3,754 research outputs found
Side Effects of Brolucizumab
Age-related macular degeneration and its complication, subretinal neovascularization, are common causes of progressive, irreversible impairment of central vision. Antivascular endothelial growth factor (anti-VEGF) therapy has improved the visual outcome and provided an evolution in the treatment of retinal disease. The current four anti- VEGF drugs â pegaptanib, ranibizumab, aflibercept, and bevacizumab â have been administered for many years. A new anti-VEGF agent, brolucizumab, was approved by the U.S. Food and Drug Administration (FDA) in late 2019 for the treatment of wet agerelated macular degeneration. Brolucizumab is a novel single-chain fragment variable antibody that inhibits all isoforms of VEGF-A and has been suggested to have more tissue penetration. Despite all the benefits, there are some reports of serious side effects that need to be understood in managing patients. Brolucizumab has been reported to cause occlusive retinal vasculitis in the setting of intraocular inflammation, which has not been seen in other anti-VEGF medications. A PubMed and Scopus search was performed and all article types were included. In the present article, we have reviewed the reported side effects of brolucizumab
Diffuse reflectance imaging with astronomical applications
Diffuse objects generally tell us little about the surrounding lighting, since the radiance they reflect blurs together incident lighting from many directions. In this paper we discuss how occlusion geometry can help invert diffuse reflectance to recover lighting or surface albedo. Self-occlusion in the scene can be regarded as a form of coding, creating high frequencies that improve the conditioning of diffuse light transport. Our analysis builds on a basic observation that diffuse reflectors with sufficiently detailed geometry can fully resolve the incident lighting. Using a Bayesian framework, we propose a novel reconstruction method based on high-resolution photography, taking advantage of visibility changes near occlusion boundaries. We also explore the limits of single-pixel observations as the diffuse reflector (and potentially the lighting) vary over time. Diffuse reflectance imaging is particularly relevant for astronomy applications, where diffuse reflectors arise naturally but the incident lighting and camera position cannot be controlled. To test our approaches, we first study the feasibility of using the moon as a diffuse reflector to observe the earth as seen from space. Next we present a reconstruction of Mars using historical photometry measurements not previously used for this purpose. As our results suggest, diffuse reflectance imaging expands our notion of what can qualify as a camera.Natural Sciences and Engineering Research Council of Canada (NSERC) (Postdoctoral Fellowship)United States-Israel Binational Science Foundation (Grant 2008155)United States. National Geospatial-Intelligence Agency (NEGI-1582-04-0004)United States. Multidisciplinary University Research Initiative (Grant N00014-06-1-0734
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In Vivo Photovoltaic Performance of a Silicon Nanowire Photodiode-Based Retinal Prosthesis.
Purpose:For more than 20 years, there has been an international, multidisciplinary effort to develop retinal prostheses to restore functional vision to patients blinded by retinal degeneration. We developed a novel subretinal prosthesis with 1512 optically addressed silicon nanowire photodiodes, which transduce incident light into an electrical stimulation of the remaining retinal circuitry. This study was conducted to evaluate the efficacy of optically driving the subretinal prosthesis to produce visual cortex activation via electrical stimulation of the retina. Methods:We measured electrically evoked potential responses (EEPs) in rabbit visual cortex in response to illumination of the subretinal nanowire prosthesis with pulsed 852-nm infrared (IR) light. We compared the EEP responses to visually evoked potential responses (VEPs) to pulsed 532-nm visible light (positive control) and pulsed 852-nm IR light (negative control). Results:Activating the devices with IR light produced EEP responses with a significantly higher trough-to-peak amplitude (54.17 ± 33.4 ΌV) than IR light alone (24.07 ± 22.1 ΌV) or background cortical activity (23.22 ± 17.2 ΌV). EEP latencies were significantly faster than focal VEP latencies. Focal VEPs produced significantly higher amplitudes (94.88 ± 43.3 ΌV) than EEPs. We also demonstrated how an electrode placed on the cornea can be used as a noninvasive method to monitor the function of the implant. Conclusions:These results show that subretinal electrical stimulation with nanowire electrodes can elicit EEPs in the visual cortex, providing evidence for the viability of a subretinal nanowire prosthetic approach for vision restoration
Stakeholder Theory and Marketing: Moving from a Firm-Centric to a Societal Perspective
This essay is inspired by the ideas and research examined in the special section on âStakeholder Marketingâ of the Journal of Public Policy & Marketing in 2010. The authors argue that stakeholder marketing is slowly coalescing with the broader thinking that has occurred in the stakeholder management and ethics literature streams during the past quarter century. However, the predominant view of stakeholders that many marketers advocate is still primarily pragmatic and company centric. The position advanced herein is that stronger forms of stakeholder marketing that reflect more normative, macro/societal, and network-focused orientations are necessary. The authors briefly explain and justify these characteristics in the context of the growing âprosocietyâ and âproenvironmentâ perspectivesâorientations that are also in keeping with the public policy focus of this journal. Under the âhard formâ of stakeholder theory, which the authors endorse, marketing managers must realize that serving stakeholders sometimes requires sacrificing maximum profits to mitigate outcomes that would inflict major damage on other stakeholders, especially society
Ultraviolet Emission Lines in Young Low Mass Galaxies at z~2: Physical Properties and Implications for Studies at z>7
We present deep spectroscopy of 17 very low mass (M* ~ 2.0x10^6 Msun to
1.4x10^9 Msun) and low luminosity (M_UV ~ -13.7 to -19.9) gravitationally
lensed galaxies in the redshift range z~1.5-3.0. Deep rest-frame ultraviolet
spectra reveal large equivalent width emission from numerous lines (NIV],
OIII], CIV, Si III], CIII]) which are rarely seen in individual spectra of more
massive star forming galaxies. CIII] is detected in 16 of 17 low mass star
forming systems with rest-frame equivalent widths as large as 13.5 Angstroms.
