Identification Method for Digital Image Forgery and Filtering Region through Interpolation

Because of the rapidly increasing use of digital composite images, recent studies have identified digital forgery and filtering regions. This research has shown that interpolation, which is used to edit digital images, is an effective way to analyze digital images for composite regions. Interpolation is widely used to adjust the size of the image of a composite target, making the composite image seem natural by rotating or deforming. As a result, many algorithms have been developed to identify composite regions by detecting a trace of interpolation. However, many limitations have been found in detection maps developed to identify composite regions. In this study, we analyze the pixel patterns of noninterpolation and interpolation regions. We propose a detection map algorithm to separate the two regions. To identify composite regions, we have developed an improved algorithm using minimum filer, Laplacian operation and maximum filters. Finally, filtering regions that used the interpolation operation are analyzed using the proposed algorithm.     

A Comparison of Solvent Extract Cleanup Procedures in the Analysis of Organic Explosives

The use of an organic solvent to extract explosive residues from hand swabs and postblast debris inevitably leads to the coextraction of unwanted materials, usually in far greater quantities than any explosive residue. In this study, the extraction efficiency of a number of solvent cleanup procedures including solid‐phase extraction (SPE), adsorbent resins such as Chromosorb‐104, and traditional materials such as silica and Florisil was calculated using a quantitative liquid chromatography–ultraviolet (LC‐UV) detection procedure. The Oasis^® HLB cartridge outperformed other cleanup procedures, with analyte recoveries approaching 95%, while the Amberlite XAD‐7 procedure returned the lowest overall recoveries. The matrix rejection ability of each method was then determined using a simulated highly contaminated matrix, with the adsorbent resins showing a higher degree of matrix rejection, which is seen as a reduction in background noise in the UV chromatogram using 210 nm detection.     

Comparison of the Volatile Organic Compounds from Different Biological Specimens for Profiling Potential*

Previous work has demonstrated the ability to differentiate individuals based on the analysis of human scent hand odor chemicals. In this paper, a range of forensic biological specimens are shown to also have the ability to differentiate individuals based upon the volatile organic compounds (VOCs) present. Human VOC profiles from hand odor, oral fluid, breath, blood, and urine of 31 individuals were analyzed by solid‐phase microextraction–gas chromatography–mass spectrometry (SPME‐GC‐MS) and combined methods of chromatogram comparison, Spearman rank correlation comparison, and principal component analysis. Intra‐specimen comparisons demonstrated the distinguishability of individuals above 99%. Inter‐specimen VOC profiles from the same individual were found to be too different to be used for scent‐matching purposes, with Spearman rank coefficients below 0.15. A 6‐month VOC profile monitoring of two individuals demonstrated the consistency of VOC profiles over time across specimens.     

Relationship between the Change Rules of Volatile Organic Compounds in Rat Muscle and Postmortem IntervalCSCD

Objective: To explore the relationship between the change rules of volatile organic compounds (VOCs) in rat muscle and postmortem interval (PMI). Methods: A total of 120 healthy rats were divided randomly into 12 groups (10 for each group). After the rats were sacrificed by cervical dislocation, the bodies were kept at (25±1) ℃ Rat muscle samples were separately obtained at 12 PMI points, including 0, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9 and 10 d. The VOCs in rat muscles were collected, detected and ana-lyzed by headspace solid-phase micro extraction (HS-SPME) coupled to gas chromatography-mass spec-trometer (GC-MS). Results: In total, 15 species of VOCs were identified, including 9 aromatic compounds, 3 sulfur compounds, 2 aliphatic acids and 1 heterocyclic compound. The species of VOCs increased with PMI: no species were detected within 1 day, 3 species were detected on day 2, 9 on day 3, 11 on day 4, 14 from day 5 to 7, and 15 from day 8 to 10. Total peak area of 15 species of VOCs was significantly correlated to PMI (adjusted R2=0.15-0.96): the regression function was y=-17.05 x2+164.36x-246.36 (adjusted R2=0.96) from day 2 to 5, and y=2.24x+101.13 (adjusted R2=0.97) from day 6 to 10. Conclusion: The change rules of VOCs in rat muscle are helpful for PMI estimation. © 2017 by the Editorial Department of Journal of Forensic Medicine.     

