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Vlastnosti bipyridin-N,N'-dioxidů v plynné fázi / Properties of bipyridine N,N'-dioxides in the gas phaseDucháčková, Lucie January 2010 (has links)
Lucie Ducháčková Bipyridine N,N'-dioxides are organocatalysts, which are used as a chiral Lewis bases in enantioselective catalysis. The aim of this diploma thesis was systematic investigation of the proton affinities of bipyridine N,N'-dioxide derivatives. Further, the complexation properties and chiral recognition in the gas phase of bipyridine N,N'-dioxide derivatives were examined. Mass spectrometry complemented with infrared multiphoton dissociation spectroscopy and quantum-chemistry calculations using the density functional theory (DFT) were used as the main experimental methods. Bipyridine N,N'-dioxides are a new class of oxygen superbases with proton affinities larger than 1030 kJ/mol. Complexation properties and reactivities of their metal complexes are comparable to 2,2'-bipyridine.
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Využití přenosných Ramanovských spektrometrů pro detekci sulfátů: potenciální aplikace v exobiologii / Use of portable Raman spectrometers for detection of sulfates: potential application in exobiologyKošek, Filip January 2014 (has links)
The detection of mineral phases under in situ conditions has become a primary but sometimes also challenging task in many fields of geoscience. Raman spectroscopy has been used as a powerful tool for the identification of various minerals and organic compounds. The advantages and the relative simplicity made this method a promising choice in the future planetary exploration missions to Mars. The deposits of aqueous minerals including sulfates have been found on the Martian surface. With the development of miniaturized handheld spectrometers there is a need for evaluation of Raman spectroscopy as a method of identification of sulfate phases in their natural conditions. In the first part of this work a handheld spectrometer equipped with 532 nm excitation laser was tested under laboratory conditions during which the ability to distinguish mineral samples representing sulfates of different chemical composition and different degree of hydration was investigated. In the second part, two handheld Raman spectrometers equipped with 532 and 785 nm excitation lasers were used for the characterization of sulfate phases on sites of their natural occurrence located in the Czech Republic. The quality of the Raman spectra acquired under outdoor conditions by both spectrometers was rather average but sufficient to...
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Reakční intermediáty v homogenní zlatné katalýze / Reaction intermediates in homogeneous gold catalysisShcherbachenko, Elena January 2016 (has links)
The presented master thesis is devoted to the investigation of reaction intermediates in homogeneous gold catalysis. Electrospray ionization mass spectrometry (ESI-MS) was used as the primary research technique in this study. Delayed reactant labeling was used as the main method. I have focused mainly on the hydration of 1-phenyl-1-propyne catalyzed by the gold complex [Au(IPr)(MeCN)]BF4 (IPr = 1,3-bis(2,6-di-iso-propylphenyl)imidazol-2- ylidene). I have detected two main intermediates containing one or two gold atoms, respectively (monoaurated and diaurated intermediate). I have obtained rate constants for the degradation of the reaction intermediates and their half-lives. I have derived kinetic isotope effects for the formation and the decomposition of the detected intermediates. I have shown that the kinetics of the degradation of both intermediates is identical, therefore I conclude that hydration of alkynes catalyzed by gold complex [Au(IPr)(MeCN)]BF4 proceeds most probably via neutral monoaurated intermediates. These neutral intermediates are detected by ESI-MS as protonated (monoaurated intermediate) or tagged by a second gold cation (diaurated intermediate). Key words: gold catalysis, reaction intermediates, electrospray ionization, mass spectrometry.
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Ramanova spektrometrie pigmentů sinic, řas a lišejníků v astrobiologickém kontextu / Raman spectrometry of pigments of cyanobacteria, algae and lichens in the astrobiology contextKovács, Michal January 2016 (has links)
This work deals with the possibility of Raman spectroscopical identification of selected biomarkers of extremophile species. It focuses mainly on selected cyanobacteria, algae and lichens with an emphasis on the ability to detect carotenoids. These pigments exhibit three characteristic bands of Raman spectra which represent stretching vibrations C=C; C-C and bending vibration C-CH3 in molecules of carotenoids. Raman spectra were measured not only by laboratory microspectrometers (λ - 514 nm and 532 nm), but also by portable and handheld spectrometers (λ - 532 nm, 785 nm and 700 - 1100 nm). In the case of cyanobacteria, the spectroscopical analysis was performed also on the fractions obtained by high performance liquid chromatography (HPLC). This work critically evaluates the possibilities of Raman spectroscopy to identify the carotenoids of cyanobacteria, algae and lichens. Besides the signal of carotenoids, interpretation of other bands in the Raman spectra corresponding to the presence of other biomarkers is given here for selected samples. The obtained Raman spectra of carotenoids should be interpreted with great caution, because of the ifluence of several factors, which potentially cause unsystematic shifts in the positions of Raman bands (carotenoids bond in biological tissue, interactions with...
