High throughput identification of components from traditional Chinese medicine herbs by utilizing graphene or graphene oxide as MALDI-TOF-MS matrix

In this work, graphene or graphene oxide was utilized, for the first time, to identify small molecular components from traditional Chinese medicine (TCM) herbs, by acting as matrix of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS). Due to the large surface area of graphene or graphene oxide, the analytes were trapped tightly to the matrix, which avoids the contamination of the ion source and vacuum system. Besides, their excellent electronic, thermal and mechanical properties make them desired matrices for MALDI-TOF-MS. Stable analysis was achieved with no background inference even at the concentration of 100 nM. Moreover, the limit of detection (LOD) could be greatly lowered by utilizing graphene or graphene oxide as a pre-enrichment adsorbent. In summary, the promoted MALDI-TOF-MS methodology was demonstrated to be simple, sensitive, fast, cost effective and, most importantly, high throughput.     

Determination of oleanolic and ursolic acid in Chinese herbs using HPLC and γ-CD as mobile phase modifier

To separate and determine oleanolic acid and ursolic acid, a rapid and accurate HPLC using γ‐CD as the mobile phase additive was developed. The effect of CD nature and concentration, and the acidity of the mobile phase on the chromatographic behavior of two bioactive triterpenes were systematically studied. Two bioactive triterpenes were completely separated (R = 3.11) on a Kromasil^® C₁₈ column (150×4.6 mm id, 5 μm) with the mobile phase consisting of acetonitrile/0.1% phosphoric acid with 2 mM γ‐CD as the mobile phase modifier (60:40, v/v). The flow rate was set at 1.0 mL/min and the eluent was detected at 210 nm for two bioactive triterpenes. The linearity of the method was excellent (r=0.9999) over the studied range of 6–300 μg/mL for oleanolic acid, and 12–600 μg/mL for ursolic acid. The LOD and LOQ were 1.5 and 5.0, 1.0 and 3.0 μg/mL for oleanolic acid and ursolic acid, respectively. The optimized method was successfully applied to separate and determine two bioactive triterpenes in five Chinese herbs. It is concluded that this method could be used for rapid and accurate qualitative and quantitative analysis of the two bioactive triterpenes in Chinese herbs.     

Liquid‐Chromatography Quantitative Analysis of 20 Amino Acids after Derivatization with FMOC‐Cl and Its Application to Different Origin Radix isatidis

We developed a simple, rapid and reliable method for determination of 20 common amino acids based on derivatization with 9‐fluorenylmethyl chloroformate (FMOC‐Cl) and RP‐LC/UV, this method was first introduced into quantitative analysis of amino acids. The amino groups of amino acids were trapped with FMOC‐Cl to form amino acid‐FMOC‐Cl adducts which can be suitable for LC‐UV. Chromatographic separation was performed on a C₁₈ column with a mobile phase gradient consisting of acetonitrile and sodium acetate solution. This method was shown to be sensitive for 20 common amino acids. In the intra‐day precisions assay, the range of RSDs was 3.21‐7.67% with accuracies of 92.34‐102.51%; for the inter‐day precisions assay, the range of RSDs was 5.82‐9.19% with accuracies of 90.25‐100.63%. The results also indicated that solutions of amino acids‐FMOC‐Cl can be kept at room temperature for at least 24 h without showing significant losses in the quantified values. The validated method was successfully applied to the determination of major four kinds of amino acids in R. isatidis samples (Arg, Pro, Met and Val). The total content of amino acids in different origin R. isatidis was 13.32‐19.16 mg/g. The differences between R. isatidis samples were large using HCA.     

书法艺术的计算机模拟及其实现

利用现代的计算机技术，可以使书法这门古老而又璀灿的艺术明珠增添新的魅力。本文详细介绍了计算机模拟毛笔书法的思想及具体实现方法。     

Routing problems: A bibliography

This bibliography contains 500 references on four classical routing problems: the Traveling Salesman Problem, the Vehicle Routing Problem, the Chinese Postman Problem, and the Rural Postman Problem. References are presented alphabetically under a number of subheadings.     

On unique range sets for meromorphic or entire functions

This paper has studied the Gross uniqueness question ignoring multiplicity and relating multiple values, and extended and improved on some related results in [1–8]. Supported in part by National Natural Science Foundation of China     

四种补肾中成药微量元素含量的研究

从微量元素含量的角度,采用电感耦合等离子体发射光谱法,对四种常用补肾中成药中微量元素的含量进行了初步研究.研究结果表明,补肾阳药中钙、磷、镁、铁、钾含量普遍高于补肾阴药,与中医辨证施治的理论相一致.     

中国古代历法推没灭术算理分析

指出由于唐朝科学家张遂对灭给出了新的定义，从而，以《大衍历》为界，可将我国古代历法中的推没，灭术分为两个阶段；分析了这两个不同阶段里没，灭算法的数学原理；对没，灭在古历中的作用提出了初步的看法。     

荧光光谱法对中药注射液热稳定性的研究

采用荧光光谱法对中药注射液热稳定性进行了初步探讨。发现在恒温（40℃、80℃）条件下、不同中药注射液随时间变化的荧光强度和荧光谱图，呈现出类似规律性的变化，但又有各自的特点。通过对其谱图和荧光强度的分析，能够反映出中药注射液在受热条件下，随时间变化的荧光谱的差异，不同温度对谱峰强度的差异性影响及不同注射剂热稳定性变化曲线的差异，从而提示中药注射液受热变质中组分变化的一些特点。找出了不同温度下不同中药注射液荧光强度减弱10％的时间。     

Covering partially directed graphs with directed paths

We consider graphs which contain both directed and undirected edges (partially directed graphs). We show that the problem of covering the edges of such graphs with a minimum number of edge-disjoint directed paths respecting the orientations of the directed edges is polynomially solvable. We exhibit a good characterization for this problem in the form of a min-max theorem. We introduce a more general problem including weights on possible orientations of the undirected edges. We show that this more general weighted formulation is equivalent to the weighted bipartite b-factor problem. This implies the existence of a strongly polynomial algorithm for this weighted generalization of Euler's problem to partially directed graphs (compare this with the negative results for the mixed Chinese postman problem). We also provide a compact linear programming formulation for the weighted generalization that we propose.