THE STRUCTURAL BASIS OF THE POOR FIBRIN SPECIFICITY OF UROKINASE(Ⅰ)——KNOWLEDGE-BASED PREDICTION OF KRINGLE STRUCTURES OF UROKINASE AND ITS RELATED PROTEINS

The Kringle-1 structure of plasminogen (PGK-1), the Kringle-2 structure of tissue plasminogen activator (PAK-2) and the Kringle structure of prourokinase (UKK) has been modeled on the basis of the three-dimensional structure of Kringle-1 of prothrombin (PTK-1) at 2.8 resolution. The predicted three-dimensional structure of these Kringles shows that the binding site of PGK-1 is characterized by an apparent dipolar site, the polar parts of which are separated by a hydrophobic region. PAK-2 possesses the anionic center but has not a cationic binding center which might be provided by a guanidinium group from Arg-69 located adjacent to the Arg-71 position. UKK possesses neither the anionic binding center nor the cationic center which are probably the main reason for the poor fibrin specificity of urokinase.     

手性聚甲基丙烯酸酯液晶聚合物的合成及相行为的研究

手性聚甲基丙烯酸酯液晶聚合物的合成及相行为的研究向前，张纪宇，张树范（中国科学院化学研究所北京１０００８０）关键词手性液晶聚合物，相行为手性侧链液晶聚合物在侧链中含有不对称碳原子的末端基，使聚合物显示Ｓｔ相．Ｓ？相层中的分子呈倾斜排列而产生自发极化．...     

Dynamic Properties of Two-Dimensional Polydisperse Granular Gases

We propose a two-dimensional model of polydisperse granular mixtures with a power-law size distribution in the presence of stochastic driving. A fractal dimension D is introduced as a measurement of the inhomogeneity of the size distribution of particles. We define the global and partial granular temperatures of the multi-component mixture. By direct simulation Monte Carlo, we investigate how the inhomogeneity of the size distribution influences the dynamic properties of the mixture, focusing on the granular temperature, dissipated energy, velocity distribution, spatial clusterization, and collision time. We get the following results: a single granular temperature does not characterize a multi-component mixture and each species attains its own "granular temperature"; The velocity deviation from Gaussian distribution becomes more and more pronounced and the partial density of the assembly is more inhomogeneous with the increasing value of the fractal dimension D; The global granular temperature decreases and average dissipated energy per particle increases as the value of D augments.     

液相色谱-四极杆/静电场轨道阱高分辨质谱鉴定一种新精神活性物质5F-MDMB-PICA在斑马鱼体内的代谢产物

通过建立斑马鱼模型研究5F-MDMB-PICA(3,3-二甲基-2-[1-(5-氟戊基)吲哚-3-甲酰氨基]丁酸甲酯)的体内代谢转化途径,利用液相色谱-四极杆/静电场轨道阱质谱(LC-Q-Orbitrap MS)技术,结合Mass Frontier软件对5F-MDMB-PICA及其代谢产物进行质谱解析和结构分析.结果表...     

Interfacial Charge Transfer Induced Electronic Property Tuning of MoS_2 by Molecular Functionalization

The modulation of electrical properties of MoS_2 has attracted extensive research interest because of its potential applications in electronic and optoelectronic devices.Herein,interfacial charge transfer induced electronic property tuning of MoS_2 are investigated by in situ ultraviolet photoelectron spectroscopy and x-ray photoelectron spectroscopy measurements.A downward band-bending of MoS_2-related electronic states along with the decreasing work function,which are induced by the electron transfer from Cs overlayers to MoS_2,is observed after the functionalization of MoS_2 with Cs,leading to n-type doping.Meanwhile,when MoS_2 is modified with 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane(F_4-TCNQ),an upward band-bending of MoS_2-related electronic states along with the increasing work function is observed at the interfaces.This is attributed to the electron depletion within MoS_2 due to the strong electron withdrawing property of F_4-TCNQ,indicating p-type doping of MoS_2.Our findings reveal that surface transfer doping is an effective approach for electronic property tuning of MoS_2 and paves the way to optimize its performance in electronic and optoelectronic devices.     

