Recurrence and metastasis are commonly associated with poor prognosis of hepatocellular carcinoma (HCC). Therefore, a better understanding of molecular mechanisms involved in HCC metastasis may lead to more effective treatment for HCC patients. Rac plays important roles in cytoskeletal reorganization leading to cell motility in renal and breast carcinomas. However, the role of Rac is controversial in tumors and has not been studied in HCC. The aim of this study was to investigate the importance of the Rac signaling pathway in HCC cell motility and the anti-metastatic potential of FTY720. Recently a pair of HCC cell lines from a primary tumor (H2P) and its matched metastasis (H2M) was established. These two cell lines provide a useful tool for the study of HCC metastasis. The results show that the Rac signaling pathway is activated in the metastatic HCC cell line (H2M) compared with the primary HCC cell line (H2P). FTY720 specifically suppressed H2M cell motility by down-regulation of the Rac-GTP level through inhibition of phosphoinositide 3-kinase activity. To conclude, this study is the first to demonstrate an essential role of Rac signaling pathway activation in HCC metastasis and suppression of cell motility by FTY720 through blocking of the Rac pathway.

With the high speed railway utilization, the probability of defects or fatigue cracks in railway axles is increased. An automatic ultrasonic inspection system for railway axles is presented. This system uses combined probes and inspects the defects with spiral trajectory along the axis of the axle. Through the matrix representation of C-scan image element, a defect edge extraction method is adopted, with which the defect parameters of crack are obtained automatically. Based on these defect parameters, the stress intensity factor is assessed by svm regression and the method to predict remaining life is proposed.

Due to the virtue in energy consumption, response time and work reliability, the magneto-rheological (MR) damper is a new promising devices for vibration control, in which the controller input expected control force and piston velocity to justify MR damper input voltage, so that desired damper force is achieved. It follows that the functional relationship between input voltage, expected control force and piston velocity is important for MR damper application. In this paper, a novel simplified and high-precision inverse dynamics model is derived based on MR damper Bouc-Wen phenomenological model, by which the input voltage of MR damper is calculated by means of expected control force and piston velocity. To verify the validity of this proposed inverse dynamics model, two numerical simulations of MR damper force following tests are introduced in the latter of this paper.

Initiation of blade cracks in Francis turbine runners endangers the safety operation of power stations, so it is crucial to detect the cracks before emergencies happen. This article is a preliminary study of applying acoustic emission (AE) technique to detecting the large-scale turbine runners. A series of experiments had been carried out on an HLA286a-LJ-800 Francis turbine runner. The attenuation characteristics due to propagation distance were studied. From the tests, it is concluded that AE signals are detectable after propagating at a distance of 6 m. The propagation distance is the major factor of attenuation. As a result, although attenuation is incurred, it is feasible to apply AE technique to monitoring crack signals in runners. However, it depends on the understanding of background noise and extraction of right signals.

GCr15 bearing steel exhibits comparatively serious center macro-segregation in the continuous casting of bloom with the increase of casting speed. In the present work, the influence of complex electromagnetic stirring (M + F-EMS) and mechanical soft reduction (MSR) on the center macro-segregation in the continuous casting of 220 × 260 mm blooms of GCr15 bearing steel have been comparatively investigated to increase casting speed in order to ensure a good internal quality. Based on numerical simulation and experiments, M + F-EMS and MSR have been comprehensively evaluated and compared by combination of industrial trials. The results show that center carbon segregation first decreases and then increases with the increase of casting speed in both processes without optimization. For M + F-EMS process, when casting speed increases from 0.75 to 0.85 m · min−1, the average degree of center carbon segregation decreases from 1.2 ∼ 1.26 to 1.18 ∼ 1.25 by asymmetrical optimization; with regard to combination of M + F-EMS and MSR process, when casting speed increases from 0.75 to 0.9 m · min−1, the average degree of center carbon segregation decreases from 1.2 ∼ 1.26 to 1.08 ∼ 1.1 and the solute element distribution becomes homogeneous by optimization. In comparison, significant reduction of the center macro-segregation with the increase of casting speed can be achieved for combination of M + F-EMS and MSR process, however, it is infeasible for M + F-EMS process in the present technology situation.