National Repository of Grey Literature 193 records found  1 - 10nextend  jump to record: Search took 0.01 seconds. 
Security of Trapdoor Permutations under Preimage Leakage
Sedláček, Petr ; Hubáček, Pavel (advisor) ; Göloglu, Faruk (referee)
This thesis explores preimage leakage-resilient trapdoor permutations (PLR-TDPs) and their applications in proofs of storage replication and incompressible encodings. The thesis consists of three chapters covering the trapdoor permutations, formal definition of PLR-TDPs, and analysis of security properties of PLR-TDPs. The first chapter provides an overview of trapdoor permutations (TDPs), their def- initions, and applications in proofs of storage replication. Our results are presented in the second and third chapters. The second chapter formally defines PLR-TDPs and demonstrates their use by constructing a simple incompressible encoding in the random oracle model. The third chapter focuses on the existence of PLR-TDPs. It demonstrates the strong preimage leakage-resilience of fully random TDPs in an idealized model. We are the first to provide a partial formal justification for the conjecture of the preimage leakage-resilience of practical TDPs, such as RSA or Rabin permutations.
Material flow concept of a production line supply
Sedláček, Petr ; Dorušáková, Kamila (referee) ; Zeizinger, Lukáš (advisor)
The content of this thesis is a research analysis of individual concepts in the field of corporate logistics with an emphasis on intra-company transport. In the practical part, the current state of the production line loading is evaluated and new variants of line supply are made on the of the given parameters. The work also includes the creation of simulation models of all variants in the Plant Simulation program and conclusions are drawn based on the data obtained.
Preparation and characterisation of coatings for controlled-release fertilizers
Jašek, Vojtěch ; Sedláček, Petr (referee) ; Figalla, Silvestr (advisor)
The literary research of this Master's thesis is dedicated to controlled-release fertilizers (CRF). There is written the description of particular representatives of this kind of fertilizer and it also contains principles of nutrition's release mechanisms. Theoretical part is mainly focused on coated fertilizers, materials used for their production, coating technological processes and on a mathematical description of the diffusion transport which is the key of the mass transfer through polymer coatings. The laboratory preparation of innovative coatings based on modified vegetable oils is the main part of the experimental part of the thesis. It consists of the precursors' synthesis which can be applied on the fertilizer's surface in a liquid phase and polymerized by the UV-radiation in combination with an appropriate photoinitiator. There is described the synthesis of additional modifiers of precursors' viscosity and coatings' diffusive properties based on bio-source reactants such as sorbitol or ethyl lactate. The synthesized products are characterized by various methods such as volumetry, FTIR method or viscosimetry. The last part of the thesis contains the description of diffusive characteristics of coatings prepared out of the synthesized precursors.
Modeling diffusion in hydrogels
Vrána, Matouš ; Sedláček, Petr (referee) ; Pekař, Miloslav (advisor)
This bachelor thesis is focused on basic knowledge about hydrogels and their potential uses, Brownian motion in hydrogels and it’s connection with diffusion and the possible modeling in COMSOL Multiphysics with the help of Particle Tracing Module. The aim of this work is to propose adjustments to a model given from COMSOL Application Library that could lead to a functional simple model true to the viscoelastic properties of the environment. Those were controlled through a given script for calculation of MSD in Matlab. The original model was adjusted with the help of rigid obstacles blocking particle transport. Second, rectangular model was also created, where the particle movement had been observed through created channels.
PEG-based semi-interpenetrating polymer network hydrogels
Kadlecová, Michaela ; Kalina, Michal (referee) ; Sedláček, Petr (advisor)
This bachelor's thesis deals with optimization of the preparation of hydrogels based on polymer networks of polyehtylene glycol with the incorporation of a semi-interpenetrating polymer networking and the following chemical-physical characterization of the prepared hydrogels. Polyehtylen glycol diacrylate was chosen from the range of polyethylene glycol modifications as a model material for the formation of hydrogels. Based on this, the preparation using UV photopolymerization was optimized. After optimization of the preparation, selections and following incorporation of the polyelectrolyte took place. Sodium polystyrene sulfonate was chosen as a model polyelectrolyte. Then, there was a basic characterization and comparison of the prepared hydrogels based on polyethylene glycol diacrylate with and without the addition of polyecletrolyte. Swelling, rheology, scanning electron microscopy were used for basic characterization and transport characteristics were investigated using diffusion.
