National Repository of Grey Literature 106 records found  1 - 10nextend  jump to record: Search took 0.01 seconds. 
Optimization of separation and quantification of prospective products of big bang
Smitka, Jaroslav ; Tesařová, Eva (advisor) ; Kalíková, Květa (referee)
The thesis is a contribution to research aimed at modeling the conditions of the Big Bang and monitoring possible reaction products. As the starting compounds were selected 2- amino-1-butanol, 3-methoxy-1-propanol, 2-methyl-1-butanol, formamide, some of which were subsequently bombarded by PALS at J. Heyrovsky Institute of Physics, Academy of Sciences. Gas chromatography hyphenated with mass spectrometry and liquid chromatography with UV detection were used for analysis. In GC-MS, calibration of 3- methoxy-1-propanol and 2-methyl-1-butanol was carried out and LOD and LOQ were calculated. Comparison of 3-methoxy-1-propanol and bombarded 3-methoxy-1-propanol did not show the emergence of new products since 3-methoxy-1-propanol was in excess. The found compounds can be more likely identified as impurities present in a solvent or in the individual standards. The optimized HPLC system has managed to separate the three standards. Formamide, which is unsuitable for analysis by gas chromatography, due to its high polarity, however, eluted in all tested systems with system peak (the dead time marker). Nevertheless, the bombarded sample was analyzed for comparison with the original standard. Comparison, however, showed no reaction products in the bombarded sample. Key words: big bang laser sparks formamide...
Separation of some tryptophan derivatives using cyclofructan based chiral stationary phase
Martínková, Monika ; Tesařová, Eva (advisor) ; Vozka, Jiří (referee)
Chiral stationary phase based on R-naphtylethyl derivatized cyclofructan was used for separation of tryptophan derivatives. In normal mode were tested different compositions of mobile phase and minorite modifiers. The aim of this work was to find suitable separation conditions.
Activity of hydrolytic enzymes in process of prodution of biogas
Kolouchová, Kristýna ; Tesařová, Eva (advisor) ; Kopečný, Jan (referee)
In this work, the activities of hydrolytic enzymes, functioning in the hydrolytic stage of the production of biogas, have been determined. The activities of -amylase, -xylanase, and -glucosidase have been measured in five samples collected from the following steps of biogas production:. cow dung from the adjacent cowshed, cow manure from the homogenization tank for dosing biogas plant, digester sludge from the outside biogas fermenter, degister sludge from the inside biogas fermenter, and sludge of digestate from digestate tank. Samples for measurement of enzyme activities were provided by agricultural biogas station AGRI FAIR in Deštná, which uses for biogas production cow manure and corn silage The activities of hydrolytic enzymes in the production of biogas are crucial, because degradability of feed material is the limiting factor. Activity of a amylase had highest value in cow dung and cow manure due to food containing high levels of starch. In subsequent phases falls evenly. In the indoor digester and digestate is already depleted substrate and the activity is at zero level. Its activity is almost three times higher than - glycosidase in cow dung and cow manure, but in the last three stages of -glycosidase activity exceeds   amylase and its value is nearly stable. -xylanase has...
Natural sources and sinks of volatile chlorinated hydrocarbons in the spruce forest ecosystem
Štangelová, Pavla ; Tesařová, Eva (advisor) ; Pavlík, Milan (referee)
Biogeochemical cycle of chlorine, particularly the formation of organically bound chlorine is still not well understood. In continental ecosystems chlorides act as source of chlorine, and also as a stress factor. Chlorides originate from precipitation of marine cloud masses. Organically bound chlorine in the environment is formed naturally by biotical and abiotical way. The biotical factors are microorganisms, plants, soil enzymes and animals. Volatile chlorinated hydrocarbons (VOCl) represent one group of organically bound chlorines. Several volatile chlorinated hydrocarbons reacts with atmospheric ozone, consequently causing depletion of the ozone layer. The most important known terrestrial source of volatile chlorinated hydrocarbons is the spruce forest ecosystem. Chlorine in the soil can be transformed by microorganisms into organically bound chlorine or translocated by transpiration stream in plants, where they are also transformed enzymatically into organically bound chlorine, and both of them can be emitted into the atmosphere. Too large amounts of chloride can affect the physiological functions of plants. In this thesis experiments were designed for measuring the natural emissions of volatile halogenated hydrocarbons from plants and fungi, with various periods of incubation, and also to...