现场勘查指挥中存在的问题及其对策探析

现场勘查工作对刑事案件的侦破起着十分重要的作用,随着法制化进程的不断推进,对现场勘查各环节的规范化要求日益提高。当前各级公安机关都十分重视犯罪现场勘查仪器、设备的投入,然而硬件的完善只能为做好犯罪现场勘查工作提供技术支持,因此加强对犯罪现场勘查的环节控制,提出有针对性的解决对策就显得十分重要。     

LC/MS分析血浆中丁丙诺啡

目的建立血浆中丁丙诺啡液相色谱/质谱（LC/MS）分析方法。方法在含有丁丙诺啡的血浆中,加入内标奋乃静,加pH10.8缓冲溶液,用401有机担体作吸附剂、三氯甲烷作洗脱剂固相萃取,N2挥干,用50μL流动相定容后进行LC/MS分析。色谱条件：Thermo Hypersil-HyPURITY C18（150×2.1mm,5μm）,柱温：40℃,流动相：10mmol/LNH4AC（pH3.4）∶甲醇∶乙腈=36∶52∶12,流速：0.22mL/min。结果方法的线性范围为0.05～5.0μg/L（r=0.9998）,定量限0.05μg/L,检出限0.01μg/L（S/N=3）;3个浓度的质量控制样品（0.1μg/L,0.5μg/L,2.0μg/L）平均回收率分别为86.40%,92.72%,92.57%,RSD分别为4.51%,3.34%,2.09%。结论该方法操作简便、灵敏度高,可用于涉毒案件血浆中丁丙诺啡的分析。     

固相萃取-气相色谱法提取全血中的外源性褪黑素

目的建立血样中褪黑素的固相萃取方法。方法采用OasisHLB固相萃取柱提取,GC/NPD定量检验,GC/MS定性检验。结果血样中褪黑素平均萃取回收率达80%以上,最低检出限0.02μg/mL,线性良好,相关系数R2=0.9978。结论该方法操作简便快速,提取回收率高,重现性好,提取物干净,可用于实际案件当中。     

分子印迹固相萃取技术-液相色谱法测定鱼塘水中2甲4氯苯氧乙酸

目的建立分子印迹固相萃取技术对鱼塘水中2甲4氯苯氧乙酸进行提取和分析的方法。方法以2甲4氯分子印迹聚合物为固相萃取材料,对鱼塘水中2甲4氯进行分离提取,洗脱液直接进行液相色谱分析。结果鱼塘水中MCPA的提取率在80%以上,检出限0.040μg/mL,在0.2μg/mL～2.0μg/mL范围内线性关系良好。结论该方法的准确度和精密度较好,适合实际发生案件的检测分析。     

固相萃取技术（SPE）在苯丙胺类毒品分析中的应用

固相萃取（SPE）技术是利用固体吸附剂将目标化合物吸附,使之与样品的基体及干扰化合物分离,从而达到分离和富集的目的。SPE是20世纪70年代后期发展起来的一种样品前处理技术,本文主要综述了近10年来SPE技术在苯丙胺类毒品分析中的应用现状及其趋势。     

街面侵财型犯罪的社会化预防

现阶段,街面侵财型犯罪日益突出,已经严重危害到人民群众的财产和人身安全。在治理街面侵财型犯罪的过程中,对其实行社会化预防,是一种超前的治理手段,具有从本质上消除犯罪的意义。街面侵财型犯罪的社会化预防可以按照犯罪学的理论,依照犯罪预测、抑制犯罪动机、限制犯罪机会和条件、预防重新犯罪等分步实行。