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Speciation analysis of selenium compounds
Kramulová, Barbora ; Rychlovský, Petr (advisor) ; Šíma, Jan (referee)
Previously, selenium was known as an element with negative properties. However, in the last century, the significant positive effects on human health were detected. Currently, the function, behavior and toxicity of selenium are still not well known. The key to understand it is to do speciation analysis. The aim of this diploma thesis is to develop method for determination inorganic (sodium selenite and selenate) and organic (selenourea, selenocystine, selenomethionine) selenium compounds. Parameters of apparatus for electrochemical hydride generation with atomic absorption spectrometry detector were optimized, final conditions were set and optimal conditions for separation process using HPLC were investigated. Calibration dependences for selenium compounds were measured and analytical figures of merit were investigated. In conclusion, a coupled method HPLC- EcHG- QFAAS for determination of individual selenium compounds was proposed, and it was tested on urea samples. Calibrations for these measurements were investigated and analytic characteristics were calculated. Based on these comparisons it can be said that proposed method allows the determination of selected selenium compounds in both aqueous and urea matrices. Subject words: Spectroscopy, analytical chemistry Key words: Atomic absorption...
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Modification of Isoprenoids
Eignerová, Barbara
Abstract-AJ This PhD work is focused on the development of a new methodology aiming at the introduction of the perfluoroalkylated side-chains into various types of molecules. Synthesis of perfluoroalkylated compounds, owing to their biological properties, is a frequent target of organic chemistry.1 During the last couple of decades a number of different methods enabling the perfluoroalkylation have been developed. Among the classical methods belong procedures based on nucleophilic, electrophilic, or radical reactions.2 Interestingly, only a few examples of a transition metal catalyzed perfluoroalkylation reactions have been reported.3 Despite the fact that many of these methods have wide synthetic applicability, they are not general and search for new procedures is a desirable target. One of the possible and hitherto unexplored methods for the synthesis of perfluoroalkylated compounds is a ruthenium-complex catalyzed alkene cross-metathesis. Potentially, a reaction of a suitable terminal alkene reactant bearing a perfluoroalkylated moiety with the second terminal alkene could give rise to a new and more complex internal alkene. Regarding perfluoroalkylated alkenes suitable for the cross-metathesis reactions, (perfluoroalkyl)propenes can be considered as convenient substrates that can be easily prepared from...
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The role of sonication of PEO solutions with magnetic nanoparticles on morphology of the resulting nanofibrous mats
Peer, Petra ; Stěnička, M. ; Filip, Petr ; Pizúrová, Naděžda ; Babayan, V.
Properties of the resulting polymer nanofibres are often tailored by sonication technique applied prior or past an electrospinning process. The aim of this contribution is to evaluate morphology of nanofibrous mats formed by poly(ethylene oxide) with distributed magnetic nanoparticles (about 20nm in diameter) in dependence on time of sonication of the used polymer solutions. The solutions were exposed to sonication (intensity 200W, frequency 24 kHz) for 10, 30, and 60 minutes. It was shown that rheological characteristics (viscosity, storage and loss moduli) strongly depend on time of sonication (particularly phase angle) in contrast to electric conductivity and surface tension. For analysis of homogeneous distribution of magnetic field and magnetorheological efficiency (a relation of corresponding ciscosities) was process of electrospinning and resulting wuality of the obtained nanofibrous mats.
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The influence of acyclic nucleotide phosphonates PMEG and PMEDAP on p38 kinase signaling in human leukemic cells
Nejedlá, Michaela ; Entlicher, Gustav (advisor) ; Slaninová, Jiřina (referee)
PMEG [9-(2-phosphonomethoxyethyl)guanine] and PMEDAP [9-phosphonomethoxy- ethyl)-2,6-diaminopurine] are acyclic nucleoside phosphonates possessing cytotoxic properties. Antiproliferative effect of PMEG was demonstrated in various tumor cell lines in vitro. PMEG also represents an active component of some experimental prodrugs with enhanced selectivity and efficacy (such as GS-9219). PMEDAP seems to have weaker effect in vitro compared to PMEG, however it exhibited pronounced antitumor effect in SD-rats with spontaneous lymphoma. Therefore it was included in the present study as well. The aim of this study was to describe the interactions of PMEG and PMEDAP with p38 MAP kinase signaling and its relationship to the apoptosis. We investigated the influence of these compounds on the expression of four genes encoding p38 MAPK isoforms and whether this change is translated into the protein. It was found that PMEG up-regulates p38β and γ mRNA in CCRF-CEM cells and p38 β and δ in HL-60 cells. The effect of PMEDAP was less pronounced than that of PMEG. However, total p38 protein level remained unaffected by PMEG and PMEDAP. Activation of p38 MAPK cascade was also measured in the cells exposed to these agents using phospho-specific antibodies. We found that neither PMEG nor PMEDAP activated p38 kinase...
