1,721,034 research outputs found
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
Cell adhesion on 3D printed submicron patterns: a quantitative study
No full textObjectives: With an increasing life expectancy in the western societies and more people practising extreme sports, the demand for orthopaedic implants is set to increase. Orthopaedic implant loosening is one of the main causes of revision surgeries, leading to increases in the costs of patient care and patient dissatisfaction. Better osseointegration could lead to higher success rates of primary interventions. Mesenchymal stem cells (MSC) can undergo osteogenic differentiation on the implant surfaces, promoting the implant osseointegration. Alternatively, they can commit to other differentiation paths (e.g., fibroblasts) and thus hinder the osseointegration and functionality of the implant. It is therefore fundamental to promote the osteogenic differentiation of MSC at the surface of the implant to ensure enhanced osseointegration and thus its long term success. Among the available strategies that promote osteogenic differentiation, nano and micro-scale physical patterns have proved effective but the underlying mechanisms that induce these cellular changes are not yet understood. Cellular adhesion to the surface is believed to be the key process regulating mechanotransduction (i.e., extrinsic cell signalling) and subsequently, the mesenchymal stem cell osteogenic differentiation. Nevertheless, no quantitative systematic study has been performed in order to establish the relationship between the cell adhesion and the differentiation behaviour. Furthermore, the available cellular adhesion studies are only qualitative or semi-quantitative in nature. In this work, novel fluid force microscopy (FFM) technique has been employed to characterize the adhesion properties induced by a set of osteogenic and a set of non-osteogenic submicron patterns. Methods: Two sets of substrates consisting of arrays of submicron pillars with known osteogenic potential were manufactured by means of two photon polymerization. Preosteoblast mouse cells were cultured on the patterns and on a flat control surface. The adhesion properties (i.e., the force and work of adhesion) were measured by FFM after 4 and 24 hours of cell culture. The cellular behaviour picture was completed by assessing the Young’s modulus of the living cells attached on the patterns and on the control surface. Likewise, the topographical and mechanical mapping was performed by using atomic force microscopy system. Results: In this study, the adhesion of preosteoblast cells was successfully quantified on two types of submicron pattern with known osteogenic potential, and compared to cellular adhesion data on a flat control. Therefore, the fluid force microscopy (FFM) was applied for the first time. The trend indicated that cells seeded on the osteogenic substrate adhered stronger (mean force of adhesion = 159 ± 74 nN) than cells on the non-osteogenic substrate (mean force of adhesion = 108 ± 104 nN) after 24h of incubation. Moreover, the cells adopted different morphologies and spatial distribution of the Young’s modulus depending on the culture substrate.Biomedical Engineering | Bioelectronic
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
Fluidic force microscopy and atomic force microscopy unveil new insights into the interactions of preosteoblasts with 3D‐printed submicron patterns
No full textPhysical patterns represent potential surface cues for promoting osteogenic differentiation of stem cells and improving osseointegration of orthopedic implants. Understanding the early cell-surface interactions and their effects on late cellular functions is essential for a rational design of such topographies, yet still elusive. In this work, fluidic force microscopy (FluidFM) and atomic force microscopy (AFM) combined with optical and electron microscopy are used to quantitatively investigate the interaction of preosteoblasts with 3D-printed patterns after 4 and 24 h of culture. The patterns consist of pillars with the same diameter (200 nm) and interspace (700 nm) but distinct heights (500 and 1000 nm) and osteogenic properties. FluidFM reveals a higher cell adhesion strength after 24 h of culture on the taller pillars (32 +/- 7 kPa versus 21.5 +/- 12.5 kPa). This is associated with attachment of cells partly on the sidewalls of these pillars, thus requiring larger normal forces for detachment. Furthermore, the higher resistance to shear forces observed for these cells indicates an enhanced anchorage and can be related to the persistence and stability of lamellipodia. The study explains the differential cell adhesion behavior induced by different pillar heights, enabling advancements in the rational design of osteogenic patterns
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
Sport et éducation physique dans la Roumanie d’entre-deux-guerres : oui ou non ?
Full text linkL’auteur étudie la relation entre sport et éducation physique dans la Roumanie de l’entre-deux-guerres en voyant comme cela s’accompagne de la transformation du sport de loisir aristocratique en mode de vie des classes « inférieures ». Il examine aussi l’intégration du pays dans un ensemble plus vaste à travers l’adoption de sports venus d’ailleurs et le déclin des sports locaux comme l’oïna qui était le véritable sport « national » roumain avant d’être éclipsé par le football.The author studies the relation between sports and physical education in Rumania during the interwar era keeping in mind how this is accompanied by a transformation of sport from an aristocratic leisure pass-time to an integrated way of life destined to the “inferior” classes. He also examines this country’s integration in a wider geopolitical framework through the adoption of foreign sports and the subsequent decline of local sports like the oïna, which was the original Rumanian “national” sport before becoming obsolete following the introduction of football
Sport et éducation physique dans la Roumanie d’entre-deux-guerres : oui ou non ?
Full text linkL’auteur étudie la relation entre sport et éducation physique dans la Roumanie de l’entre-deux-guerres en voyant comme cela s’accompagne de la transformation du sport de loisir aristocratique en mode de vie des classes « inférieures ». Il examine aussi l’intégration du pays dans un ensemble plus vaste à travers l’adoption de sports venus d’ailleurs et le déclin des sports locaux comme l’oïna qui était le véritable sport « national » roumain avant d’être éclipsé par le football.The author studies the relation between sports and physical education in Rumania during the interwar era keeping in mind how this is accompanied by a transformation of sport from an aristocratic leisure pass-time to an integrated way of life destined to the “inferior” classes. He also examines this country’s integration in a wider geopolitical framework through the adoption of foreign sports and the subsequent decline of local sports like the oïna, which was the original Rumanian “national” sport before becoming obsolete following the introduction of football
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