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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
Developmental expression of intermediate filament proteins in the chick embryo retina: in vivo and in vitro comparison.
No full textAn immunocytochemical study was performed on the chick embryo retina to detect the changes in intermediate filament (IF) composition in correlation with development. Results showed that all three major neurofilament subunits (NF L, M and H) were expressed from very immature neurons at the same time. No delayed expression of NF-H was observed. Vimentin (VT) was also present from very early stages in both neuronal and glial cells, but it was not detectable at hatching. Its distribution changed in retinal layers throughout development. It co-existed with NF in neurons, and conversely, it preceded the appearance of the typical glial fibrillar acidic protein (GFA-P), which was detected in radial fibres of Muller cells from day 16 of incubation. These in vivo data were compared with immunocytochemical staining of retinal cultures, grown either on collagen or on polylysine. NF-L and GFA-P were not detectable in vitro. Moreover, the early expression of NF subunits was shown to be influenced by the type of substratum. The contemporary presence of vimentin and neurofilaments was clearly shown both in neuronal cell bodies and processes. The results also show that in the chick retina the pattern of composition of intermediate filaments changes with maturation. Moreover, in vitro conditions influence the expression of IF components. These data are of interest when performing in vitro analysis of the effect of exogenous substances affecting neuronal maturation and differentiation
Anti-aging potential of extracts from Washingtonia filifera seeds
Full text linkThe aim of this study was to test the inhibitory effect of fruit extracts from Washingtonia filifera on skin aging-related enzymes. The pulp extracts did not exert a significant enzyme inhibition while seed extracts from W. filifera exhibit anti-elastase, anti-collagenase, and anti-tyrosinase activities. Tyrosinase was mildly inhibited while a stronger effect was observed with respect to elastase and collagenase inhibition. Alcoholic extracts provided better results than aqueous extracts. Among them, methanol extracts showed the prominent enzyme inhibitory activities being IC50 value for elastase and collagenase comparable and even better than the reference compound. The inhibition mode of the most active extracts was investigated by Lineweaver-Burk plot analysis. Seed extracts from W. filifera were also investigated for their photo-protective effect by Mansur equation and the antioxidant activity of W. filifera extract was evaluated in oxidative-stressed cells. To evaluate the safety of the extract, the effect on cell viability of human keratinocytes cells was analyzed. Methanol extract presented the best photo-protective effect and exerted an antioxidant activity in a cellular system with no cytotoxic effect. The overall results demonstrate that W. filifera extracts are promising sources of bioactive compounds that could be used in cosmetic and pharmaceutical preparation
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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