|
|
Influence of pH on polyectrolyte-surfactant system
Mourycová, Jana ; Omelka, Ladislav (referee) ; Pekař, Miloslav (advisor)
In this bachelor thesis, was studied influence of pH on aggregation polyelectrolyte-surfactant system using fluorescence spectroscopy and pyrene as fluorescent probe was used. As polyelectrolyte, hyaluronan with different molecular weight was used. Two surfactants cationic surfactant cetyltrimethylamonium bromide (CTAB) and nonionic surfactants polyoxyethylene (20) (TWEEN 20) were selected for interaction with hyaluronan. In the pH range from 3 to 10, no signifact changes in the aggregate non-polar core was observed. This mean system is stable against changes in the observed pH range. At system with higher concentrations of cationic surfactant (CTAB) and higher molecular weight hyaluronan occurred phase separation and gel exclusion was observed.
|
|
|
Hyaluronan ionocomplexes for cosmetic and farmaceutical applications
Cimalová, Jana ; Obruča, Stanislav (referee) ; Pekař, Miloslav (advisor)
This bachelor thesis is focused on the study of a system of cationic surfactant – hyaluronan. Using fluorescent spectroscopy the critical micellar concentration of Carbethopendecinium bromide (Septonex) was determined in three environments – water, 0,15 M NaCl, and buffer PBS, with three fluorescent probes – pyrene, perylene, and nile red. It was found that the physiological environments (buffer and NaCl) reduce the value of CMC about one order. During the experiments with native hyaluronan, precipitate and gel formation were observed. The following part dealt with aggregate behaviour of the new biologically acceptable amphoteric surfactant tetradecylfosfocholine (TPC) in the environment of water and NaCl according to the increasing molar molecular weight of hyaluronan. As a fluorescent probe perylene was used. These measurements showed that the molar molecular weight or a change of ionic force has no effect on the value of CMC and therefore there are no interactions with hyaluronan. The last surfactant to study was 1,2-dihexadecanoyl-3-dimetylammonium-propan (DPTAP), which is water insoluble. DPTAP is soluble in chloroform, but after evaporation of chloroform and after addition of hyaluronan, it precipitated. The results so far, have confirmed that in terms of research of aggregation by fluorescence spectroscopy the new cationic surfactants TPC and DPTAP are not suitable for complexation with hyaluronan.
|
|
|
Dynamic surface tension in study of hyaluronan-surfactant interactions
Herzog, Milan ; Žídek, Jan (referee) ; Pekař, Miloslav (advisor)
The main task was to characterize interactions between negatively charged biopolymer sodium hyaluronate and two cationic surfactants: cetyltrimethylammonium bromide (CTAB) and tetradecyltrimethylammonium bromide (TTAB). Interactions between sodium hyaluronate and these surfactants are based on their different charge and can be detected by changes of surface tension. The influence of constant addition of sodium hyaluronate (MW = 90 and 1400 kDa) on interface tension values at increasing bubble lifetime was observed. For this purpose, the maximum bubble pressure method was choosen. The measurements were performed in water and in 0,15 mol•l-1 NaCl solution. The obtained results can be used as for description of dynamic properties of hyaluronate-surfactant systems as, e.g., in targeting drug delivery.
|
|
|
Development of non-energy use of lignite
Macháčková, Mirka ; Sedláček, Petr (referee) ; Pekař, Miloslav (advisor)
This bachelor thesis deals with the study of non-energetic use of lignite. The use as a sorbent is one of many possibilities. Sorption of chloride and sodium ions was carried out on natural lignite from the South Moravian, lignite washed with deionized water and lignite enriched with calcium ions. The experiments were realized monitoring pH, electrical conductivity, amounts of sodium and chloride ions in the prepared samples. Chemical oxygen demand was determined in the extract of lignite. This measurement was carried out in accordance with norm ČSN 83 0540-8 Chemical and physical analysis of waste water: Determination of dichromate oxidability. For use in agriculture were investigating the possibility of preparation of humic hydrocolloids by high speed dispergator and planetary mill. The ideal ratio of lignite and water was determined. The liquid and solid humic hydrocolloids were prepared by mechanochemical activation the lignite. These were characterized - particle size, UV-VIS spectroscopy of prepared extracts and sedimentation.
