1,721,034 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
Synthesis of amphiphilic compounds by click reaction : applications to the design of liposomes
No full textLes réactions click sont utilisées pour de nombreuses applications telle que la fonctionnalisation de la surface des liposomes. Lors de ce travail, le but a été de développer et d’appliquer une nouvelle réaction click intitulée ‘phosphonodithioformate-amine coupling’ (PAC) pour la synthèse de composés amphiphiles et pour la fonctionnalisation de la surface de liposomes. Une première partie méthodologique a eu pour but de former des briques lipidiques ‘clickables’. La réaction PAC qui a ensuite été étudiée en utilisant une amine fluorescente, s’effectue dans l’eau, à température ambiante et sans catalyse. Cette réaction permet la fonctionnalisation de liposomes sans altérer leur structure vésiculaire. L’étude de la cinétique de réaction à conduit à la classer parmi les réactions click rapides. Cette méthodologie a ensuite été appliquée pour modifier la surface de liposomes par des chaines polymères de type PEG. La deuxième partie de cette étude a été consacrée à la fonctionnalisation de la surface de liposomes par des motifs photosensibles pouvant libérer NO. Ces liposomes fonctionnalisés ont montré une libération de NO déclenchée par un stimulus lumineux. Une double fonctionnalisation des liposomes par des motifs précurseurs de NO et une sonde fluorescente a ensuite été étudiée. La production de NO et d’espèces réactives de l’oxygène (ROS) a été observée après stimulation lumineuse. L’actionbactéricide de ces espèces (NO, ROS) a été étudiée. La dernière partie de cette étude a été consacrée à l'application de la réaction click de type PAC pour préparer de nouveaux lipides cationiques. Ces composés démontrent une bonne capacité à délivrer de l'ADN dans plusieurs types cellulaires et avec une faible cytotoxicité.Click reactions are used for a large panel of applications that include the functionalization of liposomes. The goal of this study aims developing a new click reaction named ‘Phosphonodithioformate- Amine Coupling’ (PAC). This reaction was applied for the synthesis of amphiphilic compounds and to functionalize the surface of liposomes. A first methodologic part reports the synthesis of clickable lipid building blocks. These compounds were engaged in the PAC reaction with a fluorescent amine. This coupling is efficient in water, without any catalyst and at room temperature. It was applied for the modification of the surface of liposomes. Interestingly, the morphology of the liposomes was not altered by the application of the PAC reaction. Then, some liposomes were functionalized with polymeric chains (PEG). The second part of this study reports the modification of the surface of liposomes by molecules having the capacity to release NO under light exposure. Liposomes featuring a double functionalization with a NO-precursor and a fluorescent probe produce NO and Reactive Oxygen Species (ROS) triggered by light. These liposomes were studied for their potent bactericidal action. Finally, the last part of this study was devoted to applicate the new click reaction to prepare new cationic amphiphilic compounds. These compounds demonstrate a good capacity to deliver DNA in a few cell lines and with a low cytotoxicity
Design of new amphiphilic compounds, Study of their physico-chemical properties and application in gege delivery
No full textLa thérapie génique est une nouvelle approche thérapeutique prometteuse visant à traiter différents types de maladies. L’objectif de ce travail était la synthèse de nouvelles familles de phosphoramides cationiques afin d’étudier leurs propriétés physico-chimiques puis leurs propriétés de transfection. Dans un premier temps nous avons décrit la synthèse de nouveaux amphiphiles cationiques contenant une ou deux fonctions thioéther dans chaque chaine lipidique. La fonction thioéther apparait comme un élément de structure qui permet d’introduire de la fluidité dans les assemblages supramoléculaires et qui est bénéfique pour la transfection. La deuxième partie de ces travaux a été consacrée à l’élaboration de nouveaux phosphoramides cationiques formés par des chaines hydrophobes ramifiées. Ces nouveaux amphiphiles présentent la spécificité de s’assembler en phase hexagonale et font apparaitre également des efficacités de transfection intéressantes. Finalement, la dernière partie de ce projet portait sur la synthèse d’une nouvelle famille de molécules amphiphiles multipolaires incluant une structure bola-amphiphile. Ces composés ont été réparés selon trois stratégies de synthèse différentes. Ces composés ont aussi montré une bonne capacité de transfert d’ADN et de si-ARN.Gene therapy is a new promising therapeutical approach for the treatment of multiple types of diseases (monogenic diseases, cancer …). The goal of this study was the synthesis of new families of cationic phosphoramides and the study of their physico-chemical and transfection properties. First, we described the synthesis of new a new family of cationic amphiphiles containing one or two thioether function per lipid chain. The physico-chemical studies conclude that the thioether function present in the lipid chain is able to increase the fluidity of the supramolecular assemblies (liposomes). This series of compound presented a good transfection efficacies. The second part of this work was devoted to the elaboration of new cationic phosphoramides containing branched hydrophobic lipid chains. These new amphiphiles presented the singularity to auto-assemble in hexagonal phase and were efficient for transfection. Finally, the last part of this project was dedicated to the synthesis of multipolar amphiphilic compounds including one bola-amphiphile by using three different synthesis strategies. These compounds also exhibited a good capacity to deliver both DNA and si-RNA
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
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