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Determination of selected metals in fruit compotes
Hauerlandová, Petra ; Vespalcová, Milena (referee) ; Diviš, Pavel (advisor)
This diploma thesis deals with the determination of some metals in fruit compotes packed in cans. There is described the production of fruit compotes and metal packaging legislation relating to the studied issues, the possibility of contamination of food packaging components, packaging corrosion, metal migration from packaging and techniques used for the analysis of metals in the food industry. Concentrations of metals in 14 different fruit compotes from a commercial network in the Czech Republic were determined by ICP-MS technique in the experimental part. Concentrations of metals were detected only in the juice of stewed fruit, because the juice is in direct contact with the surface of packaging, and metals are transferred first into it. The measured values were compared with the maximum permissible levels of metals in fruit compote determined by European legislation. In some cases there were found higher concentrations of tin, but other metals did not exceed the allowable amounts. Concentrations of metals in the compote varied depending on the kind of compote, which could be due to a different chemical composition of compotes depending on the origin of food and process of the fruit production, or a different cans coating material.
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Stents and their applications in medicine
Sokl, Antonín ; Němec, Karel (referee) ; Molliková, Eva (advisor)
The aim of this bachelor thesis, which deals with types of stents and their use in medical area, is the provision od detailed reserches of the most frequently used biomaterials, namely details of metals, ceramics, polymers and composites, considering the suitability of their use for the production of substitutes for particular human body structures. The introductory chapters are devoted to external and internal fixation for fractures, dental implants and replacement of renal function. The following chapters deals with stents and their possible variations, especially the chapters are about esophageal stents, prostatic stents and ureteral stents. The final part of this thesis contains a detailed definition of coronary stents, their functional and shape modifications.
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Removal of lead and other metals from water
Šopíková, Lucie ; Vybíralová, Pavla (referee) ; Biela, Renata (advisor)
This work covers the topic of metals and semimetals in water. It is divided into three parts. First, each element is characterized by its properties and behavior in water. Incidence in the environment, utilization and effects of intake on human body are described for each element. Second, means of elimination from water are introduced. Different chemical, mechanical and biological methods are discussed. In greater detail, precipitate method, cementation, electrochemical processes, sorption and biosorption are reviewed. Third, hands-on filtration experiment of polluted water with the help of different filtration materials is included. This experiment was done in a laboratory belonging to the Institute of Municipal Water Management, Faculty of Civil Engineering, Brno University of Technology.
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Development of Gel Techniques for in situ Measurement of Bioavailable Metals in Soils and Sediments
Kovaříková, Vladěna ; Sommer, Lumír (referee) ; Janoš, Pavel (referee) ; Dočekalová, Hana (advisor)
The doctoral thesis deals with usage of gel techniques for in situ measurement of bioavailable metals in soils and sediments. The DGT technique was applied to soil samples from the localities of Zlín, Tuřany and Chrlice for estimation of bioavailable metals in soils. These soils were amended by sewage sludges in years 1980-1987. The experiment using diffusive gels with different pore size, APA and RG gels, has shown that the DGT can be used for assessment of trace metal soil complexes - small inorganic and larger organic. The results obtained by DGT measurements were approximately up to two orders of magnitude lower than metal concentrations obtained by leaching with sodium nitrate. The leaching with sodium nitrate does not provide true reflection of metal availability to plant root system and soil microorganisms and the DGT technique seems to be a better predictor of metal bioavailability. Only small differences between undisturbed and homogenized soil samples were found out by application of DGT to soil samples from localities of Veverská Bítýška and Ostrovačice. The undisturbed soil is not homogenous and the DGT unit gives information only about the part of the soil which is in direct contact with the unit. The procedure with soil slurry can be recommended for the characterization of large soil areas and estimation of bioavailable metals in soils. Gel techniques were also used for the study of processes occuring in sediments. Mercury species and other metals were analysed in surface water, pore water and sediments collected from two sampling sites in the Dele River in northern France. This river had been polluted during the last century by the activity of Métaleurop factory, which dealt with metal ore treatment. The application of DGT technique using two specific ion-exchange resins, Chelex-100 and Duolite GT-73, provided assessment of mercury in sediment pore water. DGT and DET techniques together with centrifugation provided also high resolution depth profiles of Fe, Mn, Zn, Pb, Cr and Cd in pore water. It is not possible to determine which sampling site was more contaminated. Only small differences in mercury species and metal content were observed between sampling sites. The Dele River can be classified as contaminated river according to total mercury content in sediments and as slightly contaminated river from the point of view of methylmercury content. Correlations between mercury species and sulphide content confirm that total mercury and sulphide content count among factors influencing the mercury release to pore water and controlling processes of methylation and demethylation. Only low toxicity of sediment slurries was found out by the bioluminiscence test with Vibrio fischeri. The results of doctoral thesis demonstrate gel techniques as a very good tool in environmental analysis.
