National Repository of Grey Literature 67 records found  1 - 10nextend  jump to record: Search took 0.00 seconds. 
Influence of plasma activated water on seed germination and quality of corn
Kovařík, Martin ; Zlámalová Gargošová, Helena (referee) ; Kozáková, Zdenka (advisor)
The bachelor's thesis deals with the effect of plasma-activated water on corn germination. After water comes into contact with plasma, the water changes its chemical composition and thus, it acquires new properties that can be used in agriculture. The theoretical part is divided into two basic parts. At the beginning of the first part, plasma is briefly characterized, and then this part deals with plasma-activated water, its formation, physical and chemical properties, and at the end of this part, its use. The second part of the theoretical part is devoted to the germination of plants, external influences affecting germination and statistical evaluation of germination. At the end of the theoretical part, this thesis deals with the ecotoxicity of plants. The content of the experimental part was the preparation of PAW, its subsequent application to corn seeds and the study of its effect on germination and plant quality. PAW was created from distilled or tap water using three different plasma systems and the effect of each PAW on the seeds was compared with that of each control sample. The obtained results indicate a positive effect of PAW on seed germination, but the final hypothesis would require more extensive experiments in different environments, especially in soil.
Influence of plasma activated water on fungal diseases
Moskvina, Anastasia ; Krčma, František (referee) ; Kozáková, Zdenka (advisor)
This bachelor thesis focuses on influence of plasma treated water on fungal diseases. The theoretical part is dedicated to plasma-liquid interactions, properties and application of plasma activated water and its influence on different microorganisms. Plasma activated water contains reactive oxygen species which cause inactivation of living cells, making it a potential sterilizer. The experimental part of this work compares the effectiveness of three plasma treated water preparation techniques. Dielectric barrier discharge system was used to activate water above its surface. For the under the surface activation, a two-electrode system of both alternating and direct current was used. Plasma treated water was then used to prepare a suspended mixture with Aspergillus niger spores. The latter was then cultivated on agar plates for 72 hours. The overall effect was evaluated in amounts of colony forming units. The experimentally obtained data was processed and discussed in the results and discussion section of the thesis. It was found that the underwater surface activation had more significant effect on mold deactivation, which corresponds with the information contained in the theoretical part. Although the effect of dielectric barrier discharge was not as promising, all three methods used led to a decrease of colony forming units in comparison to the non-treated control sample.
Influence of plasma and plasma activated water on fungi Aspergillus niger
Žitný, Michal ; Čechová, Ludmila (referee) ; Kozáková, Zdenka (advisor)
The thesis deals with the issue of decontamination of Aspergillus niger mold using plasma, plasma-activated water and their combination. The theoretical part concerns the effects on the general properties of plasma, its generation, effects on microorganisms known so far and its use in industry with a special focus on medicine. It also focuses on the generation and characterization of plasma-activated water, its effects on bacteria, yeasts and fungi and its use. It also deals with the description of fungi, their occurrence and their sterilization. Part of the theory was aimed directly at the fungus Aspergillus niger. Its cultivation and its industrial uses, such as its use for the cultivation of citric acid, were described here. The experimental part deals with the characterization of plasma-activated water generated using a torch jet. The influence of the supplied power on the formation of particles in plasma-activated water was monitored. The decontamination effect of the plasma, generated by the torch jet, alone and in combination with plasma-activated water generated by alternating and direct current is monitored. The characterization of plasma activated water was performed with 20 ml of distilled water at a carrier gas rate of 2 l/min and a power of a microwave source of 9 and 12 W. The decontamination effect of plasma and its combination with plasma-activated water was observed by inoculating 100 l of a ten-fold and a hundred-fold diluted treated mold culture on Petri dishes with malt agar. The evaluation of the effect was carried out by counting the grown fungal colonies and subsequent comparison with control samples. All measured and obtained data were processed in the results. Plasma activated water generated by the torch jet has been found to contain higher concentrations of nitrogenous substances and lower concentrations of hydrogen peroxide, with the generated nitrate concentrations being higher at lower output than at higher output. DC-generated plasma activated water containing low concentrations of nitrogenous species and a very high concentration of hydrogen peroxide compared to PAW generated by a torch jet. Furthermore, plasma-activated water generated using a high frequency source contains minimal concentrations of nitrogenous substances and slightly elevated concentration of hydrogen peroxide in regard to torch jet PAW. The highest decontamination effect of all the methods used was the combination of plasma and plasma activated water, prepared by a plasma nozzle using direct voltage, when the plasma was applied first. On the contrary, the least effective method was the application of plasma and plasma activated water, generated by high frequency voltage. Limiting oxygen access had almost no effect on direct plasma treatment, but other methods were significantly affected by it. The greatest difference in decontamination effect was observed for the combination of plasma and plasma activated water, generated by high frequency current, where the difference was up to 30 %, but all methods had a significant decontamination effect compared to the control.
