Laser-ablation based spectrochemical Analytical Methods could be used in applications in which the capability for spatially resolved analysis is required. Such analysis gives a 2-D or 3-D map of the monitored chemical elements. Here we introduce automation of a 2-D surface analysis in the laser-induced breakdown spectroscopy setup by implementation of an autofocus algorithm based on the evaluation of the image sharpness. The most suitable algorithm with respect to its speed, accuracy, and durability against digital noise is chosen by testing different gradient-based methods and methods working in the frequency domain.
Author: Liška, M.
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Co-author: Liška, M.
2 articles found
Adam, V. ; Babula, P. ; Beklová, M. ; Galiová, M. ; Havel, L. ; Hubálek, J. ; Kaiser, J. ; Kizek, R. ; Kryštofová, O. ; Liška, M. ; Malina, R. ; Novotný, K. ; Ryant, P. ; Zehnálek, J.
Silver; Heavy metals; Plant biosensor; Sensors; Biochemical marker;
The aim of this work is to investigate sunflower plants response on stress induced by silver(I) ions. The sunflower plants were exposed to silver(I) ions (0, 0.1, 0.5, and 1 mM) for 96 h. Primarily we aimed our attention to observation of basic physiological parameters. We found that the treated plants embodied growth depression, coloured changes and lack root hairs. Using of autofluorescence of anatomical structures, such as lignified cell walls, it was possible to determine the changes of important shoot and root structures, mainly vascular bungles and development of secondary thickening. The differences in vascular bundles organisation, parenchymatic pith development in the root centre and the reduction of phloem part of vascular bundles were well observable. Moreover with increasing silver(I) ions concentration the vitality of rhizodermal cells declined; rhizodermal cells early necrosed and were replaced by the cells of exodermis. Further we employed laser induced breakdown spectroscopy for determination of spatial distribution of silver(I) ions in tissues of the treated plants. The Ag is accumulated mainly in near-root part of the sample. Moreover basic biochemical indicators of environmental stress were investigated. The total content of proteins expressively decreased with increasing silver(I) ions dose and the time of the treatment. As we compare the results obtained by protein analysis-the total protein contents in shoot as well as root parts-we can assume on the transport of the proteins from the roots to shoots. This phenomenon can be related with the cascade of processes connecting with photosynthesis. The second biochemical parameter, which we investigated, was urease activity. If we compared the activity in treated plants with control, we found out that presence of silver(I) ions markedly enhanced the activity of urease at all applied doses of this toxic metal. Finally we studied the effect of silver(I) ions on activity of urease in in vitro conditions.