Identification and quality evaluation of different processed products of Aconitum carmichaelii by ultra-high-performance liquid chromatography-quadrupole time-of-flight tandem mass spectrometry and ultra-high-performance liquid chromatography-tandem mass spectrometry

Aconitum carmichaelii is widely used to treat chronic and intractable diseases due to its remarkable curative effect, but it is also a highly toxic herb with severe cardiac and neurotoxicity. It has been combined with honey for thousands of years to reduce toxicity and enhance efficacy, but there has been no study on the chemical constituent changes in the honey-processing so far. In this study, the chemical constituents of A. carmichaelii before and after honey-processing were characterized by ultra-high-performance liquid chromatography-quadrupole time-of-flight tandem mass spectrometry. The results showed that a total of 118 compounds were identified, of which six compounds disappeared and five compounds were newly produced after honey-processing, and the cleavage pathway of main components was elucidated. At the same time, 25 compounds were found to have significant effects on different products, among which four compounds with the biggest difference were selected for quantitative analysis by ultra-high-performance liquid chromatography-tandem mass spectrometry. This study not only explained the chemical differences between the different products, but also helped to control the quality of the honey-processed products more effectively, and laid a foundation for further elucidating the mechanism of chemical constituent change during the honey-processing of A. carmichaelii.     

Survival of Branching Random Walks in Random Environment

We study survival of nearest-neighbor branching random walks in random environment (BRWRE) on ℤ. A priori there are three different regimes of survival: global survival, local survival, and strong local survival. We show that local and strong local survival regimes coincide for BRWRE and that they can be characterized with the spectral radius of the first moment matrix of the process. These results are generalizations of the classification of BRWRE in recurrent and transient regimes. Our main result is a characterization of global survival that is given in terms of Lyapunov exponents of an infinite product of i.i.d. 2×2 random matrices.     

Long-time behavior of solutions for quasilinear hyperbolic hemivariational inequalities with application to piezoelectricity problem

We consider quasilinear autonomous inclusions of hyperbolic type. The dynamics of all weak solutions defined on the positive semi-axis of time is studied. We prove the existence of trajectory and global attractors and investigate their structure. The classes of mathematical models for piezoelectric fields containing the multidimensional law are studied. The conditions of the output of each weak solution for this problem at stationary states are given. We consider as a particular case the piezoelectric model for PZT-4 piezoceramics as one of the possible applications.     

Expected Reflection Distance in G(r, 1, n) after a Fixed Number of Reflections

Extending to r > 1 a formula of the authors, we compute the expected reflection distance of a product of t random reflections in the complex reflection group G(r, 1, n). The result relies on an explicit decomposition of the reflection distance function into irreducible G(r, 1, n)-characters and on the eigenvalues of certain adjacency matrices.Received December 8, 2003     

Measuring pre-service teachers’ self-efficacy in tutoring children in primary mathematics: an instrument

This article reports on the use of Rasch modelling to develop and validate an instrument measuring self-efficacy in tutoring children in primary mathematics (SETcPM). In response to the literature on teacher efficacy, the 20-item instrument aims to inform teacher educators, and is designed for novice pre-service teachers (nPSTs) preparing to teach mathematics in primary school (grades 1–7, ages 6–13). To ensure that the tasks of teaching are imaginable for nPSTs, the instrument targets the core activity of teaching mathematics: helping a generic child with mathematics tasks. We propose that SETcPM is measurable for the intended population and represents a central part of self-efficacy in teaching mathematics (SETM). Understanding the initial SETcPM of novices and mapping its development over the course of their training programme can contribute to a better understanding of SETM, and allow teacher educators to tailor their support.     

Optimal Point Placement for Mesh Smoothing

We study the problem of moving a vertex in an unstructured mesh of triangular, quadrilateral, or tetrahedral elements to optimize the shapes of adjacent elements. We show that many such problems can be solved in linear time using generalized linear programming. We also give efficient algorithms for some mesh smooth ing problems that do not fit into the generalized linear programming paradigm.     

利用共振镜生物传感器研究牛胰脱氧核糖核酸酶Ⅰ与DNA的相互作用

利用IAsys共振镜生物传感器研究了牛胰脱氧核糖核酸酶Ⅰ(Bp DNase Ⅰ)与DNA的相互作用.求出了不同温度下,Bp DNase Ⅰ与DNA相互作用的结合和解离的动力学速率常数(Kass,Kdiss)和平衡常数(KA,KD),并且计算出了该过程的热力学参数(ΔH和TΔS).在298 K时该结合过程的KA=(3.521 2±0.232 4)×105(mol/L)-1,KD=(2. 852 4±0. 188 3)×10-6 mol/L,TΔS 为(84. 860±3. 712) kJ/mol,该结合过程的ΔH 为(53.222±3.548) kJ/mol,是一个熵驱动的过程.本文还对Mg2 浓度对Bp DNase Ⅰ与DNA的相互作用的影响进行了研究.在相同温度下,Bp DNase Ⅰ与DNA的结合作用在有Mg2 存在时较无Mg2 存在时高约30.5 倍,表明Mg2 能极大地提高Bp DNase Ⅰ与DNA的结合能力.     

Global Solutions of an Obstacle-Problem-Like Equation with Two Phases

Concerning the obstacle-problem-like equation , where ₊ > 0 and _– > 0, we give a complete characterization of all global two-phase solutions with quadratic growth both at 0 and infinity.