|
|
Composite medical textile - preparation, characterization, application
Bušinová, Zuzana ; Ing. Vítězslav Zilvar. (referee) ; Krouská, Jitka (advisor)
This bachelor thesis deals with the setting time of the Safix plus gypsum bandage from the Hartmann - Rico a.s. company. The aim of the work is to improve the quality control process of this product and developing a simple robust method for determining the quality control of the Safix plus plaster cast. Two methods and instruments were chosen for the measurement, the Vicat instrument and a rheometer. Vicat's device works on the principle of measuring the depth of penetration of the penetrating body into the sample from a constant height. A rheometer is used to measure rheological properties of the sample, such as viscosity. For both of these methods, it was necessary to prepare the gypsum powder from the gauze. By measuring on the rheometer, the setting time was determined to be 2.4 ± 0.1 minutes and by measuring on the Vicat instrument the observable setting time was determined to be 3.1 ± 0.2 minutes and the complete solidification time to be 6.0 ± 0.4 minutes. Due to the purchase price of the rheometer and in combination with the intended purpose (i.e., product quality control in the commercial sector), the use of a Vicat device appears to be a more suitable option, not only due to the considerably lower purchase price, but also due to simplicity of measurement.
|
|
|
Use of microcalorimetric techniques in the study of stress adaptation of microorganisms
Korfantová, Stanislava ; Slaninová, Eva (referee) ; Krouská, Jitka (advisor)
This bachelor thesis uses microcalorimetric techniques to study stress adaptation of wild strain of H. halophila and H. halophila strain adapted to lower salinity of medium in the environment of levulinic acid, which occurs naturally in hydrolysates of lignocellulosic materials. These can serve as inexpensive substrates on which H. halophila is capable of producing polyhydroxybutyrate. Microcalorimetric measurements showed that the wild-type H. halophila strain could adapt to levulinic acid to a concentration of 5 g/l. The adapted strain, which was assumed to have poorer stress management based on lower PHB yields, could adapt to all observed concentrations. The results were compared with a conventional method that confirmed the results of microcalorimetry. Microcalorimetry has been evaluated as a universal and susceptible method that is suitable for studying the metabolic activity of microorganisms. To better interpret the obtained microcalorimetric results, it is necessary to supplement the technique with information from other analytical techniques. The bachelor thesis uses spectrophotometric and gravimetric determination and gas chromatography with a flame ionization detector to characterize the wild and adapted strain before monitoring the adaptation to levulinic acid. The techniques offered enriching information to supplement the microcalorimetry outputs.
|
|
|
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.
|
|
|
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.
|
|
|
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.
|
|
|
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.
|
|
|
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.
|
|
|
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.
|
|
|
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.
|
|
|
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.
|
guest ::
RSS feed.