1,911 research outputs found
Anticancer Activity, Reduction Mechanism and G-Quadruplex DNA Binding of a Redox-Activated Platinum(IV)–Salphen Complex
Get PDFAiming at reducing the unselective cytotoxicity of Pt(II) chemotherapeutics, a great deal
of effort has been concentrated into the design of metal‐containing drugs with different anticancer mechanisms of action. Inert Pt(IV) prodrugs have been proposed to be a valid alternative as they are activated by reduction directly into the cell releasing active Pt(II) species. On the other hand, a promising strategy for designing metallodrugs is to explore new potential biological targets rather than canonical B‐DNA. G‐quadruplex nucleic acid, obtained by self‐assembly of guanine‐rich nucleic acid sequences, has recently been considered an attractive target for anticancer drug design.
Therefore, compounds capable of binding and stabilizing this type of DNA structure would be greatly beneficial in anticancer therapy. Here, computational analysis reports the mechanism of action of a recently synthesized Pt(IV)–salphen complex conjugating the inertness of Pt(IV) prodrugs with the ability to bind G‐quadruplexes of the corresponding Pt(II) complex. The reduction mechanism of the Pt(IV) complex with a biological reducing agent was investigated in depth by means of DFT, whereas classical MD simulations were carried out to shed light into the binding mechanism of the released Pt(II) complex. The results show that the Pt(IV) prodrug may be reduced by both inner‐ and outer‐sphere mechanisms, and the active Pt(II) complex, as a function
of its protonation state, stabilizes the G‐quadruplex DNA prevalently, either establishing π‐stacking nteractions with the terminal G‐tetrad or through electrostatic interactions along with H‐bonds formation
Interaction of CO with PdAu(111) and PdAu(100) bimetallic surfaces: A theoretical cluster model study
No full textStructural parameters, binding energies, and bonding mechanism of CO molecules on PdAu(111) and PdAu(100) surface alloys have been investigated at the density functional level by employing a cluster model approach. Cluster models have been constructed to represent second-neighbor Pd pairs on both the exposed gold surfaces, given that special ensembles are able to confine reactants in a small region of bimetallic catalysts. Analysis of the cluster size dependence of the chemisorption properties has been carried out together with the study of the influence of exchange correlation functional and basis set quality. An accurate description of the bonding mechanism of CO on top of Pd monomers surrounded by gold atoms has been achieved by an atom-projected description of the surface bond. The remarkable agreement of computed results with available experimental information and previous periodic supercell calculations clearly indicates that the adopted cluster models are suitable for chemisorption studies on PdAu surface alloys. © 2008 American Chemical Society
The geometric effect in palladium-gold catalysis. Is the coupling the rate-determining step in the vinyl-acetate synthesis?
No full textFirst-principles calculations support the hypothesis that the appropriate spacing between Pd monomers controls the catalytic activity of Pd/Au catalysts in the vinyl acetate formation only if a vinyl surface species is involved in the rate-determining step of the reaction, opening new questions on these relevant catalytic systems. © 2009 The Royal Society of Chemistry
Adsorption of ethylene, vinyl, acetic acid, and acetate species on PdAu(111) and PdAu(100) surface alloys: A cluster model study
No full textThe adsorption properties on PdAu surface alloys of ethylene and acetic acid molecules along with their derived vinyl and acetate surface species have been investigated by density functional theory calculations. Large clusters have been used to model second-neighbor Pd monomer pair ensembles on PdAu(100) and PdAu(111) surface alloys. Ethylene and acetic acid are weakly bonded to the Pd monomers, while vinyl and acetate are strongly bonded to both Pd and Au atoms being very stable surface species. The ligand effect of the gold atoms surrounding the Pd monomers has been shown to be stronger in the more dense PdAu(111) surface alloy. Cluster model results are in good agreement with experimental evidence providing important insight on the adsorption bonding modes, the assignment of the infrared features, and the preferred adsorption sites. © 2009 American Chemical Society
Il reportage alla maniera di Tiziano Terzani: Buonanotte, Signor Lenin e le epifanie dei luoghi
No full textIn this paper, Gloria Politi embarks upon an analysis of Goodnight, Mister Lenin seen
