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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.
1

Použití spektroskopických technik pro studium interakcí platinových komplexů a nanočástic s nukleovými kyselinami =:Interactions study of nanoparticles and platinum complexes with nucleic acids assessed by spectroscopic techniques /

Nejdl, Lukáš January 2015 (has links)
The ability of the metal ions to form a covalent bond with the nucleic acids (DNA or RNA) is critical for their structural properties and functions. In the 60s of the last century the potential of platinum complexes in anticancer therapy was revealed. The success of these complexes in anticancer treatment is given by their ability to bind to the DNA bases to form different types of coordination covalent bonds. The formation of these bonds results in an interference of the DNA secondary structure and thereby blocking of important cellular processes such as replication or transcription. Presented thesis examines the ability of metal and semimetal ions (Zn(III), As(III) and As(V)), platinum nanoparticles (PtNPs) and cadmium-based quantum dots (QDs-CdS) to influence the DNA secondary structure. In this work the interactions of metal ions with DNA were firstly investigated due to the implementation and verification of instrumental methods. Results of these studies served as the basis for subsequent experiments dealing with the effects of nanoparticles on eukaryotic cells with regard to DNA damage. In this work we demonstrated that PtNPs show higher affinity for DNA polymerases than to DNA. For this reason, PtNPs can arrest the cell cycle and trigger apoptosis. The affinity rate of nanoparticle binding to DNA is determined by its size, as was shown by the experiments with variously sized CdS-QDs.
2

Luminiscenční nanočástice pro bioanalytické aplikace =:Luminescent nanoparticles for bioanalytical applications /

Vaněčková, Tereza January 2019 (has links)
The dissertation thesis entitled Luminescence nanoparticles for bioanalytical applications deals with the use of optical nanomaterials in life sciences. An overview of the commonly used luminescent nanoprobes is provided together with their advantages over commonly used organic dyes or fluorescence proteins. Next, surface modifications and biofunctionalization of nanoparticles with targeting moieties are discussed. Molecularly imprinted polymers are introduced as an alternative surface modification enabling biorecognition. Finally, theoretical part is concluded with recent examples of the luminescent nanoparticles in bioanalytical and imaging applications. The scientific results of the Ph.D. candidate are presented in the form of 2 review articles and 3 research articles in the peer reviewed journals.
3

Biofyzikální studium malých RNA

Šmerková, Kristýna January 2014 (has links)
Thanks to the prove of connection between the aberrant occurrence of small RNA and various diseases and their potential in diagnostics and treatment led to discovery of new methods and materials facilitating their detection and targeted transport during gene therapy. This work summarizes present knowledge about chosen groups of small RNA, their significance in medical science and the possibilities of their detection. This work primarily concentrates on combination of magnetic separation with electrochemical detection. Magnetic particles (MPs) with different surface modifications were used for isolation. Non-specific isolation was carried out using silanol-coated MPs; streptavidin-coated MPs modified with specific biotinylated probe were used for specific separation. Square wave voltammetry (SWV) was used as a very sensitive electrochemical detection method. Optimized method based on specific magnetic separation with SWV was able to reach nanomolar detection limit (4 nM) with microRNA. The method was applied on human embryonic cells for specific isolation and detection of miR-124. The CdTe quantum dots (QDs) were studied as a nanomaterial tool for nucleic acid detection. The QDs were modified with streptavidin for their bioconjugation with biotinylated molecules were used. Interaction of QDs with nucleic acids was studied using capillary electrophoresis.
4

Quantum dots and their interaction with biomolecules

Stanisavljević, Maja January 2015 (has links)
In this study CdTe QDs were synthetized via microwave irradiation method. Further they have been modified for purposes of their interaction with biomolecules using different conjugation approaches. Applied conjugation chemistries were non-specific interaction, streptavidin-biotin affinity. Glutathione modified CdTe QDs of 2 nm size were capable of non-specific interaction with major groove of DNA, while streptavidin modified CdTe QDs served as specific linker for biotinylated oligonucleotides. Further, streptavidin-biotin interaction was used for coupling of apoferritin and magnetic nanoparticles.
5

