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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.
61

Synthesis And Characterization Of Poly(oxalic Acid Dithiophen-3-yl Methyl Ester) And Thiophene Ended Poly-&amp / #949 / -caprolactone

Kerman, Ipek 01 May 2004 (has links) (PDF)
Synthesis and characterization of thiophene ended poly-&amp / #949 / -caprolactone (PCL) and oxalic acid dithiophen-3-yl methyl ester (ODME) and their copolymers with both pyrrole and thiophene were achieved. Chemical structure of the precursor polymer and monomer were investigated Redox behavior of polymer and monomers were determined by Cyclic Voltammetry (CV). Structural characterization of samples were carried out by 1H, 13C Nuclear Magnetic Resonance (NMR) and Fourier Transform Infrared Spectroscopy (FTIR). Conductivities of the films were measured by using four probe technique. Thermal analyses of conducting copolymers were investigated via Differential Scanning Calorimetry (DSC) and Thermal Gravimetry Analysis (TGA). The morphologies of the copolymer films were examined by Scanning Electron Microscopy (SEM). Electrochromic and spectroelectrochemical behavior of the copolymers were investigated, and their ability of employment in device construction has been examined.
62

Synthesis Of 1,2,3,5-tetrasubstituted Pyrrole Derivatives Via 5-exo-dig Type Cyclization And Stereoselective Functionalisation Of Ferrocene Derivatives

Kayalar, Metin 01 January 2005 (has links) (PDF)
ABSTRACT SYNTHESIS OF 1,2,3,5-TETRASUBSTITUTED PYRROLE DERIVATIVES VIA 5-EXO-DIG TYPE CYCLIZATION AND STEREOSELECTIVE FUNCTIONALISATION OF FERROCENE DERIVATIVES Metin Kayalar M.S., Department of Chemistry Supervisor: Prof. Dr. Ayhan S. Demir January 2005, 102 pages A convenient and new method for the synthesis of 1,2,3,5-tetrasubstituted pyrrole derivatives starting from 1,3,-dicarbonyl compounds through acid catalyzed cyclization reaction is described. Alkylation of 1,3-dicarbonyl compound with propargyl bromide followed by one step cyclization with the introduction of primary amines in the presence of catalytic amount of triflouroacetic acid (TFA) affords the corresponding pyrrole derivatives in high yields. The investigations on the studies of developing a new method for catalytic and stereoselective functionalisation of ferrocene derivatives were summarized. Functionalisation studies were carried out in three main strategy the first one of which is carboxylation, second one is arylation and the last one is oxidative cross-coupling with &amp / #945 / , &amp / #946 / -unsaturated carbonyl compounds.
63

Desenvolvimento de novas plataformas poliméricas para detecção eletroquímica de amônia e uréia / Development of new polymeric platforms for ammonia and urea electrochemical detection

Mariana Pereira Massafera 04 November 2010 (has links)
Este trabalho apresenta o desenvolvimento de (bio)sensores baseados em plataformas poliméricas convencionais e nanoestruturadas. Os sensores estudados contém poli(pirrol) como transdutor eletroquímico, responsável pela oxidação de amônia a 0,35 V. Como a enzima urease hidrolisa cataliticamente uréia a amônia, após a imobilização da enzima sobre o poli(pirrol), obtém-se um biossensor para detecção indireta de uréia, via amônia. A detecção de amônia pelo poli(pirrol) foi otimizada em termos da densidade de carga de poli(pirrol) presente no sensor, e do potencial de trabalho. Então verificou-se a ação do polímero poli(5-amino-1-naftol) na redução do sinal dos interferentes ácidos úrico e ascórbico. Após a otimização do sensor-base, estudou-se a influência do tipo de imobilização da urease ao substrato polimérico na sensibilidade e estabilidade do biossensor de uréia. Concluiu-se que a pouca quantidade de enzima imobilizada através das metodologias estudadas era o fator limitante da sensibilidade de detecção, e então implementou-se a nanoestruturação do poli(pirrol), para aumentar a área superficial disponível para a imobilização da urease. Preparou-se filmes de poli(pirrol) nanoestruturado (macroporoso e nanofios), e a compreensão dos fenômenos observados só foi possível ao aliar características geométricas e propriedades físico-químicas intrínsecas de sistemas nanoestruturados. / This work presents the development of (bio)sensors based on conventional and nanostructured polymeric platforms. The analyzed sensors contain poly(pyrrole) as electrochemical transducer, responsible for ammonia oxidation at 0.35 V. As the enzyme urease catalytically hydrolyses urea to ammonia, after enzyme immobilization onto poly(pyrrole), a biosensor for urea indirect detection, via ammonia, is obtained. Ammonia sensing by poly(pyrrole) was optimized in terms of both charge density of poly(pyrrole) present in the sensor and working potential. In sequence, poly(5-amino-1-naphtol) role as interferents (uric and ascorbic acids) signal blocker was verified. After optimization of the base-sensor, the influence of urease immobilization method on both detection sensitivity and biosensor durability was investigated. It was found that the small amount of enzyme immobilized using the compared methods limited detection sensitivities, and then nanostructuration of poly(pyrrole) was implemented, in order to increase the surface area available for urease immobilization. Nanostructured poly(pyrrole) films (macroporous and nanowires) were prepared, and the fully understanding of the observed phenomena was only possible combining geometric characteristics and physical-chemical properties related to nanostructured systems.
64

