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Film ibridi organico-inorganici preparati via solgel dip coating per il potenziamento delle proprietà biologiche di impianti in lega di Titanio grado 4
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Investigation of bioactivity, biocompatibility and thermal behavior of sol-gel silica glass containing a high PEG percentage
Full text linkSiO2/PEG organic–inorganic hybrid materials, which contain 60 or 70 weight percentage of PEG, were synthesized
by the sol–gel technique. Thematerialswere characterized and subjected to various tests to assess their application
in the biomedical field. The evaluation of their morphology by scanning electron microscopy (SEM) confirms the
homogeneity of the samples on the nanometer scale. Fourier transform infrared spectroscopy (FT-IR) indicated
that the two components of the hybrids (SiO2 and PEG) are linked by hydrogen bonds. This feature makes them
class I hybrids. Simultaneous thermogravimetry/differential thermal analysis (TG/DTA) was used to investigate
their thermal behavior and to establish the best temperatures for their pre-treatment. The fundamental properties
that amaterialmust have to be used in the biomedical field are biocompatibility and bioactivity. The formation of a
hydroxyapatite layer was observed on the hybrid surface by SEM/EDX and FTIR after soaking in simulated body
fluid. This indicates that the materials are able to bond to bone tissue. Moreover, the biocompatibility of SiO2/PEG
hybrids was assessed by performing WST-8 cytotoxicity tests on fibroblast cell NIH 3T3 after 24 h of exposure.
The cytotoxicity tests highlight that the cell viability is affected by the polymer percentage. The results showed
that the synthesized materials were bioactive and biocompatible. Therefore, the results obtained are encouraging
for the use of the obtained hybrids in dental or orthopedic applications
Silica-polyethylene glycol hybrids synthesized by sol-gel: Biocompatibility improvement of titanium implants by coating
No full textAlthough metallic implants are the most used in dental and orthopaedic fields, they can early fail due to low tissue tolerance or osseointegration ability. To overcome this drawback, functional coatings can be applied on the metallic surface to provide a firm fixation of the implants. The objective of the present study was twofold: to synthesize and to characterize silica/polyethylene glycol (PEG) hybrid materials using sol-gel technique and to investigate their capability to dip-coat titanium grade 4 (Ti-gr4) substrates to improve their biological properties. Various hybrid systems have been synthesized by changing the ratio between the organic and inorganic phases in order to study the influence of the polymer amount on the structure and, thus, on the properties of the coatings. Fourier transform infrared (FTIR) spectroscopy and solid state Nuclear Magnetic Resonance (NMR) allowed us to detect the formation of hydrogen bonds between the inorganic sol-gel matrix and the organic component. SEM analysis showed that high PEG content enables to obtain crack free-coating. Moreover, the effective improvement in biological properties of Ti-gr4 implants has been evaluated by performing in vitro tests. The bioactivity of the hybrid coatings has been showed by the hydroxyapatite formation on the surface of SiO2/PEG coated Ti-gr4 substrates after soaking in a simulated body fluid and the lack of cytotoxicity by the WST-8 Assay. The results showed that the coated substrates are more bioactive and biocompatible than the uncoated ones and that the bioactivity is not significantly affected by PEG amount whereas its addition makes the films more biocompatible
Biological influence of Ca/P ratio on calcium phosphate coatings by sol-gel processing
No full textThe objective of this work has been to develop low temperature sol-gel glass coatings to modify the
substrate surface and to evaluate their bioactivity and biocompatibility. Glasses, based on
SiO2·CaO·P2O5 , were synthesized by the sol-gel technique using tetraethyl orthosilicate, calcium
nitrate tetrahydrate and triethyl phosphate as precursors of SiO2, CaO and P2O5, respectively.
Those materials, still in the sol phase, have been used to coat substrates by means of the dipcoating
technique. Attenuated total reflectance Fourier transform infrared (ATR-FTIR) has been
used for characterize coatings and a microstructural analysis has been obtained using scanning
electron microscopy (SEM). The potential applications of the coatings in the biomedical field were
evaluated by bioactivity and biocompatibility tests. The coated substrate was immersed in simulated
body fluid (SBF) for 21 days and the hydroxyapatite deposition on its surface was subsequently
evaluated via SEM-EDXS analysis, as an index of bone-bonding capability. In order to study the
cell behavior and response to our silica based materials, prepared via the sol-gel method, with
various Ca/P ratio and coating substrate, we have used the human osteoblast-like U2OS cell line
Educazione sessuale e modelli videoludici: una sfida possibile
No full textAnalizzare il possibile legame tra educazione sessuale e videogiochi è come addentrarsi in un territorio minato in cui convergono pregiudizi culturali, tabù e stereotipi da ogni ambito della società.
Se da un lato esistono ancora delle forti resistenze nei confronti del videogioco come medium, come un artefatto culturale contemporaneo complesso e con ampie potenzialità legate all’apprendimento e alla costruzione di competenze trasversali, dall’altro la dimensione dell’educazione sessuale non solo non è presente nei percorsi formativi istituzionali (dalla Scuola dell’infanzia all’Università) – se non in maniera facoltativa e legata alla sensibilità degli insegnanti – ma spesso è fortemente temuta e intenzionalmente ostacolata da parte di genitori, politici e associazioni di vario stampo religioso e ideologico.
Potremmo, dunque, affermare che videogiochi e sessualità condividono lo stesso destino di marginalità, di separazione da ciò che viene considerato “idoneo” all’educazione dei giovani
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
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