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Utilization of spectroscopy in study on stress-resistance of bacteria on the sigle-cell level
Köbölová, Klaudia ; Venerová, Tereza (referee) ; Sedláček, Petr (advisor)
This diploma thesis deals with the possibilities of stress resistance analysis of the Cupriavidus necator H16 and PHB-4 bacterial cells by spectroscopic methods and by testing the suitability of acridine orange as a viable dye. Based on research in literature, suitable analytical methods have been proposed, namely flow cytometer and fluorescence microscope. The first part of the experimental work was focused on the fluorescence microscope, which confirmed the basic character of acridine orange. Three stress factors, 50% and 70% ethanol, and acidic pH (pH = 1) were selected for viability monitoring. The bacteria fluoresced with green color after exposure to ethanol and red spots were found next to the cells, indicating their loss of integrity. In an acidic environment, the bacteria fluoresced red because of a partial DNA breakdown. The results were verified by the combination of propidium iodide with SYTO9 and the acridine orange suitability proved to be useful in this method. Image records were processed using image analysis. In the second part, acridine orange was used to monitor fluorescence using a flow cytometer. The result of the measurement was fluorescence expressed as histograms for individual channels, where fluorescence was characterized by median and mean intensity. By comparing the methods used, the acridine orange appears to be a more suitable fluorescent dye for the microscope than for a flow cytometer in which it was more difficult to obtain cell viability information. In the last part of the experimental work interesting photophysical properties of acridine orange were investigated.
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Utilization of thermal analysis in the study on effects of microbial inhibitors
Bošeľová, Miriam ; Obruča, Stanislav (referee) ; Sedláček, Petr (advisor)
This diploma thesis deals with the use of thermal analysis in the study on effects of microbial inhibitors. The main aim of this work was to determine the utilization of the method, which is mainly used in different fields of science and research. Three bacterial strains: Cupriavidus necator H16, its mutant strain Cupriavidus necator PHB-4 and Halomonas halophila, were used as model microorganisms. The inhibitory effect of levulinic acid on growth and metabolic activity was monitored by microcalorimetry. It was found that bacteria were able to adapt to levulinic acid to a certain concentration - Cupriavidus necator to 5 g/l and Halomonas halophila to 2 g/l. The thermal analysis results were compared to a conventional method, which is commonly used to study the growth of microorganisms.
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Interactions of soil organic matter with pollutants studied by microcalorimetric techniques
Macuráková, Viktória ; Sedláček, Petr (referee) ; Smilek, Jiří (advisor)
This diploma thesis dealt with the study of interactions of soil organic matter, specifically humic acids with a pollutant, where the surfactant Septonex was used. Humic acids were isolated from two different soils in the work, namely black earth and cambium. The theoretical part describes the formation of humic acids as such, their possible interactions with substances and the characterization of surfactants. The experimental part is devoted to the characteristics of humic acids using elemental analysis, thermogravimetry and then the most important part of the thesis, namely the monitoring of interactions using isothermal titration calorimetry. The experiment showed that the sample of isolated black earth at the surfactant concentration of 0,075 moldm3 had the best interaction with the surfactant.
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Security of Trapdoor Permutations under Preimage Leakage
Sedláček, Petr ; Hubáček, Pavel (advisor) ; Göloglu, Faruk (referee)
This thesis explores preimage leakage-resilient trapdoor permutations (PLR-TDPs) and their applications in proofs of storage replication and incompressible encodings. The thesis consists of three chapters covering the trapdoor permutations, formal definition of PLR-TDPs, and analysis of security properties of PLR-TDPs. The first chapter provides an overview of trapdoor permutations (TDPs), their def- initions, and applications in proofs of storage replication. Our results are presented in the second and third chapters. The second chapter formally defines PLR-TDPs and demonstrates their use by constructing a simple incompressible encoding in the random oracle model. The third chapter focuses on the existence of PLR-TDPs. It demonstrates the strong preimage leakage-resilience of fully random TDPs in an idealized model. We are the first to provide a partial formal justification for the conjecture of the preimage leakage-resilience of practical TDPs, such as RSA or Rabin permutations.
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Material flow concept of a production line supply
Sedláček, Petr ; Dorušáková, Kamila (referee) ; Zeizinger, Lukáš (advisor)
The content of this thesis is a research analysis of individual concepts in the field of corporate logistics with an emphasis on intra-company transport. In the practical part, the current state of the production line loading is evaluated and new variants of line supply are made on the of the given parameters. The work also includes the creation of simulation models of all variants in the Plant Simulation program and conclusions are drawn based on the data obtained.
