二氧化钛显现手印研究

目的建立应用二氧化钛的小微粒悬浮液来显现潜在手印的方法。方法选择6种不同客体,分别取普通汗和皮脂汗手印各40枚,各保存1天和7天,用二氧化钛小微粒悬浮液进行手印显现。结果保存1天和7天的汗潜手印显现结果没有很大区别,但皮脂汗手印显现效果好于普通汗手印。结论二氧化钛的小微粒悬浮液可以有效地显现出光滑非渗透性客体表面的潜手印。     

Reactions of latent prints exposed to blood

We explored whether an undeveloped latent print (fingermark) exposed to blood and later developed by enhancement with blood reagents such as amido black (AB) or leucocrystal violet (LCV) could appear as a genuine blood mark. We examined three different experimental conditions. In Experiment I, fingermark residue only was tested, as a control to confirm that fingermark residue alone does not react with the blood reagents AB and LCV. Experiment II investigated whether latent fingermarks exposed to blood dilutions could be treated with AB or LCV and subsequently appear as a genuine blood mark enhanced with AB or LCV. Experiment III tested whether latent fingermarks exposed to whole blood could be processed with AB or LCV and subsequently appear as a genuine blood mark enhanced with AB or LCV.The present study found that indeed, fingermark residue alone does not react with the blood reagents AB and LCV. In Experiment II, an interaction occurred between the fingermark residue and the diluted blood that caused the ridges to appear a red color. In the present study, this interaction is called a faux blood mark. While the faux blood mark phenomenon occurred most often following exposure to diluted blood, it did not occur consistently, and a predictable pattern could not be established. However, the reaction occurred more frequently following extended fingermark residue drying times. Faux blood marks are distinguishable from genuine blood marks prior to enhancement with blood reagents. Following treatment with blood reagents, it became increasingly difficult to determine whether the enhanced mark was a genuine blood print or a latent fingermark exposed to diluted blood. Latent fingermarks exposed to whole blood often resulted in a void prior to enhancement, but following treatment with blood reagents, were difficult to distinguish from a genuine blood mark enhanced with blood reagents.     

“502”真空熏显手印技术的应用现状

在我国,“502”加温加湿熏显手印技术已广为普及,但“502”真空熏显手印技术人们了解很少。本文通过介绍“502”熏显手印技术的发展,着重介绍真空熏显方法的特点。     

Illicit deals in cultural objects as crimes of the powerful

Research with dealers at the market end of the global chain of supply of cultural objects leads to the suggestion that the analytical framework associated with the concept of ‘crimes of the powerful’ can be useful in helping us to understand the role of dealers in driving the market, and in focussing our attention on the difficulties of engaging with the illicit trade through a conventional criminal justice approach. This paper explores the nature of the power that is associated with high-level antiquities dealers, and considers its regulatory implications.     

Use of an optimized 1,2-indanedione process for the development of latent prints*

1,2-Indanedione belongs to a class of compounds which have demonstrated great potential in the processing of latent prints, particularly in the area of fluorescence. However, variability in results achieved worldwide has precluded it from being used extensively. In order to isolate the cause of this variability, various components of the formulation were analyzed, including purity level of the indanedione, type of carrier solvent, and the use of ZnCl(2) both as a secondary application and incorporated into the reagent. Using a resultant optimized formulation (Ind-Zn), performance comparisons were then made in the areas of visible color development, fluorescence, and degree of substrate staining with those of 1,8-diazafluoren-9-one (DFO) for both fresh and aged prints. Moisture content of the paper substrates on which the prints had been deposited was measured and a correlation found with percentage ambient relative humidity (% RH). Determination of visible color and fluorescence as it corresponded to percentage moisture content allowed for defining critical threshold levels necessary for achieving optimal results. Correlating these values with % RH then allowed for the development of standard operating procedures for obtaining best possible print development. Through this work, it was determined that a 7.4% v/v formulation of Ind-Zn having petroleum ether as a carrier solvent yielded the most optimal results when processing methods optimized for % RH in the laboratory were utilized. Both initial color development and fluorescence were superior to that of DFO; prints developed with Ind-Zn were a minimum of 6.5 units dE* darker and more red than with DFO for all substrates tested. Processing with Ind-Zn on the majority of the substrates examined yielded fluorescence intensity values approximately four times greater than with DFO.     

