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Characterization of programmed cell death during lyzigenous aerenchyma formation
Lenochová, Zuzana ; Votrubová, Olga (advisor) ; Čiamporová, Milada (referee) ; Kummerová, Marie (referee)
Abstract____________________________________________________________________ 2 ABSTRACT: Zea mays is generally considered to be a plant with inducible lysigenous aerenchyma formation. The degradation of some cortical cells is triggered by environmental conditions, usually in the form of stress (submergence etc.). These cells die in a process that shows signs characteristic for programmed cell death, such as nuclear DNA fragmentation or apoptotic ultrastructural alterations. Aerenchyma formed in primary roots of thirteen examined maize accessions, irrespective of cultivation conditions. The aerenchyma fraction correlated with the root length, not with its age. The dependence of aerenchyma formation on the presence of this phytohormone was proved by using an inhibitor of ethylene synthesis (AOA). It was found out that the aerenchyma formation depended on light conditions and that the lysigenous intercellulars intercellular spaces colocalized with areas with cells with characteristically fragmented nuclear DNA (TUNEL-positive nuclei). In experiments using the TUNEL reaction it was necessary to determine new dilution of the enzymatic mixture for the examined plant material. Only the observation of surface planes of free-hand root sections was considered relevant in both TUNEL-TMR and TUNEL-AP assays. TUNEL-AP...
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Implementation of laser technology
Urban, Jan ; Mouralová, Kateřina (referee) ; Osička, Karel (advisor)
The aim of this thesis is to describe the replacement of wire cutting laser cutting for cutting inserts made of hard material. Description of current situation in the company Vydona, tender and choice of laser and the need for post-laser workshop. The next section deals with the cutting of a particular sample. The last part of the technical economic assessment are calculated hourly rates of machines and the time and cost loads of different cutting inserts.
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Lifetime measurement of current carriers in silicon solar cells structures
Macháček, Martin ; Hégr, Ondřej (referee) ; Boušek, Jaroslav (advisor)
This thesis deals with a lifetime measurement of current carriers in silicon solar cell structures. In the first chapter there is a description of several recombination models and their participation at a final effective lifetime value. By using these recombination models in a computer simulation it is possible to receive approximate evaluation of some important silicon solar cell structure parameters. The PC1D simulation program was used for this thesis. For the lifetime measurement of real test-wafers two methods were used: QSSPC (quasi-steady-state photoconductance) and MW-PCD (microwave photoconductance decay). There is a detail description of these methods, used measurements machines and differences between both of them in the chapter four. The main objective of the thesis is mentioned in the last chapter, which is mainly focused on a chemical passivation of silicon wafers and deals with a problem of post-passivation wafer cleaning. There are three passivation techniques mentioned: the iodine in ethanol solution, the iodine and polymer in ethanol solution and the quinhydron in methanol solution. In two cases a results, that are adequate to return the tested wafers in the manufacture process, were achieved.
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