1,720,956 research outputs found
De la cible de ¹⁵⁵Gd au ¹⁵⁵Tb, un radionucléide pour la santé
No full textThe need for new medical radionuclides continues to grow as treatments become more personalised. The diversity of their decay modes and the variety of their half-lives make them valuable tools for both medical imaging and therapy. An important criterion for their development is the possibility of producing them in sufficient quantities with a high degree of chemical purity (optimisation of chelation chemistry and isotope delivery to target organs) and isotopic purity (minimisation of unnecessary radiation emitted by the radiopharmaceutical). This work has enabled us to propose an alternative method, based on the isotopic separation of a stable precursor of the radionuclide of interest, Terbium-155, with a view to its production by proton irradiation. A number of experiments were carried out, enabling us for the first time to measure the effective production cross-sections of ¹⁵⁵Tb and its contaminants, ¹⁵³Tb, ¹⁵⁴Tb, and ¹⁵⁶Tb, over an energy range compatible with that accessible with most medical cyclotrons. We have thus been able to propose some of the production parameters that will enable us to find the best compromise between a high production rate and a ¹⁵⁵Tb purity compatible with medical needs. The work is carried out within a collaboration that explores the entire production process, from the stable precursor of the radionuclide to the design of a ¹⁵⁵Tb radio-labelled molecule. In addition, comparisons with two theoretical models, TALYS and EMPIRE, have shown the need to complete the nuclear databases, at least for the production of ¹⁵⁴Tb and ¹⁵⁶Tb, in order to make them more predictive.Les besoins en nouveaux radionucléides médicaux ne cessent d'augmenter à mesure que la personnalisation des traitements se généralise. La diversité de leur mode de décroissance ainsi que la variété de leur période radioactive en font des outils précieux à la fois pour l'imagerie médicale et pour la thérapie. Un critère important pour leur développement est la possibilité de les produire en quantité suffisante avec une grande pureté chimique (optimisation de la chimie de chélation et de vectorisation de l'isotope vers les organes cible) et isotopique (minimisation des radiations inutiles émises par le radiopharmaceutique). Ce travail a permis de proposer une méthode alternative, basée sur la séparation isotopique de précurseur stable du radionucléide recherché, le Terbium-155, en vue de sa production par irradiation de protons. Plusieurs expériences ont été réalisées et ont permis, pour la première fois, de mesurer les sections efficaces de production du ¹⁵⁵Tb et de ses contaminants, les ¹⁵³,¹⁵⁴, ¹⁵⁶Tb sur une gamme en énergie compatible avec celle accessible avec la plupart des cyclotrons médicaux. Nous avons ainsi pu proposer certains des paramètres de production permettant de trouver le meilleur compromis entre un taux de production élevé et une pureté du ¹⁵⁵Tb compatible avec les besoins médicaux. Le travail est mené au sein d'une collaboration qui explore l'ensemble du processus de production, depuis le précurseur stable du radionucléide, jusqu'à la conception d'une molécule radiomarquée au ¹⁵⁵Tb. Par ailleurs, des comparaisons avec deux modèles théoriques, TALYS et EMPIRE, ont montré la nécessité de compléter les bases de données nucléaires, au moins pour la production des ¹⁵⁴Tb et ¹⁵⁶Tb, afin de les rendre plus prédictifs
De la cible de ¹⁵⁵Gd au ¹⁵⁵Tb, un radionucléide pour la santé
No full textThe need for new medical radionuclides continues to grow as treatments become more personalised. The diversity of their decay modes and the variety of their half-lives make them valuable tools for both medical imaging and therapy. An important criterion for their development is the possibility of producing them in sufficient quantities with a high degree of chemical purity (optimisation of chelation chemistry and isotope delivery to target organs) and isotopic purity (minimisation of unnecessary radiation emitted by the radiopharmaceutical). This work has enabled us to propose an alternative method, based on the isotopic separation of a stable precursor of the radionuclide of interest, Terbium-155, with a view to its production by proton irradiation. A number of experiments were carried out, enabling us for the first time to measure the effective production cross-sections of ¹⁵⁵Tb and its contaminants, ¹⁵³Tb, ¹⁵⁴Tb, and ¹⁵⁶Tb, over an energy range compatible with that accessible with most medical cyclotrons. We have thus been able to propose some of the production parameters that will enable us to find the best compromise between a high production rate and a ¹⁵⁵Tb purity compatible with medical needs. The work is carried out within a collaboration that explores the entire production process, from the stable precursor of the radionuclide to the design of a ¹⁵⁵Tb radio-labelled molecule. In addition, comparisons with two theoretical models, TALYS and EMPIRE, have shown the need to complete the nuclear databases, at least for the production of ¹⁵⁴Tb and ¹⁵⁶Tb, in order to make them more predictive.Les besoins en nouveaux radionucléides médicaux ne cessent d'augmenter à mesure que la personnalisation des traitements se généralise. La diversité de leur mode de décroissance ainsi que la variété de leur période radioactive en font des outils précieux à la fois pour l'imagerie médicale et pour la thérapie. Un critère important pour leur développement est la possibilité de les produire en quantité suffisante avec une grande pureté chimique (optimisation de la chimie de chélation et de vectorisation de l'isotope vers les organes cible) et isotopique (minimisation des radiations inutiles émises par le radiopharmaceutique). Ce travail a permis de proposer une méthode alternative, basée sur la séparation isotopique de précurseur stable du radionucléide recherché, le Terbium-155, en vue de sa production par irradiation de protons. Plusieurs expériences ont été réalisées et ont permis, pour la première fois, de mesurer les sections efficaces de production du ¹⁵⁵Tb et de ses contaminants, les ¹⁵³,¹⁵⁴, ¹⁵⁶Tb sur une gamme en énergie compatible avec celle accessible avec la plupart des cyclotrons médicaux. Nous avons ainsi pu proposer certains des paramètres de production permettant de trouver le meilleur compromis entre un taux de production élevé et une pureté du ¹⁵⁵Tb compatible avec les besoins médicaux. Le travail est mené au sein d'une collaboration qui explore l'ensemble du processus de production, depuis le précurseur stable du radionucléide, jusqu'à la conception d'une molécule radiomarquée au ¹⁵⁵Tb. Par ailleurs, des comparaisons avec deux modèles théoriques, TALYS et EMPIRE, ont montré la nécessité de compléter les bases de données nucléaires, au moins pour la production des ¹⁵⁴Tb et ¹⁵⁶Tb, afin de les rendre plus prédictifs
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
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