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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.
281

The poetry of N.S. Puleng

Tshauke, Maisaya H. 23 September 2014 (has links)
M.A. (African Languages) / The purpose of this study is to analyze the poetry of Puleng. There is no work done on Puleng to date which reveals his thoughts, ideas, memories and creativity. This study will enlighten interested readers especially budding poets and students of literature...
282

A textual and theoretical reframing of Derek Jarman's films in the context of British cinema in the 1970s and 1980s

Davies, William James January 2016 (has links)
The purpose of this work is to present a reframing and repositioning of films made by Derek Jarman via in-depth textual analysis (rarely seen previously) and attention to relevant theoretical connections (such as heritage, pastiche, camp, adaptation). These discussions are anchored to a consistent contextual grounding within the British film industry/culture, which includes consideration of the history and role/s of the BFI, dialogues with debates of national cinema and heritage, an assessment of Channel 4’s impact and influence, and an investigation into the function of British Film Year and its lists of acknowledged films. The first chapter addresses shortcomings and problems of previous framing, and gives an example of my textual analysis and methodology using previously ignored filmic texts Queen is Dead and Paninaro. With the stifling and dominant biographical/auteur approach removed from application (and the label Jarman accounted for as a categorising structure of the text rather than a reference to an external figure), the thesis considers the films as cultural texts which examine representation and heritage. The next three chapters explore Jubilee, The Tempest, and Caravaggio respectively, addressing the films’ uses of history, cultural heritage and style via facets such as temporal layering, punk and camp modalities, pastiche approaches, adaptation, appropriation, and allusion. The thesis opposes arguments that can be reductive, monolithic, and totalising (like auteur, biographical, and heritage frames of analysis), and instead makes central the operations of the specific filmic text. Rather than allowing texts (in terms of content and meaning) to be subsumed into an examination of the life and personality of the director (as has so often been the case with Jarman films), the filmic texts are observed, analysed and discussed via attentiveness to the particular properties of the text (style; representations; framing), and connected to the British cinema context of the period.
283

Synthesis and Reactions of Some N-Nitrosamines

Gunn, Valerie E. (Valerie Elizabeth) 12 1900 (has links)
Nucleophiles react with the α-acetoxy derivative of α-hydroxybenzylbenzylnitrosamine at the carbonyl carbon of the acetoxy moiety followed by fragmentation to the very same intermediates formed by oxidative metabolism. Since α-acetoxybenzylbenzylnitrosamine has been shown to be able to acylate nucleophiles and since the nucleic acids are nucleophiles, then it is possible that this compound may cause mutations by an acylation pathway instead of or in addition to the more common alkylation pathway. The data in Part I of this dissertation should be considered in any further biological investigations of N,N-dialkylnitrosamine induced mutagenesis or carcinogenesis. The study of the synthesis, reactions, mutagenicity, and the possible correlation to compound liposolubility of cyclic N-nitrosamines was also investigated.
284

The application of Ngara's linguistic format in N.F. Mbhele's short stories, "Amayezi Namathunzi"

Malinga, Sizakele Sellina 04 November 2014 (has links)
M.A. (African Languages) / This study looks at the application of Ngara's linguistic format in NF Mbhele's short stories. The other linguists' theories were used to support those of Ngara. In this work we will mainly use "the linguistic features proper", since they are analysable in terms of formal linguistic descriptions. The above will be discussed as follows: Chapter 1 introduces this study, defines some technical terms and gives a short report on an interview with N.F. Mbhele. Chapter 2 discusses the development of the stylistic framework which is the pillar of our analysis. The application of Ngara's linguistic format is discussed in detail in Chapter 3. In chapter 4 we discuss the imaqery, The concluding statement and suggestions for future research directions that could be undertaken, are discussed in Chapter 5.
285

