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Optical properties of protective emulsions
Valasová, Denisa ; Veselý, Michal (referee) ; Zmeškal, Oldřich (advisor)
This bachelor´s thesis is aimed to the study of optical properties of protective commercially available emulsions. Chosen emulsions should be responsible for sun protection. They also may be used in cosmetic industry. In the beginning of the thesis, there are defined theoretical features of emulsions and their interaction with UV radiation. Methods which are used to describe optical properties could be found in this section too. The optical properties were measured in thin layer films, in order to simulate emulsions applied on the human skin. UV-VIS spectrophotometry was mainly used to study the optical properties. The obtained results could serve, purely hypothetically, like sun protective tests of chosen emulsions.
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Testing of polymeric materials under climatic conditions of Antarctica
Mičkal, Petr ; Sluková, Michaela (referee) ; Krmíček, Lukáš (advisor)
The bachelor's thesis generally deals with polymer materials and evaluates the possibility of testing their resistance to extreme climates of Antarctica. Described herein are various polymer materials, their characteristics, structure, properties and more thorough and detailed descriptions of selected polymers. The next section describes the basic types of degradation these polymers are exposed to, when facing the extreme conditions of the Antarctic climate. The practical part contains evaluations of tests made on the degraded polymer materials that were collected in Antarctica during the southern Antarctic season of 2013-2014 by Ing. Bc. Pavel Kapler, Ph.D, who is a superintendent at the Czech scientific station JG Mendel.
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Organic dye decomposition by AOP´s methods
Olexová, Barbora ; Dzik, Petr (referee) ; Kozáková, Zdenka (advisor)
This diploma thesis is focused on the study of the influence of advanced oxidation processes on degradation of organic dyes. The field of AOP – very effective physically-chemical methods of wastewater treatment – includes application of strong oxidation agents, UV and ionizing radiation and electrical discharges. For this thesis, two of these methods were chosen – the application of oxidation agent (ozone) and UV radiation. Along with electrolysis, which is mentioned rather marginally in this thesis (it is the subject of the previous thesis), these phenomena are products of electrical discharge in water, where they participate in the processes of degradation in a different way. For all measurement series, two direct azo dyes were chosen as model substances – C.I. Direct Blue 106 and C.I. Direct Red 79. The ozonizer, in which either oxygen or synthetic or technical air were loaded as carrier gases, was used for degradation of dyes by ozone. The generated ozone was loaded into the bubbling vessel with dye solution of different initial concentration (10–130 mg.dm-3), which was followed by other bubbling vessel with KI solution for the next analytical determination of the amount of generated ozone. The other parameters changed were the gas flow (1–2 dm3.min-1), ozonizer output (minimal and maximal), type of dye, pH value of the solution (neutral or acid) and additional electrolyte (NaCl, Na2SO4 or any). The reactor for the study of the influence of UV radiation on degradation of dyes was an UV sterilizer into which the equivalent volume of dye solution was added. The possibilities of experimental settings were limited and only the type of dye, an additional electrolyte and pH value of the dye solution were adjusted (as in the case of ozone). Several series of samples were measured with various input conditions which more or less influenced the degradation of investigated dyes in this experiment. It was found that for both used methods the Direct Blue 106 dye was more degradable (with significantly better results for ozone than for UV radiation). The degradation of Direct Red 79 dye proceeded only by ozone treatment, in the case of the application of UV radiation no degradation occurred. By investigation of the influence of initial concentration of dye on its degradation, it was confirmed that with the initial concentration enhancement the final concentration rises as well, whereas in low concentrations (10–50 mg.dm-3) the initial concentration has no effect. The addition of an electrolyte had an accelerating effect on dye degradation in both methods (NaCl and also Na2SO4 showed similar results though the degradation proceeded in different ways). The addition of HCl accelerated the degradation only in the case of UV radiation; during the application of ozone the pH level of the system did not have any influence on the degradation. Oxygen and synthetic air had the strongest effect on ozone degradation (comparable results); in the case of technical air the final dye concentration was higher up to 30 %. The gas flow of 1.5 dm3.min-1 was stated as optimal with the ozonizer output 30 W (maximal). At minimal power the ozonizer produced very low amount of ozone.
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Physiological, structural, and biochemical leaf traits of selected Poaceae species involved in oxidative stress protection and acclimation to different light conditions
Hunt, Lena Macrie ; Albrechtová, Jana (advisor) ; Lux, Alexander (referee) ; Šantrůček, Jiří (referee)
This thesis examines physiological, structural, and biochemical leaf traits in grasses (Poaceae family) and how they contribute to oxidative stress protection. Light is a major factor contributing both to oxidative stress in plants and the induction of protective mechanisms at the leaf level. The agriculturally important species barley (Hordeum vulgare) was used to investigate responses to varying irradiance and atmospheric CO2 levels. Barley was further used as a model organism to study the influence of different spectral qualities on oxidative protective mechanisms, particularly phenolic compound induction. This thesis also examines the protective leaf functional traits of wild grass species (Nardus stricta, Calamagrostis villosa, Molinia caerulea, and Deschampsia cespitosa) in a high-irradiance arctic-alpine tundra grassland. Phenolic compounds are important protective secondary metabolites in plants that protect against oxidative stress from high irradiance. This thesis evaluates phenolic compounds and their contributions to plant stress tolerance and introduces a novel method of quantifying the histochemical detection of phenolics in leaf cross-sections. Key results indicate that light quantity and quality play major influential roles in the accumulation of phenolic compounds. High irradiance...
