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101.
R.S. Corrêa V.F. Melo G.G.F. Abreu M.H. Sousa J.A. Chaker J.A. Gomes 《Science & justice》2018,58(2):138-144
Soil traces are useful as forensic evidences because they frequently adhere to individuals and objects associated with crimes and can place or discard a suspect at/from a crime scene. Soil is a mixture of organic and inorganic components and among them soil clay contains signatures that make it reliable as forensic evidence. In this study, we hypothesized that soils can be forensically distinguished through the analysis of their clay fraction alone, and that samples of the same soil type can be consistently distinguished according to the distance they were collected from each other. To test these hypotheses 16 Oxisol samples were collected at distances of between 2 m and 1.000 m, and 16 Inceptisol samples were collected at distances of between 2 m and 300 m from each other. Clay fractions were extracted from soil samples and analyzed for hyperspectral color reflectance (HSI), X-ray diffraction crystallographic (XRD), and for contents of iron oxides, kaolinite and gibbsite. The dataset was submitted to multivariate analysis and results were from 65% to 100% effective to distinguish between samples from the two soil types. Both soil types could be consistently distinguished for forensic purposes according to the distance that samples were collected from each other: 1000 m for Oxisol and 10 m for Inceptisol. Clay color and XRD analysis were the most effective techniques to distinguish clay samples, and Inceptisol samples were more easily distinguished than Oxisol samples. Soil forensics seems a promising field for soil scientists as soil clay can be useful as forensic evidence by using routine analytical techniques from soil science. 相似文献
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103.
目的对研制的二乙酰吗啡盐酸盐标准物质进行定值,并评定定值结果的不确定度。方法采用定量核磁共振法和质量平衡法进行定值;采用液质联用法用于有机物杂质的定性分析,采用电感耦合等离子质谱法、离子色谱法、顶空-气质联用法和卡尔费休滴定法测定无机阳离子、阴离子、挥发性有机溶剂残留和水分等杂质的含量。结果定量核磁共振法的纯度为95.6%,不确定度为0.13%;质量平衡法的纯度为95.3%,不确定度为0.93%。结论二乙酰吗啡盐酸盐标准物质的纯度值为95.6%,扩展不确定度为1.2%(k=2)。 相似文献
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106.
Géraldine Maujean M.D. Tiphaine Guinet M.D. Laurent Fanton Ph.D. Daniel Malicier Ph.D. 《Journal of forensic sciences》2013,58(4):1069-1070
A 27‐year‐old man was found dead in an advanced decomposition stage at home. On external examination, his body showed petechial hemorrhages of the skin. At autopsy, petechial hemorrhages of the epicardium were found, but no sign of meningitis was detected. Toxicological investigations remained negative. Bacteriological conventional analyses showed no significant result. Neisseria meningitidis serogroup B was finally isolated on cerebrospinal fluid by a specific real‐time polymerase chain reaction. To our knowledge, there are no available data about the postmortem diagnosis of an infectious cause of death in a decomposed corpse. In such situations, the polymicrobial overgrowth usually hampers the interpretation of bacteriological conventional methods and questions their diagnostic value. Such molecular bacteriological approaches appear to constitute an important diagnostic tool for forensic scientists and should be widely processed in case of suspected infectious death or sudden death whatever the postmortem interval. 相似文献
107.
Abstract: The American Academy of Pediatrics’ Committee on Child Abuse and Neglect, Section on Ophthalmology, acknowledges that searching for retinal hemorrhages (RHs) in infants only in cases of suspected of abuse creates selection bias. However, they also recommend that postmortem eye removal might not be indicated “in children who have clearly died from witnessed severe accidental head trauma or otherwise readily diagnosed systemic medical conditions.” Although infrequently described in the child abuse literature, peripapillary intrascleral hemorrhages (bleeding in the sclera at the optic nerve insertion)—putatively from severe repetitive acceleration/deceleration forces with or without blunt head trauma—have been considered essentially pathognomonic for abusive head trauma (shaken baby syndrome). We present two neonates who sustained accidental, severe in utero head injuries and had associated extensive RHs and optic nerve sheath hemorrhages with peripapillary intrascleral hemorrhages detected at autopsy. Neither neonate had a documented clinical fundal examination in the intensive care unit. 相似文献
108.
