Tobacco-specific nitrosamines (TSNA) are carcinogenic constituents derived from alkaloids in tobacco. Researchers are actively exploring several avenues to reduce TSNA levels in tobacco products like moist snuff tobacco. The focus of the research presented within is the quantitative analysis of TSNA in tobacco, specifically N’-nitrosonornicotine (NNN), 4-(methylnitrosamino)-1(3-pyridyl)-1-butanone (NNK), N’-nitrosoanatabine (NAT), and N’-nitrosoanabasine (NAB). Tobacco alkaloids and nitrosamines in tobacco are currently analyzed by different instrumentation due to orders of magnitude difference in their concentrations, chromatographic separation challenges due to structural similarities, and similar mass fragmentation patterns. An analytical column using silica and 1,2-bis(siloxy)ethane hybrid particles of 1.7 µm size is the foundation of a chromatographic separation of NNN, NNK, NAT, NAB, nicotine, nornicotine, anatabine, and anabasine. This is the first rapid and robust quantitative method for the TSNA and their alkaloid precursors using high pH mobile phase conditions with ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS). The suitability of the method is demonstrated by its application to the analysis of reference tobacco materials for cigarettes and moist snuff. In addition, a novel TSNA analytical method was developed using TSNA-specific molecularly imprinted polymers (MIP) as the selective extraction element from tobacco extract. The affinity mechanisms between MIP and TSNA were found to have extensive cross-reactivity to structurally similar alkaloids present in tobacco extract. TSNA-specific MIP was demonstrated to have stronger retention for the alkaloids than for the TSNA substrate. The MIP-TSNA interaction was optimized to create the first analytical method to quantify underivatized NNN and NNK from tobacco extracts by HPLC-UV.

Mag?ster en ciencias m?dicas menci?n gen?tica

Fatty acid amides are an emerging family of bioactive lipids that consists of N-acylethanolamines, N-acylarylalkylamides, N-acylglycines, N-acyl amino acids, N-monoacylpolyamides, and primary fatty acid amides. Short chain fatty acid amides are products of inactivated biogenic amines such as dopamine, histamine, octopamine, and serotonin, whereas long chain fatty acid amides have been implicated in a number of physiological process such as the perception and inhibition of chronic pain through binding to their specific receptors. The most famous; therefore, the most studied long chain fatty acid amide is anandamide or also known as N-arachidonylethanolamine. The biosynthesis of anandamide is well defined; however, other long-chain fatty acid amides, such as the N-acyldopamines, N-acylserotonins, N-acylglycines, N-acyl amino acids, and primary fatty acid amides have remained elusive to date. Understanding the complete biosynthetic pathway for these cell signaling lipids, may yield new exciting molecular targets for human health and disease. Discovery of the long-chain fatty acid amide biosynthetic enzymes has proven to be challenging due to the low biologic abundance of the respective metabolites found in organisms, the interconnection of the pathways, and expense of using mammalian cells and/or organisms. This led to the transition of studying these metabolites and their respective biosynthetic enzymes in Drosophila melanogaster. D. melanogaster is an ideal system to study fatty acid amide biosynthesis because the respective metabolites have been identified, the cost of maintaining the organism is relatively low, and genetic manipulation (RNAi) is universally available. This dissertation is dedicated to defining enzymes involved in D. melanogaster N-acylarylalkyamide biosynthesis. The biologically relevant long-chain N-acylarylalkylamides are comprised of long-chain N-acyldopamines and N-acylserotonins. Very little is known for how these potent cell signaling lipids are biosynthesized in the cell. One possible route is the N -acylation of the respective biogenic amine by an N-acyltransferase enzyme. An enzyme known to catalyze this chemistry is arylalkylamine N-acetyltransferase (AANAT), which catalyzes the formation of N-acetylarylalkylamides from acetyl CoA and the corresponding arylalkylamide. The N-acetylation of biogenic amines is a critical step in Drosophila melanogaster for the inactivation of amine neurotransmitters, sclerotization of the cuticle, and to serve as the penultimate intermediate in the biosynthesis of melatonin. Two AANAT(L) enzymes has been previously evaluated in D. melanogaster and six other putative AANATL enzymes have identified in the fly genome. One AANAT is expressed as two biologically relevant isoforms, AANAT variant A (AANATA) and AANAT variant B (AANATB), where AANATA differs from AANATB by the truncation of 35 amino acids on the N-terminus. The other AANATL enzyme to be previously studied is AANATL2, which was found to catalyze the formation of N-acetyltryptamine from acetyl CoA and tryptamine. Herein, we expressed six AANAT(L) enzymes (AANATA and AANATB, AANATL2, AANATL3, AANATL7, and AANATL8) and sought to define the acyl-CoA and amine substrates for each enzyme. To accomplish this, we developed an activity based screening assay to define acyl-CoA and amine substrates for AANATL2, AANATL3, AANATL7, and AANATL8. Following this work, we defined the acyl-CoA and amine substrate specificity for AANATA, AANATL2, AANATL3, and AANATL7. We have identified acetyl CoA and arylalkylamines as substrates for AANATA, AANATL2, and AANATL3; whereas AANATL7 acetylates histamine and arylalkylamines. AANATL2 was additionally shown to catalyze the formation of long-chain N-acyldopamines and N-acylserotonins. Following these important set of results, we solved the kinetic mechanism for AANATA, AANATL2, and AANATL7 in which these enzymes were shown to catalyze the formation of N-acylarylalkylamides by an ordered sequential mechanism where the acyl-CoA substrate binds first followed by the corresponding amine substrate. Finally, we evaluated the function of structural amino acids on regulating catalysis, structural features of substrates that effect binding and/or catalysis, and generated data leading to a proposed chemical mechanism by means of pH-activity profiles and site-directed mutagenesis of prospective catalytic residues.

