Nano-alumina powders/ceramics derived from aluminum foil waste at low temperature for various industrial applications.

In this work, nanoscale single crystalline γ- and α-alumina powders have been successfully prepared from aluminum foil waste precursor via co-precipitation method using NH4OH as a precipitant. The obtained gel after co-precipitation treatment, was calcined at different temperatures (500,700, 900, 1050, 1100, 1300 and 1500 °C) and the products were characterized by XRD, FTIR and HRTEM. The results revealed that nano-γ-Al2O3 was fully transformed to nanometer-sized α-Al2O3 (36-200 nm) after annealing at temperatures as low as 1100 °C.The thermally preheated powder at 500 °C was further pressed under 95 MPa by the uniaxial press and the obtained bodies were found to have98.82% of the theoretical density, 1.18% porosity and 708 MPa compressive strength, when sintered at temperatures as low as 1600 °C without using any sintering aid. These excellent results proved that this work will contribute to finding a commercial source for preparing sub 100 nm α-alumina through the secondary resources management and even more so to synthesizing strong α-Al2O3 bodies which are promising in terms of their structure and compression. The α-Al2O3 bodies synthesized by the present work could be used as a feedstock for fabrication of various kinds of functional and structural materials that are extensively used in high tech.

Maximize the use of municipal waste generated by the hydrogen peroxide industry in the production of high-quality refractory CAC.

High-grade calcium aluminate cement (CAC) has been successfully synthesized from municipal alumina waste and limestone under mild reaction conditions. Mineralogical composition and microstructure of the sintered mixes were investigated using X-ray diffraction and FESEM; valuable cementing phases such as CA, CA2, and C12A7 were observed in addition to the C3A phase that was detected in the mixes with high CaCO3 content. Mix CA60 containing 60 wt% alumina waste has achieved the best sinterability (less than 1 vol% porosity) and the highest densification (~ 2.65 g/cm3 bulk density) at 1450 °C. Densification, cold-crushing strength (CCS), and microstructure of the hydrated cement samples (From Mix CA60) were investigated. The cast cement specimens revealed better density and CCS characteristics (63.1 and 74 MPa at 7 and 28 days, respectively) in comparison with the commercial cement. Conventional castables (5 × 5 × 5 cm3) were prepared from mixtures composed of 15 wt% cement and 85 wt% aggregates (40% Al2O3), where CA60 and commercial cement were used to compare the effect of the manufactured CA60 cement with the commercial one. The castables prepared with CA60 cement have shown a higher strength at 110 °C with 4.5 MPa when compared to the commercial CAC at the same temperature (1.8 MPa). Accordingly, this study contributes not only to preserving the environment from the accumulation of industrial wastes but also to valorizing and adding value to these wastes.

Considerations for using Natalizumab treatment in patients with a history of choroidal melanoma.

Natalizumab is a monoclonal antibody licensed for the treatment of relapsing-remitting multiple sclerosis (RRMS). It is known to increase the potential risk of developing progressive multifocal leukoencephalopathy (PML). There is current debate in the literature regarding its association with malignant melanoma. Herein, we report a case of a 55-year old lady with RRMS for whom natalizumab therapy was being considered by her neurologist. Her medical history included a choroidal melanoma which had undergone successful treatment. Additionally, in this case study we discuss the issues regarding malignant melanoma risk and recurrence with natalizumab treatment.

Repair of macular fold following retinal reattachment surgery.

Here the management of a macular fold complicating retinal reattachment surgery is discussed. The macular fold was repaired by a technique similar to that used in retinal translocation surgery. Direct injection into the macular fold was performed, which caused a linear, rather than the intended concentric, detachment of the retina. Permanent flattening of the macula fold was achieved and the best-corrected Snellen visual acuity was 6/12 at 6 months. The importance of intervention, advantages and disadvantages of this technique and alternative methods of managing such cases are discussed. It may be prudent to consider peripheral, rather than direct, injection into the macular fold to detach the macula in such cases.

WIDESPREAD MACULAR NEUROSENSORY DETACHMENT AFTER OCRIPLASMIN INTRAVITREAL INJECTION.

PURPOSE: To present the case of a patient with vitreomacular traction who experienced immediate severe acute complications after ocriplasmin intravitreal injection. METHODS: Case report. RESULTS: A 61-year-old woman with vitreomacular traction underwent ocriplasmin treatment. Within 24 hours after injection, she noticed severe reduction in visual acuity. Spectral domain optical coherence tomography revealed release of vitreous traction, together with widespread subretinal fluid and decreased reflectivity in the outer retina. Ten weeks after treatment, visual acuity improved, although below pretreatment levels, with partial reduction in subretinal fluid. CONCLUSION: Intravitreal ocriplasmin can produce acute visual acuity changes with widespread subretinal fluid and outer retinal ellipsoid zone hyporeflectivity on spectral domain optical coherence tomography. The overall acute and long-term safety profile of ocriplasmin remains unknown.

