Synthesis of D-A typed AIE luminogens in isomeric architecture and their application in latent fingerprints imaging

Among the emitters in powder dusting to visualize the latent fingerprints(LFPs),aggregation-induced emission luminogens(AIEgens)are well employed for their high brightness and resistance to photobleaching.However,the serious background interference and low resolution still limit their fast development.Therefore,to further enhance the signal-to-noise ratio in LFPs imaging,especially to improve the analysis for level 3 details,donor-acceptor(D-A)typed AIEgens of DTPA-2,3-P,DTPA-2,5-P and DTPA-2,6-P are designed here.It is observed that strong emission covering from 450nm to 650nm can be obtained for all these molecules,especially that a high PLQY value of 10.06%in solids is achieved in DTPA-2,3-P.This is much higher than that of the other two cases(0.80%and 0.51%).By utilizing the DTPA-2,3-P in powder dusting,fluorescence imaging of LFPs can be clearly captured on both smooth and rough substrates.Moreover,confocal laser scanning microscope(CLSM)enables us to achieve high-resolution LFPs imaging in both 2D and 3D views,providing more detailed information of fingerprints pores in width,distance,distribution,and shapes.The results here demonstrate that highly emissive AIEgen of DTPA-2,3-P could be an excellent candidate for the visualization of fingerprints,thus providing the potential application in criminal investigation in the future.

One pot synthesis of TiO_2:Eu^(3+) hierarchical structures as a highly specific luminescent sensing probe for the visualization of latent fingerprints

In the present work, TiO2:Eu^(3+) (1 mol%e11 mol%) nano powders(NPs) were prepared via a facile one-pot hydrothermal method by using Epigallocatechin Gallate(EGCG) as bio-surfactant. The optimized TiO2:Eu^(3+) (5 mol%) NPs can be used as fluorescent labeling agent for visualizing of latent fingerprints(LFPs) on various porous and non-porous surfaces. The obtained results exhibit well defined ridge details with high sensitivity, selectivity, and low background hindrance which show greater advantages as compared to conventional powders. We demonstrated the viability of high-performance security labels thorough excellent luminescence for practical anti-mimetic applications. Morphology of the prepared samples is highly dependent on pH, concentration of the bio-surfactant, temperature and time durations.Photoluminescence(PL) emission spectra exhibit intense red emission at ~ 615 nm due to electric dipole transition(~5 D_0/~7 F_2). Photometric(CIE and CCT) results clearly show the intense warm red emission of the optimized samples. Therefore, this work offers a superior and universal luminescent label, which can be applied to visualize miniature LFPs particulars for individualization and consequently display great prospective in forensic investigation.

碳点在潜在指纹显影中的应用进展

碳点(CDs)是一种尺寸在10 nm以下的新型纳米材料,由于其独特的发光性能、低毒和环保等特点,在潜指纹检测中展现出了巨大的应用潜力。在潜指纹检测中,碳点的荧光特性可以帮助提高潜指纹的成像和识别能力。本文综述了碳点的合成方法、发光机理及其在潜指纹检测中的应用。通过合成方法优选、元素掺杂、前驱体调控、表面改性等手段可以调控碳点的荧光发射波长;再将碳点纳米粒子均匀分散在天然或常规材料上,所获得的碳点纳米复合材料可以避免因碳点纳米粒子聚集而引发的荧光淬灭现象,保留碳点的荧光性能,并且更适用于潜在指纹显现的常规操作。本文展望了在潜在指纹显影研究中碳点的未来发展方向,通过不断的改进和创新,期许为刑事科学技术领域的研究工作提供重要参考。

荧光碳点复合材料显现潜手印综合实验设计

为了提高学生的证据意识和综合科研能力,设计了一个涵盖碳点复合材料合成、结构表征和潜手印显现应用的综合性实验。以柠檬酸、三乙烯四胺和罗丹明6G为原料合成荧光碳点材料,通过自组装策略将碳点纳米颗粒原位嵌入金属有机骨架中,从而获得固态下具有强荧光发射的碳点复合材料。利用扫描电子显微镜、荧光光谱仪、粉末X射线衍射仪等分析仪器对复合材料进行表征。采用粉末刷显法将制备的复合材料用于不同客体表面的潜手印显现中,对显现效果进行了分析和评价。教学内容紧密联系学术前沿和实际应用,有助于提高学生分析问题、解决问题的能力,培养创新的科研精神。

