Low PO2 Research Articles

Mouse Cardiac MitobkCa Associates with β1 Subunit Favoring Channel Expression and Activity

We previously showed that in rat cardiomyocytes two types of mitoBKCa are present with high and low Po (∼0.85 and ∼0.01, respectively, at −60 mV in 12 µM Ca2+). We hypothesized that this difference could be related to the association with regulatory subunits. As first step, we investigated the role of BKCa β1 subunit by characterizing cardiac mitoBKCa properties in wild type (wt) and β1 KO mice. In wt mice, mitoBKCa was frequently recorded (in 6 out of 7 patches and 3 different preparations), had a conductance of ∼313 ± 8 pS (n=4) resembling that of mitoBKCa channel from rat (∼305 ± 19 pS, n=7), and was Ca2+ (n=2) and paxilline sensitive (n=3). In contrast to rat, wt mice had predominantly one population of mitoBKCa with a high open probability (Po∼0.8) at all membrane potentials tested (−80 to +80 mV, in 12 µM Ca2+). Interestingly, while in wt mice mitoBKCa were frequently recorded, in β1 KO, mitoBKCa was recorded only in 5 out of 24 patches (n=5 preparations). This channel had a similar conductance as the wt channel but with a much lower Po (∼0.25 vs. ∼0.8 at +60 mV in 12 µM Ca2+). These results are consistent with the view that in cardiac mitochondria, mitoBKCa is forming a complex with its β1 subunit favoring mitoBKCa expression and a high channel activity. A contribution of alternative subunits to mitoBKCa targeting and function needs further investigation. Supported by NIH and AHA.

Encroachment of titanium oxide on Ni surface for Ni/TiO2 under reducing atmosphere

The Ni-titania (TiO2) system was investigated to understand the phenomenon of titania encroachment on Ni surface as a function of temperature and oxygen partial pressure (PO2) under reducing atmosphere. A network-structured Ni film with widths of about 10μm was prepared on titania. It is found that encroachment of non-stoichiometric TiO2−x to the Ni surface occurs when TiO2 is reduced to TiO2−x with random point defects, as the PO2 is within the range defined by Ni-NiO and TiO2−x–TinO2n−1 equilibria. On the other hand, no encroachment to the Ni surface occurs at much lower PO2, where TiO2 is reduced further to the Magneli phase TinO2n−1 with ordered shear structure. A possible driving force for TiO2−x encroachment to the Ni surface may be attributed to the high surface energy of TiO2−x with disordered point defects. Furthermore, these results indicate the possible role of fast Ti diffusion in TiO2−x which drives its encroachment to the Ni surface.

Oxidation After Breakdown of the Chromium-Rich Scale on Stainless Steels at High Temperature: Internal Oxidation

Breakaway oxidation of alloy 304L at 600 degrees C was studied in four environments (O-2 + H2O + KCl, O-2 + H2O + SO2 + KCl, H-2 + H2O + Ar, O-2 + K2CO3) for up to 168 h. The resulting scales were investigated by FIB/SEM, SEM/EDX, STEM/EELS, STEM/EDS and oxidation was elucidated by thermodynamic calculations (Thermo-Calc). The initial thin protective scale broke down in all cases. After breakaway, the scale consisted of two layers, i.e. an inward growing spinel/reaction zone and an outward growing iron-rich layer. The general features and microstructure of the scales after breakaway were similar in all environments and were explained in terms of: (1) Different diffusivities of Cr3+ and Fe2+ in the spinel oxide. (2) The appearance of a miscibility gap in the FeCr and FeCrNi spinel oxides. (3) The equilibrium composition of the spinel (at low pO(2) Ni is not present in the spinel).

Two-fold stoichiometry relaxation — Simulated relaxation kinetics of ionic and electronic defect concentrations

The relaxation kinetics of defect concentrations in an oxide containing protons, oxygen vacancies, and holes after an increase of water partial pressure are simulated using materials parameters representative for perovskite proton conductors. Different regimes are identified (e.g. single-fold chemical diffusion of water at low pO2, two-fold relaxation at high pO2). It is shown that the analysis of ionic defect concentrations (which could be measured e.g. by thermogravimetry) and electronic defect concentrations (detectable by conductivity relaxation) yields different effective diffusion coefficients. Owing to the transition between different defect chemical and diffusion regimes, extracted effective activation energies are related to the fundamental transport parameters in a complex way.

