Fakulta chemická

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    Hydrothermal synthesis and characterization of calcium phosphate-based coatings on AZ31 magnesium alloy
    (Sciendo, 2023-05-01) Horáková, Lenka; Doskočil, Leoš; Wasserbauer, Jaromír; Buchtík, Martin
    This study aims to analyze the influence of process parameters used for hydrothermal synthesis of CaP coatings on their properties and to improve their corrosion resistance and biocompatibility compared to the substrat AZ31. The parameters monitored were deposition time, pH of the reaction mixture, and concentration of precursors in the reaction mixture. For the deposited CaP coatings on AZ31 magnesium alloy, the surface morphology and the number of structural defects were evaluated using scanning electron microscopy. Electrochemical corrosion properties were evaluated using polarization techniques in Hank’s solution. The results showed that the best properties were obtained for the sample prepared in a reaction mixture at 120 °C, pH 5 for a deposition time of 120 min, when the concentration of precursors in the reaction mixture was 0.30 mol/l Ca(NO3)2·4H2O and 0.28 mol/l NH4H2PO4. Under these conditions, the best electrochemical corrosion properties were achieved.
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    Degradation of P(3HB-co-4HB) Films in Simulated Body Fluids
    (MDPI, 2022-05-13) Vodička, Juraj; Wikarská, Monika; Trudičová, Monika; Juglová, Zuzana; Pospíšilová, Aneta; Kalina, Michal; Slaninová, Eva; Obruča, Stanislav; Sedláček, Petr
    A novel model of biodegradable PHA copolymer films preparation was applied to evaluate the biodegradability of various PHA copolymers and to discuss its biomedical applicability. In this study, we illustrate the potential biomaterial degradation rate affectability by manipulation of monomer composition via controlling the biosynthetic strategies. Within the experimental investigation, we have prepared two different copolymers of 3-hydroxybutyrate and 4-hydroxybutyrate-P(3HB-co-36 mol.% 4HB) and P(3HB-co-66 mol.% 4HB), by cultivating the thermophilic bacterial strain Aneurinibacillus sp. H1 and further investigated its degradability in simulated body fluids (SBFs). Both copolymers revealed faster weight reduction in synthetic gastric juice (SGJ) and artificial colonic fluid (ACF) than simple homopolymer P3HB. In addition, degradation mechanisms differed across tested polymers, according to SEM micrographs. While incubated in SGJ, samples were fragmented due to fast hydrolysis sourcing from substantially low pH, which suggest abiotic degradation as the major degradation mechanism. On the contrary, ACF incubation indicated obvious enzymatic hydrolysis. Further, no cytotoxicity of the waste fluids was observed on CaCO-2 cell line. Based on these results in combination with high production flexibility, we suggest P(3HB-co-4HB) copolymers produced by Aneurinibacillus sp. H1 as being very auspicious polymers for intestinal in vivo treatments.
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    Effect of alkali salts on the hydration process of belite clinker
    (MDPI, 2022-05-10) Hrubá, Valeriia; Kalina, Lukáš; Sedlačík, Martin; Cába, Vladislav; Másilko, Jiří; Novotný, Radoslav
    Belite-rich cement represents one of the low carbon footprint binders. Nevertheless, its use is ac-companied by a low initial rate of hydration. This can be partially eliminated by the grinding to high specific surfaces or by the addition of admixtures (mineralizators or activators). The influence of alkaline activators: CaSO4, Na2SO4 and Na2CO3 (in the amount of 5wt.% related to the clinker weight) on hydration course as well as the quantity of hydration products of belite-rich cements were investigated within this paper. Belite-rich clinker was laboratory synthetized and grinded together with activators to prepare various belite-rich cements. Next, the hydration kinetics and the hydrated phase assemblage were investigated using the isothermal calorimetry, X-ray powder diffraction and thermogravimetric and differential thermal analyses. The use of selected admixtures allows to obtain belite-rich cements with the higher hydraulic activity in initial times.
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    G-quadruplexes in H1N1 influenza genomes
    (Springer Nature, 2021-01-24) Brázda, Václav; Porubiaková, Otília; Cantara, Alessio; Bohálová, Natália; Coufal, Jan; Bartas, Martin; Fojta, Miroslav; Mergny, Jean-Louis
    Background: Influenza viruses are dangerous pathogens. Seventy-Seven genomes of recently emerged genotype 4 reassortant Eurasian avian-like H1N1 virus (G4-EA-H1N1) are currently available. We investigated the presence and variation of potential G-quadruplex forming sequences (PQS), which can serve as targets for antiviral treatment. Results: PQS were identified in all 77 genomes. The total number of PQS in G4-EA-H1N1 genomes was 571. Interestingly, the number of PQS per genome in individual close relative viruses varied from 4 to 12. PQS were not randomly distributed in the 8 segments of the G4-EA-H1N1 genome, the highest frequency of PQS being found in the NP segment (1.39 per 1000 nt), which is considered a potential target for antiviral therapy. In contrast, no PQS was found in the NS segment. Analyses of variability pointed the importance of some PQS; even if genome variation of influenza virus is extreme, the PQS with the highest G4Hunter score is the most conserved in all tested genomes. G-quadruplex formation in vitro was experimentally confirmed using spectroscopic methods. Conclusions: The results presented here hint several G-quadruplex-forming sequences in G4-EA-H1N1 genomes, that could provide good therapeutic targets.
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    The Interaction of Microplastics and Microbioplastics with Soil and a Comparison of Their Potential to Spread Pathogens
    (MDPI, 2024-06-18) Trojan, Marek; Koutný, Marek; Brtnický, Martin; Holátko, Jiří; Zlámalová Gargošová, Helena; Fojt, Jakub; Procházková, Petra; Kalčíková, Gabriela; Kučerík, Jiří
    Microplastics contribute to various environmental issues and serve as carriers for a wide range of toxic compounds such as pesticides, pharmaceuticals, and metal ions. Consequently, there is a gradual shift towards replacing them with biodegradable plastics (bioplastics). However, biodegradable plastics require specific conditions for complete biodegradation, and their biodeterioration often leads to the rapid production of smaller fragments, known as microbioplastics. In this review, we summarize selected issues related to the impact of plastic particles on soil properties and the soil microbiome. Findings from numerous studies indicate that both microplastics and microbioplastics induce adverse changes in soil microbiology, potentially increasing the abundance of soil-borne pathogens. Based on these observations, we argue that plastic particles could serve as carriers for colonies of soil-borne pathogens. Furthermore, the use of bioplastics may exacerbate this issue due to their easier and faster formation, increased support for biofilms, and more pronounced adverse effects on soil biota. However, further research is necessary to either substantiate or refute this perspective.