Advances in the development and component recognition of latent fingerprints

Fingerprints have been used as an indispensable tool for personal identification in forensic investigations since the late 19 th century. At present, fingerprinting technology has moved away from its forensic roots and is incorporating a broader scientific range, e.g., material science, spectroscopy and spectral analysis, and even in vitro diagnosis. After a brief introduction to latent fingerprints, this mini-review presents the pioneering progresses of fingerprinting technologies including(i) material and electrochemical techniques, and(ii) spectral and spectroscopy imaging techniques and immunological techniques capable of both the visualization of a fingerprint and the detection of chemicals present in it. Finally, perspectives on this rapidly developing field are discussed.

Blue light-induced rare-earth free phosphors for the highly sensitive and selective imaging of latent fingerprints based on enhanced hydrophobic interaction

The demand for in-situ detection of latent fingerprints(LFPs)in ways of high sensitivity,high selectivity,high contrast,low cost and user-friendly is still urgent.To overcome this challenge,a moisture-stable,red-emitting fluoride phosphor K_(3)AlF_(6):Mn^(4+)(KAF:Mn^(4+))with an organic hydrophobic skin was prepared.The phosphor has a uniform and superfine morphology with excellent luminescence properties.More importantly,this non-ultraviolet(UV)or non-near infrared(NIR)induced phosphor was proved to be an ideal fluorescent label for LFP imaging,which is both friendly for touch DNA analysis and compatible to forensic light sources.The well-defined ridge details with little background interference on various surfaces were presented by the oleic acid(OA)modified KAF:Mn^(4+)(KAF:Mn^(4+)-OA)phosphor in few seconds using the powder dusting method.To confirm the high selectivity of KAF:Mn^(4+)-OA for LFP imaging,an efficient quantitative evaluation method is proposed with the aid of ImageJ&Origin software.Due to the superiority of the Mn^(4+)-doped fluoride for the rapid imaging of LFPs in terms of lowcost,high compatibility and good availability,it is expected to be a promising candidate for forensic science as well as fluorescence imaging in other fields instead of rare earth luminescent materials.

基于重要区域定位与掩码的射频指纹可视化分析

针对时域脉冲信号样本的射频指纹提取与深度学习模型的可解释性,提出了一种基于Grad-CAM的重要区域可视化呈现方法,并通过重要区域的多次掩码测试,来分析重要区域对射频指纹识别结果的影响。基于10个辐射源的信号样本,对比了层数不同的两种ResNet模型的测试结果。测试发现该方法能够区分不同类型信号并呈现个体差异。分析表明,该方法能够发现不同辐射源发送相同信号时的重要区域定位差异,能可视化反映辐射源个体特征的空间距离,以及不同模型的特征表征与指纹定位准确度差异;同时发现对重要区域的掩码更容易产生误预测,证明特定信号存在与时频特征相关的射频指纹,并可辅助可视化定位影响射频指纹样本识别的关键点。