Oxygen sensing by the carotid body: mechanisms and role in adaptation to hypoxia.

Oxygen (O2) is fundamental for cell and whole-body homeostasis. Our understanding of the adaptive processes that take place in response to a lack of O2(hypoxia) has progressed significantly in recent years. The carotid body (CB) is the main arterial chemoreceptor that mediates the acute cardiorespiratory reflexes (hyperventilation and sympathetic activation) triggered by hypoxia. The CB is composed of clusters of cells (glomeruli) in close contact with blood vessels and nerve fibers. Glomus cells, the O2-sensitive elements in the CB, are neuron-like cells that contain O2-sensitive K(+)channels, which are inhibited by hypoxia. This leads to cell depolarization, Ca(2+)entry, and the release of transmitters to activate sensory fibers terminating at the respiratory center. The mechanism whereby O2modulates K(+)channels has remained elusive, although several appealing hypotheses have been postulated. Recent data suggest that mitochondria complex I signaling to membrane K(+)channels plays a fundamental role in acute O2sensing. CB activation during exposure to low Po2is also necessary for acclimatization to chronic hypoxia. CB growth during sustained hypoxia depends on the activation of a resident population of stem cells, which are also activated by transmitters released from the O2-sensitive glomus cells. These advances should foster further studies on the role of CB dysfunction in the pathogenesis of highly prevalent human diseases.

The origin of grain boundary capacitance in highly doped ceria.

The origin of a grain-boundary capacitance in mixed oxide-ion/electronic conductors has been investigated for the case of Ce0.8Sm0.2O1.9-δ using a.c. impedance spectroscopy under low pO2 from 250 to 400 °C. The observed capacitance is interpreted in terms of Ce(III):4f(1) electrons first introduced into the grains and not into the grain boundaries.

Investigation of Oxygen Transport Paths in Geometrically Defined Thick-Film Composite Pt Electrodes on YSZ

Thick-film platinum (Pt) model electrodes with defined geometry screen-printed on yttria stabilized zirconia (YSZ) substrate were investigated to identify oxygen reactions and transport pathways in the Pt|YSZ electrode system. A 3D reconstruction of the electrode based on Focused Ion Beam Scanning Electron Microscopy (FIB-SEM) data was made to confirm that no percolating pores exist. Electrochemical impedance spectroscopy (EIS) was performed at 800°C and oxygen partial pressures (pO2) between 10−4 and 1 bar. The experimental data was interpreted using a Randles equivalent circuit. By variation of electrode area and three phase boundaries as well as electrode thickness, two oxygen transport pathways were found: an electrode surface path which contributes to the conductivity mostly at low pO2 and an electrode bulk path that represents the dominating path at high pO2. An advanced electrode layout enabled the separation of the transport pathways and confirmed that the two paths are parallel.

Modified atmosphere generated during storage under light conditions is the main factor responsible for the quality changes of baby spinach

Minimally processed products are generally exposed to low temperature and uncontrolled light conditions during the supply chain. The positive effect of low temperature on quality of baby spinach is widely reported, but there is little information available about the light effect. The objective of this study was to obtain insight about the cause-effect of light exposure of baby spinach on leaf quality and senescence parameters. Minimally processed baby spinach was stored in passive Modified Atmosphere Packaging (MAP) and in Controlled Atmosphere (CA) under different light conditions. In passive MAP, three very different headspace gas compositions within the bags due to photosynthesis and respiration reactions were generated that strongly affected the quality characteristics. To isolate the light effect from the atmosphere composition influence, and thus understand the mechanisms causing the quality changes, baby spinach was stored under two CA of 0.5kPa O2+10kPa CO2 (low O2+high CO2 levels) and air combined with 2 light conditions (continuous light and darkness). The changes observed under the different light conditions were mainly caused by the differences in gas composition. Under light, MAP with high O2 partial pressure (pO2) and low CO2 partial pressure (pCO2) was detrimental because of the growth of Pseudomonas spp. and the progress in tissue senescence due to oxidative stress, increasing cell damage, lipid peroxidation and chlorophyll degradation. Under darkness, MAP with low pO2 and high pCO2 was also detrimental because of the intense off-odour developments, the increase in pH and electrolyte leakage and the reduction in chlorophyll fluorescence. Our results showed that the modified atmosphere generated with exposure to the different light conditions affects the quality of baby spinach mainly because of the high pO2 under light and high pCO2 under darkness.

