Performance Study of a Score‐based Likelihood Ratio System for Forensic Fingermark Comparison

In this article, the performance of a score‐based likelihood ratio (LR) system for comparisons of fingerprints with fingermarks is studied. The system is based on an automated fingerprint identification system (AFIS) comparison algorithm and focuses on fingerprint comparisons where the fingermarks contain 6–11 minutiae. The hypotheses under consideration are evaluated at the level of the person, not the finger. The LRs are presented with bootstrap intervals indicating the sampling uncertainty involved. Several aspects of the performance are measured: leave‐one‐out cross‐validation is applied, and rates of misleading evidence are studied in two ways. A simulation study is performed to study the coverage of the bootstrap intervals. The results indicate that the evidential strength for same source comparisons that do not meet the Dutch twelve‐point standard may be substantial. The methods used can be generalized to measure the performance of score‐based LR systems in other fields of forensic science.     

凤丹皮总苷高效液相色谱特征指纹图谱研究

目的 建立凤丹皮总苷的指纹图谱,为科学评价及有效控制其质量提供可靠依据。方法 采用Agilent TC-C18(2)（250 mm×4.6 mm,5 μm）色谱柱;乙腈（A）-0.05%磷酸水（B）为流动相,梯度洗脱,流速1.0 mL/min,检测波长230 nm,进样容积20 μL。结果 建立了凤丹皮总苷高效液相色谱特征指纹图谱的共有模式,指定18个共有峰,统计结果显示,11批凤丹皮总苷样品高效液相色谱特征指纹图谱相似度均大于0.80。结论 建立的特征指纹图谱方法快速、准确、简便,可用于凤丹皮总苷的质量控制。     

关于指纹自动识别系统使用过程中的新思考

计算机指纹自动识别系统,是指以指纹自动处理为核心的指纹处理、管理、识别计算机系统,具有存储容量大、比对速度快、效率高、质量好、便于应用等诸多优越性。指纹自动比对系统不仅提高了速度,最主要的是提高了比中率。但系统的使用是离不开人的,其中捺印指纹入库质量、现场指纹入库特征标识准确性、系统的维护等工作都离不开技术人员,各个环节的技术员的综合能力的优劣,及对系统性能的熟悉程度,均直接影响到检索比对的结果。     

析痕迹检验在侦查中的作用

本文结合近些年来我国公安侦破工作中的一些案例,对痕迹检验在侦查中所发挥的作用进行细致深入的分析和阐述。最后,本文通过对一典型案例的分析阐述了现场痕迹在侦查破案中的综合利用。     

Evaluation of Four Fingerprint Development Methods for Touch Chemistry Using Matrix‐Assisted Laser Desorption Ionization/Time‐of‐Flight Mass Spectrometry,

Four preparation techniques for MALDI/TOF mass spectrometry were compared to determine the ability to gather intelligence for investigations through the chemical analysis of latent fingerprints, defined as “touch chemistry.” Compatible fingerprint development processes used for identification along with new techniques are necessary to evaluate touch chemistry. Ten volunteers deposited fingerprints from solvent residues containing drugs and explosives onto microscope slides. The developers included (A) fingerprint powder, (B) MALDI matrix, (C) fingerprint powder and lifting, and (D) cyanoacrylate fuming with fingerprint powder. Qualitative identification was based on ion images and spectra. The highest average detection rates (88%) were found using methods A and B. Methods C (52%) or D (18%) had limited success. Results demonstrate the importance of imaging coupled to extracted mass spectral data in detecting analytes in deposited fingerprints. Overall, the results suggest continued development of touch chemistry applications could prove useful for gathering intelligence and forensically relevant information.     

纤维物证检验技术的现状及发展

本文概述了国内外纤维物证的发现、提取和检验方法及研究进展,并针对我国不少地区刑侦部门在现场勘查和物证检验中对纤维物证重视不够等问题,提出我国纤维物证研究应以现场发现方法、综合检验技术研究及数据库建设为主要方向。     

Capturing Finger and Palm Impressions Using a Hand Cream and Thermochromatic Paper

An inkless set of finger and palm impressions has been obtained on thermochromatic paper by incorporating the protic solvent butylene glycol into a base hand cream mixture, which is rubbed into the hands for 30 sec before donation. This requires no washing of the hands before or after donation, removing many of the difficulties associated with inked impressions. In a random trial of 50 male and 50 female participants (mean age 41 years), 96 found the hand cream pleasant and easy to use and all produced identifiable finger and palm impressions. Following donation, participants continued to rub the hand cream into their hands. Impressions were visible immediately after donation and have not exhibited fading 2 years after being taken. 10% of participants produced impressions that captured third‐level detail, the variation between participants being thought to be associated with the amount of pressure applied during donation.     

谈Windows平台数据库课程教学

以多媒体为教学工具,以网络为教学平台,尝试从被动教学向自主学习过渡的新的教学模式,从学生的反馈中可以看出是有效的.在教学中也启发了我们把校园网络应用于教学的思路,建立适合我院教学特色的网络教学平台,使其服务于计算机教学,以满足起点各异的学生,并逐步向其他学科提供我们的经验和为其搭建新的网络教学环境.     

New optimized DNA extraction protocol for fingerprints deposited on a special self-adhesive security seal and other latent samples used for human identification

Abstract: Obtaining complete short tandem repeat (STR) profiles from fingerprints containing minimal amounts of DNA, using standard extraction techniques, can be difficult. The aim of this study was to evaluate a new kit, Fingerprint DNA Finder (FDF Kit), recently launched for the extraction of DNA and STR profiling from fingerprints placed on a special device known as Self‐Adhesive Security Seal Sticker^® and other latent fingerprints on forensic evidentiary material like metallic guns. The DNA extraction system is based on a reversal of the silica principle, and all the potential inhibiting substances are retained on the surface of a special adsorbent, while nucleic acids are not bound and remain in solution dramatically improving DNA recovery. DNA yield was quite variable among the samples tested, rendering in most of the cases (>90%) complete STR profiles, free of PCR inhibitors, and devoid of artifacts. Even samples with DNA amount below 100 pg could be successfully analyzed.