On the line of multi-molecule-formed transition state mechanism,reactionof ClONO2 with HCl on ice surface was investigated with model system by theoretical ab initio calculations.In the gas phase,the barrier of reacti...On the line of multi-molecule-formed transition state mechanism,reactionof ClONO2 with HCl on ice surface was investigated with model system by theoretical ab initio calculations.In the gas phase,the barrier of reaction of ClONO2 with HCl is 240.2kJ·mol-1at MP2HF/6-31G(d) level.The barriers drop substantially with the involvement of water molecules. The barrier of reaction of ClONO2 with 2H2O·HCl is 4.6kJ·mol-1 at the same theoretical level which suggests that the reaction of ClONO2 with HcCl can occur readily on ice surface,. The detailed accont will be published in near future.展开更多
左旋苯丙胺(又称左苯丙胺,RAT)在临床上被用于治疗多种病症,作用在中枢神经细胞多巴胺受体上,同时它具有依赖性和成瘾性。为了探讨RAT被用作药物的药理和成瘾机制,本文用分子模拟获得RAT与多巴胺第三受体(D_3R)复合蛋白优化结构,并且采...左旋苯丙胺(又称左苯丙胺,RAT)在临床上被用于治疗多种病症,作用在中枢神经细胞多巴胺受体上,同时它具有依赖性和成瘾性。为了探讨RAT被用作药物的药理和成瘾机制,本文用分子模拟获得RAT与多巴胺第三受体(D_3R)复合蛋白优化结构,并且采用伞形样本平均力势(PMF)方法和卵磷脂脂质分子模拟生物膜,采用分子动力学模拟获得RAT在D_3R结构中分子通道运动轨迹和自由能变化。RAT通过D_3R结构中的功能分子通道,朝细胞外方向传输运动的自由能变化为91.4 k J?mol^(-1)。RAT通过D_3R结构中的保护分子通道,朝细胞双层膜方向传输运动的自由能变化为117.7 k J?mol^(-1)。自由能数值表明RAT分子更容易通过D_3R结构中的功能分子通道,发挥其功能作用,增大功能多巴胺分子的释放,导致包括依赖性和成瘾性多种功能效果。研究结果证明RAT被用作药物的药理和成瘾机制与它在多巴胺受体中的分子通道上传输动力学和机制有密切关联。展开更多
The authors have studied the spectroscopic characteristics and the fluorescence lifetime for the chloroplasts from spinach (Spinacia oleracea L.) and water hyacinth (Eichhornia crassipes (Mart) Solms.) plant leaves by...The authors have studied the spectroscopic characteristics and the fluorescence lifetime for the chloroplasts from spinach (Spinacia oleracea L.) and water hyacinth (Eichhornia crassipes (Mart) Solms.) plant leaves by absorption spectra, low temperature steady_state fluorescence spectroscopy and single photon counting measurement under the same conditions. The absorption spectra at room temperature for the spinach and water hyacinth chloroplasts are similar, which show that different plants can efficiently absorb light of same wavelength. The low temperature steady_state fluorescence spectroscopy for the water hyacinth chloroplast reveals a poor balance of photon quantum between two photosystems. The fluorescence decays in PSⅡ measured at the natural Q A state for the chloroplasts have been fitted by a three_exponential kinetic model. The slow lifetime fluorescence component is assigned to a collection of associated light harvesting Chl a/b proteins, the fast lifetime component to the reaction center of PSⅡ and the middle lifetime component to the delay fluorescence of recombination of P + 680 and Pheo -. The excited energy conversion efficiency (η) in PSⅡ RC is 87% and 91% respectively for the water hyacinth and spinach chloroplasts calculated on the 20 ps model. This interesting result is not consistent with what is assumed that the efficiency is 100% in PSⅡ RC. The results in this paper also present a support for the 20 ps electron transfer time constant in PSⅡ RC. On the viewpoint of excitation energy conversion efficiency, the growing rate for the water hyacinth plan is smaller than that for the spinach plant. But, authors' results show those plants can perform highly efficient transfer of photo_excitation energy from the light_harvesting pigment system to the reaction center (approximately 100%).展开更多
文摘On the line of multi-molecule-formed transition state mechanism,reactionof ClONO2 with HCl on ice surface was investigated with model system by theoretical ab initio calculations.In the gas phase,the barrier of reaction of ClONO2 with HCl is 240.2kJ·mol-1at MP2HF/6-31G(d) level.The barriers drop substantially with the involvement of water molecules. The barrier of reaction of ClONO2 with 2H2O·HCl is 4.6kJ·mol-1 at the same theoretical level which suggests that the reaction of ClONO2 with HcCl can occur readily on ice surface,. The detailed accont will be published in near future.
文摘左旋苯丙胺(又称左苯丙胺,RAT)在临床上被用于治疗多种病症,作用在中枢神经细胞多巴胺受体上,同时它具有依赖性和成瘾性。为了探讨RAT被用作药物的药理和成瘾机制,本文用分子模拟获得RAT与多巴胺第三受体(D_3R)复合蛋白优化结构,并且采用伞形样本平均力势(PMF)方法和卵磷脂脂质分子模拟生物膜,采用分子动力学模拟获得RAT在D_3R结构中分子通道运动轨迹和自由能变化。RAT通过D_3R结构中的功能分子通道,朝细胞外方向传输运动的自由能变化为91.4 k J?mol^(-1)。RAT通过D_3R结构中的保护分子通道,朝细胞双层膜方向传输运动的自由能变化为117.7 k J?mol^(-1)。自由能数值表明RAT分子更容易通过D_3R结构中的功能分子通道,发挥其功能作用,增大功能多巴胺分子的释放,导致包括依赖性和成瘾性多种功能效果。研究结果证明RAT被用作药物的药理和成瘾机制与它在多巴胺受体中的分子通道上传输动力学和机制有密切关联。
文摘The authors have studied the spectroscopic characteristics and the fluorescence lifetime for the chloroplasts from spinach (Spinacia oleracea L.) and water hyacinth (Eichhornia crassipes (Mart) Solms.) plant leaves by absorption spectra, low temperature steady_state fluorescence spectroscopy and single photon counting measurement under the same conditions. The absorption spectra at room temperature for the spinach and water hyacinth chloroplasts are similar, which show that different plants can efficiently absorb light of same wavelength. The low temperature steady_state fluorescence spectroscopy for the water hyacinth chloroplast reveals a poor balance of photon quantum between two photosystems. The fluorescence decays in PSⅡ measured at the natural Q A state for the chloroplasts have been fitted by a three_exponential kinetic model. The slow lifetime fluorescence component is assigned to a collection of associated light harvesting Chl a/b proteins, the fast lifetime component to the reaction center of PSⅡ and the middle lifetime component to the delay fluorescence of recombination of P + 680 and Pheo -. The excited energy conversion efficiency (η) in PSⅡ RC is 87% and 91% respectively for the water hyacinth and spinach chloroplasts calculated on the 20 ps model. This interesting result is not consistent with what is assumed that the efficiency is 100% in PSⅡ RC. The results in this paper also present a support for the 20 ps electron transfer time constant in PSⅡ RC. On the viewpoint of excitation energy conversion efficiency, the growing rate for the water hyacinth plan is smaller than that for the spinach plant. But, authors' results show those plants can perform highly efficient transfer of photo_excitation energy from the light_harvesting pigment system to the reaction center (approximately 100%).
