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In this work, the changes in hardness of Al-Zn-Mg alloy during retrogression and reaging (RRA) treatments were detected and the mechanism of the hardness change was studied by Small Angle X-ray Scattering (SAXS). It was discovered that the hardness changes during RRA treatments are as follows. (1) Hardness decreases at the beginning of retrogression, achieves a minimum value at 90 seconds, and then increases and achieves the second maximum value at 6 minutes, and finally decreases simply.(2) Hardness of the reaged sample is higher than that of the retrogressed sample. The following conclusions were drawn from the experimental results of SAXS. (1) The drop in hardness for short retrogression time is attributed to the decrease of volume fraction of the precipitates and the growth of the particles; the drop in hardness with increasing retrogression time after the second maximum of hardness achieved is attributed to coarsening of the particles. 2. The increase in hardness during reaging is due to the occurrence of new precipitates and the increase of volume fraction of the precipitates.

Purpose: To investigate the effect of propofol on lung metastasis of circulating tumor cells (CTCs) after colorectal cancer (CRC) surgery, and the mechanism involved. Methods: Specific-pathogen-free (SPF) male BALB/c mice (n = 30; mean age = 7 ± 1 weeks; mean weight = 19 ± 3 g) were used for this study. To establish mouse model of CRC, 100 μL of CRC (CT26) cells was injected into the caudal vein of each mouse. Three groups of 10 mice were used: control, 5 μL/mL propofol, and 10 μL/mL propofol groups. Changes in pulmonary superficial nodules of mice lungs were determined. Colorectal cancer cell (CT26) proliferation and apoptosis were measured using Ki-67 immunohistochemical staining and in situ terminal deoxynucleotide transferase-mediated dUTP nick end labeling (TUNEL) assays, respectively. Results: The number of pulmonary nodules and proportion of proliferating cells (Ki-67 expression level) were significantly higher in 5 μL/mL propofol-treated mice, relative to control, but markedly lower in 10 μL/mL propofol group than in 5 μL/mL propofol group (p < 0.05). Although apoptotic index increased in 5 μL/mL propofol group, cell apoptosis was comparable among the groups (p > 0.05). Conclusion: These results suggest that propofol promotes pulmonary metastasis of CTCs after CRC surgery via stimulation of CTC proliferation in the lungs. Therefore, caution should be exercised in the use of propofol in colorectal cancer surgery.

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