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Background Mammalian Ste20-like kinase 4 (MST4), also known as serine/threonine kinase 26 (STK26), promotes development of several cancers and is found to be highly expressed in the placenta. However, in choriocarcinoma that originated from the placenta, the expression of MST4 was undetermined and its mechanism was unknown. In this study, the expression of MST4 in choriocarcinoma as well as the underlying mechanism was explored. Purpose To detect the expression of MST4 in patient samples and mechanism of mediating EMT by MST4 in choriocarcinoma. Patients and Methods The metastatic lesions of choriocarcinoma (n=17) and volunteer villus (n=17) were collected to determine MST4 expression using immunohistochemistry and H&E staining. We use siRNA and lentiviral vector to knockdown MST4 and use plasmid to overexpress MST4 in choriocarcinoma. Then, we apply real-time polymerase chain reaction (RT-PCR), Western blot assay and immunofluorescence assay to detect target protein expressions. Cell invasion and migration and cell proliferation were detected by transwell assay and wound healing assay and CCK-8 and cell colony formation. Results MST4 is lowly expressed in the metastatic lesions of choriocarcinoma patients when compared with normal villus. Knockdown of MST4 activated epithelial–mesenchymal transition (EMT) process, significantly increasing the ability of invasion and migration in choriocarcinoma cell lines (JAR and JEG-3). In contrast, the EMT process was restrained in choriocarcinoma cell lines with overexpressed MST4. Meanwhile, genome-wide gene expression array, Western blot and ELISA revealed that tumor growth factor-beta 1 (TGF-β1) has significantly increased. The EMT process and metastatic prompting biofunction were reversed after using TGF-β1 inhibitor (LY364947) in the choriocarcinoma cell lines with MST4 knockdown. Conclusion Our studies demonstrated that MST4 was lowly expressed in patient samples. Additionally, JAR and JEG-3 increase cell invasion and migration ability while there is no influence on cell proliferation with MST4 knockdown. Conversely, the metastatic ability of JAR and JEG-3 was decreased with overexpressed MST4. Moreover, TGF-β1 was a key factor after MST4 knockdown. In conclusion, MST4 affects choriocarcinoma EMT by mediating TGF-β1 expression.

An optical pickup head for providing multi-dimensional multi-level (MDML) optical recording is proposed and designed according to the MDML optical recording concept which uses both intensity and polarization of light. Through dynamic testing separately with a commercial digital versatile disc rewritable (DVD-RW) disc and another disc with 0.6 mm planar substrate sputtered with magneto-optical film, the MDML optical pickup head has been proven to provide multi-level modulations of at least two physical properties of light to achieve MDML recording, e.g., multi-level reflective recording with two-level polarization recording. On the basis of the MDML optical pickup head, research on the MDML optical disc can be carried out. In addition to the MDML recording function, the MDML optical pickup head is compatible with DVD formats.

An integrated analysis tool of optical system and media is developed. The optical system and media design has been conducted for advanced optical storage. This software possesses practical capabilities of optical system and media design.

The thermal effect on slider in heat assisted magnetic recording is studied with experiments and simulation. The temperature distribution on the slider induced by locally heated media at higher density case is given.

In comparison with the conventional grain-oriented electrical steels(the so-called CGO steels),the high permeability electrical steels(the so-called Hi-B steels) including those of nitrided steels possess higher magnetic properties,but their processing window is narrow.In particular,a near brass-oriented texture which rotated around the normal direction of sheets from Goss orientation is often observed in improperly processed sheets of Hi-B steels,i.e,this type of sheet possesses a correct morphological structure of well abnormally grown grains,but a poor crystallographic texture with low magnetic properties.The underlying mechanism is less dealt with in literature in comparison with the formation of Goss texture.Thus,the objective of this work is to analyze the formation mechanism of this texture component.For this purpose,XRD and EBSD technique were applied to reveal both macro- and micro-textures from the shear texture of hot rolled plate surface to primarily and secondarily annealed sheets paying particular attention to the origin and relationship of Brass-oriented grains with their surrounding grains.It is demonstrated that Brass-oriented grains are formed by the rotation of Goss-oriented grains around the normal direction in the sheared surface layer of hot rolled plate when the shearing around transverse direction is restrained.Compared with the close relation between Goss and {111}(112) oriented grains, similar behaviors during cold rolling and annealing occur between brass- and {lll}(110)-oriented grains,namely,the latter are also inclined to be adjacently related and mutual transformation could occur between those deformation grains and recrystallization grains.In particular,a higher rolling reduction reduces Goss grain number much significantly,whereas it favors the retention of brass- and {111}〈110〉-oriented grains leading to preferred growth of brass-oriented grains.In the condition of easy growth of Brass grains with their {110} being parallel to rolling plane like Goss grains in the thinner sheets,the much fewer Goss grains could not swallow the brass-oriented grains.Thus,this technical issue of producing grain oriented electrical steels with high magnetic properties can be understood in terms of fundamentals of texture evolution during deformation and recrystallization of bcc metals.