Response of the Intervertebral Disk of the Rhesus Monkey to P-A Shear Stress

1980 ◽  
Vol 102 (2) ◽  
pp. 137-140 ◽  
Author(s):  
S. A. Lantz ◽  
J. F. Lafferty ◽  
D. A. Bowman
Keyword(s):  
Shear Stress ◽  
Rhesus Monkey ◽  
Nucleus Pulposus ◽  
Intervertebral Disk ◽  
Stress Strain ◽  
As Stress

The relative functions of spinal elements in resisting P-A shear stress are determined from measurements of force and displacement. The response of intact, enucleate and degenerate disks are presented, as well as stress-strain characteristics of the intervertebral disk and the roles of the articular facets and the nucleus pulposus.

Rhesus Monkey Intervertebral Disk Viscoelastic Response to Shear Stress

1983 ◽  
Vol 105 (1) ◽  
pp. 51-54 ◽  
Author(s):  
B. S. Kelley ◽  
J. F. Lafferty ◽  
D. A. Bowman ◽  
P. A. Clark
Keyword(s):  
Shear Stress ◽  
Rhesus Monkey ◽  
Material Properties ◽  
Mechanical Model ◽  
Viscoelastic Model ◽  
Intervertebral Disk ◽  
Viscoelastic Response ◽  
Relaxation Functions ◽  
Experimental Strain

A viscoelastic model of the shear response of the Rhesus monkey intervertebral disk, represented by a series chain of four Kelvin units is presented. Two types of investigations are carried out to assess the validity of the model: 1) determination of material properties by comparison with experimental strain creep behavior of the disk; and 2) validation of this viscoelastic model by accurately predicting the experimental results of stress relaxation tests. The use of the series Kelvin units approach provides the first analytical mechanical model capable of predicting the creep and relaxation functions for the intervertebral disk in shear.

scholarly journals Raloxifene retards the progression of adjacent segmental intervertebral disc degeneration by inhibiting apoptosis of nucleus pulposus in ovariectomized rats

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Qi Sun ◽  
Xin-Yu Nan ◽  
Fa-Ming Tian ◽  
Fang Liu ◽  
Shao-Hua Ping ◽  
...  
Keyword(s):  
Nucleus Pulposus ◽  
Lumbar Fusion ◽  
B Cell Lymphoma ◽  
Intervertebral Disk ◽  
Ovariectomized Rats ◽  
Tunel Staining ◽  
Mineral Density ◽  
Vertebral Osteoporosis ◽  
Intervertebral Disk Degeneration ◽  
Disk Degeneration

Abstract Background Adjacent segmental intervertebral disk degeneration (ASDD) is a major complication secondary to lumbar fusion. Although ASSD pathogenesis remains unclear, the primary cause of intervertebral disk degeneration (IVDD) development is apoptosis of nucleus pulposus (NP). Raloxifene (RAL) could delay ASDD by inhibiting NP apoptosis. Methods An ASDD rat model was established by ovariectomy (OVX) and posterolateral spinal fusion (PLF) on levels 4–5 of the lumbar vertebrae. Rats in the treatment groups were administered 1 mg/kg/d RAL by gavage for 12 weeks, following which, all animals were euthanized. Lumbar fusion, apoptosis, ASDD, and vertebrae micro-architecture were evaluated. Results RAL maintained intervertebral disk height (DHI), delayed vertebral osteoporosis, reduced histological score, and inhibited apoptosis. The OVX+PLF+RAL group revealed upregulated expression of aggrecan and B-cell lymphoma-2 (bcl2), as well as significantly downregulated expression of a disintegrin and metalloproteinase with thrombospondin motifs 4 (ADAMTS-4), metalloproteinase-13 (MMP-13), caspase-3, BCL2-associated X (bax), and transferase dUTP nick end labeling (TUNEL) staining. Micro-computed tomography (Micro-CT) analysis revealed higher bone volume fraction (BV/TV), bone mineral density (BMD), and trabecular number (Tb.N), and lower trabecular separation (Tb.Sp) in OVX+PLF+RAL group than in the OVX+PLF group. Conclusions RAL can postpone ASDD development in OVX rats through inhibiting extracellular matrix metabolic imbalance, NP cell apoptosis, and vertebral osteoporosis. These findings showed RAL as a potential therapeutic target for ASDD.

