仔猪睾丸组织体外培养方法的建立

以30日龄仔猪睾丸组织块为培养对象,应用飞利普TECNAI10电子显微镜对培养前后的生精细胞类别进行了观察,对培养后的组织块进行生精细胞分化程度鉴定,建立了仔猪睾丸组织生精细胞爬片体外培养模型。培养前后电镜观察及HE染色结果显示,培养前细胞种类主要有2种:支持细胞和精原细胞,有少数几个初级精母细胞;培养第20 d的睾丸组织块HE染色观察到3个精子细胞,电镜观察到2个精子细胞。证实,在没有添加睾酮的情况下,此培养体系能够提供睾丸组织块生精细胞分化所需要的条件,使非精子细胞类生精细胞减数分裂为精子细胞。     

胚兔牙囊发育生物行为的组织形态学观察

研究胚兔的牙囊发育生物行为与人的牙囊发育是否相似 ,为人口腔疾病的研究提供模拟实验动物模型 ,采用光镜、电镜及激光扫描共聚焦显微镜对 4 3只胚兔的牙囊发育过程进行形态学观察。结果显示 ,牙囊来源于外胚间质 ,通过胚胎诱导形成牙支持组织 ,分化产生成牙骨质细胞、成骨细胞、成纤维细胞 ,形成牙骨质、固有牙槽骨、牙周韧带及其基质 ,对牙齿发育阶段具有保护和稳定作用 ,调控未来形成的牙周结构 ,在早期发育阶段首先出现 ,与人牙囊发育基本相似 ;最终牙囊在牙冠的顶部形成索引带 ,诱导继承牙萌出 ,在牙冠的根部形成牙支持组织 ,一部分牙囊细胞有程序性细胞死亡 ,以维持牙囊发育期内环境的生理平衡     

尿液分析仪检验血尿在法医学中应用研究

尿液分析仪检验血尿在法医学中的应用价值。应用尿液分析仪干化学法及尿沉渣显微镜法对 418例患者尿样红细胞成份同时进行检测 ,结果表明 ,尿液分析仪检验结果 :阴性 2 76例、“ +” 5 8例、“ ++” 35例、≥“ ++” 84例 ,尿沉渣镜检法相应程度的检验结果分别为阴性 2 74例、“ +-”和“ +” 31例、“ ++” 1例、≥“ ++” 37例 ,相同的程度符合率分别为 99 2 6 %、 5 3 45 %、 2 86 %、 44 0 5 %。两法阳性与阴性结果及轻伤程度 (≥ ++)与轻微伤程度 (≤ +)结果比较均有高度显著性差异 (P <0 0 1)。尿液分析仪检验阳性率高于尿沉渣镜检法 ,且表现血尿程度略严重。尿液分析仪检验结果阴性和“ +”与尿沉渣镜检法 0～ 3/HP (阴性或少许 )程度一致 ,属正常范围。目前 ,法医学鉴定中用尿液分析仪检验结果 2 5 / μl ( ++)相当于尿沉渣镜检法红细胞 10～ 30 /HP ( ++) ,引用《人体轻伤鉴定标准 (试行 )》第 36条进行法医学鉴定是不准确的 ,不能将尿液分析仪完全替代尿沉渣镜检法用于法医学鉴定     

Assessment of Maceration Techniques Used to Remove Soft Tissue from Bone in Cut Mark Analysis

Maceration techniques employed in forensics must be effective without compromising the bone's integrity and morphology, and prevent destruction of evidence. Techniques must also be fast, safe, easily obtainable and inexpensive; not all techniques currently employed are appropriate for forensic use. To evaluate the most suitable approach, seven techniques including current and new methodologies were applied to fresh, fleshed porcine ribs exhibiting cut marks. A sample size of 30 specimens per technique was examined under scanning electron microscopy at the cut mark and the surrounding uncompromised regions; a scoring system of effectiveness was applied. The previously unpublished microwave method fared best for bone and cut mark preservation. Sodium hypochlorite destroyed cut marks, and was deemed unsuitable for forensic analysis. No single technique fulfilled all criteria; however, this study provides a benchmark for forensic anthropologists to select the most appropriate method for their situation, while maintaining the high standards required by forensic science.     

Lead-free primer residues: a qualitative characterization of Winchester WinClean, Remington/UMC LeadLess, Federal BallistiClean, and Speer Lawman CleanFire handgun ammunition

The elemental composition and postfiring residues of several "lead-free" or "nontoxic" centerfire handgun ammunition types currently available to the general public were examined. Offerings from Winchester, Remington/UMC, Federal and Speer were obtained from retail sources in both .45 ACP and 9 mm when possible. A total of 112 postfiring residue samples (SEM pins) were collected at varying distances from the muzzle, at two distances from target and from the shooter's hands. An additional 20 samples were collected by direct ignition of primers. Qualitative determinations were carried out using scanning electron microscopy (SEM)/electron dispersive spectrometry (EDS) analysis. All types tested contained aluminum (Al), silicon (Si), copper (Cu), and zinc (Zn). Most contain traces of sulfur and calcium. Winchester WinClean and Remington LeadLess contained potassium as the principle ingredient. Federal BallistClean contained barium, while Speer Lawman CleanFire contained strontium. In the main, these compared favorably with manufacturers' MSDS publications and patents granted. The characterizations undertaken here will be of use to the forensic electron microscopist as these formulations gain popularity.     

