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Paleomagnetism and magnetomineralogy of rocks from the Bohemian Massif and Tethyan Realm
Schnabl, Petr ; Pruner, Petr (advisor) ; Hrouda, František (referee) ; Petrovský, Eduard (referee)
Mgr. Petr Schnabl - Dissertation Paleomagnetism and magnetomineralogy of rocks from the Bohemian Massif and Tethyan Realm Abstract The thesis deals with paleomagnetic and rock magnetic properties of Silurian/Devonian and Jurassic/Cretaceous limestones, Paleogene/Neogene basaltic rocks and altered Silurian basalts. The main goal is to determine the history of the Earths' magnetic field from the Silurian to the present. Two lithostratigraphic formations are defined in the Jičín volcanic field on the basis of volcanology, paleomagnetism and radiometric dating. The Trosky Formation (24.6?/18.3 - 15.7 Ma) is composed of several Strombolian-type volcanoes, while the Kozákov Formation (5.2 - 4.6 Ma) is represented by effusive products with a crater vent of a single giant volcano. One Pliocene (4.3-3.3 Ma) and two Pleistocene phases (2.6 -2.1 Ma and 1.8 - 1.1 Ma) of volcanic activity Magnetostratigraphy is a very important tool for the definition of the J/K boundary. The boundary between the Crassicolaria and Calpionella zones is present within geopolarity zone M19n. The boundary between the ammonite zones Jacobi and Durangites also lies close to this point. Paleomagnetic directions of Silurian and Devonian rocks in the Bohemian Massif are very difficult to interpret and have been studied as a challenging problem...
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The use of functional magnetic resonance imaging and MR tractography for neuropsychiatirc studies of cognitive functions
Ibrahim, Ibrahim ; Hájek, Milan (advisor) ; Vymazal, Josef (referee) ; Žižka, Jan (referee)
5. Summary Although conventiona! MR imaging techniques play a crucia! role in the examination of the centra!nervous system (CNS), these techniques can not give any information about functiona! properties of the brain tissue. Besides conventional MRl techniques, however, there are some MR methods enabling evaluation of these functiona! properties. These methods include functiona! magnetic resonance imaging (!MRl), diffusion-weigbted imaging (DWI) or diffusion tensor imaging (DTI), and voxel based morphometry (VBM). fMRI is a method monitoring the activity of the individua! parts of the brain duriog specific tasks and thus c1arifying their functions. fMRI has become the method of choice especia!ly in neurosurgica! procedures plarming, when it is necessary to know the relative location of the pathological lesion and to localize functiona!ly important areas of the cerebra! cortex, and thereby to reduce the risk of damage associated with the neurosurgical operations. DWI and DT[ are very important methods that may be used to assess the severity of cerebra! ischemia and the integrity ofwhite matter tracts based on diffusion properties ofthe brain tissue. Voxel·based morphometry (VBM) is an objective method and fuHy automated whole brain structura! ana! ysis. Neuropathological changes in the brain tissue of...
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Tumor assessment using DCE-MRI image analysis
Šilhán, Jiří ; Zitová, Barbara (advisor) ; Jiřík, Radovan (referee)
This thesis deals with processing of data obtained by DCE-MRI, which uses magnetic resonance to track the propagation of contrast agents in the blo- odstream. Patient is given a contrast agent and then a series of images of the target area is taken. The output is a set of image data and perfusion maps. Work employs segmentation method which uses graph cuts to interactively look for the tumor, and evaluates it according to its shape properties. Study of whole data sets is simplified by image fusion methods.
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Magnetické pole v jádru Galaxie
Hamerský, Jaroslav ; Karas, Vladimír (advisor) ; Kovář, Jiří (referee)
In the present work we study the properties of accretion tori orbiting black hole. Our approach to this problem comes from the solving of general relativistic magnetohydrodynamic equations, which follow from conservation of the energy-momentum tensor, the particle number and from Maxwell's equations. We solve these equations by numerical methods which are described in Chapter 1. The formalism of tori which we consider here is described in Chapter 2. We are interested in tori with constant density of angular momentum and Fishbone-Moncrief tori mainly. We study accretion rates in these tori when the mass of black hole is increased suddenly and so the equilibrium in the torus is corrupted. For tori with constant density of angular momentum we study the influence of the presence of toroidal magnetic field on accretion rates.
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Raman tweezers: principle and applications
Bernatová, Silvie ; Samek, Ota ; Pilát, Zdeněk ; Ježek, Jan ; Kaňka, Jan ; Šiler, Martin ; Zemánek, Pavel
Raman tweezers combines the optical trap for non-contact micromanipulation of micro-objects with Raman spectroscopy for chemical analysis of the sample. This combination presents an efficient tool for concurrent spectroscopic analysis of chemical composition and micromanipulation allowing sorting or probing of mechanical properties of the sample. Raman tweezers were successfully used for example in characterization of biomolecules like DNA, for sorting of cells and investigation of the link between their chemical and mechanical properties.
