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Carbon nanoparticles from South Moravian lignite
Drozdová, Miroslava ; Enev, Vojtěch (referee) ; Pekař, Miloslav (advisor)
This bachelor thesis deals with the issue of isolation of carbon nanoparticles from lignite, which seems to be their cheap source. The aim of this work is to elaborate a research on the use of coal matrices as a source of carbon nanoparticles and also to design and perform further experiments testing the usability of South Moravian lignite. Based on the literature search, a simple mechanochemical procedure was proposed to obtain carbon nanoparticles from lignite. The lignite was mechanically stressed by the ultrasonic disintegrator with simultaneous action of water or hydrogen peroxide. Lignite has been able to isolate particles fluorescing in the blue visible light, but the process will need to be further modified. However, South Moravian lignite could be a source of carbon nanoparticles.
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Microstructure of carbon black nanomaterials studied by X-ray scattering
Machovec, Petr ; Dopita, Milan (advisor) ; Horák, Lukáš (referee)
Název práce: Studium mikrostruktury uhlíkových nanomateriálů pomocí rentgenové difrakce Autor: Petr Machovec Katedra: Katedra fyziky kondenzovaných látek Vedoucí bakalářské práce: RNDr. Milan Dopita, Ph.D., Katedra fyziky kondenzovaných látek Abstrakt: Předkládaná práce se zabývá studiem mikrostruktury, struktury a reálné struktury turbostratického uhlíku a uhlíkových nanotrubic pomocí metod rozptylu rentgenového záření. Klastry turbostratického uhlíku jsou popsány pomocí sady fyzikálních parametrů. Pomocí počítačových simulací je popsán vliv těchto parametrů na výslednou rozptylovou křivku. Dále je předkládán popis dvou typů uhlíkových nanotrubic a je popsán vliv typu a rozměrů uhlíkových nanotrubic na výslednou rozptylovou křivku. Pro experimentální část práce byla připravena série vzorků turbostratického uhlíku žíhaného při teplotách 300℃, 600℃, 800℃, 1000℃, 1200℃, 1400℃ a 1800℃. Pomocí maloúhlového rozptylu rentgenového záření byla určena velikost nanočástic a jejich rozdělení, velikost mikropórů, specifický povrch a dimenze povrchového fraktálu. Další fyzikální parametry jako velikosti a rozdělení velikostí klastrů La a Lc turbostratické uhlíku, mřížové parametry a a c a střední kvadratické výchylky atomů ve směru grafenových vrstev a ve směru kolmém byly určeny z širokoúhlových rentgenografických...
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Functionalized Polystyrene Nanomaterials for Biomedicinal Applications
Dolanský, Jiří ; Mosinger, Jiří (advisor) ; Dědic, Roman (referee) ; Zimčík, Petr (referee)
Nowadays, there is an increasing risk of bacterial infections from bacteria strains resistant towards antibiotics. Thus, it is of utmost importance to research novel therapies which can overcome this difficulty. The presented thesis focuses on the preparation, characterization and antibacterial evaluation of polystyrene polymer nanomaterials (nanofiber membranes and nanoparticles) modified with compounds that can efficiently inhibit bacterial growth either by their nature (polyethyleneimine) or by photoactivation upon visible light excitation (NO- photodonors, photosensitizers) and consequent production of highly reactive inorganic bactericidal species, nitric oxide (NO) and singlet oxygen (O2(1 g)). All materials were fully characterized by several independent methods. The concentrations of NO and O2(1 g) were measured by amperometric and time-resolved spectroscopic techniques and by variety of chemical analytic procedures. Due to the presence of bactericidal species and the efficient photogeneration of NO and O2(1 g) at physiological conditions, all materials exhibit strong antibacterial action tested on a Gram-negative bacterial strain Escherichia coli. Hence, these functionalized polymer nanomaterials may be intriguing systems for medical-, biological-, or environmental- application where a...
