1例自制火药手枪检验鉴定后的思考

1 简要案情 2006年3月24日9时许，西安铁路公安局安康公安处站勤民警在汉中车站进行检查时，查获旅客廖某非法携带自制火药手枪1支。办案民警将查获的自制火药手枪送技术部门，要求对该枪进行技术鉴定，以确定其是否为枪支。     

实时荧光定量PCR检测羊肉制品中鼠源性成分

目的建立基于实时荧光PCR技术的肉制品中鼠源性成分的快速检测方法。方法以羊和鼠的细胞色素b基因序列设计特异性引物和Taqman荧光探针,通过特异性、灵敏性及模拟混合肉样检测实验,建立羊肉制品中鼠源性成分实时荧光定量PCR检测方法。结果该检测方法具有良好的特异性和灵敏度,在50mg羊肉和鼠肉的混合样品检测中,鼠源性成分检测限可低至1%。结论所建立的鼠源性成分检测的实时荧光定量PCR方法,为肉制品质量控制提供了有效的技术手段,弥补了利用RTi-PCR检测肉制品中鼠源性成分的技术空白。     

二组分混合DNA样品STR图谱解释

对混合样品STR图谱的结果进行解释。实验模拟二组分DNA混合样品 ,复合扩增荧光检测 10个基因座 ,比较混合样品谱带 ,计算等位基因峰面积比。结果发现 :二组分DNA混合样品的等位基因数增加 ,样品的混合比例不同就出现峰面积的不平衡。在等位基因峰面积比值与样品组分混合比例接近时 ,可由峰面积比值推断混合样品的混合比例。在混合比例为 1∶2 0时 ,基本上检测不到来自少量混合成分的等位基因 ,表现为单一组分图谱 ;在混合比例为 1∶10时 ,含量低的组分的等位基因峰面积接近与主要组分的“Stutter”峰面积 ,与来自主要组分的等位基因峰面积差异很明显。能检出混合样品中少量成分等位基因的最高混合比例为 1∶10     

混和硅油测定玻璃折射率

目的建立混合硅油测定单纯用B油和C油无法测定的玻璃折射率的方法。方法将B油和C油分别按1：2和2：3的体积比配成两种混合硅油,用此两种混合硅油测定同一块玻璃的折射率。结果用此两种硅油测得的玻璃的折射率结果无显著性差异。该方法克服了玻璃折射率仪温度范围窄（25℃～125℃）的缺点。     

东莨菪碱的GC／MS检验

目的用气质联用方法分离定性案件检材中微量的东莨菪碱成分。方法以液-液萃取法提取分离,用CP5860(CP-sil8CB)毛细管拄(30m×0.25mm×0.33!m),并采用气质联用仪(GC/MS)测定东莨菪碱。结果可检出检材中微量东莨菪碱,色谱分离良好。结论以气质联用仪(GC/MS)测定东莨菪碱方法灵敏度高,测定结果准确可靠。     

FISH联用激光捕获显微分离技术对混合斑进行分离检验

目的建立荧光原位杂交(FISH)联用激光捕获显微分离技术(LCM)精确分离男女混合斑中精子的检验方法。方法收集健康志愿者精子和女性阴道上皮细胞制备模拟混合斑,经过预处理后用Vysis CEPX SpectrumOrangeTMY SpectrumGreenTM试剂盒进行荧光原位杂交,并用PALM激光捕获显微分离系统分离男、女性细胞,使用Identifiler试剂盒结合低体积扩增技术分别对男女成分进行STR扩增。结果荧光原位杂交后,可清晰分辨混合斑中的男女细胞。捕获20个精子细胞可以得到完整的STR分型,检出率为80%。随着精子数目增多,检出率提高而等位基因丢失率降低。30个精子检出率最高,为95%。结论激光捕获显微分离联用FISH技术可用于混合斑中男女细胞DNA的分离检验。     

近距离枪弹创身入口残留物的能谱测定

对１４例近距离人体枪弹创射入口的创周皮肤和创道内组织分别作了能谱测定，结果发现，创周皮肤和创道内组织上的金属成份有着异，而与异物颗粒形态无关，创道内主要为弹头成份，创周为火药成份。     

近距离枪弹创射入口残留物的能谱测定

对14例近距离人体枪弹创射入口的创周皮肤和创道内组织分别作了能谱测定，结果发现，创周皮肤和创道内组织上的金属成份有差异，而与异物颗粒形态无关．创造内主要为弹头成份，创局为火药成份．     