Biocélulas a combustível metanol e etanol/O2: preparação e caracterização de biocátodos / Methanol and ethanol/O2 biofuel cell: preparation and caracterization of biocathodes

Franciane Pinheiro Cardoso 02 July 2014 (has links)
Este trabalho descreve a preparação e caracterização de biocátodos para biocélula a combustível Etanol e Metanol//O2 utilizando a enzima lacase (trametes versicolor) num sistema de transferência eletrônica mediada (TEM). Na primeira etapa do trabalho, os resultados de cinética enzimática com a enzima lacase em solução e imobilizada sobre tecido de carbono mostraram que os vários parâmetros experimentais (pH, temperatura, estabilidade) analisados devem ser considerados, a fim de se obter atividade máxima com os biocatalisadores. Além disso, em relação aos testes cinéticos e de estabilidade, pode-se inferir que o dendrímero PAMAM pode ser empregado como um bom agente imobilizante na preparação de bicátodos para biocélula a combustível enzimática. Na segunda etapa do trabalho, uma semibiocélula Etanol//O2 foi testada e os eletrocatalisadores testados foram o verde de metileno (VM) e o azul de meldola (AM). Os testes de potência mostraram a importância da presença do mediador ABTS e do eletrocatalisador (VM) para melhorar o desempenho do dispositivo. Na terceira etapa do trabalho, eletrodos com diferentes mediadores (ABTS, ferro porfirina, ferroceno, complexo de ósmio e complexo de rutênio) e com polipirrol eletropolimerizado na superfície do eletrodo foram testados numa semibiocélula Metanol//O2. Os testes de semibiocélula Etanol e Metanol//O2 com transferência eletrônica mediada mostraram que os biocátodos preparados com o dendrímero PAMAM e com os diferentes eletrocatalisadores e mediadores, se mostraram capazes de gerar densidades de potência competitivas em relação aos valores encontrados na literatura. / This work describes the preparation and characterization of biocathodes for Ethanol and Methanol//O2 biofuel cell using the enzyme laccase (trametes versicolor) enzyme and mediated electron transfer (MET). Investigation of the enzymatic kinetics of the enzyme laccase in solution and immobilized onto carbon platforms showed that the analyzed experimental parameters (pH, temperature, and stability) must be considered for maximum activity to be achieved. The kinetic and stability tests revealed that PAMAM dendrimers constitute very good immobilization agent to prepare biocathodes for enzymatic biofuel cell. The second part of this work, dealt with Ethanol//O2half-cell using methylene green (MG) ormeldola blue (MB) as electrocatalyst. The power test evidenced that it is important to have ABTS as mediator and an electrocatalyst, to ensure that the device performs better. The third part of this work evaluated electrodes with distinct mediators (ABTS, iron porphyrin, ferrocene, osmium complex, and ruthenium complex) and containing electropolymerized polypyrrole on their surface in a Methanol//O2half-cell. Ethanol and Methanol//O2 half-cell tests with mediated electron transfer showed that the biocathodes prepared with PAMAM dendrimers, electrocatalyst, and distinct mediators generated competitive power densities as compared with literature data.
65

