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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.
161

Diverse lanthanoid and lithium complexes with pendant donor amide ligands

Scott, Natalie M(Natalie Maree),1976- January 2001 (has links)
Abstract not available
162

Room Temperature Molten Liquids Based On Amides : Electrolytes For Rechargeable Batteries, Capacitors And Medium For Nanostructures

Venkata Narayanan, N S 08 1900 (has links)
Room temperature molten liquids are proposed to be good alternates for volatile and harmful organic compounds. They are useful in varied areas of applications ranging from synthesis, catalysis to energy storage molten electrolytes have certain unique characteristics such as low vapour pressure, reasonably high ionic conductivity, high thermal stability and wide electrochemical window. These molten liquids can be classified in to two types depending on the nature of the species present in the liquids. One, those liquids consists only of ions (e.g) conventional imidazolium based ionic liquids and other that consists of ions and solvents (e g) acetamide eutectics. Acetamide and its eutectics from room temperature molten solvents that is unique with interesting physicochemical properties. The solvent properties of molten acetamide are similar to water, with high dielectric consist of 60 at 353 k. its acid – base properties are also similar to water, and it can solublise variety of organic and inorganic compounds as well. in the present studies room temperature molten liquids consisting of acetamide as one of the components have been prepared and used for various applications. Room temperature molten electrolytes consisting of magnesium perchlorate/magnesium triflate as one of the constituents have been used for rechargeable magnesium batteries where as those consisting of zinc perchlorate /zinc triflate have been used for zinc based rechargeable batteries. Full utilization of cathode material (y-mno2) is achieved using amide-based molten liquid as electrolyte in rechargeable zinc based batteries. Ammonium nitrate/ lithium nitrate containing electrolytes have been used for electrochemical super capacitors. They have been used as solvent cum stabilizers for metallic nanochains that can be used as substrate in surface enchanced Raman scattering studies.
163

Nouveaux systèmes réducteurs utilisant des hydrosiloxanes comme substituts des hydrures d'aluminium et de bore : application à la réduction des fonctions amides et nitriles

Laval, Stéphane 30 September 2011 (has links) (PDF)
Ces dernières années, les recherches industrielles et académiques ont connu des bouleversements sans précédents liés à la notion de Développement Durable. Les exigences en matière de santé et d'environnement ont poussé les chimistes à concevoir des produits et procédés chimiques qui permettent de réduire ou d'éliminer les substances dangereuses. Les travaux de recherche décrits dans cette thèse s'inscrivent dans ce contexte et concernent la mise au point de nouveaux systèmes réducteurs utilisant des hydrosiloxanes comme substituts des hydrures d'aluminium et de bore. Dans cet objectif, des systèmes associant le 1,1,3,3-tétraméthyldisiloxane (TMDS) ou le polyméthylhydrosiloxane (PMHS) avec des complexes de titane ou de vanadium ont été développés pour la réduction des fonctions amides et nitriles. La nature de l'association hydrosiloxane - métal et du substrat étudié a joué un rôle important sur la performance et la sélectivité des réactions misent en oeuvre. D'une part, les réductions sélectives d'amides (tertiaires et secondaires) et de nitriles en aldéhydes ont été réalisées respectivement en présence du tétraisopropylate de titane(IV) et du triisopropylate d'oxyde de vanadium(V). D'autre part, les réductions d'amides primaires et de nitriles ont conduit aux amines primaires en présence de tétraisopropylate de titane(IV). Enfin, ces systèmes réducteurs ont été utilisés pour la synthèse d'hétérocycles azotés saturés. La réduction de composés dinitriles donne lieu à une réaction d'alkylation réductrice intramoléculaire qui conduit à la formation de dérivés de la pipéridine, de la pyrrolidine et de l'azétidine en une étape
164

