1,720,959 research outputs found
Développement de canaux d'eau artificiels hautement efficaces pour le désalinisation de l'eau
No full textThe objective of this work is the design new types of highly efficient self-assembled artificial water channels (AWC) and the investigation of their water permselectivity and transport mechanism aiming for the transition from nanoscale to macroscale by showing of possibility of AWC-incorporated membrane fabrication. The starting point focused on the investigation of water/ion transport abilities and nature of transport mechanism of self-assembled discrete tubular dimers of rim-differentiated peralkyl-carboxylate-pillar[5]arenes (PADs). The objective was the assessment of water transport and selectivity of the transport, by describing the functioning and structural existence/stability of PADs in lipidic systems as perspective artificial water channels. By using advanced methods as X-Ray crystallography and MD simulation combined with water and ion transport investigation techniques such as Stopped-flow methods and fluorescence spectroscopy, it was proven that those channels able to form toroidal pores inside lipide bilayer, which could selectively transport water molecules up to 5.21 ×∙107 H2O/s/channel.Inspired by those results, an attempt was made to incorporate pillar[5]arenes into polymeric matrices to obtain functional materials for water desalination experiments using in-situ aggregation-interfacial polymerization method – isAGRIP. We succeeded to incorporate homogeneously PA[5] artificial water channels, which led to a ~40 % increase in water permeance with an excellent productivity of 50 L m−2h−1 under 17.5 bar of applied pressure, while maintaining high selectivity of 99.4 %.Finally, this work focused on expanding the artificial water channel family by synthesising new hydrophobic ureido derivative. These were combined with highly efficient I-quartets in order to construct novel hybrid supramolecular self-assembled water channels. Water and ion transport investigations showed that bi-component systems presents a multiple time increase single channel permeability compared to single compound systems, while no significant ion transport was detected. The highest performance was shown by the system HC8/S8-8 formed by combination of imidazol and benzsulfonamine derivatives with a permeability of almost 8.2 ×∙107 H2O/s/channel.In conclusion, this work has described several AWC systems that function as selective water filters both on a molecular as well as on macro-level.L’objectif de ce travail est la conception des nouveaux types de canaux d'eau artificiels (AWC) auto-assemblés à haute efficacité, l’étude de leur permsélectivité vers l'eau et leur mécanisme de transport envisageant la transition de l'échelle nanométrique à l'échelle macroscopique. Pour celle-là on a évalué la possibilité de fabrication de membranes incorporent à l'AWC. Le point de départ s’est concentrée sur l'étude des capacités de transport eau/ion et, de la nature du mécanisme de transport des dimères tubulaires discrets auto-assemblés de peralkyl-carboxylate-pilier [5]arènes (PAD). L'objectif était l'évaluation du transport et de la sélectivité du procès, la description du fonctionnement et de l'existence/stabilité structurelle des PAD dans les systèmes lipidiques comme potentiels canaux d'eau artificiel. En utilisant des méthodes avancées telles que la cristallographie aux rayons X et la simulation MD combinées à des techniques d'investigation du transport des ions d'eau comme la méthode Stopped Flow et la spectroscopie de fluorescence, on a montré que ces canaux sont capables à former des pores toroïdaux à l'intérieur de la bicouche lipidique. Ceux-ci ont pu transporter sélectivement les molécules d'eau jusqu’à 5,21 ×∙107 H2O/s/canal.Inspirés par ces résultats, nous avons essayé, avec success, d'incorporer du pillier[5]arène dans des matrices polymères pour obtenir des matériaux fonctionnels pour des expériences de désalinisation de l'eau. La méthode utilisé est l’agrégation et de polymérisation interfaciale in situ - isAGRIP. Nous avons réussi à incorporer d’une manière homogène des canaux d'eau artificiels en PA[5], ce qui a conduit à une augmentation de ~ 40 % de la perméance de l'eau avec une excellente productivité de 50 L m−2h−1 sous 17,5 bar de pression appliquée, tout en maintenant une sélectivité élevée de 99,4 %. .Dernièrement, on a réalisé l'expansion de la famille des canaux d'eau artificiels par la synthèse de nouveaux dérivés uréido hydrophobes. Par leur mélange avec des I-quartets hautement un nouveau canal d'eau supramoléculaire hybride auto-assemblé a été construit. Les études sur le transport de l'eau et des ions ont montré que les systèmes bi-composants ont multiplié quelques fois la perméabilité à un seul canal par rapport aux systèmes monocomposé, alors qu'aucun transport d'ions significatif n'a été détecté. La meilleure performance a été montrée par le système HC8/S8-8 formé entre les dérivés d'imidazole et de benzsulfonamine avec une perméabilité de près de 8,2 × ∙107 H2O/s/canal.En conclusion ce travail a décrit plusieurs systèmes AWC qui fonctionnent comme filtres à eau de haute sélectivité à l’échelle nano bien que a l’échelle macro
Développement de canaux d'eau artificiels hautement efficaces pour le désalinisation de l'eau
