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Role of interaction between circadian and immune system in development of obesity and type 2 diabetes mellitus
Honzlová, Petra ; Sumová, Alena (advisor) ; Okuliarová, Monika (referee) ; Vodička, Martin (referee)
Disruptions within the circadian, metabolic, and immune systems contribute to the onset of metabolic illnesses, including type 2 diabetes. This doctoral thesis aimed to examine the mutual interactions between these three systems in relation to the development of metabolic disorders. The circadian system regulates a variety of mammalian physiological processes. On the molecular level, the circadian clock is in individual cells maintained by a complex of interconnected transcription-translation feedback loops. The circadian system is hierarchically organized, consisting of the central circadian clock residing within the suprachiasmatic nuclei (SCN) and of peripheral oscillators found in various organs and tissues, including the pancreas and compartments of the innate immune system such as macrophages and microglia. The central circadian clock synchronizes the peripheral oscillators via multiple pathways, including feeding- related metabolic changes to which some of the peripheral oscillators are highly sensitive. Misaligned feeding can thus induce dyssynchrony between individual peripheral oscillators. Our results show that a reverse restricted feeding (rRF) regimen, when food is available only for a limited time during the resting period of the day, has distinct effects on the circadian clocks in...
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Demonstration kit for fiber optic sensing system
Beránek, Karel ; Klíčník, Ondřej (referee) ; Dejdar, Petr (advisor)
This bachelor thesis focuses on the design and implementation of a~demonstration kit for a~fiber optic sensing system. The thesis includes a~theoretical analysis of optical phenomena such as polarization, dispersion, and interference, which are crucial to understanding the principles of fiber optic sensors. The designed sensing system comprises a~Mach-Zehnder interferometer, a~UP-Board development kit, an external 24-bit sound card, and a~touch display. The practical part of the thesis is focused on the construction of the enclosure using 3D printing, the integration of individual components, the design of a~custom application, and the testing of the system. The results of this work contribute to the development of knowledge in the field of fiber optic sensors and can be utilized in both academic and industrial settings.
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Laboratory task - Polarization-based quantum key distribution
Poláková, Sylva ; Münster, Petr (referee) ; Klíčník, Ondřej (advisor)
This bachelor thesis focuses on a detailed analysis of quantum key distribution (QKD) with a focus on one-way prepare-and-measure protocols with discrete variable (DV-QKD) and polarization coding. The thesis is divided into a theoretical and practical part. The introductory theoretical part of the thesis provides a comprehensive overview of polarization as a fundamental physical phenomenon that is essential for understanding the operation of QKD protocols. Various aspects of polarization are discussed, including Jones vectors, Stokes parameters, and the Poincaré sphere. The next section covers the basics of quantum mechanics with a focus on qubit and the representation of quantum states. The work then moves on to quantum key distribution itself, where the basic principles of QKD are explained, and the most important protocols are also analysed. In the practical part, a laboratory task is designed to demonstrate the importance of polarization in the context of QKD protocols.
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Laboratory exercises: Dispersion in optical fibers
Bilek, Maroš ; Klíčník, Ondřej (referee) ; Münster, Petr (advisor)
This thesis first addresses the theoretical analysis of optical fiber transmissions with a focus on the dispersions occurring in optical fibers. Chromatic and polarization mode dispersion are described in detail, including their origin, impact on the transmitted signal, and measurement methods. Based on the theoretical analysis of measurement methods, two were selected for application in the practical part of the thesis, specifically for designing measuring setups for laboratory exercises. The designed setups were practically implemented on several types of fibers with different lengths. The measured values corresponded with predicted theoretical values and met the limit values of the tested fibers. The main output of this thesis consists of two laboratory exercises focused on chromatic dispersion and polarization mode dispersion. These laboratory exercise designs include a brief theoretical analysis of the respective dispersion, specify the necessary limit values and characteristics of the dispersions for evaluating correct results, and implement the measurement method setups for both dispersions. Specifically, these are the pulse delay method for chromatic dispersion and the fixed analyzer method for polarization mode dispersion.
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Design of optoelectronic sensor for biological tissues
Balík, Zdeněk ; Bartlová, Milada (referee) ; Tománek, Pavel (advisor)
Biological tissues are optically inhomogeneous and absorbent materials. They are comprised of various structures such as cells, cell organelles, and various fiber structures. Due to these structures leads to different interactions with the light and phenomena such as absorption, scattering and polarization of light. Different ultrasonic, electromagnetic, electrical and optical methods are used for meat ageing detection. Muscles are turbid anisotropic media, they exhibit changes in electrical and optical properties according to the direction of the electrical and optical fields in the sample. The diploma work assesses the feasibility of impedance measurements for meat ageing detection and their comparison with optical measurement of scattered polarized light. Two different sample were used: pork chop slices and chicken breasts were used for their relative homogeneity. The electrical method is a promising method due to the possibility of getting much information and realizing cheap and fast enough measurement systems. The proposed optical method allows measure the rotation of polarization plane with meat ageing in the range of 95 degrees within considered period. Through the first promising results obtained in this thesis, a further work has to be provided to determine closer relationship between optical scattering characteristics, electrical anisotropy in ageing-related tissue structural properties.
