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Igbo national consciousnes
Štěpánková, Hana ; Skupnik, Jaroslav (advisor) ; Chlup, Radek (referee)
Before the direct contact with Europe, the area of present-day south-eastern Nigeria was inhabited by a dispersed population limited to only village or local consciousness but in 1967 representatives of this region declared the independent state of Biafra with the intention to separate from Nigeria which indicates strong collective consciousness. The bearers of this consciousness consider themselves to be Igbo and the collectivity has features of a nation. Therefore it is the Igbo national consciousness I deal with in this thesis. In the theoretical introduction I situate a nation within the sphere of ideas. The historiographic part of the thesis examines how the Igbo nation came into existence. It deals with traditional culture, trade, missionary activity, education, colonial administration, migration, decolonization and politics in independent Nigeria. The second, semiologic part is based on my research among the Igbos in Prague and focuses on the contemporary means for the inter-subjective maintenance of their national consciousness. I try to explain it using a concept of national symbols which can be understood as narratives supporting the idea of continuity, strengthening of borders and assuring the internal homogeneity as distinguished from the external differences.
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Návrh a testování způsobů zvýšení účinnosti transfekce živočišných buněk
Štěpánková, Hana
Master’s thesis deals with the design and testing of methods of increasing the transfection efficiency in mammalian cells. In this work a polyethylenimine (PEI) transfection method was used. The transfection efficiency was tested using MDA-MB-231 breast cancer cell line and pcDNA3.1-GFP-hMT-TOPO vector. We focused on optimization of PEI (1-6 µg) and plasmid DNA (1-3 µg) concentration, transfection time (0-48 h), number of cells per 9 cm2 (100,000-2 million) and medium composition. A complex containing linear penetration peptides (CPPs) KALA and GALA was assembled. Concentration of CPPs (7,5-45 µg) was optimized and a zeta potential and a size of the complexes were investigated. Due to the formation of large aggregates (over 1200 nm), modification with polyethyleneglycol (PEGylation) of PEI was performed. With the resulting complexes (~15 nm), transfection was performed. Transfection and apoptosis induction rates were compared between PEI and PEGylated PEI and as the best was chosen conjugate of PEGylated PEI (3 µg) with 45 µg of GALA and 3 µg pDNA with efficiency of 75%.
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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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Nuclear magnetic resonance in magnetic systems
Křišťan, Petr ; Štěpánková, Helena (advisor) ; Mašláň, Miroslav (referee) ; Schneeweiss, Oldřich (referee)
Title: NMR in magnetic systems Author: Petr Křišťan Department: Department of Low Temperature Physics Supervisor: prof. RNDr. Helena Štěpánková, CSc. Abstract: Magnetically ordered iron oxides, namely magnetite, maghemite, hexagonal ferrite M or system Fe-B, with nano or submicron dimensions of particles are the main subject of study of the presented thesis. The materials were investigated mainly by 57 Fe nuclear magnetic resonance (NMR). The results were thoroughly analyzed and compared with the results obtained by other methods (Mössbauer spectroscopy, ZFC/FC magnetic measurement, X-ray diffraction or TEM). In case of the maghemite nanoparticles a regular distribution of vacancies in octahedral positions was verified by the help of NMR in external magnetic fields and at various temperatures. The experi- mental results were also compared with ab-initio calculations. In thin layers of barium M type hexaferrite, effects of reduced particle size on 57 Fe NMR spectra were observed. The NMR methods were also successfully applied to investigation of system FeMoCuB of amorphous and nanocrystalline ribbons, where 57 Fe NMR was able to resolve formation of different phases in depen- dence on the process of preparation. Due to different NMR excitation condi- tions of signal from strontium M type hexaferrite and maghemite,...
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Faktory ovlivňující délku březosti skotu
Štěpánková, Hana
The bachelor thesis is focused on the analysis of factors that has an impact on the length of gestation period of Holstein cattle. The duration of pregnancy was influenced by the year and month of conception. Other important factors were the sex of calves, parity, twins and dead born calves. The results showed that the duration of pregnancy is influenced by many factors. Some of them are little known. The knowledge of reproduction is very important for cattle industry. In conclusion, some other research is necessary to deeper understand this complex problem.
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The impact of working memory training on fluid intelligence in young-old adults
Štěpánková, Hana ; Niederlová, Markéta (advisor) ; Holmerová, Iva (referee) ; Smolík, Filip (referee)
Description and explanation of a natural decline of cognitive functions during ontogenetic aging laid in a century of its history grounds for various experiments trying to find wals to slow down or revoke theis process of decline. One of the cognitive domains that has been gaining ever stronger attention among neuroscientists is working memory, which is interconnected with other functions, especially with attention, executive function and fluid intelligence. So far, there has not been reached a consensus regarding a model of working memory. Nevertheless, there are many efforts to describe it, to explain its role within cognitive processes, and to enhance performance. They resulted in various complex and also specialized interventions that are used also in studies focused on older persons. This study adds to the body of literature on transfer effects of working memory training in young-old persons (age 65-75 years; N=65). It is a randomized controlled study with 2 intervened and 1 passive control groups. The goal was to find about an effect of different numbers of training lessons (10 or 20 in 5 weeks) with a computer-based adaptive visually presented verbal n-back, on latent variables of working memory and fluid intelligence. The results showed an ability of older people to significantly improve their...
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