Dietary health does affect histological age assessment: an evaluation of the Stout and Paine (1992) age estimation equation using secondary osteons from the rib

An age at death estimation equation that uses rib histological variables presented by Stout and Paine was used to evaluate a skeletal population of individuals with a known age at death and cause of death from either malnutrition or the niacin deficiency disease pellagra. The sample was comprised of 26 autopsied black South Africans. Histological analysis of mounted thin sections involved the microscopic measurement of cortical area and a count of the number of intact and fragmentary secondary osteons for the entire cross-section of the rib. Rib osteon population density values were then calculated for each case. It was found that this equation under-aged individuals on average by 29.2 years. Overall, secondary osteon size and Haversian canals tended to be larger than expected, while cortical bone area was less when compared with a control population. The implications of these findings are critical given that many of the skeletal remains examined by forensic anthropologists come from marginalized backgrounds, including malnutrition. This research suggests that measurements based on healthy cases may not be useful in an analysis of individuals with poor diet and health. It is argued that new standards for histological age assessment methods need to be created that account for variation in the health status of individuals examined by forensic anthropologists.     

Taphonomy of child-sized remains: a study of scattering and scavenging in Virginia, USA

Child-sized pig carcasses (Sus scrofa) were placed in surface deposit and buried scenarios in a wooded area of Virginia from May 1998 through December 2000, to examine the taphonomic effects of decompositional changes, predator scavenging, and the extent of remains scattering. Changes were observed through on-site examination, charting of remains, and recorded video imaging. Analysis of data revealed that utilization of corpses as food sources by vertebrates was dependent upon invertebrate colonization. Vertebrates avoided feeding on the corpses while invertebrate colonization was active, and would feed before invertebrates successfully colonized a corpse, or would wait until the invertebrate populations migrated away from the corpse. Among vertebrates, there was no apparent succession order for the animals utilizing the remains as a food source. Different vertebrates would feed at different times based upon diurnal or nocturnal predilection. Analysis noted an accidental cooperative relationship between the invertebrates and vertebrates scavenging on the corpses. Certain vertebrates gained access to the internal tissues by utilizing openings in the corpses caused by invertebrate and other vertebrate scavenging. Alternately, carrion-frequenting insects were afforded access to previously inaccessible colonization sites as a result of scavenging vertebrate activities.     

Influence of substrate tissue type on larval growth in Calliphora augur and Lucilia cuprina (Diptera: Calliphoridae)

The size of fly larvae is an important variable in the use of these insects to estimate postmortem interval. Furthermore, the nutritional intake of larvae is likely to vary subject to the part of a corpse on which they are feeding. A study was therefore conducted to investigate the effect of type of food substrate on larval growth in two species of forensically important Australian blowflies. After collection on sheep's liver in the laboratory, different groups of larvae of Lucilia cuprina (Wiedemann) and Calliphora augur (Fabricius) were grown on sheep's liver, meat, and brains, and their body lengths compared. Results indicated that the development of larvae fed sheep's liver was adversely affected compared with larvae fed meat and brain; they moulted later, reached maximum length more slowly and sometimes produced significantly smaller pupae. These findings, similar to those of another recent study, have obvious implications for postmortem interval determinations. Estimates may be considerably skewed if the site of collection of larvae at a death scene contains tissue types different to those used in reference experiments. We therefore recommend caution in forensic analyses that interpret crime scene data using developmental studies performed with a single type of larval food substrate.     

Lead-free primer residues: a qualitative characterization of Winchester WinClean, Remington/UMC LeadLess, Federal BallistiClean, and Speer Lawman CleanFire handgun ammunition

The elemental composition and postfiring residues of several "lead-free" or "nontoxic" centerfire handgun ammunition types currently available to the general public were examined. Offerings from Winchester, Remington/UMC, Federal and Speer were obtained from retail sources in both .45 ACP and 9 mm when possible. A total of 112 postfiring residue samples (SEM pins) were collected at varying distances from the muzzle, at two distances from target and from the shooter's hands. An additional 20 samples were collected by direct ignition of primers. Qualitative determinations were carried out using scanning electron microscopy (SEM)/electron dispersive spectrometry (EDS) analysis. All types tested contained aluminum (Al), silicon (Si), copper (Cu), and zinc (Zn). Most contain traces of sulfur and calcium. Winchester WinClean and Remington LeadLess contained potassium as the principle ingredient. Federal BallistClean contained barium, while Speer Lawman CleanFire contained strontium. In the main, these compared favorably with manufacturers' MSDS publications and patents granted. The characterizations undertaken here will be of use to the forensic electron microscopist as these formulations gain popularity.     

A forensic case study of a naturally mummified brain from the bushveld of South Africa

The present study reports our observations of a naturally mummified human brain found in the bushveld of South Africa. This case extends the geographic and climatic ranges in which mummified brains have been found, and it represents an additional case where no human activity has led to the mummification. The mummified brain was c. one fifth the size of a normal human brain, while the gyral and sulcal patterns of a typical human brain were clear. CT scanning of the brain revealed that subcortical structures, normally evident in this type of imaging, were not discernable, indicating a slow mummification process. Histological examination of the tissue revealed near complete degradation of the microanatomical structure, with only putative Nissl bodies remaining as identifiable neural microstructures. The specimen appears to have survived several veld fires, as well as a high annual rainfall, and a high relative humidity. It is thought that specific conditions amenable to brain mummification, but not other soft tissues, occurred in the skull of this specimen in the weeks postmortem.     

