羊脑多头蚴的超微结构观察

为观察羊脑多头蚴的超微结构,寻找自然感染羊脑多头蚴的病羊,采集多头带绦虫续绦期幼虫,固定于25mL/L戊二醛中,分别取其头节、囊壁、颈部区,超薄切片后进行透射电镜观察。结果表明,羊脑多头蚴的囊壁结构具有微毛,远离头节的囊壁微毛与头节附近颈部区囊壁的微毛分布情况不同;囊壁可明显分为皮层、间质层、实质区;在实质区可观察到皮层细胞、实质细胞、成石灰小体细胞、焰细胞、成肌细胞以及排泄系统结构;头节中可观察到很发达的肌纤维结构,头节内部有类似于囊壁的皮层结构,并可见粗大微毛,细胞种类明显少于囊壁实质区,含颗粒的囊泡结构明显增多。证明羊脑多头蚴囊壁的结构和细胞种类与其他绦虫相似,但有比较发达的排泄系统;头节外表面无皮层结构,仅有呈环状围绕的纤维和囊泡结构。     

Frozen human bone: a microscopic investigation

The taphonomic effects of prolonged extreme cold and freezing on human bone have received little research attention. Questions of specific interest include whether previously frozen bone can be identified and whether freezing alters the structural integrity enough to prevent histological aging. There is no evidence from previous studies that freezing damages the structural integrity, and to date no research investigating the freezing process on bone microstructure has been undertaken. This research attempts to distinguish histologically previously frozen bone from nonfrozen bone by identifying patterned defects. To determine the effects of freezing in bone microstructure using light and scanning electron microscopy (SEM), several human bone sections were subjected to prolonged freezing and allowed to thaw before thin sectioning. Light microscopy failed to demonstrate statistically significant differences between frozen and nonfrozen specimens. SEM analysis revealed fractures, although these lacked pattern and did not occur systematically throughout the section. Evidence of microstructural changes caused by liquid expansion, however, was remarkable but did not alter the structural integrity of the microstructure. The results of this study suggest that freezing does not alter the process of histomorphological analysis.     

Differentiating human bone from animal bone: a review of histological methods

This review brings together a complex and extensive literature to address the question of whether it is possible to distinguish human from nonhuman bone using the histological appearance of cortical bone. The mammalian species included are rat, hare, badger, racoon dog, cat, dog, pig, cow, goat, sheep, deer, horse, water buffalo, bear, nonhuman primates, and human and are therefore not exhaustive, but cover those mammals that may contribute to a North American or Eurasian forensic assemblage. The review has demonstrated that differentiation of human from certain nonhuman species is possible, including small mammals exhibiting Haversian bone tissue and large mammals exhibiting plexiform bone tissue. Pig, cow, goat, sheep, horse, and water buffalo exhibit both plexiform and Haversian bone tissue and where only Haversian bone tissue exists in bone fragments, differentiation of these species from humans is not possible. Other primate Haversian bone tissue is also not distinguishable from humans. Where differentiation using Haversian bone tissue is undertaken, both the general microstructural appearance and measurements of histological structures should be applied. Haversian system diameter and Haversian canal diameter are the most optimal and diagnostic measurements to use. Haversian system density may be usefully applied to provide an upper and lower limit for humans.     

Forensic analysis of soil and sediment traces by scanning electron microscopy and energy-dispersive X-ray analysis: an experimental investigation

This paper reports the results of a series of experiments carried out to determine the precision of soil trace comparisons based on elemental peak height ratios determined by energy-dispersive X-ray analysis (EDXRA) in a variable pressure scanning electron microscope (VP-SEM). Experiments were conducted on 'bulk' soil aggregates, ground powders prepared from the <150 microm soil fractions and on smears of both the bulk soil and <150 microm material placed on cotton cloth. X-ray count data were obtained using area scans and spot analyses at different magnifications. The effects on elemental peak height ratios of varying the SEM chamber pressure, beam spot size, emission current and accelerating voltage were also examined. The peak height ratios for oxygen, silicon, aluminium, potassium, calcium and iron were found to show little variation as a function of chamber pressure, spot size and emission current over the ranges examined, but a strong dependency on accelerating voltage was observed. Within-sample variation in results, expressed by the percentage coefficient of variation, was found to be lowest for area scan analyses of the ground <150 microm fractions and greatest for the spot analyses of the bulk soil aggregates and the <150 microm fractions. We conclude that comparison of elemental peak height ratios determined by EDXRA can be a useful tool for rapid screening of soil samples, especially when combined with investigation of other attributes of the soil traces such as colour, fabric and the composition, shapes and surface textures of individual particles or aggregates within the soil traces. If sufficient material is available and can be readily separated without contamination or loss, higher resolution and more precise elemental data should be obtained by methods such as inductively coupled plasma atomic-emission spectrometry (ICP-AES) or mass-spectrometry (ICP-MS).     