The vast variety of long-chain fatty acid amides identified in biological systems is intriguing. The general structure of a fatty acid amide is R-CO-NH-X, where R is an alkyl group and X is derived from an immense variety of biogenic amines. Although structurally simple, the bioactivities of these molecules as signaling lipids are very diverse and have just recently begun to emerge in the literature. Interest in the long-chain fatty acid amides dramatically increased following the identification and characterization of one specific N-acylethanolamine, N-arachidonoylethanolamine (anandamide), as the endogenous ligand for the cannabinoid receptors in the mammalian brain. Since this discovery, the details of N-acylethanolamine metabolism have been elucidated. However, a lesser extent of progress has been made in the last twenty years to identify and study the non-N-acylethanolamine long-chain fatty acid amides. The focus of this dissertation is the elucidation of the biosynthetic pathways for long-chain fatty acid amides, including N-acylglycines, primary fatty acid amides, N-acylarylalkylamides, and N-acylethanolamines. The details of long-chain fatty acid amide metabolism will lead to the determination of possible therapeutic targets. We identified mammalian glycine N-acyltransferase like 3 as the enzyme that catalyzes the formation of long-chain N-acylglycines in mouse N18TG2 neuoblastoma cells, identified and quantified a panel of long-chain fatty acid amides in Drosophila melanogaster extracts by LC/QTOF-MS, established Drosophila melanogaster as a model system to study long-chain fatty acid amide metabolism, and identified arylalkylamine N-acyltransferase like 2 as the enzyme that catalyzes the formation of long-chain N-acylserotonins and N-acyldopamines in Drosophila melanogaster.

