“502”胶液体显现潜手印技术的研究

目的研究探索"502"胶溶液显现手印的方法.方法以石油醚为分散剂,添加对苯二酚作为显现增强剂,配制"502"胶显现液.结果能够显现非渗透客体上油质加、减层手印、加减层混合手印及普通汗潜手印,其显现效果与"502"胶熏显法非常相似.结论该方法具有方便、快捷、灵敏等特点,是"502"胶显现手印技术的重要补充.     

“502”熏显手印过度的减薄方法

用“502”胶熏显手印是当今最普遍有效的方法,但是,用“502”胶熏显手印要受温度、湿度、时间等因素的影响,这些因素在具体操作过程中不易掌握,温度过高、湿度过大或时间过长,会使“502”单体在手印上的聚合物过多手印模糊不清。这时需对熏显过度的手印进行减薄处理,方法如下:     

减薄“502”胶印提取方法熏显过厚手

502”胶对非渗透性客体表面汗液手印显现技术在刑侦系统得到了广泛的应用。但“502”胶熏显过程中控制不好温、湿度,通常会造成显现过厚,导致“502”胶单体聚集过多,相邻的乳突线之间没有明显界限,使得熏显出手印的清晰度受到影响。为了补救,通常需要进行减薄处理。     

便携式“502”喷显仪的制作与使用

“502”熏显手印的方法,成为现场勘查中不可缺少的手印提取方法,可是在过去的勘查实践中我们发现,现有的“502”熏显仪存在一些缺陷。(1)当现场手印的承载客体过大而不能分割提取手印时,现有的仪器无法使用;(2)不便于携带,不能在现场使用,有时会贻误战机;(3)价格昂贵,影响了“502”熏显方法的普及与推广。我们经过多年的实践,试验制成一种小型的“502”现场指印喷显仪(见图1)。该仪器具有构造简单、价格便宜、携带使用方便等优点,现场上需用“502”熏显的部位都     

灰尘手印荧光增强技术

当手与客体表面接触形成灰尘手印时,手印上附着物可以遗留在客体表面,客体表面上的附着物也可以被手沾走,因此,灰尘手印中的物质成份不但含有灰尘成份而且含有汗液成份[1]。手印用“502”胶熏好后,即用荧光粉染色,或荧光染料进行染色,之后用乙醇将本底颜色冲洗掉,在紫外灯或多波段光源某一波长照射下观察其荧光手印。因为荧光粉和罗丹明6G等荧光染料对“502”聚合物有较强的优先吸附能力,从而使在自然光下观察不清的“502”聚合物亦能被染色。荧光染料由于其具有强烈的荧光效果,其染色效果较其它染料相比要高几倍甚至几十倍,在光的激发下纹…     

接触性检材502胶熏显后手印脱落细胞的DNA提取

目的建立接触性检材中手印定位、检材转移、DNA提取纯化的方法。方法 66例接触性检材经502胶熏显,手印接触部位明确后,分别采用普通擦拭法及丙酮擦拭法进行检材上手印脱落细胞的转移,并使用超微量磁珠法试剂盒提取纯化手印脱落细胞DNA,扩增后分析结果。结果用丙酮擦拭法得到的33例检材有30份获得了较好的STR分型结果,峰值范围为1 000~4 000 RFU,峰型均匀;而普通擦拭法很难获得理想的STR分型。结论通过丙酮擦拭法转移502胶熏显的手印脱落细胞,STR分型效果更优良,可应用于法庭科学实践。     

“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。     

用热水加温加湿“502”胶显现车辆内手印

笔者在工作中,摸索出一种用“502”胶显现车辆内手印的方法。这种方法适用轿车、面包车、农用车、挖掘机等各类车辆（驾驶室）内的手印显现,通过控制车内温度和湿度,“502”胶熏显速度达到一个较好的显现效果。现以柳州五菱面包车为例进行实验。     

减薄"502"胶熏显过厚手印提取方法

502"胶对非渗透性客体表面汗液手印显现技术在刑侦系统得到了广泛的应用[1].但"502"胶熏显过程中控制不好温、湿度,通常会造成显现过厚,导致"502"胶单体聚集过多,相邻的乳突线之间没有明显界限,使得熏显出手印的清晰度受到影响[2].为了补救,通常需要进行减薄处理.     

“502”熏显指印染色提取新方法

潜手印的显现方法中,“502”熏显法是近年来广泛使用的方法。但由于“502”熏显出的指印纹线呈白色,在浅色、白色客体上显出的指印反差小,不易拍照提取;同时由于“502”聚合物本身的特性,直接提取“502”熏显指印成为一大难题。目前多采用龙胆紫、孔雀绿染色照相提取的方法。在实际工作中,这两种染色液对检材要求苛刻,并且缺少补救措施。经过大量实验,我们摸索成功碘染色方法。此法操作简便,染色灵敏,染色后的指印可进一步处理变色,亦可用胶纸提取,是“502”熏显指印的理想处理方法。     

胶带粘面上的手印显现

经过比较,证明悬浮液法、碳素墨水法、染色法和物理显影液法对显现胶带粘面上的手印效果较好.     

