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Mechanochemical Preparation of Alumina-Ceria
Jirátová, Květa ; Spojakina, A. ; Tyuliev, G. ; Balabánová, Jana ; Kaluža, Luděk ; Palcheva, R.
Ceria containing catalysts play an essential role in heterogeneous catalytic processes. However, ceria shows poor thermal stability and low specific surface area and therefore, many studies have been done to improve its properties by combination with other oxides. Alumina-ceria is substantial component of the three ways catalysts, due to the ceria ability to function as the buffer of oxygen and to enhance the oxygen storage capacity of the catalysts. Ceria in these catalysts also functions as structural promoting component, increasing alumina stability towards thermal sintering. Promising method of oxides preparation, very interesting and simple but not sufficiently studied yet is a mechanochemical synthesis. Here we report on the synthesis of nano-sized alumina, ceria and ceria-alumina of various compositions by a wet solid phase mechanochemical reaction of hydrous aluminum, and/or cerium nitrate with ammonium bicarbonate after addition of a small amount of water. The aim of this contribution is to study processes being in progress during synthesis of the mixed oxides, interaction between components and their mutual effect on the properties of resulting products. The phase evolution during mechanical milling and the subsequent heat treatment of precursors were studied by X-ray diffraction, DTA/TG, H2-TPR, NH3-TPD, CO2-TPD, N2 adsorption at -195°C, IR, and XPS spectroscopy. Alumina and mixtures of alumina with different quantities of CeO2 (1- 18 wt. %) were synthesized by mechanochemical method from aluminum nitrate, cerium nitrate and ammonia bicarbonate.
Fulltext: content.csg -  PDF
Plný tet: SKMBT_C22015083108560 - PDF
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Estrogen receptor beta (ERβ) in testicular cells and sperm
Dostálová, Pavla ; Žatecká, Eva ; Děd, Lukáš ; Dorosh, Andriy ; Postlerová, Pavla ; Jonáková, Věra ; Dvořáková-Hortová, Kateřina ; Pěknicová, Jana
Estrogen is a steroid hormone that plays an important role during sperm development in the male and female reproductive tract. Estrogen signalling is a complex process that depends on cell milieu and presence of receptors. Thanks to the steroid nature of estrogens, they can pass through the plasmatic membrane and bind to the intracellular estrogen receptors (ERs). Within the cell, there are several pools of ERs. One of them is localized to the cell nucleus and their activation leads to direct or indirect binding to DNA and ultimately to alternation in gene expression (genomic pathway). Other pools of ERs are associated with plasma membrane or are located in cytosol. Activation of membrane associated ERs leads to rapid non-genomic responses. Nowadays, two classical estrogen receptors are known – ERα and ERβ. Since ERβ is a predominant variant in testes, we focused our study on expression of ERβ variants in murine testes and sperm. We detected two variants of ERβ at mRNA level in both, testes and sperm. These variants differ in 54 nucleotids within the ligand binding domain and this variability results in different affinity to estrogen. We analyzed individual testicular cell types (spermatogonia, spermatocytes, spermatids, Sertoli cells) by RT-qPCR. Our results suggest that both ERβ variants are coexpressed in the same cell type and may therefore interact together. This may have consequences in mediating of estrogen signalling. Moreover, ERβ is expressed more in the later stages of spermatogenesis suggesting the role of ERβ in these stages or alternatively in spermatozoa alone. At the protein level, we detected ERβ in nuclear, membrane and cytosolic fraction prepared from testicular tissue suggesting the involvement of both, genomic and non-genomic, pathways of estrogen signaling in testes. In sperm, anti-ERβ antibodies localized ERβ in acrosome region and tail which is in accordance with the known role of estrogen on capacitation, acrosome reaction and motility.
