1,720,957 research outputs found
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
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
Cyclodextrins as enabling excipients in ophthalmic drug delivery
Full text linkSýklódextrín eru hjálparefni sem notuð eru lyfjaform svo sem vatnslausnir (t.d.
stungulyf) og föst lyfjaform (t.d. töflur), til að auka leysanleika, stöðugleika og
aðgengi lyfjanna. Í þessu verkefni var notkun sýklódextrína sem hjálparefni í
augndropum rannsökuð. Rannsakað var hvernig sýklódextrín hafa áhrif á
eðlisefnafræðilega eiginleika (þ.e. leysanleika og stöðugleika) lyfja og hvernig
þau auka frásog lyfja í gegnum lífrænar himnur. Einnig voru rannsökuð áhrif
sýklódextrína á frumur augans, svo sem áhrif þeirra á sjónhimnu augans.
Aðgengi lyfs sem gefið er á yfirborð augans er oftast aðeins 3 til 5%, það
er aðeins 3 til 5% af lyfinu frásogast inn í augað. Helstu ástæður lélegs
aðgengis augnlyfja frá yfirborði augans er takmarkað frásog þeirra í gegnum
lífrænar himnur, svo sem í gegnum hornhimnuna. Flest lyf eru einnig fitusækin
og hafa því mörg hver takmarkaðan leysanleika í vatni. Þau leysast illa upp í
augndropum, sem oftast eru vatnslausnir lyfja, og tárahimnunni sem hylur
yfirborð augans. Önnur stór áskorun er efnafræðilegur óstöðugleiki margra
lyfja í vatnslausnum sem takmarkar geymsluþol augndropa. Hægt að nota
sýklódextrín til að auga bæði stöðugleika og leysni lyfja. Í vatnslausnum
mynda sýklódextrín fléttur (þ.e. komplexa) með fitusæknum lyfjum.
Fitusæknar sameindir, eða fitusæknir hlutar sameindanna, setjast í op í miðju
sýklódextrínsameindanna sem þá verja lyfin fyrir utanaðkomandi áhrifum í
lausninni. Sýklódextrín geta einnig aukið aðgengi lyfjanna að lífrænum
himnum og þar með aðgengi þeirra inn í augað. Að lokum hafa nýlegar
rannsóknir sýnt að sýklódextrín geta myndað fléttur með ýmsum lífrænum
efnasamböndum eins og kólesteróli. Því er ekki ósennilegt að hægt verði að
nota sýklódextrín við meðhöndlun á sjónhimnusjúkdómum, eins og Stargardtsjúkdómi og slagæðastíflu í sjónhimnu. Rannsóknir á eiturverkunum
sýklódextrína á sjónhimnu eru þó takmarkaðar.
Áhrif ýmissa sýklódextrína á leysanleika og stöðugleika takrólímus og
díflúprednats í vatni voru rannsökuð. Áhrifum sýrustigs (pH), sýklódextrína og
fjölliða á niðurbrotsferla og niðurbrotshraða lyfjanna voru rannsökuð með
vökvagreini (HPLC) og massagreini (MS). Myndun flétta lyfja og sýklódextrín
var könnuð með ýmsum aðferðum svo sem NMR, DSC og FTIR. Áhrif
sýklódextrína á flæði lyfja í gegnum himnur voru rannsökuð. Að lokum voru
áhrif 2-hýdroxýprópýl-ȕ-sýklódextríns +3ȕ&' RJ PHWêO-ȕ-sýklódextríns
50ȕ&' á frumur sjónhimna úr músum rannsökuð.
Rannsóknir á niðurbrotshraða sýndu að takrólímus hefur hámarks
stöðugleika í vatnslausn við pH á milli 4 og 6, á meðan díflúprednat er
stöðugast við pH um 5. Niðurbrotið beggja lyfjanna eykst verulega ef pH-ið fer
yfir 6. MS rannsóknir sýndu að vatnsrof var aðalorsök niðurbrots takrólímus í
+3ȕ&'YDWQVODXVQXP Leysanleikarannsóknir sýndu Dèȕ-VêNOyGH[WUtQ ȕ&'
og afleiður þess mynda vatnsleysanlegar fléttur með takrólímusi og eru bestu
sýklódextrínin til að auka leysanleika lyfsins í vatni, en Ȗ-sýklódextrín (Ȗ&') og
afleiður þess voru bestar fyrir díflúprednat. Ennfremur sýndu
stöðugleikarannsóknir með sýklódextrínum og mismunandi fjölliðum að
stöðugleiki takrólímus í vatni jókst með blöndu +3ȕ&' RJ W\OR[DSóli.