Safety testing of infracyanine green using retinal pigment epithelium and glial cell cultures.

PURPOSE: To undertake safety testing of infracyanine green (IFCG) in a cell culture model. METHODS: Experiments were undertaken in a cell culture model used previously to perform safety testing of indocyanine green (ICG). Human retinal pigment epithelium (RPE) and Müller cells were exposed to IFCG for 5 minutes, over a range of concentrations up to 0.5%. Experiments were repeated, using double-staining with trypan blue. Cell viability was measured at days 1, 5, and 15 using a mitochondrial dehydrogenase assay and a fluorescent live-dead probe containing calcein and ethidium homodimer-1. Viability was measured after exposure to 0.5% IFCG and 5 minutes of illumination with a vitrectomy endolight powered by a xenon light source. RESULTS: RPE viability was not reduced over the range of concentrations and follow-up intervals. RPE cells exposed to IFCG and illumination had reduced viability relative to the negative control (cells exposed to saline), but not relative to those exposed to saline and illumination. Glial cells showed reduced viability at days 1 and 5, but not day 15. Illumination did not further reduce viability. CONCLUSIONS: IFCG has been advocated as a safer macular vital stain than ICG. These results suggest that it is less likely to produce phototoxicity, but despite being nearly iso-osmolar, IFCG also produces damage in cultured glial cells.

Pattern ERG correlates of abnormal fundus autofluorescence in patients with retinitis pigmentosa and normal visual acuity.

PURPOSE: To examine the functional significance of central abnormalities present in fundus autofluorescence (AF) images in patients with rod-cone dystrophy and good visual acuity. METHODS: Thirty patients were selected according to three criteria: a clinical diagnosis of retinitis pigmentosa (RP) confirmed with International Society for Clinical Electrophysiology of Vision (ISCEV) standard ERGs, a parafoveal ring of increased high density on fundus AF imaging, and a visual acuity of 20/30 or better. Macular function was assessed with pattern electroretinography (PERG) to checkerboard stimuli of different field sizes. Fundus AF imaging was performed with a confocal scanning laser ophthalmoscope. RESULTS: The radius of the parafoveal ring of high density varied between 1.5 degrees and 9 degrees. The PERG P50 amplitude correlated highly with the radius of the ring of increased autofluorescence (r = 0.80, P < 0.0005, n = 30). PERGs to smaller circular field sizes were present, but increasing field size to beyond that of the high-density autofluorescence ring did not produce further increases in P50 amplitude. There was a high correlation between the minimum stimulus size required to elicit a maximum-amplitude PERG and the radius of the ring (r = 0.87). CONCLUSIONS: The high correlation between AF imaging and PERG, an established technique in the assessment of central retinal function, demonstrates the likelihood that autofluorescence abnormalities have functional significance and may therefore be a valuable additional parameter in the monitoring of these patients.

Combined hamartoma of the retina and retinal pigment epithelium.

We report two cases of combined hamatoma of the retina and retinal pigment epithelium (CHR-RPE), illustrated with ultrasonography, optical coherence tomography, fundus fluorescein angiography and indocyanine green angiography images. CHR-RPE could clinically mimic several other retinal conditions. Failure to distinguish it from serious malignancies such as choroidal melanoma or retinoblastoma has led to unnecessary enucleation in the past. Through these case reports and a review of literature, we show the diagnostic features of CHR-RPE, its key differential diagnoses and the management options.

Amyloid-beta peptide is toxic to neurons in vivo via indirect mechanisms.

We have studied the neurotoxicity of amyloid-beta (Abeta) after a single unilateral intravitreal injection. Within the retina apoptotic cells were seen throughout the photoreceptor layer and the inner nuclear layer but not in the ganglion cell layer at 48 h after injection of Abeta(1-42) compared to vehicle control and control peptide. At 5 months, there was a significant reduction in total cell numbers in the ganglion cell layer in Nissl stained retinas. There was glial cell dysfunction with upregulation of glial fibrillary acidic protein and a reduction in the expression of Müller cell associated proteins in the injected retinas. These results suggest an indirect cytotoxic effect of Abeta on retinal neurons and an important role for dysfunction of Müller glia in mediating Abeta neurotoxicity.