发射绿色荧光的钆氮掺杂碳点/水滑石纳米复合材料对潜在指纹的识别

碳点(CDs)是一种绿色纳米荧光剂,CDs分散在水溶液中,能够呈现出良好的荧光性能。由于聚集诱导而引发荧光猝灭效应,导致固态的CDs粉末的荧光消失,这一缺陷限制了CDs的实用性。一方面通过在CDs中掺杂其他元素的方式来改变CDs的荧光发射波长和荧光颜色,提高潜在指纹(LFPs)与基材背景间的对比度;另一方面将CDs分散在低值的水滑石表面,阻止CDs的聚集,从而避免了荧光猝灭现象的产生。以酒石酸为碳源、三乙烯四胺为氮源和GdCl_(3),采用水热法先制备钆氮掺杂CDs(Gd/N-CDs),然后再将Gd/N-CDs沉积在水滑石(Gd/N-CDs@H)表面上,制备出了发射绿色荧光的纳米复合材料,并用于LFPs的成像和识别。从表征结果可知,纳米级Gd/N-CDs在水滑石表面的良好分散克服了Gd/N-CDs在固态状态下的荧光猝灭,得到了固态光致发光荧光纳米复合材料。在450 nm光的激发下,Gd/N-CD@H能发射稳定、强烈的绿色荧光,并且在各种基底(如玻璃片、铜箔、瓷砖、塑料、铝箔和纸张)呈现出清晰的LFPs图像。基于Gd/N-CDs@H,新鲜和老化LFPs图案的高级别细节都可以清晰地识别出来,并且具有良好的清晰度和高对比度,无明显的背景干扰。

悬浮液显现技术应用于潜手印的研究进展

潜手印显现技术对案件侦破和司法鉴定起着重要的作用。根据客体表面的潜手印特点,需使用不同的显现技术,如悬浮液显现技术主要用于陈旧、潮湿或粘性的客体表面,而基于新兴纳米颗粒的悬浮液显现技术还因具备优异的灵敏度、信噪比、选择性等显现性能,日益受到重视。简要介绍了目前普遍使用的传统小颗粒悬浮液显现技术,较为详细地综述了近十几年来新兴纳米颗粒(如量子点、碳纳米点、稀土发光材料、纳米氧化物等)在手印显现方面的应用进展,并概述了悬浮液显现技术的操作方法,最后分析了该技术目前所面临的挑战和未来发展方向,为其在法庭科学、公安教育等领域的应用提供参考。

影响氨基黑10B显现指纹因素的系统探究

指纹是犯罪现场的最常见物证之一,更是对犯罪嫌疑人或受害人进行同一认证的重要物证,而由于犯罪现场的复杂性,不同的环境因素会对指纹的显现结果造成影响。以瓷砖上的新鲜血手印这一室内凶案现场常见的指纹物证为研究对象,探究了不同因素对氨基黑10B显现液显现指纹的影响,表明质量分数为0.60%氨基黑10B,质量分数为25%冰乙酸的显现液是显现瓷砖上新鲜血潜手印的最佳配方,同时,该配方也适用于不同显现方法、不同承痕客体、不同浓度和不同遗留时间的血手印和显现含有蛋白质的指纹。

基于Web of Science数据库的法庭科学领域潜指纹研究文献计量分析

本文采用文献计量分析的方法,通过对2001~2018年科学引文数据库的Web of Science数据库中法庭科学领域潜指纹研究文献进行统计,以此分析全球范围内法庭科学领域潜指纹研究情况。研究发现,全球在该领域的发文量整体呈现上升趋势。目前,法庭科学领域潜指纹研究热点主要有四个:传统潜指纹显现材料或技术的研究、潜指纹的信息化研究、纳米技术在潜指纹显现中的应用研究和针对潜指纹的残留物(如成瘾物质、爆炸物等)及遗留时间等构建新型潜指纹显现材料。我国在该领域的研究有一定的影响力,但在今后的研究中要注重高水平论文的发表,同时应加强与高水平研究机构之间的合作,带动该领域研究力量的整体提升,更好地为平安中国保驾护航。该分析可为我国相关领域的研究提供参考依据。

Eu-MOF-Based Fluorescent Ratiometric Sensor by Detecting 3,4,5-Trihydroxybenzoic for Fingerprint Visualization on Porous Objects