Fingerprints as evidence for a genetic profile: morphological study on fingerprints and analysis of exogenous and individual factors affecting DNA typing

Material recovered from 374 fingerprints left by eleven laboratory workers on three different substrates (glass, wood, metal) at a standard pressure time of 30 s, with and without preliminary handwashing, was submitted to morphological, quantitative, and type analysis. Morphological and agarose-gel electrophoresis analysis showed that a non-negligible amount of epidermal corneal cells presented apoptotic alterations. The quantity of DNA recovered from fingerprints ranged between 0.04 to 0.2 ng, and in a significant number of experiments no DNA was detected. Handwashing reduced the amount of DNA recovered from fingerprints. The "shedder status" of the donor was a very important factor, causing inter-individual variations in the amount of DNA left by fingerprints. Spurious alleles from laboratory-based and secondary transfer contamination, stutters, and other artifacts described when analyzing low-copy-number DNA and capable of affecting correct profiles were observed.     

STR genotyping and mtDNA sequencing of latent fingerprint on paper

A systematic study was conducted to investigate whether DNA can be successfully extracted from latent fingerprints deposited on ordinary paper and analysed using short tandem repeat profiling and mitochondrial DNA sequencing. In order to evaluate the performance of latent fingerprint analysis in a criminal case, experiments with varying conditions were carried out to improve our understanding of low copy number (LCN) DNA typing. After optimising the extraction methods to achieve increased sensitivity, the examination of touched paper can routinely yield the STR profile of the individual who has touched it. A fingerprint can therefore be considered as a potential source of DNA for genetic identification. Nevertheless, the findings of our "after enhancement experiment" (using chemically or physically pre-treated fingerprints), and our "mixture experiment" (using fingerprints from three to four people on the same sheet of paper) help to define the limitations of the low copy number PCR technique in forensic casework.     

DNA指纹图在法医学鉴定中应用的研究(Ⅰ)

应用 MYO DNA 探针对中国人进行了 DNA 遗传指纹图检验。从两个家系16人及100个无关个体中取肘静脉血提取 DNA,用限制性内切酶 HinfⅠ或 HaeⅢ水解,1%琼脂糖凝胶电泳分离,经 Southern印迹转移,MYO DNA 探针杂交,获得了清晰可辨的 DNA 指纹图谱。结果每个个体在3.0Kb 以上均能检出10条以上杂交区带,个体间的相关概率<4×10~(-9),由杂交区带构成的图谱是个体特异的,杂交区带遵循孟德尔的显性遗传方式由亲代向子代遗传;具有 DNA Fingerprints 的特点。对两起亲子鉴定的案例进行指纹图检验,孩子所存在的杂交区带,除来自母亲外,其余可在嫌疑父亲带中找到,肯定了孩子与嫌疑人的父子关系。MYO DNA 探针在亲子鉴定与个人识别的法医学鉴定中有着重要的实用价值。     

Visualization method for fingerprints on skin by impression on a polyethylene terephthalate (PET) semirigid sheet.

Based on the phenomenon that static electricity attracts dust, a polyethylene terephthalate (PET) semirigid sheet coated with printing ink was used to visualize impressions of fingerprints on the skin of living and dead bodies. Compared with visualization methods for perspiration fingerprints, this method recovers better images for a longer time after the fingerprint has been deposited on skin. Fingerprints transferred to the PET sheet are photographed with sidelighting using an ordinary light source. For fingerprints that yield inadequate contrast, an argon-ion laser can be used to improve the contrast.     

Stable-isotope fingerprints of biological agents as forensic tools

Naturally occurring stable isotopes of light elements in chemical and biological agents may possess unique "stable-isotope fingerprints" depending on their sources and manufacturing processes. To test this hypothesis, two strains of bacteria (Bacillus globigii and Erwinia agglomerans) were grown under controlled laboratory conditions. We observed that cultured bacteria cells faithfully inherited the isotopic composition (hydrogen, carbon, and nitrogen) of media waters and substrates in predictable manners in terms of bacterial metabolism and that even bacterial cells of the same strain, which grew in media water and substrates of different isotopic compositions, have readily distinguishable isotopic signatures. These "stable-isotopic fingerprints" of chemical and biological agents can be used as forensic tools in the event of biochemical terrorist attacks.     

The development of latent fingerprints on human skin: the iodine-silver plate transfer method

With the iodine-silver plate transfer method latent fingerprints on human skin can be developed. The continuation of experiments leading to the eventual application to a bona fide case processed through a judicial system will indicate the "arrival" of a new and useful tool for the law enforcement officer in identifying the perpetrators of our more serious crimes.     

真空镀膜中膜系选择对潜手印显现的影响

目的探究在真空镀膜中不同镀膜材料能否显现出潜手印并比较不同镀膜金属显现手印的效果。方法使用不同的镀膜金属显现多种类型客体表面的潜手印。结果存在可替换镀膜材料。结论可替换镀膜金属对潜手印显现的效果良好,纹线清晰连贯,背景反差大,并对特定客体上的手印显现极具优势。     

纸张上薄膜拓印指纹检验研究

目的研究薄膜拓印指纹的特征和检验方法。方法利用塑料薄膜在纸张上进行了120次指纹拓印实验,然后比较拓印指纹和正常捺印指纹。结果成功转印出较清晰的拓印指纹41枚,发现了纸张上拓印指纹的常见特征。结论通过特征分析可以对薄膜拓印指纹进行检验。     

手印显现物理显影液的研究

物理显影液是渗透性客体上富脂手印的一种有效显现方法.本文就物理显影液显现手印的原理、方法、显现手印类型、显现客体类型、操作注意事项以及影响显现效果的各种因素作了一些探讨.