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Selective growth of GaN on SiN
Hulva, Jan ; Kolíbal, Miroslav (referee) ; Mach, Jindřich (advisor)
This bachelor's thesis deals with the selective growth of gallium and gallium nitride on silicon nitride (SiN) substrates. Thin silicon nitride layers are deposited on silicon substrates. Oxide structures are prepared by the local anodic oxidation method (LAO) on SiN substrates. These surfaces can be editionally modified by etching in hydrofluoric acid. Modified substrates are used for the deposition of gallium or gallium nitride under ultra-high vacuum conditions. Consequently, ordering of deposited material was studied in areas modified by LAO. Chemical state of layers is studied by X-ray photoelectron spectroscopy. Morphology of surfaces is measured by the atomic force microscope (AFM).
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Phosphinoferrocene amides and hydrazides
Solařová, Hana ; Štěpnička, Petr (advisor) ; Kubíček, Vojtěch (referee)
Title: Phosphinoferrocene amides and hydrazides Author: Hana Solařová Department: Department of Inorganic Chemistry Supervisor: doc. RNDr. Petr Štěpnička, Ph.D. Abstract: While studying functionalized phosphinoferrocene ligands, we recently turned to phosphinoferrocene carboxamides. These donors already proved to be versatile ligands for coordination chemistry and catalysis. This led us to synthesize and study the archetypal representative, 1'-(diphenylphosphino)-1-carbamoylferrocene (5), and the corresponding hydrazide 6. PPh2 COOH Fe Hdpf PPh2 CONH2 Fe 5 PPh2 CONHNH2 Fe 6 This work describes the preparation of primary amide 5 and hydrazide 6 from 1'- (diphenylphosphino)-1-ferrocenecarboxylic acid (Hdpf) via the corresponding acylbenzo- triazole derivative. The hydrazide was alternatively obtained from Hdpf methylester and hydrazine hydrate. Both newly synthesized compounds were characterized by spectroscopic methods (NMR, IR, and MS) and elemental analysis, and their crystal structures were determined by single-crystal X-ray crystallography. The amide was further utilized in the preparation of several palladium complexes, which were characterized in a similar manner including X-ray crystallography. One palladium complex was obtained also from the hydrazide. However, the hydrazide was used mainly as a...
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Determination of acidic groups in humic substances.
Kabeláčová, Kateřina ; Sedláček, Petr (referee) ; Janeček, Jiří (advisor)
Within this bachelor thesis we compared three method to determine the acidity of humic substances. We employed the baryta-method (which determines the total acidity), the Ca-acetate method (determines the content of carboxylic groups only) and the technique of Ray von Wandruszka. This method should provide the content of groups dissociable at pH>12. We used four different samples of humic acids isolated from two sources (lignite and peat). While the differences between results of baryta and Ca-acetate methods were expected and can be easily explained, the values of acidity obtained by the von Wandruszka method represent roughly one half of the results of Ca-acetate method and almost only ten percent of the baryta results. In the cases of baryta as well as von Wandruszka methods we observed a dependency of the results on the time-length of the analysis. In the theoretical part the characterisation, divided, creation, structure and properties of humic substances are summarized. In the end of theoretical part are described using method for analysis of humic acids.
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Monitoring of changes of grape juice chemical parameters during the process of fermentation
Bídová, Veronika ; Vespalcová, Milena (referee) ; Vránová, Dana (advisor)
This bachelor work deals with chemical changes of the wine must during the fermentation process. In the introductory theoretical part is mentioned the history of wine and characteristic of wine. Further work is devoted to the chemical composition of must and wine producing technology. It describes the grape harvest, pressing, adjustment of the must with chemicals, fermentation and wine training. The theoretical part describes the basic analytical techniques for monitoring the qualitative parameters of wine. In the experimental section are summarized the results of the titratable acids, total polyphenols and the pH of the must from integrated and organic vineyards. The results are evaluated critically.
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Determination of phosphates in waters and characterization of their negtive effects on water ecosystem
Novotný, Radek ; Komendová, Renata (referee) ; Sommer, Lumír (advisor)
This bachelor thesis is focused on the negative effects of phosphates in natural waters and their methods of determination. The first part is characterized by a negative impact on natural water and there are characterized the problems associated with eutrophication, development of cyanobacteria and algae and the resulting potential health risks. The second section describes the methods by which phosphates can be determined. The work highlights the particular spectrophotometric methods such as molybdophosphoric acid, vanadomolybdophosphoric acid, wolframophosphoric acid, phosphomolybdenum blue and methods with some basic dyes such as rhodamine B, rhodamine 6G, malachite green and crystal violet. There are also mentioned methods, which are used less frequently, but they are relatively sensitive, such as AAS, AES, LC-ICP-MS and next such as chromatographic, electrochemical and enzymatic methods. Finally, work mentions the possibility of using automatic techniques such as FIA or CFA, which are suitable for routine and frequent determination, often using the spectrophotometric methods, but not only these.
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Qulity of lipids in foods
Křivohlavá, Renata ; Doležal, Marek (advisor) ; Tvrzická, Eva (referee)
The title of the work is "Quality of lipids in food". The work is divided into two parts. The first is theoretical, the other is experimental. The theoretical part is divided into two chapters. The first section describes general chemical composition and properties of lipids. This point is further divided into four sections, which are specifically focused on different groups of lipids. The second theoretical point of attention is focused on the importance of fat in the diet, the synthesis of fatty acids, lipid digestion and issues related to absorbancy and lipid transport. This section also contains a passage which refers to further dietary recommendations, among which highlights the question of the proper quantity and quality of fat contained in food. There are not omitted principles of proper use and storage of fat. The last section of this section deals with dietary supplements and functional foods from which the positive effect on human health is expected. The experimental part is based on chemical analysis of twenty samples of dietary supplements containing n-3 fatty acids. These fatty acids play a vital role in the prevention and treatment of many diseases, especially myocardial infarction or ischemic heart disease. In the screening of these products, attention was focused on the content of...