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CD46 and β1integrin interaction in mouse sperm head
Šebková, Nataša ; Frolíková, Michaela ; Dvořáková-Hortová, Kateřina
CD46 protein plays an important role during fertilization and its role is associated with acrosome stability. CD46 is probably involved in signalling pathways triggering the acrosome reaction. Integrins interact with many cytoskeletal proteins such as actin, therefore changes in the actin cytoskeleton before and after AR may lead to changes in the association and localization of CD46 and β1integrin. Our aim was to monitor mutual CD46 and β1integrin interaction detected by the proximity ligation assay. It generates a localized signal in a form of spots revealing the exact position of the recognition event. Proteins interaction was study in freshly released sperm and sperm during the acrosome reaction, during which there is a gradual relocation of these proteins towards the equatorial segment and the whole sperm head. Proteins α and β tubulin were used as a positive control, α tubulin and β1 integrin as a negative control. In situ PLA showed a distinct spotted signal indicating the mutual interaction of CD46 and β1integrin. A positive response was demonstrated not only in freshly released sperm but also in sperm during the acrosome reaction. Freshly released sperm were distinctively labelled in the acrosome region and the neck, similarly to the positive control. Sperm during the acrosome reaction showed the signal across the whole sperm head region. No signal or sporadic nonspecific staining was detected in the case of the negative control. In summary, our results deliver new information that proteins CD46 and β1 integrin interact with each other. These results suppose the theory that β1 integrin can mediate a connection between CD46 and sperm cytoskeleton thereby molecules of signalling pathways leading to activation of the acrosome reaction.
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Dynamics of mouse sperm capacitation and acrosome reaction
Dvořáková-Hortová, Kateřina ; Frolíková, Michaela ; Děd, Lukáš ; Šebková, Nataša
Capacitation followed by the acrosome reaction (AR), is a very complex event of molecular changes, including acrosome matrix rearrangement and actin polymerization, which mammalian sperm must undergo in the female reproductive tract in order to obtain the ability to penetrate and fertilize the egg. CD46 and β1-integrin belong to specific proteins, which are predicted to interact during molecular reorganization of capacitating sperm. The IZUMO1 as the primary fusion protein of the mammalian sperm is also involved in this dynamic network. We investigated the relationship between the Izumo, CD46 and β1 integrin relocation in the sperm head during the capacitation and AR in vitro. We have already successfully monitored by immunofluorescent labelling the dynamics of proteins CD46 and β1-integrin. The changes in the localization of these proteins associated with the AR and their mutual co-localization was observed. The original β1-integrin location in the freshly released epididymal sperm is in the acrosome and it relocates during the AR further through the sperm head compartments into the equatorial segment and over the whole sperm head. Its density over the equatorial segment is decreasing with the extended time of the AR. Also its presence in the perforatorium of the mouse sperm head is very prominent. The pattern for protein CD46 is extremely similar if not identical in both aspects such as compartment localization and time progress during capacitation and AR in vitro. The molecular interaction of CD46 and β1-integrin was investigated using the Proximity Ligation Assay and Super resolution microscopy STED. The data were statistically analysed. The newly obtained results from CD46 and β1-integrin relocation are in correlation with IZUMO1 dynamics and giving a substantial knowledge on the studied protein network rearrangement during capacitation and AR in mouse spermatozoa.
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Vliv teploty vody a intenzity světla na raný vývoj sumečka afrického v komerčním chovu
PROKEŠOVÁ, Markéta
The successful production of quality early fish stages is crucial for artificial rearing fish species. Nevertheless, it is quite a problematic process, because fish as poikilothermic organisms are highly sensitive to various environmental conditions. Moreover, both fish embryos and larvae are more affected by biotic and abiotic factors (such as predation, stocking density, temperature, light, pH, salinity, oxygen saturation, feeding availability, or their interactions) than older juveniles or adults. Most fish processes such as reproduction, metabolism, survival, development and growth can be considerably (positively, negatively or not) influenced by these conditions. Therefore, it is important to understand their impacts on fish stages during embryonic, larval, juvenile, adult, and eventually the senescent period. Then, following the application of new knowledge to the practise, especially species- and age-specific optimal conditions, should result in higher survival, better growth rate, well developed fish without deformities and lower cannibalism. The objectives of the present thesis were to assess the effect of water temperature and light intensity on the early development (embryonic and larval period) of African sharptooth catfish as a perspective fish species for freshwater intensive aquaculture. Due to its great characteristics (for instance fast growth, ability to breathe atmospheric air, rearing at high stocking density) this species can meaningfully contribute to the global aquaculture production which is expected to rise in the coming years. However, there are still some difficulties in the early rearing African sharptooth catfish regarding the cannibalism, feeding, survival and necessity of detailed information about the effects of some abiotic factors and their interactions.
