1,721,039 research outputs found
Oxidative damage in trout erythrocyte in response to "in vitro" copper exposure
No full textThe oxidative action of copper on different trout Oncorhynchus mykiss erythrocyte components was studied. The results indicate that: --cupric ions differently influence the oxidative status of two trout hemoglobin components I and IV (HbI and HbIV) having different structural and functional properties; --reactive oxygen species (ROS) production associated with hemoglobins autoxidation is not influenced by the presence of copper sulfate; --the susceptibility to hemolysis increases in the presence of copper only when the erythrocyte suspension is incubated in air; the effect of copper is almost absent for carbon monoxide-saturated erythrocyte suspensions; --DNA damage due to copper was not observed in our experimental conditions. The data obtained are important for the analysis of the environmental risks produced by copper on fish
Bilingualism and aging ; Why research should continue
No full textWhether bilingualism acts positively against neurocognitive decline is intensely debated. Although some reasons for it might be ideological, variability in sampling procedures and experimental design represent potential sources of inconsistency among studies. In this paper, we contend that bilingualism renders the extra-years of life of an increasingly long-lived population cognitively healthy, but only under specific conditions such as continuous practice and immersion in bilingual environments. We thus disagree with some authors' recommendation that bilingualism be removed from consideration as a neuroprotective factor. We suggest, at the same time, that bilingualism should not be treated as axiologically superior to other environmental measures that promise to contrast the progressive loss of functional independence with increasing age. We conclude by emphasizing the need to evaluate the protective effects of L2-learning on the aging brain in a multimodal intervention perspective, thereby dissociating the effects of bilingualism from those of other cognitively stimulating factors
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
Evidence for the Concreteness of Abstract Language: A Meta-Analysis of Neuroimaging Studies
Full text linkThe neural mechanisms subserving the processing of abstract concepts remain largely debated. Even within the embodiment theoretical framework, most authors suggest that abstract concepts are coded in a linguistic propositional format, although they do not completely deny the role of sensorimotor and emotional experiences in coding it. To our knowledge, only one recent proposal puts forward that the processing of concrete and abstract concepts relies on the same mechanisms, with the only difference being in the complexity of the underlying experiences. In this paper, we performed a meta-analysis using the Activation Likelihood Estimates (ALE) method on 33 functional neuroimaging studies that considered activations related to abstract and concrete concepts. The results suggest that (1) concrete and abstract concepts share the recruitment of the temporo-fronto-parietal circuits normally involved in the interactions with the physical world, (2) processing concrete concepts recruits fronto-parietal areas better than abstract concepts, and (3) abstract concepts recruit Broca’s region more strongly than concrete ones. Based on anatomical and physiological evidence, Broca’s region is not only a linguistic region mainly devoted to speech production, but it is endowed with complex motor representations of different biological effectors. Hence, we propose that the stronger recruitment of this region for abstract concepts is expression of the complex sensorimotor experiences underlying it, rather than evidence of a purely linguistic format of its processing
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
Lutein, zeaxanthin and astaxanthin protect against DNA damage in SK-N-SH human neuroblastoma cells induced by reactive nitrogen species.
No full textThe purpose of this study was to evaluate the ability of the predominant carotenoids (lutein and zeaxanthin) of the macular pigment of the human retina, to protect SK-N-SH human neuroblastoma cells against DNA damage induced by different RNOS donors. Although astaxanthin has never been isolated from the human eye, it was included in this study because its structure is very close to that of lutein and zeaxanthin and because it affords protection from UV-light. DNA damage was induced by GSNO-MEE, a nitric oxide donor, by Na(2)N(2)O(3), a nitroxyl anion donor and by SIN-1, a peroxynitrite-generating agent. DNA damage was assessed using the comet assay, a rapid and sensitive single cell gel electrophoresis technique able to detect primary DNA damage in individual cells. The tail moment parameter was used as an index of DNA damage. The values of tail moment increased in all the samples incubated with the RNOS donors, indicating DNA impairment. Data obtained show that the ability of zeaxanthin, lutein, and astaxanthin to reduce the DNA damage depends on the type of RNOS donor and the carotenoid concentration used. All the carotenoids studied were capable of protecting against DNA damage in neuroblastoma cells when the cells were exposed to GSNO-MEE. However, a different behaviour was present when the other two RNOS donors were used. The presence of a carotenoid alone (without an RNOS donor) did not cause DNA damage. Spectrophotometric studies showed that the order with which tested carotenoids reacted with RNOS was not always in agreement with the DNA protection results. The data from this study provides additional information on the activities of the macular pigment carotenoids of the human retina
Nitroxide radicals protect against DNA damage in rat epithelial cells induced by nitric oxide, nitroxyl anion and peroxynitrite.
No full textIn order to gain more knowledge on the antioxidant role of nitroxide radicals, in this study we investigate their possible protective action against DNA damage induced by nitric oxide (NO) and reactive nitrogen oxide species deriving from it, namely nitroxyl anion (NO(-)) and peroxynitrite (ONOO(-)). Rat trachea epithelial cells were exposed under aerobic conditions to (1) NO generated by 150 microM S-nitrosoglutathione monoethyl ester (GSNO-MEE), (2) NO(-) generated by 200 microM Angeli's salt (Na(2)N(2)O(3)) (3) ONOO(-) generated by 1mM SIN-1 (3-morpholino-sydnonimine) and (4) 100 microM synthesized ONOO(-), in the absence and presence of 5 microM of two indolinonic nitroxides synthesized by us and the piperidine nitroxide TEMPO (2,2,6,6-tetramethylpiperidine-1-oxyl). DNA damage was assessed using the comet assay-a rapid and sensitive, single-cell gel electrophoresis technique used to detect primary DNA damage in individual cells. The parameter tail moment, used as an index of DNA damage, showed that in all cases the nitroxides remarkably inhibited DNA strand breaks induced by the different nitrogen oxide species. All three nitroxides protect to the same extent, except in the case of synthesized peroxynitrite where the aromatic nitroxides 1 and 2 are more efficient than TEMPO. These findings are consistent with the antioxidant character of nitroxide compounds and give additional information on the potential implications for their use as therapeutic agents
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