Dipirrometenos, 2-ariloilpirróis e derivados de bis-imidazol : síntese, caracterização e seus compostos de coordenação / Dipyrrins, 2-aryloylpyrroles and bis (imidazole) derivatives : synthesis, characterization and their coordination compounds

Gonsales, Stella de Almeida, 1987- 20 August 2018 (has links)
Orientadores: André Luiz Barboza Formiga, Pedro Paulo Corbi / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Química / Made available in DSpace on 2018-08-20T20:33:33Z (GMT). No. of bitstreams: 1 Gonsales_StelladeAlmeida_M.pdf: 5138050 bytes, checksum: 48050f171b28aaaec7dc54a01a7ee17f (MD5) Previous issue date: 2012 / Resumo: erivados de pirrol e imidazol, juntamente com seus complexos de Cu(II) e Zn(II). Após diversas tentativas de síntese do 5-fenildipirrometeno pela rota tradicional, obteve-se o produto desejado porém em baixíssimos rendimentos. Os 2-ariloilpirróis foram sintetizados com sucesso partindo-se de cloreto de ácido e pirrol, obtendo-se assim o 2-benzoil-3,5-dimetilpirrol (2-bz-pirrol) e o 2-isonicotinoil-3,5-dimetilpirrol (2-pypirrol) como produtos. Os compostos foram caracterizados por DRX de monocristal, MS, IV, UV-Vis e H e C RMN. Realizaram-se ensaios biol'ogicos com os ligantes obtidos, assim como com os complexos de Cu(II) destes ligantes. Outro ligante, tridentado, o 2,6-bis(imdazol-2-il)piridina (impy) foi sintetizado com sucesso e utilizado na síntese de um complexo inédito de cobre. Sua estrutura também foi determinada por difracão de raios X de monocristal, dentre outras técnicas, revelando uma estrutura binuclear não usual formada por uma ponte de cloreto / Abstract: In this work we present the synthesis of three new ligands derived from pyrrole and imidazole subunits, along with their Cu(II) and Zn(II) complexes. After many attempts to achieve the synthesis of 5-phenyldipyrromethene using the classical method, we obtained the desired product but in very low yields. Two 2- ariloylpyrroles have been synthesized from the acid chloride and pyrrole, achieving both 2-benzoyl-3,5-dimethylpyrrole (2-bz-pirrol) and 2-isonicotinoyl-3,5-dimethylpyrrole (2-py-pirrol) as products. These compunds were charactherized by single crystal XRD, MS, FTIR, UV-Vis and H e C NMR. Biological assays were performed with the obtained ligands and their Cu(II) complexes. Another ligand, tridentate, 2,6-bis(imdazole-2-yl)pyridine (impy) was successfully synthesized and used in the achievement of a novel Cu(II) complex. Its structure was also determined by single crystal XRD, among with other techniques, revealing an unusual chloride bridged binuclear structure / Mestrado / Quimica Inorganica / Mestre em Química
66

Chimie des acrylamides chiraux : nouvelles méthodologies et application à la synthèse de nouvelles architectures moléculaires / Chemistry of chiral acrylamides : new methodologies and application to the synthesisof new molecular architectures

Gratais, Alexandre 03 October 2014 (has links)
Les réactions permettant la création de liaisons carbone-carbone sont des outils essentiels dans le domaine de la synthèse organique. Elles permettent d'accéder à des structures de plus en plus complexes. Cependant le contrôle de ces réactions en utilisant des partenaires hautement fonctionnalisés reste un enjeu majeur.Le développement de nouvelles méthodologies de synthèse basées sur la réactivité des acrylamides chiraux dérivés d'acides aminés est étudié dans ces travaux. Une nouvelle version de la réaction d'alkylation de pyrroles de type Friedel-Crafts a été développée en utilisant le caractère électrophile d'acrylamides chiraux hautement fonctionnalisés. Le pyrrole peut être monoalkylé ou dialkylé de façon sélective conduisant à de nouvelles structures hétérocycliques portant des enchaînements peptidiques pouvant contenir jusqu'à quatre résidus d'acides aminés. Les acrylamides chiraux portant un motif allyltriméthylsilane conjugué ont été utilisés comme nouveaux réactifs permettant des réactions d'allylation hautement diastéréosélectives et chimiospécifiques vis-à-vis d'aldéhydes. L'extension de cette méthodologie aux aldéhydes α- aminés a été réalisée et permet un accès aisé à des structures analogues des acides γ-aminés. / Reactions allowing carbon-carbon bond creation are essential tools in the field of organic synthesis. These reactions are used to access to more and more complex structures. However their control in the case of highly functionnalized partners is still a serious concern.Development of new methodologies based on the reactivity of aminoacid derivating chiral acrylamides is reported. A new version of pyrrole alkylation reaction was developed using the electrophilic behaviour of highly functionnalized chiral acrylamides. Pyrrole can be selectivly monoalkylated or dialkylated leading to new heterocyclic structures bearing peptidic sequences containing up to four aminoacids residues. Chiral acrylamides bearing a conjuguated allyltrimethylsilane moiety have been used as new reagent in highly diastereoselective and chemospecific towards aldehydes allylation reactions. This methodology was extended to α-aminoaldehydes allowing easy access to γ-aminoacidsanalogues.
67

