In the canon of twentieth century American poetry, "long poems" or "anti-epics" or epic poems represent a formidable genre. Defining epic poetry has proved difficult in our modern era, and the possibility that women might write epics is not often considered. This study includes a review of the literature that may define the epic genre and of the literature that contributes to our understanding of a tradition of women's poetry in American literature. The review of both issues--possible epic poetry and women's poetic tradition--is a necessary prerequisite for considering the argument that H.D.'s iielen in Eavpt and Gwendolyn Brooks's In the Mecca are twentieth century epics. With the focus on a female heroine, on personal and interpersonal values, and on a reconsideration of cultural lieroism, these poems are important literary contributions in addition to being "revised" epics.A revision of the epic signifies that the poet has found a way to accomplish individual expression in this familiar genre, a genre characterized by narration, cultural themes that may be didactic, and multiple voices for the poet. H.D. and Brooks have revised the genre of epic poetry in unusual ways. H.D. has taken a legendary figure, Helen of Troy, and made her the primary speaker and the seeker of truth. Instead of the classical glorification of war, Helen's quest includes a renunciation of war and a reconsideration of the ways we know ourselves and our history. Brooks has made an "unknown" black woman the center of her urban epic. Mrs. Sallie's quest, initiated by the real search for a missing daughter, becomes a quest for the meaning of family, community, and selfhood.Revising the genre was a unique process for both H.D. and Brooks, and studying Helen and Mecca together emphasizes the diverse traditions--literary and nonliterary--that may elucidate our understanding of each poem. Moreover, only refers to a "a genre revised" by H.D. and Brooks not only refers to a revision of epic poetry but to poetry as a whole. Each woman created her own blend of "traditions and individual talent" in order to produce Helen in Egypt and In the Mecca. / Department of English

Thesis (Ph. D.)--University of Washington, 1999. / Vita. Includes bibliographical references (leaves 229-240).

Thèse numérisée par la Direction des bibliothèques de l'Université de Montréal.

Les transporteurs d'ADP/ATP (Ancp) et de phosphate inorganique (PiC) ainsi que la porine VDAC représentent les principaux maillons d'une machinerie de transport d'ADP, d'ATP et de phosphate inorganique à travers la double membrane mitochondrial. Actuellement, les connaissances relatives aux mécanismes moléculaires mis en jeu dans cette machinerie accusent un retard. L'objectif de ce projet de Thèse a été d'amener de nouveaux éléments sur l'état conformationnel de ces protéines étudiées dans la levure Saccharomyces cerevisiae, modèle biologique où la génétique est facilitée. La majeure partie de ce projet a concerné l'Ancp de levure qui assure l'échange d'ADP cytosolique contre de l'ATP matriciel néosynthétisé suite aux processus de phosphorylation oxydative. Il peut être inhibé spécifiquement par deux poisons naturels, le carboxyatractyloside (CATR) et l'acide bongkrékique (BA) qui stabilisent la protéine dans deux états conformationnels distincts adoptés lors du mécanisme de transport. Afin de mieux comprendre cette dynamique, une étude comparative des deux conformères a été réalisée en combinant l'échange hydrogène/deutérium couplé à la spectrométrie de masse (HDX-MS) aux outils biochimiques directement liés à l'étude des Ancp. Les résultats obtenus corrèlent l'hypothèse d'une structure malléable du transporteur dans laquelle des changements conformationnels importants interviennent. D'autre part, ce projet a permis d'obtenir les premières données d'accessibilité au solvant du PiC. Enfin, l'étude en HDX-MS de VDAC, nous a permis de montrer que son accessibilité au solvant en solution de détergent était en accord avec les données structurales publiées récemment.

