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Use of Hofmeister series of ions for fractionation of soil humic acids
Kebabová, Mona ; Doskočil, Leoš (referee) ; Enev, Vojtěch (advisor)
The bachelor thesis deals with the study of the structure and behaviour of humic acids (HA) in the presence of salts of the Hofmeister series of ions. Haplic Luvisol and sodium humate extracted from it were characterized by elemental analysis (EA) and thermogravimetric analysis (TGA) to determine the percentage of elements and ash. Fourier Transform Infrared Spectroscopy (FT-IR) was used to determine the functional groups in the sample. UV-VIS was used to investigate the effect of the Hofmeister salts. From its results were calculated the absorption coefficients EET/EBZ, E2/E3, E2/E4 and E2/E6, and the specific absorbance values SUVA254 and SUVA280. Other methods like Dynamic Light Scattering (DLS) and fluorescence spectroscopy were used to better understand HA's structure. The main goal of this bachelor thesis was to find a simple experimental method based on which we would be able to study supramolecular associations of HK, which are preferentially linked to the formation of weak intra- and intermolecular interactions in aqueous solutions.
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Characterization of new czech hop varieties
Faruzel, Vojtěch ; Diviš, Pavel (referee) ; Pořízka, Jaromír (advisor)
In this thesis the problem of characterization of new Czech hop varieties was investigated. The selected new varieties were Mimosa, Jazz and Blues. Their composition was compared with the widely used varieties Žatecký poloraný červeňák and Kazbek. The content of -bitter acids and -bitter acids, total phenolic content, flavonoid content and antioxidant activity were determined by UV-VIS spectroscopy for all hop varieties. The composition of hop essential oils was estimated by SPME-GC-MS. The diversity of the hop varieties was confirmed from the measured data by statistical analysis. The new varieties showed statistically significant differences in all monitored parameters, especially in comparison with the varieties Žatecký poloraný červeňák and Kazbek. The quantitatively different representation of -bitter acids and -bitter acids has an influence on the character and intensity of bitterness of these hop varieties. The composition of the hop essential oils, the content of phenolic substances, flavonoids and antioxidant activity are reflected in the different organoleptic properties of the hops analysed and of the beer.
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Solubility of lipophilic model carcinogens in water environment and effect of biomolecules
Řeboun, Martin ; Martínek, Václav (advisor) ; Hudeček, Jiří (referee)
2-Nitrobenzanthron (2-NBA) and 3-nitrobenzanthron (3-NBA) are pollutants widely occurring in the environment. The main sources of benzanthrones are combustion products (i.e. diesel exhausts, wood and cigarette smoke ...). 3-NBA is proven strong mutagen and carcinogen for bacteria and mammals and it is probably mutagenic also to humans, while 2- NBA shows genotoxic properties lower by 3-4 orders of magnitude. Here we consider the possibility that large difference in the solubility, and consequently also the difference in bioavailability of these isomers could be the factor partially explaining this phenomenon. One goal was to determine solubility of 2-NBA in water and compare it with 3-NBA and also with other carcinogens studied in our laboratory (Sudan I, ellipticin). Another objective was to evaluate the effect of model proteins (bovine serum albumin, lysozyme) on solubility of Sudan I and ellipticine. The last aim was to determine extinction coefficients of these compounds in water and in methanol. Two different methods were employed to determine the solubility of the model compounds. The first method was based on spectrophotometric verification of the Lambert- Beer law. The results were than compared with other method measuring concentration of a compound in saturated solution (In Czech) Key...
