The energy utilization of the alternative fuels is one of the main topics for future developments of recoverable sources in the European Union and in the Czech Republic. The aim of research is combustion tests in the fluidized-bed boiler Foster Wheeler located at Štětí. The experiments are carried out for Czech brown coal, wood, sewage sludge and wastes including analyses and recommendations for optimal thermal utilization and minimizing harmful emissions. The second step is thermal analyses of coal, alternative fuel- wood pellets and sewage sludge from treatment plant. From the results of experiments and thermal modeling it is clear that 15 % of alternative fuels can be used in the large fluidized-bed boilers located in the Czech Republic., Pavel Kolat, Bohumir Čech, Dagmar Juchelková, Helena Raclavská and Juraj Leško., and Obsahuje bibliografii
Review article presents utilisation of coal in industry, coal in power generation, gas production, Czech energy policy and outlook and application of clean coal technology in the Czech power stations. The further exploitation and utilisation of Czech coal resources requires the implementation of development programme aimed at the application of the new, economically effective technologies, of coal mining, utilisation, gasification. Emissions of GHG in CR., Václav Roubíček, Pavel Kolat and Jaroslav Buchtele., and Obsahuje bibliografii
Incorporation of labelled CO2, 3-phosphoglycerate (PGA), phosphoenolpyruvate (PEP) and pyruvate into hexane extractable rabber ffactions in the cut shoots of guayule {Parthenium argentatum Gray) was determined in order to evaluate the role of photosynthesis in providing precursors for rubber biosynthesis. DCMU inhibited the incorporation of labelled CO2 and PGA into rubber. The incorporation of i'*C02 into rubber depended on irradiance. Enzymatic activities of phosphoglyceromutase, enolase, pyruvate kinase and pyruvate dehydrogenase complex found in purified chloroplasts from the leaves indicated the chloroplast autonomy for intraplastid acetyl coenzyme A formation. The enzymes related to the biosynthesis of isopentenyl pyrophosphate (IPP) were associated with both leaf and stem extracts. Rubber producing enzyme activities, námely IPP isomerase and rubber transferase, were abundantly localized in roots and stems of guayule while the leaves exhibited low activities of these enzymes. Hence the leaves of guayule play a major role in providing precursors for rubber formation in stems and roots.
Vnitrodruhová variabilita v chování zvířat, tj. personalita, výrazně ovlivňuje ekologické i evoluční procesy. V tomto článku se pojednává o tom, jak může personalita vzniknout u pavouků a její vliv na potravní sítě., Inter-individual behavioural differences, i.e. personalities, play a very important role in eco-evolutionary processes. Here, we describe how spiders’ personalities arise and how they influence the dynamics of food webs., and Radek Michalko.
In the temperate haptophyceaen Pavlova luíheri (Droop) Green and Pavlova sp. (not yet estimated) the dominant pigments were chlorophyll (Chl) a (57 %), fucoxanthin (17 %) and diadinoxanthin (13 %); other estimated pigments were p-carotene, Chl c, cA-fucoxanthin and diatoxanthin. UV-A of 1.7 W m-2 had no effect on pigmentation of P. luíheri, but led to a reduction of the pigment contents of Pavlova sp. The damaging effect of a high UV-A dose (11.0 W m'^) was more pronounced than that of UV-B irradiance. The strongest reduction of pigment concentrations of both Pavlova species was observed after an exposure to UV-A (11.0 W m'^) plus UV-B (1.2 W m-2). Under this combined irradiation an increase of the diatoxanthin content and a decrease of the diadinoxanthin content was found.
The purpose of this study was to determine the production of metalloproteinases (MMP) 2 and 9 following UV-B irradiation in human corneal epithelial cells and fibroblasts. Epithelial cells and fibroblasts were separated from human donor corneas and exposed to UV-B lamp irradiation for 20, 40, 80 and 120 s. Media samples were collected at 8, 24, 48 and 72 h and gelatinase A and B production was assayed by the ELISA test. Statistical significance of production was assessed by the paired t-test. Increased production of MMP-2 was found in human corneal fibroblasts in response to UV-B irradiation. A statistically significant production of MMP-2 was not observed in human corneal epithelial cells following UV-B exposure. We did not detect any increase in MMP-9 after irradiation in either epithelial cells or fibroblasts. MMP-2 is produced by the corneal fibroblasts in the acute phase after UV-B irradiation. MMP-9 is not released in vitro following UV-B irradiation damage and therefore does not directly participate in the pathophysiology of acute photokeratitis., I. Kozák, D. Klisenbauer, T. Juhás., and Obsahuje bibliografii
The review deals with the comprehensive analysis of ultraviolet-B (UV-B) induced alterations in photosynthetic processes of higher plants and possible protection mechanisms. Between two photosystems, photosystem 2 (PS2) is main target for UV- B radiation stress. Depending on the mode of treatment, the oxidising side of PS2 and reaction centres are mainly affected by UV-B treatment. As response to UV-B stress plants develop some inherent adaptive mechanisms which decide the extent of the overall damage.