物理科学发展史的回顾与聚集力学的创建

本文简单地阐述了物理科学的发展电,在19世纪末期,物珲科学已经有相当发展,并形成了三个科学分支--研究物体运动,有牛顿力学;研究物质热运动,有热力学和统计力学;研究电磁波和光波,有电动力学,可是,这三种经典力学在20世纪初面临着新的挑战(困难),从而,相应地产生了三种新的基础理论,即狭义相对论,广义相对论;聚集理论,聚集力学;量子理论,量子力学,具体实践表明,它们在解决新的难题方面都取得很大成功.     

Py-GC/MS分析技术与其在烟用中草药添加剂中的应用

通过热裂解实验,可以更加深入地了解卷烟燃吸过程中各个燃烧条件和整个烟气化学的关系,还可对不同温度下的裂解产物和作用机理进行研究。本文综述了裂解-气相色谱/质谱法在烟用中草药添加剂研究中的应用。     

用于长城等古建筑探测的NMR探测器的磁体设计

以万里长城为代表的古建筑是世界瑰宝,更是中华民族的象征和骄傲.本文提出利用便携式核磁共振（NMR）装置来探测研究这类古建筑的建筑材料,在不对其造成损伤的基础上,发掘其隐含的科学、技术和工程相关的丰富信息.为此,作为第一步,设计了适合于探测这类古建筑的便携式单边NMR探测器组合式磁体.该探测器的磁体结构以semi-Halbach为基础,通过不同磁体模块间的组合得到对应移动探测模式、长距离探测模式和均匀磁场探测模式的磁体结构.随后根据优化结果,设计加工了磁体组件,并采用该磁体进行了流体、长城城砖和现代红砖的NMR实验,实测结果与模拟一致.该组合式磁体的优点在于通过不同磁体模块组合,实现了多种探测方式,适用于探测长城等这类古建筑物需要多种探测模式的科学研究.     

基于冠层尺度的枣树色素含量的高光谱估算模型

植物冠层色素含量与氮素含量具有高度的相关性,是农业遥感中的关键研究因素。本研究的主要目的是：(1)对比偏最小二乘回归和支持向量机两种建模方法对枣树冠层色素的预测精度;(2)构建基于高光谱数据的枣树冠层色素含量定量反演模型,为枣树冠层色素含量的快速、无损、廉价、环保的测定提供一定的理论依据和技术支持。相关性分析结果表明,枣树冠层色素与高光谱数据之间具有较好的相关性,但叶绿素、叶绿素a要优于叶绿素b和类胡萝卜素。独立样本对模型的预测性能检验结果表明,偏最小二乘回归和支持向量机均能有效的估算枣树色素含量,但不同色素的偏最小二乘回归模型和支持向量机模型的预测精度存在一定的差异,叶绿素和类胡萝卜素的支持向量机模型的预测精度要高于偏最小二乘回归模型,而叶绿素a和叶绿素b则相反。比较不同色素的最佳反演模型的预测精度表明,叶绿素、叶绿素a和类胡萝卜素的预测精度要优于叶绿素b,前三者的决定系数大于0.8,残余预测误差高于2.0,平均相对误差低于13%,而叶绿素b的对应值分别为0.60%,20.79%和1.79%。     

Au@ZrO2空心纳米微球的制备及其催化性质

以Stober法合成了不同粒径的SiO₂微球。以这些SiO₂微球为硬模板,通过ZrOCl₂前驱体吸附和水解制备得到了ZrO₂@SiO₂复合物,然后用HF溶解去除二氧化硅模板剂,制备得到ZrO₂空心球。以ZrO₂空心球为载体,采用沉积-沉淀法（DP）合成了Au@ZrO₂纳米空心微球。考察了Au@ZrO₂纳米空心微球在对硝基苯胺还原反应中的催化性能。研究结果表明,所合成的SiO₂微球粒径大小均一、形状规则、分散性好;ZrO₂空心微球大小及比表面积可以通过硬模板SiO₂微球粒径进行有效控制;与Au@ZrO₂实心微球相比,Au@ZrO₂空心微球在对硝基苯胺还原反应中表现出良好的催化性能,当反应温度为45℃、反应7 min时,对硝基苯胺能够完全转化为对苯二胺。