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Further development of solid oxide fuel cell (SOFC) oxygen electrodes can be achieved through improvements in oxygen electrode design by microstructure miniaturization alongside nanomaterial implementation. In this work, improved electrochemical performance of an La

This article presents electrolytic deposition of thin Rare Earth (RE) coatings on Crofer 22 APU stainless steel substrates for high temperature applications, such as interconnects in solid oxide cell stacks. The deposition of coatings based on yttrium-, gadolinium-, lanthanum-, and cerium nitrates is discussed. The high temperature corrosion properties of surface-modified steels were examined using thermogravimetry and electrical resistivity measurements. Coatings and oxide microstructures were examined by XRD and SEM of surfaces and cross-sections. The results showed that the use of the RE element oxide layers reduced the growth of oxide scale, as evidenced by lower weight gain. The layers based on Y- and Gd-oxides showed the best corrosion protection properties. The electrical measurements showed that the surface-modified samples had lower resistance than the uncoated sample.

In this study, La0.8Sr0.2MnO3 (LSM) was used as the ceramic electrode in a (Bi1.50Y0.50)0.98Zr0.04O3+δ (BYO)-based solid electrolyte oxygen generator (SEOG) and its performance was compared with that of a previously studied high-fire Ag electrode. Among La0.6Sr0.4Co0.2Fe0.8O3, LaNi0.6Fe0.4O3, Cu1.4Mn1.6O4, and LSM materials, only LSM materials did not trigger any chemical reaction or interdiffusion with BYO at temperatures up to 900 °C. Two cell designs, Cell A, with a Bi1.71Nb0.25Ba0.04O3+δ (BBNO) interlayer and high-fire Ag electrode, and Cell B, with an LSM-BYO composite electrode, were obtained in this study. The cells were sandwiched between two modular SUS 316 planar interconnects using a ZnO–SiO2–Al2O3 glass sealant to form the SEOG device. Although Cells A and B possessed similar ohmic resistance (Ro) values, the polarization resistance (Rp) values of Cell A were 3.6 times larger than those of Cell B. Furthermore, the stability study of the cells operated at 600 °C for 12 h revealed that Ro increased from 0.79 to 3.17 Ω cm2 and Rp from 3.12 to 12.58 Ω cm2 for the Cell A, while Ro increased from 0.76 to 0.77 Ω cm2 and Rp from 0.87 to 1.12 Ω cm2 for the Cell B. Therefore, minor variations in the Ro and Rp of Cell B indicate the excellent stability of the electrode. The degradation of Cell A was caused by the migration of Ag and formation of voids and cracks adjacent to the anode/electrolyte interface under the DC field. Furthermore, the Cell A experienced a decrease in faradaic efficiency for current densities greater than 0.20 A cm−2 owing to the partial decomposition of BYO at the cathode. In contrast, the Cell B generated an oxygen flux of 1.29 cm⋅min−1 at 600 °C. In addition, the faradaic efficiency of Cell B remained consistent for current densities up to 0.35 A cm−2. Therefore, the SEOG using LSM-BYO as the cell electrode exhibited excellent stability and electrochemical performance.

The aim of this work was to prepare and examine the catalytic activity of nanometric CeO2 decorated with transition metal oxides – Ni, Co, Cu, Fe and Mn – towards a high-temperature methanation process under SOEC CO2/H2O simulated co-electrolysis conditions. Samples were prepared using the wet impregnation method via the conventional process and with the addition of native cyclodextrin. The influence of β-cyclodextrin (βCD) onto the size, dispersion and integration of the obtained metal nanoparticles was investigated. The differences between the catalysts’ reducibility revealed that samples prepared from βCD-containing solutions, in most cases, resulted in the creation of smaller MexOy NPs on the surface of the substrate material compared to those prepared using traditional nitrate solutions. The samples containing Ni and Co were the only ones that observably catalysed methane synthesis. The high dispersion and integration of NPs prepared via the proposed synthesis route resulted in increased catalytic activity and enhanced stability, which was most pronounced for the Co-impregnated sample. The methane production peak for Ni-βCD/CeO2 at 375℃ was characterised by nearly 99% CO conversion and 80% selectivity towards CH4 production. Co-βCD/CeO2 reached 84% CO conversion and almost 60% methane selectivity at 450℃. The usage of CeO2 coupled with βCD for the preparation of catalysts for high-temperature methane synthesis for use in SOECs gave promising results for further application.

