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排序方式: 共有223条查询结果,搜索用时 15 毫秒
81.
A case is reported involving a U.S. Treasury check with an altered amount payable. The ink in the alteration and the ink in the endorsement signature were compared with ink from three Skilcraft ball pens all having Skilcraft black ink ball pen refills. Infrared luminescence photography of their thin-layer chromatograms revealed differences between the inks in the three pens. 相似文献
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Evaluation of Four Fingerprint Development Methods for Touch Chemistry Using Matrix‐Assisted Laser Desorption Ionization/Time‐of‐Flight Mass Spectrometry,
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Kimberly A. Kaplan‐Sandquist Ph.D. Marc A. LeBeau Ph.D. Mark L. Miller Ph.D. 《Journal of forensic sciences》2015,60(3):611-618
Four preparation techniques for MALDI/TOF mass spectrometry were compared to determine the ability to gather intelligence for investigations through the chemical analysis of latent fingerprints, defined as “touch chemistry.” Compatible fingerprint development processes used for identification along with new techniques are necessary to evaluate touch chemistry. Ten volunteers deposited fingerprints from solvent residues containing drugs and explosives onto microscope slides. The developers included (A) fingerprint powder, (B) MALDI matrix, (C) fingerprint powder and lifting, and (D) cyanoacrylate fuming with fingerprint powder. Qualitative identification was based on ion images and spectra. The highest average detection rates (88%) were found using methods A and B. Methods C (52%) or D (18%) had limited success. Results demonstrate the importance of imaging coupled to extracted mass spectral data in detecting analytes in deposited fingerprints. Overall, the results suggest continued development of touch chemistry applications could prove useful for gathering intelligence and forensically relevant information. 相似文献
84.
外墙外保温技术推广应用需要相关政策法规的支持。建议:首先加大政策法规的整合力度,在纵向上考虑不同层面法律法规的一致性,在横向上充分考虑政策、法规和技术标准之间的配套和衔接。其次,要针对外墙外保温技术复杂、涉及面广、职能交叉的特点,提高政策法规的针对性和可操作性。第三,要加强行政监督和执法力度。 相似文献
85.
Hidetoshi Kakuda PhD Norimitsu Akiba PhD Kazuhito Hibino BS Ken’ichi Tsuchiya PhD Kosuke Tanabe PhD Kazunari Shibasaki MS 《Journal of forensic sciences》2024,69(2):669-677
Latent fingerprints were successfully visualized using fluorescence lifetime imaging (FLIM) on paper which emits strong fluorescence with a lifetime close to that of fingerprints and thus from which it is difficult for time-resolved spectroscopy to visualize fingerprints. Latent fingerprint samples on paper were excited using a 450 nm or 532 nm nanosecond pulsed-laser, and time-resolved fluorescence images were obtained at a delay time of 6–16 ns in intervals of 1 ns, to the excitation pulse. The excitation beam was expanded using a lens, and the fluorescence from the fingerprints was captured using an intensified CCD camera. Because of the large fluorescence intensity of the background paper of approximately two to four orders of magnitude larger than that of the fingerprint, the fingerprint was not visualized on each fluorescence image by time-resolved spectroscopy. However, the fingerprint was visualized in a FLIM image constructed using a series of the fluorescence images for the case with the fluorescence intensity of the background paper being four orders of magnitude larger than that of the fingerprint. The difference in fluorescence lifetime in the FLIM image of the visualized fingerprint and background paper was in the order of 0.1 ns, which was an order of magnitude smaller than the inherent fluorescence lifetime of a few nanoseconds for the fingerprints and paper. It was demonstrated that, at a background fluorescence intensity with a certain order of magnitude larger than that of fingerprints, FLIM has the potential to visualize latent fingerprints which cannot be visualized by time-resolved spectroscopy. 相似文献
86.
