|
|
Transport of humic substances into leafs
Žáková, Michaela ; Kalina, Michal (referee) ; Klučáková, Martina (advisor)
This bachelor thesis simulates leaf foliar fertilization and describes transport processes of humic substances. Experiments were performed for two areas. The first focused on the flow through the plant cuticle as the main selective barrier. In the second one the transport of humic substances to the leaf was studied. The diffusion process was evaluated by the concentration loss of lignohumate solutions, which served as the medium of humic substances in the solution - leaf model. The results showed the effect of cuticle on nutrient penetration and its dependence on its condition. New findings are the transfer processes of humic substances into the leaves, that have proved effective in a short period of time, mainly at higher concentrations.
|
|
|
Derivatization of Sodium Hyaluronate as a Possible Tool for Increasing of the Stability of Model Artificial Synovial Fluid
Hrochová, Eliška ; Mravec, Filip (referee) ; Kalina, Michal (advisor)
This master thesis deals with the optimization of the procedure of modification of hyaluronic acid structure for the use in the artificial synovial liquids. Based on the literature research, the amino acid alanine was used for the modification of carboxylic group in the glucuronic acid. The main subject of study is the improvement of the stability and mechanical properties of synovial liquid. DLS microrheology, macrorheology, thermogravimetric analysis (TGA), multi-angle light scattering with flow-field flow fractionation (AF4-MALS) and infrared spectroscopy (FTIR) were used for characterization. The theoretical part of this theses submits review of the musculoskeletal system, role of hyaluronic acid in metabolism and summary of synovial liquid. The experimental part focuses on the measurement of the stability and mechanical properties of three artificial samples (first with no modification, second with modified hyaluronic acid and third with modified hyaluronic acid and chondroitin sulphate). These samples were compared with real horse synovial fluid and artificial viscosupplement Orthovisc®.
|
|
|
Utilization of light scattering techniques in study on protein denaturation
Köbölová, Klaudia ; Kalina, Michal (referee) ; Sedláček, Petr (advisor)
This bachelor thesis is focused on verifying the use of light scattering techniques in the study of protein denaturation. The theoretical part of the thesis describes proteins, their general properties, the process of denaturation and it provides an insight into light scattering. In the experimental part of the study I investigated the denaturation effects of four selected potential denaturing agents – urea, guanidine hydrochloride, sodium dodecyl sulfate, copper (II) sulfate – on two model enzymes: lipase and lysosyme. The denaturation effects of these denaturants were studied with the help of the dynamic light scattering method (DLS). In order to describe the change in particle size during denaturation, I used Z-Average, Volume mean and intensity distribution which were determined by this method.
|
|
|
Influence of conditions on hydrogel preparation
Heger, Richard ; Kalina, Michal (referee) ; Mravec, Filip (advisor)
This work is focused on testing the influence of conditions, more precisely pH, during the creation of hydrogels that were prepared through the hydration of powdery mixtures, by another name solid-mixture way. The hydrogel system was made from a polyelectrolyte, more accurately sodium hyaluronate and a cationic surfactant, CTAB. The influence of pH was studied through observation and rheology. For measuring purposes, the hyaluronan with the molecular weight of 600-800 kDa was used. The system was examined via a series of buffers with the pH of 3,5-11. The gels were dyed by Sudan III for better observability and description. It was found that the best way of adding an active substance was by adding a dye directly into a powdery mixture. The observed properties of the gels didn’t change even after the gels were modified to the ionic strength of a physiological saline solution (0,15 M).
|
|
|
Study of interactions of pigments with biopolymer chitosan
Kolesa, Pavel ; Kalina, Michal (referee) ; Klučáková, Martina (advisor)
This master's thesis was focused on the study of interaction of some organic azo dyes (model diffusion probes) with cationic biopolymer chitosan. This interactions were realized via diffusion processes in hydrogel media based on thermoreversible agarose. The main aim was study of influence of pH of solution on the diffusion process. Interactions of used dyes are based on electrostatic character. The aminogroup of chitosan interacts with the functional group of chosen dyes (anionic sulfonic group) and thus affects the process of diffusion. The model diffusion compounds were chosen organic anionic dyes Chicago sky blue 6B (C.I. 24 410), Sirius red (C.I. 35 780) and Reactive blue 49 (C.I. 621 526). The important content of this diffusion method is a monitoring of the time progression of diffusion profile by UV-VIS spectrophotometry. The presented work follows the bachelor thesis and shows comprehensive view of the reactivity of chitosan and its behavior in different systems. Unsteady diffusion in cuvettes appears to be a universal method for the study of reactivity of biopolymers and for the study of transport processes in hydrogel media. The diffusion method is universal, easy and cheap.
