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Antidepresiva - výskyt v přírodních vodách, účinky na organismy, možnosti jejich fototransformace v přírodním prostředí
ČERNÁ, Pavlína
The thesis is focused on one group of organic xenobiotic compounds, antidepressants, their presence in natural waters and their effects on aquatic organisms. A survey of increasing consumption of antidepressants in developed countries is presented together with numerous studies proving rising concentrations of these compounds in natural sufrace waters. Several studies dealing with influence of antidepressants on selected aquatic organisms of different trophic levels are demonstrated. Modern techniques, including AOPs (advanced oxidation processes), used for possible better waste waters treatment are discussed.
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Study of thermal and photodegradation of beer and other fermented beverages
Škoda, Jakub ; Gabriel, Petr (advisor) ; Sigler, Karel (referee)
In this thesis the optical changes of beers and model beer solutions during their photodegradation were studied. The optical changes - change of absorbance - were measured on the prototype of apparatus COLORTURB and were correlated with sensory tested intensity of the lightstruck flavour of beer and with riboflavin content in samples. High correlation between the lightstruck flavour intensity, the loss of absorbance at the wavelength of 450 nm and the riboflavin content loss was found. The partial recovery of the absorbance for both beers and model beer solutions was found and was attributed to the riboflavin photoproducts transformation. Powered by TCPDF (www.tcpdf.org)
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Influence of wood structure on wood properties of tropical species
Baar, Jan
The presented thesis is focused on aesthetical and acoustic properties of tropical wood. The discussed tropical species are utilized in Europe mainly for their unusual appearance and colour in joinery and furniture production. The irreplacable acoustic properties like low internal friction predestine specific species for production of musical instruments. The colour of six selected tropical species - jatoba (Hymenea courbaril L.), massaranduba (Manilkara bidentata A. Chev.), muiracatiara (Astronium graveolens Jacq.), angelim amargoso (Vatairea spp.), angelim pedra (Hymenolobium spp.) and angelim vermelho (Dinizia excelsa Ducke) - were analyzed and expressed in CIEL*a*b* colour space. Subsequently the samples were exposed to artificial sunlight and the light-induced discolouration rate and progress was evaluated. The colour change was rapid in zhe first hours of exposure and all species showed a similar trend in lightness (L*) change - initial darkening replaced by gradual fading. The change in chromatic parameters (a* and b*) change was specific for individual species and probably related to the chemical composition of the extractives. The overall discolouration of lighter coloured wood samples is more distinctive. The extractive content of tropical species is usually high and determines wood colour. The wood of African Padauk (Pterocarpus soyauxii Taub) and Jatoba (Hymenaea courbaril L.) was extracted in a mixture of methanol, water and acetone. The total extractives and total phenolic content was measured. Extractive content was related to colour parameters and above all to lightness in both species. The increase in extractive content leads to a lighter and more yellow colouration of Jatoba wood while African Padauk was darker with a higher amount of extractives. In Jatoba, a positive correlation was found between extractive content and the rate of discolouration. The extractives are responsible for intensive discolouration of tropical woods in contrast to light coloured woods from the temperate zone, where the yellowing is primarily caused by lignin photodegradation. The sound velocity was measured by ultrasound and resonance longitudinal method in heartwood of doussie (Afzelia bipindensis), merbau (Intsia bijuga), wengé (Millettia stuhlmannii Taub.), muiracatiara (Astronium graveolens Jacq.) and zebrano (Microberlinia brazzavillensis). The sound velocity was not related to the density in any case. Although anatomical structural characteristics as fiber length or ray ratio positively influenced it. With longer fibers and slender rays the sound velocity increased. Other acoustic properties like dynamic young modulus of elasticity, specific modulus of elasticity, internal friction and acoustic conversion efficiency (ACE) were determined and were related to measured anatomical features. The differences in composition of wood tissue of individual species were the main source of departure between the assessed relationships. The wood with longer fibers and lower frequency of rays reached lower values of internal friction. The stiffness of wood characterized by the dynamic modulus of elasticity was correlated with fiber and ray tissue. A higher volume of fibers influenced the stiffness positively, while ray volume had the opposite effect on stiffness. Positive effects of fiber length and ray ratio were found for dynamic modulus of elasticity and for acoustic conversion efficiency as well. Both values increased with longer fibers and higher ray ratio. The sound velocity is the basis of some nondestructive techniques for determination of wood mechanical properties. The comparison of density and three dynamic moduli of elasticity (longitudinal and flexural resonance method and ultrasound method) in prediction of mechanical properties was carried out. The density was evaluated as a poor predictor when the samples are not straight-grained and defect free. The interlocked grain often occurred in tropical species and its presence influences the mechanical properties of wood but not wood density. The dynamic moduli of elasticity showed strong correlation with the static modulus of elasticity. Among nondestructive techniques, the weakest correlation was found for the ultrasound method, which is probably partially explained by different measuring mechanism. The prediction of the modulus of rupture is less accurate when the dynamic modulus of elasticity is compared with the static modulus of elasticity; however, it was still good in comparison with the density model.
