1,720,973 research outputs found
Modulation of AMPA receptors in spinal motor neurons by the neuroprotective agent riluzole
No full textWe investigated the interaction of riluzole, a therapeutic agent used in amyotrophic lateral sclerosis (ALS), with alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) receptor channels in mouse spinal motor neurons in culture using whole-cell patch-clamp recording techniques. Kainate elicited concentration-dependent (EC(50) = 35 microM) inward currents in all the patched cells. These responses were mediated primarily through the activation of AMPA receptors with a negligible contribution from kainate receptors, because bath application of 100 microM GYKI53655, a potent noncompetitive AMPA receptor antagonist, completely blocked the kainate-induced currents. Riluzole (0.5-100 microM) reduced in a dose-dependent manner the kainate-induced currents with an IC(50) of 1.54 microM in all tested neurons (n = 25) and this effect was found to be reversible. The response to kainate decreased in the presence of 1 microM riluzole in all spinal motor neurons tested, without changing its EC(50), indicating a noncompetitive mechanism of inhibition. The amplitude of the responses induced by kainate under control condition and during riluzole was a linear function of the membrane potential. The reversal potential of the current was not significantly different in the two experimental conditions, whereas the total conductance of the motor neurons for the currents induced by 100 microM kainate was reduced significantly in the presence of 1 microM riluzole (P < 0.05). These results reveal an interaction of riluzole with glutamatergic neurotransmission in spinal cord motor neurons and can contribute to explain its beneficial effect in the ALS treatment
Riduzione elettrochimica monoelettronica di sali di N-alchil e N-alchilaril-3-cianopiridinio polimetilsostituiti.
No full textEpidemiologic study on clavicular fractures
No full textIntroduction: Fracture of clavicle is common, accounting for 5% to 12% of all fractures and up to 44% of injuries to the shoulder. Surprisingly,only one study was performed on a large and significative number of patients, however,it was carried out on
subjects of a little harbour city (200,000 inhabitants) whose life customs are different with respect to those of metropolitan people. Other data that emerge from investigations performed on a low number of patients are in contrast among them.We
have carried out an epidemiological study regarding prevalence and causes of the clavicular fractures occurred in patients of a wide district of our town.
Methods: Clinical records of patients who sustained, between 1981-1984 and
1990-1999 clavicular fractures, treated at our Institute,have been analyzed. Information on patient's age and causes responsible of the fracture was obtained. X-ray films,
documenting the fracture, were separately examined by two of the authors. Fractures
were classified according to Allman’s method(1967); those associated with AC or sternoclavicular dislocation were excluded. Statistical analysis was performed with the use
of Chi-squared test.
Results: Of the 20,094 patients treated at our emergency repart for a fracture during the studied period,526(2.6%) sustained a clavicular fracture (bilaterally in two cases)
(44.1% of injuries to the shoulder)p=0.001. Of the 526 patients,354 (67.3%) were
males (p:0.001). 431 fractures(81 .6%) belonged to Type I fracture (middle shaft); of
them,143 (33%) and 206 (47.8%) had, respectively, no (la) and displacement (lb) of
bone fragments; while 81 (18.8%) were comminuted fractures(Ic) (p=0.001). Of the
remaining fractures,87(16.4%) belonged to Type ll fractures (distal clavicular fracture)
(47.7% and 52.3% were not displaced and displaced fractures respectively;p=0.8).
Only 10 patients (1 .6%) had fractures of the proximal third (Type lll): undisplaced in
3 cases (llla) and displaced in 7 (lllb).l\/lean age of patients with Type l,Il and Ill fractures was, respectively 26,37 and 51 yrs; while that of patients with undislaced and
displaced fractures was 24 and 31 yrs.Prevalence of Type l fracture decreased with
age; while Type ll and lll fractures always increased in patients older than 60 years
old. A half(47.3%) of clavicular fractures occurred as a consequence of traffic accidents especially injuries resulting from falls from mopeds. No significant difference
was observed regarding seasonal prevalence of clavicular fractures.
Conclusion: In our series, prevalence of clavicular fracture is about one half compared
to Nordqvist and Petersson’s study. This discrepancy is probably due to different char-
acteristics of examined cohorts, mean age,sportive lifestyle, greater use of bycicle as
mean of trasportation. Furthermore, two thirds of our patients had a displaced frac-
ture. This frequency is higher than that revealed by Nordqvist and Petersson(42.7%),
probably because our prevalence of Type l fracture, that usually undergoes displace-
ment, was higher. Previous studies referred that 50%-82% of all fractures belongs
to Type I, 10%-18% to Type ll and 2%-10% to Type lll. these proportions are in accordance with ours. our data suggest a significant correlation between age, localization of the fracture and entity of displacement. In fact, 94% of the fractures sustained by children (<10yrs) belonged to Type I fracture and two thirds were undisplaced. type I fractures were the more frequent also in adolescents and young adults, however 71% had a displacement of bone fragments. Finally , in the elderly a low prevalence of clavicular was revealed; probably because the trauma exhaust itself in common osteoporotic areas (humeral head, wrist
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
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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