X‐ray Powder Diffraction for Characterization of Raw Materials in Banknotes

We report about the X‐ray powder diffraction characterization of crystalline materials used to produce genuine and counterfeit banknotes, performed with a single‐crystal diffractometer that permits fast and nondestructive measurements in different 0.5‐mm sized areas; 20‐euro denomination genuine banknotes were analyzed, and results were compared with counterfeit banknotes. The analysis shows that the papers used to print real banknotes are composed, as expected, of cotton‐based cellulose and titanium dioxide as crystalline additive, but different polymorphs of TiO₂ for different emission countries are evidenced. The counterfeit banknotes are composed of cellulose based on wood pulp; moreover, an unexpected significant quantity of TiO₂ was found to be mixed with calcite, indicating that the paper employed by forgers is not simply a common low‐cost type. The crystalline index and intensity ratios between the peaks attributable to cellulose and fillers can provide additional information to trace back paper suppliers for forensic purposes.     

The Analysis of Black Powder Substitutes Containing Ascorbic Acid by Ion Chromatography/Mass Spectrometry*†

Abstract: Black powder substitutes containing ascorbic acid are a group of low explosives that utilize ascorbic acid as the fuel. The analysis of these powders is complicated by the degradation of ascorbic acid which occurs rapidly in solution and may also occur as the powder ages. Aqueous extracts of both intact powders and postblast residues were analyzed by an existing ion chromatography/mass spectrometry (IC/MS) method used at the Bureau of Alcohol, Tobacco, Firearms and Explosives. Results have shown that while ascorbic acid itself is not detected in this method, its diagnostic degradation products (threonic acid, monohydrated diketogulonic acid, and oxalic acid) can be identified. In addition, anions from the inorganic oxidizers (perchlorate and nitrate) and combustion products such as chloride, chlorate, and nitrite, can be identified within the same experiment. While this IC/MS method shows promise, future modifications are necessary because of limitations in identifying threonate in postblast residues, as well as coeluting compounds observed in postblast residues.     

行政任务的多元化与行政法的结构性变革

现代社会的转型,尤其是城市化的推进,显著地引致了行政任务的扩展及其任务结构的转变。行政任务的数量、范围,以及内涵发生了变革性的扩张。传统行政法模式已然难以应景式地阐释和消解诸多现代性行政法问题。适应行政任务的多元化,现代行政的作用手段和组织形态因而呈现有别于传统的、多样化的特征。现代行政法因而面临结构性的变革,以回应社会发展对行政任务多元化的诉求。在一定程度上实现从控制行政权取向的行政法学向行政任务取向的行政法学的转变,则成为现代行政法发展的一种趋势。     

Chemical Enhancement Techniques of Bloodstain Patterns and DNA Recovery After Fire Exposure*

Abstract: It is common in forensic casework to encounter situations where the suspect has set a fire to cover up or destroy possible evidence. While bloodstain pattern interpretation, chemical enhancement of blood, and recovery of deoxyribonucleic acid (DNA) from bloodstains is well documented in the literature, very little information is known about the effects of heat or fire on these types of examinations. In this study, a variety of known types of bloodstain patterns were created in a four‐room structure containing typical household objects and furnishings. The structure was allowed to burn to flashover and then it was extinguished by firefighters using water. Once the structure cooled over night, the interior was examined using a bright light. The bloodstains were evaluated to see if the heat or fire had caused any changes to the patterns that would inhibit interpretation. Bloodstain patterns remained visible and intact inside the structure and on furnishings unless the surface that held the blood was totally burned away. Additionally, a variety of chemical techniques were utilized to better visualize the patterns and determine the possible presence of blood after the fire. The soot from the fire formed a physical barrier that initially interfered with chemical enhancement of blood. However, when the soot was removed using water or alcohol, the chemicals used, fluorescein, luminol, Bluestar^®, and Hemastix^®, performed adequately in most of the tests. Prior to DNA testing, the combined phenolphthalein/tetramethyl benzidine presumptive test for the presence of blood was conducted in the laboratory on samples recovered from the structure in an effort to assess the effectiveness of using this type of testing as a screening tool. Test results demonstrated that reliance on obtaining a positive presumptive result for blood before proceeding with DNA testing could result in the failure to obtain useful typing results. Finally, two DNA recovery methods (swabbing the stain plus cutting or scraping the stain) were attempted to evaluate their performance in recovering samples in an arson investigation. Recovery of DNA was more successful in some instances with the swabbing method, and in other instances with the cutting/scraping method. Therefore, it is recommended that both methods be used. For the most part, the recovered DNA seemed to be unaffected by the heat, until the temperature was 800°C or greater. At this temperature, no DNA profiles were obtained.     

