Effect of pressure on the superconducting Tc of MgB2

Measurements of the superconducting transition temperature Tc have been performed by the inductive method on MgB2 at pressures up to 28 GPa. Tc decreases with applied pressure, exhibiting a cusp at about 9 GPa. We interpret the appearance of this anomaly in the Tc(P) dependence as a result of the pressure-induced electronic transition. Recent band-structure calculations for MgB2 give some support for such an explanation.Comment: 11 pages, including 4 figure

Prolonged use of selective immunosuppressants in glacoma drainage surgery: experimental in vivo study

V.N. Germanova1,2, E.V. Karlova1,2, L.T. Volova1, N.N. Sarbaeva3, I.F. Nefedova1, M.V. Radaykina2 1Samara State Medical University, Samara, Russian Federation 2Eroshevskiy Eye Hospital, Samara, Russian Federation 3REAVIZ Medical University, Samara, Russian Federation Background: anti-inflammatory and antiproliferative agents are among tools to prevent postoperative scarring. Prolonged use of immunosuppressants characterized by a selective mechanism of action immediately at the surgical site. Aim: to assess the safety and efficacy of bio-resorptive drainage devices enriched with cyclosporine or everolimus in vivo. Patients and Methods: the study was conducted on 52 rabbit eyes. Before to the study, ocular surface disease provoked by the long-term use of preservative-containing IOP-lowering medications was simulated. The next step was the penetrating surgical procedure. The surgery involved implanting bio-resorptive drainage devices of polylactide enriched with cyclosporine or everolimus or control devices (neither cyclosporine nor everolimus). Postoperatively, all rabbits underwent regular ophthalmic exams and IOP measurements. Follow-up was 6 months. After 7&nbsp;days, 1 month, and 6 months, the animals were slaughtered for the histology of surgical site. Results: better characteristics of filtering blebs and lower IOP values were seen among the animals who underwent surgical procedures with immunosuppressants compared to the control group even in the early post-op period. After 1 month, control filtering blebs stopped functioning and were characterized by the IBAGS H0&nbsp; (height) and E0 (extent) in most animals. Meanwhile, in cyclosporine and everolimus groups, filtering blebs were characterized by the IBAGS Н1-Н2 and Е1-Е3 till the end of follow-up. After 6 months, mean IOP was 17.3±0.5 mm Hg in the control group and 13.0±0.4 mm Hg and 11.8±0.6 mm Hg in cyclosporine group and everolimus group, respectively. No significant differences between the groups were reported in terms of complications. Histology matched clinical data and illustrated the mechanism of&nbsp;increased outflow facility after the implantation of drainage devices enriched with immunosuppressants. Conclusion: in vivo experiment has demonstrated higher efficacy and similar safety of IOP-lowering surgery after the implantation of&nbsp;drainage devices enriched with selective immunosuppressants. Keywords: glaucoma surgery, immunosuppressants, cyclosporine, everolimus, drainage device, scarring, filtering bleb. For citation: Germanova V.N., Karlova E.V., Volova L.T. et al. Prolonged use of selective immunosuppressants in glacoma drainage surgery: experimental in vivo study. Russian Journal of Clinical Ophthalmology. 2021;21(2):78–85. DOI: 10.32364/2311-7729-2021-21-2-78-85. <br