Microscopic characteristics of hacking trauma

The purpose of this study was to determine if it is possible to associate machetes, axes, and cleavers with the microscopic parallel striations they leave on the cut surfaces of the bone. Hacking trauma was experimentally inflicted on pig bones using machetes, axes, and cleavers. Negative impressions of both the cut surfaces of the bone and the weapon blades were analyzed using scanning electron microscopy. The results of this investigation indicate that it is possible to correlate a class of hacking weapons to trauma inflicted on bone by these weapons.     

Processes involved in the development of latent fingerprints using the cyanoacrylate fuming method

Chemical processes involved in the development of latent fingerprints using the cyanoacrylate fuming method have been studied. Two major types of latent prints have been investigated-clean and oily prints. Scanning electron microscopy (SEM) has been used as a tool for determining the morphology of the polymer developed separately on clean and oily prints after cyanoacrylate fuming. A correlation between the chemical composition of an aged latent fingerprint, prior to development, and the quality of a developed fingerprint has been observed in the morphology. The moisture in the print prior to fuming has been found to be more important than the moisture in the air during fuming for the development of a useful latent print. In addition, the amount of time required to develop a high quality latent print has been found to be within 2 min. The cyanoacrylate polymerization process is extremely rapid. When heat is used to accelerate the fuming process, typically a period of 2 min is required to develop the print. The optimum development time depends upon the concentration of cyanoacrylate vapors within the enclosure.     

NIST mixed stain studies #1 and #2: interlaboratory comparison of DNA quantification practice and short tandem repeat multiplex performance with multiple-source samples

The Mixed Stain Study 1 (MSS1, Apr.-Nov. 1997) and Mixed Stain Study 2 (MSS2, Jan.-May 1999) evaluated multiplexed short-tandem repeat (STR) DNA typing systems with samples containing DNA from more than one source. These interlaboratory challenge studies evaluated forensic STR measurement, interpretation, and reporting practice using well-characterized samples of very different analytical difficulty. None of the relatively few errors reported in either exercise resulted in a false identification of a reference source; several errors in evaluating the unknown source in three-source samples would hinder matching the profile in any archival database. None of the measurement anomalies reported is associated with any particular STR multiplex; all DNA amplification anomalies are associated with inefficient DNA extraction, inaccurate DNA quantitation, and/or analytical threshold policies.     

Status and prospects of developing the Forensic Medical Service in the Russian Federation

Forensic medical service is constantly updated, which is confirmed by introduction of new modern methods, such as detection of blood or semen with test strips, new modifications of methods for handling bone material, differentiation of blood of the same group within ABO system, identification of blood groups in mixed stains of blood of humans and some animals, use of gel plates, etc. Methodological and information letters have been issued and field seminars are regularly carried for upgrading expert biologists. The overwhelming majority of expert biologists have received specialized education and topical upgrading.     

Complex chemical and toxicological analysis of prosidol

Methods for measuring a Russian narcotic analgesic prosidol are suggested: thin-layer chromatography, microcrystalloscopy, gaseous chromatography with ionization flame detector, gas chromatography with mass selective detector, ultraviolet spectroscopy, high-performance liquid chromatography with ultraviolet detector, proton nuclear magnetic resonance used in chemical toxicological analysis, pharmacological analysis, and investigation of material evidence pieces.     

Forensic chemical testing of cadaveric material for acetonitrile

Gas chromatographic conditions for qualitative and quantitative evaluation of acetonitrile in biological material were determined, including those for reactive gas chromatography. Absolute and relative time of acetonitrile and concomitant substances retention in three columns of different polarity was determined. Study of the time of acetonitrile retention in biological material showed that acetonitrile concentration in the blood virtually did not change in cadaveric material stored in a hermetically closed flask for 2 weeks at 20 +/- 3 degrees C, while its concentration in the stomach decreased by 10-15%. Distribution of acetonitrile in human viscera in lethal poisoning was studied; the agent was evenly distributed in the gastric wall, intestine, liver, and kidney, while its concentrations in the lung and brain were 2-3 times higher. Forensic chemical expert analyses of the blood, urine, and viscera from corpses of humans dead from lethal acetonitrile poisoning showed that lethal concentration in the blood was 28.3-57.0 mg and in the urine 23.2-40.6 mg/100 ml.