In this work, the effect of the addition of graphene oxide (GO) to nickel-iron (NiFe) and cobalt-nickel-iron (CoNiFe) mixed oxide/hydroxide/(oxy)hydroxide catalysts on their morphological, structural, and oxygen evolution reaction (OER) catalytic activity is investigated. The catalysts are fabricated during two-step electrodeposition: the first step includes the deposition of GO flakes, which in the second step become reduced with simultaneous deposition of NiFe or CoNiFe. As a result, NiFe-GO and CoNiFe-GO are fabricated without any additives directly on the nickel foam substrate. A significant improvement of the OER activity was observed after combining NiFe with GO (OER overpotential η(10 mA·cm-2): 210 mV) compared to NiFe (η: 235 mV) and GO (η: 320 mV) alone. Different OER activity was observed for CoNiFe-GO. Here, the overall catalytic activity (η: 230 mV) increased compared to GO alone, however it was reduced in comparison with the CoNiFe (η: 224 mV). The latter was associated with the change in the morphology and structure of the catalysts. Further OER studies show that each of the catalysts has a specific role in influencing the process: the improvement in the OER by NiFe-GO results mainly from the structure of NiFe and the electroactive surface area of GO.

NdSrCo2O5+δ (NSCO) is a perovskite with an electrical conductivity of 1551.3 S cm−1 at 500 °C and 921.7 S cm−1 at 800 °C and has a metal-like temperature dependence. This perovskite is used as the cathode material for Ce0.8Gd0.2O2-δ (GDC)-supported microtubular solid oxide fuel cells (MT-SOFCs). The MT-SOFCs fabricated in this study consist of a bilayer anode, comprising a NiO–GDC composite layer and a NiO layer, and a NSCO–GDC composite cathode. Three cell designs with different outer tube diameters, GDC thicknesses, and NSCO/GDC ratios are designed. The MT-SOFC with an outer tube diameter of 1.86 mm, an electrolyte thickness of 180 μm, and a 5NSCO–5GDC composite cathode presents the best performance. The flexural strength of the aforementioned cell is 177 MPa, which is sufficient to confer mechanical integrity to the cell. Moreover, the ohmic and polarization resistance values of the cell are 0.22 and 0.09 Ω cm2 at 700 °C, respectively, and 0.15 and 0.03 Ω cm2 at 800 °C, respectively. These results indicate that the NSCO-GDC composite exhibits high electrochemical activity. The maximum power densities of the cell at 700 and 800 °C are 0.46 and 0.67 W cm−2, respectively, exceeding those of existing electrolyte-supported MT-SOFCs with similar electrolyte thicknesses.

Development of environmentally friendly, high performing oxygen evolution reaction (OER) catalysts is an important research challenge. In this work, iron doped strontium titanates with a general formula SrTi1-xFexO3-δ (x = 0.35, 0.50, 0.70, 0.90, and 1.00) denoted as STFx, were synthesized via a solid state reaction technique and characterized in terms of oxygen evolution reaction electrocatalysis in an alkaline electrolyte (0.1 M KOH). The produced powders were characterized by a high specific surface area (>20 m2 g−1), beneficial for OER. The evaluation of specific activity indicated the following trend of increasing performance: STF35 < STF50 < STF70 < SFO < STF90. The lowest overpotential at 10 mAcm−2 GEO of 410 mV (350 mV at 25 μA cm−2OX) was achieved by STF90 with the corresponding Tafel slope of 60 mV dec−1. The two materials with the highest Fe content (i.e. STF90 and SFO) showed, however, poor chemical stability in alkaline solution demonstrated by the dissolution of Sr. Based on the good electrochemical performance (~460 mV at 10 mA cm−2GEO, ~405 mV at 25 μA cm−2OX) and chemical stability for at least 30 days (no Sr dissolution) of STF50, it can be considered an interesting, working at room temperature OER catalyst based on non-toxic and abundant elements.

