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Diagnostics of Diaphragm Discharge in Water Solutions and its Application for the Nanomaterials Surface Treatment
Dřímalková, Lucie ; Brablec, Antonín (referee) ; Janda,, Mário (referee) ; Krčma, František (advisor)
The exact mechanism of the discharge in liquids ignition is not sufficiently known up to now. Although during the last years was achieved the great progress and overloading which some of them are written in this theoretical part of thesis. This thesis is divided into two experimental parts. When the first part deals with diagnostics of diaphragm discharge in electrolyte solutions and the second part is focused on its use for uncoiling (higher homogenization) of carbon nanotubes in solutions. In experiment 1, three different sized (4 l, 100 ml, 50 ml) diaphragm discharge configurations were used to diagnose diaphragm discharge in electrolyte solutions. Diagnostics is done through current and voltage waveforms with the addition of synchronized ICCD camera images that have been connected to a four-channel oscilloscope. The V-A characteristic can be described by three events occurring in the electrolyte solution with a gradual increase in voltage. Slowly increasing of the voltage in the solution leads first to electrolysis. The next phase is the formation of microbubbles or bubbles, which is characteristic of the curve by a slight decrease in the increase of the current passing between electrodes. The sudden increase in the current flow is characteristic of the last phase, namely the discharge phase. The distance of the electrodes from the diaphragm does not significantly affect the V-A characteristic. The higher diameter of the pin hole, therefore, has a higher voltage, but this does not affect the origin of bubble generation or breakdown. The higher thickness of diaphragm, the higher voltage is needed to the beginning of the bubbles generation, and consequently the discharge breakdown. Comparison of the voltage of the start generation of the bubbles and breakdown for PET diaphragms and diaphragms from the ceramic there was no mark able difference. One of the most important parameters is the conductivity of the electrolyte solution. The lower voltage is needed for the start generation of the bubbles at the higher solution conductivity, and also the discharge generation is observed at a lower breakdown voltage. The second experimental part is focused on the study of the diaphragm discharge effect on carbon nanotubes. A specially designed U-shaped reactor is used to modify carbon nanoparticles. Tap water and aqueous solutions of organic compounds are used as the electrolytic solutions. The discharge is generated by a non-pulsed DC high source with a voltage in the range of 0-2.8 kV supplied to platinum electrodes located in the electrolyte solution. The experimental results have shown that the diaphragm discharge has positive effects on the disintegration of clusters and agglomerates of carbon nanotubes. The primary effect on disintegration is probably the shock waves generated by the discharge. It turned out that it depends on the electrode configuration, where the treatment in anode space has far greater effects than the treatment in cathode half of the reactor. Effects of carbon nanotubes disintegration in solution are long-lasting and the treatment effect is not loosed after several months. There were detected no significant changes in the structure of plasma-treated nanotubes by Infra-red spectroscopy.
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The Effect of temperature treatment TiO2 nanoparticles on antibacterial properties
Bytesnikova, Z. ; Valeckova, V. ; Švec, P. ; Richtera, L. ; Šmerková, K. ; Vítek, Petr ; Adam, V.
The synthesis of TiO2 nanoparticles (NPs) under various temperature treatments was described and TiO2 NPs was subsequently tested as an antibacterial agent. Scanning electron microscopy (SEM), Raman spectroscopy, Dynamic light scattering (DLS) were used to confirm structure of TiO2 NPs and detect differences between individual batches treated with different temperature. Antibacterial properties were tested on Escherichia coli (E. coli). TiO2 NPs as photocatalyst was incubated with bacterial cells under ambient light. Changes in temperature treatment can affect diameter size and crystal structure of TiO2 NPs as well as its antibacterial properties.
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Polymer probes for photodynamic therapy of solid tumors
Kotalík, Kevin ; Etrych, Tomáš (advisor) ; Kovář, Marek (referee)
One of the currently studied promising strategies in advanced oncologic treatment is photodynamic therapy, a method based on the administration of so-called photosensitisers, i.e. photoactive compounds such as porphyrins, and subsequent irradiation of tumor tissue with light of appropriate wavelength. An excitation of the photosensitiser, present in the tumor area, is hence invoked and reactive oxygen species (ROS) are formed. These species afterward cause the apoptosis of the tumor cells, leading to destruction of tumor tissue. In photodynamic therapy, the strategy of administration of a prodrug which is metabolised to the active photosensitiser can be used with advantages. In photodynamic therapy, this prodrug may be 5-aminolevulinic acid (5-ALA) or its esters which are metabolised to protoporphyrin IX (PPIX), the photosensitiser proper. The targeted drug delivery to the tumor tissue can be achieved by using various delivery systems, e.g. water-soluble polymer conjugates carrying the drug. Due to their size, these polymer conjugates are accumulated in solid tumors on the basis of the enhanced permeability and retention (EPR) effect. Macromolecules can penetrate the tumor vasculature, which, unlike that of healthy tissue, is imperfectly developed and contains gaps between endothelial cells....