纸张上手印的DFO-茚三酮-物理显影液系列显现方法研究

目的 提高纸张上手印显现率.方法 采用DFO-茚三酮-物理显影液系列显现法,比较每一显现步骤的指印显现率.结果 每一显现步骤均能提高手印显现率.结论 DFO-茚三酮-物理显影液系列显现法有效提高纸张上手印的显现率.     

京尼平显现渗透性客体上潜在手印方法研究

目的介绍一种能够用来显现潜在手印的新型物质—京尼平。方法依据京尼平能和手印遗留物质中的氨基酸或蛋白质发生反应,生成一种有荧光效应的多聚体深蓝色物质,通过自然光或多波段光源下显现观察,并将其与传统的茚三酮、DFO显现进行比较。结果京尼平显现法的显现条件与茚三酮类似,其处理后的潜在手印既在自然光下可见又在多波段光源的激发下有荧光现象。结论京尼平显现法可用于渗透性客体上潜在手印的显现。     

四氧化钌显现潜手印研究

目的探索显现潜手印的新方法。方法通过实验研究提出四氧化钌显现方法。结果对遗留在白纸、报纸、玻璃及木板等4种客体上的新鲜及陈旧潜手印的显现实验，得出比较理想的显现效果。     

DMAC显现化学类纸张上汗潜手印的方法

目的找到一种显现化学类纸张上汗潜手印的有效方法。方法制作DMAC显现试剂并进行大量比对实验、外延实验。结论用该方法操作简便、效果较好。     

Development of latent fingermarks by aqueous electrolytes

In this work we present our observations on the interaction between metallic (copper, aluminum, iron, brass, zinc) and non-metallic (glass and plastic) surfaces bearing latent fingermarks and several aqueous electrolytic solutions. Good quality fingermarks could be observed on some of the metallic and even on non-metallic surfaces after such treatment. The influence of factors such as time interval from deposition, pH of the electrolytes, wiping the latent marks prior to processing and the presence of a second metal on the quality and permanence of the developed impressions have been studied. As a rule, sebaceous marks provided much better quality impressions on all the surfaces. Initial explanations based on electrochemical processes are suggested.     

Development of latent fingermarks on thermal paper: Preliminary investigation into use of iodine fuming

Thermal paper finds its extensive use in the modern day life and could act as a vital piece of physical evidence carrying latent fingermarks. A large number of citations are available in literature suggesting various techniques to develop these marks but all are suffering with one or the other drawbacks such as complex and cumbersome procedure, pre- or post-treatment, background coloration and efficiency to develop aged fingermarks. In present study, a very simple and novel method involving iodine fuming has been suggested to develop fingermarks which were not only permanent but also without any background coloration. The suggested method does not involve any pre- or post-treatment of the substrate and was able to develop very old fingermarks (upto >1 year). In this study an attempt has been made to explain the reaction mechanism of the process. In case of different types of thermal papers, presence of different substituents on leuco dye (lactone ring) structure resulted in development of different colored fingermarks upon reaction with iodine. Sebaceous material laden marks have been found to be more intensely developed as compared to eccrine marks, and the difference was more pronounced in case of aged fingermarks.     

一种水下金属物证探测器的设计

目的 设计一种水下金属物证探测器,用于公安人员在池塘、沟渠、水井等水域中搜寻金属类物证.方法 采用金属探测技术、水下视频采集技术和无线传输技术相结合,实现探测器的多功能特性.结果 在深度不超过4m的水域中,借助探测器可以准确搜寻到金属物证.结论 该探测器具有金属探测以及视频图像采集、无线发送和保存的功能,能满足一定范围内搜寻水下金属物证的工作需求.     

Development of latent fingerprints on metallic surfaces using electropolymerization processes.

