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Characterization of microwave plasma jet generated in argon-nitrogen mixtures
Truchlá, Darina ; Mazánková, Věra (referee) ; Krčma, František (advisor)
This thesis is concerned with influence of nitrogen admixture to non-thermal microwave plasma jet generated in argon flow at atmospheric pressure. Non-thermal plasma can be used in more biomedical applications such cancer treatment, blood coagulation, sterilization etc. It is necessary to know the changes of plasma composition and its parameters in dependence nitrogen concentration to avoid potentional damages of the treated tissue. Plasma jet was characterized by optical emission spectroscopy along its axis. Electron, vibrational and rotational temperatures were calculated from intensities of the selected spectral lines and bands emitted by particles generated in plasma. The results show increase of the nitric oxide concentration followed by the increase UVC radiation. Temperature of the neutral gas increase too, but not so much and thus jet with nitrogen addition can be still used for the treatment of thermosensitive materials such as human tissue. Study of the sterilization effect of microwave plasma generated in argon-nitrogen mixtures is still under progress. Some of the results obtained during this thesis were included in the paper submitted into Journal of Physics D: Applied Physics.
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Characterization and application of microwave plasma on wound healing
Smejkalová, Kateřina ; Skoumalová, Petra (referee) ; Krčma, František (advisor)
The aim of the Master thesis is the investigation of the influence of microwave discharge for skin wound healing. Microwave discharge used for this work was argon microwave plasma generated by the surface wave and direct vortex torch. The theoretical part is focused on basic information about plasma and processes that occur in plasma discharge under specific conditions. Plasma generates various active particles such as hydroxyl radicals, nitric oxide radicals, excited nitrogen molecules, atomic nitrogen, argon and oxygen. All of these particles together with plasma generated photons are usable in biomedical applications and summary of them is shown in the theoretical part. The experimental part is focused on the comparison of torch discharge and microwave plasma generated surface wave in skin wound healing. The model wounds on laboratory mousses were treated by plasma and wound healing was examined during 3 weeks after the plasma treatment. Both plasma systems showed healing acceleration. Application of torch discharge was proved to be the most effective method in the healing of skin defects. Additionally, determination of active particles was taken by optical emission spectroscopy. Based on these measurements, plasma parameters were determined: electron temparutare, rotational and vibrational temperatures. To determine role of different plasma active species, the treatment of indigo coloured artificial skin model was treated under various conditions by both plasma systems. Results show that the direct interaction between plasma particles is the main effect, role of radiation, only, is more or less negligible. Finally, the plasma vortex system was visualized using fast camera at selected powers and gas flows.
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Study of plasma interaction with bacteria for cosmetic applications
Kocianová, Magdaléna ; Krčma, František (referee) ; Kozáková, Zdenka (advisor)
This bachelor thesis is focused on sterilization effects of low temperature plasma on grampositive, anaerobic non-sporulating bacteria Propionibacterium acnes. The plasma sterilization process is fast, effective, non-toxic, environmentally friendly, cost- effective and safe not only for servicing staff, but mainly for the patient. Another advantage of using low temperature plasma is the promotion of cell proliferation and wound healing. The experimental part is conducted to provide an inhibition effect of low-temperature plasma on the Propionibacterium acnes bacterium that causes a purulent inflammation. This bacteria was inoculated in various concentrations on culture soil and treated by plasma at a distance of 1 mm from the agar surface. Two plasma devices were used for plasma generation. One of them was a traditional torch discharge, the second one was based on the surface wave discharge. The microwave discharge was generated in argon at a power of 9 W, gas flow rate of 5 l/min and with water cooling to avoid thermal effects on the treated surface. From the achieved results it can be stated that the low temperature plasma has sterilization effects on a grampositive, anaerobic non-sporulating bacteriu Propionibacterium acnes.
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Comparison of plasma activated water quality prepared by different plasma systems
Staškovanová, Denisa ; Krčma, František (referee) ; Kozáková, Zdenka (advisor)
This diploma thesis deals with generation of reactive species (hydrogen peroxide, nitrates, nitrites) using various plasma systems in distilled and tap water. Prepared plasma activated water differs in the way the plasma is applied, namely plasma above the water surface, plasma inside water or bubbling of plasma gaseous products into water. The main goal is to determine the amount of species produced in different plasma systems and compare them with each other. The effect of ozonizer experimental conditions on the generated amount of reactive species is also monitored.
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Diagnostics of active particles generated by the interaction of plasma microwave discharge with liquids
Kovaříková, Kateřina ; Töröková, Lucie (referee) ; Kozáková, Zdenka (advisor)
The first part of this Bachelor’s thesis describes problems of electric discharges in gas and on a surface of water solutions. It focuses on the generation of the active particles that are generated during the discharge and their subsequent analysis by appropriate analytical methods. The second part focuses on identification of the active particles that are generated during the microwave discharge in gas phase and during the interaction with water solution surface. The aim is to determine the influence of experimental conditions on the information of the active particles, specifically the nitrates and nitrite ions.
