Initial Study for the Determination of the Sequence of Intersecting Lines between Gel Pens and Seals by Optical Coherence Tomography*

Determining the sequence of intersecting lines is a significant issue in the forensic document examination that can reveal the fraud or distinguish between different allegations. Optical coherence tomography (OCT) is a high-resolution cross-sectional imaging technique that has been introduced into forensic science field recently. The potential of OCT as a novel method to determine the sequence of intersecting lines was examined for the first time. In this study, a spectral-domain OCT system with a center wavelength of 900 nm was employed to perform nondestructive examination on determining the sequence of 18 heterogeneous intersecting line samples produced using three types of gel pens and three brands of stamp pad ink seals. Two-dimensional (2D) cross-sectional, and three-dimensional (3D) volumetric images of the intersecting lines were obtained by the OCT system. Several features were noted and analyzed to successfully determine the sequence of all the 18 samples. Blind tests were also conducted to demonstrate the effectiveness of OCT technique. The results illustrate that OCT technology can provide an effective and accurate method for sequencing intersecting lines of gel pen ink and seal ink, which may complement the conventional methods used in the examination of questioned documents.     

Parental reference photos do not always improve the accuracy of forensic age progressions

During long-term missing children cases, forensic artists construct age-progressions to estimate the child’s current appearance. It is commonly believed that incorporating information about the child’s biological relatives is critical in accurately estimating the child’s current appearance. However, some evidence suggests that predicting appearance based on inheritance of features may be error prone. The present studies examine whether age-progressions constructed with the aid of a biological reference photos led to better recognition than those constructed without a biological reference. We also investigated whether there would be any variation depending on the age-range of the age-progressions. Eight professional forensic artists created age-progressions based upon photographs provided by each of our eight targets. Half of their age progressions with the aid of parental reference photos and half without parental reference photos. Furthermore, half were age-progressed across a longer age-range (5–20 years) and half covered a shorter age-range (12–20 years). In Experiment 1 similarity scores were higher over shorter age-ranges. Further, across longer age-ranges age-progressions created with the aid of a parental reference were lower than those without a reference. In Experiment 2 recognition performance was higher across shorter age-ranges. Additionally, across longer age-ranges age-progressions created with the aid of a parental reference were recognized worse than those without a reference. These results suggest that in long-term missing person cases, forensic artists may benefit from not relying on biological references. Finally, consistent with previous research (e.g. Lampinen et al., 2012) age-progressions provided no benefit over using outdated photographs.     

DESI-HRMS-HDI在添改字迹鉴定中的应用研究

目的 通过电喷雾解吸电离(DESI)—高分辨飞行时间质谱(HRMS-HDI)成像技术建立了 一种新型添改字迹鉴别技术.方法 对10支黑色签字笔书写的"11"被添改成"47"的90个样本用分子成像技术测试.结果 该技术可将84个被添改的原始字迹"11"以二维成像方式显现.结论 DESI-HRMS-HDI技术无需检材预处理...     

The Effect of Time and Temperature on the Persistence and Quality of Latent Fingerprints Recovered from 60-Watt Incandescent Light Bulbs

To understand how time and temperature could affect latent fingerprints, wooden pallets were used to construct five units that each housed ten 60-watt incandescent light bulbs. Fingerprints were deposited on the top, middle, and base of the globes. The bulbs were powered on (except the control bulb in each unit) for 18, 48, 72, 120, 168, 336, 504, and 672 h. Fingerprints recovered from the bulbs by tape lift after black powder processing were given a quality score. A thermal imaging camera determined temperatures on three areas of the bulbs. Fingerprints on the top of the globe (156.3°C) had the lowest quality score, and fingerprints on the middle of the globe (112.6°C) had the highest quality score. The mean quality scores of the three temperature classes were within one standard deviation of one another, meaning there is no way to estimate fingerprint age based on its quality after heat exposure.     

针刺持续时间及刺激方案对针刺脑功能成像的影响

目的 利用BOLD-fMRI技术,在保持其他影响因素不变的情况下研究针刺持续时间及针刺刺激方案对脑功能成像激活区定位的影响。方法 选取健康志愿者40例,平均分为2组,为持续时间组及刺激方案组,第1组采用相同的针刺刺激方案（改良组块设计）进行3轮（R1、R2、R3）功能像数据采集,第2组采用3种不同的针刺刺激方案（包括典型组块、改良组块设计及事件相关设计）进行3轮功能像采集,两组数据均采用相同的MR扫描参数,用AFNI软件进行数据处理,用Monte Carlo阈值校正方法确定脑功能激活区,得出每组的组内分析结果及组内不同轮次比较的结果。 结果 持续时间组及刺激方案组的组内fMRI信号存在明显差异。组内不同轮次fMRI信号比较也均存在显著差异的脑区,两组的R2与R1相比均存在fMRI信号减低区域,但刺激方案组的R3与R1相比存在广泛的fMRI信号减低区域,持续时间组的R3与R1相比存在fMRI信号增高区域。 结论 针刺持续时间及刺激方案均会对脑功能成像的激活区定位产生影响。     