Nanoscale analysis of the interaction between cyanoacrylate and vacuum metal deposition in the development of latent fingermarks on low-density polyethylene

Vacuum metal deposition (VMD) has been previously demonstrated as an effective development technique for latent fingermarks and in some cases has been shown to enhance prints developed with cyanoacrylate (CA) (superglue) fuming. This work utilizes scanning electron microscopy (SEM) to investigate the interactions of the two development techniques when applied to latent fingermarks on low-density polyethylene. CA is shown to act principally on the eccrine deposits around sweat pores, where polymerization results in long polymer fibrils a few 100 nm in width. Subsequent VMD processing results in additional areas of development, for example, between pores. However, the primary mode of deposition of zinc is by interaction with the polymerized CA, the fibrils of which become decorated with zinc nanoparticles. Areas with limited CA deposition and no significant polymerization are also enhanced with the VMD process, resulting in increased print development.     

微波消解-扫描电镜联用法在溺死诊断中的应用

目的探讨微波消解-扫描电镜联用法在溺死诊断中的应用价值。方法收集已知死因的尸体标本105例,其中水中尸体85例(生前溺死70例,死后抛尸入水15例),陆地自然死亡尸体20例。水中死亡案例同时收集落水处水样。分别用微波消解-扫描电镜联用法(方法 A)和硝酸破机-光镜联用法(方法 B)对上述尸体的离体肺、肝、肾、骨髓组织及水样进行硅藻定性、定量检测。结果①溺死尸体的肺、肝、肾、骨髓中及落水处水样硅藻检出率:A法分别为100%、94.3%、92.9%、82.9%、100%,硅藻检验阳性率为100%;B法分别为90%、62.9%、51.4%、28.6%、92.9%,硅藻检验阳性率为65.7%。②两种方法检出的硅藻种类与落水处水样中硅藻的种类均一致。③两种方法在死后入水尸体离体的肺中也检出少量硅藻(<3个/2g肺组织),但在死后入水尸体的其它脏器及陆地自然死亡尸体脏器中均未检出硅藻。结论微波消解-扫描电镜联用法较硝酸破机-光镜联用法对尸体离体组织脏器中的硅藻检出率高,方法灵敏,定性准确。     

Infrared Spectra of U.S. Automobile Original Finishes (1998–2000). IX. Identification of Bismuth Oxychloride and Silver/White Mica Pearlescent Pigments Using Extended Range FT‐IR Spectroscopy,XRF Spectrometry,and SEM/EDS Analysis

Bismuth oxychloride (BiOCl) was the first viable synthetic pearl pigment developed 50 years ago. It was only used for a limited time period in automotive paint (model years 1998–2000), serving to produce luster for a single Chrysler black metallic color. Identification of this pigment in an unknown automotive paint can thus facilitate determination of the vehicle of origin. Bismuth oxychloride imparts effects similar to those produced by silver/white mica pearlescent pigments, and such a pigment was used together with bismuth oxychloride in at least one original equipment manufacturer (OEM) basecoat. Silver/white micas are now used primarily in white pearl tricoat systems. This article describes the identification of bismuth oxychloride and silver/white mica pearlescent pigments in automotive finishes using FT‐IR spectroscopy, X‐ray fluorescence (XRF) spectrometry, and SEM/EDS analysis. Data for some cadmium pigments, which were used in automotive paint several decades ago, are also presented as they produce infrared absorptions similar to that of bismuth oxychloride.     

Use of laser-scanning confocal microscopy in the detection of diagenesis in bone

This research demonstrates the value of laser scanning confocal microscopy (LSCM) as a research tool in osteological studies, and diagenetic studies in particular. LSCM combines properties of light and scanning electron microscopy using laser light to excite fluorophores throughout the z-axis, developing a 3-D image. Using differential staining and selecting for specific wavelengths of light, one can image targeted materials. This research is divided into two parts: visualizing bone structures such as proteins and their decompositional products and visualizing diagenesis. Part one of this study utilized pig bones as a means of testing the overall ability of LSCM to fluoresce bone. Twenty-three samples were imaged, including 13 samples from a decompositional study conducted 5 years previous, and 10 “fresh” samples collected from a commercial butcher. This part of the study determined that protein and organic components of the bone could be fluoresced and diagenetic alteration could be imaged. The second part of the study used human samples as a means of imaging and mapping diagenetic alterations. The second part of the study used 13 samples, including 4 clinical, 7 ancient, and 2 modern controls. The pig study used Basic Fuchsin and SlowFade Gold stains, while the human study used toluidine blue. Images were also taken with unstained elements. The results of the non-human study found that a fresh bone fluoresced differently than that of a 5-year subset, while the results of the human study confirmed these findings and determined that the bone diagenesis can be mapped using LSCM.     

Combined Collection and Analysis of Inorganic and Organic Gunshot Residues

Gunshot residue (GSR) analysis and their interpretation provide crucial information on a criminal investigation involving the use of firearms. To date, several approaches have been proposed for the implementation of a combined sampling and analysis of inorganic (IGSR) and organic GSR (OGSR). However, it is not clear at this stage if concurrent analyses of both types of residue might be detrimental to the analysis of IGSR currently applied in forensic laboratories. Thus, this work aims to compare and evaluate three different protocols for the combined collection and analysis of IGSR and OGSR. These methods, respectively, involve the use of a modified stub (with two halves, one for the detection of IGSR and the other for the analysis of OGSR); the sequential recovery of GSR with two stubs mounted with different adhesives (double-sided carbon tape and Tesa® TACK) and the sequential analysis of IGSR and OGSR from a single carbon stub following carbon deposition. The detection of IGSR was carried out using SEM-EDX, while OGSR analysis was performed using ultra-high-performance liquid chromatography–tandem mass spectrometry (UHPLC-MS/MS). Obtained results for experiments performed using Geco Sinoxid^® ammunition indicated that sequential analysis was the most suitable protocol for the combined collection and analysis of both IGSR and OGSR. A higher number of inorganic (characteristic and consistent) particles and higher concentrations of ethylcentralite, N-nitrosodiphenylamine, diphenylamine, and nitroglycerin were recovered with this method.