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Design and construction of an apparatus to simulate material degradation
SLAVÍK, Radek
The bachelor's thesis deals with the design, construction and testing of a device for simulating material degradation (PSDM). In PSDM, UV radiation is generated, to which the samples are exposed. The samples are also exposed to temperature fluctuations in an attempt to approximate natural climatic temperature variations. A 400 W UV black light mercury discharge lamp is used to generate UV radiation, which approximately generates UVA radiation in the wavelength range of 350 nm - 400 nm. In addition, four Repti Planet UVB lamps, each with a power of 26 W, generate UV radiation, approximately generate UVB radiation in the wavelength range of 290 nm - 350 nm. A convection freezer and a refrigerator are used to simulate temperature fluctuations. Furthermore, the temperature fluctuations are applied to the samples in the PSDM and a dryer with adjustable temperature. The device was tested on a pilot set of samples according to a 30-day schedule that approximately respected the weather conditions. After sample exposure, an analysis of the results was performed by comparing the weights and SEM analysis using an electron microscope. In comparing the weights of the samples, an average decrease of 0,14 % in the weights of the samples simulated in PSDM was observed compared to the original weights of the samples. Differences in the structure of the samples were observed in the SEM analysis. The reference sample showed a duller edge structure of the material with minimal surface damage. Furthermore, there was a small amount of morphological formations with blunt edges on the surface. In the sample exposed to PSDM, sharper edge structures of the material and cavities on the surface were observed. Moreover, greater surface degradation of the sample was observed. The results of the analyses suggest that the resistance of PLA material for FDM 3D printing to weather conditions and UVA and UVB radiation may be significantly higher than generally assumed.
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Use of advanced oxidation processes in pool water treatment
Trávníček, Jakub ; Pivoda, Bohuslav (referee) ; Biela, Renata (advisor)
The research part of the thesis is focused on the use of advanced oxidation processes in the treatment of swimming pool waters. In the first part, the common disinfection technologies that are used domestically and abroad for the treatment of swimming pool waters are described. In the second part, the research focuses on the basic types of advanced oxidation processes used in swimming pool facilities and other similar laboratory-scale technologies with potential for future use in the spa industry. The practical focus of the thesis consists of two parts. In the first part, data from a questionnaire of selected swimming pool facilities in the Czech Republic are processed, which summarizes what technologies are used in the treatment of swimming pool waters in the Czech Republic. The second part consists of a case study that analyses the effect on the quality of treated water before and after the installation of advanced oxidation processes system in the pool recirculation circuit.
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Effect of UV radiation on the change of mechanical parameters of human skin
Mazouchová, Denisa ; Kuchařová, Monika (advisor) ; Klemera, Petr (referee)
Charles University in Prague Faculty of Pharmacy in Hradec Králové Department of Biophysics and Physical Chemistry Candidate: Denisa Mazouchová Supervizor: Mgr. Monika Kuchařová, Ph.D. Title of diploma thesis: Effect of ultraviolet radiation on the change the mechanical parameters of human skin This diploma thesis deals in theoretical part with the properties of human skin, the characteristics of the UV radiation and its effects on human skin. The practical part of the thesis focuses on the in vivo measurement of mechanical parameters of human skin after UV radiation. Mechanical characteristics of human skin were measured in 12 subjects before the application of UV radiation, immediately after application of UV and after 24 hours of rest skin. The experiment used a UV lamp with a wavelength of 370 nm emitted light. The monitored parameters were Hooke's and Newton's coefficients. Hooke's coefficient gives us the stiffness of the skin as a whole , Newton coefficient characterises its viscosity. For measurement of those parameters was used dynamic viscoelastomer. The experiment has been found out that no signifiant ganges of Hooke's and Newton's coefficients were not found immediately after the application of UV radiation of wavelength 370 nm, in 12 volunteers. Significant change occurred only in the...
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Defence mechanisms of phytoplankton exposed to UV radiation
Dvořáková, Jana ; Němcová, Yvonne (advisor) ; Pichrtová, Martina (referee)
Phytoplankton builds an important part of energy flow in the Earth's ecosystem. It forms the basis of the food chain and represents main primary producers. The question arises, due to the continuing ozone depletion, what impact may cause the increasing intensity of UV radiation on aquatic ecosystems. Especially UV-B radiation is capable of penetrating depp into the water column and affects the key physiological processes (e.g. growth, reproduction) and causes acute physiological stress to aquatic organisms including phytoplankton. The gole of my thesis is to summarize the studies focused on the impact of UV radiation on planktonic algae and the defense mechanisms that reduce the negative effects of UV radiation. These mechanisms may be devided into three groups: active avoidance, production of UV-absorbing substances and repairs of damage induced by UV radiation. Powered by TCPDF (www.tcpdf.org)
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Mechanisms of DNA repair in the moss Physcomitrella patens
Holá, Marcela ; Angelis, Karel (advisor) ; Bříza, Jindřich (referee) ; Fajkus, Jiří (referee)
Over the course of an organism's life, its genome is exposed to endogenous and exogenous chemical, physical and biological agents - genotoxins. These genotoxins alter its basic structural components - sugar residues, phosphodiester bonds, and nitrogenous bases. Organisms have therefore evolved a plethora of different strategies to both repair DNA lesions and maintain genomic stability. These DNA repair pathways are linked with several other cell pathways, including chromatin remodelling, DNA replication, transcription, cell cycle control, apoptosis - programmed cell death (PCD), thereby providing a coordinated cellular response to DNA damage. Biochemical mechanisms of DNA repair are relatively well understood in yeast and mammals, however, far less so in plants. While these repair mechanisms are evolutionary conserved, significant differences still remain. Therefore, further investigation is required. This thesis summarises the introduction of a novel plant model - the moss, Physcomitrella patens (Physcomitrella). As a haploid gametophyte with unique characteristics of high frequency of homologous recombination (HR), and apical growth of filaments, it is an ideal organism to study DNA repair in plants. Previous research on Physcomitrella regarding mechanisms of DNA lesion repair induced by...
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