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Proposal of topology of piezoceramic composite sensor
Dostal, Vojtěch ; Ševeček, Oldřich (referee) ; Majer, Zdeněk (advisor)
This master thesis deals with design and numerical modelling of piezoceramic sensor, which is placed on a rail, in order to generate electrical energy, which can be used for wireless monitoring of railway traffic and to monitor the condition of the railway. The thesis is divided into three parts. Theoretically background of piezoelectric energy harvesting is described in first part, where some previous application of piezoelectric generator in railway area are shown. In the second part, parametric analysis of numerical model is performed, which directly leads to finding best location on a rail, where piezoelectric generator should be placed. For this analysis the homogenized model of MFC sensor was used. Results of the numerical model were then compared with the results of the conducted experiment. The third part presented own design of piezoceramic sensor, which is placed onto most suitable location on a rail. Results from numerical analysis shown eligibility of using piezoceramic sensor to monitor the railway traffic.
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Analytical model of composite cantilever with SMART layer
Dostal, Vojtěch ; Ševeček, Oldřich (referee) ; Majer, Zdeněk (advisor)
This bachelor's thesis deals with analytical modelling of composite cantilever with smart layer. The structure is based on the real piezoelectric generator, which is a solid cantilever beam with a layer of piezoelectric material attached to its bottom and top. The first part of this bachelor's thesis summarizes the knowledge of the energy harvesting, the process under which harvesting of electric energy from the piezoelectric generator belongs. Some piezoelectric materials are mentioned and described afterwards. At first, analytical modelling is implemented on the homogeneous cantilever beam. Then, the relations for required characteristics are derived for laminate structure, which is structurally similar to the piezoelectric generator. One chosen parameter will be changeable. Due to the ties of relations, the required characteristics will change as well, which are for the piezoelectric generator strain and deflection.
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Vesicular roles of Arp2/3 nucleation-promoting factors
Dostál, Vojtěch ; Libusová, Lenka (advisor) ; Malínský, Jan (referee) ; Befekadu, Asfaw (referee)
F-actin is involved in key aspects of vesicular traffic, such as membrane deformation, tubulation and vesicle motion. Branching of F-actin is mediated by Arp2/3 but this complex must first be activated by so-called nucleation-promoting factors (NPFs). These factors play an essential role in the decision where and when branched actin should form on the membrane surface. The thesis focuses on the mechanisms which underlie localization and activation of NPFs, especially in terms of the phosphoinositide composition of the vesicle membranes. I show that one of the NPFs, the WASH complex, does not exclusively depend on the retromer complex for its membrane anchoring, as previously theorized. Rather, its understudied subunit SWIP enables the complex to independently bind to the membrane. I also present data showing that the WASH complex has essential roles in maintaining lysosomal function. Additionally, I elucidate the function of another NPF known as WHAMM in the ERGIC compartment, showing that it depends on the presence of myotubularin 9 for its ability to form membrane tubules. The thesis improves our understanding of the interface between the actin cytoskeleton and intracellular membrane system.
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Proposal of topology of piezoceramic composite sensor
Dostal, Vojtěch ; Ševeček, Oldřich (referee) ; Majer, Zdeněk (advisor)
This master thesis deals with design and numerical modelling of piezoceramic sensor, which is placed on a rail, in order to generate electrical energy, which can be used for wireless monitoring of railway traffic and to monitor the condition of the railway. The thesis is divided into three parts. Theoretically background of piezoelectric energy harvesting is described in first part, where some previous application of piezoelectric generator in railway area are shown. In the second part, parametric analysis of numerical model is performed, which directly leads to finding best location on a rail, where piezoelectric generator should be placed. For this analysis the homogenized model of MFC sensor was used. Results of the numerical model were then compared with the results of the conducted experiment. The third part presented own design of piezoceramic sensor, which is placed onto most suitable location on a rail. Results from numerical analysis shown eligibility of using piezoceramic sensor to monitor the railway traffic.
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The role of microtubule dynamics in cancer metastasis
Klubíčková, Natálie ; Čermák, Vladimír (advisor) ; Dostál, Vojtěch (referee)
Cancer is one of the main mortality causes worldwide, and the majority of cancer-related deaths occur due to metastasis. During the metastatic cascade, cancer cells acquire a specific and highly plastic phenotype that enables them to detach from the primary tumor and invade the surrounding tissue, migrate avidly, evade host immunity, survive in different hostile environments and colonize secondary sites to establish metastases. Changes in microtubule dynamics together with other parts of cell cytoskeleton regulation are crucial for cancer cells undergoing the metastatic process. In the first part of this thesis, I review critical moments of the metastatic cascade in relation to microtubule-associated signaling, while detailed information on important microtubule-associated proteins and their role in metastasis is provided in the second section. Keywords: Metastasis, microtubule, cancer, migration, microtubule-associated proteins.
