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Study of optical properties of organic materials for nonlinear optical applications
Hrbková, Silvie ; Hrabal, Michal (referee) ; Vala, Martin (advisor)
This work deals with a development of a method for determination of two-photon parametres and its application. The theoretical part includes a description of two-photon absorption processes, most frequently used methods to determine two-photon cross sections and a summary of molecules researched to date in the field. The molecules studied in this work are Rhodamin B and Rhodamin 6G in ethanol, which are applied as standards for the implementation of the method. After that, Diketopyrrolopyrroles U24, U37, U49 and U50 dissolved in DMSO, toluene, acetone and chloroform, are researched. Basic optical characteristics - absoption and emission spectra were experimentally acquired for all the materials. Two-photon characteristics were obtained using a picosecond laser and a Two-Photon Excited Fluorescence (TPEF) method. TPA cross-sections and TPA spectra of Rhodamin B and Rhodamin 6G were measured and discussed. Subsequently, this work focuses on absorption and emission solvatation processes of the selected Diketopyrrolopyrroles. These processes indicate their two-photon efficiency. Finally, TPA spectra of the substances are discussed. Contribution of this work is a developed method for measuring the two-photon characteristics suitable for further use. The outcomes achived, enable extensive research of the Diketopyrrolopyrrols characteristics with the use of the measured standards of the Rhodamin B and Rhodamin 6G.
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Modern optical in vivo methods in neurophysiological research
Tomáška, Filip ; Novák, Ondřej (advisor) ; Elsnicová, Barbara (referee)
Accurate visualization of structures and events at subcellular level is one of the major challenges of current neuroscience. Optical methods based on fluorescence imaging were optimized to record and control neural activity, thus presenting a powerful approach complementary to historically dominant electrophysiological techniques. The employment of two-photon excitation enabled in vivo imaging of neurons up to 1 mm from the sample surface without causing significant photodamage. The application of methods of molecular biology has yielded protein-based genetically targetable indicators of neural activity, possessing performance comparable to the traditional organic dyes. Moreover, heterologous expression of microbial opsins proved capable of light-induced neural excitation or silencing in a single-component manner. The combination of these optogenetic tools offers two-way control over neuronal populations with single cell resolution. If coupled with calcium or voltage fluorescent indicators and transgenic animal models, such systems represent a non- invasive, all-optical tool for simultaneous control and imaging of specific neuronal subtypes. Its application supported by electrical recordings may finally provide the data necessary for the uncovering of fundamental principles of neural functioning.
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Modern optical in vivo methods in neurophysiological research
Tomáška, Filip ; Novák, Ondřej (advisor) ; Elsnicová, Barbara (referee)
Accurate visualization of structures and events at subcellular level is one of the major challenges of current neuroscience. Optical methods based on fluorescence imaging were optimized to record and control neural activity, thus presenting a powerful approach complementary to historically dominant electrophysiological techniques. The employment of two-photon excitation enabled in vivo imaging of neurons up to 1 mm from the sample surface without causing significant photodamage. The application of methods of molecular biology has yielded protein-based genetically targetable indicators of neural activity, possessing performance comparable to the traditional organic dyes. Moreover, heterologous expression of microbial opsins proved capable of light-induced neural excitation or silencing in a single-component manner. The combination of these optogenetic tools offers two-way control over neuronal populations with single cell resolution. If coupled with calcium or voltage fluorescent indicators and transgenic animal models, such systems represent a non- invasive, all-optical tool for simultaneous control and imaging of specific neuronal subtypes. Its application supported by electrical recordings may finally provide the data necessary for the uncovering of fundamental principles of neural functioning.
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Improved Methods of Image Acquisition and Analysis of Tissues and Cells by Confocal and Multi-Photon Microscopy
Chernyavskiy, Oleksandr ; Kubínová, Lucie (advisor) ; Hašek, Jiří (referee) ; Malínský, Jan (referee)
Univerzita Karlova v Praze Přírodovědecká fakulta Studijní program: Vývojová biologie (P1520) Studijní obor: Vývojová biologie (1501V000) Oleksandr Chernyavskiy Zdokonalené metody pro snímání obrazových dat a analýzu tkání a buněk pomocí konfokální a multifotonové mikroskopie Improved Methods of Image Acquisition and Analysis of Tissues and Cells by Confocal and Multi-Photon Microscopy Abstrakt disertační práce Školitel: RNDr. Lucie Kubínová CSc Praha, 2015 Abstract The aim of this study was to develop methods and approaches for image acquisition with subsequent image analysis of data, obtained by confocal and two- photon excitation microscopy as well as their combination, enabling new possibilities of visualization and assessment of information on biological tissues and cell structures in 3D and their measurement. We focused on methods that exploited advantages of confocal and multi-photon excitation microscopy. Our further aim was to demonstrate the applicability of non-invasive approach for in vivo applications, usefulness and the relevance of these methods in several special biological applications with emphasis on improved image acquisition, analysis and evaluation of real biological specimens. The present work was not oriented on just one specific biological problem, but rather to methodological...
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Study of optical properties of organic materials for nonlinear optical applications
Hrbková, Silvie ; Hrabal, Michal (referee) ; Vala, Martin (advisor)
This work deals with a development of a method for determination of two-photon parametres and its application. The theoretical part includes a description of two-photon absorption processes, most frequently used methods to determine two-photon cross sections and a summary of molecules researched to date in the field. The molecules studied in this work are Rhodamin B and Rhodamin 6G in ethanol, which are applied as standards for the implementation of the method. After that, Diketopyrrolopyrroles U24, U37, U49 and U50 dissolved in DMSO, toluene, acetone and chloroform, are researched. Basic optical characteristics - absoption and emission spectra were experimentally acquired for all the materials. Two-photon characteristics were obtained using a picosecond laser and a Two-Photon Excited Fluorescence (TPEF) method. TPA cross-sections and TPA spectra of Rhodamin B and Rhodamin 6G were measured and discussed. Subsequently, this work focuses on absorption and emission solvatation processes of the selected Diketopyrrolopyrroles. These processes indicate their two-photon efficiency. Finally, TPA spectra of the substances are discussed. Contribution of this work is a developed method for measuring the two-photon characteristics suitable for further use. The outcomes achived, enable extensive research of the Diketopyrrolopyrrols characteristics with the use of the measured standards of the Rhodamin B and Rhodamin 6G.
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