Use of laser-scanning confocal microscopy in the detection of diagenesis in bone

This research demonstrates the value of laser scanning confocal microscopy (LSCM) as a research tool in osteological studies, and diagenetic studies in particular. LSCM combines properties of light and scanning electron microscopy using laser light to excite fluorophores throughout the z-axis, developing a 3-D image. Using differential staining and selecting for specific wavelengths of light, one can image targeted materials. This research is divided into two parts: visualizing bone structures such as proteins and their decompositional products and visualizing diagenesis. Part one of this study utilized pig bones as a means of testing the overall ability of LSCM to fluoresce bone. Twenty-three samples were imaged, including 13 samples from a decompositional study conducted 5 years previous, and 10 “fresh” samples collected from a commercial butcher. This part of the study determined that protein and organic components of the bone could be fluoresced and diagenetic alteration could be imaged. The second part of the study used human samples as a means of imaging and mapping diagenetic alterations. The second part of the study used 13 samples, including 4 clinical, 7 ancient, and 2 modern controls. The pig study used Basic Fuchsin and SlowFade Gold stains, while the human study used toluidine blue. Images were also taken with unstained elements. The results of the non-human study found that a fresh bone fluoresced differently than that of a 5-year subset, while the results of the human study confirmed these findings and determined that the bone diagenesis can be mapped using LSCM.     

以共同育儿为业:跨越儿童抚育的家庭边界——以一个城市社区的“抱团养娃”实践为例

本文聚焦于城市化背景下的"抱团养娃"实践,深入探讨在抚育职责被"家庭化"的当下,抚育实践如何在一定程度上重新跨越"家庭"的边界。以社区共育为基点,妈妈们的努力既从私人层面上为在陌生城市中资源不足的小家庭找到更多社会支持,又在公共层面上带动孩子们以温度和情感重塑社区认同、黏合社会转型带来的制度缝隙,体现出独特的现实意义与支持力量。"以共同育儿为业"背后,是女性试图在既有的结构约束下找到被私人化的抚育照料重担与公共生活之间的连接点,在本研究中体现为共育支持网络的形成、共育友好空间的营造、亲子活动内容的生产和共育文化的建构四个方面。这为思考如何将"社会"重新带回抚育实践中提供了想象,也拓宽了对女性主体性的理解。     

Fatal penetrating abdominal injury by a metallic projectile

Penetrating abdominal injury is often a life-threatening condition, which is mainly associated with inflicted injuries. Fatal self-inflicted sharp force abdominal injuries too have been reported in the literature. Inadvertent penetrating abdominal injuries are a rarity and are caused by sharp objects of low-velocity and often nonmissile-type. A 27-year-old male factory worker was brought dead to the emergency department with an alleged history of sustaining abdominal injury by a sharp metal projectile while working on a metal cutting grinder. Autopsy observations were consistent with the history of inadvertent penetrating injury. Our case reports a fatal missile-type inadvertent sharp force trauma over the abdomen with intestinal perforation, a relatively uncommon scenario in occupational/workplace settings. The present case report describes the significance of the death scene visit and corroborating the medical findings with investigating agencies. This case further emphasizes on the need for adopting proper safety measures at the workplace.     

A novel method for cyanide quantification in human whole blood using ion chromatography with amperometric detection and its application to cyanide intoxication cases

Cyanide is a highly toxic agent that has been frequently used for suicide in South Korea. It is also used in various industrial fields, such as metal plating, in which many accidental cyanide intoxications have occurred. To overcome the disadvantages of conventional cyanide analysis methods, a simple and fast method for the analysis of cyanide in whole blood using ion chromatography (IC) with amperometric detection was developed in this study. Whole blood samples were deproteinized, diluted, and analyzed using an IC–amperometric detection system. The limits of detection and quantitation were 0.1 and 0.2 mg/L, respectively. The method showed good linearity in the range of 0.2 to 50 mg/L with R² > 0.99. The intra- and inter-assay precision and accuracy values were <10%. The established method was successfully applied to analyze whole blood samples from three cyanide intoxication cases.     

A mixed DNA profile controversy revisited

Semaan et al. (J Forensic Res, 2020, 11, 453) discuss a mock case “where eight different individuals [P₁ through P₈] could not be excluded in a mixed DNA analysis. Even though … expert DNA mixture analysis software was used.” Two of these are the true donors. The LRs reported are incorrect due to the incorrect entry of propositions into LRmix Studio. This forced the software to account for most of the alleles as drop-in, resulting in LRs 60–70 orders of magnitude larger than expected. P₁, P₂, P₄, P₅, and P₈ can be manually excluded using peak heights. This has relevance when using LRmix which does not use peak heights. We extend the work using the same two reference genotypes who were the true contributors as Semaan et al. (J Forensic Res, 2020, 11, 453). We simulate three two-donor mixtures with peak heights using these two genotypes and analyze using STRmix?. For the simulated 1:1 mixture, one of the non-donors’ LRs supported him being a contributor when no conditioning was used. When considered in combination with any other potential donors (i.e., with conditioning), this non-donor was correctly eliminated. For the 3:1 mixture, all results correctly supported that the non-donors were not contributors. The low-template 4:1 mixture LRs with no conditioning showed support for all eight profiles as donors. However, the results from pair-wise conditioning showed that only the two ground truth donors had LRs supporting that they were contributors to the mixture. We recommend the use of peak heights and conditioning profiles, as this allows better sensitivity and specificity even when the persons share many alleles.     