针刺舌根部穴对人生理状态下吞咽功能影响的功能性核磁共振成像研究

目的通过对比健康成人舌根部穴针刺前后执行吞咽任务时脑功能区的激活差异,探讨针刺舌根部穴对吞咽功能影响的中枢机制。方法青年健康志愿者10名,分别于针刺舌根部穴前后运用功能磁共振技术进行吞咽任务(含静息状态、吞咽准备和吞咽任务)扫描,分析针刺前后数据集,获得针刺舌根部穴后执行吞咽任务的差异脑功能激活区。结果针刺前,脑激活区主要分布于左侧的颞上回和右侧的岛叶;针刺后,脑激活区主要分布于左侧小脑后叶、小脑叶、梭状回以及右侧舌状回,负激活区主要分布于左侧中央前回、中央后回以及右侧中央后回;针刺前后对比,差异脑激活区分布于左侧的梭状回、颞中回及额内侧回,负激活区位于左侧顶下小叶。结论针刺舌根部穴影响吞咽功能的原因可能是通过增强吞咽相关脑区参与任务执行的积极性,提高吞咽任务执行效率,以达到调节吞咽运动肌群的目的。     

Juvenile Facial Growth and Mimicry: A Preliminary 3D Study

Studies focused on facial development during childhood have been conducted by means of 3D technology to provide modifications of anthropometric parameters. Facial mobility was also considered. This study proposed a 3D approach to facial growth changes. Facial surface data of 6 subjects were acquired in T1 (age 7–14 years) and after 7 years (T2), in rest position, and during voluntary movements, by a 3D laser scanner. Linear and angular measurements on rest position scans at T1 and T2 were compared. Each mimic scan was superimposed with the corresponding rest scan. Displacement of significant anthropometric points was measured for each facial gesture and at T1 and T2 statistically compared. Vertical measurements were those most influenced by aging. Some measurements of central facial area were consistent over time. The pattern of soft tissues displacement for each expression was consistent in T1 and T2. These results may be helpful for missing children identification.     

Whole body postmortem magnetic resonance angiography

Computed tomography (CT) and magnetic resonance (MR) imaging have become important elements of forensic radiology. Whereas the feasibility and potential of CT angiography have long been explored, postmortem MR angiography (PMMRA) has so far been neglected. We tested the feasibility of PMMRA on four adult human cadavers. Technical quality of PMMRA was assessed relative to postmortem CT angiography (PMCTA), separately for each body region. Intra-aortic contrast volumes were calculated on PMCTA and PMMRA with segmentation software. The results showed that technical quality of PMMRA images was equal to PMCTA in 4/4 cases for the head, the heart, and the chest, and in 3/4 cases for the abdomen, and the pelvis. There was a mean decrease in intra-aortic contrast volume from PMCTA to PMMRA of 46%. PMMRA is technically feasible and allows combining the soft tissue detail provided by MR and the information afforded by angiography.     

Preliminary Observations on the Ability of Hyperspectral Imaging to Provide Detection and Visualization of Bloodstain Patterns on Black Fabrics

Abstract: The analysis of bloodstain patterns can assist investigators in understanding the circumstances surrounding a violent crime. Bloodstains are routinely subjected to pattern analysis, which is inherently dependent upon the ability of the examiner to locate and visualize bloodstain patterns on items of evidence. Often, the ability to properly visualize bloodstain patterns is challenging, especially when the stain patterns occur on dark and/or patterned substrates. In this study, preliminary research was performed to better understand how near‐infrared reflectance hyperspectral imaging (HSI) could be used to observe bloodstain patterns on commonly encountered black fabrics. The ability of HSI to visualize latent bloodstains on several commonly encountered substrates is demonstrated. The images acquired through HSI are of sufficient quality to allow for differentiation between stains produced from an impact mechanism or a transfer mechanism. This study also serves as a proof of concept in the differentiation of multiple staining materials. Because of its ability to generate spectral data, the data provide a preliminary separation of stains where more than one type of stain existed.     

Optimizing Ballistic Imaging Operations

Ballistic imaging systems can help solve crimes by comparing images of cartridge cases, which are recovered from a crime scene or test‐fired from a gun, to a database of images obtained from past crime scenes. Many U.S. municipalities lack the resources to process all of their cartridge cases. Using data from Stockton, CA, we analyze two problems: how to allocate limited capacity to maximize the number of cartridge cases that generate at least one hit, and how to prioritize the cartridge cases that are processed to maximize the usefulness (i.e., obtained before the corresponding criminal case is closed) of hits. The number of hits can be significantly increased by prioritizing crime scene evidence over test‐fires, and by ranking calibers by their hit probability and processing only the higher ranking calibers. We also estimate that last‐come first‐served increases the proportion of hits that are useful by only 0.05 relative to first‐come first‐served.