A discussion of B.N. Tseke's poetic art form

Kekana, Molatelo Agnes 23 September 2014 (has links)
M.A. (African Languages) / Poetry is an art form beyond other genres. It is superior because it is tied up with deep feelings. "It is an outflow of powerful feelings". Poetry is by and large, differentiated from prose by a mark of greater specialism. African poetry is twofold; viz. traditional poetry and modern poetry. Traditional poetry is derived from Africa; and modern poetry is developed largely from the west. A brief statement on Northern Sotho poetry was given attention. The abilities of Tseke as a poet were briefly discussed. Tseke's poems were divided according to themes and poetic forms. Russian Formalism as a literary theory was looked into. Imagery as a poetic device was discussed under headings such as: figures of speech, senses used to evoke images and repetition. Tseke's language was discussed to show his ability to coin new words. Structure as a poetic device included headings such as: structure of poems, what brings structural agreement between stanzas and elements which contribute to the achievement of unity in poems.
286

Efektivní metody detekce plagiátů v rozsáhlých dokumentových skladech / Effective methods of plagiarism detectios in large document repositories

Přibil, Jiří January 2009 (has links)
The work focuses on issues of plagiarism detection in large document repositories. Taking into account real situation that needs to be addressed now in the university environment in the Czech Republic and proposes a system that will be able to carry out this analysis in real time and yet be able to capture the widest possible range of plagiarism methods. The main contribution of this work is taking the definition of so-called unordered n-grams - {n}-grams - which can be used just to detect some forms of advanced plagiarism methods. All cited recommendations that relate to the various components of the system to detect plagiarism - preprocessing the document before document insertion into the corpus, the representation of documents in document storage, identification of potential sources of plagiarism to calculate rates of similarity; visualization analysis of plagiarism - are subject to discussion and appropriately quantified. The result is a set of design parameters of the system so that it can in detect plagiarism in the Czech language language quickly, accurately and yet in most forms.
287

Charakterisierung der Wechselwirkung zwischen N-Myc und Aurora-A im MYCN-amplifizierten Neuroblastom / Characterization of the Interaction between N-Myc and Aurora-A in MYCN amplified Neuroblastomas

