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在犯罪现场发现的各类痕迹中,手印是少数可以直接对嫌疑人身份进行认定,并可作为法庭科学证据的痕迹类型之一。然而,犯罪现场的手印往往是肉眼不可见的,即潜在手印。为实现潜在手印的可视化,各类手印的提取及显现技术应运而生。其中,膜转移提取技术结合物理、化学等方法将手印转移到膜材料上进行快速显现,乃至进一步分析。本文系统地介绍了膜转移提取技术在手印显现中的研究进展,并对该技术的发展方向提出了展望。 相似文献
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以柠檬酸和尿素为反应原料、乙二醇为反应溶剂,采用溶剂热法合成了荧光碳点(Carbon dots,CDs),并对CDs的形貌、粒径、晶体结构、元素成分、表面基团和光学性质等进行了表征。研究了CDs对激发光依赖的荧光发射特性,讨论了反应温度、反应时间和原料比例等合成条件对CDs的激发波长和发射波长的影响。将CDs与淀粉、纳米二氧化硅、蒙脱土、高岭土、硅藻土和氧化镁6种基质复合,制备出一系列CDs荧光复合物。最终将CDs-淀粉荧光复合物应用于光滑客体表面潜在手印的增强显现,并从定性和定量两个层面对显现效果进行了详细评价。利用CDs-淀粉荧光复合物对激发光依赖的荧光发射特性,结合滤光拍照,在很大程度上降低了客体背景噪声干扰。手印显现结果表明,显现信号与客体背景噪声之间的对比反差明显,具有较强的显现对比度;显现手印的各级特征反映清晰,具有较高的显现灵敏度;显现粉末与手印遗留物质之间的结合程度较高,具有较好的显现选择性。 相似文献
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遗留在犯罪现场的肉眼不可见的潜在手印是一类重要的痕迹物证,检验鉴定前需要使用一定技术手段将其显现出来。近年来,一些新材料和新技术的引入为手印显现技术的革新注入了新活力,其中稀土发光材料、量子点、荧光金属纳米簇等发光材料在该领域展现出极大潜力。碳点作为具有良好光致发光性能的新型纳米材料,近来逐渐引起了手印显现领域研究人员的广泛关注。本文综述了两类基于碳点材料的手印显现技术国内外研究进展,分别是液体分散碳点用于手印显现和固态发光碳点用于手印显现。具体来说,液体分散碳点显现手印的原理主要基于传统小微粒悬浮液机理或一些特殊效应(咖啡环效应、界面偏析效应);用于手印显现的固态发光碳点包括固态碳点粉末和固态碳点复合粉末两类,合成这些材料时研究人员采用了不同的策略。最后,从三个方面分析了碳点在手印显现应用中面临的问题,即碳点物理形貌和表面性质、碳点光致发光性质以及碳点显现过程与化学生物分析兼容性,并就解决问题的可能途径提出了展望。 相似文献
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以绿色荧光染料为原料,依次通过硅烷化修饰、胺基化修饰、羧基化修饰等步骤制备出表面活化羧基修饰的绿色荧光染料。利用绿色荧光染料表面的活化羧基与潜血手印及蛋白手印中的胺基在温和条件下发生酰胺反应,实现了潜血手印及蛋白手印的高质量与高效率显现。优化了手印显现的最佳条件,并对手印显现的对比度、灵敏度、选择性、适用性进行考察。实验结果表明,手印乳突纹线产生了明亮的绿色荧光,与客体背景之间形成了足够的对比反差,具有较高的对比度;乳突纹线连贯,细节特征明显,汗孔特征清晰,具有较高的灵敏度;乳突纹线与小犁沟之间差异明显,具有较高的选择性;本方法适用于显现光滑非渗透性及半渗透性客体表面潜血手印及蛋白手印,具有较强的适用性。 相似文献
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氰基丙烯酸酯20世纪70年代被引入法庭科学领域,成为显现非渗透性和半渗透性客体上潜在手印的高效方法。通过介绍氰基丙烯酸酯胶黏剂的发现与应用历史、聚合机理与手印显现原理、显出手印的增强方法,丰富了化学教育中关于聚合物、有机染料、荧光现象等方面的教学内容。 相似文献
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利用硅藻土对荧光染料的吸附作用,制备多种荧光染料-硅藻土复合物。利用荧光分光光度计分析复合物的荧光性质,根据不同复合物的荧光特性,选用相应的激发光源和滤光片,显现不同客体表面的潜在手印。通过将法庭科学前沿融入化学实验教学,使学生充分认识荧光现象在手印显现中的作用原理,能够使学生拓展科学思维,锻炼实验技能,提升创新意识。 相似文献
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纳米CdS/PAMAM G5.0显现胶带粘面油潜指纹应用 总被引:4,自引:0,他引:4
利用傅立叶红外光谱检测了聚酰胺-胺(PAMAM)G5.0显现液与油酸反应机理,以相对峰高比来观察不同反应条件下的反应情况,确定在120 ℃下反应2~3 h较好。以这种复合纳米材料为显现液,对犯罪现场3种常见胶带粘面上的油潜指纹进行显现,透明胶带上油潜指纹在420 nm下拍照,黑色电工胶带上油潜指纹在365 nm下拍照可得到很好的图像效果。将该显现材料的显现效果与现在常用罗丹明6G显现液的显现效果进行横向比较,以考察CdS/PAMAM G5.0在显现胶带粘面上油潜指纹方面起到的作用。CdS/PAMAM G5.0显现法同现有方法相比,对于常见胶带粘面上的油潜指纹具有理想的显现效果,其荧光强度、选择性吸附性能非常优异;长时间浸显后背景吸附小,与指纹纹线的反差大;指纹纹线流畅,显现细节特征能力强,其中对陈旧油潜指纹也有比较理想的显现效果;可以通过室光反射和紫外可见荧光两种形式成像,适用范围更广。一系列实验证明,CdS/PAMAM G5.0可以有效显出常见胶带粘面上的油潜指纹。 相似文献
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Enzymes have been widely used as efficient, eco‐friendly, and biodegradable catalysts in organic chemistry due to their mild reaction conditions and high selectivity and efficiency. In recent years, the catalytic promiscuity of many enzymes in unnatural reactions has been revealed and studied by chemists and biochemists, which has expanded the application potential of enzymes. To enhance the selectivity and activity of enzymes in their natural or promiscuous reactions, many methods have been recommended, such as protein engineering, process engineering, and media engineering. Among them, the additive approach is very attractive because of its simplicity to use and high efficiency. In this paper, we will review the recent developments about the applications of additives to improve the catalytic performances of enzymes in their natural and promiscuous reactions. These additives include water, organic bases, water mimics, cosolvents, crown ethers, salts, surfactants, and some particular molecular additives. 相似文献