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.
Optimization of distribution of active particles generated by low temperature plasma on biopolymer surfaces
Krupičková, Lucie ; Kozáková, Zdenka (referee) ; Krčma, František (advisor)
This thesis is focused on the optimization of the distribution of active particles (RONS), generated by the low temperature plasma, on the biopolymer surfaces. The theoretical part characterizes plasma and its active particles. Furthermore, this chapter summarizes its applications in medicine and food industry, also a review of different skin models is listed here. The last section is focused on the skin anatomy and the characterization of selected microorganisms C. glabrata, E. coli and S. epidermidis. In the experimental part, selected biopolymers with specific dyes for detection of active particles were prepared. Furthermore biopolymers were spot treated under different conditions leading to color changes in all biopolymers. This test confirmed a presence of active particles in the plasma. After that, the optimal parameters for active particles distribution over the entire surface were found. Also an experiment, which allowed the UV light to pass through but prohibited the passage of active particles, was made. In this experiment, no color change was noticed, which means, that the reaction of active particles with the colored biopolymer is responsible for the color change. The optimized parameters were used for treatment of agar plates with monoculture of C. glabrata, E. coli, S. epidermidis and with mixed culture C. glabrata + E. coli. Two different plasma torches were used – unipolar microwave discharge torch and surface wave microwave discharge jet. Treated samples were photographed after incubation. Software Aurora then calculated the surface area which was covered by the microbial culture. Based on the data, the microbial reducion was evaluated in comparison with untreated samples. The unipolar microwave discharge torch achieved higher efficiency than the surface wave microwave discharge jet, for all tested microorganisms.
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.
Study of plasma and plasma activated water effect for bacterial disease treatment
Korečková, Svatava ; Jirásek,, Vít (referee) ; Kozáková, Zdenka (advisor)
The aim of this master thesis was to prepare plasma-treated liquids (PTL), specifically plasma-treated saline solutions, using different plasma systems. Subsequently, PTL was applies onto selected microorganisms to determine its antimicrobial effect. Systems that use both direct and indirect plasma-liquid interactions were selected, and the plasma was generated at atmospheric pressure. The theoretical part is focused on the plasma treated water, the systems by which PTL can be produced, and a description of the characterization process, from the viewpoint of the amount of active particles or the physical-chemical properties. Here, the microbiological part of this work is also included, namely a description of the microorganisms used for the experimental part. The disease of otitis externa (inflammation of the external auditory canal) and the possibilities of its antibiotic treatment are also described here. In this work, PTL prepared by four different plasma systems were tested: the pinhole discharge with DC or AC high voltage source (PTLAC and PTLDC), the liquid electrode dielectric barrier discharge (PTLDBD), and the microwave surface wave discharge (PTLSW). Prepared PTLs were first characterized in terms of reactive particles (hydrogen peroxide, nitrates and nitrites) and changes in specific conductivity and pH. This was followed by microbiological testing of the antimicrobial efficiency of the prepared PTL. The bacteria Staphylococcus pseudintermedius, Pseudomonas aeruginosa and the yeast Malassezia pachydermatis were selected as test microorganisms. These microorganisms were exposed to PTL and the effects were studied for exposure times from 1 minute to 4 hours. After 24 hours of cultivation, the antimicrobial effects were evaluated by the standard plate count method and also by the image analysis method in the software Aurora. The next step was to compile antibiograms and compare the effect of the prepared PTL in different systems with the effect of antibiotics. In this master thesis, it was proven that the bacterium Pseudomonas aeruginosa is resistant to several antibiotics. Thus, the prepared PTLDC could represent the possibility of its inactivation without the use of antibiotics. Staphylococcus pseudintermedius and Malassezia pachydermatis do not have resistance to any antibiotic (antimycotic), but with incorrect use there is a risk of developing resistance, which is why PTL, with the highest antimicrobial effect, were also found for these microorganisms.
