Serum cortisol and adrenocorticotrophic hormone (ACTH) in infants receiving topical and subconjunctival corticosteroids following cataract surgery.

PURPOSE: Cushingoid features are occasionally encountered in infants after pediatric cataract surgery. The aim of this study is to evaluate whether the use of topical glucocorticoids (GCs) following congenital cataract surgery can result in endogenous adrenal suppression and/or systemic side effects similar to those seen with systemic steroids. METHODS: A prospective study was performed on 20 infants with bilateral congenital cataract. All infants received a single subconjunctival betamethasone injection of 1 mg at the end of surgery in addition to topical dexamethasone eye drops 1 mg/ml for 6 weeks. All infants had anthropometric measurements and blood pressure measurements, serum cortisol, and ACTH level measurements before surgery and 2 months after. In addition, the total administered glucocorticoid adjusted per weight was calculated. RESULTS: The mean age of the infants was 4.93 ± 2.58 months. Thirteen were males (65%). The total administered glucocorticoid dose was 18.7 mg and the mean cumulative dexamethasone equivalent dose administered was 2.75 ± 1.31 mg/kg. There was a statistically significant increase in the adjusted weight percentile for age (P = 0.009). Both the systolic and diastolic blood pressure were significantly elevated (P = 0.005 and P = 0.025 respectively). There was a statistically significant reduction in both the morning and afternoon serum ACTH levels (P = 0.023 and P = 0.014). The reduction in serum cortisol levels was statistically non-significant. CONCLUSIONS: Topical steroids following pediatric cataract surgery can result in both subclinical and clinical changes in the hypothalamic-pituitary-adrenal axis that can be easily overlooked and need careful attention and follow-up.

Half-metallicity in new Heusler alloys Mn2ScZ (Z = Si, Ge, Sn).

Study of half-metallicity has been performed in a new series of Mn2ScZ (Z = Si, Ge and Sn) full Heusler alloys using density functional theory with the calculation and implementation of a Hubbard correction term (U). Volume optimization in magnetic and non-magnetic phases for both the Cu2MnAl and Hg2CuTi type structures was done to predict the stable ground state configuration. The stability was determined by calculating their formation energy as well as from elastic constants under ambient conditions. A half-metal is predicted for Mn2ScSi and Mn2ScGe with a narrow band gap in the minority spin whereas Mn2ScSn shows a metallic nature. The magnetic moments of Mn and Sc are coupled in opposite directions with different strengths indicating that the ferrimagnetic order and the total magnetic moment per formula unit for half-metals follows the Slater Pauling rule. And a strong effect was shown by the size of the Z element in the electronic and magnetic properties.

Study of half metallicity, structural and mechanical properties in inverse Heusler alloy Mn2ZnSi(1-x)Ge x and a superlattice.

The electronic and magnetic properties of Mn2ZnSi(1-x)Ge x (x = 0.0, 0.125, 0.25, 0.375, 0.5, 0.625, 0.75, 0.875, and 1.0) inverse Heusler alloys and Mn2ZnSi/Mn2ZnGe superlattice have been investigated using first-principles calculations. All these alloys are stable in the fcc magnetic phase and satisfies the mechanical and thermal stability conditions as determined from the elastic constants and negative formation energy. The spin-polarized electronic band structures and the density of states indicate half-metallicity with 100% spin polarization at the Fermi energy level for x = 0.0, 0.125, 0.25, 0.50, and 1.0, with the integral values of the total magnetic moments per formula unit at their equilibrium lattice constants, following the Slater-Pauling rule. The electronic properties and the magnetic moments are mostly contributed by two Mn atoms and are coupled anti-parallel to each other, making them ferrimagnetic in nature. The presence of the half-metallic bandgap with an antiparallel alignment of Mn atoms makes these Heusler alloys a potential candidate for spintronic applications.