Effect of Vehicle–Bridge Coupled Vibration on the Performance of Magnesium Phosphate Cement Repair Materials

This study evaluates the effect of vehicle–bridge coupled vibration on the mechanical properties of fiber-reinforced magnesium phosphate cement (FR-MPC) composites and the bonding properties of repaired systems. By means of compressive and flexural bond strengths, fiber pullout, mercury intrusion porosimeter (MIP) and backscattered electron imaging (BSE) analysis, an enhanced insight was gained into the evolution of FR-MPC performance before and after vibration. Experimental results showed that the compressive strength and flexural strength of FR-MPC was increased when it was subjected to vibration. However, the effects of vibration on the flexural strength of plain magnesium phosphate cement (MPC) mortars was insignificant. The increased flexural strength of FR-MPC after vibration could be due to the high average bond strength and pull-out energy between the micro-steel fiber and the MPC matrix. Moreover, BSE analysis revealed that the interface structure between FR-MPC and an ordinary Portland cement (OPC) substrate was more compacted after vibration, which could possibly be responsible for the better bonding properties of FR-MPC. These findings are beneficial for construction project applications of FR-MPC in bridge repairing and widening.

THE RELATIONSHIP BETWEEN INFLAMMATION MARKERS AND MAGNESIUM/PHOSPHATE RATIO WITH ENDOTEL FUNCTION IN PERIPHERAL ARTERY DISEASE

Objective: In our study, it was aimed to evaluate the relationship between neutrophil/lymphocyte, monocyte/high-density lipoprotein and magnesium/phosphate ratios with endothelial functions in patients with peripheral artery disease. Methods: Sixty patients followed up with peripheral arterial disease were included in this study. Endothelial functions of the patients were evaluated by flow-mediated vasodilation test. Pearson correlation analysis was used to evaluate the relationship between magnesium/phosphate, neutrophil/lymphocyte, monocyte/high-density lipoprotein ratios with percent change in flow-mediated vasodilation. Results: 48.3% of the participants are male and 51.7% are female. The mean age of the patients were 66.85±11.08 years. The mean radial artery basal diameter was 0.24±0.02 cm in the flow-mediated vasodilatation test and after the test the mean radial artery diameter was 0.27±0.02 cm(p<0.001). In the flow-mediated dilatation test predicting endothelial functions, the percentage change in arterial diameter was positively correlated with the Magnesium/phosphate ratio (r=-0.326, p=0.011), and negatively correlated with the Neutrophil/lymphocyte ratio and monocyte/high-density lipoprotein ratio (respectively r= -0.411, p=0.001; r=-0.530, p=0.001). Conclusion: Magnesium/phosphate ratio, neutrophil/lymphocyte ratio and monocyte/high-density lipoprotein ratio can be used to predict endothelial dysfunction in patients with peripheral artery disease.