• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 378
  • 202
  • 113
  • 83
  • 30
  • 29
  • 25
  • 10
  • 9
  • 8
  • 7
  • 6
  • 6
  • 6
  • 6
  • Tagged with
  • 1047
  • 114
  • 83
  • 83
  • 71
  • 69
  • 64
  • 56
  • 55
  • 54
  • 49
  • 45
  • 43
  • 43
  • 41
  • 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.
1

Studium dimerizace resveratrolu a izolace \kur{trans}-\recke{varepsilon}-viniferinu

TOUPAL, Lukáš January 2016 (has links)
The theoretical part is focused on the preparation of the trans-resveratrol dimers, their occurrence in the plants and their isolation possibility with emphasis to trans-epsilon-viniferin. In the experimental part of master thesis the selected reagents, namely 2-hydroxy-1,4-naphthoquinone, tetrachloro-1,4-benzoquinone, laccase and ferric chloride, were studied with the aim of the trans-resveratrol dimer preparation. Furthermore, the Fenton reaction and its modification was also studied. Last part of this thesis is devoted to the trans-epsilon-viniferin isolation from grape cane by chromatographic methods.
2

Développement de nouveaux antagonistes de l’interleukine-15 / Development of new antagonits of interleukin-15

Meghnem, Dihia 09 December 2016 (has links)
L’IL-15 et l’IL-2 sont deux cytokines fonctionnellement très proches et sont nécessaires à l’activation et la prolifération des cellules immunitaires telles que les cellules NK et les lymphocytes T CD8+. Le rôle activateur de l’IL-15 et de l’IL-2 fait de celles-ci deux acteurs importants dans les maladies auto-immunes et les maladies inflammatoires. Dans cette étude, nous avons développé un premier antagoniste nommé NANTIL-15 qui se fixe au récepteur IL-15Ra mais ne recrute pas la chaîne IL-15Rb et inhibe spécifiquement l'IL-15. Le NANTIL-15 n’affecte pas l’homéostasie des cellules NK et des lymphocytes T CD8+ chez la souris. Dans un modèle murin d’arthrite, le NANTIL-15 réduit les signes cliniques et le recrutement des lymphocytes T CD8+ dans le site inflammatoire. Le deuxième antagoniste développé est nommé BiG et se fixe au récepteur IL-2/15Rb avec une haute affinité mais ne recrute pas la chaîne IL-2/15Rg. BiG inhibe les fonctions effectrices de l’IL-15 et de l’IL-2 sur les cellules NK et les lymphocytes T CD8+. En présence de la chaîne IL-2Ra, BiG n’a aucun impact sur les fonctions de l’IL-2 sur les cellules T-reg. Ainsi BiG favorise le ratio régulateur/effecteur du système immunitaire. Dans un modèle murin de greffe de peau, BiG permet de ralentir le rejet des greffons. Enfin des travaux réalisés sur la lignée de cellules humaines NK-92 et les cellules NK humaines primaires, ont permis de mettre en évidence une « trans-présentation homotypique » de l’IL-15. En effet les cellules NK chargées avec l’IL-15 et non l’IL-2, trans-présentent cette IL-15 aux cellules NK voisines. Ce travail a également montré que cette trans-présentation homotypique est dépendante du contact physique entre les cellules et impliquerait les molécules d’adhésion tel que LFA-1. / L’IL-15 et l’IL-2 sont deux cytokines fonctionnellement très proches et sont nécessaires à l’activation et la prolifération des cellules immunitaires telles que les cellules NK et les lymphocytes T CD8+. Le rôle activateur de l’IL-15 et de l’IL-2 fait de celles-ci deux acteurs importants dans les maladies auto-immunes et les maladies inflammatoires. Dans cette étude, nous avons développé un premier antagoniste nommé NANTIL-15 qui se fixe au récepteur IL-15Ra mais ne recrute pas la chaîne IL-15Rb et inhibe spécifiquement l'IL-15. Le NANTIL-15 n’affecte pas l’homéostasie des cellules NK et des lymphocytes T CD8+ chez la souris. Dans un modèle murin d’arthrite, le NANTIL-15 réduit les signes cliniques et le recrutement des lymphocytes T CD8+ dans le site inflammatoire. Le deuxième antagoniste développé est nommé BiG et se fixe au récepteur IL-2/15Rb avec une haute affinité mais ne recrute pas la chaîne IL-2/15Rg. BiG inhibe les fonctions effectrices de l’IL-15 et de l’IL-2 sur les cellules NK et les lymphocytes T CD8+. En présence de la chaîne IL-2Ra, BiG n’a aucun impact sur les fonctions de l’IL-2 sur les cellules T-reg. Ainsi BiG favorise le ratio régulateur/effecteur du système immunitaire. Dans un modèle murin de greffe de peau, BiG permet de ralentir le rejet des greffons. Enfin des travaux réalisés sur la lignée de cellules humaines NK-92 et les cellules NK humaines primaires, ont permis de mettre en évidence une « trans-présentation homotypique » de l’IL-15. En effet les cellules NK chargées avec l’IL-15 et non l’IL-2, trans-présentent cette IL-15 aux cellules NK voisines. Ce travail a également montré que cette trans-présentation homotypique est dépendante du contact physique entre les cellules et impliquerait les molécules d’adhésion tel que LFA-1.
3

