我国法医昆虫学的研究进展

法医昆虫学是应用昆虫学知识解决有关法律问题的法医学分支学科。在推断死亡时间等方面具有明显优势。本文在阐述法医昆虫学定义和研究内容基础上,综述尸体上的昆虫生态群落演替现象、昆虫发育形态学、DNA分析技术的应用、法医昆虫毒理学等法医昆虫学问题在我国的研究进展。     

死后离体人肝组织的激光共聚焦显微拉曼光谱分析

目的观察和探讨人死后肝组织细胞激光共聚焦显微拉曼光谱的变化规律及其与死亡时间的关系。方法离体肝组织于死后48～72h内每隔4h提取样品,采用激光共聚焦显微拉曼光谱技术进行检测。观察800cm-1～3 200cm-1范围内检测样本特征峰的变化,指认其对应的化学基团,选择强度比值I1094/I2923作为响应值,并进行统计学计算。结果在48～72h内,随时间的延长,肝组织细胞主要散射峰峰位无明显变化,而其峰强度有明显差异;与核酸有关的峰（1 094cm-1）强度随时间推移有明显下降;与脂类有关的峰（1 454cm-1、2 923cm-1）强度变化不明显;各相对峰强（I1094/I2923）随死亡时间的推移而减小,并得到回归方程（r=0.914）。结论人死后肝组织细胞DNA降解随死亡时间延长呈下降趋势,I1094/I2923值与PMI呈负线性关系。激光共聚焦显微拉曼光谱技术有望成为推断死亡时间的检测方法。     

磁性纳米复合材料在法医学领域中的应用展望

磁性纳米复合材料用于生物分离具有许多优势,在法医领域具有广阔的应用前景,本文就其技术特点和在生物分离上的应用进行简要综述。     

Visualization of latent fingerprints using fluorescence lifetime imaging on paper emitting strong fluorescence

Latent fingerprints were successfully visualized using fluorescence lifetime imaging (FLIM) on paper which emits strong fluorescence with a lifetime close to that of fingerprints and thus from which it is difficult for time-resolved spectroscopy to visualize fingerprints. Latent fingerprint samples on paper were excited using a 450 nm or 532 nm nanosecond pulsed-laser, and time-resolved fluorescence images were obtained at a delay time of 6–16 ns in intervals of 1 ns, to the excitation pulse. The excitation beam was expanded using a lens, and the fluorescence from the fingerprints was captured using an intensified CCD camera. Because of the large fluorescence intensity of the background paper of approximately two to four orders of magnitude larger than that of the fingerprint, the fingerprint was not visualized on each fluorescence image by time-resolved spectroscopy. However, the fingerprint was visualized in a FLIM image constructed using a series of the fluorescence images for the case with the fluorescence intensity of the background paper being four orders of magnitude larger than that of the fingerprint. The difference in fluorescence lifetime in the FLIM image of the visualized fingerprint and background paper was in the order of 0.1 ns, which was an order of magnitude smaller than the inherent fluorescence lifetime of a few nanoseconds for the fingerprints and paper. It was demonstrated that, at a background fluorescence intensity with a certain order of magnitude larger than that of fingerprints, FLIM has the potential to visualize latent fingerprints which cannot be visualized by time-resolved spectroscopy.     

Infrared Imaging of the Crime Scene: Possibilities and Pitfalls

All objects radiate infrared energy invisible to the human eye, which can be imaged by infrared cameras, visualizing differences in temperature and/or emissivity of objects. Infrared imaging is an emerging technique for forensic investigators. The rapid, nondestructive, and noncontact features of infrared imaging indicate its suitability for many forensic applications, ranging from the estimation of time of death to the detection of blood stains on dark backgrounds. This paper provides an overview of the principles and instrumentation involved in infrared imaging. Difficulties concerning the image interpretation due to different radiation sources and different emissivity values within a scene are addressed. Finally, reported forensic applications are reviewed and supported by practical illustrations. When introduced in forensic casework, infrared imaging can help investigators to detect, to visualize, and to identify useful evidence nondestructively.     