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Removal of selected metals from the water
Pěkný, Mojmír ; Vybíralová, Pavla (referee) ; Biela, Renata (advisor)
In my thesis I focused on the problem of removal of some heavy metals from water. Heavy metals cause deterioration of quality of water sources and bring about a need of complicated water treatment technologies. In particular it is the case of mercury, arsenic, cadmium, lead, chromium and nickel. This diploma thesis focuses on the utilization of adsorption using suitable adsorption materials to reduce concentrations of nickel in drinking water. At the same time it investigates the effectiveness of these materials in the process of removing iron and manganese from water. The first part of my thesis presents an overview of these metals. I write about their occurrence, its forms, properties and significance. The second part of the work focuses on the laboratory observations of the effectiveness in removing iron, manganese and nickel from water. The description of the used sorptive materials is also included.
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Workplace for measuring electrochemical potential of metals
Cápal, David ; Kazda, Tomáš (referee) ; Libich, Jiří (advisor)
This bachelor's thesis describes the issues related to corrosion in electrical engineering. Thesis describes corrosion itself, historical mentions and causes. It also deals in deatail with electrochemical corrosion and the behavior of ions at the electrode-electrolyte interface together with the redox processes that accompany them. This thesis describes the origin and use of these electrochemical reactions as a way of creating electrochemical potential in liquid electrolytes at the metal-electrolyte interface. Thesis also describes measuring methods and evaluation of measured results using polarization curves and Tafel diagrams.
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Study on the Reactivity of Extracellular Polysaccharides Produced by Bacteria
Vacková, Barbora ; Smilek, Jiří (referee) ; Kalina, Michal (advisor)
This bachelor thesis deals with the reactivity of bacterial extracellular polysaccharides. The experimental part deals with extracellular polysaccharide FucoPol. Due to the presence of acyl groups, the polymer has an anionic character and can promote interactions with other positively charged substances. In this bachelor thesis interactions of FucoPol with metals were studied. For measuring, an isothermal titration calorimeter was used, and sorption experiments were performed. The main objective of the work was optimization of conditions for measuring interactions between metals and FucoPol. Connection of metal cations to FucoPol matrix were confirmed by titration calorimetry and sorption experiments. The interaction rate was different depending on the metal which was used. Co2+, Pb2+ a Zn2+ ions showed very weak binding, otherwise Cu2+ a Fe3+ ions had high affinity for the studied biopolymer. FucoPol, as a biodegradable biopolymer, can be in the future one of important industrially produced polysaccharides. It could be used for packaging, biofuel production and production of anti-inflammatory and immune-boosting drugs.
