1,721,045 research outputs found
Le Arenarie di Torrice: un esempio di depositi torbiditici di wedge-top basin nell'ambito del sistema di avanfossa alto miocenico dell'Appennino centro-meridionale.
No full textInterferons induce xanthine dehydrogenase gene expression in L929 cells
No full text: Human interferon-alpha A/D (Bg/II) (IFN-alpha A/D) and mouse interferon-gamma (IFN-gamma) are shown to induce xanthine dehydrogenase (XD) mRNA in L929 fibroblastic cells. XD mRNA accumulation after IFN-alpha A/D treatment is relatively fast, being already evident after 4 h and reaching its maximum after 24 h. IFN-alpha A/D is active in inducing XD mRNA at 0.1 unit/ml and it is maximally active at 10(3) units/ml. The half-life of the XD message is unaffected by IFN-alpha A/D treatment, whereas the transcriptional activity of the XD gene and the concentrations of XD heterogeneous nuclear RNA are increased by 2- and 6-fold respectively. The effect of IFN-alpha A/D on XD mRNA is insensitive to cycloheximide, suggesting that protein synthesis de novo is not required. Experiments conducted with specific inhibitors suggest that protein kinase C, cyclic AMP and arachidonic acid metabolites derived from lipoxygenase or cyclooxygenase do not act as second-messenger molecules in the induction of XD mRNA by IFN-alpha A/D. XD mRNA is also induced in NIH3T3 fibroblastic cells, but not in F9 teratocarcinoma or B16 melanoma cells after treatment with IFN-alpha A/D. NIH3T3 are the only cells so far tested that have detectable XD and xanthine oxidase activities under basal conditions and after IFN-alpha A/D treatment, although their responsiveness to the cytokine is much less than that observed in L929 cells
Catheter inversion during cavotricuspid isthmus catheter ablation: the new shaft visualization catheter reduces fluoroscopy use
Full text linkAims: Catheter ablation (CA) is the choice therapy of cavotricuspid isthmus (CTI) atrial flutter. The aim of this study was to describe our approach to improve the CTI ablation using a zero-fluoroscopy (ZF). The procedural difficulties could be related to anatomical characteristics of the CTI. Methods: One hundred eighty-eight patients that performed CA of CTI were retrospectively and consecutively evaluated between 2017 and 2019. The studied population was divided into two groups. Eighty-eight patients who were undergone CA using ablation catheter without shaft visualization catheter (NSV) were Group 1. One hundred patients were undergone CA using ablation catheter with a shaft visualization (SV); they were Group 2. The catheter was looped at the Eustachian ridge after 200 seconds of radiofrequencies (RF) without elimination of local electrogram. Results: A conduction line block of CTI was obtained in all patients of Group 2 using a ZF approach. In 16 patients of Group 1, the catheter inversion was obtained using fluoroscopy to avoid damages during its loop. In Group 2, a complete CTI block was obtained with a catheter inversion approach in ten patients without fluoroscopy, visualizing the shaft and the tip of the ablation catheter on the electroanatomic (EAM) map. In the overall population studied the use of SV had a linear correlation with the ZF approach (r =.629; P <.001). The duration of RF was lower in Group 2 than in Group 1 (Group 1: 27.8 ± 6.3 vs Group 2: 15.6 ± 7.2 minutes; P <.01). The procedure time between two groups was lower in Group 2 than in Group 1 (Group 1: 58.4 ± 22.4 vs Group 2: 42.2 ± 15.7 minutes; P <.01). No differences between two groups were documented regarding success and complications. Conclusions: The visualization of the shaft's catheter on the EAM permitted the catheter inversion safely in order to overcome some complex CTI anatomy and obtain bidirectional block. The SV reduced procedure time, RF applications and fluoroscopy exposition during CTI ablation. © 2021 The Author
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
Global transcriptional responce to Vancomycin in Mycobacterium tuberculosis
No full textIn order to gain additional understanding of the physiological mechanisms used by bacteria to maintain surface homeostasis and to identify potential targets for new antibacterial drugs, we analysed the variation of the Mycobacterium tuberculosis transcriptional profile in response to inhibitory and subinhibitory concentrations of vancomycin. Our analysis identified 153 genes differentially regulated after exposing bacteria to a concentration of the drug ten times higher than the MIC, and 141 genes differentially expressed when bacteria were growing in a concentration of the drug eightfold lower than the MIC. Hierarchical clustering analysis indicated that the response to these different conditions is different, although with some overlap. This approach allowed us to identify several genes whose products could be involved in the protection from antibiotic stress targeting the envelope and help to confer the basal level of M. tuberculosis resistance to antibacterial drugs, such as Rv2623 (UspA-like), Rv0116c, PE20-PPE31, PspA and proteins related to toxin-antitoxin systems. Moreover, we also demonstrated that the alternative sigma factor sigma(E) confers basal resistance to vancomycin, once again underlining its importance in the physiology of the mycobacterial surface stress response
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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