Sistemas de purificação de bioetanol para mini destilarias de mandioca /

Salata, Cristiane da Cunha, 1972- January 2012 (has links)
Orientador: Cláudio Cabello / Banca: Manoel Lima de Menezes / Banca: Waldemar Gastoni Venturini Filho / Banca: Ana Paula Cerino Coutinho / Banca: Jorge Horii / Resumo: Este trabalho teve como objetivo purificar bioetanol originário de amido de mandioca utilizando processos de adsorção e troca iônica, avaliar a influência da temperatura, tempo de contato, concentração de adsorvente, vazão, tempo de residência nos processos de adsorção e troca iônica, analisar como os diferentes parâmetros desses processos afetam importantes características físico-químicas do bioetanol, tais como: condutividade, acidez e teste de Barbet, visando propor inovações nos sistemas de purificação, substituindo os processos clássicos de redestilação que são consumidores de energia. O estudo ainda propõe novas metodologias para aplicação na melhoria da qualidade de etanol produzido em pequenas unidades utilizando a mandioca como matéria-prima. Para a realização deste trabalho foram utilizados: a) etanol adquirido e comercializado no mercado, tais como, etanol neutro, etanol de primeira, etanol de segunda; b) etanol produzido em escala piloto no CERAT/UNESP; e c) etanol preparado em laboratório denominado neste trabalho de solução e etanol fortificado. Para a preparação da solução e do etanol fortificado foram adicionadas ao etanol padrão algumas das substâncias orgânicas provenientes da fermentação do amido de mandioca, todas com alto grau de pureza para observar o desempenho das metodologias propostas. Para a purificação das diferentes amostras e das soluções etanólicas foram empregados: a) processo de adsorção; b) processo de troca iônica; e c) processo combinando adsorção e troca iônica. No processo de purificação por adsorção foram testados, como adsorventes... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The objective of present work was to purify bioethanol from cassava starch using adsorption and ion exchange processes, to evaluate the influence of the temperature, contact time, adsorbent concentration, flow rate, residence time in these adsorption and ion exchange processes, to analyze as the parameters different of those processes affect important physico-chemical properties of the bioethanol such as conductivity, acidity and Barbet, to propose innovations in the purification systems, replacing the classic processes of redistillation that are consumers of energy. The study still propose new methodologies for application in the improvement of the quality of ethanol produced in small units using cassava as raw material. For the accomplishment of this work were used: a) purchased and sold ethanol in the market, such as, neutral ethanol, first ethanol, second ethanol; b) ethanol produced in scale pilot in the CERAT/UNESP; and c) ethanol prepared in the laboratory named as solution and contaminated ethanol. For the preparation of the solutions and of the contaminated ethanol, were added to the standard ethanol some organic substances from the fermentation of the cassava starch, all with a high degree of purity to observe the performance of the proposed methodologies. For the purification of samples different and of ethanolics solutions were employed: a) adsorption process; b) ion exchange process; and c) process combining adsorption and ion exchange. In the purification process by adsorption were tested, as adsorbents, different types of activated charcoal and diatomaceous earth. In the ion exchange... (Complete abstract click electronic access below) / Doutor
165

Estudo fitoquímico das folhas e caules de piper arboreum aublet (piperacae)

