|
|
Food composition and feeding selectivity of zooplankton
Lis, Jonáš ; Škaloud, Pavel (advisor) ; Čablová, Radka (referee)
Zooplankton are an important link in the food web between phytoplankton and higher tro- phic levels, and understanding their feeding preferences is the key to unraveling the functions and dynamics of aquatic ecosystems. Current knowledge of zooplankton food composition is limited, consisting mainly of laboratory experiments that have revealed different hunting strategies and selection of prey based on size and nutritional value. Recently, publications have emerged that, through the use of DNA metabarcoding, provide a completely new and comprehensive insight into the diversity of zooplankton diet composition, especially copepods, cladocerans and rotifers. These methods reveal that the feeding niches of copepods and cladocerans are distinct and do not overlap. In general, both groups are said to prefer mainly diatoms as their food, when available. The food niches of rotifers are so diverse that no clear trend can be established for the entire phylum. Cyanobacteria appear to be the main source of energy for zooplankton and are proba- bly consumed by metazooplankton largely as secondary prey when consuming ciliates and other heterotrophic prey. Furthermore, differences in feeding niches between species are known and can be partly explained by their vertical distribution, and different levels of feeding...
|
|
|
Synthesis and evaluation of benzoxaborole derivatives as potential antimicrobial compounds
Needle, Adam Anthony ; Kučerová, Marta (advisor) ; Demuth, Jiří (referee)
Charles University, Faculty of Pharmacy in Hradec Králové Department of Pharmaceutical Chemistry and Pharmaceutical Analysis Student: Adam Anthony Needle Supervisor: PharmDr. Marta Kučerová, Ph.D. Consultant: PharmDr. Petr Šlechta Title of diploma thesis: Synthesis and Evaluation of Benzoxaborole Derivatives as Potential Antimicrobial Compounds It has been revealed, that benzoxaborole moiety can exert OBORT (oxaborole tRNA trapping) mechanism leading to protein synthesis cessation in microorganisms. This work focused on the synthesis and primary in vitro evaluation of N-(1-hydroxy-1,3-dihydrobenzo[c][1,2]oxaborol- 6-yl)(hetero)aryl-2-carboxamide series. The compounds were prepared by reaction between activated (hetero)aryl carboxylic acid and 6-amino group of benzoxaborole moiety via amidic bond formation. Ten compounds were successfully prepared and tested in vitro against clinically important strains of bacteria, fungi and mycobacteria. Noticeable activity against several mycobacterial strains was revealed and the human cell cytotoxicity screening showed low toxicity. This outcome could originate in differences between active sites of human and mycobacterial target enzyme. This series of substances showed selective antimycobacterial properties and may streamline the search for novel...
|
|
|
MW Converter for SW Receiver
Lejsková, Alena ; Lukeš, Zbyněk (referee) ; Šebesta, Jiří (advisor)
This thesis concerns about the network synthesis of receivers with the demand for conversion of the input signal and a following implementation of assigned converter. At first it introduces the readers with the basic division of radio waves and with parts, which are important for a high-quality receiver, then it deals with general properties of input networks of receivers, division of parts and kinds of connection, that are used in the communications. The concept of connection is intended to nonspecialists too, that is why it describes step by step each of parts of the network, including the calculation or possible solution and the choice of convenient parts. The aim is also to present the frequency conversion as an important part of signal receiving that we want to use in communication systems.
|
|
|
Line protection against overload and short circuit
Konšel, Ladislav ; Vaněk, Jaromír (referee) ; Valenta, Jiří (advisor)
This work includes a theoretical treatise on the operation of electrical wiring for the overload and short circuit. This is mainly on thermal effects of over current and their influence on the properties of conductors and insulation. Work Includes links to determine the load current, depending on the properties of leadership and its surroundings. It also deals with the protection of conductors against overload and short circuit. The work includes measurements process of warming wires. Practical project of proposal circuit is created using SICHR. The project includes proposals of conductor’s sizes and safety components for both residential building and individual flats.
