National Repository of Grey Literature 131 records found  1 - 10nextend  jump to record: Search took 0.00 seconds. 
Characterization of bacterial strains obtained in evolutionary engineering
Chatrná, Vendula ; Sedláček, Petr (referee) ; Obruča, Stanislav (advisor)
This diploma thesis deals with application of evolutionary engineering on PHA producing bacterial strains. Two bacterial strains, Cupriavidus necator H16 and Halomonas halophila, were chosen for the evolutionary experiments. Copper cations (Cu2+) and sodium chloride (NaCl) were chosen as the selective pressure for C. necator H16; acetic acid (AA) and levulinic acid (LA) for Halomonas halophila. The adapted strains were during long-time evolutionary experiments characterized by GC-FID and SEC-MALS. The growth of the adapted strains was studied by the mean of optical density measurement. The amount of viable cells was determined by spectral FC after their expositon to selected stress factors. Specific enzyme activities of enzymes involved in citrate and glyoxalate cycle, enzymes generating NADPH, LA metabolism enzyme and PHA biosynthesis enzymes were determined. The adapted strains were compared with the wild-type of strains. The successfull adaptation of C. necator H16 adapted to Cu2+ was detected. Biomass and PHA production of both wild and adapted H. halophila strains cultivated in lignocellulosis waste were determined. It was found out that H. halophila adapted to the LA is capable of producing more PHA than the wild strain of this bacteria.
Modelling of particle thermal motion
Orság, Miroslav ; Sedláček, Petr (referee) ; Pekař, Miloslav (advisor)
The goal of this thesis was to get familiar with the basics of mathematical description of the thermal motion of particles in a given media, and with other possibilities of the software package COMSOL Multiphysics. A model for viscous and viscoelastic environments was created, a uniform and user friendly system for simulation and calculation of MSD and system for data conversion from FCS to MSD. Furthermore, the possibilities of the model for use in microrheology were assessed and another procedure in the implementation of the COMSOL program in the characterization of gels was proposed.
Influence of hydroxyacids on transdermal absorption of selected active pharmaceutical ingredients
Volhinava, Anastasiya ; Němcová, Andrea (referee) ; Sedláček, Petr (advisor)
Diploma thesis deals with the experimental study of transdermal transport of individual hydroxyacids and their combination with water-soluble vitamins. During this work the literature review was prepared, which was focused on the use of hydroxyacids in the cosmetic and pharmaceutical industries. At the same time the current state of use of water-soluble vitamins for topical applications was studied. Series of experiments was performed using Franz diffusion cells to simulate transdermal transport in vitro across cutaneous, synthetic and artificial Strat M ® membranes. The methodology of sample preparation and analysis of their transport properties was invented and optimized. The optimized methodology was subsequently used in a series of diffusion experiments in which the penetrated amount of hydroxyacids was analyzed by ion chromatography. The concentration of water-soluble vitamins was determined by HPLC. All examined active substances demonstrate positive penetration properties. The best results were obtained with combination of glycolic acid with pyridoxine.
The Suggestion of Optimal Supply Process for New Orders
Adamík, Vít ; Sedláček, Petr (referee) ; Jurová, Marie (advisor)
The topic of diploma thesis was implemented in selected mechanical engineering company producing precision parts in small series. The main aim of the thesis is to create the suggestion of optimal supply process for new orders. The first part of thesis describes the company, area of its business and the processes of the order. In second part, the production analysis is carried out: production order path, production analysis for two reference parts, comparison of all time delay over two last years, find bottlenecks in the supply process. Base on analysis, theoretical approaches was described. In the last chapter there are suggestions for improvement of supply processes and thus shortening of production time of new orders.
