聚合酶链反应检测绵羊肺炎霉形体的研究

参照基因库中已发表的绵羊肺炎霉形体Y98株的 1 6SrDNA序列 ,设计合成了 1对引物 ,建立了聚合酶链反应 (PCR)检测绵羊肺炎霉形体的方法。结果显示 ,所建立的PCR能特异扩增绵羊肺炎霉形体的DNA ,而对照的菌株均为阴性 ;其敏感性可达 1pg。经对绵羊肺炎霉形体分离株HD 1的扩增产物进行测序 ,并与绵羊肺炎霉形体标准株Y98的 1 6SrDNA序列进行比较 ,发现有 6个碱基的差异     

Powdered Activated Carbon: An Alternative Approach to Genomic DNA Purification

Forensic evidence samples are routinely found as stains on various substrates, which may contain substances known to inhibit polymerase chain reaction (PCR). The goal of this study was to evaluate post‐Chelex^®100 purification using powdered activated carbon (PAC). Mock crime scene DNA extracts were analyzed using quantitative PCR and short tandem repeat (STR) profiling to test the DNA recovery and inhibitor removal using PAC with those of the Amicon^®Ultra 100K. For extracted bloodstains on soil and wood substrates, PAC and Amicon^®Ultra 100K generated similar DNA yield and quality. Moreover, the two methods significantly decreased the concentration of humic substances and tannins compared to nonpurified extracts (p < 0.001). In instances where extracts contained indigo dye (bloodstains on denim), Amicon^®Ultra 100K performed better than PAC due to improved amplifiability. Efficient adsorption of humic substances and tannins, which are common inhibitors, indicates PAC's potential application in the purification of high‐template DNA extracts.     

Forensic Potential of MMPs and CC Chemokines for Wound Age Determination

In this study, we investigated time-dependent expression of matrix metalloproteases (MMP)-2, MMP-9, chemokine CC motif ligand (CCL)-2, CCL-3, CCL-5, IL-1β, IL-6, and TNF-α mRNA at the skin injury site and sought their forensic potentials during the skin wound repair process. The tested wound ages in 42 mouse skin wounds were distributed at 0d, 1d, 3d, 5d, 7d, 10d, and 14d, respectively and then followed by real-time polymerase chain reaction. Ultimately, MMP-2 played an important role in the inflammation phase. On the contrary, MMP-9 became involved at a later phase during wound healing. Meanwhile, CCL-2 and CCL-3 were active throughout almost all of the process. However, CCL-5 mRNA had no significance. Collectively, an MMP-9/MMP-2 ratio of over 0.84 indicated that skin wound healing age was strongly 5 days or less. So elevated gene expressions of cytokines and chemokines in different phases of wound ages implied that combined exploration could make wound age determination more accurate and objective.     

ABO位点限制性扩增片段长度多态性的研究

建立了PCR扩增、限制性酶切、8％（T）、5％（C）聚丙烯酸胺凝胶垂直电泳和银染检测ABO位点的限制性片段长度多态性的方法体系。应用Amp-RFLP技术对185名中国人（哈尔滨）ABO位点的基因频率和基因型分布进行了调查和统计分析。ABO位点特异片段长度为140～200bp，基因频率为0．2000～0．5568。6种基因型频率为0．973～0．3135，杂合度0．5838，Dp值0．7146。经H－W平衡吻合度检测，完全符合群体遗传多态分布。通过对11个家庭33名相关个体的分析，证明完全符合孟德尔遗传定律。ABO基因型检验适用于法庭科学的个体识别和亲权鉴定。     

“三队一室”运作模式的警务价值评析

公安派出所工作是公安基层基础建设中最重要的一环。派出所“三队一室”警务模式改革,着力解决长期困扰基层派出所工作运行中的警力难以下沉、机构设置不合理、职能分配不明确、勤务效率不高、防范不到位、打击不及时等突出问题,保证了基层基础工作在“大防范”中基础性、先导性的战略地位,有利于实现统一、高效、完整的现代警务运行机制。     