as an interpretation of the genre of reportage in the peculiar way by its author Tiziano
Terzani. In terms of methodology, this approach draws on theories of literary criticism,
textual hermeneutics and narratology. The analysis shows how the depiction of the flow
of events before the reader’s eyes reveals an inner gaze that, according to Pavel Florensky,
almost creates a figurative mark, just like the impressions conveyed by poetry. Terzani’s
word thus expresses all its evocative potential as a narrative transfer of the rendering of
space in the visual arts
European island landscape and seascape
No full textThe chapter explores several issues related to island biocultural diversity, and in particular to cultural heritage and European island landscapes and seascapes. New concepts and definitions of island landscape and seascape are proposed from previous fundamental studies and current ongoing research on the topic. The aim is to provide a conceptual background to the miscellanea of topics covered in the book Island Landscapes edited by the author
The influence of surface oxygen and hydroxyl groups on the dehydrogenation of ethylene on PdAu surface alloys. A theoretical cluster model study
No full textThe dehydrogenation of ethylene on Pd second-neighbor ensembles of both PdAu(1 0 0) and PdAu(1 1 1) surface alloys in presence of surface oxygen atoms (Os) and hydroxyl groups (OHs) was investigated at the density functional level with a cluster model approach. The calculated activation barriers for ethylene dehydrogenation to form vinyl on Os-and OHs-covered PdAu surfaces are significantly lower than those on clean surface alloys. Therefore, our outcomes suggest that a Langmuir-Hinshelwood-type mechanism involving a vinyl surface species cannot be excluded a priori when investigating the microscopic behaviour of the oxygen-assisted acetoxylation of ethylene on PdAu catalysts. © 2010 Elsevier B.V. All rights reserved
Lu Xun's Revolution : Writing in a Time of Violence /
No full textRecognized as modern China’s preeminent man of letters, Lu Xun (1881–1936) is revered as the nation’s conscience, a writer comparable to Shakespeare or Tolstoy. Gloria Davies’s vivid portrait gives readers a better sense of this influential author by situating the man Mao Zedong hailed as "the sage of modern China" in his turbulent time and place.Widely recognized as modern China’s preeminent man of letters, Lu Xun (1881–1936) is revered as the voice of a nation’s conscience, a writer comparable to Shakespeare and Tolstoy in stature and influence. Gloria Davies’s portrait now gives readers a better sense of this influential author by situating the man Mao Zedong hailed as "the sage of modern China" in his turbulent time and place. In Davies’s vivid rendering, we encounter a writer passionately engaged with the heady arguments and intrigues of a country on the eve of revolution. She traces political tensions in Lu Xun’s works which reflect the larger conflict in modern Chinese thought between egalitarian and authoritarian impulses. During the last phase of Lu Xun’s career, the so-called "years on the left," we see how fiercely he defended a literature in which the people would speak for themselves, and we come to understand why Lu Xun continues to inspire the debates shaping China today. Although Lu Xun was never a Communist, his legacy was fully enlisted to support the Party in the decades following his death. Far from the apologist of political violence portrayed by Maoist interpreters, however, Lu Xun emerges here as an energetic opponent of despotism, a humanist for whom empathy, not ideological zeal, was the key to achieving revolutionary ends. Limned with precision and insight, Lu Xun’s Revolution is a major contribution to the ongoing reappraisal of this foundational figure.Recognized as modern China’s preeminent man of letters, Lu Xun (1881–1936) is revered as the nation’s conscience, a writer comparable to Shakespeare or Tolstoy. Gloria Davies’s vivid portrait gives readers a better sense of this influential author by situating the man Mao Zedong hailed as "the sage of modern China" in his turbulent time and place.Widely recognized as modern China’s preeminent man of letters, Lu Xun (1881–1936) is revered as the voice of a nation’s conscience, a writer comparable to Shakespeare and Tolstoy in stature and influence. Gloria Davies’s portrait now gives readers a better sense of this influential author by situating the man Mao Zedong hailed as "the sage of modern China" in his turbulent time and place. In Davies’s vivid rendering, we encounter a writer passionately engaged with the heady arguments and intrigues of a country on the eve of revolution. She traces political tensions in Lu Xun’s works which