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Polymer probes for guided endoscopic surgery of solid tumors
Horák, Dominik ; Etrych, Tomáš (advisor) ; Bouček, Jan (referee)
1 Abstract: This work focuses on development of both low- and high-molecular substances usable in fluorescent navigated endoscopic surgery with an emphasis on the characteristics of both tumor tissue and the substance itself. The usage of low-molecular substances, such as indocyanine green, has been abandoned over the past years, mostly due to poor localization and short circulation time. New polymer probes such as those based on pHPMA, were introduced to resolve these flaws. They benefit from the enhanced permeability and retention effect of the tumor tissue which is specific for macromolecules. The attachment of fluorophores to polymer carriers induces quenching, therefore novel systems are being designed to be able to release the fluorophore for example due to acidic environment of a tumor tissue or the overexpression of some peptidases. The experimental part of this work is dedicated to such polymer system with a pH-sensitive spacer-bound fluorophore. Keywords: polymer probes, fluorescence, pH-sensitive, nanomaterials, controlled release, quenching, Cyanine7 [IN CZECH]
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Biocompatible polymer nanomaterials with non-steroid drugs tailored for anti-inflammation therapy
Běhalová, Kateřina ; Etrych, Tomáš (advisor) ; Kovář, Marek (referee)
The main aim of this bachelor thesis was synthesis and physico-chemical and preliminary biological characterization of water-soluble biocompatible polymeric system for targeted delivery of acetylsalicylic acid to inflamed tissue. Such polymer conjugates should be employed in the future for the therapeutic use within the treatment of chronic inflammatory diseases. The project included the preparation of a series of suitable acetylsalicylic acid derivatives and the synthesis of a polymeric carrier based on N-(2-hydroxypropyl) methacrylamide copolymer. Finally, the acetylsalicylic acid derivative was attached to the polymer forming a polymeric conjugate with pH-sensitive bond between the drug derivative and polymer chain, thus allowing controlled release of the drug in the target site. The work includes SEC, NMR and HPLC characterization of all synthesized compounds, verification of their stability in solutions with different pH and results of the release of drug derivatives from the polymeric carrier at physiological pH, or mildly acidic pH modeling inflamed environment. Moreover, the cytotoxicity bioassay of acetylsalicylic acid derivatives using LDH assay did not prove any cytoxicity at the level of necrotic activity. Also, their cyclooxygenase 1 inhibitory activity was observed and discussed. The polymeric...
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Biocompatible polymer nanomaterials with dexamethasone tailored for anti-inflammation therapy
Starenko, Daniil ; Etrych, Tomáš (advisor) ; Indra, Radek (referee)
Chronic inflammatory diseases are very common and affect lives of many people around the world. Moreover, in long-term effect chronic inflammation can lead to the development of such complications as diabetes, atherosclerosis and oncological diseases. Temporary therapy does not lead to complete recovery of a patient, but can provide a relief of symptoms by means of immunosuppression, which causes many adverse effects, because of long-term and nonselective drug activity. Application of the polymeric drug delivery systems is one of the actively researched ways for the improvement of inflammatory diseases treatment quality, which enables longer circulation, better distribution and controlled release of the drug. Dexamethasone is one of the commonly used glucocorticoid drugs used for treatment of chronic inflammatory diseases. Properties of this drug can be enhanced via polymeric drug delivery systems. Recently, so-called biological treatment, particularly employing monoclonal antibodies, against inflammation was introduced into the clinical use. One of such is infliximab - chimeric monoclonal antibody, which acts like the inhibitor of tumor necrotizing factor α (TNF-α). Presented bachelor thesis focuses on the synthesis and characterization of a polymer conjugates based on...
