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Influence of surface termination of boron-doped diamond electrode on the electrochemical behaviour of phenol and its derivatives
Nedvěd, Michal ; Schwarzová, Karolina (advisor) ; Gabriel, Jiří (referee)
This thesis is devoted to the study of electrochemical oxidation of meta-substituted phenolic substances on a boron-doped diamond electrode. In the first phase, it was studied the effect of pH on their electrochemical oxidation by the methods of classical "direct current" voltammetry (DCV) and differential pulse voltammetry (DPV). The study was performed on three types of boron doped diamond (BDD) surfaces: polished, anodic and cathodically activated. In the second phase, attention was paid to the Hammett correlation to study the effect of the substituent on the potential of electrochemical oxidation of selected phenolic compounds. Among the substituents studied were (-H, -CH3, -OCH3, -(CH2)2COOH, -COOH a -NO2). In general, the oxidation potentials were lower in the basic medium than in the acidic medium on all studied surfaces. An exception was the studied phenolic acids, which could not be detected in an alkaline medium on the O-terminated BDD, probably due to electrostatic repulsion between the partially negative electrode surface and the acid dianion. The highest correlation coefficient for the dependence composed of all studied phenols was obtained for the polished and H-terminated surface at pH 11, ie the dissociated form of phenolic substances. The high electron density leads to easy...
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Modern fungicides and mechanism of their action
Zaleš, František ; Gabriel, Jiří (advisor) ; Ptáček, Petr (referee)
Fungicides are compounds, which are able to kill a fungi (they are therefore fungicidal), or they are able to slow or stop growth of a fungi (they are therefore fungistatic). Some fungicides also have insecticidal properties and can offer dual protection. This bachelor thesis is mainly dealing with fungicides, which are used to protect wood and wooden constructions from wood decaying fungi. Part of this bachelor thesis is a brief overview of wood decaying fungi and also an insight into the history of fungicides, but the main goal of this thesis is to offer a survey of currently used fungicides for wood protection against wood decaying fungi and also describe the mechanism of their action. Keywords: fungi, fungicides, buildings, general threat, wood decay, mode of action
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RNA elements in the genus Armillaria
Dvořák, Jiří ; Gabriel, Jiří (advisor) ; Tomšovský, Michal (referee)
Mycoviruses are widespread among the fungi. Most mycoviruses reported have dsRNA genomes. The first mycovirus was found in the edible mushroom Agaricus bisporus. Mycoviruses do not have an extracellular phase of their life cycle and are transmitted only by intracellular routes. Many mycoviruses reveal no apparent effect on their hosts. The genus Armillaria represents economically important edible fungal pathogens causing root rot in conifers and broadleaves trees. From this viewpoint, genus Armillaria presents an important subject of research studies. In this study we tried to find evidence for the presence of RNA elements in the respective genus. Total amount of collected strains was 52. CF-11 method for nuclei acids extraction was applied to 40 strains. The method is based on the affinity of cellulose powder for nuclei acids and specifically, the adsorption of dsRNA at ethanol concentrations of 15%. According to our results, there is no evidence for dsRNA elements occurence in the tested strains. The study was also focused on basic characterization of physiology of isolates, esp. to optimum growth conditions on agar plates and milled straw as well as on rhizomorph formation and fructification. No effect of pH changes and addition of various alcohols on rhizomorph formation was found, while primordia...
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Analysis of the composition and degradation of pharmaceutical substances and pharmaceutical preparations from the 18th and 20th centuries
Kudláček, Karel ; Nesměrák, Karel (advisor) ; Bosáková, Zuzana (referee) ; Gabriel, Jiří (referee)
The dissertation focused on the analysis of twenty historical remains of pharmaceutical substances and pharmaceutical preparations dating to the 18th and 20th century by liquid and gas chromatography with UV-spectrometric or mass spectrometric detection. The analytical approach was chosen with regards to the age and pharmaceutical forms of the analyzed historical remain. The authenticity of the sample was verified by identifying the active ingredients, their possible degradation products and other excipients by tandem mass spectrometry. The fragmentation of some analytes was also studied by tandem mass spectrometry. The stability of historical pharmaceutical preparations from the 20th century was assessed on the basis of a decrease in the concentration of active substances compared to the content declared by the manufacturer or, in case of historical pharmaceutical remains from the 18th century, on the basis of active substance concentrations determined in the historical residue and current reference material. A multi-analytical approach combining five analytical methods, the results of which complement each other, was used to analyze the historical remains of ointments. While the active substances identified in ipecacuanha were found to be partially degraded, they were completely degraded in senna...
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