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Rheology of collagen hydrogels and its nanocomposites
Voldánová, Michaela ; Vojtová, Lucy (referee) ; Jančář, Josef (advisor)
This bachelor thesis deals with the phenomenological description of the rheological behavior of pure collagen I and its nanocomposites with addition of hydroxyapatite in four concentrations. Measurements were performed on a rheometer in the configuration cone – plate for a range of shear rates from 0 s-1 to 100 s-1 under defined conditions. At 4 °C, the collagen in samples of a specific composition remains dissolved; collagen retains his native character and the precursors of hydrogel are in the liquid state. By heating the aqueous solution of collagen with neutral pH leeds to spontaneous crosslinking process into fibrillar structure. At 37 °C, fibrils grow into the gel structure, however, the rate of its formation is dependent on the amount of collagen fibers. The measured data are processed in the form of flow and viscosity curves, from which the rheological behavior of the sample or structural and transformational changes in response to mechanical stress and temperature changes are evaluated and compared. This knowledge can be used to manipulate with hydrogels. Generally, it can help as a basis for further development of collagen, its interaction with HAP and factors influencing their stability or effectiveness.
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Methodology for experimental study on the release of humic acids from hydrogel application forms.
Palanová, Veronika ; Klučáková, Martina (referee) ; Sedláček, Petr (advisor)
Hlavnou náplňou bakalárskej práce bolo navrhnúť a optimalizovať metódu experimentálneho štúdia uvoľňovania huminovej látky z gelových matríc, ktoré boli vytvorené pomocou bežných kozmetických a farmaceutických zahusťujúcich látok. Pre štúdium uvoľňovania tejto aktívnej látky bola zvolená difúzna aparatúra vo vertikálnom usporiadaní, tzv. Francova cela. Výluhy gelových vzoriek boli podrobené spektrofotometrickým meraniam. Vzniklé interakcie medzi roztokmi lignohumátu a rôznych typov zahusťujúcich látok boli experimentálne stanovené. Celý proces optimalizácie metódy pre uvoľňovanie huminovej látky z gelových foriem bol diskutovaný.
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Hyaluronan hydrogels for medical applications
Janča, David ; Krouská, Jitka (referee) ; Venerová, Tereza (advisor)
This work studies properties of hydrogels prepared by the interaction of polyelectrolyte hyaluronate with cationic surfactant cetyltrimethylammonium bromide (CTAB) in a model physiological solution of 0,15 M NaCl. Effects of different pH and final pH of different samples of hydrogels were studied. Furthermore, stability of hydrogels was observed by fluorescence spectroscopy, where pyrene was used as a fluorescence probe, and isothermal microcalorimetry. It was found that low temperature disrupts gel integrity and it is not recommended to expose hydrogels to other than a neutral pH.
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Influence of polyelectrolyte biopolymers on transport of ions
Kolesa, Pavel ; Kalina, Michal (referee) ; Klučáková, Martina (advisor)
This bachelor thesis was focused on the study of interaction of cationic biopolymer with model diffusion probe (basic organic dye) in the gel media by diffusion processes. The main aim was optimization of simply laboratory diffusion technique (unsteady diffusion in a cuvette) because of study on interactions of chosen biopolymer with model compound depending on temperature. Cationic chitosan was chosen as model biopolymer. The model diffusion compound was chosen organic anionic dye Acidal Black 10B (C.I. 20470). Diffusion processes in plastic cuvettes were realized by transport of dye in a hydrogel media based on thermoreversible polysaccharide – agarose. The important content of this method is a monitoring of the time progression of diffusion profile by UV-VIS spectrophotometry. Important part of this work was characterization of hydrogel medium and biopolymers by basic physical-chemical methods. This bachelor thesis is focused on reactivity of chitosan and its behavior in different systems. Unsteady diffusion in cuvettes appears to be a universal method for the study on reactivity of biopolymers.
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Study on Reactivity of Cationic Biopolymer by Simple Diffusion Techniques
Tesařová, Barbora ; Kalina, Michal (referee) ; Smilek, Jiří (advisor)
This bachelor thesis is focused on study of chitosan reactivity by simple diffusion processes realized in hydrogel media based on agarose. Mechanical properties studied by oscilatory measurements and the pore size were determined at agarose gels with the addition of chitosan as the main parameters influenced the transport properties. The main goal of this work is the investigation the reactivity of chitosan. Agarose is used only as a supporting matrix for the formation of a hydrogel. The state of the art is aimed primarily on the study of chitosan reactivity based on already published scientific papers.
