SDS gel capillary electrophoresis (Beckman-Coulter ProteomeLab) and the lab-on-a-chip technology (Agilent 2100 Bioanalyzer) were used to quantify the relative amount of 7S and 11S fractions in twenty different soybean cultivars. The better repeatability of the migration times and peak areas was achieved for the Bioanalyzer. Both lab-on-a-chip instrument and a traditional capillary gel electrophoresis were shown to be adequate for analysis of soy-based products. Integrating the area of peaks within a certain range of molecular weights was used to calculate the relative content of each protein subunit. Poor agreement in the classification in the protein subunit groups between the two instruments was observed. Therefore, the approach of visual identification taking into account both the variability in the position of the peaks and the detection of different number of peaks between the profiles was applied. This resulted in statistically significant correlation being observed between 11S ⁄ 7S ratios determined by Bioanalyzer and ProteomeLab (R = 0.82). The reported differences in 11S and 7S content between the studies are likely to be affected by the differences in the techniques used to analyse soy protein subunits. A brief presentation of the chemometric analysis of electrophoretic profiles as a common method for transforming electrophoretograms to multivariate data sets is shown.
A logger enabling continuous measurement of corrosion rate of selected metals in indoor and outdoor atmospheres has been developed. Principle of the measurement method is based on the increasing electrical resistance of a measuring element made of the material concerned as its cross-sectional area diminishes due to corrosion. Zinc, iron, copper and nickel sensors at several thicknesses are available. Sensitivity of the corrosion measurement varies from 1 to 10 nm depending on the type and thickness of the sensor. Changes in the air corrosivity can be thus detected within hours or even tens of minutes. The logger lifetime in medium corrosive environments is designed to be 2 years with full autonomy. Data on the sensor corrosion rate are available any time through GPRS connection or by a non-contact inductive reading without the need of retracting the logger from the exposure site.
A review is given of the conventional methods of determining the age of blood stains by forensic examination of trace evidence. Detailed analysis of the samples in several steps, which destroyed the traces, and the widely differing results do not appear satisfactory with regard to their use in forensic investigations. Considering the change in color with increasing age the three coloric parameters (chroma, hue, and value of the blood stain) can yield exact numerical measurements which allow to draw relatively reliable conclusions as to the age of the blood stain. Of the three colorimetric methods, based on equalization, three regions, and spectral analysis, respectively, only the last may be considered really satisfactory and up to the requirements of forensic medicine. It has the additional advantage of being independent of the visual acuity of the examiner and of the type and quality of the source of illumination. The aging of freshly taken venous blood, which has been deposited on filter paper or linen, can last up to 33 days, either in the dark or in day light, with due regard to temperature and humidity. The spectrophotometric color measurements taken place on the immediate surface of the blood stain in the range of the visual spectrum between 400 and 600 nm. The continuously drawn spectral curves are then subject to remission analysis the first step. The second step consists in a mathematical computer analysis of color valence measurements.
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