Comparison of Different Cartridges of Solid Phase Extraction for Determination of Polyphenols in Tobacco by UPLC/MS/MS and Multivariate Analysis

The comparison of solid phase extraction(SPE) for the preconcentration and isolation of polyphenols in tobacco samples was carried out by ultra-high performance liquid chromatography/tandem mass spectrometry (UPLC/MS/MS) and multivariate analysis.Several adsorbing materials of SPE(C18,NH2,SAX and OASIS) were investigated.It was found that the C18 and OASIS cartridges can not only speed up the purification process,but also simplify the SPE operation.A UPLC/MS/MS was used for the determination of polyphenols ...     

Metabolic Profiling of Human Colorectal Cancer Using High Resolution 1H Nuclear Magnetic Resonance Spectroscopy

Colorectal cancer (CRC) is the third commonest malignancy cancer worldwide. Clear understandings of global metabolic profiling of the normal mucosa and cancer tissues are vitally important to aid optimizing the clinical management strategy and understanding CRC biology. We studied metabolic characteristics of 20 CRC and 20 distant normal mucosa tissues extracts from 20 patients using high resolution ¹H NMR spectroscopy in conjunction with multivariate analyses, such as principal component analysis (PCA). Compared with distant normal mucosa tissues, lactate, taurine, ornithine and polyamine were present at significantly higher levels in CRC tissue extracts whereas myo‐inositol was present at significantly lower level. Two metabolites ratios such as myo‐inositol/taurine and myo‐inositol/(ornithine+polyamine) appear to be the most valuable biomarkers for the differentiation CRC from normal mucosa tissues. Our data suggested that HR ¹H NMR spectroscopy combined with multivariate analyses is a potentially useful technology for detecting malignant changes in the normal mucosa tissues, the technique may be further exploited for future CRC biomarker research or identification of targets for therapeutic manipulations.     

Cisplatin-induced alteration on membrane composition of A549 cells revealed by ToF-SIMS

Cisplatin has been clinically used for treatment of solid tumors such as non–small-cell lung cancer for decades. However, tumor resistance may be acquired with losing the antitumor activity of cisplatin. As cellular membrane is the first barrier that cisplatin has to overcome before its further action inside the cells, the membrane composition must play a vital role in the cisplatin uptake and excretion, which further influences cisplatin sensitivity. In this work, we applied time-of-flight secondary ion mass spectrometry (ToF-SIMS) surface analysis combined with principle component analysis to distinguish the differences of cell membrane composition between non–small-cell lung cancer cells (A549) and its cisplatin resistant counterpart A549/DDP cells. The decreased phosphatidylcholine content and more abundant cholesterol were observed in the drug resistant cell surfaces, indicating the decreased membrane fluidity of A549/DDP cells. Moreover, we further compared membrane composition of A549 and A549/DDP cells after being treated with different concentrations of cisplatin. A higher composition level of proteins was discovered on all groups of A549/DDP cell membranes. The altered surface chemistry of cellular membranes induced by cisplatin indicates the significance of membrane structures in the drug resistance, which deserves further investigations to this regard.     

高效液相色谱-四极杆/飞行时间质谱鉴定阿莫西林克拉维酸钾干混悬剂中的未知组分

采用高效液相色谱-四极杆/飞行时间质谱(HPLC-QTOF/MS)建立了阿莫西林克拉维酸钾混悬剂(ACPS)中未知组分的鉴定方法,以BDS Hypersil C18(4.6 mm×250 mm,5μm)为色谱柱,以乙腈-水(0.1%甲酸)为流动相,流速为1 mL/min。比较了中国药典方法和HPLC-QTOF/MS方法的相关性;利用半制备液相色谱收集未知组分,并在HPLC-QTOF/MS体系中进行定位和确认,确定未知组分在液质体系中的出峰位置和准确分子量;筛查混合空白辅料成分,并通过与标准品比对,利用HPLC-QTOF/MS鉴定ACPS的未知组分为糖精钠。方法可为抗生素药品中未知组分的鉴定提供参考。     

