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Interaction of 7,8-dihydroxyflavone with physiological metals
Streďanská, Aneta ; Mladěnka, Přemysl (advisor) ; Červený, Lukáš (referee)
Charles University Faculty of Pharmacy in Hradec Králové Department of Pharmacology and Toxicology Student: Aneta Streďanská Supervisor: prof. Přemysl Mladěnka, Pharm.D., PhD. Consultant: Zuzana Lomozová, Pharm.D., PhD. Title of thesis: Interactions of 7,8-dihydroxyflavone with physiological metals 7,8-dihydroxyflavone belongs to the phenolic substances collectively referred to as flavonoids. Flavonoids are bioactive components abundantly distributed in the daily diet with the ability to modulate health and disease through miscellaneous mechanisms including their antioxidant activity. However, they can also exhibit prooxidative effects under certain conditions. Due to this fact, which is related to individual factors, i.e. presence of various substitutions on the flavonoid come, it is therefore essential to understand the redox behavior based on the relationship between structure and effect and to understand their physiological, pharmacological and thus also potential toxic properties. The interaction with physiological metals is determined by the structure of the molecule through the dihydroxy moiety in positions 7 and 8. These mentioned metals are essential for many biochemical processes in biological systems. Their homeostasis is strictly regulated in the human body and disruption of this...
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Mg-hydroxyapatite composite materials prepared by powder metallurgy
Řičánek, Adam ; Doskočil, Leoš (referee) ; Buchtík, Martin (advisor)
This bachelor thesis focuses on the preparation of magnesium-hydroxyapatite composite by powder metallurgy methods. The theoretical part of bachelor thesis deals with magnesium, magnesium alloys and magnesium materials. Furthermore, the theoretical part of the bachelor thesis deals with the basics of powder metallurgy, processing of materials prepared by powder metallurgy and metal matrix composites. In the experimental part of the bachelor thesis, two series of composites were made with different quantities of hydroxyapatite. Composites were made by mixing Mg with filler and by mixing and milling Mg with filler. Both series of composites were characterised by investigation of microstructure and element composition, hardness, compressive strength and corrosion resistance. Composites of mixed and milled series showed a highly homogenous structure. Hardness, compressive strength and corrosion resistance increased with increasing amounts of hydroxyapatite. Composites of mixed series showed heterogeneous structures. Hardness did not increase with increasing amount of hydroxyapatite. Corrosion resistance slightly increased with increasing amount of filler. Compression strength decreased with the increasing amount of filler due to lower cohesion and incompactness of the structure.
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Influence of alloying elements on the solubility of titanium in magnesium alloys
Matocha, Martin ; Buchtík, Martin (referee) ; Březina, Matěj (advisor)
This bachelor's thesis examines the influence of alloying elements on the solubility of titanium in magnesium alloys. In the theoretical part, a literature review was conducted on the topics of the creation, composition, processing, and brief analysis possibilities of magnesium alloys, with an emphasis on the potential for alloying magnesium alloys with titanium. The experimental part focused on the preparation of systems with various compositions to achieve the integration of titanium into the magnesium alloy. After preparation of the samples of the given systems, their analysis was performed using SEM/EDS and XRD. Based on the ongoing results of the samples analysis, efforts were made to optimize the holding time of the samples of the given system at a temperature of 905°C. It was found that during the stabilization of the modification of titanium, it is possible to achieve mixing of titanium, zinc, and magnesium. The condition for the formation of the modification of titanium is the highest possible temperature allowed by the system. However, the temperature must exceed at least 881°C. The stability of the modification of titanium is also supported by the absence of alloying elements that promote the stability of the modification of titanium. The mixture of elements in the aforementioned system has not yet been described in the scientific literature.
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Effect of EDTA on properties of layered double hydroxides deposited on Mg substrates
Tkadlec, Tomáš ; Doskočil, Leoš (referee) ; Buchtík, Martin (advisor)
The subject of the bachelor's thesis was the preparation and characterization of MgAl LDH coatings on Mg substrates prepared by powder metallurgy with the aim of improving corrosion resistance. The coatings were prepared in a reaction mixture with various concentrations of EDTA. The corrosion resistance of the coated samples was analyzed using potentiodynamic measurements and compared with uncoated Mg. The sample prepared with a 5mM concentration of EDTA in the reaction mixture showed the best corrosion resistance. Higher concentrations of EDTA led to a deterioration of corrosion properties. The morphology and structure of the coatings and the elemental composition were described using electron microscopy and EDS analysis. Phase analysis was performed using X-ray diffraction (XRD). It was demonstrated that EDTA affects the structure of LDH coatings. The concentration of EDTA above 25mM in the reaction mixture results in the formation of Al(OH)3 coatings.