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Tubulin post-translational modifications
Kropáčková, Veronika ; Bařinka, Cyril (advisor) ; Dostál, Vojtěch (referee)
Microtubules composed of αβ-tubulin heterodimers are an integral part of the cellular cytoskeleton of eukaryotic organisms. They participate in the cellular transport, determine the distribution of membrane organelles and help defining cellular polarity. Microtubules are part of dynamic structures such as mitotic spindle, but they also form stable structures such as flagellar and ciliar axonemes. Microtubules have many distinct functions in cells and tissues and therefore must differ from each other in some way. Post-translational modificationsof αβ-tubulin in microtubules are the major source of their diversity and collectively define so-called tubulin code. Twelve posttranslational modifications of tubulin/microtubules have been identified so far. Unraveling the mechanisms involved in post-translational modifications of tubulin/microtubules, including the identification of responsible enzymes, is an important source of understanding of the effects of these modifications on biological functions. Key words: tubulin, post-translational modificaton, microtubules, acetylation, tyrosination, polyamination, polyglutamylation
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Analytical model of composite cantilever with SMART layer
Dostal, Vojtěch ; Ševeček, Oldřich (referee) ; Majer, Zdeněk (advisor)
This bachelor's thesis deals with analytical modelling of composite cantilever with smart layer. The structure is based on the real piezoelectric generator, which is a solid cantilever beam with a layer of piezoelectric material attached to its bottom and top. The first part of this bachelor's thesis summarizes the knowledge of the energy harvesting, the process under which harvesting of electric energy from the piezoelectric generator belongs. Some piezoelectric materials are mentioned and described afterwards. At first, analytical modelling is implemented on the homogeneous cantilever beam. Then, the relations for required characteristics are derived for laminate structure, which is structurally similar to the piezoelectric generator. One chosen parameter will be changeable. Due to the ties of relations, the required characteristics will change as well, which are for the piezoelectric generator strain and deflection.
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Analysis of WASH complex component FAM21
Dostál, Vojtěch ; Libusová, Lenka (advisor) ; Žárský, Viktor (referee)
The dynamics and function of the actin cytoskeleton depends on polymerization and branching of actin filaments, an event that is stimulated by Arp2/3. Arp2/3-dependent branching is closely linked to the pentameric WASH complex which consists of WASH, strumpellin, SWIP, CCDC53 and FAM21. WASH complex is associated mainly with endosomes. It was traditionally localized to retromer-coated domains of early endosomes which enable sorting and recycling of endocytosed material. However, latest scientific data extend the role of WASH complex to other endosomal or even non-endosomal sites. Of all the subunits of the WASH complex, FAM21 is the most prominent hub for protein-protein interactions, thanks to its long unstructured C-terminal domain. In my diploma thesis FAM21 was localized to early and late endosomes and lysosomes of U2OS human cell line. Dictyostelium discoideum was then used as a model organism to investigate FAM21 protein interactions as well as the proteins associated specifically with the C terminal domain of FAM21. Results of the study shed new light on the complex network of FAM21 interactions and question the long-standing theories on the function of WASH complex in cells. Powered by TCPDF (www.tcpdf.org)
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Microtubule-active drugs: mechanism of action and resistance
Dostál, Vojtěch ; Libusová, Lenka (advisor) ; Rösel, Daniel (referee)
Microtubular cytoskeleton represents a target for a myriad of diverse chemical compounds, referred to as microtubule-active drugs. Produced by certain plants, animals or microbes, the substances often effectively elicit cell death - especially in animals and also in plants to a certain extent, but never in species which produce them to defend against their predators. Nowadays, several microtubule-active substances constitute hallmarks of anti-cancer treatment and agricultural weed control. There is an enormous sum of knowledge about the action of paclitaxel (taxol), vinca alkaloids and colchicine, three best-known microtubule active compounds used in medicine, and new research often challenges the previously accepted theories. This work investigates the mechanism of action of microtubule-active drugs from the angle of biochemistry and cell biology, as well as from the physiological standpoint. Effects on microtubule levels and dynamics and the path towards the cell death are reviewed. In the last chapter, attention is given to drug activity in both animal and plant bodies and, finally, to drug-producing plant species which often show substantial resistance.
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