高效液相色谱法测定水中的草甘膦

目的建立强极性除草剂草甘膦的高效液相检验方法;方法采用离子交换液相色谱法分离,经柱后衍生化以荧光检测器定性检测样品中草甘膦;结果经该方法检测草甘膦的最低检测限为5ng/ml(S/N≥3);结论该方法快速、灵敏、准确,为此类案件的检验提供了科学依据。     

应用扫描电镜能谱仪检测电击伤皮肤表面的金属元素——附一例案例报告

作者采用已知化学组成的导体对家兔进行触电试验。取受损部位的皮肤作常规处理,用带能谱的扫描电镜作金属离子测定,仪器型号为 JXA-840-LinK-860。对检出的金属元素,进行了定性和半定量分析,并观察了元素的分布。作者在一例人体电击伤皮肤活检标本上检出铁元素,而对照皮肤则无,从而认定是含铁的导体与皮肤接触。电击伤与热烫伤的超微结构变化能区别。     

Analysis and discrimination of electrical tapes: Part I. Adhesives

This study involved the comparative analysis and discrimination of 90 electrical tape adhesives. The objectives included the evaluation of the ability of individual techniques to discriminate samples and the assessment of the ability of the techniques combined to distinguish samples. The techniques utilized were stereomicroscopy, Fourier transform infrared spectroscopy (FTIR), pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS), and scanning electron microscopy/energy dispersive spectroscopy (SEM/EDS). Stereomicroscopy, to assess adhesive colors of black, clear/colorless, and clear adhesives with brown tint, resulted in a discrimination of 53%. FTIR analysis yielded eight distinct groups with a discrimination of 67%. Py-GC/MS analysis resulted in 16 groups with a discrimination of 83%. These analyses confirmed and further subdivided the FTIR groups. SEM/EDS resulted in five separate groups at 17% discrimination, increasing the overall discrimination to above 85%.     

Differentiation of traumatic and heat-induced dental tissue fractures via SEM analysis

Previous studies have examined the effects of heating on teeth; however, none have identified characteristics that allow analysts to differentiate traumatic from heat-induced fractures. This study examined our ability to discern notable differences in preincineration traumatic fractures and heat-induced fractures in postincineration dentition. Twelve anterior dental specimens were subjected to blunt force trauma while a second set were not. All 24 samples were then incinerated in a muffle furnace at a peak temperature (900°C) consistent with house fires. The specimens were subsequently examined with a scanning electron microscope to identify and compare heat-induced and traumatic fractures. The results obtained during examination yielded no differences between the features displayed by specimens that had been inflicted with preincineration trauma and those that did not. Unlike bone, distinguishing features for the differentiation of traumatic and heat-induced fractures could not be compiled.     

对纤维蛋白诊断生前伤的评价——45例枪弹创组织的MSB染色和扫描电镜对比观察

生活反应是诊断生前伤的主要根据.近二十年来,法医病理学在研究生前伤和死后伤的诊断中,采用了多种新兴技术,如扫描电镜技术、酶组织化学技术、酶标技术、电泳技术等,促使生前伤的诊断水平有明显提高.伤后存活1小时死亡者,大部分皆可获得明确诊断;立即死亡或在濒死期形成的损伤,由于生活反应甚微,或受腐败等     

