|
|
Statistics of directional data with an application in crystallography
Karafiátová, Iva ; Šedivý, Ondřej (advisor) ; Hlubinka, Daniel (referee)
The main purpose of this thesis is to derive methods used to estimate the mean orientation of a grain in polycrystalline material. The estimation is highly impor- tant in crystallography. However, it is often expressed by only one representative value regardless of its variability within the grain. In this thesis we present the basic concepts of crystallography, including the principle of the Electron Backs- catter Diffraction, which is used to explore the microstructure of a polycrystalline materials. Subsequently, we present six of the most commonly used descriptors of three-dimensional orientation of a crystal lattice. This overview is completed by the summary of the particular relationships between those descriptors. In the practical part of this thesis we apply derived methods on real data within the scope of research of microstructure of an aluminum alloy. 1
|
|
|
Bioinformatic analysis of protein/DNA interactions
Božíková, Paulína ; Schneider, Bohdan (advisor) ; Hašek, Jindřich (referee)
In this thesis, we focused on local structural features of the DNA backbone in protein-complexed DNA and non-complexed (naked) DNA, and its dependence on types of a base pairing in DNA, and on the base sequence. To reach this goal we analyzed about 1,400 crystal structures of DNA in complexes with proteins and more than 400 crystal structures of naked DNA. DNA local conformations were structurally classified into 38 dinucleotide conformers ntCs, which were described previously (Svozil et al. Nucleic Acids Res. 2008). The ntC were further clustered into 16 structural alphabet classes ntA to reduce the number of analyzed variables. We assembled base-paired dinucleotides from double helical DNA structures accord- ing to their assigned structural alphabet classes into so called Association matrices. Three basic Association matrices were analyzed; two compare ntA/ntA associations between dinucleotides forming only Watson-Crick base pairs in protein/DNA com- plexes and in naked DNA, respectively; the third one ntA/ntA associations between dinucleotides base-paired also by non-Watson-Crick pairs. We also analyzed As- sociation matrices of dinucleotides as a function of their sequences. The analyzes revealed differences in structural behavior of various ntA and their dependence on dinucleotide sequences.
|
|
| |
|
|
Analysis of x-ray diphractograms of organic crystalline solids
Stejkora, Jakub ; Žídek, Jan (referee) ; Salyk, Ota (advisor)
Derivates of diketopyrrolopyrrole are colored pigments with potential use in field of organic semiconductor structures. Their electrical attributes such as conductivity, photocon¬¬ductivity and electroluminescence relate to their crystal structures that determine charge transport path through the compound. For crystallographic structure determination from RTG diffractometry it is needed to grow a measurable single crystal. Growing crystals of derivates of diketopyrrolopyrrols is very difficult due to their poor solubility in all solvents. Several relatively suitable – perhaps even measurable – samples were obtained throughout the testing of series of methods. One of these samples was measured with RTG diffractometry and on the ground of this measurement it was possible to find and solve the crystallographic structure.
|
guest ::