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Behaviour of hydrophilic fluorescent probe Oregon Green 488 in hydrogel environment
Lacko, Kata ; Venerová, Tereza (referee) ; Mravec, Filip (advisor)
The aim of this bachelor’s thesis is to study the behavior of a hydrophilic fluorescent probe named Oregon Green 488 in hydrogel environment. The hydrogel was created using sodium hyaluronan and CTAB (cetyl trimethylammonium bromide) as a cationic surfactant. Solution of 0.15 M NaCl was used as a solvent, which provides physiologic conditions in the sample. The behavior of the fluorescent probe was characterized by steady-state and time-resolved fluorescent measurements. To obtain the emission spectra of the probe and to find the emission maximum the method named TRES (time-resolved emission spectra) was used. Fluorescence intensity decay measurements as a function of wavelengths allowed to create deconvolution of the emission spectra, which provided information about the fluorescent lifetime and the probe’s states’ relative representation in the solution. Hydrogels were examined 5 days and 1 month after the preparation and the results were compared. Oregon Green 488 demonstrated one fluorescent lifetime in the hydrogel environment in the range, 4,14,45 nm in the fresh hydrogel and 4,14,6 nm in the stable hydrogel. The emission maximum was obtained at 525 nm in both cases. The fluorescent probe’s behavior in the hydrogel environment is stable, presumably there are no interactions occurring between the hydrogel and the probe. Furthermore, no interactions were recorded between the probe and hyaluronan.
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Preparation and application of physical hyaluronan gel
Kovářová, Lenka ; Krouská, Jitka (referee) ; Venerová, Tereza (advisor)
Bachelor's work is concerning by research in physical hyaluronan gel area. Research is focusing on its preparation, especially by interaction of hyaluronan (HyA) solution with opposite charged surfactant in physiological solution (0,15 M NaCl). In the first part of work I found out influence of molecular weight, concentration of original hyaluronan solution and the ratio of binding sites on hyaluronan chain and surfactant on amount of solids in gel, expressed in percent. Finally we can say, that this value is not influenced by molecular weight of HyA neither relation of binding sides. On the other side, concentration of original HyA solution has significant influence on amount of solids in gel. There was also researched process of gel swelling, where was set amount of water (in percent) able to take dried gel back. Analogical conclusion has been reached like amount of solids in gel. In other part were researched influence of hyaluronan molecular weight and the ratio of binding sites on hyaluronan chain and surfactant on formation of excimers and spectrum change by fluorescence spectroscopy. Pyrene, 1,3-bis(pyren-1-yl)propane (P3P) and prodan were used as fluorescence probes. Excimer emission showed at P3P, while there was no growth of intensity at 470 nm for pyrene. It was found that molecular weight does not affect the value of the ratio of excimer and monomer probe P3P, or the ratio of the first and third peaks of pyrene. The ratio of binding sites HyA and surfactant influence only relation of excimer to monomer (P3P probe), while influence to relation 1:3 hasn't been noticed for pyrene. I have compared spectrum of developed gel for prodan probe, relevant solid and swelled gel by return. It also served for drying and swelling process visualisation.
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Vliv struktury pěstebních školkařských substrátů na kvalitu produkce
Flaschková, Karolína
The experimental plots Department of Breeding and Propagation of Ornamental Plants Gardening faculties in Lednice, was founded in 2013-year vegetation attempt. Experi-mentally evaluated the influence of substrates on the root system of ornamental plants. The experimental wood-fault was used Berberis thunbergii 'Golden Ring'. Experimental medium was creature-no RKS II substrate and the substrate for broadleaf blended with soil conditioner. The plants were evaluated morphological parameters such as plant height, number of shoots, the average length of shoots, root collar diameter and the volume of the root system.
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Použití alternativních surovin pro pěstování okrasných dřevin v kontejnerech
Frlausová, Monika
Was experimentally evaluated the effect of selected nursery growing media development and quality of the crops produced. Added alternative components were observed coir, peat and coconut hydrogel. As a model plant was chosen for the experiment Cotoneaster buxifolius ,Nana', an attempt was one year. Parameters were evaluated: plant height, average length of shoots, number of shoots, root collar diameter, the volume of the root system. The raw material, which should in the future to replace peat in growing nursery substrates showed a positive effect on the quality and quantity of the crops.
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Optical Absorption Sensors for Evaluation of Yeast Acidification Power
Rychtáriková, Renata ; Frančič, N. ; Hetflejš, Jiří ; Kuncová, Gabriela ; Gabriel, P. ; Lobnik, A.
The acidification power test provides a fast and simple method of assessing the ability of cells to perform a successful fermentation. It has been used as a rejection criterion for assessing the technological quality of starter yeast cultures in brewing, cider production, baking, as well as cheese making based on lactic acid bacteria. The cell acidification power responses to pH decrease of the environment after glucose addition. We have prepared novel recognition elements of pH sensors suitable for evaluation of yeast acidification power by absorption of two pH sensitive sulfonphthalein dyes (bromocresol green and bromophenol blue) into hydrogel of poly(2-hydroxyethyl methacrylate-co-ethylene dimethacrylate). The absorption spectra, function ranges, pKa values, and response times for each absorbed dye were evaluated, compared with the free dyes, and further discussed with regard to its application to the acidification power test.
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