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Biodegradable Mg-based materials for stents and bone implants
Zemková, Mária ; Král, Robert (advisor) ; Stráská, Jitka (referee)
The bachelor thesis is focused on the effect of mechanical processing rotary swaging (RS), specifically on the microstructure, mechanical properties and corrosion properties. The investigation was performed on the magnesium alloy AE42 with a different number of RS passes, which can be useful for medical applications. RS is more efficient and cheaper alternative to different material processing methods producing fine-grained struc- ture. Fine-grain structure with grain boundaries with high angle misorientation was achieved by this process. Microstructure was inhomogeneous - the grain size decreased from the surface to the center. An improvement of mechanical properties with the increase in the number of swaging steps was observed. Processing also led to a decrease in corrosion resistance in this alloy. Microstructure development was investigated by electron microscopy scanning. Development of mechanical properties was characterized by compression deformation tests and microhardness measurements. Linear pola- rization method was used for the interpretation of corrosion resistance. 1
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Rationaly Aspectof Antibioticotherapy in Patients treated with Dialysis.
Vrběcká, Radka ; Vlček, Jiří (advisor) ; Zemková, Marcela (referee)
Ždímalová R.: Analysis of consumption of antibiotics in patients treated with dialysis, Charles University in Prague, Faculty of Pharmacy, Department of social and clinical pharmacy, Hradec Králové 2009, 73 pages. Introduction and objective: This study observes consumption of antibiotics in patients treated with dialysis in The University Hospital of Hradec Králové in years 2006 and 2007. Pilot project investigate, which kind of antibiotics used dialyzed patients (DP) the most of all. Studies further compare information from two sets of DP from Czech Republic (Group I) and Lithuania (Group II) in specific aspects of antibiotic's consumption. Methodology: Retrospective analysis resulting from data evaluation from Nephris database of University Hospital of Hradec Králové by DP (2006&2007). Set of data of the Group II from Clinics of Kaunas Medical University - Lithuania was process by retrospective analysis too. GLMZ mode was used for statistical analysis. Results: Group I: from average number of 125 hospitalized patients were treated by antibiotics 71 (57%) patients. Both men and women have the same representation in the group, patients undergoing dialysis mostly in higher age, what has been discovered by mean age 66 years. From 71 patients treated with antibiotic was prescribed the most of all...
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Mechanical properties of WN43 magnesium alloy prepared by spark plasma sintering
Knapek, Michal ; Minárik, P. ; Greš, A. ; Zemková, M. ; Cinert, Jakub ; Král, R.
The spark plasma sintering (SPS) method was used to prepare bulk materials form WN43 magnesium alloy atomized powder. Compression tests were carried out in order to investigate the effect of different sintering regimes (10 min at 400, 450, or 500 degrees C) on the mechanical properties of the material. Furthermore, complementary in-situ acoustic emission (AE) recording was employed to reveal the dynamics of deformation processes during compression. It was shown that by increasing the sintering temperature, the ultimate compressive strength and ductility were significantly improved. The AE data and microstructure observations suggest that pronounced twin nucleation takes place around the yield point whereas twin growth and dislocation activity are the dominant deformation mechanisms in the later stages of deformation.
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Magnesium alloys designed for medical applications
Zemková, Mária ; Minárik, Peter (advisor) ; Vojtěch, Dalibor (referee)
Title: Magnesium alloys designed for medical applications Author: Mária Zemková Abstract: This Master thesis is focused on the influence of hot extrusion and equal channel angular pressing (ECAP) on the microstructure, mechanical and corrosion properties of magnesium alloys. Investigated materials include three magnesium alloys with the addition of neodymium and/or yttrium elements - N3, W3 and WN43, as a potential material for medical applications. Moreover, the influence of alloying elements in solid solution state was studied. Microstructure development was characterized by scanning electron microscopy together with transmission electron microscopy and X-ray diffraction. Mechanical properties was studied by compression deformation tests in two perpendicular directions and by microhardness tests. The linear polarization method was used to study corrosion resistance. The processing though ECAP resulted in grain refinement in all three alloys. Ultra-fine grained microstructure was achieved in W3 and WN43 alloy. The high degree of recrystallization during ECAP caused the formation of high-angle grain boundaries in all three alloys. Weak texture evolution was maintained during both processings. A different initial fraction of intermetallic phases before extrusion led to significant changes of microstructure...
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Linguistic -like approaches in geomics and linguistic metaphor in biology
Nohejlová Zemková, Michaela ; Flegr, Jaroslav (advisor) ; Faltýnek, Dan (referee) ; Kejnovský, Eduard (referee)
In this work we present articles which are connected by the topic of linguistic-like approaches in genomics, which allow to treat genetic sequences as a "text" containing potential "words" (oligonukleotides, oligopeptides) of length n. Such an approach stands on the border of quantitative and qualitative analysis and, contrary to standard comparative bioinformatics methods, it is possible to compare phylogenetically distant individuals. Central article of my work (Zemková et al., 201..) is an analysis of peptide vocabularies of parasites and free-living organisms which showed significant differences in diversity of 4-6 amino acids long peptides of these compared groups. Parasites generally display reduction of pentapeptides, which is partly compensated by increased diversity of hexapeptides. This result is in accordance with our a priori hypothesis that parasites use immune evasion strategy to escape from MHC-based immunity system of its vertebrate host. Results also suggest that the length of key region for peptide recognition is about 4-5 amino acids and hence only short part of longer peptide bound in MHC participate on reaction with T-receptor. In other two articles which arose as a product of cooperation with Prof Trifonov from the University of Haifa, we again used an analysis of genomic...
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New wilderness and its theoretical context on the example of Rohan island
Hořejší, Johana ; Hladký, Vojtěch (advisor) ; Nohejlová Zemková, Michaela (referee)
New wilderness is a term denoting a particular kind of environment which is considerably modified by human activity and then abandoned. These places are left to their own development defined mostly by natural processes. This work describes the phenomenon of new wilderness both in Czech and international context. It attempts to capture not only the general nature of new wilderness but also to point out various features which are provoked by its character. Subsequently it discusses the theory of Umwelt by Jakob von Uexküll describing the relation of individual to the world and treating the space as perceived individually. Second part of this work is dedicated to concrete example of new wilderness - Rohan island in Prague. It summarizes its history and natural conditions. The concepts of Umwelt and heterotopia are then applied to this locality. The two theories in question, conceiving space in a specific way, develop further the complexity and richness of the phenomenon of new wilderness.
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Biodegradable Mg-based materials for stents and bone implants
Zemková, Mária ; Král, Robert (advisor) ; Stráská, Jitka (referee)
The bachelor thesis is focused on the effect of mechanical processing rotary swaging (RS), specifically on the microstructure, mechanical properties and corrosion properties. The investigation was performed on the magnesium alloy AE42 with a different number of RS passes, which can be useful for medical applications. RS is more efficient and cheaper alternative to different material processing methods producing fine-grained struc- ture. Fine-grain structure with grain boundaries with high angle misorientation was achieved by this process. Microstructure was inhomogeneous - the grain size decreased from the surface to the center. An improvement of mechanical properties with the increase in the number of swaging steps was observed. Processing also led to a decrease in corrosion resistance in this alloy. Microstructure development was investigated by electron microscopy scanning. Development of mechanical properties was characterized by compression deformation tests and microhardness measurements. Linear pola- rization method was used for the interpretation of corrosion resistance. 1
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