Population data on the forensic genetic markers: phosphoglucomutase-1, esterase D, erythrocyte acid phosphatase and glyoxylase I

Blood specimens from white and black sample populations from Baltimore, Maryland, were analyzed for the four most forensically important, polymorphic red cell enzyme systems-phosphoglucomutase-1, esterase D, erythrocyte acid phosphatase and glyoxalase I. The distributions of the phenotypes for each marker in each racial group were in Hardy-Weinberg equilibrium. The population data were similar to previously reported data for Whites and Blacks from different geographical locations within the United States.     

Acid alteration of several ignitable liquids of potential use in arsons

Ignitable liquids such as fuels, alcohols and thinners can be used in criminal activities, for instance arsons. Forensic experts require to know their chemical compositions, as well as to understand how different modification effects could impact them, in order to detect, classify and identify them properly in fire debris. The acid alteration/acidification of ignitable liquids is a modification effect that sharply alters the chemical composition, for example, of gasoline and diesel fuel, interfering in the forensic analysis and result interpretation. However, to date there is little information about the consequences of this effect over other accelerants of interests. In this research paper, the alteration by sulfuric acid of several commercial thinners and other accelerants of potential use in arsons is studied in-depth. For that purpose, spectral (by ATR-FTIR) and chromatographic (by GC–MS) data were obtained from neat and acidified samples. Then, the spectral and chromatographic modifications of each studied ignitable liquid were discussed, proposing several chemical mechanisms that explain the new by-products produced and the gradual disappearance of the initial compounds. Hydrolysis, Fischer esterification and alkylation reactions are involved in the modification of esters, alcohols, ketones and aromatic compounds of the studied ignitable liquids. This information could be crucial for correctly identifying these accelerants. Additionally, an exploratory analysis revealed that some of the most altered ignitable liquid samples might be very similar with each other, which could have impact on casework.     

生物检材中微量斑蝥素的检验

本文提出了用酸解法分离提取生物检材中的斑蝥素,并提供了一种新的薄层显色方法。以烯丙异丙巴比妥为内标的气相色谱法测定斑蝥素含量,准确可靠。回收率可达85％。应用该法测定了中毒动物死后的体内分布。     

The effect of corrosive substances on fingermark recovery: A pilot study

Corrosive substance attacks have become a growing issue within the UK. Although most commonly occurring in gang-related offences, there are high profile instances where this type of attack has been used to attack women to disfigure and destroy livelihoods. Despite the increase in such attacks, there has been very little published research into the recovery of forensic evidence from items used in these crimes. The effect of corrosive substances on the recovery of different types of forensic evidence is unknown, and there is no guidance for laboratories processing exhibits contaminated with corrosive substances regarding optimum treatments. This pilot study focused on establishing the effectiveness of a range of fingermark visualisation processes in recovering fingermarks on surfaces exposed to concentrated sulfuric acid (acid) and potassium hydroxide (alkali). Results indicate that on non-porous surfaces vacuum metal deposition and powder suspensions remain effective, and on porous surfaces fingermarks could still be visualised with physical developer. Alkalis were found to be more detrimental than acid environments in this limited study. The results demonstrate that fingermark recovery is still feasible on surfaces exposed to corrosive substances and provides encouragement that treatment protocols could be developed for this type of exhibit.     

酸性染料比色法测定宁心滴丸的含量

目的：采用酸性染料比色法测定宁心滴丸中的环维黄杨星D。方法：于410nm波长处检测显色后的氯仿提取液。结果：环维黄杨星D在0．9896－7．4420μg/ml范围内的直线回归方程为A＝0．04813＋0．06432C，相关系数γ＝0．9997，回收率为100．0％，RSD＝1．7％。结论：该方法简便、准确、无干扰，可用于宁心滴丸的质量控制。     

脑死亡后神经细胞溶酶体酸性磷酸酶变化的研究

在颅内高压致脑死亡动物模型基础上采用酶细胞化学技术对脑死后不同水平神经细胞溶酶体酸性磷酸酶(AcidPhosphatase,ACP)活性变化和定位分布作了同步观察.结果显示,脑死亡后神经细胞ACP活性先增高,继而逐渐降低乃至消失,以大脑和小脑神经细胞为著;脑干神经细胞ACP一直保持较高活性;脑死亡9h内ACP定位无改变.表明神经元ACP活性改变可能是脑死亡神经病理学变化的发病机制之一.     

