Quantitative structure–activity relationship (QSAR) methodology in forensic toxicology: Modeling postmortem redistribution of structurally diverse drugs using multivariate statistics

Postmortem redistribution (PMR) constitutes a multifaceted process, which renders the analytical results of drug concentrations inaccurate to be interpreted by forensic toxicologists. The aim of the present study was to evaluate whether quantitative structure–activity relationship (QSAR) methodology could serve as an effective tool to estimate the ability of drugs to redistribute across tissue barriers during postmortem period on the basis of their molecular, physicochemical and structural properties. In this aspect, multivariate data analysis (MVDA) was applied to a set of 77 structurally diverse drugs. PMR data expressed by the central:peripheral concentration ratio (C:P ratio) was taken from the literature. An adequate and robust QSAR model (R² = 0.65, Q² = 0.56, RMSEE = 0.34) was established for 59 (77%) out of 77 drugs. Although the derived QSAR model presented limited applicability, it provided an informative illustration of the contributing molecular, physicochemical and structural properties in PMR process. Drugs with strong basic properties and enhanced molecular size, flexibility, lipophilicity and number of halogens were found to be susceptible to increased PMR. Due to the high complexity of PMR process, further QSAR studies need to focus on structurally related drugs to develop more specific models, which could serve as alternative tools to evaluate PMR for different chemical classes.     

Extraction of high quality DNA from biological materials and calcified tissues

Calcified tissues, such as bone and tooth, and some other sample types, such as those containing adhesive, present a challenge to standard extraction protocols. We have developed a lysis reagent, BTA™ lysis buffer, which is designed for use with PrepFiler™ Kit reagents. The BTA™ lysis buffer disrupts calcified tissue matrices and achieves effective extraction of DNA from pulverized bone and tooth samples. In addition, the BTA™ lysis buffer mildly but efficiently extracts DNA from challenging substrates like tape, chewing gum, and cigarette butts and, as with bone and tooth, DNA from these lysates is purified using established PrepFiler™ reagent extraction protocols.We successfully extracted DNA from powdered human bone samples, chewed gum and smoked cigarettes using BTA™ lysis buffer. Extraction yields for bone, gum and cigarette samples tested were consistent and reproducible. This extraction method efficiently removed potential PCR inhibitors from all samples tested, and C_T values for the internal PCR control of Quantifiler^® Human DNA Quantification Kit were consistent and within the normal range. The DNA extracted from these samples also provided conclusive profiles that were free of PCR artifacts when amplified using the AmpF?STR^® Identifiler^® PCR Amplification Kit. The protocol is easily adapted for automation.     

李大钊早期传播马克思主义的再探讨

五四前后李大钊通过办报办刊、发表论著、组织社团、办学讲课、演讲辩论等方式向中国民众传播了马克思主义。他早年对马克思主义的研究和宣传主要涵盖了四方面内容：揭露了帝国主义的本质,阐述了十月革命的伟大意义;较系统地论述了马克思主义理论的基本内容;正确论述了中国革命的一些基本问题,如革命的步骤、手段、动力等等;号召学生和知识分子走与工农相结合的道路。这些杰出的思想主张形成了他早年的理论特色。当然,李大钊对马克思主义的最初理解也存在着一些不准确之处,这种认识偏差是与当时他所处的环境和背景分不开的。李大钊的可贵之处在于其思想随着社会的进步不断发展,并及时将先进的科学理论运用于中国社会变革的实践。     

暴力犯罪后“捎带财物行为”的定性及理性分析

行为人在实施侵犯人身暴力犯罪后“捎带财物行为”的定性,应当具体分析暴力犯罪后“捎带财物行为”性质,即判断先前侵犯人身的暴力犯罪给被害人造成的状态,接着判断先前暴力行为是否形成新的“威胁”以及是否被“捎带财物行为”实施时所利用,最终作出合理的结论。     

中部地区某县104起投毒案件分析

通过对104起投毒案件分析,发现投毒杀人仍是投毒犯罪的一个主要目的;投毒案件既有一定的季节性也表现出一定的地域性;所投毒物种类分布较广,但农药和鼠药占多数;所投毒物具有鲜明的时代性;投毒位置、对象和手段有一定的选择性等规律。     

农村社区警务建设存在的问题及对策分析

农村社区警务的实施对于建设社会主义新农村,保证全社会的安定有序有着重要的意义。但现在农村社区警务存在着很多问题：一是部分民警对社区警务工作重视不够：二是公安机关用于农村社区警务的经费和警力保障不足;三是警民关系不够和谐,农村社区警务工作没有形成警民合力。因此,农村社区警务建设的重点是：一、完善法律法规;二、警力资源的科学配置;三、民警素质的有效增强。     

行政许可程序的立法欠缺及其完善

行政许可程序是规范行政许可的行为,防止行政许可实施权的滥用,保障公民、组织在行政许可实施中的正当权利的重要环节。尽管行政许可法设计了许多程序规则,但在某些方面还存在问题,诸如处理期限的规定不完善、听证程序不健全、缺乏有效的保障制度等。笔者在对此分析研究的基础上,提出了一些健全和完善我国行政许可程序的设想和建议。     

对实用艺术作品著作权保护之法律探析——完善我国《著作权法》立法建议

我国《著作权法》及《著作权法实施条例》中,对实用艺术作品均没有任何明确的规定,实用艺术作品的法律保护至今仍为空白。我国应结合国际公约、条约和国外一些国家的法律规定,在《著作权法》中应明确规定对实用艺术作品的著作权保护的具体措施。