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Males-females differences in the spectrum of chromosomal aberrations in the group of nanocomposites production workers
Rössnerová, Andrea ; Pelcová, D. ; Ždímal, Vladimír ; Elzeinova, Fatima ; Margaryan, Hasmik ; Chvojková, Irena ; Topinka, Jan ; Schwarz, Jaroslav ; Ondráček, Jakub ; Koštejn, Martin ; Komarc, M. ; Vlčková, Š. ; Fenclová, Z. ; Lischková, L. ; Dvořáčková, Š. ; Rössner ml., Pavel
An increase in the use of nanomaterials (NM) has been witnessed in many areas of human life. Therefore, assessment of genotoxicity of NM and nanoparticles (NP) is one of the main objectives of genetic toxicology. Despite this fact, human cytogenetic studies following the exposure to NP are still rare. Moreover, no relevant information on possible differences in sensitivity to NP related to gender is available.\n\nIn this study we periodically (in September 2016, 2017 and 2018; pre-shift and post-shift each year) analyzed a group of workers (both genders), working long time in nanocomposites research, and matched controls. Aerosol exposure monitoring of particulate matter including nano-sized fractions was carried out during working shift. Micronucleus assay using Human Pan Centromeric probes, was applied to distinguish, besides the frequency of total MN in binucleated cells (BNC), also other types of chromosomal damage (losses and breaks). Moreover, whole-chromosome painting (WCP) for autosome #1 and both gonosomes (X and Y) were applied in third sampling period (2018) with the aim to identify the particular structural and numerical chromosomal aberrations.\n\nObtained results showed: (i) differences in the risk of exposure to NP related to individual working processes (welding, smelting and machining); (ii) differences in chemical composition of nano-fraction; (iii) no effect of chronic exposure of NP (total MN) opposite to significant effect of acute exposure; (iv) gender-related DNA damage differences (females seem to be more sensitive to chromosomal losses). Additional data from WCP suggested increased frequency of numerical aberrations in gonosomes.
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Microplastics and their removal from water using sorbents.
Spáčilová, Markéta ; Dytrych, Pavel ; Koštejn, Martin ; Fajgar, Radek ; Šolcová, Olga
The increased occurrence of contaminants in water sources, whether microplastics or other organic contaminants, is currently an ever-increasing environmental problem. This issue is closely related to the mapping of their occurrence in the aquatic environment, as well as to possible ways to eliminate them. The work first characterized the characterization of prepared microplastic particles of the five most commonly used plastics (polyethylene, polyamide, polytetrafluoroethylene, polyethylene glycol terephthalate and polystyrene) using scanning electron microscopy (SEM), Raman spectroscopy and infrared spectroscopy (IR). These microplastic particles were used to prepare simulated microplastic contaminated waters. A methodology for determining the number of microplast particles contained was developed on these water samples. Furthermore, the method of their removal from samples with simulated contamination using functional sorbents was tested. Sorbents based on natural bentonites and zeolites were mainly used. It has been confirmed that the effectiveness of these materials depends not only on their composition and textural properties, but can also be increased by modifying them.\n
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Co-Mn-Al mixed oxides promoted for direct NO decomposition: preparation and properties.
Jirátová, Květa ; Pacultová, K. ; Balabánová, Jana ; Karásková, K. ; Klegová, A. ; Bílková, T. ; Jandová, Věra ; Koštejn, Martin ; Martaus, A. ; Kotarba, A. ; Obalová, L.
The catalysts investigated in this work were prepared by co-precipitation of nitrates with aqueous K2CO3/KOH solution, followed by washing the precipitates to varying degrees of potassium content and calcining the precursors at 500 °C for 4 h. Mn-Al potassium salt followed by calcination at 500 °C. Before the catalytic reaction, they were calcined at 700 °C. The catalysts and their precursors were characterized by the following measurement techniques: ICP, DTG, XRD, N2 physisorption, FTIR, H2-TPR, CO2-TPD, XPS, and thermal alkali metal desorption (SR-TAD).\n\n
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Co-Mn Mixed Oxides Preared by Magnetron Sputtering on Meshes as Catalysts for Oxidation of Organic Compounds.