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Adhesion, growth and differentiation of osteoblasts and mesenchymal stromal cells on biocompatible nanomaterial surfaces
Brož, Antonín ; Hubálek Kalbáčová, Marie (advisor) ; Černý, Jan (referee) ; Kylián, Ondřej (referee)
The thesis is based on articles describing the fundamental research of carbon based nanomaterials for their possible utilization in biomedicine. The aim of this thesis was to describe the way how human osteoblasts (SAOS-2 cell line) and primary human mesenchymal stem cells (hMSC) adhere, grow and behave on surfaces made of several carbon allotropes - nanocrystalline diamond (NCD), single walled carbon nanotubes (SWCNTs) films and graphene. The utilization of carbon as the basic material promised good biocompatibility and possibility of useful surface modifications. The NCD had modified surface nanotopography (nanoroughness and nanostructuring prepared by dry ion etching). All the materials had modified surface atomic termination with oxygen and hydrogen which changes the surface electrical conductivity, surface charge and wettability. It was hypothesized that the surface termination can also influence the cell adhesion and growth. It turned out that all the studied materials were suitable as substrates for cultivation of mentioned cell types. Various nanoroughnesses of NCD surface had different effect on the cell adhesion and cell metabolic activity. Nanostructuring of the NCD influenced the formation of focal adhesions. The surface terminations of NCD and the other studied nanomaterials in...
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Structure and magnetic interactions in nanomaterials with application potential
Pacáková, Barbara ; Kalbáčová Vejpravová, Jana (advisor) ; Jirásková, Yvona (referee) ; Svoboda, Pavel (referee)
The thesis is focused on the physics of magnetic nanoparticles (NPs), starting from the solution of magnetic structure, internal alignment within the single particle and role of interactions and particle structure in magnetic response of systems of the NPs. Moreover, the macroscopic arrangement of the NPs and its effect on the properties of system containing the NPs are discussed. The work brings several new results and concepts, such as the solution of magnetic structure of the ε-Fe2O3 phase, methods of proper detection and description of magnetic metal catalyst in carbon nanotubes and role of the NP arrangement and their effect on graphene placed on the top of substrates decorated with the NPs. 1
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Optimization and application of assays for determination ecotoxicity of nanomaterials
Semerád, Jaroslav ; Cajthaml, Tomáš (advisor) ; Kočí, Vladimír (referee)
This thesis deals with optimization and application of assays for determination of ecotoxicity of nanomaterials based on nanoscale zero-valent iron (nZVI), which are used in remedial technologies. After in situ application of nZVI, a significant decrease in toxicity of polluted environment was detected; however, a potential negative effect of nanoparticles has not been sufficiently investigated yet. Standard used tests were found to be incompatible with nZVI for toxicity determination. Specific characteristics of nZVI, such as high reactivity and sorption, complicate determining the toxicity by routinely used ecotoxicity tests. Concentration ranging from 0,1 to 10 g/l that are used in practise for decontamination were tested. These concentrations resulted in formation of turbidity, which prevented the use of standard tests. In this work, a new method has been optimized for in vitro toxicity testing of nZVI and derived nanomaterials using bacteria. The principle of this assay is determination of oxidative stress (OS). The disbalance between formation and degradation of reactive oxygen species (i.e. OS) leads to irreversible changes in biomolecules of organisms and formation of undesirable products. A toxic and mutagenic product - malondialdehyde (MDA) is formed during lipid peroxidation and it is a...
