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Vliv lezecké výkonnosti na energetickou náročnost lezení
Kodejška, Jan ; Baláš, Jiří (vedoucí práce) ; Malý, Tomáš (oponent)
Cílem práce bylo posoudit vztah mezi lezeckou výkonností a energetickou náročností při lezení prostřednictvím specifického submaximálního testu. Výzkumný soubor se skládal z dvaceti šesti lezců (věk 26,8 ± 3,3 roku, tělesná hmotnost 70,6 ± 6,2 kg, výška 177,6 ± 6,5 cm). Lezci byli záměrně vybráni tak, aby jejich výkonnost pokryla co nejvíce celou stupnici obtížnosti UIAA (Union Internationale des Associations d'Alpinisme). Výkonnost lezců byla dána aktuálně nejvyšším přelezem ve stylu RP (Red point). Výkonnost lezců se pohybovala v rozsahu od 4 do 10 stupně UIAA. Lezci byli podrobeni submaximálnímu lezeckému testu, který trval 3 minuty v jednom sklonu. Pohybovali se konstantní rychlostí 25 kroků . min-1 po lezecké cestě, kterou již předem znali, přičemž sklon se po 3 minutách změnil z 90ř na 105ř. VO2 (spotřeba kyslíku), SF (srdeční frekvence) a VE (minutová ventilace) znatelně korelují s lezeckou výkonností RP (90ř, VO2, r = - 0,82; SF, r = -0,66, VE, r = - 0,77; 105ř, VO2, r = - 0,84; SF, r = -0,78; VE, r = - 0,80 ). Dechová frekvence během submaximálního lezení se pohybovala okolo 25 dechů . min-1 , což poukazuje na souvislost s lezeckou rychlostí. VO2 během submaximálního lezení lze využít pro hodnocení ekonomiky pohybu. Klíčová slova sportovní lezení, submaximální test, spotřeba kyslíku
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Hemoglobin-mediated oxidation of marine liposomes
Škrabalová, Lada ; Mozuraityte, Revilija (oponent) ; Rustad, Turid (vedoucí práce)
The objective of this work was to study the kinetics of lipid oxidation catalyzed by bovine methemoglobin and to evaluate the effects of different experimental conditions and different antioxidants (EDTA, ascorbic acid, caffeic acid, a-tocopherol, d-tocopherol, astaxanthin and L-ascorbic acid-6-palmitate) on the methemoglobin-mediated lipid oxidation in a marine phospholipid liposome model system. The oxygen uptake was used for monitoring lipid oxidation at pH 5.5 and 30 °C. The type of prooxidant and the concentration of both prooxidant and antioxidant (AOX) were found to be very important factors in the evaluation of the antioxidant activity in the liposome model system. Another important factors are the structure of the antioxidant molecule, its hydrophility/lipophility and its location in the system. All antioxidants, except 0.1 % of astaxanthin and 0.1 % of ascorbyl palmitate, inhibited metHb-induced lipid oxidation in all tested concentrations of the AOX. The efficiency of the AOX increased with their increasing concentration. 0.1 % of astaxanthin had no effect on the oxidation of liposomes. 0.1 % of ascorbyl palmitate had a prooxidative effect which can be explained by the prooxidative action of ascorbyl radical, which could promote hydroperoxide scission. Free iron released from metHb contributed little to metHb-mediated lipid oxidation in liposomes, whereas part of the prooxidant activity of metHb was attributed to the formation of singlet oxygen (metHb as a photosensitizer). The antioxidative activity of astaxanthin, ascorbyl palmitate, and tocopherol can be partly attributed to their singlet oxygen quenching ability. However, the main prooxidative mechanisms of metHb are suggested to be decomposition of lipid hydroperoxides, generating free radicals, and formation of hypervalent forms of Hb. EDTA inhibited oxidation of liposomes by chelating transition metals in liposomes and chelating free iron from the metHb solution. The reduction of hypervalent forms of Hb seems to be a very important antioxidant mechanism and was found to be attributed to ascorbyl palmitate, ascorbic acid (AsA) and caffeic acid (CaA). AsA, CaA, tocopherols and astaxanthin inhibit metHb-mediated lipid oxidation by scavenging of lipid radicals. No significant effect of hydrogen peroxide on the oxidation of liposomes was observed. The oxidation was slightly inhibited due to thermal treatment of metHb solution. A significant inhibition of oxygen uptake rate was observed in liposomes containing TPP (triphenylphosphine), which suggests that the heme-mediated lipid oxidation in liposomes is dependent on the presence of pre-existing lipid peroxides. The outcomes of this work can be used for the study of oxidation of liposome solutions, cell membranes and oil-in-water emulsions stabilized by phospholipids; the results contribute to understanding the prooxidant and antioxidant mechanisms and factors that influence oxidation in these systems.
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Evaluation of antioxidant effect using different analytical methods
Kristinová, Věra ; Mozuraityte, Revilija (oponent) ; Rustad, Turid (vedoucí práce)
The objective of the diploma thesis is to evaluate antioxidant effects of five different compounds that have a potential as food antioxidants (propyl gallate, caffeic acid, ferulic acid, p-coumaric acid and L(+)-ascorbic acid) by means of four conventional antioxidant capacity assays (FC, FRAP, DPPH, ABTS), and in a liposome model system using free iron (Fe2+, Fe3+) and bovine hemoglobin as prooxidants, with special focus on different concentration levels of the tested compounds in the system. The oxygen uptake is used for continuous monitoring lipid oxidation at pH 5.5 and 30°C. The outcomes of this work contribute to better understanding the basic pro- and antioxidant mechanisms and factors influencing oxidation of cell membranes, liposome solutions, and oil-in-water emulsions stabilized by phospholipids.
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