To investigate how protein folding is affected by sequence connectivity five topological variants of the ribosomal protein S6 were constructed through circular permutation.  In these constructs, the chain connectivity (i.e. the order of secondary-structure elements) is changed without changing the native-state topology.  The effects of the permutations on the folding process were then characterised by φ-value analysis, which estimates the extent of contact formations in the transition-state ensemble.  The results show that the folding nuclei of the wild-type and permutant proteins comprises a common motif of one α-helix docking against two β-sheets, i.e. the minimal structure for folding.  However, this motif is recruited in different parts of the S6 structure depending on the permutation, either in the α1 or α2 half of the protein.  This minimal structure is not unique for S6 but can also be seen in other proteins.  As an effect of the dual nucleation possibilities, the transition-state changes describe a competition between two parallel pathways, which both include the central β-stand 1.  This strand constitutes thus a structural overlap between the two competing nuclei.  As similar overlap between competing nuclei is also seen in other proteins, I hypothesise that the coupling of several small nuclei into extended ‘super nuclei’ represents a general principle for propagating folding cooperativity across large structural distances.  Moreover, I demonstrate by NMR analysis that the existence of multiple folding nuclei renders the H/D-exchange kinetics independent of the folding pathway. / At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper IV: Manuscript

Les champignons produisent une grande variété de composés/métabolites biologiquement actifs qui peuvent être utilisés à des fins médicinales et pharmaceutiques. Les mitorubrines, membres de la famille des azaphilones, constituent un ensemble particulièrement intéressant de métabolites secondaires, présentant une grande étendue d'activités biologiques (e.g. antimicrobienne, antibactérienne, antipaludique). Ce travail présente le développement de plusieurs approches de spectrométrie de masse permettant de résoudre la diversité structurelle naturelle et la complexité des azaphilones extraits des champignons Hypoxylon fragiforme. La première partie de ce manuscrit est dédiée au développement et à la validation d'une méthodologie analytique impliquant la chromatographie liquide couplée à la spectrométrie de masse haute résolution pour la détection efficace et précise de traces d'azaphilones dans des extraits fongiques complexes. En outre, des expériences de spectrométrie de masse en mode tandem (par dissociation induite par collision, CID) et d'échange hydrogène/deutérium ont été effectuées pour élucider et caractériser les azaphilones et leurs analogues azotés chez Hypoxylon fragiforme. La deuxième partie est consacrée à l'application de ces différentes stratégies analytiques pour la caractérisation approfondie d'une nouvelle famille de métabolites secondaires dérivés des azaphilones, les mitorubramines. Enfin, ces différents métabolites secondaires ont été purifiés pour confirmer leur structure chimique par spectroscopie RMN

Thesis (Ph. D.)--State University of New York at Binghamton, Department of English, 2007. / Includes bibliographical references.