The suitability of some blood gas and biochemical parameters as diagnostic tools or early indicators of ascites syndrome in broiler sire lines.

In recent few years, there have been some attempts to find a reliable indicator trait as a selection criterion against susceptibility to ascites syndrome (AS). Blood parameters were of great interest as they could be measured in live animals without implementing an ascites-inducing challenge (AIC). In this work, the suitability of some blood parameters was evaluated for diagnosing AS-susceptible chicks in later steps of the disease in trial 1 as well as their early predictive ability in trial 2. In the first trial, one hundred 1-day-old chicks from two pure broiler lines namely S1 and S2 and, in the second trial, 226 1-day-old chicks from line S2 were subjected to AIC. Saline drinking water (1200mg/l) and lower-than-standard ambient temperatures were the implemented AICs in trials 1 and 2 respectively. The blood parameters including pH, partial pressure of O2 (pO2 ), partial pressure of CO2 (pCO2 ), bicarbonate ion concentration (BIC), percentage of haematocrit (HCT) and saturated haemoglobin (SaO2 ) were measured twice per each bird at days 28 and 35 in trial 1 and once in trial 2 at day 21. The results of the first trial revealed that in line S2 some of the blood parameters differed significantly between the ascitic and non-ascitic groups following exposure to AIC. In this line, the incidence of AS was accompanied by a lower pO2 , SaO2 and BIC, while with higher pCO2 and HCT values. In the second trial, however, although almost all of the parameters showed meaningful differences between the ascitic and non-ascitic broilers, only mean difference of BIC parameter was statistically significant. The general conclusion of this study is that the blood parameters can somewhat have diagnostic ability in the condition in which the AIC is already present, whereas the results did not approve their usefulness as early predictors of AS.

Innovative solid oxide fuel cells based on BaIn0.3Ti0.7O2.85 electrolyte and La2Mo2O9 amorphous reduced phase as anode material

This article presents elaboration of electrolyte-supported solid oxide fuel cells based on the oxide ion conductor BaIn0.3Ti0.7O2.85 (BIT07) as electrolyte, the amorphous reduced phase of La2Mo2O9 (La2Mo2O7-y) as anode which presents a mixed ionic and electronic conduction in low pO2 and La0.6Sr0.4Co0.2Fe0.8O3−δ (LSCF) as cathode. Electrode materials have been deposited by screen-printing on BIT07 substrate. In order to avoid chemical reactivity between BIT07 and La2Mo2O9, a thin layer of Ce0.9Gd0.1O1.95 (CGO) has been used. Electrochemical performance of the single cell has been characterized by I–V measurements and impedance spectroscopy. Encouraging performance of 40 mW cm−2 at 700 °C is obtained with a thick electrolyte layer. Finally, ageing test of the cell at 700 °C during 800 h has been done with a low rate of performance loss of 4.4 × 10−3% h−1. No degradation of the electrolyte material is reported and stability of the anode material after operating the fuel cell is discussed.

Causes and consequences of mid-Proterozoic anoxia

Evidence for low pO2 and a ferruginous ocean characterize the mid-Proterozoic (1.8–0.8 Ga). Considerations of redox sources and sinks imply that generation of O2 via organic carbon (Corg) burial must be low to maintain a low pO2 atmosphere for geologically long intervals, yet low oxygen should result in increased Corg preservation. Marine export production must therefore be low to limit Corg burial and O2 generation. Formation of ferrous phosphate can buffer deepwater phosphate (Pi) to levels an order of magnitude or more below those in the modern ocean, limiting export production. Low deepwater Pi is consistent with the hiatus in sedimentary phosphorite deposits during the mid-Proterozoic, and low pO2 limits formation of sedimentary iron deposits (BIF). We propose that low pO2 was maintained by P limitation resulting from ferrous phosphate buffering. The near-absence of BIF and phosphorite deposition is direct and indirect consequences of the low pO2, respectively.

Impact of Corneal Endothelial Dysfunctions on Intraocular Oxygen Levels in Human Eyes.

