The influence of water on protein conformation was investigated by simulating the molecular dynamics of a model protein lysozyme in different water systems.The lysozyme-water system with TIP3P water model and lysozyme...The influence of water on protein conformation was investigated by simulating the molecular dynamics of a model protein lysozyme in different water systems.The lysozyme-water system with TIP3P water model and lysozyme-water cluster system with six-ring water model were evaluated.In addition,the radial distribution function of solvent around lysozyme was calculated.It is found that the distribution of water molecules around lysozyme is similar to that of water clusters.The analyses of dihedral angles and disulfide bonds of lysozyme show that the conformation of lysozyme is severely damaged in the lysozyme-water cluster system compared with that in the lysozyme-water system.This difference can be attributed to the formation of larger number of intermolecular hydrogen bonds between lysozyme and water cluster.It is in agreement with the analysis that water clusters can change the degree of denaturation in the process of heat denaturation of lysozyme.展开更多
为评估处置库的安全性,核素化学形态信息是准确预测核素的运移行为研究的前提。鉴于我国核能工业的迅速发展以及建立环境中核素的确认需求,在我国开展处置库周围核素的化学形态研究具有十分重要的意义。针对地下水中元素种态分布的研究...为评估处置库的安全性,核素化学形态信息是准确预测核素的运移行为研究的前提。鉴于我国核能工业的迅速发展以及建立环境中核素的确认需求,在我国开展处置库周围核素的化学形态研究具有十分重要的意义。针对地下水中元素种态分布的研究需求,以JAVA为开发工具、MySQL作为数据库、Tomcat为容器,开发了一套B/S架构的元素种态分布模拟软件。针对模拟计算中遇到的化学反应平衡非线性方程组求解收敛困难的问题,引入了根据化学反应势能求解的方法和反应因子控制迭代步长,实现了对化学反应非线性方程快速地求解,并可拓展多相平衡计算。以塔木素地下水中镎为考察对象,利用所开发化学形态模拟软件(simulation software on chemical species,SSCS)计算环境中镎的形态和量,并对比PHREEQC的计算结果,相对偏差在10%以内,针对环境中痕量元素的分布,提供了理论计算的解决方案。展开更多
建立了高效液相色谱-电喷雾-四级杆飞行时间质谱(HPLC-ESI-Q-TOF)分析高粱多酚的方法。色谱条件为:流动相A为体积分数为0.1%甲酸的H_(2)O,流动相B为体积分数为0.1%甲酸的乙腈,流动相梯度A 0~20 min 85%~40%、20~23 min 40%~10%、23~28 m...建立了高效液相色谱-电喷雾-四级杆飞行时间质谱(HPLC-ESI-Q-TOF)分析高粱多酚的方法。色谱条件为:流动相A为体积分数为0.1%甲酸的H_(2)O,流动相B为体积分数为0.1%甲酸的乙腈,流动相梯度A 0~20 min 85%~40%、20~23 min 40%~10%、23~28 min 10%~10%、28~30 min 10%~85%、30~37 min 85%~85%;流速0.2 mL/min,进样量5μL,柱温30℃。质谱条件为:负离子模式下,毛细管电压2.6 kV,干燥气温度180℃,干燥气流量6 L/min,辅助气压力0.08 MPa,质荷比采集范围100~1200 m/z,碰撞能量为35 eV。对5种高粱所含的多酚类物质进行分析,共鉴定出20种高粱多酚,包括10种酚酸类物质、3种原花青素、7种酚酸类衍生物。展开更多
Zirconyl-molybdopyrophosphate-tributyl phosphate （ZMPP-TBP） was a novel organic-inorganic composite adsorbent prepared by co-precipitation method and used in the adsorption of uranium from aqueous solution in batch ...Zirconyl-molybdopyrophosphate-tributyl phosphate （ZMPP-TBP） was a novel organic-inorganic composite adsorbent prepared by co-precipitation method and used in the adsorption of uranium from aqueous solution in batch adsorption experiments The as-obtained product was characterized using SEM, energy dispersive X-ray spectroscopy （EDX）, XRD and BET-N2 ad- sorption measurements. The study had been conducted to investigate the effects of solution pH, temperature, contact time, ini- tial concentration and coexisting ions. A maximum removal of 99.31% was observed for an initial concentration 5 mg/L, at pH 6.0 and an adsorbent dose of 1.0 g/L. The isothermal data were fitted with