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Application of thermal analysis in physiological characterization of microorganisms
Kočiová, Silvia ; Obruča, Stanislav (referee) ; Sedláček, Petr (advisor)
This diploma thesis deals with the applicability of thermal analysis in the influence of stress factors on microorganisms. The main aim of the presented work was to design and implement a series of experiments to thest the usability of advanced methods of thermal analysis in the characterization of microorganisms. Two bacterial strains were used as model organisms: Cupriavidus necator H16 and its mutant strain Cupriavidus necator PHB-4, which differs in the ability to produce polyhydroxyalkanoates. The basic technique used thermogravimetric analysis (TGA), which was optimized and applied in the study of water transport, behavior and determination of intracellular water content with respect to the influence of the presence of intracellular PHB granules. The results of this method were subsequently supported by TEM photos.
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Experimental and computer modeling diffusion of low-molecular solutes in gel – based carriers
Masár, Lukáš ; Gregorová, Eva (referee) ; Sedláček, Petr (advisor)
This diploma thesis is focused on combination of experimental study and computer modelling of diffusion processes in gel phases. The aim of experimental part of the diploma thesis was to test and optimize the setting of the diffusion coefficient in gel medium by using the method of horizontal diffusion cells, commonly used for study of diffusion processes through membranes. Specific description of experiments was to determinate the impact of presence of reactive component in inert hydro-gel carrier on final value of diffusion coefficient of low-molecular model diffusion probe. The defined dependencies were subsequently combined with computer simulation of diffusion process in a properly designed model in order to determinate the experimentally unavailable system parameters. The stated combination of both approaches was proved to be an appropriate instrument for studying of hydro-gels with a wide potential especially in the field of preparation of hydro-gel carriers with controlled release of active substances.
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Adhesion Properties of Semi-IPN Hydrogels
Candráková, Simona ; Sedláček, Petr (referee) ; Kalina, Michal (advisor)
This Diploma thesis deals with optimization of the hydrogel preparation with various additions of substances affecting adhesion, studying the adhesion of prepared hydrogel systems and modifying their adhesion properties. Prepared hydrogels were agarose, alginate and gellan polymer systems with additions of acrylic acid, acrylamide, calcium chloride and Tween 20. The experimental part of the diploma thesis focuses first on optimizing the preparation of individual hydrogels, from which, according to certain criteria, suitable representatives were selected to study adhesion and its controlled modification. Agarose and gellan hydrogels were selected as suitable representatives, which were then used in rheological measurements. Based on these measurements, the effect of the adhesive force and the adhesive work of individual materials was evaluated. It was found that the best adhesion properties of the materials used are unadjusted hydrogels, in the case of hydrogels with the addition of another substance, a negative effect on adhesion was observed, when the adhesion force was reduced and also the adhesion work was reduced.
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Reactivity of modified humic gels
Lang, David ; Sedláček, Petr (referee) ; Klučáková, Martina (advisor)
This bachelor thesis deals with humic acid gels and their ability to bind metallic ions on their surface. In the thesis the adsorption of copper ions on humic gels was studied. The gels were prepared by dissolving the humic acid in sodium hydroxide or sodium tripolyphosphate and then by precipitating with hydrochloric acid or magnesium chloride. Adsorption was studied at different concentrations of the copper (II) chloride and measured on UV-VIS spectrophotometer. It was proved from measuring that gels made from sodium tripolyphosphate are adsorbing less copper ions than the ones prepared by sodium hydroxide. Also, the copper ions are bound with smaller force on gels prepared with polyphosphate. Gels precipitated with magnesium chloride adsorb much more than gels precipitated with acid, Thus the extracted amounts are bigger.
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Preparation of hydrosorbents from humic acids
Nováčková, Táňa ; Giláni, Vladimír (referee) ; Sedláček, Petr (advisor)
This diploma thesis is focused on development and characterization of synthetic hydrogel materials containing humic acids. Based on the literature review, procedure for the preparation of synthetic superabsorbent containing humic acids was designed and optimized in order to maintain required functionality of the resulting materials, such as swelling abilities and to the controlled the release of humic substances. Very important part of this work was also characterization of superabsorbents by wide range of routine physic-chemical methods (rheometry, moisture analyzers, FT-IR). Preparation of these materials is aimed to their use in agriculture and in the environment.
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Fixation media for fluorescence microscopy of liposomes
Kvasnicová, Klára ; Sedláček, Petr (referee) ; Mravec, Filip (advisor)
This bachelor thesis deals with the synthesis of fixation medias suitable for fluorescence microscopy of liposomes. The theoretical part contains a literature search focused primarily on the characterization, classification and use of chemical fixatives in chemical practice. Experimental section also deals with the selection of appropriate fixative for preparation of microscopic preparations based on liposomes.
