京尼平序列显现手印方法研究

目的考察京尼平溶液显现手印的灵敏度,并探索DFO→京尼平→茚三酮方法联用显现纸张上潜在手印的效果。方法通过使用京尼平溶液对同一手印样本进行一次、两次和三次浸泡处理,考察浸泡次数是否会影响显现效果;通过对京尼平→茚三酮、茚三酮→京尼平,京尼平→DFO和DFO→京尼平方法的组合设计方案与每种方法的单独使用进行比较研究,考察序列显现方法对显出手印的影响。结果单用京尼平溶液对同一样本进行多次浸泡在自然光和荧光模式下都不会明显增强手印的显现效果,DFO方法先于京尼平、京尼平先于茚三酮使用都能起到增强手印纹线的效果。结论京尼平方法显现手印灵敏度较高,DFO→京尼平→茚三酮方法联用可以进一步提高手印的显出率。     

京尼平与茚三酮显现手印方法的比较研究

目的对京尼平与茚三酮两种手印显现方法进行综合评价。方法用两种方法显现不同遗留客体上不同遗留时间的手印,并对显现效果、显出手印的稳定性及纸张字迹油墨扩散等现象进行考察。结果京尼平与茚三酮有着相似的的显现原理、适用范围和熏显条件,但在显现效果、显出手印稳定性、试剂成本和安全性能方面存在差异。结论京尼平相比茚三酮方法更安全、绿色环保、显出的手印稳定性更强。     

手印固有荧光的检测

目的提高手印的成功率.方法用自然光、多波段光源对五种纸张上的汗液与油脂手印进行检验.结果470纳米下的固有荧光检测对手印显现非常有效.结论手印的固有荧光检测应作为手印显现标准程序的第一步.     

京尼平溶液及其显出手印的稳定性考察

近年来国内外研究提出的京尼平方法可以用来显现渗透性纸张上的汗潜手印,如果其溶液稳定性得不到保证,必然会很大程度上影响其在实际工作中的推广应用.本文针对京尼平显现手印的方法[1-2],对溶液的保存期限以及同一批次配置的溶液的连续使用能力进行了考察,目的是为了探讨京尼平溶液的显现能力是否会随着时间的推移而发生变化,并考察手印经京尼平溶液显现后其纹线色调及荧光持续时间的变化.     

4，5-二甲基-1，2茚二酮显现纸张上手印的比较实验

笔者对3种显现手印试剂(4,5-二甲基-1,2茚二酮、茚二酮和DFO)的显现效果进行了比较实验。14,5-二甲基-1,2茚二酮荧光显现剂与茚二酮显现纸张上手印的比较1·1显现原理茚二酮与人体汗液中的氨基酸发生显色反应,经浸泡、晾干、高温处理后显出手印,在激光或多波段光源照射下观察并     

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…     

光滑客体上指印的提取

光滑客体上及变压器硅钢片上的汗液手印的提取一直是刑事技术人员研究探讨的问题，笔者通过实践，利用５０２胶贴显、罗丹明６G染色、多波段光源激发法拍到了效果较好的手印，介绍如下：１显现原理两类客体均为非渗透性客体时，手印中的汗液容易停留在客体表面。５０２胶中的氰基丙烯酸乙酯分子能与汗液成分聚合形成白色产物，潜在手印即被固定。而该聚合物对荧光染料具有优先吸附性，经染色冲洗后，只有乳突纹线处的聚合物中含有荧光染料，而该荧光染料在一定波段的光源激发下，能发出较强的荧光，从而增大了反差，获得清晰手印。２操作方…     

三种β-取代茚三酮的合成及显现汗潜手印的研究

本文基于傅克酰基化取代反应合成了三种茚三酮类似物：β-甲氧基茚三酮、β-硝基茚三酮、β-甲基茚三酮,比较并研究相同配方下三种β-取代茚三酮在不同纸张上显现汗潜手印的效果,并分别与茚三酮进行比较,分析其优劣。结果显示,三种β-取代茚三酮的显现液基本可显示不同纸张上的新鲜指纹,但β-硝基茚三酮对于陈旧指纹的显现效果较差,且显现液本身为棕褐色,显示出的指纹纹线为黑褐色,故视觉感官上稍劣于其他两者;β-甲氧基茚三酮和β-甲基茚三酮的效果均与茚三酮相当,灵敏度略高于茚三酮,显色后的稳定性高于茚三酮。研究表明,β-位取代基的变化能够改变茚三酮类化合物显现手印的效果,给电子基团的修饰能够提高该类化合物的手印显现性能,化合物本身的荧光性能与实际的指纹显现效果并不直接相关。     

酸性黄显现非渗透性客体上血潜手印初步探究

目的建立一种酸性黄显现非渗透性客体上血潜手印的方法。方法制备白色瓷砖、黑色塑料袋、黑色瓷瓶、易拉罐侧面、深色铁质茶叶盒等为客体的捺印手印,配置以酸性黄作为主要成分的染色剂,对其进行固定、染色、漂洗,在多波段光源下观察。结果在440nm激发光源条件下,通过橙色护目镜观察有很强的黄色荧光特征。结论酸性黄显现法具有操作简单、显现效果明显、能排除深色背景干扰的特点,容易推广使用。     

