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Influence of stirring time on cosmetic stability
Grujić, Ksenija ; Sovová, Šárka (referee) ; Hurčíková, Andrea (advisor)
This bachelor thesis is based on the study of the influence of mixing time and revolutions per minute on the preparation of BB creams. The literature review of the thesis is based on the acquired information about the topic. The basic concepts and problems concerning dispersion systems, emulsions, mixing methods and cosmetics are described in this part of the thesis. The first segment of the experimental part is based on the preparation of BB creams themselves. The influence of agitation time and speed on the stability of prepared samples was tested. The stability of the samples was tested on LUMiSizer. The data were compared and processed.
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Study on the Effect of Biochar Application on Organic Matter in Soil
Kurková, Marie ; Sovová, Šárka (referee) ; Kalina, Michal (advisor)
This bachelor thesis studies the effect of the application of biochar on the composition of organic matter of two different soil samples. Specifically, the total content of organic matter in the soil and the ratio of humic and fulvic acids in these soils before and after the application of biochar were monitored. The composition of the soil mass was also observed thermogravimetrically and by using the certified method of humic and fulvic acids isolation from samples of studied soils. Furthermore, the effect of biochar on the growth of a model plant (maize – Zea mays) was observed. From this point of view, differences in plant growth were possible to observe from the beginning of the experiment, both in comparison with samples with and without biochar and in comparison with samples containing different doses of biochar. The type of soil used for cultivation experiments also influenced on plant growth.
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Biochar Effect on the Microbial Processes in Soil
Losová, Anežka ; Sovová, Šárka (referee) ; Kalina, Michal (advisor)
This bachelor thesis is focused on the investigation of the biochar effect on the microbial processes in soil. The theoretical part describes the properties of the soil, the characteristics of biochar, the definition of the methods of its production and the influence of biochar on microbial activity in soil. The experimental part was focused on optimization of the conditions for assessing of the effect of biochar on the rate of mineralization of soil organic matter through monitoring of the release of carbon dioxide from soil without biochar and from the biochar-amended soil with NPK fertilizer. Carbon dioxide was sorbed into sodium hydroxide during the incubation and the released amount was determined by titration. In the following part of the thesis, the experiments were focused on assessing the effect of increased soil temperature and humidity on the amount of CO2 released by soil respiration. Experimental data showed that biochar promoted the microbial activity and this effect was even enhanced by addition of NPK fertilizer to a defined amount of biochar. The increased temperature negatively influenced the microbial processes in soil, as the rate of soil respiration of carbon dioxide decreased. Excessive moisture had also a negative effect on microbial activity, resulted in the slowed rate of the soil respiration. In summary, biochar has a positive effect on microbial activity and the rate of mineralization of soil organic matter in a defined amount under the appropriate conditions and it can be used as a suitable soil conditioner in agriculture.
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Physicochemical and structural analysis for characterization of native and modified humic acids
Solanský, Pavel ; Sovová, Šárka (referee) ; Enev, Vojtěch (advisor)
This bachelor thesis is focused on structural and physicochemical characterization of native and methylated humic acid. These samples of humic acids, which were isolated from oxidized brown coal Leonardite, were characterized by thermal and spectrometric methods. The following analytical techniques were selected to determine the structural and physico-chemical changes between native and methylated humic acid: thermogravimetry (TGA), elemental analysis (EA), molecular absorption spectroscopy (UV/Vis), Fourier transform infrared spectroscopy (FTIR), fluorescence spectroscopy and last but not least nuclear magnetic resonance (13C NMR). The aim of this bachelor thesis was to find the differences in the structure of selected humic acids and also to verify the suitability of the techniques, which were used to characterize these biocolloid substances.
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Determination of content of selected nonsteroidal antiphlogistic – Ibuprofen in drugs using UV/Vis and FTIR spectrometry
Lindovský, Jiří ; Sovová, Šárka (referee) ; Enev, Vojtěch (advisor)
The main aim of bachelor thesis was to validate the content of the nonsteroidal antiphlodstic in drugs using spectrometric methods and subsequent comparison of results. Specifically, the thesis is focused on Ibuprofen, which is used mainly as analgesic and antipyretic. This substance was chosen for its significant ability of absorbing electromagnetic radiation in ultraviolet and infrared regions of spectra. For this purpose, various generics were selected and analyzed by molecular absorption spectrometry (UV/Vis) and infrared spectrometry with Fourier transform (FTIR). Very important factor influencing chemometric properties of the obtained results was optimalization of the spectrometric methods. After designing the working procedure, sample solutions were prepared from Ibuprofen-containing dosage forms using suitable solvent and these samples were analyzed spectrometrically. The content of Ibuprofen in individual samples was calculated from the measured UV/Vis and FTIR spectra using method of standard addition. The results show that infrared spectrometry seems to be more suitable method for determining the Ibuprofen content. Nevertheless, it should be noted that the choice of a suitable extractant is very important step in the determination. The information obtained from this bachlor’s thesis could be used in future routine inspections and monitoring of drugs.
