Necrostatin-1 prolongs latency to convulsion in mice exposed to high oxygen partial pressure

Introduction: Exposure to very high oxygen partial pressure may cause central nervous system oxygen toxicity (CNS-OT). The role of necroptosis in the pathogenesis of CNS-OT is still unclear. Methods: In experiment one, male C57BL/6 mice in the oxygen toxicity (OT) group (n = 5) and necrostatin-1 (Nec-1; a necroptosis inhibitor) (1.5 mg·kg-1, intraperitoneal) group (n = 5) were exposed to pure oxygen at 600 kPa, and the latency to tonic-clonic seizure was recorded. In experiment two, mice were divided into three groups: control group (n = 11), OT group (n = 12) and Nec-1 group (n = 12). Nec-1 was intraperitoneally administered 30 min before oxygen exposure. Mice in the OT group and Nec-1 group were exposed to pure oxygen at 400 kPa for 30 min, and then sacrificed; the brain was harvested for the assessment of inflammation, oxidative stress and necroptosis. Results: Experiment one. Nec-1 pre-treatment significantly prolonged the latency to seizure (245 [SD 18] seconds in the OT group versus 336 (34) seconds in the Nec-1 group). Experiment two. Nec-1 pre-treatment markedly reduced inflammatory cytokines and inhibited cerebral necroptosis, but failed to significantly suppress cerebral oxidative stress. Conclusions: These findings indicate necroptosis is involved in the pathogenesis of CNS-OT, and inhibition of necroptosis may prolong seizure latency, but the specific mechanisms should be investigated further.

Formation of Nickel Oxide Nanocuboids in Ferromagnetic La2Ni1−xMn1+xO6

The control of the spontaneous formation of nanostructures at the surface of thin films is of strong interest in many different fields, from catalysts to microelectronics, because surface and interfacial properties may be substantially enhanced. Here, we analyze the formation of nickel oxide nanocuboids on top of La2Ni1−xMn1+xO6 double perovskite ferromagnetic thin films, epitaxially grown on SrTiO3 (001) substrates by radio-frequency (RF) magnetron sputtering. We show that, by annealing the films at high temperature under high oxygen partial pressure, the spontaneous segregation of nanocuboids is enhanced. The evolution of the structural and magnetic properties of the films is studied as a function of the annealing treatments at different temperatures. It is shown that the formation of NiOx nanocuboids leads to a nanostructured film surface with regions of locally different electrical transport characteristics.

Effect of Aluminum on Microstructure and High-Temperature Oxidation Resistance of Austenitic Heat-Resistant Steel

The ZG40Cr20Ni20Alx (x = 0, 1.76, 3.45, and 5.34) heat-resistant steel has been newly developed on the basis of HK40 steel for aggressive oxidizing environments. The results reveal that the Al greatly enhances the oxidation resistance of ZG40Cr20Ni20 steel at high temperatures. The mass gain of ZG40Cr20Ni20 upon oxidation at 1100 °C for 480 h is up to 103.6 mg/cm2, while the values for the steels containing 1.76 and 3.45 wt% Al are sharply decreased to 6.1 and 5.4 mg/cm2, respectively. Both of their matrix phases are still austenite, which is the same as that of ZG40Cr20Ni20. Their FeCr2O4 spinel oxide scales appear to be more stable under high oxygen partial pressure than that of ZG40Cr20Ni20, and the continuous Cr2O3 film appears between their matrix and spinel oxide. As for the steel with 5.34 wt% Al, the mass gain is only 1.1 mg/cm2. Its matrix is compared to those of austenite and ferrite, and the oxide scale is continuous Al2O3.

Effect of Oxygen Potential Gradient on Mass Transfer in Polycrystalline α-Alumina at High Temperature

The oxygen permeability of polycrystalline α-alumina wafers, which served as model alumina scales formed on heat-resistant alloys, was evaluated at a temperature of 1873 K. Mass transfer along grain boundaries (GBs) in an alumina wafer exposed to a large oxygen potential gradient (dμO), where both oxygen and aluminum mutually diffuse along GBs, was analyzed using 18O2 and SIMS. 18O was concentrated at GB ridges on the high oxygen partial pressure (PO2(hi)) surface and along the GBs near the PO2(hi) surface. 18O adsorbed on the surface diffused almost immediately to surface GBs, resulting in the formation of new alumina by reaction with aluminum diffusing outward along the GBs. Oxygen GB diffusion coefficients in the vicinity of the PO2(hi) surface were determined from the 18O depth profile along each GB for the 18O map of the cross section of the exposed alumina wafer. The oxygen GB diffusion coefficients were comparable to the values calculated from the oxygen permeability constants assuming an electronic conductivity and were obviously lower than those of oxygen GB self-diffusion without an oxygen potential gradient.

Roles of an oxygen Frenkel pair in the photoluminescence of Bi3+-doped Y2O3: computational predictions and experimental verifications

The photoluminescence intensity of Bi-doped Y2O3 is increased in a high oxygen partial pressure atmosphere due to the healed oxygen vacancy.