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Properties of color centers in diamond studied by methods of femtosecond laser spectroscopy
Streshkova, Neli ; Malý, Petr (advisor) ; Dzurňák, Branislav (referee)
In this work, we focus on the interaction of SiV color centers in diamond with femtose- cond light pulses. In the theoretical part, a script is developed to simulate the experimen- tal varying stripe length method and the effects of saturated optical gain are investigated. In the experimental part, photoluminescence and transient differential absorption under non-resonant excitation are studied. The result of the luminescence measurements are estimates of the effective cross-sections of single-photon absorption for the wavelengths 620 nm, 515 nm and 340 nm, as well as the effective cross-section of three-photon absorp- tion for 2000 nm. The result of the differential absorption measurements is the relaxation constant of the excited level of the SiV center and the upper estimate of the time duration of the initial dynamics. 1
Current approaches in the development of vaccines against infectious viral diseases
Vargová, Soňa ; Malý, Petr (advisor) ; Osička, Radim (referee)
Vaccination remains one of the most successful biomedical interventions for preventing viral diseases. While early vaccines were developed by attenuating the infectious agent in cell cultures or by inactivation, new delivery platforms are on the rise thanks to the advent of genetic engineering. The COVID-19 pandemic stimulated the rapid adoption and a massive deployment of these platforms. Viral vector vaccines elicit antigen expression within cells and induce a robust cytotoxic T cell response, unlike protein subunit vaccines conferring mainly humoral immunity. mRNA vaccines also deliver the antigen inside the cells while offering more manageable and faster manufacturing possibilities. Unlike DNA-based vaccines, mRNA does not enter the nucleus, and thus, the probability of disrupting gene expression in the recipient cell is diminished. This thesis aims to offer an overview of current approaches in vaccinology and discuss the various platforms in use. The thesis will also present recent advances in the development of prophylactic vaccines against infections with human immunodeficiency virus-1 (HIV-1) and hepatitis C virus (HCV) and also will focus on a recently proposed strategy for vaccine development based on non-cognate ligands mimicking epitopes recognised by broadly neutralising antibodies...
Photochromic effect in nanoporous titanium dioxide film with Ag nanocrystals
Galář, Pavel ; Malý, Petr (advisor) ; Dohnalová, Kateřina (referee)
The diploma thesis is devoted to multicolour photochromic effect in nanocomposite material Ag-TiO2, which is caused by a spectrally selective photoinduced decrease in extinction. The Thesis introduces briefly the theory of particle plasmons which are of fundamental significance for the investigated phenomenon. A short summary of the models and results published on photochromic effect in Ag-TiO2 is than given. The core of thesis deals with the optimization of this nanocomposite material towards a high photochromatic response. The influence of concentration of the TiO2 solution and of the speed of its spin coating deposition on a substrate was measured. Also the effect of AgNO3 quality used for sample preparation was monitored. A change in the extinction was found to depend on parameters of the excitation laser beam too. As a part of the optimization process, also the alternative TiO2 matrixes produced on basis of lamellar micelles were tested. The photochromic effect was monitored by measurements of the light extinction and scattering in dependence on the sample photoexposition. The properties of a set of the high-quality samples were studied using photoluminescence spectroscopy. Measurements of the photoluminescence decay with subpicosecond time resolution by up-conversion technique as well as of the...
