Research on an Identification Method for Wheelset Coaxial Wheel Diameter Difference Based on Trackside Wheelset Lateral Movement Detection.

The wheelset coaxial wheel diameter difference is one of the most common wheel faults of railway vehicles. The existence of the wheelset coaxial wheel diameter difference may lead to the off-load operation of vehicles, resulting in abnormal wheel tread wear, leading to the deterioration of the wheel-rail contact relationship, resulting in the deterioration of the vehicle's operating stability and comfort, and even leading to an increase in the derailment coefficient, affecting the running safety. In order to monitor the freight car wheelset coaxial wheel diameter difference online, a vehicle-track coupling dynamics model based on a trackside detection method was established, and the response of rail lateral displacement under the condition of the wheelset coaxial wheel diameter difference was analyzed. The results show that the existence of the wheelset coaxial wheel diameter difference can lead to a deviation in the vehicle's run, with an increase in the wheelset coaxial wheel diameter difference and an increase in the lateral offset of wheelset increases. The impact of vehicle unbalance loading on the lateral movement of the wheelset is much smaller than that of the wheelset coaxial wheel diameter difference. The existence of the wheelset coaxial wheel diameter difference can be better reflected by detecting the wheelset's lateral displacement. On straight line, the variation of lateral displacement has no infection of vehicle speed, but shows a quadratic growth trend with the wheelset coaxial wheel diameter difference. Based on this, the mapping relationship between the wheelset coaxial wheel diameter difference and wheelset lateral displacement can be obtained. Through a mapping relationship, the size of the wheelset coaxial wheel diameter difference can be reversed precisely through the detection of a trackside lateral movement monitoring system. The reliability of the identification method was verified with a specific test on the trackside monitoring system.

Enhanced in vitro invasiveness of ovarian cancer cells through up-regulation of VEGF and induction of MMP-2.

Vascular endothelial growth factor (VEGF) has been identified to be important in tumor angiogenesis, which is essential for the growth, invasion, and metastasis of solid tumors. The aim of this study was to determine the effect of VEGF overexpression on the invasion of human epithelial ovarian cancer cells in vitro and the possible mechanism involved. The VEGF165 cDNA was transfected into ovarian tumor cell lines CAOV3 and COC1 to promote the expression of VEGF. The VEGF expression and matrix metalloproteinase (MMP)-2 activity were examined by RT-PCR, Western blot analysis and gelatin zymography. A modified Boyden chamber assay was used to test tumor cell invasion in vitro. All cells overexpressing VEGF displayed an enhanced in vitro invasiveness through Matrigel-coated filters with Boyden chamber invasion assay. MMP-2 mRNA and protein were significantly increased during VEGF165 cDNA transfection; MMP-2 activity was also increased. The invasion property of ovarian cancer cells was abrogated with VEGF neutralizing antibody. Our data indicated that the expression of VEGF gave impetus to the in vitro invasion of ovarian cancer cells by stimulating the production and functional activities of MMP-2, which may be a key component of VEGF in promoting ovarian cancer cell invasion. VEGF may constitute a novel therapeutic target for antiangiogenic cancer therapy.