Polymeric perylene diimide(PDI)has been evidenced as a good candidate for photocatalytic water oxidation,yet the origin of the photocatalytic oxygen evolution activity remains unclear and needs further exploration.Her...Polymeric perylene diimide(PDI)has been evidenced as a good candidate for photocatalytic water oxidation,yet the origin of the photocatalytic oxygen evolution activity remains unclear and needs further exploration.Herein,with crystal and atomic structures of the self-assembled PDI revealed from the X-ray diffraction pattern,the electronic structure is theoretically illustrated by the first-principles density functional theory calculations,suggesting the suitable band structure and the direct electronic transition for efficient photocatalytic oxygen evolution over PDI.It is confirmed that the carbonyl O atoms on the conjugation structure serve as the active sites for oxygen evolution reaction by the crystal orbital Hamiltonian group analysis.The calculations of reaction free energy changes indicate that the oxygen evolution reaction should follow the reaction pathway of H_(2)O→^(*)OH→^(*)O→^(*)OOH→^(*)O_(2)with an overpotential of 0.81 V.Through an in-depth theoretical computational analysis in the atomic and electronic structures,the origin of photocatalytic oxygen evolution activity for PDI is well illustrated,which would help the rational design and modification of polymeric photocatalysts for efficient oxygen evolution.展开更多
目的以课题组纯化获得的蛋白样本为观察对象,对比原子力显微镜(atomic force microscope,AFM)及扫描电子显微镜(scanning electron microscope,SEM)的观察结果,并总结AFM观察生物大分子的主要问题和解决方法。方法将蛋白样本使用PBS稀释...目的以课题组纯化获得的蛋白样本为观察对象,对比原子力显微镜(atomic force microscope,AFM)及扫描电子显微镜(scanning electron microscope,SEM)的观察结果,并总结AFM观察生物大分子的主要问题和解决方法。方法将蛋白样本使用PBS稀释至15 nmol·L^(-1),分别固定于载玻片、硅片和云母片上烘干,制成固相观察样本,SEM样本在观察前镀铂,使用AFM及SEM观察蛋白质表面结构,计算样本高度,对比结果差异。结果带正电的蛋白样本在观察时由于AFM探针的斥力会向右偏移;云母片能很好地消除蛋白正电荷从而避免样本移动;PBS能为蛋白样本提供良好的稳定环境,但PBS盐结晶会干扰探针运行和成像清晰度;SEM样本需要镀铂后观察,无法达到AFM的精度。结论使用AFM和SEM均可在体外环境直接观察蛋白质结构,AFM能提供更高精度的观察结果;在蛋白样本稳定性允许的情况下首选超纯水为溶剂载体,乙醇等挥发性液体也可作为溶剂载体,AFM的应用可为药理学生物大分子互作研究提供一新途径。展开更多
基因调控网络是基于微阵列基因表达数据,对基因之间表达关系依赖程度的一种仿真或重建。从基因表达数据挖掘基因之间存在的一定程度因果关系,对重构基因调控网络具有十分重要的意义。提出一种基于频繁原子序列关联熵的基因关联分析算法...基因调控网络是基于微阵列基因表达数据,对基因之间表达关系依赖程度的一种仿真或重建。从基因表达数据挖掘基因之间存在的一定程度因果关系,对重构基因调控网络具有十分重要的意义。提出一种基于频繁原子序列关联熵的基因关联分析算法,通过基因关联熵有效识别基因之间的因果关系,并采用启发式搜索策略构建基因关联贝叶斯调控网络(gene association based Bayesian regulatory,GABR)。与基因贝叶斯网络描述基因表达水平值之间依赖关系不同,GABR是一种基因序列贝叶斯网络,基因关联分析对象是生物组织样本的基因表达值排序并置换为基因列下标所形成的序列。算法的优势在于基因变量取值原子序列,该基因为原子序列的结果,基因关联熵以及条件概率分布的计算更符合基因表达数据分析的生物本质特征。ALARM网络模拟数据的实验结果表明,基因关联分析算法性能明显优于同类算法。在酵母菌微阵列基因数据GDS2267和小鼠胚胎基因GSE76118等GEO数据集进行实验,测试结果表明GABR方法重构的基因调控网络具有较高的有效性和鲁棒性。展开更多
基金supported by National Natural Science Foundation of China(No.523B2070,No.52225606).
