基于双分子信标对猪圆环病毒Ⅱ型的简单快速检测

根据猪圆环病毒(PCV2)基因组为单链DNA的特点,设计了两条可与PCV2基因组序列特异性杂交的分子信标,建立了基于双分子信标法检测PCV2的方法。实验结果表明,双分子信标法比单分子信标法的灵敏度更高。在10 mmol/L MgCl2、20 mmol/L Tris-HCl(pH=8.0)的杂交缓冲溶液,40℃孵育30 min的优化检测体系下,此方法可实现对检测样本在2~200 nmol/L线性范围内的检测,检出限可达1 nmol/L。将双分子信标检测体系用于18例可疑猪瘟样品病毒检测,其中8例呈PCV2阳性,检测结果与PCR法一致,证明此双分子信标法可用于实际猪感染PCV2的诊断。     

Proteomic analysis of chondrocytes exposed to pressure

Chondrocytes are the only cell type present in mature articular cartilage (2-5% of total tissue). The biological activities of the chondrocyte population are regulated by genetic, biologic and biochemical factors, as well as environmental factors (stress, flow and electric field). Although compressive forces within joint articular cartilage are required for maintenance of the normal composition of articular cartilage, there is a lack of knowledge about the number of pressure-related proteins expressed in articular cartilage. Two-dimensional gel electrophoresis (2-DE) and high-performance liquid chromatography-electrospray/tandem mass spectrometry (HPLC/ESI-MS/MS) were used to identify the levels of pressure-related proteins expressed by chondrocytes grown in the presence or absence of hydrostatic pressure. A total of 266 spots were excised from the gels and analyzed by HPLC/ESI-MS/MS. Functional classification of up-regulated proteins indicated that energy and protein fate were the main biological processes occurring in pressurized chondrocytes. Furthermore, membrane-bound transferrin-like protein p97, a marker of chondrocyte differentiation, was only expressed in chondrocytes under hydrostatic pressure. These data suggest that hydrostatic pressure can induce cell differentiation by increasing the expression level of energy metabolism- and protein fate-related proteins, indicating that hydrostatic pressure may be needed for normal biosynthesis and differentiation of articular chondrocytes.     

Bridging the gap between mathematical conjecture and proof through computer-supported cognitive conflicts

In many mathematical problems, students can feel that the universalityof a conjecture or a formula is validated by their experimentand experience. In contrast, students generally do not feelthat deductive explanations strengthen their conviction thata conjecture or a formula is true. In order to cope up withstudents’ conviction based only on empirical experienceand to create a need for deductive explanations, we developeda problem-solving activity with technology support intendedto cause cognitive conflict. In this article, we describe theprocess conducted for this activity that led students to contradictionsbetween conjectures and findings. The teacher could create familiarproblem-solving situations and use students’ naïveinductive approaches to make students think mathematically andestablish the necessity for proof via computer support.     

Existence of Formal Conservation Laws of a Variable-Coefficient Korteweg--de Vries Equation from Fluid Dynamics and Plasma Physics via Symbolic Computation

Employing the method which can be used to demonstrate the infinite conservation laws for the standard Kortewegde Vries （KdV） equation, we prove that the variable-coeFficient KdV equation under the Painlevé test condition also possesses the formal conservation laws.     