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Reversible Response of Luminescent Terbium(III)–Nanocellulose Hydrogels to Anions for Latent Fingerprint Detection and Encryption 下载免费PDF全文
Jun Hai Tianrong Li Junxia Su Prof. Weisheng Liu Yanmin Ju Prof. Baodui Wang Prof. Yanglong Hou 《Angewandte Chemie (International ed. in English)》2018,57(23):6786-6790
Fingerprint fluorescence imaging has become one of the most prominent technologies in the field of forensic medicine, but it seldom considers the security protection of detection information, which is of great importance in modern society. Herein we demonstrate that luminescent TbIII–carboxymethyl cellulose (CMC) complex binding aptamer hydrogels that are reversibly responsive to ClO?/SCN? can be used for the selective detection, protection, and storage of fingerprint information. The imaging information of the fingerprint can be quenched and recovered by ClO?/SCN? regulation, respectively, resulting in reversible on/off conversion of the luminescence signals for the encryption and decryption of multiple levels of information. The present study opens new avenues for multilevel imaging, data recording, and security protection of fingerprint information with tunable fluorescent hydrogels. 相似文献
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R. Fouad 《应用有机金属化学》2020,34(4):e5497
The development of biocompatible fluorescent materials based on CdII (d10) systems for cytotoxic application and latent fingerprint detection under UV illumination has not yet been studied that thoroughly. In this sense, this work presents production of novel and dual nature pure Cd (II) phosphor complex based on ρ-dimethylaminobenzaldehyde thiosemicarbazone ligand (H-DMABTS). The structural characterization confirms that the ligand which acts as monoanionic bidentate through NS donor sites, forming mononuclear complex formulates as: [Cd (DMABTS)2(C2H5OH)2] where, DMABTS = anionic form of ρ-dimethylaminobenzaldehyde thiosemicarbazone. TEM analysis shows that Cd (II) complex has sheet like shape in micro scale. Moreover, the Cd (II) complex was dispersed into silica host. Photoluminescence emission and lifetime of H-DMABTS ligand, Cd (II) complex and Cd (II) complex dispersied into silica were measured. Cd (II) complex is intensive luminescent with impressive visual emission under UV excitation. All fluorescent materials were tested for their in vitro cytotoxicity against HepG-2 cell line. The Cd (II) phosphor complex shows higher activity (IC50 = 0.005 μM) than other prepared materials and different standard antitumor drugs. Furthermore, the Cd (II) phosphor complex has a lower toxicity value (LD50 = 130 mg/Kg) relative to the standard cis-platin (LD50 = 13.5 mg/Kg). Moreover, latent prints details, including their characteristic three levels, have been clearly identified from various forensic substrates (non-porous, semi-porous, porous) using Cd (II) phosphor complex. 相似文献