2,643 research outputs found

    Bibliometric Analysis of Ophthalmic Journals

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    Importance: The primary vehicle for reporting and testing advances in eye care is refereed ophthalmic journals, which can be characterized using targeted bibliometric analyses. Objective: To identify all ophthalmic journals and evaluate citation metrics relating to articles, journals, authors, institutions, and countries published therein. Design and Setting: A bibliometric analysis was undertaken of all ophthalmic journals included in the Scopus database (Elsevier). The search was restricted to all article types published in ophthalmic journals in English from inception through November 18, 2022. After excluding general medical journals, journals published in a language other than English, and spurious titles unrelated to the ophthalmic field, the Scopus database was found to list 335 ophthalmic journal titles that have published 471184 articles, constituting the data set for this analysis. The 20 most highly cited articles were identified. Rank-order lists by article count were assembled for journals, authors, institutions, and countries. Main Outcomes and Measures: An h-index for ophthalmic journal articles was derived from citations and article counts for each constituent of each category. Results: The h-index for ophthalmic journal articles was determined to be 494. The journal with the highest h-index was Ophthalmology (h-index, 297). The journal with the greatest number of articles was American Journal of Ophthalmology (38441 articles). The most highly cited article was by Quigley and Broman, 2006 (5147 citations), concerning the epidemiology of glaucoma. The author with the highest h-index for ophthalmic journal articles was Ronald Klein, MD (h-index, 126), and the most prolific was Carol L. Shields, MD (1400 articles). Johns Hopkins University (h-index, 215) was the institution with the highest h-index for ophthalmic journal articles, and Harvard University was the most prolific (10071 articles). The United States was the nation with the highest h-index for ophthalmic journal articles (h-index, 444) and was the most prolific (180017 articles). Conclusions and Relevance: In this study, the most highly cited articles published in ophthalmic journals were revealed, as well as the leading journals, authors, institutions, and countries. While excluding ophthalmology articles in general medical journals, this investigation affords a means of identifying highly cited authors, institutions, and countries which individuals or institutions can use as a guide regarding contributions to the field.</p

    Membrane attack complex inhibitor CD59a protects against focal cerebral ischemia in mice

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    <p>Abstract</p> <p>Background</p> <p>The complement system is a crucial mediator of inflammation and cell lysis after cerebral ischemia. However, there is little information about the exact contribution of the membrane attack complex (MAC) and its inhibitor-protein CD59.</p> <p>Methods</p> <p>Transient focal cerebral ischemia was induced by middle cerebral artery occlusion (MCAO) in young male and female CD59a knockout and wild-type mice. Two models of MCAO were applied: 60 min MCAO and 48 h reperfusion, as well as 30 min MCAO and 72 h reperfusion. CD59a knockout animals were compared to wild-type animals in terms of infarct size, edema, neurological deficit, and cell death.</p> <p>Results and Discussion</p> <p>CD59a-deficiency in male mice caused significantly increased infarct volumes and brain swelling when compared to wild-type mice at 72 h after 30 min-occlusion time, whereas no significant difference was observed after 1 h-MCAO. Moreover, CD59a-deficient mice had impaired neurological function when compared to wild-type mice after 30 min MCAO.</p> <p>Conclusion</p> <p>We conclude that CD59a protects against ischemic brain damage, but depending on the gender and the stroke model used.</p

    Temporal variations in meibomian gland structure—A pilot study

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    Purpose: To investigate whether there is a measurable change in meibomian gland morphological characteristics over the course of a day (12h) and over a month.Methods: The study enrolled 15 participants who attended a total of 11 study visits spanning a 5-week period. To assess diurnal changes in meibomian glands, seven visits were conducted on a single day, each 2h apart. For monthly assessment, participants attended an additional visit at the same time of the day every week for three consecutive weeks. Meibography using the LipiViewŸ II system was performed at each visit, and meibomian gland morphological parameters were calculated using custom semi-automated software. Specifically, six central glands were analysed for gland length ratio, gland width, gland area, gland intensity and gland tortuosity.Results: The average meibomian gland morphological metrics did not exhibit significant changes during the course of a day or over a month. Nonetheless, certain individual gland metrics demonstrated notable variation over time, both diurnally and monthly. Specifically, meibomian gland length ratio, area, width and tortuosity exhibited significant changes both diurnally and monthly when assessed on a gland-by-gland basis.Conclusions: Meibomian glands demonstrated measurable structural change over short periods of time (hours and days). These results have implications for innovation in gland imaging and for developing precision monitoring of gland structure to assess meibomian gland  health more accurately

