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The Study of Dynamic Behaviour and Interactions During the Temperature-Induced Phase Separation in Polymer Solutions
Kouřilová, Hana ; Hanyková, Lenka (advisor) ; Štěpánková, Helena (referee) ; Dušková - Smrčková, Miroslava (referee)
Title: The Study of Dynamic Behaviour and Interactions During the Tempera- ture-Induced Phase Separation in Polymer Solutions Author: Hana Kouřilová Department / Institute: Charles University in Prague, Faculty of Mathemat- ics and Physics, Department of Macromolecular Physics Supervisor of the doctoral thesis: doc. RNDr. Lenka Hanyková, Dr. Abstract: 1 H and 13 C high-resolution NMR spectroscopies were used for the phase separation investigation in three types of polymer solutions: i) poly(N -isopropylmethacrylamide)/D2O/ethanol with or without negatively charged comonomer sodium methacrylate, ii) random copolymers poly(N -isopro- pylmethacrylamide-co-acrylamide) in D2O, D2O/ethanol and D2O/acetone and iii) D2O solutions of polymer mixtures poly(N -isopropylmethacrylamide)/poly(N - vinylcaprolactam). For i) cononsolvency effect and influence of temperature on the phase separation was studied. Differences between mesoglobules formed as a consequence of cononsolvency effect and of temperature were found. While inside the cononsolvency-induced mesoglobules no bound ethanol molecules were detect- ed, in the mesoglobules formed by the effect of temperature ethanol molecules were present. The charge introduced into the polymer chains strenghtens polymer- solvent interactions. For ii) mesoglobules were found to be...
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Study of Cobaltites and Manganites by NMR and EXAFS
Procházka, Vít ; Štěpánková, Helena (advisor) ; Novák, Pavel (referee) ; Figiel, Henryk (referee)
This Thesis is devoted to a study of physical properties of manganites and cobaltites with perovskite structure. Combination of macroscopic (magnetization measurements and X-ray powder diraction) and microscopic (NMR and EXAFS) methods was applied in order to get a complex and detailed view on the charge and magnetic ordering of transition metals ions in the LaMn1xCoxO3 solid solutions. The Thesis presents new results which were published in international journals. The main result is the determination of details of Mn and Co local environments and the spin arrangement of their individual oxidation states in the ferrimagnetic structure of the compounds studied.
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MR spectroscopy in patients with diabetes mellitus
Šedivý, Petr ; Štěpánková, Helena (advisor) ; Roztočil, Karel (referee)
This thesis deals with in vivo MR spectroscopy. Measurements in this thesis were performed on whole-body MR tomograph at the Institute for Clinical and Experimental Medicine in Prague. The objective of the thesis was to study differences in the biochemical processes and energy metabolism in the muscle tissue under physical workload between the groups of healthy subjects and patients with type 1 diabetes mellitus (DM1). We used phosphorous spectroscopy in combination with ergometer. The thesis is divided into five chapters. The first chapter describes theoretical introduction to in vivo 1 H and 31 P MR spectroscopy and muscle metabolism, the second chapter deals with the description of the experimental equipment and measurement, results of the thesis are reported in the third chapter and the fourth chapter is a discussion of results. Main result of this work is summarized in conclusion; we found differences between the metabolism of patients with DM1 and healthy volunteers.
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Spin-lattice and spin-spin NMR relaxation of 1H nuclei in deuterated etanol and butanol doped by TEMPO radical
Matoušek, Jan ; Englich, Jiří (advisor) ; Štěpánková, Helena (referee)
The thesis deals with study of deuterated ethanol and butanol (ethyl-D5 alcohol, butyl-D9 alcohol) with a small amount (0 to 1.5% weight) of dissolved stable free radical TEMPO by methods of NMR. This system is used in polarized targets for high energy experiments. The linear dependence of spin-lattice and spin-spin relaxation rate of hydrogen nuclei from OH group of an alcohol on the radical concentration and dependence of the relaxation rates decreasing with temperature (in range from 250 to 298K) were obtained. The T1/T2 ratio from 1.3 to 2.0 was calculated. This was interpreted as an effect of a contact interaction via hydrogen bond between alcohol and radical molecules. The linear dependence of the resonance frequency of hydrogen nuclei from OH group on the radical concentration was obtained. The slope of the dependence line didn't change with temperature. Using this dependence the hyperfine constant of the interaction between hydrogen nucleus and the free electron of the radical was estimated approximately 8·10-28 J. It was found out that the lifetime of the hydrogen bonds between alcohol and radical molecules are about 10-11 s or longer.
