1,720,965 research outputs found
Plasma deposited acrylic acid coatings: surface characterization and the attachment of 3T3 murine fibroblasts cell lines
No full textTwo plasma deposited acrylic acid (pdAA) surfaces with very different surface density of COOH groups, wettability and stability in water were compared about their suitability to support adhesion and growth of 3T3 murine fibroblast cell lines. Polyethylenterephtalate (PET) and tissue culture polystyrene (TCPS) were used as control. PdAA surfaces with a low surface density of COOH groups (4 +/- 1%, from the C Is XPS spectra) resulted more cell adhesive than coatings with higher COOH density
RF-Plasma Deposition and Surface Characterization of Stable (COOH)-Rich Thin Films from Cyclic L-Lactide
No full textRadiofrequency (13.56 MHz) glow discharges fed with vapors of (3S)-cis-3,6-dimethyl-1,4-dioxane-2,5-dione (cyclic L-lactide) were used to deposit stable dense COOH groups. The L-lactide is the solid intermediate compound formed during the conventional polymerization reaction of poly lactic acid (PLA), a biodegradable polymer used in biomaterials. The coatings have been characterized by means of X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FT-IR) and water contact angle (WCA) measurements. The percentage of surface carboxyl groups was determined by the Toluidine Blue O (TBO) test
Fibroblast and keratinocyte behaviour on substrates plasma-patterned with fouling and non fouling domains
No full textNano-structured cell-adhesive and cell-repulsive plasma-deposited coatings: chemical and topographical effects on keratinocyte adhesion
No full textCell-adhesive and cell-repulsive coatings have been plasma-deposited on poly(ethylene terephthalate) surfaces previously structured with nano-metric conical features by means of colloidal lithography. Surface analysis revealed that both coatings are conformal on nanostructured substrates, with their wettability depending on the substrate morphology. The effect of surface chemistry and surface topography on cell adhesion has been investigated and clarified. The adhesion of a human keratinocyte cell-line was found to be strongly dependent on the surface topography for plasma-deposited acrylic acid (cell-adhesive), and on the surface chemistry for poly(ethylene oxide)-like (cell-repulsive) coatings
Homogeneous and micro-patterned plasma processes and structuring procedures on polymer surfaces to control cell-adhesion and morphology
No full textPlasma deposition and treatment processes for micro- and nano-patterning biomedical polymers
No full textThe processes of plasma deposition and treatment for micro- and nano-patterning biomedical polymers were described. The deposition process consists of cell repulsive coatings through physical masks to produce patterned surfaces. The chemical composition of the plasma modified surfaces was tightly correlated to the relative percentage of intact ethylene oxide units in the coatings. The response of cells in terms of adhesion and spreading shows cells aligned along cell-adhesive tracks avoiding the contact with the totally cell repulsive coated areas
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
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