Nebular CIV emission is present in the most extreme CIII] emitters, requiring
an ionizing source capable of producing a substantial component of photons with
energies in excess of 47.9 eV. Photoionization models support a picture whereby
the large equivalent widths are driven by the increased electron temperature
and enhanced ionizing output arising from metal poor gas and stars, young
stellar populations, and large ionization parameters. The young ages implied by
the emission lines and continuum SEDs indicate that the extreme line emitters
in our sample are in the midst of a significant upturn in their star formation
activity. The low stellar masses, blue UV colors, and large sSFRs of our sample
are similar to those of typical z>6 galaxies. Given the strong attenuation of
Ly-alpha in z>6 galaxies we suggest that CIII] is likely to provide our best
probe of early star forming galaxies with ground-based spectrographs and one of
the most efficient means of confirming z>10 galaxies with the James Webb Space
Telescope.Comment: 22 pages, 8 figures, accepted for publication in MNRA
Looking for imprints of the first stellar generations in metal-poor bulge field stars
© 2016 ESO. Context. Efforts to look for signatures of the first stars have concentrated on metal-poor halo objects. However, the low end of the bulge metallicity distribution has been shown to host some of the oldest objects in the Milky Way and hence this Galactic component potentially offers interesting targets to look at imprints of the first stellar generations. As a pilot project, we selected bulge field stars already identified in the ARGOS survey as having [Fe/H] 1 and oversolar [α/Fe] ratios, and we used FLAMES-UVES to obtain detailed abundances of key elements that are believed to reveal imprints of the first stellar generations. Aims. The main purpose of this study is to analyse selected ARGOS stars using new high-resolution (R ⌠45 000) and high-signal-tonoise (S=N > 100) spectra. We aim to derive their stellar parameters and elemental ratios, in particular the abundances of C, N, the α-elements O, Mg, Si, Ca, and Ti, the odd-Z elements Na and Al, the neutron-capture s-process dominated elements Y, Zr, La, and Ba, and the r-element Eu. Methods. High-resolution spectra of five field giant stars were obtained at the 8 m VLT UT2-Kueyen telescope with the UVES spectrograph in FLAMES-UVES configuration. Spectroscopic parameters were derived based on the excitation and ionization equilibrium of Fe i and Fe ii. The abundance analysis was performed with a MARCS LTE spherical model atmosphere grid and the Turbospectrum spectrum synthesis code. Results.We confirm that the analysed stars are moderately metal-poor (-1:04â€[Fe/H]â€-0:43), non-carbon-enhanced (non-CEMP) with [C/Fe] â€+0:2, and α-enhanced.We find that our three most metal-poor stars are nitrogen enhanced. The α-enhancement suggests that these stars were formed from a gas enriched by core-collapse supernovae, and that the values are in agreement with results in the literature for bulge stars in the same metallicity range. No abundance anomalies (Na-O, Al-O, Al-Mg anti-correlations) were detected in our sample. The heavy elements Y, Zr, Ba, La, and Eu also exhibit oversolar abundances. Three out of the five stars analysed here show slightly enhanced [Y/Ba] ratios similar to those found in other metal-poor bulge globular clusters (NGC 6522 and M 62). Conclusions. This sample shows enhancement in the first-to-second peak abundance ratios of heavy elements, as well as dominantly s-process element excesses. This can be explained by different nucleosynthesis scenarios: (a) the main r-process plus extra mechanisms, such as the weak r-process; (b) mass transfer from asymptotic giant branch stars in binary systems; (c) an early generation of fast-rotating massive stars. Larger samples of moderately metal-poor bulge stars, with detailed chemical abundances, are needed to better constrain the source of dominantly s-process elements in the early Universe
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