纹线中空特征在指纹比对中的应用

目的探讨纹线中空特征应用于某些残缺、特征数量不足的指纹检验中的可行性。方法引入指纹三级特征理论,从该特征的存在机理、稳定性特点及与其它类似特征的区别等进行观察。结果纹线中空特征稳定存在,且在比对工作中具有可操作性。结论纹线中空特征是对常规特征的补充,对指纹比对工作具有实际意义。     

探析高分辨率指纹特定条件下三级特征的稳定性

目的探索油墨捺印指纹显现三级特征稳定性的影响因素,排除主观条件的影响。方法在最适宜的条件下,通过油墨捺印采集不同压力下的指纹样本,清晰地显出指纹三级特征,用高分辨率扫描仪扫描试验样本,保存指纹样本,最后分析了指纹汗孔、细点线、纹线形态、皱纹等三级特征的反映性及稳定性,确定其鉴定价值。结果油墨捺印法对三级特征的反映性不够理想,汗孔、纹线形态特征、细点线特征及皱纹在不同压力下的稳定性较差。其中,各个三级特征在轻压下的反映性及稳定性较为接近实际,捺印的压力越大则三级特征变形越大,甚至完全变形成为另外一种特征。结论所以如果将此法应用于指纹比对时,仍需进一步的研究与改进。     

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。     

Can the RUVIS Reflected UV Imaging System Visualize Fingerprint Corrosion on Brass Cartridge Casings Postfiring?

Comparisons are made between the visualization of fingerprint corrosion ridge detail on fired brass cartridge casings, where fingerprint sweat was deposited prefiring, using both ultraviolet (UV) and visible (natural daylight) light sources. A reflected ultraviolet imaging system (RUVIS), normally used for visualizing latent fingerprint sweat deposits, is compared with optical interference and digital color mapping of visible light, the latter using apparatus constructed to easily enable selection of the optimum viewing angle. Results show that reflected UV, with a monochromatic UV source of 254 nm, was unable to visualize fingerprint ridge detail on any of 12 casings analyzed, whereas optical interference and digital color mapping using natural daylight yielded ridge detail on three casings. Reasons for the lack of success with RUVIS are discussed in terms of the variation in thickness of the thin film of metal oxide corrosion and absorption wavelengths for the corrosion products of brass.     

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.     

Thermal degradation analysis of amino acids in fingerprint residue by pyrolysis GC-MS to develop new latent fingerprint developing reagents

Conventional development of latent fingerprints is compromised when the prints are decomposed by extreme temperatures, such as those encountered when a weapon cartridge is fired, an improvised explosive device is detonated, and/or in arson cases. Understanding how these extreme temperatures alter the chemical and physical properties of latent fingerprint residue could aid in the discovery of a reagent that could effectively develop these decomposed fingerprints. To mimic scenarios where fingerprints may be exposed to high heat conditions, standards of the five most abundant amino acids in fingerprint residue as well as extracted fingerprint residue were pyrolized under controlled conditions. Compounds identified as pyrolytic decomposition products were 3,6-dimethylpiperazine-2,5-dione (from alanine), maleimide, and 2,5-furandione (from aspartic acid). The pyrograms and selected ion traces show these products to hold promise as indicators of decomposed fingerprint residues and, therefore, may serve as good candidate substrates for a developing reagent.     

Integrated DNA and Fingerprint Analyses in the Identification of 60‐Year‐Old Mummified Human Remains Discovered in an Alaskan Glacier

Abstract: This report describes the identification of a merchant mariner who perished in 1948 when Northwest Airlines Flight 4422, a DC‐4 carrying 24 seamen and six crew members crashed into Mount Sanford, Alaska. Fifty‐one years later, a human forearm and hand were found close by the wreckage of the plane, prompting identification efforts using DNA and fingerprints. There were significant challenges to both the fingerprint and DNA analyses. The hand was badly desiccated, making fingerprint friction‐ridge detail almost invisible and the remains had been embalmed upon discovery, making DNA amplification difficult. We present the results of an interdisciplinary approach that successfully addressed these challenges and ultimately led to the identification of the remains. These efforts relied on efficient fingerprint rejuvenation and imaging techniques that improved print resolution, as well as new DNA extraction techniques optimized for aggressively embalmed remains.     

紫外激光技术显现潜在指印的研究

目的研究显现潜在指印的新技术。方法用自主研发的266nm短波紫外线输出的ND：YAG激光器作为激发光源激发渗透性客体表面的潜在指印,使指印发出荧光。结果能有效显现出亮纹线暗背景的潜在指印发光图像。结论利用该紫外激光技术可以显现纸张等渗透性客体表面的潜在指印。     

紫外光谱成像技术显现潜在油汗混合指印的初步探索

目的研究运用紫外光谱成像技术显现潜在油汗混合指印的可行性和方法。方法使用紫外光谱成像仪获取典型潜在油汗混合指印的光谱影像数据资料,比较不同数据处理软件的分析结果。结果紫外光谱成像技术具有显现潜在油汗指印的能力。结论紫外光谱成像技术能够成功显现非渗透性客体表面潜在油汗混合指印。     

Fluorescence of 1,2‐Indanedione with Amino Acids Present in the Fingerprint Residue: Application in Gender Determination

1,2‐indanedione is used for latent fingerprint visualization on porous surfaces. In this paper, fluorescence spectra of 1,2‐indanedione after reacting with 21 individual amino acids present in latent fingerprints residue were measured in water‐methanol solutions. The fluorescence intensity depends on the amino acid used, while the fluorescence peak does not change much. The concentration of amino acids in fingerprint residue in females is almost the double of their concentration in males. This property combined with fluorescence of 1,2‐indanedione‐amino acids compounds is used for gender determination, by comparing the fluorescence intensity peaks in the same experimental conditions. In this preliminary study, the fluorescence signal from the samples representing females was almost two times the signal for samples representing males. In addition to the reduction by almost 50% of the number of suspects in a criminal research case, these results could be helpful in gaining some knowledge about the papillary residue composition.