Nanoscale analysis of the interaction between cyanoacrylate and vacuum metal deposition in the development of latent fingermarks on low-density polyethylene

Vacuum metal deposition (VMD) has been previously demonstrated as an effective development technique for latent fingermarks and in some cases has been shown to enhance prints developed with cyanoacrylate (CA) (superglue) fuming. This work utilizes scanning electron microscopy (SEM) to investigate the interactions of the two development techniques when applied to latent fingermarks on low-density polyethylene. CA is shown to act principally on the eccrine deposits around sweat pores, where polymerization results in long polymer fibrils a few 100 nm in width. Subsequent VMD processing results in additional areas of development, for example, between pores. However, the primary mode of deposition of zinc is by interaction with the polymerized CA, the fibrils of which become decorated with zinc nanoparticles. Areas with limited CA deposition and no significant polymerization are also enhanced with the VMD process, resulting in increased print development.     

Sexual Dimorphism in Finger Ridge Breadth Measurements: A Tool for Sex Estimation from Fingerprints

Previous research has demonstrated significant sexual dimorphism in friction ridge skin characteristics. This study uses a novel method for measuring sexual dimorphism in finger ridge breadths to evaluate its utility as a sex estimation method from an unknown fingerprint. Beginning and ending in a valley, the width of ten parallel ridges with no obstructions or minutia was measured in a sample of 250 males and females (N = 500). The results demonstrate statistically significant differences in ridge breadth between males and females (p < 0.001), with classification accuracy for each digit varying from 83.2% to 89.3%. Classification accuracy for the pooled finger samples was 83.9% for the right hand and 86.2% for the left hand, which is applicable for cases where the digit number cannot be determined. Weight, stature, and to a lesser degree body mass index also significantly correlate with ridge breadth and account for the degree of overlap between males and females.     

Latent Fingermark Aging Patterns (Part IV): Ridge Width as One Indicator of Degradation

This fourth article of the series is taking an in‐depth analysis at the visible aging of latent fingermarks regarding changes in ridge widths over time. The objective is to quantify and statistically describe significant ridge size variations under controlled indoor conditions. The effect of three environmental variables are examined: type of secretion (sebaceous‐ and eccrine‐rich) and type of substrate (glass and polystyrene) when aged in three light conditions (direct natural light, shade, and dark). Prior to width measurements, fresh and aged fingermarks were powdered with titanium dioxide (TiO₂) and sequentially photographed at predetermined times over 6 months. Three independent observers measured the ridges from thirty predetermined locations using strategically placed intersecting lines on the print. Results indicate that fingermarks deposited on glass are more resilient to degradation compared with those deposited on plastic. The presence of direct natural light plays a negligible role on degradation compared to secretion and substrate types.     

现场遗留手印的分析与判断

随着新刑事诉讼法修改案的实行,法律赋予了犯罪嫌疑人更多人权的同时,给公、检、法机关的工作提出了更高的要求,并就证据的形式,证据的获取途径以及证据链等关于证据的法律效力方面做出了严格的规定和要求。随着社会的发展,各种形形色色的案件层出不穷,而真正留在现场的完整指印将少之又少,如何对现场手印进行分析和判断为侦查提供重要线索,文章结合实践总结出对现场手印分析的工作步骤和方法,以便锁定犯罪嫌疑人成为法庭审判予以采信的重要物证同时也能成为犯罪情报资料的重要来源。手印作为七种证据之一,在今后的打击犯罪和参与刑事诉讼方面仍将发挥重要作用,因此研究手印仍具有实战指导意义。     

Outcome of sex determination from ulnar and radial ridge densities of Brazilians’ fingerprints: Applying an existing method to a new population

Fingerprints do not repeat, varying from region to region on the same fingerprint and from person to person. Using this morphological exclusivity in the individualization of people is considered one of the most reliable methods of identification worldwide. Many populations have been studied with respect to sex determination from fingerprints. In this study, the ridge density from two different areas - ulnar and radial - of the ten fingerprints from 100 Brazilian men and 100 Brazilian women was ascertained and statistically analyzed. The aim was to check whether these characteristics depended on sex to distinguish them categorically. Women had significantly higher ridge density in both areas for the fingers analyzed globally. Sometimes, men and women showed statistically significant differences in hands and fingers. From ulnar and radial ridge densities, this research developed thresholds for sexual discrimination cases of human identification in Brazil.     

论残缺指印的特点及鉴定方法

指印是手指末节皮肤乳突花纹遗留的印痕,能反映出手指末节形态的结构特征和乳突花纹的结构特征。在司法实践中,残缺指印的出现率很高,而且由于指印面积小,其纹型难辨,纹线数量少、细节特征少,检验残缺指印比较困难,用常规的鉴定方法难以完成。根据残缺指印的形成特点及鉴定条件从细微处入手、分析形成的原因,通过比对可以得出准确的检验结论。     

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。     

尸体与活体指纹微观细节特征的差异分析

目的比较尸体与活体指纹的微观细节特征差异,以帮助判断指纹的状态属性。方法用VSC-5000文检仪在放大15~30倍的条件下,观察比较尸体与活体指纹的微观细节特征。结果尸体与活体指纹的乳突纹线的边缘形态、宽窄及汗孔印等微观细节特征存在差异。结论指纹的微观细节特征是尸体与活体指纹种属鉴别的重要依据之一。     

纹线中空特征在指纹比对中的应用

目的探讨纹线中空特征应用于某些残缺、特征数量不足的指纹检验中的可行性。方法引入指纹三级特征理论,从该特征的存在机理、稳定性特点及与其它类似特征的区别等进行观察。结果纹线中空特征稳定存在,且在比对工作中具有可操作性。结论纹线中空特征是对常规特征的补充,对指纹比对工作具有实际意义。     

中日出口结构测度及影响因素研究——基于出口复杂度角度

使用出口复杂度指数,利用1995年—2014年《标准国际贸易分类》三位码数据,从产品层面、产业层面及国家层面测度中日制造业产品出口结构,并通过岭回归解析两国出口复杂度影响因素。研究发现:在产品结构方面,中、日出口分别集中于中低、中高复杂度产品;在影响因素方面,人力资本、研发支出对中日均有显著影响,人口规模对两国均无显著影响,FDI与加工贸易对中国有显著正向影响,人均GDP对日本有显著正向影响。