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This study aimed to determine the effect of brazilin on the invasion and metastasis of breast cancer. The breast cancer MDA-MB-231 and 4T1 cells were treated with brazilin to investigate proliferation and invasion using cell proliferation assay, wound healing assay, transwell assay. BALB/C mice were randomized into normal, model, positive control, and Sappan L. extract groups (n=6/group). The mice were injected with 4T1 cells via caudal veins to establish a lung metastasis model and via subcutaneous injection to establish a xenograft model. Metastatic nodules on the lung surface, survival rates and visceral indices were evaluated. Subcutaneous tumor volumes and weights were measured. Brazilin inhibited the proliferation of breast cancer cells and significantly inhibited the wound healing, migration, and invasion of MDA-MB-231 and 4T1 cells. Compared with the normal group, the average survival days and spleen index in the model group were significantly decreased, but the lung index and number of pulmonary metastatic nodules were significantly increased. Compared with the model group, the average survival and spleen index of dose groups were significantly increased, and the lung index, the number of pulmonary metastatic nodules, and tumor volume and weight were significantly decreased. Brazilin significantly inhibits the proliferation and metastasis of breast cancer. This study might suggest a new therapeutic agent for breast cancer.

Cracking of concrete induced by rebar corrosion is a main cause for deterioration of reinforced concrete structures especially for those exposed to chloride environment. In all of the parameters influencing the service life of concrete structures, water-to-cement ratio is a very important one for it determines the resistance of concrete against chloride aggression and corrosion-induced damage. In this paper, the parameters in corrosion process influenced by water-to-cement ratio of concrete (w/c) are screened all-round which include concrete tensile strength f t , elastic modulus E c , porous zone thickness δ 0 , corrosion current density i corr , critical chloride content C cr , and chloride diffusion coefficient D cl . The influences of w/c on the chloride penetration stage and the corrosion damage stage are studied. The first stage is expressed by Fick's second law, and the second stage is calculated using a commonly used analytical model, i.e. the thickwalled cylinder model. It is found that with the increase of w/c, the change of some parameters (f t ", C cr ", D cl #, i corr #) will induce increase of the service life, while the change of the others (E c ", δ 0 #) will induce decrease of the service life.The diffusion stage and damage stage both shorten with the increase of w/c, and thus the total service life decreases with the increase of w/c. These results show that the increase of w/c presents a negative effect on the service life of concrete structures in total. In addition, with the increase of w/c, the service life for various concrete cover thicknesses and rebar diameters decrease in a similar tendency. For probability analyses, it is found that the probability density curves under different w/c are almost symmetric but show a little left-skewed, and the total service life for various w/c fluctuates about 0.6 to 1.0 year.chloride diffusion, cover cracking, rebar corrosion, service life, water-to-cement ratio | INTRODUCTIONRebar corrosion is a serious problem affecting the durability and safety of reinforced concrete structures which reduces cross-section of rebar, bond strength between the corroded rebar and concrete and induces cracking of Discussion on this paper must be submitted within two months of the print publication. The discussion will then be published in print, along with the authors' closure, if any, approximately nine months after the print publication.