Costa, Jacqueline Iris Vasconcelos 31 August 2015 (has links)
Submitted by Maike Costa (maiksebas@gmail.com) on 2017-02-24T14:21:28Z No. of bitstreams: 1 arquivo total.pdf: 7731405 bytes, checksum: 68a495488b791e03507898e6666f5361 (MD5) / Made available in DSpace on 2017-02-24T14:21:28Z (GMT). No. of bitstreams: 1 arquivo total.pdf: 7731405 bytes, checksum: 68a495488b791e03507898e6666f5361 (MD5) Previous issue date: 2015-08-31 / The genus Piper is the largest the family Piperaceae, its species are distributed especially in neotropical region of the globe. The phytochemical research of Piper species originated numerous scientific papers in many parts of the world, which led to the isolation of many bioactive compounds such as kavalactones, lignoids, chromones, flavonoids and chalcones, terpenes, steroids, prenylated benzoic acids, aristolactams, phenylpropanoids and amides. Piper arboreum is an erect shrub with about 4.0 meters high. It is popularly known as “fruto de morcego”, “alecrim-de-Angola”, “pau-de-Angola” or “beto-preto” and used in Brazil, in the form of decoction for the treatment of rheumatism, bronchitis, flu and colds and used against venereal and urinary tract diseases. This work reports the phytochemical study of the leaves and stem of P. arboreum Aublet. Using usual chromatographic methods and spectroscopic techniques of IR, MS, 1H and 13C NMR and comparison with the literature data it was possible to isolate and identify from the leaves and stem of Piper arboreum, a mixture of steroids: β-sitosterol and stigmasterol, four aristolactams: Piperolactam A, Piperolactam B, Piperolactam C and Cefaronone B, three phenylpropanoids: 3,4,5-trimethoxyphenyl-propanoic acid, 3,4-dimethoxyphenyl-propanoic acid and 3,5-dimethoxy-4-hydroxyphenyl-propanoic acid and three amides: Arboreumine, N-(12,14-dimethoxy-13-hydroxydihydrocinamoil)-3-pyridin-2-one and N-[12-(15,16-methylenedioxyphenyl)-8( E),10 (E) -heptadienoil-pyrrolidine. The last two compounds are being reported for the first time in the literature. / O gênero Piper é o maior da família Piperaceae, suas espécies estão distribuídas especialmente na região neotropical do globo terrestre. A investigação fitoquímica de espécies de Piper originou inúmeros trabalhos científicos em várias partes do mundo, o que levou ao isolamento de diversos compostos bioativos tais como cavalactonas, lignoides, cromonas, flavonoides e chalconas, terpenos, esteroides, ácidos benzoicos prenilados, aristolactamas, fenilpropanoides e amidas. Piper arboreum é um arbusto ereto de aproximadamente 4,0 metros de altura. Popularmente é conhecida como fruto de morcego, alecrim-de-Angola, pau-de-Angola ou beto-preto e utilizada no Brasil na forma de decocto para o tratamento de reumatismo, bronquite, gripe e resfriado e empregada contra doenças venéreas e do trato urinário. Este trabalho reporta o estudo fitoquímico das folhas e caule de P. arboreum Aublet. Utilizando-se métodos cromatográficos usuais e técnicas espectroscópicas de IV, EM e RMN de 1H e 13C uni e bidimensionais e a comparação dos dados com a literatura foi possível isolar e identificar das folhas o e do caule de Piper arboreum, uma mistura de esteroides: β-sitosterol e estigmasterol, quatro aristolactamas: Piperolactama A, Piperolactama B, Piperolactama C e Cefaronona B, três fenilpropanoides: Ácido 3,4,5-trimetoxifenil-propanóico, Ácido 3,4,-dimetoxifenil-propanóico e Ácido 3,5-dimetoxi-4-hidroxifenil-propanóico e três amidas: Arboreumina, N-(12,14-dimetoxi-13-hidroxidihidrocinamoil)-3-piridin-2-ona e N-[12-(15,16-metilenedioxifenil)-8(E),10(E)-heptadienoil-pirrolidina. Os dois últimos compostos estão sendo relatados pela primeira vez na literatura.
166

Estudo das propriedades anticÃncer da piplartina / Study of anticancer properties of piplartine