|
|
|
Preparation and characterization of novel application forms of humic substances in combination with water sorbents
Nováčková, Táňa ; Pekař, Miloslav (referee) ; Sedláček, Petr (advisor)
This bachelor’s thesis discusses an applicability of hydrogel forms-based composite materials of humic acids and commercial water sorbent. According to the literature review, methods of incorporation of humic acids into commercial sorbents of water under various conditions and the resulting materials were subsequently characterized. In the characterization, major attention was paid to the determination of the water content and the swelling characteristics. Preparation of the composite materials was directed to use their sorption abilities and ability to control the release of humic substances in agriculture.
|
|
|
Preparation and characterization of novel materials based on combination of humic acids and chitosan
Kozelková, Aneta ; Pekař, Miloslav (referee) ; Sedláček, Petr (advisor)
This bachelor thesis deals with an application potential of newly developed forms of mixed composites of humic acids, chitosan and commercial granulated inorganic fertilizer.. The main aim was to test some preparation methods selected on the basis of literature search. The experimental part focused on characterization of prepared composite materials, the main attention was paid to the sorption of water, release of humic acid and mineral nutrients into solution, and last but not least, on the mechanical properties of resulting materials. The motivation of this work comes from the potential of agricultural and environmental applications of such composites resulting in a renewal of previously exhausted organic content of soils and consequent interruption of substantial soil degradation.
|
|
|
Support of physical interaction between hyaluronan and selected hydrophobic solutes
Michalicová, Petra ; Kislinger, Jiří (referee) ; Pekař, Miloslav (advisor)
The method of fluorescence spectroscopy was applied for the studying of the way of the hyaluronan-fluorescence probe system`s preparation on mutual interaction in water. Several experiments with fluorescence probes pyrene, prodan, perylene and diphenylhexatriene (DPH) had been submitted. The first part of the experiments deals with the verification of the results of T. Brown`s work and it was focused on the study of simple interaction between hyaluronan and hydrophobic compounds. In the second part of the work hyaluronan was dried at higher temperature followed by adding of the fluorescence probe. The aim of this method was the distraction of hyaluronan`s moisture packaging and the opening up the hydrophobic parts of the chain for the fluorophore. Although wide concentration ranges of fluorescence probes had been tested in the first experiments, the interactions hadn`t been observed. The similar results were obtained in the second part of the experiments.
|
|
|
Coal humic acids and their applications
Hedvigy, Marek ; Taraba,, Boleslav (referee) ; Pekař, Miloslav (advisor)
The dark-colored humic acids are important parts of less coalified coals. Thanks to their properties, they are used in agriculture, veterinary medicine, industry and in modifications of the soil in the environment. In my work, I included the survey of producers of the coal humic acids and their application. An extraction of these humic acids and a determination of their content in the original raw material has been made on a domestic sample.
|
|
|
Humic acids in medicine and cosmetics
Šmídová, Helena ; Sýkorová,, Ivana (referee) ; Pekař, Miloslav (advisor)
The main concern of this study was to form a web and literature search focused on the known theoretical knowledge, patent application and the actual realization, for the use of humic acids or material containing humic acids in human and veterinary medicine and cosmetics. The output is also a proposal to be promising directions in exploring these areas. The introduction deals with humic substances in general with emphasis on humic acids, history of humic chemistry and structure of humic substances. The second part deals with medical aspects, pharmacological effects and the use of humic substances in human medicine, veterinary medicine and cosmetics, also takes account of humic substances from the perspective of the environment. The task of third experimental part was to learn the basics of isolation and characterization of humic acids (measurement of IR and UV / VIS spectra and determination of moisture and ash in samples of humic acids).
|
|
|
Cationic fluorescence probes in a polyanion-surfactant system.
Mondek, Jakub ; Šmejkalová, Daniela (referee) ; Pekař, Miloslav (advisor)
In this bachelor thesis were studied properties of aqueous solutions of hyaluronan and celytrimethylamonnium bromid with help of acridine orange as fluorescence probe. At first, this thesis was focused on interactions of acridine orange and hyaluronan. Emision and excitation spectra of acridine orange were observed. Result of these measurement was bonding of acridine orange dimer to carboxylic group of hyaluronan. Next studied interaction was interaction of cetyltrimethyl amonium bromid with acridine orange – hyaluronan system. Result of these interaction was, that molecules of cationactive surfactant pushed away dimers of acridine orange and took place of dimer of acridine orange on carboxylic group of hyaluronan. Dimer of acridine orange was changed into monomers. The reason why this thesis was focused on study of aqueus solutions of hyaluronan with cationactive surfactant is benefit of hyaluronan – surfactant system in research of transport system for target distribution of drugs.
|
guest ::