Modifikované peptidy ve spojení s kvantovými tečkami

Janů, Libor January 2013 (has links)
In this study, water soluble CdTe QDs of different emission wavelengths were prepared. Microwave synthesis was used to prepare CdTe QDs coated with mercaptopropionic acid (MPA). MPA ensures biocompatibility and good water solubility of QDs. Therefore QDs can be used directly in bioanalytics. Further, QDs modified with biotinylated glutathione (GSH) were prepared. In this case mercapto group (--SH) ensures a bonding of GSH to QDs surface and biotin serves as high specific linker for streptavidin, avidin or neutravidin modified analyte. Finally, peptide mediated immuno-quantum dots were prepared. CdTe QDs were coated with heptamer HWRGWVC which is able to bind Fc region of human immunoglobulin G.
6

Laserová spektroskopie polovodičových kvantových bodů / Laser spectroscopy of semiconductor quantum dots

Pokorný, Martin January 2012 (has links)
This work is focused on examining photoluminescent properties of InAs quantum dots (QDs) on GaAs substrate covered by GaAs1-xSbx strain reducing capping layer (SRL) prepared by Stranski-Krastanow method. We measured luminescence decay time of two samples with different concentration of Sb in this layer. We investigated the influence of temperature, intensity and wavelength of the excitation pulse on the luminescent decay time. We also compared the properties of the samples after excitation by 760 nm pulse and 850 nm pulse - the former one is energetically above the substrate band gap; in the second case we excited only the QDs and the wetting layer (WL). We consequently derived recombination and relaxation processes occurring inside InAs QDs and also the transport of charge carriers from the substrate and the WL into QDs. One part of this diploma thesis was to learn about the methods of measuring ultrafast photoluminescence and build the experimental set-up.
7

Kvantové kritické jevy v konečných systémech / Kvantové kritické jevy v konečných systémech

Kloc, Michal January 2013 (has links)
Singularities in quantum spectra - ground state and excited-state quantum phase transitions - are often connected with singularities in the classical limit of the system and have influence on other properties, such as quantum entanglement, as well. In the first part of the thesis we study quantum phase transitions within the U(2)-based Lipkin model. The relation between quasistationary points of the classical potential and the respective singularities in the spectrum is shown. In the second part, a system of two-level atoms interacting with electromagnetic field in an optical cavity is studied within two simplified models (non-integrable Dicke model and its integrable approximation known as Jaynes-Cummings model). The behaviour of quantum entanglement in these models is shown with a focus on the vicinity of the singular points.
8

Shorův algoritmus v kvantové kryptografii / Shor's algorithm in Quantum Cryptography

