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RISS 인기검색어
- 검색키워드
- 저자 : Dongsheng Shen (검색결과 5 건)
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Adsorption properties of Friedel’s salt for the nitrate in the landfill
Dongsheng Shen,Jun Yao,Qingna Kong,Huayue Zhu,Zhen Zhang 한국화학공학회 2016 Korean Journal of Chemical Engineering Vol.33 No.2
Adsorption characteristics of nitrate on Friedel’s salt under the landfill circumstance were investigated to explore the effect of Friedel’s salt on the migration of nitrate in the landfill. Friedel’s salt was synthesized by a coprecipitation method and characterized by XRD and FTIR spectroscopy. The kinetics and isotherm of the adsorption were studied. The effect of the variation of landfill circumstance on the adsorption was also discussed. The result showed that the adsorption capacity of Friedel’s salt for nitrate was 2.494mg g−1. The adsorption process was exothermic and could be well described by pseudo-second-order kinetics and Langmuir-Freundlich equation. Cl− could enhance the adsorption, while SO4 2−, PO4 3− and organic matter could restrict the adsorption. The results suggested that the migration of nitrate in the landfill could be altered by Friedel’s salt, which was related to the variation of the landfill circumstance.
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The vertical distribution and temporal occurrence of three types of rice planthoppers in Shanghai
Wang Dongsheng,Wu Xiangwen,Yuan Yongda,Zhang Tianshu,Shen Huimei,Du Xingbin,Teng Haiyuan,Chang Xiaoli 한국곤충학회 2022 Entomological Research Vol.52 No.1
In this study, we investigated the dynamic occurrence and vertical distribution of three types of rice planthoppers (Nilaparvata lugens, Sogatella furcifera,and Laodelphax striatellus) in Shanghai, China. Our results showed that S. furcifera and L. striatellus infested the lower part of rice plants in the early development stage, S. furcifera and L. striatellus inhabited every part of rice in the middle development stage, and L. striatellus and N. lugens formicated in the upper part of the rice plant in the posterior development stage. The populations of rice planthoppers were larger in July and September, Where more than 600 adult and nymphal planthoppers, per a hundred hills of rice, were found in late July, and out of the 600, the majority were the nymphs of S. furcifera and L. striatellus. S. furcifera was mainly found from July to October, L. striatellus during the rice development, and N. lugens after September, during which their maximal individual number, per a hundred hills of rice, was 480, 220, less than 50, respectively. In addition, our results showed that adult rice planthoppers were mostly observed from late August to mid-October with the highest population being found during mid to late September. The adult S. furcifera, L. striatellus,andN. lugens were mostly observed in August and September, from August to October, and past mid-September, respectively. Moreover, the number of adult L. striatellus that were sticking to yellow sticky card was significantly higher than that of S. furcifera and N. lugens.
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Jianlong Yin,Jing Yu,Cheng Lou,Dongsheng Li,Xiaoyan Shen,Ming Li 한국정밀공학회 2023 International Journal of Precision Engineering and Vol.24 No.2
In an aerostatic restrictor, the presence of friction between the high-pressure air and the aerostatic restrictor wall can lead to non-uniform pressure and temperature distributions of the lubricating air film, which will affect the aerostatic restrictor performance. Therefore, explicating the pressure and temperature distributions of the lubricating air film could help to improve the characteristics and performance of the aerostatic restrictor. In this study, a theoretical model is established for the pressure and temperature distributions in the aerostatic restrictor with double U-shaped pressure-equalizing grooves, which is then compared with simulations, and finally verified by experiments. The results indicate the following. (1) The parameter distributions of the aerostatic restrictor’s air film are affected by the pressure-equalizing grooves and the orifice. (2) The air film parameter distributions are affected by the air source pressure and air film thickness. (3) The air film parameter distribution characteristics obtained from theoretical calculations, simulations, and experiments are consistent, indicating that the theoretical model is effective for studying the flow field of lubricating air film in the aerostatic restrictor. This model can also provide a theoretical basis for designing the orifice and pressure-equalizing grooves of the aerostatic restrictor, as well as selecting the air source pressure and air film thickness.
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Sun Feng,Li Na,Wang Lijia,Feng Huajun,Shen Dongsheng,Wang Meizhen 한국미생물학회 2020 The journal of microbiology Vol.58 No.11
The stabilization of quorum sensing (QS) is vital for bacterial survival in various environments. Although the mechanisms of QS stabilization in certain conditions have been well studied, the impact of environmental factors has received much less attention. In this study, we show that the supplementation of 25 μM iron in competition experiments and 50 μM in evolution experiments to casein growth cultures significantly increased the possibility of population collapse by affecting elastase production. However, the expression of lasI and lasR remained constant regardless of iron concentration and hence this effect was not through interference with the LasIR circuit, which mainly regulates the secretion of elastase in Pseudomonas aeruginosa. However, the expression of rhlR was significantly inhibited by iron treatment, which could affect the production of elastase. Further, based on both reverse transcription quantitative polymerase chain reaction and gene knock-out assays, we show that iron inhibits the transcription of ppyR and enhances the expression of mexT, both of which decrease elastase production and correspondingly interfere with QS stabilization. Our findings show that environmental factors can affect the genes of QS circuits, interfering with QS stabilization. These findings are not only beneficial in understanding the mechanistic effect of iron on QS stabilization, but also demonstrate the complexity of QS stabilization by linking non-QS-related genes with QS traits.
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A common evolutionary pathway for maintaining quorum sensing in Pseudomonas aeruginosa
Bai-min Lai,Hui-cong Yan,Mei-zhen Wang,Na Li,Dongsheng Shen 한국미생물학회 2018 The journal of microbiology Vol.56 No.2
In the bacterium Pseudomonas aeruginosa, the synthesis and secretion of extracellular protease is a typical cooperative behavior regulated by quorum sensing. However, this type of cooperative behavior is easily exploited by other individuals who do not synthesize public goods, which is known as the “tragedy of the commons”. Here P. aeruginosa was inoculated into casein media with different nitrogen salts added. In casein broth, protease (a type of public good) is necessary for bacterial growth. After 30 days of sequential transfer, some groups propagated stably and avoided “tragedy of the commons”. The evolved cooperators who continued to synthesize protease were isolated from these stable groups. By comparing the characteristics of quorum sensing in these cooperators, an identical evolutionary pattern was found. A variety of cooperative behaviors regulated by quorum sensing, such as the synthesis and secretion of protease and signals, were significantly reduced during the process of evolution. Such reductions improved the efficiency of cooperation, helping to prevent cheating. In addition, the production of pyocyanin, which is regulated by the RhlIR system, increased during the process of evolution, possibly due to its role in stabilizing the cooperation. This study contributes towards our understanding of the evolution of quorum sensing of P. aeruginosa.
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