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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.
131

Kostní implantáty na bázi řeleza a hořčíku / Bones implants based on Fe and Mg

Košíček, Adam January 2016 (has links)
This paper work deals with properties of metallic biomaterials in terms of their suitability for use as a temporary metal implants. The work focuses on biodegradable materials based on iron and suitable alloying elements, which would create a perfect implant. A part of this work describes procedure of creating biodegradable metallic samples with alloying element Magnesium and measuring the corrosion rates. There are a few theoretical chapters concerning permanent implants, function and composition of human bones, iron and magnesium in human body and biodegradable materials.
132

Studium titrace molekulárního kyslíku do dohasínajícího dusíkového plazmatu / Study of molecular oxygen titration into nitrogen post-discharge

Řehulková, Blanka January 2017 (has links)
A huge number of experiments were carried out in the field of nitrogen post-discharges during the last 50 or 60 years and they were supported by many published theoretical works. Some papers were focused also on the nitrogen active discharge, post-discharge itself, or they focused mainly on the kinetic processes running during the post-discharge period. This experimental work shows how oxygen titration into post-discharge will influence nitrogen flowing post-discharge. Experimental data were obtained by optical emission spectrometry, Spectra were measured in the range 300 - 700 nm at laboratory temperature of 300K. Discharge current was kept constant at the value of 120 mA relating to the total discharge power of 145 W. Pressure was kept constant, too, at the value of 1000 Pa. The nitrogen of 99.9999 % purity (further purified by Oxiclear column) flow was adjusted at 0.8 l/min. Flow of oxygen (99.95 % purity) through he titration capillary introduced to post-discharge from down stream direction, was kept at 4 ml/min. Both gas flows were controlled by mass flow controllers. The optical emission spectrometer Jobin Yvon TRIAX 550 with 300 gr/mm grating equipped by liquid nitrogen cooled CCD detector was used for the spectra acquisition. The integration time of 1 s was used at all experiments. The position of titration tube end introduced into post discharge from the down stream side was set from 5 to 25 cm with respect to the end of the active discharge; the step of 1 cm was used. The optical emission spectra were measured at positions from 3 to 29 cm with respect to the active discharge end. The following nitrogen spectral systems were identified in the spectra: 1st positive, 1st negative and 2nd positive. Besides them, some bands of NO-beta system were found. The intensity profiles along the post discharge were obtained for selected vibrational spectral bands of these spectral systems and changes in the vibrational distributions of upper electronic states of these spectral systems were determined.
133

Korelační vlastností fluktuací v přechodové oblasti / Correlation properties of magnetosheath fluctuations

Gutynska, Olga January 2011 (has links)
Title: Correlation properties of magnetosheath fluctuations Author: Olga Gutynska Department: Department of Surface and Plasma Science Supervisor: Prof. RNDr. Jana Šafránková, DrSc. e-mail address: Jana.Safrankova@mff.cuni.cz Abstract: This thesis deals with fluctuations of the magnetic field (MF) and plasma density in different magnetosheath locations. The statistical study of the correlation length of these quantities has shown that these lengths are surprisingly low for both the ion flux and MF (approx. 1 RE). However, the correlation length increases with an increasing correlation between the magnetosheath and interplanetary magnetic fields (IMF). Further, we have found that the correlation length of MF fluctuations depends on the solar wind speed, on a correlation between IMF and magnetosheath MF fluctua- tions, and on the amplitude of fluctuations. The statistical study of radial profiles of cross-correlations between MF and plasma density at the subsolar and flank regions based on Cluster and THEMIS magnetosheath observa- tions revealed better correlations toward the magnetopause. A study of the modification of the IMF direction in the magnetosheath has shown that a reliable prediction of the magnetosheath BZ sign requires |IMF BZ| > 2 nT and that this prediction is more precise during solar minimum....
134

Nanostrukturované plazmové polymery pro řízenou imobilizaci biomolekul / Nano-structured multicomponent plasma polymers for controlled immobilization of biomolecules

