Fluorescence of a Natural Fluorophore as a Key to Improve Fingerprint Contrast Image

The optical and morphological properties of resveratrol were investigated. This nontoxic fluorescent natural material, emitting in the visible blue light, was used as an optical marker, enabling the enhancement of the image contrast coming from relief pictures marked on challenging surfaces. By applying appropriated imaging softwares, this marker was verified to be very useful in the latent fingerprint recognition deposited on different wood surface types, mainly those with high level of roughness, where conventional forensic materials do not allow effective fingerprint image visualization.     

基于分子克隆方法制备标准分子量片段混合物

目的制备标准分子量DNA片段混合物。方法选取pMD18-T载体部分序列作为插入片段,设计引物,制备包含不同大小的标准分子量片段的克隆。大量培养细菌提取质粒,用双酶切、连接荧光接头的方法制备不同大小的带有荧光的标准分子量片段,混合,纯化,最终获得标准分子量片段混合物(内标)。结果用分子克隆方法制备出具有实用性的标准分子量片段混合物,其单个标准分子量片段大小分别为80bp、124bp、194bp、224bp、254bp、304bp、349bp、399bp、424bp、454bp。并且这些标准分子量片段混合物可以准确地对DNATyper15试剂盒的扩增产物进行检测。结论应用该方法制备了能满足研究和实验室要求的标准分子量片段混合物,为DNA分子量标准物标准品的制作提供了一种新的方法。     

Investigating the Potential of Fluorescent Fingerprint Powders as a Marker for Blow Fly Larvae (Diptera: Calliphoridae)

Four fluorescent fingerprint powders (RedWop^?, GreenWop^?, Basic Yellow^?, and Yellow Powder^?) were evaluated as a marker for blow fly larvae. Administration methods included ingestion (high vs. low concentration) or topical. Ingestion of high concentrations of Basic Yellow^? and RedWop^? caused higher larval mortality. Basic Yellow^? delayed development and adult emergence while RedWop^? and Yellow Powder^? had a significant effect on particular stages of development, however, emergence time was not altered. Optimal administration is through ingestion at low concentration levels (<10%) or topically, with GreenWop^? demonstrating minimal adverse effects. Optimum wavelength for discrimination between powders was 450 nm. This research can aid in investigative training to increase visibility of larval and pupal blow flies. It can also be used in entomological studies to differentiate between larval blow flies (or other dipteran) species or individuals to further understand complex interactions and behavior during larval development.     

文件制作时间检验的物质基础

随着科学技术的快速发展,各种新型染料、颜料不断涌现。不断发展的书写和打印材料对文件制作时间检验工作提出了越来越高的要求。寻求显色物质整体稳定中的可测定因素,探索可资利用的指标性参数,达到检验目的。这就需要我们对材料进行比较全面的认识和研究。     

Bank security dye packs: synthesis, isolation, and characterization of chlorinated products of bleached 1-(methylamino)anthraquinone

Banknote evidence is often submitted after a suspect has attempted to disguise or remove red dye stain that has been released because of an anti-theft device that activates after banknotes have been unlawfully removed from bank premises. Three chlorinated compounds have been synthesized as forensic chemical standards to indicate bank security dye bleaching as a suspect's intentional method for masking a robbery involving dye pack release on banknotes. A novel, facile synthetic method to provide three chlorinated derivatives of 1-(methylamino)anthraquinone (MAAQ) is presented. The synthetic route involved Ultra Clorox bleach as the chlorine source, iron chloride as the catalyst, and MAAQ as the starting material and resulted in a three-component product mixture. Two mono-chlorinated isomers (2-chloro-1-(methylamino)anthraquinone and 4-chloro-1-(methylamino)anthraquinone) and one di-chlorinated compound (2,4-dichloro-1-(methylamino)anthraquinone) of the MAAQ parent molecule were detected by gas chromatography mass spectrometry (GC-MS), and subsequently isolated by liquid chromatography (LC) with postcolumn fraction collection. Although GC-MS is sensitive enough to detect all of the chlorinated products, it is not definitive enough to identify the structural isomers. Liquid-state nuclear magnetic resonance (NMR) spectroscopy was utilized to elucidate structurally the ortho- and para-mono-chlorinated isomers once enough material was properly isolated. A reaction mechanism involving iron is proposed to explain the presence of chlorinated MAAQ species on stolen banknotes after attempted bleaching.     