Quality by Design Approach for Development of W/O Type Microemulsion-Based Transdermal Systems for Atenolol

The objective of the present investigation was to develop microemulsion-based transdermal systems of highly water soluble drug, Atenolol, by quality by design technique. Atenolol-loaded W/O microemulsions were optimized using D-optimal design with concentrations of oil, surfactants mixture, and water as independent variables, which was converted into microemulsion-based gel (MBG). The results of in vitro permeation of the optimized batch of Atenolol-loaded MBG revealed significant increase in permeability parameters as compared to its convention gel. All results suggested suitability of W/O type MEs as carriers for transdermal delivery of highly water soluble drug, Atenolol.     

Synthesis of Novel α‐(Acyloxy)‐α‐(quinolin‐4‐yl)acetamides by a Three‐Component Reaction between an Isocyanide,Quinoline‐4‐carbaldehyde,and Arenecarboxylic Acids

Novel α‐(acyloxy)‐α‐(quinolin‐4‐yl)acetamides were synthesized by the Passerini three‐component reaction between an isocyanide, quinoline‐4‐carbaldehyde, and arenecarboxylic acids in H₂O. The reactions were carried out in one pot at room temperature with quantitative yields.     

PBL节点初始平动刚度计算及设计参数优化

为研究钢桁腹混凝土组合箱梁中PBL(Perfobond Leiste)节点的初始平动刚度及其影响因素,首先基于组件法,运用卡氏第二定理推导出考虑了开孔钢板与混凝土间的界面剪切力和混凝土榫贡献的PBL节点的初始平动刚度表达式,其次以某工程实例为背景,结合有限元模型验证所推公式的合理性;在此基础上分析了混凝土强度、腹杆直径、腹杆壁厚、开孔钢板开孔孔径和开孔钢板厚度等构造参数对初始平动刚度的影响,并利用正交分析法对以上5个参数进行优化组合。研究结果表明,本文方法计算的PBL节点初始平动刚度结果与有限元计算结果间的误差在8.0%以内;相较运用解三角形计算腹杆平动位移的方法,采用卡氏第二定理不仅可以简化计算,还可以减小解三角形过程中因多次计算变形带来的误差累积;腹杆刚度对PBL节点整体平动刚度的贡献最大,可达到82.5%;保持原设中的混凝土强度不变,将腹杆直径增加20 mm,将钢腹杆壁厚增加4 mm,将开孔钢板开孔孔径增加4 mm,将开孔钢板厚度增加4 mm,可以将PBL节点理论初始平动刚度提高约25.7%。     

基于独立成分分析的高光谱图像异常检测

针对高光谱图像中背景及目标先验知识未知条件下的异常目标检测问题,提出了一种基于独立成分分析(ICA)的异常探测算法.首先估计原始数据的虚拟维(VD)以确定要分离的独立成分个数,在此基础上进行快速独立成分分析(FastICA),然后基于平均局部奇异度选择含异常信息较多的独立成分,最后使用丰度量化算法得到异常目标的丰度图像...     

弱脉冲光时域平衡零拍测量的实验研究

设计了一套可以用来测量弱脉冲光时域噪声信息的平衡零拍探测系统,通过对本底光散粒噪声基准的测量分析了该系统的各项性能指标,并且对弱相干光脉冲进行了正交位相振幅分量的噪声测量。     

对主成分分析法三个问题的剖析

从主成分分析法的基本原理入手,针对教学过程中学生对主成分分析法感到费解的三个问题进行了逐一剖析:1.为什么主成分系数是经标准差标准化后原始变量的协方差矩阵的特征向量?2.特征向量正负号如何选取?对进一步的研究如计算综合得分和聚类分析有何影响?3.主成分载荷值是如何得来的?同时指出有些教材在计算主成分得分时混淆了主成分载荷和特征向量的概念,以致造成错误的结果.