Ústav fyzikální a spotřební chemie
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- ItemPlasma treated water as a tool for sustainable applications(Czech Technical University in Prague, 2024-05-29) Kozáková, Zdenka; Čechová, Ludmila; Šťastná, Kateřina; Šindelková, Kateřina; Korečková, Svatava; Krčma, FrantišekPlasma treated water was prepared by non-thermal plasma systems using plasma interaction above or inside liquid or in a remote bubbling regime. Plasma treated water prepared from distilled, tap or water solutions was characterised by physical properties (pH, conductivity) and colorimetric determination of stable chemical species (hydrogen peroxide, nitrites, and nitrates). Its quality was evaluated with respect to its possible utilization in sustainable agriculture and medicine applications.
- ItemAntimycotic effects of the plasma gun on the yeast Candida glabrata tested on various surfaces(WILEY-V C H VERLAG GMBH, 2024-07-04) Trebulová, Kristína; Orel, Inna; Pouvesle, Jean Michel; Robert, Eric; Rouillard, Amaury; Stancampiano, Augusto; Hrudka, Jan; Menčík, Přemysl; Kozáková, Zdenka; Měšťánková, Zuzana; Kužmová, Darina; Paličková, Ivana; Čížek, Alois; Krčma, FrantišekThis work focuses on the antimycotic effects of the plasma gun as a potential tool for the treatment of superficial infections. Candida glabrata was chosen as a model microorganism. The preliminary tests have been done on the agar plates to establish the basic plasma parameters. To render this research more appropriate to the real application, more complex inoculation substrates, pork skin and 3D-printed models of the dog ear canal have been used. The results of this work confirm the high efficiency of cold plasma in the inhibition of yeasts on different surfaces and will lead to further experiments.
- ItemApplication of low temperature plasmas for restoration/conservation of archaeological objects(IOP Publishing, 2014-12-18) Krčma, František; Janů, Lucie; Miková, Petra; Graham, William; Grossmannová, Hana; Holíková, Lenka; Horák, Jakub; Janová, Drahomíra; Kelsey, Colin Patrick; Kozáková, Zdenka; Mazánková, Věra; Procházka, Michal; Přikryl, Radek; Řádková, Lucie; Sázavská, Věra; Vašíček, Michal; Veverková, Radka; Zmrzlý, MartinThe low temperature low-pressure hydrogen based plasmas were used to study the influence of processes and discharge conditions on corrosion removal. The capacitive coupled RF discharge in the continuous or pulsed regime was used at operating pressure of 100-200 Pa. Plasma treatment was monitored by optical emission spectroscopy. To be able to study influence of various process parameters, the model corroded samples with and without sandy incrustation were prepared. The SEM-EDX analyzes were carried out to verify corrosion removal efficiency. Experimental conditions were optimized for the selected most frequent materials of original metallic archaeological objects (iron, bronze, copper, and brass). A special focus was kept for the samples temperature because it was necessary to avoid any metallographic changes in the material structure. The low pressure hydrogen plasma is not applicable for objects with a very broken structure or for non-metallic objects due to the non-uniform heat stress. Due to this fact, the new developed plasmas generated in liquids were applied on selected glass materials. The original archaeological objects were used in this case because it was very complicated to prepare a uniform artificial corrosion layer at laboratory conditions.
- ItemAtmospheric Pressure Microwave Plasma Jet for Organic Thin Film Deposition(MDPI, 2020-02-06) Narimisa, Mehrnoush; Krčma, František; Onyshchenko, Yuliia; Kozáková, Zdenka; Morent, Rino; De Geyter, NathalieIn this work, the potential of a microwave (MW)induced atmospheric pressure plasma jet (APPJ) in film deposition of styrene and methyl methacrylate (MMA) precursors is investigated. Plasma properties during the deposition and resultant coating characteristics are studied. Optical emission spectroscopy (OES) results indicate a higher degree of monomer dissociation in the APPJ with increasing power and a carrier gas flow rate of up to 250 standard cubic centimeters per minute (sccm). Computational fluid dynamic (CFD) simulations demonstrate nonuniform monomer distribution near the substrate and the dependency of the deposition area on the monomercontaining gas flow rate. A nonhomogeneous surface morphology and topography of the deposited coatings is also observed using atomic force microscopy (AFM) and SEM. Coating chemical analysis and wettability are studied by XPS and water contact angle (WCA), respectively. A lower monomer flow rate was found to result in a higher C–O/C–C ratio and a higher wettability of the deposited coatings.
- ItemOn the bioprotective effects of 3-hydroxybutyrate: Thermodynamic study of binary 3HB-water systems(Biophysical Society, 2023-02-07) Slaninová, Eva; Obruča, Stanislav; Kocherbitov, Vitaly; Sedláček, PetrThe comprehensive study of the phase behavior of sodium 3-hydroxybutyrate (Na3HB) in aqueous mixtures has shed new light on the recently revealed bioprotective role of this compound in poly(3-hydroxybutyrate)-accumulating microorganisms. The outstandingly hydrophilic nature of 3HB is shown, which is comparable with, but in some perspectives (solubility, water activity decreased in solution) even better than some well-recognized compatible solutes such as trehalose. This is of crucial importance also from the view of its potential application in the technological fields in which stabilization of biological molecules is required (e.g., cryopreservation, food preservation, cosmetics). The study also revealed that 3HB can form, depending on the conditions, at least two different crystalline forms: anhydrous crystal and crystalline dihydrates.