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Carbon nanomaterials and their interactions with bacteria
Jurková, Blanka ; Beranová, Jana (advisor) ; Kuthan, Martin (referee)
Recently, carbon nanomaterials gain attention especially for their interesting, often unique, properties. They can be used in wide range of applications, such as electronics, optics, cosmetics, solar cells, construction materials, air filters, polishing materials, protective coatings and dry lubricants. Whereas their physical and chemical attributes have already been intensively examined, the research on their effects on living organisms is still at the preliminary stage. This work is focused on the interactions of carbon nanomaterials, namely graphene, fullerene, carbon nanotubes and nanodiamonds, with bacterial cells and their antibacterial and antiadhesive properties. The mechanisms of the toxic action of carbon nanomaterials against bacteria include damage of outer cell structures as a consequence of the direct contact with a nanomaterial, impairment of bacterial metabolism or reactive oxygen species production. Exact understanding of the processes that take place between bacterial cell and carbon nanomaterials can contribute to the research on their medical applications and ecological recycling in the future.
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Regulation of genetically modified organisms and nanotechnology : (comparison of British, Czech and Slovak legislation in the context of EU)
Zemaník, Vladimír ; Damohorský, Milan (advisor) ; Žákovská, Karolina (referee)
Regulation of genetically modified organisms and nanotechnology (comparison of British, Czech and Slovak legislation in the context of EU) The aim of this thesis is to first compare the british, czech and slovak legislation relating to genetically modified organisms. By the analysis of their respective features, the author points out the difficult bits and tries to look for the ideal solutions to the current problems of the european GM legislation. In spite of the fact, that the european legislation in this field is highly harmonised, there are still some areas that can be regulated by the member states as well as some holes waiting to be fixed. This thesis is composed of six main chapters which correspond to six main topics of present biotechnology legislation that are in the author's opinion the most significant. First chapter deals with the basic issues of releases of genetically modified organisms into the environment, on market, and with their contained use. Secondly, the author dissects the GM labelling and traceability legislation and shows the various thresholds of GM presence that are applicable to different areas. Third chapter then analyses the rules on co-existence between GM plants on one hand and conventional and organic plants on the other. Nextly, the unilateral acts of member...
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Toxicity of nanomaterials to aquatic crustaceans
Novotná, Kateřina ; Kočí, Vladimír (advisor) ; Cajthaml, Tomáš (referee)
Nowadays, nanomaterials are broadly used for many purposes thanks to their unique properties. The production of nanoscale materials is growing rapidly. Consequently, it means a high probability of their release into the environment and there are concerns about their possible negative effects on organisms. Furthermore, the behaviour of nanomaterials might be strongly influenced by many factors and there are many different types of them, so there is still a big information gap in this field. The aim of this work is to summarize basic facts about nanomaterials and their possible toxicity, especially to the fresh-water crustacean Daphnia magna. An impact of nanoscale zero-valent iron particles is tested on this species. This material is used for remediation so it is injected directly into the environment. Concentrations of 0,1 g·l-1 , 0,5 g·l-1 , 1 g·l-1 and 2,5 g·l-1 of two products with different surface modifications were tested. It was found that the toxicity depends on the type of stabilization. EC50 was not established for NANOFER 25S (with a special surface modification) due to the maximum immobilization rate of only 30 % for the concentrations tested. However, the EC50 value for NANOFER 25 (without the special surface modification) is 0,94 g·l-1 . These results confirm that it is necessary to...
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Ecotoxicity of nanomaterials
Viltová, Naďa ; Kočí, Vladimír (advisor) ; Motejlová, Hana (referee)
Recently, nanotechnology has gained a lot of interest and the likelihood of emission of nanomaterials into the enviromment increases as well as the risk of its adverse effects. There is very little information about the behaviour and effects of nanomaterials in the environment, but so far the studies indicate an increasing rate of adverse effects of nanomaterials with decreasing particle size. The aim of this work was to determine the toxicity of nanoparticles of CeO2 of the size of 47,7 nm and 2,1 nm on a green, freshwater algae Desmodesmus subspicatus. Furthermore, the influence of surfactant addition on the toxicity of both substances was evaluated. The results showed that the particle of 2,1 nm showed a higher toxicity than the bigger particles, which is consistent with that was found in the literature. After addition of surfactant, an increase of toxicity was observed increase for both forms
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