打印复印文件朱墨时序表观特征初探

本文详细介绍了一案例的检验过程,并通过简单实验对激光打印、静电复印形成文件的朱墨时序的表观特征进行了粗浅的探究。总体而言,两种时序在朱墨交叉点的表观特征上具有文字与印文均完整、肉眼感觉文字均压在印文之上的共同点;在两者本质的差异点上,先朱后墨表现为交叉点的墨粉与未交叉部位一致,先墨后朱表现为交叉点的墨粉光泽度增加、具有潮湿感、以及易出现水珠状的印油积聚现象。     

激光显微捕获口腔上皮细胞的DNA分型

目的探索激光显微技术(lasercapturemicrodissectionsystem,LCM)捕获口腔上皮细胞,并进行STR-DNA分型检测的方法。方法用VERITAS显微切割仪红外低能激光显微捕获一定数量口腔上皮细胞,进行ProfilerPlus试剂盒STR复合扩增,检测DNA基因型。结果7～8个口腔上皮细胞能成功获得STR-DNA分型。3～4个口腔上皮细胞不能成功获得STR-DNA分型。结论激光显微捕获作为一种分离单个细胞的新技术,对于微量口腔上皮细胞的STR-DNA分型是可行的。     

利用暗记特征对HP系列彩色激光打印文件鉴别的研究

对激光打印文件的鉴别,尤其是彩色激光打印文件的鉴别,历来是可疑文件检验领域的难点和重点。利用暗记特征则为此类文件的鉴别提供了一种有效方法,即采用光学检验方法,对激光彩色打印文件暗记进行显现,利用暗记点阵形态特征和点阵排列含义特征等,为彩色激光打印机具的种类鉴别和个体鉴别提供了有效的鉴别依据。     

Determining Line-Crossing Sequences Between Laser Printing and Writing Pen Using Coaxial Light

Determining the application sequence of hand-written pen ink and printer toner lines has attracted significant interest in questioned document examination. This study uses coaxial light to determine line-crossing sequences, with intersections observed under a VSC600 forensic document workstation and a Leica M205A Stereo-microscope. Results show that reflected light at intersections and color contrast between intersections and nonintersections was observed when a hand-written ink line passes over a toner line, while a toner line passing over a written line appeared dull, with no color contrast. The procedure was tested under a range of conditions, such as types of writing pens and laser printers, the writer, and writing pressure, with the latter playing an important role in the evaluation. To validate the results, a 90% detection rate and 98% accuracy rate were achieved from 50 samples of blind testing, which is more effective than optical microscopy.     

A Computational Framework for Age‐at‐Death Estimation from the Skeleton: Surface and Outline Analysis of 3D Laser Scans of the Adult Pubic Symphysis

In forensic anthropology, age‐at‐death estimation typically requires the macroscopic assessment of the skeletal indicator and its association with a phase or score. High subjectivity and error are the recognized disadvantages of this approach, creating a need for alternative tools that enable the objective and mathematically robust assessment of true chronological age. We describe, here, three fully computational, quantitative shape analysis methods and a combinatory approach that make use of three‐dimensional laser scans of the pubic symphysis. We report a novel age‐related shape measure, focusing on the changes observed in the ventral margin curvature, and refine two former methods, whose measures capture the flatness of the symphyseal surface. We show how we can decrease age‐estimation error and improve prior results by combining these outline and surface measures in two multivariate regression models. The presented models produce objective age‐estimates that are comparable to current practices with root‐mean‐square‐errors between 13.7 and 16.5 years.     

“同版“印章的实验研究

制作了13枚"同版"渗透型印章和激光雕刻印章,分析了这些"同版"印章的印面特征和盖印印文特征.研究发现,相同条件下制作的"同版"印章的个体差异十分微小,如果考虑到各种盖印条件下,这些印章盖印印文特征的变化范围,"同版"印章印文的检验是十分困难的,甚至是不可能的.     

激光传真文书检验初探

利用传真文书进行犯罪以及由传真件引发的经济纠纷逐年上升。目前文书检验领域对新型激光记录传真文书的研究涉及较少，有必要通过对激光传真机的工作原理、记录方式、传真件及其传真文字特点的研究来说明现阶段激光传真文书的检验。     

The Use of Laser Microdissection in Forensic Sexual Assault Casework: Pros and Cons Compared to Standard Methods

Sexual assault samples are among the most frequently analyzed in a forensic laboratory. These account for almost half of all samples processed routinely, and a large portion of these cases remain unsolved. These samples often pose problems to traditional analytic methods of identification because they consist most frequently of cell mixtures from at least two contributors: the victim (usually female) and the perpetrator (usually male). In this study, we propose the use of current preliminary testing for sperm detection in order to determine the chances of success when faced with samples which can be good candidates to undergo analysis with the laser microdissection technology. Also, we used laser microdissection technology to capture fluorescently stained cells of interest differentiated by gender. Collected materials were then used for DNA genotyping with commercially available amplification kits such as Minifiler, Identifiler Plus, NGM, and Y‐Filer. Both the methodology and the quality of the results were evaluated to assess the pros and cons of laser microdissection compared with standard methods. Overall, the combination of fluorescent staining combined with the Minifiler amplification kit provided the best results for autosomal markers, whereas the Y‐Filer kit returned the expected results regardless of the used method.     

胚兔牙囊发育生物行为的组织形态学观察

研究胚兔的牙囊发育生物行为与人的牙囊发育是否相似 ,为人口腔疾病的研究提供模拟实验动物模型 ,采用光镜、电镜及激光扫描共聚焦显微镜对 4 3只胚兔的牙囊发育过程进行形态学观察。结果显示 ,牙囊来源于外胚间质 ,通过胚胎诱导形成牙支持组织 ,分化产生成牙骨质细胞、成骨细胞、成纤维细胞 ,形成牙骨质、固有牙槽骨、牙周韧带及其基质 ,对牙齿发育阶段具有保护和稳定作用 ,调控未来形成的牙周结构 ,在早期发育阶段首先出现 ,与人牙囊发育基本相似 ;最终牙囊在牙冠的顶部形成索引带 ,诱导继承牙萌出 ,在牙冠的根部形成牙支持组织 ,一部分牙囊细胞有程序性细胞死亡 ,以维持牙囊发育期内环境的生理平衡     

Incestuous paternity detected by STR-typing of chorionic villi isolated from archival formalin-fixed paraffin-embedded abortion material using laser microdissection

Microscopic examination of a blood clot expelled by a physically and mentally disabled woman taken to the emergency room because of genital bleeding revealed the presence of chorionic villi encircled by decidua, hemorrhage, and necrosis. In order to identify the father of the product of conception, sections of formalin-fixed, paraffin-embedded abortion material were subjected to laser microdissection: DNA extraction from chorionic villi selectively isolated from the surrounding tissues allowed successful STR-typing of fetal cells, which was otherwise prevented by excess maternal DNA. The large number of homozygous genotypes in the fetal profile suggested incestuous paternity. Analysis of reference DNA samples from male relatives excluded the woman's father, paternal grandfather, and maternal grandfather, whereas the obligate paternal alleles of the fetus were constantly present in the genotypes of the woman's brother, clearly demonstrating brother-sister incest (probability of paternity > 99.99999%).