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

Assessment of the in vitro antithrombotic properties of sardine (Sardina pilchardus) fillet lipids and cod liver oil

The aim of the current study was to compare the biological activities of total polar lipids (TPL) and thin-layer chromatography (TLC) polar lipid fractions of sardine fillet and cod liver oil against atherogenesis. TPL and TLC polar lipid fractions obtained from these two sources were assessed for their ability to inhibit the platelet-activating-factor (PAF)-induced platelet aggregation (PAF-antagonists) or to induce platelet aggregation (PAF-agonists), since PAF plays a crucial role in the initiation and development of atherosclerosis. This study focused on the polar lipids since previous studies have underlined that the antithrombotic properties of foodstuffs are mainly attributed to polar lipid micro-constituents. TPL of sardine fillet induced platelet aggregation, while TPL of cod liver had a bimodal effect on platelets. TLC polar lipid fractions of both samples exhibited in vitro aggregatory and inhibitory activity towards platelets. However, TLC sardine polar lipid fractions showed stronger in vitro antithrombotic activities than the cod liver oil ones. These data constitute evidence of the putative contribution of fish polar lipids against cardiovascular diseases, underling firstly the beneficial effect of fish and fish lipids as functional foodstuffs against atherogenesis and secondly the more important role of sardine polar lipids as opposed to cod liver oil. © 2015 by the authors; licensee MDPI, Basel, Switzerland

Injectability of silicone oil-based tamponade agents

Background/aims: High viscosity silicone oils are used as tamponade agents to increase the resistance to emulsification; however, this makes the oils more difficult to inject. Increasing the extensional viscosity is one way to reduce emulsification. This study aimed to evaluate how silicone oils with increased extensional viscosity behave in terms of their ease of injection. Methods: The shear viscosity and the length of time taken to inject 9 ml of Siluron 1000, Siluron 2000, Siluron 5000, SiliconMate, a 56/44 w/w blend of Siluron 1000/ Siluron 5000 (Blend A) and a 90/10 w/w blend of Siluron 1000/PDMS 423kDa molecular weight (Blend B) were examined. Results: The shear viscosity of Siluron 1000, Siluron 2000 and Siluron 5000 were within the expected ranges. The shear viscosity of Blend A was 2283 mPa s, Blend B was 4710 mPa s and SiliconMate was 995.3 mPa s. Siluron 1000 and SiliconMate had the shortest injection times as expected due to their lower shear viscosities. Comparison of Siluron 2000 and Blend A demonstrated that Siluron 2000 was easier to inject. Similarly, Blend B was easier to inject than Siluron 5000. Conclusion: Silicone oil blends containing small percentages of a high molecular weight additive are easier to inject than single grade oils of the equivalent shear viscosity.link_to_subscribed_fulltex