Silver nanoparticles (AgNPs) are widely used as antibacterial agents and anticancer drugs, but often their low stability limits their mass production and broad applications. The use of niosomes as a carrier to protect and envelop AgNPs gives a new perspective to solve these problems. In this study, AgNPs were functionalized with sodium 3-mercapto-1-propanesulfonate (3MPS) to induce hydrophilic behavior, improving loading in Tween 20 and Span 20 niosomes (NioTw20 and NioSp20, respectively). Entrapment efficiency was evaluated by UV analyses and is around 1–4%. Dimensions were investigated by means of dynamic light scattering (DLS) (<2RH> = 140 ± 4 nm and <2RH> = 251 ± 1 nm respectively for NioTw20 + AgNPs and NioSp20 + AgNPs) and were compared with those by atomic force microscopy (AFM) and small angle X ray scattering (SAXS) analyses. Stability was assessed in water up to 90 days, and both in bovine serum and human serum for up to 8 h. In order to characterize the local structure of niosomes, SAXS measurements have been performed on Tween 20 and Span 20 empty niosomes and loaded with AgNPs. The release profiles of hydrophilic probe calcein and lipophilic probe Nile Red were performed in HEPES buffer and in human serum. All these features contribute to conclude that the two systems, NioTw20 + AgNPs and NioSp20 + AgNPs, are suitable and promising in the field of biological applications.

Strontium Vanadium Oxide-Hydrides: "Square-Planar" Two-Electron Phases.-SrVO 2H, Sr2VO3H, and Sr3V2O5H2 are prepared by topochemical replacement of oxide ions in SrVO 3, Sr2VO4, and Sr3V2O7, resp., by hydride ions using CaH2 (600-630 C). The samples are characterized by powder neutron and X-ray diffraction and magnetic measurements. SrVO2H crystallizes in the tetragonal space group P4/mmm. Sr 2VO3H and Sr3V2O5H2 crystallize in the orthorhombic space group Immm. The structures of the new phases contain sheets or chains of apex-linked V III O4 squares stacked with SrH layers/chains. All three oxide-hydride phases show surprising strong antiferromagnetic coupling, with SrVO2H exhibiting a Neel temperature >300 K. The "parent" materials of a number of unconventional superconducting phases are antiferromagnetic insulators, and the unusual magnetic properties of the strontium vanadium oxide-hydride phases may be a prelude to similar behavior. -(DENIS ROMERO, F.; LEACH, A.; MOELLER, J. S.; FORONDA, F.; BLUNDELL, S. J.; HAYWARD*, M. A.; Angew. Chem., Int. Ed. 53 (2014) 29, 7556-7559, http://dx.doi.org/10.1002/anie.201403536 ; Dep. Chem., Univ. Oxford, Oxford OX1 3QR, UK; Eng.) -W. Pewestorf 40-015

Single crystals of three compositions in the Fe-Ni system (30% Ni, 50% Ni, and 76% Ni) were irradiated with neutrons (0.5×1018 neutron/cm2) in the presence of a magnetic field of 2000 Oe. Neutron irradiation affected the properties of all three compositions. In the 30% Ni alloy, the temperature at which the martensitic transformation starts was raised by neutron irradiation from 213° to 262°K while the temperature range for almost complete transformation was greatly broadened from a 9° to a 139° width. These effects of changing the transformation that were produced by neutron irradiation were simulated by cold rolling. The 50% Ni alloy showed a uniaxial anisotropy which is maximum when the magnetic field was directed in the [001] direction and a minimum in the [111] direction. This behavior which differs from the usual magnetic annealing effect tends to substantiate the work of Pauleve et al. The latter have shown the existence of an ordered phase in the 50% Ni alloy. As a result of neutron irradiation, the 76% Ni alloy became highly ordered and a high value of crystal anisotropy was obtained in a relatively short period of time. This work indicates that neutron irradiation at the proper temperature is a powerful method of obtaining long-range ordering in certain alloys of the Ni-Fe system.

No abstract