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BACKGROUND: According to reports in the literature, osteoporotic vertebral compression fracture (OVCF) is associated with paraspinal muscle degeneration; however, the association between the severity of OVCF and paraspinal muscle degeneration is not clear. OBJECTIVE: The purpose of this study was to investigate the association between paraspinal muscle degeneration and OVCF severity in postmenopausal women. METHODS: Three hundred and seventy-six MRI images from 47 patients were collected and analyzed. Sagittal and axial coronal T2-weighted images were used to measure the fractured vertebra sagittal cross-sectional area (FSCSA), the adjacent normal vertebral body sagittal cross-sectional area (NSCSA), paraspinal muscle cross-sectional area (CSA), and the fat cross-sectional area (FCSA). The ratio of fractured vertebra compressed sagittal cross-sectional area (RCSA) and fatty infiltration ratio (FIR) was subsequently calculated. The formulas for RCSA and FIR calculations are as follows: RCSA = (NSCSA-FSCSA)/NSCSA; FIR = FCSA/CSA. RCSA and FIR represent the severity of OVCF and paraspinal muscle degeneration, respectively. RESULTS: The correlation between paraspinal muscle degeneration and OVCF severity was analyzed using the Pearson correlation, and multiple regression analysis was performed to explore related risk factors. OVCF severity was closely associated with paraspinal muscle degeneration (L3/4 FIR r= 0.704, P< 0.05; L4/5 FIR r= 0.578, P< 0.05; L5/S1 FIR r= 0.581, P< 0.05). Multiple regression analysis demonstrated that the risk factor for OVCF severity was L3/4 FIR (β= 0.421, P= 0.033). CONCLUSION: OVCF severity was associated with the FIR of paraspinal muscles, and L3/4 FIR was a predictive factor for OVCF severity in postmenopausal women.

With the excellent high temperature performance and irradiation stability, the SiCf/SiC composites are considered as a kind of promising new fuel cladding material. The joint between the end plug and cladding is one of the key problems affecting its application. In this research, the connection between SiCf/SiC composites was realized by diffusion bonding, and the microstructure and reaction products in the joint area were analyzed by SEM and XRD. The results showed that continuous dense interface layer could be formed at the junction by the chemical reaction between Ti and silicon carbide, and the interface reaction products were TiC and Ti5Si3. The interface layer formed a sawtooth structure at the junction with SiCf/SiC composites. The chemical reactivity of the SiC fiber was weaker than that of the substrate, and there were gaps in the interface layer, which limited the diffusion of the interface reaction to the composite materials. There were long and thin interfacial phases in the pores of the materials, which formed strong mechanical occlusion with the SiCf/SiC composites and improved the degree of interfacial layer bonding.