Effect of Temperature on Six Different Developmental Landmarks within the Pupal Stage of the Forensically Important Blowfly Calliphora vicina (Robineau‐Desvoidy) (Diptera: Calliphoridae)

This study investigates the pupal development times of the blow fly Calliphora vicina, which were studied in the laboratory at six different constant temperatures (15, 20, 23, 25, 28, and 30°C each ± 1°C). Lower thresholds (t_L) for development were estimated from the linear regression of the developmental rates on each temperature. These data have made it possible to calculate the accumulated degree days (ADD) necessary for C. vicina to complete the larval stage and to achieve adult emergence. The minimal duration of development from oviposition to adult emergence was found to be inversely related to temperature. Additionally, six landmarks in pupal development are showed, and for each of the landmarks, the ADD value was calculated for every rearing temperature involved. These data assist in calculating the duration of the pupal stage based on morphological characteristics and would be of great value for future forensic entomological casework.     

3种特殊染色在急性心肌梗死死后诊断中的应用比较

目的对比观察苏木素-碱性复红-苦味酸染色(HBFP染色)、变色酸2R-亮绿染色和Heidenhain染色在急性心肌梗死死后诊断中的应用价值。方法以大鼠急性心肌梗死模型、法医检案急性心肌梗死心脏标本作为研究对象,采用HBFP染色、变色酸2R-亮绿染色和Heidenhain染色进行对比观察。结果①3种特染方法在大鼠心肌缺血15min时均可观察到阳性染色,且阳性染色面积随缺血时间的延长而扩大;②大鼠急性心肌缺血4h心脏标本在-20℃、4℃及室温条件下保存至14d,3种特染方法仍可见阳性着色,但变色酸2R-亮绿染色和HBFP染色随保存时间的延长而出现着色能力下降,阳性区域变小的趋势,Heidenhain染色效果最为稳定;③急性心肌梗死检案标本中,3种特染方法均可显示缺血心肌纤维,发病1h内死亡者Heidenhain染色优于另外两种染色。结论 3种特染均可客观的显示出急性心肌梗死早期病理改变,其中Heidenhain染色更具稳定性和可操作性。     

丽蝇科蝇类的生物学特性及其法医学应用

双翅目（Diptera）丽蝇科（Calliphoridae）蝇类是最早出现在腐败尸体、尸块上的主要蝇类。在法医昆虫学领域,根据丽蝇科的生活特性,可以较准确地推断出凶杀案或无名尸案的死亡时间（postmorteminter．val,PMI）,为案件侦破提供有利线索。本文介绍了丽蝇科蝇类的生物学、形态学特征,并对其在法医昆虫学与分子生物学、数学形态学、法医毒理学方面的联合应用进行了综述。     

American Atrocity Revisited: National Identity,Cascading Frames,and the My Lai Massacre

This study draws on the “cascading activation” model of press-state relations to explore U.S. political and news discourse surrounding the 1968 My Lai Massacre. We systematically analyze White House, military, congressional, and news communications and draw upon scholarship in social psychology to assess why the press might challenge certain frames in response to My Lai but indiscriminately echo others. In particular, within these communications, we examine how serious and widespread the actions at My Lai were conveyed to be, how the circumstances were portrayed, how the actors involved in the incident were characterized, and the extent to which America’s core values were questioned. Our findings suggest that the Nixon administration employed frames designed to downplay the severity of the My Lai incident, highlight extenuating circumstances faced by those directly involved, denigrate the alleged low-level perpetrators, and bolster the national identity. These frames were then largely echoed in the press, despite consistent and forceful challenges by congressional Democrats. These findings, we argue, align with the cascading activation model, and we build on it by highlighting the underlying importance of “cultural resonance” in the framing process. We reflect on the theoretical and practical implications of these patterns and, in doing so, engage the broader scholarly debate over the process through which U.S. news coverage aligns with the communications of government officials, particularly in moments of national dissonance.     

甲状腺滤泡上皮细胞DNA含量与死亡时间的相关性

目的探讨甲状腺滤泡上皮细胞平均DNA含量变化与死亡时间(PMI)的相关性。方法采用甲基绿-派洛宁(MG-P)染色法结合图像分析技术,测定尸体甲状腺滤泡上皮细胞平均DNA含量变化值,并对其数据进行统计学分析。结果甲状腺滤泡上皮细胞平均DNA含量随死后经过时间的延长而加速降解。平均DNA含量各指标(平均灰度、目标面积、目标面积比)与PMI之间的决定系数R2分别为0.960、0.987、0.988和0.990(P<0.001)。结论尸体甲状腺滤泡上皮细胞平均DNA含量与PMI之间具有明显相关性,甲基绿-派洛宁(MG-P)染色法结合图像分析技术测定在研究甲状腺滤泡上皮细胞DNA含量变化方面具有一定优势。