Matthew R. Lockett Ph.D. Katherine A. Mirica Ph.D. Charles R. Mace Ph.D. Robert D. Blackledge M.S. George M. Whitesides Ph.D. 《Journal of forensic sciences》2013,58(1):40-45
This paper describes a method for determining the density of contact trace objects with magnetic levitation (MagLev). MagLev measurements accurately determine the density (±0.0002 g/cm3) of a diamagnetic object and are compatible with objects that are nonuniform in shape and size. The MagLev device (composed of two permanent magnets with like poles facing) and the method described provide a means of accurately determining the density of trace objects. This method is inexpensive, rapid, and verifiable and provides numerical values—independent of the specific apparatus or analyst—that correspond to the absolute density of the sample that may be entered into a searchable database. We discuss the feasibility of MagLev as a possible means of characterizing forensic‐related evidence and demonstrate the ability of MagLev to (i) determine the density of samples of glitter and gunpowder, (ii) separate glitter particles of different densities, and (iii) determine the density of a glitter sample that was removed from a complex sample matrix. 相似文献
109.
Forensic determination of hair deposition time in crime scenes using electron paramagnetic resonance
Nikhita Shankar MS André O. Guimarães PhD Eleonora Napoli PhD Cecilia Giulivi MS PhD 《Journal of forensic sciences》2021,66(1):72-82
Several types of biological samples, including hair strands, are found at crime scenes. Apart from the identification of the value and the contributor of the probative evidence, it is important to prove that the time of shedding of hair belonging to a suspect or victim matches the crime window. To this end, to estimate the ex vivo aging of hair, we evaluated time‐dependent changes in melanin‐derived free radicals in blond, brown, and black hairs by using electron paramagnetic resonance spectroscopy (EPR). Hair strands aged under controlled conditions (humidity 40%, temperature 20–22°C, indirect light, with 12/12 hour of light/darkness cycles) showed a time‐dependent decay of melanin‐derived radicals. The half‐life of eumelanin‐derived radicals in hair under our experimental settings was estimated at 22 ± 2 days whereas that of pheomelanin was about 2 days suggesting better stabilization of unpaired electrons by eumelanin. Taken together, this study provides a reference for future forensic studies on determination of degradation of shed hair in a crime scene by following eumelanin radicals by utilizing the non‐invasive, non‐destructive, and highly specific EPR technique. 相似文献
110.
Stephan A. Bolliger M.D. ; Lars Oesterhelweg M.D. ; Danny Spendlove M.D. ; Steffen Ross M.D. ; Michael J. Thali M.D. 《Journal of forensic sciences》2009,54(5):1119-1122
Abstract: The radiological determination of foreign objects in corpses can be difficult if they are fragmented or deformed. With multislice computed tomography, radiodensities—referred to as Hounsfield units (HU)—can be measured. We examined the possibility of differentiating 21 frequently occurring foreign bodies, such as metals, rocks, and different manmade materials by virtue of their HU values. Gold, steel, and brass showed mean HU values of 30671–30710 (upper measurable limit), mean HU values for steel, silver, copper, and limestone were 20346, 16949, 14033, and 2765, respectively. The group consisting of objects, such as aluminum, tarmac, car front-window glass, and other rocks, displayed mean HU values of 2329–2131 HU. The mean HU value of bottle glass and car side-window glass was 2088, whereas windowpane glass was 493. HU value determination may therefore help in preautopsy differentiation between case-relevant and irrelevant foreign bodies and thus be useful for autopsy planning and extraction of the objects in question. 相似文献