人体脑组织RNA表达水平与早期PMI的相关性

目的探讨人体脑组织多种RNA指标的表达水平与早期死亡时间(PMI)的相关性。方法选取12例已知PMI(4.3~22.5 h)的个体,提取脑组织总RNA。选取8种常用RNA指标(β-actin、GAPDH、RPS29、18S rRNA、5S rRNA、U6 snRNA、miRNA-9、miRNA-125b),通过实时荧光定量PCR技术检测其在脑组织中的表达水平。运用geNorm软件筛选早期PMI表达稳定的内参指标,并分析其表达水平与相关因素(年龄、性别、死亡原因)的关系。运用R软件将内参标准化的RNA指标代入前期研究建立的数学模型推断PMI,计算推断PMI的误差率以验证模型精确性。结果 5S rRNA、miRNA-9和miRNA-125b表达稳定,其表达水平与年龄、性别、死亡原因无关。利用β-actin推断PMI的误差率为24.6%,GAPDH为41.0%。结论 5S rRNA、miRNA-9和miRNA-125b在死亡早期表达稳定,适合作为人体脑组织的内参指标。β-actin表达水平与PMI相关性良好,有望成为推测早期PMI的辅助指标。     

打印机打印法变造文件的检验

打印机打印法变造文件在检验中按照确定变造事实、分析变造方法、确认被变造原文字三个步骤,综合运用透射光或侧光观察、荧光检验、综合评断等方法进行分析检验。现代化办公用品、设备在侦破犯罪案件上的运用,使得实际工作中文件检验的工作对象不断发展、变化,这对文检人员提出了新的要求,即要具备坚实的理论基础,又要在工作中不断积累、不断学习、不断总结,从理论和实践上寻找解决新问题的新方法、新手段,为侦破刑事案件、澄清法律事实,发挥更大作用。     

山羊痘病毒RPO30基因绿色荧光蛋白质粒的构建及融合表达

为了研究针对山羊痘病毒RPO30的siRNAs的干扰效果,构建了RPO30基因与增强型绿色荧光蛋白(EGFP)基因的融合表达质粒,并在BHK-21细胞中表达.通过对RPO30基因进行PCR扩增,克隆入表达载体pEGFP-N1,并进行双酶切及测序鉴定;将阳性重组质粒转染BHK-21细胞,检测绿色荧光蛋白的表达和RPO30...     

口蹄疫病毒3C基因与增强型绿色荧光蛋白基因的真核共表达

为验证siRNAs对口蹄疫病毒(FMDV)复制的抑制效果,用反转录聚合酶链反应(RT-PCR)扩增Asia 1型口蹄疫病毒Jiangsu/China/2005株的3C基因,克隆入增强型绿色荧光蛋白(EGFP)表达载体pEGFP-N1中,并进行双酶切、PCR及测序鉴定。将阳性重组质粒转染PK-15细胞,检测EGFP的表达和3C基因转录水平。结果显示,经PCR及双酶切鉴定,目的基因片段大小与预期相符,测序结果与Jiangsu/China/2005株相应序列一致。荧光显微镜和流式细胞仪均检测到细胞内有EGFP表达,实时荧光定量PCR检测到细胞内有3C基因的转录。证实,成功构建了FMDV 3C基因与EGFP共表达质粒并在PK-15细胞中获得了表达。     

The detection of multiply charged dyes using matrix-assisted laser desorption/ionization mass spectrometry for the forensic examination of pen ink dyes directly from paper

Abstract:  Laser desorption mass spectrometry (LDMS) is emerging as a technique for questioned document examination. Its use is limited to detecting ink dyes that are neutral or singly charged. Several inks contain dyes that are multiply charged and LDMS cannot be employed for their identification. We have successfully detected >20 polyionic dyes that can be used in the manufacture of inks using matrix-assisted laser desorption/ionization (MALDI) MS, directly from paper, with the matrix, 2-(4-hydroxyphenylazo)benzoic acid (HABA), and the additive, diammonium hydrogen citrate (DAHC). For example, Acid Violet 49, a charged dye containing one positively-charged site and two negatively charged sulfonate groups, cannot be detected by LDMS, but forms intact, singly charged ions in the MALDI MS experiment. The method described is also useful for identifying multiply charged dye mixtures that are used in modern pen inks.