Toward Elucidating the Function of Non-canonical DNA Structures using Selective DNA-interacting Ligands / 選択的DNA結合性リガンドを用いた非標準型DNA構造の機能解明へ向けて

Asamitsu, Sefan 25 March 2019 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(理学) / 甲第21584号 / 理博第4491号 / 新制||理||1645(附属図書館) / 京都大学大学院理学研究科化学専攻 / (主査)教授 杉山 弘, 教授 秋山 芳展, 准教授 竹田 一旗 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DGAM
68

Elucidation of the Molecular Mechanisms of Gene Expressions-Epigenetics Regulation by Chemical Biology / ケミカルバイオロジーによる遺伝子発現-エピジェネティクス制御の分子機構の解明

Sato, Shinsuke 23 September 2020 (has links)
京都大学 / 0048 / 新制・論文博士 / 博士(理学) / 乙第13369号 / 論理博第1573号 / 新制||理||1666(附属図書館) / (主査)教授 杉山 弘, 教授 深井 周也, 教授 秋山 芳展 / 学位規則第4条第2項該当 / Doctor of Science / Kyoto University / DGAM
69

Development of Sequence-Specific DNA Binders for the Therapy of Mitochondrial Diseases / ミトコンドリア病根治薬を目指した塩基配列選択的DNA結合性化合物の開発

Hidaka, Takuya 23 March 2021 (has links)
京都大学 / 新制・課程博士 / 博士(理学) / 甲第23034号 / 理博第4711号 / 新制||理||1675(附属図書館) / 京都大学大学院理学研究科化学専攻 / (主査)教授 杉山 弘, 教授 深井 周也, 教授 秋山 芳展 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DGAM
70

Návrh a příprava nových derivátů 3-aroyl-1-arylpyrrolu jako potenciálních inhibitorů polymerizace tubulinu / Design and synthesis of novel 3-aroyl-1-arylpyrrole derivatives as potential tubulin polymerization inhibitors

Zenkerová, Katharina January 2020 (has links)
Charles University Faculty of Pharmacy in Hradec Králové Department of Pharmaceutical Chemistry and Pharmaceutical Analysis Author: Katharina Zenkerová Supervisors: Assoc. Prof. PharmD. Jan Zitko, Ph.D.; Prof. Romano Silvestri Title of diploma thesis: Design and synthesis of novel 3-aroyl-1-arylpyrrole derivatives as potential tubulin polymerization inhibitors Key word: anticancer agents; pyrrole; tubulin polymerization inhibitors Cancer is a major burden of disease worldwide and it remains one of the most difficult illnesses to treat. Since the percentage of people suffering from cancer is increasing, an enormous effort to design and develop better medicaments is needed. Microtubules are a key component of the cytoskeleton in most eukaryotic cells and they represent an attractive target for antitumor agents, due to the significant mitosis rate of tumor cells. Since cancer cells usually display higher proliferation rates than normal cells, drugs that interfere with microtubules dynamic equilibrium, also known as antimitotic agents, have become a fruitful approach to develop anticancer agents in clinical use. In fact, agents interfering with microtubules may either inhibit the tubulin polymerization or block microtubules to disassembly, both causing the arrest of cell division and the consequent...

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