Daniel Pereira Bezerra 27 June 2008 (has links)
Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior / A piplartina à um alcalÃide/amida conhecido encontrado em espÃcies do gÃnero Piper com propriedade citotÃxica interessante. Para avaliar o seu potencial antineoplÃsico, um estudo farmacolÃgico de suas propriedades anticÃncer foi realizado em vÃrios modelos biolÃgicos. A piplartina apresentou potente atividade citotÃxica em todas as linhagens tumorais testadas. Por comparaÃÃo da citotoxicidade de molÃculas com estruturas relacionadas com a piplartina, foi identificado que a presenÃa da carbonila α,β-insaturada do anel amÃdico à essencial para a sua atividade citotÃxica. Em cÃlulas mononucleares de sangue perifÃrico de doadores saudÃveis expostas a piplartina, foi observada apenas fraca atividade citotÃxica. Adicionalmente, a piplartina induziu apoptose em cÃlulas leucÃmicas HL-60, com participaÃÃo da via intrÃnseca, de maneira dependente da concentraÃÃo, como observado pelo padrÃo de morfologia celular, integridade da membrana citoplasmÃtica, alteraÃÃo no potencial transmembrÃnico da mitocÃndria e aumento da fragmentaÃÃo do DNA. Na anÃlise do ciclo celular, foi observado bloqueio na fase G2. A piplartina foi capaz de induzir dano ao DNA em cÃlulas V79, como observado pelo ensaio do cometa alcalino e neutro. Seu mecanismo de aÃÃo genotÃxico parece ser semelhante ao da sua atividade citotÃxica. NÃo foi observada atividade mutagÃnica, com ou sem ativaÃÃo metabÃlica (S9), nas linhagens de Salmonella (modelo procariÃtico) testadas. Por outro lado, a piplartina foi mutagÃnica e recombinogÃnica em linhagens de Saccharomyces cerevisiae (modelo eucariÃtico). Isto pode ser explicado pela diferenÃa fisiolÃgica entre a enzima topoisomerase II de eucariÃticos e procariÃticos, refletindo uma possÃvel interferÃncia da piplartina sobre a atividade desta enzima. No ensaio do micronÃcleo in vivo, a piplartina induziu aumento da freqÃÃncia de micronÃcleo na maior dose testada (100 mg/kg). Entretanto, nÃo alterou a proporÃÃo de eritrÃcitos policromÃticos/normocromÃticos. Em estudo farmacocinÃtico, um mÃtodo bioanalÃtico por LC-MS/MS foi desenvolvido e validado para a quantificaÃÃo da piplartina em plasma de ratos. O mÃtodo apresentou-se linear, sensÃvel, preciso e exato. No estudo de disposiÃÃo cinÃtica, a piplartina apresentou um perfil de absorÃÃo tÃpico de um modelo monocompartimentado. Adicionalmente, os nÃveis plasmÃticos sÃo compativeis com o valor obtido na citotoxicidade in vitro o que nos leva a propor que a atividade anticÃncer da piplartina deve-se as suas propriedades citotÃxica direto. No ensaio de atividade antitumoral, a combinaÃÃo da piplartina com o 5-fluourouracil levou a um aumento da inibiÃÃo do crescimento in vitro e in vivo. AlÃm disso, anÃlises hematolÃgicas mostraram leucopenia apÃs tratamento dos animais com o 5-fluourouracil, o qual foi revertido pela combinaÃÃo com a piplartina. Esses dados sugerem que a piplartina apresenta um potencial anticÃncer promissor / Piplartine is a known alkaloid/amide from Piper species with interesting cytotoxic properties. In order to understand the antineoplasic potential of piplartine, a pharmacological study was performed in several biological models. Piplartine displayed potent cytotoxicity against all cancer cell lines. By comparing the cytotoxicity of selected molecules that differ in structural elements, it was identified that the presence of the α,β-unsaturated carbonyl moiety of the amide ring is an important structural requirement for cytotoxic activity. In healthy peripheral blood mononuclear cells exposed to piplartine, it was observed only weak cytotoxic activity. Moreover, piplartine treatment induced apoptosis in HL-60 cells, by the intrinsic pathway, in a dose-dependent manner, as observed by morphology and cytoplasmatic membrane integrate changes, alteration in mitochondrial membrane potential and an increase in internucleosomal DNA fragmentation. In the cell cycle analysis, piplartine induced G2 cell cycle arrest. Piplartine treatment induced DNA strand breaks in V79 cells, as detected by neutral and alkaline comet assay. Its genotoxic mechanism of action seems to be similar to its cytotoxic activity. No mutagenic effect, with or without metabolic activation (S9 mix), in Salmonella strains (prokaryotic model) was observed under experimental conditions. On the other hand, piplartine was mutagenic and recombinogenic in Saccharomyces cerevisiae assays (eukaryotic model). This can be explained due to the differences in physiological between eukaryote and prokaryote DNA topoisomerase II, reflecting a possible interference of piplartine upon this enzyme activity. In vivo micronucleus test, piplartine increased in the levels of micronuclei in the highest dose tested (100 mg/kg). Nevertheless, no bone marrow cytotoxicity was found after piplartine-treated animals as observed by the polychromatic/normochromatic erythrocyte ratio. In pharmacokinetic study, a LCâMS/MS bioanalytical method for the determination of piplartine in rat plasma was established. The method developed shows great linearity and low quantification limit; precision and accuracy were within the acceptable ranges for bioanalytical purposes. In the concentrationâtime profiles, piplartine showed absorption kinetic of a monocompartimental model. Additionally, the plasma levels are compatible with the in vitro cytotoxicity which leads us to propose that the anticancer activity of piplartine is due to its direct cytotoxic properties. In antitumor assay, the combination of piplartine with 5-fluourouracil led to an in vitro and in vivo increasing of the tumor growth inhibition. In addition, hematological analysis showed leukopenia after 5-fluourouracil treatment, which was reversed by the combined use of piplartine. These data suggest that piplartine has promising anticancer potential
167