Location of Artifacts Deposited by the Blow Fly Lucilia cuprina After Feeding on Human Blood at Simulated Indoor Crime Scenes

Human DNA profiles can be obtained from fly artifacts (feces and regurgitant) when a fly has been feeding on biological material, sometimes 2 years after deposition. Morphological similarity between artifacts and spots of unaltered biological material make it difficult to distinguish between them, and presumptive and confirmatory forensic tests are unreliable in making the distinction. Knowing possible artifact locations will assist investigators in recognizing where DNA contamination might occur. Flies were released into a house with human blood available under a variety of different climatic and lighting conditions. The location of flies and artifacts was recorded after 72 h. It was found flies may move toward warm or well‐lit areas and deposit artifacts there, but artifacts were predominantly located around food sources and were often found in low positions. Factors such as ambient temperature, and the proximity of light and food sources, had an impact on where artifacts were deposited.     

中西警务模式演进过程之比较

由于历史和现实的特殊原因注定中国警务模式要走不同于西方警务模式的阶梯性发展,但中国50年警务模式的变迁非常相似于西方历次警务改革的轨迹和变革方向,即政治警务模式逐渐过渡到专业警务模式和反应式警务模式,最终向服务与权变警务模式靠拢。"杭州会议"以"发案少、秩序好、社会稳定、群众满意"为目标提出在全国范围内推广社区警务建设,成为对现行警务政策导向和警务模式确定具有重大影响作用的核心概念,成为新时期我国警务改革和运作的新命题。     

Suicide of an adolescent girl with sodium nitrite ordered on the internet

Nitrites are commonly used in the chemical, pharmaceutical, and food industries. Recently, they have been identified in cases of voluntary intoxication. We report the case of a 13-year-old girl who was found lifeless on her bed next to a glass containing a white powder and a bottle containing a white powder with a moistened appearance. External examination and autopsy revealed a nonspecific asphyxia syndrome, which was confirmed by the pathological analysis. Analysis of the samples revealed metoclopramide in the peripheral blood at a concentration of 0.402 mg/L (LC–HRMS). An analysis of the gastric contents was carried out after sodium nitrite was detected in the powders found near the body (Raman spectrometry). Nitrites were found in the gastric fluid at a concentration of 30.9 mg/L. Death occurred secondary to anoxia, following ingestion of nitrites; suicide kits are available on the web and nitrites are relatively easy to source and inexpensive. Nitrites are delivered in powder form to be dissolved in liquid, which may then be consumed with metoclopramide (or an alternative anti-emetic drug) to maximize absorption and reduce emesis. The toxic effect of nitrites lies in their oxidizing power, causing the transformation of hemoglobin into methemoglobin, which, when it accumulates, induces tissue anoxia resulting in death. There has been an alarming increase in the number of cases linked to suicide using nitrites or a nitrite suicide kit. The fact that nitrites are readily available online underscores the importance of establishing effective preventive measures such as limiting the access and use of this chemical.     

浅谈以“说（Talk）”为主导的高职英语课堂教学

英语教学中,培养学生的语言应用能力非常重要。“说（Talk）”是整个课堂教学过程达到教学目的主导形式。教师应当想方设法调动学生的主体意识,加大交际训练力度,使学生能够有足够的热情和信心投入到课堂语言实践活动之中。     

新型粉末状荧光502熏显手印荧光波段研究

目的运用新型粉末状荧光502可一步显现非渗透性光滑客体表面潜手印。为了选择最佳的激发光源和滤光镜来观察熏显后荧光效果,本文对该粉末的荧光性能进行研究。方法使用荧光光谱仪对新型粉末状荧光502进行激发光谱和发射光谱的测试,进而选择合适的激发光源及滤光镜来进行观察和拍照。结果新型粉末状荧光502的光谱范围较宽,在波长为235nm~580nm范围内均可进行激发,具有广谱性,其中对波长在530nm附近的激发光具有最大峰值,即荧光强度最大,对450nm和360nm附近的光也具有很高的吸收峰值,斯托克斯偏移量为45nm。宏观验证实验表明,在仪器分析所得的范围内,显现出的手印效果均较好。结论运用该粉末在熏显手印后可以在紫外、紫光、蓝光、黄光、绿光范围内进行激发,斯托克斯偏移大,荧光亮度高,在观察荧光效果时能够很好的消除背景荧光的干扰,也便于选择滤光镜。手印荧光效果除了受到熏显物质荧光性能的影响外,还与激发光源的品质、滤光片的透过性能以及检材固有的发光特点、客体表面性质有关。     

The historical evolution of settlement patterns and trends in South Africa: Unlocking the log-jam of the unsustainable settlements impasse

Abstract

This article ascertains the underlying causes of the persistence of unsustainable settlement patterns and trends in post-apartheid South Africa. Despite positive development planning policy intentions in the post-apartheid South Africa, glaring deprivation and spatial inequality has persisted. The article is grounded in a chronological analysis of demographic, functional and regional economic dynamics at the different epochs of South Africa's history as well as the settlement policy and planning intentions. Its main finding is that the persistence of unsustainable settlement patterns and trends in post-apartheid South Africa is largely a result of misplaced settlement policies and strategies. They give knee-jerk responses to global, regional, national and local dynamics shaping settlement patterns and trends. The recommendation is that development planning initiatives should be informed by the dialectics of settlement facets at local, regional, national and global levels for them to deal decisively with the historical problem of unsustainable patterns and trends.