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Utilization of light polarization when filtering the optical signal
Alexa, Jan ; Vlček, Čestmír (referee) ; Wilfert, Otakar (advisor)
This master thesis deals with the possibility of separation of useful signal from noise using polarization of laser radiation. This thesis is structured into 5 thematic units. The first unit is focused on laser radiation and its properties. The second part contains a deeper focus on the polarization of radiation, its description and the possibilities of measuring the polarization states. The third part of the thesis is devoted to the design of the measuring chains and identification of used elements. Chapter four contains measurement of status of the polarization and its results. The last chapter analyzes particular measuring chains outputs according to their spectral characteristics.
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Half Mode Substrate Integrated Waveguide Slot Antennas
Hubka, Patrik ; Schejbal, Vladimír (referee) ; Pánek,, David (referee) ; Láčík, Jaroslav (advisor)
This dissertation deals with the research of slot antennas based on a half-mode substrate-integrated waveguide (HMSIW). By using HMSIW, the physical size of the antenna is reduced by approximately half while maintaining excellent antenna performance. The thesis is consists of two factual parts. The first one (Chapter 4) proposes and describes linearly and circularly polarized HMSIW polarized U-slot antenna. The combination of these two antennas resulted in a polarization reconfigurable HMSIW slot antenna. The functionality of all these antennas are experimentally verified. These antennas achieve better performance compared to current developments of the similar HMSIW antennas. The functionality of the linearly and circularly polarized antenna are further investigated in deep by characteristic modal analysis and parametric procedure. Based on those investigations, design guides of those antennas are proposed. The second one (Chapter 5) deals with design and description of the simple circularly polarized HMSIW U-slot antenna array with linear organization of 1 × 4 basic radiators. The experimental verification proved that the antenna array with a simple feeding network achieved the competitive performance in comparison to the similar antenna array described in the literature.
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Study of Scattering and Polarization of Light in Biological Tissue
Abubaker, Hamed Mohamed ; Hrabovský, Miroslav (referee) ; Číp, Ondřej (referee) ; Tománek, Pavel (advisor)
Tkáňová optika nabývá rychle na významu a přesná znalost optických vlastností biologických tkání je podstatná pro výzkum v biomedicíně i pro kontrolu kvality potravin. Jestliže je vzorek tkáně osvětlen, dochází k mnohonásobnému odrazu světla. V případě postmortem neživých tkání (maso) je rozměr buněk větší než vlnová délka použitého světla. Dochází k Mieovu rozptylu prošlého nebo zpět odraženého světla, v důsledku čehož se objevují různé polarizační stavy světla. Polarizační stavy světla rozptýleného na difúzním prostředí jsou experimentálně zkoumány a modelovány. V práci jsme provedli dva modifikované experimenty: rozptyl polarizovaného světla, které dvakrát prochází vzorkem (vpřed a vzad) a jen světla, které jen prochází vzorkem. Měření rozptýleného světla ukazuje, že dochází k depolarizaci a ke stáčení polarizační roviny, což obojí závisí na orientaci svalových vláken a stárnutí tkání postmortem. Mimo experimentů byl také proveden teoretický popis difúzní biologické tkáně a byla vypočtena radiační přenosová rovnice pomocí modifikované Monte Carlo metody, která zahrnuje polarizační stav světla (PLMC). Je ukázáno, že stupeň polarizace podstatně závisí na optických vlastnostech rozptylového prostředí. Výsledky ukazují, že stav polarizace světla na výstupu závisí na stavu polarizace světla před vzorkem a na optických vlastnostech a tloušťce vrstvy prostředí v průběhu jejího stárnutí. Je také provedena korelace změn polarizace na čerstvosti masa, i popis dynamického chování polarizace při stárnutí masa.
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Dispersion measurements of optical transmissions.
Motúz, Rastislav ; Urban, František (referee) ; Filka, Miloslav (advisor)
This thesis firstly theoretically describes phenomena which appear in optical fiber transmission. The theoretical part of the thesis deals with linear and non-linear phenomena, and later on proceeds to dispersions with a more significant effect on the optical transmission quality. It puts polarization to the centre of the phenomenon called Polarization mode dispersion (PMD), which is the main object of our interest. It leads to a deep PMD description from the point of view of polarization states, limit values, compensation methods, and methods of measurement. The practical part of this thesis deals with a draft of PMD measurement via Fixed Analyzer method. For the purposes of this measurement, we used the optical spectral analyzer MS9740A. In order to compare measured values, the proposed idea then proceeds to the reference measurement by using a modular platform EXFO FTB--200 in combination with CD/PMD module EXFO FTB-5700. Results of measurements have been evaluated for the limit values defined by the standard. In the last chapter of this thesis, the reference measurements are compared to the Fixed Analyzer method. All the advantages and disadvantages of individual measurement methods are identified at the end of this chapter too.
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