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Techniques using beam of charged particles for imaging and material analysis
Lamborová, Leona ; Kičmerová, Dina (referee) ; Čupera, Jan (advisor)
This bachelor´s thesis deals with techniques using beam of charged particles for imaging and material analysis. There are two types of charged particles that are used for this purpose, electrons and ions. This research study is divided into principles of electron optics and principles of ion optics. Further, there is mentioned function, construction and detectors used for imaging and chemical analysis of scanning electron microscopy, transmission electron microscopy and focused ion beam.
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Microscopy: tool for material analysis
Pleskalová, Kateřina ; Řehořek, Lukáš (referee) ; Čupera, Jan (advisor)
This thesis deals with description of the microscopic techniques that are used to analyse materials. The introductory part briefly summarizes the history of microscopy. The first part of the thesis is focused on light microscopy and the confocal microscopy technique is more elaborated here. The second part of the thesis is focused on basic techniques of electron microscopy, which means transmission electron microscopy and scanning electron microscopy. At the end of each chapter, there is summarization of limits and advantages of these techniques. The preparation of metallographic samples is also briefly described for these microscopic techniques.
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Characterization of PHA producing microbial cells by advanced microscopic and cytometric techniques
Dlouhá, Karolína ; Nováčková, Ivana (referee) ; Obruča, Stanislav (advisor)
The aim of this bachelor thesis is to document production of polyhydroxyalkanoates in selected bacterial strains, which were Pseudomonas thermotolerans, Chelatococcus daeguensis, Tepidiphilus thermophilus and Chelatococcus thermostellatus. In the case of the microorganisms Tepidiphilus thermophilus and Pseudomonas thermotolerans, the production of PHA´s has not yet been described, and in the Chelatococcus bacteria, which were analysed in this work, the production has not yet been documented by electron microscopy. In this work, the selected producers were analysed by flow cytometry first, using BODIPY and Nile Red as fluorescence probes. Selected producers, for which was production confirmed, were analysed by other methods, such as fluorescence microscopy, cryo scanning electron microscopy and transmission electron microscopy. In the bacterial culture of Pseudomonas thermotolerans, PHA´s production wasn´t confirmed by the first analysis by flow cytometer. For other microorganisms was production confirmed. Chelatococcus bacteria clearly proved to be better producers. Bacterial cells of Tepidiphilus thermophilus produced smaller granules and in lower amount.
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Detection of biological structures in TEM microscope images
Cikánek, Martin ; Chmelík, Jiří (referee) ; Potočňák, Tomáš (advisor)
The aim of the first part of this thesis is to explain the theoretical basis of transmission electron microscopy and to mention fundamental parts of transmission electron microscopes. The next part of this work is focused on possible methods of image segmentation, the use of neural networks in the detection of objects in an image and the subsequent clustering of results. The theoretical part of the thesis is concluded with an explanation of some already published methods of automatic detection of biological structures in microscopic images and theoretical design of the algorithm, which will be subsequently developed. The process of training neural networks in order to automatically detect biological structures in an image is described at the beginning of the practical part. This is followed by an evaluation of the results achieved by these networks. Subsequently, cluster analysis methods are applied to these results, the products of which are compared with each other and also with the results obtained by already published methods.
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Transmission Electron Microscopy of Al-Mg Aluminium Alloys with Addition of Sc and Zr
Křivská, Barbora ; Šlapáková, Michaela (advisor) ; Málek, Přemysl (referee)
Abstract. The microstructure and its evolution during isochronal annealing of a twin roll cast Al-3.2Mg-0.19Sc-0.14Zr (wt.%) alloy was investigated by light optical microscopy and electron microscopy. Two procedures - equal channel an- gular pressing and annealing at 300 řC for 8 h were applied to enhance mechanical properties of the alloy. The annealing led to the precipitation of a fine dispersion of Al3(Sc,Zr) particles providing an increase of ∼20 HV in the Vickers microhard- ness. Equal channel angular pressing refined significantly the microstructure and raised the microhardness by about 30 HV. Applying of the 300 řC / 8 h both before and after equal channel angular pressing did not induce further strength- ening. However, the precipitation of the Al3(Sc,Zr) phase had a stabilizing effect when the material was exposed to the subsequent isochronal annealing. 1
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Vliv adipokinetického hormonu na působení jedu z vosičky, \kur{Habrobracon hebetor}, ve svalové tkáni octomilky, \kur{Drosophila melanogaster}
PODLAHOVÁ, Šárka
Adipokinetic hormone (AKH) delays or reduces neuromuscular paralysis caused by the venom of the parasitic wasp Habrobracon hebetor, however the associated mechanism is not known yet. This thesis describes in detail the technique of preparation of semithin and ultrathin sections analyzed by a transmission electron microscopy that enabled detailed observation of changes in muscular ultrastructure of the Drosophila melanogaster thorax after the wasp venom and AKH treatments. The results revealed that the wasp venom induced significant changes in the ultrastructure of myofibrils and mitochondria; however, the changes were reduced after co-application with AKH. AKH itself did not affect organization of muscle fibres but elicited vacuolization in mitochondria. Furthermore the wasp venom treatment led to significant prolongation of sarcomeres.