Accumulation of explosives in hair--Part 3: Binding site study

This study extends previous work on the sorption of explosives to the hair matrix. Specifically, we have studied the interaction of 2,4,6-trinitrotoluene (TNT) and triacetone triperoxide (TATP) as a function of chemical pretreatment with acetonitrile, neutral and alkaline hydrogen peroxide, methanolic KOH and potassium permanganate, and the morphological changes that accompany these treatments. While differences in vapor pressure can account for quantitative differences between TNT and TATP sorption, both are markedly affected by the chemical rinses. Examination of the hair surface shows different degrees of smoothening following rinsing, suggesting that the attachment to hair is largely a surface phenomenon involving the 18-methyleicosanoic acid lipid layer. Density functional theory calculations were employed to explore possible nucleation sites of TATP microcrystals on the hair. We conclude that some of the sites on melanin granular surfaces may support nucleation of TATP microcrystals. Moreover, the calculations support the experimental finding that dark hair adsorbs explosives better than light hair.     

一种水下金属物证探测器的设计

目的 设计一种水下金属物证探测器,用于公安人员在池塘、沟渠、水井等水域中搜寻金属类物证.方法 采用金属探测技术、水下视频采集技术和无线传输技术相结合,实现探测器的多功能特性.结果 在深度不超过4m的水域中,借助探测器可以准确搜寻到金属物证.结论 该探测器具有金属探测以及视频图像采集、无线发送和保存的功能,能满足一定范围内搜寻水下金属物证的工作需求.     

屠宰猪肝和血清中乙型肝炎病毒及戊型肝炎病毒的检测

应用1对乙型肝炎病毒(HBV)S基因保守区的引物,采用PCR方法从屠宰猪肝、血清中检测到了HBV,序列分析表明,扩增片段与已发表的HBV S基因的同源性高达98%~100%。电镜负染色样品观察结果表明,在HBV表面抗原ELISA检测强阳性反应的血清样品中存在有形态、大小与人HBV Dane颗粒和小球状颗粒相似的病毒粒子。针对戊型肝炎病毒(HEV)ORF2/ORF3重叠区设计了简并引物,采用巢式RT-PCR对屠宰猪肝和血清样品进行了检测。结果表明,部分屠宰猪肝中存在HEV。     

人为删改和破坏的硬盘数据的恢复

随着信息产业的高速发展,计算机的应用已变得越来越普遍。传统的纸张存储信息的方式也被计算机存储所替代。而信息技术本身是一项非常前沿的技术,计算机存储数据的安全性也就很难保证的。通过人为的删改和破坏数据来销毁证据的案例屡屡发生。这也就对公安工作提出了新的挑战。被修改和破坏了的数据统称损坏数据。目前,数据存储体被损坏的类型主要有软损坏和硬损坏。本文针对这两个方面在数据存储原理、恢复原理、恢复方法等内容上进行了深入的探讨。     

电子政务在政府管理创新中的实现途径

充分发挥电子政务在政府管理创新中的作用,必须加强电子政务工作领导,合理设计电子政务的建设目标,健全相关工作机构,整合人才资源,提供资金保障.     

血中毒鼠强的固相萃取和GC-NPD法测定

目的 研究人全血中毒鼠强的固相革取(SPE)。方法 用Bond Elute C18固相萃取柱萃取,GC-NPD检测,以甲基对硫磷为色谱内标(CS)。结果 全血中加标0.5μg/ml,毒鼠强回收率为92.5％,变异系数2.3％(CV,n=4)。在0.5～10μg/ml的浓度范围内,线性相关系数为0.9994。检出限(S/N=3)和定量限(S/N=10)分别为6ng/ml和20ng/ml。同一根萃取柱连续使用6次未见性能明显下降(CV=3.6%)。结论 本文方法适用于毒鼠强中毒的全血测定。