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Synthesis and properties of novel vitrimers from biobased feedstock
Kopilec, Ondrej ; Sedláček, Ondřej (advisor) ; Strachota, Adam (referee)
In this work, new materials based on dynamic polymer networks, also called vitrimers, were developed. These polymer networks have been developed from previously unused materials based on renewable raw materials, to maximize the renewable carbon content. The main starting monomer was based on D-isosorbide, which is prepared from starch. The latter was modified to bis-acetoacetate and used as the main building block of the networks. Di- and tri-functional amines of various origins were used as crosslinking agents - renewable sources based and for comparison, petroleum-based products. In order to get the best possible insight into the influence of the individual monomers on the final properties of the vitrimers, materials with 1:1 and 3:1 molar ratios of di- and tri-amines were developed. The prepared networks contained vinylogous urethane-type bonds - with a very low activation energy required for transamination reactions, which allows the vitrimers to retain their mechanical properties even after multiple recycling. In the case of this work, a 10% excess of free amine groups was maintained. The prepared materials in this thesis exhibit behaviour of vitrimers - network structure of thermosets and processability of thermoplastics. This was proven by thermal stability tests, tensile tests and tests...
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Parental care in crocodylians with an emphasis on acoustic communication between parent and young
Míka, Milan ; Frýdlová, Petra (advisor) ; Sedláček, Ondřej (referee)
Parental care for offspring encompasses a variety of behaviors aimed at increasing the offspring's survival rate. However, as the care of the offspring requires a lot of energy it raises a conflict between the parents. It would be more advantageous for each parent to leave a larger portion of parental care to the other. This would reduce the costs associated with care while increasing the success of gene transmission through offspring. This bachelor thesis describes parental care in several selected groups of animals. It reports the most common forms of parental care in these groups and, through individual examples, points out more complex or unusual forms and types of reproductive behavior. Examples are selected with consideration of similarities or differences with parental care in crocodiles. In the second part of this work, I focus on the order of Crocodylia, where parental care and acoustic communication are key elements of reproductive behavior and often determine the lives of crocodile offspring. I highlight similarities between crocodiles and their closest relatives, birds (Aves). Emphasis is placed on the analogy between crocodiles and birds and my observations suggest possibilities of ancestral behavior for the order Crocodylia and the entire group Archosauria. The result of the work is a...
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Targeted azole prodrugs with antifungal activity
Černá, Lucie ; Baszczyňski, Ondřej (advisor) ; Sedláček, Ondřej (referee)
Invasive fungal infections (IFIs), mostly caused by Aspergillus or Candida species, represent a severe global threat. IFIs are serious diseases of great concern especially in immunocompromised patiens, annually leading to more than 1.7 million deaths.1 Despite its seriousness, there is insufficient amount of available antifungal therapeutics. Current antifungal treatments rely mainly on azole drugs which often suffer from increased toxicity, low bioavailability and drug resistance, among others.2 Therefore, we aim to develop novel antifungals in the form of azole prodrugs which would selectively target specific fungal enzymes and would ideally avoid undesired off-target effects. Our designed prodrugs contain selected azoles, modified by the attachement of a self-immolative (SI) linker to a specific carbohydrate through a glycosidic bond. Such glycosidic bond should undergo cleavage by extracellular fungal glycosidases, resulting in release of the azole drug directly at the site of fungal infection. Keywords: azole, antifungal, prodrug, targeted delivery
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Synthesis of novel fluorinated tetrazines for selective cell labeling via metal-free "click" reactions
Výbošťoková, Júlia ; Sedláček, Ondřej (advisor) ; Baszczyňski, Ondřej (referee)
This diploma thesis deals with the synthesis and characterization of novel phenyltetrazine fluorinated compounds that contain a fluorinated substituent in the ortho, meta or para position with respect to the tetrazine group. These compounds are used in bioorthogonal cell labeling through so-called "click" reactions. Change in the chemical shift of the fluorinated substituent signal in 19 F NMR after the "click" reaction will allow in vitro/in vivo monitoring of labeling using 19 F MRI. For this reason, the spatial proximity of the fluorinated substituent to the tetrazine part of the molecule is important in terms of real-time detection of the "click" reaction itself. In the beginning, commercially unavailable aromatic nitriles were synthesized. In the next step, tetrazine synthesis was performed from synthesized and commercially available starting nitriles by "Pinner-like" reaction. This involved a reaction with acetonitrile or (3,3,3)-trifluoropropionitrile and hydrazine monohydrate in the presence of Lewis acid Zn(OTf)2. Reactions with ortho-substituted phenyltetrazines did not yield any positive results. Conversely, the synthesis of meta and para-substituted phenyltetrazines was successful. All successfully synthesized tetrazines undergo IEDDA "click" reactions with trans-cyclooctenol. Keywords:...
