Localization and Mobility Gap in Topological Anderson Insulator

It has been proposed that disorder may lead to a new type of topological insulator, called topological Anderson insulator (TAI). Here we examine the physical origin of this phenomenon. We calculate the topological invariants and density of states of disordered model in a super-cell of 2-dimensional HgTe/CdTe quantum well. The topologically non-trivial phase is triggered by a band touching as the disorder strength increases. The TAI is protected by a mobility gap, in contrast to the band gap in conventional quantum spin Hall systems. The mobility gap in the TAI consists of a cluster of non-trivial subgaps separated by almost flat and localized bands.Comment: 8 pages, 7 figure

Identification of a certain mechanism’s recoiling mass by limited memory least square method

This paper is concerned with the identification problem of a certain mechanism’s dynamic parameters in its operation. This mechanism can be simplified as three rigid body structure joined by a prismatic pair, a revolute pair and a fixed constraint. The unrestraint dynamic equations of the mechanism can be obtained by using multi-rigid-body theory. In order to acquire unknown dynamic parameters, such as displacement, velocity and acceleration, a field experiment was designed. Then by choosing limited memory least square method and using the experiment results, one mass of rigid body could be identified. Finally, the calculative mass was compared to the “real” mass which was consulted in the specification book of this mechanism. The whole process shows that the rigid dynamic model of this mechanism and the method of identification are both effective

β-Elemene enhances cisplatin-induced apoptosis of nasopharyngeal carcinoma cells involving an endoplasmic reticulum stress pathway

Purpose: To investigate whether β-elemene can enhance the anticancer activity of cisplatin in nasopharyngeal carcer (NPC) 5-8F cells and the possible molecular mechanism involved. Methods: The cytotoxicity of β-elemene and its combination with cisplatin in 5-8F cells was evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Cell cycle arrest was assessed by flow cytometry. Immunoblotting was performed to determine the expression levels of proteins related to the cell cycle (cyclin D1, p21, p27) and to cell apoptosis (Bax, cleaved caspase 9, Bcl-2, and cleaved caspase 3), as well as the endoplasmic reticulum (ER) stress pathway associated proteins. Results: In 5-8F cells, β-elemene (40 μg/mL) and cisplatin (10 mM) exhibited synergistic effects on cell apoptosis and cell cycle arrest. The endoplasmic reticulum stress pathway-related proteins were significantly upregulated after the combination treatment of β-elemene and cisplatin (p < 0.05). Conclusion: β-Elemene enhances the antitumor activity of cisplatin in 5-8F cells via a mechanism involving the endoplasmic reticulum stress pathway. Thus, β-elemene is a potential tumor-suppressive agent in the clinical management of nasopharyngeal carcinoma