We studied the implications of corneal endothelial dysfunctions on oxidative stress in the anterior segment via in vivo measurements of oxygen partial pressure (pO2) in the anterior chamber (AC) of human eyes. We recruited 51 patients undergoing cataract surgery and/or endothelial keratoplasty (EK). Endothelial cell density (ECD; n = 33) and central corneal thickness (CCT; n = 41) were measured on patients with relatively clear corneas. Before surgery, an oxygen sensor was introduced into the AC via a peripheral corneal paracentesis. In all patients, seven measurements of pO2 were obtained by positioning the flexible tip near the endothelium at the central cornea, at four cardinal subendothelial locations near the midperipheral cornea, and in the mid-AC and AC angle. In patients with pseudophakia or eyes undergoing cataract surgery, pO2 also was measured near the lens surface and in the posterior chamber. Consistent with our previous reports, a steep oxygen gradient was noted in the anterior segment of normal controls (n = 24). In patients with endothelial dysfunctions (n = 27), there was a significant increase of pO2 at all five subendothelial locations without a significant increase of pO2 in the AC angle. By regression analyses, subendothelial pO2 correlated inversely with ECD and positively with CCT in patients with endothelial dysfunctions. This study demonstrates an even steeper intraocular oxygen gradient in eyes with corneal endothelial dysfunctions. It suggests that the reduced oxygen consumption in corneal endothelial cells may increase oxidative stress in the AC and the existence of an alternative aqueous inflow pathway that maintains a relatively low and constant pO2 at the AC angle.

Hemothorax Management After Endovascular Treatment For Thoracic Aortic Rupture

The aim was to describe and analyze the management of hemothorax (HTX) and the occurrence of respiratory complications after endovascular repair of thoracic aortic rupture (TEVAR). This was a multicenter study with retrospective analysis. Between November 2000 and December 2012, all patients with confirmed HTX due to rupture of the descending thoracic aorta treated with TEVAR were included. Respiratory function (acid base status, Pao2, Paco2, lactate, and respiratory index) was monitored throughout hospitalization. Primary endpoints were survival and post-operative respiratory complications. Fifty-six patients were treated. The mean age was 62±21 years (range 18-92 years). Etiology included traumatic rupture (n=23, 41%), atherosclerotic aneurysm (n=20, 36%), Debakey type IIIa dissection (n=8, 14%), and penetrating aortic ulcer (n=5, 9%). The primary technical success of TEVAR was 100%. The in hospital mortality rate was 12.5% (n=7). Hemothorax was drained in 21 (37.5%) cases. In hospital respiratory complications occurred in 23 (41%) patients who required a longer intensive care unit stay (days 2.3±0.7 vs. 1.9±0.8, p=.017), and hospitalization (26±17 vs. 19±17, p=.021). Those who developed post-operative respiratory complications had lower pre-operative PO2 values (mmHg, 80±24 vs. 91±21, p=.012). Respiratory complications and in hospital mortality did not differ among aortic pathologies (p=.269 and p=1.0, respectively), nor did in hospital mortality differ between patients with and without respiratory complications (13% vs. 12%; p=.990). Thoracic aortic rupture still has a high mortality rate. Respiratory complications have not been eliminated by endovascular repair. HTX evacuation may have had a positive influence on the survival in these patients. Although traumatic and degenerative ruptures are two significantly different scenarios, survival and respiratory outcomes were similar and were not affected by the underlying aortic disease.

Processing and electrochemical performance of manganese-doped lanthanum-strontium chromite in oxidizing and reducing atmospheres

This study reports the role of oxygen partial pressure (PO2) on the microstructural changes and compound formation during the exposure of (La0.75Sr0.25)0.95Cr0.7Mn0.3O3 (LSCM73) to 1400 °C to emulate oxygen transport membrane device fabrication. Results of electrochemical testing of LSCM73+8YSZ//8YSZ//LSCM73+8YSZ symmetrical cells, is also reported at 950 °C with time for 80 h in oxidizing (air) and reducing atmospheres (Ar-3%H2–3%H2O). Our results from elevated temperature exposure studies show a decrease in the density during exposure to reducing atmospheres due to the absence of liquid phase assisted sintering and inability to form SrCrO4. Formation of rhombohedral structure and MnCr2O4 spinel phase is evident in air whereas Mn3O4 phase formation occurs along with lattice transformation to cubic structure at lower PO2. Our experimental results are in agreement with LSCM73 phase diagram constructed using Thermo-Calc. Stable electrochemical performance is obtained in air and in reducing atmosphere, non-ohmic resistance increases with time which is attributed to Sr-segregation on LSCM73 surface and interaction between LSCM/8YSZ. No delamination of the electrode layer is observed in both oxidizing and reducing atmosphere.