河南汉族群体6个STR基因座遗传多态性研究

目的　通过研究 6个STR基因座FGA ,TPOX ,D3S135 8,vWA ,D8S1179,D2 1S11的遗传多态性 ,了解它们在河南汉族人群中的多态分布 ,与其他群体进行比较 ,得出遗传距离 ,并了解它在法医学中的应用价值。　方法　采用多聚酶链式反应扩增这 6个基因座 ,采用非变性聚丙烯酰氨凝胶电泳银染显色分析。　结果　得出这 6个基因座在河南汉族人群中的基因频率 ,并计算得出杂合度、个体识别率、非父排除率 ,与其他群体比较得出进化距离。　结论　这 6个基因座有较高的杂合度 ,并且具有相对遗传稳定性 ,在人群中的分布符合Hardy -Weinberge平衡 ,有较高的法医学价值 ,可以应用于个体识别和亲权鉴定。     

Screening Test for Shed Skin Cells by Measuring the Ratio of Human DNA to Staphylococcus epidermidis DNA

A novel screening method for shed skin cells by detecting Staphylococcus epidermidis (S. epidermidis), which is a resident bacterium on skin, was developed. Staphylococcus epidermidis was detected using real‐time PCR. Staphylococcus epidermidis was detected in all 20 human skin surface samples. Although not present in blood and urine samples, S. epidermidis was detected in 6 of 20 saliva samples, and 5 of 18 semen samples. The ratio of human DNA to S. epidermidisDNA was significantly smaller in human skin surface samples than in saliva and semen samples in which S. epidermidis was detected. Therefore, although skin cells could not be identified by detecting only S. epidermidis, they could be distinguished by measuring the S. epidermidis to human DNA ratio. This method could be applied to casework touch samples, which suggests that it is useful for screening whether skin cells and human DNA are present on potential evidentiary touch samples.     

Application of mRNA Expression Analysis to Human Blood Identification in Degenerated Samples that were False‐negative by Immunochromatography,,

Forensic laboratories are often faced with cases in which methamphetamine hydrochloride‐mixed blood is unable to be identified as human blood by immunochromatography against human hemoglobin A0. The application of mRNA expression analysis to samples that showed a false‐negative with immunochromatography was investigated as an alternative approach that did not depend on the antigen–antibody reaction. Real‐time PCR was used to examine the expression levels of blood markers such as glycophorin A, spectrin beta, and hemoglobin beta. Hemoglobin beta was the only marker that was specifically detected in blood, while glycophorin A was useful for determining human specificity. Hemoglobin beta showed good detection sensitivity and was detectable in 37‐year‐old blood stains. Hemoglobin beta was exclusively detectable in methamphetamine hydrochloride‐mixed blood stains. Detergents and disinfectants did not significantly influence mRNA markers. The proposed mRNA expression analysis was suitable for human blood identification as an alternative method to immunochromatography.     

Supervision Intensity and Parole Outcomes: A Competing Risks Approach to Criminal and Technical Parole Violations

Recent scholarship about parole supervision indicates that higher supervision intensity is associated with an increased risk of parole violations. However, parole violations can take many forms—some minor and some serious—and theory suggests that supervision intensity might have differential effects depending upon the type of violation. We use “competing risks” survival models to identify supervision effects on five types of parole violations among 79,082 individuals released from prison in California: absconding, technical violations, drug use, violent offenses, and sexual offenses. We find that supervision effects are strongest for absconding violations. Past sexual offending also triggers significant supervision effects for technical violations, drug use violations, and violent violations. We conclude that parole violation patterns are influenced by parolee behaviors, the amount of attention the state is paying to those behaviors, and official markers of criminal dangerousness that are attached to particular parolees.     

Students’ foundational understanding of chemical reaction in the forensic science bachelor’s degree program at the National Autonomous University of Mexico

ObjectiveTo compare the understanding of the concept of chemical reaction—as operationalized by Bloom’s taxonomy of cognitive levels—of students in forensic science bachelor’s degree with that achieved by students majoring in chemistry, as a prerequisite for future professional collaboration and communication.Materials and methodsUsing previously validated and published tests developed to assess students’ knowledge, comprehension, and application of the concept of chemical reaction, we explored how conceptual understanding developed in students enrolled in (a) a forensic science degree program in a Mexican public university and in (b) chemistry undergraduate programs offered by the same university, and whether both groups achieved comparable attainment levels.Findings and implicationsDespite receiving considerably less chemical instruction, forensic science students achieved comparable levels of conceptual understanding of chemical reaction to those exhibited by chemistry students. This finding is encouraging because it might mean that future forensic scientists could graduate with a solid foundation of chemical knowledge. More research, particularly on the learning of other key concepts, will be needed to verify these initial findings.