Metabólitos secundários das raízes de Piper crassinervium Kunth (Piperaceae) / Secondary compounds from roots of Piper crassinervium Kunth (Piperaceae)

Renata Fogaça da Silva 12 December 2006 (has links)
O extrato bruto (DCM:MeOH 2:1) das raízes de Piper crassinervium foi submetido a fracionamentos cromatográficos resultando no isolamento e identificação de oito substâncias, sendo estas uma flavanona (5,4\'-diidroxi-7-metoxiflavanona [isosakuranetina]), duas hidroquinonas preniladas (1,4-diidroxi-2-[3\',7\'-dimetil-1\'-oxo-2\'-E-6\'-octadienil]-benzeno e 1,4-diidroxi-2-[3\',7\'-dimetil-1\'-oxo-2\'-Z-6\'-octadienil]-benzeno), um cromeno (ácido-2-metil-2-[4\'-metil-3\'-pentenil]2H-1-benzopirano-6-carboxílico), um derivado prenilado do ácido benzóico (ácido 4-hidroxi-3-[3\',7\'-dimetil-1\'-oxo-octa-2\'-E-6\'-dienil]-benzóico), uma amida isobutílica (piperlonguminina) e duas amidas piperidínicas (piperina e diidropiperina). As substâncias isoladas tiveram suas estruturas químicas determinadas por experimentos de espectrometria de massas, RMN de 1H e 13C e comparadas com os dados da literatura. / The crude extracts of the roots of Piper crassinervium was submitted to chromatographic steps yielding eight compounds including a flavanone (5,4\'-dihydroxy-7-methoxyflavanone [isosakuranetin]), two prenylated hydroquinones (1,4-dihydroxy-2-[3\',7\'-dimethyl-1\'-oxo-2\'-E-6\'-octadienyl]-benzene and 1,4-dihydroxy-2-[3\',7\'-dimethyl-1\'-oxo-2\'-Z-6\'-octadienyl]-benzene), one chromene (2-methyl-2-[4\'-methyl-3\'-pentenyl]-2H-1-benzopyran-6-carboxylic acid), one prenylated derivative of benzoic acid (4-hydroxy-3-[3\',7\'-dimethil-1\'-oxo]2\'-E-6\'-octadienyl-benzoic acid), one isobutyl amide (piperlonguminine) and two piperidine amides (piperine and dihydropiperine). The structures of the isolated compounds were determined by mass spectrometry, 1H and 13C NMR data by comparison with the literature data.
168

Preparação de amidas graxas derivadas do óleo de maracujá utilizando diferentes métodos catalíticos

