灰尘减层手印提取的实验研究

通过采用油熏法、“502”胶熏法、制模法、“502”胶碘熏法对各种客体上的灰尘减层手印提取固定进行了研究分析,并探讨了其特点、适用场合、差异的原因以及相关建议和应注意的问题.实验结果显示,这几种方法能简单、快速、有效地提取灰尘减层手印.     

几种情况下的灰尘足迹静电提取方法比较

通过灰尘足迹静电提取方法的原理的阐述,结合具体实验,归纳了静电提取灰尘足迹的几种方法适用的客体,并总结了各种操作中的注意事项。     

Toner Particles as Forensic Evidence: Microanalytical Characterization of Known Toner and Recognition of Toner in Environmental Samples*†‡

Modern printing toners represent a prime example of subvisible particles that can be easily transferred to hands, clothing, and other surfaces. To explore the potential evidentiary value of toner particles, toner samples were collected from known printer cartridges and characterized by various microanalytical techniques to establish the properties most useful for recognition, identification, and comparison. Environmental samples (i.e., dust) were then collected from various locations at varying distances from toner-based printers, using both tape lifts and carbon adhesive stubs, to assess the possibility of detecting toner. By light microscopy, toner can be recognized on the basis of particle size and shape, as well as color. Further examination of the micromorphology in the field emission scanning electron microscope reveals characteristic morphologies and differences in surface texture and shape among toner sources. Raman spectroscopy provides chemical identification of the pigment (or pigment class) and, in some cases, also permits identification of the polymer component. While black and blue pigment chemistry remained constant among toner varieties that were studied (copper phthalocyanine and carbon black), variation in yellow and magenta pigments was observed. Analysis of dust samples collected from various environments demonstrated that while toner is consistently detectable in close proximity to printers (within 2 feet), it also can be detected in dust collected in nearby rooms. This research demonstrates that toner particles can be located, characterized, and discriminated, using a suite of microanalytical methods that are applicable to forensic casework.     

The Analysis of 3D Printer Dust for Forensic Applications,,

3D printers are becoming increasingly efficient and economical, and thus more widespread and easily accessible to consumers and businesses. They have been used to print nefarious objects such as guns and suppressors. Previous research has documented the release of dust particles during the printing process; however, little has been written about the morphology and chemical features that define the dust emitted by these printers. This study was undertaken to recover, analyze, and identify the dust produced during the printing process in the context of forensic trace evidence analysis. Samples were collected from a variety of 3D fused deposition modeler printers, representing both consumer and commercial grade models. This work focused on printers that use thermoplastic filaments composed of acrylonitrile butadiene styrene (ABS) or polylactic acid (PLA), two of the most commonly used filament polymers. Swabs were used to collect dust within the printer chamber and then processed to isolate the dust particles. Particles produced from ABS filaments are most easily recognized via light microscopy through a combination of color, morphology, and fluorescence. The composition of these particles can be confirmed through analysis by either FTIR or Raman microspectroscopy. These methods can also be used to identify ABS fillers and pigments within the printer dust particles. In contrast, dust from PLA printers consistently contained finer, submicron-sized particles that could be observed by field emission scanning electron microscopy. Because the size of the particles precludes their identification using vibrational spectroscopy methods, pyrolysis-GC-MS was used to confirm the presence of PLA.     

论如何加强民营小型化工企业的消防安全

化工企业生产规模不断扩大,生产中所涉及的物质中可燃有机物所占的份额不断增大,而且生产本身又具有生产方法多种多样、装置规模大型化和生产工艺高参数的特点,这些因素决定了化工企业具有较大的火灾危险性。本文针对化工企业火灾的特点、成因,对化工企业火灾防治进行了研究,分析了化工企业中存在的火灾危险及薄弱环节,结合实际情况提出了相应的预防措施。结果表明有效的火灾预防措施能最大限度地减少发生火灾爆炸事故的机率。因此,及时有效地对化工企业中存在的潜在危险做好预防措施是十分必要的。     

东亚区域经济合作中的云南易制毒特殊化学物品管理模式探析

随着东亚区域经济合作步伐的加快,控制与阻断易制毒特殊化学物品的非法流通,在遏制境外毒品犯罪的祸源上寻求最新管理模式显得十分紧迫与必要。1、管理应由传统的“垂直型”向“扁平化”和“网络化”发展;2、应由单一的“自拉自唱”向“战略联盟”管理模式转变;3、应由单一型知识结构向“复合型”的人才升级转变。     

高速公路化危品槽车突发事故救援对策初探

近年来，随着我国高速公路的不断延伸，参与高速公路化危品槽车突发事故的抢险救援工作已成为各级消防部队面临的一个新课题，本文从分析掌握高速公路化危品槽车突发事故的特点等5个方面入手，就应采取的抢险救援对策进行了深入探讨。     

Using FastID to analyze complex SNP mixtures from indoor dust

Forensically relevant single nucleotide polymorphisms (SNPs) can provide valuable supplemental information to short tandem repeats (STRs) for investigative leads, and genotyping can now be streamlined using massively parallel sequencing (MPS). Dust is an attractive evidence source, as it accumulates on undisturbed surfaces, often is overlooked by perpetrators, and contains sufficient human DNA for analysis. To assess whether SNPs genotyped from indoor dust using MPS could be used to detect known household occupants, 13 households were recruited and provided buccal samples from each occupant and dust from five predefined indoor locations. Thermo Fisher Scientific Precision ID Identity and Ancestry Panels were utilized for SNP genotyping, and sequencing was completed using Illumina^® chemistry. FastID, a software developed to permit mixture analysis and identity searching, was used to assess whether known occupants could be detected from associated household dust samples. A modified “subtraction” method was also used in FastID to estimate the percentage of alleles in each dust sample contributed by known and unknown occupants. On average, 72% of autosomal SNPs were recovered from dust samples. When using FastID, (a) 93% of known occupants were detected in at least one indoor dust sample and could not be excluded as contributors to the mixture, and (b) non-contributor alleles were detected in 54% of dust samples (29 ± 11 alleles per dust sample). Overall, this study highlights the potential of analyzing human DNA present in indoor dust to detect known household occupants, which could be valuable for investigative leads.     

潜血印迹显现方法研究进展

潜血印迹一般出现在恶性刑事案件当中,能够反映与案件有关的多方面信息,对于同一认定和分析判断案情具有十分重要的作用,这就使得其显现成为现场勘查的一项必不可少的工作。然而,这也正是公安实践工作当中的难点所在。经过多年的实验研究,目前国内外针对于潜血印迹的显现方法主要包括光学显现法和化学显现法。综述了这些常用显现方法的研究进展,并且讨论了每种显现方法在实践工作当中的优势和不足。     

The Identification of Spiromesifen,a Recently Introduced Pesticide,Using Approaches to Chemical Unknown Analysis

An unknown, viscous, opaque, white liquid with a strong, unpleasant odor was submitted with a request for identification. It was analyzed using infrared (IR) spectroscopy, gas chromatography–mass spectrometry, and X‐ray fluorescence spectroscopy. It was found to contain glycerin as well as another compound. IR and mass spectral data were readily obtained for this second component, but it was not easily identified as common instrument libraries had no matching spectra. After an extensive literature search, the unknown compound was identified as spiromesifen, a recently introduced pesticide. The IR spectrum and electron impact mass spectrum of spiromesifen are presented here as these are not available in the published literature. This case report also provides useful approaches for searching for and identifying an unknown compound when it is not found in a laboratory's spectral libraries.