Project description:Linking biological samples found at a crime scene with the actual crime event represents the most important aspect of forensic investigation, together with the identification of the sample donor. While DNA profiling is well established for donor identification, no reliable methods exist for timing forensic samples. Here, we provide for the first time a biochemical approach for determining deposition time of human traces. Using commercial enzyme-linked immunosorbent assays we showed that the characteristic 24-h profiles of two circadian hormones, melatonin (concentration peak at late night) and cortisol (peak in the morning) can be reproduced from small samples of whole blood and saliva. We further demonstrated by analyzing small stains dried and stored up to 4 weeks the in vitro stability of melatonin, whereas for cortisol a statistically significant decay with storage time was observed, although the hormone was still reliably detectable in 4-week-old samples. Finally, we showed that the total protein concentration, also assessed using a commercial assay, can be used for normalization of hormone signals in blood, but less so in saliva. Our data thus demonstrate that estimating normalized concentrations of melatonin and cortisol represents a prospective approach for determining deposition time of biological trace samples, at least from blood, with promising expectations for forensic applications. In the broader context, our study opens up a new field of circadian biomarkers for deposition timing of forensic traces; future studies using other circadian biomarkers may reveal if the time range offered by the two hormones studied here can be specified more exactly.
Project description:Poisoning occurs frequently in TV crime series but, to the best of our knowledge, has not yet been analyzed scientifically. This study examines the plausibility of poisoning cases in Germany's most popular crime series, Tatort (crime scene), from 1974 to 2022. In the TV series, the increasing rate of poisoning in Germany as well as the increasing variety of substances leading to poisoning over the years are depicted. Largely in line with reality, similar substance categories and routes of administration are presented. However, poisoning outcomes in Tatort differ from reality: over 50% of the victims die in Tatort, whereas in reality, more than 80% survive. In > 95% of the episodes, the mechanism of action of a poison is not explained, omitting an important opportunity for raising public awareness. The TV series also deviates from reality in terms of the etiology of poisonings: External poison delivery is largely overrepresented, while the high rate of accidental poisonings in real life is underrepresented. Almost no accidental poisonings occur in Tatort, although this is the most frequent type of poisoning in real life. In Tatort, men are overrepresented as offenders and victims of poisoning compared to reality. Thus, the crime series does not convey the message that anyone can be a potential victim of poisoning and that particularly vulnerable groups need proper education and the best possible protection. This paper discusses the conflict between detailed, plausible episodes with cases of poisoning and the potential for imitation that they may cause.
Project description:This project's main objective is to create an open-source database containing a sizeable number of high-quality images of shoe impressions. The Center for Statistics and Applications in Forensic Evidence (CSAFE) team collected images that represented those found at crime scenes and constructed a database that is publicly available to forensic science and research communities. The database includes images obtained from mixed impression types: full blood impression, partial blood impression, and dust impression. The impressions are made on different flooring (vinyl and tile), and captured via various lift techniques: gel lifts and handiprints (exemplar prints with high definition using graphite powder and clear sticky vinyl, backed by a white sheet), and saved in multiple digital file types (TIF, XMP, CR3, and JPG). Our data were collected to ensure reproducibility, using simple but well-described protocols and easily accessible materials. The complete dataset includes 936 unique shoeprint images saved in 3,275 digital files. Data were collected by trained volunteers making shoe impressions on flooring with the two mediums: spatter blood and graphite powder. To make an impression, volunteers wearing a shoe stepped into the material and then walked on the flooring. A separate "lighter" step was taken to create a partial print for the blood prints. The blood prints were brought to the photography station, where researchers labeled and photographed them. Graphite prints were covered with a gel lifter before being moved to the photography room. There, the researchers removed the lift, labeled, and then photographed them. Our data will be of significant use to researchers, examiners, and anyone who could benefit from using a large dataset like this. Footwear datasets are often difficult to find, especially ones that resemble crime scenes, so our data can help fill that gap.