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Proteomická charakterizace membránových mikrodomén lidských NK buněk / Proteomic characterization of human NK cell membrane microdomainsKádek, Alan January 2012 (has links)
Proteomic characterization of human NK cell membrane microdomains. (in Czech) Bc. Alan Kádek (Department of Biochemistry, Faculty of Science, Charles University in Prague, Czech Republic) Natural killer (NK) cells are one of the important components of innate immune system. Their main function is to fight against tumors, virally infected or otherwise malformed cells. Plasma membranes of NK cells contain regions with specific lipid composition compared to the surrounding membrane (called membrane microdomains or rafts). Because of their lipid composition, microdomains preferentially accommodate some immunologically relevant proteins and play a role during cellular polarization and signalization. Characteristic feature of membrane microdomains is their partial resistance to solubilization by mild non-ionogenic detergents. In this thesis, microdomains were isolated in a detergent-resistant membrane fraction (DRM) from human NK-92MI cell line and from NK cells immunomagnetically enriched from peripheral blood of non-leukemic donors. For the isolation, Triton X-100 or Brij-98 detergent solubilization and ultracentrifugation in a sucrose density gradient was used. Protein composition of isolated DRMs was analyzed by mass spectrometry employing an LC-MALDI-TOF/TOF method. Protein lists generated in these...
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Hmotnostní spektrometrie v proteomice: strukturní biologie a klinické aplikace / Mass spectrometry in proteomics: structural biology and clinical applicationsPavlásková, Kateřina January 2011 (has links)
Mass spectrometry (MS) is a rapid, specific and very sensitive analytical method with a broad spectrum of proteomic applications such as protein identification and sequencing, 3D protein structure characterization or study of protein-protein interaction. The introduction of two ionization techniques in late 1980's that are able to ionize the large biomolecules such as proteins, oligosaccharides or nucleic acids with no or low fragmentation has started the rapidly expanding field of MS-based proteomics. The presented thesis was aimed at the application of mass spectrometric approaches to answer several proteomic questions. Firstly we have employed the chemical cross-linking in combination with MS analysis to solve the 3D structure and protein-protein interactions of three model systems: (1) homodimeric human regulatory protein 14-3-3, (2) model of 14-3-3 and regulatory domain of tyrosine hydroxylase, and (3) system of two membrane proteins, cytochrome P450 2B4 and cytochrome b5, involved in xenobiotics biotransformation. This approach works in aqueous solutions under physiological conditions and thus preserves native structure of the investigated proteins. The second part of the thesis was focused on MS identification of proteins/peptides in fungal spores of Aspergillus and Pseudallescheria...
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Mechanismus oxidativního spojení naftolů katalyzovaného mědí / Mechanism of copper mediated oxidative coupling of naphtholsSchröpferová, Tereza January 2013 (has links)
The 2,2'-disubstituated 1,1'-binaphthyls (BINOLs) are important ligands in enantioselective synthesis . The major approach for their preparation is based on transition-metal-mediated oxidative C-C coupling of 2-substituted naphtalenes. This diploma thesis examined the mechanism of the coupling reaction in the gas phase using mass spectrometry with electrospray ionization. The aim of this thesis was to compare the selectivity of the copper(II)- catalyzed coupling reaction of 2-naphthol and its derivative with an electron-withdrawing group, to detect possible reaction intermediates, and to determine the origin of the preference of the cross-coupling. The electron-withdrawing group of naphthol slows down the coupling reaction which enabled us to detect the reaction intermediates. The intermediates in the reaction of 2-naphthol were not observed, because the coupling reaction proceeds too quickly. Hence, we have observed only complexes of the coupling products. The preferential cross coupling was explaned on the basis of an interplay between the probability of the formation of binuclear copper complexes and the reactivity of such complexes.