乌头属植物生物碱高效液相色谱研究

目的建立高效液相色谱法测定多种乌头属植物生物碱的方法。方法XTerraTMRP185μm,(250mm×4.6mm)色谱柱;流动相为乙腈∶30mmol/L碳酸氢铵梯度洗脱;流速1.0ml/min;检测波长233nm。结果该方法可成功应用于5种乌头属植物12个样品中生物碱成分分析。结论本研究结果提示乌头属不同种植物中生物碱成分及含量差异显著,因此为确保该类中药材用药安全,提高临床疗效,必须建立严格的药材质量控制体系。     

免疫磁珠法分离混合样本中血液成分的探究

目的 基于免疫磁珠法分离脱落上皮细胞中的白细胞，消除或减弱混合检材中血液来源STR分型对结果分析的干扰。方法 分别取两名不同个体的血液和口腔脱落上皮细胞，按不同比例制备成混合样本作为实验组，并同时制备细胞量相等的对照组。应用免疫磁珠法分离实验组样本中白细胞，并与对照组以相同条件进行DNA提取、扩增、分型，对比两组STR分型结果。结果 当血液量较少时，对照组为混合STR分型，经免疫磁珠法分离混合检材中白细胞后，实验组为单一来源STR分型；当血液量较多时，此时对照组为混合STR分型，但口腔脱落上皮细胞来源的STR分型谱带峰高较低甚至丢失，经免疫磁珠法后，实验组仍为STR混合分型，但口腔脱落上皮细胞来源的STR分型谱带成为主峰；当混合样本中口腔脱落上皮细胞微量，血液占比极大时，此时对照组为血液来源的单一STR分型结果，经免疫磁珠法后，实验组为STR混合分型，包含口腔脱落上皮细胞来源的所有等位基因分型。结论 该方法可用于分离脱落上皮细胞中血液成分，降低血液来源的DNA比例，能够改善此类混合检材中目的细胞的STR分型结果，为刑事案件中含有血迹浸染的混合生物检材的检验提供了一种新思路。     

新型亲油性纳米二氧化硅粉末在手印显现中的应用

目的 比较新型亲油性纳米二氧化硅粉末显现手印的效果.方法 应用亲油性纳米二氧化硅粉末与现场勘查箱内金粉、银粉和黑色磁性粉显现非渗透性客体表面油汗混合手印,并在自然光下观察比较显现效果.结果 亲油性纳米二氧化硅粉末显现出的手印图像纹线清晰连贯,背景反差好.结论 亲油性纳米二氧化硅粉末显现手印具有一定的优势.     

Bone Mineral Change During Experimental Calcination: An X‐ray Diffraction Study

The effects of calcination (400–1200°C) on pig bones have been studied using powder X‐ray diffraction (XRD) and secondary modifications, such as color change and weight loss. The characterisation by powder XRD confirmed the presence of the crystalline phase of hydroxyapatite, and comparison of the results obtained at different temperatures suggested that at 650°C, all the organic components and carbonate substitutions were completely removed. Accordingly, these samples were white. In addition, the crystallinity degree and the crystallite size progressively increased with the calcination temperature until 650°C, remaining stable until 1200°C. Below 650°C, bone samples presented organic compounds, resulting in background noise in the diffractogram and gray or black color. In addition, impurities in the lattice correspond to low crystallite sizes.     

Development of Latent Fingermarks on Various Surfaces Using ZnO‐SiO2 Nanopowder

Fingermarks are one of the most useful forms of evidence in identification and can provide generalized proof of identity in crime investigation. They are developed using various conventional powders. The novel nanopowder ZnO‐SiO₂ was synthesized via the conventional heating method and characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), energy‐dispersive X‐ray (EDX) analysis, transmission electron microscope (TEM), and X‐ray diffraction (XRD). The mean particle size of ZnO‐SiO₂ nanopowder calculated through TEM was 32.9 nm. The development of fingermarks was carried out by powder dusting and small particle reagent (SPR) methods. Powder dusting method was used for the development of latent fingermarks on various dry, nonporous, and semi‐porous surfaces. The SPR method was also applied to wet nonporous surface. The developed latent fingermarks using ZnO‐SiO₂ nanopowder were found to have excellent quality with very clear third‐level ridges detail and had better visibility than commercially available white powder.     

Styryl dye coated metal oxide powders for the detection of latent fingermarks on non-porous surfaces

Conventional fingermark powders rely on contrast induced by absorption/reflection (e.g. black powder) or luminescence in the visible region (e.g. Blitz Green(?)). In most cases, these powders provide sufficient contrast; however, in some circumstances surface characteristics can interfere with the visualisation of powdered fingermarks. Visualisation in the near infra-red (NIR) region, however, has been shown to eliminate interferences commonly encountered in the visible region. In this study, a mixture of rhodamine 6G and the NIR laser dye styryl 11 (STaR 11) was coated onto an aluminium oxide nanopowder and then mixed with silver magnetic powder to develop and visualise fingermarks in the NIR. When compared to Blitz Green(?), it was determined that the STaR 11 magnetic powder was better suited for marks deposited on textured surfaces and for older marks, whereas Blitz Green(?) performed better on smooth glossy surfaces. The ability of the STaR 11 mixed dye formulation to be visualised in both the visible and NIR regions also provides a significant advantage over conventional luminescent fingermark powders.     