Off-shelf fluxes across the southern Adriatic margin: Factors controlling dense-water-driven transport phenomena

The northern Adriatic Sea is a basin where dense shelf waters form during winters if the following favorable conditions are attained: high salinities, mainly related to low river water discharge (Po river in primis) during fall season, and strong heat fluxes induced by cold and dry Bora wind events blowing from north-east. Extremely favorable conditions to Northern Adriatic Dense Waters (NAdDW) formation characterized winter 2012 when, following several months of low Po river runoff, a strong event of Cold Air Outbreak (CAO) occurred from the end of January until mid-February. Consequently, the mean temperature of northern Adriatic waters dropped to about 6°C and exceptional densities (potential density anomaly locally exceeding 30.0kgm−3) were reached.The production and spreading mechanisms of dense water in the Adriatic Sea have been modeled by means of the COAWST (Coupled-Ocean–Atmosphere-Wave-Sediment-Transport) modeling system. The model builds upon a high-resolution (1km spaced horizontal grid), fully 3-D primitive equations hydrodynamic model coupled with a phase-averaged wave model and sediment routines, and is driven by simulated atmospheric forcings.The dataset used to assess model outputs relies on the measurements acquired during the dedicated field campaigns “Operation Dense Water”, a set of two rapid response cruises carried out in southern Adriatic during winter 2012, and by five mooring arrays deployed in the Southern Adriatic Margin (SAM) that allowed the continuous acquisition of temperature, salinity, currents and suspended matter samples.Results from the integrated data-model approach suggest that the NAdDW propagates along the shelf to the southern basin following both a shallower vein and a deeper stream, with a process characterized by a strong variability (mean value of 0.31Sv with peaks rapidly growing in the first weeks after the CAO up to 2.19Sv). Additionally, COAWST capability to couple different numerical models allowed to disentangle the relative importance of aspects on dense water generation, mixing and spreading, demonstrating how coupled runs can lead to volumes up to 50% larger with respect to uncoupled simulations. Additional light is shed on the transport pathways off the shelf and on possible sediment transport phenomena in the area, in this benefiting from an unprecedented spatial resolution and a new bathymetry reflecting very high resolution data acquired via multi-beam techniques. Although dense water propagation appears as a relatively large-scale process involving the whole western side of the SAM, topographic local discontinuities and seabed slopes appear crucial in triggering descent and governing flow patterns. The presence of suspended sediment along the water column, despite not significantly influencing the overall fluxes across sections, is responsible of pulling part of the veins towards deeper zones.

The squat lobster Pleuroncodes monodon tolerates anoxic “dead zone” conditions off Peru

The squat lobster Pleuroncodes monodon is a key species of the highly productive, but oxygen-poor upwelling system of the Eastern Tropical South Pacific. Observations of P. monodon in the water column off Peru have led to the hypothesis that anoxic conditions force this otherwise primarily benthic species to adopt a pelagic lifestyle. Here we show that off Peru, P. monodon can be found in the oxygenated surface water, but also on the anoxic seafloor. Our physiological experiments demonstrate that juvenile and adult specimens have a very low critical respiratory pO2 of 0.5 kPa and that adults survive anoxia for 30.5–70.5 h. Anoxic conditions at the seafloor should therefore force P. monodon to regularly migrate to the oxic surface layer in order to restore energy reserves and recycle metabolic end products of anaerobic metabolism. It was recently estimated that the ammonium supply mediated by diel vertical migrations (DVMs) of zooplankton and nekton considerably fuels bacterial anaerobic ammonium oxidation—a major loss process for fixed nitrogen in the ocean. These estimates were based on the implicit assumption that anoxia does not result in a down-regulation of ammonium excretion. We here show that exposure to anoxia elicits a fourfold reduction in ammonium excretion from 2.1 ± 0.6 µmol h−1 g dry weight−1 under normoxic to 0.5 ± 0.6 µmol h−1 g DW−1 under anoxic conditions in P. monodon. Estimates of ammonium supply to the anoxic core of oxygen minimum zones via DVM therefore are likely too high.

