The aim of the present work was to design a bio-interactive implant surface by coating recombinant human dentin matrix protein 1 (hDMP1) onto titanium and to investigate the biological function of this material. Firstly, the plasmid containing the hDMP1 cDNA was constructed and hDMP1 was expressed, purified and characterized. Then, hDMP1 was coated onto the surface of Ti substrates via a biochemical technique and the procedure was divided into three steps: in the beginning, titanium was treated by regular polishing and denoted as Cp-Ti; then, Cp-Ti received alkaline and water treatment and was nominated as AW-Ti; finally, AW-Ti was coated with hDMP1 and referred to as hDMP1-Ti. The inserts of hDMP1 genes were detected by enzyme digestion as well as gel electrophoresis, and the complete nucleotide sequence of hDMP1 was tested. The purified recombinant hDMP1 was electrophoresed on a 10 % SDS-PAGE gel. Cp-Ti, AW-Ti and hDMP1-Ti were characterized by X-ray photoelectron spectroscope and water contact angles tests. The biological activity of MG63 cells cultured in the three groups was investigated by the cell attachment, proliferation and alkaline phosphatase activity assays. The results show that hDMP1 was successfully constructed and coated onto the titanium surface, and hDMP1-Ti had higher hydrophilicity than Cp-Ti. Compared with Cp-Ti and AW-Ti, hDMP1-Ti showed better in vitro bioactivity.

AVO characteristics were ambiguous in thin-layer interbed sandstones and mudstones of terrestrial facies of Daqing area. Described in this paper is the 3D AVO analysis and real examples in the Songzhan region in the north of the Songliao basin. The AVO responses of the Fuyu sandstone reservoir, obtained through special AVO processing and interpretation as well as the AVO forward modeling under the constraints of logging data, were evident in the Sheng-81 well. It was concluded that the Fuyu sandstone reservoir presented an AVO anomaly of "amplitudes increasing with offsets". At the same time, the deep volcanic reservoirs were ascertained and the channels of volcanic eruption were delineated at the intersections of faults in Sanzhao area, through a 3D AVO analysis, which coincided with the theory of geodynamics and tectonophysics.

With the development of the Chinese stock market and the continuous improvement of financial engineering technology, quantitative investment represented by the multi-factor stock selection strategy has been developing and growing in the Chinese stock market. This paper takes the quarterly data of the China Securities New Energy Vehicle Index from January 2017 to March 2021 as the research object, uses the Fama-Macbeth test to select factors, and constructs the regression equation based on the regression method. The regression equation is used to predict the stock return rate of the next quarter through the factor data of each quarter in 2020. The top 7 stocks with returns are selected to construct the investment portfolio in the way of equal-weighted capital allocation, and the investment portfolio is updated quarterly. Through the empirical test, this paper mainly draws the following three conclusions: First, the driving factors of stock return in the new energy vehicle industry mainly include the ratio of long-term debt to working capital (LTDWC), total profit growth rate (TPG), price/earnings to growth ratio (PEG), and equity turnover ratio (ET); secondly, the portfolio return based on the stock selection model in this paper is higher than the average level of the industry, and the investment return obtained is stable, suitable for investment targets; third, the new energy vehicle industry is in a period of rapid development, and the portfolio return rate is higher than the average level of A-share market. Therefore, it has huge potential investment value. This paper provides suggestions and solutions for investors' stock investment in the new energy vehicle industry.

No abstract

No abstract