Melnichuk, Iurii January 2017 (has links)
Title: Nano-structured multicomponent plasma polymers for controlled immobilization of biomolecules Author: Iurii Melnichuk Department / Institute: Department of Macromolecular Physics/Charles University Supervisor of the doctoral thesis: Doc. Ing. Andrey Shukurov, Ph.D. Abstract: The aim of this thesis is to highlight the feasibility of tailored nano- structures in functionalizing surfaces for biointerfacial interactions. Development of new techniques for the production of nanoscaled biomaterials can be of use in a variety of medical and biological applications, e.g. biosensors, microarrays, drug sensors, implants, blood-contacting devices. This thesis first examines the early stages of nano-structured thin film growth fabricated by vapor phase deposition of poly(ethylene). We discuss island growth within a framework of rate equation theory, dynamic scaling theory and capture zone distribution. In a second stage, we test dielectric barrier discharge to activate PE nano-pattern for covalent immobilization of proteins. Finally, we assess cell behavior on surfaces in dependence on morphology and the presence of cell adhesive protein tropoelastin. We employ plasma polymerization to produce ultrathin hydrocarbon layer capable of protein anchoring. The thesis findings for the first time manifest the critical...
135

Reakce iontů s molekulami H2 a rekombinace iontů H+3 s elektrony při kryogenních teplotách / Reactions of Hydrogen Molecules with Ions and Recombination of H+3 Ions with Electrons at Cryogenic Temperatures

Hejduk, Michal January 2013 (has links)
We studied how distribution of nuclear-spin states of H+ 3 ions or H2 molecules influence rate coefficients of H+ 3 -electron recombination or reactions of H2 with N+ or H+ , with regard to kinetic and internal temperatures of the reactants. Experiments were carried out in plasma environment or in an ensemble of ions in an ion trap. Main diagnostic methods were the Langmuir probe diagnos- tics, laser absorption- and mass spectroscopy. The distribution of nuclear spin states (para and ortho) was varied using a specially constructed para-hydrogen generator. We performed pioneer measurements of the rate coefficients for the nuclear-spin-state-selective binary and ternary H+ 3 -electron recombination in thermalised plasma. We performed studies of N+ + para/ortho-H2 reaction with high accuracy and interpreted the results as dependent on fine structure states of N+ ions. We measured a temperature dependence of the rate coeffi- cients for radiative and ternary channels of H+ + para/ortho-H2 association. 1
136

Postpartální exprese kardiovaskulárních mikroRNA - srovnání expresních hladin mezi plazmou, plazmatickými exozómy a plnou periferní žilní krví / Postpartum expression of cardiovascular disease-associated microRNAs - comparison of expression levels between plasma, plasma exosomes and whole peripheral venous blood

Ševčíková, Adéla January 2021 (has links)
MicroRNA (miRNA) are short non-coding RNA molecules that regulate gene expression at the post-transcriptional level. Many miRNAs are involved in the pathogenesis of cardiovascular diseases, which is associated with altered gene expression. This work compares miRNA gene expression profiles among various biological sources - whole peripheral venous blood (whole PB), plasma and plasma exosomes. For all tested groups combined, the expression levels of miRNA were maximal in whole PB and lowered in plasma and plasma exosomes, and the expression levels of miRNA were higher in plasma than in plasma exosomes, except miR-126-3p, which had a higher level detected in plasma exosomes compared to plasma. This work also compares expression levels of cardiovascular miRNA between women with anamnesis of gestational diabetes mellitus (GDM) and physiological gravidity 3-11 years postpartum in whole PB, plasma and plasma exosomes. In whole PB, 12 of 29 tested miRNAs were up-regulated in women with prior exposure to GDM. MiR-181a-5p was up-regulated in plasma exosomes and miR-499a-5p in plasma in women with prior exposure to GDM. The changes in whole peripheral venous blood seem to reflect the complex systemic response to the changes that occurred during the onset of GDM. Women with aberrant epigenetic profiles may...
137

Studium dohasínajícího dusíkového plazmatu pomocí titrace rtuťových par / Study of nitrogen post-discharge by mercury vapor titration

