脱落毛发及毛干DNA的STR分型研究

目的探讨脱落毛发及毛干细胞核DNA提取、含量和STR分型问题。方法对脱落毛发或毛干进行DNA提取和定量,使用低扩增体系、增加循环次数和多次平行扩增等方法扩增DNA样本,采用叠加比较的方法分析STR分型。结果15cm脱落毛发样品DNA含量大于0．3ng的样品占52．8％,STR分型成功率为55．6％;15cm毛干样品DNA含量大于0．3ng的样品占30．6％,STR分型成功率为25％。结论采用增加循环次数、多次平行扩增等LCN—STR分型方法和Mini—STR试剂盒有助于脱落毛发及毛千的STR基因座分型获得。     

Extended PCR conditions to reduce drop-out frequencies in low template STR typing including unequal mixtures

Forensic laboratories employ various approaches to obtain short tandem repeat (STR) profiles from minimal traces (<100 pg DNA input). Most approaches aim to sensitize DNA profiling by increasing the amplification level by a higher cycle number or enlarging the amount of PCR products analyzed during capillary electrophoresis. These methods have limitations when unequal mixtures are genotyped, since the major component will be over-amplified or over-loaded. This study explores an alternative strategy for improved detection of the minor components in low template (LT) DNA typing that may be better suited for the detection of the minor component in mixtures. The strategy increases the PCR amplification efficiency by extending the primer annealing time several folds. When the AmpF?STR^® Identifiler^® amplification parameters are changed to an annealing time of 20 min during all 28 cycles, the drop-out frequency is reduced for both pristine DNA and single or multiple donor mock case work samples. In addition, increased peak heights and slightly more drop-ins are observed while the heterozygous peak balance remains similar as with the conventional Identifiler protocol. By this extended protocol, full DNA profiles were obtained from only 12 sperm heads (which corresponds to 36 pg of DNA) that were collected by laser micro dissection. Notwithstanding the improved detection, allele drop-outs do persist, albeit in lower frequencies. Thus a LT interpretation strategy such as deducing consensus profiles from multiple independent amplifications is appropriate. The use of extended PCR conditions represents a general approach to improve detection of unequal mixtures as shown using four commercially available kits (AmpF?STR^® Identifiler, SEfiler Plus, NGM and Yfiler). The extended PCR protocol seems to amplify more of the molecules in LT samples during PCR, which results in a lower drop-out frequency.     

浅议我国煤炭行业节能减排

气候的异常、能源的紧缺掀起了低碳经济的浪潮,作为煤炭占能源主导地位的国家,由于高碳的性质,使得我国煤炭行业节能减排的任务繁重,而且现在煤炭行业存在产业整体性差、资源浪费严重、后备资源不足、煤矿规模结构不合理、环境污染严重等一系列问题,为了做好节能减排工作,煤炭行业要从系统节能、资源耦合、企业转型、融资租赁等方面着手,由高碳向低碳转变,促进煤炭行业低碳经济的发展。     

浅析低龄职务犯罪的心理及预防

职务犯罪低龄化现象日趋严重,面对这一现象,学者们习惯于从宏观视角分析其原因及预防措施,而对低龄职务犯罪心理甚少关注。文章在对低龄职务犯罪的概念、特点、危害进行分析后,更加深入地探讨了低龄职务犯罪的几种典型心理,并进一步将整个低龄职务犯罪心理的形成过程动态化,从而尝试性地提出了关于低龄职务犯罪心理预防的几点建议。     

Outcomes in a low secure unit: pre-admission and post-discharge comparisons

Empirical research seldom reports on clinical outcomes within low secure services. By comparing outcome measures prior to admission and following discharge this study aimed to investigate the care pathways of patients admitted to a low secure unit (LSU). The study was conducted in an LSU and consisted of 70 patients (54 male, 16 female). Data were collected retrospectively and analysed in relation to placement security (upon admission and discharge) and admissions to hospital. Results revealed that admissions to hospital and time spent in hospital decreased post-discharge in comparison with pre-admission. Forensic patients were found to have fewer admissions than civil patients prior to LSU admission. Some differences were also observed within gender and Mental Health Act (MHA) section status for placement security. The findings demonstrated that following treatment in a LSU, care pathways may be less restrictive than prior to admission. Further, more robust research on the outcomes of LSUs is required.     

Optimization of the collection and analysis of touch DNA traces

The aim of this work was to optimize a strategy for detection, collection, and analysis of touch DNA traces. 4N6FLOWSwabs™ and cotton swabs were compared by collecting touch DNA traces from glass slides and gun shell casings. Shed cells were visualized using Diamond™ nucleic acid dye and a digital fluorescent microscope. Different collection and extraction methods were tested. Collected samples were amplified with the AmpFlSTR® NGMSElect™ kit and the Precision ID mtDNA Whole Genome Panel.     

负所得税制度对我国低收入者补助的思考

负所得税制度是一项对低收入者提供自动支付的制度。该制度的核心是对穷人进行更有效的帮助,并有利于税收制度与社会福利制度的有机结合。对我国低收入者补助有一定指导作用和现实意义。     

A systematic approach to improve downstream single-cell analysis for the DEPArray™ technology

Most commercially available STR amplification kits have never been fully validated for low template DNA analysis, highlighting the need for testing different PCR kits and conditions for improving single-cell profiling. Here, current strategies rely mainly on adjusting PCR cycle number and analytical threshold settings, with a strong preference for using 30 amplification cycles and thresholds at 30–150 RFU for allele detection. This study aimed to (1) determine appropriate conditions for obtaining informative profiles utilizing a dilution series, and (2) test the outcome on single cells using the DEPArray™ technology. Four routinely applied forensic STR kits were compared by using three different amplification volumes and DNA dilutions down to 3.0 pg, while two well-performing kits were used for single/pooled leucocyte and sperm cell genotyping. Besides reduced costs, the results demonstrate that a 50%–75% PCR volume reduction was beneficial for peak height evaluation. However, this was counteracted by an increased artifact generation in diluted DNA volumes. Regarding profile completeness, the advantage of volume reduction was only prominent in samples processed with Fusion 6C. For single and pooled cells, ESIFast and NGMDetect provided a solid basis for consensus profiling regarding locus failure, although locus dropouts were generally observed as stochastic events. Amplification volume of 12.5 μL was confirmed as appropriate in terms of peak heights and stutter frequencies, with increased stutter peaks being the main artifact in single-cell profiles. Limitations associated with these analyses are discussed, providing a solid foundation for further studies on low template DNA.     

Inferior Vena Cava Tumor Thrombosis Secondary to Metastatic Uterine Cancer: A Rare Cause of Sudden Unexpected Death

Pulmonary tumor thromboembolus (PTTE) secondary to uterine cancer is a rare cause of sudden unexpected deaths in the elderly population. Additionally, tumor extension to the inferior vena cava (IVC) makes it rarer. No such cases have been previously reported in the forensic literature. We report this phenomenon in a previously healthy 70‐year‐old woman with no other known risk factors for the development of deep vein thrombosis. The deceased was found dead while watching television with her relatives. Autopsy examination revealed that her death was attributed to a saddle embolus lodged in the main pulmonary arteries. A uterine tumor was discovered, and microscopic examination revealed low‐grade endometrial stromal sarcoma with angiolymphatic invasion. The tumor cells were also found in the embolus and the remnant thrombosis attached to the inner wall of the IVC. This case demonstrates a sudden unexpected death caused by acute PTTE following seeding of uterine cancer into the IVC and raises awareness of such events.