853 resultados para transformations of VFAs
Resumo:
In the global knowledge economy, knowledge-intensive industries and knowledge workers are extensively seen as the primary factors to improve the welfare and competitiveness of cities. To attract and retain such industries and workers, cities produce knowledge-based urban development strategies, and therefore such strategising has become an important development mechanism for cities and their economies. The paper discusses the critical connections between knowledge city foundations and integrated knowledge-based urban development mechanisms in both the local and regional level. In particular, the paper investigates Brisbane’s knowledge-based urban development strategies that support gentrification, attraction, and retention of investment and talent. Furthermore, the paper develops a knowledge-based urban development assessment framework to provide a clearer understanding of the local and regional policy frameworks, and relevant applications of Brisbane’s knowledge-based urban development experience, in becoming a prosperous knowledge city. The paper, with its knowledge-based urban development assessment framework, scrutinises Brisbane’s four development domains in detail: economy; society; institutional; built and natural environments. As part of the discussion of the case study findings, the paper describes the global orientation of Brisbane within the frame of regional and local level knowledge-based urban development strategies performing well. Although several good practices from Brisbane have already been internationally acknowledged, the research reveals that Brisbane is still in the early stages of its knowledge-based urban development implementation. Consequently, the development of a monitoring system for all knowledge-based urban development at all levels is highly crucial in accurately measuring the success and failure of specific knowledge-based urban development policies, and Brisbane’s progress towards a knowledge city transformation.
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We obtain the superconformal transformation laws for theN=2,D=4 SSYM. The transformations involve Yang-Mills fields and the corresponding field strength tensor is not constrained to be self antidual. We explicitly demonstrate the closure of the superconformal algebra.
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Microbial degradation of geraniol, citronellol, linalool and their corresponding acetates, structurally modified linalool and linalyl acetate, α-terpineol and β-myrcene are presented. Oxygenative and prototropic rearrangements are normally observed during the microbial metabolism of monoterpenes. Three types of oxygenation reactions are observed, namely, (a) allylic oxygenation (b) oxygenation on a double bond and (c) addition of water across the double bond. The studies indicate commonality in the reaction types or processes occurring during the metabolism of various related monoterpenes and also establish the convergence of degradative pathways at a central catabolic intermediate.
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We study integral representations of Gaussian processes with a pre-specified law in terms of other Gaussian processes. The dissertation consists of an introduction and of four research articles. In the introduction, we provide an overview about Volterra Gaussian processes in general, and fractional Brownian motion in particular. In the first article, we derive a finite interval integral transformation, which changes fractional Brownian motion with a given Hurst index into fractional Brownian motion with an other Hurst index. Based on this transformation, we construct a prelimit which formally converges to an analogous, infinite interval integral transformation. In the second article, we prove this convergence rigorously and show that the infinite interval transformation is a direct consequence of the finite interval transformation. In the third article, we consider general Volterra Gaussian processes. We derive measure-preserving transformations of these processes and their inherently related bridges. Also, as a related result, we obtain a Fourier-Laguerre series expansion for the first Wiener chaos of a Gaussian martingale. In the fourth article, we derive a class of ergodic transformations of self-similar Volterra Gaussian processes.
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This dissertation traces a set of historical transformations the Darwinian evolutionary narrative has undergone toward the end of the twentieth century, especially as reflected in Anglo-American popular science books and novels. The study has three objectives. First, it seeks to understand the organizing logic of evolutionary narratives and the role that assumptions about gender and sexuality play in that logic. Second, it asks what kinds of cultural anxieties evolutionary theory raises and how evolutionary narratives negotiate them. Third, it examines the possibilities and limits of narrative transformation both as a historical phenomenon and as a theoretical question. This interdisciplinary dissertation is situated at the intersection of science studies, cultural studies, literary studies, and gender studies. Its understanding of science as a cultural practice that both emerges from and contributes to cultural expectations and institutional structures follows the tradition of science studies. Its focus on the question of popular appeal and the mechanisms of cultural change arises from cultural studies. Its view of narrative as a structural phenomenon is grounded in literary studies in general and feminist narrative theory in particular. Its understanding of gender and sexuality as implicated in discourses of epistemic authority builds on the view of gender and sexuality as contingent cultural categories central to gender studies. The primary material consists of over 25 British and American popular science books and novels, published roughly between 1990 and 2005. In order to highlight historical transformations, these texts are read in the context of Darwin s The Origin of Species and The Descent of Man, on the one hand, and such sociobiological classics as E. O. Wilson s On Human Nature and Richard Dawkins s The Selfish Gene, on the other. The research method combines feminist narrative analysis with cultural and historical contextualization, emphasizing discursive abruptions, recurrent narrative patterns, and underlying continuities. The dissertation demonstrates that the relationship between Darwin s evolutionary narrative and late twentieth-century evolutionary narratives is characterized by reemphasis, omissions, and continuous rewriting. In particular, contemporary evolutionary discourse extends the role assigned to reproduction both sexual and narrative in Darwin s writing, generating a narrative logic that imagines the desire to reproduce as the driving force of evolution and posits the reproductive sex act as the endlessly repeated narrative event that keeps the story going. The study argues that the popular appeal of evolutionary accounts of gender, sexuality, and human nature may arise, to an extent, from this reproductive narrative dynamic. This narrative dynamic, however, is not logically invulnerable. Since the continuation of the evolutionary narrative relies on successful reproduction, the possibility of reproductive failure poses a constant risk to narrative futurity, arousing cultural anxieties that evolutionary narratives need to address. The study argues that evolutionary narratives appease such anxieties by evoking a range of cultural narratives, especially romantic, religious, and national narratives. Furthermore, the study shows that the event-based logic of evolutionary narratives privileges observable acts over emotions, pleasures, identities, and desires, thus engendering a set of conceptual exclusions that limits the imaginative scope of evolution as a cultural narrative.