Dirks, Johannes January 2019 (has links) (PDF)
Im Neuroblastom ist die Amplifikation des MYCN-Gens, eines Mitglieds der MYC-Onkogenfamilie, mit einer ungünstigen Prognose assoziiert. Der von dem Gen kodierte Transkriptionsfaktor N-Myc ist für die Proliferation der MYCN-amplifizierten Neuroblastomzelllinien notwendig und seine Depletion oder Destabilisierung führen zum Proliferationsarrest (Otto et al., 2009). Da N-Myc auf Proteinebene durch die Interaktion mit der mitotischen Kinase Aurora-A stabilisiert wird, bewirkt deren Depletion oder die Hemmung der Interaktion der beiden Proteine mittels spezieller Aurora- A-Inhibitoren (z.B. MLN8054 und MLN8237) ebenso eine Hemmung der Proliferation – in vitro und in vivo (Brockmann et al., 2013). Bisher ist jedoch unklar, über welchen Mechanismus Aurora-A die Stabilisierung von N-Myc erreicht, die Kinaseaktivität spielt hierbei jedoch keine Rolle (Otto et al., 2009). Eine Möglichkeit stellt die Rekrutierung von Usps dar, die das angehängte Ubiquitinsignal so modifizieren, dass die Erkennung und der Abbau des Proteins durch das Proteasom verringert werden. In der vorliegenden Arbeit wurde die Wirkung von Usp7 und Usp11 auf die Stabilität von N-Myc untersucht. Für beide konnte in Immunpräzipitationen die Interaktion mit N-Myc gezeigt werden. Ebenso erhöhten beide Proteasen in Überexpressionsexperimenten die vorhandene Menge an NMyc. Die Depletion von Usp7 mittels shRNAs führte in IMR-32 zu einem Arrest in der G1-Phase und zur Differenzierung der Zellen. Gleichzeitig wurden stark erniedrigte mRNA- und Proteinmengen von N-Myc und Aurora-A nachgewiesen. Es konnte jedoch nicht eindeutig gezeigt werden, ob die beobachteten zellulären Effekte durch eine vermehrte proteasomale Degradation von N-Myc begründet sind oder ob dabei die veränderte Regulation weiterer Zielproteine von Usp7 eine Rolle spielt. Die Depletion von Usp11 mit shRNAs bewirkte eine Abnahme der N-Myc-Mengen auf posttranslationaler Ebene. Somit stellen beide Usps vielversprechende Angriffspunkte einer gezielten Therapie in MYCN-amplifizierten Neuroblastomen dar und sollten deshalb Gegenstand weiterführender Untersuchungen sein. Über welche Proteindomäne in N-Myc die Interaktion mit Aurora-A stattfindet ist nicht bekannt. Eine mögliche Pseudosubstratbindungssequenz in Myc-Box I (Idee Richard Bayliss, University of Leicester) wurde in der vorliegenden Arbeit untersucht. Durch Mutation dieser Sequenz sollte die Bindung von Aurora-A unmöglich gemacht werden. Allerdings wurde die erwartete Abnahme der Stärke der Interaktion von Aurora-A und N-Myc durch die Mutation ebensowenig beobachtet wie eine verringerte Stabilität. Die Regulation der Phosphorylierung von N-Myc im Verlauf des Zellzyklus wurde durch die Mutation beeinträchtigt. Wie diese Veränderung exakt zu begründen ist bedarf weiterer Experimente / Neuroblastomas with an amplification of the MYCN-gene, a member of the MYC-oncogene family, are associated with a poor prognosis. The transcription factor encoded by this gene, N-Myc, is essential for the proliferation of MYCN-amplified neuroblastoma cell lines and its depletion or destabilization leads to an arrest of proliferation (Otto et al., 2009). Since N-Myc is stabilized by the interaction with the mitotic kinase Aurora-A, the depletion of the kinase or the inhibition of the interaction with N-Myc using a special class of Aurora-A inhibitors (e.g. MLN8054 and MLN8237) inhibits proliferation – in vitro and in vivo (Brockmann et al., 2013). Up to date it is not known by which mechanism Aurora-A is able to stabilize N-Myc preventing it from Fbxw7-mediated proteasomal degradation, interestingly the Aurora-A kinase activity is not necessary (Otto et al., 2009). One possible explanation is the recruitment of Usps, which modify the attached ubiquitin signal and therefore reduce the recognition and degradation of the protein by the proteasome. In this thesis the influence of Usp7 and Usp11 on N-Myc stability was studied. For both the interaction with N-Myc was shown in immune precipitations. Furthermore the overexpression of both proteases increased the amount of N-Myc protein in transfection experiments. The depletion of Usp7 via shRNAs caused the arrest of IMR-32 cells in G1-phase and the differentiation of the cells. Simultaneously strongly reduced amounts of N-Myc and Aurora-A mRNA and proteins were observed. However it could not be shown that the observed effects were mediated by an increased proteasomal degradation of N-Myc and not via the changed regulation of other targets of Usp7. The depletion of Usp11 led to a decrease of the N-Myc amounts, whereas mRNA-levels were unaffected. Thus both Usps are promising targets for a targeted therapy of MYCN-amplified neuroblastomas and the underlying mechanism should be the object of further research. Furthermore the N-Myc domain binding to Aurora-A still remains to be idientified. A possible pseudosubstrate binding site in Myc-Box I (idea of Richard Bayliss, University of Leicester) was investigated in this thesis. To inhibit the possible binding of Aurora-A to this site, two lysines in Myc-Box I were mutated to glutamate (KK51EE). Nonetheless neither the expected decrease of the intensity of interaction of N-Myc and Aurora-A was observed nor was a decrease of the stability of N-Myc. The regulation of the phosphorylation of N-Myc during the cell cycle was changed through the mutagenesis however. It must be clarified in further experiments, what the reasons for this change are.
288

Development of Cobalt and Nickel N-Heterocyclic Carbene Complexes for Cross-Coupling Reactions