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Analytical methods for qualitative and quantitative determination of PHA in cyanobacteria
Černayová, Diana ; Samek, Ota (referee) ; Sedláček, Petr (advisor)
The diploma thesis is confused to verify the applicability of selected physicochemical and spectroscopic methods for characterization of cyanobacteria, with special emphasis on possibilities of qualitative and quantitative analysis of polyhydroxyalkanoates (specifically polyhydroxybutyrate (PHB)) accumulated in cyanobacterial cells. The sample basis of the work was formed by cultures of cyanobacterial strains of Synechocystis sp. PCC 6803 and Synechocystis salina CCALA 192. The cultures were were cultivated in several ways to cover the widest possible range of physiological conditions and PHB contents, in particular using an autotrophic way of cultivation on shakers and multicultural culture method in a basic culture medium,and in media enriched with 2% salt (NaCl ) as well as mixotrophic culture media with different types of the carbon substrate. After few weeks of cultivation, cyanobacterial cultures were obtained and complexly analyzed by following techniques- cell suspensions were analyzed by flow cytometry and UV-VIS spectrometry (transmission and diffusion transmission mode), dry cell biomass was characterised by gas chromatography to obtain a exact amount of PHB, and then FT-IR spectrometry and thermogravimetric analysis. The work aimed to assess whether any of these methods can be a quick and affordable alternative to the determination of PHB content to the most commonly used method of gas chromatography, but also to assess what additional information about the physiological state of cyanobacterial cells can provide test methods. The highest correlation on PHB content was determined for the parameters determined by infrared spectroscopy, in which specific peaks from the characteristic wavelengths for polyhydroxybutyrate were important. Weak correlations on PHB content were achieved in thermogravimetric analysis and cytometry, using the hydrophobic fluorescent probe BODIPY 439/503, which bound to lipophilic parts of cells. In addition to the determination of PHB, it was possible to determine pigments present in cyanobacteria (such as chlorophyll, phycocyanin and carotenoids) by flow cytometry and UV-VIS diffusion transmission spectrometry. In the end, results from all used techniques were compared by PCA analysis to determine the similarity of all analyzed samples.
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Generation of metallic nanoparticles by non-thermal plasma in liquids
Čechová, Ludmila ; Blahová, Lucie (referee) ; Kozáková, Zdenka (advisor)
This thesis focuses on the process of nanoparticle generation using new source of nonthermal plasma combining corona and pin-hole discharge in liquids. The theoretical part is focused on generation of metallic nanoparticles using various types of plasma discharge, the properties of metallic nanoparticles, their preparation by other methods and methods of characterization of nanoparticles. The experimental part deals with the preparation of copper, silver and gold nanoparticles from solutions of their precursors. The influence of experimental conditions, such as the influence of voltage polarity, effect of precursor concentration, effect of added electrolyte or reducing agent were investigated. All samples were analyzed by UV-VIS spectroscopy. Dynamic light scattering was used to determine the sice of nanoparticles. To confirm the presence of nanoparticles, samples were analyzed using scanning microscope with and energy dispersion spectrometer for elemental analysis.
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Study of the optical properties of titanium dioxide thin films
Rackovská, Anna Patrícia ; Schmiedová, Veronika (referee) ; Zmeškal, Oldřich (advisor)
The bachelor thesis is focused on the acquirement of thin film layers optical properties characterisation methods, done on inject printed titanium dioxide layers deposed on soda lime glass. Its main emphasis was on spectroscopic ellipsometry that was used to determine the refractive indices and the extinction coefficients of the samples in range of wavelengths from 200 nm to 850 nm and layer thickness. This thesis also shows another options of thin film layers preparation and several other methods to characterise properties of samples, specifically optical microscopy, used to set sample boundary as rough, mechanical profilometry which defined thickness of layers in range of 80 nm for the most thin sample to 250 nm for the most thick sample, and UV-VIS spectroscopy.
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Native hyaluronan as a delivery system for hydrophobic drugs
Černá, Eva ; Mravec, Filip (referee) ; Pekař, Miloslav (advisor)
The aim of this paper is to discover whether it is possible to use the native form of hyaluronic acid as a hydrophobic drug carrier for a targeted distribution in the body. In its structure, hyaluronic acid is a linear high molecular weight biopolysaccharide which is found in most living organisms. Hyaluronan is involved in many physiological processes and therefore is essential for the functionality of the human body. It is in most tissues of the human body, high concentration is in the skin, the vitreous body and is also observed in cancer cells that contain several receptors for hyaluronan. These receptors include CD44 and RHAMM. The interaction of the hyaluronic acid delivery system and the hydrophobic medicinal with these receptors could ensure a free passage for drugs to the affected tissue, where the release of the drug would destroy the affected cells. The drug would directly target the damaged tissue and did not burden the rest of the body like the cytotoxic agents do. In this paper the native form of hyaluronic acid, which we normally find in the human organism, was chosen as the carrier. Its properties do not stand above other carrier systems, but its biocompatibility and biodegradability in the body greatly exceed them. High molecular weight hyaluronic acid was used as a carrier and the hydrophobic dye sudan red G, a substance of similar properties, was used instead of a hydrophobic drug.
