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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
51

Studie inkluzních komplexů pesticidů s kukurbiturily / Study of inclusion complexes of pesticides with cucurbiturils

Smitka, Jaroslav January 2013 (has links)
In this work we report the formation of inclusion complexes of the pesticides 1-naphthylacetic acid, 1-naphthylacetamide, napropamide and carbaryl with cucurbit[n]uril (n=7 and 8) and -cyclodextrin hosts. We also report results of the photochemistry of these compounds when free in aqueous solution and included within these nano-containers. The formation of inclusion complexes was studied by electrospray ionization mass spectrometry (ESI-MS) which gave us information about stoichiometry of the complexes and about their reactivity in the gas phase. The photodecomposition and formation of products was followed by high performance liquid chromatography coupled to both mass spectrometry (HPLC-MS) and UV/VIS detector, and spectrophotometry. The studied CBs and their host-guest complexes were readily detected in the gas phase by ESI-MS, mainly as single and double charged ions containing either H+ , Na+ or K+ . The assignments were made based on the m/z values of the observed signals and further confirmed by fragmentation (tandem mass spectrometry - MSn ). All pesticides formed 1:1 (host:guest) complexes. Carbaryl, napropamide and 1-naphthylacetamide also formed 1:2 (host:guest) complexes. Under some solution chemistry conditions, namely for concentrations of cucurbiturils above 50 µM and at low acid and...
52

Biosyntéza samčích feromonů čmeláků a její hormonální regulace. / Biosynthesis of the bumblebee male pheromones and its hormonal regulation.

Bártová, Adéla January 2019 (has links)
Bumblebees are important pollinators, commercially used in large-scale plant growing in greenhouses. Their males produce marking pheromones for mating, which attract young bumblebee queens. These pheromones are often a complicated mixture of chemicals, which is produced in the male labial gland, and the mixture itself is specific for each bumblebee species. The regulation of bumblebee sexual pheromone biosynthesis is largely unknown, and this Master's thesis is focused on the analysis of the mechanisms which lead to the regulation of the Bombus terrestris male pheromone's fat-acid and terpenes biosynthesis, specifically on stereospecific enzymatic reduction of double bond of farnesol. This thesis studies the influence of potential neurohormones on a specific enzymatic mixture, which is involved in the pheromone biosynthesis. Methods used in this project include biochemical, analytic and molecular-biology methods.
53

Využití HPLC a LC-MS/MS metod v diagnostice dědičných metabolických poruch / HPLC and LC-MS/MS methods for diagnosis of inherited metabolic diseases

Bártl, Josef January 2014 (has links)
This dissertation thesis is focused on development and optimization of high- performance liquid chromatography (HPLC) and tandem mass spectrometry (LC-MS/MS) methods, and its utility for diagnosis of inherited metabolic diseases. The first thematic part describes a comprehensive laboratory approach to diagnostics of patients with hereditary xanthinuria by determination of specific markers and enzyme activity. For this purpose HPLC method with diode array detection for measurement of hypoxanthine, xanthine, allopurinol and oxypurinol in urine and plasma and HPLC method with fluorimetric detection for analysis of pterin and isoxanthopterin in plasma were employed. These methods were successfully applied in clinical practice to ascertain two patients with hereditary xanthinuria type I. The second thematic part aims at developing and clinical application of new LC-MS/MS method for simultaneous determination of total homocysteine (tHcy), methionine (Met) and cystathionine (Cysta) in dried blood spots (DBS) and plasma. The results demonstrated the clinical utility of this method for detection of patients with homocystinuria and possibility to distinguish between defects in the remethylation and transsulfuration pathways of homocysteine metabolism. Due to ease of DBS collection and sample transportation...
54

Obsah vybraných fenolických látek v kořeninových rostlinách. / Content of selected phenolic compounds in spice plants.

BERANOVÁ, Zuzana January 2013 (has links)
This work concerns the amount of certain phenols in some of the representatives of families Alliaceae, Lamiaceae and Apiaceae. Phenols in plants are widely represented and highly concentrated. Flavonoids are one of the smallest, yet quite significant classes of phenols. Ingestion of food containing flavonoids can prevent certain diseases such as Arteriosclerosis. cardiovascular and tumor diseases. This work focuses, for their special biological effects, on five flavonoids: Kaempferol, Quercetin, Myricetin, Apigenin and Luteolin. For determining the content of phenols a method of High-performance liquid chromatography (HPLC) was used. Three representative of the family Alliaceae, two representatives of the family Lamiaceae and three representatives of the family Apiaceae were analysed. Only edible parts of the plants were used for the analysis and the amount of phenols was compared in certain plants planted in beddings to the plants planted in greenhouses. At first, the qualitative representantion of phenols was ascertained by the HPLC method. The result is chromatographic profiles, which were then used in calculating the amount of particular phenols. Then the total amounts of kaempferol, quercetin, myricetin, apigenin and luteolin were found out thanks to HPLC method. The biggest amount of total kaempferol was determined in petroselium hortense planted in beddings (588 mg/kg of fresh sample) and in a greenhouse (340 mg/kg of fresh sample). The biggest amount of quercetin was determined in red onion planted in a greenhouse (773 mg/kg of fresh sample) and in ocimum basilicum planted in beddings (535 mg/kg of fresh sample). The biggest amount of apigenin was determined in petroselium hortense planted in a greenhouse (1790 mg/kg of fresh sample) and in petroselium chrispum planted in beddings (3690 mg/kg of fresh sample).
55