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Characterization of microwave plasma jet generated in argon-oxygen mixtures
Smejkalová, Kateřina ; Mazánková, Věra (referee) ; Krčma, František (advisor)
The optical diagnostics of microwave plasma torch operating at the frequency of 2,45 GHz is a subject of this bachelor thesis. Microwave plasma is generated using the surfatron resonator in argon with oxygen admixture (up to 1,7 %) at the constant argon flow of 3 Slm. The theoretical part gives the basic information about plasma and processes running under plasma conditions. Various active particles such as hydroxyl radicals, nitric oxides, excited nitrogen molecules, nitrogen, argon and oxygen atoms are generated in the discharge. All these particles together with the plasma generated photons can be used in biomedical applications that are briefly reviewed in the theoretical part, too. The visual observation of oxygen admixture on the discharge and the optical emission spectroscopy based determination of the active particles presence along the discharge and post-discharge axis is the subject of experimental part. Based on it, the selected plasma parameters like electron, rotational and vibrational temperatures were calculated.
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Use of plasma jet for biomedical application
Doubravová, Anna ; Márová, Ivana (referee) ; Skoumalová, Petra (advisor)
This master´s thesis is focused on the utilization of the sterilization effects of low temperature plasma towards the bacterial microorganisms that occur mainly on the human skin. The plasma sterilization process is fast efficient, non-toxic, environmentally friendly, cost-effective and safe for the operating staff as well as for the patient. Another advantage of using low temperature plasma is to support cell proliferation and wound healing. By combining these advantages, an effective method can be obtained, which would sterilize the wounds sparingly with regard to the surrounding healthy tissue and support the regeneration of the damaged tissue at the same time. In the experimental part, gram positive and gram negative bacteria were used to prove the sterilization effects with respect to different cell wall structure. Staphylococcus epidermidis and Propionibacterium acnes, which cause purulent skin inflammations, were used as gram-positive microorganisms. Serratia marcescens and Escherichia coli were selected from gram positive bacteria. These model organisms were inoculated at various concentrations on culture broths and treated by plasma at a distance of 1 mm from the agar surface. The microwave discharge was generated in argon at a power of 9 W, a gas flow rate of 5 l / min and water cooling to avoid thermal effects on the treated surface. Subsequently, model skin cells of HaCaT were exposed to low temperature plasma and tested for plasma cytotoxicity to demonstrate its healing effects. The obtained results make it possible to state that the sterilizing effects of low-temperature plasma in all tested gram-positive and gram-negative bacterial strains are verified in this work. Finally, tests were demonstrated using a suitable method of the treatment on human skin cells, where the safety and usefulness of the tested low-temperature plasma was demonstrated when applied to shorten the healing process.
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Comparison of organic dye decomposition in various plasma systems
Dotsenko, Anastasia ; Králová, Marcela (referee) ; Kozáková, Zdenka (advisor)
This bachelor thesis deals with the comparison of the degradation of organic dyes (namely: Saturn Red L4B (Direct Red 79) and Indigo Carmine (Acid Blue 74)) in different plasma systems and the general characteristics of the optical emission spectrometry of a microwave plasma nozzle. It briefly summarizes basic information about plasmas and the processes involved. The theoretical part focuses on basic information about plasmas and their processes, basic information about dyes and their degradation methods. Plasma contains a number of active particles such as hydroxyl radicals, nitrogen oxide radicals, excited nitrogen molecules, atomic nitrogen, argon and oxygen. All these particles, together with photons generated by the plasma, are useful in environmental applications. The experimental part focuses on treating a sample of model dyes in selected plasma systems generating plasma above the liquid surface (microwave surface wave discharge, dielectric barrier discharge with liquid electrode) or below it (plasma nozzle in liquid) and evaluating their decomposition rate. Characterization of the distribution of active particles along the plasma axis of a high frequency plasma jet in argon and determination of the conditions in the plasma with respect to the environmental applicability of the system.
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Study of decontamination effects of plasma and plasma activated water
Kovaříková, Kateřina ; Krouská, Jitka (referee) ; Kozáková, Zdenka (advisor)
The theoretical part of this Diploma’s thesis describes the use of plasma in decontamination processes. The experimental part of the thesis focuses on the preparation and characterization of model samples of organic dyes by appropriate analytical methods. The model samples were treated by direct exposure to plasma or plasma activated water. For both treatments, two different plasma sources were used - a dielectric barrier discharge in an ozonizer with subsequent bubbling of its gaseous products into the solution, and a microwave plasma jet applied to the liquid surface. The aim of the work was to evaluate the decontamination rate of the samples and to compare the performance of the different systems.
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Application of plasma and plasma activated water in cosmetics
Kocianová, Magdaléna ; Tarabová,, Barbora (referee) ; Kozáková, Zdenka (advisor)
This diploma thesis is focused on the study of the inhibitory effects of the cold atmospheric pressure plasma on the grampositive, anaerobic, non-sporulating bacteria Propionibacterium acnes. The treatment was carried out by a direct application of plasma, indirectly (using plasma-treated liquids) and also in their combination. The plasma sterilization process is fast, effective, non-toxic, environmentally friendly, cost-effective and safe not only for the operating staff, but especially for the patient. The experimental part focuses on the study of the direct application of plasma. Two plasma devices for the generation of microwave plasma were used. One of them was a unipolar microwave discharge torch with direct gas supply and the other was a microwave discharge with a surface wave. Discharges were generated in argon with a flow rate of 5 Slm, at a power of 9 W and 12 W. The work also deals with the indirect treatment using plasma-treated liquids. These were prepared using the pinhole discharge and the dielectric barrier discharge. In the last part, combined treatment using plasma-treated liquid and direct plasma treatment was studied. From the achieved results, it can be concluded that the sterilization effects of the plasma and the plasma-treated liquids on the Propionibacterium acnes were confirmed.
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