Almeida, Camila Guimarães de January 2014 (has links)
Submitted by Renata Lopes (renatasil82@gmail.com) on 2017-05-09T17:53:03Z No. of bitstreams: 1 camilaguimaraesdealmeida.pdf: 4348908 bytes, checksum: 2103ec3e5867e67082b5aeed5c341eba (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2017-05-17T14:31:51Z (GMT) No. of bitstreams: 1 camilaguimaraesdealmeida.pdf: 4348908 bytes, checksum: 2103ec3e5867e67082b5aeed5c341eba (MD5) / Made available in DSpace on 2017-05-17T14:31:51Z (GMT). No. of bitstreams: 1 camilaguimaraesdealmeida.pdf: 4348908 bytes, checksum: 2103ec3e5867e67082b5aeed5c341eba (MD5) Previous issue date: 2014 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / As N-aciletanolaminas graxas, assim como seus derivados, são encontradas com frequência na natureza. Pertencem a uma classe de compostos não iônicos amplamente utilizados por suas propriedades surfactantes em detergentes e xampus, bem como em formulações cosmético-farmacêuticas. O uso de matéria-prima renovável obtida a partir de resíduos industriais se mostra uma alternativa interessante para a síntese destas moléculas. As sementes de maracujá, subprodutos da indústria alimentícia, são ricas em triacilgliceróis que podem originar amidas graxas através de reações de aminólise direta ou indireta. Neste trabalho são descritas a síntese de misturas contendo amidas graxas obtidas a partir do tratamento do óleo de maracujá com três diferentes aminas na presença de catalisadores químicos heterogêneos e homogêneos, bem como irradiação de micro-ondas. Os catalisadores heterogêneos selecionados, descritos na literatura para reações de transesterificação, mostraram-se eficientes em reações de aminólise direta e indireta. A otimização das condições reacionais (modo de aquecimento, quantidade de catalisador, tempo reacional) mostrou que o óxido misto ZnO.La2CO5.LaOOH (2,3 % m/m) foi o que apresentou as maiores conversões (>99%) em menor tempo reacional (8 h). O ácido p-sulfônico calix[4]areno previamente descrito para reações de esterificação de ácidos graxos, mostrou-se eficaz em reações de transesterificação (96-99% de conversão) e aminólise direta de triglicerídeos (50->99% de conversão). Após caracterização dos óleos e das misturas de amidas graxas através dos métodos espectroscópicos usuais (RMN de 1H, RMN de 13C e IV) suas propriedades biológicas foram avaliadas in vitro. Os óleos vegetais apresentaram atividade antioxidante atribuída à presença de tocoferóis e ao alto índice de insaturação dos triglicerídeos presentes. As misturas também foram avaliadas quanto ao potencial antibacteriano e antifúngico. Apenas a mistura de N’N’-dimetiletilenodiamida graxa apresentou atividade frente a quatro cepas de Candida sp. testadas (CIM = 32-128 µg/mL). A incorporação das misturas de amidas graxas em cremes e sabonetes está em estudo. / Fatty N-aciletanolamines, as well as their derivatives, are frequently found in nature. They belong to a class of nonionic compounds widely used for their surfactant properties in detergents and shampoos, as well as in cosmetic and pharmaceutical formulations. The use of renewable raw materials obtained from industrial wastes appears as an interesting alternative for the synthesis of these molecules. Passion fruit seeds, subproducts of the food industry, are rich in triacylglycerols that can originate fatty amides through reactions of direct or indirect aminolysis. In this work we describe the the synthesis fatty amide mixtures obtained through the treatment of passion fruit oil with three different amines in the presence of heterogeneous chemical catalysts or under microwave irradiation. The selected heterogeneous catalysts, previously reported in the literature for transesterification reactions, proved to be effective in direct and indirect aminolysis. The optimization of the reaction conditions (heating mode, amount of catalyst, reaction time) showed that the mixed oxide ZnO.La2CO5.LaOOH (2.3%, w/w) led to the highest conversions (>99%) in a shorter time (8 h). The calix [4]arene p-sulfonic acid previously described for the esterification of fatty acids, was effective in transesterification reactions (96-99 % conversion) and direct aminolysis of triglycerides (50- >99% conversion). After the characterization of passion fruit oils and of the fatty amides mixtures using the usual spectroscopic methods (1H and 13C NMR, IR) their biological properties were evaluated in vitro. The vegetable oils showed antioxidant activity attributed to the presence of tocopherols and to the high index of unsaturation of the present triglycerides. The mixtures were also evaluated for their antibacterial and antifungal potential. The mixture of fatty N'N'-dimetiletilenodiamide mixture was the only one to display activity against the four strains of Candida sp. tested (MIC = 32-128 µg/ml). The incorporation of fatty amides mixtures in creams and soaps are under study.
169

A regulatory role for N-acylethanolamine metabolism in Arabidopsis thaliana seeds and seedlings.