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Interaction of humans and the environment in residential hauses with walls from inorganic masonry
Brada, Lukáš ; Kocourková, Jana (advisor) ; Zemanová, Lucie (referee)
Interaction of humans and the environment, is subject to the occurrence of mold in
residential buildings. Mold development has been the ultimate result of a variety of
phenomena, processes and causes that have penetrated in various stages of preparation,
implementation and operation of buildings. The negative effects which the mold in a residential area buildings exhibit is primarily a reduction in the use of comfort living
space in the form of health risks in the form of allergic reactions and possibly causing
chronic problems. Chronic problems over time can lead to serious illness. A big role in
the occurrence of mold also plays a reduction of aesthetic values of residential spaces
requiring repair and remedy these deficiencies. When removing adverse events leads to
an unnecessary additional environmental burden.
Problems of fungi in ground buildings are very expansive and interdisciplinary
problems, which incorporates structural, termomechanic, chemical and biologic aspects.
In this undergraduate work I concentrated on the origin of fungi in ground buildings
with inorganic materials and I am discribing at least some important sources and aspects
of fungi origin in each phases origin and exploitation building, with usage of specialised
literature. Model compultations and examples of origin fungi are performed.
Autocephalous origin of fungi in residencial buildings is yet fallback situation, which
can be possibly prevented. But due to conditions for origin fugi can begin long ago this
fallback situation. Store of bias each phases living buildings is accentuated on possibly
fugi production in buildings from project up to operation.
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Decision making in SMEs
Celba, Šimon ; Dömeová, Ludmila (advisor) ; Radim, Radim (referee)
The goal of the work is the creation of a system for decision making support in the company BSL, s.r.o.. The system for the decision making is to resolve the problem with decision making in choosing personal computers for the companys partners.
In the thesis a system for decision making for the company BSL is suggested, as well as its functions and the methodology it utilizes are clearly described. The abilities of the systems are introduced through realistic computations during the choice of a personal computer for individual BSL partners. The results are interpreted through a user interface where the individual options of interaction and users system functions are described. The conclusion of the work includes the results of the individual computations along with suggestion of the best personal computer for individual partners.
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Identification and molecular characterization of the putative immunophilins (IMMs) in the oilseed rape pathogens Leptosphaeria maculans, Leptosphaeria biglobosa, and Plasmodiophora brassicae
Sandhu, Khushwant Singh ; Ryšánek, Pavel (advisor) ; Radovan, Radovan (referee)
Oilseed rape is largely infected by several phytopathogens and two most economical important diseases are blackleg caused by fungus species complex Leptosphaeria maculans and L. biglobosa and clubroot caused by protist P. brassicae. The sequenced genomes of these phytopathogens provide opportunity to uncover various aspects related to disease infection, host pathogen interactions, plant disease resistance, and evolution of pathogens. Considering these we focused on one of the most conserved family called immunophilins (IMMs) in these genomes. IMMs are comprised of three structurally unrelated sub-families including cyclophilins (CYPs), FK506-binding proteins (FKBPs), and parvulin-like proteins (PARs). We identified putative members of IMMs in each phytopathogen using bioinformatics approaches. We further characterized the IMMs based on domain architecture, subcellular localization, exon-intron organization, transcriptomic expression patterns, gene ontology terms, conserved motifs presents and evolutionary analyses. IMMs are performing several vital roles in plants, animals and fungi. However, in phytopathogens their roles are not well established except for cyclophilin that implicates in pathogenicity in some phytopathogens. Therefore, we exploited the role of cyclophilin in L. maculans and L. biglobosa using expression profiles and in P. brassicae using Magnaporthe oryzae cyclophilin deletion mutant. Overall, we concluded that the cyclophilin acts as a virulence determinant in our studied phytopathogens. However, delineating the precise role of other IMMs would also be imperative. Taken together, our findings for the first time shed light on the highly conserved IMM family in the oilseed rape pathogens.
