法医学研究杂志

Objectives: The study of transverse dimensions of long bones of the limbs provides valuable information of the human aging process and is of importance in forensic and anthropological sciences. The aim of the present study was to introduce a method to assess age-related adaptive changes in transverse dimensions of lower-limb bones employing a combined osteometric analysis as a different approach for age prediction in adults.

Material and methods: Twenty-four individuals (13 females and 11 males) aged from 22 to 65 years old were enrolled in the study. The mediolateral diameter of the tibia and fibula of the right leg at the one-third distal site was determined by conventional radiographs. An X-ray system model GE XR6000 (GE Hualun Medical Systems Co Ltd., Beijing, China) was used to obtain the radiographic images. Changes in bone dimensions were evaluated by regression and correlation analysis. The StatMate 2.0® software (GraphPad Software Inc., La Jolla, CA, USA) was used for the statistical analysis, with a significance level of 5% (p<0.05). Cohen’s d effect of size parameter was employed to estimate the effect of size on the statistical analysis.

Results: The plot of age as function of the ratio between tibial and fibular dimensions for the entire studied population showed a linear fit slope of (-24.1) year, p=0.0059, and r=0.55, indicating a linear relation of age with the tibia/fibula ratio of mediolateral diameters, regardless of the height or sex of the subject. Distribution analysis of the absolute values of the residuals (actual age-predicted age) gives a median of 7.9 years, with 6.1-10.6 years confidence interval at 95%.

Conclusion: The transverse fibular dimension serves as a normalization factor to compensate for different subjects height and sex when evaluating tibial morphometry. The preliminary data indicate that this method could be an alternative tool for predicting adult age in forensic matters.

Marijuana is the most widespread abused, trafficked, and consumed drug in America. Although according to federal law, the use, consumption, and distribution of marijuana are illegal, approximately two-thirds of the State Governments in the U.S. and the District of Columbia have legalized marijuana for either medical or recreational purposes. Due to the passing of new controversial marijuana legislation at the state levels of government, which started with the passing of Amendments 64 and Initiative 502, respectively, in Colorado and Washington in 2012, the federal government is faced with many challenges associated with enforcing and preventing the illegal diversion of marijuana and marijuana products. Although state legislation may be passed to legalize marijuana for particular jurisdictions, under the Controlled Substances Act (CSA), distribution and possession of marijuana is still illegal on a federal level, and marijuana is classified as a Schedule I controlled substance. Controlling the distribution and trafficking of “legalized marijuana” to minors and improper channels is also a major challenge that law enforcement now faces. However, to date, no extensive registry (chemical nor DNA) or tracking system has been implemented to prevent the diversion of these products to neighbouring states, where the consumption or distribution of these materials remain illegal on the state level. Although the legal requirement in most countries in the identification of marijuana is limited to the confirmation of the presence of cannabinoids (THC) and cystolithic hairs on leaves, several techniques have been published and implemented to investigate the origin of marijuana samples (including palynology, DNA profiling, chemical profiling and isotopic analysis.

In this paper, the chemical complexities of C. sativa L. are presented along with an overview of profiling techniques, which have been proposed for geographical source determination of marijuana. This may provide the forensic community with insight regarding the use of different profiling methods as potential tools in assessing the identification and origin of cannabis samples to support interdiction efforts. Additionally, this study can provide forensic practitioners with relevant information about specificity, discriminatory power, scope, and limitations of different profiling methods for the determination of source origin of marijuana samples. Chemical profiling is proposed as an efficient, robust, and reliable method, which may be a powerful tool for identifying the source of seized Marijuana evidence. Ultimately, chemical profiling techniques may offer forensic laboratories a path forward in establishing links between grow operations, trafficking routes and supply chains, which can ultimately assist in interdiction efforts.

Bloodstain patterns can be used to attempt to sequence events that occurred during a bloodshed event at a crime scene. Perimeter bloodstains may be useful for sequencing as they can indicate movement or the presence of some interacting object between the time that the blood was initially deposited onto its target surface and when it dried completely. The purpose of this series of experiments was to assess the reliability of perimeter bloodstains as an estimation tool for bloodstain drying time as well as to compare the properties of perimeter bloodstains on different target surfaces. After measuring over 600 bloodstains, it was determined that there was a significant difference in the peripheral rim widths of perimeter bloodstains of different drying times under the conditions of this experiment. It was also determined that similar peripheral rim width characteristics are seen on both cardboard and glass surfaces, however, the diameter of the same volume deposited on both surfaces is smaller on cardboard than on glass.

