65 research outputs found

    Nodular Posterior Scleritis: Clinico-Sonographic Characteristics and Proposed Diagnostic Criteria

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    Purpose: To report the clinical and ultrasound features and outcomes of a series of nodular posterior scleritis. / Methods: Retrospective medical record review of 11 consecutive patients with nodular posterior scleritis. Patient demographics, ocular and systemic findings, ultrasound features, and final anatomical and visual outcomes were recorded. / Results: There were 9 females and 2 males (11 eyes) with mean age at presentation of 57 years (range, 30-84 years). Underlying systemic inflammatory disease was present in 73%. Symptoms included pain in 73% and blurred vision in 45%. A solitary amelanotic mass without the presence of lipofuscin was found in all cases. Associated ocular features included retinal pigment epithelial changes (67%), intraocular inflammation (55%), subretinal fluid (50%), macular edema (50%), and choroidal folds (30%). B-mode ultrasound showed a sclerochoroidal mass with high internal reflectivity (100%) of mean elevation of 4.1 mm. There was nodular thickening of the sclera (100%) and fluid in Tenon space or "T" sign (36%). A complete regression of the nodule after the treatment was observed only in 1 patient (11%) and partial regression in 4 patients (44%). / Conclusion: Nodular posterior scleritis should be considered in the differential diagnosis of a single amelanotic choroidal mass showing high internal reflectivity on ultrasound B-scan. It can produce intraocular inflammation in 50% of the cases and may be painless in 25%. It has a high association with a systemic underlying disease

    On the Stereochemistry of the Cations in the Doping Block of Superconducting Copper-Oxides

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    Metal-oxygen complexes containing Cu,- Tl-, Hg-, Bi- and Pb-cations are electronically active in superconducting copper-oxides by stabilizing single phases with enhanced TcT_c, whereas other metal-oxygen complexes deteriorate copper-oxide superconductivity. Cu, Tl, Hg, Bi, Pb in their actual oxidation states are closed shell d10d^{10} or inert s2s^2 pair ions. Their electronic configurations have a strong tendency to polarize the oxygen environment. The closed shell dd ions with low lying nd10nd9(n+1)snd^{10}\leftrightarrow nd^9(n+1)s excitations form linear complexes through dz2sd_{z^2}-s hybridization polarizing the apical oxygens. Comparatively low nd9(n+1)snd^9(n+1)s excitation energies distinguish Cu1+,3+,Tl3+,Hg2+\rm Cu^{1+,3+}, Tl^{3+}, Hg^{2+} from other closed shell d10d^{10} ions deteriorating copper-oxide superconductivity, {\it e.g.} Zn2+\rm Zn^{2+}.Comment: 5 pages, uses REVTEX. To be published in: J. Superconductivity, Proc. Int. Workshop on "Phase Separation, Electronic Inhomogenities and Related Mechanisms for High T_c Superconductors", Erice (Sicily) 9-15 July 199

    Charge density in Cuprite, Cu2O

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    Electron-density distribution of rutile TiO 2

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    Charge density in cuprite, Cu 2

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    Charge Density in Rutile, TiO2

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