数码照相机与视频荧光鉴别仪的物证检验应用比较

索尼SONY WVC-CD300数码照相机与SYJ-5型视频荧光鉴别仪应用在文件检验时,视频荧光鉴别仪部分功能可用 该种数码照相机代替,各具特色。     

Pyrotechnic reaction residue particle analysis

Pyrotechnic reaction residue particle (PRRP) production, sampling and analysis are all very similar to that for primer gunshot residue. In both cases, the preferred method of analysis uses scanning electron microscopy to locate suspect particles and then uses energy dispersive x-ray spectroscopy to characterize the particle's constituent chemical elements. There are relatively few times when standard micro-analytical chemistry performed on pyrotechnic residues may not provide sufficient information for forensic investigators. However, on those occasions, PRRP analysis provides a greatly improved ability to discriminate between materials of pyrotechnic origin and other unrelated substances also present. The greater specificity of PRRP analysis is the result of its analyzing a large number of individual micron-sized particles, rather than producing only a single integrated result such as produced using standard micro-analytical chemistry. For example, PRRP analyses are used to demonstrate its ability to successfully (1) discriminate between pyrotechnic residues and unrelated background contamination, (2) identify that two different pyrotechnic compositions had previously been exploded within the same device, and (3) establish the chronology of an incident involving two separate and closely occurring explosions.     

Zur ultrastruktur vitaler,postmortaler und autolysierter gerinnsel

Investigations on animal experimental and human tissue material (skin, musculature, liver) with the scanning electron microscope are reported. These studies were carried out to clarify open questions on extravascular fibrin structures after blunt and sharp traumatization of vital and postmortem nature. The network formation which was already characterized earlier as typically vital and the irregular structure of postmortem coagula could be demonstrated even with modification of the traumatization, especially in tissue hematomas. Experimental investigations on autolysis revealed an exceedingly good preservation of the structure of vital coagulum material with massive damage and granular decomposition of fibrin fiber structures produced postmortem. The structural differences in the mode of interlinking of the fibrin was shown up especially clearly by the autolysis, which suggests an application as preparation technique for the question specified.Special modifications of the preparation technique (fixation according to Karnovsky, critical-point drying) did not provide such substantial advantages for routine investigations that they might be generally recommended.Sources of artefacts and possibilities of misinterpretation of findings as well as more advanced techniques are discussed.     

Identification of wires and the cutting tool by scanning electron microscope

The cut ends of aluminium and copper wires made by different pliers have been compared under the scanning electron microscope to correlate the two pieces of a wire and to identify the cutting tool. The mechanism of producing the cut ends has been discussed. Matching of extrusion marks and correspondence of breakages at the edges of the cut ends were observed. Correspondence between the fine striations was observed on the opposite faces. These features are put forward for assigning a cut wire to a source.The ends produced by repeatedly cutting a wire by the same portion of the edge of a pair of pliers have been compared. It was found that the striations and fracture zones were reproduced on the respective surfaces of the consecutive cut ends. To identify the cutting tool in wire theft cases, it is suggested that the trial cut ends can be made by cutting the wire with successive portions of the edge of the suspected tool and compare the surface features with that on the questioned ones.     

SD大鼠闭合性小脑挫伤的透射电镜观察

目的　探讨闭合性小脑挫伤病变发生发展过程。　方法　建立闭合性小脑挫伤动物模型 ,分别于损伤后不同时间组 5min、10min、3 0min、45min、60min、2h、4h、6h、8h、12h与正常组对照 ,观察其电镜变化。　结果　损伤后不同时间组 ,小脑蒲肯野氏细胞线粒体水肿、空泡化从轻到重 ,线粒体嵴逐渐消失。神经纤维髓鞘疏松断裂 ,神经原丝及微管结构模糊 ,并随着时间推移 ,其损伤越来越重。损伤后 3 0min ,线粒体胞浆中充满了游离核糖体。损伤后 1～ 2小时小脑蒲肯野氏细胞胞浆浓缩 ,细胞核开始发生染色质边集。个别细胞核发生核溶解。至 4～ 6小时小脑蒲肯野氏细胞细胞核坏死发展到高峰 ,然后逐渐减轻。损伤后 8小时 ,小脑血管内皮细胞线粒体水肿 ,嵴消失 ,神经纤维髓鞘松解 ,胶质细胞核周间隙扩张。　结论　闭合性小脑挫伤后不同时间电镜变化 ,为早期损伤时间推断的法医学鉴定提供了病理学基础。