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Lubricants for bicycle chains
Brychta, Ondřej ; Navrátil, Václav (referee) ; Svoboda, Petr (advisor)
This bachelor thesis deals with the lubrication of bicycle chains. The introduction describes the basics of the friction processes, then there is an analysis of the chains used on bicycles, used materials, analysis of forces and wear in the chains. The last part is devoted to the properties of basic types of lubricants, their additives and the possibilities of their use in cycling.
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Rozhovory přes kutikulu
KOUTKOVÁ, Simona
Leaves of the plants communicate with their environment on the interface formed by epidermis with stomata and cuticle. Cuticle layer, composed of cutin and waxes, represents a barrier, which protects a plant from excessive water loss, but not only this. The changes of these boundaries are dependent on the environmental conditions, especially light (PPFD) and ambient CO2 concentration (Ca). This work tries to answer these questions: How is the availability of CO2 inside the leaf (Ci) altered? How is the development of epidermis related to cuticle formation?
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Plant cuticle
Voloshina, Mariia ; Schwarzerová, Kateřina (advisor) ; Synek, Lukáš (referee)
The cuticle is a lipidic structure covering plant aerial organs, providing mechanical rigidity and acting as a protective barrier. It contains the cutin polyester and waxes, which are derived from very-long-chain fatty acids. These compounds are synthesised in two separate pathways. The cuticular biosynthetic machinery is incredibly complex and employs a multitude of enzymes, some of which are functionally redundant, are present in different tissues or catalyse reactions with substrates of various chain lengths. The mechanisms of how these compounds are transported and how the cuticle is assembled rely on ABC transporters, LTP lipid carrier proteins, cutin synthases, and cutinsomes. Knowledge of these highly dynamic processes is very fragmented and the integrated model of cutin synthesis is yet to be elucidated. A tight connection between the cuticle and the cell wall, conventionally seen as two separate entities, has also been implied. The complexity of these mechanisms is also reflected in their transcriptional and post-transcriptional regulation. While SHINE and MIXTA-like transcriptional factors and the WW-domain protein CFL1 regulate the cuticle's synthesis throughout a plant's development, ABA-dependent MYB transcriptional factors are important during abiotic stress. Recent research also...
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Lubricants for bicycle chains
Brychta, Ondřej ; Navrátil, Václav (referee) ; Svoboda, Petr (advisor)
This bachelor thesis deals with the lubrication of bicycle chains. The introduction describes the basics of the friction processes, then there is an analysis of the chains used on bicycles, used materials, analysis of forces and wear in the chains. The last part is devoted to the properties of basic types of lubricants, their additives and the possibilities of their use in cycling.
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Cuticle, its formation and importance in resistance of plants to abiotic stress
Litkeiová, Veronika ; Hála, Michal (advisor) ; Tylová, Edita (referee)
Plants are daily exposed to stress, biotic or abiotic. Both of these types can be divided into several subgroups. This work is focused on plant cuticle, its formation and function in respect to abiotic stress resistance. The main factors, mentioned in this work, are drought, heat, UV radiation, excessive salinity or ozone exposure. The individual chapters focus on the composition, biosynthesis and changes in the build-up construction caused by certain types of stressors. A significant part is also devoted to cutin and cuticular waxes, which play an important role in plant protection and whose structure is also affected by abiotic stress. Phytohormones, especially abscisis acid, which had its application here, are also not omitted. In the final phase of the thesis, cuticular mutants are mentioned in connection with abiotic stress types illustrating the role and the importance of the cuticle layer. Key words: plants, cuticle, osmotic stress, abscisic acid, cutin, waxes
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