Analytical approach in diagnosis of inherited metabolic diseases: Maple syrup urine disease (MSUD) – simultaneous analysis of metabolites in urine by enantioselective multidimensional capillary gas chromatography-mass spectrometry (enantio-MDGC-MS)

Maple Syrup Urine disease (USUD) is an autosomal recessive inherited metabolic disorder of branched-chain amino acid (L-valin, L-leucine, and L-isoleucine metabolism named after the characteristic smell of affected patients urine. MSUD is caused by a deficiency of the branched-chain α-keto acid dehydrogenase compex resulting in an accumulation of branched-chain aamino acids and the corresponding α-keto-and α-hydroxy acids in blood, urine and cerebrospinal fluid causing neurological damage and mental retardation. The enantioselective analysis of chiral MSUD metabolites and analysis of achiral compounds as corresponding N,O-methoxycarbonyl methyl esters by derivatization with methyl chloroformate (MCF) has been achieved simultaneusly by enantioselective multidimensional gas chromatography-mass spectrometry using heptakis (2,3-di-O-methyl-6-O-tert-butyl-dimethyl-silyl)-β-cyclodextrin as chiral stationary phase. Derivatization with MCF allows the analysis of the structurally different metabolitetes such as branched-chain-carboxylic-, α-oxo-, α-hydroxy- and α-amino acids in a single chromaatographic run. Mass selective detection immensely improves the unequivocaaal identification of metabolites even when they occur as trace compound. The described method allows a reliable screening of MSUD metabolites in patients' urine without time consuming sample preparation and is also suitable for label enrichment analysis without any methodical changes. During this investigation urine sample from three MSUD paatients were analyzed.     

基于Maple软件辅助绘制自由基二元共聚曲线的研究

运用数据处理软件(maple)对经典的自由基二元聚合公式进行图形绘制,得到了二元单体之间共聚关系的三组图.一是二元单体的自由基共聚曲线图F1-f1,二是聚合物中单体平均组成(Fp)与投料单体浓度(f1)的关系曲线图,三是聚合物转化率(C)与投料单体(f1)的关系曲线图.通过二组具有代表性的共聚实例,分别是有恒比点的非理...     

New exact solutions of the Broer–Kaup equations in (2 + 1)-dimensional spaces

With the aid of Maple, several new kinds of exact solutions for the Broer–Kaup equations in (2 + 1)-dimensional spaces are obtained by using a new ansätz. This approach can also be applied to other nonlinear evolution equations.     

用Maple计算机代数系统实行电动力学教学改革的一尝试

介绍了Ｍａｐｌｅ计算机代数系统的特点及应用该系统实行电动力学教材和教学方法改革的初步尝试。     

Calculus of one and more variables with Maple

This is a guide to using Maple in teaching fundamental calculus of one, two and three variables (limits, derivatives, integrals, etc.), also suitable for Maple beginners. It outlines one of the ways to effective use of computers in the teaching process. It scans advantages and disadvantages of using Maple in relation to students and teacher. The guide includes hints for creating teaching materials. This article is supported by the author's 10-year experience of teaching calculus with Maple.     

A New Algorithm for the Petrov Classification of the Weyl Tensor

A new algorithm for the Petrov classification of the Weyl tensor is introduced. It is similar to the Letniowski-McLenaghan algorithm [1] when some of the 's are zero, but offers a completely new approach when all of the 's are nonzero. In all cases, new code in Maple has been implemented.     

细长柔韧压杆弹性失稳后挠曲线形状的计算机仿真

采用Maple编程对细长柔韧压杆弹性失稳后挠曲线形状进行了计算机仿真,进行了细长柔韧压杆弹性失稳后最大挠度和挠曲线封闭两种情况下的挠曲线形状仿真和详细的解答.分析计算了失稳后屈曲的力学特征,给出了解析表达式;分析计算了失稳后屈曲的平衡状态曲线的几何特征,绘出了计算机仿真曲线.结果表明:失稳后最大挠度和挠曲线封闭是属于两个完全不同的屈曲状态.     

应用Maple软件分析带电粒子在匀强正交电磁场中的运动

结合数学软件Maple,通过求解微分方程分析带电粒子在匀强正交电磁场中的运动规律．     

一维热传导方程的maple模拟

热传导方程是一种偏微分方程。对于有界热传导齐次方程的混合问题,用分离变量法求解往往很复杂,也很抽象。为了更好的理解方程的解,更直观的看出它的物理意义,本文用Maple软件将方程的解用图像表示出来。先用pdsolve函数求解方程,再用PlotSd函数进行绘图,通过改变边界条件,比较了图形的变化情况。从结果可以看出Manle软件对于热传导方程求解和绘图十分简便,也很直观。在物理教学中可以得到很好的应用。     

A modified extended method to find a series of exact solutions for a system of complex coupled KdV equations

In this paper an algebraic method is devised to uniformly construct a series of complete new exact solutions for general nonlinear equations. For illustration, we apply the modified proposed method to revisit a complex coupled KdV system and successfully construct a series of new exact solutions including the soliton solutions and elliptic doubly periodic solutions.