1,720,980 research outputs found
Effect of Low-Temperature Preservation in Optisol-GS on Preloaded, Endothelium-Out DMEK Grafts
No full textThe aim of the study was to assess different temperature ranges for the preservation of pre-loaded Descemet Membrane Endothelial Keratoplasty (DMEK) grafts in the DMEK RAPID Mini device. Methods: Three groups of 15 DMEK grafts (five per group) were pre-loaded in the DMEK RAPID Mini and preserved in Optisol-GS for 72 h at different temperatures: group A at >8 °C, group B between 2–8 °C and group C at 0.05). Endothelial cell density variation was 5.51%, 3.06% and 2.82% in groups A, B and C, respectively (p = 0.19). Total Endothelial Cell Loss (ECL) was 4.37%, 5.32% and 7.84% in groups A, B and C, respectively (p = 0.39). Endothelial cell morphology was comparable in all three groups. Conclusions: In the DMEK RAPID Mini, low temperatures (<2 °C) may affect the quality of pre-loaded grafts, inducing a higher ECL after 72 h of preservation, although no significant differences among groups could be proved. Our data would suggest maintaining grafts loaded in the DMEK RAPID Mini at temperatures between 2–8 °C for appropriate preservation
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
Anterior Chamber Inflammation and Descemet Membrane Endothelial Keratoplasty: An Anterior Segment-OCT-Based Analysis
No full textPurpose: To assess anterior chamber (AC) subclinical inflammation using a noninvasive method in patients undergoing Descemet membrane endothelial keratoplasty (DMEK). Design: Retrospective interventional case series. Participants: This study included 83 eyes from 73 patients who underwent DMEK surgery and 15 control eyes from 15 healthy individuals. Methods: The number of hyperreflective dots representing AC cells and optical density ratio (aqueous-to-air relative intensity [ARI] index) for flare quantification were calculated from anterior segment-OCT images. Aqueous-to-air relative intensity index and AC cells were calculated preoperatively and postoperatively at 1 week (T1), 1 month (T2), and 3 months (T3) after DMEK surgery. Baseline values were compared with a healthy control group. Main Outcome Measures: Anterior chamber cell count and ARI index over time; association with postoperative posterior stromal ripples (PSRs) and rebubbling. Results: Baseline ARI index was significantly higher in the DMEK group compared with controls, whereas no significant difference in AC cell count was observed. Anterior chamber cell count increased postoperatively from a median of 1.1 cells (0.6–2.1) at baseline to 3.5 (1.7–5.3) at T1 (P < 0.001), to 1.7 (1.1–3.0) at T2 (P = 0.03), and to 2.1 (1.1–4.2) at T3 (P = 0.01). The ARI index also increased from a median of 98.3 (84.1–121.9) at baseline to 142.8 (119.8–221.3) at T1 (P < 0.001) and 114.4 (101.7–140.7) at T2 (P < 0.001). Higher ARI at T1 was weakly associated with postoperative PSR (odds ratio [OR] = 1.63; 95% confidence interval [CI], 1.00–2.67; P = 0.048), whereas postoperative PSR were strongly associated with rebubbling (OR = 26.00; 95% CI, 3.20–211.18; P = 0.002). Conclusions: Anterior segment-OCT enables noninvasive detection of subclinical inflammation after DMEK surgery. The presence of markers of inflammation can increase the risk of early postoperative complications. Financial Disclosure(s): The authors have no proprietary or commercial interest in any materials discussed in this article
Three-year follow-up of eye bank prepared pre-loaded DMEK vs. pre-cut UT-DSAEK grafts
No full textPurpose: To compare the difference of long-term clinical outcomes between eye bank prepared pre-loaded (pl)-DMEK (endo-in technique) and pre-cut (pc)-ultra-thin (UT)-DSAEK grafts. Method: In this retrospective single center interventional case series, patients were treated for Fuchs endothelial corneal dystrophy (FECD) using pl-DMEK (n=47) and pc-UT-DSAEK grafts (n=42). The grafts were prepared, loaded and transported in an IOL cartridge (pl-DMEK) or in the storage media (pc-UT-DSAEK) by a single eye-bank. All the grafts were delivered by a single surgeon using bimanual pull-through technique. Post-operative outcomes were monitored up to 3 years. The main outcome measures were early post-operative complications, best corrected visual acuity (BCVA) and endothelial cell density (ECD) at years 1, 2 and 3. Result: pl-DMEK showed a significantly higher rebubbling rate (21.3%) compared to pc-UT-DSAEK (4.8%; p 0.05) compared to pc-UT-DSAEK grafts at year 1 (1745 vs 1789), year 2 (1553 vs 1495) and year 3 (1422 vs 1280). Conclusion: Despite higher immediate post-operative complications in pl-DMEK, long-term clinical outcomes remain comparable or better than pc-UT-DSAEK grafts. Eye bank prepared grafts are therefore safe and reliable for challenging EK procedures
Double trouble in DMEK surgery: Learning experience and review of the literature
No full textPurpose: To report a challenging Descemet Membrane Endothelial Keratoplasty (DMEK) case, complicated by intraoperative aqueous misdirection and spontaneous anterior chamber fibrin reaction. Methods: A 70-year-old female affected by corneal edema due to Fuchs endothelial dystrophy underwent a triple procedure (cataract extraction - IOL implantation - DMEK surgery) in her left eye. This report illustrates the management of the intraoperative complications of aqueous misdirection syndrome and anterior chamber fibrin reaction. Results: Despite the optimal management of the posterior pressure and the thorough removal of the fibrinous reaction during the case, the DMEK graft was not completely unfolded and centred at the end of the surgical procedure. Nonetheless, the patient showed good long-term anatomical and functional recovery: at the last follow-up (2 years after surgery), central corneal thickness was 526 μm with a best corrected visual acuity of 20/25 and an endothelial cell density of 1112 cell/mm2. Conclusion: Early recognition and prompt management of intraoperative aqueous misdirection syndrome and anterior chamber fibrin reaction during DMEK surgery is essential to ensure good functional and anatomical outcomes
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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