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Theory of cleavages and development of Party System. Comparison of Czech Republic, Slovakia and Poland
Štěpánková, Helena ; Novák, Miroslav (advisor) ; Mlejnek, Josef (referee)
This diploma thesis deals with a development of the socioeconomic cleavage in the party systems of the Czech Republic, Slovakia and Poland in 2006 - 2012. At the beginning the theory of cleavages by S. Rokkan and S. M. Lipset and the enlargement to post-communist countries of Klaus von Beyme, are presented. There are also mentioned concepts of other authors. The thesis tries to answer a few questions. Firstly, what form did this line have in the monitored period (transformation line vs. classical socioeconomic line). Secondly, how big was an impact on the political right-left orientation of the political parties, and thirdly, how significant was this line for the party-political system of selected countries in this period. There is also a brief development of the party system after 1989 as well as the ideological profiles of parliamentary parties given in each chapter focused on particular country. One part of it deals also with the economic and social climate in the monitored period. Then the work is based mainly on the analysis of party's agenda, with an emphasis on the socioeconomic line.
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Hyperfine interactions and electronic structure of magnetite
Řezníček, Richard ; Štěpánková, Helena (advisor) ; Máca, František (referee) ; Schneeweiss, Oldřich (referee)
The present work focuses on analyses of the experimental 57 Fe nuclear magnetic resonance data and the results of ab initio calculations in order to achieve deeper insight into the hyperfine and electronic structure of magnetite both below and above the Verwey phase transition. Parameters of hyperfine interactions and electronic structure data of the Cc phase of magnetite were extracted from the results of ab initio calculations based on the recently reported crystal structure. Published experimental dependences of the 57 Fe nuclear magnetic resonance frequencies on the external magnetic field direction were quantitatively reanalyzed, yielding hyperfine anisotropy data, which were compared to the analogous hyperfine field parameters from the ab initio calculations. The findings were interpreted in the context of up-to-date charge ordering models for magnetite. Attention was also paid to the impact of various cationic substitutions and defects on the electronic structure and hyperfine interactions in magnetite manifested in the 57 Fe nuclear magnetic resonance spectra: below the Verwey transition, signal intensity shifts in the spectra were analyzed; above the Verwey transition, the mean field model was adapted for an analysis of temperature dependence of satellite signal frequencies, while the anomalous...
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NMR Study of Oligonucleotide Structures
Římal, Václav ; Štěpánková, Helena (advisor) ; Spěváček, Jiří (referee) ; Sychrovský, Vladimír (referee)
Title: NMR Study of Oligonucleotide Structures Author: Václav Římal Department: Department of Low-Temperature Physics Supervisor: Prof. RNDr. Helena Štěpánková, CSc., Department of Low- Temperature Physics Abstract: The dynamics of nucleic acids plays a fundamental role in the interactions with proteins. Some processes are governed by changes in DNA stability and flexibility caused by sequence alterations or chemical modifications without substantial structural impact. We employed line-shape analysis of variable-temperature 1H NMR spectra to deeply investigate the melting transition of DNA structures. We observed a significant influence of the sequence beyond the nearest neighbours on chemical shifts and thermodynamics of the double helix. The CpG motif is especially sensitive to its distant surroundings and for a particular oligonucleotide it was even found to undergo an unexpected local conformational transition. A strong cooperativity in the duplex dis- ruption was witnessed by both the equilibrium and kinetic aspects as well as by distant effects of cytosine methylation. We propose a two-state melt- ing scheme also for a fragment of a transcription element proved here to fold as a hairpin with a six-membered loop. In addition, we describe the properties of self-assemblies of riboguanosine and...
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