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Preparation and characterization of layered double hydroxides on Mg substrates prepared by powder metalurgy
Kobzinková, Eliška ; Doskočil, Leoš (referee) ; Buchtík, Martin (advisor)
This thesis deals with the preparation and characterization of double-layered hydroxides (LDH) on Mg substrates prepared by powder metallurgy. The theoretical part deals with magnesium, magnesium powder metallurgy, and LDH coatings and methods of their preparation with a focus on MgAl-LDH. The theoretical part is concluded with a research study of current research in the field of preparation of LDH coatings on magnesium substrates and the influence of process parameters on the properties of coatings. The experimental part covers the process of optimization of MgAl-LDH on Mg samples prepared by powder metallurgy. In particular, the morphology and structure of the coatings and their elemental composition were evaluated. The evaluation was carried out using a scanning electron microscope (SEM) with an energy dispersive spectrometer (EDS). The optimized MgAl-LDH coatings were also evaluated for electrochemical corrosion properties by potentiodynamic tests in Hank's solution corrosion environment and phase analysis by X-ray diffraction (XRD).
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Mechanical properties of magnesium alloy AZ91E prepared by ECAP method
Darida, Jiří ; Válka, Libor (referee) ; Pantělejev, Libor (advisor)
This thesis deals with mechanical and fatigue properties of magnesium alloy AZ91 processed by EX-ECAP method. This method involves the application of extrusion followed by equal-channel angular pressing. To obtain basic mechanical characteristics, the tensile test were carried out at room and elevated temperatures. Further the fatigue tests were performed and obtained data were used to compile S-N curve. The work also includes metallographics analysis of microstructure and fractographic analysis of fracture surfaces of tensile and fatigue test specimens.
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Zn and Mg based bulk materials for biomedical applications
Ryšťák, Jaroslav ; Fintová, Stanislava (referee) ; Doležal, Pavel (advisor)
Topic of the diploma thesis is Zn-Mg bulk material preparation by powder mixtures sintering at hot pressing. Structure, porosity and physically mechanical properties of prepared bulk materials were evaluated. Obtained results and their interpretation were served as feedback for following optimization of individual processing parameters of bulk materials preparation. Solution of diploma thesis is focused on study and control of processes during bulk material preparation and processes description from physical-chemical point of view with respect to structure creation and final material properties.
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Nanocomposites with a metal matrix
Chlupová, Monika ; Kohout, Jan (referee) ; Zapletal, Josef (advisor)
This baechelor thesis is focused on metal matrix nanocomposites (MMNCs), whose research has started recently. In the first part of this thesis are generally defined composite materials, the larger part is dedicated to metal matrix composites (MMCs), on which are described the strengthening mechanisms that are also applied to MMNCs. The second part of the thesis is focused specifically on MMNCs. The concept of MMNCs and their distribution is defined first, followed by a definition of the reinforcement that can be used for the production of MMNCs. There are also described the posibilities for the production of these reinforcing phases, and their influence on the structural and mechanical properties of the final MMNCs. This section is followed by a description of possible processes of MMNCs production with their advantages and limitations. The last part outlines how research and development of these materials should be carried out in order to be commercially produced and used in the future.
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The significance of magnesium for human health
Škeřík, Jan ; Hrstka, Miroslav (referee) ; Vránová, Dana (advisor)
Aim of this bachelor thesis was to compare different forms of magnesium. The characteristics and history of magnesium was briefly described at the beginning of the theoretical part. The following chapters explain the importance of magnesium in the body, hypomagnesemia, hypermagnesemia. Another section describes magnesium effect on various diseases, increased intake of magnesium and magnesium metabolism. The ninth and tenth chapter describes the effects of nicotine and alcohol on the metabolism of magnesium and magnesium content in drinking and mineral water. Conclusion of the theoretical part is dedicated to the description of the analytical methods of dosage forms. At the heart of the practical part was using several commonly used methods to determine best magnesium addition. It was the method of determination of the mass uniformity, determining magnesium contents in the tablet, the determination of disintegration, dissolution determination and hardness determination.
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