One of the most important modules of computer systems is the one that is responsible for user safety. It was proven that simple passwords and logins cannot guarantee high efficiency and are easy to obtain by the hackers. The well-known alternative is identity recognition based on biometrics. In recent years, more interest was observed in iris as a biometrics trait. It was caused due to high efficiency and accuracy guaranteed by this measurable feature. The consequences of such interest are observable in the literature. There are multiple, diversified approaches proposed by different authors. However, neither of them uses discrete fast Fourier transform (DFFT) components to describe iris sample. In this work, the authors present their own approach to iris-based human identity recognition with DFFT components selected with principal component analysis algorithm. For classification, three algorithms were used—k-nearest neighbors, support vector machines and artificial neural networks. Performed tests have shown that satisfactory results can be obtained with the proposed method.

Spinel oxides with the general formula Mn1.7Cu1.3-xFexO4 (x= 0, 0.1, 0.3, 0.5) were prepared and evaluated in this work for their properties at high temperatures. The effect of partially substituting Cu by Fe has not been studied so far for this group of materials and is thus evaluated in this work. Mn1.7Cu1.3-xFexO4 powders were synthesised by a soft chemistry process and studied in terms of crystallographic phase analysis, electrical conductivity, thermal expansion, and sinterability behaviour. The results show that the Fe content has a significant influence on the phase composition and the resulting properties. Characterisation of the dilatometry and conductivity coupled with XRD phase analysis across a wide temperature range allowed the relations between the materials properties and compositions to be observed. The results indicate that Mn1.7Cu0.8Fe0.5O4 is a promising material for use as a protective coating for interconnects in intermediate temperature Solid Oxide Fuel Cells.

Ce0.8Gd0.2O1.9 (CGO) barrier layers are required to mitigate the chemical reactions between Sr-containing oxygen electrode materials and Zr-based oxygen ion conductors in high-temperature solid oxide cells. Barrier layers produced by different methods were studied in this work. As a reference, a cell with no barrier layer was measured. The application of the powder-processed barrier layers, considerably increases the performance. For further comparison, thin and dense CGO layers were produced by a low-temperature spray pyrolysis process. Three different thicknesses were evaluated: ∼300 nm, ∼700 nm and ∼1500 nm. The best performance was found for the ∼700 nm thick CGO barrier layer. It showed low ohmic and polarisation resistances. The low thickness and high density of the CGO barrier layer were found to be the important factors. The cells with the ∼700 nm CGO barrier layers were also evaluated for their electrolysis performance as well as fuel cell durability.

The aim of this study was to evaluate a new catalytic material for biogas-fuelled DIR-SOFCs. This material was a perovskite-type SrTiO3 doped with La, Ce and Ni of a general formula La0.27Sr0.54Ce0.09Ni0.1Ti0.9O3-σ (LSCNT). Additional preparation steps were undertaken to promote a nickel exsolution process. Heat post-treatment of powders in a humidified H2 resulted in an intensive growth of nickel nanoparticles (NPs) while the reduction temperature was increased gradually from 800 to 1200 °C. A selected reduction temperature equal to 900 °C gave the NPs an average size of 22 nm. The prepared material was used as a functional layer deposited onto the anodic site of a Ni/YSZ-supported SOFC to promote the effective reforming of synthetic and H2S-contaminated biogas at 750 °C. It was found that after 130 h of operation in a 60% CH4/40% CO2 mixture, the fuel cell with an additional LSCNT layer showed higher power density, and no carbon deposits were observed. However, 20 ppm of H2S present in the fuel caused a full deactivation of both the reference and SOFC with LSCNT layer. Cyclic tests in sour biogas revealed that the fabricated anodic layer is much more resistant to sulfur poisoning compared to a bare Ni/YSZ anode. Recovery of overall performance after 3 poisoning cycles was nearly 90% for the fuel cell with the LSCNT layer, while the unmodified one reached only 75%. The concentrations of the exhaust gases, such as CH4, CO2, and CO, were continuously measured in situ using a FTIR-based technique. A thermochemical analysis revealed that the investigated material ensured much better biogas reforming stability over the whole testing time and strongly promoted catalytic reactions.

