湘黄精中高异黄酮类化学成分研究

目的 对黄精属植物湘黄精Polygonatum hunanense H. H. Liu&B. Z. Wang的干燥根茎进行化学成分研究。方法 综合运用硅胶、Sephadex LH-20凝胶、半制备HPLC等方法对湘黄精乙酸乙酯部位进行分离纯化,根据波谱数据、理化性质等技术手段对化合物结构进行鉴定。结果 最终从湘黄精根茎95%乙醇提取物中分离得到13个化合物,分别鉴定为5,7-dihydroxy-6-methyl-3-(4-methoxybenzyl)-chroman-4-one (1)、5,7-dihydroxy-3-(2-hydroxy-4-methoxybenzyl)-chroman-4-one (2)、ophiopogonanone G (3)、3-(4′-hydroxy-benzyl)-5,7-dihydroxy-6-methyl-chroman-4-one (4)、(±)-5,7-dihydroxy-6,8-dimethyl-3-(2′-hydroxy-4′-methoxybenzyl-)chroman-4-one (5)、3-(2′,4′-dihydroxybenz...     

论物证理化检验中的种属认定和同一认定

传统的观点认为物证理化检验只能进行种属认定。物证理化检验中的种属认定和同一认定仅仅是依据了不同层次的物证反映体所导致的来源(或个体)同一认定范围上的区别。随着科学技术的发展和人类认识世界能力的不断加强,物证理化检验一定可以实现从种属认定向同一认定的转化。必须坚持物证检验与案件性质和侦查过程相结合的方法,以促使物证理化检验中的种属认定转变为事实上的同一认定。     

常见蔬菜、调料、空白脏器对硫靛反应化学检验氟乙酰胺干扰的实验研究

氟乙酰胺类鼠药(含氟乙酸,氟乙酸钠)是水溶性毒物,极性大,毒性也大.中毒死亡后在体内含量呈微.人及动物死亡后,难以用常见的TLC方法进行分析.几年来,经改进后的硫靛反应化学法,一直在各实验室办案中应用.该法对氟乙酰胺类鼠药中毒案件鉴定起了很大作用.但经过多年的研究实验及案件应用,笔者认为硫靛反应不是氟乙酰胺鼠药的专属性反应,有干扰,方法灵敏度低.仅靠该法出现阳性结果和阴性结果,均不能对检材作肯定或否定结论,应配合其它方法或案情进行综合评价.     

Printed artificial sweat as replacement for natural fingermarks: Qualitative and quantitative approach considering an amino acid reagent

The study presented in this paper aims at assessing how printed fingermarks can be used to generate realistic latent marks bearing varying quantities of materials to be detected. Considering dilution series of artificial sweat (eccrine secretion) and 1,2-indanedione/zinc as amino acid reagent, we assessed how printed marks behave in comparison to natural fingermarks provided by a set of 30 donors. The results were assessed in terms of relative intensity (contrast, luminescence) and expert grading (ridge details, overall quality). With regards to the set of 30 donors, this study brought a quantitative look to the influence of intra- and inter-variability on the relative intensity values observed when processing natural fingermarks. This provided new data to further understand the concept of “donorship”. With regards to the use of printed marks, it has been illustrated how dilution series of a concentrated solution allows covering a range of cases: unnatural marks (intensity values well above those obtained with donors), rich marks (corresponding to fingermarks left by good donors), and faint marks (associated with the kind of results observed with poor donors). Such a range of detection performance offers the possibility to generate fine-tuned detection exercises of varying difficulty levels. Printed items made of artificial sweat could hence constitute a valuable alternative to natural secretions in the context of education and proficiency testing.     

Chemical enhancement of footwear impressions in blood on fabric – Part 1: Protein stains

A range of protein stains were utilised for the enhancement of footwear impressions on a variety of fabric types of different colours with blood as a contaminant. A semi-automated stamping device was used to deliver test impressions at a set force to minimise the variability between impressions; multiple impressions were produced and enhanced by each reagent to determine the repeatability of the enhancement. Results indicated that while most protein stains used in this study successfully enhanced impressions in blood on light coloured fabrics, background staining caused interference on natural fabrics. Enhancement on dark coloured fabrics was only achieved using fluorescent protein stains, as non-fluorescent protein stains provided poor contrast.A further comparison was performed with commercially available protein staining solutions and solutions prepared within the laboratory from the appropriate chemicals. Both solutions performed equally well, though it is recommended to use freshly prepared solutions whenever possible.     