No full textThe objective of this work is the design new types of highly efficient self-assembled artificial water channels (AWC) and the investigation of their water permselectivity and transport mechanism aiming for the transition from nanoscale to macroscale by showing of possibility of AWC-incorporated membrane fabrication. The starting point focused on the investigation of water/ion transport abilities and nature of transport mechanism of self-assembled discrete tubular dimers of rim-differentiated peralkyl-carboxylate-pillar[5]arenes (PADs). The objective was the assessment of water transport and selectivity of the transport, by describing the functioning and structural existence/stability of PADs in lipidic systems as perspective artificial water channels. By using advanced methods as X-Ray crystallography and MD simulation combined with water and ion transport investigation techniques such as Stopped-flow methods and fluorescence spectroscopy, it was proven that those channels able to form toroidal pores inside lipide bilayer, which could selectively transport water molecules up to 5.21 ×∙107 H2O/s/channel.Inspired by those results, an attempt was made to incorporate pillar[5]arenes into polymeric matrices to obtain functional materials for water desalination experiments using in-situ aggregation-interfacial polymerization method – isAGRIP. We succeeded to incorporate homogeneously PA[5] artificial water channels, which led to a ~40 % increase in water permeance with an excellent productivity of 50 L m−2h−1 under 17.5 bar of applied pressure, while maintaining high selectivity of 99.4 %.Finally, this work focused on expanding the artificial water channel family by synthesising new hydrophobic ureido derivative. These were combined with highly efficient I-quartets in order to construct novel hybrid supramolecular self-assembled water channels. Water and ion transport investigations showed that bi-component systems presents a multiple time increase single channel permeability compared to single compound systems, while no significant ion transport was detected. The highest performance was shown by the system HC8/S8-8 formed by combination of imidazol and benzsulfonamine derivatives with a permeability of almost 8.2 ×∙107 H2O/s/channel.In conclusion, this work has described several AWC systems that function as selective water filters both on a molecular as well as on macro-level.L’objectif de ce travail est la conception des nouveaux types de canaux d'eau artificiels (AWC) auto-assemblés à haute efficacité, l’étude de leur permsélectivité vers l'eau et leur mécanisme de transport envisageant la transition de l'échelle nanométrique à l'échelle macroscopique. Pour celle-là on a évalué la possibilité de fabrication de membranes incorporent à l'AWC. Le point de départ s’est concentrée sur l'étude des capacités de transport eau/ion et, de la nature du mécanisme de transport des dimères tubulaires discrets auto-assemblés de peralkyl-carboxylate-pilier [5]arènes (PAD). L'objectif était l'évaluation du transport et de la sélectivité du procès, la description du fonctionnement et de l'existence/stabilité structurelle des PAD dans les systèmes lipidiques comme potentiels canaux d'eau artificiel. En utilisant des méthodes avancées telles que la cristallographie aux rayons X et la simulation MD combinées à des techniques d'investigation du transport des ions d'eau comme la méthode Stopped Flow et la spectroscopie de fluorescence, on a montré que ces canaux sont capables à former des pores toroïdaux à l'intérieur de la bicouche lipidique. Ceux-ci ont pu transporter sélectivement les molécules d'eau jusqu’à 5,21 ×∙107 H2O/s/canal.Inspirés par ces résultats, nous avons essayé, avec success, d'incorporer du pillier[5]arène dans des matrices polymères pour obtenir des matériaux fonctionnels pour des expériences de désalinisation de l'eau. La méthode utilisé est l’agrégation et de polymérisation interfaciale in situ - isAGRIP. Nous avons réussi à incorporer d’une manière homogène des canaux d'eau artificiels en PA[5], ce qui a conduit à une augmentation de ~ 40 % de la perméance de l'eau avec une excellente productivité de 50 L m−2h−1 sous 17,5 bar de pression appliquée, tout en maintenant une sélectivité élevée de 99,4 %. .Dernièrement, on a réalisé l'expansion de la famille des canaux d'eau artificiels par la synthèse de nouveaux dérivés uréido hydrophobes. Par leur mélange avec des I-quartets hautement un nouveau canal d'eau supramoléculaire hybride auto-assemblé a été construit. Les études sur le transport de l'eau et des ions ont montré que les systèmes bi-composants ont multiplié quelques fois la perméabilité à un seul canal par rapport aux systèmes monocomposé, alors qu'aucun transport d'ions significatif n'a été détecté. La meilleure performance a été montrée par le système HC8/S8-8 formé entre les dérivés d'imidazole et de benzsulfonamine avec une perméabilité de près de 8,2 × ∙107 H2O/s/canal.En conclusion ce travail a décrit plusieurs systèmes AWC qui fonctionnent comme filtres à eau de haute sélectivité à l’échelle nano bien que a l’échelle macro
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Get PDFWe 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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