Nwaokocha, Martyns January 2021 (has links)
Kryptografie je velmi důležitým aspektem našeho každodenního života, protože poskytuje teoretický základ informační bezpečnosti. Kvantové výpočty a informace se také stávají velmi důležitou oblastí vědy kvůli mnoha aplikačním oblastem včetně kryptologie a konkrétněji v kryptografii veřejných klíčů. Obtížnost čísel do hlavních faktorů je základem některých důležitých veřejných kryptosystémů, jejichž klíčem je kryptosystém RSA . Shorův kvantový faktoringový al-goritmus využívá zejména kvantový interferenční účinek kvantového výpočtu k faktorovým semi-prime číslům v polynomiálním čase na kvantovém počítači. Ačkoli kapacita současných kvantových počítačů vykonávat Shorův algoritmus je velmi omezená, existuje mnoho rozsáhlých základních vědeckých výzkumů o různých technikách optimalizace algoritmu, pokud jde o faktory, jako je počet qubitů, hloubka obvodu a počet bran. v této práci jsou diskutovány, analyzovány a porovnávány různé varianty Shorova factoringového algoritmu a kvantových obvodů. Některé varianty Shorova algoritmu jsou také simulované a skutečně prováděné na simulátorech a kvantových počítačích na platformě IBM QuantumExperience. Výsledky simulace jsou porovnávány z hlediska jejich složitosti a míry úspěšnosti. Organizace práce je následující: Kapitola 1 pojednává o některých klíčových historických výsledcích kvantové kryptografie, uvádí problém diskutovaný v této práci a představuje cíle, kterých má být dosaženo. Kapitola 2 shrnuje matematické základy kvantového výpočtu a kryptografie veřejných klíčů a popisuje notaci použitou v celé práci. To také vysvětluje, jak lze k rozbití kryptosystému RSA použít realizovatelný algoritmus pro vyhledávání objednávek nebo factoring. Kapitola 3 představuje stavební kameny Shorova algoritmu, včetně kvantové Fourierovy transformace, kvantového odhadu fází, modulární exponentiace a Shorova algoritmu. Zde jsou také uvedeny a porovnány různé varianty optimalizace kvantových obvodů. Kapitola 4 představuje výsledky simulací různých verzí Shorova algoritmu. V kapitole 5 pojednejte o dosažení cílů disertační práce, shrňte výsledky výzkumu a nastíňte budoucí směry výzkumu.
9

Diagnostické biosenzory pro encefalopatie způsobené priony

Šobrová, Pavlína January 2013 (has links)
Prion diseases are fatal transmisible neurodegenerative and infectious disorders (TSEs) of humans and animals, characterized by structural transition of the host-encoded cellular prion protein (PrPC) into the aberrantly folded pathologic isoform PrPSc. The main aim of this work is to summarize present information about prion diseases and their possibilities of determination pointed to electrochemical techniques. For this purpose cyclic voltammetry (CV), differential pulse voltammetry, differential pulse voltammetry Brdicka reaction and chronopotentiometric stripping analysis (CPSA) were used. The estimated detection limits were 32 ug/ml by CV, 16 ug/ml by DPV, 16 ug/ml by DPV -- Brdicka reaction and 8 ug/ml by CPSA. Subsequently, the influence of heat denaturation was observed. It clearly follows from the obtained results that signals of prion decreased linearly depending on the duration of the heat treatment at 99°C for various time intervals 0, 15, 30, 45, and 60 min. Moreover, we aimed our attention on studying of prion protein interaction with CdTe quantum dots (QDs) using electrochemistry. Primarily, we characterized electrochemical properties of QDs and the detection limit at 100 fg/ml was estimated. Further, electrochemical study of prion and QD interactions was carried out to find the most suitable conditions for sensitive detection of prion proteins. Detection limit (3 S/N) was estimated as 1 fg in 5 ul. This makes labeling of proteins with QDs of great importance due to easy applicability and possibility to use in miniaturized devices, which can be used in situ. This should open new possibilities how to determine the presence of these proteins on surgical equipment and other types of materials, which could be contagious.
10

Sledování vlivu křemíkových nanočástic na lidské buňky / Effects of silicon nanoparticles on human cells

Bělinová, Tereza January 2017 (has links)
In past years, nanoparticles have been studied as possible platform to be used in biomedicine. In order to establish the application potential of nanoparticles, its impact to biological systems have to be determined. Herein, several silicon-based nanoparticles of different origins were studied in respect of their influence on metabolic activity of human cells, namely osteoblast cell line SAOS-2 and monocytic cell line THP-1. The obtained results proposed that the impact of nanoparticles on cells is highly dependent on cultivation conditions in which nanoparticles are administered to cells. Furthermore, microscopy experiments were implemented in order to localize the particles within cells, where conventional microscopy limitations are evident. Key words: silicon nanoparticles, quantum dots, cell-particle interaction, cytotoxicity

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