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Analýza přírodních organických barviv a pigmentů pomocí hmotnostní spektrometrie / Analysis of natural organic dyes and pigments by mass spectrometryStýblová, Marie January 2012 (has links)
This thesis named "Analysis of natural organic dyes and pigments by mass spectrometry" investigates the identification of selected natural organic dyes and pigments by qualitative Laser Desorption/Ionisation - Time of Flight Mass Spectrometry analysis (LDI-TOF MS). The advantage of LDI-TOF MS method is its quick and reliable identification of low molecular weight material without preparatory chemical or time-consuming modification of samples. This method can be used for the analysis of works of art or for verifying their authenticity thanks to requiring only a little amount of sample. The LDI-TOF MS was tested on 19 organic dyes and pigments (e.g. alizarin, apigenin, baicalein, flavone, xanthone, tannic acid), four exemplarily prepared lakes (alizarin, purpurin, chrysin a quercetin lakes) and lakes mixed with organic binding media. The method was also successfully applied to two samples of blue color that were taken from Josef Čapek's painting called 'Procházka' (The Walk), that was dating back to 1936.
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Monitorování obsahu Cs-137 spektrometrickým měřením v půdě / Cs-137 content monitoring by spectrometric measurement in soilLEPIČ, Daniel January 2019 (has links)
The aim of the thesis is to compare the results from in situ spectrometry and laboratory determination of the area activity of Cs-137 in samples taken from uncultivated soils. To fulfil the goal, the research question has been determined: Are the results from in situ measurement of the area activity of Cs-137 in uncultivated soil comparable with the results from laboratory measurement of collected soil samples? The theoretical part of the work has been written based on research of book publications, foreign scientific articles and electronic sources, which deal with the issue of radioactivity and its impact on the environment and the principle of semiconductor gamma spectrometry. The practical part of the work deals with the spectrometric measurement using in situ method and the laboratory determination of the area activity of Cs-137 in the soil samples using a semiconductor gamma spectrometer. The measurement and the soil sampling took place in the territory of the Šumava National Park and its adjacent areas in Pilsen Region. There were selected five locations (Nová Hůrka, Prášily, Srní, Nový Brunst and Hadí vrh). By in situ spectrometric measurement the highest values were determined of the area activity of Cs-137 in the location Nová Hůrka (19526 Bq / m2) and the lowest in the location Hadí vrh (5398 Bq / m2). The spectrometric measurements of the soil samples in the laboratory revealed the highest values of the area activity of Cs-137 in the sample from the location Nová Hůrka (10000 Bq / m2) and the lowest values of Cs-137 in the location Hadí vrh (2060 Bq / m2). The contribution of this work is the comparison of in situ spectrometric measurement with the measurement of taken soil samples using the gamma semiconductor spectrometer. The results of this monitoring can provide data on the radiation situation in individual locations in Šumava. By the comparison of the results of the area activity of Cs-137, there has been found a correlation between in situ spectrometric measurements and the laboratory measurements of the soil samples. The results of the area activity of Cs-137 are in an order of magnitude comparable. The differences between the results are probably caused by the measurement conditions.
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Charakterizace lipidů se čtyřmi esterovými vazbami v novorozeneckém mázku pomocí HPLC/MS / Characterization of lipids with four ester bonds in vernix caseosa by HPLC / MSTomášková, Sabina January 2019 (has links)
Diploma thesis is devoted to the analysis of triacylglycerol estolides (TG-est) by HPLC/MS. These lipids contain four ester bonds. TG-est are part of some vegetable oils and in mammals function as a storage form of metabolically important fatty acid estolides. The aim of this thesis was to prove the existence of TG-est in vernix caseosa and explore the possibilities of analysis in this material. Standards of TG-est were studied with using high-resolution and tandem mass spectrometry. Was suggested and optimized HPLC method for TG-est in a reverse nonaqueous system with the use of column Kinetex C18 and gradient elution with acetonitrile and 2-propanol. This method was used for analysis vernix caseosa fraction, and it was shown that TG-est are present in the sample. Attempts to simplify the lipid sample before analysis HPLC/MS by TLC fractionation were not very successful.
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