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Determination of Paracetamol content in selected drugs using ATR-FTIR spectrometry
Waczulíková, Kristína ; Sedláček, Petr (referee) ; Enev, Vojtěch (advisor)
This bachelor thesis deals with determination of paracetamol content in selected drugs by ATR-FTIR spectrometry and aims to design and optimize determination of paracetamol in dosage forms by a direct measurement of the sample, called ‘dry way’. Tablets of three drugs containing paracetamol have been studied. Wavelength ranges were determined from the measured FTIR spectra as regions where the absorptions of fillers (microcrystal cellulose, starch and magnesium stearate) were minimal. Absorption bands of paracetamol were selected at the wavenumbers of 1 503 cm-1 and 1 224 cm-1 in order to construct a calibration curve. The contents of paracetamol in the drug tablets were calculated using calibration curves obtained by the method of simple regression analysis. The lowest deviation from the amount of 500 mg paracetamol per tablet as reported by the manufacturer was from the calibration curve for paracetamol with microcrystalline cellulose. The determined amounts of paracetamol per tablet in the selected drugs lied within range 493.5–505.5 mg. These results point to the conclusion that the ATR-FTIR spectrometry method can be used for the quantitative determination of paracetamol in drugs using direct measurement, as deviations from the reference value of 500 mg did not exceed 1.5 % for cellulose and 3.85 % for magnesium stearate and therefore are within acceptable limits for the exploratory study.
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Encapsulation of soil bacteria in hydrogel carriers
Orišková, Sofia ; Smilek, Jiří (referee) ; Sedláček, Petr (advisor)
The goal of this bachelor thesis was both to review existing literature regarding the topic of inoculation of soil bacteria and test a relevant encapsulation method and optimize it. The evaluation process involved the study of various encapsulation techniques that involve hydrogel carriers suitable for agronomic purposes. Encapsulation allows controlled release of soil bacteria, and protects and stabilizes it, while ensuring longer shelf life. For the practical testing, Cupriavidus necator H16 was chosen as a nitrogen fixing bacteria for the inoculation. Through an ionic gelation method, it was encapsulated into alginate carriers, forming matrix microcapsules. Sodium alginate reacts with the cross-linking agent calcium chloride to form the capsules. The impact on the quality of the product was tested through several variables. What was revealed was that molecular weight of alginate was proven to have a significant impact. Alginate with higher molecular weight was shown to be suitable for the given system. The most desirable environment was distilled water or a TRIS-HCl buffer. However, the TRIS-HCl was unsuitable in cases of retrieving a dry product by lyophilization. Eventually, the viability of encapsulated cells was examined, and it was proven that encapsulated bacteria endure the process of encapsulation in the above-mentioned environment and they were gradually released from the carrier.
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Dissociation behaviour of natural biocolloids
Karbanová, Kateřina ; Sedláček, Petr (referee) ; Klučáková, Martina (advisor)
This diploma thesis is focused on the study of dissociation behaviour of natural biocolloids, namely humic acids and fulvic acids. Humic and fulvic acids are natural, heterogeneous, high molecular weight substances which behave as weakly acidic polyelectrolytes and they have complex not exactly described structure. They are formed by biochemical transformations of organic residues (mainly plants). They are part of the soil, water, peat, sediments and coal. Solubility of humic acids is affected by pH value. The higher the pH value is the higher the solubility is. Fulvic acids are soluble in whole range of pH values. The aim of this diploma thesis is to determine the dissociation constant for the five kinds of humic acids and four kinds of fulvic acids, which have been isolated from various natural sources. These samples were purchased from IHSS. Dissociation constants were determined by the conductometric method and a combination of measurment pH and the content of acidic functional groups in Na2SO4. UV-VIS spectrophotometry method was used to characterize the quality of humic acids and fulvic acids.
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Complex structural characterization of hydrogels based on semi interpenetrating biopolymer networks.
Trudičová, Monika ; Krzyžánek, Vladislav (referee) ; Sedláček, Petr (advisor)
The content of this diploma thesis was testing the applicability of available structural analysis techniques on a appropriate model hydrogel system. The main aim was to evaluate the advantages and disadvantages of selected structural analysis techniques and the influence of the composition change of the hydrogel system on its internal structure. Semi-interpenetrated hydrogels based on agarose of different concentration were chosen as model system, this type of material was chosen for simple and repeatable preparation and also for its application potential. Electron microscopy (SEM, cryoSEM), mercury porosimetry and turbidimetry were chosen as structural analysis techniques. Experimental results could be used to improve knowledge about the influence of hydrogel composition on its structure and the comparison of chosen techniques will be used for the choice of appropriate structural analysis in the future, which will be applicable to other hydrogel systems as well.
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