RESUMO
Nanoparticles having particle size in the range 25-40 nm for compositions x = 0.0, 0.2, 0.4 and 0.5 of Mg(x)Mn(1-x)Fe2O4 spinel ferrite system have been prepared by chemical co-precipitation route. The microstructure, infrared spectral and elastic properties have been studied by means of energy dispersive analysis of X-rays (EDAX), transmission electron microscopy (TEM), X-ray diffraction (XRD) and infrared spectroscopic (IR) measurements, before (W) and after high temperature annealing A(w). The force constants for tetrahedral and octahedral sites determined by infrared spectral analysis, lattice constant and X-ray density values by X-ray diffraction pattern analysis; have been used to calculate elastic constants. The magnitude of force constant and elastic moduli for nanocrystalline W-samples are found to be larger as compared to coarse grained A(w)-samples. The results have been explained in the light of redistribution of cations and as a result change in mean ionic charge for such cationic sites, elastic energy and grain size reduction effect of Nanoparticles.
RESUMO
Tuberous sclerosis is a rare neuro-cutaneous syndrome with autosomal dominant penetrance. Only some organs are involved, e.g., skin (earthy skin thickenings, ash leaf patches), cerebral cortex (hamartomatous nodules) and kidneys, (angiolipoma, adenocarcinoma). These hamar-tomatous swellings resemble potatoes and hence, referred to as tubers. We herein report on three patients (all familial), father, son and granddaughter, with this rare involvement, from the eastern part of India. The father and son had involvement of only the skin (i.e. nose) and kidneys while the disease penetrated further in the subsequent filial generations with son and granddaughter having skin, brain and bilateral kidney involvement. This kind of tri-filial progression has not till date, been reported from this region, making it an interesting case presentation.