The Pr and Sm co-doped ceria (with up to 20 mol.% of dopants) compounds were examined as catalytic layers on the surface of SOFC anode directly fed by biogas to increase a lifetime and the efficiency of commercially available DIR-SOFC without the usage of an external reformer. The XRD, SEM and EDX methods were used to investigate the structural properties and the composition of fabricated materials. Furthermore, the electrical properties of SOFCs with catalytic layers deposited on the Ni-YSZ anode were examined by a current density-time and current density-voltage dependence measurements in hydrogen (24 h) and biogas (90 h). Composition of the outlet gasses was in situ analysed by the FTIR-based unit. It has been found out that Ce0.9Sm0.1O2-δ and Ce0.8Pr0.05Sm0.15O2-δ catalytic layers show the highest stability over time and thus are the most attractive candidates as catalytic materials, in comparison with other investigated lanthanide-doped ceria, enhancing direct internal reforming of biogas in SOFCs.

GdCoO3-δ, Gd0.975Na0.025CoO3-δ, Gd0.98K0.02CoO3-δ, Gd0.98Ca0.02CoO3-δ, and GdCo0.99Mg0.01O3-δ ceramics were prepared via a solid-state reaction route. Among the dopants studied, substitution with Ca2+ slightly enhanced the densfication of GdCoO3 ceramics. All the lattice parameters of the doped ceramics were larger than those of pure GdCoO3-δ ceramic (a = 5.223 A, b = 5.389 A and c = 7.451 A), and their cell volumes increased by 0.30% to 1.40% because the substitution ions were larger in size. X-ray diffraction and scanning electron microscopy results indicate that no second phase is present. The average grain size of the GdCoO3 ceramics (7.6 μm) slightly increased by the Na+, K+ and Mg2+ substitutions and decreased by the Ca2+ substitution. In all cases, the intergranular fracture surfaces revealed the presence of trapped pores due to rapid grain growth. The oxidation states and percentages of Co ions were determined from the Co 2p X-ray photoelectron spectra. Na+, K+, Ca2+, and Mg2+ substitution in the GdCoO3-δ ceramic resulted in slight oxidation of the Co ions accompanied by a decrease in oxygen vacancies. After porosity correction using the Bruggeman effective medium approximation, Gd0.98Ca0.02CoO3-δ had the largest electrical conductivity at all measured temperatures among the compositions studied, which was 144% higher at 500 °C and 16% higher at 800 °C compared to those of GdCoO3-δ ceramic (500 °C: 133.3 S·cm−1; 800 °C: 692.4 S·cm−1). The substantial increase in the electrical conductivity of the doped GdCoO3-δ ceramics is due to the electronic compensation of acceptor doping, $$ {\mathrm{N}a}_{Gd}^{"} $$ , $$ {K}_{Gd}^{"} $$ , and $$ {Ca}_{Gd}^{\prime } $$ , which resulted in the formation of hole carriers and the elimination of oxygen vacancies ( $$ {V}_o^{\bullet \bullet } $$ ), which generated additional Co4+ ( $$ {Co}_{Co}^{\bullet } $$ ).

The aim of this paper was to investigate an influence of the nanocrystalline Ce0.8A0.2O2-δ (A = Mn, Fe, Co, Ni, Cu) materials on the direct internal reforming of biogas in SOFC. Structural analysis of fabricated compounds has been done. An in-situ analysis of a composition of outlet gases from operating SOFC was performed using FTIR spectroscopy with simultaneous electrical tests. It was found out, that type of dopant strongly affects biogas reforming process. The differences in absolute values of current density resulted mostly from a microstructure and probably phase composition of a deposited layers. Fuel cells with Ce0.8Co0.2O2-δ and Ce0.8Ni0.2O2-δ additional layers presented the highest drop of current density after switching from hydrogen to biogas, but simultaneously they were the most stable in time. Additional chemical analysis revealed that steam reforming and methane pyrolysis might be dominating reactions while working in biogas atmosphere.