Gerda J. Edelman M.Sc. Richelle J.M. Hoveling M.Sc. Martin Roos Ton G. van Leeuwen Ph.D. Maurice C.G. Aalders Ph.D. 《Journal of forensic sciences》2013,58(5):1156-1162
All objects radiate infrared energy invisible to the human eye, which can be imaged by infrared cameras, visualizing differences in temperature and/or emissivity of objects. Infrared imaging is an emerging technique for forensic investigators. The rapid, nondestructive, and noncontact features of infrared imaging indicate its suitability for many forensic applications, ranging from the estimation of time of death to the detection of blood stains on dark backgrounds. This paper provides an overview of the principles and instrumentation involved in infrared imaging. Difficulties concerning the image interpretation due to different radiation sources and different emissivity values within a scene are addressed. Finally, reported forensic applications are reviewed and supported by practical illustrations. When introduced in forensic casework, infrared imaging can help investigators to detect, to visualize, and to identify useful evidence nondestructively. 相似文献
87.
Apparatus to produce a spatially and temporally uniform heat source is described and this is used to visualize latent fingerprints deposited onto thermal paper by raising the temperature of the paper. Results show an improvement over previous research when fingerprint deposits are aged or the developed fingerprints faint; visualization being enhanced by the use of a blue LED light source of 465 nm peak wavelength. An investigation of the components in fingerprint sweat likely to affect the solubility and hence color change of the dye present in the thermal paper has shown that polar protic solvents able to donate a proton are favored and a polar amino acid found commonly in eccrine fingerprint sweat (lysine) has been shown able to produce the desired color change. Aged fingerprint deposits on thermal paper from a variety of sources up to 4 years old have been visualized with this technique. 相似文献
88.
A new method for enhancement of ninhydrin or 1,8-diazafluoren-9-one (DFO)-treated latent fingerprints on thermal paper will be described. Most thermosensitive surfaces of thermal paper become dark when treated with DFO or ninhydrin petroleum ether (NPB) solution. This effect minimizes contrast between the developed fingerprints and the background. The new method described reduces this dark staining without removing the thermosensitive layer and parts of the developed fingerprints, as occurs with acetone washing. Through the new method, the developed fingerprints appear in sharp lines and high contrast. Extensive tests were performed, leading to an optimized working solution, which charges the paper with a minimum of chemicals, is cheap, and enables a large quantity of papers to be treated in a short time. The working solution contains commercially available, nonvolatile, nitrogenous organic compounds and can be used like the application of NPB solution by dipping. 相似文献
89.
Yen K Lövblad KO Scheurer E Ozdoba C Thali MJ Aghayev E Jackowski C Anon J Frickey N Zwygart K Weis J Dirnhofer R 《Forensic science international》2007,173(1):21-35
Multislice-computed tomography (MSCT) and magnetic resonance imaging (MRI) are increasingly used for forensic purposes. Based on broad experience in clinical neuroimaging, post-mortem MSCT and MRI were performed in 57 forensic cases with the goal to evaluate the radiological methods concerning their usability for forensic head and brain examination. An experienced clinical radiologist evaluated the imaging data. The results were compared to the autopsy findings that served as the gold standard with regard to common forensic neurotrauma findings such as skull fractures, soft tissue lesions of the scalp, various forms of intracranial hemorrhage or signs of increased brain pressure. The sensitivity of the imaging methods ranged from 100% (e.g., heat-induced alterations, intracranial gas) to zero (e.g., mediobasal impression marks as a sign of increased brain pressure, plaques jaunes). The agreement between MRI and CT was 69%. The radiological methods prevalently failed in the detection of lesions smaller than 3mm of size, whereas they were generally satisfactory concerning the evaluation of intracranial hemorrhage. Due to its advanced 2D and 3D post-processing possibilities, CT in particular possessed certain advantages in comparison with autopsy with regard to forensic reconstruction. MRI showed forensically relevant findings not seen during autopsy in several cases. The partly limited sensitivity of imaging that was observed in this retrospective study was based on several factors: besides general technical limitations it became apparent that clinical radiologists require a sound basic forensic background in order to detect specific signs. Focused teaching sessions will be essential to improve the outcome in future examinations. On the other hand, the autopsy protocols should be further standardized to allow an exact comparison of imaging and autopsy data. In consideration of these facts, MRI and CT have the power to play an important role in future forensic neuropathological examination. 相似文献
90.