Autophagy (macroautophagy) is a degradative process that involves the sequestration of cytosolic material including organelles into double membrane vesicles termed autophagosomes for delivery to the lysosome. Autophagy is essential for preimplantation development of mouse embryos and cavitation of embryoid bodies. The precise roles of autophagy during early human embryonic development, remain however largely uncharacterized. Since human embryonic stem cells constitute a unique model system to study early human embryogenesis we investigated the occurrence of autophagy in human embryonic stem cells. We have, using lentiviral transduction, established multiple human embryonic stem cell lines that stably express GFP-LC3, a fluorescent marker for the autophagosome. Each cell line displays both a normal karyotype and pluripotency as indicated by the presence of cell types representative of the three germlayers in derived teratomas. GFP expression and labelling of autophagosomes is retained after differentiation. Baseline levels of autophagy detected in cultured undifferentiated hESC were increased or decreased in the presence of rapamycin and wortmannin, respectively. Interestingly, autophagy was upregulated in hESCs induced to undergo differentiation by treatment with type I TGF-beta receptor inhibitor SB431542 or removal of MEF secreted maintenance factors. In conclusion we have established hESCs capable of reporting macroautophagy and identify a novel link between autophagy and early differentiation events in hESC.

In order to eliminate cracks in the chromium coating, a novel method named flexible extrusion assisted chromium electroplating was proposed. The bright and crack-free chromium coatings were electrodeposited by using the perturbation and extrusion of hard and insulating particles. The prepared deposits were characterized by scanning electron microscope (SEM) and three-dimensional topography. The testing results showed that the surface was very smooth and there was no micro cracks in the coating. Micro hardness of the electrodeposited layer was also tested. It was confirmed that the chromium coating electrodeposited with rotating cathode in hard particles had high micro hardness as to 850HV and the micro hardness could be controlled by the process parameters. The rule of the micro hardness was concluded by analyzing current density and rotating speed. In addition the results of salt spray test and electrochemical polarization curve showed that the coating deposited by new method had higher corrosion resistance than that by traditional method.

In order to obtain the sheet metal anisotropy under wide strain range, plane strain compression method with laminated samples is investigated. In the experiments, two laminated samples are introduced, sample 1 is deformed at rolling and thickness direction, and sample 2 is deformed at rolling and transverse direction. In the paper, the ratio of deformation forces obtained from sample 2 (p2) to sample1( p1) is used to assess the anisotropy of sheet metal, and verified by analytical method. The results show that the ratio of p2top1is the function of anisotropic index r, and the anisotropic assessment by this method has a good agreement with that obtained by universal uniaxial tensile test at uniform deformation.

Aluminum ball joint is an advanced structure using to connect steering parts with the merits of simple and lighting. Usually extrusion strength and torque are the most important parameters to evaluate the ball joint properties. Generally, the ball sealed in the Aluminum housing by forming method which has an impact on the extrusion strength and torques. So how to control the forming and achieve the best properties is very important. In the paper, the relations between housing dimension and strength, torque are studied; the influence of forming on torque is researched. The rules in them are achieved.

Bearing sleeve, as one of important parts of bearing structure, determine the bearing performance directly. In this paper, based on the ball joint structure, the tribological properties between Polyoxymethylene (POM) and 40Cr are studied with Ring-Block method. The effects of friction velocity and applied load on friction coefficient are tested and analysed, the analytical model in friction force, friction velocity and applied load are created, which will provide useful technical data to the application.