China's high-speed socioeconomic development has been characterized by rapid urbanization and a series of ecological environment issues, especially air pollution. This paper proposed a comprehensive indicator system for the evaluation of urbanization and the air environment in Wuhan, a metropolis in central China, and then investigated the relationship between urbanization and the air environment from the perspective of coupling coordination theory. Furthermore, a coupling coordination degree model (CCDM) was constructed to estimate the relationship by using panel data collected from 1996-2013. The results showed the following: (1) Spatial urbanization and air environment quality make the greatest contributions to the compound system compared to other first grade indicators, indicating that they are critical factors to consider when the government is making relevant decisions about urban sprawl. (2) The comprehensive level of the air environment initially decreased from 1996-1998 and then increased with fluctuations in Wuhan, with several inflection points, meaning that the variation process of the air environment is unstable and repetitive, and efforts to improve the air environment must persist over a long period of time. Lastly, (3) the degree of coordinated coupling between urbanization and the air environment exhibited an S-shaped curve, indicating that Wuhan changed from having slightly unbalanced development to barely balanced development and then entered into a OPEN ACCESSAtmosphere 2015, 6 1540 period of superiorly balanced development, with the air environment lagging. Thus, the ambient urban air quality has been subject to great pressure, and the government should continue to take effective action to improve it.

The repair of large-area irregular bone defects is one of the complex problems in orthopedic clinical treatment. The bone repair scaffolds currently studied include electrospun membrane, hydrogel, bone cement, 3D printed bone tissue scaffolds, etc., among which 3D printed polymer-based scaffolds Bone scaffolds are the most promising for clinical applications. This is because 3D printing is modeled based on the im-aging results of actual bone defects so that the printed scaffolds can perfectly fit the bone defect, and the printed components can be adjusted to promote Osteogenesis. This review introduces a variety of 3D printing technologies and bone healing processes, reviews previous studies on the characteristics of commonly used natural or synthetic polymers, and clinical applications of 3D printed bone tissue scaffolds, analyzes and elaborates the characteristics of ideal bone tissue scaffolds, from t he progress of 3D printing bone tissue scaffolds were summarized in many aspects. The challenges and potential prospects in this direction were discussed.

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Aberrant expression of cell division cycle 20 (CDC20) is associated with malignant progression and poor prognosis in various types of cancer. The development of specific CDC20 inhibitors may be a novel strategy for the treatment of cancer with elevated expression of CDC20. The aim of the current study was to elucidate the role of CDC20 in cancer cell invasiveness and to identify novel natural inhibitors of CDC20. The authors found that CDC20 knockdown inhibited the migration of chemoresistant PANC-1 pancreatic cancer cells and the metastatic MDA-MB-231 breast cancer cell line. By contrast, the overexpression of CDC20 by plasmid transfection promoted the metastasizing capacities of the PANC-1 cells and MCF-7 breast cancer cells. It was also identified that a triterpene mixture extracted from the mushroom Poria cocos (PTE), purified triterpenes dehydropachymic acid, and polyporenic acid C (PPAC) downregulated the expression of CDC20 in PANC-1 cells dose-dependently. Migration was also suppressed by PTE and PPAC in a dose-dependent manner, which was consistent with expectations. Taken together, the present study is the first, to the best of our knowledge, to demonstrate that CDC20 serves an important role in cancer metastasis and that triterpenes from P. cocos inhibit the migration of pancreatic cancer cells associated with CDC20. Further investigations are in progress to investigate the specific mechanism associated with CDC20 and these triterpenes, which may have future potential use as natural agents in the treatment of metastatic cancer.

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