Effect of chitosan on epithelial cell tight junctions

Smith, Jennifer Margaret January 2002 (has links)
No description available.
4

Lipid analysis of Phaeodactylum tricornutum in response to trans trans 2,4 decadienal stress

Byrwa, Brian Christopher 27 February 2012 (has links)
Considering the nature of increasing global temperatures associated with elevated atmospheric carbon dioxide levels as a result of increased demand for energy, it is notable to consider viable options to reduce the strain that these increased carbon dioxide emissions are having on the overall impact of the global climate. Phaeodactylum tricornutum, a marine phytoplankton may be utilized to this end. Its unique ability to increase lipid production under environmental stress conditions, in particular those lipids that can easily be converted into biodiesel, make it an ideal candidate for this use. Here, we examine the effects of trans trans 2,4 decadienal (or DD for short), an aldehyde that is known to induce cell death in the diatom at high concentrations, as they relate to changes in the lipid biosynthesis pathway. 100 ml Axenic cultures of the diatom P. tricornutum were grown to exponential stage, harvested and treated with decadienal at a concentration of 5[mu]g/ml to determine effects on lipid production after 24 hours. Qualitative analysis undertaken using Nile red staining of treated and untreated cells indicated increased fluorescence of treated cells compared to unstained water controls, however this increase may not be attributable to increased lipid production due to the fact that cells were unfixed and must be verified through other means. Initial attempts to verify this finding through thin layer chromatography and qPCR were inconclusive. / text
5

