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Transition metal ion complexes as potential 19F MRI contrast agents
Dobrovolná, Tereza ; Kotek, Jan (advisor) ; Blahut, Jan (referee)
Fluorinated coordination compounds having short nuclear spin relaxation times due to the presence of paramagnetic metal ions close to 19 F nuclei are suitable/potential contrast agents in 19 F MRI. This thesis deals with the preparation of a ligand based on 1,4,7-triazacyclononane (TACN) with pendant arms containing fluorine atoms. The coordination properties to transition metal ions were studied and prepared complexes were characterised. Measured values of longitudinal relaxation times of 19 F NMR signal indicate that the chosen concept is promising for further use in 19 F MRI, especially for the Co(II) complex. Keywords: 19 F MRI, contrast agent, trifluoroethyl phosphinic acid, TACN, paramagnetic ion, relaxation time, effective magnetic moment
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Fluorinated macrocycles for 19F MRI
Šmelko, Andrej ; Hermann, Petr (advisor) ; Blahut, Jan (referee)
19 F MRI contrast agents are relatively new, developing field of medical and chemical sciences. In this Theses, based on previous results in this area, new type of Ni2+ complex with possible 19 F MRI applications was synthesized and characterized by relaxometric measurements.
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Experimental investigation of shear strength of soils from the Dobkovičky landslide area and development of correlations between soil strength and their physical properties
Roháč, Jakub ; Mašín, David (advisor) ; Blahůt, Jan (referee) ; Hrubešová, Eva (referee)
Critical and residual states are key soil conditions relevant to slope stability. Evaluating the available shear strength in relation to these conditions is crucial for reliable stability analyses. The best way to determine the strength parameters is through properly selected laboratory tests of soil mechanics. However, in specific cases, these parameters can be estimated based on other material properties of soils. The work clarifies the applicability of various correlation equations from the literature and proposes new relationships, created from laboratory- determined results of strength and index parameters of soils from the Bohemian Central Mountains. It shows how different equations or different material properties of soils can predict the required value of strength. The work also describes how the residual strength of soils and its estimation can be affected. This is mainly caused by the clay fraction proportion and by the shear rate used in its laboratory determination. The results are applied to a specific geotechnical problem - to estimate the critical state and the residual friction angle of soils from the selected study area of the D8 motorway, which is well known thanks to the stability problems. Last but not least, various errors and misunderstandings are discussed, which are often...
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Dynamics of paramagnetic complexes observed by Nuclear Magnetic Resonance
Blahut, Jan
In this Thesis, structure and dynamics of paramagnetic complexes for medical application are studied by Nuclear Magnetic Resonance (NMR). It focuses mainly on development of contrast agents (CA) for Magnetic Resonance Imaging (MRI) which is one of the most effective radiodiagnostic method nowadays. Most of the MRI CAs contains paramagnetic complexes of d- and f-metal ions. The presence of unpaired electron in proximity of NMR active nuclei has two main effects: paramagnetically induced shift and paramagnetically induced relaxa- tion. Both processes can dramatically change the NMR spectrum and often make it unobservable at all. Nevertheless, in many cases, acquisition of such spectra is possible and sometimes even less time-consuming than observation of diamag- netic molecules. Enhanced T1 relaxation allows faster pulse sequence repetition and increased chemical shift dispersion may lead to resolution of originally over- lapped signals. Moreover, the analysis of paramagnetic effects can provide useful information about the structure and dynamics of the studied system. Theoretical background of these effects is described in the Introduction of the Thesis. In the first part of Discussion in the Thesis, a new class of contrast agents for 19F-MRI based on nickel(II) and cobalt(II/III) ions is introduced...
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Intermolecular Hydrogen Bonds Studied by NMR Spectroscopy
Osifová, Zuzana ; Dračínský, Martin (advisor) ; Blahut, Jan (referee)
N-methylation of nucleic acids is one of the most important epigenetic mechanisms in organisms and viruses and it is observed in connection with physiological or pathological processes in human body. For example, the N- methylation of adenine to give N6 -methyladenine is associated with development of obesity or Alzheimer disease. These systems can be successfully studied by low- temperature NMR spectroscopy because the bond between a purine ring and its substituent has a significant double-bond character and, due to restricted rotation around this bond, two sets of signals are observed in low-temperature NMR spectra. This diploma thesis is focused on research of N-methylated nucleobases' rotamer equilibria and the free-energy changes associated with the hydrogen-bonded base pair formation via simple and straightforward method based on NMR spectroscopy monitoring. We proved that the rotamer equilibria of N-methylated adenine derivatives are dependent on temperature, solvent and bonding partner concentration. We also obtained the geometry of formed intermolecular complexes of N-methylated adenine derivatives with thymine and the free-energy changes associated with their formations via newly developed method based on chemical shift changes dependent on bonding partner concentration. All obtained data...