|
|
|
Study on Interconnection between Structure and Rheological Properties of Hydrogels on Macro and Microscopic Level
Lepíková, Jana ; Klučáková, Martina (referee) ; Kalina, Michal (advisor)
Diploma thesis main goal is to obtain new pieces of knowledge about relationship between hydrogel structures and its flow and transport properties. Thesis is mainly focusing on combining pertinent biopolymers into model hydrogels based on agarose. Then perform correlation of results obtained by diffusion methods, and by rheologic measurements on macroscopic and microscopic level. Properties of hydrogels were measured by selected rheologic measurements, dynamic light scattering method, and correlative fluorescence spectroscopy. From these methods various parameters (MSD modules, values of complex viscosity) were obtained. Afterwards transport properties of prepared hydrogels were studied by observing Rhodamine 6G diffusion. Here two different approaches were used. From macroscopic perspective, simple principles of mass diffusion from dye solution to cuvettes filled with hydrogels containing individual biopolymers were used. From microscopic perspective, dye was added during the sample preparation and then the mass diffusion was investigated using FCS. Based on evaluated results it was discovered that added biopolymers don’t influence properties of carrier medium, in this case agarose hydrogels. During the study of prepared hydrogels’ reactivity and barrier properties some differences were observed. Charge of biopolymer and its charge density were discovered as main factors influencing transport of charged solutes into prepared hydrogels.
|
|
|
Behaviour of diclofenac in soil systems
Šmerdová, Kateřina ; Kalina, Michal (referee) ; Klučáková, Martina (advisor)
In these days, a large amount of drugs are not completely removed in wastewater treatment plants, than it enters watercourses and then it leaks into soils. These substances are not natural in the environment, so they can have a negative effects here. This is very important to study the behavior of foreign substances in the environment. In this thesis the sorption and desorption behavior of the commonly used drug diclofenac in the soil system was monitored. The rate of sorption and desorption was determined from the change in diclofenac concentration analyzed by UV-VIS spectrometry. Changes in pH and conductivity were also monitored. Diclofenac showed good sorption properties in all the concentrations. There was no desorption or just a minimal desorption, that indicating a strong bond between diclofenac and soil and less leachability into the soil fusion. The results of this thesis showed, that even if diclofenac leaks into the environment, it is mostly adsorbed into the soil. This is largely positive, because diclofenac is practically harmless in the soil and due to the strong bond it also persist there.
|
|
|
Crystallization of microbial polyesters - methods and biological consequences
Liczka, Jan ; Kalina, Michal (referee) ; Sedláček, Petr (advisor)
The aim of this bachelor thesis was to test suitable methods for preparation of amorphous form of microbial polyesters and to perform model experiment to study a kinetics of crystallization of prepared polyesters. The theoretical part deals with PHA characteristics and various methods of isolating PHB granules from bacterial cells. In the experimental part, measuring techniques such as analytical centrifugation, dynamic light scattering (DLS) and Fourier transform infrared spectroscopy (FTIR) were tested to characterize the properties of PHB granules. Furthermore, an experiment was performed to isolate native PHB granules from Cupriavidus necator using lysozyme, deoxyribonuclease and cell disruption by ultrasonification. The results of the analyzes showed that the granules were either isolated amorphous only in the wet and crystallized upon drying, or that the granules were completely amorphous but not isolated from the bacterial cell.
|
|
|
Study on the Mobility of Selected Representatives of Pharmaceuticals in Natural Systems
Bednárová, Paula ; Pořízka, Jaromír (referee) ; Kalina, Michal (advisor)
This diploma thesis focuses on interactions of chosen pharmaceuticals with soil and study their mobility. First part is devoted to the characteristics of the most common pharmaceuticals that appear in the environment, specifically antibacterial chemoterapeutics and analgetics. Subsequently, the occurrence of the pharmaceuticals in environment, their sources and effects are described. Further, the work focuses on soil components and soil organic matter. In conclusion of the theoretical part is the description of used analytical method for processing of the results and also the current state of the problematics. In the practical part of the thesis the experiments were made and analyzed and further served for better understanding of adsorption and interactions of chosen pharmaceuticals with soil and humin acids as the main reactive part of the soil.
|
|
|
Study and characterization of organic substances in a biochar sample
Vojáčková, Beáta ; Kalina, Michal (referee) ; Enev, Vojtěch (advisor)
This bachelor thesis characterizes biochar from a physico-chemical point of view. The theoretical part deals with biochar as a soil conditioner, its properties, use, production, and last but not least, effect of its sorroundings. For better characterization of organic and inorganic matter a phosphate buffer was used. This buffer ensures their specific extraction due to a neutral pH. The second path is to use rainwater, which simulates the condition of the soil environment. In the experimental part are discussed both; purified buffer-extracted samples and rainwater samples, which were studied by thermogravimetric analysis (TGA), elemental analysis (EA) and by infrared spectroscopy with Fouier transform (FTIR-ATR). Conductivity and pH were also measured. Moisture and ash content, which represent the inorganic non-combustible fraction, were determined using thermogravimetry. The extraction yields were converted to ashless wt. % based on these values. Results of EA provided us with information on the content of biogenic elements and basic physico-chemical characteristics of biochar. In contrast, the FTIR method defined the presence of individual functional groups and specific constitutive units, which are present in the extracts. This information allows us to better understand the environmental impact of biochar on the soil ecosystem.
|
guest ::
RSS feed.