Latent fingerprints(LFPs)at the crime scene are served as important clues to locate the trajectory of criminal behavior and portray the characteristics of the suspect.Therefore,visualizing LFPs is of considerable significance.In this work,the europium metal-organic framework(Eu-MOF)sensor was successfully constructed for sensitive detection of gallic acid(3,4,5-trihydroxybenzoic acid,GA)and visualization of the sweat LFPs.The boric-acid-modified Eu-MOF was prepared by using the simple one-pot solvothermal method using Eu as the metal i ion center and 3,5-dicarboxybenzeneboronic acid(BBDC)as the organic ligand.The sensor showed desirable photoluminescent performance through the chelating of BBDC with Eu3+.The sensor exhibited the satisfactory linear relationship to GA in the range of 1 nM to 20 nM with a low detection limit of 0.34 nM under the optimized conditions.The prepared sensor with ideal selectivity to GA was successfully applied for visualizing LFPs on porous substrates with the high contrast and superior stability.Given the good performance of the sensor,all fingerprint images obtained from 1200 samples presented clear friction ridges and met the identification criteria.Notably,the sensor had less impact on the subsequent deoxyribonucleic acid(DNA)detection,displaying a promising perspective for applications in extracting physical evidence of site investigation.

稀土发光纳米材料在手印显现中的应用进展

自2000年起,研究人员陆续将一系列新型纳米材料应用到手印显现中,由此衍生了手印纳米显现技术。显现材料的推陈出新和显现方法的借鉴创新共同促进了手印纳米显现技术的迅速发展。近十年来,将稀土发光纳米材料应用于手印纳米显现技术的研究报道日益增多,已经逐渐成为该领域的研究热点之一。基于稀土发光纳米材料的手印显现技术具有对比度强、灵敏度高、选择性佳、毒害性低等突出优势,因此具备重要的理论研究价值和广阔的实践应用前景。目前,该研究领域的文献报道形式主要为研究类文章,鲜有涉及综述类文章。该文从显现材料的推陈出新和显现方法的借鉴创新两个方面综述了稀土发光纳米材料在手印显现中的研究进展。在显现材料的推陈出新方面,总结了基于稀土下转换发光纳米材料、稀土上转换发光纳米材料、复合型稀土发光纳米材料的手印显现应用;在显现方法的借鉴创新方面,总结了基于静电吸附原理、疏水作用原理、化学键合原理、适配体识别原理的手印显现方法。基于稀土发光纳米材料的手印显现研究呈现出如下发展趋势:显现材料由下转换发光材料向上转换发光材料发展,由单一发光材料向多重发光材料发展,由光致发光材料向功能复合材料发展;显现方法由非特异显现向靶向性显现发展,由痕迹物证的定性显现向遗留物质的定量检测发展,由物理显现向化学显现发展;显现效果由痕迹特征的宏观无损向生物物证的微观无损发展;显现操作由潜在毒害向绿色环保发展;显现评估由主观、片面、定性描述向客观、全面、定量分析发展。该综述对基于稀土发光纳米材料的手印显现技术提出了如下展望:首先是纳米材料的物理性质对手印显现效果的影响研究,其次是纳米材料的诸多性质对生物物证检验的影响研究,最后是显现原理的广泛借鉴与显现方法的深度开发研究。

两种具有三苯基吡啶结构的二氟硼化合物光学性能及潜指纹成像研究

对称型三苯基取代吡啶化合物具有良好的生理活性,已被广泛应用于合成重要的有机中间体和药物结构单元中。为了进一步探究三苯基吡啶化合物的光学性能,合成了两种具有三苯基吡啶结构的二氟硼化合物。实验结果表明,由于溴原子和二甲氨基团的电荷特性不同,含有二甲氨基团的化合物具有更加显著的分子内电荷转移特性和聚集诱导发光活性。此外,含有二甲氨基团的吡啶基二氟硼化合物还显示力致荧光行为,并可作为潜指纹成像的显影剂。

ZnO荧光纳米粒子在显现潜指纹的应用研究

为了寻找制备方法简单、成本低廉、环境友好且无毒性的具有应用前景的新型非金属潜指纹显现材料,本文以醋酸锌[Zn(AC)_(2)·2H_(2)O]、氢氧化钾(KOH)为原料,采用溶剂热法合成了ZnO纳米粒子,利用X射线衍射仪(XRD)、透射电子显微镜(TEM)和荧光光谱对合成的粉体进行了表征,之后采用常规刷显的方法,对不同客体上的潜指纹进行显现。采用本方法制备得到了粒径约为8nm的ZnO纳米粒子,在254nm的紫外光照射下,ZnO纳米粒子呈现出明亮的黄绿色。该材料对指纹纹线具有较强的吸附特性,能够对锡纸、不锈钢片、玻璃、绿色塑料片、易拉罐、木质地板等非渗透性和渗透性客体表面的潜指纹进行显现,均可得到具有清晰二级特征的指纹图像。

