1,720,961 research outputs found
Congenital absence of cartilaginous tracheal rings associated with esophageal atresia and trifurcated carina: A novel anomaly?
No full textTracheomalacia associated with esophageal atresia (EA) is a well-known condition. However, complete absence of tracheal rings (TRs) is extremely rare. Our aim is to describe a novel triad of conditions and to discuss the best treatment. An expremature male operated for EA presented with severe respiratory distress. The diagnosis of absent cartilage rings, suspected on bronchoscopy, was confirmed by optical coherence tomography. The absence of TRs was localized to a short tracheal segment, and the carina trifurcated into right upper lobe, right intermediate, and left main bronchus. The patient was treated with resection and anastomosis with a completely satisfactory course. Absence of TRs was previously reported by us in 2 other cases, both with associated EA and trifurcation of the carina. One child was treated with tracheostomy and the other with a stent, but the outcome was far from optimal. The patient with tracheostomy eventually underwent resection and anastomosis with tracheostomy closure. Congenital absence of TRs is extremely rare. Although localized, it is responsible for severe symptoms owing to complete tracheal collapse and may be misdiagnosed as tracheomalacia. In our experience, it has been associated with EA and trifurcated carina. Our limited experience suggests resection of the abnormal segment and tracheal anastomosis as the best treatment. © 2012 Elsevier Inc. All rights reserved
A new morphologic classification of congenital tracheobronchial stenosis
No full textBackground: Congenital tracheal stenoses are rare and life-threatening anomalies, associated with considerable variation in both morphology and prognosis. They have been classified previously according to the length of the stenosis or the severity of the symptoms, but not according to bronchial involvement. Methods: Data from patients who underwent slide tracheoplasty for long-segment (>50%) congenital tracheal stenosis were collected. We identified four different types of bronchial arborization (normal, n = 52; tracheal right upper lobe bronchus, n = 10; carina with "trifurcation, " n = 14; and unilateral bronchial and lung agenesis, n = 8). Each type included congenital tracheal (above the carina) or tracheobronchial (extending below the carina) stenosis. Results: Eighty-four children were enrolled in the study. Preoperative ventilation was necessary in 44 patients (52.4%; 75% in patients with a single lung), and preoperative extracorporeal membrane oxygenation was needed in 10 patients (11.9%). Preoperative tracheostomy was present in 3 patients initially treated elsewhere (3.5%), and a left pulmonary artery sling was performed in 44% (37 of 84). The overall mortality was 13% (11 of 84), 7.9% in patients with tracheal stenosis and 28.6% with tracheobronchial stenosis. No deaths occurred in patients with right upper lobe bronchus anatomy. Endoscopic procedures after slide tracheoplasty were required in 34 patients (40.4%). Stents were placed in 18 patients (21.4%), with a higher incidence in those with bronchial trifurcation (42.8%, 6 of 12). Conclusions: This classification appears useful for the morphologic characterization of congenital airway stenosis and could be the benchmark for future prospective studies on the outcome of these patients. © 2012 The Society of Thoracic Surgeons
Surgical outcome of slide tracheoplasty in patients with long congenital segment tracheal stenosis and single lung
No full textObjective: The aim of the study is to assess the surgical outcome of slide tracheoplasty in patients with congenital tracheal stenosis and single lung. Methods: Pre, intra- and postoperative data were collected. Anatomy and associated anomalies were described. Results: Seven patients (median age 5 months; range 39 days-1 year) with single lung underwent slide tracheoplasty. Single right lung was present in four patients. Associated anomalies were present in four patients (56%) including vascular ring, left pulmonary artery (LPA) sling, VACTERL (abnormalities of the vertebrae, anus, cardiovascular tree, trachea, oesophagus, renal system, and limb buds) syndrome, atrial septal defect (ASD) and aberrant left subclavian artery. Six patients (85%) needed preoperative ventilation and two (28%) needed preoperative extracorporeal membrane oxygenation (ECMO). Median postoperative ventilation was 7 days (6-35 days). Two patients needed postoperative ECMO, one of whom required preoperative ECMO. Complications occurred in five patients (71%): reintubation due to pneumothorax, pneumonia and several tracheal dilatations due to recurrent tracheal stenosis, which was eventually stented. There was one hospital death in a patient, who could not be weaned off ECMO due to severe distal malacia. At a median follow-up of 16 months (7 days-7 years), all survivors are in good clinical condition and without additional stenting. Conclusion: Slide tracheoplasty can be performed in patients with single lung and tracheal stenosis with a good surgical outcome. © 2011 European Association for Cardio-Thoracic 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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