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Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Evaluating the neuroprotective effect of curcumin on a PINK1 cell model of Parkinson's disease
Get PDFThesis (MSc)--University of Stellenbosch University, 2022.ENGLISH ABSTRACT: Parkinson’s disease (PD) is a neurodegenerative disorder characterized by a loss of neurons producing
the neurotransmitter dopamine. Notably, despite extensive studies that have revealed numerous
dysregulated processes associated with PD, fundamental gaps still exist in our knowledge of the
disease pathophysiology. Our understanding of the disease includes processes such as mitochondrial
dysfunction causing increased oxidative stress and energy failure, as well as misfolded protein
accumulation in large inclusions. However, the spatiotemporal sequence of events leading to PD and,
importantly, the initial factors that trigger disease onset remain elusive. This challenges the
development of effective therapeutic strategies to prevent and cure PD. Moreover, the various side
effects associated with conventional pharmaceuticals currently used to treat this disease motivate the
search for a natural treatment that can avoid augmenting the suffering associated with an already
debilitating disease. It is evident that mitochondrial dysfunction and oxidative stress are likely to be
involved in the disease pathogenesis, therefore studying these phenomena in PD may lead to the
development of more effective therapeutic strategies.
Curcumin is a plant-based polyphenol that has been observed to have antioxidant properties, increase
cell viability, and enhance mitochondrial function. Consequently, the aim of the present study was to
create a PD cellular model and evaluate the potential protective effects of curcumin. Therefore, we
sought to establish an appropriate PD model by transfecting SH-SY5Y cells with wild-type (WT) or
G309D mutant PINK1 cDNA, of which the latter has been shown to upregulate dopamine and lead to
cytotoxicity. Additionally, since several neurotoxins have been shown to trigger PD, the toxic
herbicide paraquat was administered to complement the model with cellular damage and
mitochondrial dysfunction. To confirm the model, we performed RT-qPCR to measure gene
expression levels of PINK1 and tyrosine hydroxylase (TH), an enzyme in the dopamine synthesis
pathway. PINK1 was significantly upregulated in the mutant, however, no significant difference in TH
gene expression was observed between groups. We then sought to measure the levels of dopamine in
transfected cells using liquid chromatography-mass spectrometry (LC-MS). Although no dopamine
was detected using LC-MS, higher levels of phenylalanine, a precursor of dopamine, were observed in
the mutant. Using this model, we sought to test the protective effects of curcumin using assays that
measure cellular and mitochondrial health. A toxic paraquat concentration of 1.7 mM was chosen to
elicit a 50 % decrease in cell viability for the model, while a curcumin concentration of 2.5 μM was
chosen as it exhibited no toxic effects.
Following the establishment of the model, four treatment groups were established for all experiments
thereon: untreated control, curcumin only treatment, paraquat only treatment, and pre-treatment
(curcumin treatment followed by paraquat treatment). We found that curcumin was unable to
significantly rescue the paraquat-induced reduction in cell viability and mitochondrial membrane potential. The latter was significantly reduced in PINK1 transfected groups, more so in the G309D
mutant, indicating the toxic effects of the mutation. Thereafter, the effects of curcumin and
polycaprolactone encapsulated nanocurcumin on cell viability were compared. Formulations of
curcumin including nanocurcumin are postulated to improve the stability and efficacy of curcumin.
Interestingly, curcumin had a greater protective effect, whereas nanocurcumin as well as the empty
nanoparticles elicited toxicity. In fact, p re-treatment with the nanocurcumin prior to paraquat
treatment caused a 30 % greater loss in cell viability compared to the paraquat treatment alone.
