1,721,022 research outputs found
Identification of muscular MRI biomarkers in Amyotrophic Lateral Sclerosis (ALS)
Full text link-Amyotrophic lateral sclerosis (ALS) is a chronic neurodegenerative disease usually assumed to target motor neurons (MNs). However, evidence of involvement of other cells types, also outside the central nervous system, has challenged this neurocentric view of ALS, which may thus be defined a multi-systemic disease. Although muscle abnormalities in ALS are habitually considered secondary to MN damage, muscle, too, can be a primary target, with dying back degeneration of MNs occurring subsequently. In recent years, efforts to clarify the pathogenesis of ALS have focused on muscle tissue. Muscle magnetic resonance imaging (MRI), shown to be useful to define prognostic biomarkers of ALS in the G93A-SOD1 mouse model, is an established diagnostic tool in inherited and acquired neuromuscular disorders. Literature data on the role of muscle MRI in ALS are scarce and heterogeneous. To study the role of muscle MRI in the diagnosis and prognosis of ALS, we proposed two cross-sectional and one longitudinal studies.
In the first study we compared qualitative T1-w images of hand, paraspinal and lower limb muscles in newly diagnosed ALS patients and in age-matched healthy controls (HCs) to look for evidence of muscular atrophy and remodelling (i.e. fatty substitution) and to relate the radiological findings to clinical and electromyographic (EMG) data. We concluded that muscle T1-w MRI can distinguish ALS patients from HCs for specific regions (i.e. legs). MRI abnormalities could be found in pauci-symptomatic spinal muscles in bulbar-onset patients (i.e. iliopsoas). Paraspinal and leg muscles MRI may be a useful diagnostic tool in early ALS. Form these preliminary results, we planned to conduct a longitudinal study in order to investigate more in deep the role of muscle through MRI measurements as a prognostic or predictive biomarker in ALS patients.
In the second part we decided to focus the study on the role of paraspinal MRI in the diagnosis of ALS, and we qualitatively compared T1-w images in newly diagnosed ALS patients, age-matched healthy controls, patients affected by inflammatory myopathy and lumbar radiculopathy. We found that paraspinal T1-w MRI could help to distinguish spinal ALS patients from healthy and pathological controls. In particular, study of longissimus dorsi can play the role of diagnostic ALS biomarker.
In the third study we compared quantitative images (6-point Dixon GRE and multi-echo TSE T2-w obtaining Water T2 and Fat Fraction values) of lower limb muscles in ALS patients at different timepoints to look for evidence of disease progression and to relate the radiological findings to clinical data. We found that ALS patients showed acute alterations in muscles more than controls at baseline but not at following timepoints. Moreover, ALS patients and controls had no difference in fat fraction at baseline, but the difference is significant during the follow up. In conclusion, MRI pattern traces the pathological process of ALS and muscle MRI can be useful as prognostic biomarker
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
P032. Coenzyme Q-10 and migraine: a lovable relationship. The experience of a tertiary headache center
No full textHeadache and Coenzyme Q1
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
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