Transient Oxidation of a Nickel-Base Superalloy with Varying Oxygen Partial Pressure

The transient oxidation behaviour of a nickel-base superalloy in different oxygen partial pressures studied using electron and ion microscopy showed that at high pO2, a triple-layered oxide developed: outer nickel oxide, then a complex aluminium-chromium oxide, and inner alumina layer. Lower pO2 produced only alumina, as reduced oxygen activity suppressed nickel oxide formation. An aluminium-depleted region in the alloy with width proportional to pO2 was observed.

Placental hypoxia, endoplasmic reticulum stress and maternal endothelial sensitisation by sFLT1 in pre-eclampsia

The human placenta is a multifunctional organ that grows and adapts to increasing fetal demand and fluctuations in the intrauterine environment. It is subjected to physiological and pathological changes in local oxygenation, both of which induce adaptive changes. In early pregnancy a low PO2 is the normal physiological state and this is not hypoxic—there is no perturbation of ATP/ADP ratios and, if the placenta is sampled very rapidly, little HIF1α is detected in human first-trimester placental villi. Nonetheless, HIF1α can be increased and activated by culture. However, the placenta does show evidence of stress under pathological conditions. For example, in cases of pre-eclampsia where delivery by caesarean section is necessitated for maternal well-being before 34 weeks’ gestation, placental endoplasmic reticulum stress is evident. Cases delivered ≥34 weeks are indistinguishable from normal term controls. One consequence of placental stress, whether oxidative, related to the endoplasmic reticulum or immunological, is that factors are released into the maternal circulation, which affects the endothelium, leading to the maternal syndrome. Soluble FLT1 may contribute directly to this and the most likely mechanism is direct action on the maternal endothelium. sFLT1 is able to form a heterodimer with cell surface VEGF receptors and is therefore able to have a dominant negative effect (in addition to acting as a competitive inhibitor by simply binding vascular endothelial growth factor A [VEGFA] and placental growth factor [PlGF]). This leads in vitro to the sensitisation of endothelial cells to low levels of TNFα.

Scaling Kinetics and Scale Microstructure of Chromia Scales Formed on Ni-25%Cr Model Alloy during Oxidation in H2o-Containing High and Low pO2 Test Gas at 1000°C

The isothermal oxidation behaviour of a Ni25Cr model alloy was studied employing the JuSie-methodology, i.e. using specimens of different thickness for each specific test gas composition at 1000°C in dry and wet N2-1%O2 as well as in Ar-7%H2O. The oxidation mechanisms were evaluated using thermo-gravimetry and SEM/EBSD analyses of oxide scale cross sections. The ion beam polished oxide cross-sections were analysed in terms of oxide grain growth and nucleation rates of new oxide at the oxide-gas interface. The findings can be explained by considering the effect of H-defects and in-scale stress state on point defect concentrations in the chromium sub-lattice.

Ln2NiO4+δ (Ln = La, Pr) As Suitable Cathodes for Metal Supported Cells

In the last decade, thanks to their mixed ionic and electronic conductivity (i.e. MIEC properties), the lanthanide nickelates, Ln2NiO4+ δ (Ln = La, Pr, Nd) have attracted much attention as cathode for solid oxide fuel cells. Simultaneously, Metal Supported Cells (MSCs) for IT-SOFC application (typically 600 – 700 °C) have been developed in respect of several advantages including reduced cost and better thermal cycling resistivity. Nevertheless, the use of porous metal implies to sinter the constitutive elements of the cells under low pO2 (e.g. under N2, pO2 » 10-4 atm). In that respect, the chemical stability, thermal and chemical expansion when exposed to temperatures as high as 1400 °C, under pO2 as low as 10-4 atm of Ln2NiO4+ δ phases were studied through TGA (Thermal Gravimetry Analysis), XRD analyses, high temperature X-ray diffraction and Thermal Expansion Coefficient measurements. Electrochemical Impedance Spectroscopy measurements on Ln2NiO4+ δ//GDC//YSZ symmetrical half-cells sintered either in air or under argon at various temperatures have been performed in the range 500 °C to 800 °C, in air, at idc = 0 A. Pr2NiO4+δ, either sintered in air or under nitrogen at 1150 °C and then re-oxidized, shows the lowest polarization resistance values (Rp = 0.12 Ω.cm2 at 600 °C) while La2NiO4+δexhibits smaller polarization resistances when sintered under nitrogen, compared to air. Finally, the suitability of lanthanide nickelates in MSCs will be demonstrated and the relationship between cathode performances and structural and microstructural features will be discussed in details. Besides,modelling of the impedance data will be emphasized.