1,721,000 research outputs found
Simulating bacteria-materials interactions via agent-based modeling
No full textThis work reports the outcomes of in silico simulations of the interactions between S. aureus bacteria and an antibacterial polymeric coating developed onto titanium substrates. The aim of the theoretical analysis is to develop a computational approach suitable of predicting the effective amount of antibacterial agents to load onto the polymeric coating in order to prevent titanium implants infections and at the same time to minimize cytotoxicity. The simulations results will be contrasted with experimental data
Synthesis and characterization of succinylated pectin hydrogels with enhanced swelling performances
No full textA novel polymeric material was obtained through succinylation of pectin (S-Pec), resulting in greater stability, film-forming ability, transparency, swelling, and water retention capacity compared to native pectin (Pec). Spectroscopic techniques confirmed the success of the succinylation reaction performed on pectin, employing the reaction of galacturonic acid with succinic anhydride as a model reaction under similar experimental conditions. Moreover, fluorinated succinic anhydride was used to gain insight into the succinylation degree by X-ray Photoelectron Spectroscopy, and a different thermal behavior of S-Pec compared to Pec was confirmed through thermoanalytical characterization. Additionally, the effect of cross-linking either Pec or S-Pec in the presence of divalent cations (i.e., calcium or magnesium ions) on water retention capacity and stability was tested. A significant improvement in the ability to absorb and retain water or saline solution was found for magnesium-crosslinked succinylated pectin, while the in vitro hydrogel stability was higher for the calcium-crosslinked one. The obtained polymer represents a promising substrate for the development of natural-based superabsorbent polymers
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
In Vitro Investigations on Dopamine Loaded Solid Lipid Nanoparticles
Full text linkThe progressive degeneration of nigrostriatal neurons leads to depletion of the neurotransmitter dopamine (DA) in Parkinson's disease (PD). The hydrophilicity of DA, hindering its cross of the Blood Brain Barrier, makes impossible its therapeutic administration. This work aims at investigating some physicochemical features of novel Solid Lipid Nanoparticles (SLN) intended to enhance DA brain delivery for PD patients by intranasal administration. For this aim, novel SLN were formulated in the presence of Glycol Chitosan (GCS), and it was found that SLN containing GCS and DA were smaller than DA-loaded SLN, endowed with a slightly positive zeta potential value and, remarkably, incorporated 81 % of the initial DA content. The formulated SLN were accurately characterized by Infrared Spectroscopy in Attenuated Total Reflectance mode (FT-IT/ATR) and Thermogravimetric Analysis (TGA) to highlight SLN solid-state properties as a preliminary step forward biological assay. Overall, in vitro characterization shows that SLN are promising for DA incorporation and stable from a thermal viewpoint. Further studies are in due course to test their potential for PD treatment
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
Electrochemical Strategies for Titanium Implant Polymeric Coatings: The Why and How
Full text linkAmong the several strategies aimed at polymeric coatings deposition on titanium (Ti)
and its alloys, metals commonly used in orthopaedic and orthodontic prosthesis, electrochemical
approaches have gained growing interest, thanks to their high versatility. In this review, we will
present two main electrochemical procedures to obtain stable, low cost and reliable polymeric
coatings: electrochemical polymerization and electrophoretic deposition. Distinction should be
made between bioinert films—having mainly the purpose of hindering corrosive processes of the
underlying metal—and bioactive films—capable of improving biological compatibility, avoiding
inflammation or implant-associated infection processes, and so forth. However, very often, these
two objectives have been pursued and achieved contemporaneously. Indeed, the ideal coating is a
system in which anti-corrosion, anti-infection and osseointegration can be obtained simultaneously.
The ultimate goal of all these coatings is the better control of properties and processes occurring at
the titanium interface, with a special emphasis on the cell-coating interactions. Finally, advantages
and drawbacks of these electrochemical strategies have been highlighted in the concluding remarks
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