Study on adhesion properties of hydrogels to solid surfaces
Šindelářová, Anna ; Sedláček, Petr (referee) ; Smilek, Jiří (advisor)
This bachelors thesis deals with optimization and subsequent verification of the applicability of an unconventional method for determination of adhesion properties of hydrogels and materials related to them, which will then be useful for measuring the adhesion of hydrogels to solid surfaces using rheological techniques. In the case of the presented thesis, the determination of adhesion properties by means of rheometer and simple experiments such as slipping of measured materials on inclined surface is chosen. The results of both of these methods are compared to each other and also to the knowledge gained from literature. The applicability of the methods is assessed in terms of objective results, reproducibility, and whether the measured data are quantitative expressions of adhesion properties. It has been found that rheometry is useful as a reliable quantitative method of measuring adhesion. The rheometric data was reproducible and consistent. By this method, it was found that, with increasing concentration of dispersion, the adhesion force increases, which is in agreement with the knowledge obtained from literature.
Influence of particle size on microreology experiments using fluorescence correlation spectroscopy
Pavlíková, Stela ; Sedláček, Petr (referee) ; Mravec, Filip (advisor)
This diploma thesis deals with microrheology measured via the fluorescence correlation spectroscopy. As microrheological probes, fluorescently marked nanoparticles of 5 sizes in the range of 10-100 nm, were used. The particles had been immersed in a variety of concentrated glycerol solutions and agarose gels of different concentrations, and the FCS measurement revealed a diffusion coefficient of individual particles in each environment. Based on the coefficient, the viscosity of the glycerol needed to stop the particles could be determined. Particles of 10 nm size were not stopped even by the 100 wt% glycerol. In the case of the agarose gels, a combination of higher agarose concentration and larger particles resulted in an increase in the diffusion coefficient to an unlikely high value. This was caused probably by an agarose autofluorescence and the value indicates stopping of the particles in the given agarose gel. Later, the data acquired by the FCS measurement were converted to MSD curves using MATLAB software. The thesis discusses the influence of the experimental parameters on the shape of the MSD curve. The results showed that the number of particles and autocorrelation function have the most significant effect.
Biotechnological production of sophorolipids
Šimšová, Veronika ; Sedláček, Petr (referee) ; Obruča, Stanislav (advisor)
This diploma thesis deals with the microbial production of sophorolipids by the Starmerella genus yeasts. The theoretical part of the thesis includes general characteristics of biosurfactants with the focus on sophorolipids. There are described the options of biotechnological production of sophorolipids and fields of their possible applications. Furthermore, the theoretical part deals with the describtion of Starmerella bombicola yeast, which is often used for biotechnological production of sophorolipids. Six strains of the Starmerella genus were cultured in the basic medium suitable for sophorolipid produsction. The amount of produced sophorolipids was tested by the emulsification capacity assay, solubilization of crystalline anthracene assay, measuring the surface tension by the Du-Noüy-Ring method and determination of the sophorolipid concentration by extraction with ethyl acetate. The purity of the extracted sophorolipids was inspected by the Fourier Transform infrared spectrosopy (FT-IR) Based on the results, the Starmerella bombicola CBS 6009 and the Starmerella anomalae CBS 14178 strains were studied in greater detail. They were cultured in several production media of different composition and the effect of the individual components on the ability of the sophorolipid production was monitored. Based on the results, it was evaluated that the composition of the medium has a great influence on the production ability of the strains. The highest production rate of sophorolipids was achieved in the basic production medium and so was in the medium containing molasses and Indian waste oil. The cultivation mode has great effect on the sophotolipid production rate. It has been found that when cultured in a bioreactor, the strains produced sophorolipids in a larger amount and of a different quality than in the shaker flasks.
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.
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.
Insertion of polyelectrolyte additives in the hydrogel matrices - influence on the mechanical and transport properties
Dušenková, Alica ; Klučáková, Martina (referee) ; Sedláček, Petr (advisor)
The main aim of the diploma thesis is to investigate the influence of incorporated polyelecrolyte additives on the mechanical and transport properties of hydrogel. Hydrogels, based on polyvinylalcohol, were selected for these experiments. Gelation of polyvinylalcohol can be induced physically or chemically. The aim was to investigate the influence of sodium alginate, sodium polystyrene sulfonate and sodium polyglutamate. Mechanical properties were studied by rheology, through viscoelastic properties. Transport properties were analyzed by using two methods: diffusion pair and fluorescence correlation spectroscopy.

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