6 research outputs found
The Political Economy of the Automobile Industry Development in China
This paper analyses the political economy of developing the modern Chinese automobile industry. By using qualitative research method, especially case study, and developmental rent management analysis framework, the author analyzed the development in three different time periods since the Chinese economic reform in 1978. Case studies of learning period, developing period and new Chinese owned enterprises after joining WTO presented different policies and rent management strategies arranged by the state to industrialize and develop the modern Chinese automobile industry. Although there are failures involved in the arrangement, China finally industrialized and developed its modern automobile industry and became the world\u27s largest automobile manufacturing country since 2009. This thesis provided evidences that developing countries cannot easily develop their own industry successfully without the well-designed interventions from the state
Study of imbibition in various geometries using phase field method
Phase field method has been widely utilized to study multiphase flow problems, but has seldom been applied to the study of imbibition. Previous methods used to simulate imbibition, such as moving mesh method, need to specify capillary pressure as a boundary condition a priori, whereas phase field method can calculate capillary pressure automatically for various geometries. Therefore, phase field method would be a versatile tool for the study of imbibition in various geometries. In this paper, phase field method is employed to solve dynamical imbibition problem in various geometries, including straight tube, conical tube and structures in which the topology changes. The variation of the imbibition height with respect to time from phase field simulation is verified with theoretical predictions from Lucas-Washburn law in a straight capillary tube with three gravitational scenarios. In addition, the capillary pressure and velocity field are found to be consistent with Laplace-Young equation and Hagen-Poiseuille equation in various geometries. The applicability and accuracy of the phase field method for the study of imbibition in structures with changing topology are also discussed.Cited as: Xiao, J., Luo, Y., Niu, M., Wang, Q., Wu, J., Liu, X., Xu, J. Study of imbibition in various geometries using phase field method. Capillarity, 2019, 2(4): 57-65, doi: 10.26804/capi.2019.04.0
Figure_4A.csv
Size exclusion chromatography of 100 μg/ml fluorescein-labelled high-molecular-weight hyaluronan (HMW-HA, ~800 kDa, Carbosynth) or hyaluronan 22-mer (dp22, ~5 kDa, Iduron), and of 100 μg/ml fluorescein-labelled HMW-HA incubated overnight with 100 μg/ml transmembrane protein 2 ectodomain (sTMEM2) or sperm hyaluronidase (HAase, Sigma-Aldrich, H3884). The reaction buffer was 100 mM MES, pH 6.0, 1 mM CaCl2.</p
Figure_4B.csv
Ultrafiltration (molecular weight cut-off 50 kDa) of 0.1 μg/ml fluorescein-labelled high-molecular-weight hyaluronan (HMW-HA, ~800 kDa, Carbosynth) incubated overnight with 100 μg/ml transmembrane protein 2 ectodomain (sTMEM2) or sperm hyaluronidase (HAase, Sigma-Aldrich, H3884). The reaction buffer was 100 mM MES, pH 6.0, 1 mM CaCl2. The mock condition contained an irrelevant protein at 100 μg/ml (Endo180 domains 1-4).</p
Structure of the transmembrane protein 2 (TMEM2) ectodomain and its apparent lack of hyaluronidase activity [version 2; peer review: 2 approved]
Background: Hyaluronic acid (HA) is a major polysaccharide component of the extracellular matrix. HA has essential functions in tissue architecture and the regulation of cell behaviour. HA turnover needs to be finely balanced. Increased HA degradation is associated with cancer, inflammation, and other pathological situations. Transmembrane protein 2 (TMEM2) is a cell surface protein that has been reported to degrade HA into ~5 kDa fragments and play an essential role in systemic HA turnover. Methods: We produced the soluble TMEM2 ectodomain (residues 106-1383; sTMEM2) in human embryonic kidney cells (HEK293) and determined its structure using X-ray crystallography. We tested sTMEM2 hyaluronidase activity using fluorescently labelled HA and size fractionation of reaction products. We tested HA binding in solution and using a glycan microarray. Results: Our crystal structure of sTMEM2 confirms a remarkably accurate prediction by AlphaFold. sTMEM2 contains a parallel β-helix typical of other polysaccharide-degrading enzymes, but an active site cannot be assigned with confidence. A lectin-like domain is inserted into the β-helix and predicted to be functional in carbohydrate binding. A second lectin-like domain at the C-terminus is unlikely to bind carbohydrates. We did not observe HA binding in two assay formats, suggesting a modest affinity at best. Unexpectedly, we were unable to observe any HA degradation by sTMEM2. Our negative results set an upper limit for kcat of approximately 10-5 min-1. Conclusions: Although sTMEM2 contains domain types consistent with its suggested role in TMEM2 degradation, its hyaluronidase activity was undetectable. HA degradation by TMEM2 may require additional proteins and/or localisation at the cell surface