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Using blind image filtering for images from TEM microscopes
Nováková, Kateřina ; Mézl, Martin (referee) ; Potočňák, Tomáš (advisor)
Předložená práce se zabývá problematikou slepé filtrace obrazů z transmisního elektronového mikroskopu. V úvodu práce je uveden popis transmisního elektronového mikroskopu. Navazující část popisuje mechanismy interakce elektronů se zkoumaným vzorkem a z toho vyplývající zobrazovací techniky elektronové mikroskopie. Poslední kapitola teoretické části práce zahrnuje popis vybraných metod slepé filtrace obrazu zejména s využitím dekompozice obrazu na charakteristické složky. Taktéž je zde uveden výčet metod pro zhodnocení úspěšnosti filtrace. V praktické části jsou popsány aplikované metody slepé filtrace obrazů a výsledky filtrování. Jednotlivé metody jsou mezi sebou porovnány. Získané výsledky a využitelnost aplikovaných metod jsou zhodnoceny v diskuzi.
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Comparison of microscopic diagnostic methods
Veselý, Jakub ; Tihlaříková, Eva (referee) ; Čudek, Pavel (advisor)
This thesis deals with the description and comparison of diagnostic methods, transmission electron microscopy, scanning electron microscopy and atomic force microscopy. The introduction is a description of diagnostic methods. The following experimental section dealing with the diagnosis of ferritic chromium steel sample methods of scanning electron microscopy, atomic force microscopy, transmission electron microscopy and the evaluation and interpretation of measured results. The conclusion provides a comparison, the advantages and disadvantages of diagnostic methods.
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AN INTERPLAY BETWEEN HEAT TREATMENT CONDITIONS AND B2 <-> B19 ' TRANSFORMATION IN Ni-Ti SHAPE MEMORY ALLOYS
Kuběnová, Monika ; Zálešák, Jakub ; Čermák, Jiří ; Dlouhý, Antonín
This study investigates the influence of a heat treatment atmosphere on multistage martensitic transformations in a Ti-50.9at% Ni shape memory alloy. Evacuated quartz tubes were filled with hydrogen while the hydrogen partial pressure was carefully controlled in each experiment. The encapsulated specimens were subjected to heat treatments consisting of annealing and aging. After the heat treatment, the path of martensitic transformation was investigated using differential scanning calorimetry (DSC). On cooling, martensite initial temperatures decrease with the increasing partial pressure of hydrogen applied during the heat treatment. Moreover, the formation of martensite phase may not take place for partial pressures that exceed a certain limit. On the other hand, two-and multiple-step B2/R/B19' martensitic transformations are observed in specimens heat treated at lower hydrogen pressures. Results obtained using transmission electron microscopy (TEM) clearly show that the size of Ni4Ti3 precipitates becomes smaller in alloys that were heat treated at higher hydrogen pressures. The results are discussed in terms of a chain of events. It is suggested that diffusion of hydrogen into the specimen during the annealing step first influences the nucleation of the Ni4Ti3 phase. The sizes and distribution of the Ni4Ti3 precipitates than control the characteristics of B2/B19' transformation.
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Comparison of TEM sample preparation methods for immunogold labeling
GRECHHAMER, Christian
The tracking of antigens in biological samples can be achieved by labeling them with gold-gonjugated antibodies (immunogold labeling). This thesis gives an overview of several sample preparation methods for TEM and investigates their effects on the binding efficiency of antibodies to certain antigens. For this reason, protein samples were processed according to four different protocols, cut into ultra-thin sections and labeled with primary and secondary antibodies. The micrographs, taken during observation with a TEM, were analysed quantitatively and the obtained data was statistically evaluated.
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