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Preparation and application particles from copolymer of P(3HB-co-4HB)
Ostanina, Kseniia ; Sedláček, Petr (referee) ; Obruča, Stanislav (advisor)
This bachelor thesis deals with preparation of particles from poly(3-hydroxybutyráte-co-4-hydroxybutyráte). Copolymer was dissolved in acetone and then the solution had been dosed into the anti-solvents. Acetone and anti-solvent are perfectly miscible. Theoretical part focuses on the properties of the copolymer, its production and potential use in medical applications. In the experimental part the copolymer was dripped into selected anti-solvents by syringe and pipette above and below the surface of anti-solvent. The following anti-solvent were chosen: water, methanol, dimethylsulfoxid (DMSO), 50 % acetone-water, 75% acetone-water, 50 % methanol-water, 75 % methanol-water mixtures. There were three copolymers used with different compositions of 4HB units (63 %, 87 % a 33 %). Copolymer composition was analyzed by gas chromatography. Copolymers were prepared by bacterial strain Aneurinibacillus sp. H1. Due to the results particles of size approximately 100-500 nm can be prepared by methods described in this work. The produced particles can be successfully used in medical applications.
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Interaction of drugs with soil organic matter - calorimetric study
Papko, Nadezhda ; Sedláček, Petr (referee) ; Klučáková, Martina (advisor)
This bachelor thesis is focused on the study of the interaction of soil organic matter with selected drugs using isothermal titration calorimetry. Two fulvic acids and drugs were used in the experiment: ibuprofen, pyridine sulfate and diclofenac. The scope of the work was to test the method for studying the interactions between fulvic acids and drugs and to optimize it for specific humic substances and drugs. Isothermal titration calorimetry includes the possibility to determine very important thermodynamic parameters, which were determined during the measurement of the bachelor's thesis. The main goal was to measure and assess whether the interactions take place and what the thermal effects are.
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Development and optimization of ointment preparation for burn healing
Müllerová, Kristýna ; Sedláček, Petr (referee) ; Enev, Vojtěch (advisor)
This bachelor's thesis aims to prepare ointments based on an ointment base with the addition of a bioactive component of chlorophyll according to a recipe from an unknow doctor. The basic characteristic of emulsions was performer in the theoretical part, their instability and possible methods of stabilization were described. Furthermore, the reader is acquainted with the bioactive substance of chlorophyll, selected ointments for the healing of burns and wounds and finally with the use in medicine. In the Experimental part, the preparation of emulsion bases of ointment was described. Based on a performed analysis of stability using analytical centrifuge, two ointments bases were selected, to which other components were added – chlorophyll, beeswax, and chamomile extract. The stability of completely prepared ointments was studied at 25 °C and 37 °C, this analysis was performed even after a longer time interval. Using ATR-FTIR spectrometry the present functional groups were identified at prepared ointments, individual components of the ointments base and chlorophyll. Based on the stability measurement of the prepared ointments and rheological measurements (oscillation and rotational measurements), it was evaluated that the best properties were shown by the prepared ointment with an ointment base consisting of 30 wt. % white vaseline and 70 wt. % synderman.
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Hydrogel carriers of microorganisms for modern environmental aplications.
Súkeník, Martin ; Slaninová, Eva (referee) ; Sedláček, Petr (advisor)
This bachelor thesis deals with the optimization of cultivation and gelation procedures by bacterium Azotobacter vinelandii, which belongs to a PGPR group, capable of synthesis of intracellular polyhydroxyalkanoates and extracellular alginate. The alginate produced by the bacteria is crosslinked with a calcium chloride solution to form a hydrogel carrier containing the described bacterium. This unconventional concept simplifies bacterial encapsulation and production of hydrogel carriers, furthermore expands its usability in modern environmental applications. In the first part of this thesis, three strains (DSM 85, 87, 720) were selected to measure a concentration of produced alginate, its molecular weight was determined by a SEC-MALS technique and M/G ratio was analysed by infrared spectroscopy. The Azotobacter vinelandii strain DSM 87 reached the highest concentration of the alginate (4.9 ± 0.6) g/l by gravimetric determination on the 5th day of cultivation. The concentration of produced PHB ranges from 48 to 6 % of CDW, which was determined by gas chromatography. Nevertheless, the strain DSM 720 showed the best gelation properties and was used in the second part of this thesis for further optimization of the cultivation process, and for the analysis the formation of gelation procedure under different temperatures, gelation time and concentrations of crosslinking solution. The formed gels were compared by rheological measurements of amplitude and frequency tests.