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We obtain the superconformal transformation laws of theN=4 supersymmetric Yang-Mills theory and explicitly demonstrate the closure of the algebra.
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Incubation of acetates of geraniol, citronellol and linalool with Aspergillus niger resulted in their hydrolysis to corresponding alcohols which were further hydroxylated to their respective 8-hydroxy derivatives. In the case of linalyl acetate, besides linalool and 8-hydroxylinalool, small amounts of geraniol and agr-terpineol were also formed. Microsomes (105 000xg sediment) prepared from induced cells of A. niger were found to convert (1-3H)citronellol to 8-hydroxy citronellol in the presence of NADPH and O2. The pH optimum for the hydroxylase was found to be 7.6.
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Bioconversion of acyclic isoprenoids using a strain of Aspergillus niger results in hydroxylated metabolites with regio- and stereoselectivity. The organism carries out oxidation of the terminal allylic methyl group and the remote double bond in all the compounds tested (I-VII). However, these two activities seem to have preferential structural requirements. When an acyclic isoprenoid with a ketone functionality such as geranylacetone is used as the substrate, the organism also carries out the asymmetric reduction of the keto group. All the metabolites formed have been purified and characterized by conventional spectroscopic methods and quantification has been made by gas chromatographic analyses.
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A versatile fungus isolated in our laboratory and identified as Mucor piriformis has been shown to effect novel and preparatively useful transformations in steroids and morphine alkaloids. The organism very effectively carries out hydroxylation of various C-19 and C-21 steroids at 7 and 14-positions. Although the organism is capable of catalysing hydroxylation at 6 beta and 11 alpha-positions, these are not the major activities. The 14 alpha-hydroxylase appears to have a broad substrate specificity. However, steroids with a bulky substitution at C-17 alpha-position or without the 4-en-3-one group are not accepted as substrates by the 14 alpha-hydroxylase system. Studies have demonstrated how various C-19 and C-21 steroids can be modified to yield new structures which are either difficult to prepare by traditional methods or hitherto unknown. The organism also very efficiently and selectively carries out the N-dealkylation of thebaine and its N-variants. Interestingly, the nor-compound formed does not get further metabolized. Since thebaine is very often used as a starting material to synthesize various morphine agonists as well as antagonists, and one of the steps involved in their preparation is the N-dealkylation reaction, the microbial process could certainly offer an alternative approach.
Resumo:
A bacterial strain belonging to the genus Bacillus isolated by enrichment culture technique using morphine as a sole source of carbon transforms morphine and codeine into 14-hydroxymorphinone and 14-hydroxycodeinone as major and 14-hydroxymorphine and 14-hydroxycodeine as minor metabolites, respectively. When the N-methyl group in morphine and codeine are replaced by higher alkyl groups, the organism still retains its ability to carry out 14-hydroxylation as well as oxidation of the C-6-hydroxyl group in these N-variants, although the level of metabolites formed are considerably low. The organism readily transforms dihydromorphine and dihydrocodeine into only dihydromorphinone and dihydrocodeinone, respectively; suggesting that the 7,8-double bond is a necessary structural feature to carry out 14-hydroxylation reaction. The cell free extract (20,000 x g supernatant), prepared from morphine grown cells, transforms morphine into 14-hydroxymorphinone in the presence of NAD(+), but fails to show activity against testosterone. However, the cell free extract prepared from testosterone grown cells contains significant levels of 17 beta- hydroxysteroid dehydrogenase but shows no activity against morphine.