1,720,969 research outputs found
Multifunctional cyclodextrin derivatives for digital light processing 3D-printing
Get PDFL'abstract è presente nell'allegato / the abstract is in the attachmen
From polysaccharides to UV-curable biorenewable organo/hydrogels for methylene blue removal
Get PDFBiorenewable "all-starch"-derived organo/hydrogels (OHGs) were prepared via "green" and fast UV-curing and tested as bio-adsorbents for the removal of methylene blue from water. Methacrylated starch (MS) and acrylated starch derivative, gamma-cyclodextrin (ACy), were synthetized for use as OHG precursors for the photopolymerization process. Real-time photorheology confirmed the high reactivity of the prepared photocurable precursors. The mechanical properties and swelling behaviour of the photocured OHGs were examined focusing on the influence of the increasing amount of ACy. The MS-ACy OHGs were tested as innovative and environmental-friendly biorenewable materials for water treatment, using methylene blue (MB) as reference pollutant. The experimental data reveal that OHGs containing an increasing amount of ACy show not only superior mechanical strength but also sorption properties as a consequence of the high crosslinking efficiency of the acrylated cyclodextrin derivative and its ability to form host-guest inclusion complexes. Finally, the printability of these photocurable formulations via digital light processing (DLP) 3D - Printing is confirmed, envisaging the fabrication of absorbing materials with complex and application-tailored geometry, which could represent a new frontier for wastewater treatment.</p
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
Changing the surface properties with a “click”: functionalization of DLP-printed structures exploiting residual acrylate functions
Get PDFThe presence of residual acrylate functions on the surface of DLP-printed objects produced from formulations containing multifunctional monomers is here taken as a potential advantage for postfunctionalization purposes. The unreacted acrylates exposed on the surface of printed parts are used as active sites for surface-modification, exploiting the selectivity of the aza-Michael and thiol–ene “click” reactions towards C=C bonds and their ability to yield regiospecific products under mild conditions. By following this
versatile approach, the surface wettability is easily tuned by grafting either hydrophobic or hydrophilic functionalities. This allows achieving surfaces with water contact angles ranging from ∼22° to ∼106°, by
simply playing with the surface chemistry but starting from the same DLP-printed substrate. Also, surface
thiolation is explored to generate an active interface suitable for the surface-anchoring of photogenerated AgNPs. Such a strategy of post-printing functionalization may further extend the possibilities given by 3Dprinting,
because it can allow the implementation of special functions to printed parts without the need to introduce any additional component to the printable formulation
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
Maximizing the Degree of Sulfonation of Polysulfone Supports in TFC Membranes for Osmotically Driven Processes
No full textGelatin Type A from Porcine Skin Used as Co-Initiator in a Radical Photo-Initiating System
Get PDFIn the present study, a different approach for the preparation of poly(ethylene glycol) diacrylate-gelatin (PEGDA-gelatin) hydrogels was investigated. Gelatin type A from porcine skin was used as the co-initiator of a radical photo-initiating system instead of the traditional aliphatic or aromatic amines. This became possible because, upon visible-light irradiation, the amine sequences within gelatin generate initiating free-radicals through the intermolecular proton transfer in a Norrish type II reaction with camphorquinone (CQ). PEGDA-gelatin hydrogels were prepared by visible-light-induced photopolymerization. The gelatin content in the precursor formulations was varied. The influence of gelatin on the kinetics of the photocuring reaction was investigated, and it was found that gelatin fastened the rate of polymerization at all concentrations. The covalent attachment of gelatin segments within the cross-linked hydrogels was evaluated by means of attenuated total reflectance-infrared spectroscopy (ATR-FTIR) spectroscopy after solvent extraction. The thermo-mechanical properties, as well as the swelling behavior and gel content, were also investigated
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
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