Alternative ECG measurement using flexible electrodes for scanning of electrical potentials on the human body
Hylský, Václav ; Šteffl, Michal (advisor) ; Malý, Petr (referee)
The objective of this bachelor thesis is to measure ECG signal using experimental textile electrodes. The theoretical part deals with heart anatomy, the placement of the heart within the rib cage, heart's electrical activity and ways of measuring it using electrocardiography as well as alternative ECG systems. The practical part of this thesis deals with the use of an experimental ECG T-shirt and wearable electronic equipment. This part also includes the description of the examination method as well as of the equipment which processes and records the signal. The next part this thesis deals with laboratory testing of the experimental ECG T-shirt on a selected sample of people. It also includes an assessment of the measurement results. Keywords: Conductive fabric, electrocardiography, electrocardiogram, electrodes
Novel binding proteins derived from small protein domains targeting diagnostically important molecules
Vaňková, Lucie ; Malý, Petr (advisor) ; Brynda, Jiří (referee) ; Trefil, Pavel (referee)
The rapid development of the gene engineering techniques, especially methods for in vitro directed evolution and combinatorial mutagenesis, has triggered the generation of new binding agents to almost any antigen of interest as an alternative to broadly used antibodies. These so-called non-Ig scaffolds are often derived from proteins with useful biophysical properties. While the therapeutic market is still dominated by monoclonal antibodies, the easy option of desired customization of non-Ig binders by conventional methods of gene engineering predestine them largely for the use in the diagnostic area. The ABD scaffold, derived from a three-helix bundle of albumin-binding domain of streptococcal protein G, represents one of the small non-Ig scaffolds. In our laboratory, we have established a highly complex combinatorial library developed on the ABD scaffold. This ABD scaffold-derived library was used to generate unique binders of human prostate cancer (PCa) biomarkers PSP94, KLK2, KLK11 for the more precise diagnosis of PCa. The second part of the thesis describes the generation of ABD-derived binders selectively recognizing different phenotypes of circulating tumor cells as a binding component of the cell capture zone of microfluidic chip for lung adenocarcinoma diagnosis. Beside this already...
Effect of surface of semiconductor nanocrystals on their properties: investigation by laser spectroscopy
Preclíková, Jana ; Malý, Petr (advisor) ; Franc, Jan (referee)
The topic of the diploma thesis is chemical treatment of the surfaces of semiconductor nanocrystals CdS and CdSe in the form of thin nanocrystalline films prepared by chemical bath deposition. The evolution of photoluminescence and absorption spectra was investigated under treatment by water, toluene, butylamine, pyridine and hydrogen peroxide. The strongest changes were observed by samples soaked in water, pyridine and aqueous solution of pyridine. The observed effects were explained by partly dissolving of nanocrystals by water and affecting behaviour of photoexcited holes in the presence of the strong hole acceptor pyridine. The second part of this diploma thesis deals with photochromic properties of silver nanoparticles in a titanium oxide matrix. The photochromic behaviour of the samples was examined in detail. A phenomenological model of photochromic changes was suggested in analogy with the hole burning spectroscopy. In order to better understand the microscopic processes in this composite material other experiments were realized - e.g. samples were UV irradiated, or laser illuminated under lowered air pressure, pump & probe experiment. Under laser irradiation optical extinction of some nanoparticles was decreased. Simultaneously, changes of plasmon resonances of the rest of nanoparticels were...
Ultrafast laser spectroscopy of semiconductors
Popelář, Tomáš ; Malý, Petr (advisor) ; Oswald, Jiří (referee) ; Žídek, Karel (referee)
This Ph. D. thesis is focused on the study of modern semiconductor materials, diamond, and silicon nanocrystals, by methods of laser spectroscopy. A new experimental setup, the generator of mid-infrared laser pulses, was built to study diamond in detail. With its help, we observed the dynamics of high-density excited carriers, their condensation into electron-hole liquid, and their interaction with light around their plasma frequency. Thanks to the high sensitivity of these measurements on the excited carrier temperature we could observe the thermalisation dynamics which was described by the quantum theory of free carrier absorption. In the doped silicon nanocrystals embedded into SiO2 matrix, we studied the potential presence of free carriers which could be used to create a PN junction. We also found an important recombination channel in these samples which manifests at high excitation intensities. We identified its origin and described its interaction with nanocrystals. At last, we analyzed the influence of incorporated boron atoms on the distribution of decay times according to the emitted wavelength.
Femtosecond absorption spectroscopy for study of stimulated emission
Streshkova, Neli ; Malý, Petr (advisor) ; Zukerstein, Martin (referee)
The aim of the thesis is the building and optimization of an experimental setup for me- asuring the transient transmission and optical gain by the femtosecond pump and probe technique. The setup combines the technology of parametric generation of pump pulses with tunable wavelength and the generation of femtosecond continuum as a spectrally wide probe. In the thesis, conditions of supercontinuum generation in bulk fused silica are extensively studied from a practical viewpoint. The performance of the setup was tested on two types of samples: the solution of rhodamine 6G in methanol and the semiconduc- tor nanocrystalline sample - CdSSe-doped glass. Time resolved spectra of the transient transmission of both samples were measured and the spectral dependence of the optical gain in rhodmine 6G was obtained. 1

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See also: similar author names
9 MALÝ, Petr
2 Malý, P.
13 Malý, Pavel
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