1,720,979 research outputs found
Design and Fabrication of Polyvinylpyrrolidone-based Intelligent Materials Suitable for Controlled Release and Wound Treatment
No full textPolyvinylpyrrolidone (PVP) is probably one of the most utilized pharmaceutical polymers with applications ranging from blood plasma substitute to nanoparticle drug delivery since its synthesis in 1938. It is a highly biocompatible, non-toxic and transparent film-forming polymer. Although high solubility of PVP in an aqueous environment is advantageous, it still poses several problems for some applications in which sustained targeting and release are needed, or hydrophobic drug inclusion and delivery systems are to be designed. For this reason, in the field of controlled drug release, it is often used as an additive and not as a protagonist. On the other hand, in case of wound treatment, PVP can be a suitable biopolymer for the design of wound dressings due to its capacity to inhibit the crystallinity of several drugs, opening to their topical application, and its adhesive properties to the skin.
Therefore, the main goal of this Ph.D. was to demonstrate that this underestimated synthetic polymer can be a proper based material for the design, the fabrication and the formulation of new smart wound dressings for the delivery of antibiotic and antioxidant compounds.
In the first part of this Ph.D. study, PVP and acetic acid (AcOH) were used to inhibit the crystallization of the antibiotic Ciprofloxacin (Cipro) and to prepare transparent PVP foils as well as nanofiber mats. The presence of the antibiotic and the acid inside of the PVP matrix caused a plasticizer effect of these ingredients in the final mechanical properties of the films. Both films and nanofibers were able to release the Cipro, and an antibacterial synergism between acetic acid and the antibiotic were highlighted in vitro antibacterial assay. The PVP/Cipro/AcOH materials showed biocompatibility and a different rate of resorption in an in vivo wound mice model. In the second part of the Ph.D., a multifunctional polyvinylpyrrolidone/hyaluronic acid-based bilayer construct for sequential delivery of cutaneous antiseptic and antibiotic was designed and fabricated by using two scalable methodologies. The bilayer material showed strong adhesion to skin, effective antibacterial activity against three strains, biocompatibility, hemocompatibility, anti-inflammatory properties both in vitro and in vivo, resorption by the skin and accelerate the wound closure in mice model. Then, the PVP/Cipro/AcOH films and nanofibers were further characterized on an infected wound model based on ex-vivo human skin. The materials resulted non-toxic and with suitable profiles of the release of Cipro inside of the skin. Moreover, they highlighted a strong antibacterial activity against biofilms infection of Pseudomonas aeruginosa and, especially, in case of the films they were able to eradicate completely the biofilms from the skin.
Finally, PVP was combined with the dietary phenolic compounds, p-coumaric acid (PCA). The introduction of the PCA in transparent films led to an increase of the hydrophobicity of the PVP-based matrix. Indeed, changes in water contact angles, water uptake and the rate of dissolution in water were found. Furthermore, the new biocomposites were investigated as drug delivery system of two model drugs and their antioxidant and anti-inflammatory activity were analyzed in vitro and in vivo, respectively.
In conclusions, several PVP-based wound dressings were designed and fabricated, demonstrating their potential efficacy for the treatment of infected wounds, burns, and chronic wounds
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
Antioxidant coatings from elastomeric vinyl acetate-vinyl laurate copolymers with reduced bacterial adhesion
No full textA vinyl laurate-based elastomeric copolymer, developed as chewing gum base, was used to produce functional coatings with the antioxidant curcumin. Both the polymer and curcumin were dissolved in MIBK, methyl isobutyl ketone. Coatings were applied on glass but also on natural alginate and gelatin film surfaces by dip-coating. Microscopy analysis indicated that coatings had very homogenous surface and curcumin was effectively encapsulated within the polymeric matrix. In addition, curcumin-laden coatings (10 wt%) remained transparent with excellent UV filtering properties. The flexibility of alginate and gelatin films was maintained after coating, whereas their hydrophobicity and water vapor barrier properties improved. Furthermore, coating biocompatibility and low bacterial adhesion properties were confirmed by cell proliferation and bacterial surface contamination experiments, respectively. The radical scavenging activity of the coating was assessed with both DPPH and ABTS assay, revealing effective antioxidant properties. In addition, in weak acetic acid solutions, curcumin could be released in a sustained manner from the coatings. This coating can be used as a suitable option for improving the antioxidant and bacterial resistance properties of natural polymer films including food packaging or other relevant applications
Rafforzare i mezzi di attuazione e rinnovare il partenariato mondiale per lo sviluppo sostenibile
No full textIl Goal 17 è dedicato alla governance dell’attuazione a livello internazionale degli obiettivi fissati dall’Agenda 2030. Nel corso degli ultimi anni sotto l’impulso della nuova Commissione europea da una parte e dell’emergenza sanitaria dall’altra, si è assistito a un rilancio del partenariato a livello europeo, che si è ulteriormente consolidato a seguito dell’invasione dell’Ucraina. L’emergenza dei profughi ha spinto l’UE ad applicare immediatamente la Direttiva sulla Protezione Temporanea e al contempo sono stati prorogati i fondi FAMI e il fondo sicurezza interna per far fronte alle spese di accoglienza sostenute dagli Stati membri.
L’invasione dell’Ucraina e le tensioni internazionali che ne sono seguite hanno inoltre inevitabili impatti anche su altri target dell’Obiettivo 17 (in particolare Cooperazione allo sviluppo target 2 e 3) e su altri GOAL dell’Agenda ONU 2030 (in particolare GOAL 7 e GOAL 2) che saranno monitorati nei prossimi anni
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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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