Optical enhancement of fingerprint deposits on brass using digital color mapping

Abstract: The reflection of visible light from α‐phase brass subject to surface oxidation in air at elevated temperatures is investigated. X‐ray photoelectron and auger electron spectroscopy confirm that covered areas of brass (not exposed to air) display dezincification but an absence of significant surface oxidation, confirming a differential oxidation mechanism. Visualization of differential oxidation is shown to be enhanced by selective digital mapping of colors reflected from the surface of the brass using Adobe^® Photoshop^®. Enhancement is optimal when the brass is heated to ～250°C with areas of oxidation having a mirror‐like appearance. The use of this enhancement method to produce a faithful image of fingerprint ridge characteristics is demonstrated on brass shell casings where fingerprints were deposited prefiring.     

The regulation of cognitive enhancement devices: extending the medical model

This article presents a model for regulating cognitive enhancement devices (CEDs). Recently, it has become very easy for individuals to purchase devices which directly modulate brain function. For example, transcranial direct current stimulators are increasingly being produced and marketed online as devices for cognitive enhancement. Despite posing risks in a similar way to medical devices, devices that do not make any therapeutic claims do not have to meet anything more than basic product safety standards. We present the case for extending existing medical device legislation to cover CEDs. Medical devices and CEDs operate by the same or similar mechanisms and pose the same or similar risks. This fact coupled with the arbitrariness of the line between treatment and enhancement count in favour of regulating these devices in the same way. In arguing for this regulatory model, the paper highlights potential challenges to its implementation, and suggests solutions.     

图像降噪和增强对人脸识别系统识别性能的影响

目的研究图像降噪和图像增强方法对人脸识别系统识别性能的影响,以期为人脸识别系统应用过程中的图像处理方法选取提供理论指导和技术方案。方法收集33起人像鉴定领域实际案例中的人脸图像素材,研究以高斯滤波和小波变换为代表的图像降噪技术以及具有边缘保持和小波变换特性的单帧图像超分辨率增强技术对人脸识别系统识别性能的影响,并对不同图像处理方法对人脸识别性能的影响进行量化比较分析。结果本文研究的图像降噪技术均显著提高了人脸识别系统的识别准确性,而图像增强技术虽然提高了人脸图像显示效果,但对人脸识别系统的识别性能无正向促进作用。此外,高斯模糊图像处理的图像降噪方法虽然简单,但与本文研究的其他方法比较,其在人脸识别系统识别性能改善方面效果最显著。结论人脸图像质量对人脸识别系统的识别性能具有显著影响,可以通过图像处理技术改善人脸图像质量进而提高人脸识别系统的识别准确性。其中,图像降噪处理可以显著提高人脸识别系统的识别性能,且比图像增强技术更适合于实际人像鉴定应用中的人脸识别系统识别性能增强。     

Practical benzylation of N,N-substituted ethanolamines related to chemical warfare agents for analysis and detection by electron ionization gas chromatography–mass spectrometry

The benzylation of three low molecular weight N,N-disubstituted ethanolamines related to chemical warfare agents (CWAs) to furnish derivatives with improved gas chromatography-mass spectrometry (GC-MS) profiles is described. Due to their low molecular weight and polar nature, N,N-disubstituted ethanolamines are notoriously difficult to detect by routine GC-MS analyses during Organisation for the Prohibition of Chemical Weapons (OPCW) proficiency tests (PTs), particularly in scenarios when they are present at low levels (~1–10 ppm) amidst more abundant interferences. Our studies revealed that the optimal derivatization conditions involved the treatment of the ethanolamine with benzyl bromide in the presence of an inorganic base (e.g., Na₂CO₃) in dichloromethane at 55°C for 2 h. This optimized set of conditions was then successfully applied to the derivatization of N,N-dimethylethanolamine, N,N-diethylethanolamine and N,N-diisopropylethanolamine present separately at 1 and 10 μg/mL concentrations in a glycerol-rich matrix sample featured in the 48th OPCW PT. The benzylated derivatives of the three ethanolamines possessed retention times long enough to clear the massive glycerol-containing matrix interferences. The protocol herein is introduced as an alternative method for derivatization of these CWA and pharmaceutically important species and should find broad applicability in laboratories where routine forensic analysis is carried out.     

