1,720,959 research outputs found
PREPARATION OF FUNCTIONALIZED COTTON FABRICS BY MEANS OF MELATONIN LOADED β-CYCLODEXTRIN NANOSPONGES
No full textBiofunctional textiles are a new category of advanced materials which combine conventional textiles with advanced drug delivery systems to obtain fabrics able to release active principles through skin. The work presents the synthesis of hyper cross-linked β-cyclodextrins nanosponges with the carbonyl group acting as bridge between cyclodextrin molecules. The result of the synthesis is a 3-D porous structure, where melatonin molecules have been complexed. The complex has been characterized by elemental analysis, DSC, SEM, XRD and FT-IR spectroscopy and the results confirm that melatonin interacts with the synthesized nanosponge at molecular level. Melatonin loaded nanosponges has been dispersed on cotton fibres, which have proved to be a suitable substrate for durable nanosponge adsorption. The in-vitro release tests from the funtionalized fabrics have shown a zero order kinetics, which is typical of a reservoir diffusion controlled system
Chemical valorization of aldaric acids: synthesis of pyrroles from di-unsaturated aldaric lactones
No full textChemical building blocks from biomass are gaining increasing attention for the production of high
added-value chemicals.[1] Aldaric acids are sugar dicarboxylic acids, produced by oxidative hydrolysis
of biomasses, like lemon peel, apple peel, and in general pectins, with relevant potentiality to high
value polyfunctional fine chemicals, pharmaceuticals, cosmetics, and polymeric materials.[2]
Alternative oxidative processes are also known from simple hexose sugars both by chemical or
biochemical methods [2][3] via the corresponding aldonic and alduronic acids (Fig. a). However, the
just recognized potentialities of aldaric acid is mainly related to simple chemical transformations
(esterification, amidation, etc.) and this induced us to a deep analysis of the chemistry of this class of
compounds in new directions, focusing mainly on high value compounds of the pyrrole series. The
approach involves the selective dehydration of galactaric acid (as representative aldaric acid) to 2,5-
dihydroxy-muconic acid (and related keto and internal lactone forms) identifying the possible use of
these compounds in a Paal-Knorr reaction with amines (Fig. b). This allows us to better envisage the
mechanistic details of previous reports of pyrrole synthesis in low yield from aldaric acid [4] and to
obtain a large variety of 2,5-disubstituted, 2-substituted and unsubstituted N-alkyl and N-aryl pyrroles,
useful as intermediates for fine chemicals and as monomer for polymers
Elastomer compositions comprising an adduct between an sp2 hybridized carbon allotrope and a dicarboxylic acid derivative
No full textThe present invention relates to elastomer compositions comprising adducts between compounds of formula (I) preferably derived from natural sources such as mucic, pyromucic, glucaric, glycaric, galactaric, muconic acid and/or linear derivatives thereof containing ester or amide groups and/or cyclic derivatives thereof with heteroatoms in the ring, such as oxygen or nitrogen, and carbon allotropes in which the carbon is sp2 hybridized, such as for example carbon nanotubes, graphene or nanographites, carbon black
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
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