High temperature heat treatment of B precursor and P.I.T. process optimization to increase Jc performances of MgB2-based conductor

Promising results reported in our previous works led us to think that production of B powder plays a crucial role in MgB2 synthesis. A new method for boron preparation has been developed in our laboratory. This particular process is based on magnesiothermic reaction (Moissan process) with the addition of an initial step that gives boron powder with nano-metric grain size. In this paper we report our efforts regarding optimization of PIT method for these nanometric powders and the resolution of problems previously highlighted such as the difficulty in powder packaging and the high friction phenomena occurring during cold working. This increases cracking during the tape and wire manufacturing leading to its failure. Packaging problems are related to the amorphous nature of boron synthesized in our laboratory, so a crystallization treatment was applied to improve crystallinity of B powder. To prevent excessive friction phenomena we synthesized non-stoichiometric MgB2 and using magnesium as lubricant. Our goal is the Jc improvement, but a global physical-chemical characterization was also made to analyze the improvement given by our treatments: this characterization includes X-ray diffraction, resistivity vs. temperature measurement, SEM image, besides magnetic and transport Jc measurements.Comment: 15 pages, 11 figure

Assessment of Corneal Fluorescein Staining in Different Dry Eye Subtypes Using Digital Image Analysis

To describe a new objective technique of digital image analysis for the quantification and the morphological characterization of corneal staining in the setting of dry eye disease (DED), and to apply it to distinguish Sj\uf6gren syndrome (SS) from ocular graft versus-host disease (oGVHD)

Grain size determination of superconducting MgB2 powders from magnetization curve, image analysis and surface area measurement

The present article reports a method for the average grain size evaluation of superconducting nano-particles through their magnetic properties. The use of SQUID magnetometry to determine the average MgB2 particle size was investigated and the results compared with those achieved through other techniques. In particular the data obtained from zero field cooled magnetization measurement as function of the temperature were compared with the results obtained by scanning electron microscopy and Brunauer-Emmett-Teller techniques. The particle magnetization was measured by a commercial SQUID magnetometer in magnetic field (1 mT) and temperatures ranging from 5 to 50 K dispersing the powders in a grease medium. The grain size is obtained by fitting the data taking into account the Ginzburg-Landau temperature dependence of the London penetration depth. Variations on typical modeling parameters were explored in order to gain a better picture of the average grain size and the effectiveness of various measurement techniques. We find that it is possible to use the magnetization measurements to determine the average grain size even if the SEM image analysis allows extracting more information about the grain size distribution. Furthermore a Matlab routine has been developed in order to get automatic analysis of SEM images.Comment: 12 pages, 10 figures, 5 table

Astigmatism Orientation After Deep Anterior Lamellar Keratoplasty for Keratoconus and Its Correlation With Preoperative Peripheral Corneal Astigmatism

To evaluate the orientation of keratometric astigmatism (KA) after deep anterior lamellar keratoplasty (DALK) for keratoconus and its correlation with preoperative peripheral KA

Autologous Descemet Stripping Automated Endothelial Keratoplasty to Eliminate Endothelial Rejection in Eyes at High Risk

To determine whether autologous Descemet stripping endothelial keratoplasty is technically feasible and whether it eliminates the risk of endothelial rejection in "only eyes" at high risk of immunological rejection

A novel blunt dissection technique to treat modified deep anterior lamellar keratoplasty (DALK)-associated high astigmatism

To describe a new surgical technique to correct a high astigmatism following modified deep anterior lamellar keratoplasty (DALK) and to evaluate the associated clinical outcomes

Manufacturing process influence on superconducting properties of MgB<inf>2</inf> wires prepared using laboratory made boron

none5noBovone, Gianmarco; Matera, Davide; Bernini, Cristina; Magi, Emanuele; Vignolo, MaurizioBovone, Gianmarco; Matera, Davide; Bernini, Cristina; Magi, Emanuele; Vignolo, Maurizi

Deep Anterior Lamellar Keratoplasty: Current Status and Future Directions

Abstract: Deep anterior lamellar keratoplasty (DALK) involves selective replacement of diseased corneal stroma while preserving normal healthy endothelium. Despite several well-recognized advantages, the uptake of DALK has remained sluggish with an adoption rate that has plateaued over the past decade. Misconceptions such as the rarity of complications of penetrating keratoplasty, lack of standardization of the DALK technique, and limited substantial benefit in visual and refractive outcomes are frequently cited as arguments against performing DALK. This brief review discusses the recent findings that refute these perceived barriers; describes contemporary techniques, tools, and modifications in the surgical approach; and evaluates the evidence regarding the clinical outcomes of DALK