scholarly journals Human Bone Marrow Mesenchymal Stromal Cell-Derived Extracellular Vesicles Promote Proliferation of Degenerated Nucleus Pulposus Cells and the Synthesis of Extracellular Matrix Through the SOX4/Wnt/β-Catenin Axis

2021 ◽  
Vol 12 ◽  
Author(s):  
Haoyu Wang ◽  
Fei Li ◽  
Wenrui Ban ◽  
Jing Zhang ◽  
Guiqi Zhang
Keyword(s):  
Extracellular Matrix ◽  
Nucleus Pulposus ◽  
Extracellular Vesicles ◽  
Target Genes ◽  
Intervertebral Disk ◽  
Human Bone ◽  
Nucleus Pulposus Cells ◽  
Synthetic Genes ◽  
Downstream Target ◽  
Transcription Factor 4

Objective: Intervertebral disk degeneration (IDD) is a major cause of pain in the back, neck, and radiculus. Mesenchymal stem cells (MSCs)-derived extracellular vesicles (EVs) are therapeutic in musculoskeletal degenerative diseases such as IDD. This study explored the effect and functional mechanism of human bone MSCs (hBMSCs)-derived EVs in proliferation and apoptosis of degenerated nucleus pulposus cells (DNPCs) and extracellular matrix (ECM) synthesis.Methods: Extracellular vesicles were isolated from hBMSCs and identified. DNPCs were induced by TNF-α. EVs were incubated with DNPCs for 24h. Internalization of EVs by DNPCs, DNPCs proliferation, apoptosis, and expressions of ECM synthetic genes, degrading genes and miR-129-5p were assessed. Downstream target genes of miR-129-5p were predicted. Target relation between miR-129-5p and SRY-box transcription factor 4 (SOX4) was verified. DNPCs proliferation, apoptosis, and ECM synthesis were measured after treatment with EVs and miR-129-5p inhibitor or SOX4 overexpression. Expressions of SOX4 and Wnt/β-catenin pathway-related proteins were determined.Results: hBMSC-EVs promoted DNPCs proliferation, inhibited apoptosis, increased expressions of ECM synthetic genes, and reduced expressions of ECM degrading genes. hBMSC-EVs carried miR-129-5p into DNPCs. Silencing miR-129-5p in EVs partially inverted the effect of EVs on DNPCs proliferation and ECM synthesis. miR-129-5p targeted SOX4. SOX4 overexpression annulled the effect of EVs on DNPCs proliferation and ECM synthesis. Expressions of Wnt1 and β-catenin were decreased in EVs-treated DNPCs, while silencing miR-129-5p in EVs promoted expressions of Wnt1 and β-catenin.Conclusion: hBMSC-EVs promoted DNPCs proliferation and ECM synthesis by carrying miR-129-5p into DNPCs to target SOX4 and deactivating the Wnt/β-catenin axis.

scholarly journals A Comparison of the Quality of Sleep between Pre and Post-Surgery Cervical Herniated Nucleus Pulposus Patients Utilizing the Anterior Discectomy Method

2017 ◽  
Vol 5 (7) ◽  
pp. 948-954
Author(s):  
Ridha Dharmajaya ◽  
Dina Keumala Sari ◽  
Ratna Akbari Ganie
Keyword(s):  
Sleep Quality ◽  
Nucleus Pulposus ◽  
Intervertebral Disk ◽  
Quality Of Sleep ◽  
Post Surgery ◽  
Anterior Discectomy ◽  
Significant Difference ◽  
Post Operation ◽  
Herniated Nucleus Pulposus

