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Since 1995 the Forensic Science Service (FSS) has carried out DNA profiling of reference samples for the UK National DNA Database and in forensic casework using two multiplex STR profiling systems. During this period, profiles with anomalous banding patterns, although comparatively rare, have been encountered regularly. The FSS has collected instances of triallelic patterns and aberrant diallelic patterns. A systematic examination of these patterns has provided insight into their underlying genetic cause. The triallelic patterns could be classified into two types based on the relative intensities of their component alleles. In the Type 1 pattern the alleles were of uneven intensity, whereas in the Type 2 pattern, all three alleles were of even intensity. Evidence is presented that the more frequent Type 1 pattern is the result of somatic mutation at a heterozygous locus, and the Type 2 pattern is the result of a localized chromosomal rearrangement at a heterozygous locus. Directly from the Type 1 pattern, it was possible to deduce the size difference between the progenitor and mutated allele. All mutational changes were found to be multiples of four nucleotides, suggesting the loss or addition of one or more tetrameric repeat units. Aberrant diallelic patterns were identified by analysts due to an unexpectedly large difference in intensity between alleles at a heterozygous locus. While some of these diallelic patterns are likely caused by the same genetic phenomena described above occurring at a homozygous locus, others are demonstrated to be caused by a mutation in the primer binding sequence, leading to a reduction in amplification efficiency of one allele. It is concluded that based on a visual inspection of a profile, it is possible to infer a likely genetic basis directly from the triallelic pattern. By contrast, the aberrant diallelic patterns can be due to any one of a number of possible genetic effects.  相似文献   
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扩增X—Y同源Amelogenin基因内含子在性别鉴定中的应用研究   总被引:2,自引:1,他引:1  
江斌  刘超 《法医学杂志》1997,13(2):68-70
本文用一对针对X-Y同源的Amelogenin基因第一内含子的引物,于同一试管中分别扩增出针对于x和Y染色体的特异性DNA片段:106bp及112bp的PCR产物,经聚丙烯酰胺凝胶电泳后用银染法观察扩增结果,取得了满意的效果.对50pgDNA模板室温放置16年的血痕及单根毛发、烟头等检材均可得到明确的性别鉴定结果.本实验证明该方法简便、灵敏、可靠、特别适用于腐败降解检材的法医学性别鉴定.  相似文献   
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Nearly a decade ago, fentanyl reappeared in the United States illicit drug market. In the years since, overdose deaths have continued to rise as well as the amount of fentanyl seized by law enforcement agencies. Research surrounding fentanyl production has been beneficial to regulatory actions and understanding illicit fentanyl production. In 2017, the Drug Enforcement Administration (DEA) began collecting seized fentanyl samples from throughout the United States to track purity, adulteration trends, and synthetic impurity profiles for intelligence purposes. The appearance of a specific organic impurity, phenethyl-4-anilino-N-phenethylpiperidine (phenethyl-4-ANPP) indicates a shift in fentanyl production from the traditional Siegfried and Janssen routes to the Gupta-patent route. Through a collaboration between the DEA and the US Army's Combat Capabilities Development Command Chemical Biological Center (DEVCOM CBC), the synthesis of fentanyl was investigated via six synthetic routes, and the impurity profiles were compared to those of seized samples. The synthetic impurity phenethyl-4-ANPP was reliably observed in the Gupta-patent route published in 2013, and its structure was confirmed through isolation and structure elucidation. Organic impurity profiling results for illicit fentanyl samples seized in late 2021 have indicated yet another change in processing with the appearance of the impurity ethyl-4-anilino-N-phenethylpiperidine (ethyl-4-ANPP). Through altering reagents traditionally used in the Gupta-patent route, the formation of this impurity was determined to occur through a modification of the route as originally described in the Gupta patent.  相似文献   
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Emerging evidence suggests that perceived injustice is a risk factor for poor recovery outcomes in individuals with whiplash injuries. The present study examined the relative contributions of treatment-related reductions in pain severity, depressive symptoms, and disability in the prediction of reductions in perceived injustice in individuals with whiplash injury. The study sample consisted of 71 individuals (43 women and 28 men) who sustained whiplash injuries in motor vehicle accidents and who were enrolled in a treatment program designed to promote functional recovery following whiplash injury. For the purposes of this study, only individuals who scored above the risk threshold on a measure of perceived injustice were included in the study sample. Participants completed measures of pain severity, disability, depressive symptomatology, and perceived injustice prior to treatment and after treatment. Change scores were computed for study variables. The results revealed that reductions in pain severity and disability were correlated with reductions in perceived injustice. Regression analyses revealed that only reductions in disability contributed significant unique variance to the prediction of reductions in perceived injustice. Clinical and theoretical implications of the present findings are discussed.  相似文献   
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The death of the trade regime   总被引:1,自引:0,他引:1  
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Journal of Indian Philosophy -  相似文献   
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Barbara Ward in her keynote address to the Conference on Exploding Cities, held in Oxford England, made the point that the current problems of the cities can only worsen as the world's population doubles by the year 2000 and the worst hit will be the cities of the developing nations. Between 1950 and 2000 urban populations will rise from 500 million to 1000 million, but the equivalent rise in the 3rd world will be from 500 million to 2200 million. The Conference was more successful in identifying the problems and their causes than in proposing solutions. The inadequacy of urban transport was emphasized repeatedly. Crime emerges as another urban headache. Pollution was another popular theme, and shanties were thoroughly examined. Positive proposals too often took the form of self-evident truths. In all cases the message is clear: the 1st prerequisite to urban planning is central control and, if necessary, public ownership of land. A succession of speakers advocated more self-help for the communities which have emerged on the periphery of so many urban centers. Elizabeth Jelin, from Buenos Aires, argued that these communities -- and shanty towns are the most obvious manifestation -- should no longer be viewed as marginal. They perform essential services, especially in terms of employment, and cannot be moved without severe disruption. Self-help was the beacon held up to delegates, despite the warnings that it would lead to complacency on the part of authorities.  相似文献   
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