Functional water-soluble polymers find applications in a variety of fields including waste-water treatment, pharmaceuticals, cosmetics, drug delivery, and hygiene. Despite the increased demand for these products, understanding of their synthesis by free-radical aqueous-phase polymerization has lagged behind that of polymers produced in organic solvents. In this doctoral work, the free-radical batch and semibatch aqueous-phase polymerization of N-vinylpyrrolidone (NVP), N-vinylformamide (NVF), N-vinylimidazole (NVI) and quaternized vinylimidazole (QVI), as well as NVP polymerized in n-butanol, has been studied. Kinetic models are developed to describe monomer conversion and polymer molecular weight (MW) behaviour of these systems. The expressions developed from independent pulsed-laser studies for propagation (kp) and termination (kt) rate coefficients, including their variation with monomer concentration and conversion, are shown to provide an excellent description of aqueous-phase NVP polymerization. Polymerization of NVP in butanol and of NVF in water are well-represented by the base NVP model, with differences in polymerization rate and polymer MWs simply accounted for by the differences in kp for the systems, indicating that the kt behaviour must be quite similar. The NVI/QVI study demonstrates the importance of a pH-dependent degradative addition reaction to monomer for NVI, with polymerization behaviour identical to that of QVI for pH 1, an effect captured in the model developed to describe the system. The aqueous-phase copolymerization of NVP and NVF was also studied, and reactivity ratios were determined to be very close to unity. This information was combined with the kp and kt expressions used to describe NVP and NVF homopolymerizations, with no other additional parameters required to model the copolymerization rate, copolymer composition and copolymer MW. This result demonstrates that the improved homopolymerization knowledge of these water-soluble monomers can be easily extended to understand their behaviour in copolymerization. / Thesis (Ph.D, Chemical Engineering) -- Queen's University, 2011-12-21 16:05:14.904

Les Offices, monument emblématique de la Renaissance florentine, restent, malgré leur célébrité, encore curieusement méconnus. Considérés comme l’ancêtre des musées européens, ils sont construits par Giorgio Vasari pour accueillir les magistratures de Cosimo I, puis partiellement transformés en galerie par Francesco I. Si la présence d’ateliers d’artistes y est attestée dès 1586, on sait peu de choses sur leur nature et rien sur leur organisation ou leur raison d’être. Fondée sur le dépouillement systématique des archives florentines, notre thèse se propose de retracer l’histoire des ateliers des Offices sous le règne de Ferdinando 1(1587-1609). L’étude combinée des documents, des plans inédits et des oeuvres conservées nous a permis de reconstituer la structure et le fonctionnement des Offices. Grâce à ces sources, nous avons défini et expliqué l’emplacement des ateliers d’artistes et de savants dans le bâtiment, qui était auparavant inconnu : nous avons ainsi pu déterminer plusieurs pôles d’activités, répartis dans tout le bâtiment. En effet, comme dans la ville, les ateliers sont placés, selon leur discipline, dans des quartiers bien distincts. L’identité de ces artistes et savants, ainsi que leurs conditions de travail, ont été établis à l’aide d’une documentation administrative complexe. Nous avons également examiné leur production: objets d’art, remèdes pharmacologiques et instruments scientifiques se caractérisent tous par leur innovation technique. Cette production est en grande partie employée à servir les intérêts politiques du grand-duc, puisqu’elle est envoyée à travers toute l’Europe comme cadeaux attestant du prestige médicéen. Le succès de cette politique provoque d’ailleurs une certaine émulation auprès des cours européennes. En examinant les cas de Pesaro, de Prague et de Paris, au Louvre, nous montrons que les princes européens cherchent à importer le modèle des Offices, en l’adaptant à leurs propres intérêts. / The Uffizi, emblematic monument of the Florentine Renaissance, are still, in spite of their fame, oddly unknown. Considered as the ancestor of the European museums, they were built by Giorgio Vasari to cater for Cosimo I’s public offices, then were partly transformed into a gallery by Francesco I. Even if the presence of workshops is attested ever since 1586, very few about their nature and nothing about their organisation or their purpose is known. Our thesis, based on a comprehensive assimilation of the Florentine archives, intends to recount the history of the Uffizi workshops during Ferdinando I’s reign (1587-1609). The combined study of the documents, the unpublished maps and of the preserved pieces, has enabled us to piece together again the structure and the functioning of the Uffizi. Thanks to these sources, we have defined and explained the location of the artists’ workshops and of scientists inside the building which was unknown before : so we could determine several functional skill areas shared out through the whole building. Indeed, as in town, die workshops are located, depending on their discipline, in separate districts. The identity of these artists and scientists as well as their working conditions, have been set up thanks to a complicated administrative documentation. We have also looked over their production : art objects, pharmacological medicines and scientific instruments are all characterised by their technical innovation. This production is to a great part used to serve die grand-duke’s politica interests because it is sent throughout all Europe as gifts showing the Medicean prestige. The success of this policy causes moreover some emulation in the European courts. By studying Pesaro’s case, in Prague and Paris, we show that die European princes try to introduce the example of die Uffizi, adapting it in their own interests.

