National Repository of Grey Literature 24 records found  1 - 10nextend  jump to record: Search took 0.01 seconds. 
Characterization catanionic vesicular system by HRUS
Kopřivová, Hana ; Sovová, Šárka (referee) ; Hurčíková, Andrea (advisor)
This bachelor thesis is about catanionic vesicular systems, which could serve as carriers of drugs or genes in the future. These systems are prepared from the cationic surfactants CTAB and DDAC, the anionic surfactant SDS and cholesterol, which serves as a stabilizer. In the experimental part, these vesicles were characterized by high-resolution ultrasonic spectroscopy. The behavior of systems with different percentages of cholesterol was monitored. As next, the temperature properties of the vesicles were studied using temperature scans between 10 °C and 65 °C. The density of the samples was examined by densitometry at temperatures of 25 °C and at a human body temperature of 37 °C.
The characterisation of surfactant CAE
Obršlíková, Monika ; Pekař, Miloslav (referee) ; Hurčíková, Andrea (advisor)
CAE is a cationic surfactant derived from DL-Pyrrolidone Carboxylate, L-Arginine and a fatty acid. This surfactant is mainly used in the cosmetic industry. The exact value of critical micellar concentration of CAE is not known yet. In this research there were examined ultrasonic velocity, density, surface tension and scattered light intensity of CAE solutions in ultra-pure deionized water, in 10mM NaCl, 100mM NaCl and 150mM NaCl.
The intrecations of dextran with surfactant SDS
Marčanová, Milada ; Kalina, Michal (referee) ; Hurčíková, Andrea (advisor)
Before the itself of characterization interactions of dextran with surfactant SDS, there were investigated properties of dextran solution in water and in sodium chloride. At first it was measured by densitometer, where their density and ultrasonic velocity was investigated, depending on concentration and temperature. The ultrasonic velocity was further measured by high resolution ultrasonic spectroscopy. Subsequently the interactions of dextran with surfactant SDS was examined to determine the critical aggregation and critical micelle concentration.
Temperature dependence of carrageenan and hyaluronan solutions
Poledňáková, Halina ; Smilek, Jiří (referee) ; Hurčíková, Andrea (advisor)
This diploma thesis focuses on the study of temperature dependence of -carrageen, hyaluronan of low molecular weight (250–450 kDa) and hyaluronan of high molecular weight (1 500–1 750 kDa) in aqueous solutions. The description of temperature depending changes in properties of these substance is based on rheological method. This work concentrates on the characterization of viscoelasticity through measurement of the storage (elastic) and loss (viscous) modulus using -carrageen and hyaluronan solutions of different molecular weights and different concentrations depending on temperature (20–50 °C, alternatively, in carrageen, 20–80 °C). The temperature dependence was further measured using an uncommon technique called high resolution ultrasonic spectroscopy (HR-US) which measured relative velocity of selected concentrations of -carrageen and hyaluronan of high molecular weight depending on the temperature of heating and cooling (20–80 °C). The measurements of temperature dependence were carried out for varied oscillation frequencies of rheometer sensor/frequency of ultrasonic waves. Knowledge of temperature dependence of the investigated substances may be applied in drug chemistry, primarily with respect to degradation due to high temperatures. The measured data gives information about sol-gel temperature and gel-sol temperature of carrageen.
Characterization of medical biopolymers by ultrasound spectroscopy
Jugl, Adam ; Krouská, Jitka (referee) ; Hurčíková, Andrea (advisor)
Using high resolution ultrasonic spectroscopy has been investigated hyaluron solutions of various molecules weights depending on their concentration and solution temperature. Furhermore, the influence of ionic strenght on the properties of solutions by dissolving hyaluronan in 0.15 M aqueous solution of sodium chloride. For comparison the properties of the hyaluronan solutions were compared with aqueous solutions of carrageenan. It was found that hyaluronan in solution behaves the same, regardless of the weight, temperature and concentration.