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The effectivity of ecoducts for wildlife crossing of landscape fragmented by a highway network
Leštinová, Eliška ; Sedláček, Ondřej (advisor) ; Uhlíková, Jitka (referee)
Ecoducts or wildlife overpasses are migration objects that are often built not only in the Czech Republic, but in Europe as well. They enable animals to safely cross an obstacle, for example a road or a railway. Furthermore, ecoducts enlarge the home ranges of species, ensure gene flow between populations, and influence interspecies interactions. Ecoducts built in the Czech Republic are often criticized, especially because of their high cost and low efficiency. Majority of the existing studies compare ecoducts with other types of migration objects, such as underpasses, and often focus on selected aspects of these structures, such as their dimensions or location. There are very few summarizing studies focusing solely on ecoducts and what influences their permeability for animals. In this paper, I summarize what species are using ecoducts in Europe and North America, and I discuss how is the use of an ecoduct by animals affected by anthropogenic disturbances, design of the ecoduct, and its location in the landscape. Lastly, I describe monitoring methods used when studying wildlife overpasses. In the end, I summarize gained knowledge and list gaps in the existing research.
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Macromolecular avenues for the creation of bio-inspired hierarchically structured surfaces
Wang, Yu-Min ; Pop-Georgievski, Ognen (advisor) ; Kostka, Libor (referee) ; Sedláček, Ondřej (referee)
Biomedical applications often rely on surface adherent architectures such as polymer brushes to prevent adverse nonspecific interactions between materials used in biomedicine and contacting biological fluids. Commonly, "grafting-to" (GT) and "grafting-from" (GF) methods are used to attain the polymer brush architecture on various surfaces. This study investigates the grafting density and antifouling effectiveness of poly[N-(2-hydroxypropyl) methacrylamide] (poly(HPMA)) brushes synthesized via reversible addition-fragmentation chain-transfer (RAFT) polymerization, employing both GT and GF techniques. To determine the molar masses of solution-born and GF poly(HPMA), size exclusion chromatography (SEC) equipped with multiple angle laser light scattering (MALS) and atomic force microscopy (AFM)-based single-molecule force spectroscopy (SMFS) were combined and thoroughly used. Furthermore, the impact of solvent effects on polymer brush propagation kinetics during the concomitant surface-initiated- (SI-) RAFT process between surface and solution was investigated. Experimental findings revealed discrepancies between GF and solution-born poly(HPMA) chains. Notably, solvent composition influenced both the propagation rate and the inferred grafting density of surface-grafted poly(HPMA) due to variations in...
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Preparation and implementation of construction and technical survey of prestressed bridge structure
Kubová, Klaudie ; Sedláček, Ondřej (referee) ; Anton, Ondřej (advisor)
The bachelor's thesis deals with the technical survey of the load-bearing structure of the left part of prestressed motorway bridge D2-058..2. The bridge is located on the border between the Czechia and Slovakia, and it was built in 1980. The work is focused on locating the prestressing reinforcement of prefabricated beams and determining its condition. The theoretical part describes the principle of static action of reinforced and prestressed concrete, categorization of technical surveys of structures and diagnostic methods. The work also presents specific diagnostic methods for determining the position and condition of prestressing reinforcement. In the practical part, the work deals with the analysis of beams by means of ground penetrating radar and probes for analysis of the condition of reinforcement. The outcome of the work is a study of the deviations of the position of prestressing cables from the original project documentation and determination of their condition in terms of corrosion degree and grouting.
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Information Fusion for Classification of Network Devices
Sedláček, Ondřej ; Tisovčík, Peter (referee) ; Žádník, Martin (advisor)
This work is focused on solving information fusion when dealing with multiple data sources in computer network monitoring. A solution built on the concept of classification rules configured by experts is presented. Configuration is simplified using a designated configuration language interpreted by the solution. The classification rules enable coverage of diverse types of data. The result is given as a label from specified taxonomy. Using a taxonomy maintains the different levels of detail between the data sources, even in the output label. The solution also uses the Dempster-Schafer theory for merging labels from different sources into a single output label. Results of experiments show that information fusion in this context does increase the accuracy of device classification. A process of rule optimization was developed based on testing and experiments with a dataset from a real network. The accuracy was increased by 19 % compared to the original solution using this process.
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Study of sewerage in village Nasavrky
Sedláček, Ondřej ; Beránek, Josef (referee) ; Raclavský, Jaroslav (advisor)
The author of master's thesis submit study of alternative solution sewerage in Nasarvky. He made passportization and he design gravity, pressure and vacuum sewerage for the area of interest. He deals with the problems about storm sewerage and he design suitable solution. The study content issues technical and economic variants valorization. Object of study is recommendation the best alternative sewerage in Nasavrky.
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SiOx based barrier coatings
Sedláček, Ondřej ; Dzik, Petr (referee) ; Přikryl, Radek (advisor)
The theme of this thesis is based on the preparation and characterization thin films prepared by methods like a Physical Vapor Deposition, Plasma Assisted Vapor Deposition and Plasma Enhanced Chemical Vapor Deposition. The elementary materials for the preparation of these layers are silicon monooxide powder, melamine and hexamethyldisiloxane. These layers have been prepared with regards to their usage like a barrier coatings with emphasis on poisonous organic substances resistance.. We made a characterization of these films. This characterization is consist of researching of their physical properties (the ability to resist permeation of certain organic compounds), and their chemical composition too. We used to some specific method for these characteristics, for example: FTIR, OTR, ellipsometry, SEM and measuring of the permeation of selected industrial pollutants resistance.
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