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The effect of housing system on egg shell quality and egg internal quality
Vlčková, Jana ; Tůmová, Eva (advisor) ; Skřivanová, Eva (referee)
In the study 3 experiments were carried out. The objective of the first experiment was to evaluate performance of laying hens, quality of air in poultry house, and microbial contamination of the eggshell in laying hens kept under blue, green, red, and yellow light colour in enriched cages. The laying performance characteristics (hen-day egg production, mortality, and egg weight) were not affected by light colour. Similarly, microbial contamination of the air was not significantly different related to the light colour. There were significant interactions in eggshell contamination between cage floor and light colour in Escherichia coli and Enterococcus. The highest number of Escherichia coli was detected in eggs from hens housed in the middle floor given yellow light and the lowest values on the upper floor also under yellow light colour. Similar results were observed in Enterococcus. The results of our study indicate that the light colour has a minor effect on microbial contamination but the significant influence was in the floor position. The highest microbial egg contamination was found on eggs from the middle floor.
In the second experiment, the effect of housing system (conventional cage, litter, aviary) and feed calcium content (3,0 and 3,5%) on laying performance characteristics, technological quality of eggs, microbial contamination of the eggshell and egg content during storage was evaluated. The significant interaction between housing system and feed calcium content was found in egg weight, eggshell strength, eggshell percentage, eggshell weight, Haugh units and albumen index. The housing system affected egg production, feed intake, egg weight and some characteristics of eggshell quality. From characteristics of eggshell quality the feed calcium content affected only eggshell strength and eggshell percentage. The significant interaction between housing system and storage time was found in contamination of eggshell by total number of microorganisms. The housing system affected also contamination of the eggshell where higher number of Escherichia coli and total number of microorganisms were in eggs from litter. Higher penetration of all monitored species of microorganisms on the eggshell membranes was 2nd and 7th day of storage in the group with 3.5% of calcium in the feed mixture in eggs from the litter. This could be associated with lower quality of eggshell in this type of housing.
In the experiment 3, the effect of different housing system (enriched cage, free range) on technological quality of eggs, microbial contamination of the eggshell, egg content and concentration of protein in albumen during storage was observed. The housing system affected all characteristics of eggshell quality with higher values in cage system. Higher number of pores in eggshell was found in free range. The important relationship between housing system and storage time was indicated in Haugh unit, albumen index, pH albumen and yolk index. The values for characteristics quality of albumen and yolk were better in eggs from cages. Their quality during storage decreased faster in alternative housing systems. There was detected interaction between housing system and storage time also in Escherichia coli, Enterococcus and total number of microorganisms. The highest microbial contamination in fresh eggs was found in free range. The number of microorganisms with storage time significantly decreased faster in eggs from cage system. The penetration of Escherichia coli and total number of microorganisms in albumen was lower in eggs from cage compared to free range. The significant effect of housing system was found in concentration of lysozyme in albumen with higher values in egg from free range. It is obvious that a better quality of the eggs is in the cage housing system. The eggs from this type of housing also remain during storage for longer time in better quality compared with alternative housing systems.
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Adhesion of microalgae Chlorella vulgaris to solid surfaces
Širmerová, Marcela ; Vymazal, Jan (advisor) ; Mojmír, Mojmír (referee)
Although adhesion of bacteria and yeast have been extensively studied by a wide range of experimental and theoretical approaches, significantly less attention has been focused on microalgal adhesion to solid materials. Therefore this doctoral thesis is focused on physico-chemical aspects of microalgal adhesion. The results are based on experimental characterization of surface properties of both microalgae and solids by contact angle and zeta potential measurements. These data were subsequently used in modeling the surface interactions (thermodynamic, classical and extended DLVO models) resulting in quantitative prediction of the interaction intensities. Finally, the model predictions are compared with experimental adhesion tests of microalgae onto model solids in order to identify the physico-chemical forces governing the microalgae-solid interaction. The model solids were prepared in order to cover a wide range of properties (hydrophobicity, surface charge). The results revealed that in low ionic strength environment the adhesion was influenced mostly by electrostatic attraction/repulsion between surfaces, while with increasing ionic strength grew the importance of apolar (hydrophobic) interactions. Among tested materials the highest adhesion of Chlorella vulgaris cells was observed to (3-aminopropyl)triethoxysilane modified glass (APTES glass) mimicking the surface properties of stainless steel. The impact of solid surface properties on the degree of colonization by microlagae was statistically more significant than the influence of culture medium composition on cell surface of Chlorella vulgaris.
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