吉林地区朝鲜族唾液酸性富含脯氨酸蛋白遗传多态性的研究

应用聚丙烯酸胺凝胶等电聚焦技术，调查了吉林地区226名朝鲜族个体唾液酸性富含脯氨酸蛋白二位点上共6种等位基因频率的分布：PRH1*1为0．0331，PRH1*2为0．2124，PRH1*4为0．7477，PRH1*6为0．0068；PRH2*1为0．7544，PRH2*2为0．2456。按Hardy－Weinberg法则进行吻合度检验，其观察值和期望值一致，并对吉林地区朝鲜族与其它地区人群酸性富含脯氨酸蛋白等位基因的差异性做了比较。PRH1和PRH2在吉林延边地区朝鲜族的个人识别能力分别为0.58和0．53，两者总鉴别机率为0．80；PRH1和PRH2的非父排除率为0．1875和0．1510，两者总非父排除率为0．3102。     

The use of isoelectric focusing (IEF) as a method for the combined phenotyping of erythrocyte acid phosphatase (EAP) and esterase D (EsD)

The simultaneous isoelectric focusing (IEF) in polyacrylamide gels (PAG) of erythrocyte acid phosphatase (EAP) and esterase D (EsD) allows the poor discriminating power (DP) of EsD to be usefully combined with a highly discriminating system EAP, such that a joint DP of 0.766 was achieved compared with PGM IEF DP 0.756. Focusing was carried out in a centrally flattened gradient containing ampholines (pH 4-6 and 6-8) and the chemical spacer 3-(N-morpholino) propanesulphinic acid (MOPS). It enabled the identification of six EsD phenotypes including the recently discovered EsD5 isozymes. The application of this method to casework bloodstains is discussed.     

Biological and DNA evidence in 1000 sexual assault cases

Using a Filemaker-based database (DNA Pro-FILES, Synchrone Infosystème Inc.), we have conducted a large-scale study on 1000 sexual assault (SA) cases where a standardized kit was submitted to our laboratory alone or with other types of exhibits. We looked at the likelihood of obtaining good quality DNA evidence, allegedly from the assailant, according to a number of parameters.The overall proportion of SA cases with DNA evidence is nearly 50%. A little more than 30% of SA kits provided DNA evidence while for 16% of cases DNA evidence could be obtained only from other exhibits.The likelihood of obtaining DNA evidence is approximately 50% in teenager and adult SA cases, but much lower for children 10 years old or younger (15%). In children cases, profiles were found mostly on clothing or skin swabs.The likelihood of obtaining DNA evidence from vaginal swabs remains good for up to 3 days after the assault (from 35% on the first day to 23% on the third day). A DNA profile was obtained from approximately 22% of anal/rectal swabs and 41% of skin swabs taken less than 1 day after the assault. Less than 10% of oral washes provided DNA evidence, all having been collected within 24 h of the assault.We found that in bodily samples, a negative result for acid phosphate (AP) is a poor predictor of the likelihood of obtaining good quality DNA evidence. Approximately 15% of vaginal swabs and 8% of anal swabs negative for AP nevertheless provided good quality DNA evidence.     

The use of Polilight in the detection of seminal fluid, saliva, and bloodstains and comparison with conventional chemical-based screening tests

Biological stains can be difficult to detect at crime scenes or on items recovered from crime scenes. The use of a versatile light source may assist in their detection. The ability of Polilight to locate potential semen, saliva, and blood stains on a range of substrates and at different dilutions was tested. We also tested the use of Polilight in comparison with conventional chemical-based presumptive screening tests such as acid phosphatase (AP), Phadebas, and luminol, often used in casework for detecting potential semen, saliva, and blood stains, respectively. The Polilight was able to locate stains that were not apparent to the naked eye. The color of the material on which a stain is deposited can have an effect on the detectibility of the stain. The Polilight was found to be comparable with the AP and Phadebas tests in terms of its sensitivity. In a comparative study between the AP test and Polilight on 40 casework exhibits, one false-negative result was observed when using the Polilight. On a series of mock casework exhibits it was determined that the Polilight can be used successfully to locate saliva stains for DNA analysis. The sensitivity of luminol for detecting potential bloodstains was greater than that of Polilight; however the Polilight has particular application in instances where a bloodstain may have been concealed with paint. Overall, the Polilight is a relatively safe, simple, noninvasive, and nondestructive technique suitable for use in forensic casework.