|
|
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
|
|
|
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...
|
|
|
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.
|
|
|
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...
|
|
|
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...
|
|
|
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
|
|
|
Nanotechnology: Implementation of contemporary progress into science education at secondary school and in education of future chemistry teachers
Hájková, Zdeňka ; Šmejkal, Petr (advisor) ; Procházka, Marek (referee)
This rigorous thesis is focused on possible ways how to implement interesting and important findings from the field called "nanoworld" into the curriculum of science subjects at secondary school. For this purpose the following materials were prepared: an educational text (which also serves as a theoretical base that summarises basic information about nanotechnology and nanoscience), a multimedia Power- Point presentation, a concept of a project "When you say NANOTECHNOLOGY...", a concept of an excursion, motivational and developing interdisciplinary tasks with the theme "nano", two tests aimed at nanotechnology and advanced microscopy techniques (electron microscopy and scanning probe microscopy) and simply demonstrations. The proposed project was tested at two grammar schools in Prague. The excursion was also realized and evaluated. Both the project as well as the excursion met with an average response from students. This thesis is accompanied by a CD with the presentation and print versions of the project, pre-test, post-test and worksheets for the excursion, interdisciplinary tasks and test items. In addition, the CD contains photos and students work from the realization of the pro- ject. Furthermore, this thesis includes the questionnaire "Teach (learn) about "nano" - YES or NO?" (with...
|
|
|
Nanotechnology utilization in nuclear industry and research
Skalička, Jiří ; Štefánik, Milan (referee) ; Katovský, Karel (advisor)
This thesis introduces reader to current knowledge of nanomaterials and their usage. It summarises production methods and usage of different materials in nuclear power plants, nuclear research and nuclear medicine. Theoretical part of this thesis is dedicated to possible usage of carbon nanotubes for neutron beam collimation and guides. In experimental part different materials were tested in measuring box connected to horizontal radial channel of VR-1 nuclear reactor and their influence on neutron flux was measured. Tested samples were non-oriented carbon nanotubes, carbon nanofibers, alumina nanowires, oriented carbon nanotubes with several angles of rotation and these samples were compared with results of graphite.
|
|
|
Hygiene Problems Associated with Nanoparticles
LHOTSKÁ, Veronika
Nanotechnology is a rapidly developing branch and its popularity quickly ratchets up. Currently, nanomaterials form parts of a range of products of daily consumption. They are put into foodstuffs, cosmetics, and are used in medical science and technical branches. Nanomaterials are being considerably popularized which has helped them to penetrate into the lay public. The information from media are mostly given in a non-professional way and misrepresented, and taken from the context, they have sensationalist and advertising character. My thesis summarizes the basic finding about nanomaterials, their usage in practice and their effect on man´s health. Two hypotheses were fixed: The usage of nanomaterials is medially popularized but the non-professional public is not informed correctly about it. The lay public is not aware of possible negative effects of nanomaterials on man´s health.
|
|
| |
guest ::