<p>Dimerization and oligomerization reactions of alkenes are promising catalytic strategies to convert light alkenes, which can be derived from light alkane hydrocarbons (ethane, propane, butane) abundant in shale gas resources, into heavier hydrocarbons used as chemical intermediates and transportation fuels. Nickel cations supported on aluminosilicate zeotypes (zeolites and molecular sieves) selectivity catalyze ethene dimerization over oligomerization given their mechanistic preference for chain termination over chain propagation, relative to other transition metals commonly used for alkene oligomerization and polymerization reactions. Ni-derived sites initiate dimerization catalytic cycles in the absence of external activators or co-catalysts, which are required for most homogeneous Ni complexes and Ni²⁺ cations on metal organic frameworks (MOFs) that operate according to the coordination-insertion mechanism, but are not required for homogeneous Ni complexes that operate according to the metallacycle mechanism. Efforts to probe the mechanistic details of ethene dimerization on Ni-containing zeotypes are further complicated by the presence of residual H⁺ sites that form a mixture of 1-butene and 2-butene isomers in parallel acid-catalyzed pathways, as expected for the coordination-insertion mechanism but not for the metallacycle mechanism. As a result, the mechanistic origins of alkene dimerization on Ni cations have been ascribed to both the coordination-insertion and metallacycle-based cycles. Further, different Ni site structures such as exchanged Ni²⁺, grafted Ni²⁺ and NiOH⁺ cations are proposed as precursors to the dimerization active sites, based on analysis of kinetic data measured in different kinetic regimes and corrupted by site deactivation, leading to unclear and contradictory proposals of the effect of Ni precursor site structures on dimerization catalysis.</p> <p> Dimerization of ethene (453 K) was studied on Ni cations exchanged within Beta zeotypes in the absence of externally supplied activators, by suppressing the catalytic contributions of residual H⁺ sites via selective pre-poisoning with Li⁺ cations and using a zincosilicate support that contains H⁺ sites of weaker acid strength than those on aluminosilicate supports. Isolated Ni²⁺ sites were predominantly present, consistent with a 1:2 Ni²⁺:Li⁺ ion-exchange stoichiometry, CO infrared spectroscopy, diffuse reflectance UV-Visible spectroscopy and <i>ex-situ</i> X-ray absorption spectroscopy. Isobutene serves a kinetic marker for alkene isomerization reactions at H⁺ sites, which allows distinguishing regimes in which 2-butene isomers formed at Ni sites alone, or from Ni sites and H⁺ sites in parallel. 1-butene and 2-butenes formed at Ni sites were not equilibrated and their distribution was invariant with ethene site-time, revealing the primary nature of butene double-bond isomerization at Ni sites as expected from the coordination-insertion mechanism. <i>In-situ</i> X-ray absorption spectroscopy showed that the Ni oxidation state was 2+ during dimerization, also consistent with the coordination-insertion mechanism. Moreover, butene site-time yields measured at dilute ethene pressures (<0.4 kPa) increased with time-on-stream (activation transient) during initial reaction times, and this activation transient was eliminated at higher ethene pressures (≥ 0.4 kPa) and while co-feeding H₂. These observations are consistent with the <i>in-situ</i> formation of [Ni(II)-H]⁺ intermediates involved in the coordination-insertion mechanism, as verified by H/D isotopic scrambling and H₂-D₂ exchange experiments that quantified the number of [Ni(II)-H]⁺ intermediates formed.</p> <p> The prevalence of the coordination-insertion cycles at Ni²⁺ cations provides a framework to interpret the kinetic consequences of the structure of Ni²⁺ sites that are precursors to the dimerization active sites. Beta zeotypes predominantly containing either exchanged Ni²⁺ cations or grafted Ni²⁺ cations show noteworthy differences for ethene dimerization catalysis. The deactivation transients for butene site-time yields on exchanged Ni²⁺ cations indicate two sites are involved in each deactivation event, while those for grafted Ni²⁺ cations indicate involvement of a single site. The site-time yields of butenes extrapolated to initial time, and then further extrapolated to zero ethene site-time, rigorously determined initial ethene dimerization rates (453 K, per Ni) that showed a first-order dependence in ethene pressure (0.05-1 kPa). This kinetic dependence implies the β-agostic [Ni(II)-ethyl]⁺complex to be the most abundant reactive intermediate for the Beta zeolites containing exchanged and grafted Ni²⁺ cations. Further, the apparent first-order dimerization rate constant was two orders of magnitude higher for exchanged Ni²⁺ cations than for grafted Ni²⁺ cations, reflecting differences in ethene adsorption or dimerization transition state free energies at these two types of Ni sites. </p> <p> The presence of residual H⁺ sites on aluminosilicate zeotypes, in addition to the Ni²⁺ sites, causes formation of saturated hydrocarbons and oligomers that are heavier than butenes and those containing odd numbers of carbon atoms. The reaction pathways on Ni²⁺ and H⁺ sites are systematically probed on a model Ni-exchanged Beta catalyst that forms a 1:1 composition of these sites <i>in-situ</i>. The quantitative determination of apparent deactivation orders for the decay of product space-time yields provides insights into the site origins of the products formed. Further, Delplot analysis systematically identifies the primary and secondary products in the reaction network. This strategy shows linear butene isomers to be primary products formed at Ni²⁺-derived sites, while isobutene is formed as a secondary product by skeletal isomerization at H⁺ sites. In addition, propene is formed as a secondary product, purportedly by cross-metathesis between linear butene isomers and the reactant ethene at Ni²⁺-derived sites. Also, ethane is a secondary product that forms by hydrogenation of ethene at H⁺ sites, with the requisite H₂ generated <i>in-situ</i> likely by dehydrogenation and aromatization of ethene at H⁺ sites.</p> <a>The predominance of the coordination-insertion mechanism at Ni²⁺-derived sites implies kinetic factors influence isomer distributions within the dimer products, providing an opportunity to influence the selectivity toward linear and terminal alkene products of dimerization. In the case of bifunctional materials, reaction pathways on the Ni²⁺ and H⁺sites dictate the interplay between kinetically-controlled product selectivity at Ni sites and thermodynamic preference of product isomers formed at the H⁺ sites. </a>In summary, through synthesis of control catalytic materials and rigorous treatment of transient kinetic data, this work presents a detailed mechanistic understanding of the reaction pathways at the Ni²⁺ and H⁺ sites, stipulating design parameters that have predictable consequences on the product composition of alkene dimerization and oligomerization.