both Langmuir and Freundlich equations, but the data fitted the former better than the latter. According to the evaluation using the Langmuir equation, the maximum adsorption capacity of uranium （VI） was 196.08 mg/g at 293 K and pH 6.0. The pseudo-first-order kinetic model and pseudo-second-order kinetic model were used to describe the kinetic data, and the pseudo-second-order kinetic model was better. The thermody- namic parameter AG was calculated, the negative AG values of uranium （VI） at different temperature showed that the adsorption process was spontaneous. The good reusability of ZMPP-TBP also indicated that the ZMPP-TBP was a very promising adsorbent for uranium adsorption from aqueous solution.展开更多
The acid-base titration,atomic force microscopy(AFM),contact angle technique,energy dispersive X-ray(EDX)and electron probe microanalysis(EPMA)were performed to check the existence of the gel-layer on the chitosan sur...The acid-base titration,atomic force microscopy(AFM),contact angle technique,energy dispersive X-ray(EDX)and electron probe microanalysis(EPMA)were performed to check the existence of the gel-layer on the chitosan surface after it was dipped in aqueous TPAOH solution as well as in TS-1 synthesis solution.The evolution of TS-1 monolayer and multi-layered film on the chitosan surface was studied using SEM imaging at different stages during hydrothermal reactions.Experimental evidence for the formation mechanism of supported zeolite films and membranes revealed that a gel-layer enriched with TPA cations and TS-1 precursors was first formed on the chitosan surface,followed by the nucleation within the gel-layer especially on the chitosan surface.The nuclei formed on the chitosan surface were further transformed into crystalline particles and TS-1 crystal grains.The nuclei beyond the chitosan surface subsequently grew up,leading to the formation of multi-layered TS-1 film with preferential b-orientation.The result is significant for engineering the microstructure of supported zeolite films and membranes in hydrothermal reactions.展开更多
基金Supported by National Natural Science Foundation of China (No. 20676094)
文摘The influence of water on protein conformation was investigated by simulating the molecular dynamics of a model protein lysozyme in different water systems.The lysozyme-water system with TIP3P water model and lysozyme-water cluster system with six-ring water model were evaluated.In addition,the radial distribution function of solvent around lysozyme was calculated.It is found that the distribution of water molecules around lysozyme is similar to that of water clusters.The analyses of dihedral angles and disulfide bonds of lysozyme show that the conformation of lysozyme is severely damaged in the lysozyme-water cluster system compared with that in the lysozyme-water system.This difference can be attributed to the formation of larger number of intermolecular hydrogen bonds between lysozyme and water cluster.It is in agreement with the analysis that water clusters can change the degree of denaturation in the process of heat denaturation of lysozyme.