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Isosters of transkarbams, synthesis, properties and biological activity
Holas, Tomáš ; Hrabálek, Alexandr (advisor) ; Sedlák, Miloš (referee) ; Beneš, Luděk (referee)
1. SUMMARY The major aim of this dissertation was to synthesize and test isosteric analogs of T12. On the whole, 76 new compounds were prepared which have not previously been published. 28 compounds were tested as the transdermal permeation enhancers. Structure of these synthesized compounds was confirmed by FTIR, 1 H NMR and 13 C NMR analysis. Purity of the carbamate salts was verified by CHN analysis. With respect to the results, financial and time demandingness, permeation-enhancing activity was measured only on selected compounds. More than 400 permeation experiments were performed, more than 3000 HPLC chromatograms were analysed. To sum up, the permeation studies have shown that there is the relationship between structure and action of the studied compounds in the middle-lipophilic donor medium. Permeation-enhancing activity from the 60% propyleneglycol donor medium is in the following order: ester carbonate ketone ≥ amide = carbamate = alkane. Furthermore, there have been found another arguments confirming proposed mechanism of action of T12 - CO2 release in stratum corneum.
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Synthesis of human ω-O-acylceramides and evaluation of their effects on barrier properties of skin lipid membranes
Opálka, Lukáš ; Vávrová, Kateřina (advisor) ; Hampl, František (referee) ; Kučerka, Norbert (referee)
Charles University in Prague, Faculty of Pharmacy in Hradec Králové Department of Inorganic and Organic chemistry Candidate: Mgr. Lukáš Opálka Supervisor: doc. PharmDr. Kateřina Vávrová, Ph.D. Title of doctoral thesis: Synthesis of human ω-O-acylceramides and evaluation of their effects on barrier properties of skin lipid membranes The main objective of this work was to synthesize and study human acylceramides (acylCer, ceramides of the EO type) with the focus on the relationships between the acylCer concentration , structure of their polar head, their ability to form lamellar phases and permeability of model lipid membranes. Another objective was to synthesize ceramide-1-phosphates for the study of their signaling role in skin barrier and an analogue of ganglioside GM1 with shorter acyl chain as a standard for analysis of these lipids. Ceramides (Cer) belong to the family of sphingolipids. They are the central molecules in sphingolipid metabolism, they participate on cell regulatory processes and the formation of human skin lipid barrier. The main skin barrier is situated in the stratum corneum (SC), which is the uppermost layer of skin. The purpose of SC is to maintain homeostasis of the inner environment and to prevent the penetration of exogenous substances, allergens and bacteria to the...
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Human microsomal glutathione s-transferase
Hrnčiarik, Karel ; Wsól, Vladimír (advisor) ; Kvasničková, Eva (referee)
The microsomal glutathione S-transferases (GST, EC 2.5.1.18) constitute a group of phase II detoxification enzymes present in eukaryotic cells and prokaryotic organisms. They play significant roles in defense against carcinogenic, toxic, and pharmacologically active electrophilic compounds. The microsomal glutathione S-transferase is a homotrimeric, membrane-bound enzyme, that catalyzes conjugation of electrophilic compounds with glutathione and reduction of lipid hydroperoxides. Peroxidase activity may be of importance for protection against lipid peroxidation under conditions of oxidative stress. A number of biochemical approaches have been used to study the properties of MGST, including enzymatic activity, sub-cellular distribution, substrate specificity, and proteins structure. MGST is considered a member of the MAPEG (membrane- associated proteins in eicosanoid and glutathione metabolism) superfamily of structurally and phylogeneticaily related enzymes, including MGST 1, MGST 2, MGST3, microsomal Ya-GST, MGST 1 Like 1, 5-lipoxygenase activating protein, and leukotriene C4 synthase. Enzymes in this superfamily are involved in detoxification, protection from oxidative stress, and synthesis of prostaglandin E and cysteinyl leukotrienes. On the basis of understanding funcitons MGST is possible...
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Synthesis of novel cardioprotective iron chelators
Hrušková, Kateřina ; Roh, Jaroslav (referee) ; Vávrová, Kateřina (advisor)
Oxidative stress participates in patophysiology of many serious cardiovascular diseases. Free intracellular iron occurs as a catalyst of Haber-Weiss and Fenton reaction between superoxides and peroxides increasing the formation of highly toxic hydroxyl radicals, which cause cell damage. Iron chelators diminish the pool of free iron and thus become perspective agents in therapy of various diseases, e.g. anthracycline-induced cardiotoxicity. Aroylhydrazones group, such as salicylaldehyde-isonicotinoylhydrazone (SIH), appear to be highly efficient chelators. Unfortunately, pharmacokinetic studies focused on these compounds revealed their low stability in plasma. Therefore, I synthesised a series of SIH analogs in order to increase their stability together with preserving the ability to chelate free intracellular iron and to define their structure-activity relationships. A basic hypothesis in design of the novel chelators was using substituted ketone instead of aldehyde, leading potentially to an enhanced stability of hydrazone bond. SIH Two different methods were used during the reactions, a conventional heating in an oil bath and heating in a microwave reactor. The latter caused a significant shortening of the reaction time. In vitro studies of novel compounds showed their higher stability in plasma,...
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