Tailoring transport properties of controlled release systems based on polyhydroxyalkanoates.
Apsalikova, Zarina ; Obruča, Stanislav (referee) ; Sedláček, Petr (advisor)
V rámci předložené práci, polyhydroxyalkanoáty s odlišnými monomerními jednotkami, jako 3-hydroxyvalerát, 4-hydroxyvalerát, 4-hydroxyhexanoát, a 5-hydroxyvalerát byly připravovány za využití bakteriálního kmenu Aneurinibacillus (AH30, AFN2) za účelem porovnání transportních vlastnosti nosičů na bázi izolovaných kopolymerů. Na základě výsledku plynové chromatografii (GC-FID) se ukázalo, izoláty jsou schopné produkovat PHA s různým procentuálním zastoupením monomerů. Dále molekulová hmotnost a index polydispezity izolovaných kopolymerů byly analyzovány pomoci SEC-MALS. Samotné nosičové systémy byly připravovány s využitím izolovaných kopolymerů a komerčního poly(3-hydroxyburyrát). Optimizace byla zaměřena na nastavení podmínek pro tvorbu částic, filmu a porézního systému. Zkoumanými podmínkami byly koncentrace roztoku, množství pomocné látky, a proces izolace nosičů. Vytvořené nosičové systémy byly charakterizovány z pohledu jejich schopnosti uvolňovat aktivní látku (ibuprofen) do modelového prostředí (fosfátový pufr). Na základě provedené charakterizaci bylo stanoveno, že transportní vlastnosti jsou ovlivněny strukturou polymeru a interakcemi v systému polymer-rozpouštědlo. Skenovací elektronová mikroskopie, diferenciální skenovací kalorimetrie, infračervená spektroskopie s Fourierovou transformaci a UV-VIS spektroskopie byly využity jako nástroje pro porovnání a pochopení korespondence mezi chemickou strukturou PHA a jejich transportními vlastnostmi.
The Influence of Biochar Application on the Microbiological Characteristics of Soil
Štorková, Natálie ; Sedláček, Petr (referee) ; Kalina, Michal (advisor)
This diploma thesis is focused on the effect of Pflazenkohle biochar application into the soil and its corresponding microbial characteristics. Along with microbial characteristics (microbial functional diversity, microbial and enzymatic activity), the effect of biochar on soil physicochemical properties (pH, organic matter content, organic C and N content) and plant growth (height, above and below ground dry weight) was also assessed in this thesis. Two types of soils with low organic matter content (sandy arid soils and arenaceous chernozem) were used for the experiments. These soils were obtained after two years of cultivation with biochar at application doses 0 and 20 g-kg-1, maize (Zea mays) was selected as the model plant. The results of the cultivation experiment showed that Pflanzenkohle biochar has the potential to affect soil microbial properties, soil physicochemical properties and also plant growth, but its detectable effects on microbial characteristics of soil were limited. This was probably caused by the inappropriate biochar application form and also by the selection of soil type used for cultivation experiment. To be able to further study the effect of biochar on the soil microbial properties we considered, it would be necessary to modify the setting of cultivation experiments in the way to pronounce the statistically significant differences.
Interactions of pharmaceuticals with fulvic acids – calorimetric study
Papko, Nadezhda ; Sedláček, Petr (referee) ; Klučáková, Martina (advisor)
Tato diplomová práce se zaměřuje na studium interakcí mezi půdní organickou hmotou a vybranými léky pomocí izotermické titrační kalorimetrie. V rámci experimentu byly použity tři fulvinové kyseliny a léky: ibuprofen, diclofenac a sulfapyridine. Vybrané léky a fulvinové kyseliny byly rozpouštěné v roztocích NaCl a MgCl2, jelikož kovové ionty jsou přítomny v organickém materiálu půdy. Mobilita léčiv závisí na sorpci, což je interakce mezi léčivy a půdními částicemi. Faktory ovlivňující sorpční chování zahrnují vlastnosti léčiv, půdy a enviromentální podmínky. Během bakalářské práce podražilo optimalizovat metodu ITC pro daný studiu, což usnadnilo experimentální práce a zlepšilo vyhodnocení dat. Pomocí metody byli stanovené tepelné efekty (naměřené a porovnané) interakcí mezi fulvinovými kyselinami a léky.
