We report for the first time the observation of irradiation-induced amorphization of the zirconium suboxide formed during aqueous corrosion of Zr-0.5Nb alloys. High-resolution transmission electron microscopy results reveal amorphization of the hexagonal-ZrO suboxide under heavy ion irradiation at cryogenic temperatures. This irradiation-induced amorphization behaviour is discussed in relation to the arrangement of oxygen interstitials and the formation of stable superlattices. The sensitivity of the suboxide to irradiation damage can lead to phase changes and the accumulation of defects near the oxide/metal interface, which needs to be taken into account in the development of mechanistic models addressing radiation-assisted acceleration of corrosion rates in zirconium alloys.

This ion-irradiation study covers the four major crystal structure types in the Ln(2)TiO(5) series (Ln = lanthanide), namely orthorhombic Pnma, hexagonal P63/mmc, cubic (pyrochlore-like) Fd-3m and cubic (fluorite-like) Fm-3m. This is the first systematic examination of the complete Ln(2)TiO(5) crystal system and the first reported examination of the hexagonal structure. A series of samples, based on the stoichiometry Sm(x)Yb(2-x)TiO5 (where x = 2, 1.4, 1, 0.6, and 0) have been irradiated using 1 MeV Kr2+ ions and characterised in-situ using a transmission electron microscope. Two quantities are used to define ion-irradiation tolerance: critical dose of amorphisation (D-c), which is the irradiating ion dose required for a crystalline to amorphous transition, and the critical temperature (T-c), above which the sample cannot be rendered amorphous by ion irradiation. The structure type plus elements of bonding are correlated to ion-irradiation tolerance. The cubic phases, Yb2TiO5 and Sm0.6Yb1.4TiO5, were found to be the most radiation tolerant, with Tc values of 479 and 697 K respectively. The improved radiation tolerance with a change in symmetry to cubic is consistent with previous studies of similar compounds. (C) 2016 Elsevier B.V. All rights reserved.

Purpose: The goal of this study was to review, evaluate, and perform a meta-analysis on the current literature that reports rates of postoperative endophthalmitis after small gauge transconjunctival sutureless vitrectomy (TSV) and compare it to 20-gauge pars plana vitrectomy (20G PPV).Methods: We performed an extensive review of the current literature. We included only large comparative institutional reviews. Meta-analysis of these reviews was performed.Results: We found six large retrospective comparative cases series on the 25-gauge (25G) TSV as compared to 20G PPV. The test for homogeneity for the meta-analysis indicates that the studies are not homogeneous and therefore the evidence is tentative.Conclusion: We cannot conclude that 25G TSV has a higher rate of postoperative endophthalmitis compared to the 20G PPV. Future retrospective or prospective trials need to take into consideration multiple factors.

While angiogenesis inhibitors are already widely used to treat retinal disease in adults, only limited reports are currently available for the use of anti-VEGF in pediatric vitreoretinal diseases such as retinopathy of prematurity, Coats' disease, familial exudative vitreoretinopathy and retinopathy of incontinentia pigmenti. The limited trials of anti-VEGF therapy for pediatric vitreoretinal diseases are promising, although more extensive controlled trials will be needed to confirm their safety and efficacy. This paper will examine the current evidence for use of anti-VEGF therapy in a number of pediatric vitreoretinal disorders and describe a case of anti-VEGF therapy in retinopathy of incontinentia pigmenti.

The vitreoretinal interface has been identified as the site of many different forms of retinal pathology. The dynamic interaction between the vitreous and the retina has implications for pathology both peripherally and in the posterior pole, in particular, the macula. Before the development of optical coherence tomography (OCT), clinicians relied on astute clinical observation and fundoscopy, fluorescein angiography (FA), and postmortem histology to make assumptions about the role the vitreoretinal interface plays in macular pathology. OCT has given us the ability to view the macula in cross section with resolutions of 1 to 15m and thus has improved our understanding of the following known clinical entities: posterior vitreous detachment (PVD), vitreomacular traction (VMT) syndromes, macular holes, and epiretinal membranes (ERMs). The diagnosis and treatment of these visually indistinct pathologic entities has continued to be a challenge and debated in the literature. A clear understanding of the histopathology of the vitreoretinal interface is useful when treating macular disease. This paper attempts to review the current literature focusing on the histology and ultrastructural pathology of the vitreoretinal interface.

Smith, Stephen R. MD; Kroll, Arnold J. MD; Lou, Peter L. MD; Ryan, Edward A. MD Author Information

von Hippel-Lindau disease is a multisystem familial cancer syndrome that commonly manifests in the eye as retinal capillary hemangiomas. As the earliest manifestation of the disease, these benign hamartomas can lead to secondary visual loss. Their typical clinical characteristics can lead to accurate diagnosis and appropriate treatment with either laser photocoagulation or cryotherapy enhancing one's probability of preserving vision before becoming symptomatic. Accurate diagnosis can also lead to surveillance of the various other organ systems involved in the disease such as the CNS, kidneys, adrenal glands and pancreas. This will also enable the clinician to provide genetic counseling for patients regarding the lifelong manifestations of this disease.