Le domaine de la bioénergie moléculaire concerne le transfert et le stockage d’énergie dans les cellules biologiques. Ce projet s’articule autour de la respiration et plus précisément le mécanisme de pompage de sodium et de protons, et son couplage au transfert d’électrons. Premièrement, nous nous sommes intéressés au pompage d’ions sodium par la NADH : quinone oxidoreductase de la bactérie Vibrio cholerae. L’importance de flavines spécifiques et des résidus acides dans le transfert de sodium ont été démontrée. Par la suite, l’interaction entre protéines, notamment le cytochrome c552 et le fragment CuA de l’oxidase de type ba3 de l’organisme Thermus thermophilus a été étudié. Une réorganisation structurelle induit par le transfert d’électron a été démontrée par la spectroscopie IRTF différentielle. Enfin, dans la dernière partie de ce travail, l’interaction au sein du supercomplex bc1-aa3 de la chaîne respiratoire du Corynebacterium glutamicum a été analysée. / The field of molecular bioenergetics deals with the energy transduction in biological cells. In this project, respiration and more specifically proton and sodium pumping enzymes and their coupling to electron transfer have been in focus. First we have been interested in the Na+-pumping NADH:quinone reductase from Vibrio cholerae which is the entry site of electrons in the respiratory chain of several pathogens. The role of specific flavin cofactors and amino acids involved in Na+ transfer has been shown in a combined IR spectroscopic and electrochemical approach. The interaction between proteins, namely the cytochrome c552 and the CuA fragment from the terminal ba3 oxidase from the organism Thermus thermophilus was then investigated. Structural reorganization during electron transfer was revealed by IR spectroscopy. Finally, in the third part of the project the interaction within the bc1-aa3 supercomplex from the respiratory chain from Corynebacterium glutamicum was analyzed.

Historically, women have not been "speaking subjects" but "spoken objects" in Western culture--the ground on which male-dominated constructions have been erected. In literature, women have been conventionally held as the silent and silenced other. Lyric poetry especially has idealized not only the entrenched figures of masculine subject/feminine object, but poetry itself as the site of prophecy, vision, Truth. Most dramatically in lyric poetry then, the issue of women as subjects has been collapsed into Woman as object, that figure who has been the sacrifice necessary for the production of lyric "song" and the consolidation of the unified masculine voice. It has thus been difficult for women poets to take up the position of speaking subject, most particularly because of women's problematic relationship to Woman. Recent feminist theorists have explored female subjectivity, how women put into hegemonic discourse "a possible operation of the feminine." This dissertation analyzes that possibility in poetry as exemplified in the works of Emily Dickinson, Marianne Moore, and H.D. I contend that these paradigmatic American poets constitute speaking subjects in their poetry that both figure Woman conventionally and reconfigure it, i.e. subvert the stability of those representations, thereby disturbing our view. I argue that this double identification produces, in effect, a divided or split subjectivity that is enabling for the female speaker. As an alternative to the traditionally specularized figure of Woman then, such a position opens up distinctly counter-hegemonic spaces in which to constitute the female subject, rendering problematic readerly consumption of the image of Woman as a totality. I explore the attempts to represent women's difference differently--the tenuous accession to, rejection of, or play with the lyric "I" in these poets' works. Dickinson, Moore, and H.D. reconfigure Woman and inscribe female speakers as grammatically and rhetorically, but not necessarily visually, present, thereby frustrating patriarchal economies of mastery and possession.