We propose a new process for developing latent fingerprints on metal items, applicable to unfired weapons made of Ergal in particular. The method is based on the presence of fatty acids that are contained in fingerprints and act as an insulator on the surface where fingerprints are to be developed. The process of polymerization occurs on the metal portions left untouched by finger contact. Hence, the developing process results as a negative pattern of the original fingerprint. The reaction consists in the electropolymerization of pyrrole and substituted porphyrins, i.e., tetra (o-aminophenyl) porphyrine: radical-cations are generated on superficial nucleation sites by oxidation of monomer, close to the electrode surface; subsequently, the radical species react with the neutral monomer, which begins to diffuse to the electrode. We have also studied the polymer's morphology by means of SEM and AFM, in order to find a correlation between the reagent to be used and the quality of the enhancement process. These are only preliminary results; however, they show that the suggested method is a new way to increase the rate of success in developing latent fingerprints on metal surfaces. In this regard, it may be considered complementary to other conventional procedures, due to the low costs of the instruments and reagents, and the rapidity and simplicity of the treatment.     

荧光黄湿粉显现手印方法的初步研究

目的研发一种具有荧光特性的黄湿粉,以提取遗留在不同客体上的不同种类的手印。方法在100mL温水中加入适量的表面活性剂,溶解后加入100g荧光黄颜料,选用不同种类客体及不同种类物质手印进行显现实验,比较显现效果;结果遗留在光滑非渗透性客体及半渗透性客体表面的汗潜、油潜手印,显出的手印纹线流畅、反差强、荧光强;结论荧光黄湿粉可适用于光滑非渗透性客体及半渗透性客体表面新鲜或较新鲜汗潜手印、油潜手印及血潜手印的显现。     

氨基黑显现常见客体上潜血足迹研究

目的研究氨基黑显现潜血足迹所适用的常见客体。方法选择14种常见客体,制作潜血足迹样本,用氨基黑进行显现。结果浅色非渗透性客体的效果优于其他客体。结论氨基黑可以很好的显出某些渗透性客体和非渗透性客体表面的潜血足迹。     

浅色调湿粉显现手印方法的研究

目的探索新的手印显现方法,祛除传统手印显现方法对使用者的健康危害;方法用浅色调湿粉采用不同操作对不同客体表面手印、不同物质手印及不同遗留时间手印进行显现,通过显现效果的比较,得出湿粉显现手印的适用范围、最佳操作方法及其显现效果;结果显出的手印清晰、流畅,与背景反差强;结论该方法适用于光滑非渗透性客体表面及潮湿或粘性表面的汗潜、油潜、蛋白手印的显现,使用方便有效。     

Finger prints on human skin--results of a general applications-oriented series

Numerous methods have been described for making dactyloscopic traces visible on human skin, but these have never become routine--last but not least because they are too complicated and time-consuming to perform. The purpose of the present investigation was to find out to what extent fingerprints on the skin of deceased persons can be made visible with the help of conventional methods like iodine fuming or brushing with Magna-Brush and can be preserved with gelatine film or moulding material. Of the total number of 486 experimental fingerprints the dermal ridges could be made visible in 150 prints. The best findings were obtained when the trace had been applied several hours post mortem. On the skin of the extremities better results could be achieved than on the trunk or the neck. Dactyloscopic tracing on the skin of bodies in homicide cases should be taken into consideration especially if there is evidence that the perpetrator touched the victim after his/her death (e.g. if the body was transported).     

Hate crimes on campus: racial/ethnic diversity and campus safety

Colleges and universities across the US have prioritized minority enrollments in their recruitment strategies, but theories offer to possible outcomes of increasing diversity on campus-increased racial harmony or increased racial tension. This study examines the impact of racial diversity on the reported number of hate crimes that occur on campus. Findings suggest that those schools that are most successful in recruiting the hardest to recruit minorities (Black and Latino students) report fewer hate crimes on campus. Implications for campus climate and racial dynamics on campus, as well as future research, are discussed.     

荧光免疫法在显现吸烟者汗潜指印领域的应用

传统的指印显现方法虽简便易行,却存在灵敏度及分辨率不够高、对现场勘查人员的身体有害等问题,为检验鉴定工作造成一定的困难。因此,需要开发新型的显现方法,以克服上述困难。本文介绍了针对吸烟者汗潜指印中存在的尼古丁代谢产物-可替宁,利用抗原抗体反应进行指印显现的技术,经过处理的指印在特定波长紫外线的激发后即可显现出指印纹线,同时还能确认指印遗留者个人生活信息,不失为一种指印显现领域的新探索。