Finally, a literature review was published, exploring the potential of consistent dietary consumption of
curcumin as an alternative or supplement to existing therapies. We speculate that curcumin binds to α-
synuclein protein (found to accumulate in PD) and that this complex is subsequently excreted from
the body via the large intestine. In this view, replacing some of the PD drugs in an individual’s
treatment regime with a nutraceutical, or ‘functional food’, like curcumin may improve therapeutic
benefits with fewer side effects. Considering these results and the published evidence for curcumin as
a dietary ‘nutraceutical’, further studies are required to optimize curcumin treatment before
advocation of its widespread use as a PD therapeutic agent. Study limitations include the use of an
unverified WT plasmid and an undifferentiated cell line, which can be addressed in future work. The
findings in this study are of importance as they may contribute to advancing the development of novel
plant-based therapies to treat and potentially prevent this detrimental disease.AFRIKAANSE OPSOMMING: Parkinson se siekte (PS) is 'n neurodegeneratiewe versteuring wat gekenmerk word deur 'n verlies aan
neurone wat die neurotransmitter dopamien produseer. Merkwaardig, ten spyte van omrykende
studies wat talle gedisreguleerde prosesse verwant aan PS geopenbaar het, bestaan fundamentele
gapings steeds in ons kennis van die siektepatofisiologie. Ons begrip van die siekte sluit prosesse soos
mitochondriale disfunksie in wat verhoogde oksidatiewe stres en energiemislukking veroorsaak,
asook verkeerde proteïenophoping in groot insluitings. Die tydruimtelike volgorde van gebeure wat
tot PS lei en, belangriker, die aanvanklike faktore wat siekte-aanvang veroorsaak, bly egter
ontwykend. Dit daag die ontwikkeling van effektiewe terapeutiese strategieë uit om PS te voorkom en
te genees. Bowendien, het die huidige konvensionele farmaseutiese behandelinge vir PS tale newe-
effekte. Dit dien as motivering vir soektogte na ‘n natuurlike behandeling wat die aanvullende leiding
kan verminder van ‘n reeds afbrekende siekte. Dit is duidelik dat mitochondriale disfunksie en
oksidatiewe stres betrokke is by die siekte se patologie, daarom kan die bestudering van hierdie
verskynsels in PS lei tot die ontwikkeling van meer effektiewe terapeutiese strategieë.
Kurkumien is 'n plantgebaseerde polifenol wat waargeneem is om antioksidant eienskappe te toon,
verhoog sel lewenskragtigheid en verbeter mitochondriale funksie. Gevolglik was die doel van die
huidige studie om 'n PS-sellulêre model te skep en die potensiële beskermende effekte van kurkumien
te evalueer. Daarom het ons probeer om 'n toepaslike PS-model te vestig deur SH-SY5Y-selle met
wilde-tipe (WT) of G309D muteerde PINK1 cDNA te transreguleer, waarvan laasgenoemde
dopamien op gereguleer het wat gelei het tot sitotoksiteit. Daarbenewens, aangesien verskeie
neurotoksiene getoon is om PS te aktiveer, is die giftige onkruiddoder, parakwat, toegedien om die
model aan te vul met sellulêre skade en mitochondriale disfunksie. Om die model te bevestig, het ons
RT-qPCR uitgevoer om geen-uitdrukkingsvlakke van PINK1 en tyrosine hydroxylase (TH), 'n ensiem
betrokke by die chemiese samestelling van dopamien, kwantitatief te meet. PINK1 was aansienlik
opgereguleer in die muteerde, maar geen beduidende verskil was opgemerk in TH-geenuitdrukking
tussen groepe nie. Ons het toe probeer om die vlakke van dopamien in transfekte selle te meet met
behulp van vloeibare chromatografie-massaspektrometrie (VC-MS). Alhoewel geen dopamien
opgespoor was met behulp van VC-MS nie, was hoër vlakke van fenylalanien, 'n voorloper van
dopamien, in die muteerde waargeneem. Met behulp van hierdie model het ons probeer om die
beskermende effekte van kurkumien te toets met behulp van eksperimente wat sellulêre en
mitochondriale gesondheid kan bepaal. 'n Giftige parakwat konsentrasie van 1.7 mM was gekies om 'n
50% afname in sel lewensvatbaarheid in die model te ontlok, terwyl 'n kurkumien konsentrasie van
2.5 μM gekies was, aangesien dit geen giftige effekte getoon het nie.