Development and experimental evaluation of bioactivity of the next-generation bioinnoculants
Súkeník, Martin ; Pekař, Miloslav (referee) ; Sedláček, Petr (advisor)
This diploma thesis aimed to characterize specific mechanisms of biological activity in plant growth-promoting rhizobacteria (PGPR) commonly found in the rhizosphere of plants and to study the effects of liquid and gel application of PGPR bioinoculants on plants in a controlled environment. An original concept of self-encapsulation via cross-linking of alginate directly produced during their culturing was proposed for the preparation of gel bioinoculants based on these PGPRs. To validate the efficacy of this concept, all selected strains had to be subjected to gelation experiments with the crosslinking agent CaCl2 2 wt. % under alginate gel formation. Three specific strains of Azotobacter vinelandii DSM 87, DSM 720 and CCM 289 were selected for the preparation and characterization of the bioinoculants. The material properties of the formed gels were characterized by oscillatory rheometry (amplitude test). All strains were subjected to gravimetric determination of alginate and biomass concentrations. Flow cytometry with fluorescent probe PI, DAPI and SYTOX™ Green was used to verify cell viability immediately after culturing. Furthermore, the drying of gels was performed using a lyophilizer, where the lyophilized gel was used in swelling experiments followed by drying. To verify the biological activity of the bioinoculants, the ability of all strains to dissolve and utilize phosphate from the agar medium was qualitatively verified. Furthermore, the production of indole-3-acetic acid was spectrophotometrically verified for all strains. The production of siderophores was also verified qualitatively and quantitatively. Cultivation pilot experiments on the lettuce (Lactuca sativa) plant were performed with the addition of both liquid and gel carrier PGPR compositions; as a negative control, the plant was left without the addition of carrier PGPR composition. The results from the pilot growth experiment showed a positive growth effect of both gel and liquid PGPR composition on the plants. At the end of the growing experiment, higher leaf and root system lengths were recorded after the application of both forms of PGPR to the soil, specifically, the average leaf length with the addition of gel carrier PGPR composition was 4.3±1.0 cm and 4.3±1.2 cm for the gel carrier PGPR composition, and the average root system length was 18.3±5.2 cm and 17.4±6.0 cm, respectively. The dry weight per plant grown with the addition of liquid and gel PGPR was the same 0.19±0.07 g. The highest content of chlorophyll a, chlorophyll b and carotenoids in the leaves was spectrophotometrically detected in plants grown with the addition of liquid PGPR composition, specifically chlorophyll a was found to be 6±1 µg/ml, chlorophyll b 7±2 µg/ml and carotenoids 3.6±0.5 µg/ml. The diversity of soil microbiomes collected from the soil without the addition of PGPR composition, with the addition of liquid PGPR composition and with the addition of gel PGPR composition was analysed using BIOLOG EcoPlate™ plates. The diversity of the microbiome was evaluated using the average well colour development, i.e., the AWCD parameter, and the Shannon diversity index, H'. The highest utilization of the widest number of carbon sources on the plate was recorded for the soil microbiome with the addition of the gel PGPR composition. The aforementioned soil microbiome also showed the highest value of the H' index.
Study on metabolism of polyhydroxyalkanoates in selected thermophilic bacteria
Reinohová, Nikola ; Sedláček, Petr (referee) ; Pernicová, Iva (advisor)
This thesis is focused on adaptive evolutionary engineering in the thermophilic bacterium Schlegelella thermodepolymerans M15344. The theoretical part deals with extremophilic microorganisms, biotechnological applications as well as polyhydroxyalkanoates and evolutionary engineering. In this work, adaptation of this microorganism to 40 °C and 60 °C was carried out using glucose and xylose substrates. Furthermore, repeated-batch cultivation at 50 °C on glucose and xylose was performed. In these experiments, the concentration of PHA produced in the biomass was determined by gas chromatography, and the concentration of residual sugars in the medium was determined by a method using DNS. Production of polyhydroxyalkanoates in the adapted strains from each experiment was compared with the non-adapted strain. Subsequently, the PHA produced by individual bacteria was studied using the SEC-MALS method, where the effect of adaptation on molecular weight was observed. The highest producing bacteria was adapted to 40 °C and the substrate was glucose. In this case, the biomass value was 6,74 g/l with a PHA percentage of 56.5 wt%. The bacteria was also adapted to 60 °C where it was able to grow and produce unlike the original bacteria.

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See also: similar author names
1 Sedláček, Patrik
3 Sedláček, Pavel
2 Sedláček, Petr,
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