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Toxicity of microplastics and nanoplastics
Nechvátal, Marek ; Klouda, Karel
The article summarizes the knowledge about the influence of micro and nanoplastics on environmental components. Attention is paid to a complex set of the main toxic effects of plastic particles on selected groups of environmental organisms, especially new information and interactions with living organisms that have the potential to cause ecotoxicological damage.
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Measurement of nanoparticles in 3D printing using FFF/FDM technology
Klouda, Karel ; Kubátová, Hana ; Nechvátal, Marek ; Bátrlová, Kateřina ; Roupcová, Petra
For additive manufacturing, where the material is prepared by depositing thin layers, the simplified term 3D printing is used. This process releases volatile organic compounds and ultrafine particles into the air. A number of measurements have been published on this topic for a given type of printer with a specific type of thermoplastic. The procedure for the measurement of nanoparticle concentrations (10-700 nm) and their mean diameters can be called "field" because it was carried out in a real environment with mass deployment of FFF/FDM 3D printing, with the measuring equipment moving between printers in different areas and activities: in the production of parts to be assembled in the printers; in the production of components for shields during the lockout associated with the covid-19 pandemic; in the creative workshops and laboratories of Průsa Research. The aim of these measurements in real situations was to find measures to reduce the concentration of nanoparticles. The evaluation of the results was carried out in accordance with ISO/TR 27 628 and provided for the design of technological and organisational measures to reduce the concentrations.
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Emission of nanoparticles in the nanotextile industry
Nechvátal, Marek ; Klouda, Karel ; Kubátová, Hana ; Roupcová, Petra ; Bátrlová, Kateřina
We encounter smoke quite regularly in our lives. Smoke consists of gaseous, liquid and solid components that are produced by the combustion/oxidation of fuel. The chemical composition of smoke depends not only on the fuel used but also on a number of other parameters (operation, technology, atmospheric effects). The chemical composition of smoke is therefore variable and cannot be easily characterised. The combustion of wood releases into the atmosphere not only unconsumed air but also wood particles, CO2, methane, volatile organic compounds, trace elements and ultrafine particles. Measurements are published on this topic for a given type of combustion technology with a specific fuel type. The procedure for measuring the concentration of nanoparticles (10-700 nm) in wood smoke and their mean diameters can be called "field". The aim of these measurements in real situations was to find and describe sources of elevated nanoparticle concentrations. Substantial quantitative information on the occurrence of nanoparticles in wood combustion in different types of wood burners was obtained in the field under real climatic conditions, typical of the winter season in Central Europe, when most domestic heating takes place. Thus, wood burning in households in predominantly agricultural areas of the Czech Republic can be considered as a major source of outdoor air pollution, but can also have a significant impact on the deterioration of indoor air quality. At the same time, it can be assumed that the negative impact of nanoparticles on human health in areas polluted by wood smoke is weaker than the impact elsewhere - in industrial, more polluted areas.
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Toxicity of nanotextiles as respirators waste to Daphnia Magna
Slaný, Jan ; Roupcová, Petra ; Pavlovský, Jiří ; Klouda, Karel
In recent years, the prevalence of nanotubes has increased due to the covid-19 disease situation worldwide. Nanotextiles are used in the form of face masks and respirators, which are a source of environmental pollution by nanoparticles. The aim of this paper is to perform ecotoxicological tests according to European standards and Czech legislation. First, non-woven fabrics are briefly described and a small planktonic crustacean (Daphnia magna S.) is introduced. The second part focuses on the experiments themselves and their results. In all cases, the nanotextiles tested did not have a toxic effect on the organisms, but a reaction could be observed. Further tests will be carried out to explain and clarify the effects.
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Titaniun Dioxide - Phosphonate Assemblies as Medical Nanoprobes
Řehoř, Ivan ; Lukeš, Ivan (advisor) ; Lang, Kamil (referee) ; Peters, Joop (referee)
Titanium Dioxide - Phosphonate Assemblies as Medical Nanoprobes Ivan Řehoř PhD. Thesis Abstract: Multimodal imaging-therapeutic nanoprobe TiO2@RhdGd was prepared and successfully used for in- vitro and in-vivo cell tracking as well as for killing of cancer cells in-vitro. TiO2 nanoparticles, 12 nm in diameter, were used as a core for phosphonic acid modified functionalities, responsible for contrast in MRI and optical imaging. The phosphonic acid derivatives, used for surface modification, allows for grafting extraordinarily high loads of irreversibly adsorbed molecules of both types in one step. The prepared probe shows very high 1 H r1 relaxivity value as well as relaxivity density value, both crucial parameters for its use in MRI. The presence of fluorescent dye in its structure allows for its visualization by means of fluorescence microscopy. The applicability of the probe was studied, using three living systems - mesenchymal stem cells, cancer HeLa cells and T-lymphocytes. The probe did not exhibit toxicity in any of these systems and its long time storage in a lysosomal compartment was confirmed. Labeled cells were successfully visualized in-vitro by means of fluorescence microscopy and MRI. Consequent visualization of labeled cells in-vivo by means of fluorescence microscopy was also achieved....