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The influence of Biochar Cultivation in Soil on its Physicochemical Characteristics
Hladký, David ; Sovová, Šárka (referee) ; Kalina, Michal (advisor)
This bachelor thesis is focused on the effect of soil factors on the physical-chemical characteristics of biochar. It describes the change in biochar after a long-term cultivation experiment, as well as, sequential leaching that was implemented on a shorter time scale. The theoretical part describes individual physical-chemical characteristics, structure, possible applications and optimal methods of biochar characterization. In the thesis, we have learnt why biochar is called a soil conditioner, not a fertilizer. The experimental part deals with the study of changes in the physicochemical characteristics of biochar after the cultivation experiment. These results are compared with the sequential leaching of biochar in selected media (water, citric acid, hydrogen peroxide) that simulate the effects that can act on biochar in soil. The experimental results show the similarity of individual observed values of the samples after the long-term cultivation experiment and sequential extractions. It can be seen that the alkaline nature of biochar is caused by salts of alkali metal and alkaline earth metal. Mostly due to the presence of potassium in the biochar structure and then also the presence of calcium and sodium. These ions are also the explanation of the high conductivity, which together with pH, decreases significantly after five leaching cycles, and stabilize after a two-year cultivation period. All biochars samples used in the work have a high content of organic matter, which is a optimal prerequisite for the use in agriculture and the improvement of soil properties.
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Hydrogel fantoms in ultrasonic diagnostic
Chovancová, Aneta ; Sovová, Šárka (referee) ; Hurčíková, Andrea (advisor)
This Bachelor thesis is interested in hydrogel phantoms made from gelatin, agar and agarosa. The effect of food foil on the essential properties of gel matrixes such as drying and moulding has been investigated. These properties were investigated visually and gravimetrically. The speed of prepared gel matrixes was measured using high resolution ultrasonic spectroscopy depending on concentration. In the work, I follow up on the already performed Bachelor thesis [1], where gel matrices were measured in the environment of air and water. My gel matrices are dispensed to the machine's cell in a liquid state. Depending on the material used and the method of use of the food foil, gel matrixes prepared for visual and gravimetric evaluation from agar with a concentration of 3 % and 5 % without foil and with foil on the bottom were found to have a longer shelf life than other samples with the same use of foil. Gel matrixes of all three substances and all concentrations covered with food foil are able to last up to 20 days without massive drying and mould formation. The result of measuring the relative ultrasonic velocity of the hydrogels produced was found to increase the rate of spread of ultrasound for all measured substances as the concentration increased.
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Bioactive substances for face cream: Determination of stability of face cream incorporated with goat's milk
Dostálová, Tereza ; Sovová, Šárka (referee) ; Enev, Vojtěch (advisor)
The aim of this bachelor thesis is a stability trial of a skin cream incorporated with goat milk lyophilizates prepared in usual laboratory conditions. Firstly, the goat milk was denatured, to be further analysed via FTIR, elemental analysis and thermogravimetry. To compare the denaturation effect, measurements with native goat milk sample were performed as well. Next, an emulsion was prepared. First stability tests were performed using analytical centrifuge and the cream preparation procedure and component ratio was optimized. Stability trials were carried out at specified time intervals. Rheological properties – especially yield stress values and structure strength, determined by linear viscoelastic region and complex modulus – thermal endurance measured via differential scanning calorimetry and visual validation via optical microscopy and sample observation were tested and performed. Skin cream stability of sample stored at laboratory temperature was demonstrated, showing moderate sings of structure destabilisation. Product suitability for dry skin was proved by sensory analysis. The skin feeling was pleasant, and the cream moisturized the surface area, that it was applied to, according to evaluators. Visually, the emulsion appeared to maintain its properties during the experiment time range, it did not undergo a complete degradation of separation into two original phases, nor it was degraded, for example by mold.
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Study of bulk and hydration water in hydrogel systems suitable for medical applications
Řihák, Marek ; Sovová, Šárka (referee) ; Enev, Vojtěch (advisor)
This bachelor thesis focuses on a preparation of hydrogel systems based on hyaluronan and Septonex and on a design and optimalization of quantitative analysis of hyaluronan and Septonex in a supernatant after gelation. This work compares hydrogels formed from hyaluronan of two different molecular weights. The calibration curves of hyaluronan and Septonex were used to evaluate the experimental data. The thermogravimetric analysis and Fourier-transform infrared spectroscopy were used for the characterization of properties of the samples. The utilisation of the mentioned techniques to study molecular water subpopulations was discussed according to the obtained results.
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Biochar Effect on the Microbial Processes in Soil
Losová, Anežka ; Sovová, Šárka (referee) ; Kalina, Michal (advisor)
This bachelor thesis is focused on the investigation of the biochar effect on the microbial processes in soil. The theoretical part describes the properties of the soil, the characteristics of biochar, the definition of the methods of its production and the influence of biochar on microbial activity in soil. The experimental part was focused on optimization of the conditions for assessing of the effect of biochar on the rate of mineralization of soil organic matter through monitoring of the release of carbon dioxide from soil without biochar and from the biochar-amended soil with NPK fertilizer. Carbon dioxide was sorbed into sodium hydroxide during the incubation and the released amount was determined by titration. In the following part of the thesis, the experiments were focused on assessing the effect of increased soil temperature and humidity on the amount of CO2 released by soil respiration. Experimental data showed that biochar promoted the microbial activity and this effect was even enhanced by addition of NPK fertilizer to a defined amount of biochar. The increased temperature negatively influenced the microbial processes in soil, as the rate of soil respiration of carbon dioxide decreased. Excessive moisture had also a negative effect on microbial activity, resulted in the slowed rate of the soil respiration. In summary, biochar has a positive effect on microbial activity and the rate of mineralization of soil organic matter in a defined amount under the appropriate conditions and it can be used as a suitable soil conditioner in agriculture.
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