Národní úložiště šedé literatury Nalezeno 13 záznamů.  1 - 10další  přejít na záznam: Hledání trvalo 0.00 vteřin. 
Effect of pH on the Oxide Film Formation on a Pristine Zr Electrode
Hromadová, Magdaléna ; Kocábová, Jana ; Kolivoška, Viliam ; Pospíšil, Lubomír
Effect of pH on the oxidation of zirconium metal was studied by cyclic voltammetry in\naqueous borate buffer solutions as a function of the potential scan rate and pH from 4.80 to\n9.17. The results show that the oxide growth kinetics depends on pH of the electrolyte\nsolution and the total amount of irreversibly formed oxide under the potentiodynamic\nconditions decreases with decreasing buffer pH in accord with thermodynamic considerations.\nCathodic current corresponding to hydrogen evolution reaction diminishes in the presence of\nanodically modified electrode compared to bare zirconium.
Supported Phospholipid Bilayer at the Conductive Interface
Sokolová, Romana ; Kocábová, Jana ; Kolivoška, Viliam ; Gál, M.
The interactions of ethanol and flavonoid compounds with supported phospholipid bilayer\nwere studied by means of electrochemical methods and scanning probe techniques. The\nstability of a 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) phospholipid bilayer\nsupported on different types of conductive substrate was investigated. The relationship\nbetween the method of lipid deposition and the formation of several types of lipid structures\nincluding vesicles, hemimicelles, patches and single bilayers on the interface is discussed.
Oxidation of Bioflavonoids in Respect to their Chemical Structure
Sokolová, Romana ; Ramešová, Šárka ; Kocábová, Jana ; Degano, I.
The electrochemical oxidation of flavone luteolin, flavanone taxifolin and flavonols derived from quercetin was studied by cyclic voltammetry. Only small differences in the chemical structure of bioflavonoids resulted in extremely variable oxidation pathways and products. Products of oxidation and further decomposition were determined by HPLC-ESI-MS/MS and HPLC-DAD.
Comparison of Techniques for Single-Molecule Conductance Measurements of Expanded Pyridinium Molecules
Lachmanová, Štěpánka ; Hromadová, Magdaléna ; Sokolová, Romana ; Kocábová, Jana ; Gasior, Jindřich ; Mészáros, G. ; Lainé, P. P.
This work is focused on the comparison of two techniques of single-molecule conductance measurements: Scanning Tunneling Microscopy Break Junction technique and Mechanically Controlled Break Junction technique. The structure of studied compound 9-(pyridin-4-yl)benzo[c]benzo[1,2]quinolizino[3,4,5,6-ija][1,6]naphthyridin-15-ium allows the formation of the molecular bridge between two gold electrodes, which are connected to a source of the constant voltage in both of the used methods. The differences, advantages and disadvantages of both of the techniques will be discussed. Both techniques provided two values of conductance of studied compound depending on the experimantal conditions.
Electrochemistry of Flavonolignans in Acetonitrile and Dimethylsulfoxide
Sokolová, Romana ; Kocábová, Jana ; Fiedler, Jan ; Vacek, J. ; Marhol, Petr ; Vavříková, Eva ; Křen, Vladimír
This study is focused on investigation of oxidation pathways of silybin and 2,3-dehydrosilybin in nonaqueous solutions. The oxidation mechanism of both flavonolignans differs and depends strongly on their chemical structure. The cyclic voltammetry, UV/Vis and IR spectroelectrochemistry were used for identification of electrooxidation (semiquinone) intermediates. HPLC with diode array detection was applied for identification of oxidation and degradation products. Molecular orbital calculations supported the experimental findings.
Adsorpce 1,2-dipalmitoyl-sn-glycero-3-fosfocholin na Au(111) a HOPG
Kocábová, Jana ; Sokolová, Romana
Molekula 1,2-dipalmitoyl-sn-glycero-3-fosfocholin (DPPC) (Obr. 1.) 1 patří mezi fosfolipidy (zwitterion fosfoglycerid), které jsou používané pro přípravu liposomálních monovrstev. V literatuře se stále setkáváme se snahou vytvořit modelové membrány buněk, tak abychom byli schopni pochopit jejich mechanismus a kinetiku vzniku a následně je mohli využit v biotechnologických aplikacích 2,3.
Adsorpce fosfolipidů na mezifází
Sokolová, Romana ; Kocábová, Jana ; Parisová, Martina ; Navrátil, Tomáš ; Gál, Miroslav
V předkládaném příspěvku je diskutován vliv typu substrátu na tvorbu fosfolipidové vrstvy, ať už fosfolipidové dvojvrstvy nanesené na povrchu (supported phospholipids bilayer, SPB) nebo vrstvy vesikul fosfolipidu nanesené na povrchu (supported vesicular layer, SVL). Studium je zaměřeno hlavně na vlastnosti fosfolipidové vrstvy nanesené na polykarbonátovou membránu.
Stanovení fytohormonů v geneticky modifikovaných rostlinách Nicotiana pomocí diferenční pulsní voltametrie
Kocábová, Jana ; Sokolová, Romana ; Giannarelli, S.
Diferenční pulsní voltametrie byla použita pro stanovení IAA fytohormonu v rostlinných vzorcích pomocí skelno-uhlíkové elektrody. Detekční limit navrhované metody je 0,45 microg.ml-1. Stanovení elektrochemického IAA je selektivní a koncentrace IAA ve vzorku z geneticky modifikované rostliny Nicotiana langsdorfii byla stanovena v přítomnosti jiných hormonů jako kyseliny abscisové a některých cytokininů.
Electrochemistry of selected radiosenzitizer-etanidazole
Gál, Miroslav ; Híveš, J. ; Sokolová, Romana ; Hromadová, Magdaléna ; Kocábová, Jana ; Kolivoška, Viliam ; Pospíšil, Lubomír
The first electron transfer to radiosensitizer etanidazole (ETN) and ETN radical anion formation in buffered aqueous media was studied by means of voltammetric techniques and Electrochemical Impendance Spectroscopy (EIS). The heterogeneous electron transfer rate constant for the first reduction of ETN (radical anion production) k0 for the redox couple and so called E1,7 potential were calculated. The obtained values of k0 and E1,7 potential indicate that ETN compared to some other possible chemical radiosensitizers requires lower energy to accept the first electron during metabolic pathway.

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