This work evaluates the effects of the sintering temperature (800 °C, 900 °C, 1000 °C) of SrTi1-xFexO3-δ (x = 0.35, 0.5, 0.7) porous electrodes on their electrochemical performance as potential oxygen electrode materials of solid oxide cells. The materials were prepared by a solid-state reaction method and revealed the expected cubic perovskite structure. After milling, the powders were characterised by a sub-micrometre particle size with high sinter-activity. It was shown that the lowest area specific resistance was achieved after sintering SrTi0.65Fe0.35O3 electrodes at 1000 °C, and SrTi0.5Fe0.5O3 and SrTi0.30Fe0.70O3 electrodes at 800 °C, which can be considered to be a relatively low temperature. In general, EIS measurements showed that increasing the Fe content results in lowered electrode polarisation and a decrease of the series resistance. Even though the studied materials have much lower total conductivities than state-of-the-art electrode materials (e.g. (La,Sr)(Co,Fe)O3), the polarisation resistances obtained in this work can be considered low.

This paper seeks to examine how the Mn–Co spinel interconnect coating microstructure can influence Cr contamination in an oxygen electrode of intermediate temperature solid oxide cells, at an operating temperature of 750 °C. A Mn–Co spinel coating is processed on Crofer 22 APU substrates by electrophoretic deposition, and subsequently sintered, following both the one-step and two-step sintering, in order to obtain significantly different densification levels. The electrochemical characterization is performed on anode-supported cells with an LSCF cathode. The cells were aged prior to the electrochemical characterization in contact with the spinel-coated Crofer 22 APU at 750 °C for 250 h. Current–voltage and impedance spectra of the cells were measured after the exposure with the interconnect. Post-mortem analysis of the interconnect and the cell was carried out, in order to assess the Cr retention capability of coatings with different microstructures.

Ovarian carcinoma (OC) forms outgrowths that extend from the outer surface of an afflicted organ into the peritoneum. OC outgrowth formation is poorly understood because there is limited availability of OC cell culture models to examine the behavior of cell assemblies that form outgrowths. Prompted by immunochemical evaluation of extracellular matrix (ECM) components, laminin γ1 and collagens, in human tissues representing untreated and chemotherapy-recovered OC, we developed laminin- and collagen-rich ECM-reconstituted cell culture models amenable to studies of cell clusters that can form outgrowths. We demonstrate that ECM promotes outgrowth formation in fallopian tube non-ciliated epithelial cells (FNE) expressing mutant p53-R175H and various OC cell lines. Outgrowths were initiated by cells that had undergone outward translocation and, upon mechanical detachment, could intercalate into mesothelial cell monolayers. Electron microscopy, optical coherence tomography (OCT), and small amplitude oscillatory shear experiments revealed that high ECM concentration increased ECM fibrous network thickness and led to high shear elasticity in the ECM environment. These physical characteristics were associated with the suppression of outgrowths. A culture environment with low ECM concentration mimicked viscoelasticity of malignant peritoneal fluids (ascites) and supported cell proliferation, cell translocation, and outgrowth formation. These results highlight the importance of ECM microenvironments in modulating OC growth and could provide an additional explanation of why primary and recurrent ovarian tumors form outgrowths that protrude into the peritoneal cavity.