Characterization of separation systems for determination of enantiomers
Geryk, Radim ; Tesařová, Eva (advisor) ; Ševčík, Juraj (referee) ; Nováková, Lucie (referee)
(EN) The dissertation thesis is focused on the research and characterization of retention and enantiorecognition mechanisms of chiral stationary phases based on derivatized polysaccharides. The separation systems with a variety of modern stationary phases (both achiral and chiral) were characterized in detail to provide a comprehensive view of the interactions participating in the separation process. The study of the retention/separation behavior significantly facilitates the development and the optimization of new enantioselective methods for a wide variety of compounds. The work deals with the comparison of enantioselective performance of polysaccharide-based chiral stationary phases. The objectives are to show the differences of separation behavior among these chiral stationary phases, as they differ by the nature of the polysaccharide backbone (amylose versus cellulose), by binding of chiral polymer to silica support (coated versus immobilized stationary phase) and by the phenyl moiety in the reversed and normal phase HPLC. In both separation modes amylose-based chiral stationary phases exhibited higher enantioselectivity, especially for acidic and bifunctional analytes. Chiral stationary phases based on derivatized cellulose showed higher enantiodiscrimination potential for basic analytes....
Study of bioactive secondary metabolites produced by fungi of genus Geosmithia using UPLC-DAD-TOF-MS
Musil, Karel ; Bosáková, Zuzana (advisor) ; Tesařová, Eva (referee)
(EN) This work is dealing with study of fungal strain RJ0258 (Geosmithia sp.9) which was previously found to be the producer of secondary metabolites with antimicrobial activity. Production of secondary metabolites is significantly dependent on the conditions of cultivation and the subsequent gaining of these metabolites depends on the extraction method as well. This thesis involves the optimization of the cultivation conditions for fungal culture to ensure maximum production of substances with antimicrobial activity, the subsequent treatment of the fermentation medium, the extraction procedure focused on biologically active substances and finally the chromatographic separation. The most suitable design of the fermentation broth was chosen based on the tests - Malt extract agar medium (MEA - 100 ml, malt extract - 2 g, glucose - 2 g, pepton 0,1 g, pH adjusted to 5-6). Moreover, it was found out, that the optimal time of cultivation is 11 days, because, according to the test of biological activity, there is the highest production of secondary metabolites with antimicrobial activity. Following cultivation, the fermentation medium was extracted liquid-liquid extraction employing solution of 5% acetic acid in ethyl acetate. After evaporation and dissolution of the extract the obtained extract was...
Study of peptide digestion kinetics by trypsin and chiral separations of biologically active compounds by HPLC
Šlechtová, Tereza ; Tesařová, Eva (advisor) ; Čabala, Radomír (referee) ; Mikšík, Ivan (referee)
This dissertation thesis composes of two parts; the first part focus on the characterization of trypsin, enzyme frequently used in proteomic research for the investigation and identification of protein sequences, and its peptide digestion kinetics. The second part is aimed to the enantioseparations of biologically active compounds. First part of this project focus on tryptic digestion of synthetic peptides and the development of HPLC method for the identification of synthetic peptides and their fragments. Using the in-solution digestion and HPLC method, relative kinetic constants were determined for problematic sequences. Amino acids responsible for the decrease in trypsin catalytic activity and their location towards the cleavage site were studied. Certain slight exopeptidase activity of trypsin was noted, especially at the end of peptide chain. Furthermore, three columns with immobilized trypsin used in HPLC were compared concerning their catalytic activity. The immobilization of enzymes on solid support is used to elevate the amount of enzyme present during digestion and to assure better repeatability and reproducibility of obtained results. Activity of a new trypsin column synthesized at the University of North Carolina at Chapel Hill was compared to two commercially available trypsin columns....

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1 TESAŘOVÁ, Eliška
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