Identification of ascorbic acid and its degradation products in black powder substitutes

Low explosives such as smokeless powder, black powder, and black powder substitutes have been used in illicit pipe bombings throughout the United States. Some of the newer black powder substitutes are formulated with ascorbic acid, which gradually decomposes as the powder ages, making it difficult if not impossible for the forensic chemist to identify it by traditional bulk techniques. A sensitive method for the identification of residual levels of ascorbic acid in black powder substitutes is presented. Powder samples are extracted with a mixture of acetonitrile and bis(trimethylsilyl)acetamide (BSA), which converts carboxylic acid and alcohol functional groups to trimethylsilyl esters and ethers, respectively. Samples are then analyzed by gas chromatography-mass spectrometry (GC-MS). Results have shown that trace amounts of ascorbic acid can be identified at detection limits that are well below those for traditional bulk techniques. Degradation products for ascorbic acid (hydroxylated carboxylic acids, furanones, and lactones) can also be detected.     

Penetration Depth of Projectiles Fired from a Replica of Colt Navy of 1851 in 20% Gelatin Blocks Correlated with Fatal Injuries Assessed in an Autopsy of a 78‐Year‐Old Man

Pursuant to the Polish Weapons and Ammunitions Law, muzzle‐loading black powder weapons, manufactured before 1885, or their replicas, as well as suitable projectiles, can be possessed legally without registration and special licenses. The aim of the study was to assess the penetration depth of projectiles fired from a black powder weapon, replica of Colt Navy of 1851, in 20% gelatin blocks and to compare the obtained results with the actual injuries found on autopsy of a 78‐year‐old man who had committed suicide. In the experiments, we used the black powder weapon and ammunitions, as well as gelatin blocks serving as a soft tissue model. We ascertained that solid spherical projectiles fired from black powder weapons cause extensive injuries, especially in the initial segment of the wound canal. Additionally, based on the presence and location of the wad in the wound canal, the distance from which the shot was fired can be determined.     

A preliminary investigation into the acquisition of fingerprints on food

The potential for enhancement and recovery of latent fingerprints on a variety of foodstuffs has been investigated. In general, black magnetic powder and black powder suspensions appear to be the most successful enhancement techniques with a high number of ridge detail-developed prints over a selected time scale. Banana, apple and tomato surfaces showed enhancement of latent prints but potato and egg surfaces proved to be less successful.     

Gunshot wounds: visual and analytical procedures.

Visual examination of clothing and tissue from gunshot wounds provides information pertaining to the range of discharge of a firearm. Identification of powder grains or soot is evidence of close range discharge by a handgun. Analyses of tissue by EDX and FAAS technics are shown to supply corroborating data to visual examination in estimation of range. These methods are of particular value in differentiating contact and distant wounds when decomposed bodies are examined and when multiple layers of clothing are present.     

Enhancement of Aged and Denatured Fingerprints Using the Cyanoacrylate Fuming Technique Following Dusting with Amino Acid‐Containing Powders

We have carried out experiments to investigate the aging of latent fingerprints deposited on black PVC over a period of 4–15 weeks. A thumbprint was used in each case and before deposition of the print the donor rubbed their thumb around their nose to add sebaceous deposits. We have studied the effect of heat, light, and moisture and we find that moisture is the most significant factor in the degradation of the latent print. We have attempted to enhance these latent prints by dusting with valine powder or powders composed of valine mixed with gold or red fluorescent commercial fingerprint powders. To make a direct comparison between “treated” and “untreated” prints, the prints were cut in half with one‐half being “treated” and one‐half not. Our studies show the best results being obtained when powders of valine and red fluorescent powders are applied prior to cyanoacrylate fuming.     

8种方法显现的汗潜指印STR分型研究

目的研究常见指印显现方法对指印STR检验的影响。方法采用Invisorb spin forensic试剂盒提取纯化人汗潜指印DNA,低拷贝模板(LCN)STR复合扩增,荧光电泳检验。结果用铜粉、铝粉、荧光粉、黑磁粉、"502"胶、茚三酮、磺酸双三嗪荧光显色液显现的玻片、纸张和胶带纸粘面上的汗潜指印可成功进行STR分型。结论常见指印显现方法不影响指印STR检验。