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Generation of nanoparticles by electrical discharge in liquids
Čechová, Ludmila ; Horák, Jakub (referee) ; Kozáková, Zdenka (advisor)
This thesis focuses on the process of nanoparticle generation by electric discharge in liquids. The theoretical part is focused on generation of electric discharge in liquids, various methods of preparation of nanoparticles, including plasmachemical methods and methods of nanoparticle characterization. The experimental part deals with the preparation of silver nanoparticles. As a precursor for generation of nanoparticles by electric discharge, an aqueous solution of silver nitrate was used. The influence of experimental conditions, such as the influence of voltage polarity, influence of delivered power, effect of concentration, effect of added electrolyte and time course of nanoparticle formation were studied. All samples were analyzed by UV-VIS spectrometry. To confirm the presence of nanoparticles in the solution, one of the samples was analyzed by a scanning electron microscope with an energy dispersion spectrometer for elemental analysis. Plasma diagnostics was performed using optical emission spectroscopy.
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Solubility of lipophilic model carcinogens in water environment and effect of biomolecules
Řeboun, Martin ; Martínek, Václav (advisor) ; Hudeček, Jiří (referee)
2-Nitrobenzanthron (2-NBA) and 3-nitrobenzanthron (3-NBA) are pollutants widely occurring in the environment. The main sources of benzanthrones are combustion products (i.e. diesel exhausts, wood and cigarette smoke ...). 3-NBA is proven strong mutagen and carcinogen for bacteria and mammals and it is probably mutagenic also to humans, while 2- NBA shows genotoxic properties lower by 3-4 orders of magnitude. Here we consider the possibility that large difference in the solubility, and consequently also the difference in bioavailability of these isomers could be the factor partially explaining this phenomenon. One of our goals was to determine the solubility of 2-NBA in water and compare it with 3-NBA and also with other carcinogens studied in our laboratory (Sudan I, ellipticin). The second aim was to determine extinction coefficients of these compounds in water and in methanol. Two different methods were employed to determine the solubility of the model compounds. The first method was based on spectrophotometric verification of the Lambert- Beer law. The results were than compared with other method utilizing determination of concentration of a compound in equilibrium with solid phase. (In Czech) Key words: solubility, UV-VIS spectroscopy, 3-nitrobenzanthrone, 2-nitrobenzanthrone, ellipticine, Sudan I
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Solubility of lipophilic model carcinogens in water environment and effect of biomolecules
Řeboun, Martin ; Martínek, Václav (advisor) ; Hudeček, Jiří (referee)
2-Nitrobenzanthron (2-NBA) and 3-nitrobenzanthron (3-NBA) are pollutants widely occurring in the environment. The main sources of benzanthrones are combustion products (i.e. diesel exhausts, wood and cigarette smoke ...). 3-NBA is proven strong mutagen and carcinogen for bacteria and mammals and it is probably mutagenic also to humans, while 2- NBA shows genotoxic properties lower by 3-4 orders of magnitude. Here we consider the possibility that large difference in the solubility, and consequently also the difference in bioavailability of these isomers could be the factor partially explaining this phenomenon. One goal was to determine solubility of 2-NBA in water and compare it with 3-NBA and also with other carcinogens studied in our laboratory (Sudan I, ellipticin). Another objective was to evaluate the effect of model proteins (bovine serum albumin, lysozyme) on solubility of Sudan I and ellipticine. The last aim was to determine extinction coefficients of these compounds in water and in methanol. Two different methods were employed to determine the solubility of the model compounds. The first method was based on spectrophotometric verification of the Lambert- Beer law. The results were than compared with other method measuring concentration of a compound in saturated solution (In Czech) Key...
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