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Hyaluronan-albumin complexes behavior at physiological conditions.
Šuleková, Nikola ; Kratochvílová, Romana (referee) ; Chytil, Martin (advisor)
This thesis discusses the interactions of low molecular weight and high molecular weight hyaluronic acid (HA) with bovine serum albumin (BSA) in physiological environment. It is based on previous work dealing with HA and amphiphilic substances which are currently widely studied for its potential applications in medicine. Solutions of HA with fixed concentration and albumin of concentration in the range of 0,25 – 20 g/l were prepared at room temperature and at 37°C and examined by rheometry and turbidimetry. It was observed that the maximum absorbance increases with increasing concentration of BSA and does not show variations depending on the temperature of preparation. On the other hand, the turbidity occurs in significant differences between the samples prepared at ambient temperature and at 37°C. Overall, the turbidity increases with the concentration of BSA. Rasing the temperature caused the increase in viscosity of the samples, which was further varied with the concentration of BSA. Mixed solutions of high molecular weight HA and BSA showed the highest turbidity, maximum absorbance and viscosity, while the solutions of BSA showed the lowest values. The results indicate formation of complexes, of which properties are dependent on BSA concentration, the molecular weight of HA, and the temperature of preparation.
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Changes in some physical properties of the aqueous suspension of corundum powder during ultrafine grinding
Šuleková, Nikola ; Šiler, Pavel (referee) ; Svěrák, Tomáš (advisor)
This thesis is focused on the study of changes in properties of the aqueous suspensions of corundum during ultrafine grinding without and with the addition of grinding activator. Such studies are an important step in optimizing the grinding process properly, because by measuring physical properties of a particulate substance, it is easy to determine the actual fineness of the ground substance and its quality for further processing. For the measurement of granulometry, zeta potential, rheological behavior and turbidity, corundum suspensions in distilled water were prepared in a 1:5 ratio without the addition of grinding activator and with the addition of triethanolamine (TEA), by using a planetary mill. The suspensions showed pseudoplastic behavior and the zeta potential of all samples ranged between -30 and 30 mV, thus the suspensions were rather unstable. During the grinding, the viscosity and turbidity of the samples increased. TEA was not proved to be a suitable activator for wet milling of corundum because of higher degree of fineness achieved during milling without an activator.
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High performace cement composites with increased abrasion resistance
Baranov, Dmitry ; Šuleková, Nikola (referee) ; Novotný, Radoslav (advisor)
The bachelor thesis deals with the effect of addition of potassium hydroxide solutions of different concentrations to HPC composites. The study focused mainly on parameters important for the abrasion of the composite such as surface hardness, which was measured in two ways. The first is by using of a manual hardness tester, the second is by a notching method through a drill with a tungsten carbide crown. The samples with the highest concentration of potassium hydroxide had the best results. It was assumed that the cause could be a very thin (400 1000 nm) dense layer on the surface with a predominant content of sulfur and potassium compounds, which was shown on an electron microscope. In addition to the hardness of the surface, other mechanical properties important for cements were monitored. Samples with different KOH concentration were tested for compressive and flexural strength.
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Changes in some physical properties of the aqueous suspension of corundum powder during ultrafine grinding
Šuleková, Nikola ; Šiler, Pavel (referee) ; Svěrák, Tomáš (advisor)
This thesis is focused on the study of changes in properties of the aqueous suspensions of corundum during ultrafine grinding without and with the addition of grinding activator. Such studies are an important step in optimizing the grinding process properly, because by measuring physical properties of a particulate substance, it is easy to determine the actual fineness of the ground substance and its quality for further processing. For the measurement of granulometry, zeta potential, rheological behavior and turbidity, corundum suspensions in distilled water were prepared in a 1:5 ratio without the addition of grinding activator and with the addition of triethanolamine (TEA), by using a planetary mill. The suspensions showed pseudoplastic behavior and the zeta potential of all samples ranged between -30 and 30 mV, thus the suspensions were rather unstable. During the grinding, the viscosity and turbidity of the samples increased. TEA was not proved to be a suitable activator for wet milling of corundum because of higher degree of fineness achieved during milling without an activator.
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Hyaluronan-albumin complexes behavior at physiological conditions.
Šuleková, Nikola ; Kratochvílová, Romana (referee) ; Chytil, Martin (advisor)
This thesis discusses the interactions of low molecular weight and high molecular weight hyaluronic acid (HA) with bovine serum albumin (BSA) in physiological environment. It is based on previous work dealing with HA and amphiphilic substances which are currently widely studied for its potential applications in medicine. Solutions of HA with fixed concentration and albumin of concentration in the range of 0,25 – 20 g/l were prepared at room temperature and at 37°C and examined by rheometry and turbidimetry. It was observed that the maximum absorbance increases with increasing concentration of BSA and does not show variations depending on the temperature of preparation. On the other hand, the turbidity occurs in significant differences between the samples prepared at ambient temperature and at 37°C. Overall, the turbidity increases with the concentration of BSA. Rasing the temperature caused the increase in viscosity of the samples, which was further varied with the concentration of BSA. Mixed solutions of high molecular weight HA and BSA showed the highest turbidity, maximum absorbance and viscosity, while the solutions of BSA showed the lowest values. The results indicate formation of complexes, of which properties are dependent on BSA concentration, the molecular weight of HA, and the temperature of preparation.
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