International Ophthalmology Clinics: Fall 2005 - Volume 45 - Issue 4 - p 153-161 doi: 10.1097/01.iio.0000177429.82022.c3

Dense submacular hemorrhage in age-related macular degeneration (ARMD) portends a poor visual prognosis for central vision. There is evidence of direct toxicity from blood products to the photoreceptors. It obscures visualization of the presumed causative choroidal neovascular membrane (CNVM), and resolution of hemorrhage often results in disciform or atrophic scar. With recent advances in vitreoretinal surgical techniques, several approaches to remove subfoveal hemorrhage have been reported. While these methods are successful anatomically in clearing blood, the final visual acuities are not encouraging. This chapter reviews the literature for submacular hemorrhage in ARMD and its natural course and compares the treatment techniques, complications, and results.

Endophthalmitis following routine cataract surgery is a rare but potentially devastating complication resulting in severe vision loss. Various prophylaxis treatments have been tried. However, none have been demonstrated to completely eliminate the risk. The Endophthalmitis Vitrectomy Study (EVS) helped establish clinical guidelines in the treatment of post-operative endophthalmitis in a prospective, randomized, multicenter trial. The strength and limitation of the study will be discussed as well as the current knowledge of the pharmacokinetics of intravitreous injection of antibiotics. Additionally, the common pathologic organisms, the use of antibiotic therapy, steroids, and vitrectomy will be discussed.

Coats’ disease is characterized by retinal vascular abnormalities, hemorrhage, exudation and, in severe cases, secondary retinal detachment. The condition generally presents in the first decade of life, although some cases are diagnosed in adulthood. It is most common in otherwise healthy boys. It makes up one of the more important differential diagnoses of childhood leukocoria, and differentiating it from some forms of ocular malignancy can be difficult.

Uveal effusion syndrome is recognized as abnormal accumulations of proteinaceous fluid in the suprachoroidal and subretinal spaces leading to nonrhegmatogenous retinal detachments and choroidal detachments, It has been reported to be associated with nanophthalmos, in which patients have abnormally thickened sclera.(1) Uveal effusion syndrome also may occur with other conditions (Table 1). There have been few reports of uveal effusion syndrome after surgical procedures, We herein report an unusual case of simultaneous idiopathic bilateral uveal effusions remotely following cataract extractions.

Freilich, Jonathan M. M.D.; Ryan, Edward A. M.D.; Lou, Peter L. M.D.; Kroll, Arnold J. M.D.; Brockhurst, Robert J. M.D.; Harooni, Mark M.D.

Surgical management of macular holes involves removal of tractional prefovial vitreous cortex. Accurately identifying this adherent tissue can potentially decrease intraoperative complications. A new, effective technique using autologous whole blood can be used to identify and facilitate separation of the posterior cortical vitreous.

The HVEM-Tandem User Facility at Argonne National Laboratory interfaces two ion accelerators, a 2 MV tandem accelerator and a 650 kV ion implanter, to a 1.2 MV high-voltage electron microscope. This combination allows experiments involving simultaneous ion irradiation/ion implantation, electron irradiation and electron microscopy/electron diffraction to be performed. In addition the availability of a variety of microscope sample holders permits these as well as other types of in situ experiments to be performed at temperatures ranging from 10 to 1300 K, with the sample in a stressed state or with simultaneous determination of electrical resistivity of the specimen. This article summarizes the details of the Facility which are relevant to simultaneous ion beam material modification and electron microscopy, presents several current applications and briefly describes the straightforward mechanism for potential users to access this US Department of Energy-supported facility.

The HVEM-Tandem National User Facility consists of a modified Kratos/AE1 EM7 HVEM with a maximum accelerating voltage of 1.2 MeV, interfaced to both a 2MV National Electrostatics tandem ion accelerator and a 300 kV Texas Nuclear ion accelerator. The latter is being replaced with a 650 kV National Electrostatics accelerator which should be fully operational in FY 1987. These accelerators provide a wide range of ion species with energies from 25 keV to 8 MeV. The combination of HVEM and ion accelerators provides a truly unique capability for ion irradiation/implantation experimentation along with simultaneous microscopy. The HVEM-Tandem Facility currently is employed for a wide range of materials research, including basic in situ studies of mechanical properties, oxidation and hydrogen effects in metals, radiation effects including ion and electron irradiation-induced phase changes and general defect analysis. More than half of these studies are conducted by non-ANL scientists from universities and other national laboratories. Access to the National User Facility is by means of research proposals which are reviewed by a Steering Committee composed of both Argonne and non-Argonne scientists representing the user community.

Direct observations in the high voltage electron microscope of electron- and ion-beam-induced effects in solids now form a significant part of the research activity at the Argonne National Laboratory High Voltage Electron Microscope Tandem Facility. The programs utilize unique facilities that permit samples held at temperatures between 10 and 1300 K to be bombarded in vacuo with ions having energies between 20 keV and 8 MeV. Instrumentation both internal and external to the high voltage electron microscope has been provided to characterize fully the ion beam at the specimen rod over a wide range of beam intensities.