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排序方式: 共有684条查询结果,搜索用时 15 毫秒
681.
目的 探讨大豆异黄酮(soybean isoflavones,SIF)改善阿尔茨海默病(Alzheimer''s disease,AD)大鼠学习记忆能力的机制。方法 将70只大鼠随机分为正常对照组,假手术组,模型组,雌激素组和高、中、低剂量SIF治疗组,采用右侧杏仁核注射β-淀粉样肽(β-amyloid peptide,Aβ)25-35复制AD大鼠模型,给予不同剂量的SIF,通过检测逃避潜伏期、游泳时间百分比和2 min内穿过平台次数评价大鼠学习记忆能力,观察并比较各组大鼠海马胆碱乙酰转移酶(choline acetyltransferase,ChAT)活性和半胱天冬氨酸特异性蛋白酶3(cysteinyl aspartate specific protease-3,caspase-3)的活性。结果 与模型组比较,高、中、低剂量SIF组逃避潜伏期显著降低(P<0.01),游泳时间百分比和穿过平台次数显著增加(P<0.01),高、中剂量SIF组大鼠海马ChAT活性显著升高(P<0.01),各剂量SIF组AD大鼠海马caspase-3活性显著降低(P<0.01)。高、低剂量SIF组逃避潜伏期、2 min内穿过平台次数、ChAT活性和caspase-3活性比较,差异具有统计学意义(P<0.01)。结论 大豆异黄酮通过调节AD大鼠海马ChAT和caspase-3活性,改善其学习记忆能力,并呈现一定的量效关系。 相似文献
682.
《Science & justice》2023,63(4):456-467
Photometric Stereo and Elastomeric Sensor Imaging were assessed for measuring the 3-dimensional (3D) morphology of questioned document samples. Photometric stereo is shown to be a powerful non-contact technique for revealing micron level detail of the samples examined. Elastomeric Sensor Imaging is shown to complement photometric stereo by yielding equivalent results. Additionally, this technique allows quantification of the morphological depth information. The techniques were applied to 2 different types of questioned document sample. Firstly, written signatures were examined. Both techniques were able to reveal characteristic features that could be used to infer stroke direction and ink line application sequence. Secondly toner/ink intersections were examined. Both techniques allowed visualisation of 3D features which were used to infer the sequence of application. 相似文献
683.
《Science & justice》2023,63(4):542-550
Firearms identification has an important place in forensic ballistic investigations since the weapons are widely used in criminal offences. Firearm examiners resolve many case files, through the use of automatic systems or comparison microscopes. Advanced forensic technologies like BALİSTİKA helps to record and analyze non standard ballistic evidence. In today's world, with the ease of access to materials and production technique information, pistols modified from blank firers are frequently encountered as crime tools. In this study, the characteristics of 7.65 mm fired cartridge cases obtained by controlled shots from blank firing modified pistols were examined, and their detection performances were compared by means of the Balistika system. Although distinctive differences are not expected after successive test shootings, balistically important changes were seen after the use of blank firing modified pistols and the 3D imaging system proved to be useful in observing such differences. The analyses showed that the modifications in weapons lead to variation in the ballistic characteristics and reduce the accuracy of the detection performance, which may result in flawed forensic decisions. It was also found that the deviations in ballistic impressions of modified blank firing pistols were greater than that of standard fabricated and hand-made pistols. This unique study contributed to the forensic sciences literature by focusing on the impact of modified weapons on ballistic characteristics. 相似文献
684.
《Science & justice》2023,63(3):303-312
Following decomposition of a human body, a variety of decomposition products, such as lipids, are released into the surrounding environment, e.g. soils. The long-lasting preservation in soils and their high diagnostic potential have been neglected in forensic research. Furthermore, little is known about the preservation, chemical transformation, or degradation of those human derived lipids in soils. To date, several studies identified various lipids such as long-chain free fatty acids and steroids in soils that contained decomposition fluids. Those lipids are preserved in soils over time and could serve as markers of human decomposition in forensic investigations, e.g. for estimating the post-mortem interval or identifying the burial location of a human body. Therefore, this review focuses on the current literature regarding fatty acid and steroid that have been detected in soils and associated with human body decomposition. After a short introduction about human decomposition processes, this review summarises fatty acid and steroid analysis applied in current case studies and studies related to taphonomic research. This review provides an overview of the available studies that have used fatty acids and steroids as identifiers of human decomposition fluid in soils in a forensic context and discusses the potential for developing this innovative field of research with direct application in a forensic context. 相似文献