Rannsóknir á díflúprednati gáfu svipaðar niðurstöður þar sem blanda af 2-
hýdroxýprópýl-Ȗ-sýklódextríni (+3Ȗ&') og póloxamer 407 reyndist best. Þá
voru einkenni flétta díflúprednats og +3Ȗ&' rannsökuð á bæði föstu formi og
í lausn, það er díflúprednat +3Ȗ&' fléttu og díflúprednat/HPȖ&' Sóloxamer
fléttu. NanoSight var notað til að mæla myndun díflúprednat +3Ȗ&'
nanóagna og díflúprednat +3Ȗ&' Sóloxamer nanóagna, stærð þeirra og
stærðardreifingu sem hlutfall af styrk póloxamers. Niðurstöðurnar voru síðan
staðfestar með rafeindasmásjárrannsóknum (TEM). Eiginleikar fléttanna á
föstu formi voru rannsakaðar með DSC og FTIR. Rannsóknir á flæði
hýdrókortisóns í gegnum himnur sýndu að styrkur mismunandi leysanleika
aukandi efna (þ.e. +3ȕ&' HWDQyOs og natríumlárýlsúlfats) hafði markverð áhrif
á flæði hýdrókortisóns í gegnum himnur. Áhrifin voru tengd varmafræðilegu
ástandi lyfsins í vatnslausninni. Rannsóknir á eituráhrifum VêQGXDè50ȕ&'
hafði meiri eituráhrif en +3ȕ&' VHPVMyQKLPQDQþoldi í allt að 10 mM +3ȕ&'
styrk. Auk þess sýndu rannsóknir sem gerðar voru á flúrljómandi afleiðum
sömu sýklódextrína að bæði 50ȕ&' og +3ȕ&' JHWD IDULè GM~SW LQQ t
sjónhimnuna.
Þótt Dè+3ȕ&'KDILreynst besta sýklódextrínið fyrir takrólímus og aukið
bæði leysanleika þess og stöðugleika, var aukningin ekki nægjanleg til að hægt
væri að mynda takrólímus augndropa. Leysaleiki díflúprednats í vatnslausnum
sem innihéldu +3Ȗ&' nægði til að mynda augndropa sem innihalda 0,1%
díflúprednat, sem er tvöfalt meira magn en í þeim díflúprednat augndropum
sem nú eru á markaði. Frekari rannsóknir þarf þó að gera til að fullhanna
augndropanaCyclodextrins (CDs) have been widely used as pharmaceutical excipients for
formulation purposes for different drug delivery systems. Recent developments
have explored their use in ophthalmic drug delivery to overcome the challenges
faced due to the anatomical and physiological barriers of the eye. Other big
challenges in the ocular delivery are the poor aqueous solubility and chemical
instability of many drugs in aqueous solutions and the short retention time. As
we know, CDs can be used to improve the stability and solubility of hydrophobic
drugs in aqueous CD solutions through the formation of drug/CD complexes.
The lipophilic molecules of parts of larger drugs can enter the CD cavity and
hence can be protected from external factors in the solution. Not only this but
the use of CDs as solubilisers has helped in the permeation properties of
different hydrophobic drugs. In addition to this, recent studies have shown that
CDs are able to form complexes with a variety of biomolecules, such as
cholesterol. This has subsequently paved the way for the possibility of using
CDs in retinal diseases, such as Stargardt disease and retinal artery occlusion,
where CDs could absorb cholesterol pumps, but the studies on the retinal
toxicity of CDs are limited.
This study aimed to explore the applicability of CDs in ophthalmic delivery
as solubilisers/stabilisers for various hydrophobic drugs (tacrolimus and
difluprednate) to develop a vehicle for aqueous eye drops, their concentration
effect on important parameters for formulation like permeation, and to examine
the retinal toxicity of different CDs and their localisation within retinal tissues.