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Preparation and characterisation of coatings for controlled-release fertilizers
Jašek, Vojtěch ; Sedláček, Petr (referee) ; Figalla, Silvestr (advisor)
The literary research of this Master's thesis is dedicated to controlled-release fertilizers (CRF). There is written the description of particular representatives of this kind of fertilizer and it also contains principles of nutrition's release mechanisms. Theoretical part is mainly focused on coated fertilizers, materials used for their production, coating technological processes and on a mathematical description of the diffusion transport which is the key of the mass transfer through polymer coatings. The laboratory preparation of innovative coatings based on modified vegetable oils is the main part of the experimental part of the thesis. It consists of the precursors' synthesis which can be applied on the fertilizer's surface in a liquid phase and polymerized by the UV-radiation in combination with an appropriate photoinitiator. There is described the synthesis of additional modifiers of precursors' viscosity and coatings' diffusive properties based on bio-source reactants such as sorbitol or ethyl lactate. The synthesized products are characterized by various methods such as volumetry, FTIR method or viscosimetry. The last part of the thesis contains the description of diffusive characteristics of coatings prepared out of the synthesized precursors.
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Modeling diffusion in hydrogels
Vrána, Matouš ; Sedláček, Petr (referee) ; Pekař, Miloslav (advisor)
This bachelor thesis is focused on basic knowledge about hydrogels and their potential uses, Brownian motion in hydrogels and it’s connection with diffusion and the possible modeling in COMSOL Multiphysics with the help of Particle Tracing Module. The aim of this work is to propose adjustments to a model given from COMSOL Application Library that could lead to a functional simple model true to the viscoelastic properties of the environment. Those were controlled through a given script for calculation of MSD in Matlab. The original model was adjusted with the help of rigid obstacles blocking particle transport. Second, rectangular model was also created, where the particle movement had been observed through created channels.
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PEG-based semi-interpenetrating polymer network hydrogels
Kadlecová, Michaela ; Kalina, Michal (referee) ; Sedláček, Petr (advisor)
This bachelor's thesis deals with optimization of the preparation of hydrogels based on polymer networks of polyehtylene glycol with the incorporation of a semi-interpenetrating polymer networking and the following chemical-physical characterization of the prepared hydrogels. Polyehtylen glycol diacrylate was chosen from the range of polyethylene glycol modifications as a model material for the formation of hydrogels. Based on this, the preparation using UV photopolymerization was optimized. After optimization of the preparation, selections and following incorporation of the polyelectrolyte took place. Sodium polystyrene sulfonate was chosen as a model polyelectrolyte. Then, there was a basic characterization and comparison of the prepared hydrogels based on polyethylene glycol diacrylate with and without the addition of polyecletrolyte. Swelling, rheology, scanning electron microscopy were used for basic characterization and transport characteristics were investigated using diffusion.
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Tailoring transport properties of controlled release systems based on polyhydroxyalkanoates.
Apsalikova, Zarina ; Obruča, Stanislav (referee) ; Sedláček, Petr (advisor)
V rámci předložené práci, polyhydroxyalkanoáty s odlišnými monomerními jednotkami, jako 3-hydroxyvalerát, 4-hydroxyvalerát, 4-hydroxyhexanoát, a 5-hydroxyvalerát byly připravovány za využití bakteriálního kmenu Aneurinibacillus (AH30, AFN2) za účelem porovnání transportních vlastnosti nosičů na bázi izolovaných kopolymerů. Na základě výsledku plynové chromatografii (GC-FID) se ukázalo, izoláty jsou schopné produkovat PHA s různým procentuálním zastoupením monomerů. Dále molekulová hmotnost a index polydispezity izolovaných kopolymerů byly analyzovány pomoci SEC-MALS. Samotné nosičové systémy byly připravovány s využitím izolovaných kopolymerů a komerčního poly(3-hydroxyburyrát). Optimizace byla zaměřena na nastavení podmínek pro tvorbu částic, filmu a porézního systému. Zkoumanými podmínkami byly koncentrace roztoku, množství pomocné látky, a proces izolace nosičů. Vytvořené nosičové systémy byly charakterizovány z pohledu jejich schopnosti uvolňovat aktivní látku (ibuprofen) do modelového prostředí (fosfátový pufr). Na základě provedené charakterizaci bylo stanoveno, že transportní vlastnosti jsou ovlivněny strukturou polymeru a interakcemi v systému polymer-rozpouštědlo. Skenovací elektronová mikroskopie, diferenciální skenovací kalorimetrie, infračervená spektroskopie s Fourierovou transformaci a UV-VIS spektroskopie byly využity jako nástroje pro porovnání a pochopení korespondence mezi chemickou strukturou PHA a jejich transportními vlastnostmi.
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