乳突纹线局部形态特征在手印检验中的应用

在手印检验工作中,通过对乳突纹线局部形态特征的种类、特点及检验方法进行研究,并运用实际案例进行分析阐述,论证该类特征在手印检验中具有可操作性,能够提高残缺、少特征等疑难手印的利用率。乳突纹线局部形态特征的应用是对常规特征的重要补充,对手印检验工作具有实际意义。     

Forensic identification science evidence since Daubert: Part I--A quantitative analysis of the exclusion of forensic identification science evidence

The U.S. Supreme Court decisions in Daubert v. Merrell Dow Pharmaceuticals Inc. and Kumho Tire Co. Ltd. v. Carmichael transformed the way scientific expert evidence was reviewed in courts across the United States. To gauge the impact of these rulings on the admission of forensic identification evidence, the authors analyzed 548 judicial opinions from cases where admission of such evidence was challenged. Eighty-one cases (15%) involved exclusion or limitation of identification evidence, with 50 (65.7%) of these failing to meet the "reliability" threshold. This was largely because of a failure to demonstrate a sufficient scientific foundation for either the technique (27 cases) or the expert's conclusions (17 cases). The incidence of exclusion/limitation because of a lack of demonstrable reliability suggests that there is a continuing need for the forensic sciences to pursue research validating their underlying theories and techniques of identification to ensure their continued acceptance by the courts.     

Initial Results on the Composition of Fingerprints and its Evolution as a Functionof Time by GC/MS Analysis

Abstract: Determining the time since deposition of fingermarks may prove necessary to assess their relevance to criminal investigations. The crucial factor is the initial composition of fingermarks, because it represents the starting point of any aging model. This study mainly aimed to characterize the initial composition of fingerprints, which show a high variability between donors (inter‐variability), but also to investigate the variations among fingerprints from the same donor (intra‐variability). Solutions to reduce this initial variability using squalene and cholesterol as target compounds are proposed and should be further investigated. The influence of substrates was also evaluated, and the initial composition was observed to be larger on porous surface than nonporous surfaces. Preliminary aging of fingerprints over 30 days was finally studied on a porous and a nonporous substrate to evaluate the potential for dating of fingermarks. Squalene was observed to decrease in a faster rate on a nonporous substrate.     

Comparative study of electrochromic enhancement of latent fingerprints with existing development techniques

To address the challenge of capturing latent fingerprint evidence from metal surfaces, a new method of latent fingerprint enhancement based on electrochromic polymer films has recently been developed. Here, we present a study comparing the development and visualization of nonvisible fingerprints on stainless steel substrates using this electrochromic enhancement approach with three classical methods (dusting, wet powder, and cyanoacrylate fuming). Two variants of the electrochromic enhancement method were utilized with polyaniline and poly(3,4-ethylenedioxythiophene) as the electrochromic materials. Fingerprint samples were taken from different donors (varying in age and gender) and were exposed to different environments for systematically varied periods of time (up to 28 days). The environments represent plausible evidential scenarios: left under ambient conditions, washed with aqueous soap solution, washed with acetone, submerged in water, and maintained at elevated temperature. The electrochromic enhancement procedure frequently outperformed the traditional methods, particularly for samples exposed to more challenging histories.     

Effect of chloride ion concentration on the galvanic corrosion of α phase brass by eccrine sweat

Inductively coupled plasma mass spectrometry measurement of the relative concentration of sodium, chloride, calcium, and potassium ions in eccrine sweat deposits from 40 donors revealed positive correlations between chloride and sodium (ρ = 0.684, p < 0.01) and chloride and calcium ions (ρ = 0.91, p < 0.01). Correlations between ion concentration and the corrosion of α phase brass by the donated sweat were investigated by visual grading of the degree of corrosion, by measuring the copper/zinc ratio using energy-dispersive X-ray spectroscopy, and from a measurement of the potential difference between corroded and uncorroded brass when a large potential was applied to the uncorroded brass. An increasing copper/zinc ratio (indicative of dezincification) was found to correlate positively to both chloride ion concentration and visual grading of corrosion, while visual grading gave correlations with potential difference measurements that were indicative of the preferential surface oxidation of zinc rather than copper.     

Study of poroscopy among South Indian population

Poroscopy is the term applied to a specialized study of pore structure found on papillary ridges of skin as a means of identification. It comes under level 3 detail of identification and hence is more reliable and accurate. The goal of this study is to estimate the importance of poroscopy for identification of individuals and to determine the gender based on frequency, type, and shape of pores. Left plain thumb prints of 200 individuals (100 men and 100 women) aged between 18 and 60 belonging to South Indian population were observed. The results have shown that women tend to have a significantly higher frequency of pores than men. Number of pores ≤ 8 pores/25 mm(2) is more likely to be of male origin and ≥9 pores/25 mm(2) is more likely to be of female origin. There was no significant sex difference based on type and shape of pores.     

指纹乳突纹线密度的性别差异初探

目的针对指纹纹线密度在不同性别间是否存在差异进行了研究和探索。方法实验对80个（其中男女各40人）中国汉族人十指纹线密度进行计数,将所得数据通过SPSS软件进行统计分析。结果指纹纹线密度均值男性少于14.5线/25mm2,女性大于等于15线/25mm2。结论男女之间指纹密度存在差异;女性指纹纹线密度较男性高。     

论纸张上潜在指印显现效果的影响因素及对策

潜在指印是目视不可见的指印反映形象,纸张上潜在指印的显现效果受造型主体及作用力大小、纸张状态及媒介物差异、遗留时间及环境条件等众多因素的影响。在实际工作中,为获取理想稳定的纸张潜在指印显现效果,必须在充分了解检材特性的前提条件下,选择与之适配的显现方法,其基本原则是先作无损显现,再选择破坏性相对较轻的有损法,最后才是可能改变检材原有理化特性的其他方法。     

一种改进的碘熏法-碘锌手印显现法

目的为解决传统碘熏法显出手印容易褪色、固定困难等问题。方法提出了一种改进的碘熏法-碘锌手印显现法，实验了不同反应物配比、不同客体材质对显现效果的影响；与常规碘熏法进行了对比实验；并考察了碘锌法显出手印的稳定性。结果碘锌手印显现法可以用于常见渗透性及非渗透性客体上新鲜汗潜手印的显现。该方法不必外加热源，携带、存储和应用更加便利；该方法显出的指纹纹线保存时间与传统碘熏法相比明显延长。结论碘锌手印显现法是一种高效、实用的手印显现方法。     

灰尘减层手印提取的实验研究

通过采用油熏法、“502”胶熏法、制模法、“502”胶碘熏法对各种客体上的灰尘减层手印提取固定进行了研究分析,并探讨了其特点、适用场合、差异的原因以及相关建议和应注意的问题.实验结果显示,这几种方法能简单、快速、有效地提取灰尘减层手印.