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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
111

Vliv anatomické struktury na optické vlastnosti listu vybraných dřevin - vztah k vodnímu režimu. / The effect of leaf structure on the leaf optical properties - Implication for water regime.

Neuwirthová, Eva January 2015 (has links)
Due to coal mining activities, heap substrates rich in clays with poor water permeability and lack of nutrients are relocated outside of mines representing hostile environment to the majority of vegetation. A material from the surface coal mines in Sokolov forming the Velká Podkrušnohorská Heap (VPS) form large locality showing characteristics of anthropogenically devasted landscape. The aim of the present study was to compare leaf structural and biochemical parameters with relation to a leaf reflectance of two pioneer tree species Salix caprea and Populus tremula with regard to leaf water regime and leaf adaptation to a water loss. From the methodological point of view, the study aimed on contribution to determine relation of selected leaf structural parameters to leaf reflectance what has not been intensively studied yet. The foliage of trees P. tremula and S. caprea grown on succession localities S2 a S3 for 30 years was used as a material for my study. The material was studied for its structure using the leaf cross sections nd abaxial epidermal strips (thickness of the leaf tissue layers and of a leaf, stomatal size density and area). Other studied parameters were contents of photosynthetic pigments, specific leaf area (SLA), water potential and leaf reflectance in regions of photosyntetically...
112

Alternativní metody zobrazení pankreatických ostrůvků. / Alternative methods for visualization of pancreatic islets.

Gálisová, Andrea January 2018 (has links)
Transplantation of pancreatic islets (PIs) represents an alternative treatment for type 1 diabetes mellitus. Post-transplant monitoring of islets by a reliable imaging method may contribute to the improvement of the transplantation outcome. In this thesis, novel visualization approaches for PIs were tested using magnetic resonance (MR) and optical imaging on phantoms and experimental animals, including Chemical Exchange Saturation Transfer (CEST) MR, fluorine (19 F) MR, bioluminescence and fluorescence imaging. MR imaging based on frequency-selective method CEST was performed on islets labeled with Eu-/Yb-based chelates. Labeled islets possessed low MR signal in phantoms, what would have been unsatisfactory for in vivo applications. Moreover, viability and function of labeled islets was impaired reflecting limited applicability of these agents for islet labeling and visualization. Genetically modified bioluminescent islets showed suitable properties for longitudinal tracking of their post-transplant fate at an artificial transplant site - subcutaneously implanted polymeric scaffolds. Using multimodal imaging (MR and bioluminescence), the optimal timing for transplantation of islets into the scaffolds was assessed in diabetic rats. Islets transplanted into scaffolds using the optimized timing scheme...
113

Využití speciálních optických metod v diagnostice benigních a maligních slizničních lézí horních cest dýchacích a polykacích. / Application of special methods in diagnostics of benign and malignant mucosal lesions of upper aerodigestive tract.

Zábrodský, Michal January 2019 (has links)
Optical imaging methods incorporating observation of the mucosal surface of organs with narrowband filtered light are diagnostic tools with a significant development in recent years and have become an integral and inseparable part of the diagnostic process of benign and malignant pathologies of the mucosal surface of various anatomical systems of the human body. Malignant and premalignant lesions of the upper aero-digestive tract (UADT) are no exception. The present work demonstrates the benefits of evaluation of changes in microvascular architecture by narrowband imaging. Its major advantage is a more accurate diagnosis of premalignant and malignant mucosal pathologies in the head and neck region based on the identification of significant changes in superficial vascularity. There is a very strong correlation of these vascular changes with the final histopathological analysis. The present data have shown that videoendoscopic examination with narrowband imaging significantly improves the distinction between benign and malignant mucosal lesions even in the UADT pathologies with a similar tendency to neoangiogenesis (squamous cell papilloma vs. squamous cell carcinoma). It also refines the determination of surface extension of tumoral changes and helps to localize and accurately diagnose tumors of...
114

Vliv teploty na vznik arytmií během vývoje srdce / Effect of temperature on arrhythmogenesis during heart development