文摘Polymeric perylene diimide(PDI)has been evidenced as a good candidate for photocatalytic water oxidation,yet the origin of the photocatalytic oxygen evolution activity remains unclear and needs further exploration.Herein,with crystal and atomic structures of the self-assembled PDI revealed from the X-ray diffraction pattern,the electronic structure is theoretically illustrated by the first-principles density functional theory calculations,suggesting the suitable band structure and the direct electronic transition for efficient photocatalytic oxygen evolution over PDI.It is confirmed that the carbonyl O atoms on the conjugation structure serve as the active sites for oxygen evolution reaction by the crystal orbital Hamiltonian group analysis.The calculations of reaction free energy changes indicate that the oxygen evolution reaction should follow the reaction pathway of H_(2)O→^(*)OH→^(*)O→^(*)OOH→^(*)O_(2)with an overpotential of 0.81 V.Through an in-depth theoretical computational analysis in the atomic and electronic structures,the origin of photocatalytic oxygen evolution activity for PDI is well illustrated,which would help the rational design and modification of polymeric photocatalysts for efficient oxygen evolution.
文摘目的以课题组纯化获得的蛋白样本为观察对象,对比原子力显微镜(atomic force microscope,AFM)及扫描电子显微镜(scanning electron microscope,SEM)的观察结果,并总结AFM观察生物大分子的主要问题和解决方法。方法将蛋白样本使用PBS稀释至15 nmol·L^(-1),分别固定于载玻片、硅片和云母片上烘干,制成固相观察样本,SEM样本在观察前镀铂,使用AFM及SEM观察蛋白质表面结构,计算样本高度,对比结果差异。结果带正电的蛋白样本在观察时由于AFM探针的斥力会向右偏移;云母片能很好地消除蛋白正电荷从而避免样本移动;PBS能为蛋白样本提供良好的稳定环境,但PBS盐结晶会干扰探针运行和成像清晰度;SEM样本需要镀铂后观察,无法达到AFM的精度。结论使用AFM和SEM均可在体外环境直接观察蛋白质结构,AFM能提供更高精度的观察结果;在蛋白样本稳定性允许的情况下首选超纯水为溶剂载体,乙醇等挥发性液体也可作为溶剂载体,AFM的应用可为药理学生物大分子互作研究提供一新途径。
文摘基因调控网络是基于微阵列基因表达数据,对基因之间表达关系依赖程度的一种仿真或重建。从基因表达数据挖掘基因之间存在的一定程度因果关系,对重构基因调控网络具有十分重要的意义。提出一种基于频繁原子序列关联熵的基因关联分析算法,通过基因关联熵有效识别基因之间的因果关系,并采用启发式搜索策略构建基因关联贝叶斯调控网络(gene association based Bayesian regulatory,GABR)。与基因贝叶斯网络描述基因表达水平值之间依赖关系不同,GABR是一种基因序列贝叶斯网络,基因关联分析对象是生物组织样本的基因表达值排序并置换为基因列下标所形成的序列。算法的优势在于基因变量取值原子序列,该基因为原子序列的结果,基因关联熵以及条件概率分布的计算更符合基因表达数据分析的生物本质特征。ALARM网络模拟数据的实验结果表明,基因关联分析算法性能明显优于同类算法。在酵母菌微阵列基因数据GDS2267和小鼠胚胎基因GSE76118等GEO数据集进行实验,测试结果表明GABR方法重构的基因调控网络具有较高的有效性和鲁棒性。