Non-conducting BaO-B2O3-Al2O3-SiO2 parent glasses designed for solid oxide fuel cell (SOFC) sealing applications were prepared using the melt-quenching technique. The glass formation region was determined according to phase equilibrium relations and was found to be in the composition range 70BaO-(x)Al2O3-(10−x)B2O3-20SiO2 where 3.0

Doping of Na and K at La sites and of B at Si site in La10Si6O27 with oxyapatite structure and fabrication of their ceramics were made by the solid-state reaction method. It was found that partial substitution of Na+ and K+ on La sites decreased the sinterability of the La10Si6O27 based ceramics, whereas partial substitution of B3+ on the Si site improved the sinterability. Na+ and K+ substitutions in La10−xNaxSi6O27−x and La10−xKxSi6O27−x can suppress second-phase La2SiO5 formation, and, in this study, as the x value of the two substitutions reached 0.7 and 0.5, respectively, the La2SiO5 phase disappeared. Doping of Na+, K+, and B3+ all displayed the hindering effect of grain growth during sintering. Compositions of La9.3Na0.7Si6O26.3, La9.5K0.5Si6O26.5, and La10Si5.5B0.5O26.75 revealed the highest electrical conductivity in each system. La10Si5.5B0.5O26.75 ceramic sintered at 1575°C showed the highest electrical conductivity at temperatures above 600°C among all the apatite ceramics evaluated. The electrical conductivities of La10Si5.5B0.5O26.75 at 700°C and 800°C reported 0.011 S cm−1 and 0.024 S cm−1, respectively, which are superior or comparable to previous studies, and their activation energies for conduction were calculated to be 0.80 eV.

In this work, nanocrystalline layers based on the Pr, Gd co-doped CeO2 were investigated. For the preparation of thin layers, low-temperature spray pyrolysis technique was used. Different stoichiometries of the layers were produced for comparison on polished sapphire substrates. The microstructure of the prepared thin layers was studied by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS) and x-ray diffractometry (XRD). The total electrical conductivity as a function of Gd or Pr dopant were determined by DC electrical measurements using the Van der Pauw method in air atmosphere. The oxygen electrode interface analysis confirm protective character of the diffusion barrier layer based on doped CeO2.

The purpose of this study was to develop a method and software based on the Fourier Transform Infrared Spectroscopy for the in-situ, quantitative analysis of the composition of outlet gases from Solid Oxide Fuel Cell (SOFC). The calibration procedure performed at the beginning of the experiment indicated a polynomial dependence between the concentration of a calibrating gas (CO, CO2, CH4) and the corresponding integrated absorbance in particular wavenumber ranges. Further, it allowed determining a concentration of CO2, CO, CH4 and H2 in the outlet gas stream of the Ni–YSZ anode supported Direct Internal Reforming-SOFC fuelled by synthetic biogas (mixture of CO2 and CH4 in a volume ratio 2:3). The analysis was performed for over 90 h. Based on calculated concentration the conversion rates for both CH4 and CO2 gases were calculated, as well as the yields and selectivities of CO and H2. Also, the carbon balance was determined. In order to predict the direction of particular reforming reactions, a non-equilibrium analysis was performed. Namely, a thermodynamic probability of solid carbon formation was determined based on calculations of carbon activity coefficients. Obtained results indicated degradation of a fuel cell and corresponded well with electrical measurements where a decrease of power density in wet synthetic biogas was observed.

The 430L stainless steel powder with a mean particle size of 95 μm was studied to determine its high-temperature oxidation properties. Continuous thermogravimetric measurements were carried out for 100 h in air at temperatures in the range of 600–850 °C. Even though a considerable amount of Cr (up to ˜5 wt.% Cr) inside the grains was depleted – especially inside small grains – no breakaway oxidation was observed. This indicates that both the remaining Cr and the formed chromia scale remained protective with regard to the metallic core until the Cr concentration reached very low levels.

This work evaluates porous Sr0.86Ti0.65Fe0.35O3 (STF35) as a possible oxygen electrode material for Solid Oxide Cells. The powder synthesis was performed by solid state method. Characterization included DC electrical conductivity study of sintered bulk samples and impedance spectroscopy study of symmetrical electrodes deposited on gadolinium doped ceria substrates. Measurements were carried out in atmospheres with different pO2 levels: 0.1%–20% O2. Detailed equivalent circuit analysis was carried out in order to clarify the reaction pathway on porous electrode, which extends knowledge available for dense model electrodes. At 800 °C in 21% O2, the DC electrical conductivity of STF35 pellet was 0.6 S cm−1 and the polarization resistance of the electrode in the symmetrical cell was ∼100 mΩ cm2. Detailed impedance spectroscopy studies revealed that the largest contribution (∼80%) towards the polarization resistance is due to oxygen adsorption, which is limiting the oxygen reduction performance of the porous STF35 electrode. These results show the applicability of advanced impedance analysis methods (e.g. Distribution of Relaxation Times - DRT) for description of complex impedance electrode phenomena of porous electrodes.

