Purpose: The intervertebral disc (IVD) is a complex, flexible joint between adjacent vertebral bodies that provides load transmission while permitting movements of the spinal column. Finite element models can be used to help clarify why and how IVDs fail or degenerate. To do so, it is of importance to validate those models against controllable experiments. Due to missing experimental data, shear properties are not used thus far in validating finite element models. This study aimed to investigate the structural shear properties of human lumbar IVDs in posteroanterior (PA) and laterolateral (LL) loading directions.
Methods: Fourteen lumbar IVDs (median age: 49 years) underwent direct shear in PA and LL loading directions. A custom-build shear device was used in combination with a materials testing machine to load the specimens until failure. Shear stiffness, ultimate shear force and displacement, and work to failure were determined.
Results: Each specimen was tested until complete or partial disruption. Median stiffness in PA direction was 490 N/mm and in LL direction 568 N/mm. Median ultimate shear force in the PA direction was 2,877 N and in the LL direction 3,199 N. Work to failure was 12 Nm in the PA and 9 Nm in the LL direction.
Conclusions: This study was an experiment to subject IVDs to direct shear. The results could help us to understand the structure and function of IVDs with regard to mechanical spinal stability, and they can be used to validate finite element models of the IVD.
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http://dx.doi.org/10.5301/jabfm.5000176 | DOI Listing |
Sci Rep
January 2025
College of Hydraulic and Civil Engineering, Xinjiang Agricultural University, 311 East Nongda Rd, Urumqi, 830052, China.
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January 2025
Department of Hydrodynamic Systems, Faculty of Mechanical Engineering, Budapest University of Technology and Economics, Műegyetem rkp. 1-3, Budapest, 1111, Hungary.
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View Article and Find Full Text PDFPhys Chem Chem Phys
January 2025
State Key Lab of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China.
Mechanoresponsive colloidal photonic crystals embedded in elastic solid matrices exhibit tunable optical properties under mechanical force, showing great potential for various applications. However, the response of colloidal crystals embedded in a liquid matrix remains largely unexplored. In this study, we investigate the structural and optical transitions of colloidal crystals composed of particles suspended in a liquid oligomer under pressing and shear forces.
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January 2025
College of Animal Sciences, Anhui Science and Technology University, Fengyang, 233100, China.
This study was aim to investigate the effects of lipoic acid (ALA) on performance, meat quality, serum biochemistry and antioxidant function of broilers under heat stress (HS). Two hundred1-day-old Cobb broilers were randomly divided into four treatment groups and each treatment consisted of 4 replicates of 10 broilers each. The treatment group adopts a 2 × 2 two-factor setting, which is divided into two diets (basic diet or 250 mg/kg ALA diet) and two temperatures (24 ± 1℃ or 33 ± 1℃).
View Article and Find Full Text PDFActive fluids are driven out of thermodynamic equilibrium by internally generated forces, causing complex patterns of motion. Even when both the forces and motion are measurable, it is not yet possible to relate the two, because the sources of energy injection and dissipation are often unclear. Here, we study how energy is transferred by developing a method to measure viscosity from the shear stresses and strain rates within an epithelial cell monolayer.
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