The temporal and spatial growth behaviour of protein crystals, subject to different cooling strategies in protein crystallisation was investigated. Although the impact of temperature and cooling rate on crystal growth...The temporal and spatial growth behaviour of protein crystals, subject to different cooling strategies in protein crystallisation was investigated. Although the impact of temperature and cooling rate on crystal growth of small molecules was well documented, much less has been reported on their impact on the crystallisation of proteins. In this paper, an experimental set-up is configured to carry out such a study which involves an automatic temperature controlled hot-stage crystalliser fitted with a real-time imaging system. Linbro parallel crystallisation experiments(24-well plate) were also conducted to find the suitable initial conditions to be used in the hot-stage crystallisation experiments, including the initial concentration of HEW lysozyme solutions, precipitate concentration and pH value. It was observed that fast cooling rates at the early stage led to precipitates while slow cooling rates produced crystal nuclei, and very slow cooling rates, much smaller than for small molecules are critical to the growth of the nuclei and the crystals to a desired shape. The interesting results provide valuable insight as well as experimental proof of the feasibility and effectiveness of cooling as a means for achieving controlled protein crystallisation, compared with the evaporation approach which was widely used to grow single large crystals for X-ray diffraction study. Since cooling rate control can be easily achieved and has good repeatability, it suggests that large-scale production of protein crystals can be effectively achieved by manipulating cooling rates.展开更多
In order to get 2-chloro-4,6-dinitroresocinol(CDNR) with high purity,which influences the synthesis of 4,6-diaminoresorcinol dihydrochloride,the solubility of CDNR in various solvents was measured by laser method and ...In order to get 2-chloro-4,6-dinitroresocinol(CDNR) with high purity,which influences the synthesis of 4,6-diaminoresorcinol dihydrochloride,the solubility of CDNR in various solvents was measured by laser method and ethanol was chosen as the solvent.The recrystallization process of CDNR was investigated and crystallizing parameters such as cooling rate,temperature and time were discussed.Experimental results show that the time and temperature of crystallization greatly affect the yield and a higher yield can be received at-8 ℃ for 5 h.Slow cooling rate is helpful to the crystallization of CDNR,and the mechanical stirring or ultrasonic treatment can increase the yield and the purity of CDNR.展开更多
An A1-5.8Mg-0.4Mn-0.35（Sc＋Zr） （mass fraction, %） alloy sheet was prepared using water chilling copper mould ingot metallurgy processing which was protected by active flux. The influence of stabilizing annealing o...An A1-5.8Mg-0.4Mn-0.35（Sc＋Zr） （mass fraction, %） alloy sheet was prepared using water chilling copper mould ingot metallurgy processing which was protected by active flux. The influence of stabilizing annealing on mechanical properties and microstructure of the cold rolling sheet was studied. The results show that the strength and hardness of the alloy decrease, while the elongation increases with increasing the stabilizing annealing temperature. With the increase of stabilizing annealing time, the strength and hardness of the alloy drop slightly but its ductility exhibits no change. Partial recovery and recrystallization orderly occur with the increase of annealing temperature during stabilizing treatment. Only different degrees of recovery occur in the alloys annealed below 400 ℃ for 1 h. Partial recrystallization occurs after annealed at 450 ℃ for 1 h. By annealing at 300 ℃ for 1 h, the alloy can obtain the optimum application values of δb, δ0.2 and δ, which are 436 MPa, 327 MPa and 16.7%, respectively.展开更多
基金Supported by the China One Thousand Talent Scheme,the National Natural Science Foundation of China under its Major Research Scheme of Meso-scale Mechanism and Control in Multi-phase Reaction Processes(91434126)the Natural Science Foundation of Guangdong Province(2014A030313228)+1 种基金benefited from early work funded by UK Engineering and Physical Science Research Council(EP/H008012/1EP/H008853/1)
文摘The temporal and spatial growth behaviour of protein crystals, subject to different cooling strategies in protein crystallisation was investigated. Although the impact of temperature and cooling rate on crystal growth of small molecules was well documented, much less has been reported on their impact on the crystallisation of proteins. In this paper, an experimental set-up is configured to carry out such a study which involves an automatic temperature controlled hot-stage crystalliser fitted with a real-time imaging system. Linbro parallel crystallisation experiments(24-well plate) were also conducted to find the suitable initial conditions to be used in the hot-stage crystallisation experiments, including the initial concentration of HEW lysozyme solutions, precipitate concentration and pH value. It was observed that fast cooling rates at the early stage led to precipitates while slow cooling rates produced crystal nuclei, and very slow cooling rates, much smaller than for small molecules are critical to the growth of the nuclei and the crystals to a desired shape. The interesting results provide valuable insight as well as experimental proof of the feasibility and effectiveness of cooling as a means for achieving controlled protein crystallisation, compared with the evaporation approach which was widely used to grow single large crystals for X-ray diffraction study. Since cooling rate control can be easily achieved and has good repeatability, it suggests that large-scale production of protein crystals can be effectively achieved by manipulating cooling rates.
基金Sponsored by the Hi-Tech Research and Development Program of China(Grant No.2002AA305109)
文摘In order to get 2-chloro-4,6-dinitroresocinol(CDNR) with high purity,which influences the synthesis of 4,6-diaminoresorcinol dihydrochloride,the solubility of CDNR in various solvents was measured by laser method and ethanol was chosen as the solvent.The recrystallization process of CDNR was investigated and crystallizing parameters such as cooling rate,temperature and time were discussed.Experimental results show that the time and temperature of crystallization greatly affect the yield and a higher yield can be received at-8 ℃ for 5 h.Slow cooling rate is helpful to the crystallization of CDNR,and the mechanical stirring or ultrasonic treatment can increase the yield and the purity of CDNR.
基金Project(2006AA03Z523)supported by the National High Technology Research and Development Program of China
文摘An A1-5.8Mg-0.4Mn-0.35（Sc＋Zr） （mass fraction, %） alloy sheet was prepared using water chilling copper mould ingot metallurgy processing which was protected by active flux. The influence of stabilizing annealing on mechanical properties and microstructure of the cold rolling sheet was studied. The results show that the strength and hardness of the alloy decrease, while the elongation increases with increasing the stabilizing annealing temperature. With the increase of stabilizing annealing time, the strength and hardness of the alloy drop slightly but its ductility exhibits no change. Partial recovery and recrystallization orderly occur with the increase of annealing temperature during stabilizing treatment. Only different degrees of recovery occur in the alloys annealed below 400 ℃ for 1 h. Partial recrystallization occurs after annealed at 450 ℃ for 1 h. By annealing at 300 ℃ for 1 h, the alloy can obtain the optimum application values of δb, δ0.2 and δ, which are 436 MPa, 327 MPa and 16.7%, respectively.
