Molecular Identification of Three Indian Snake Species Using Simple PCR–RFLP Method*

Abstract: Three endangered Indian snake species, Python molurus, Naja naja, and Xenochrophis piscator are known to be significantly involved in illegal trade. Effective authentication of species is required to curb this illegal trade. In the absence of morphological features, molecular identification techniques hold promise to address the issue of species identification. We present an effective PCR–restriction fragment length polymorphism method for easy identification of the three endangered snake species, Python molurus, Naja naja, and Xenochrophis piscator. A 431‐bp amplicon from cytochrome b gene was amplified using novel snake‐specific primers following restriction digestion with enzymes Mbo II and Fok I. The species‐specific reference fragment patterns were obtained for the target species, which enabled successful identification of even highly degraded shed skin sample confirming the utility of the technique in case of poor‐quality DNA. The assay could be effectively used for forensic authentication of three Indian snake species and would help strengthen conservation efforts.     

Digital Stratigraphy: Contextual Analysis of File System Traces in Forensic Science

This work introduces novel methods for conducting forensic analysis of file allocation traces, collectively called digital stratigraphy. These in‐depth forensic analysis methods can provide insight into the origin, composition, distribution, and time frame of strata within storage media. Using case examples and empirical studies, this paper illuminates the successes, challenges, and limitations of digital stratigraphy. This study also shows how understanding file allocation methods can provide insight into concealment activities and how real‐world computer usage can complicate digital stratigraphy. Furthermore, this work explains how forensic analysts have misinterpreted traces of normal file system behavior as indications of concealment activities. This work raises awareness of the value of taking the overall context into account when analyzing file system traces. This work calls for further research in this area and for forensic tools to provide necessary information for such contextual analysis, such as highlighting mass deletion, mass copying, and potential backdating.     

关于构建大学英语课互动教学模式的思考

互动教学法是一种富有创意和实效的现代教学理论和教学策略。在大学英语教学中引入互动教学模式,把握互动教学法的基本特征和原则,确立师生双方主体地位,调动师生在教和学中的积极性和创造性,有助于教学相长和教学质量的提高。     

复合扩增STR位点片段长度多态性的研究

本文介绍了以三个短串联重复序列（STR）位点为基础的复合扩增进行个体识别的技术。其特点是在同一扩增体系内对彼此独立的三个STR位点，即HUMTH01[AATG]nHUMFABP[AAT]nHUMARA[AGC]n进行复会扩增，扩增产物用聚丙烯酰胺凝胶电泳分离。经研究发现这三个STR位点具有高度多态性，扩增产物分子量在190～310bP之间，各位点等位基因数分别为6、9、16个，杂合度78．2％、85，0％、89．0％，个体识别率0．918、0．960、0．905，其累积的个体识别率达0．9997，高于pMCT118等位点，且扩增时间短，操作简便，为法医物证检验提供了一种高效的个体识别手段。     

多囊卵巢综合征体质指数、性激素及胰岛素抵抗水平与中医证型相关性研究

目的 探讨多囊卵巢综合征（polycystic ovary syndrome,PCOS）患者的体质指数、性激素和胰岛素水平与中医证型的相关性。方法 选择91例PCOS患者（肝经湿热型50例、痰湿阻滞型41例）,观察并比较两种证型患者的人体测量学指标、性激素及空腹血糖(fasting plasma glucose,FPG)、空腹胰岛素(fasting insulin,FINS)、稳态模型胰岛素抵抗指数(homeostasis model assessment of insulin resistance,HOMA-IR)水平。结果 痰湿阻滞型患者的体质指数(body mass index,BMI)、腰臀比（waist-to-hip ratio,WHpR）、腰身比（waist-height ratio,WHtR）均明显高于肝经湿热型患者（P<0.05）;痰湿阻滞型患者FPG、FINS、HOMA-IR水平均明显高于肝经湿热型患者（P<0.05）;肝经湿热型患者黄体生成激素(luteinizing hormone,LH)、卵泡刺激素(follicle stimulating hormone,FSH)水平明显高于痰湿阻滞型患者（P<0.05）。结论 PCOS痰湿阻滞型患者BMI、WHpR、WHtP等人体测量学指标和FPG、FINS、HOMA-IR水平明显高于肝经湿热型患者,LH、FSH水平明显低于肝经湿热型患者。     

Testing Anatomical Methods for Stature Estimation on Individuals from the W. M. Bass Donated Skeletal Collection

Abstract:  This study compared eight versions of the anatomical method for stature estimation on a white male sample ( n  = 34) from the W. M. Bass Donated Skeletal Collection. The aim was to evaluate errors in the estimates and to discuss how useful the methods are in forensic context. The average error estimating living stature was less than 1 cm for six of the methods. The correlations between the estimates were high ( r  = 0.982–0.999). In practice, differences between the versions as well as those between long bone-based equations and anatomical methods were small. Anatomical method is nevertheless more accurate than long bone regressions when individuals with atypical body proportions are examined.     

Recovery and STR amplification of DNA from RFLP membranes

Restriction fragment length polymorphism (RFLP) techniques were utilized in the forensic DNA community until the mid 1990s when less labor-intensive polymerase chain reaction short tandem repeat (PCR STR) techniques became available. During the transition from RFLP technology to PCR-based STR platforms, a method for comparing RFLP profiles to STR profiles was not developed. While the preferred approach for applying new technology to old cases would be to analyze the original biological stain, this is not always possible. For unsolved cases that previously underwent RFLP analysis, the only DNA remaining may be restriction cut and bound to nylon membranes. These studies investigate several methods for obtaining STR profiles from membrane bound DNA, including removal of bound DNA with bases, acids, detergents, various chemicals, and conventional cell extraction solutions. Direct multiplex STR amplification of template in the membrane-bound state was also explored. A partial STR profile was obtained from DNA that was recovered from an archived membrane using conventional extraction buffer components, indicating promise for recovering useful STR information from RFLP membranes that have been maintained in long-term frozen storage.     

Spatial and temporal influences on bacterial profiling of forensic soil samples

Bacterial content may be helpful in differentiating forensic soil samples; however, the effectiveness of bacterial profiling depends on several factors, including uniqueness among different habitat types, the level of heterogeneity within a habitat, and changes in bacterial communities over time. To examine these, soils from five diverse habitats were tested over a 1 year period using terminal restriction fragment length polymorphism (TRFLP) analysis. Soil samples were collected at central locations monthly, and 10 feet in cardinal directions quarterly. Similarity indices were found to be least related among habitats, while the greatest bacterial similarities existed among collection locations within a habitat. Temporally, however, bacterial content varied considerably, and there was substantial overlap in similarity indices among habitats during different parts of the year. Taken together, the results indicate that while bacterial DNA profiling may be useful for forensic soil analysis, certain variables, particularly time, must be considered.