Buying treaties with cigarettes: Internal side‐payments in two level games

Two‐level games models predict that domestic division within a state can alter the extent to which that state is able to reach agreements with other states, and also alter the content of any agreement that is reached. I extend the model by introducing internal side‐payments composed of unrelated domestic issues. Domestic opposition to an international agreement will inhibit cooperation most when the executive and median legislators are in relative agreement about other salient domestic political issues. Domestic opposition to an international agreement will inhibit cooperation least when the executive and median legislators are in relative disagreement about other salient domestic political issues. U.S. ratifications of the NAFTA and the Chemical Weapons Convention illustrate that not all types of domestic division inhibit international cooperation—some can facilitate it     

Background survey of polyethylene in the Australian Capital Territory – A demonstration of variability in isotopic abundance values and their application to forensic casework

Plastics including adhesive tapes, cable ties, and packaging are common evidence types encountered in forensic investigations and casework. Traditional examination techniques such as Fourier Transform Infrared (FTIR) spectroscopy lack specificity and are unable to discern differences within the same polymer structures leaving the analyst with a generic identification. High quality manufacturing methods further amplify the limitations in detecting variability between samples. Isotope Ratio Mass Spectrometry (IRMS) has been shown to be a valuable technique in further discriminating plastics. Discrimination is achieved by analysing the relative abundances of stable isotopes within a sample, with differences detected in isotope ratios possibly attributed to the source of raw materials and fractionation during the manufacturing process. A survey of cling wraps and re-sealable zipper storage bags collected in the Australian Capital Territory was undertaken to assess the variability in carbon and hydrogen isotope ratios of different brands and samples. The results of this research are discussed, particularly with respect to within and between brand trends, and a case study is presented as an example of the value of including IRMS in a casework context.     

The Role of the Chemical Weapons Convention in Countering Chemical Terrorism

A series of incidents over the past two decades has indicated that some terrorist groups are interested in acquiring and using improvised chemical devices (ICDs). Although the 1993 Chemical Weapons Convention (CWC) is a disarmament treaty that is legally binding only on sovereign states that join it voluntarily, the Convention fortuitously includes several provisions that can help its members to prevent chemical terrorism or to manage the consequences of an attack. This article examines the articles of the CWC that are relevant to counterterrorism and discusses how their implementation could be improved at the national and international levels. The article also addresses the role that the CWC secretariat, the Organization for the Prohibition of Chemical Weapons (OPCW) in The Hague, currently plays in preventing and responding to incidents of chemical terrorism, and the political factors that constrain its activities in the counterterrorism field.     

超高效液相色谱法比较鲜川芎和川芎药材中6种成分含量

目的 采用超高效液相色谱法(ultra-high performance liquid chromatography, UPLC)比较鲜川芎和川芎药材中6种活性成分(川芎嗪、阿魏酸、洋川芎内酯I、洋川芎内酯H、洋川芎内酯A、藁本内酯)的含量差异,为该药材的产地加工提供实验依据。方法 采用75%甲醇超声提取,UPLC测定鲜川芎和川芎药材中6种活性成分,根据样品处理条件计算质量分数并进行比较。流动相为乙腈(A)-0.1%甲酸水溶液(B),梯度洗脱,流速为0.2 mL/min,检测波长为294 nm,柱温30 ℃,进样体积2 μL。结果 经检测,阿魏酸、藁本内酯、洋川芎内酯A为鲜川芎和川芎药材的共有成分,鲜川芎中未检测到洋川芎内酯I及洋川芎内酯H。鲜川芎样品中各成分的质量分数为阿魏酸0.003 9%、洋川芎内酯A 0.006 4%、藁本内酯0.54%;川芎药材中各成分的质量分数为阿魏酸0.088%、洋川芎内酯I 0.20%、洋川芎内酯H 0.031%、洋川芎内酯A 0.76%、藁本内酯 1.3%。结论 川芎药材与鲜川芎中化学成分存在差异,推测在川芎的产地加工及贮藏过程中存在成分的转化。     

超高效液相色谱-四级杆飞行时间串联质谱快速分析复方守宫散化学成分及血中移行成分

目的 采用超高效液相色谱-四级杆飞行时间质谱(ultra-performance liquid chromatogra-phy/quadrupole time-of-flight-tandem mass spectrometry,UPLC-Q-TOF/MS)对复方守宫散中化学成分及其血中移行成分进行定性分析,为该制剂的...