1,721,351 research outputs found
Structural and functional studies on 6-methylsalicylic acid synthase from Penicillium patulum and holo-acy1 carrier protein synthase from Escherichia coli
No full textThe type I polyketide synthase, 6-methylsalicylic acid synthase, is a multifunctional enzyme that catalyses the formation of 6-methylsalicylic acid from one starter unit of acetyl-CoA, three extender units of malonyl-CoA and one equivalent of the reducing cofactor NADPH. In the absence of NADPH, a triketide intermediate is released from the enzyme as triacetic acid lactone.Using succinyl-CoA transferase, purified from porcine heart, [2-13C]-malonyl-CoA was biosynthesised and in a linked assay, [13C]-labelled 6-methylsalicylci acid and [13C]-labelled triacetic acid lactone were produced in the absence of externally added acetyl-CoA. By collision induced dissociation mass spectrometric analysis, it was determined that 6-methylsalicylic acid synthase possesses a malonyl-CoA decarboxylase activity. Similar methodology was also used to show that in the absence of NADPH, 6-methylsalicyclic acid synthase is able to synthesise small amounts of orsellinic acid as well as triacetic acid lactone. It is proposed that in the absence of NADPH, the triketide intermediate is a poor substrate for the β-ketosynthase but that 1-2% can react with malonyl-CoA to give orsellinic acid.Fluoroacetyl-CoA, chloroacetyl-CoA, and bromoacetyl-CoA were synthesised and purified and their effect/action with 6-methylsalicylic acid synthase was investigated. All were shown to inactivate the enzyme although none were incorporated into halo-products. The interaction between 6-methylsalicylic acid synthase and several N-acetylcysteamine intermediates was also investigated. The enzyme appears to prefer to synthesise its own intermediates rather than accept externally added substrate analogues.</p
Introduction:demystifying the PhD by publication
No full textThis chapter documents the rationale for compiling a collection on the PhD by Publication. The aim of the book is to “demystify” this alternative route of doctoral education because there is a dearth of publications (journal articles or books) on this PhD route which is gaining popularity around the world. This book attempts to “demystify” PhD by Publication by identifying pertinent issues and (mis)conceptions pertaining to policies and practices through research, research syntheses, and surveys of university policies on the PhD by Publication internationally (Part I – Landscapes of PhD by Publication). Another layer of “demystification” pertains to experience (Part II: Narratives of PhD by Publication). The inclusion of reflective and autobiographical accounts by PhD by Publication supervisors, students, and graduates internationally provides a vivid insider’s perspective toward this PhD route. This chapter closes with an outline of each chapter of the book
Conclusions:demystifying the PhD by publication and the research road ahead
No full textThis concluding chapter draws together some of the emergent themes from the papers presented within this collection on the PhD by Publication, and does so by first of all providing a socio-historical context for the recent interest in this qualification route. We describe developments in academic culture and suggest that the PhD by Publication is one small part of much broader changes in how the academy functions within contemporary society. Two clear and interrelated themes are then developed and suggested for further research. Firstly, work on the development processes and linguistic characteristics of a developing genre are signposted. Relatedly, the way that academic identities are negotiated and motivated within the expanding vision of what it is to be an academic is suggested as an important area for further examination
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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