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Complex characterisation of medical herbs and study of their utilization in food industry as a source of functional components
Burdějová, Lenka ; Kráčmar, Stanislav (referee) ; Šilhár, Stanislav (referee) ; Polovka, Martin (advisor)
Presented thesis deals with the complex characterization of extracts from medical plants using spectroscopic and chromatographic techniques, with emphasis on the influence of solvent, post-harvest treatment of the sample, location and year of production on selected parameters. Part of the work is devoted to application of selected extracts from medical plants in suitable form into beverages. The thesis is divided into two parts. At the first part of the work combination of electron paramagnetic resonance, ultraviolet visible spectroscopy, liquid chromatography and inductively coupled plasma optical emission spectrometry was applied for characterization of aqueous, ethanol and dimethylsulfoxide extracts from 10 selected medical plants, which were collected from two different locations during two years (2015, 2016) and post-harvestly treated by two ways (freezing, drying). In total, 39 parameters were determinated: namely total phenolic compounds content, total flavonoids content, 14 specific phenolic compounds, colour characteristics in the CIE L*a*b* system (L *, a*, b *, C*, h°, BI), radical-quenching activity using the cation radical of the 2,2'-azino-bis- (3-ethylbenzothiazoline-6-sulfonic acid), antioxidant/pro-oxidant activity using the spin trapping technique in the presence of 5,5-dimethyl-1-pyrrolin-N-oxide (DMPO)/potassium peroxodisulphate and content of 15 minerals (Al, As, Ca, Cd, Co, Cr, Cu, Fe, K, Mg, Mn, Na, P, Pb, Zn). The results confirmed that the studied parameters of medical plants are influenced by the extraction system, post-harvest treatment of samples, year of production, origin of samples (locality) and species composition. It has been shown that the type of extraction solvent significantly affects the composition of the extracts. On the basis of these analyzes, for food application – the isolation of the main functional components (phenolic compounds, flavonoids) –50% ethanol, post harvest treatment by drying and samples of Mentha piperita, Melissa officinalis, Hypericum perforatum and Salvia officinalis were selected. The second part of the thesis was focused on the application of selected extracts of medical plants to beverages (syrups). The above mentioned plants, 25% ethanol instead of 50% ethanol (due to the limitation of the ethanol content in final raw material), were selected for the application. At first, extraction of medical plants was optimized. Suitable ratio of material and solvent (1:10), extraction time (8 h) and herb absorbency (50–62 %) were determined. The prepared extract after filtration was applied to the syrup concentrate in different ratios to produce one-species syrups and further sensorially tested to select the suitable recipe, the best flavour and basis for the production of two-species syrups. The mint syrup was the most tasty and generally the most acceptable one-species syrup, and sage syrup was selected as the basis for two-species syrups. Further, the most appropriate recipes of the two-species syrups were chosen, the most sensorially acceptable one was selected and further tested if it would be appropriate to colour them. Preferentially, it has been found that it is not necessary to colour two-species syrups. On the basis of the sensory analysis, it has been found that peppermint and sage-peppermint syrups were the most tasty and acceptable syrups, which could be, after further testing, produced industrially to enrich the food market.
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Study of utilization of waste material from the food industry for the removal of metals from waste waters
Křikala, Jakub ; Obruča, Stanislav (referee) ; Diviš, Pavel (advisor)
In this bachelor thesis is discussed the potential use of the marc from the wine production for the removal of metals from wastewaters. Marc containing stems, peels and seeds without any prior chemical treatment were homogenized and rinsed with distilled water to remove soluble impurities. IR spectrometry was used for characterization of the major functional groups responsible for the adsorption of metal ions. The experimental part of this work consisted of the assessment of the optional pH value for adsorption of copper and the maximum adsorption capacity of the used material in column and batch method. The results show that the optional pH values for adsorption of copper were in the range pH 3 – 4. Maximum adsorption capacity were calculated form adsorption isotherms by applying the Langmuir model and found to be 0,260 4 mg/g Cu at a column method and 1,246 2 mg/g Cu after 30 minutes the batch adsorption method. Further, it was experimentally demonstrated that the adsorption of copper in addition to the pH depends also on the initial copper concentration in the solution, contact time and other parameters whose optimization would achieve greater adsorption capacity of the referred material. The results indicate that the marc from the wine production have good potential form removing metals from wastewaters by adsorption.
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