Polymerase slippage in relation to the uniformity of tetrameric repeat stretches

The aim of the study was to test the hypothesis that polymerase slippage correlates to the length of repeat stretches consisting of uniform repeats against the alternative hypothesis that the total number of repeats is most relevant. Two short tetrameric short tandem repeats (STRs) with different repeat structures were investigated: D3S1545 containing only homogeneous (GATA)n repeat stretches and D7S1517 with compound repeat arrays of GAAA and CAAA repeats. Additionally two different polymerases (Herculase and AmpliTaq Gold) were used which gave comparable results. No correlation was found for the hypothesis "total repeat number against percent of stutter"; in contrast, the other hypothesis that the number of uniform repeats is relevant for the degree of stutter gave a strong positive correlation (0.82 for selected D7S1517 alleles) which confirmed the hypothesis that polymerase slippage correlates to the length of repeat stretches consisting of uniform repeats.     

Explaining Regulatory Non-compliance: A Survey Study of Rule Transgression for Two Dutch Instrumental Laws, Applying the Randomized Response Method

Within a rational choice framework, secondary data analysis of a survey study on compliance with two Dutch regulatory laws is carried out. Selection of explanatory variables to be considered is guided by a heuristic device, called the Table-of-Eleven. Using adapted logistic regression analysis, we show that self-reported compliance, measured by means of a randomized response procedure, can be explained in terms of benefits of non-compliance, social norms and deterrence, while knowledge and general norm-conformity have no role to play. The impact of various contributing factors turns out to be rather different in size for the two laws.     

Classification of premium and regular gasoline by gas chromatography/mass spectrometry,principal component analysis and artificial neural networks

Detection and correct classification of gasoline is important for both arson and fuel spill investigation. Principal component analysis (PCA) was used to classify premium and regular gasolines from gas chromatography-mass spectrometry (GC-MS) spectral data obtained from gasoline sold in Canada over one calendar year. Depending upon the dataset used for training and tests, around 80-93% of the samples were correctly classified as either premium or regular gasoline using the Mahalanobis distances calculated from the principal components scores. Only 48-62% of the samples were correctly classified when the premium and regular gasoline samples were divided further into their winter/summer sub-groups. Artificial neural networks (ANNs) were trained to recognise premium and regular gasolines from the same GC-MS data. The best-performing ANN correctly identified all samples as either a premium or regular grade. Approximately 97% of the premium and regular samples were correctly classified according to their winter or summer sub-group.     

Area-specific increased density of mu-opioid receptor immunoreactive neurons in the cerebral cortex of drug-related fatalities

In animal experiments and in cell culture, chronic morphine treatment has been followed by "up-regulation" as well as "down-regulation" of the mu-opioid receptor (OR) number. The present postmortem morphometric study of morphine-related fatalities of drug-addicts (n=13, 20-35 years old, with blood unconjugated morphine levels from 27.1 ng/ml to 458 ng/ml, m.v. 198.5 ng/ml) versus a non-addicted control group (n=13, 10-44 years old) was intended to examine, whether chronic opiate exposure affects the numerical density of mu-OR expressing neurons in the human neocortex (areas 11, 24 and 25 according to Brodmann). For the immunohistochemical procedure, vibratome sections (100 microm) were incubated with a monoclonal antibody against the mu-OR, diluted 1:100, and immunolabelled sites were visualized using an immunoperoxidase protocol. The numerical densities of OR immunoreactive neuronal profiles and Nissl-stained central profiles were assessed morphometrically (camera lucida-drawings). In both groups, the anti-mu-OR-immunoreactivity was mainly localized in pyramidal neurons of layers (L) II/III and V and in multiform neurons of L VI. In the areas 24 and 25, the density of the immunoreactive neuronal profiles did not display a significant difference between the two examined groups. In the area 11, however, the number of immunolabelled neuronal profiles amounted to 2777+/-206 mm(3) in the drug-related fatalities and to 2320+/-124 mm(3) in the control group and thus was significantly increased.     

Analysis of 1989-1999 homicide crimes in the catchment area of the Bonn Institute of Forensic Medicine with reference to selected aspects

195 cases of homicide, grouped according to juridical assessment, were retrospectively analysed with regard to individual characteristics of perpetrators and victims, circumstances, and mode of commitment. The involvement of underage victims and perpetrators as well as differences between the urban and rural areas studied were taken into special consideration. To summarise, the majority of the offences studied was carried out by a male perpetrator with a mean age of 35 years driven by personal motives or greed in his immediate vicinity and affected family members or close acquaintances. The fatal injuries were mainly attributable to sharp or blunt force. With regard to killings of children, a higher prevalence of female victims and male assailants, emotional motives and an even higher importance of the social vicinity were found. Particularly in victims younger 12 years of age, manual modes of commitment without application of any tools were predominantly encountered. The comparison of urban and rural areas revealed a higher homicide rate in municipal areas especially of offences with a loose relationship between victims and assailants (greed, sexual assault). In contrast, rural areas exhibited higher rates of bodily harm with fatal consequences as well as offences by highly intoxicated assailants.     

An alternative method to screen for pepper spray residue

A method was developed to screen for pepper spray residue using instruments and methods other than those techniques commonly employed to analyze chemical residue (i.e.. gas chromatography mass spectrometry-GCMS or liquid chromatography mass spectrometry-LCMS). The method employed gas chromatography (GC), thin layer chromatography (TLC), and diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) to screen for dried pepper spray stains. Pepper sprays from nine different manufacturers were investigated. Capsaicin and dihydrocapsaicin were identified and unique IR reflectance spectra are presented. An additional five compounds were presumptively found. Results showed that a particular stain could be characterized as a pepper-based stain.     

Virtopsy-postmortem multislice computed tomography (MSCT) and magnetic resonance imaging (MRI) in a fatal scuba diving incident

The body of a 44-year-old scuba diver was examined using postmortem multislice computed tomography (MSCT) and magnetic resonance imaging (MRI), and findings were verified by subsequent autopsy. The goal was to find out whether the important pathomorphological findings for the reconstruction of events and the identification of cause and manner of death could be identified using modem digital cross-sectioning techniques. The findings of a massive vital decompression with pulmonary barotrauma and lethal gas embolism were identified in the radiological images. MSCT and MRI were superior to autopsy in the demonstration of the extent and distribution of gas accumulation in intraparenchymal blood vessels of internal organs as well as in areas of the body inaccessible by standard autopsy.     

Further studies on spot tests and microcrystal tests for identification of cocaine

The presence of cocaine in illicit drug samples is still being determined in some laboratories using spot tests and microcrystal tests. Seventeen chemical species were tested using three different spot tests (Wagner, Marquis, and cobalt thiocyanate followed by stannous chloride reactions) and two microcrystal tests (gold chloride and platinic chloride) to determine whether the results could be differentiated from the results of these tests on cocaine. The data obtained indicated that nine of the 17 compounds gave results similar to those from cocaine using the three spot tests, but that the results from microcrystal testing allowed for differentiation of all nine compounds from cocaine.