1,721,118 research outputs found
Improved performances of catalytic G-quadruplexes (G4-DNAzymes) via the chemical modifications of the DNA backbone to provide Gquadruplexes with double 3′-external G-quartets
Full text linkHere we report on the design of a new catalytic G-quadruplex-DNA system (G4-DNAzyme) based on the modification
of the DNA scaffold to provide the DNA pre-catalyst with two identical 3′-ends, known to bemore catalytically
proficient than the 5′-ends. To this end, we introduced a 5′-5′ inversion of polarity site in the middle of
the G4-forming sequences AG4A andAG6A to obtain d(3′AGG5′-5′GGA3′) (orAG2-G2A) and d(3′AGGG5′-5′GGGA3′)
(or AG3-G3A) that fold into stable G4 whose tetramolecular nature was confirmed via nuclear magnetic resonance
(NMR) and circular dichroism(CD) investigations. Both AG2-G2AandAG3-G3A display two identical external
G-quartets (3′-ends) known to interact with the cofactor hemin with a high efficiency, making the resulting
complex competent to performhemoprotein-like catalysis (G4-DNAzyme). A systematic comparison of the performances
of modified and unmodified G4s lends credence to the relevance of the modification exploited here
(5′-5′ inversion of polarity site), which represents a new chemical opportunity to improve the overall activity
of catalytic G4s
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
Méthodes et outils pour l’étude des G-quadruplex d’ADN et ARN en cellules humaines
No full textRésumé : Les G-quadruplexes (ou G4s) sont des structures alternatives d’acides nucléiques (ADN et ARN) identifiées depuis 1988. Grâce à des méthodes expérimentales variées (relevant des techniques de biophysique et biochimie) d’une part, et à des outils (bio)moléculaires ciblant les G4s (e.g., ligands de G4s, anticorps spécifiques des G4s) d’autre part, les rôles biologiques de ces superstructures riches en guanines (Gs) commencent à être bien compris : les G4s interviennent notamment dans la régulation de l’expression de gènes, de la réplication et de la transcription, dans le maintien de la structure des télomères, dans la réparation de l’ADN, etc. Les G4s jouent donc des rôles importants dans de nombreux processus clés de la cellule. Ces rôles, ainsi que leur forte densité génomique et transcriptomique, et les dysfonctions associées aux protéines en charge de leur résolution in cella (les hélicases), ont conduit à considérer les G4s comme des acteurs (et donc des cibles) important(e)s dans les maladies génétiques.Dans ce contexte, identifier des composés chimiques capables de moduler la formation de ces structures en cellules humaines apparaît être une stratégie utile non seulement pour mieux comprendre les rôles qu’elles jouent mais aussi pour le développement de traitements potentiels de ces maladies.Durant mon projet de doctorat, (I) j’ai tout d’abord identifié une molécule permettant de déstabiliser de façon fiable les G4s, le PhpC, et ce, par le développement de nouveaux tests in vitro ; (II) j’ai ensuite étudié la relation entre les G4s et les dommages à l’ADN en cellules humaines par imagerie optique via l’utilisation d’outils moléculaires polyvalents: les TASQs ; et finalement, (III) en combinant les applications des TASQs avec l’optimisation d’une méthode de purification par affinité des G4s d’ARN (G4RP), j’ai validé la capacité du PhpC à déstabiliser les G4s in cella, contribuant ainsi à la valorisation de ce composé dont les applications en recherche et en thérapie sont extrêmement prometteuses.Abstract: G-quadruplexes (G4s) are nucleic acids (DNA and RNA) alternative structures identified since 1988. Thanks to a panel of experimental methods belonging to the biophysical and biochemical techniques on the one hand, and to the use of (bio)molecular G4 tools (e.g., chemical G4 ligands, G4-specific antibodies) on the other hand, precise insights into the biological roles that these guanine (G)-rich high-order structures play have been gained: notably, G4s are involved in the regulation of gene expression, of replication and transcription in telomere maintenance and DNA repair, etc. G4s are thus key players in critical cellular processes. These roles, combined with both a high genomic and transcriptomic density and a series of dysfunctions related to the proteins in charge of their unwinding in cells (G4 helicases) led us to consider G4s as key effectors of (and thus, key targets for) genetic diseases.In this context, the identification of compounds able to modulate these G4 structures in human cells appears to be a useful strategy not only for better delineating their cellular roles but also for the development of potential treatments for G4-associated diseases.During my PhD project, (I) I identified a reliable G4-destabilizer small molecule named PhpC via the development of new in vitro assays; (II) I studied the relationship between G4s and DNA damage by optical imaging using home-made G4-specific multivalent molecular tools, the TASQs; and finally (III) combining the application of the TASQs with the optimization of a cellular G4 RNA purification method (G4RP), I validated the G4 RNA-destabilizing properties of PhpC in cella, thus contributing to the development of a molecule with possibly tremendous applications for G4-associated diseases
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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