1,721,362 research outputs found
Solid-state chiral resolution mediated by stoichiometry: crystallizing etiracetam with ZnCl2
No full textChiral resolution of racemic etiracetam was achieved via co-crystallization with ZnCl2. Depending on the amount of ZnCl2 either a stable racemic compound or a stable conglomerate can be obtained. Excess ZnCl2 triggers the quantitative conversion of the racemate into the conglomerate solid; this unprecedented behaviour was investigated through a racetam/ZnCl2/solvent phase diagram
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
A spin crossover Fe<sup>II</sup><sub>4</sub>L<sub>6</sub> cage based on pyridyl-hydrazone sites
No full textReported here is the first FeII based supramolecular cage with pyridyl-hydrazone ligand scaffolds that exhibits temperature induced spin crossover behaviour. Density functional theory calculations were employed to investigate the cause of the occurrence of this phenomenon based on the ligand structure. These results indicate that the reported low-spin cages with pyridyl-imine sites could be reconsidered for spin crossover by carefully manipulating the functional groups in the ligand system
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
Structuur bepaling van cyclohexene nucleinezuur duplexen door middel van x-stralen diffractie.
No full textHet ontwikkelen van de cyclohexeennucleïnezuren kadert in het antisense-onderzoek. De antisense-methode biedt de mogelijkheid om niet alleen genetische ziekten zoals kanker, maar ook HIV te genezen. Een antisense geneesmiddel is een oligonucleotide dat selectief met mRNA bindt om zo de productie van bepaalde eiwitten te blokkeren. Deze oligonucleotiden moeten aan een aantal voorwaarden voldoen, zo moeten ze chemisch en enzymatisch stabiel zijn. De mogelijkheid om RNaseH te activeren is een pluspunt omdat RNaseH selectief de RNA-streng in DNA/RNA-hybriden afbreekt. In deze thesis is het effect van één of meer ingebouwde cyclohexeenresidus op de driedimensionale structuur van nucleïnezuren nagegaan. In een eerste deel werd een cyclohexeenresidu ingebouwd in de welbekende Dickerson-sequentie CGCGAA*TTCGCG. Het cyclohexeenresidu (A*) veroorzaakte geen grote vervorming van de B-type structuur, wat een bewijs is voor de flexibiliteit van het cyclohexeenresidu. Deze Dickerson-sequentie met het gemodificeerde adenineresidu kristalliseerde uit in de ruimtegroep P2221, wat vrij uitzonderlijk is omdat nog geen enkele nucleïnezuursequentie tot nu toe in deze ruimtegroep uitkristalliseerde. Omdat het mogelijk is dat twee cyclohexeenresidus in tegenoverstaande strengen elkaar conformationeel beïnvloeden, werd de heptameersequentie GCGT*GCG/CGCACGC (met T* een cyclohexeenresidu) onderzocht. Ondanks hoge-resolutie metingen op kristallen van de heptameersequentie, kon de structuur niet opgelost worden. Verscheidene technieken (SAD phasing en direct methods) zijn gepland om de nodige fase-informatie te verkrijgen. In een volgend hoofdstuk is de kristalstructuur van een volledig gemodificeerd cyclohexeenoctameer GTGTACAC beschreven. Fase-informatie werd bekomen door middel van moleculaire verplaatsings-technieken met de hexitolstructuur als model in de rhombohedrische ruimtegroep R32. Het octameer is echter opgebouwd uit linksdraaiende bouwstenen, wat aanleiding geeft tot een linksdraaiende helix. In het kristalrooster stapelen de helices op elkaar en vormen zo continue kolommen. Deze stapeling is ook de directe oorzaak van de geobserveerde wanorde. De structuur is verfijnd in twee delen die 4 baseparen ten opzichte van elkaar verschoven zijn. De biologische eenheid wordt bekomen door het toepassen van de kristallo grafische tweetallige as, net zoals bij de gemodificeerde Dickerson sequentie CGCGAA*TTCGCG. De linksdraaiende helix vertoont alle belangrijke karakteristieken van A-type DNA, zoals een grote x-displacement, geïnclineerde basenparen en typische waternetwerken. In het laatste hoofdstuk worden enkele algemene conclusies, evenals gelijkenissen en verschillen tussen de cyclohexeenresidus belicht, samen met enkele mogelijkheden voor uitbreiding in de toekomst.status: Publishe
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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