Project description:One of the current trends in the study of criminal profiling consists of developing theoretical and methodological typologies to offer information of operational use in police investigations. The objective of this work was to verify the validity of the instrumental/expressive model, so as to establish homicide typologies based on modus operandi relationships, characteristics of the victims, and characteristics of perpetrators. The sample consisted of 448 homicide cases registered in the database of the Homicide Revision Project of the Office of Coordination and Studies of the Spanish Secretary of State and Security. Through multidimensional scaling and cluster analysis, three expressive homicide subtypes were identified (expressive-impulsive, expressive-distancing, and expressive-family), as well as two instrumental homicide subtypes (instrumental-opportunist and instrumental-gratification). The expressive homicide typologies accounted for almost 95% of all of the studied cases, and most of the homicides occurring in Spain were found to take place between individuals who know one another (friends, family members, intimate couples/ex-couples). The findings from this study suggest that the instrumental/expressive model may be a useful framework for understanding the psychological processes underlying homicides, based on the study of relationships between the crime and aggressor characteristics, which may be very helpful in the prioritization of suspects.
Project description:Inflammatory bowel diseases (IBD) are without cure and troublesome to manage because of the considerable diversity between patients and the lack of reliable biomarkers. Several studies have demonstrated that diet, gut microbiota, genetics and other patient factors are essential for disease occurrence and progression. Understanding the link between these factors is crucial for identifying molecular signatures that identify biomarkers to advance the management of IBD. Recent technological breakthroughs and data integration have fuelled the intensity of this research. This research demonstrates that the effect of diet depends on patient factors and gut microbial activity. It also identifies a range of potential biomarkers for IBD management, including mucosa-derived cytokines, gasdermins and neutrophil extracellular traps, all of which need further evaluation before clinical translation. This review provides an update on cutting-edge research in IBD that aims to improve disease management and patient quality of life.
Project description:BackgroundThe success of forensic DNA analysis is limited by the size, quality and purity of biological evidence found at crime scenes. Sample impurities can inhibit PCR, resulting in partial or negative DNA profiles. Various DNA purification methods are applied to remove impurities, for example, employing centrifugal filter devices. However, irrespective of method, DNA purification leads to DNA loss. Here we evaluate the filter devices Amicon Ultra 30 K and Microsep 30 K with respect to recovery rate and general performance for various types of PCR-inhibitory crime scene samples.MethodsRecovery rates for DNA purification using Amicon Ultra 30 K and Microsep 30 K were gathered using quantitative PCR. Mock crime scene DNA extracts were analyzed using quantitative PCR and short tandem repeat (STR) profiling to test the general performance and inhibitor-removal properties of the two filter devices. Additionally, the outcome of long-term routine casework DNA analysis applying each of the devices was evaluated.ResultsApplying Microsep 30 K, 14 to 32% of the input DNA was recovered, whereas Amicon Ultra 30 K retained 62 to 70% of the DNA. The improved purity following filter purification counteracted some of this DNA loss, leading to slightly increased electropherogram peak heights for blood on denim (Amicon Ultra 30 K and Microsep 30 K) and saliva on envelope (Amicon Ultra 30 K). Comparing Amicon Ultra 30 K and Microsep 30 K for purification of DNA extracts from mock crime scene samples, the former generated significantly higher peak heights for rape case samples (P-values <0.01) and for hairs (P-values <0.036). In long-term routine use of the two filter devices, DNA extracts purified with Amicon Ultra 30 K were considerably less PCR-inhibitory in Quantifiler Human qPCR analysis compared to Microsep 30 K.ConclusionsAmicon Ultra 30 K performed better than Microsep 30 K due to higher DNA recovery and more efficient removal of PCR-inhibitory substances. The different performances of the filter devices are likely caused by the quality of the filters and plastic wares, for example, their DNA binding properties. DNA purification using centrifugal filter devices can be necessary for successful DNA profiling of impure crime scene samples and for consistency between different PCR-based analysis systems, such as quantification and STR analysis. In order to maximize the possibility to obtain complete STR DNA profiles and to create an efficient workflow, the level of DNA purification applied should be correlated to the inhibitor-tolerance of the STR analysis system used.
Project description:This introductory laboratory exercise gives first-year life science majors or nonmajors an opportunity to gain knowledge and experience in basic bioinformatics and molecular biology laboratory techniques and analysis in the context of a mock crime scene investigation. In this laboratory, students determine if a human (Lady) or dog (Kona) committed the fictional crime of scaring a cat. Students begin by performing in silico PCR using provided dog- and human-specific PCR primers to determine the sequences to be amplified and predict PCR amplicon sizes. They then BLAST (Basic Local Alignment Search Tool) the in silico PCR results to confirm that the PCR primers are designed to amplify genomic fragments of the cardiac actin gene in both dogs and humans. Finally, they use DNA quantification techniques, PCR, and agarose gel electrophoresis to identify the culprit and they confirm results by analyzing Sanger sequencing. Student learning gains were demonstrated by successful execution of the lab and by analysis and interpretation of data in the completion of laboratory reports. The student learning gains were also demonstrated by increased performance on a post-laboratory assessment compared to the pre-assessment. A post-activity assessment also revealed that students perceived gains in the skills and conceptual knowledge associated with the student learning outcomes. Finally, assessment of this introductory molecular biology and bio-informatics activity reveals that it allows first-year students to develop higher-order data analysis and interpretation skills.