Vostárek, František January 2018 (has links)
5 Abstract: Aims: The main objective of this work was to analyze in detail the effects of acute temperature changes on the function of isolated chick embryonic heart in vitro in comparison with natural conditions in ovo. Methods: The effects of temperature change (34 řC, 37 řC and 40 řC - hypo-, normo- and hyperthermia, respectively) on calcium dynamics in four days old isolated chick hearts in vitro were investigated by high-speed calcium optical imaging. For comparison and validation of in vitro measurements, experiments were also performed in ovo using videomicroscopy. Artificial electrical stimulation experiments were performed in vitro and in ovo to uncover conduction limits of different heart segments. Results: We observed almost linear dependence of sinus frequency on temperature in our temperature range. Sinus frequency during hypothermia and hyperthermia in vitro and in ovo changed about 20% in comparison with normothermia. We observed no significant changes in amplitude of calcium transients during temperature change to hypothermia but hyperthermia caused a significant decrease in amplitude of calcium transients (atria 35%, ventricles 38%). We observed a wide spectrum of arrhythmias, which occurred spontaneously even during normothermia in vitro. Occurrence of arrhythmias in vitro significantly...
115

Mechanismy vývoje převodního systému srdečního u obratlovců / Mechanisms of conduction system development in vertebrates

Šaňková, Barbora January 2016 (has links)
Group of specialized cells that form cardiac conduction system is responsible for generation and coordinated propagation of the electrical impulse in the heart. Changes in its development can be connected with arrhythmias; therefore, a good level of knowledge is necessary and relevant for basic science and clinical practice. For correct development of the conduction system are important genes coding gap junctions proteins, ion channels, transcription factors and other molecules involved in signaling cascades (endothelin, neuregulin). Development of conduction system is determined in addition to genetic factors also by epigenetics and environmental factors. This thesis with its individual papers on which it is based is addressing different aspects of conduction system development, which appears to be a complex process. Another feature which is linking all papers together, is the methodological approach enabling us to study function of the conduction system - optical mapping. In the first publication we studied by the means of in vitro organ culture the impact of work load without interfering hemodynamics on the conduction system maturation in the chick embryonic heart. The phenotype observed during experiments was developmental regression of conduction system maturation together with changes in...
116

Disperzní vlivy optických vláken na multiplexní přenosy / The Optical Fibre Dispersion Effects on Multiplex Transmission Systems

Kyselák, Martin January 2009 (has links)
This doctoral thesis deals with present trend to turn up the bit rate of the optical fibres making use of wavelenght multiplex systems. There are new theoretical and practical problems caused by the new technologies. Except the known modal dispersion there exist problems caused by chromatical and polarization mode dispersion. In the opening of the thesis the known effects, which influence the payload signal, are introduced. The polarization mode dispersion has the main attention. Within the scope of this thesis there has been programmed the statistical calculator which can analyses the measured values of differential group delay by Monte Carlo calculation. Next meaningful output is the designating application of the optical routes. It is possible to mathematicaly unambiguously define the polarization mode dispersion by Jones, Stokes and Poynting vectors. This complicated calculations are mechanized and in the simulation application make possible to simulate the signification of the PMD influence at different input parameters. The thesis includes the study of the PMD modulation format impact with the results of simulations and confrontation with other scientists results. The significant output are the final practical results examinations, which can be implemented thanks to the possibility of using the FTB-5500B measuring device.
117

Optical Micromanipulation Techniques Combined with Microspectroscopic Methods / Optical Micromanipulation Techniques Combined with Microspectroscopic Methods