Teaster, Neal D. 05 1900 (has links)
N-Acylethanolamines (NAEs) are bioactive acylamides that are present in a wide range of organisms. Because NAE levels in seeds decline during imbibition similar to ABA, a physiological role was predicted for these metabolites in Arabidopsis thaliana seed germination and seedling development. There is also a corresponding increase of AtFAAH (fatty acid amide hydrolase), transcript levels and activity, which metabolizes NAE to ethanolamine and free fatty acids. Based on whole genome microarray studies it was determined that a number of up-regulated genes that were responsive to NAE were also ABA responsive. NAE induced gene expression in these ABA responsive genes without elevating endogenous levels of ABA. It was also determined that many of these NAE/ABA responsive genes were associated with an ABA induced secondary growth arrest, including ABI3. ABI3 is a transcription factor that regulates the transition from embryo to seedling growth, the analysis of transcript levels in NAE treated seedlings revealed a dose dependent, inverse relationship between ABI3 transcript levels and growth, high ABI3 transcript levels were associated with growth inhibition. Similar to ABA, NAE negatively regulated seedling growth within a narrow window of early seedling establishment. When seedlings are exposed to NAE or ABA within the window of sensitivity, the induction of genes normally associated with the ungerminated desiccation tolerant state resumed. The NAE tolerant FAAH overexpressor and the NAE sensitive FAAH knockout both had a NAE/ABA sensitive window similar to the wild type A. thaliana. The abi3-1 ABA insensitive mutant does not undergo growth arrest upon exposure to ABA, but NAE did induce growth arrest when treated within the sensitivity window. This evidence showed that although NAE functions within an ABA dependent pathway, it also functions in an ABA independent signaling pathway. The FAAH overexpressor is tolerant to NAE through its ability to quickly metabolize NAE from the growth media, yet it is hypersensitive to ABA. The FAAH overexpressor also displayed hypersensitivity to GA, which improved its delayed germination in non-stratified seed, while the FAAH knock out showed GA insensitivity. Overall, these results showed that NAE functions as a negative regulator of germinating seed and seedling growth in ABA dependent and independent signaling pathways, and that altered NAE metabolism may interfere with ABA/GA perception in germinating seed.
170

Computational Studies of C–H/C–C Manipulation Utilizing Transition Metal Complexes

Pardue, Daniel B. 05 1900 (has links)
Density Functional Theory (DFT) is an effective tool for studying diverse metal systems. Presented herein are studies of a variety of metal systems, which can be applied to accomplish transformations that are currently difficult/impossible to achieve. The specific topics studied utilizing DFT include: 1) C–H bond activation via an Earth-abundant transition metal complex, 2) C–H bond deprotonation via an alkali metal superbase, 3) and amination/aziridination reactions utilizing a CuI reagent. Using DFT, the transformation to methanol (CH3OH) from methane (CH4) was examined. The transition metal systems studied for this transformation included a model FeII complex. This first-row transition metal is an economical, Earth-abundant metal. The ligand set for this transformation includes a carbonyl ligand in one set of complexes as well as a phosphite ligand in another. The 3d Fe metal shows the ability to convert alkyls/aryls to their oxidized counterpart in an energetically favorable manner. Also, “superbasic” alkali metal amides were investigated to perform C—H bond cleavage. Toluene was the substrate of interest with Cs chosen to be the metal of interest because of the highly electropositive nature of this alkali metal. These highly electrophilic Cs metal systems allow for very favorable C—H bond scission with a toluene substrate. Finally, the amination and aziridination of C–H and C=C bonds, respectively, by a CuI reagent was studied. The mechanism was investigated using DFT calculations. Presently, these mechanisms involving the use of coinage metals are debated. Our DFT simulations shed some insight into how these transformations occur and ultimately how they can be manipulated.

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