|
|
| |
|
|
Optimalization of ferulic acid adsorption on different types of adsorbents
Bariyeva, Aizat ; Diviš, Pavel (referee) ; Pořízka, Jaromír (advisor)
This thesis deals with optimalization processes of adsorption of ferulic acid on different types of sorbents. Specifically, was used the activated carbon as a sorbent of heterogeneous character and Amberlyst A-21 and Amberlit XAD-16 as macroporous polymer sorbents. The ferulic acid is fully characterized in the theoretical part and are discussed the problems of adsorption processes. To determination of the phenolic acid were used UV-VIS and HPLC instrumental methods. The main aim of the experimental part is to optimize various parameters of adsorption, including the construction of adsorption isotherms, determination of maximum adsorption capacity of individual sorbents, study of kinetics and mechanisms of adsorption. Determination of the influence of salt was studied to assess the impact of the inorganic salts on the ferulic acid adsorption capacity. Based on these parameters, was carried out determination of an optimal pH value on 3, with an optimal adsorbent load (m/V ratio = 0,009 gml-1) and a contact time of 50 min for all three adsorbents. Equilibrium studies described by adsorption isotherms and the Langmiur model fitted the best, and the maximum adsorption capacities were determined for all three sorbents with 150,4 mgg-1 for activated carbon, 209,1 mgg-1 for Amberlyst A-21 and 82 mgg-1 for Amberlyte XAD-16. In the study of kinetic models was selected pseudo-second model for all three adsorbents, which correlated with the results obtained by the Langmuir isotherm. The decrease in adsorption capacity in the determination of NaCl influence was 4 % for activated carbon, for macroporous polymer sorbents was decreased by 52 % and 55 % for Amberlyst A-21 and Amberlyt XAD-16 respectively. In a selectivity test under optimized conditions, adsorption strength increased in the order of sinapic acid ferulic acid p-coumaric acid for polymeric sorbent XAD-16 and activated carbon. For the A-21 sorbent the adsorption strength increased in the order of p-coumaric acid ferulic acid sinapic acid. The results of the work indicate the suitability of all three sorbents for the phenolic acid adsorption.
|
|
|
MV Overhead Line Protections and their Coordination with Autoreclosers
Šoustal, Petr ; Skala, Petr (referee) ; Orságová, Jaroslava (advisor)
The aim of this Master’s Thesis is to describe protections for overhead lines in distribution networks. Here are described requirements for the protection and the basic protections. Protections are divided according to their protective function. For each protection is given its use and its power plans. It is stated in the work setting of protection in the real network. On this network is simulated place with short-circuit and described the action of protection. The work also deals with the coordination of protection with automatic circuit breakers. This chapter shows that, given the selectivity is not possible to deploy two or more reclosers (remotely-operated switches) to the core network management. The next chapter describes two representatives reclosers available on the Czech market OSM 27 and GVR 27. Chapter describes and compares their performance characteristics. Conclusion the work includes a proposal protected the lead in incorporating automatic circuit breakers (remotely operated circuit breakers and reclosers). The proposal is based on two different levels of annual number of interruptions and duration of annual general interruption of electricity supply. For these levels the company EGÚ Brno, a.s. proposed several variants of the use of remote-controlled in terms of reducing the cost of the penalty. Our task was to choose a variant that would be applicable in the real network. Reducing costs is feasible only in the limits Ln = 6 failures / year and Lt = 720 min / year, where the selected option No. 4. The limits Ln = 8 failures / year and Lt = 1,080 min / year, not in the real network may no option in terms of selectivity.
|
|
|
Spectral properties of basilar membrane in the cochlea of the inner ear
Jozíf, Lukáš ; Dušek, Daniel (referee) ; Mišun, Vojtěch (advisor)
This thesis aims to verify the function of the cochlea as a spectrum analyzer based on computational modeling of macro-mechanics of the cochlea using FEM. I aim to identify the spectrum of the basilar membrane, which is dependent on the variability of geometry, material characteristics and the presence of liquid environments. Interactions between liquid and solid phases is described by fluid-structure interaction in the system ANSYS. The model is linear and does not pursue an active policy of metabolic processes. Further the work focuses on the decomposition of the sound and check of two best known hypotheses about the transmission frequency of the sound to the brain.
|
|
|
Plasmonically active nanostructures for optical filtering
Idesová, Beáta ; Liška, Jiří (referee) ; Rovenská, Katarína (advisor)
This bachelor’s thesis deals with optical color filters composed of plasmonically active nanostructures and studies the parameters which influence the performance of such filters. Using electron beam litography and selective reactive ion etching, plasmonic hole-like filters were prepared in alumina film on fused silica substrate. The fabricated arrays of nanostructures, acting as optical filters, varied in shape and size of the nanostructures, distances among the nanostructures and their lateral arrangement within the arrays. The influence of these factors on transmission spectra of plasmonic filters was experimentally analysed using optical spectroscopy. A majority of the observed alternations of the measured transmission spectra was consistent with the research study which is, as well, part of this thesis. The highest color filtering selectivity was observed in arrays with divided square structure shape which also exhibited decent transmittance.
|
|
|
Laboratory device involving the high selectivity filters
Tuhý, Luboš ; Kovář, Jan (referee) ; Petržela, Jiří (advisor)
This project deals with the frequency filters of high selectivity. The area frequency filtering is fairly comprehensive and theoretically demanding discipline. The aim of this work isn’t to describe in detail and to include knowledge of the frequency filters, but only to clarify the aforementioned issues. In particular, we focus practically on filters working on other physical principles, especially on the crystal structure of partition filters and ceramic filters. The circuit simulation programs through classes Spice will be one of the parts of the theoretical analysis. There will be presented various options for implementing these filters, and the test products used in the design. The laboratory exercises dealing with frequency filtering and measuring engineered product will be made and based on the theoretical findings of this work. The laboratory exercises will include the developing of the model protocol.
|
guest ::