Le choix du prénom chez le trans / The choice of the first name in the trans

Núñez González, Elizabeth 29 November 2018 (has links)
Le choix du prénom chez le trans, s’agit d’une thèse qui fait des approches à la question trans à partir de la clinique psychanalytique proposée par Sigmund Freud et Jacques Lacan.À la question principale sur laquelle repose cette recherche –comment une personne peut-elle changer de prénom (et de sexe ou de genre) ? –, s'y ajoute une autre, qui vise à se demander s’il est justifié ou non –et pourquoi– de continuer à faire une différenciation structurelle basée sur les critères de la psychanalyse.Dans la tension entre ces deux questions réside tout l’effort de l’auteure pour parvenir à une réflexion qui se réfère à la théorie psychanalytique mais qui prend racine dans ce qui interroge la théorie, voire la conteste, c’est à dire la complexité des rencontres cliniques avec des personnes trans.L’ensemble de la recherche s’appuie sur trois ensembles de travaux : la psychiatrie et la théorie queer des États-Unis ; la psychiatrie, la sexologie et le féminisme du Mexique, et la psychanalyse de France. Spécifiquement par rapport à l’enseignement de Lacan, considérant que la caractéristique du travail fait appel à la question du choix du prénom, la période à laquelle se circonscrit la thèse va de 1961 –l'année où il a commencé son séminaire L’identification– à 1965 –celle consacrée aux Problèmes cruciaux de la psychanalyse–, période au cours de laquelle Lacan travaille davantage sur la question du nom propre. Cette délimitation n'exclut pas, cependant, lorsqu'il a été nécessaire, de faire des liens vers d'autres moments de son enseignement, en tenant compte de leur contexte et de leur pertinence pour le développement.L'ensemble se compose de huit chapitres, divisés en deux sections : dans la première, du chapitre un au chapitre quatre, est développé le cadre théorique ; dans la deuxième, du chapitre cinq au chapitre huit, est développé le thème du prénom et son choix chez les trans / The choice of the first name in the trans, is a thesis that makes approximations to the trans question from the psychoanalytic clinic proposed by Sigmund Freud and Jacques Lacan.To the main question that gives rise to this investigation - how is it that a person can change their name (and sex / gender)? -, one more is added, which aims to ask whether it is justified or not -and why- continue making a structural differentiation based on the criteria of psychoanalysis.In the tension between these two questions lies the author's effort to formulate a reflection that refers to psychoanalytic theory but that takes root in what interrogates the theory, and even discusses it based on the complexity of clinical encounters with transgender people. The whole of the research is based on three working groups: psychiatry and queer theory of the United States; psychiatry, sexology and feminism of Mexico, and psychoanalysis of France.Specifically in relation to the teaching of Lacan, considering that the specificity of the work appeals to the question of the choice of the first name, the period to which it is circumscribed goes from 1961 -Year in which his seminar begins, The identification- to 1965 -that dedicated to the crucial problems for psychoanalysis-, a period in which Lacan works with greater emphasis, the question of the proper name. This necessary delimitation does not exclude, however, when it was necessary, the presence of links to other moments of its teaching, taking into account the context of them and the pertinence within the development.The structure of this research consists of eight chapters, which are divided into two sections: from the first to the fourth, the theoretical elements - theoretical framework - that will support the second section, which goes from chapter five to eight, where it is specifically developed the theme of the first name and its choice in trans people
6

Polyprotein processing in caliciviruses

Bromfield, Annabel January 2002 (has links)
No description available.
7

Ferriin oxidation of benzylic 1,2-diols a mechanistic approach /

Liu, An. January 1999 (has links)
Thesis (Ph. D.)--West Virginia University, 1999. / Title from document title page. Document formatted into pages; contains xii, 96 p. : ill. Includes abstract. Includes bibliographical references.
8

Caracterização estrutural da proteína spliceosomal de Trypanosoma brucei U5-15K / Structural characterization of Trypanosoma brucei\'s spliceossomal protein U5-15K

