1,721,807 research outputs found
Glycosylated cellulose derivatives with regioselective distributions of pendant glucose moieties
No full textInspired by the presence of diverse carbohydrates on the surface of biological systems, we present herein a method for the synthesis of sugar-bearing polymers derived from renewable cellulose. In this paper, novel glycosylated cellulose derivatives were successfully synthesized containing a series of subsequent reactions: (1) synthesis of cellulose derivatives with pendant hydroxyl groups via nucleophilic substitution; (2) further sequential reactions containing a novel TEMPO/[bis(acetoxy)iodo]benzene (BAIB)-mediated oxidation of pendant hydroxyl groups, Schiff base formation and reduction in one-pot reaction; and (3) thiol-ene click reaction as an efficient tool to generate cellulose derivatives with pendant glucosyl groups. Furthermore, the glucosyl groups were only linked with the C6 position of anhydroglucose units (AGUs) of cellulose. Moreover, the glycosylated cellulose derivatives could be reversibly cross-linked by 1,4-phenylenediboronic acid at pH 10 and dissociated into single polymer chains by using glucose, which allow such glycolated cellulose derivatives to be interesting responsive materials
Mannosylated fluorescent cellulose‐based glycopolymers for stable uniform nanoparticles
No full textAbstract In living organisms, carbohydrate‐protein interactions play key roles in physiological and pathological processes, which are amplified by the “glycol‐cluster effect.” In this work, we synthesized novel fluorescent cellulose derivatives bearing mannose moieties via thiol‐ene click reactions by sequentially conjugating hydrophilic mannose‐oxyethoxylpropane‐thiol (Mann‐SH) and fluorescent coumarin‐oxyhexyl‐thiol (Coum‐SH) and rhodamine B‐ethyl‐thiol (RhB‐SH) to cellulose undecenoate with terminal double bonds. The amphiphilic fluorescent cellulose derivatives were converted into nanoparticles (NPs) by dropping into low ionic strength solutions (\u0026lt;0.085 M). Obtained NPs have average sizes between 240 and 554 nm depending on the solution concentrations, exhibiting uniform size distributions (PDI values \u0026lt;0.12). These uniform NPs exhibited excellent dispersion stability even at elevated temperatures. The mannose moieties were accessible to 1,4‐benzenediboronic acid (BDBA) in NaOH aqueous solutions. Under irradiation with UV light of 320–400 nm, the fluorescence of NPs increased by the formation of open‐ring rhodamine spiroamide, which could be a promising candidate for biomedical application.A novel fluorescent cellulose derivative bearing mannose, coumarin, and rhodamine moieties is synthesized via two‐step photo‐/thermo‐initiated thiol‐ene click reactions, and stable uniform nanoparticles (NPs) are formed. The mannose moieties of NPs are accessible to 1,4‐benzenediboronic acid (BDBA) in NaOH solutions, and NPs are stabilized in strong alkaline solutions at elevated temperatures. The fluorescence intensity of NPs is increased under irradiation with UV light of 320–400 nm, which allows them to be promising candidates for biomedical applications. imageChina Scholarship Council http://dx.doi.org/10.13039/501100004543Georg‐August‐Universität Göttingen http://dx.doi.org/10.13039/501100003385Verband der Chemischen Industrie http://dx.doi.org/10.13039/100007215Fonds der Chemischen Industrie (FCI
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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