1,721,036 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
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
Muscarinic receptor activation modulates neurotrophic factors production in rat Schwann-like cells derived from adipose mesenchymal stem cells.
No full textMuscarinic receptor activation modulates neurotrophic factors production in rat Schwann-like cells derived from adipose mesenchymal stem cells
Piovesana R1, Faroni A2, Soligo M3, Manni L3, Reid AJ2 & Tata AM1
1Dept. Biol and Biotech. C. Darwin, University of Rome “Sapienza”, Rome, Italy; 2Blond McIndoe Lab, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK; 3Institute of Translational Pharmacology-CNR, Rome, Italy
Peripheral nerve injury is commonly caused by direct mechanical trauma. Regeneration depends on the ability of Schwann cells (SCs) to create a favourable environment, by producing neurotrophic factors. Although SCs are effective in promoting nerve regeneration, they are not a convenient source of transplantable cells to improve outcomes after injury. Mesenchymal Stem Cells derived from adipose tissue (ASCs) seem to be a promising alternative source considering their ability to differentiate towards SC phenotype (Schwann-like).
SCs express different receptors for neurotransmitters. In particular cholinergic stimulation of M2 muscarinic receptor decreases SCs proliferation whilst upregulating myelination. Previously, we demonstrated that Schwann-like cells express muscarinic receptors; in particular the M2 receptor activation resulted in decreased proliferation and reduced migration.
In present work, we have characterised the effects mediated by muscarinic receptors on neurotrophic factors (NFs) expression and production. The selective activation of M2 receptors by arecaidine propargyl ester (APE) caused a significant decrease of the transcript levels for NFs (NGF, BDNF and GDNF), while the non-selective agonist muscarine did not influence NFs mRNA expression. By custom made Elisa Assay, we analysed the production of two different NGF forms, precursor (proNGF) and mature NGF (mNGF). APE treatment induced a decreased release of both NGF forms, whereas muscarine treatment stimulated an increased release of mNGF. Western blot analysis indicated that both agonists caused a significant decrease in the expression of the proNGF isoform at 25 kDa, which is likely involved in the modulation of apoptotic processes.
The data obtained suggest a relevant role of muscarinic receptors in the modulation of NFs production in Schwann-like cells. In particular the ability of both muscarinic agonists to negatively modulate the proNGF isoform, thereby suggesting a neuroprotective role of muscarinic receptors towards regenerating axons
Muscarinic receptor activation modulates proliferation and neurotrophic factors production in rat Schwann-like cells: implications in nerve regeneration.
No full textMuscarinic receptor activation modulates proliferation and neurotrophic factors production in rat Schwann-like cells: implications in nerve regeneration.
Theme B: Neural Excitability, Synapses, and Glia: Cellular Mechanisms
*Roberta Piovesana1,2, Alessandro Faroni2, Marzia Soligo3, Alessandro Matera1, Luigi Manni3, Valerio Magnaghi4, Adam J Reid2 & Ada Maria Tata1
1Dept. Biol and Biotech. C. Darwin, University of Rome “Sapienza”, Rome, Italy;
2Blond McIndoe Lab, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK;
3Institute of Translational Pharmacology-CNR, Rome, Italy;
4Dept.of Pharmacol and Biomol Sciences, Univ of Milan, Milan, Italy
Introduction: Peripheral nerve injury is caused by direct mechanical trauma or surgical resection secondary to tumor excision. Patients show sensory and motor loss and chronic pain. The peripheral nervous system has an intrinsic regeneration capability; nevertheless, full functional recovery is limited. Schwann Cells (SCs) play a pivotal role in the response of the axon injury, thus, SCs are an attractive therapeutic target. In fact SCs enhance nerve regeneration, producing neurotrophic factors (NFs). Unfortunately, SCs have some clinical limitations, such as the difficulty in collection and culture and a slow proliferation rate. The ideal transplantable cells should be easily accessible, proliferate rapidly in culture and successfully integrate into host tissue.
Methods: Adipose-derived stem cells (ASCs) can be differentiated in SC phenotype (Schwann-like, dASCs) following exposure to a growth factor cocktail. Gene expression was analysed by Real Time PCR; 25 kDa proNGF isoform was detected by Western Blotting analysis. By custom made Elisa Assay, the production of two different NGF forms, precursor (proNGF) and mature NGF (mNGF), have been detected. The cell migration has been analysed by wound healing assay.
Results: SCs express receptors for different neurotransmitters. Rat SCs express different muscarinic receptor subtypes. In particular, the most expressed is M2 receptor. Its activation causes a negative effect on SC proliferation, upregulating transcription factors involved in the promyelinating phase (e.g., Sox10 and Krox20) and downregulating proteins involved in the maintenance of the proliferative state (c-jun, Notch-1).
dASCs, like SCs, express functional receptors for different neurotrasmitters, including all muscarinic receptor subtypes. In present work, we characterized the effects mediated by M2 receptors in rat dASCs. As for SCs, M2 receptor activation caused a reversible decrease of cell proliferation and the inhibition of cell migration without affecting cell survival. After 24hs of M2 agonist treatment (Arecaidine propargyl ester, APE), it has been observed a significant decrease of NF expression (i.e. NGF, BDNF and GDNF) and an increase of P0 transcript level. APE treatment induced a decreased release of both NGF forms, whereas the non-selective agonist muscarine stimulated an increased release of mNGF. Both agonists caused a significant decreased expression of the 25 kDa proNGF isoform, which is involved in the modulation of apoptotic processes. Furthermore, the selective activation of M2 receptors enhanced a pronounced spindle shaped morphology in dASCs similarly to native SCs.
Conclusions: Our data demonstrate that M2 receptor activity inhibits dASCs proliferation and migration and it could improve their differentiation. Conversely muscarinic receptors activation positively modulates NFs production. These data suggest that cholinergic agonists may differently contribute to the dASC functions during nerve regeneration
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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