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Influence of bioeffectors application on phosphorus availability in substrate and on tomato yields
Beranová, Martina ; Kulhánek, Martin (advisor) ; Hanč, Aleš (referee)
In the past few years, the Czech Republic has been trying to increase the input of plant available phosphorus (P) due to the increasing its bioavailability in soil. From the point of view agriculture properties we can say that there is only little amount of readily available P in soil. Plants are unable to take up phosphorus sufficiently, which is mainly due to the fact it is part of various less soluble soil compounds. Therefore, there are new technologies aiming to make P more plant available. One of these technologies are so called Bioeffectors
The aim of this bachelor thesis was to increase the plant available phosphorus content in soil due to the bioeffectors application and therefore increasing tomato yield and quality.
The bioefectors used contained the following microorganisms: Trichoderma harzianum, strain T22, Bacillus amyloliquefaciens, strain FZB42 (RhizoVital), Pseudomonas sp. (pProradix) and a combination of Trichoderma harzianum with Bacillus subtilis with Zn and Mn added (CombiFector). The plant height, above ground biomass yields, tomato fruit yields and the contents of selected macro and micronutrients in soil (bioavailable form) and tomatoes fruit (total form) were estimated.
From the results is clear that: a) in the majority of monitored parameters, significant differences between treatments were not observed; b) Trichoderma treatment, in comparison to the Proradix showed significantly higher Mg content in soil, but only at the significance level 0.05; c) the total content of sulfur in the tomato fruit at the Trichoderma treatment was significantly lower in comparison with the Proradix and Combifector variations, and that at a significance level of 0.01.
In conclusion, it is possible to state that the application of bioeffectors, in the majority of cases, did not lead to significant changes of studied parameters. Therefore, it is necessary to look for new strategies that effectively increase the availability of phosphorus contained in soils and applied fertilizers. Therefore, it is possible to suggest further testing of bioeffectors in particular for further research in soils with varied characteristics and deeper microbiological analysis serving to understand the mechanisms of effectiveness and determine the viability of the products.
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Aroma active compounds of selected types of medical herbs
Pecinová, Ester ; Diviš, Pavel (referee) ; Vítová, Eva (advisor)
This thesis deals with aroma active compounds of selected types of medicinal herbs, specifically lavender (Lavandula officinalis), peppermint (Mentha piperita), sage (Salvia officinalis), St. John’s wort (Hypericum perforatum) and hyssop (Hyssopus officinalis). In the theoretical part the single herbs were characterized including botanical description, chemical composition, medicinal properties, adverse effects and the practical use; aroma active compounds present in herbs are also emphasized. Based on the literature search, gas chromatography coupled with mass spectrometry as currently the most frequently used method, was chosen for the assessment of aroma compounds. Solid Phase Microextraction was used for isolation of volatile compounds from dried herbs. Within experimental part of the work selected parameters of the SPME-GC-MS method were optimized, aroma compounds in samples of herbs were identified, and twenty four suspected fragrance allergens due to the Regulation (EC) N° 1223/2009 were also identified and quantified. Overall 69 compounds were indetified together with 2 allergens in lavender, 59 compounds including 5 allergens in peppermint, sage contained 49 compounds with 4 allergens included, 41 compounds were identified in St. John’s wort including 4 allergens and finally 64 compounds with 4 allergens included in hyssop.
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Compounds of terpenic nature in mint plants and the influence of elicitation on them
Jančová, Nikola ; Čáslavský, Josef (referee) ; Vávrová, Milada (advisor)
Diploma thesis is focused on study of compounds of terpenic nature in mint plants. Terpenic compounds are volatile hydrocarbons formed by several isoprenoid units with low molecular weight which cause the typical smell of plants. Presence of these compounds cause that plants seem to be fungicidal, bactericidal and insecticidal. Due to these properties, they can be used as botanical pesticides which are not toxic and no resistant organisms occur. Each plant contains relatively low concentrations of these compounds and therefore elicitors must be used for the increasing of terpenes amount. Elicitors activate defensive mechanisms in the plant leading to higher defense abilities and production of secondary metabolites. The identification and quantification of analytes was determined by gas chromatography in connection with mass spectrometry.
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Helium Cryostat for Experimental Study of Natural Turbulent Convection
Urban, Pavel ; Jícha, Miroslav (referee) ; Rotter, Miloš (referee) ; Fedor,, Ján (referee) ; Musilová, Věra (advisor)
V disertační práci je popsán heliový kryostat s experimentální válcovou konvekční celou pro studium proudění při přirozené konvekci za velmi vysokých Rayleigho čísel Ra (až do řádu 10^15) a Nusseltových čísel Nu (až do řádu 10^4). Pracovní látkou je studené 4He, které umožňuje díky výhodným fyzikálním vlastnostem dosažení velmi vysokých hodnot čísel Ra. Návrh kryostatu je založen na koncepci lázňových NMR kryostatů s nízkým odparem kryokapalin. Ve středu kryostatu je umístěna konvekční cela o průměru 300 mm a výšce 300 mm. Celu tvoří horní a spodní dno a výměnná střední část. Tyto díly jsou spojeny rozebíratelnými přírubami těsněnými indiovým drátem. Výměnná část umožňuje snadnou modifikaci geometrie cely. Hlavní přednost kryostatu spočívá v minimálním vlivu konstrukce cely a použitých materiálů na studovanou konvekci. Cela kryostatu je navržena pro pracovní tlaky do 250 kPa.
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