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Germicidal effects of corona discharge on microorganisms
Dymáčková, Laura ; Kříha, Vítězslav (advisor) ; Julák, Jaroslav (referee)
This thesis following up the studies about decontamination effects of low-temperature plasma generated by corona discharge. Two species of bacteria, Escherichia coli and Staphylococcus epidermidis, were exposed in two separate sets of experiments. Bacterial suspensions were treated by point-to-plane corona discharge directly on surface of semisolid culture medium, the Mueller-Hinton agar, placed in Petri Dishes of 5 cm diameter. The point electrode was realized by the tip of a 0.7 mm syringe needle, connected to the source of direct current high voltage. The plane electrode was formed by the surface of an ion-conducting semisolid cultivation medium. A micrometer screw allowed precise setting the 4 mm distance of the point electrode from the anode surface. The samples were exposed to the corona discharge with current of 25μA - 150μA range. The treatment duration is given by constant exposed charge (18, 27, 36 and 54 mC) condition. After exposition, all Petri dishes were immediately cultivated at 37 žC overnight. After cultivation followed evaluation of inhibition zone areas, that was caused by action of electric charge. The state of the cultures was quantitatively assessed by measuring of the growth inhibition zones, where a complete growth inhibition took place. The behaviors of these exposures were...
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Effect of various plasma sources on seed growth. Laboratory experimen in Buckwheat
Šerá, Božena ; Gajdová, Iveta ; Čermák, M. ; Gavril, B. ; Hnatiuc, E. ; Kováčik, D. ; Kříha, V. ; Sláma, J. ; Šerý, M. ; Špatenka, P.
Germination and early growth of buckwheat (Fagopyrum aesculentum) after low-temperature plasma discharge treatment in air gas generated in various apparatus were tested. Three pretreatment times were used: 180 s, 300 s and 600 s. Number of germinating achene, length and weight of sprouts were measured. The data was analysed with two-way ANOVA. A significant influence of the type of plasma apparatus, time of exposure and combination of both factors were found. The positive effect on germination and early growth was observed after application of GlidArc plasma. The opposite effect of PDBV apparatus, which is characterized by plasma with a high power density, was observed. Shorter pre-treatment times for this apparatus must be therefore used.
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