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Distribution of mitochondrial uncoupling proteins in selected tissues from mice and rat
Alán, Lukáš ; Flachs, Pavel (referee) ; Ježek, Petr (advisor)
Mitochondrial uncoupling proteins (UCPs) belong to the superfamily of mitochondrial anion-carriers. The longest known is UCP1, predominantly expressed in brown adipose tissue, where it takes part in nonshivering thermogenesis. In the late 1990s were discovered other sequence homologs of UCP1 with tissue specific distribution. The Function of these "new" uncoupling proteins is still uncertain. It is assumed that each of the isoforms has a specific function depending on the type of tissue. This thesis showed differences in tissue transcription pattern between rat and mice using RT-PCR absolute quantification. Significant differences in pattern were found in lungs, brain and muscle. In each case UCP expression was higher in mice tissues. Mice lungs express mainly UCP2. The difference in mice brain is caused by ucp4 and ucp5 genes transcription and finally in muscle is highest content of UCP3 mRNA. We investigated whether any of ucp transcript can complement ucp2 transcripton in spleen or lungs of ucp2 -/- mice. We did not find any difference which can explain, that in isolated lung mitochondria of fasted ucp2-/- mice were uncoupled in state 4. In the last project, we found relationship between ucp2 transcription in insulinoma INS-1E cells and oxygen levels of the cultivation atmosphere.
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Experimental study of the starved lubrication
Novotný, Antonín ; Čermák, Jan (referee) ; Košťál, David (advisor)
This master’s thesis deals with the experimental study of an elastohydrodynamic contact under conditions of insufficient lubricant supply. Starvation level of this type of the contact may be experimentally determined based on the input position of the meniscus, but this way can’t determine all its levels of starvation. Consequent development in the field of tribology achieved theoretical model that can determine at all levels of starvation depending on the thickness of the lubricant film entering the contact, but it is relatively difficult for experimental verification. The main goal of this work is an experimental study and describes the behavior of elastohydrodynamic contact at an exactly defined thickness of the lubricant film at the contact input. The benefit of this work is a validation of that mentioned theoretical model for base oils and greases made from them, and mutual comparison of their behavior.
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Experimental Study of the Lubricant Film under Starved Conditions
Košťál, David ; Čermák, Jan (referee) ; Dzimko, Marián (referee) ; Ali, Fadi (referee) ; Křupka, Ivan (advisor)
The dissertation thesis deals with an experimental study of an elastohydrodynamic contact under insufficient lubricant supply. Theoretical studies published in this research area focus mainly on the development of theoretical models and there is an insufficient number of experimental studies which validate these models. There are two basic methods of starvation severity control in published theoretical models: by positioning of an inlet meniscus and by setting the thickness of an oil layer in the vicinity of contact inlet. The second method is more suitable when considering a wide range of operating conditions, however it is difficult to ensure experimentally. This thesis presents original experimental results and aims to describe the starvation severity level as a function of the inlet film thickness. Deeper understanding of fundamental processes in starved elastohydrodynamic contacts enables the development of more precise models, better ability of prediction of the starvation and improves the ability to avoid starvation in the early design process of key tribological components.
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Study of starvation in a grease-lubricated elastohydrodynamic contact
Kuňák, Jiří ; Hartl, Martin (referee) ; Svoboda, Petr (advisor)
This diploma thesis is an experimental study of grease lubrication in a starved elastohydrodynamic lubricated (EHL) contact. Lubricating film thickness is measured with tribological experimental device ball-on-disc using optical interferometry and high speed camera. The experiment is aimed at a comparison of results acquired by ball-on-disc device and full scale axial bearing. In addition, this paper also investigates the influence of number of the rolling elements (overrolling time) on the resulting film thickness.
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Study of lubrication films formation under starved lubrication conditions
Košťál, David ; Hartl, Martin (referee) ; Křupka, Ivan (advisor)
The purpose of this thesis is to reveal production mechanisms of lubrication films between non-conformal surfaces in situations, when is not possible to designate lubrication regime as fully flooded elastohydrodynamic contact. Under certain conditions of lubrication volume, rolling speeds, temperatures, lubrication properties or loads could lubrication film decrease under values determined by fully flooded formulas. This regime is designated as starvation at it includes risk of increased wear. In this thesis the methodology and the new simulator of starving contact are described. Obtained film thickness results are compared with existing numerical models.
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Effect of surface texturing on starved contact
Jordán, Jakub ; Náhlík, Luboš (referee) ; Křupka, Ivan (advisor)
The diploma thesis deals with the analysis of the effects surface texturing on starved contact. Experimental verification was realized on apparatus simulating contact between a steel ball and glass disc using colorimetric interferometry and high-speed camera. The work deals with lubrication regimes, problems with starved contacts and surface texturing which can reduce effects of starvation on non-conformal surface contacts.
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Impact of long-term storage on fish welfare
PECHER, Petr
The literature review is completely described by the issue of fish welfare and whether fish feel pain. Then there are describes the basic procedures for measuring fish welfare. Among which belongs for example a cortisol and glucose in fish blood capillary. The aim of the study was to evaluate the effect of different stress factors during storage on fish welfare and to changes in production, exterior and length and weight indicators. For the experiment was selected carp (Cyprinus carpio) divided into two groups by weight 2.5 kg to 2.5 kg and above. The results are the values of visceral fat, capillary blood lactate and changes in production, exterior and length-weight indicators during the application and the end of the experiment.
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