Lima, Ana Laura de 23 February 2015 (has links)
A doença do sono é um dos maiores obstáculos para o desenvolvimento das áreas rurais da África Subsaariana. O diagnóstico positivo da doença do sono, bem como o estágio em que ela se encontra, é essencial perante a severidade da doença e toxicidade dos medicamentos disponíveis para o tratamento. A eficiência do tratamento e diagnóstico depende do conhecimento do ciclo de vida, biologia do parasito e seu metabolismo. Os tripanossomatídeos possuem mecanismos conservados entre si como a expressão gênica, neste contexto o Trypanosoma brucei pode ser considerado um organismo modelo e o estudo do processamento de RNA mensageiro por splicing neste parasito pode ser extrapolado para outros tripanosomatídeos. O processo de excisão dos íntrons e junção dos éxons é chamado splicing, e tanto o cis quanto o trans-splicing são reações de transesterificação realizados pelo spliceosomo, que consiste de 5 partículas nucleares, as snRNPs (small nuclear ribonucleoprotein) U1, U2, U4, U5 e U6 bem como proteínas não específicas de snRNPs. As snRNPs são complexos que consistem de pequenos RNAs ricos em uridina (U snRNAs) unidos fortemente a proteínas. São conhecidas oito proteínas específicas de U5 snRNP em humanos 220K, 200K, 116K, 102K, 100K, 52K, 40K e 15K. Foi mostrado que a U5-15K humana é essencial em diversos pontos da formação do spliceosomo. O objetivo desse trabalho foi a caracterização estrutural e da atividade de autoclivagem da proteína U5-15K de T. brucei. Essa proteína pertencente à família Dim1e é formada por 155 resíduos de aminoácido e massa molecular de 17,7 kDa. A proteína recombinante clonada no vetor de expressão pET SUMO (Invitrogen) foi expressa em E. coli por indução com IPTG e purificada por cromatografia de afinidade por íons metálico em resina de Cobalto. O produto foi usado para testes da atividade de auto-clivagem, contendo ou não inibidores de protease. A proteína pura também foi usada em estudos de suas propriedades em solução por experimentos de DLS, que mostrou uma maior homogeneidade da proteína na presença de MgCl2, DSF, que mostrou a estabilidade da U5-15K em solução com relação ao pH. As mudanças de conformação da estrutura secundária da U5-15K e U5-15K clivada foi estudada por experimentos de CD, que mostraram uma redução na porcentagem de folhas-β na estrutura terciária da U5-15K clivada, e foi construído um modelo tridimensional através da modelagem por homologia, que foi comparado com os resultados obtidos por experimentos de SAXS. Foram realizados ensaios de cristalização em diversas condições provenientes de kits comerciais com a proteína nas formas clivada e não clivada e em diferentes concentrações. Como perspectivas ficam a definição exata do ponto de clivagem por espectrometria de massas, proteólise da alça flexível para novos ensaios de cristalização e estudo das mutações nos possíveis sítios ativos e sítio de clivagem. / Sleep sickness is one the most important public health problem in the Africa and it causative agent, Trypanosma brucei, is an organism model for the study of different conserved process among the trypanosomatids. In trypanosomes, mRNAs are processed by trans-splicing, in which a common spliced leader sequence (SL) is acquired at the 5\' end of the mRNA to yield a mature transcript. RNA splicing is carried out by the spliceosome, which consists of the U1, U2, U4, U5 and U6 U snRNPs particles and non-snRNP proteins. The ribonucleoproteins are complexes that consist of small uridine-rich RNAs (U snRNAs) and interact with common Sm proteins and proteins that are specific for each snRNP. Seven U5 snRNP specific proteins are known in trypanosomes, 220K, 200K, 116K, 102K, Cwc21, 40K e 15K. The spliceosomal protein U5-15K is essential for the parasite viability and various evidences suggest participation of the member in spliceosome assembly. U5-15K presents a conserved domain dim1, its molecular weight is estimated of 17,7 kDa and 155 amino acids residues. In this work, U5-15K was cloned into pET SUMO (Invitrogen), transformed in BL21(DE3)pLysS and recombinant protein was purified by immobilized ion affinity chromatography. It was possible observe that U5-15K undergo self-cleavage, process inhibited by serine and cysteine protease inhibitors. Dynamic Light Scattering (DLS) experiments showed higher protein homogeneity in the presence of MgCl2 and Differential Scanning Fluorimetry (DSF) data demonstrated higher stability at neutral pH. Circular dichroism (CD) spectra obtained using U5-15K native and cleaved suggest a reduction in percentage of β-sheets at cleaved U5-15K secondary structure. Native and cleaved proteins at different concentrations were used in crystallization trials, however, no suitable protein crystals were observed. A tridimensional homology model for U5-15K from Trypanosoma brucei, using as template the human homologue, present a thioredoxin folding, although it has observed a possible central loop not present in the template. We intent to determine the exact cleavage point using mass spectrometry and new crystallization trials will be performed after removal of probable loops by limited proteolysis.
9

As corajosas: etnografando experiências travestis na prostituição / The Brave: etnographing transvestites experiences in prostitution

