Deflection Intelligent Prediction for High-Strength Steel Saddle Plate Forming Applicable to Reducing Ship Weight.

The application of high-strength steel plates can reduce ship weight, and the saddle plate is one of the most common types of double-curved hull plates. To fill the research gap regarding high-strength steel saddle plates, two prediction models are established here to predict deformation in saddle plate forming. Deflection is a key parameter reflecting the overall deformation of a curved plate. Therefore, first of all, the influencing factors of the line heating of high-strength steel saddle plates were analyzed. The influence of plate geometric parameters and forming parameters on deflection was researched. Second, a multiple linear regression model between deflection and the geometric parameters and forming parameters of high-strength steel saddle plates was established. Finally, to solve the problem of a large error in the multivariate regression model for extrapolation, an intelligent prediction program for deflection based on a support vector machine (SVM) was developed using the Python language. The results show that the error of the multiple regression model was less than 5% for data interpolation. The error of the intelligent prediction model for deflection was less than 5% for data extrapolation. This research can provide data support for the automatic forming of marine saddle plates.

Numerical Calculation of High-Strength-Steel Saddle Plate Forming Suitable for Lightweight Construction of Ships.

With the demand for construction of lightweight ships and polar ships, high-strength steel is increasingly applied in shipbuilding. There are a large number of complex curved plates to be processed in ship construction. The main method for forming a complex curved plate is line heating. A saddle plate is an important type of double-curved plate, which affects the resistance performance of the ship. The existing research on high-strength-steel saddle plates is lacking. To solve the problem of forming for high-strength-steel saddle plates, the numerical calculation of line heating for a EH36 steel saddle plate was studied. By combining it with a line heating experiment of low-carbon-steel saddle plates, the feasibility of numerical calculation based on the thermal elastic-plastic theory for high-strength-steel saddle plates was verified. Under the premise that the processing conditions such as the material parameters, heat transfer parameters, and the constraint mode of the plate were correctly designed, the effects of the influencing factors on deformation of the saddle plate could be studied by the numerical calculation method. The numerical calculation model of line heating for high-strength-steel saddle plates was established, and the effects of geometric parameters and forming parameters on shrinkage and deflection were studied. This research can provide ideas for the lightweight construction of ships and provide data support for automatic processing of curved plates. It can also provide inspiration for curved plate forming in fields such as aerospace manufacturing, the automotive industry, and architecture.

MiR-501-3p promotes osteosarcoma cell proliferation, migration and invasion by targeting BCL7A.

Increasing numbers of evidences have demonstrated that microRNAs (miRNAs) play an important role in osteosarcoma (OS) cell functions. MiR-501-3p has been reported to play an important role in several types of tumors, including prostate cancer and hepatocellular carcinoma. However, the biological function and potential mechanism of miR-501-3p in OS have not been well investigated until now. Here, we analyzed the expression of miR-501-3p in OS tissues and cell lines and its clinical significance in OS patients. Quantitative reverse transcription PCR showed miR-501-3p was significantly up-regulated in OS tissues and cell lines. Up-regulated miR-501-3p expression was associated with TNM stage, distal metastasis and worse prognosis in OS patients. MiR-501-3p knockdown and overexpression were achieved by miR-501-3p inhibitor and mimics transfection, respectively. CCK-8, colony formation and transwell assays showed that miR-501-3p knockdown in U2OS and Saos-2 cells suppressed, while miR-501-3p overexpression in Saos-2 cells promoted cell proliferation, migration and invasion. Moreover, luciferase reporter assay supporting BCL7A was a target of miR-501-3p and its expression was increased by miR-501-3p inhibitor, but inhibited by miR-501-3p mimics. By performing rescue experiments, we further demonstrated that BCL7A was a downstream functional regulator involved in miR-501-3p promoting OS cell functions. In summary, our findings suggest that miR-501-3p targets BCL7A may provide novel therapeutic targets for the treatment of OS.

[Effect of rabbit peripheral sensory and motor nerve homogenates on the proliferation and calcification of rabbit osteoblasts in vitro].

OBJECTIVE: To investigate the effect of rabbit saphenous and sciatic nerve homogenates on the proliferation and calcification of rabbit osteoblasts in vitro. METHOD: The saphenous nerves (sensory nerves) and the muscular branches of the sciatic nerve (motor nerve) were collected from 48 New Zealand white rabbits to prepare the nerve tissue homogenates. Bone marrow mesenchymal stem cells (MSCs) were isolated from the rabbits and cultured in vitro, and after 14 days of routine osteogenic induction, the resultant osteoblasts were identified by immunohistochemistry, alkaline phosphatase (ALP) and Alizarin red S staining. The osteoblasts were then incubated in the induction medium containing the saphenous (sensory nerve group) or sciatic homogenates (motor nerve group), with the cells in the dexamethasone-containing, dexamethasone-free osteogenic induction medium and control medium as the control. The proliferation, total protein and ALP activity of the osteoblasts were measured every other day until the 8th day, and Alizarin red S staining was used for quantitative analysis of calcification of the cells after two weeks. RESULTS: The application of the saphenous nerve homogenates significantly promoted cell proliferation, total protein and ALP activity (P<0.01, P<0.05 and P<0.05), while exposure of the osteoblasts to dexamethasone inhibited the cell proliferation (P<0.001). Compared to dexamethasone-free group, the saphenous homogenates enhanced the mineralization of the osteoblasts (P<0.001). CONCLUSION: Saphenous nerve homogenates significantly promotes the proliferation, differentiation, ALP activity and mineralization of rabbit osteoblasts, but sciatic nerve homogenates do not show osteogenic effects on the cells.