforced with carbon and glass fibers

2020 ◽  
pp. 030932472097663
Author(s):  
Francisco Maciel Monticeli ◽  
Ana Karoline dos Reis ◽  
Roberta Motta Neves ◽  
Luis Felipe de Paula Santos ◽  
Edson Cocchieri Botelho ◽  
...  
Keyword(s):  
Creep Behavior ◽  
Glass Fibers ◽  
Laminated Composite ◽  
Analytical Models ◽  
Thermoplastic Composites ◽  
Temperature Dependent ◽  
Creep Tests ◽  
Thermoset Composites ◽  
Strain Behavior ◽  
Sensitivity Range

The thermoplastic and thermoset laminates reinforced with different fibers generate variations in the laminated composite mechanical behavior. This work aims to analyze thermoplastic and thermoset composites creep behavior with a reduced number of experiments, applying curve-fitting analytical models (Weibull and Findley) and statistical approach (ANOVA, F-test, and SRM) in order to describe creep behavior. Creep tests were carried out using a design of experiments to define parameter levels, aiming to reduce the number of the experiments, keeping reliability relevance. The temperature shows a stronger influence of creep deformation compared with the use of distinct materials. Thermoplastic matrices seem to be more sensitive to deformation, decreasing the reinforcement contribution. On the other hand, the creep resistance of the thermoset matrix conducts a significant contribution of strain behavior for the reinforcement used. The Findley model showed a temperature-dependent response. While, the Weibull-based model exhibits temperature and material-dependence, ensuring a greater sensitivity range of the parameters applied, an essential factor for a more realistic method description.

Preoperative and Postoperative Voice in Tis-T1 Glottic Cancer Treated by Endoscopic Cordectomy: An Additional Issue for Patient Counseling

2003 ◽  
Vol 112 (9) ◽  
pp. 759-763 ◽  
Author(s):  
Giorgio Peretti ◽  
Maria C. Mensi ◽  
Cesare Piazza ◽  
Manuela Rossini ◽  
Cristiano Balzanelli ◽  
...  
Keyword(s):  
Analysis Of Covariance ◽  
Glottic Cancer ◽  
Type I ◽  
Patient Counseling ◽  
Subjective Data ◽  
Type Iii ◽  
Voice Changes ◽  
Index Evaluation ◽  
European Laryngological Society ◽  
The Voice

Radiotherapy contends with endoscopic surgery for the role of treatment of choice for Tis-T1 glottic cancer. The amount of vocal cord to be surgically removed logically depends on the surface and deep extension of the neoplasm. Thus, a prerequisite for proper management includes an analysis of the voice changes after each of the progressive types of cordectomy described in the European Laryngological Society Classification. Between January 1998 and December 2000, 89 patients with glottic cancer (8 Tis, 63 T1a, 18 T1b) underwent different types of endoscopic cordectomy. Perceptual analysis (GRBAS scale); objective analyses of jitter, shimmer, and noise-to-harmonics ratio; and subjective (Voice Handicap Index) evaluation of voice were performed in 51 patients. Statistical evaluation of preoperative and postoperative objective results by analysis of covariance, as well as perceptual and subjective data, showed significant voice improvement after type I and II cordectomies, with the voice attaining nearly normal parameters. By contrast, after type III, IV, and V cordectomies, the vocal outcome was not significantly different from the preoperative pattern. It can therefore be concluded that type I and II resections, whenever indicated, are adequate procedures even for professional voice users. By contrast, accurate counseling is mandatory before type III, IV, and V cordectomies.

