1,720,994 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
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
Platelet gel-released supernatant modulates the angiogenic capability of human endothelial cells
No full textBackground Platelet gel is used to facilitate wound healing in virtue of the growth factors released from activated platelets at the site of lesion but little is known about the specific mechanisms underlying cellular repair Aims To evaluate in vitro cellular effects of different concentrations of platelet gel -released supernatant on endothelial cells Material and methods Platelet concentrate was produced at the Service of Immunohaematology and Transfusion of San Salvatore. Hospital of L Aquila using multiple bags Platelet gel was obtained by adding thrombin and calcium gluconate to the concentrates and then centrifuging to recover the supernatant Human umbilical vein endothelial cells were isolated from umbilical cord veins and grown in appropriate conditions To study their viability cells were treated with different concentrations of supernatant and XTT assays were performed on the 3 days following treatment Endothelial cell motility and invasiveness were assayed using modified Boyden chambers with filters coated with 0 1% gelatin (tor the motility test) or with a thick layer of the reconstituted basement membrane Matrigel (for the invasion test) The supernatant added at vinous concentrations to the lower compartment of the chamber was used as an attractant Umbilical cells were added to the upper compartment of the chamber After 4 hours (for the motility test) or 6 hours (tor the invasion test) filters were stained and the migrated cells in five high-power fields were counted Results When used at specific concentrations platelet gel-released supernatant is able to induce proliferation and to stimulate motility and invasiveness of endothelial human cells Higher concentrations induce a reversion of the stimulatory processes Conclusions There is alarge body of evidence indicating that platelets and their derivatives have the potential for a substantial therapeutic role in tissue regeneration The results of this in vitro study highlight the need for an in-depth analysis of technical protocols for the most appropriate and effective use of platelet gel for in vivo application
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
Serum CA125 level modifications in women undergoing repeated IVF cycles.
No full textIn the present paper, serum CA125 modifications in patients undergoing their first IVF cycle were compared with those of patients in their second attempt. A significant increase of this marker was detected in each group of patients at day 14 after embryo transfer. However, the level of CA125 monitored in the patients in their second attempt was significantly higher than that determined in patients undergoing their first ovarian stimulation. This condition does not influence either ovarian response or oocyte and embryo quality. Moreover similar IVF outcome was obtained. Therefore we propose that patients undergoing repeated assisted reproductive technology (ART) cycles may suffer from ovarian surface epithelial damage and/or altered cellular growth rate
Shedding of membrane vesicles by tumor and endothelial cells
No full textShedding of membrane vesicles is a vital phenomenon frequently observed in tumor cells and suggested to be involved in several aspects of tumor progression. Our previous studies have shown that human breast tumor cells rapidly shed membrane vesicles containing matrix metalloproteinases (MMPs). In this study we present that human umbilical vein endothelial cells (HUVEC) as well as different tumor cell lines (human ovarian cancer, CABA I and A2780, and hepatocarcinoma cell line, SK-Hep 1) shed vesicles in the extracellular medium. These vesicles carry MMPs and their inhibitors TIMPs. We conclude that tumor and endothelial cells shed MMP-containing vesicles and this may represent a mechanism for regulating focalized proteolytic activity and a way to interact with microenvironment during tumor angiogenesis
Association between GM3 and CD4-lck complex in human peripheral blood lymphocytes
No full textThe aim of this study was to further elucidate our previous observation on molecular interaction of GM3, CD4 and p56(lck) in microdomains of human peripheral blood lymphocytes (PBL). We analyzed GM3 distribution by immunoelectron microscopy and the association between GM3 and CD4-p56(lck) complex by scanning confocal microscopy and co-immunoprecipitation experiments. Scanning confocal microscopy analysis showed an uneven signal distribution of GM3 molecules over the surface of human lymphocytes. Nearly complete colocalization areas indicated that CD4 molecules were distributed in GMS-enriched plasma membrane domains. Co-immunoprecipitation experiments revealed that CD4 and p56(lck) were immunoprecipitated by IgG anti-GM3, demonstrating that GM3 tightly binds to the CD4-p56(lck) complex in human PBL. In order to verify whether GM3 association with CD4 molecules may depend on the presence of p56(lck), we analyzed this association in U937, a CD4 + and p56(lck) negative cell line, The immunoprecipitation with anti-GM3 revealed the presence of a 58 kDa band immunostained with anti-CD4 Ab, suggesting that the GM3-CD4 interaction does not require its association with p56(lck). These findings support the view that GM3 enriched-domains may represent a functional multimolecular complex involved in signal transduction and cell activation
Time-dependent release of extracellular vesicle subpopulations in tumor CABA i cells
No full textInvestigations into extracellular vesicles (EVs) have significantly increased since their role in physiological and pathological processes has become more clearly understood. Furthermore, it has become increasingly clear that several subpopulations of EVs exist, such as exosomes (EXOs) and microvesicles (MVs). Various methods and techniques used to identify and isolate the specific EVs subpopulations exist. However, these methods should be further elucidated. A deep understanding of the different factors that affect the EVs release may therefore be useful for the standardization of protocols and to establish guidelines for a more adequate analysis and correct inter-laboratory comparison. In the present study, we investigated whether composition and molecular features of EVs altered over time following a trigger stimulus. Starved CABA I cells were stimulated with FBS and conditioned medium was collected after different time intervals (30 min and 4, 8 and 18 h). The dynamic of EVs release was time-dependent, as shown by the results of scanning electron microscopy. Additionally, the time elapsed from the stimulus affected the size distribution (as highlighted by transmission electron microscopy and NanoSight assay), amount (in terms of the number of particles and protein amount) and molecular composition (CD63, HLA, Ago-2, gelatinases, and plasminogen activators) suggesting that, different EVs subpopulations were released at different time intervals following cell stimulation. Collectively, the results suggested that, parameters useful to standardize procedures for EVs isolation, including stimulation time should be considered
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