利用多波段光源提取皮革类客体上指纹

作为专门为法学犯罪现场勘查而设计的ST55型手提式氙灯多波段光源，可提供14个不同的输出波段光以供选择，为公安机关侦破案件、打击犯罪提供了有力帮助。其显现痕迹物证的基本原理主要包括两个方面：一是依据形成痕迹中的某些物质（如汗液手印中的汗液）在某波段输出光源的照射下，     

物理显影液显现渗透客体表面血潜手印方法研究

目的　建立了一种物理显影液显现潮湿或者浸泡渗透客体表面血潜手印的新方法。方法　把检材浸泡在配制好的物理显影液中 ,还原的银粒子吸附在血潜手印部位显现出手印纹线。结果　显现出手印纹线为黑灰色 ,纹线连贯 ,反差明显。结论　物理显影液能够有效地显现出潮湿或者浸泡后手渗透客体表面血潜手印。     

茚三酮固体介质法显现不同纸张表面潜指纹

茚三酮是显现渗透性客体上潜在汗液手印的最常用方法之一,采用微量物证提取纸和茚三酮溶液有机结合制作的茚三酮固体介质可以有效避免客体表面背景着色,不容易引起纸张油墨扩散,另外避免使用的溶剂易燃。能够更便捷的显现现场指纹,并且能够突破茚三酮只能显现渗透性客体的局限,拓宽茚三酮显现客体的范围,在热敏纸上潜指纹的显现方面有独特的应用优势。     

“502”加膜一染色法显现油质手印

目的探索方便快捷并有效的油质手印显现方法。方法用“502”熏显常见玻璃、粗糙皮革等不同客体上不同遗留时间的油汗手印和多油手印,加染后用透明胶带粘取。结果显现了30天左右大多数非渗透性客体上的油质加层手印,10天左右渗透性客体上的油质渐层手印。结论本方法适用于油质加层手印及部分油质渐层手印的显现,显出手印清晰,流畅,不破坏手印。     

The Influence of Selected Fingerprint Enhancement Techniques on Forensic DNA Typing of Epithelial Cells Deposited on Porous Surfaces

Fingerprints deposited at crime scene can be a source of DNA. Previous reports on the effects of fingerprint enhancement methods have focused mainly on fingermarks deposited in blood or saliva. Here, we evaluate the effects of fingerprint enhancement methods on fingerprints deposited on porous surfaces. We performed real‐time quantification and STR typing, the results of which indicated that two methods (iodine fuming and 1,2‐indanedione in ethyl acetate enhancement) had no effect on the quantity of DNA isolated and resultant STR alleles when compared to control samples. DNA quantities and allele numbers were lower for samples enhanced with silver nitrate and 1,2‐indanedione in acetic acid when compared to control samples. Based on DNA quantity, quality, and observable stochastic effects, our data indicated that iodine fuming and 1,2‐indanedione in ethyl acetate were the preferred options for the enhancement of fingerprints on porous surfaces.     

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.     

Microwave Selective Thermal Development of Latent Fingerprints on Porous Surfaces: Potentialities of the Method and Preliminary Experimental Results

The thermal development of latent fingerprints on paper surfaces is a simple, safe, and chemicals‐free method, based on the faster heating of the substrate underlying the print residue. Microwave heating is proposed for the first time for the development of latent fingerprints on cellulose‐based substrate, in order to add to the thermal development mechanism the further characteristic of being able to heat the fingerprint residues to a different extent with respect to the substrate, due to the intrinsic difference in their dielectric properties. Numerical simulation was performed to confirm and highlight the selectivity of microwaves, and preliminary experimental results point out the great potentialities of this technique, which allowed developing both latent sebaceous‐rich and latent eccrine‐rich fingerprints on different porous surfaces, in less than 30 sec time with an applied output power of 500 W. Microwaves demonstrated more effectiveness in the development of eccrine‐rich residues, aged up to 12 weeks.     

ABTS: a safe alternative to DAB for the enhancement of blood fingerprints

The use of 2,2'-azino-di-[3-ethylbenzthiazolinesulfonate(6)] diammonium salt (ABTS) for the enhancement of fingerprints in blood has been investigated. Optimal pH conditions and H2O2 concentrations have been determined using UV/Vis spectroscopy. ABTS is an effective and safe noncarcinogenic (though more expensive) alternative to the presently used 3,3'-diaminobenzidine (DAB) for the development of blood fingerprints, especially on porous surfaces. The bright green color of the oxidized ABTS is an advantage on certain colored surfaces where the dark brown color of DAB does not stand out well from the background. Development with ABTS does not interfere with subsequent DAB treatment, making ABTS a "nothing-to-lose" reagent. ABTS can be used after ninhydrin treatment, but the reverse is not the case.     