In this work manganese cobalt spinel (MnCo2O4) coatings were deposited on steel substrates by spray pyrolysis at 390 °C. This is at much lower temperatures than previously reported (typically in excess of 900 °C). It was possible to produce coatings with well controlled thickness (2-5-10 μm). The as-deposited coatings were evaluated for their microstructural changes and electrical conductivity up to 800 °C. Results confirm the formation of a single phase spinel with high density and electrical conductivity. Based on the obtained results, it might be concluded that spray pyrolysis is a very promising method to develop protective coatings for steel substrates at low temperatures overcoming limitations of many other methods.

Aims Gestational trophoblastic neoplasms (GTN) exemplify a rare, mostly curable but highly aggressive disease. It is often associated with a rapid formation of distant metastases and most likely with an intense neoangiogenesis processes. The aim of the study was to analyze markers in serum of patients with GTN before chemotherapy compared to healthy pregnant women. Main methods In this study sixteen protein angiogenesis markers were evaluated in serum of 21 patients with GTN before chemotherapy and compared with healthy pregnant women. Markers were measured using BioPlex Pro Human Cancer Biomarker Panel 1 immunoassay. t-Tests and receiver operating characteristic curves were used for statistical analysis. Key findings Receiver operator curve analysis identified six proteins (sTIE-2, osteopontin, sIL-6α, sVEGFR-2, sEGFR, PECAM-1) which had sufficient sensitivity and specificity (AUC > 0,70) to distinguish GTN patients before the treatment from pregnant controls. The levels of three proteins (sTIE-2, osteopontin and sIL-6α) were altered in GTN patients before the treatment as compared to healthy controls (p = 0,0112; p = 0,0442; p = 0,0488, respectively) and thereby may serve as potential disease markers. Significance Serum concentration of proteins related to angiogenesis changes in the course of GTN and may appear useful in the diagnostic process of this disease.

In this work, the influence of the substitution of niobium by titanium in Y3Nb1-xTixO7-δ on the structural and electrical properties is reported. Several experimental techniques, i.e. X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), X-Ray Photoelectron Spectroscopy (XPS) and Electrochemical Impedance Spectroscopy (EIS), were applied to investigate the system Y3Nb1-xTixO7-δ. Titanium in Y3Nb1-xTixO7-δ is an acceptor-type dopant which charge is mainly compensated by oxygen vacancies, moreover, it may adopt different valence states, therefore, oxygen ion-, proton- and electronic-type conductivity are expected. Very interesting, non-monotonic changes in electrical and structural properties as a function of titanium content were observed. The competition between the increasing charge carrier concentration and structural phenomena such as short-range pyrochlore ordering and/or vacancy clustering was proposed as responsible for this non-monotonicity.

This study presents the use of matrix-assisted laser desorption and ionization mass spectrometry imaging (MALDI-MSI) directly on the tissue of two ovarian tumors that often present a diagnostic challenge, a low-grade serous borderline ovarian tumor and ovarian fibrothecoma. Different spatial distribution of m/z values within the tissue samples was observed, and regiospecific peaks were identified. Among the 106 peaks in the borderline ovarian tumor five, regiospecific peaks (m/z: 2861.35, 2775.79, 3368.34, 3438.43, 4936.37) were selected using FlexImaging software. Subsequently, the distribution of those selected peaks was visualized on the fibrothecoma tissue section, which demonstrated the differences in the tissue homo-/heterogeneous structure of both tumors. The comparison with the histopathological staining of the ovarian borderline tumor tissue section, obtained during serial sectioning, showed a close correlation of the molecular map with the morphological and histopathological features of the tissue and allowed the identification of different tissue types within the sample. This study highlights the potential significance of MSI in enabling morphological characterization of ovarian tumors as well as correct diagnosis and further prognosis than thus far seen in the literature. Osteopontin, tropomyosin and orosomucoid are only a couple of the molecules investigated using MALDI-MSI in ovarian cancer research. This study, in line with the available literature, proves the potential of MALDI-MSI to overcome the current limitations of classic histopathological examination giving a more in-depth insight into the tissue structure and thus lead to the more accurate differential diagnosis of ovarian tumors, especially in the most challenging cases.