An Experimental Study on the Effect of Prior Plastic Straining on Creep Behavior of 304 Stainless Steel

1993 ◽  
Vol 115 (2) ◽  
pp. 200-203 ◽  
Author(s):  
Z. Xia ◽  
F. Ellyin
Keyword(s):  
Stainless Steel ◽  
Plastic Strain ◽  
Strain Rate ◽  
Creep Behavior ◽  
Test Procedure ◽  
Constant Strain Rate ◽  
304 Stainless Steel ◽  
Creep Model ◽  
Plastic Strain Rate ◽  
Creep Tests

Constant strain-rate plastic straining followed by creep tests were conducted to investigate the effect of prior plastic straining on the subsequent creep behavior of 304 stainless steel at room temperature. The effects of plastic strain and plastic strain-rate were delineated by a specially designed test procedure, and it is found that both factors have a strong influence on the subsequent creep deformation. A creep model combining the two factors is then developed. The predictions of the model are in good agreement with the test results.

Tissue Engineering of Bone by Osteoinductive Biomaterials

MRS Bulletin ◽  
1996 ◽  
Vol 21 (11) ◽  
pp. 36-39 ◽  
Author(s):  
Ugo Ripamonti ◽  
Nicolaas Duneas
Keyword(s):  
Tissue Engineering ◽  
Bone Formation ◽  
Type I Collagen ◽  
Demineralized Bone Matrix ◽  
Bone Matrix ◽  
Mesenchymal Cells ◽  
Tissue Response ◽  
Type I ◽  
New Bone Formation ◽  
Demineralized Bone

Recent advances in materials science and biotechnology have given birth to the new and exciting field of tissue engineering, in which the two normally disparate fields are merging into a profitable matrimony. In particular the use of biomaterials capable of initiating new bone formation via a process called osteoinduction is leading to quantum leaps for the tissue engineering of bone.The classic work of Marshall R. Urist and A. Hari Reddi opened the field of osteoinductive biomaterials. Urist discovered that, upon implantation of devitalized, demineralized bone matrix in the muscle of experimental animals, new bone formation occurs within two weeks, a phenomenon he described as bone formation by induction. The tissue response elicited by implantation of demineralized bone matrix in muscle or under the skin includes activation and migration of undifferentiated mesenchymal cells by chemotaxis, anchoragedependent cell attachment to the matrix, mitosis and proliferation of mesenchymal cells, differentiation of cartilage, mineralization of the cartilage, vascular invasion of the cartilage, differentiation of osteoblasts and deposition of bone matrix, and finally mineralization of bone and differentiation of marrow in the newly developed ossicle.The osteoinductive ability of the extracellular matrix of bone is abolished by the dissociative extraction of the demineralized matrix, but is recovered when the extracted component, itself inactive, is reconstituted with the inactive residue—mainly insoluble collagenous bone matrix. This important experiment showed that the osteoinductive signal resides in the solubilized component but needs to be reconstituted with an appropriate carrier to restore the osteoinductive activity. In this case, the carrier is the insoluble collagenous bone matrix—mainly crosslinked type I collagen.

Trends in Trabecular and Cortical Bone in the Radius Compared with Whole Body Calcium Balance in Osteoporosis

1984 ◽  
Vol 66 (1) ◽  
pp. 109-112 ◽  
Author(s):  
R. Hesp ◽  
A. C. Deacon ◽  
Patricia Hulme ◽  
J. Reeve
Keyword(s):  
Trabecular Bone ◽  
Cortical Bone ◽  
Distal Radius ◽  
Rate Of Change ◽  
Whole Body ◽  
Calcium Balance ◽  
Total Absorption ◽  
Balance Study ◽  
Attenuation Coefficients ◽  
Change Trend

1. Mean linear attenuation coefficients for trabecular bone (T) in the distal radius and total absorption coefficients (TA) in the radial mid-shafts of 22 patients with crush fracture osteoporosis were measured serially for a year by using computed tomography. After approximately 6 months, each patient was admitted to a metabolic ward for an 18-day calcium balance study. 2. The rate of change (trend) in trabecular bone (T) in the distal radius was a better predictor of calcium balance than the trend in mid-shaft cortical bone (TA). 3. The scatter in the regressions of the trends of T and TA on calcium balance could be accounted for by known methodological uncertainties.

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