Fingerprint enhancement revisited and the effects of blood enhancement chemicals on subsequent profiler Plus fluorescent short tandem repeat DNA analysis of fresh and aged bloody fingerprints

This study was aimed at determining the effect of seven blood enhancement reagents on the subsequent Profiler Plus fluorescent STR DNA analysis of fresh or aged bloody fingerprints deposited on various porous and nonporous surfaces. Amido Black, Crowle's Double Stain. 1,8-diazafluoren-9-one (DFO), Hungarian Red, leucomalachite green, luminol and ninhydrin were tested on linoleum, glass, metal, wood (pine, painted white), clothing (85% polyester/15% cotton, 65% polyester/35% cotton, and blue denim) and paper (Scott 2-ply and Xerox-grade). Preliminary experiments were designed to determine the optimal blood dilutions to use to ensure a DNA typing result following chemical enhancement. A 1:200 blood dilution deposited on linoleum and enhanced with Crowle's Double Stain generated enough DNA for one to two rounds of Profiler Plus PCR amplification. A comparative study of the DNA yields before and after treatment indicated that the quantity of DNA recovered from bloody fingerprints following enhancement was reduced by a factor of 2 to 12. Such a reduction in the DNA yields could potentially compromise DNA typing analysis in the case of small stains. The blood enhancement chemicals selected were also evaluated for their capability to reveal bloodmarks on the various porous and nonporous surfaces chosen in this study. Luminol. Amido Black and Crowle's Double Stain showed the highest sensitivity of all seven chemicals tested and revealed highly diluted (1:200) bloody fingerprints. Both luminol and Amido Black produced excellent results on both porous and nonporous surfaces, but Crowle's Double Stain failed to produce any results on porous substrates. Hungarian Red, DFO, leucomalachite green and ninhydrin showed lower sensitivities. Enhancement of bloodmarks using any of the chemicals selected, and short-term exposure to these same chemicals (i.e., less than 54 days), had no adverse effects on the PCR amplification of the nine STR systems surveyed (D3S 1358, HumvWA, HumFGA, D8S1179, D21S11, D18S51, D5S818, D13S317, D7S820) or of the gender determination marker Amelogenin. The intensity of the fluorescent signals was very similar and the allele size measurements remained constant and identical to those of untreated bloody fingerprints. No additional background fluorescence was noted. Continuous exposure (for 54 days) to two of the seven enhancement chemicals selected (i.e., Crowle's Double Stain and Hungarian Red) slightly reduced the amplification efficiency of the longer STR loci in profiles of fresh and 7 to 14-day-old bloodprints. This suggests that long-term exposure to these chemicals possibly affects the integrity of the DNA molecules. This study indicates that significant evidence can be obtained from fresh or aged bloody fingerprints applied to a variety of absorbent and nonabsorbent surfaces which are exposed to different enhancement chemicals for short or long periods of time. It also reaffirms that PCR STR DNA typing procedures are robust and provide excellent results when used in concert with fluorescence-based detection assays after fingerprint identification has taken place.     

Genipin--a novel fingerprint reagent with colorimetric and fluorogenic activity

Genipin, the hydrolytic product of geniposide, which is extracted from gardenia fruit, shows good potential as a fingerprint reagent. It develops latent fingerprints on paper as blue impressions with good contrast and resolution. Even very faint impressions that are barely visible in ambient light will fluoresce brightly upon illumination at ca. 590 nm and are best viewed with a barrier filter above 630 nm. Potential advantages of genipin are the combination of colorimetric and fluorogenic activity in one reagent as well as its being a safe and environmentally friendly natural product.     

The application of infrared chemical imaging to the detection and enhancement of latent fingerprints: method optimization and further findings

Fourier transform infrared (FTIR) chemical imaging allows the collection of fingerprint images from backgrounds that have traditionally posed problems for conventional fingerprint detection methods. In this work, the suitability of this technique for the imaging of fingerprints on a wider range of difficult surfaces (including polymer banknotes, various types of paper, and aluminum drink cans) has been tested. For each new surface, a systematic methodology was employed to optimize settings such as spectral resolution, number of scans, and pixel aggregation in order to reduce collection time and file-size without compromising spatial resolution and the quality of the final fingerprint image. The imaging of cyanoacrylate-fumed fingerprints on polymer banknotes has been improved, with shorter collection times for larger image areas. One-month-old fingerprints on polymer banknotes have been successfully fumed and imaged. It was also found that FTIR chemical imaging gives high quality images of cyanoacrylate-fumed fingerprints on aluminum drink cans, regardless of the printed background. Although visible and UV light sources do not yield fingerprint images of the same quality on difficult, nonporous backgrounds, in many cases they can be used to locate a fingerprint prior to higher quality imaging by the FTIR technique. Attempts to acquire FTIR images of fingerprints on paper-based porous surfaces that had been treated with established reagents such as ninhydrin were all unsuccessful due to the swamping effect of the cellulose constituents of the paper.