Obsah vybraných fenolických látek v léčivých rostlinách / The content of selected fenolic compounds in medicinal plants.

KREJČÍ, Zuzana January 2007 (has links)
The work has been inquired into the problem of content determination of phenolic substances in medicinal plants traditionally used in Czech Republic. Phenolic substances belong to a group of natural compounds, which are purely plant origin. Flavonoids are a part of this extensive group of compounds. As for flavonoids, most attention is paid to quercetin and rutin. It is caused by their easy availability and very significant biological activity. These compounds embody a lot of positive biological effects. They have expressive antioxidant properties, inhibit lipid peroxidation, scavenge free oxygen radicals and bond into the chelates they inactivate some prooxidant metal ions. The latest researches have shown that thanks to their properties natural flavonoids can occurence of chronical diseases, such as arterosklerosis, cardiovascular or tumor disorder. Flavonoids are exploited both in traditional and modern medicine. Same other studies have evidenced that valuable sources of these biologically effective substances are traditionally used medicinal plants. Content of phenolic substances was determined by method of micellar electrokinetic capillary chromatography (MECC) and liquid chromatography (HPLC) in collection of 8 medicinal plants usually used in Czech Republic. For analysis was used freeze-dried and dried plant material. In freeze-dried material was found the highest content of total quercetin in Filipendula ulmaria L. (14200 mg/kg of dry weight) and in Betula pendula Roth. (11800 mg/kg of dry weight). The highest content of rutin contained Sambucus nigra L. (17700 mg/kg of dry weight). Similar values was measured in dried plant material. The content of total quercetin and rutin during drying was unchanged.
56

Obsah vybraných fenolických látek v některých zástupcích rodů Chenopodium L. a Atriplex L. / The content of selected phenolic compounds in representatives of Chenopodium L and Atriplex L genera.

DĚKANOVÁ, Zdeňka January 2010 (has links)
The thesis deals with measuring the content of chosen phenolic substances in some specimen of the genera Chenopodium L. and Atriplex L. Two independent analytical methods were used to determine the content of phenolic substances, namely the Micellar Electrokinetic Capillary Chromatography (MECC) method and the High - Performance Liquid Chromatography (HPLC) method. Two cultured species of the genera Spinacia and Atriplex, three freely growing specimen of the genus Chenopodium and three freely growing species of the genus Atriplex were analysed. The analysis concerned the leaves and the inflorescence of these species.The total content of quercetin and rutin was determined by the MECC method. The highest total content of quercetin was found in the leaves of the Garden Orache (4240 mg/kg of dry matter), the lowest total content of quercetin was found in the inflorescence of the Atriplex prostrata DC. (19.6 mg/kg of dry matter). Rutin was only found in four samples, the rest of the samples contained rutin in quantities below the limit of quantification. The highest content of rutin was found in the leaves of the Lamb´s Quarters (868 mg/kg of dry matter).
57

Tenzidy v povrchových a odpadních vodách / Surfactants in Surface and Waste Water

Štefka, Michal January 2017 (has links)
This work is focused on the occurrence of surface-active substances in the environment. It deals with the development and optimization of methods for the determination of selected surfactants in samples from rivers and from influent and effluent of wastewater treatment plants. Representatives of anionic, nonionic and zwitterionic surfactants were selected as target compounds. Based on optimization of analytical methods and their pilot testing abroad on samples of surface water, the selection of analytes for the conditions in the Czech Republic were corrected and operatively expanded. For the final analysis liquid chromatography with mass spectrometry was used. Analysis of cationic surfactants was realized using liquid chromatograph with UV-VIS detector. This optimized method for analysis of anionic surfactants was applied to real samples. Samples of surface running water were from the River Thurso in Scotland and then from watercourses in the catchment area of Moravia river were collected. In addition to the grab sampling also continuous weekly sampling of water from Tvaroženský potok and Litava was realized. Waste water was collected at inflow and outflow of three wastewater treatment plants (WWTP) in South Moravia (Brno – Modřice, Břeclav and Hodonín).
58

Odstranění vybraných organických polutantů z vody s využitím pokročilých oxidačních procesů / Removal of selected organic pollutants from water using advanced oxidation processes

