1,380 research outputs found

    Using Synchrotron Infrared Spectroscopy and X-ray Fluorescence Microscopy to Explore Fingermark Chemistry

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    The recovery of fingermark evidence from a crime scene can be vital to forensic investigations. Despite the wide variety of current detection methods, many fingermarks are never recovered. This thesis describes the use of synchrotron-sourced X-ray fluorescence microscopy and infrared spectroscopy to investigate the spatial distribution and relative amounts of organic and inorganic materials in latent fingermarks. The findings will help improve fingermark detection methods and assist with the interpretation of fingermark evidence

    Fingerprint Enhancement by means of Electromagnetic Radiation: a Pilot Study to Drive Future Researches

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    Fingerprints are a worldwide well known tool for law enforcement agencies to reach the individualization of people convicted of a crime. Moreover, all major countries have huge fingerprint databases and efficient automated systems (AFIS) to perform electronic screening of fingerprints marks recovered by crime scene investigation. Fingerprints are permanent and even if, from a scientific point of view, they could not be considered unique, friction ridge is highly selective and allows a discrimination between different individuals with a very high proficiency. Up to now, the most common techniques for enhancing latent fingerprints from articles collected in the crime scene are based on chemical-physical processes, or optical detection techniques, based on absorption, photoluminescence, diffused reflection or ultraviolet imaging, with appropriate band-pass and/or narrow-band filtering. Chemical-physical processes have shown really good performances, but they are destructive with respect to the latent finger mark deposit and in most cases these methods partially affect subsequent DNA analysis. On the other side, optical detection processes have the advantage of being non-destructive of the fingerprint. As a result, these techniques allow later performing of DNA analysis and/or the further application of conventional fingerprint development procedures. The majority of the optical techniques, with the possible exception of the ultraviolet inspection, allow further biological analysis. And as the aforementioned methods have the advantage of being non alterative with the respect of the fingerprint deposit, subsequent application of chemical and/or physical methods is not precluded. Moreover, some recent studies are investigating the X-ray fluorescence of fingerprints, and some others are attempting to discriminate the IR spectrum of the finger mark deposit from the IR spectrum of the surface. It is easy to understand how crucial is to develop a robust technique of optical analysis, able to reach a high-resolution imaging of finger marks, requiring no chemical conventional or non-conventional pre-process and producing no modification either on the finger perspiration deposit or on the background surface. The proper image of the fingerprint, obtained from the item surface, could allow us to perform a complete fingerprint analysis, which potentially leads us to the individualization of the perpetrator. Moreover, fingerprint imaging could exactly point out the particular region of the whole surface where we can surely find the DNA of the donor, with a higher probability of successful analysis

    Ion Beam, Synchrotron Radiation, and Related Techniques in Biomedicine: Elemental Profiling of Hair

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    Elements play an imperative role in the physiological and metabolic processes of the human body. When elemental levels deviate from physiologically accepted levels due to for example poor nutrition, the body’s intricate elemental and metabolic balance is disturbed. Over time, disease may develop as a result of elemental dyshomeostasis or alternatively, disease may trigger elemental dyshomeostasis as an adaptive metabolic response to an unhealthy environment. There is now a growing interest in screening human tissue to identify and quantify elemental changes as biomarkers of disease or alternatively, as outcomes of disease. The unique properties of human hair brand it the ideal substrate for the quantitative identification of elements in the body. Hair bioaccumulates elements, provides a historical overview of elemental status depending on length, and is easy and economical to sample and store. The fundamental outcome and application of hair elemental screening, however, are strongly influenced by a range of factors, including choice of analytical method. This chapter will provide a background summary of ion beam and synchrotron radiation techniques and its diverse applications for unraveling the elemental signature of hair in various fields

    Human Hair as a Testing Substrate in the Era of Precision Medicine: Potential Role of ‘Omics-Based Approaches

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    Minimally and noninvasive investigation of pathology and treatment monitoring is highly attractive in medicine. The use of human hair samples as a non-invasive testing substrate is potentially poised to improve diagnostic and forensic medicine. Hair has the unique ability to capture long-term information about health and disease in an individual as compared to urine and blood. Testing long hair offers a potential means of long-term monitoring of drug compliance, drug abuse, chronic alcohol abuse, and diagnostic biomarker discovery. Even though human hair is mostly composed of keratin and keratin-associated proteins, very little literature has been published on human hair proteomics. Emerging high throughput omics based techniques such as proteomics are increasingly improving our depth of knowledge about the diagnosis, prognosis and prediction of diseases globally. Although many aspects of the use of these novel molecular aids to improve disease diagnosis and patient management remains elusive; it is evident that these techniques have improved precision medicine tremendously. This chapter aims to discuss current plausible application of human hair omics-based approaches to the field of pathology, diagnostics and precision/individualized medicine

