家兔烧死后气管、肺及心肌的病理形态学观察

目的探讨烧死的病理形态学依据。方法建立家兔烧死动物模型,用光镜、透射及扫描电镜观察10只生前烧死家兔气管、肺及心肌的病变;并与死后焚尸及非烧死的正常组(各5只)对照。结果透射电镜下,气管粘膜上皮完全脱落,成堆红细胞和纤维蛋白成分粘附在平滑肌表面。肺Ⅰ型上皮细胞结构基本完整连续,线粒体嵴有断裂、缺失;Ⅱ型肺泡上皮细胞微绒毛消失,多数细胞线粒体、板层小体、高尔基体未见异常,少数Ⅱ型肺泡上皮细胞质膜破损、染色质浓集、胞质内容丢失。心肌严重变性坏死,细胞膜破坏,线粒体极度肿胀,肌丝溶解并出现收缩带坏死。扫描电镜下,气管粘膜上皮有完整纤毛,但上皮大片脱落,少数区域纤毛上皮稀疏排列,有脱落柱状上皮附着在纤毛上;肺间皮细胞结构基本完整,微绒毛数量不一致;心内膜的内皮细胞大部脱落,暴露内皮下结缔组织,心肌纤维呈扭曲排列。死后焚尸及正常组对照组未见上述变化。结论烧死兔的光镜和电镜下气管、肺及心肌的病理形态学变化,能为生前烧死与死后焚尸的鉴别提供依据。     

冒充“冰毒”物-明矾的检验

目的建立明矾的检验方法。方法综合运用傅立叶红外光谱仪(FTIR)、扫描电镜/能谱仪(SEM/EDX)、气质联用仪(GC/MS)、化学法分析等方法。结果排除了常见毒品,确认无色晶体为明矾。结论用本文方法准确检验出不明白色晶体为明矾。     

大鼠闭合性弥漫性脑损伤脑血管铸型的扫描电镜观察

用扫描电镜观察闭合性脑损伤即刻致死和伤后15min大鼠脑血管铸型，发现大鼠脑震荡性损伤后，脑干穿行小动脉及其分支可见多数散在的微动脉痉挛，呈节段性变细，扭曲，血管腔直径约2—5mp。毛细血管前括约肌收缩。正常大鼠脑干实质小动脉直径约10~15mp。讨论了外伤性脑血管痉挛的机制及其对颅脑损伤后果的影响。     

两种铁铬合金电警棍遗留金属颗粒成分分析

目的检测两种电警棍铁铬合金电极遗留金属颗粒的成分,对同一电警棍电击前后遗留金属颗粒成分特征进行分析,对电警棍遗留金属颗粒成分的稳定性、差异性进行评价。方法使用电警棍分别多次摩擦滤纸和电击猪皮,使用碳导电胶带粘取遗留金属颗粒,应用SEM/EDS技术检测颗粒元素成分,并对数据进行统计学分析。结果两种电警棍电击前遗留铁铬合金颗粒及电击后遗留铁铬合金颗粒成分均稳定,存在差异;实验两种电警棍电击后遗留金属颗粒成分分布发生显著变化,除原成分铁铬颗粒外,实验猪皮表面均检出全新成分的铁铬合金颗粒,且两种电警棍电击后产生的全新铁铬颗粒成分稳定无显著差异。结论通过分析两种电警棍铁铬电极电击前后遗留多金属颗粒成分分布特征,可以实现对两种电警棍电极的识别,为人体电警棍损伤的识别与认定提供技术支持和理论依据。     

Unusual sources of Sn in GSR. An experimental study by SEM and IBA

Gunshot Residue (GSR) produced by the discharge of a firearm often provides very useful information in criminal investigations in cases involving the use of firearms. Scanning Electron Microscopy equipped with an Energy Dispersive X-ray Spectrometer (SEM-EDS) is typically used worldwide to visualize micrometric particles constituting GSR and to analyse their elemental composition. The 2017 ASTM Standard guide for gunshot residue analysis by scanning electron microscopy/energy dispersive X-ray spectroscopy specifies that “Particles classified as characteristic of GSR will have one of the following elemental compositions: Lead, antimony, barium; Lead, barium, calcium, silicon, tin”. For the first time, the presence of an additional element, such as Sn, plays a key role in ASTM particle classification. It is known that some ammunitions, used for pistols, revolvers and rifles, contain tin foil discs for sealing the primer mixture into the cup, resulting in GSR particles containing Sn. The authors faced some cases in which Sn was unexpectedly found in GSR particles from a 0.22 Long Rifle derringer and from some 12 gauge shotguns. No tin foil discs are used in rimfire ammunitions and there is no published evidence of tin foil discs in shotshell ammunitions. Following a “case by case” approach, experimental research has been carried out to explain how Sn can be present in GSR particles when the last discharged cartridge also does not contain any Sn either in components and in the explosive charges.Moreover, the use of Particle Induced X-ray Emission (PIXE) showed the capability to overcome overlap ambiguity of Sb and Sn peaks in the X-ray spectra, being a possible key issue in real shooting cases if Sn quantities are below the lower limit of SEM detection, especially when Sb is also present.     

