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Phase separation in dilute solutions of polymers and surfactants
Klementová, Tereza ; Krouská, Jitka (referee) ; Mravec, Filip (advisor)
This bachelor's thesis deals with conditions of phase separation in system of polyelectrolyte (sodium hyaluronate) and cationic surfactant (cetyltrimethylammonium bromide). Separated phase was studied by fluorescence measurement with Nile red as a fluorescence probe and there were also specified rheological properties using flow tests and frequency oscillatory tests. Behaviour of separated microgel was also observed in solution of NaCl.
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Influence of metal ions on microorganization of humic substances
Odehnalová, Nikola ; Krouská, Jitka (referee) ; Klučáková, Martina (advisor)
This bachelor thesis is focused on the study of influence of metal ions on microorganization of humic substances. This issue was studied on a sample od fulvic acid. Solution of cocentration 1 g/l was prepared from this sample. This solution was ten titrate with solutions of copper, calcium and magnesium ions. For this purpose, methods of dinamic and electrophoretic light scattering were used. The results obtained by these methods show that the solution of fulvic acid is the most made by associated molecules of fulvic acid. The size of molecules became larger and larger during titrations. Copper was sorpted the most.
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Behaviour of microorganisms using microcalorimetry
Piletskaya, Maryia ; Sedláček, Petr (referee) ; Krouská, Jitka (advisor)
The diploma thesis deals with the study of the behavior of a microorganism with the help of microcalorimetry. The theoretical part of the thesis deals mainly with the characterization of the microorganism Rhodospirillum rubrum selected for experimental work and the application of microcalorimetry in microbiology. The second goal was to screen the growth of the bacterial strain R. rubrum using different substrates, and subsequently, based on experimental results, to select the most suitable substrate, and optimize its concentration and aeration of the medium for the microorganism using microcalorimetry. Hexanoate, malate, acetate and fructose were used to examine the most suitable substrate by microcalorimetry. Another goal was data processing and discussion of the advantages and disadvantages of substrate selection and media aeration with respect to bacterial strain growth. Hexanoate was found to be the best substrate for growth, followed by optimization of the concentration and aeration of the medium. The results of the microcalorimetric measurement were confirmed by spectrophotometric study of the growth curve of the investigated bacteria. The effect of osmotic pressure on bacteria and the dependence of their survival on the amount of polyhydroxyalkanoates (PHA) in the cell were also studied. The amount of PHA in the biomass was determined chromatographically.
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Study of system based on phospholipids for sonographical application.
Überall, Martin ; Krouská, Jitka (referee) ; Mravec, Filip (advisor)
The aim of this thesis was to determine solubilizing capacity of surfactants and phospholipids using the UV-VIS spectrophotometry. The concentrations of solubilized substances within these systems was further determined. From the surfactant group, three representatives were selected, cetyltrimethylammonium bromide (CTAB), sodium dodecylbenzenesulfonate (SDBS) and Triton X-100. From the phospholipid group, lecithin and commercially available SonoVue® were chosen. The solubilizing capacity was determined using hydrophobic solutes Sudan Red G (SRG), Oil Red O (ORO) and 1-naphtol in order to obtain a model system of solubilized drugs or vitamins which are also hydrophobic. The behavior of solutes in surfactants was determined in a moderate polar medium of physiological saline (0.15 M NaCl), the behavior of solutes in lecithin was conversely determined in Mili-Q water medium. The determined concentration of solubilized hydrophobic solutes inside the micelles of surfactants is within the range of tens to hundreds of micromoles per liter. With increasing concentration of surfactant increases the concentration of solubilized solutes. The results obtained in this work can be used for further experiments and research focused on solubilization of drugs in contrast agents used in ultrasonography.
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Interactions and imobilization of pharmaceuticals in soil systems
Šmerdová, Kateřina ; Krouská, Jitka (referee) ; Klučáková, Martina (advisor)
In these days, most non-steroidal anti-inflammatory drugs (NSAIDs), including diclofenac (DK), are considered as environmental contaminants. In this thesis, the sorption and desorption mechanisms of diclofenac in soils with different organic matter content were studied. The pH of the medium and its effect on DK adsorption by Britton – Robinson buffer were also studied. Last but not least, the spontaneous degradation of DK in water under sunshine was observed; depending on similar studies, the photodegradation product has been described. The value of pH and conductivity of all the samples were monitored continuously throughout the experiment. It has been found that the content of soil organic matter has a colossal influence on the drug sorption and desorption. Studied soil with a higher content of organic matter recorded higher adsorption of DK in all monitored koncentration of DK. Different pH values also affected the sorption and desorption of DK. By results, a neutral and alkaline environment supports the adsorption of DK more than an acidic environment. The samples were analyzed by UV-VIS spectrophotometry. Photodegradation of DK in water was successful after 4 months. The degradation product was analyzed by UV-VIS spectrophotometry and FTIR spectrometry. The product of fotodegradation could probably be carbazole derivative.