Forensic analysis of bicomponent fibers using infrared chemical imaging

The application of infrared chemical imaging to the analysis of bicomponent fibers was evaluated. Eleven nominally bicomponent fibers were examined either side-on or in cross-section. In six of the 11 samples, infrared chemical imaging was able to spatially resolve two spectroscopically distinct regions when the fibers were examined side-on. As well as yielding characteristic infrared spectra of each component, the technique also provided images that clearly illustrated the side-by-side configuration of these components in the fiber. In one case it was possible to prepare and image a cross-section of the fiber, but in general the preparation of fiber cross-sections proved very difficult. In five of the 11 samples, the infrared spectra could be used to identify the overall chemical composition of the fibers, according to a published classification scheme, but the fiber components could not be spatially resolved. Difficulties that are inherent to conventional "single-point" infrared spectroscopy, such as interference fringing and sloping baselines, particularly when analyzing acrylic type fibers, were also encountered in the infrared chemical image analysis of bicomponent fibers. A number of infrared sampling techniques were investigated to overcome these problems, and recommendations for the best sampling technique are given. Chemical imaging results were compared with those obtained using conventional fiber microscopy techniques.     

An evaluation of matching unknown writing inks with the United States International Ink Library

Utilizing a database of standards for forensic casework is a valuable resource. Undoubtedly, as more standards (and corresponding information about the specimens) are collected, there is a greater certainty of identification when a questioned and a known item cannot be distinguished after a series of analyses. The United States Secret Service and the Internal Revenue Service National Forensic Laboratory jointly maintain the largest known forensic collection of writing inks in the world, which is comprised of over 8500 ink standards collected worldwide, dating back to the 1920s. This study was conducted to evaluate the reliability of matching arbitrarily purchased pens with known inks from a database. One hundred pens were randomly obtained from a variety of sources and their respective ink compositions were compared with standards. Eighty-five of the inks were determined to be suitable for comparison utilizing optical examinations and thin-layer chromatography. Three of the inks did not match any of the specimens on record; one of these inks was similar to an ink from an identical brand of pen that was in the database, but had a modified formulation.     

Use of diagonal teeth measurements in predicting gender in a Turkish population

Mesiodistal and buccolingual measurements, commonly used as a means of sex determination from teeth, can sometimes cause difficulties. The aim of this study is to test whether diagonal measurements can make it possible to take more accurate measurements. The results of diagonal measurements of dental casts taken from 30 males and 30 females have been evaluated by discriminant function statistics. Intra- and interobserver error tests did not indicate any statistically significant differences between the findings of two observers. Seven of the 14 measurements on the maxilla and 10 of the 14 measurements on the mandible have been found to be significantly greater in males. According to the results of the stepwise discriminant function statistics, the most contributory measurements to the function were upper first incisor mesiobuccal-distolingual (MBDL) and distobuccal-mesiolingual, lower second incisor MBDL, and lower canine MBDL. The highest reliability was obtained in MBDL measurements. It was realized that diagonal measurements of teeth, especially of canines, revealed clear dimorphic differences. Classification accuracy was found to be 83.3% for total sample, 78.3 for upper jaw, and 85.0% for the lower jaw. Accuracy rate was higher in the lower teeth. Commonly seen orthodontic anomalies, such as tooth rotations, crowding, attritions, deep dentin-enamel junction defects, and certain types of fillings, could make it difficult to correctly take width measurements or could cause other mistakes to occur. This explains the reason why this research has been considered to be of some use in diagonal measurements, which is an accurate method, particularly when employed for the front teeth.     

Classification of black powder toners on the basis of integrated analytical information provided by Fourier transform infrared spectrometry and X-ray fluorescence spectrometry

Differentiating between black powder toners used in laser printers and copiers can be challenging for forensic examiners. One hundred and sixty-two samples from 82 different types of cartridges produced by 21 manufacturers that are currently available on the Polish market were studied using Fourier transform infrared spectrometry (FT-IR) and energy-dispersive X-ray fluorescence spectrometry (XRF). The spectra obtained by these two methods were classified into 14 groups and 28 groups using FT-IR and XRF, respectively. These classifications served as a basis for the development of an analytical scheme for differentiating black powder toners. This scheme can be used with any two methods that supply different information about an examined sample. The research will show that if two samples are similar in polymer composition (e.g., FT-IR spectra), additional quantitative elemental composition from XRF analyses may provide more discrimination. It was possible to differentiate 82.5% pairs of examined samples using only FT-IR, 90.8% pairs of examined samples using only XRF, and 95.8% pairs of examined samples using these two methods. Obtained spectra and all the available information could be used to create/build a database. The results obtained confirm the multiplicity and compatibility of toners. Additionally, it was stated that not all the samples were original (OEM).