As one of the important influencing factors of tailings dam stability, seepage field distribution within the dam is often affected by the tailings mineral characteristics. While the alkalinity or acidity of reservoir water and long term immersion will partially change the physical and mechanical properties of tailings. This study carried out permeability tests of tailings under the action of chemical solution. On this basis, a three dimensional (3D) model was constructed to analyze the velocity field and effective saturation within the tailings dam. Moreover, the dam section along the valley bottom was selected as the basic section in calculation, so as to analyze the changes in infiltration point and buried depth of the phreatic line under different permeability coefficient ratios. The results suggest that, under the action of acid-alkaline solution, the permeability coefficients of tailings reduced, and the stronger solution acidity-alkalinity resulted in the longer action time and more obvious change; under the action of chemical solution, the fluid flow velocity in the dam gradually decreased, and the drat beach length in the reservoir gradually shortened. Besides, when the upper layer permeability coefficients of tailings was lower than that of the lower layer, the dam phreatic line had a shallow buried depth and a high infiltration point.

AimTo evaluate the expression and clinical significance of hepatoma-derived growth factor (HDGF) in epithelial ovarian cancer (EOC).BackgroundRecent studies have demonstrated that HDGF overexpression correlates to the progression and poor prognosis in several kinds of cancers. However, the clinical significance and prognostic value of HDGF in EOC have not been investigated.MethodsExpression of HDGF was visualized by immunohistology and then the cohort was divided into higher- and lower-expression groups. The correlation between HDGF and clinicopathologic factors was analyzed by χ2 test. The prognostic value of HDGF was assessed by univariate analysis with Kaplan–Meier method, and by multivariate analysis with Cox-regression model. With experiments in vitro, HDGF expression in ovarian cancer cell lines was detected by immunoblotting.ResultsHigher HDGF expression rate was 52.76% in EOC. HDGF expression was significantly associated with lymphatic metastasis (P=0.006). Higher HDGF expression was closely correlated to poorer 5-year overall survival rate with univariate analysis (P=0.003), and was identified as an independent prognostic factor with multivariate analysis (P=0.007). With experiments in vitro, HDGF was proved to exist in all ovarian cancer cell lines with different expression levels.ConclusionHDGF expression correlates to unfavorable prognosis and can be considered as an independent prognostic factor, indicating that HDGF may be a promising potential molecular drug target.

Analysis of the movement trajectory and risk assessment of the high-slope dangerous rock mass collapse are of great significance for preventing and controlling the geological disasters of collapse. This study firstly takes the dangerous rock mass of the high slope in Pu’erdu Town, Yanjin County, Zhaotong City, Yunnan Province, as the research object, calculates and analyzes the trajectory of collapse movement of several groups of dangerous rock mass with great threat, and RocFall are used to carry out numerical simulation analysis and verification. Secondly, the risk and vulnerability of the dangerous rock mass in the study area are analyzed, and the risk evaluation is carried out through the risk evaluation matrix to clearly define the risk level. Results show that if the dangerous rock mass collapses, the horizontal movement distance was approximately 53–88 m, and the maximum bounce height of the platform was approximately 3–18 m, which will seriously threaten the life and property safety of residents. There is little difference between the simulation of the collapse of dangerous rock mass by RocFall software and the calculation result of the formula. Although RocFall software is more intuitive and can be directly compared with charts, software cannot completely simulate the actual situation, and it is only suggested as a reference from design rather than a basis of design. The result of risk evaluation shows that there are 2 high-risk dangerous rocks, 3 medium-risk dangerous rocks, and 1 low-risk dangerous rock in this area. It is suggested that a reasonable and scientific engineering treatment scheme should be put forward as soon as possible in combination with the collapse trajectory of the collapsing movement.

A certain 4D plateau international airport is to be built in a karst area with widespread heavy red clay strata. It is one of the major research subjects facing the engineering construction to use the red clay strata as the bearing stratum of foundation of the high-fill section. By using the 3D finite element method, the stress, strain, deformation and stability of the high-fill slope and foundation were simulated. The obtained results can be used as the basic and practical reference data for engineering construction.