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Influence of different forms of titanium dioxide nanoparticles on soil organic matter properties
Miklasová, Marta ; Řezáčová, Veronika (referee) ; Kučerík, Jiří (advisor)
Nanoparticles present potential risk for environmental compartments including soil. Previous works have been focused on negative effects of nanoparticles on soil biota, however studies about the influence of nanoparticles on soil properties are still limited. This thesis investigates an impact of 20 nm titanium dioxide nanoparticles on selected water properties in soil organic matter exposed to air with various relative humidity. Indeed, at 43, 70 and 95 % dominate different water types, i.e. water adsorbed on soil organic matter, water in water molecular bridges and phase water, respectively. Differential scanning calorimetry (DSC) was used in the study. An important finding is that nanoparticles reduce the stability of water molecular bridges under 70% relative air humidity and generally reduce evaporation enthalpy of water, which represents the ability of the soil to retain water. In the next part the influence of nanoparticles on total water in soil was observed. Under low relative humidity, rutile and anatase affected soil in different ways due to their various hydrophilicity. Under higher relative humidity this effect disappeared. In the last part, ice melting and water evaporation enthalpies of nanoparticle solutions were measured to confirm the presumed effect of nanoparticles on water. The ice melting enthalpy of the solutions was higher relatively to pure water, while the evaporation enthalpy showed a reverse trend (decrease). This confirmed the effects of nanoparticles both for pure water and soil water.
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The effect of nanoparticles on functional and regenerative properties of mesenchymal stem cells
Dostálová, Dominika ; Rössner, Pavel (advisor) ; Grobárová, Valéria (referee)
Mesenchymal stem cells (MSCs) represent a type of stem cells, localized in various tissues, where they are involved in the regeneration process. Because of their properties, MSC are tested for cell-based therapy. However, the treatment of injuries is often associated with bacterial infections, which complicate the process of healing. To establish a sterile environment, metallic nanoparticles (NPs) with proven antibacterial properties can be applied, for improving the healing process. Mechanisms of the antibacterial effect of NPs are non-specific and may cause the damage of eukaryotic cells. The aim of this thesis was to evaluate the effect of three antibacterial metallic NPs (silver, copper oxide and titanium dioxide) on the functional and regenerative properties of MSCs. The effect of NPs on the metabolic activity, differentiational potential, expression of genes for immunoregulatory molecules and production of cytokines by MSCs was determined. Additionally, the immunoregulatory properties of MSCs after cultivation with NPs were tested. The results showed that the metabolic activity was reduced in the presence of silver and copper oxide NPs, with the decrease dependent on the type of the tested NPs. The expression of selected immunoregulatory molecules was inhibited and the immunoregulatory...
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Influence of different forms of titanium dioxide nanoparticles on soil organic matter properties
Miklasová, Marta ; Řezáčová, Veronika (referee) ; Kučerík, Jiří (advisor)
Nanoparticles present potential risk for environmental compartments including soil. Previous works have been focused on negative effects of nanoparticles on soil biota, however studies about the influence of nanoparticles on soil properties are still limited. This thesis investigates an impact of 20 nm titanium dioxide nanoparticles on selected water properties in soil organic matter exposed to air with various relative humidity. Indeed, at 43, 70 and 95 % dominate different water types, i.e. water adsorbed on soil organic matter, water in water molecular bridges and phase water, respectively. Differential scanning calorimetry (DSC) was used in the study. An important finding is that nanoparticles reduce the stability of water molecular bridges under 70% relative air humidity and generally reduce evaporation enthalpy of water, which represents the ability of the soil to retain water. In the next part the influence of nanoparticles on total water in soil was observed. Under low relative humidity, rutile and anatase affected soil in different ways due to their various hydrophilicity. Under higher relative humidity this effect disappeared. In the last part, ice melting and water evaporation enthalpies of nanoparticle solutions were measured to confirm the presumed effect of nanoparticles on water. The ice melting enthalpy of the solutions was higher relatively to pure water, while the evaporation enthalpy showed a reverse trend (decrease). This confirmed the effects of nanoparticles both for pure water and soil water.
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