1,720,960 research outputs found
Impact of acute cerebral ischemic lesions and their volume on the revascularization outcome of symptomatic carotid stenosis
No full textBackground The influence of acute cerebral ischemic lesions (CILs) on the revascularization outcome of symptomatic carotid stenosis has been scarcely investigated in the literature. This study evaluated the effect of CILs and their volume on the results of carotid revascularization in symptomatic patients. Methods All patients with symptomatic carotid artery stenosis who underwent carotid endarterectomy (CEA) or carotid artery stenting (CAS) between 2005 and 2014 were considered. CILs ipsilateral to the stenosis were identified in the preoperative cerebral computed tomography. The volume was quantified in mm3 and correlated with 30-day rates of stroke and stroke/death by χ2, multivariate analysis, Pearson correlation, and receiver operating characteristic curves. Results A total of 489 symptomatic patients were treated by CEA (327 [67%]) or CAS (162 [33%]), 186 (38%) ≤2 weeks and 303 (62%) >2 weeks from symptom onset. CEA and CAS patients had statistically similar rates of stroke (3.3% vs 5.5%; P = .27) and stroke/death (3.8% vs 5.9%; P = .22). CILs were identified in 251 patients (53%) and were associated with similar stroke and stroke/death rate compared with patients without CIL (12 [4.8%] vs 8 [3.5%], P = .46; and 14 [5.6%] vs 8 [3.5%]; P = .26, respectively). The median CIL volume was 1000 mm3 (interquartile range [IQR], 7000 mm3). Patients with postoperative stroke and stroke/death had a significantly higher preoperative CIL volume of 5100 mm3 (IQR, 31,000 mm3) vs 1000 mm3 (IQR, 7000 mm3; P = .01) and 4500 mm3 (IQR, 17,450 mm3) vs 1000 mm3 (IQR, 7000 mm3; P = .03), respectively. The receiver operating characteristic curve analysis showed a volume of 4000 mm3 was predictive of postoperative stroke with 75% sensitivity and 63% specificity. A CIL volume ≥4000 mm3 was an independent risk factor for postoperative stroke, with a stroke rate of 9.3% (n = 9) vs 1.9% (n = 3) for a CIL volume of <4000 mm3 (odds ratio, 4.6; 95% confidence interval, 1.1-19.1; P = .03). Conclusions CIL volume in symptomatic carotid stenosis seems to influence the 30-day outcome independently from the timing of carotid revascularization. A CIL volume of ≥4000 mm3 could be considered a significant predictor for postoperative stroke after carotid revascularization
Plication for the treatment of a radio-cephalic fistula with ulnar artery steal
Full text linkPurpose: Generally the steal syndrome occurs in proximal arterial-venous fistulas and only exceptionally with distal vascular access because of the high number of arteries supplying the hand. We describe a rare case of steal syndrome of a proximalized distal radio-cephalic fistula stealing from both the radial and ulnar artery through the palmar arch. Methods: An 86 year old man was admitted because of a cyanotic, swollen left hand with trophic lesions at the third finger. He had a latero-terminal radio-cephalic fistula performed in 2006 with subsequent proximalization performed four years later after failure of the first one. Duplex ultrasound examination showed a high flow within the fistula (2080 mL/min) and a retrograde perfusion of the radial artery from the ulnar artery through the palmar arch and an angiography excluded stenosis along the radial artery. Results: We treated the steal syndrome through a plication technique that was performed with careful flow variations measurement, under duplex evaluation, during the surgical procedure. That procedure was effective to maintain the fistula flow and obtain the symptoms relief. The patient was evaluated the day after the intervention and after 10 weeks. The clinical examination highlighted the resolution of hand ischemia. The Duplex Ultrasound examination showed a lower flow within the fistula (1060 mL/min) and a retrograde perfusion of the radial artery from the ulnar artery through the palmar arch with a three-phase flow. dialysis access from the fistula was never interrupted from immediately after surgery to the present date. Conclusions: Plication is an effective technique for treatment of steal syndrome requiring a short operative time and it is related to satisfying post-operative results
Ancient schwannoma mimicking a carotid body tumor A case report and review of the literature
No full textAncient Schwannoma is a type of peripheral neurogenic tumor formed by the Schwann cells presenting mainly as a benign and asymptomatic lesion. The neurilemmoma tumor appears in different sites and, in cases of cervical location, can mimic a carotid body tumor. Herein we describe a clinical case of a 51-year-old woman with latero-cervical swelling. A contrast-enhanced computed tomography scan revealed a classical wineglass image mimicking a carotid body tumor. During surgery the tumor appeared connected to the cervical sympathetic trunk without carotid involvement. The histological exam confirmed the nature of the mass which consisted of an ancient schwannoma. A subsequent systematic review of the literature on ancient schwannoma incidence and treatment confirms it being a benign and rare lesion primarily treatable with open surgery. KEY WORDS: Ancient Schwannoma, Carotid body tumor, Carotid artery, Vascular surgery
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
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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