1,721,050 research outputs found
Molecular mechanisms of human prion diseases
No full textAfter having proof of its transmissibility, the mysterious agent of human transmissible encephalopathies was considered for decades an unconventional invader. The subsequent characterization of a host amyloidogenic protein, segregating with infectivity, and the discovery of its encoding gene, led to the hypothesis that the infectious agent, termed prion, is a misfolded self-replicating protein. Prions are both infectious and neurotoxic, and recent evidence suggests that these properties segregate with distinct molecular forms of this protein. © 2005 Elsevier Ltd. All rights reserved
Persistence of the poliovirus genome in the cerebrospinal fluid of patients affected by post-polio syndrome
No full textTreatment of inflammatory and paraproteinemic neuropathies
No full textAcquired demyelinating and inflammatory neuropathies encompass a number of acute and chronic autoimmune conditions characterized by variable degrees of clinical involvement. These disorders, including Guillain-Barre syndrome (GBS), chronic inflammatory demyelinating polyradiculoneuropathy (CIDP), multifocal motor neuropathy (MMN), and paraprotein-associated neuropathy, have an overall annual incidence of 2-4/100,000 worldwide and are potentially treatable. Over the last few years, several investigations have helped clarify the pathogenesis of immune neuropathies and the definition of molecular targets involved in these diseases, thus providing firmer grounds for treatment with classical immunosuppressive drugs and new biological agents. In GBS and related variants, which are characterized by cellular inflammation and alterations of the blood-nerve barrier, randomized clinical trials show that plasma exchange (PE) and intravenous immunoglobulin (IVIg) are equally effective as disease-modifying treatments, although IVIg has been adopted as the favourite treatment in most centres. In CIDP, controlled clinical trials have established the efficacy of oral prednisone, PE and IVIg, with intermittent IVIg treatment or corticosteroids being usually preferred. Adding azathioprine can help keep lower the required dose of prednisone, while other immunosuppressive agents, such as cyclophosphamide and cyclosporin A may have side effects, limiting their use to selected cases. Currently, the efficacy of interferon beta and alfa is under evaluation. Controlled trials support the view that IVIg is the treatment of choice in MMN. Patients resistant to IVIg administration may benefit of treatments which deplete B cells, such as cyclophosphamide and rituximab. Demyelinating neuropathies associated with circulating paraproteins are clinically heterogeneous, depending on the reactivity and type of the monoclonal (M) protein. In many cases, neuropathies associated with IgM M proteins are not treated because of their slow progression. In patients with a disabling or rapid progression, small trials have shown short-term benefits from IVIg or PE. Recently, fludarabine and rituximab have been reported as beneficial in selected cases
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
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
- …