Application of plasma and plasma activates water for wound healing
Šrámková, Sarah ; Janda,, Mário (referee) ; Kozáková, Zdenka (advisor)
This work is focused on the study of plasma interactions with liquids and selected microorganisms, Staphylococcus epidermidis and Escherichia coli. The use of the cold atmospheric pressure plasma in the biomedical field has been a hot topic in the last decade, due to its decontamination properties applicable not only in the biomedical field but also in the food industry and agriculture. Recently, the plasma treated (activated) liquids (PTLs) have also been a subject of a great interest due to the relatively simple preparation, the possibility of optimizing the composition of PTLs to achieve the desired effect, their non-toxic nature and their environmental friendliness. The purpose of this work is to study the inhibitory effects of the plasma discharges and the plasma treated liquids for the purpose of decontamination and stimulation of wound healing. To study the effect of a direct plasma application on selected microorganisms, two types of discharges, the unipolar microwave torch and the microwave surface wave jet, were selected. For both selected discharges, the dependence of the inhibitory effects on the treatment time, the power, the closure of the treated area and the bacterial species (gramnegative/grampositive) was studied. Comparable results in the inhibition efficiency were obtained for both discharges. The effect of indirect treatment using plasma-treated water was studied next. A decent microbial reduction occurred for all three studied PTLs. The PTL prepared using a plasma jet with a direct current (DC) source was found to be the most efficient. The last stated goal of this diploma thesis was to study the effect of treatment combinig both the indirect treatment with PTL and the direct plasma treatment. Based on the results of previous treatments, a bacterial culture of Staphylococcus epidermidis was treated with PTL prepared with a direct current (DC) plasma jet. The unipolar microwave torch with a power of 12 W was selected for the direct treatment. By combining both types of treatments, higher inhibition effeciency was achieved. The inhibition efficiency was demonstrated for all types of treatments, with the combined treatment aspiring to be the most effective, as it targets both grampositive and gramnegative bacteria.
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.
Analysis of aromatic compounds in plasma treated onion
Krejsová, Lenka ; Kozáková, Zdenka (referee) ; Krčma, František (advisor)
This bachelor thesis deals with the analysis of fragrances in onions, which were exposed to plasma before planting. The adjustment was made to see if onion growth and yields would improve. The theoretical part deals with the quantitative and qualitative methods for the determination of volatile substances. It contains the principle and instrumentation of mass spectrometry as well as the tandem connection of gas chromatography with mass spectrometry. In the experimental part, a liquid sample was obtained by pressing. After 60 minutes, saturated vapors were analyzed by reactive ionization mass spectrometry (PTR-MS). Thanks to this analysis, the concentration of volatile substances was determined. Some samples were analyzed by gas chromatography with mass spectrometer as detector to identify the compounds, because PTR-MS does not allow distinguishing of isomers. Subsequently, the data were processed and evaluated. From the gathered obtained it is clear that the plasma treatment has an effect on the fragrances concentrations. After six months of storage, the presence of some volatile substances increased due to increased biological activity.

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