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Application of Separation Techniques Connected with Mass Spectrometry for the Analysis of Environmentally Important Compounds
Mácová, Daniela ; Čelechovská, Olga (referee) ; Márová, Ivana (referee) ; Demnerová, Kateřina (referee) ; Čáslavský, Josef (advisor)
The identification of the hydrolysis and photodegradation products of flexible polyurethane foams (PUFs) with addition of biooriginated and biodegradable additive was the first topic of this dissertation work. Separation of polyurethane foam hydrolysis degradation products, designed for ecotoxicological tests, was managed by high-performance liquid chromatography coupled with mass spectrometry (HPLC/MS). The degradations product structure was elucidated by tandem mass spectrometry (MSn). PUF photodegradation products were obtained by exposure of materials by irradiation at 254 nm. Semi-volatile degradation products were isolated from the exposed polyurethane by n-hexane extraction; volatile compounds were collected by solid phase microextraction (SPME). Gas chromatography with mass spectrometry (GC/MS) and complete orthogonal tandem gas chromatography with mass spectrometry (GCxGC/TOF MS) was used for separation and identification of photodegradation products. The influence of the bio-filler on the character of degradation products and the possible effect of PUF degradation products on the environment was discussed at the end of this section. The determination of isoprostanes – markers of oxidative stress in tissues of beadlet anemone (Actinia equina) was the subject of the second topic. F2-isoprostanes were synthesized from the arachidonic acid. With thereby prepared isoprostanes the method of determination by liquid chromatography with tandem mass spectrometry (HPLC/MS/MS) was developed and optimized. The isoprostane isolation process from the Actinia equina tissues was optimized with solid phase extraction (SPE). The resulting methodology was used to quantify isoprostanes in tissues of anemones, which were exposed to both moderate and high temperature changes. The temperature changes were used to initiate the oxidative stress in organisms. In addition, concentration levels of unknown compounds were also monitored. These unknown compounds were extracted from tissues together with F2-isoprostanes and their identity is discussed in this dissertation work too. The possibility of using isoprostane levels in the Anthozoa tissues for the oxidative stress monitoring is discussed in the conclusion of this work.
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Analysis of degradation mechanisms oligobutadienes
Baťa, David ; Rozsívalová, Zdenka (referee) ; Frk, Martin (advisor)
This work deals with the studies of liquid oligobutadiens properties in AC electric field by dielectric relaxation spectroscopy method. The current issue in the diagnosis of oligomeric and polymeric materials during the activity of various degradation factors and options of their alleviation and suppression was studied. The existing apparatus is modified for monitoring possibilities of polymeric materials during the action of various degradation and operational factors. Effect of climatic factors are experimentally investigated, especially UV radiation and temperature on the course of the frequency dependence of complex permittivity components with respect to the different composition and length of the polymer chain.
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Farmaka a další chemikálie pro osobní potřebu člověka - jejich stabilita a osud ve vodním prostředí
GOLOVKO, Oksana
The main objective of this study was to assess the influence of sample storage on analysis, the seasonal changes in concentrations and removal efficiencies (REs) in a wastewater treatment plant (WWTP), and the photostability of pharmaceuticals under different sources of light were studied. Data obtained from stability studies showed that storage conditions had a significant impact on the stability of samples, and thus were very important for reliable determination of target compounds. The season can have an important influence on the variability of concentration and elimination of pharmaceuticals and personal care products (PPCPs) in WWTPs throughout the year. The target analytes were 10 antibiotics, 4 antidepressants, 3 psychotropics, 2 antihistamines, 2 lipid regulators, 4 UV filters, 3 analgesics/anti-inflammatories, and 9 anti-hypertensive/cardiovascular drugs. Wastewater samples (136 influents and 136 effluents) were collected from March 2011 to February 2012 and analyzed using two-dimensional liquid chromatography coupled with tandem mass spectrometry. The concentration of most pharmaceuticals was higher in winter. In most cases, elimination of PPCPs was insufficient, and removal rates varied strongly from 38% to 100%. There were significant seasonal trends in the observed REs, which decreased in winter. Photodegradation of 88 pharmaceuticals was investigated in buffered purified water. These experiments were performed both in sunlight and in the laboratory under artificial UV light. We found that photostability of PPCPs depends on the light sources, and that the rate of photolysis was slower under artificial UV light in most pharmaceuticals.
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