文摘为评估处置库的安全性,核素化学形态信息是准确预测核素的运移行为研究的前提。鉴于我国核能工业的迅速发展以及建立环境中核素的确认需求,在我国开展处置库周围核素的化学形态研究具有十分重要的意义。针对地下水中元素种态分布的研究需求,以JAVA为开发工具、MySQL作为数据库、Tomcat为容器,开发了一套B/S架构的元素种态分布模拟软件。针对模拟计算中遇到的化学反应平衡非线性方程组求解收敛困难的问题,引入了根据化学反应势能求解的方法和反应因子控制迭代步长,实现了对化学反应非线性方程快速地求解,并可拓展多相平衡计算。以塔木素地下水中镎为考察对象,利用所开发化学形态模拟软件(simulation software on chemical species,SSCS)计算环境中镎的形态和量,并对比PHREEQC的计算结果,相对偏差在10%以内,针对环境中痕量元素的分布,提供了理论计算的解决方案。
文摘建立了高效液相色谱-电喷雾-四级杆飞行时间质谱(HPLC-ESI-Q-TOF)分析高粱多酚的方法。色谱条件为:流动相A为体积分数为0.1%甲酸的H_(2)O,流动相B为体积分数为0.1%甲酸的乙腈,流动相梯度A 0~20 min 85%~40%、20~23 min 40%~10%、23~28 min 10%~10%、28~30 min 10%~85%、30~37 min 85%~85%;流速0.2 mL/min,进样量5μL,柱温30℃。质谱条件为:负离子模式下,毛细管电压2.6 kV,干燥气温度180℃,干燥气流量6 L/min,辅助气压力0.08 MPa,质荷比采集范围100~1200 m/z,碰撞能量为35 eV。对5种高粱所含的多酚类物质进行分析,共鉴定出20种高粱多酚,包括10种酚酸类物质、3种原花青素、7种酚酸类衍生物。
基金supported by the National Natural Science Foundation of China (21276193)the National High-Tech Research & Development Program of China (863 Program+2 种基金 2012AA063504)the Tianjin Natural Science Foundation (2013F1-0033)Project of Ocean with Scientific Technology in Tianjin (KJXH2011-10)
文摘Zirconyl-molybdopyrophosphate-tributyl phosphate （ZMPP-TBP） was a novel organic-inorganic composite adsorbent prepared by co-precipitation method and used in the adsorption of uranium from aqueous solution in batch adsorption experiments The as-obtained product was characterized using SEM, energy dispersive X-ray spectroscopy （EDX）, XRD and BET-N2 ad- sorption measurements. The study had been conducted to investigate the effects of solution pH, temperature, contact time, ini- tial concentration and coexisting ions. A maximum removal of 99.31% was observed for an initial concentration 5 mg/L, at pH 6.0 and an adsorbent dose of 1.0 g/L. The isothermal data were fitted with both Langmuir and Freundlich equations, but the data fitted the former better than the latter. According to the evaluation using the Langmuir equation, the maximum adsorption capacity of uranium （VI） was 196.08 mg/g at 293 K and pH 6.0. The pseudo-first-order kinetic model and pseudo-second-order kinetic model were used to describe the kinetic data, and the pseudo-second-order kinetic model was better. The thermody- namic parameter AG was calculated, the negative AG values of uranium （VI） at different temperature showed that the adsorption process was spontaneous. The good reusability of ZMPP-TBP also indicated that the ZMPP-TBP was a very promising adsorbent for uranium adsorption from aqueous solution.
基金supported by the National Natural Science Foundation of China(20636030,20776100 and 20776108)
文摘The acid-base titration,atomic force microscopy(AFM),contact angle technique,energy dispersive X-ray(EDX)and electron probe microanalysis(EPMA)were performed to check the existence of the gel-layer on the chitosan surface after it was dipped in aqueous TPAOH solution as well as in TS-1 synthesis solution.The evolution of TS-1 monolayer and multi-layered film on the chitosan surface was studied using SEM imaging at different stages during hydrothermal reactions.Experimental evidence for the formation mechanism of supported zeolite films and membranes revealed that a gel-layer enriched with TPA cations and TS-1 precursors was first formed on the chitosan surface,followed by the nucleation within the gel-layer especially on the chitosan surface.The nuclei formed on the chitosan surface were further transformed into crystalline particles and TS-1 crystal grains.The nuclei beyond the chitosan surface subsequently grew up,leading to the formation of multi-layered TS-1 film with preferential b-orientation.The result is significant for engineering the microstructure of supported zeolite films and membranes in hydrothermal reactions.
