1,720,957 research outputs found
Visualisation of the Native N-type Calcium Channel
Get PDFN-type calcium channels (CaV2.2) are important for neurotransmitter release in the central and peripheral nervous system. Immunohistochemical detection of native CaV2.2 has not been possible until now due to the low expression of these channels and lack of suitable antibodies. The present study utilises the recently developed constitutive knock-in (KI) transgenic mouse, expressing CaV2.2 with an epitope tag (2 x haemagglutinin; HA) inserted in the extracellular loop between S3 and S4 of domain II (CaV2.2_HAKIKI). The tag does not affect the function of the channel when expressed in vitro (Cassidy et al., 2014). In the somatosensory nervous system, the data show that CaV2.2_HA is expressed on the cell surface of dorsal root ganglion (DRG) neurons. In the spinal cord, CaV2.2_HA is predominantly in the superficial laminae LIand LII of the dorsal horn, mainly in the primary afferent terminals, since there is a reduction in CaV2.2_HA staining following rhizotomy. Co-cultures between DRG and spinal cord neurons permit the study of CaV2.2_HA at the presynaptic terminal. Super-resolution images of the synapses formed by these co-cultures revealed the regulation of CaV2.2_HA expression at the presynaptic terminal over time in culture. Preliminary studies of TRPV1 activation by capsaicin on cell surface CaV2.2_HA was tested on cultured DRG neurons. Short incubations (20 s) with capsaicin increases CaV2.2_HA expression at the cell membrane of small, medium and large-diameter neurons. However, following longer incubations (2 to 4 min) with capsaicin, there is a substantial decrease of CaV2.2_HA immunoreactivity at the membrane. Nevertheless, further studies are required to determine whether this is mediated by a TRPV1-dependent or -independent mechanism. The CaV2.2_HAKIKI mice will be instrumental in future studies to enhance the understanding of the presynaptic role of endogenous N-type calcium channels in physiological and pathological states
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Capsaicin-Induced Endocytosis of Endogenous Presynaptic Ca(V)2.2 in DRG-Spinal Cord Co-Cultures Inhibits Presynaptic Function
Get PDFThe N-type calcium channel, Ca(V)2.2 is key to neurotransmission from the primary afferent terminals of dorsal root ganglion (DRG) neurons to their postsynaptic targets in the spinal cord. In this study, we have utilized Ca(V)2.2_HA knock-in mice, because the exofacial epitope tag in Ca(V)2.2_HA enables accurate detection and localization of endogenous Ca(V)2.2. Ca(V)2.2_HA knock-in mice were used as a source of DRGs to exclusively study the presynaptic expression of N-type calcium channels in co-cultures between DRG neurons and wild-type spinal cord neurons. Ca(V)2.2_HA is strongly expressed on the cell surface, particularly in TRPV1-positive small and medium DRG neurons. Super-resolution images of the presynaptic terminals revealed an increase in Ca(V)2.2_HA expression and increased association with the postsynaptic marker Homer over time in vitro. Brief application of the TRPV1 agonist, capsaicin, resulted in a significant down-regulation of cell surface Ca(V)2.2_HA expression in DRG neuron somata. At their presynaptic terminals, capsaicin caused a reduction in Ca(V)2.2_HA proximity to and co-localization with the active zone marker RIM 1/2, as well as a lower contribution of N-type channels to single action potential-mediated Ca(2+) influx. The mechanism of this down-regulation of Ca(V)2.2_HA involves a Rab11a-dependent trafficking process, since dominant-negative Rab11a (S25N) occludes the effect of capsaicin on presynaptic Ca(V)2.2_HA expression, and also prevents the effect of capsaicin on action potential-induced Ca(2+) influx. Taken together, these data suggest that capsaicin causes a decrease in cell surface Ca(V)2.2_HA expression in DRG terminals via a Rab11a-dependent endosomal trafficking pathway
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe 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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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