Made available in DSpace on 2014-06-11T19:23:11Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-06-28Bitstream added on 2014-06-13T20:10:45Z : No. of bitstreams: 1 godoi_lm_me_jabo.pdf: 221877 bytes, checksum: d6a13644f869b633dd790316dd00f0f4 (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Para conhecer o potencial de plantas de cobertura no fornecimento de nitrogênio para o milho, em sistema de plantio direto, foi avaliado o N potencialmente mineralizável (N0) do solo por meio de ensaio de incubação aeróbia de longa duração e o N disponível por meio dos extratores químicos KCl a quente, Dakota do Sul modificado e tampão fosfato borato a pH 11,2. Foram utilizadas amostras de solo de experimento a campo, instalado em área de Latossolo Vermelho argiloso e conduzido em delineamento em blocos casualizados, com cinco tratamentos: testemunha com vegetação espontânea, sorgo, milheto, mucuna-preta e feijão-de-porco, e cinco repetições. A coleta de solo nas parcelas foi feita após a dessecação das plantas de cobertura e antes do cultivo de milho, nos anos agrícolas de 2007/2008 e 2008/2009. O solo coletado, representativo da profundidade de 0 a 10 cm, foi utilizado no ensaio de incubação aeróbia, em experimento em vasos, com milho, e para as análises químicas. A eficiência dos extratores foi avaliada por meio de testes de correlação, empregando como variáveis de referência o N0 e o N mineralizado acumulado por 30 semanas, obtidos no ensaio de incubação aeróbia, e a produção de matéria seca e o N acumulado na parte aérea do milho, obtidos no experimento em vasos. As plantas de cobertura não diferem entre si quanto ao potencial de fornecimento de N para o milho. O método do KCl a quente é capaz de predizer a mineralização de N, porém os métodos químicos avaliados para predizer o N disponível não são eficientes / Aiming to determine the potential of cover crops to supply nitrogen for corn in no-tillage system, it was evaluated the soil potentially mineralizable N (N0) by long-term aerobic incubation and available N by chemical extractants (hot KCl, modified South Dakota and pH 11.2 phosphate-borate buffer). Soil samples were collected from a field experiment, installed in an Udox and carried out in a randomized block design with five treatments (control with spontaneous vegetation, Sorghum bicolor, Pennicetum glaucum, Mucuna aterrima and Canavalia ensiformis) and five replications. Plots soil sampling was made after the cover crops desiccation and before growing the corn in the agricultural seasons of 2007/2008 and 2008/2009. Soil samples collected from 0 to10 cm depth were used for long-term aerobic incubation, pots experiment with corn, and for soil chemical analysis. Extractants efficiency was evaluated by correlation tests, using as reference the N0 and the mineralized accumulated N over 30 weeks obtained from long-term aerobic incubation, dry matter production and N accumulated in maize shoots, obtained from pots experiment. Cover crops do not differ in their potential to supply nitrogen for corn. Hot KCl is able to predict the N mineralization but the chemical methods evaluated to predict the available nitrogen are not efficients

<p> Variational calculations for hypernuclei and their corresponding nuclear cores have been performed with phenornenological effective Ʌ -N and N-N interactions. Effects of deformation and Majorana exchange on the Ʌ binding energies have been studied. The influence of density dependence in both the Ʌ-N and N-N force has been investigated . The three-body ɅNN interaction has also been considered qualitatively. All these effects help to reduce the Ʌ binding energies in hypernuclei. </p> <p> In addition to the variational calculations, the rigid alpha model has been used to determine the Ʌ binding energy in (5 Ʌ - He). A comparison of the methods is given. </p> Finally, excited states of some hypernuclei have been calculated using the variational ground state equilibrium size. </p> / Thesis / Doctor of Philosophy (PhD)

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