1,720,983 research outputs found
Chronic lithium re-sizes motor neurons and induces neuronogenesis in the spinal cord of a mouse model of amyotrophic lateral sclerosis
No full textHigh-intensity exercise training induces morphological and biochemical changes in skeletal muscle
No full textSkeletal muscle shows an elevated plasticity and can adapt its metabolic and contractile properties in response to a variety of stimuli such as physical exercise. This implies a series of biochemical and morphological changes in the recruited muscle, in order to produce the more appropriate functional response dependent on the specific stimulation. To determine the effective role of physical exercise in the muscle plasticity, in the present study we investigated the effect of two different exercise protocols on fiber composition and metabolism of two specific muscles of mice: the quadriceps -a fast-twitch muscle- and the gastrocnemius -a typical slow-twitch muscle. Mice were run daily on a motorized treadmill for 8 weeks, at a velocity corresponding to 60% (low-intensity exercise) or 90% (high-intensity exercise) of the maximal running velocity previously determined by an incremental exercise test. We found that at the end of training the body weight was significantly increased in highintensity exercise mice (18.2 ± 1.4 %) compared to low-intensity exercise (8.7 ± 0.6 %) and control (12.7 ± 0.5 %) groups, and it was lesser in low-intensity exercise mice compared to controls. In contrast, the food intake of both exercise training mice was greater compared to control group. Whereas low-intensity exercise mice, despite consumed significantly more food compared to control mice, increased the weight lesser, the weight increase of high-intensity exercise mice, that consumed significantly more food compared to other experimental groups, was significantly greater. These effects were accompanied by a progressive reduction in blood lactate levels at the end of training in both the exercised mice compared with controls; in particular, blood lactate levels after highintensity exercise were significantly lower than those measured in low-intensity exercise mice. Moreover, in the present study we demonstrated that high-intensity exercise training produced a significant increase in the expression of mitochondrial complex enzymes (significant for the enzymes corresponding to the Complex IV, II and I of mitochondrial chain) both in gastrocnemius and quadriceps muscle, compared with controls. These changes were associated with an increase in the amount of slow fibers in both these muscle of high-intensity exercise mice. No changing in the expression of mitochondrial enzymes and in the percentage of slow fibers were found in low-intensity exercise mice
The effects of Locus Coeruleus and norepinephrine in methamphetamine toxicity
No full textThe activity of locus coeruleus (LC) neurons has been extensively investigated in a variety of behavioural states. In fact this norepinephrine (NE)-containing nucleus modulates many physiological and pathological conditions including the sleep-waking cycle, movement disorders, mood alterations, convulsive seizures, and the effects of drugs such as psychostimulants and opioids. This review focuses on the modulation exerted by central NE pathways on the behavioural and neurotoxic effects produced by the psychostimulant methamphetamine, essentially the modulation of the activity of mesencephalic dopamine (DA) neurons. In fact, although NE in itself mediates some behavioural effects induced by methamphetamine, NE modulation of DA release is pivotal for methamphetamine-induced behavioural states and neurotoxicity. These interactions are discussed on the basis of the state of the art of the functional neuroanatomy of central NE- and DA systems. Emphasis is given to those brain sites possessing a remarkable overlapping of both neurotransmitters
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
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