The goal of this Master thesis is to demonstrate Witteńs mechanism in selected extensions of the Standard model based on the Pati-Salam gauge group. The purpose of this mechanism is to obtain an extremely large Majorana mass term for right-handed neutrinos at the two-loop level and consequently light physical masses of neutrinos using the type I see-saw mechanism. The existence of corresponding Feynman diagrams without any interactions of vector bosons is presented. While it is impossible to construct this type of corrections in minimal SO(10) or SU(5)xU(1) model in Pati-Salam model they may be even dominant. Subsequently, implications of possible partial gauge coupling unification or even embedding of the Pati-Salam group into a gauge group of "Great Unified Theory" are considered. At the end the possibility of unacceptably fast proton decay is inspected. The discussed models are concluded to be potentially realistic but only at the cost of predictivity, since completely unknown Yukawa couplings appear in numerous key relations. 1

Hyaluronan is a chemical, which can be qualified as essential for vertebrates. It is a part of the extracellular matrix in most of tissues and also a major component of some other tissues. Besides of the mechanical functions this compound is important for many biological processes such as growth of tumor cells. The objective of this thesis was development of carrier systems containing native hyaluronan and hydrophobic drugs. For purposes of this work fluorescence probes (pyrene, prodan, perylene, DPH, mereocynine 540) instead of drugs were used. By using further mentioned sophisticated methods the properties of these systems were studied. The systems were prepared by freeze-drying. The effect of freeze-drying on support of interactions was observed by fluorescence spectrometry (steady-state and time-resolved). The stability of freeze-dried systems was determined by zeta potential, which was measured by electrophoretic light scattering. Cakes obtained by freeze-drying were analyzed by several methods. First one was effluence gas chromatography connected with FT-IR spectrometry. In this method the present of tertiary butyl alcohol in product was observed. The cakes were also analyzed by scanning electron microscopy, which can provide the information about the surface and elemental constitution of the material. The results of this work can shed light on the area of developing of drugs with targeted distribution of active compound.

Perfect simulations are methods, which convert suitable Markov chain Monte Carlo (MCMC) algorithms into algorithms which return exact draws from the target distribution, instead of approximations based on long-time convergence to equilibrium. In recent years a lot of various perfect simulation algorithms were developed. This work provides a unified exposition of some perfect simulation algorithms with applications to spatial point processes, especially to the Strauss process and area-interaction process. Described algorithms and their properties are compared theoretically and also by a simulation study.

Humic acids and humates are principal components of humic substances major organic constituents of soil, peat, coal and water around the world. I was involved in research into molecular dynamics simulations of interactions of quartz surfaces with aqueous solutions of ions and small organic molecules representing basic building blocks of larger biomolecules and functional groups of organic matter. We studied interactions of molecules with surfaces for a set of surface charge densities corresponding to the experimentally or environmentally relevant ranges of pH values employing molecular mechanics, molecular dynamics and ab initio techniques. Simulated quartz surfaces covered the range of surface charge densities 0.00, -0.03, -0.06 and -0.12 C-m-2, approximately corresponding to pH values 4.5, 7.5, 9.5 and 11. As model molecules, benzoic acid, phenol, o-salicylic acid and their conjugated bases were chosen. My task was to prepare topologies and parametric models of selected organic matter basic building blocks organic molecules. I focused on studying interactions of these molecules in an aqueous environment with mineral surface quartz. The aim was to process simulation results and analyse conformations of the adsorption complexes and their thermodynamic properties such as interaction energies, free energies and adsorption geometries.

The thesis is focused on the communication inclusion and exclusivity of Czech journalist on Twitter and how they use conventions of this platform to connect with other users. Through the description of current communication layers and functions of Twitter this thesis depicts how it became one of main sources of news and how it pushed journalists to reinterpret their traditional roles in the society. It also describe how digital humanities and digital trace data gathered from social media can be used as means of analysis of social interactions of its users. The practical part presents a cluster analysis based on Twitter data of 457 Czech journalists that shows how is Twitter used to communicate within and outside the Czech media system.