1,721,024 research outputs found
Xenx (Xenolith) : preliminary considerations of a new “all-in-one” ureteral guidewire and anti-repulsion device
No full textA new anti-retropulsion device for the endoscopic treatment of ureteral stones was evaluated for safety and potential efficacy. The XenxTM (Rocamed, Monaco-Montecarlo) is an anti-retropulsion device that operates as a normal hydrophilic guidewire when “closed” and as a nitinol ureteral mesh when “open”. We performed semirigid ureterorenoscopy and Ho:YAG Laser lithotripsy in 15 patients, with a single ureteral stone. For each procedure, the papilla was negotiated with the XenxTM, the radiopaque markers were positioned over the stone via direct visualization and the device was opened under fluoroscopic control. The ureteroscope was then retracted and reinserted beside the XenxTM. At the end of the procedure, the XenxTM was closed, and a ureteral catheter was coaxially placed and left for 24–48 h post-operation. We evaluated device positioning success with respect to pushability, ease of deployment, full expansion and fitting with the ureteral walls, kink resistance and stone retention capabilities during lithotripsy and device retrieval. Operative time, post-operative complications (Clavien-Dindo scale), ultrasound kidney stone-free rate and the hydronephrosis grade, were also recorded. At 4 weeks post-operation, the stone-free rate was assessed via non-contrast computed tomography with 1-mm slices. All procedures were successfully accomplished without complications according to the Clavien-Dindo scale. In all the cases, XenxTM was inserted successfully past the stone and opened over it. In 4/15 cases (27 %) some difficulties in pushability and kink resistance were recorded. In no case stone fragment basketing was performed. The median operative time was 24 min. At hospital discharge, 14/15 patients (93 %) were kidney stone-free. At 4 weeks, the NCCT stone-free rate was 100 %. This study demonstrated that the XenxTM is safe and effective in terms of the stone-free rate, complications and operating time. Moreover, use of the XenxTM allows the use of a basket or guide wire to be avoided
Five-year experience in live surgical demonstrations for urinary stone treatment: are outcomes compromised?
No full textLaser fiber and flexible ureterorenoscopy: the safety distance concept
Full text linkINTRODUCTION The costs of flexible ureterorenoscopes (fURS) and their repair oblige the surgeon to know the proper handling of instruments. There is a lack of evidence in the literature about the safety distance that the laser fiber should have once out from the scope to avoid instrumental damages. MATERIAL AND METHODS We performed an in-vitro observational study. Seven fURS were tested. The distance from the laser fiber tip and the fURS camera was measured at the first appearance on the endoscopic screen and when the fiber was reaching one fourth of the screen. Secondly, to evaluate the impact of the Holmium laser bubble according to the different fiber distances, an assessment of the size and shape of the bubble created at the tip of the fiber with the laser activated was done recording the images with an High Speed Camera. RESULTS The first appearance on the screen of the laser tip is different in different scopes. In all the scopes when observed that when the laser fiber was at 1⁄4 of the screen the bubble was never touching the fURS tip. CONCLUSION Even if there is a big limitation of this study due the impossibility to measure and to evaluate the damage of the fURS tip surface, we observed that when the laser fiber tip reach 1⁄4 of the screen, the bubble generated by the laser activation is never rebounding on the camera of the scope preserving it from laser damages. We can define this position as the "safety distance"
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
Live surgical demonstrations do not compromise patients safety : Results from a 5 year experience in 151 urinary stone cases
No full textAppropriate 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
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