Sborník abstraktů 2010 - Fakulta chemická - Vysoké učení technické ...

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Biotransformation of arsenic in marine organisms - degradation of arsenosugars in decomposing algae Jana Navrátilová Faculty of Chemistry, Brno University of Technology, Institute of Food Science and Biotechnology, 612 00 Brno, Czech Republic, xcnavratilovaj@fch.vutbr.cz The biotransformation of arsenic compounds in marine organisms have been discussed extensively because marine organisms can accumulate high arsenic concentrations. An important role in arsenic cycling in marine ecosystems play marine macroalgae. In general, arsenic in marine macroalgae is present as dimethylarsenoribosides, while in animals the most abundant arsenic species is arsenobetaine. Dimethylated arsenoribosides are considered likely precursors to arsenobetaine. Arsenosugars in marine algae can occur at concentration exceeding 50 mg As kg-1 dry mass. Arsenosugars are synthetised in alga from arsenate what is the main arsenic species in seawater. That process is considered be a detoxification mechanism. An important fact is the chemical similarity of arsenic and phosphorus, arsenate may follow the same metabolic pathways in organisms as phosphorus, and interfere in phosphorus metabolism. The transformation of organoarsenicals during the natural decomposition of brown kelp Ecklonia radiata was followed using HPLC/ICPMS. Ecklonia radiata contains most of its arsenic as dimethylarsenoribosides (glycerol, phosphate, sulfonate are dominant macroalgae species). The oxo-arsenosugars originally present in Ecklonia degraded first to dimethylarsinoylethanol (DMAE), and then to dimethylarsinate (DMA) and inorganic arsenic. The rate of degradation and the proportions of degradation products depended on the extent of contact of the alga with air. There was also a significant quantity of non-extractable or recalcitrant arsenic present. Key words: algae, arsenoribosides, degradation, HPLC-ICPMS
The Kinetics of Al-Si Spinel Phase Crystallization from Thermal Treated Kaolin Magdaléna Nosková Petr Ptáček, František Šoukal, Tomáš Opravil, Jaromír Havlica, Jiří Brandštetr Brno University of Technology, Faculty of Chemistry, Institute of Materials Chemistry Purkyňova 118, 612 00 Brno, Czech Republic xcnoskova@fch.vutbr.cz Crystallization of Al-Si spinel from medium ordered kaolin with high content of kaolinite was investigated using differential thermal analysis (DTA). The effective activation energy of process has been evaluated from dependence of an exothermic peak of crystallization on heating rate. Within applied interval of heating rate (1 – 40 Kmin -1 ) the temperature of peak maximum increases from initial value 1220.5 K to 54.2 K. The activation energy of this process (856 ± 2 kJmol -1 ) was calculated using the Kissinger equation. The growth morphology of Al-Si spinel crystal was evaluated from the Avrami parameter. The average value of morphology parameter determined within the observed interval of heating rate is 3.08 ± 0.03. This value indicates that mechanism of crystallization of the cubic phase proceeds by bulk nucleation of the new phase with constant number of nuclei and three-dimensional growth of crystals is handled by the reaction rate on the interface of phases. Keywords: Al-Si spinel, Kaolin, Kaolinite, Heterogeneous kinetics, Thermal Analysis 57
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STUDENTSKÁ ODBORNÁ KONFERENCE CHE
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Obsah - Contents Sekce středoškol
Page 5 and 6: Porovnanie rôznych predseparačný
Page 7 and 8: Sekce středoškolských studentů
Page 9 and 10: Vliv organické a anorganické form
Page 11 and 12: Studium vlastostí materiálů v ok
Page 13 and 14: Měření obsahu radonu v přírodn
Page 15 and 16: Stanovení biogenních aminů a pol
Page 17 and 18: Efekt snížené exprese APE u lids
Page 19 and 20: Vliv aplikace přípravku Supergest
Page 21 and 22: Stanovení obsahu mastných kyselin
Page 23 and 24: Izolace polyfenolických glykosidů
Page 25 and 26: Problematika stanovení léčiv v o
Page 27 and 28: Sekce studentů bakalářských a m
Page 29 and 30: Zmeny v obsahu organickej hmoty v p
Page 31 and 32: Vliv způsobu přípravy systémy b
Page 33 and 34: Biopolymerní hydrogely s obsahem h
Page 35 and 36: Interakce hyaluronan-tenzid za níz
Page 37 and 38: Production of Polyhydroxyalkanoates
Page 39 and 40: Zhodnocení odpadového hospodářs
Page 41 and 42: Sekce studentů doktorských studij
Page 43 and 44: The Influence of Different Hydrothe
Page 45 and 46: Analysis of casein content in cow m
Page 47 and 48: Image Analysis of Screen Printed Co
Page 49 and 50: Fluorescence Probe Study of Potenci
Page 51 and 52: Application of physico-chemical met
Page 53 and 54: Monosaccharide anhydrides in PM1 an
Page 55: Novel Biodegradable Macromonomers B
Page 59 and 60: Markers for organic, conventional w
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