High-Resolution Imaging of Latent Fingerprints through Near-Infrared Organoboron AIEgens

A new class of near-infrared(NIR)fluorescent organoboron AIEgens was successfully developed for latent fingerprints(LFPs)imaging.They exhibit real-time and in situ high-resolution imaging performance at 1-3 levels of LFPs by spraying method.In addition,we systematically elucidate the fingerprint imaging mechanism of these AIEgens.Significantly,the excellent level 3 structural imaging capabilities enable the application of them for analyzing incomplete LFPs and identifying individuals in different scenarios.

Green mediated synthesis of lanthanum doped zinc oxide:Study of its structural,optical and latent fingerprint application

The present paper summarises the synthesis of La3+doped zinc oxide nanoparticles using Aloe vera gel by solution combustion method and the characterization using a powder X-ray diffractometer(PXRD),a transmission electron microscope(TEM),an X-ray photometric spectrometer(XPS),a Raman spectrometer and their applications in optical devices and latent fingerprinting.PXRD pattern confirms the crystallite size of La3+doped ZnO varies from 13 to 20 nm.Crystallite size varies inversely with doping concentration.Photoluminescence properties are found to be the maximum for 2 mol% doping concentration.PL spectra extends the use of ZnO:La3+nanoparticles in blue green LED.These nanoparticles also have superior property as a fluorescent labels in fingerprints.

A Study on Automatic Latent Fingerprint Identification System

Latent fingerprints are the unintentional impressions found at the crime scenes and are considered crucial evidence in criminal identification.Law enforcement and forensic agencies have been using latent fingerprints as testimony in courts.However,since the latent fingerprints are accidentally leftover on different surfaces,the lifted prints look inferior.Therefore,a tremendous amount of research is being carried out in automatic latent fingerprint identification to improve the overall fingerprint recognition performance.As a result,there is an ever-growing demand to develop reliable and robust systems.In this regard,we present a comprehensive literature review of the existing methods utilized in latent fingerprint acquisition,segmentation,quality assessment,enhancement,feature extraction,and matching steps.Later,we provide insight into different benchmark latent datasets available to perform research in this area.Our study highlights various research challenges and gaps by performing detailed analysis on the existing state-of-the-art segmentation,enhancement,extraction,and matching approaches to strengthen the research.

心脑健制剂用茶叶提取物提取工艺初探

目的对《中华人民共和国药典》(2020年版)(简称“《中国药典》”)心脑健片项下茶叶提取物的提取工艺进行小试研究,并比较相关产品的差异,初步了解产品现状,为其药品质量控制和用药安全提供参考。方法按照《中国药典》工艺要求对8批不同来源的茶叶通过加水煎煮等步骤进行小试提取,计算提取率。建立包括没食子酸,表没食子儿茶素,儿茶素,咖啡因,表儿茶素,表没食子儿茶素没食子酸酯,没食子儿茶素没食子酸酯,表儿茶素没食子酸酯,儿茶素没食子酸酯等在内的9个指标成分的指纹图谱,并对茶叶原料、实验室制备对应茶叶提取物,从市面上收集的茶叶提取物及企业提供的茶叶提取物和心脑健胶囊进行可视化分析,比较差异。结果实验室按照《中国药典》方法制备的茶叶提取物提取率为0.3%~0.5%,据调研企业生产的茶叶提取物提取率约为5%,而从市场上购买的茶叶提取物提取率可高达20%~30%。指纹图谱结果显示,不同来源的茶叶提取物指纹图谱不同,尤其市场上购置的提取物指纹图谱差异较大。结论本研究初步探讨了茶叶提取物的提取工艺,指出现有方法和产品可能存在的问题,为完善茶叶提取物提取工艺、保障产品质量和安全提供了借鉴。

磁性荧光碳点合成与潜指纹显影性能的综合教学实验设计

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