Effect of crowding agents on DNA-surfactant interaction
Sovová, Šárka ; Hurčíková, Andrea (referee) ; Pekař, Miloslav (advisor)
Tato diplomová práce se zabývá vlivem zaplňovacích činidel na interakce v systému DNA-tenzid. DNA o velikosti 4017 párů bází byla připravena polymerázovou řetězovou reakcí, jako templát byl použit plasmid pSB-E1g. Polyetylen glykol (PEG) byl použit jako zaplňovací činidlo a jeho vliv na DNA-tenzid interakce byl zkoumán experimenty založenými na fluorescenci a gelové elektroforéze. Také byl studován vliv iontové síly za použití NaBr na interakce DNA-tenzid za použití zaplňovacího činidla. Data byla vyhodnocena a evaluována v této práci. V úvahu byl brán i možný vliv polyetylen glykolu na kritickou micelarní koncentraci (CMC) tenzidu, bylo provedeno měření CMC pomocí ultrazvuku s vysokým rozlišením, avšak nebyl zjištěn žádný značný vliv zaplňovacího činidla na CMC tenzidu. Část této práce bude zahrnuta v publikaci s anglickým názvem Combined role of macromolecular crowding and cationic surfactant in efficient DNA condensation.
Study of interactions of hyaluronan-amino acids
Jugl, Adam ; Smilek, Jiří (referee) ; Hurčíková, Andrea (advisor)
The master´s thesis deals with the study of the interaction between the polysaccharide hyaluronan of diffrerent molecular weights with the amino acids arginine, lysine, arginine hydrochloride and 6-aminocaproic acid. They are expected interaction between carboxyl groups of hyaluronan and amino groups of amino acids. These interactions were investigated by using ultrasonic spectroscopy, DLS, measuring pH and conductivity. Obtained results were compared with sodium polystyrene sulfonate. With ultrasonic spectroscopy was observed a change of concentration inkrement for titration of amino acid to water or polymers solutions especially for high molecular weight hyaluronan and for NaPSS in combination with 6AKK in concentration range of added amino acid 0–30 mM. The size of this change could mean a degree of interaction between polymers and amino acids. This theory has not been confirmed by other methods. By pH and conductivity measurements interations between arginine and low molecular weight hyaluronan and NaPSS were only confirmed. There was no possibility to make unequivocal conclusions from determination of particle size and zeta potential by DLS. Overall, the issue of the interaction of amino acids with polyanions was proved above expectations complex and will be appropriate to further expand the observations made in this thesis.
Characterization of pectin by ultrasonic spectroscopy
Trtek, Jan ; Kalina, Michal (referee) ; Hurčíková, Andrea (advisor)
Pectin solutions of various concentration in water has been investigated using high resolution ultrasonic spectroscopy. Furhermore, the influence of solvent on the properties of solutions by dissolving pectin in 0.15 M aqueous solution of sodium chloride and buffer PBS at pH 7.4. For comparison the properties of the pectin solutions were compared with solutions of pectate. It was found that pectine changes characteristics in differenet solutions. These changes have been observed due to changes in the parameters of ultrasonic waves.
Interaction of hyaluronan with surfactant CAE
Trtek, Jan ; Pekař, Miloslav (referee) ; Hurčíková, Andrea (advisor)
The diploma thesis is focused on the study of interactions between hyaluronan of various molecular weights with CAE surfactant. This surfactant does not have the exact composition and there is not known their molecular weight. One of the main parameters needed to describe the interactions between surfactant and hyaluronan, there is the determination of critical micellar concentration. The value of critical micellar concentration of CAE is not known yet. All measurements were made for solutions in aqueous solution and 0.15 M NaCl. The determination of the molecular weight of this surfactant was performed by the technique SEC-MALS-dRI. High resolution ultrasonic spectroscopy was chosen to determine the critical micellar concentration and tensiometry was chosen as a complementary method. The interactions of CAE surfactant with polysaccharide of hyaluronan were showed by high resolution ultrasonic spectroscopy and densitometry. Compressibility was calculated from ultrasonic velocity and density.
Characterization of regenerated humic acids
Ivancová, Anna ; Ing. Daniela Šmejkalová,Ph.D. (referee) ; Kučerík, Jiří (advisor)
The work deals with the physical characterization of humic substances, namely potassium and ammonium salts of regenerated humic acids extracted from South-Moravian lignite. The regeneration of lignite was based on the oxidation of lignite by means of nitric acid and hydrogen peroxide. Obtained samples of humic acids were analyzed by elemental analysis, which confirmed that the regeneration changed the distribution of elements in respective humic acids. Diluted aqueous solutions of humates were further analyzed by densitometer and high resolution ultrasonic spectroscopy. Obtained data were used for the determination of the compressibility and hydration. The relationship between those two parameters and way of humic acids preparation was discussed.

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