Patriarca, Letizia 13 November 2015 (has links)
Esta dissertação parte de experiências de travestis que são também profissionais do sexo para focar nas relações que estabelecem com donas de casas de prostituição. Há uma atenção para o fazer antropológico, percorrendo as construções das vivências das travestis que se prostituem, perpassando marcadores sociais da diferença a saber, gênero, sexualidade, classe, raça e geração. Em um primeiro momento, surgem as diversas construções identitárias das que circulam pelo bairro Jardim Itatinga (Campinas SP), para depois percorrer a especificidade deste. Estruturado por uma variedade de casas de prostituição, sua dinâmica engendra determinadas vivências do trabalho sexual ali realizado, que permite repensar relações com as donas de casas de prostituição, especificamente das experiências de travestis em casas de prostituição. A hipótese percorrida é a de que donas e suas casas de prostituição podem ser um suporte econômico-afetivo para construções identitárias do universo trans, assim como representam um apoio seguro diante de violências policiais e de clientes que acometem suas vivências na prostituição. / This dissertation is based on the experiences of transvestites who are also sex workers in order to focus on the relationships they establish with madams, brothels owners. Attention is paid to the anthropological doing, covering the experiences buildings of transvestite prostitutes, passing through social markers of difference - namely, gender, sexuality, class, race and generation. In a first moment, the various identity constructions of those who circulate around Jardim Itatinga (Campinas SP) are brought to discussion, and then the specificity of this neighborhood is handled. Structured by a variety of brothels, its dynamic engenders certain experiences of the sexual work performed there, allowing the rethinking of the relations with the brothels owners, specifically the experiences of transvestites in such establishments. The hypothesis sustained is that madams and their brothels can be an economic and emotional support for the identity constructions of the trans universe, at the same time that they represent a secure support in the face of police and customers violence that affect their experiences in prostitution.
10

Petrology of the Mitchell Mesa Rhyolite, Trans-Pecos Texas

Burt, Edward R. 18 February 2015 (has links)
An ash-flow sheet, to which the names Mitchell Mesa Rhyolite and Brite Ignimbrite have been applied, crops out prominently in Presidio and western Brewster Counties, Texas. Because of its great areal extent it is the most important unit for correlation in the Tertiary volcanic field of southern Trans-Pecos Texas, and it should bear a single name. Priority and widespread use in published literature support the name Mitchell Mesa. The ash-flow sheet is divisible into two cooling-units. The lower, a simple cooling-unit that grades locally into a compound cooling-unit, is a vitric-crystal rhyolitic ash-flow tuff with 15 to 25 percent opalescent alkali feldspar and bipyramidal quartz phenocrysts as long as 4 mm in a light brownish gray, grayish pink, or light gray vesiculated groundmass. The lower cooling-unit ranges in thickness from about 230 feet immediately north of Pinto Canyon to 2 feet at South Lajitas Mesa. The upper, simple cooling-unit is a vitric-lithic ash-flow tuff with as much as 20 percent lithic fragments in a very light gray to brownish gray groundmass containing about 10 percent non-opalescent alkali feldspar and quartz phenocrysts. The upper unit ranges in thickness from 60 to 100 feet. Its only outcrops are overlain by Petan Basalt north and northeast of Pinto Canyon. Except in a few places, the pyroclastic texture of the lower cooling-unit was obliterated by vapor-phase crystallization. Any tridymite and cristobalite originally present were subsequently converted to quartz. Four whole-rock chemical analyses of samples from widely separated localities are similar, showing only minor variations in K₂o and Na₂o. The alkali feldspar phenocrysts are richer in Na₂O and poorer in K₂O than the whole rock. Therefore the feldspar in the groundmass is more potassic than that in the phenocrysts. Foreign inclusions are most abundant in outcrops of Mitchell Mesa Rhyolite closest to the Chinati Mountains. Immediately north of the mountains, a separate ash-flow tuff is present beneath the Mitchell Mesa Rhyolite. This and other evidence leads to the conclusion that the Chinati Mountains area was the source of the ash-flow sheet. / text

Page generated in 0.0604 seconds