Dalajková, Nikola January 2018 (has links)
The aim of this diploma thesis is the determination of selected organic pollutants with a focus on artificial sweeteners in waste water from wastewater treatment plant (WWTP) Modřice and the subsequent degradation of the thus obtained concentrations in model water using advanced oxidation processes (AOP). Two sweeteners were determined, namely sucralose and saccharin found in waste water. Synthetic sweeteners are not sufficiently cleaned in the WWTP and penetrate the environment. Effective processes for removing organic substances, including alternative sweeteners, are AOP processes. These processes are based on reactions of highly reactive hydroxyl radical (OH·), which is produced by many chemical reactions. Generally, they use ozone (O3) and hydrogen peroxide (H2O2). On sampling, wastewater samples were treated with Solid Phase Extraction (SPE) and then evaluated by HPLC/MS (High Performance Liquid Chromatography). In observing the degradation of selected sweeteners, three AOP methods were used: O3/UV, H2O2/UV and O3/H2O2. For each of these methods, the efficiency of degradation of sucralose and saccharin was investigated. From the evaluated data it was found that the most efficient AOP process for removing artificial sweeteners from water is the O3/H2O2 method.
59

Příprava a charakterizace extraktu z bezových květů / Preparation and characterization of extract from elderberry flowers

Lukšová, Leona January 2019 (has links)
This diploma thesis deals with the determination of conditions for the preparation of elderberry extract so that the prepared extract retains as many biologically active substances as possible and the way of preserving this extract. Furthermore, the work deals with the transmittance of already specific phenolic acids, namely chlorogenic acid, coffee and ferulic skin, through the Franc diffusion cells. In the theoretical part of the thesis there is a taxonomic classification, description and use of elderberry. Furthermore, significant active substances, in particular phenolic acids, are mentioned. beneficial effects on the skin. The anatomy of the skin and the problem of the penetration of phenolic acids through the skin are described in detail. Finally, a description of high performance liquid chromatography is provided. The experimental part is devoted to verification of optimal conditions for preparation of extract. The best option is to extract the flowers with water at 100 ° C for 10 minutes in a ratio of 1 part by weight of dry flowers and 10 parts by volume boiling water. The ratio of flowers and stems to the phenolic acid content of the extract was also investigated. In the flower extract and its thickened version, the skin permeability was examined by transdermal absorption. The aim of this experiment was to find out if and how much the above mentioned phenolic acids go through the skin. As skin membrane, pork skin from the auricle was used. All determinations of the above phenolic acids in all samples were carried out by liquid chromatography.
60

Internal Flow of Spill-Return Pressure-Swirl Atomizers / Internal Flow of Spill-Return Pressure-Swirl Atomizers

Malý, Milan January 2021 (has links)
Tlakové vířivé trysky (TVT) jsou používané v mnoha aplikacích, kde je potřebná velká plocha kapek nebo kde povrch musí být nanesen kapalinou, např. spalování, sprejové chlazení nebo nanášení barev. Parametry spreje z TVT jsou úzce spojené s jejich vnitřním prouděním. Obtokové trysky vylepšují koncepci klasických TVT přítomností otvoru, skrz který může kapalina odtékat zpět do nádrže. Díky této koncepci je možné regulovat vstřikovací množství kapaliny změnou průtoku tímto otvorem, zatímco se ve vířivé komůrce udržuje vysoký tlak, který zaručí dobrou kvalitu spreje. Obtokové trysky byly historicky málo prozkoumány a jejich vnitřní proudění nebylo studováno téměř vůbec. V této práci je popsáno vnitřní proudění několika obtokových trysek jak experimentálně, tak numericky. Tato data jsou následně korelována s měřenými vlastnostmi spreje. Výsledky ukazují, že přidání obtokového otvoru silně ovlivní vnitřní proudění i v případech, kdy obtokem neproudí žádná kapalina. V některých případech se vůbec nezformuje vzdušné jádro a tím se destabilizuje výtok z trysky, čímž vznikne nestabilní sprej. Mimoosé obtokové otvory generují a stabilizují vzdušné jádro, což pomáhá formovat kapalinovou stěnu a vysoce kvalitní sprej. Nicméně některé konfigurace změnily charakter rozpadu kapalinové stěny, což se projevilo i na kvalitě spreje. Navíc regulační schopnost a stabilita spreje závisí na vzdálenosti obtokových otvorů od osy vířivé komůrky. Na závěr byla upravena neviskózní teorie, která analyticky popisuje vnitřní proudění v TVT, tak aby byla aplikovatelná i na obtokové trysky. Pomocí tohoto přístupu byla odvozena teoretická predikce výtokového součinitele a velikosti vzdušného jádra v závislosti na obtokovém poměru (SFR). Zároveň byly pro obtokové trysky upraveny empirické korelace původně odvozené pro TVT. Tato práce přináší nový vhled k porozumění vnitřního proudění obtokových trysek a její výsledky najdou uplatnění při jejich návrhu.

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