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Utilization of vibrational spectroscopy for in-situ qualitative and quantitative analysis of polyhydroxyalkanoates in microbial biomass
Kevélyová, Barbora ; Enev, Vojtěch (referee) ; Sedláček, Petr (advisor)
The aim of this bachelor thesis was to evaluate the applicability of selected methods of vibrational spectroscopy for qualitative and quantitative analysis of biomass, which contains polyhydroxyalkanoates. Fourier-transform infrared spectroscopy, that uses attenuated total reflection technique (ATR-FTIR), was chosen for this experiment. Poly(3-hydroxybutyrate-co-4-hydroxybutyrate) has been studied in Cupriavidus malaysiensis, Thermomonas hydrothermalis and Aneurinibacillus thermoaerophilus sp. H1. Data were obtained by evaluating the infrared spectra, which were then compared with the results of performed gas chromatography. Visual changes in the spectra were also observed along with crystallinity. No correlation was detected between the data obtained by gas chromatography and by the method ATR-FTIR in quantitative analysis. Thus, this method is not suitable for determining the content of poly(3-hydroxybutyrate-co-4-hydroxybutyrate) in biomass in the set experiment and the bacteria used. On the other hand, the method was successfully used for in-situ qualitative analysis of copolymer in the samples of Aneurinibacillus thermoaerophilus sp. H1. The degree of data correlation was relatively high in the given experiment. With these findings, ATR-FTIR is a suitable analytical method for determining the monomer composition of poly(3-hydroxybutyrate-co-4-hydroxybutyrate) in this strain. Comparison with the PHA producer Cupriavidus malaysiensis showed that this method is not universal for all types of microorganisms observed in this thesis.
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Utilization of vibrational spectroscopy in study on interactions between humic substances and organic ions.
Stehlíková, Kristína ; Enev, Vojtěch (referee) ; Sedláček, Petr (advisor)
The main objective of this bachelor thesis was to validate the potential of the utilization of vibrational spectroscopy in the study on interactions between humic substances and organic ions. Unmodified (HA) and methylated humic acids (mHA) were chosen as model humic substances and organic ions were represented by methylene blue, rhodamine 6G and Septonex. Firstly, a suitable infrared spectroscopy technique was chosen. The results of optimization measurements showed that spectra with the best resolution can be obtained using the DRIFTS technique. The next part of the thesis discusses the effect of methylation in the structure of humic acids. Significant differences were recorded in mHA compared to the unmodified humic acids. Finally, the spectra of humic acid – organic ion complexes were compared to the spectra of prepared blank samples. It was noted that the spectra of complexes are not only a simple sum of the pure individual substances’ spectra, but also shifts and changes in the intensity of different absorption bands were recorded there. It suggests that non-covalent interactions played an important role in the complexes. Infrared spectroscopy was proved to be a useful method for investigating these interactions.
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Humic substances as active or auxiliary pharmaceutical component
Blahuš, Petr ; Kalina, Michal (referee) ; Sedláček, Petr (advisor)
This thesis examines the effect of the potassium lignohumate on the transfer speeds of analgesic drugs through the synthetic Strat-M® membrane. In order to examine the transfer of these substances, vertical diffusion cells were used and the final samples were analysed using UV-VIS spectrometer and HLPC. The intention of this thesis was to optimise the process of preparing diffusion cells, to compare the transfer speeds of pure active substances and active substances with the potassium lignohumate, and to compare the permeability of Strat-M® membranes, by using pig skin membranes which were used in the previous study that this thesis continues from. The primary discovery was that the lignohumate slowed down the transfer of active substances through the membrane.
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The influence of biochar on physico-chemical properties of soil
Polášková, Nikola ; Sedláček, Petr (referee) ; Smilek, Jiří (advisor)
This thesis is focused on assessment of the influence of biochar on the soil physico-chemical properties (particle density, dry density, porosity, water retention capacity and maximum water holding capacity, oxidizable carbon content, total nitrogen content, phosphorus, potassium and magnesium content). The selected and examined soil types were: cambisol, fluvisol, chernozem and regosol. There were two types of biochar used for analysis – NovoTerra and Sonnenerde. Soil samples were dried to constant weight and adjusted to grain-size fraction under 2 mm, respectively 0,25 mm. The oxidizable carbon content was measured by oxidation using a mixture of potassium dichromate and sulphuric acid (Walkley-Black method), the total nitrogen content was measured by kjeldahlization and P, K and Mg content was measured using Mehlich 3 extraction and ICP-OES spectrometer. The results show that biochar has a significant influence on soil characteristics depending on the type of biochar and soil we use for biochar application. This thesis can be used to clarify the complex issues in terms of soil in Czech Republic or it can be used by farmers considering using biochar as a soil additive with the intention to increase productivity and fertility of soil.
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Limitations of Incompressible Encodings
Sedláček, Petr ; Hubáček, Pavel (advisor) ; Mareš, Martin (referee)
This thesis studies the limitations of incompressible encodings with information- theoretic security. We demonstrate a flaw in the existing proof of the impossibility of constructing incompressible encodings information-theoretically. Our main contribu- tion is a full proof of impossibility of existence of non-trivial information-theoretically secure incompressible encoding schemes. In the first part of the thesis, we introduce the basics of incompressible encodings and provide the necessary definitions. Next, we present the flaws in the existing argument and provide explicit counterexamples to them. Throughout the rest of the thesis, we gradually construct a complete proof. We start by showing the impossibility under a few additional restrictions on the correctness and structure of the schemes that we subsequently remove one by one. Finally, we present an adversary able to break any non-trivial incompressible encoding scheme. 1
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