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In this study, DNA extracted from known buccal samples was combined into two component mixture samples. These were subjected to UV exposure prior to their amplification with the Promega PowerPlex® 16HS amplification kit, and subsequent capillary electrophoresis on the ABI 3130xl instrument. Damaged samples were subjected to enzymatic repair treatment and retested to assess the amount of repair. Data showed that there is fidelity associated with the application with profile concordance after its use, and a corresponding increase in the amount of recovered alleles post damage. Results also showed changes in the stochastic relationship between mixture components that appear to be induced by the repair process itself. The mixture ratios of DNA samples were altered from an approximate original 1:3 ratio, to a ratio of 1:2 or greater. This variation can have a significant effect regarding the ability to reliably de-convolute DNA mixtures that have been subjected to the repair process. 相似文献
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Fiber evidence found on a suspect vehicle was the only useful trace to reconstruct the dynamics of the transportation of two corpses. Optical microscopy, UV-Vis microspectrophotometry and infrared analysis were employed to compare fibers recovered in the trunk of a car to those of the blankets composing the wrapping in which the victims had been hidden. A "pseudo-1:1" taping permitted to reconstruct the spatial distribution of the traces and to further strengthen the support to one of the hypotheses. The Likelihood Ratio (LR) was calculated, in order to quantify the support given by forensic evidence to the explanations proposed. A generalization of the Likelihood Ratio equation to cases analogous to this has been derived. Fibers were the only traces that helped in the corroboration of the crime scenario, being absent any DNA, fingerprints and ballistic evidence. 相似文献
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Alex Almeida Chedid BSc Larissa Silva Azevedo PhD Ayla Roberta Borges da Silva Galaço PhD Thiago Rui Casagrande BSc Osvaldo Antonio Serra PhD Marcelo Firmino de Oliveira PhD 《Journal of forensic sciences》2023,68(3):780-789
Currently, SEM-EDS is used to detect gunshot residue (GSR) from the presence of Ba, Pb, and Sb in the sample. However, the development of new nontoxic ammunition (NTA) has prevented conventional metals from being found. In this work, we aim to determine the presence of an inorganic luminescent chemical marker based on rare earth in gunshot residues using the technique of squarewave voltammetry (SWV). After firing, the luminescent complex [(Eu2Zr)(btc)3(Hbtc)0.5.6H2O], which is used as a chemical marker, can be detected under a UV lamp. An aqueous solution with 0.1 mol L−1 KCl as supporting electrolyte can be easily collected on carbon paste electrode surfaces for SWV analysis A = 100 mV, f = 10 Hz, and step potential of 5 mV are required. The luminescent marker incorporated into the carbon paste electrode showed two anodic peak currents in the region of 0.4 V (vs Ag/AgCl) and at 0.75 V (vs Ag/AgCl) and also a cathodic one in 0.4 V (vs Ag/AgCl). SEM-EDS was able to analyze the same voltammetric results for conventional and nontoxic ammunition containing the luminescent marker. Therefore, voltammetry and SEM-EDS are valid for detecting the new residue marker in GSR. Despite this, the electrochemical method is still more advantageous because of its low cost and lack of expensive equipment and supplies in forensic laboratories. 相似文献
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Job stress is a pervasive problem for employers in the 21st century economy, making it a timely and important topic in organizational settings. The variables influencing job stress are numerous and consequently it may be analyzed from different perspectives, but the root is primarily physical and psychosocial. This study specifically explores three physical sources of job stress—contractual condition of work, organizational position, and dimension of organization—and of one psychosocial source—work conflict. A survey instrument was used to collect information from regional Public Administration employees of South Italy. Data from 1,130 respondents were analyzed. Statistical correlations and hierarchical regression showed that contractual condition of work, organizational position, organizational dimension, and work conflict were all predictive aspects of job stress. 相似文献