Na die bevestiging van die model was vier behandelingsgroepe gestig vir alle eksperimente wat volg
daarna, dit sluit in: onbehandelde kontrole, kurkumien alleenlik, parakwat alleenlik, en voor-behandeling (kurkumien behandeling gevolg deur parakwat behandeling). Ons het gevind dat
kurkumien nie merkwaardig die selle kon beskerm teen die verlaagde sel lewenskragtigheid en
mitochondirale membraanpotentiaal wat geïnduseer was deur parakwat nie. Die mitochondriale
membraanpotentiaal was aansienlik verminder in die PINK1-getransfekteerde groepe, meer so as in
die G309D-muteerde, dit dui die giftige effekte van die mutasie aan. Daarna is die effek van
kurkumien en policaprolactone ingeslote nanokurkumien op sel lewensvatbaarheid vergelyk.
Formulerings van kurkumien, insluitend nanokurcumin, word gepostuleer om die stabiliteit en
doeltreffendheid van kurkumien te verbeter. Interessant genoeg, kurkumien het 'n groter beskermende
effek gehad, terwyl nanokurcumin sowel as die leë nanopartikels toksisiteit getoon het. In
werklikheid, het die voorbehandeling met nanokurkumien (voor parakwat behandeling) ‘n 30% groter
verlies in sel lewenskragtigheid veroorsaak as die selle met slegs parakwat behandeling. Ten slotte is
'n literatuuroorsig gepubliseer, wat die potensiaal van konsekwente dieet verbruik van kurkumien
ondersoek as 'n alternatief of aanvulling tot bestaande terapieë. Ons spekuleer dat kurkumien aan α-
sinukleien proteien bind (gevind om te versamel in PS) en dat hierdie kompleks daarna uit die
liggaam uitgeskei word deur die dikderm. Deur dit in ag te neem, kan die vervanging van sommige
van die huidige PS-behandelinge met nutraceutiese produkte, of ‘funksionele kos’, soos kurkumien,
voordelig wees en minder newe-effekte hê. Samevattend met hierdie resultate en die gepubliseerde
bewyse vir kurkumien as ‘n dieet ‘nutraceutical’, is verdere studies nodig om kurkumien behandeling
te optimiseer voordat die wydverspreide gebruik daarvan as 'n PS terapeutiese middel kan gebeur.
Studie beperkings sluit in die gebruik van 'n ongeverifieerde WT-plasmied en 'n ongedifferensieerde
sellyn, wat in toekomstige werk aangespreek kan word. Die bevindings in hierdie studie is van belang,
aangesien dit kan bydra tot die bevordering van die ontwikkeling van nuwe plantgebaseerde terapieë
om hierdie nadelige siekte te behandel en moontlik te voorkom
Variations on the Author
Get PDF“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
Get PDFWe 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
Get PDFWe 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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
Author Under Sail The Imagination of Jack London, 1893-1902
No full textIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Intro -- Title Page -- Copyright Page -- Dedication -- Contents -- Acknowledgments -- Introduction -- 1. Spirit Truth -- 2. From Absorption to Theatricality and Back Again -- 3. "I Will Build a New Present" -- 4. Sons as Authors -- 5. Fathers as Publishers -- 6. The Daughter as Author -- 7. Lovers as Authors -- 8. At Sea with the Family -- 9. Yellow News, Yellow Stories -- 10. The Return Home -- Notes -- Bibliography -- Index -- About Jay WilliamsIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Description based on publisher supplied metadata and other sources.Electronic reproduction. Ann Arbor, Michigan : ProQuest Ebook Central, YYYY. Available via World Wide Web. Access may be limited to ProQuest Ebook Central affiliated libraries
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