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The role of sonication of polyethyleneoxide solutions containing magnetic nanoparticles on morphology of nanofibrous mats
Peer, Petra ; Stěnička, M. ; Filip, Petr ; Pizúrová, Naděžda ; Babayan, V.
Properties of the resulting polymer nanofibers are often tailored by sonication technique applied prior or past an electrospinning process. The aim of this contribution is to evaluate morphology of nanofibrous mats formed by poly(ethylene oxide) with distributed magnetic nanoparticles (MNP) (about 20 nm in diameter) in dependence on time of sonication of the used polymer solutions. The solutions were exposed to sonication (intensity 200W, frequency 24 kHz) for 10, 30, and 60 minutes. It was shown that rheological characteristics (viscosity, storage and loss moduli) strongly depend on time of sonication (particularly phase angle) in contrast to electric conductivity and surface tension. For analysis of homogeneous distribution of MNP in polymer solution, the rheological measurements were carried out also in presence of external magnetic field. Magnetorheological efficiency (a relation of corresponding viscosities) was determined for 80, 170, and 255 mT. Consequently, changed rheological characteristics participate significantly in the process of electrospinning and resulting quality of the obtained nanofibrous mats. Qualitative changes were described by\nmeans of scanning electron microscopy (variance of mean diameter of nanofibers), transmission electron microscopy (distribution of MNP within nanofibrous mats). Static magnetic properties were determined by a vibration sample magnetometer. It was shown that even distribution of MNP in the mats can be achieved by mere sonication process without application of external magnetic field during an electrospinning process. However, time of sonication generates a degree of embedding of MNP into individual nanofibers.
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Former convent of Premonstratensian Nuns in Louňovice pod Blaníkem
Smetanová, Marie ; Kubín, Petr (advisor) ; Pátková, Hana (referee)
ANGLICKÁ ANOTACE FORMER KONVENT OF PREMONSTRATENSIAN NUNS IN LOUŇOVICE POD BLANÍKEM Middle Age - Convent - Premonstratensian nuns - Louňovice pod Blaníkem - history Bachelor thesis focuses on history of Premonstratensian nunnery in Louňovice pod Blaníkem within years 1149-1420. The aim of this thesis was to define resemblance of the nunnery from all accessible documents, what property it managed and its organization and role of nunnery in Podblanicko region during pre-feudalism and pre-Husite period.
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The influence of intravenously administeres lactoferrin in early phase of coronnary thrombosis - histopathological analysis
Škrle, Jan ; Semecký, Vladimír (advisor) ; Mladěnka, Přemysl (referee)
Lactoferin (La) is an 80-kDa iron-binding glykoprotein. It shares a high degree of homology at amino acid sequence level and also the three dimensional conformation level with transferin. Afinity of Lf to iron is about 260times higher than that of transferin. Lf is present physiologically in exocrine secretions, eg.: tears, saliva, milk, sinovial fluid, seminal fluid and in the secondary granules of neutophils. The precise function of Lf in organism is considered to be very complex and is still a hot subject of scientific disputation. Lf was documented to act as antimicrobial, antiinflamatory and antitumoral agent. These effects are probably based on its iron chelating properties. Similarly La inhibits hydroxyl radical formation via Fenton reaction due to chelation of free iron. The catecholamine model of myocardial injury, represented by administration of synthetic catecholamine isoprenaline (ISO), posseses many pathophysiological similarities with acute myocardial infarction (AMI). The only possibility for myocardial tissue recovery in AMI represents the reperfusion of ischaemic myocardium. But this process is associated with tissue derangement due to burst of hydroxyl radical catalyzed by free iron (Fenton reaction). Therefore La has been proposed to have potentially positive effects in a catecholamine...
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The role of sonication of PEO solutions with magnetic nanoparticles on morphology of the resulting nanofibrous mats
Peer, Petra ; Stěnička, M. ; Filip, Petr ; Pizúrová, Naděžda ; Babayan, V.
Properties of the resulting polymer nanofibres are often tailored by sonication technique applied prior or past an electrospinning process. The aim of this contribution is to evaluate morphology of nanofibrous mats formed by poly(ethylene oxide) with distributed magnetic nanoparticles (about 20nm in diameter) in dependence on time of sonication of the used polymer solutions. The solutions were exposed to sonication (intensity 200W, frequency 24 kHz) for 10, 30, and 60 minutes. It was shown that rheological characteristics (viscosity, storage and loss moduli) strongly depend on time of sonication (particularly phase angle) in contrast to electric conductivity and surface tension. For analysis of homogeneous distribution of magnetic field and magnetorheological efficiency (a relation of corresponding ciscosities) was process of electrospinning and resulting wuality of the obtained nanofibrous mats.
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