1,721,232 research outputs found
Cyclodextrin-Adamantane Host–Guest Interactions on the Surface of Biocompatible Adamantyl-Modified Glycodendrimers
No full textA series of adamantyl-modified glycodendrimers (mPPI-Gx-AdaA-C) was prepared in a two-step synthesis using two efficient reactions: (1) urea bond formation from amine and isocyanate and (2) reductive amination. H-1 NMR spectroscopy (host guest titration and ROESY experiments) was used to evaluate the graded effect of steric hindrance as a function of the number and type of oligosaccharide molecules and of the number of adamantyl (Ada) units on the complexation with monomeric beta-cyclodextrin (beta-CD). Glycosylated fourth generation PPIs showing an average substitution in adamantyl groups of 13% were found to interact with beta-CD effectively, and were considered, as candidates for further complexation studies with a polymeric cyclodextrin derivative (poly-beta-CD). The host-guest interaction features of the maltosylated dense shell glycodendrimer along with the low cytotoxicity provided the rational basis for the use of these adamantyl-functionalized glycodendrimers in the design of supramolecular systems potentially useful as healthcare materials
Self-assembly of poly(propylene imine) glycodendrimers: role of aromatic interactions in the formation of necklace- and donut-like nanostructures
No full textHere, we report on the key feature of the third and fifth generation poly(propylene imine) dendrimers, bearing on the surface hydrophobic phenyl and hydrophilic maltose groups, to self-assemble into necklace- and donut-like supramolecular complex structures after ultrasound treatment of the native aggregation state
Enabling the synthesis of homogeneous or Janus hairy nanoparticles through surface photoactivation
No full textGoing 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
Supramolecular Glycodendrimer-Based Hybrid Drugs
No full textSpecific noncovalent interactions are commonly used by nature to modulate numerous processes including cell recognition, viral adhesion, and transmembrane communications. Here we report on the design, synthesis, and preliminary characterization of new supramolecular glycodendrimer-based hybrid drugs based on adamantyl-modified glycodendrimers of third, fourth, or fifth generation (mPPI-G3-AdaB, mPPI-G4-AdaB, and mPPI-G5-AdaB) and a new heterobifunctional ligand. This component was tailored to bind through noncovalent interactions both the multimeric natural 5-HT3 receptor (through an optimized arylpiperazine pharmacophore) and the adamantyl groups located on the glycodendrimer surfaces (through a β-cyclodextrin residue) giving rise to biorelevant supramolecular constructs. © 2014 American Chemical Society
High refractive index hyperbranched polyvinylsulfides for planar one‐dimensional all‐polymer photonic crystals
No full textWe report on the growth and characterization of onedimensional
(1D) planar all-polymer photonic crystals (PhC) with
high dielectric contrast (Dn50.3) prepared by spin coating using
hyperbranched polyvinylsulfide polymers (HB-PVS) as high
refractive index material and cellulose acetate as low refractive
index material. Solution processable HB-PVS show a near ultraviolet
absorption inducing an increased refractive index in the
visible-near infrared (n51.68, k51000 nm). HBPVS:Cellulose
Acetate Distributed Bragg Reflectors show a very clear fingerprint
of the photonic band gap possessing the expected polarized
dispersion properties as a function of the incidence angle.
Moreover, engineered microcavities tuned on the weak fluorescence
spectrum of the HB-PVS show directional fluorescence
enhancement effects due to spectral redistribution of the emission
oscillator strength. The combination of all these properties
testifies the high optical quality of the obtained photonic structures
thus indicating HB-PVS as an interesting material for the
preparation of such PhC. V
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
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