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Vývoj elektrochemického glutamátového biosenzoru
Doležalová, Julie ; Solich, Petr (advisor) ; Polášek, Miroslav (referee)
DEVELOPMENT OF A GLUTAMATE ELECTROCHEMICAL BIOSENSOR Julie Doležalová (Department of Analytical Chemistry, Faculty of Pharmacy, Charles University in Prague) In cooperation with: Sofia A.L.P. Gomes, Alberto N. Araújo (Department of Physical Chemistry, Faculty of Pharmacy, University of Porto) L-Glutamic acid and monosodium glutamate are used to enhance flavour in food prepared at home, restaurants, and by the food processing industry [1]. Glutamate also plays an important role in many metabolic processes. Nevertheless its use is being kept under certain limits as some people have experienced adverse effects, such as stiffness and tension, after its ingestion. Moreover, some studies demonstrate its connection with the appearance of neurological manifestations, such as Parkinson's and Alzheimer's disease. The determination of L-glutamic acid is therefore of major importance. In this work a novel L-glutamate biosensor was developed using a dehydrogenase enzyme (L-glutamate dehydrogenase). These redox enzyme requires for its activity nicotinamide (NAD(P)+ /NAD(P)H) coenzyme, which reduced form was electrochemically regenerated by the water-soluble dye, methylene green. Graphite electrodes were modified with a poly(methylene green) thin film by means of methylene green electrochemical polymerization...
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Evaluation of Celluloses and Maize Starch by the Creep Test Method
Doležalová, Julie ; Řehula, Milan (advisor) ; Špaček, Vladimír (referee)
Evaluation of Celluloses and Maize Starch by the Creep Test Method The aim of this work was to consider the appropriateness of using the creep test for evaluation of visco-elastic characteristics of pharmaceutical fillers and to compare these properties. Pharmaceutical powders involved in this assessment were powdered cellulose (Vitacel A 300), hydroxyethylcellulose (HEC, Natrosol 250), hydroxypropylcellulose (HPC, Klucel EF), hydroxypropylmethylcellulose (HPMC, K 100) and maize starch. The powders were compressed with a material-testing machine T1-FRO 50 by compression forces of 0,25; 0,5; 1; 2; 3; 4; 5; 7,5; 10 and 15 kN. Compression data for each tablet were then recorded by a software connected to the compressing machine. The recorded data, such as die displacement and time, were transferred into relation between creep compliance (J) and time. Obtained values were then used for calculating the parameters such as immediate elasticity (E1), retarded elasticity (E2), plasticity (P1) and factor of plasticity (FP). To summarize all results, we can say that hydroxypropylcellulose has the highest values of elasticity and the lowest values of plasticity among all tested powders. Conversely hydroxypropylmethylcellulose shows the lowest elasticity and powdered cellulose presents the most plastic...
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Vývoj elektrochemického glutamátového biosenzoru
Doležalová, Julie ; Solich, Petr (advisor) ; Polášek, Miroslav (referee)
DEVELOPMENT OF A GLUTAMATE ELECTROCHEMICAL BIOSENSOR Julie Doležalová (Department of Analytical Chemistry, Faculty of Pharmacy, Charles University in Prague) In cooperation with: Sofia A.L.P. Gomes, Alberto N. Araújo (Department of Physical Chemistry, Faculty of Pharmacy, University of Porto) L-Glutamic acid and monosodium glutamate are used to enhance flavour in food prepared at home, restaurants, and by the food processing industry [1]. Glutamate also plays an important role in many metabolic processes. Nevertheless its use is being kept under certain limits as some people have experienced adverse effects, such as stiffness and tension, after its ingestion. Moreover, some studies demonstrate its connection with the appearance of neurological manifestations, such as Parkinson's and Alzheimer's disease. The determination of L-glutamic acid is therefore of major importance. In this work a novel L-glutamate biosensor was developed using a dehydrogenase enzyme (L-glutamate dehydrogenase). These redox enzyme requires for its activity nicotinamide (NAD(P)+ /NAD(P)H) coenzyme, which reduced form was electrochemically regenerated by the water-soluble dye, methylene green. Graphite electrodes were modified with a poly(methylene green) thin film by means of methylene green electrochemical polymerization...
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