Teslíková, Ivana January 2012 (has links)
The aim of this master thesis is a study of nitrogen post-discharge by mercury vapours titration. The nitrogen post-discharge is investigated for many years theoretically as well as for a practical use. The object of this master thesis is a study of kinetic processes ongoing at titrations of mercury vapours during the nitrogen post-discharge at different pressures and applied powers. All experimental data were obtained from an optical emission spectroscopy of nitrogen post-discharge. DC discharge in flowing regime was chosen for measurements. The first part of experiments was carried out at the constant discharge current (100 mA), voltage (1300 V) and wall temperature (300 K). The total gas pressure was varied in range of 500-3000 Pa at nitrogen flow in range of 0.12-0.68 l/min. Nitrogen flow values were arranged to obtain constant nitrogen flow velocity for all gas pressures. The second set of experiments studied power dependencies. The current was varied in the range of 50-200 mA for constant voltage 1300 V. The total gas pressure in this case was 1000 Pa. Mercury vapours were introduced into the system by titration tube at different post-discharge time. The nitrogen pink afterglow effect was well visible at all experimental conditions. This effect corresponds to the maximum intensity of light emission, which expresses as considerable growth of characteristic pink radiation in the post-discharge time. Optical emission spectra of post-discharge were taken in the range of 320-780 nm. Besides three nitrogen spectral systems (first and second positive and first negative), the mercury line at 254 nm was recorded in the second order spectrum at 508 nm under these conditions if mercury was added. This spectral line is excited under post-discharge conditions by collisionally induced resonance energy transfer from nitrogen highly vibrationally excited ground state metastables and it opens an unique technique for their monitoring. The dependence of relative intensities on decay time for mercury spectral line and selected nitrogen spectral systems at different titration positions were measured. The relative intensities of nitrogen bands decrease with increasing of mercury line relative intensity for all total gas pressures. The pink afterglow phenomenon shifts to the later decay times with the increasing of total gas pressure. In the case of experiments at different power, it can be seen that with decreasing power mercury spectral line intensity decreases in post-discharge time. The first detailed tests of the unique detection for highly excited of nitrogen metastables were completed. However this master thesis is concentrated on the basic research which supports better indication of kinetic processes and reactions leading to transformation of excitation energy, this new knowledge should be applied in future also in technologies based on the long-lived metastable induced reactions.
138

Využití gelově-založených proteomových technik při analýze genové exprese u prokaryotních a eukaryotních modelů / Analysis og gene expression in prokaryotic and eukaryotic model organisms by proteomic gel-based separation tools

Petráčková, Denisa January 2011 (has links)
This PhD thesis showed the applicability of a gel-based proteomic separation tool, 2-D electrophoresis in three independent projects. Supplemented with results obtained using different techniques the proteomic studies enabled a global imaging of proteoms in the studied biological systems. Comparing total proteoms of E. coli 61 protein changes were identified and connected with the development of the bacterial population in the presence of an antibiotic compound, erythromycin. This classic proteomic approach included sample extraction, optimization of its 2D separation followed by 2D gel analysis and protein identification by MS methods. A disadvantage of this work was an enourmously large amount of data to be analyzed by computer analysis. For the study of membrane proteom of B. subtilis during a pH induced stress, on the other hand, a modification of isolation techniques for membrane and membrane associated proteins was required first to improve the subsequent protein separation by 2-D electrophoresis. The optimalization of protein extraction included changes in detergents used for protein solubilization and a prolongation of time periods in the protein solubilization protocol. 5 relevant protein changes were then described that play a role in the bacterial response to pH stress. The proteins were...
139

Optimalizace depozičních parametrů za účelem vytvoření fotokatalytických titanoxidových vrstev metodou PECVD / Optimization of deposition parameters in order to create a photocatalytic titanium oxide films produced by PECVD

PEKÁREK, Michal January 2013 (has links)
This thesis presents Photocatalytic TiOx layers created by own PECVD reactor assembled in the building of Department of Applied Physics and Technics. Parameters of depositions were optimalized as well as the PECVD reactor itself. Final layers are compared to layers made by Degussa P25. As a result based on the included measurements, this thesis tries to answer the question whether PECVD is the suitable method for depositions of photocatalytic layers.
140

Plazmatický výboj generovaný surfatronem s frekvencí 2,45 GHz / Plasma discharge generated by surfatron with frequency 2,45 GHz

HOUSER, František January 2007 (has links)
This diploma thesis deals mainly with utilization of plasma in technological aplications. The introductory part is apllied to the theoretical description of plasma generated by the surfatron. This launcher works with the frequency of 2,45 GHz and it is able to excite the surface wave, that sustains plasma column in a quartz tube. Plasma generated by surfatron was used for modification of surface properties of polyethylen to change its surface energy. By changing of surface energy it was reached of higher hydrophilicity. Plasma generated by surfatron was diagnosed in detail during experiments in a continual regime as well as in a pulse one with a help of a single {--} probe and a double {--} probe Langmuir measurement. In this diploma thesis there is discussed influence of pressure, power and other experimental options.

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