Fingerprint identification is one of the most important methods of solving crimes in the field of forensic science. Forensic scientists and researchers agree that finger prints are individual characteristics that can assist in identifying an individual person from a population. The most challenging duty of a crime scene investigator is to bring suitable finger prints from crime scene to the laboratory. Barriers between surface type, texture of surface, size, shape, contamination, and other multiple factors could be listed as limitations of developing suitable latent finger prints. Undischarged cartridges and discharged cartridge cases are more challenging items for latent finger print processing personnel. Because finger prints are composed of about 98% water, 2% fats (oils) and other components, any latent prints deposited on cartridges prior to being discharged are either burned off from the heat of the discharging, and/or stripped away during extraction as the fire arms goes through the cycle of fire. Human factors, environmental factors and surface area to volume ratio can also play a role in the deposition of latent prints on small sized cartridges and cartridge cases. In this research, we evaluated the dusting methods used for developing latent finger prints from small sized undischarged cartridges and discharged cartridge cases.

We conducted experiments on 143 cartridges and cartridges cases of different calibers and metal alloys in controlled environments by considering different factors. The results showed that no suitable latent finger prints were developed from cartridge cases. Only 5 suitable prints were developed from brass 45 auto undischarged cartridges. Baltimore Police crime laboratory’s call history for 5 past years showed that many thousands of cartridges and cartridge casings were collected from crime scene. However, the numbers of suitable latent fingerprints developed in the past 5 years are not significant. We surveyed Baltimore Police crime laboratory personnel who served as a mobile unit or crime scene science unit technicians, with 1 to 40 years of service experiences and 97% of the responses showed that suitable latent finger prints were not developed via dusting methods from cartridges and cartridge cases. We also extended our questionnaires to 5 randomly selected sister-state laboratories to share their experiences on development of latent finger prints using dusting methods. 2 state laboratories reported that, they do not practice this method on cartridges and cartridge cases at all. The other 2 states reported that they also found out the dusting method as a non-effective method and they are looking for some other method to replace dusting. The 5^th state reported that data was not available to share.

It is commonplace for serious crime offences to be recorded in a three-Dimensional (3D) manner in order to facilitate retrospective analyses of spatial positions of exhibits and objects within a crime scene. The current and most common technique, for capturing these images is via 3D terrestrial laser scanners by forensic personnel. These units provide a highly accurate and detailed record of crime scenes but can be prohibitively expensive for many jurisdictions to adopt. Other scale recordings taken during crime scene examination, such as 3D shoe outsole impressions, require time-consuming digital photography capture or casting to be done.

Photogrammetry is a relatively new technique that is finding utility in a number of forensic capacities, mostly due to its ease of use and adoption of equipment already possessed by crime scene examiners, namely high-quality digital cameras. This research looked to evaluate the use of Agisoft^® Photoscan software for the 3D recording of small-scale crime scenes, along with the detailed capture of 3D outsole impressions. It was found that photogrammetry did have some utility in the recording of entire scenes, albeit potentially only as a tool for the courtroom and jurors. For 3D shoe outsole impressions created in sand, photogrammetry-derived 3D models resulted in -0.73 percent error. This shows promise, with further validation, as a potential replacement to current photographic capture techniques for these exhibits.

Forensic specimens serve as a vital clue in criminal investigation and in efficient administration of justice. The forensic specimens which are highly limited by its quality and quantity require a high throughput analysis to obtain a reproducible result for further action. Preservation of tissue specimen in sodium chloride is suggested for routine forensic DNA analysis. Occasionally, unknowingly the tissue specimens are preserved in formalin in hospitals and forwarded to the laboratory for DNA analysis. The present study demonstrates the effect of formalin and sodium chloride on tissue specimens and their influence on DNA profiling. A comparative study between forensic tissue specimen preserved in formalin and sodium chloride demonstrated that formalin has a negative effect on tissue specimen and significantly affects the outcome of DNA profiling results.