1,721,080 research outputs found
Toxic effect of chromium on cellular metabolism.
No full textThe cytotoxic action of Cr(VI) in intact mammalian cells is strictly related to its carrier-mediated transport across the plasma membrane and its reduction to Cr(III) inside the cell. A marked decrease in the ratio of reduced/oxidized glutathione in rat thymocytes treated with dichromate indicates an involvement of glutathione in the reduction of Cr(VI) to Cr(III) in these cells. Intracellular chromium is shown to interfere with specific steps of cellular energy metabolism in that it produces severe unbalance of purine ribonucleotide pools in hamster fibroblast cultures and inhibition of mitochondrial oxygen consumption in rat thymocytes at micromolar concentrations. To what extent the effects caused by Cr(VI) are directly related to the reduction process or to the subsequent binding of Cr(III), and possibly of Cr(V), to biological molecules playing a critical role in cell physiology, remains to be elucidated
Luciani (S.), L'éclair immobile dans la plaine, philosophie et poétique du temps chez Lucrèce. (Peeters Leuven), 2000
No full textMorel Pierre-Marie. Luciani (S.), L'éclair immobile dans la plaine, philosophie et poétique du temps chez Lucrèce. (Peeters Leuven), 2000. In: Revue des Études Anciennes. Tome 103, 2001, n°3-4. pp. 560-561
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
Amiloride inhibition of Na+/Ca2+ exchange in cardiac sarcolemmal vesicles at different temperatures.
No full textDal CAD al BIM: evoluzione di acronimi o rivoluzione nel mondo della progettazione?
No full textL’adozione del BIM costituisce un approccio innovativo al mondo delle costruzioni, esteso a tutto il ciclo di vita di un manufatto edilizio: migliore qualità di progetto e della sua comunicazione, tempi ottimizzati, riduzione di errori e di costi. Questo approccio, che ha notevoli implicazioni sulla cultura della progettazione e della costruzione, è supportato da strumenti informatici dei quali si ripercorre, in questo articolo, lo sviluppo dalle origini e l’adozione da parte del mondo professionale e industriale, analizzandone elementi caratterizzanti e aspetti critici significativi
Temperature dependence of Na+/Ca2+ exchange activity in beef-heart sarcolemmal vesicles and proteoliposomes.
No full textTemperature dependence of Na+/Ca2+ exchange activity was studied in beef cardiac sarcolemmal vesicles in the absence and presence of the inhibitor amiloride and in proteoliposomes reconstituted with different lipid mixtures. Arrhenius plots for Na+/Ca2+ exchange activity in both control and amiloride-treated vesicles revealed an apparent energy of activation of 9665 +/- 585 (SE, n = 4) cal/mol, corresponding to a temperature coefficient (Q10) value of 1.70 +/- 0.05 (SE, n = 4) over the range 25-37 degrees C. When Na+/Ca2+ exchange was reconstituted into phosphatidylcholine (PC):phosphatidylserine (PS) (52:48, mol/mol), PC:PS:cholesterol (25:39:36, mol/mol), and PC:PS:distearoylphosphatidylcholine (DSPC) (31:48:21, mol/mol) proteoliposomes, the highest activity was found in PC:PS:cholesterol proteoliposomes. Arrhenius plots of Na+/Ca2+ exchange activity exhibited breakpoints at 23 degrees C (PC:PS), 33 degrees C (PC:PS:cholesterol), and 23 degrees C (PC:PS:DSPC). The increase in the thermotropic transition temperature with cholesterol could result from the condensing effect of this sterol, whereas the breaks observed with PC:PS and PC:PS:DSPC could be caused by a non-lipid-mediated membrane protein conformational change. These results indicate that the lipid microenvironment around the Na+/Ca2+ exchanger and the nature of the specific lipid-protein interactions influence the activity of this antiporter. Further evidence supporting the hypothesis that cholesterol behaves as a specific positive effector for the exchanger is also given
Building Information Modeling: la tecnologia digitale al servizio del progetto di architettura
No full textIl progetto architettonico è un insieme complesso di operazioni dove confluiscono i saperi e le professionalità di molte figure coinvolte, interagenti tra loro sostanzialmente mediante comunicazioni basate ancora su documenti cartacei. Il Building Information Modeling, il cui stato dell’arte è oggetto di questo articolo, è una strategia di progettazione che aspira ad essere molto più che un mero strumento di scambio informativo: esso si configura infatti come un metodo olistico e coordinato per assistere i tecnici progettisti, i committenti, i decision makers, i manutentori e tutti coloro i quali partecipano al progetto edilizio. Un modello digitale ottenuto con software B.I.M. consente, tra le altre cose, di integrare i dati necessari a tutti gli attori, mantenendoli sempre aggiornati, agevolando le modifiche dei componenti costruttivi in tempo reale e descrivendo il progetto in maniera disambigua
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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