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Colloid properties of hyaluronane sols
Krouská, Jitka ; Mašek, David (referee) ; Pekař, Miloslav (advisor)
Předmětem této práce bylo popsat agregační vlastnosti kyseliny hyaluronové (HA) a jejích hydrofobně modifikovaných derivátů. Za tímto účelem byly připraveny vodné roztoky kyseliny a dvou derivátů, lišící se stupněm substituce a druhem anorganické soli jako prostředím. Koncentrační řady čisté kyseliny hyaluronové a jejích derivátů byly studovány dvěma metodami, tensiometricky a spektrometricky. Povrchové vlastnosti roztoků byly měřeny s použitím kroužku Du Noüy. Zkoumáno bylo také solubilizační chování ve vodě a v chloridu sodném pomocí dvou sond: Coomassie brilantní modři a sudanu III. Amfifilní deriváty hyaluronanu mohou skutečně tvořit hydrofobní agregáty v roztoku a adsorbovat se na rozhraní vzduch–voda. Tato vlastnost je důležitá v souvislosti s transportními systémy léčiv, protože právě hydrofobní domény agregátů hyaluronanu mohou být použity jako nosiče hydrofobních léčiv. Byly zjištěny kritické agregační koncentrace roztoků derivátů hyaluronanu (tensiometricky a spektrometricky), které odpovídají právě těm koncentracím, při kterých vznikají hydrofobní domény.
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Bigels - Preparation and Characterization
Mušková, Alexandra ; Krouská, Jitka (referee) ; Mravec, Filip (advisor)
This bachelor thesis deals with study of bigels, which are composed of hydrogel and oleogel. The aim of this work is to prepare and characterize bigels. Preparation of hydrogels was based on interaction between hyaluronan and cationic surfactant carbethopendecinium bromide. Oleogels were prepared by mixing a non-ionic surfactant (sorbitan monopalmitate) with sunflower oil. Individual bigels were prepared by mixing the various rations of hydrogel and oleogel, and were characterized using a fluorescence microscope and rheological measurements. Fluorescence observations were done on prepared samples using Nile Red, Perylene, HPTS, ATTO 655 and fluorescein. Rheological experiments show that pure oleogel is the strongest and most solid in comparison with bigels and hydrogels. The greater amount of oleogel in system is, the stronger bigel is.
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Microcalorimetric study of bacterial degradation of oil and its products
Bola, Tomáš ; Benešová, Pavla (referee) ; Krouská, Jitka (advisor)
This bachelor thesis deals with a study of the oil degradation as one of the possible products of petroleum using bacterial stems Pseudomonas Putida a Pseudomonas Chlororaphis. The work is motivated by the research of usability of a method which has not been used for those purposes so far – calorimetric analysis. Using IČ spektrometry (ATR), calorimetry and UV-VIS spectrometry was studied a degree and a character of interactions. Calorimetric analysis showed that the Pseudomonas Putida has bigger abbility of the degradability than Pseudomonas Chlororaphis. There was also detected that the optimal concentration for more effective degradation of oil fuel is 5 g/l and 20 g/l. By measurement of the absorbance deppending on time was verified that the bigger is the concentration of the sample, the higher is the resulted absorbance. Using UV-VIS analysis was determined a quantity of biomass. Using IČ spectometry in the ATR mode (reduced reflectance) was detected structure of the sample and also verified that the bacterial cultures Pseudomonas Putida and Chlororaphis degradated entire amount of petroleum.
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Optimization of condition of procedure of gelation hydroxyethylcellulose using citric acid
Burešová, Natálie ; Krouská, Jitka (referee) ; Hurčíková, Andrea (advisor)
The bachelor thesis dealt with hydrogels, which have the advantage detention large quantities of water, it allows large potential applications, such as in medicine. Hyaluronan and hydroxyethylcellulose were the reactants of crosslinking reaction. Citric acid was crosslinking agent which is nontoxic and inexpensive. Hydroxyethylcellulose and hyaluronan for crosslinking reaction were selected on the finding from available publications. The resulting gels can be used mainly in medicine because they are nontoxic. The main aim of the thesis was optimalizacion process of gelation and hydroxyethylcellulose and finding a suitable gelation process. Selected gelation procedure is applied to a mixture of hydroxyethyl cellulose and hyaluronan in two different weight ratios and hyaluronan. Chemicaly cross-linked were considered samples, which contained hydroxyethylcellulose and then a mixture of hyaluronate and hydroxyethyl cellulose in a weight ratio of 3:7.
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Microcalorimetric and Light Scattering Methods in the Study of Interactions in Biopolymer - Surfactant System
Šojdrová, Kamila ; Mravec, Filip (referee) ; Krouská, Jitka (advisor)
Biopolymer surfactant systems have been studied by using different physico chemical methods. As the biopolymer, it was chosen high (1400–1600 kDa), medium (250–450 kDa) and low (8–15 kDa) molecular weight sodium hyaluronate. Two cationic surfactants – cetyltrimethylammonium bromide (CTAB) and carbethopendecinium bromide (Septonex) were selected to provide polyelectrolyte complexes with oppositely charged hyaluronan. The critical aggregation concentration of the surfactant in the system was monitored by dynamic light scattering (Zetasizer Nano ZS). SEC-MALS method was used for the description of the conformation of sodium hyaluronate of different molecular weights and polyelectrolytes complexes hyaluronan surfactant after reaching the aggregation point. Isothermal titration calorimetry (ITC) was used to determine the critical aggregation concentration of the surfactant by monitoring the thermal changes accompanying the aggregation of the system. It was found out that the increasing molecular weight of hyaluronan in these systems decreases the critical aggregation concentrations and conversely.
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