Protein refolding is a key step for the production of recombinant proteins, especially at large scales, and usually their yields are very low. Chromatographic-based protein refolding techniques have proven to be superior to conventional dilution refolding methods. High refolding yield can be achieved using these methods compared with dilution refolding of proteins. In this work, recombinant human tumor necrosis factor-α (rhTNF-α) from inclusion bodies expressed in Escherichia coli was renatured with simultaneous purification by ion exchange chromatography with a DEAE Sepharose FF column. Several chromatographic parameters influencing the refolding yield of the denatured/reduced rhTNF-α, such as the urea concentration, pH value and concentration ratio of glutathione/oxidized glutathione in the mobile phase, were investigated in detail. Under optimal conditions, rhTNF-α can be renatured and purified simultaneously within 30 min by one step. Specific bioactivity of 2.18 × 10(8) IU/mg, purity of 95.2% and mass recovery of 76.8% of refolded rhTNF-α were achieved. Compared with the usual dilution method, the ion exchange chromatography method developed here is simple and more effective for rhTNF-α refolding in terms of specific bioactivity and mass recovery.
The marriage of catalyst nanoparticles and mesoporous supports brings exciting new opportunities in the field of catalysis, which provides the ability to create advanced nanoporous catalysts for a wide range of catalytic processes. It has been found that not only the features of mesoporous supports, such as, surface areas, mesostructures, and pore sizes, are critical for the catalytic performances, but also the unique properties of catalyst nanoparticles, including dispersion, particle size, and loading amount, play critical roles in determining catalytic performance. Those aspects have been discussed partly in previous reviews, but a comprehensive overview on the basic design principles and synthetic methods for the marriage of catalyst nanoparticles and mesoporous supports is still lacking. In this review, the recent progresses in the fabrication of advanced catalysts by incorporation of catalyst nanoparticles into mesoporous supports are summarized. First, the synthetic strategies for the controllable synthesis are reviewed. At the same time, the corresponding chemical‐/physically properties of the resultant supported mesoporous catalysts are highlighted. After that, the catalytic performances of the resultant mesoporous catalysts in the thermal catalysis, photocatalysis, and electrocatalysis are discussed. Moreover, the research challenges and perspectives in this field are assessed.
At present, Zhoushan's natural population growth rate is the lowest in Zhejiang, and the ageing in the province is the most serious. From a macro point of view, Zhoushan has to occupy the advantage in the problem of "graduates stay in Zhoushan" to relieve the pressure and sense of urgency brought by the considerable decline in the natural growth rate and to pave the way for the future from the development vision of the strategy of strengthening the country with talent. This study first the qualitative research, the method of research, using the literature analysis, based on the previous analysis of employment impact factors, through classification, screening and sorting, the following final summary and summary of the following more typical and universal factors: urban factors; Natural factors; employment economy; emotional factors; family economy. Then, this study adopts a quantitative analysis method based on the above five research objectives and factors. This study designs a high correlation with each factor forms a questionnaire through cluster analysis to check the correlation of factors and problems and optimizes and modifies the factor classification and problem set to find out the correlation between five factors and the influence of five factors for Zhoushan students. After that, this study draws the corresponding conclusion, puts forward perfect measures and a more feasible scheme, and establishes the corresponding structure equation model.
This article used SATI3.2 software to process 488 documents related to international students' education from China Knowledge Network Database (CNKI). The collected data was from 163 core Chinese journals, published from 2009 to 2022. By using the visualized data quantitatively, it presented the current status of the main research hotspots of international student education. The influence of international education on China's economy and the role of Chinese cultural communication will remain a hot research topic in the field. Countries along the Belt and Road are and will be the driving force for the increase of students studying in China. The population of international students is increasing sharply and their needs in hosting universities are getting diverse, however, international students in China are an understudied population, and more research needs to be done on this group. we suggested that Chinese scholars should gradually shift from focusing on policy to concentrating on international students themselves at Chinese universities.
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