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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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Graphene oxide (GO) and its ability to detect and capture bacteria and viruses
Roupcová, Petra ; Klouda, Karel ; Kleinová, Sabina
In recent years, advances in nanomaterials research have led to an increase in their various applications in almost every conceivable field, from electrodes to membranes to sports equipment and clothing. Graphene, graphene oxide (GO) and reduced graphene oxide (rGO) are becoming increasingly popular, mainly due to their extraordinary properties and structure. This paper summarizes the potential use of graphene oxide for trapping bacteria and viruses and other potential applications, especially in light of the ongoing coronavirus crisis.
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Nanofibres as part of respiratory protective devices, but also as a potential source of nano and microplastics to the environment
Klouda, Karel ; Bátrlová, Kateřina ; Roupcová, Petra
Increased production of nanofibers (nanotextiles) is causing a global pandemic for their application in protective equipment such as respirators, face shields, nanocoatings, nano knitwear. In essence, the materials from which these protective devices are made are a combination of non-woven fabrics and nanofibers deposited on textiles. The question is to what extent these products will affect the occurrence of nano and microplastics in the environment. This paper focuses on the acquisition and identification of sources of plastic nanoparticles (nanofibers) that are released into the environment. The following possible sources are compared: during the preparation of nanofibres by electrostatic softening; during the processing of nanofibre textiles into products such as respirators, nano-muffs; during mechanical stresses on nanofibre textiles, friction, abrasion; when used respirators, muffs are thrown on the soil grass, in puddles, in water, etc.
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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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Regulation of pre-mRNA splicing in S. cerevisiae: where RNA cooperates with proteins.
Gahura, Ondřej ; Půta, František (advisor) ; Pospíšek, Martin (referee) ; Staněk, David (referee)
Ondřej Gahura, PhD Thesis 2011 Regulation of pre-mRNA splicing in S. cerevisiae: where RNA cooperates with proteins Abstract Removal of introns from protein coding transcripts occurs in two splicing reactions catalyzed by a large nuclear complex, spliceosome. The spliceosome is an extremely intricate and dynamic machine, wherein contributions of small RNA molecules and multiple proteins are coordinated to meet the requirements of absolute precision and high flexibility. For an intimate understanding of pre-mRNA splicing, it is necessary to unravel roles of individual components and to dissect the partial mechanisms. In the first part of this work, we describe the role of the Prp45 splicing factor in Saccharomyces cerevisiae. Mapping of genetic interactions of a conditionally lethal allele prp45(1-169) suggests a relationship of Prp45 to the NTC complex and to the second transesterification. Two-hybrid assay and purification of spliceosomal complexes reveal a contribution of the Prp45 C-terminus in the Prp22 helicase recruitment and/or regulation. Numerous experiments with reporter substrates document the need of Prp45 for the efficient splicing of a specific subset of introns. Our observations suggest that the function of Prp45 in splicing is conserved in evolution. The second part is devoted to the role of...
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Study on dynamics of spinning apparatus of some wolf spiders (Araneae: Lycosidae) during their life cycle
Dolejš, Petr ; Smrž, Jaroslav (advisor) ; Žďárek, Jan (referee) ; Hajer, Jaromír (referee)
Current knowledge of the spinning apparatus comes namely from studies on orb web spiders and their relatives, whereas that of wolf spiders were more or less neglected. Therefore, developmental changes of the spinning apparatus of four wolf spiders were studied throughout their life cycles. Each of these lycosids possesses stenochronous life cycle with similar number of instars (7-10) but of different length (1-3 years). There is only one period of reproduction in spring/summer in all four species. Sperms are being formed just after the final moult; diplotene in some species is peculiar. The courtship behaviour reflects the microhabitat occupied by the concrete spider species; the copulations are species specific. Ontogeny of the spinning apparatus of developing spiderlings was observed: The spinning apparatus initiate its function in the first instar. Secondary ampullate, all piriform and all but four aciniform glands are tartipore-accommodated; they do not moult in situ. The tartipores, vestigial structures corresponding to spigots of the previous instar, appear on the spinning field starting with the second instar. Tartipore-accommodated glands play roles also during proecdysis and their evolution corresponds with the way how do the spiders secure themselves when moulting. Hence, the not yet...
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"We drag the cart of capitalism on and on": Ethnography of factory production
Virtová, Tereza ; Stöckelová, Tereza (advisor) ; Abu Ghosh, Yasar (referee)
This thesis presents the main results of a five-month ethnographic research project in a global factory in the Czech Republic. It is focused on three topics. Due to a number of ethical dilemmas that accompanied the research, the first part examines ethics in anthropology, both the instruments of the institutionalization of professional ethics and "ethics in practice". As a strategy for dealing with ethical dilemmas the thesis aims at a reflexive approach, as proposed by Guillemin and Gillam (2004) not only to ensure rigor in research methodology, but also as a form of "morally adequate research work". The second research focus is the production line. The line makes sense - that is, produces stuff - only when people and machines interconnect. Symmetrical analysis juxtaposes humans and machines and explores the dynamics of agency as it shifts the borders between people and machines and the characteristics that each takes from the other. The last part of the thesis presents the factory as an actor in the labor market. Through the analysis of economic and organizational factors as well as workers" stories and interpretations and regional authorities" accounts, the final part tries to explain the perception of the factory as a stable and relatively solid employer. Keywords: global factory, ethics,...
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