Origin of the large dispersion of magnetic properties in nanostructured oxides: FexO/Fe3O4 nanoparticles as a case study

The intimate relationship in transition-metal oxides between stoichiometry and physiochemical properties makes them appealing as tunable materials. These features become exacerbated when dealing with nanostructures. However, due to the complexity of nanoscale materials, establishing a distinct relationship between structure-morphology and functionalities is often complicated. In this regard, in the FexO/Fe3O4 system a largely unexplained broad dispersion of magnetic properties has been observed. Here we show, thanks to a comprehensive multi-technique approach, a clear correlation between magneto-structural properties in large (45 nm) and small (9 nm) FexO/Fe3O4 core/shell nanoparticles that can explain the spread of magnetic behaviors. The results reveal that while the FexO core in the large nanoparticles is antiferromagnetic and has bulk-like stoichiometry and unit-cell parameters, the FexO core in the small particles is highly non-stoichiometric and strained, displaying no significant antiferromagnetism. These results highlight the importance of ample characterization to fully understand the properties of nanostructured metal oxide

Origin of the large dispersion of magnetic properties in nanostructured oxides: FexO/Fe3O4 nanoparticles as a case study

The intimate relationship between stoichiometry and physicochemical properties in transition-metal oxides makes them appealing as tunable materials. These features become exacerbated when dealing with nanostructures. However, due to the complexity of nanoscale materials, establishing a distinct relationship between structure-morphology and functionalities is often complicated. In this regard, in the FexO/Fe3O4 system a largely unexplained broad dispersion of magnetic properties has been observed. Here we show, thanks to a comprehensive multi-technique approach, a clear correlation between the magneto-structural properties in large (45 nm) and small (9 nm) FexO/Fe3O4 core/shell nanoparticles that can explain the spread of magnetic behaviors. The results reveal that while the FexO core in the large nanoparticles is antiferromagnetic and has bulk-like stoichiometry and unit-cell parameters, the FexO core in the small particles is highly non-stoichiometric and strained, displaying no significant antiferromagnetism. These results highlight the importance of ample characterization to fully understand the properties of nanostructured metal oxides

Influence of exchange transfusion on the development of serum immunoglobulins

Thirteen neonates with severe jaundice of various etiologies were followed after exchange transfusion fora period of one year. Blood levels of IgG, IgA, and IgM were measured before and after exchange transfusion, four and ten days later, and at 1, 3, 6, 9, and 12 months of age. Normal and jaundiced but not exchange-transfused infants, matched for age, were used as control subjects. It was concluded that exchange transfusion suppresses the production of autologous IgG and IgA, whereas it provokes IgM synthesis. © 1975

Ascorbic acid malabsorption in thalassaemia

In all groups of thalassaemic children, before loading, the plasma l-ascorbic acid was found invariably lower than in controls. In groups I and II after oral administration of 50 and 100 mg respectively, of ascorbic acid per kg body weight, the plasma l-ascorbic acid level rose significantly less in thalassaemic children than in the controls. Moreover, in group II, after doubling the loading dose (100 mg of ascorbic acid per kg body weight) the increment in plasma l-ascorbic acid level was greater in the controls than in thalassaemic children; also the rate of decrease was delayed in thalassaemic patients up to 6 h. Loading with ascorbic acid intramuscularly (group III), resulted in parallel increase and decrease rates of plasma l-ascorbic acid levels up to the 6th h in the thalassaemic children and in the controls. The above results strongly suggest that in thalassaemia we have to do with ascorbic acid malabsorption. © 1969