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Use of rock mass classifications for rock fall susceptibility analysis in the conditions of the Bohemian Massif
Racek, Jonáš ; Blahůt, Jan (advisor) ; Petružálek, Matěj (referee)
This thesis deals with rock mass classification systems. The aim of the thesis is to describe and compare selected systems and evaluate their possible use in the Bohemian Massif for assessing the stability of the rock slopes in relation to their susceptibility to rock falls. A part of the thesis deals with rock falls and basic mechanical characteristics of a rock mass. Further on, the thesis describes selected classification systems, specifically RQD, RSR, RMR, SMR, Q-system, Q-slope, GSI, RSR-PR and QTS. These systems were then used for evaluation of stability of rock slopes on three geologically different locations of the Bohemian Massif. information from measurement in field and processing of measured data was used for assessing for possible use of each classification system.
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3D reconstruction of abandonned ponds using UAV photogrammetry
Stanovský, Tomáš ; Langhammer, Jakub (advisor) ; Blahůt, Jan (referee)
The main focus of the thesis is the reconstruction of 3D models and digital elevation models of five abandoned splash dams in Roklanský brook catchment using UAV photogrammetry methods. The aim of this work is to compare accuracy of the models with available conventional data sources and historical sources. Parallel topic is the research of accuracy of the models created through UAV methods and application of retention potential of small water reservoirs, in headwater areas. The images were taken with a drone-mounted camera. Modelling was done by processing images in software Agisoft PhotoScan through a workflow process, dense point cloud classification and subsequent DEM interpolation. Subsequent delineation of reservoirs retention space, altimetry correction and bathymetric analysis was performed in ArcMap over the interpolated DEM. The results and discussion point to the benefits and limitations of UAV methods, especially to altimetric accuracy of the resulting models relative to conventional DMR5G data and bathymetric characteristics derived from the models. Keywords: UAV; DEM; retention; GIS; model; pond
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Dynamics of paramagnetic complexes observed by Nuclear Magnetic Resonance
Blahut, Jan
In this Thesis, structure and dynamics of paramagnetic complexes for medical application are studied by Nuclear Magnetic Resonance (NMR). It focuses mainly on development of contrast agents (CA) for Magnetic Resonance Imaging (MRI) which is one of the most effective radiodiagnostic method nowadays. Most of the MRI CAs contains paramagnetic complexes of d- and f-metal ions. The presence of unpaired electron in proximity of NMR active nuclei has two main effects: paramagnetically induced shift and paramagnetically induced relaxa- tion. Both processes can dramatically change the NMR spectrum and often make it unobservable at all. Nevertheless, in many cases, acquisition of such spectra is possible and sometimes even less time-consuming than observation of diamag- netic molecules. Enhanced T1 relaxation allows faster pulse sequence repetition and increased chemical shift dispersion may lead to resolution of originally over- lapped signals. Moreover, the analysis of paramagnetic effects can provide useful information about the structure and dynamics of the studied system. Theoretical background of these effects is described in the Introduction of the Thesis. In the first part of Discussion in the Thesis, a new class of contrast agents for 19F-MRI based on nickel(II) and cobalt(II/III) ions is introduced...
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Landslide susceptibility analysis of Czechia
Racek, Ondřej ; Blahůt, Jan (advisor) ; Klimeš, Jan (referee)
In geosciences modelling is rather quickly developing discipline. Statistical modelling of landslide susceptibility is relatively more traditional approach. Nevertheless, more complicated statistical methods are being developed and applied on larger areas. This development is caused especially by increasing computational capacity and software. This diploma thesis summarises existing statistical landslide susceptibility modelling approaches. In the following part, several landslide susceptibility models were created for the area of Czechia. These models were created using logistic regression, naive Bayes and artificial neural network (ANN). Additionally, two more models were created using expert driven approach. All models were made using thirteen conditioning factors, i.e.elevation, slope, engineering geological regions, climatic areas, mean annual precipitation, topographic wetness index (TWI), aspect, orogenetic class, distance from confirmed fault, distance from watercourse, internal relief, land cover and slope shape. Models driven by statistical approach were created using Orange software. Landslide inventories that were used for construction of all models are based on two databases: "Registr svahových nestabilit" and "Registr sesuvů-Geofond". Using validation by SRC, PRC and ROC curves...
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Stability of volcanic islands in relation to giant landslides on the example of El Hierro island, Canary Islands
Olejár, Filip ; Blahůt, Jan (advisor) ; Novotná, Ivona (referee)
Title: Stability of volcanic islands in relation to giant landslides on the example of El Hierro Island, Canary Islands Volcanic islands are known by common occurrence of volcano collapses usually connected with their early stage of formation. When this type of slope deformation occurs, large masses of material, often exceeding hundreds of thousands of cubic meters of rocks, are moving downslope. The development of this kind of movements is firmly linked with the period of volcanic islands growth. Nowadays, slope movements of such dimensions could have catastrophic consequences on inhabited islands. Additionally, in several cases there has been proved emergence of tsunami waves with far-reaching impacts because of these movements. Tsunami hazards have been one of the impulses to examine the probability of these slope movements' developments in today's conditions. In this work, the author tries to prove the impact of seismic activity and rapid changes of ocean water level on the slope stability model of San Andrés giant landslide on the El Hierro Island, Canary Islands archipelago. The geotechnical model parameters were obtained from laboratory analysis of rock material from the island. Then, slope stability models on San Andrés giant landslide were prepared using different combinations of input...
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