Comparative and Correlation Studies of Biochemical Substances in Vitreous Humor and Synovial Fluid

Vitreous humor (VH) and synovial fluid (SF) become optional postmortem samples for biochemistry investigation. However, few studies have explored SF as a potential source, and there is still controversy whether the biochemical concentrations in bilateral VH are the same. We explored the concentrations of biochemical substances in both VH and SF, and compared between both sides and between the fluids. We also correlated the biochemical concentrations in both fluids. All samples were centrifuged after collection and the supernatant fluids were used for the analysis. The results indicated no significant difference in the constituent concentrations between the fluids from both sides (p > 0.05). Sodium, potassium, chloride, and magnesium concentrations were significantly higher in the VH, but in vice versa for glucose, uric acid, and creatinine concentrations (p < 0.001). Sodium, potassium, glucose, lactate, urea, uric acid, and creatinine concentrations between both fluids showed significant correlation (p < 0.05), but not chloride and magnesium concentrations.     

眼损伤图形刺激对比度视诱发电位

目的研究眼损伤者对比度视诱发电位的特征。方法选取本中心行法医临床学鉴定的60例眼损伤者,根据最佳矫正视力分为0.2~0.3(A组)、0.3~0.5(B组)、≥0.5(C组)三组。分别观察100%、25%、10%对比度条件下的对比度视诱发电位波的振幅及潜伏期变化特征,并行统计学分析。结果 (1)相同对比度时,P_(100)波振幅随刺激视角的减小而降低;(2)相同刺激视角时,P_(100)波振幅随对比度降低而降低,组间差异有统计学意义(P0.05);(3)100%、25%对比度时,相同刺激视角(100%7′视角除外),A组与B组差异无统计学意义(P0.05);A组与C组、B组与C组随视力提高,P_(100)波振幅增高(P0.05);10%对比度15′刺激视角,P_(100)波振幅随视力提高而增高(P0.05);(4)相同对比度下,相同刺激视角时,P_(100)波潜伏期随视力提高而缩短,但组间差异无统计学意义(P0.05)。相同刺激视角时,随对比度降低,P_(100)波潜伏期延长,但差异无统计学意义(P0.05)。结论对比度视诱发电位有望成为评估对比度视力的方法之一。     

眼动追踪技术及其在侦查辨认中的应用

辨认,从心理学角度来讲,是感知、记忆、再认的过程。通过眼动追踪技术可以实时采集辨认人在辨认过程中的眼动数据,了解其在辨认中是如何思考及做出辨认结果的心理认知过程。利用眼动追踪技术,分析证人、犯罪嫌疑人辨认过程中的眼动模式,有助于研究证人辨认的准确率、识别犯罪嫌疑人、辅助发现破案线索等问题。眼动追踪技术在侦查辨认领域有广阔的应用前景。     

眼动追踪技术的基本原理及其在侦查辨认中的应用前景

辨认从心理学角度来讲是感知、记忆、再认的过程。通过眼动追踪技术可以实时采集辨认人在辨认过程中的眼动数据,了解其在辨认中的是如何思考及做出辨认结果的心理认知过程。利用眼动追踪技术,分析证人、犯罪嫌疑人辨认过程中的眼动模式,有助于研究证人辨认的准确率、识别犯罪嫌疑人、辅助发现破案线索等问题,在侦查辨认领域有广阔的应用前景。     

Pig-mentation: postmortem iris color change in the eyes of Sus scrofa

Experienced forensic pathologists and examiners may be familiar with the phenomenon of postmortem iris color change; however, only Knight, Simpson's forensic medicine, Arnold, London, 1997; Ref. 1 and Saukko and Knight, Knight's forensic pathology, 3rd ed., Arnold, London, 2004; Ref. 2 have referred to it in the literature, and to date, there have been no published scientific research studies on this taphonomic artifact. A controlled experiment was conducted of postmortem changes to isolated Sus scrofa eyes. The eyes (n = 137) were separated into three groups and each sample was observed for 3-day postmortem at a different temperature. In addition, a Sus scrofa head was obtained to observe postmortem changes of eyes in situ. All isolated blue eyes in the experiment, at room temperature and higher, changed to brown/black within 48 h. The in situ blue eye, at room temperature, turned brown/black within 72 h. If iris color consistently changes postmortem in humans, then this taphonomic artifact must be incorporated into victim identification protocol, including disaster victim identification software, and autopsy reports to prevent inaccurate victim identification and inappropriate exclusion from the identification process.     