Phase-solubility and kinetics studies were performed in the presence of
different CDs at different pH values for tacrolimus and difluprednate. A mass
spectrometric (MS) study was also done to elucidate the degradation
mechanism of the tacrolimus in an aqueous CD solution. Furthermore,
stabilisation studies were done with CD and different polymers to further
improve the stability of these drugs. After this, the characterisations of drug/CD
complexes were done using techniques like NMR, DSC, and FTIR. Permeation
studies were done with hydrocortisone to study the effect of different solubiliser
concentrations on the permeation. Finally, cytotoxicity studies with 2-
hydroxypropyl-ȕ&' +3ȕ&' DQG UDQGRPO\ PHWK\ODWHG ȕ-cyclodextrin
50ȕ&' ZHUH GRQH XVLQJ ZLOG-type mouse retinal explants, the terminal
deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay, and
fluorescence microscopy.
Kinetics studies showed that tacrolimus has a maximum stability between
pH 4 and 6 while difluprednate has one at around pH 5. The degradation is
vigorous in basic conditions after pH 6 for both drugs. The MS studies showed
that hydrolysis was the main cause of tacrolimus degradation in aqueous
+3ȕCD solutions. Phase-solubility studies revealed that ɴCD and its
derivatives were good solubilisers for tacrolimus, while ɶCD and its derivatives
for difluprednate. Furthermore, stability studies with CD and different polymers
showed that the stability of tacrolimus was improved with the combination of
HPɴCD and tyloxapol. But still, tacrolimus degradation was around more than
30% with 5% HPɴCD and 2% tyloxapol. A similar trend was observed in the
case of difluprednate where the drug degradation was less than 1% in the
combination system with 15% HPɶCD and 4% poloxamer 407. Studies with
tacrolimus were not continued due to the unsatisfactory stability results. After
this, the characterisations of drug/CD complex in solid- and solution-states
were done in binary (difluprednate/HPɶCD) and ternary
(difluprednate/HPɶCD/poloxamer) systems. NanoSight was used to measure
the drug/CD and drug/CD/polymer aggregates with observed increasing
micelles aggregate size with an increasing poloxamer concentration. This was
confirmed by transmission electron microscopy (TEM) studies. The solid-state
characterisation of these binary and ternary complexes done by using DSC
and FTIR showed the disappearance of the characteristic peaks confirming the
presence of an inclusion complex in our system.
Permeation studies showed that the concentration of different solubilisers
(HPɴCD, ethanol, and sodium lauryl sulfate; SLS) had a pronounced effect on
the permeation of hydrocortisone across different membrane barriers. This was
shown by the flux profiles where we observed decreasing flux values when the
concentration of HPɴCD and ethanol was increased/decreased from the
concentration when hydrocortisone was in a saturated solution. The
permeation of hydrocortisone in SLS system revealed a different profile with
decreasing flux over increasing SLS concentration.
Cytotoxicity studies showed that RMɴCD was more toxic to retinal explants
when compared to HPɴCD, which the retina can safely tolerate at levels as
high as 10 mM. Additionally, studies conducted with fluorescent forms of the
same CDs showed that both CDs can penetrate deep into the inner nuclear
layer of the retina, with some uptake by Müller cells.
7R FRQFOXGH HYHQ WKRXJK +3ȕ&' ZDV D EHWWHU VROXELOLVHU VWDELOLVHU IRU
tacrolimus among the CDs tested, tacrolimus was not adequately chemically
stable to be formulated as aqueous eye drops. In the case of difluprednate, it
ZDVSRVVLEOHWRVROXELOLVH GLIOXSUHGQDWHLQDQDTXHRXV+3Ȗ&'VROXWLRQ which is twice as much as the commercially available eye drops, and stabilise
vii in an aqueous solution using a combination of CD and polymer. However, in
order to formulate into eye drops, further studies with different excipients and
different parameters are needed. In addition to this, the solubiliser
concentration does play a critical role in the permeation capability of the drug
molecule across the barrier membrane which is, in turn, related to the
WKHUPRG\QDPLFDFWLYLW\RIWKHGUXJPROHFXOH /DVWO\ +3ȕ&'ZDVIRXQGWREHDVDIHURSWLRQWKDQ50ȕ&D for retinal drug delivery and may advance the use
of CDs in the development of drugs in this field. Hopefully, these obtained
results could be beneficial in further exploration of CDs in various fields of
ophthalmic drug delivery either as drug carriers or the drug itself.The project was funded by the European Commission for Research through
Marie Curie Initial Training Network (transMed), Grant agreement No. 765441
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