    The Educational Consequences of Teen Childbearing

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    A huge literature shows that teen mothers face a variety of detriments across the life course, including truncated educational attainment. To what extent is this association causal? The estimated effects of teen motherhood on schooling vary widely, ranging from no discernible difference to 2.6 fewer years among teen mothers. The magnitude of educational consequences is therefore uncertain, despite voluminous policy and prevention efforts that rest on the assumption of a negative and presumably causal effect. This study adjudicates between two potential sources of inconsistency in the literature—methodological differences or cohort differences—by using a single, high-quality data source: namely, The National Longitudinal Study of Adolescent Health. We replicate analyses across four different statistical strategies: ordinary least squares regression; propensity score matching; and parametric and semiparametric maximum likelihood estimation. Results demonstrate educational consequences of teen childbearing, with estimated effects between 0.7 and 1.9 fewer years of schooling among teen mothers. We select our preferred estimate (0.7), derived from semiparametric maximum likelihood estimation, on the basis of weighing the strengths and limitations of each approach. Based on the range of estimated effects observed in our study, we speculate that variable statistical methods are the likely source of inconsistency in the past. We conclude by discussing implications for future research and policy, and recommend that future studies employ a similar multimethod approach to evaluate findings

    A Search for Wolf-Rayet Stars in the Small Magellanic Cloud

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    We conducted an extensive search for Wolf-Rayet stars (W-Rs) in the SMC, using the same interference filter imaging techniques that have proved successful in finding W-Rs in more distant members of the Local Group. Photometry of some 1.6 million stellar images resulted in some 20 good candidates, which we then examined spectroscopically. Two of these indeed proved to be newly found W-Rs, bringing the total known in the SMC from 9 to 11. Other finds included previously unknown Of-type stars (one as early as O5f?p)),the recovery of the Luminous Blue Variable S18, and the discovery of a previously unknown SMC symbiotic star. More important, however, is the fact that there does not exist a significant number of W-Rs waiting to be discovered in the SMC. The number of W-Rs in the SMC is a factor of 3 lower than in the LMC (per unit luminosity), and we argue this is the result of the SMC's low metallicity on the evolution of the most massive stars.Comment: Accepted by Astrophysical Journal. Postscript version available via ftp.lowell.edu/pub/massey/smcwr.ps.gz Revised version contains slightly revised spectral types for the Of stars but is otherwise unchange

    Novel switching mode in a vertically aligned liquid crystal contact lens

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    Liquid crystal (LC) contact lenses are emerging as an exciting technology for vision correction. A homeotropically (vertical) aligned LC lens is reported that offers improved optical quality and simplified construction techniques over previously reported LC contact lens designs. The lens has no polarization dependence in the off state and produces a continuous change in optical power of up to 2.00 ± 0.25 D with a voltage applied. The variation in optical power results from the voltage-induced change in refractive index of the nematic LC layer, from 1.52 to a maximum of 1.72. One device substrate is treated with an alignment layer that is a mixture of planar and homeotropic polyimides, rubbed to induce a preferred director orientation in the switched state. Defects that could occur during switching are thus avoided and the lens exhibits excellent optical quality with a continuous variation in focal power

    Are lay people good at recognising the symptoms of schizophrenia?

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    ©2013 Erritty, Wydell. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.This article has been made available through the Brunel Open Access Publishing Fund.Aim: The aim of this study was to explore the general public’s perception of schizophrenia symptoms and the need to seekhelp for symptoms. The recognition (or ‘labelling’) of schizophrenia symptoms, help-seeking behaviours and public awareness of schizophrenia have been suggested as potentially important factors relating to untreated psychosis. Method: Participants were asked to rate to what extent they believe vignettes describing classic symptoms (positive and negative) of schizophrenia indicate mental illness. They were also asked if the individuals depicted in the vignettes required help or treatment and asked to suggest what kind of help or treatment. Results: Only three positive symptoms (i.e., Hallucinatory behaviour, Unusual thought content and Suspiciousness) of schizophrenia were reasonably well perceived (above 70%) as indicating mental illness more than the other positive or negative symptoms. Even when the participants recognised that the symptoms indicated mental illness, not everyone recommended professional help. Conclusion: There may be a need to improve public awareness of schizophrenia and psychosis symptoms, particularly regarding an awareness of the importance of early intervention for psychosis
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