|
|
Preparation and characterization of hydrogel delivery systems from poly-gamma-glutamic acid
Mai, Thuy Ha ; Smilek, Jiří (referee) ; Sedláček, Petr (advisor)
The presented diploma thesis focuses on the development and preparation of model poly--glutamic acid based hydrogel carrier systems. For the hydrogel carrier preparation, methods based on physical interactions between polyelectrolyte and oppositely charged multivalent ion or oppositely charged macromolecule were proposed. Based on the pilot experiments, trivalent iron cation and chitosan were selected as suitable crosslinking agents. By crosslinking -PGA via ferric cations a successful bead formation has been accomplished and attempts have been made for a preparation of beads smaller than 1 000 m by employing microencapsulation techniques. Rapid disintegration of -PGA beads occurred upon immersion of the beads in water making these systems unsuitable for drug carrier applications. Interactions between -PGA and chitosan lead to polyelectrolyte complexes formation and by optimizing concentrations and pH of polyelectrolyte solutions, a formation of homogenous looking hydrogel with high water content (>0,9) has been achieved.
|
|
|
Functional technical materials modified by lignin isolated from winery by-products
Chovanec, Martin ; Sedláček, Petr (referee) ; Kovalčík, Adriána (advisor)
In this thesis, the possibility of producing composites of epoxy resin and lignin isolated from grape skins was examined. The motivation was to reduce the amount of bisphenol A, which is nowadays used to produce most of the epoxy resins and is the main environmental pollutant. The composites were prepared by mixing commercial bisphenol A diglycidylether (DGEBA) with lignin samples. In this work, the sodium hydroxide pulping method in a hydrothermal autoclave was used to isolate lignin. The content of reducing sugars, lignin, and fatty acids in the sample of grape skins was determined and the chemical composition was determined by Fourier transform infrared spectroscopy (FT-IR). The chemical and thermal properties of isolated soda lignin were compared with commercial Kraft lignin and analyzed by elemental analysis, FT-IR, thermogravimetric analysis, and ash content determination. Epoxidized lignin was prepared by three methods, which were compared based on yield, epoxide equivalent, and chemical composition. Samples of unmodified soda lignin and epoxidized soda and Kraft lignins were selected for the preparation of epoxy composites. Experiments have shown that isolated soda lignin was not suitable for the addition to epoxy resins, unlike Kraft lignin. Thermal and viscoelastic properties of the prepared composites with a homogeneous structure were analyzed. It was found that the epoxy composites with added epoxidized Kraft lignin showed lower material stiffness and the glass transition temperature was significantly shifted to lower temperatures.
|
|
|
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.
|
|
|
Program-controlled freeze drying for the preparation of the delivery system of native hyaluronan and hydrophobic molecules
Waczulíková, Kristína ; Sedláček, Petr (referee) ; Enev, Vojtěch (advisor)
The amphiphilic nature of the hyaluronan biopolymer facilitates interactions between its hydrophobic portions of the chain and the hydrophobic ligands, making it one of the promising compounds that can be used as a suitable carrier for drug delivery. Therefore, the aim of this diploma work was by means of a program-controlled freeze-drying to prepare a system based on native hyaluronan, which would be capable of transporting hydrophobic drugs. Perylene, pyrene, prodan and 1,6-diphenyl-1,3,5-hexatriene fluorescence probes were used as model compounds to simulate hydrophobic drug-hyaluronan interactions. Freeze-drying efficiency was studied using infrared spectrometry and scanning electron microscopy. ATR-FTIR spectrometry confirmed for all probes but pyrene the hydrophobic interactions between the hyaluronan and probe molecules based on the presence of the C=C bond valence vibration absorption band in the aromatic probe rings. From the IR spectra, it was not possible to confirm with certainty the presence of residual tert-butyl alcohol in the samples. SEM photographs revealed that increasing the pressure during drying process had a positive effect on the quality of the lyophilized sample in the second series of samples. Interactions of individual fluorescent probes with hyaluronan were studied using steady-state and time-resolved fluorescence spectrometry. Positive results have been obtained, indicating the presence of fluorescent probes interacting with the hydrophobic regions of the hyaluronan chains. The results of this work can contribute to the development of carrier systems in the field of targeted drug distribution.
|
|
| |
|
|
The preparation and evaluation of microparticles containing colloidal silver
Sedláček, Petr ; Dittrich, Milan (advisor) ; Kvítek, Libor (referee)
In the Doctoral thesis is presented theoretical overview of relevant scientific knowledge concerning preparation and use of silver colloidal particles enlarged with technical information concerning drying and quality control methods of dispersion systems. Experimental section of the work is focused on two methodically different areas. The first one is dedicated to newly developed procedure of increasing colloidal silver particles concentration, the second one to the approach to the system stabilization. Kinetics of nanosuspension concentrating is studied and short-time stability of concentrated systems is subsequently monitored. The influence of model adsorption polymers on parameters and behavior of colloidal system is tried. Also nanosystem spray drying method and products image analysis are solved in the thesis.