Lazarus, Michael Evan 10 July 2020 (has links)
Cross-coupling, which relies on the use of transition metals, is among the most utilized chemical means of establishing carbon-carbon or carbon-heteteroatom bonds between appropriately functionalized sp, sp2, or sp3 centres. However, most cross-coupling reactions rely on the use of palladium to synthesize valuable synthetic targets. This is problematic for the chemical industry as palladium is limited in supply and expensive. Chemists have therefore sought to replace palladium with first-row transition metals (e.g., iron, cobalt and nickel) and recent reports on cobalt and nickel catalyzed cross-coupling reactions indicate that these metals can be used in this capacity. Unfortunately, protocols developed (so far) for these metals are unsuitable for the synthesis of targets with base-sensitive functional groups as they involve strongly basic reaction conditions. Research in this thesis aims to develop both cobalt and nickel pre-formed catalysts that will display high catalytic activity in mildly basic reaction conditions. Current methodologies for cobalt and nickel cross-coupling reactions use either phosphine ligands or NHC ligands of moderate steric bulk (IMes or IPr). Recent advancements in the development of Pd-PEPPSI catalysts have demonstrated that both pre-forming the catalyst and using larger NHC ligands (IPent, IPentCl, or IHept) are required for high catalytic activity in weakly basic conditions. Thus, it was hypothesized that the development of pre-formed cobalt and nickel NHC complexes analogous to their Pd counterparts would improve reactivity in Negishi, Suzuki-Miyaura, and Buchwald-Hartwig amination cross-coupling reactions. Co(IPent)Cl2(Pyr), Co(IPentCl)Cl2(Pyr), and Co2IPr2(OAc)4 were prepared, identified by X-ray crystallography, and evaluated in preliminary Negishi cross-coupling reactions. These complexes were found to be ineffective, but Co2IPr2(OAc)4 was found to be effective for Suzuki-Miyaura cross-coupling. A base screen was performed to enable the use of weak bases, however, the reaction only worked by pre-forming the boronate with n-BuLi, rendering the reaction conditions intolerant of base-sensitive functional groups. [Ni(IPr)]2(µ-Cl)2 , Ni(IPr)Cl(allyl), and Ni(IPent)Cl(allyl) complexes were synthesized and evaluated in Buchwald-Hartwig aminations. Several bases were examined for these reactions but only sodium tert-butoxide was found to be effective. The presence of TEMPO and BHT in these transformations proved deleterious suggesting the involvement of radical intermediates. Finally, stoichiometric reactions were performed to isolate intermediates in the catalytic cycle, supporting the formation of nickel(0).
289

Associative Nitrogen-Fixing Bacteria and their Potential to Support the Growth of Bioenergy Grasses on Marginal Lands

Wewalwela, Jayani Jeewanthi 13 December 2014 (has links)
Rising demands for both food and energy have lifted up the idea of producing renewable biofuels from bioenergy grasses that can companion with associative N2ixing bacteria. Associative N2ixing bacteria can partially fulfill the N requirements of bioenergy grasses enabling successful application for marginal lands. The overall objective of this study was to measure the potential N2ixation of bacteria associated with three bioenergy grasses, giant miscanthus (Miscanthus x giganteus), switchgrass (Panicum virgatum; ‘Alamo’) and energycane (hybrid of Saccharum spontaneum and S. officinarum; HO 02-147) as well as identifying N2ixing bacteria associated with these energy grasses and applying these isolates to grasses to increase biomass yield. It was hypothesized that three different energy grasses, giant miscanthus, switchgrass, and energycane have different capabilities to support the growth of associative N2ixing bacteria, and thus exhibit different rate and quantities of N2ixation. The dynamics of delta15Nair in the root-zones of three perennial bioenergy grasses, biomass yield and nitrogen derived from (%Ndfa) were obtained. Greater potential for N2ixation was identified in energycane associated plant system compared to switchgrass and giant miscanthus. Sorghum bicolor (M81-E) was used to calculate the %Ndfa. Moreover, a 15N2 enriched greenhouse study was carried out to estimate and compare the contribution of ANF to support field data. Greenhouse data further confirmed that energycane associated bacteria has greater potential N2ixation compared to giant miscanthus and switchgrass. Composition and diversity of N2ixing bacteria associated as endophytes and in the rhizosphere community of these three energy grasses were identified in marginal lands. Diverse N2ixing bacteria were observed to be associated with different grasses and Azospirillum sp. was identified in energycane. The effect of N2ixing bacteria on biomass was studied by inoculating three energy grasses with the bacteria isolated from energycane. Increased root lengths of giant miscanthus were observed upon inoculation. However, no other changes in biomass yield or shoot lengths were observed in three bioenergy grasses. Further research is needed to quantify endophytic and rhizosphere N2ixing bacteria and to determine their role in association in an effort to increase the biomass yield of other grasses and reduce N fertilizer inputs.
290

Equilibria in nonaqueous solutions of tetra-n-butylammonium salts.

Abbruzzese, Elvio January 1970 (has links)
No description available.

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