Limitations of ZAF correction factors in the determination of calcium/phosphorus ratios: important forensic science considerations relevant to the analysis of bone fragments using scanning electron microscopy and energy-dispersive x-ray microanalysis

A series of calcium phosphate standards having calcium/phosphorus (Ca/P) molar ratios of 0.50, 1.00, 1.50, and 1.67, respectively, was prepared for bulk specimen analysis using scanning electron microscopy (SEM) and energy-dispersive X-ray microanalysis (EDXA). The standards were mounted on carbon planchettes as either pure crystals or crystals embedded in epoxy resin. Ten different samples of each embedded and non-embedded standard were analyzed in a JEOL 100 CX electron microscope interfaced with a Kevex 8000 EDXA system using a lithium-drifted silicon detector and a multichannel analyzer. The Ca/P ratios were determined by calculating both net peak intensities without matrix corrections and atomic kappa-ratios using the MAGIC V computer program with ZAF correction factors for quantitative analysis. There was such extensive absorption of phosphorus X-rays in standards embedded in an epoxy matrix that the observed Ca/P ratios were statistically compatible with four different standards ranging in theoretical Ca/P ratios from 1.0 to 1.67. Although the non-embedded crystals showed a greater separation in the Ca/P ratios, both methods of preparation produced serious flaws in analysis. Direct application of the discovery of this caveat to the identification of suspected bone fragments for forensic science purposes is discussed.     

Atypical "body packing syndrome"--a case report

A case of ingested cocaine is reported in which death must be classified as body packer syndrome although both the temporal relationship and the number of packets were atypical. The deceased, a consumer of hard drugs who smuggled for his own use, was found in his flat. He was resuscitated and survived for another four days in hospital. Only four intact drug packages were found in the upper gastro-intestinal tract. The concentrations of cocaine in blood and organs were relatively low but in a potentially lethal range. The case is presented, and its particularities as well as the option of induced vomiting as a way of preventing the fatal outcome are discussed.     

Legal perceptions of forensic DNA profiling part I: a review of the legal literature

A forensic biologist is usually involved in the criminal justice system process somewhere between the police and the legal system, interacting in a practical context regularly and extensively with both. Forensic DNA research and development commonly involves initiatives that encroach into the neighbouring domains of the law enforcement or legal agencies. Despite this level of association, establishing meaningful cross-disciplinary communication and understanding within the justice system remains a challenge. As an example, there is an abundance of literature relating to forensic DNA profiling in legal and criminological periodicals. Such journals are perhaps outside the regular reading of forensic scientists and much of the legal discussion appears to go unnoticed. This situation is understandable; however, it is also undesirable particularly as forensic DNA developments are intertwined with significant changes in legislation and contentious issues of privacy, civil liberty and social justice. This paper attempts to address this shortcoming directly by summarising - from the viewpoint of a forensic scientist - some of the discussion in the legal literature. In particular the review focuses on discussion raising ideological and ethical concerns. Awareness of these views is of relevance to forensic science. It assists us to accurately place DNA evidence into context and to develop its role in achieving the broader criminal justice system objectives. Understanding the discussion also provides a way to enter the debate and communicate at an appropriate level the true potential of DNA to the legal community.