温敏核不育系水稻株1S及其矮秆突变SV14茎的蛋白质组学比较

采用双向凝胶电泳对温敏核不育水稻株1S和其矮秆突变体SV14的茎(穗颈下第1节和第2节)蛋白进行了分离,通过银染显色,获得了分辨率和重复性较好的双向电泳图谱.选取了26个蛋白质点采用MALDI-TOF-MS进行肽质谱指纹图分析,最终有12个蛋白质点得到了可靠鉴定.其中在SV14中相对于株1S上调的仅有OSJNBa0039C07.13 蛋白,其它蛋白均表现为下调.这些差异蛋白按照功能可分为4类: (1) 能量代谢相关蛋白;(2) 次生代谢相关蛋白;(3) 调控蛋白;(4) 未知蛋白.对光合系统Ⅱ氧延伸复合物蛋白质前体2,果糖二磷酸醛缩酶,UDP-葡糖醛酸脱羧酶对应的基因进行了半定量RT-PCR分析,发现这几个基因与蛋白质的表达不一致,可能是RNA发生了翻译后修饰而减少了蛋白表达量的结果.这些差异蛋白很可能与水稻矮化有关,为水稻矮秆基因的寻找提供了另一个有效途径.     

FCC催化剂氢气还原活化脱镍研究

我国的FCC催化剂在使用中镍污染较为严重, 镍不仅会破坏催化剂的结构, 而且还会影响反应产物的分布, 增加企业的生产成本. 本研究提出了氢气还原活化＋稀硝酸洗涤的脱镍新方法, 具有良好的效果. 镍在FCC催化剂上以NiAl₂O₄和Ni₂SiO₄的形式存在, 这些物种在700 ℃以下就可以被氢气还原, 并且随着温度的升高, 不仅催化剂表面的镍能够被还原, 而且催化剂体相中的镍也可以迁移到表面从而被还原, 但这种迁移受到平衡的限制. 还原后生成的金属镍可以溶于稀硝酸, 因而可以洗涤除去. 在适宜的条件下, 经过一次还原＋酸洗处理, 脱镍率可达到50%以上; 经过两次处理, 脱镍率可达75%以上. 脱镍后催化剂的微反活性可以得到大幅度提高.     

预先负载原料法合成ZSM-5/SAPO-5复合分子筛

采用预先负载原料法合成了一系列ZSM-5/SAPO-5(核/壳)双结构分子筛, 研究了预负载磷酸的条件对核壳结构分子筛的形成及性质的影响, 采用X射线衍射、扫描电子显微镜、X射线能量散射谱和红外光谱等手段对样品进行了表征. 结果表明, 负载原料的预处理条件明显影响磷与ZSM-5间的作用力及复合分子筛的结晶度和颗粒形貌等特性. 与常规合成方法相比, 在适宜的条件下采用这种方法更有利于小颗粒SAPO-5分子筛的形成及其在ZSM-5表面的生长.     

NO在清洁和Cs覆盖的Ru(100)表面上吸附的热脱附谱

用热脱附谱等方法研究了NO分别在清洁和Cs覆盖的Ru(1010)表面上的吸附.结果表明:存在两种NO分子吸附态(a1,a2),脱附温度分别处于325℃和550℃附近.Cs的存在增加了Ru(1010)表面上a2态的吸附位置,提高了该态的脱附温度.Cs在Ru(1010)表面上的存在同时促进了吸附NO分子的分解.NO在Ru(1010)表面上分解后形成吸附O原子和N原子.N原子复合以N2在约500℃附近脱附,同时Cs的存在也促进了N2O的形成.在Cs覆盖的Ru(1010)表面上,N2O的脱附温度约在425℃.     

BPM Simulation and Comparison of 1 × 2 Directional Waveguide Coupling and Y-Junction Coupling Silicon-on-Insulator Optical Couplers

For developing large area opto-electronic silicon-on-insulator (SOI) devices, the optical coupler is a basic key device. In this article, the authors design and simulate 1 2 2 directional waveguide coupling and Y-branch coupling optical couplers based on Unibond SOI rib waveguides. The beam propagation method (BPM) is used for light propagation analysis. The simulation results and comparisons of the two kinds of optical couplers are reported. The S-bend waveguide for attaching to the two kinds of SOI optical coupler is also analyzed by BPM. We find that the directional coupler has lower power loss, but the Y-junction coupler is more wavelength insensitive with the same device size and splitting angle. The fabrication tolerance analysis shows Y-junction coupler has better fabrication characteristics.