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Biodegradable polymer carriers with structure tailored for increased tumor tissue permeability
Hrochová, Michaela ; Etrych, Tomáš (advisor) ; Sedláček, Ondřej (referee)
Cancer diseases are the most common cause of death over the world. One fifth of death is caused by cancer in the Czech Republic. The big problem in the treatment of cancer diseases are side effects of chemotherapy, which make treatment more difficult for patients. The present bachelor thesis is focused on synthesis and characterization of novel polymer carriers. Polymer carriers can target the cytostatic drug to the tumor tissue and minimize side-effect of chemotherapies. This bachelor thesis is focused on synthesis and physical chemistry characterization of new diblock polymer carriers, specifically carries of docetaxel. Successful synthesis of novel water-soluble polymer precursors and conjugates based on N-(2-hydroxypropyl)- methacrylamide is described and discussed in this thesis. The hydrolytic stability of the synthesized diblock systems was studied in 0,3M phosphate buffer at pH 7,4 simulating the bloodstream environment. It has been successfully verified that the synthesized polymer systems are hydrolytically degradable after fulfilling its role of drug carrier and therefore can be finally excreted from the organism. The effect of the type of oxoacid used for modification of the cytostatic on the release rate of the carried cytostatic from the polymeric carriers was thoroughly evaluated and...
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Diagnostics of Diaphragm Discharge in Water Solutions and its Application for the Nanomaterials Surface Treatment
Dřímalková, Lucie ; Brablec, Antonín (referee) ; Janda,, Mário (referee) ; Krčma, František (advisor)
The exact mechanism of the discharge in liquids ignition is not sufficiently known up to now. Although during the last years was achieved the great progress and overloading which some of them are written in this theoretical part of thesis. This thesis is divided into two experimental parts. When the first part deals with diagnostics of diaphragm discharge in electrolyte solutions and the second part is focused on its use for uncoiling (higher homogenization) of carbon nanotubes in solutions. In experiment 1, three different sized (4 l, 100 ml, 50 ml) diaphragm discharge configurations were used to diagnose diaphragm discharge in electrolyte solutions. Diagnostics is done through current and voltage waveforms with the addition of synchronized ICCD camera images that have been connected to a four-channel oscilloscope. The V-A characteristic can be described by three events occurring in the electrolyte solution with a gradual increase in voltage. Slowly increasing of the voltage in the solution leads first to electrolysis. The next phase is the formation of microbubbles or bubbles, which is characteristic of the curve by a slight decrease in the increase of the current passing between electrodes. The sudden increase in the current flow is characteristic of the last phase, namely the discharge phase. The distance of the electrodes from the diaphragm does not significantly affect the V-A characteristic. The higher diameter of the pin hole, therefore, has a higher voltage, but this does not affect the origin of bubble generation or breakdown. The higher thickness of diaphragm, the higher voltage is needed to the beginning of the bubbles generation, and consequently the discharge breakdown. Comparison of the voltage of the start generation of the bubbles and breakdown for PET diaphragms and diaphragms from the ceramic there was no mark able difference. One of the most important parameters is the conductivity of the electrolyte solution. The lower voltage is needed for the start generation of the bubbles at the higher solution conductivity, and also the discharge generation is observed at a lower breakdown voltage. The second experimental part is focused on the study of the diaphragm discharge effect on carbon nanotubes. A specially designed U-shaped reactor is used to modify carbon nanoparticles. Tap water and aqueous solutions of organic compounds are used as the electrolytic solutions. The discharge is generated by a non-pulsed DC high source with a voltage in the range of 0-2.8 kV supplied to platinum electrodes located in the electrolyte solution. The experimental results have shown that the diaphragm discharge has positive effects on the disintegration of clusters and agglomerates of carbon nanotubes. The primary effect on disintegration is probably the shock waves generated by the discharge. It turned out that it depends on the electrode configuration, where the treatment in anode space has far greater effects than the treatment in cathode half of the reactor. Effects of carbon nanotubes disintegration in solution are long-lasting and the treatment effect is not loosed after several months. There were detected no significant changes in the structure of plasma-treated nanotubes by Infra-red spectroscopy.
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Results of nanomaterials testing for skin wounds nursing
Juhás, Štefan ; Juhásová, Jana
Using minipigs experiments, we tested the healing of fresh wounds treated with different nanofibrous materials and compared them with standard treatment. From predefined wounds, samples were taken at regular intervals for histological analysis, microbiology, wound measurements and photodocumentation. Blood was also collected from the miniprasate to determine pro-inflammatory cytokines.
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