|
|
|
Olomouc cheese - production, business, consumption, 1938-1960
Sedláček, Petr ; Kubů, Eduard (advisor) ; Jakubec, Ivan (referee)
The diploma thesis deals with topic of production, enterprise and consumption of "Olomoucké tvarůžky" (Olomouc cottage cheese) in a 1938-1960 period on the ground of bohemian lands, or Czechoslovakia respectively. It summarizes development of this branch up to the year 1938 and observes how it was affected by the consequences of the Munich Treaty. The thesis puts closer look at the types of state interventions in production of Olomouc cottage cheese in war and postwar time. It also observes process of socialization and subsequent nationalization of private businesses in 1950s. Then it focuses on major aspects of business in this branch and brings more detailed study of three typical entrepreneurs according to the scale of their involvement. The thesis furthermore characterizes production of Olomouc cottage cheese as an individual branch of dairy industry. It surveys number, form, regional dislocation and machinery of businesses. Then it considers amount of production of Olomouc cottage cheese, its relation to total cheese production, to type of plant and region. It deals with number, structure and position of employees in Olomouc cottage cheese businesses. It also concerns export of Olomouc cottage cheese. Last chapter inquires position of Olomouc cottage cheese in consumption habits of population...
|
|
|
Nursing care of the child with acute lymphoblastic leukemia after allogenic bone marrow transplantation
Janírková, Eliška ; Heřmanová, Jana (advisor) ; Sedláček, Petr (referee)
Souhrn Tato práce je rozdělena do několika částí. První částí je stručné anatomicko fyziologické shrnutí, co je kostní dřeň, krvetvorba a rozdělení krevních buněk. V druhé, klinické části práce popisuji akutní lymfoblastickou leukemii, její etiopatogenezi, epidemiologii, diagnostiku, léčbu, paliativní léčbu a transplantace kostní dřeně. Třetí část práce obsahuje základní údaje o nemocném a předtransplantační a potransplantační průběh. V ošetřovatelské části uvádím, co je ošetřovatelství a ošetřovatelský plán, stručně popisuji model Gordonové. Ošetřovatelská část dále obsahuje ošetřovatelskou anamnézu, stanovené diagnózy k dlouhodobému plánu péče, edukaci a psychosociální péči. Na závěr práce je stanovena prognóza u dítěte, o které jsem pečovala.
|
|
|
Mucin hydrogels - artificial models of native mucus systems
Mikušová, Janka ; Obruča, Stanislav (referee) ; Sedláček, Petr (advisor)
The scope of this masters thesis is the preparation of a model mucin system and its utilization as an artificial model of the native mucus system. The creation of this model system, according to several designed methods was a part of experimental part of the thesis. The preparation of mucin system comprised of physical and chemical methods of hydrogel formation, screening and characterisation of the various physical conditions of the mucin properties on its molecular level, and the preparation of sorbent with sorption surface containing mucin. Methods of light scattering, namely dynamic light scattering (DLS), used for mucin particles size change monitoring, and electroforetic light scattering (ELS), used for Zeta potential change monitoring, were used for the screening of the impact of physical factors on the properties of mucin.For the characterisation of impact of the temperature on changes in mucin sctructure was, apart from monitoring of light scattering, used also a diferential scanning calorimetry (DSC), which registered temperature value, at which mucin thermal denaturation occurs. In the next part of the thesis we subdued the created sorption surfaces to various physical-chemical analyses, which task is the characterisation and projection of surface and confirmation of mucin presence.Substancial part in monitoring and characterisation of changes in surface sctructure of sorption surface was accomplished by Fourier transform infrared spectroscopy (FTIR). Scanning electron microscophy (SEM) was used for the final, more detailed, projection of the mucin enriched, sorbent surface structure. Suggested methods of mucin hydrogel, didnt prove sufficient results for the possibility of application of hydrogel as a artificial model of real mucus system, but the sorbent application was indicated as a suitable alternative and an instrument for the further mucin behaviour research and possibly subsequent bacterial adhesion, which represents the first step in the formation of the bacterial biofilm.
|
|
|
Utilization of biosurfactants for incorporation of hydrophobic domains into modern controlled-release systems
Nešpor, Tomáš ; Pekař, Miloslav (referee) ; Sedláček, Petr (advisor)
This work deals with the current topic of carrier systems. Since the biggest problem is the passage of hydrophobic drugs through the bloodstream, or through universal body barriers (eg blood-brain), it is necessary to chemically modify these carriers in order to be able to administer hydrophobic substances effectively. Based on a literature search, several systems are designed and subsequently studied, in which there is a presumption of possible use for carrier systems and at the same time they have biosurfactants incorporated in them due to their ability to solubilize hydrophobic molecules. The theoretical part of this work will describe the individual biosurfactants, the process of their production, their physicochemical properties, and the possibility of their use in carrier systems. At the same time, the individual carrier systems, the procedure of their preparation, the possibilities of their use are described, and their advantages and disadvantages are also compared. In the practical part, the screening of both individual substances and their mutual interactions, as well as methods used to study the emerging structures is then performed. The study of molecular interactions is primarily performed using the technique of dynamic light scattering. The next part describes the optimization of hydrogel formation with incorporated biosurfactants in their structure and then the formed gels are subjected to rheological and solubilization tests. The study of the internal structure of these gels is performed using a scanning electron microscope.
|
guest ::
RSS feed.