Project description:Were he alive today, would Louis Pasteur still champion culture methods he pioneered over 150 years ago for identifying bacterial pathogens? Or, might he suggest that new molecular techniques may prove a better way forward for quickly detecting the true microbial diversity of wounds? As modern clinicians faced with treating complex patients with diabetic foot infections (DFI), should we still request venerated and familiar culture and sensitivity methods, or is it time to ask for newer molecular tests, such as 16S rRNA gene sequencing? Or, are molecular techniques as yet too experimental, non-specific and expensive for current clinical use? While molecular techniques help us to identify more microorganisms from a DFI, can they tell us 'who done it?', that is, which are the causative pathogens and which are merely colonizers? Furthermore, can molecular techniques provide clinically relevant, rapid information on the virulence of wound isolates and their antibiotic sensitivities? We herein review current knowledge on the microbiology of DFI, from standard culture methods to the current era of rapid and comprehensive 'crime scene investigation' (CSI) techniques.
Project description:The case relates to a bookstore owner claiming that two DM-41 hand grenades were exploded simultaneously in his store. There were three males together at the store when the explosion occurred. One was the owner who claimed that he escaped after the explosion without any harm; the other was at the corner lying down to prevent his body from the explosion effect. He survived with very minor, almost no effects.According to the hospital report, it was stated that "cuts on the right femur with sizes of 0.5x2 and 0.5x1 cm and one cut of 0.5x2,0 cm on the left food which are curable with simple medical intervention; generalized skin erosions on body with the sizes between 0,5 to 1,0 cm"; the third male was standing and killed. He was next to the lying down male. At the autopsy report it was stated that the he was killed due to the shrapnel/fragmentation effect, breaks on humerus, radius, femur and cranium; cerebral and internal hemorrhage. The males witnessed at the court that they had survived with no vital damage on their bodies, they had seen the perpetrators and heard them talking. With the fact that the deceased male was intensively affected with the fragmentation/shrapnel due to the autopsy report, it was the court's wonder if it is possible for the survived men to have no or very minor nonfatal fragmentation effect on their bodies even being in the same room with the deceased.It was mainly aimed to test the fragmentation effect of 2 DM-41 defence hand grenades when detonated in a closed environment (an empty room with the approximately same size of the related case). The test room was empty with no secondary fragmentation sources as window glasses etc. 3 male mannequins were used as test materials. With the post blast reconstruction of the crime scene, it was aimed to determine if the test results and the autopsy report are very coherent and the persons having the direct blast effect would be expected having maximum exposure to the fragmentation.
Project description:Lensless imaging has emerged as a potential solution towards realizing ultra-miniature cameras by eschewing the bulky lens in a traditional camera. Without a focusing lens, the lensless cameras rely on computational algorithms to recover the scenes from multiplexed measurements. However, the current iterative-optimization-based reconstruction algorithms produce noisier and perceptually poorer images. In this work, we propose a non-iterative deep learning-based reconstruction approach that results in orders of magnitude improvement in image quality for lensless reconstructions. Our approach, called FlatNet, lays down a framework for reconstructing high-quality photorealistic images from mask-based lensless cameras, where the camera's forward model formulation is known. FlatNet consists of two stages: (1) an inversion stage that maps the measurement into a space of intermediate reconstruction by learning parameters within the forward model formulation, and (2) a perceptual enhancement stage that improves the perceptual quality of this intermediate reconstruction. These stages are trained together in an end-to-end manner. We show high-quality reconstructions by performing extensive experiments on real and challenging scenes using two different types of lensless prototypes: one which uses a separable forward model and another, which uses a more general non-separable cropped-convolution model. Our end-to-end approach is fast, produces photorealistic reconstructions, and is easy to adopt for other mask-based lensless cameras.