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Fluorescent nanoparticles based on organic chromophores
Čekal, Josef ; Kratochvíl, Matouš (referee) ; Vala, Martin (advisor)
This study aims to create Host-Guest nanoparticle systems exhibiting white light emission (WLE) using organic molecules, achieved through Förster resonance energy transfer (FRET) mechanisms. Substituted stilbene-based compounds were utilized for the preparation of nanoparticle systems, with CA-DPS-V (H2) and CA-DPS-CHO (H1) used as donor/matrix materials, and CA-DPS-DCV (G1) and DPA-DXS-IOO (G2) as acceptor/dopant materials. Three nanoparticle systems were synthesized via nanoprecipitation from common solutions of the compounds in THF: system 1 (H1+G1), which did not achieve WLE, system 2 (H2+G1), and system 3 (H2+G2). Systems 2 and 3 were characterized using fluorescence spectroscopy and FRET parameter calculations. It was found that the Förster distance in system 2 is shorter than in system 3. This variation in Förster distance affects the composition ratios capable of WLE. The closest proximity to the white point (0.33, 0.33) was observed in system 2 at molar ratios of 110:1 (0.32, 0.38) and 164:1 (0.29, 0.32), and in system 3 at ratios of 340:1 (0.34, 0.30) and 476:1 (0.31, 0.28). Thus, the goal of the study was achieved, demonstrating that nanoparticles capable of WLE can be prepared in this manner. However, a drawback of the prepared nanoparticles was their low photostability. Future work could focus on synthesizing more stable nanoparticles from structurally similar compounds. These particles could then be further characterized in terms of structure and other properties for potential applications.
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Plasmonics of non-noble metals
Foltýn, Michael ; Kejík, Lukáš (referee) ; Horák, Michal (advisor)
Tato diplomová práce se zabývá možnostmi použití neušlechtilých kovů v plazmonice. Provedl jsem numerické simulace plazmonických vlastností různých neušlechtilých kovů a na základě dosažených výsledků jsem za materiál studovaný v této práci zvolil bismut. Vyrobil jsem bismutové plazmonické antény za pomoci litografie fokusovaným iontovým svazkem z bismutových polykrystalických vrstev deponovaných magnetronovým naprašováním. Byly vyrobeny tři typy plazmonických antén, tyčinkovité anténky o šířkách 40 a 80 nm a antény typu bowtie s 20 nm širokou mezerou mezi křidélky antény. Studoval jsem plazmonové rezonance v těchto anténách za pomocí spektroskopie energiových ztrát elektronů a shledal jsem bismut dobrým plazmonickým materiálem, který má potenciál stát se levnější alternativou k doposud používanějšímu zlatu, která navíc nabízí širší interval použitelných vlnových délek. Dále jsem syntetizoval monokrystalické bismutové nanočástice za pomocí pyrolýzy octanu bismutitého a otestoval a porovnal různé čistící metody vyžadované pro odstranění vrstev surfaktantů z povrchu vyrobených nanočástic. Studoval jsem plazmonové rezonance těchto nanočástic a našel metodu pro měření energiových ztrát elektronů z nanočástic obklopených tlustou vrstvou kontaminantů.
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Preparation and characterization of epoxy potting resins modified with nanoparticles
Lednický, Jiří ; Polsterová, Helena (referee) ; Chladil, Ladislav (advisor)
This bachelor's thesis focuses on nanocomposites composed of an organic matrix in the form of epoxy resin and TiO2 filler in the anatase crystallographic structure with dimensions in the order of tens of nanometers. The work is aimed at understanding the issue of nanocomposites, summarizing the results of other studies, and especially at the production and characterization of samples with nanoparticles dispersed using a planetary mill. Furthermore, the effect of the used nanoparticles and dispersion in the planetary mill on the dielectric properties of pure epoxy resin was analyzed.
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Deposition of particles released by 3D printing
Niesner, Lukáš ; Elcner, Jakub (referee) ; Bělka, Miloslav (advisor)
This thesis deals with the measurement of particles emitted by a 3D printer in a domestic environment and the subsequent CFD simulation of the deposition of these particles in a realistic model of the human airway. As a result of the work, the total and partial deposition of nanoparticles in the airway model can help to better understand the health risks.
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