National Repository of Grey Literature 178 records found  beginprevious159 - 168next  jump to record: Search took 0.03 seconds. 
Preparation of silicalite-1 composite membranes
Hrabánek, Pavel ; Bernauer, B. ; Zikánová, Arlette ; Krystl, V. ; Kočiřík, Milan
Silicalite-1 crystal layers were synthesised on stainless steel and ceramic supports. The stainless steel supports manufactured by Trumem Int. (USA) and ceramic supports manufactured by Carborundum Electrite (Czech Republic) were chosen to prepare silicalite-1 composite membranes. In the case of stainless steel silicalite-1 composite membrane, the applied synthesis process has been recently developed by Gora et.al [1]. It was observed that the presence of silicalite-1 seeds influenced the membrane quality. A number of crystallization steps also played an important role. Ceramic silicalite-1 composite membranes were prepared on ceramic supports with the layers of randomly oriented silicalite-1 crystals. The disadvantage of the ceramic supports was their large pore size distribution and roughness of the surface. For this reason, several coating steps using ceramic glaze had to be used to reduce the pore size distribution and non-uniformity of the surface.
The use of composite graphite electrode for voltammetric determination of phenylglyoxylic acid
Šenholdová, Z. ; Navrátil, Tomáš ; Shanmugam, K. ; Barek, J. ; Žák, J.
A composite electrode prepared from graphite powder and epoxy resin was applied as a working electrode for the determination of phenylglyoxylic acid (one of the metabolites of styrene) in human urine. Cathodic differential pulse stripping voltammetry was used and optimum conditions have been found giving the limit of determination about 5 mg L-1. All results were compared with those obtained using hanging mercury drop electrode. For the confirmation of suggested mechanism of the electrochemical reaction the elimination voltammetry with linear scan was used.
Voltammetric determination of genotoxic compounds using solid amalgam electrodes
Barek, J. ; Čížek, K. ; Fischer, J. ; Navrátil, Tomáš ; Josypčuk, Bohdan
Possibilities of voltammetric determinations of genotoxic organic compounds for environmental purposes were studied. Traditional mercury electrode was replaced by solid amalgam electrodes. It is possible to conclude that the obtained results are comparable with those, obtained on other types of electrodes.
Creatine fortification in relation to homocysteinemia
Kohlíková, E. ; Petr, M. ; Šenholdová, Z. ; Navrátil, Tomáš ; Heyrovský, Michael ; Přistoupilová, K. ; Přistoupil, T. I.
Some people supplement their diet by high doses of creatine (CR) to increase their muscle performace. In this way, they intensify the biochemical processes on cell membranes. The water thus formed is retained in the cells, which increases the body mass. The organism must remove exogenously added CR, probably in a similar way as in removing xenobiotics via oxidation with cyt.P450 to 2C units to cooperation with GSH. Our new simple and cheap voltammetric method enables to estimate thiogycolic (TDGA), the natural product of oxidative catabolism of thiocompounds, excreted to urine in regular catabolic processes.
Different metabolic pathwazy of the origin of hyperhomosysteinemia
Přistoupilová, K. ; Přistoupil, T. I. ; Navrátil, Tomáš ; Heyrovský, Michael ; Šenholdová, Z. ; Kohlíková, E. ; Petr, M.
Our voltammetric method of estimation of thiodiglycolic acid (TDGA) in urine was used in case of a woman suffering from rare inborn inability to metylate homocysteine (HoCySH). The aim of this pilot study was to shed more light on the interrelationship among vitamin B.sub.12./sub., folates, and betaine used for her cure. On the basis of the achieved results we were able to modify our earlier published metabolic scheme. It comprises 3 metabolic pathways starting from serine, and three metabolic pathways starting from HoCySH.
Výzkum atomových vlastností s použitím ionizačního potenciálu a Zlatého poměru
Heyrovská, Rajalakshmi
It was recently shown, that the Golden ratio divides the Bohr radius of hydrogen into the Golden sections due to electrostatistic reasons.
Voltammetric behavior of electrodes on the base of heterogenous silver and graphite composites
Navrátil, Tomáš ; Kopanica, Miloslav ; Šebková, Světlana
The voltammetric behavior of electrodes based on heterogenous silver and graphite composites was tested in this work. Such electrodes are a silver composite electrode, which contains a mixture of silver and graphite powder dispersed in metacrylate resin, and a graphite composite electrode formed by graphite powder in epoxy resin. The use of composite electrodes offers very good alternative to the use of mercury electrodes.

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