1,721,889 research outputs found
A functional domain on the aloha-latrotoxin molecule, distinct from the binding site, involved in cathecolamine secretion from PC12 cells: identification with monoclonal antibodies
No full textSeven monoclonal antibodies (mAbs) have been produced against alpha-latrotoxin (alpha-Latx), the toxin component of black widow spider venom that stimulates release of neurotransmitters from PC12 cells. These mAbs were characterized by an enzyme-linked immunosorbent assay and by neutralization analysis of the secretagogue properties of the toxin. The production of a panel of mAbs, possibly directed against different epitopes of alpha-Latx, provides a useful set of reagents to dissect the molecular regions of the toxin having different functions and to describe steps of its mode of action in responsive cells. Attention was focused on one of these mAbs (4C4.1), which inhibits in a dose-dependent fashion both toxin-stimulated and crude venom stimulated dopamine release from PC12 cells, prevents toxin-induced 45Ca2+ accumulation in PC12, alters toxin-dependent phosphoinositide breakdown, and prevents toxin-induced channel formation in artificial lipid bilayers. Since, within certain experimental conditions, mAb 4C4.1 is able to recognize the toxin bound to cells, we conclude that its effects were not a consequence of a direct interference with binding. On the basis of kinetic analysis of mAb interference on toxin action, expressed as accumulation of inositol phosphates and transmitter secretion, we suggest that the described effects result primarily from the blockade of an event immediately successive to binding and central for the full expression of toxin action. The availability of mAb 4C4.1 now makes possible the molecular characterization of the toxin moiety responsible for such an event
Guidelines for Designing and Developing Contents for Mobile Learning
No full textThe learning benefits deriving from the use of mobile technologies in in-field research and professional training have been demonstrated by a number of initiatives worldwide. Because learning can occur in highly variable places and conditions, the choice of mobile device and an accurate analysis of the target users are essential during the design phase of Mobile Learning applications, to identify the user scenarios and various possible experiences deriving from use of the system. The present work reconstructs previous experiences in the field of designing contents for Mobile Learning, with the aim of gleaning clear guidelines for designing and implementing highly efficacious, usable contents and courses for mobile devices. These guidelines were applied to create a course on the work of Caravaggio, to be studied using a handheld device
La televisione trasformista: come cambia la tv nell’età della convergenza
No full textIn the last twenty years, the Italian television environment has changed deeply as a result of the digital revolution and the media convergence: the contemporary television is a complex phenomenon encompassing several changes in consumption practices, in textual features and in the industrial strategies of broadcasters. The essay will explore the principals dynamics that characterize the complex relationship between Tv and its audience today: the proliferation of screens and texts, the multiplicity of production and consumption practices, the variety of touchpoints to connect TV content and viewers
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
- …
