1,721,198 research outputs found
A new breakable stent for recoarctation in early infancy: Preliminary Clinical Experience
No full textObjectivesTranscatheter treatment of aortic coarctation (CoA) via stent implantation has become an established treatment option depending on the patient's age and CoA type. BackgroundThe Osypka BabyStent((R)) is a low-profiled, balloon-expandable cobalt-chrome stent to treat aortic CoA in infants, which is breakable to permit unrestricted growth. We hereby evaluated our initial clinical experience to demonstrate the feasibility and efficacy of this new nonlicensed device, which we have occasionally implanted in critically ill patients or when redo-surgery would entail an excessively high risk. MethodsRetrospective single-center analysis of all available data during and after treatment with a BabyStent implanted in infants with considerable re-CoA or reobstruction of the aortic arch after former surgery. All interventions took place under fluoroscopy and conscious sedation with local anesthesia or general anesthesia. ResultsFive BabyStents were implanted in four infants with technical success in all of themmedian age 10 weeks (range 5-21), median bodyweight 3.8 kg (range 2.7-4.5). Aortic diameters enlarged from median 2.25 mm (range 1.5-3.3) to median 5.3 mm (range 4.6-6.0). The follow-up period lasting up to 26 months (median 8.5, range 2-26) was uneventful concerning stent-related complications. ConclusionsBabyStent((R)) implantation for recoarctation was effective. However, our initial experience with the device is limited to short- and midterm follow-up only. None of the stents was subsequently overdilated with the intention to break due to our patients' limited somatic growth so far. A multicenter survey has been initiated to justify device approval. (c) 2016 Wiley Periodicals, Inc
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
No-React (R) Injectable BioPulmonic (TM) valves re-evaluated: discouraging follow-up results
No full textOBJECTIVES: The No-React (R) Injectable BioPulmonic (TM) valve (BioIntegral) was introduced for minimally invasive off-pump replacement of the pulmonary valve almost 10 years ago. We present our mid-to long-term follow-up results. METHODS: We conducted a retrospective analysis of all 7 patients treated at our institution at the median age of 9 (range 1-24) years. The children underwent cardiac catheterization when worsening strain on the right heart was suspected after examining their medical history and/or observing significant changes on echocardiography. RESULTS: After a median follow-up period lasting 5.2 (range 0.7-6.7) years, all patients presented the indication for recatheterization, particularly because the maximum instantaneous velocity measured by Doppler had revealed systolic gradients of a median 63 (dP 18-74) mmHg across the right ventricular outflow. Catheterization confirmed severe stenosis in 2, and moderate stenosis together with moderate insufficiency in 4 patients. We observed two principal failure mechanisms: technical problems resulting from poor alignment to the right ventricular outflow tract and structural problems leading to neointimal proliferation even in cases with appropriate prosthesis positioning. At median of 5.7 (0.7-7) years after implantation, 6 of the 7 patients underwent valve rereplacement. Redo surgery was necessary in 3, and percutaneous valve-in-valve implantation in the remaining 3 patients. Histological analysis of two explanted valves confirmed significant neointima proliferation and thickened valve cusps leading to stenosis of the graft. CONCLUSIONS: These mid-term results after implantation of the No-React (R) Injectable BioPulmonic (TM) valve are disappointing. Graft failure was mainly due to neointimal formation and valve malposition
Surgically placed radiopaque markers: Proof‐of‐concept of a novel technique to facilitate percutaneous interventions in neonates and infants
No full textEntwicklung eines Risikostratifizierungsmodells zur Sterblichkeit nach kardiochirurgischen Eingriffen bei Kindern mit kongenitalen Herzfehlern
No full textKongenitale Herzfehler stellen die häufigste angeborene Organfehlbildung beim Neugeborenen dar. Kinderkardiochirurgische Eingriffe bei angeborenen Herzfehlern sind trotz großer Fortschritte vor allem bei Säuglingen noch immer mit einer relevanten Letalität assoziiert. Die Etablierung von Risikostratifizierungsmodellen trägt zu einer Verbesserung der Versorgungsqualität und einer Optimierung des klinischen Managements bei. In der jüngeren Vergangenheit wurden mit der Einführung von Klassifikationen wie dem RACHS 1-, ABC- und STAT-Kategorie erste Meilensteine hinsichtlich einer besseren Risiko stratifizierung gelegt. Ziel dieser Arbeit war die Entwicklung eines durch die Hinzunahme von Patientenfaktoren verbesserten Risikostratifizierungsmodells zum frühen Abschätzen der 30-Tagesletalität nach KHC-Eingriffen. Hierbei sollten die eingehenden Parameter in der klinischen Routine leicht und schnell verfügbar sein. Ausgehend von den vier Variablen Alter, STAT-Kategorie, Aortenabklemmzeit und Laktatkonzentration wurde mittels maschinellen Lernens und interner Kreuzvalidierung ein Modell zur Einschätzung der Überlebenswahrscheinlichkeit 24 Stunden postoperativ entwickelt. Die untersuchte Kohorte umfasste 585 Eingriffe, die zwischen 01/2014 und 12/2019 am Universitätsklinikum Freiburg – Universitäts Herzzentrum durchgeführt wurden. Das entstandene Freiburger Risikostratifizierungsmodell zeigte eine sehr gute Diskrimination (AUC 0,9) und eine Verbesserung der Vorhersagekraft im Vergleich zur reinen STAT Kategorie (AUC 0,77). Bei einem Schwellenwert von 0,4 ergab sich eine Sensitivität von 90,6 % und eine Spezifität von 76,5 %, was zu 3 falsch-negativen und 130 falsch-positiven Ergebnissen führte. Das im Rahmen der Promotionsarbeit entwickelte Risikostratifizierungsmodell wurde bereits in einer zweiten Kohorte extern validiert. Auch in diesem Zusammenhang zeigte sich eine sehr gute Performanz des Modells, sodass dieses aktuell in die klinische Routine implementiert wird
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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