This paper aimed to explore the mechanical properties of a cement-based material with carbon nanotube (CNT) under drying and freeze-thaw environments. Mercury Intrusion Porosimetry and Scanning Electron Microscopy were used to analyze the pore structure and microstructure of CNT/cement composite, respectively. The experimental results showed that multi-walled CNT (MWCNT) could improve to different degrees the mechanical properties (compressive and flexural strengths) and physical performances (shrinkage and water loss) of cement-based materials under drying and freeze-thaw conditions. This paper also demonstrated that MWCNT could interconnect hydration products to enhance the performance of anti-microcracks for cement-based materials, as well as the density of materials due to CNT’s filling action.

The purpose of this study was to determine whether vitamin E or vitamin C supplementation alters the DNA damage of whole blood white blood cells (WBC) in patients with chronic obstructive pulmonary disease (COPD). Thirty-five patients with stable COPD were recruited in this randomized and placebo-controlled study. Patients were randomly assigned to placebo (n = 8), 400 mg/day vitamin E (E400, n = 9), 200 mg/day vitamin E (E200, n = 9), or 250 mg/day vitamin C (C250, n = 9) for 12 weeks. The results showed that vitamin E or C supplementation did not significantly change the mean level of endogenous DNA breakages. Whereas, after 12 weeks of vitamin supplementation, the H2O2-induced DNA breakages were significantly suppressed by 45%, 59%, and 52%, respectively, in E400, E250 and C250 groups (p < 0.05). In addition, neither the level of thiobarbituric acid-reactive substances (TBARS) nor spirometric parameters were significantly changed after 12 weeks of supplementation. In conclusion, vitamin E or C supplementation for 12 weeks may improve the resistance of DNA in whole blood WBC against oxidative challenge, although more research is needed to demonstrate the beneficial effect on slowing the decline of lung function in patients with COPD.

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Carbon nanotubes (CNTs) have shown promise for improving the mechanical performance of cement composites through crack-bridging and frictional pull-out. The interactive behaviors between CNTs and cement matrix act are crucial in optimizing the reinforcement of CNTs in cement composites. This study investigates the effects of nano-silica (NS) sol-gel on the interactive behaviors of CNTs and the cement matrix through a series of experiments and analyses. UV-visible spectrometer results show that CNTs are well-dispersed in suspension and the addition of NS has a negligible effect on the stability of CNT dispersion. Calorimetry tests and dynamic mechanical analysis demonstrate the nucleation and frictional performance of CNTs in cement matrix, respectively. The paper shows that the physical adsorption of NS on the CNT surface could result in the acceleration of cement hydration. Morphology observation confirms that a denser interface between CNTs and cement hydrates is formed. Finally, the improved interaction between CNTs and cement hydrates leads to a substantial increase in friction between CNTs and the cement matrix under periodic loading. NS may act as an ideal admixture for improving both the interactive behaviors between CNTs and cement matrix and the damping properties of cement composite.