PubMed · 3304010
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T A Brettell, R Saferstein. 1987-06-15. Forensic science.. https://doi.org/10.1021/ac00139a010
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Gunshot residues originating from six types of pistol ammunition were studied. Six persons who normally have no contact with weapons fired three times, each person from a different pistol. Samples of gunshot residues were collected from the shooters' hands using aluminium stubs with black carbon adhesive tabs and subjected to examinations of their morphology and elemental content by means of a scanning electron microscope with an energy dispersive X-ray spectrometer in an automatic manner. In a comparative study of the samples, only primer residues were taken into account. The frequency of occurrence of particles representing a certain chemical class against the total number of detected particles was expressed as a percentage. Mutual relations between the frequencies of occurrence of the residues of particular chemical content were found to be different for most of the studied ammunition types using a non-statistical approach--and by means of non-parametric statistical methods (R-Spearman and tau-Kendall correlation coefficients), it was possible to differentiate one ammunition type from each of the other ammunition types examined. The performed examinations have revealed some differences in the frequencies of occurrence of certain chemical classes of primer residues, observed for various types of ammunition. These differences could constitute a valuable contribution to group identifications of ammunition made on the basis of physical and chemical examinations of gunshot residues.
We describe a minisequencing protocol for screening DNA samples for the presence of 12 mutations in the human melanocortin 1 receptor gene (MC1R), eight of which are associated with the red hair phenotype. A minisequencing profile which shows homozygosity for one of these mutations or the presence of two different mutations would strongly indicate that the sample donor is red haired. The absence of any red hair causing mutations would indicate that the sample donor does not have red hair. We report the frequencies of MC1R variants in the British red haired population.
The validity of the determination of particle size distribution for forensic soil identification was studied using 73 soil samples collected from a 20 km x 15 km area. Soil particles were first divided into two fractions by wet sieving with a sieve with a 0.05 mm aperture size. Dry sieving was used to analyze the coarse particle fraction and a particle size analyzer was used for the fine particle fraction. The number of particle size classes measured by sieving could be reduced to three, <0.05, 0.05-0.2, and 0.2-2 mm, which enabled 87.9% of the soil samples to be discriminated. Measurements made with the particle size analyzer on the fine particle fraction increased the discriminating power to 95.9%. The use of particle size analysis by sieving in combination with color examination allowed us to discriminate 99.5% of the soil samples, even when particle size analysis of the fine particle fraction was not carried out.