眼动追踪仪在测谎中的应用

目的探究眼动追踪在测谎中的应用价值。方法使用随机数字法将40名被试分为两组,实验组在实施模拟犯罪后利用眼动追踪仪记录其在观察靶刺激和非靶刺激时的瞳孔直径、注视时间、注视点和眨眼次数,对照组直接采集眼动数据。采用t检验分析实验组和对照组在观察靶刺激与非靶刺激时眼球运动参数的差异,用Pearson相关系数分析存在差异的眼球运动参数之间的相关性,用受试者操作特征(receiver operator characteristic,ROC)曲线估计眼球运动参数甄别实验组与对照组的有效性。结果实验组观察靶刺激与非靶刺激时相比,平均瞳孔直径减小、注视时间延长、注视点减少(P<0.05),但眨眼次数的差异无统计学意义。对照组在观察靶刺激和非靶刺激时上述指标的差异均无统计学意义。实验组平均注视时间与注视点呈负相关(r=-0.255,P<0.05),平均注视时间与平均瞳孔直径之间呈负相关(r=-0.218,P<0.05),注视点与平均瞳孔直径之间呈正相关(r=0.09,P<0.05)。平均瞳孔直径、平均注视时间和注视点的曲线下面积分别为0.603、0.621和0.580。结论眼动追踪仪所测得的平均瞳孔直径、平均注视时间和注视点在实验室条件下可以用于测谎。     

The genetics of eye colours in an Italian population measured with an objective method for eye colour quantification

Brown and blue eye colours are primarily explained by the single nucleotide polymorphism (SNP) HERC2 rs12913832. However, the genetics of eye colours that appear to be neither blue nor brown are not well understood. In this study, 230 unrelated Italian individuals were typed for 32 SNP loci in pigmentary genes. High resolution digital images of the participants’ eyes were taken and the iris region was successfully extracted with the use of the custom designed software Digital Iris Analysis Tool (DIAT) from 218 of the 230 (95%) images. The software counted the numbers of blue and brown pixels in the iris region and calculated a Pixel Index of the Eye (PIE-score) that described the eye colours quantitatively. The PIE-score ranged from −1 to 1 (brown to blue). We investigated the association of the PIE-scores extracted from the eye images with the genotypes of the 32 pigmentary SNPs. We observed a statistically significant association between the PIE-scores and the SNP loci rs12913832, rs4778241, rs7495174 in the HERC2/OCA2 region and the locus rs16891982 in SLC45A2.     

Visual attention and expertise for forensic signature analysis

Eye tracking was used to measure visual attention of nine forensic document examiners (FDEs) and 12 control subjects on a blind signature comparison trial. Subjects evaluated 32 questioned signatures (16 genuine, eight disguised, and eight forged) which were compared, on screen, with four known signatures of the specimen provider while their eye movements, response times, and opinions were recorded. FDEs' opinions were significantly more accurate than controls, providing further evidence of FDE expertise. Both control and FDE subjects looked at signature features in a very similar way and the difference in the accuracy of their opinions can be accounted for by different cognitive processing of the visual information that they extract from the images. In a separate experiment the FDEs re-examined a reordered set of the same 32 questioned signatures. In this phase each signature was presented for only 100 msec to test if eye movements are relevant in forming opinions; performance significantly dropped, but not to chance levels indicating that the examination process comprises a combination of both global and local feature extraction strategies.     

几种眼外伤鉴定时机的研究

目的分析几种眼外伤的伤后视力稳定时间,研究最早且合适的鉴定时机。方法将145件案例160个伤眼按损伤类型分成5组,研究几种眼外伤后视力水平、眼外伤类型与视力稳定时间的关系。结果不同的眼外伤,其视力稳定时间有较大差异,且视力水平的高低与视力稳定时间也有明显的相关性。结论眼外伤最早的合适鉴定时机既与眼外伤的类型有关,也与伤后视力水平有关;应灵活掌握鉴定时机,以适应司法机关的需要。