Pilát, Zdeněk January 2015 (has links)
Předložená dizertační práce se zabývá kombinací optických mikromanipulací s mikrospektroskopickými metodami. Využili jsme laserovou pinzetu pro transport a třídění živých mikroorganismů, například jednobuněčných řas, či kvasinek. Ramanovskou spektroskopií jsme analyzovali chemické složení jednotlivých buněk a tyto informace jsme využili k automatické selekci buněk s vybranými vlastnostmi. Zkombinovali jsme pulsní amplitudově modulovanou fluorescenční mikrospektroskopii, optické mikromanipulace a jiné techniky ke zmapování stresové odpovědi opticky zachycených buněk při různých časech působení, vlnových délkách a intenzitách chytacího laseru. Vyrobili jsme různé typy mikrofluidních čipů a zkonstruovali jsme Ramanovu pinzetu pro třídění mikro-objektů, především živých buněk, v mikrofluidním prostředí.
118

Vliv dávkování genu Nkx2.5 na vývoj a elektrofyziologii srdce u myši / Role of Nkx2.5 on development and electrophysiology of the mouse heart

Hámor, Peter January 2015 (has links)
Role of Nkx2.5 on development and electrophysiology of the mouse heart Prague 2015 Bc. Peter Hámor ABSTRACT The objective of this thesis is to investigate the role of Nkx2.5 gene dosage on electrophysiology of the mouse heart in prenatal stage of its development, in which the physiological functions of the heart fail to function properly. The main goal of this work is to search for differences in conduction of electric impulses through the embryonic mouse heart according to their genotype. Special method of capturing the conduction of electric impulse through myocardium was used for this purpose, called optical mapping. Thanks to this method I was able to construct images and videos capturing transition of the impulse with marked beginning of the activation and its direction in the heart. These outputs, or optical maps, help to define anomalies and defects compared with a normal functioning heart. The thesis focuses on the expression of the transcription factor Nkx2.5 and regulatory components related with the correct formation and physiology of the heart until 9.5 days post coitum. Individuals in this developmental stage were optically mapped and compared according to their genotypes - homozygous non-mutant, heterozygote and homozygous mutant mouse embryos exhibited some degree of similarity, while other...
119

Role genu Nkx2.5 v morfogenezi a elektrofyziologii srdce u myši / Role of Nkx2.5 in development and electrophysiology of the mouse heart

Hámor, Peter January 2016 (has links)
Role of Nkx2.5 in development and electrophysiology of the mouse heart Prague 2016 Peter Hámor, B.S. ABSTRACT The objective of this thesis is to investigate the role of Nkx2.5 gene dosage on electrophysiology of the mouse heart in prenatal stage of its development. The main goal of this work is to search for differences in conduction of electric impulses through the embryonic mouse hearts of different genotype. Special method of capturing the conduction of electric impulse through myocardium, called optical mapping, was used to visualize the electrical activity. Thanks to this method I was able to construct images and videos capturing the spread of the impulse with identification of the beginning of the activation and its direction in the heart. These outputs, or optical maps, help to define anomalies and defects in mutants compared with a normal functioning heart. The thesis focuses on the expression of the transcription factor Nkx2.5 and regulatory components related with the correct formation and physiology of the heart until 9.5 days post coitum. Embryos at this developmental stage were optically mapped and analysed according to their genotype. While the wild type and heterozygote mouse embryos exhibited high degree of similarity, the homozygous mutants were dramatically different. Considering this work...
120

Lokalizace vibrace v okolí optického vlákna pomocí interferometrického senzoru / Location of vibration around the optical fiber

Dorazin, David January 2018 (has links)
This diploma thesis solves possibilities of utilization optical fiber as sensor. At the beginning, basic division of this sensors is desribed, their principles and usage. Then the thesis is focused on distributed sensors based on the interference of the light, interferometers. This optic fiber interferometers are described, mainly their modifications for detection and localization of vibrations along optical fiber. Significant part of the thesis deals with dual Mach--Zehnder interferometer. This interferometer is theoreticaly desribed and simulated in Matlab. Further the thesis deals with development of two aplication in Matlab software. One application is for simulation and theoretical computation of dual Mach--Zehnder interferometer. Second application serves for signal processing of acquired data that are measured on this interferometer. At the end of the thesis, dual Mach--Zehnder interferometer is designed and build in laboratory enviroment and executed measurement and localization of vibrations using this interferometer.

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