Jirátová, Květa ; Perekrestov, Roman ; Dvořáková, M. ; Balabánová, Jana ; Koštejn, Martin ; Topka, Pavel ; Kšírová, Petra ; Čada, Martin ; Hubička, Zdeněk ; Kovanda, F.
The catalysts with various Mn content were examined by XRD, SEM, FUR. XPS, and Ih-TPR. tested in the gas-phase oxidation of model organic compound (ethanol) and compared with pelletized commercial Co-Mn- Al mixed oxide catalyst (Astin 2-100, Czech Republic, Co:Mn:Al molar ratio of 4:1:1 ).
Fulltext: content.csg -  DOC
Plný tet: 00206B6C274C191104151706 - DOC
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The Novel Preparation of Hydrotreating Catalysts Using Machanochemical Activation of Aluminum Nitrate and NiMo Complexes.
Kaluža, Luděk ; Jirátová, Květa ; Tyuliev, G. ; Gulková, Daniela ; Balabánová, Jana ; Palcheva, R. ; Koštejn, Martin ; Spojakina, A.
The novel Al2O3 synthesis by mechanochemical activation of aluminum nitrate hydrate was applied to prepare hydrodesulfurization (HDS) NiMo catalysts. Impregnation techniques using the complex made by dissolution of nitrilotriacetic acid (NTA), ammonium heptamolybdate and nickel nitrate and the Anderson-type heteropolyoxymolybdate ((NH4)4Ni(OH)6Mo6O18) complex were compared with conventional impregnation using subsequent deposition of ammonium heptamolybdate (first) and nickel nitrate (second) with calcination in between. Properties of the support and HDS catalysts were studied by N2 physisorption, Raman spectroscopy, H2 temperature-programmed reduction (H2-TPR), O2 chemisorption and X-ray photoelectron spectroscopy (XPS).
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Hydrodesulfurization NiMo Catalysts over Mechanochemically Prepared Gamma-Alumina.
Kaluža, Luděk ; Jirátová, Květa ; Tyuliev, G. ; Palcheva, R. ; Koštejn, Martin ; Spojakina, A.
The aim of the present work is to explore optimum preparation route of NiMo catalysts for the novel mechanochemically prepared Al2O3 in order to achieve high HDS activity. Specifically, the goals are: i) to up-scale the support synthesis to provide sufficient amount ofAl2O3, ii) to deposit NiMo from solutions of highly soluble precursors by conventional impregnation techniques (I), i.e. sequential impregnation using Mo (first) and Ni (second), and by co-impregnation (Ni+Mo together), i.e. using chelating agent NTA or nickel heteropolyoxomolybdate (HPO), iii) to deposit NiMo from solutions ofslightly soluble precursors by slurry impregnation (SI).\n
Fulltext: content.csg - PDF
Plný tet: SKMBT_C22018100509420 - PDF
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Preparation of Magnesium Silicide from Recycled Materials for Energy Storage.
Bumba, Jakub ; Dytrych, Pavel ; Šolcová, Olga ; Koštejn, Martin ; Fajgar, Radek ; Maléterová, Ywetta ; Kaštánek, František
Recycling technologies help to save energy, materials and environment. This is the main reason of their popularity. The recovery of semiconductors and metals depends on recycling treatment. A new multi-step technology, which enables to obtain pure silicon and hydrogen from waste materials,is reported in this study. The only by-product is magnesium phosphate, which is a desired fertilizer. Magnesium silicide was successfully prepared from milled silicon photovoltaic (PV) panels and milled Mg obtained from the scrap. The formed magnesium silicide was then hydrolysed by phosphoric acid to form a mixture of silanes. Gaseous products (silanes) were separated by cooling below their boiling temperature by liquid nitrogen and then thermally decomposed by a hot wire, e.g. Pt.This treatment leads to pure silicon and hydrogen release. In this study a deep-in characterization by various methods spectroscopy, Scanning Electron Microscopy (SEM) with Energy Dispersive X- Ray spectroscopy (EDX), etc.) of prepared samples was also done to explain the individual influences, e.g. reaction temperature and atmosphere.
Fulltext: content.csg - PDF
Plný tet: SKMBT_C22016111814301 - PDF
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