reflect the larger conflict in modern Chinese thought between egalitarian and authoritarian impulses. During the last phase of Lu Xun’s career, the so-called "years on the left," we see how fiercely he defended a literature in which the people would speak for themselves, and we come to understand why Lu Xun continues to inspire the debates shaping China today. Although Lu Xun was never a Communist, his legacy was fully enlisted to support the Party in the decades following his death. Far from the apologist of political violence portrayed by Maoist interpreters, however, Lu Xun emerges here as an energetic opponent of despotism, a humanist for whom empathy, not ideological zeal, was the key to achieving revolutionary ends. Limned with precision and insight, Lu Xun’s Revolution is a major contribution to the ongoing reappraisal of this foundational figure.Electronic reproduction. :Mode of access: Internet via World Wide Web.DaviesGloria: Gloria Davies is a literary scholar and historian of China at Monash University in Australia. She is also Adjunct Director of the Australian Centre on China in the World at the Australian National University.Description based on online resource; title from PDF title page (publisher’s Web site, viewed May 26, 2011
Gloria
Get PDFabstract: Gloria is a work written for SATB choir and brass quintet that uses the traditional Latin text of the Gloria found in the ordinary of the Mass. The piece is approximately fourteen minutes and explores a variety of textures, colors, and timbres of the brass quintet and choir. The composition uses quartal sonorities mixed with upper tertian structures while avoiding simple triads and stable root position voicings until the most important climactic moments. The Gloria opens with a fanfare presenting the initial rhythmic motive in a call and response between the brass and choir before the irregular meters of the A section enter. The piece develops a variety of sonorities, pitch collections, and timbres before arriving at the first climactic moment on the text "Rex" (King). The music slowly comes to a point of repose with a brass interlude revealing the motives used in the B section. The choir begins the B section a cappella on the text "Dómine Fili unigénite, Jésu Chríste" (Lord Jesus Christ, the only begotten Son). The section features a dialogue between the brass and choir, though the two groups never sound together. The section includes a lyrical soprano duet incorporating dissonant intervals preceding the choir's response on the text requesting the mercy of the Lord. The section comes to a somber, penitential rest ending with the brass quintet response. The piece gradually builds and accelerates to the second climactic moment on the word "Jésu." From there it once again gains momentum toward the return of the A section on the text "Cum Sáncto Spíritu" (With the Holy Spirit). After a climactic "Amen" section, the composition concludes with a return to the material found in the introduction followed by an affirming brass postlude.Dissertation/ThesisM.M. Composition 201
Open destinies : modern American women and the short story cycle
Get PDFThis thesis examines the juncture between the short story cycle form and gender politics. It explores how twentieth-century women from the United States have been using the form to represent and question gender identity. The introduction outlines commentaries on the story cycle and considers definitions of the form. It includes case studies of earlier twentieth-century cycles by American women: cycles such as Mary McCarthy's The Company She Keeps that have been passed over by critics of the form.
Chapter One presents Eudora Welty's The Golden Apples as a cycle paradigm, examining conventions such as the form's metafictional dimension and its preoccupation with communal identity. Chapter Two argues that Grace Paley's scattered Faith narratives set a standard for more dispersed versions of the form. Chapter Three considers how Joyce Carol Oates uses the sequential cycle to represent gender identity as a social construct. Chapters Four and Five examine the macrocosmic cycles of Gloria Naylor and Louise Erdrich and consider changes in their form and gender politics. The final 'composite' chapters explore postmodern versions of the form such as Susan Minot's Monkeys. The prose works of Sandra Cisneros stretch across the story cycle continuum, whilst Toni Morrison's Paradise is universally regarded as a novel. Readings of contemporary cycles by Melissa Bank, Elissa Schappell and Emily Carter demonstrate that American women are re-invigorating the form to facilitate the plural identity of the postmodern heroine
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