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Exctretion of urinary N7 guanine and N3 adenine DNA adducts in mice after inhalation of styrene
Mikeš, Petr ; Mráz, Jaroslav (referee)
Adenine adducts of styrene : 3-(2-hydroxy-1-phenylethyl)adenine (N3αA) and 3-(2-hydroxy-2- phenylethyl) adenine (N3βA), were found in the urine of mice exposed to styrene vapor. Vast majority of styrene is metabolized to styrene -7,8-oxide. This reactive molecule is futher bio transferred either to mandelic and phenylglyoxalic acid or bounds to nucleophilic sites in biomolecules. Adducts of styrene oxide with amino acids contained in proteins and with purine and pyrimidine bases of nucleic acid were observed during in vitro tests. These styrene-7,8-oxide derived adenine adducts, as well as previously identified guanine adducts, 7-(2-hydroxy- 1- phenylethyl)guanine (N7αG) and 7-(2-hydroxy-2-phenylethyl)guanine (N7βG) were quantified by HPLC-ESI-MS2 and the excretion profile during and after repeated exposure to 600 mg.m-3 or 1200 mg m-3 of styrene for 10 consecutive days (6 h/day) was determined. The excretion was dose dependent. Total excreted amount of N3 adenine adducts (N3αA+N3βA) represents 0.8 ×10−5 % of the absorbed dose, while overall sum of N7 guanine adducts (N7αG+N7βG) yields about 1.4 ×10−5 % of the dose. No accumulation of the adducts was observed. Due to rapid depurination of the DNA, the excretion of both N3 adenine and N7 guanine adducts ceased shortly after finishing the exposure. Both N3...
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The Speciation Analysis of the Toxicological Important Forms of the Arsenic in Urban Particulate Matter Samples with the Detection QF-AAS
Jelínek, Petr ; Rychlovský, Petr (advisor) ; Červený, Václav (referee)
The topic of this diploma thesis was the speciation analysis of the toxicological important forms of the arsenic in urban particulate matter samples. The detection technique used in this work was atomic absorption spectrometry with quartz atomizer. Acetic acid, ammonium acetate, hydroxylamine, potassium hydroxide and sodium carbonate are recommended leaching agents for extraction of metals from urban particulate matter samples. Results of the presenting work are following: Acidic extraction reagents can be not recommended for the speciation analysis of the arsenic, because these reagents lower sensitivity of the determination of As3+ and As5+ too and destroy the quartz atomizer. Alkaline extraction reagents don't lower sensitivity of the determination of As3+ and these reagents don't destroy the atomizer, but lower sensitivity of the determination of As5+ was obtained. Recommended reagents aren't useful for extraction of the metals from urban particulate matter samples for the speciation analysis.
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Porphyrazine film for use in electrochemical sensor
Merhoutová, Jana ; Nesměrák, Karel (advisor) ; Ludvík, Jiří (referee)
Porphyrazine film for use in electrochemical sensor Abstract: A water soluble N,N',N'',N'''-tetramethyltetra-3,4-pyridinoporphyrazine complex containing cobalt cation (II) as a central atom was used like a mediator for preparation of electrochemical sensor. Such effects on a sensor function like an electrode carrier material, the manner of porphyrazine deposition, pH and thickness of the layer, were studied by cyclic voltammetry method. The sensor was tested for hydrogen detection in water buffer solution consequently.
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Measurement of spray characteristics using optical measurement methods
Ďurdina, Lukáš ; Otáhal, Jan (referee) ; Jedelský, Jan (advisor)
Diplomová práce se zabývá měřením charakteristik sprejů dvou tlakových vířivých trysek pro spalovací komoru malého turbínového motoru na zkušebním stavu za studena pomocí metod Particle Image Velocimetry (PIV) a fázové Dopplerovské anemometrie (PDA). Cílem měření bylo stanovit a porovnat charakteristiky sprejů obou trysek. Výsledky měření mají objasnit rozdílnost chování trysek za provozu a možný dopad na proces spalování. Úvodní teoretická část pojednává o základních fyzikálních principech atomizace kapalin, konstrukci a oblasti uplatnění tlakových vířivých trysek a o principech laserových diagnostických metod použitých při experimentálním měření. Nasledující část popisuje návrh a montáž zkušební trati a dalších zařízení navržených pro experimentální měření v této práci. Experimentální část se zabývá nastavením parametrů měřícího systému a zpracováním dat. Výsledky měření zahrnují vektorová rychlostní pole, axiální rychlostní profily a distribuce velikosti kapek pro různé provozní podmínky obou trysek.
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Determination of kadmium content in plant tissue of Norway Spruce and European Beech after application of cadmium oxide nanoparticles
Svozilová, Eva ; Mikuška,, Pavel (referee) ; Večeřa, Zbyněk (advisor)
The aim of this thesis is to monitor cadmium content in needles of Norway spruce and European beech leaves after controlled exposure to cadmium oxide nanoparticles and evaluate the potential risks of such nanoparticles to plants. Needles and leaves were harvested after a one-week and two-week exposure and prior to analysis of cadmium content, they were modified using relevant procedures. Samples were mineralized in nitric acid using pressurized microwave mineralizer and subsequently analyzed by atomic absorption spectrometry (AAS) with electrothermal atomization of cadmium content. Based on the results AAS analysis the transport of nanoparticles into the plant tissue of studied species was evaluated, comparing the content of cadmium in one week and two weeks experiment in the washed and unwashed samples of needles and leaves.
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