1,721,006 research outputs found
Hemodynamic nature of black-blood enhancement in long-term coiled cerebral aneurysms
No full textPurpose: Vessel wall imaging (VWI) with black-blood (BB) technique can demonstrate aneurysmal enhancement preluding to growth/rupture in treatment-naive cerebral aneurysms. Interestingly, recent works showed that BB enhancement may also occur in endovascularly treated aneurysms, though its meaning is controversial. Hypothesizing a flow-related mechanism of BB enhancement, we explored its relationship with incomplete occlusion status and coil packing density at DSA. Methods: We analyzed the subjects undergoing 3T MRI between January 2017 and October 2020 for a previous aneurysmal coiling. All the MRI studies included pre- and post-contrast 3D BB sequences. The presence of intra-aneurysmal pre-contrast BB signal was assessed. BB enhancement (when present) was classified as follows: (1) enhancement at the neck, (2) intrasaccular/intra-coil enhancement, and (3) peripheral enhancement. Coil packing density and aneurysmal occlusion status (according to the modified Raymond-Roy classification, MRRC) were determined on post-treatment DSA and compared with BB findings using generalized linear mixed-effect model and ANOVA. Significant p values were <0.05. Results: Forty-eight aneurysms from 44 patients were eligible for analysis. Pre-contrast BB signal was observed in 50% of the aneurysms and showed a relationship with baseline aneurysmal size. BB enhancement was detectable in 31 aneurysms (65%), being significantly associated with incomplete aneurysmal occlusion and reduced coil packing density at DSA. Conclusion: BB enhancement of coiled aneurysms is related with increasing degrees of post-coiling aneurysmal remnants and with loose coil packing density at DSA. This supports a hemodynamic interpretation of BB enhancement in long-term coiled aneurysms
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
Blood biomarkers for monitoring and prognosis of large vessel vasculitides
Full text linkPurpose of Review
Large vessel vasculitides (LVVs) are inflammatory conditions of the wall of large-sized arteries, mainly represented by giant cell arteritis (GCA) and Takayasu arteritis (TA). The inflammatory process within the vessel wall can lead to serious consequences such as development of aneurysms, strokes and blindness; therefore, early diagnosis and follow-up of LVV are fundamental. However, the arterial wall is poorly accessible and blood biomarkers are intended to help physicians not only in disease diagnosis but also in monitoring and defining the prognosis of these conditions, thus assisting therapeutic decisions and favouring personalised management. The field is the object of intense research as the identification of reliable biomarkers is likely to shed light on the mechanisms of disease progression and arterial remodelling. In this review, we will discuss the role of blood biomarkers in LVVs in the light of the latest evidence.
Recent Findings
In clinical practice, the most widely performed laboratory investigations are the erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP). However, these indices may be within normal limits during disease relapse and they are not reliable in patients receiving interleukin-6 (IL-6) receptor inhibitors. New biomarkers struggle to gain traction in clinical practice and no molecule with good accuracy has been identified to date. IL-6, a pro-inflammatory cytokine that drives CRP synthesis and increases the ESR, is one of the most promising biomarkers in the field. IL-6 analysis is increasingly performed, and serum levels are more sensitive than ESR for active GCA and might reflect persistent inflammation with high risk of relapse in patients on IL-6 receptor inhibitors. A future with biomarkers that reflect different disease features is an important aspiration. Accordingly, intense effort is being made to identify IL-6-independent inflammatory biomarkers, such as S100 proteins, pentraxin-3 and osteopontin. Moreover, metalloproteinases such as MMP2/9 and angiogenic modulators such as VEGF, YLK-40 and angiopoietins are being studied as markers of arterial remodelling. Lastly, biomarkers indicating organ damage may guide prognostic stratification as well as emergency therapeutic decisions: the most promising biomarkers so far identified are NT-proBNP, which reflects myocardial strain; pentraxin-3, which has been associated with recent optic nerve ischemia; and endothelin-1, which is associated with ischaemic complications.
Summary
Currently, the use of these molecules in clinical practice is limited because of their restricted availability, lack of sufficient studies supporting their validity and associated costs. Further evidence is required to better interpret their biological and clinical value
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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