Metric forensic anthropology decisions: Reliability and biasability of sectioning-point-based sex estimates

Subjective decisions make human cognitive processes more susceptible to bias and error. Specifically, research indicates that additional context biases forensic anthropologists’ morphological analyses. To address whether metric analyses are also subject to bias, we conducted a pilot study in which 52 experienced osteologists measured a difficult-to-classify human femur, with or without additional contextual information. Using a metric sectioning-point sex-estimation method, participants provided a sex estimate for individual skeletal element(s) and, when given multiple elements, the combined skeletal assemblage. Control group participants (n = 24) measured only the femur. In addition to the femur, bias group participants (n = 28) either measured a female humerus and viewed a female-biasing photograph (n = 14) or measured a male humerus and viewed a male-biasing photograph (n = 14). We explored whether the experts in the different groups would differ in: (1) femoral measurements; (2) femoral sex-estimation conclusions; and (3) final sex-estimation conclusions for the skeletal assemblage. Although the femoral measurements and femoral sex estimates were comparable across groups, the overall sex estimates in the female-biased group were impacted by contextual information—differing from both the control and male-biased groups (p < 0.001). Our results demonstrate that cognitive bias can occur even in metric sex-estimation conclusions. Specifically, this occurred when the metric data and single-element sex estimates were synthesized into an overall estimate. Thus, our results suggest that metric methods are most vulnerable to bias when data are synthesized into an overall conclusion, highlighting the need for bias countermeasures and comprehensive statistical frameworks for synthesizing metric data to mitigate the effects of cognitive bias.     

Observer determination of the make,model, and year of questioned vehicles

Often, criminal acts involving a vehicle are caught on digital video surveillance systems. While potentially useful for an investigation, the recording conditions are typically less than optimal for the extraction of key information for the identification of the perpetrator, such as a license plate. Providing the make, model and year of a questioned vehicle is a common request for examiners, to narrow the field of potential suspect vehicles. This study seeks to compare the performance of a nonpeer-reviewed make, model, and year determination between two separate groups, specifically, trained forensic image examiners and nontrained individuals. Results show that even with varied image capture conditions and quality, the trained forensic image examiners more correctly and completely identified the test group of questioned vehicles make, model, and year.     

Publication rates of abstracts presented at the annual scientific meetings held by the American Academy of Forensic Sciences in 2011 and 2016

Prior research evaluating the papers presented in forensic sciences in international meetings is scant. This study determines the possible predictions concerning publications by comparing the publication rates, publication years, and presentation types, time until publication, participating countries, and criteria of the published journals in the American Academy of Forensic Sciences (AAFS). The publication rates of abstracts presented at scientific meetings of AAFS, a prestigious forensic science organization, along with the aforementioned components and the extent of their contribution in 2011 and 2016 were investigated. The abstracts presented at the AAFS meetings in 2011 and 2016 were reviewed retrospectively within the scope of this study. The Web of Science, PubMed, Scopus, Science Direct, and Google Scholar databases were searched using a specified process that included the title, first and last author surnames, and keywords. Results revealed that approximately 21% and 24% of the papers presented at the 2011 and 2016 AAFS meetings, respectively, were published. Considering the publication rates of abstracts according to sections, the publication rates for the 2011 AAFS meeting ranged from 4% (questioned documents) to 31% (anthropology) and from 5% (questioned documents) to 32% (pathology/biology), on average, for the 2016 AAFS meeting. It was determined that the papers were largely published in the Journal of Forensic Sciences for both annual scientific meetings. Future studies should concentrate on the obstacles to the publication of papers presented at such prestigious organizations and strategies to facilitate the publication process such that they do not lose their value over time.     

Determination of average vehicle speed utilizing reverse projection

Reverse projection photogrammetry has long been used to estimate the height of an individual in forensic video examinations. A natural extrapolation would be to apply the same technique on a video to estimate the speed of an object by determining the distance traveled between two points over a set amount of time. To test this theory, five digital video recorders (DVRs) were connected to a single fixed camera to record a vehicle traveling down a track. The vehicle's speed was measured through Doppler radar by a trained operator and the speedometer of the vehicle was also recorded with a video camera. The recorded video was examined and the frames that best depict the beginning and end of the vehicles course were selected. Two reverse projection photogrammetric examinations were performed on the selected frames to establish the position of the vehicle. The distance between the two points was measured, and the time elapsed between the two points was examined. The outcome provided an accurate speed result with a standard degree of uncertainty. This study proves the feasibility of using video data and reverse projection photogrammetry to determine the speed of a vehicle with a limited set of variables. Further research is needed to determine how additional variables would impact the standard degree of uncertainty.     

Lethal small bowel obstruction due to pica

Up to 25% of institutionalized patients with cognitive deficiencies display pica-like behavior, with an estimated annual incidence of small bowel obstruction of 2%. We present a case based on the forensic autopsy of a 41-year-old woman who died as a result of a missed diagnosis of small bowel obstruction after ingesting a foreign body. The case underlines the importance of precaution when treating patients with cognitive deficiency and/or language deficits and gastrointestinal symptoms. In such cases, it is important to employ a liberal threshold for radiological investigations and, if possible, obtain a medical history from a person close to the patient.