子弹弹头及弹壳成分比较研究

目的对子弹物证进行成分分析可为涉枪案件的侦查提供科学依据。本实验旨在通过研究子弹弹头及弹壳的元素组成快速区分不同子弹,为推断子弹来源提供关键信息。方法收集不同厂家在1958-2019年不同批次生产的多种型号的子弹样品53份,应用扫描电镜能谱法(SEM/EDX)对样品的弹头内芯、弹头披甲和弹壳金属成分进行研究。结果结果显示多数子弹弹头内芯由纯铅构成,部分批次较晚的弹头为铅锑合金,另有两枚批次较早子弹为铁弹头;除六枚5.6mm运动步枪弹的弹头披甲以及四枚791厂样品的弹壳无明显特征外,其余子弹的弹头披甲和弹壳均为三类铜锌合金中的一种:含铜量83.7%~84.7%、87.6%~90.6%以及67.0%~69.8%的铜锌合金。同型号同厂家子弹所使用弹头披甲及弹壳材料的特征相似,同型号不同厂家、同厂家不同型号的子弹弹头披甲和弹壳材料则具有一定差异。近六十年来121厂样品子弹弹头披甲均为含铜量87.6%~90.6%的铜锌合金,弹壳材料为含铜量67.0%~69.8%的铜锌合金,其为该厂固定使用的铜锌合金原材料的可能性较高。791厂样品中有四种型号的子弹弹壳均为含锰量0.7%~0.9%的铁锰合金,这种合金在其他厂家并未出现,其为791厂弹壳特征原材料的可能性较高。结论掌握子弹弹头及弹壳的元素组成特征可以对不同子弹进行有效识别。     

Analytical survey of restorative resins by SEM/EDS and XRF: databases for forensic purposes

Frequently in forensic cases, unknown substances must be identified. Automated databases can ease the burden of comparison as materials may be compared against many known standards in a relatively short period of time. It has been shown that dental resins can be named according to brand or brand group even in conditions as harsh as cremation. Databases are already in use for many materials, but no such database exists for dental resins. Thus, two databases were generated. One utilized a laboratory-based method, scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM/EDS), in conjunction with the Spectral Library Identification and Classification Explorer (SLICE) software. The other was based on portable X-ray fluorescence (XRF). The ability to perform database comparison with portable instrumentation can thus be brought directly to the field. Both the SLICE and XRF databases were evaluated by testing unknown resins. EDS is a well-established technique and the SLICE program was demonstrated to be a good tool for unknown resin identification. Portable XRF is a relatively new instrument in this regard and its databases have been constructed mostly for metal alloy comparison and environmental soil testing. However, by creation of a custom spectral library, it was possible to distinguish resin brand and bone and tooth from other substances.     

Electoral alliance with sworn opponent political party: factors impacting voting intention

Alliance with sworn political opponents is becoming a growing phenomenon within the realm of political alliances. Here, two or more competitive political parties join hands to defeat a particular common opponent. During election, alliance partners face election together and distribute electoral seats mutually to avoid vote share. However, ensuring vote in favour of opponent alliance candidate is only possible when voters prefer to cast vote for the alliance candidate. Thus, this is crucial to know influencing factors that shape voters’ voting intention in favour of opponent alliance candidate. This study is an attempt to empirically investigate factors that have significant influence to shape voters’ voting intention for opponent alliance. The result shows that opponent alliance perceived fit impacts opponent alliance voting intention positively. Opponent alliance brand trust has a positive impact on opponent alliance voting intention. In addition, opponent alliance preference impacts opponent alliance voting intention positively.     

Development of a quantitative LC-MS/MS method for the analysis of common propellant powder stabilizers in gunshot residue

In traditional scanning electron microscopy/energy dispersive X-ray analysis of gunshot residue (GSR), one has to cope more and more frequently with limitations of this technique due to the use of lead-free ammunition or ammunition lacking heavy metals. New methods for the analysis of the organic components of common propellant powder stabilizers were developed based on liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). A multiple reactions monitoring scanning method was created for the screening of akardite II, ethylcentralite, diphenylamine, methylcentralite, N-nitrosodiphenylamine, 2-nitrodiphenylamine, and 4-nitrodiphenylamine, present in standards mixtures. Five out of seven of these target compounds can be selectively identified and distinguished from the two others with a high accuracy. Samples from the hands of a shooter were collected by swabbing and underwent solid phase extraction prior to analysis. Detection limits ranging from 5 to 115 mug injected were achieved. Results from several firing trials show that the LC-MS/MS method is suitable for the detection of stabilizers in samples collected following the firing of 9 mm Para ammunitions.     

SEM/EDS法和XRF法在电工胶带检验中的应用

目的探索电工胶带带基的元素检验方法。方法利用扫描电镜/能谱法（SEM/EDS）对电工胶带带基中的主体元素进行定量分析,通过SPSS软件对SEM/EDS定量分析法检测出的主体元素（Cl和Ca）相对含量进行统计分析;利用X射线荧光光谱法（XRF）对电工胶带带基中的微量元素进行定性分析。结果34个品牌红色电工胶带组成的561组样品对通过SEM/EDS定量分析法可以区分539组,区分率达到96.1%;根据XRF法定性分析测出的Mg、Al、Si、S、Ti、Sb、Ba、Pb微量元素的不同组合可将34种电工胶带分成11组,两种方法结合可使不同品牌红色电工胶带的区分率达到98.4%。结论SEM/EDS法和XRF法结合可以实现同种颜色、不同品牌电工胶带的高效区分。