关于我国开展资产证券化几个法律问题的探讨

在资产证券化比较发达的国家,围绕资产证券化已建立起较为完备的配套法律制度,甚至,有的国家对资产证券化进行了专门的立法.当前,资产证券化在我国还是新鲜事物,围绕其在中国的开展及发展有众多的相关法律问题需要解决.     

Synthesis and Analysis of Glucuronic Acid‐Conjugated Metabolites of 4‐Bromo‐2,5‐Dimethoxyphenethylamine

In the study reported here, two glucuronic acid‐conjugated metabolites of 4‐bromo‐2,5‐dimethoxyphenethylamine (2C‐B)—a ring‐substituted psychoactive phenethylamine—were chemically synthesized for the first time and a method for analyzing them in urine was developed. β‐D‐Glucuronide of 4‐bromo‐2,5‐dimethoxyphenylethylalcohol was successfully synthesized using methyl 2,3,4‐tri‐Ο‐acetyl‐1‐O‐(trichloroacetimidoyl)‐α‐D‐glucuronate as a glucuronyl donor and boron trifluoride diethylether complex as a Lewis acid catalyst. β‐D‐Glucuronide of 4‐bromo‐2,5‐dimethoxyphenylacetic acid was synthesized by condensing 4‐bromo‐2,5‐dimethoxyphenylacetic acid and benzyl D‐glucuronate followed by benzyl group deprotection based on catalytic hydrogenation. Two glucuronic acid‐conjugated metabolites of 2C‐B in urine were qualitatively and semiquantitatively evaluated via direct liquid chromatography/mass spectrometry (LC/MS) analysis of a diluted urine sample. The simple method proposed is expected to be useful for studying the metabolic fate of 2C‐B.     

我国应对日本“肯定列表制度”的措施

日本“肯定列表制度”的实施,对我国农产品出口日本造成了重大影响,我国政府和企业对此应认真研究,积极采取措施,完善相关限量检测标准体系和产品质量相关法律法规,并加强科技研发,提高我国农产品质量,增强市场竞争力,逐步恢复和增加农产品对日出口量。     

Isolation and Identification of Three By‐products Found in Methylamphetamine Synthesized by the Emde Route

This article describes the isolation and structural elucidation of three compounds produced during the synthesis of methylamphetamine by the so‐called “Emde” procedure. The “Emde” procedure involves the preparation of the intermediate chloropseudoephedrine or chloroephedrine from ephedrine or pseudoephedrine, respectively. The intermediates are then reduced to methylamphetamine with hydrogen under pressure in the presence of a catalyst. The by‐product compounds were isolated from methylamphetamine by column chromatography and liquid chromatography (LC). Proton nuclear magnetic resonance spectroscopy (¹H NMR), carbon nuclear magnetic resonance spectroscopy (¹³C NMR), and nanospray quadrupole‐time of flight‐mass spectrometry (Q‐TOF‐MS) were used to identify them as two stereoisomers of the compound N, N′‐dimethyl‐3,4‐diphenylhexane‐2,5‐diamine and N‐methyl‐1‐{4‐[2‐(methylamino)propyl]phenyl}‐1‐phenylpropan‐2‐amine.     

杀虫剂麦巨丰的检验方法

介绍了合成杀虫剂麦巨丰的检验方法,特点是简便、快速、准确,具有实用性.     

Can latent fingerprint disclose the sex of the donor? A preliminary test study using GC–MS analysis of latent fingerprints

While fingerprints are a highly used means of identification, not every fingerprint left behind on a potential crime scene can be used for identification purposes. In some cases, the fingerprint may be smudged, partially preserved or overlapping with other prints hence distorting the ridge pattern and may therefore be not appropriate for identification. Further, fingermark residue yields a very low abundance of genetic material for DNA analysis. In such cases, the fingermark may be used to retrieve basic donor information such as sex. The focus of this paper was to assess the possibility of differentiating between the sexes of the donor of latent fingermarks. Analytical method was GC–MS analysis of the chemical compounds of latent fingermarks using 22 male and 22 female donors. Results showed 44 identified compounds. Two alcohols, octadecanol C₁₈ and eicosanol C₂₀, were found to show a difference that was statistically significant between male and female donors. There is also some evidence for the possibility of distinguishing sex of the fingermark donor based on the distribution of branched chain fatty acids, as free compounds or esterified in wax esters.