    RADIOLOGICAL APPLICATIONS IN FORENSIC ANTHROPOLOGY. FRACTURE HEALING AND DATING

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    The accurate dating of bone fractures constitutes a critical component of trauma analysis in forensic anthropology and the research in this field represents to date a challenging opportunity to apply scientific knowledge and methods to real problems of society, including also global humanitarian and human rights issues. However, the literature review performed in order to describe the state of the art in fracture healing and dating showed that forensic studies are scarce and that the assessment of fractures lacks consensus about both the definition of fracture healing and the duration of the fracture healing process. Thus, the aim of the present PhD project, including two research lines, was to acquire a better knowledge of the process of bone remodeling both in the living and the dead with regard to the timing of injury as well as to evaluate the applicability of high-resolution radiological techniques for objective dating of the healing phase of the fracture. The 1 st retrospective study, dedicated to the living, was based on digital radiographs from the largest adult living population ever analyzed and was aimed not only at examining time frames for healing of bone fractures but also at investigating the effect of variables, including age, sex, bone type and number of fracures on the timing of healing stages of traumatic skeletal lesions. For these purposes a multivariable model was built, which showed a significant association between the healing stages and the variables analyzed, so that a dynamic nomogram was preliminary proposed to predict a time interval since fracture from digital radiographs. The 2 nd experimental study, dedicated to the dead, was based on dry human bones presenting calluses of different known age in order to preliminary assess the potential of an advanced and non-destructive imaging technology, like microcomputed tomography (micro-CT), in order to obtain a future objective dating of the healing phase of the fracture on post-cranial human bone calluses of known age. The results not only demonstrated the potential utility of micro-CT to obtain a wealth of qualitative details about the microstructure of the callus but also to reach an objective fracture dating, laying promising foundations for further studies on this topic in light of the highlighted existence of a certain trend of some parameters of trabecular microstructure relative to the age of the callus, including the degree of anisotropy, the connectivity and the trabecular spacing

    Chemical characterisation and classification of forensic trace evidence

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    Automotive paint, in the form of paint chips and/or smears, is one of the most commonly encountered forms of forensic trace evidence located at automotive related incidents. There is an increasing demand for more scientifically rigorous approaches to the interpretation of such evidence. This dissertation presents studies examining the use of a suite of spectroscopic techniques in conjunction with multivariate statistics, in order to develop analytical and interpretational protocols for automotive paint evidence

    EVALUATING DIFFERENTIAL NUCLEAR DNA YIELD RATES AMONG HUMAN BONE TISSUE TYPES: A SYNCHROTRON MICRO-CT APPROACH

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    Molecular human identification has conventionally focused on DNA sampling from dense, weight-bearing cortical bone tissue from femora or tibiae. A comparison of skeletal elements from three contemporary individuals demonstrated that elements with high quantities of cancellous bone yielded nuclear DNA at the highest rates, suggesting that preferentially sampling cortical bone is suboptimal (Mundorff & Davoren, 2014). Despite these findings, the reason for the differential DNA yields between cortical and cancellous bone tissues remains unknown. The primary goal of this research is to ascertain whether differences in bone microstructure can be used to explain differential nuclear DNA yield among bone tissue types, with a focus on osteocytes and the 3D quantification of their associated lacunae. Osteocytes and other bone cells are recognized to house DNA in bone tissue, thus examining the density of their lacunae may explain why nuclear DNA yield rates differ among bone tissue types. Methods included: (1) quantifying cortical and cancellous bone volume from each bone-sampling site using Computed Tomography (CT), and (2) visualizing and quantifying osteocyte lacunae using synchrotron radiation micro-Computed Tomographic imaging (SR micro-CT). Regions of interest (ROIs) from cortical and cancellous bone tissues (n=129) were comparatively analyzed from the three skeletons sampled for Mundorff and Davoren’s (2014) study. Analyses tested the primary hypothesis that the abundance and density of bone’s cellular spaces vary between cortical and cancellous bone tissue types. Results demonstrated that osteocyte lacunar abundance and density vary between cortical and cancellous bone tissue types, with cortical bone ROIs containing a higher lacunar abundance and density. The osteocyte lacunar density values are independent of nuclear DNA yield, suggesting an alternative explanation for the higher nuclear DNA yields from predominantly cancellous bones. It is hypothesized that soft tissue remnants within the medullary cavities of primarily cancellous skeletal elements are driving the high nuclear DNA yields. These findings have significant implications for bone-sample selection for nuclear DNA analysis in a forensic context. The procurement of small, primarily cancellous bones with associated soft tissues should be preferentially sampled, and no longer dismissed as potential DNA sources in favor of cortical bone tissue

    Fingermark simulants and their inherent problems: A comparison with latent fingermark deposits

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    Commercially available fingermark simulants werecompared to latent fingermark deposits to assess their efficacy asstandards for a quality control assessment of fingermark developmentreagents. Deposits of the simulants and latent fingermarks were madeon paper substrates and were developed using reagents that targetamino acids (ninhydrin, 1,2-indanedione) and sebaceous secretions(Oil Red O, physical developer). The resulting marks were comparedfor visibility and color. Significant differences were observed betweenthe simulants and latent fingermarks in response to the fingermarkdevelopment reagents. Infrared spectroscopic analysis of the simulantscompared to untreated latent fingermarks revealed differencesin chemical composition. These results indicate that these simulantsare not well suited as quality control standards in forensic laboratoriesand should be used with extreme caution in any form of research intolatent fingermark detection

    Characterisation of chemical component migration in automotive paint by synchrotron infrared imaging

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    Synchrotron infrared chemical imaging was employed to examine and assess the extent of interlayer component migration within multilayer automotive paint samples, with a particular emphasis on the cross-linking additive melamine. Two dimensional infrared chemical images revealed that melamine consistently diffuses in select paint samples from the underlying basecoat into the outermost clear coat layer. Pigments from the basecoat were also found to migrate into the adjoining layers. This is significant as the relative abundance of both melamine and pigments will vary greatly depending upon the region of the layer analysed. This component migration will undoubtedly impact the information gleaned from a questioned sample via library searching software or multivariate statistics. As a result, appropriate analytical protocols will need to be utilised to mitigate the effects of interlayer pigment and melamine diffusion, so as to afford a true representation of the composition of the coating for forensic identification purposes
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