BACKGROUND: Herniated Nucleus Pulposus (HNP) is the prolapse of the intervertebral disk through a tear in the annulus fibrosus. This causes nerve root compression with clinical pain manifestation and affects the quality of sleep.AIM: The aim of this study was find out the comparison in the quality of sleep between before (pre) and after (post) surgery cervical HNP patients.METHODS: This study was a retrospective cohort study. Ninety patients were asked to complete the Pittsburgh Sleep Quality Index (PSQI) questionnaire. All data which has been computed were analysed with the McNemar test.RESULT: The outcome reveals that from 90 patient`s cervical HNP, 81 (90%) were 40 years old age group and 66 (73.3%) of them were women. The result showed that 66 (73.3%) patients have a bad sleep quality before surgery. Surgery has increased the quality of sleep after surgery 66 (73.3%) patients had good sleep quality. There was a significant difference in the quality of sleep pre and post operation (p = 0.001).CONCLUSION: There was a significant difference in the quality of sleep between pre and post operation cervical HNP patient utilising anterior discectomy methods.

scholarly journals Electromagnetic Emissions from Quartz Subjected to Shear Stress: Spectral Signatures and Geophysical Implications

Geosciences ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 140 ◽  
Author(s):  
Giovanni Martinelli ◽  
Paolo Plescia ◽  
Emanuela Tempesta
Keyword(s):  
Shear Stress ◽  
Electromagnetic Waves ◽  
Emission Spectra ◽  
Stress Tests ◽  
Quartz Crystals ◽  
Piston Cylinder ◽  
Fracturing Process ◽  
Electromagnetic Emissions ◽  
As Stress ◽  
Energy Dissipated

Shear tests on quartz rocks and single quartz crystals have been conducted to understand the possible relationship between the intensity of detectable stress in fault areas and the energy released in the form of electromagnetic waves in the range 30 KHz-1 MHz (LF–MF). For these tests, a new type of piston-cylinder has been developed, instrumented to collect the electromagnetic signals generated by the quartz during shear stress tests and that allows energy measurements on electromagnetic emissions (EMR) to be performed. The data obtained indicate that shear-stressed quartz crystals can generate electromagnetic emissions in the LF–MF range. These emissions represent a tiny fraction of the total energy dissipated in the fracturing process. The spectrum of radio emissions consists of continuous radiation and overlapping peaks. For the first time, a characteristic migration of peak frequencies was observed, proportional to the evolution of the fracturing process. In particular, the continuous recording of the radio emission spectra shows a migration of the peaks toward higher frequencies, as stress continues over time and smaller and larger fractures form. This migration could be used to distinguish possible natural signals emitted by quartz in tectonically active environments from possible signals of other geophysical and possibly anthropogenic origin.

Evaluate the Importance of Shear Modulus in Dynamic FEM of Flexible Pavement Considering AC Cross-Anisotropy

2016 ◽  
Author(s):  
Mesbah U. Ahmed ◽  
Rafiqul A. Tarefder
Keyword(s):  
Shear Modulus ◽  
Resilient Modulus ◽  
Vertical Plane ◽  
Element Model ◽  
Tire Pressure ◽  
Stress Strain ◽  
Viscoelastic Parameters ◽  
Cross Anisotropy ◽  
As Stress ◽  
Stress Dependent

Goal of this study is to evaluate the effect of shear modulus variation on pavement responses, such as stress-strain, under dynamic load incorporating the AC cross-anisotropy. A dynamic Finite Element Model (FEM) of an instrumented asphalt pavement section on Interstate 40 (I-40) near Albuquerque, New Mexico, is developed in ABAQUS to determine stress-strain under truck tire pressure. Laboratory dynamic modulus tests were conducted on the AC cores to determine the temperature and frequency varying modulus values along both vertical and horizontal directions. The test outcomes are used to produce cross-anisotropic and viscoelastic parameters. Resilient modulus tests are conducted on granular aggregates from base and subbase layer to determine the nonlinear elastic and stress-dependent modulus values. These material parameters are integrated to the FEM through a FORTRAN subroutine via User Defined Material (UMAT) in the ABAQUS. The developed FEM is validated using the pavement deflections and stress-strain data under Falling Weight Deflectometer (FWD) test. The validated dynamic FEM is simulated under the non-uniform vertical tire contact stress. For the parametric study to investigate the effect of shear modulus variation on pavement responses, the validated FEM is simulated by varying the shear modulus in the AC layer. The results show that the variation in shear modulus along a vertical plane barely affects the tensile strain at the bottom of the AC layer and vertical compressive strains in both AC and unbound layers.

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