Approximately, 5% of ovarian tumors have hormonal activity. Steroid cell tumors (SCTs) represent about 0.1% of all ovarian tumors. They cause hyperandrogenism associated with typical virilization. In this case report, we present 45-year-old women with unmalignant ovarian SCT-producing androgens which cause severe virilization and secondary amenorrhea lasting two years. Transvaginal ultrasound, computed tomography of adrenal glands, magnetic resonance imaging of small pelvis, laboratory tests (including serum concentration of FSH, LH, testosterone (T), androstenedione (A), dehydroepiandrosterone sulfate (DHEA-S), as well as ROMA index) were performed. During hormonal evaluation, elevated concentrations of serum T - on admission 1.72 ng/ml and one month later 3.75 ng/ml (normal range 0.08-0.82 ng/ml) and A - 24.90 ng/ml (normal range 0.40-3.40 ng/ml) were found. The ROMA index was within the normal range. Enlargement of the left ovary by solid mass 56 × 43 mm was found during ultrasound examination. Based on small pelvis MRI scan and hormonal finding, patient was qualified for laparotomy. During this procedure, the left salpingo-oophorectomy with removal of the tumor was performed. The histopathological examination identified SCT. During follow-up examination, one day after surgery, we found serum testosterone levels within normal ranges - 0.74 ng/ml (normal range 0.08-0.82 ng/ml). This case shows that hormone-producing ovarian tumors are rare but very important clinical causes of severe hyperandrogenism.

In this work, the mechanism of the NO2 reaction with PEDOT-RGO composite film has been investigated via in situ Raman spectroscopy. Reduced graphene oxide (RGO), poly(3,4-ethylenedioxytiophene)-reduced graphene oxide (PEDOT-RGO) and poly(3,4-ethylenedioxytiophene)/ClO4− (PEDOT/ClO4−) films were fabricated using an electrodeposition method and used as resistance sensors of gaseous nitrogen dioxide. The experimental results indicate that NO2 causes overoxidation of the PEDOT polymer (PEDOT/ClO4− film) which leads to resistance increase and irreversible response. In contrast, the PEDOT-RGO response in the presence of NO2 is reversible. During short NO2 exposure, PEDOT from the PEDOT-RGO composite does not react to the gas but the presence of RGO in the PEDOT-RGO composite does not affect the overoxidation potential. It was found that the nitrogen dioxide reacts more readily to reduced graphene oxide, thus RGO “protects” the polymer against the adverse overoxidation process.

The results of ionic transport and structural measurements for the lanthanum orthoniobate doped by praseodymium are presented and discussed. The influence of calcium co-doping on these properties has also been analyzed. The results suggest the predominant protonic conductivity for the investigated system in the whole range of investigated temperatures. The influence of calcium co-doping on phase purity is analyzed.

The Y0.07Sr0.93Ti0.8Fe0.2O3-δ (YSTF) material was fabricated using three different synthesis methods: modified polymer precursor method (MPP), Pechini method and a solid state reaction method. It was applied as an anode catalytic material for biogas reforming in solid oxide fuel cells. Clear differences in the microstructure of fabricated catalytic layers were found, mainly with respect to a grain size and distribution of grains. This led to some differences in biogas diffusion through the layer as well as in an amount of active sites for a biogas reforming. Also different chemical stability of each compound was observed in the fuel cell operating conditions. The best long-term stability in biogas was found for a fuel cell with the YSTF_Pechini catalytic layer (sintered in air at 1100 °C for 2 h) and the lowest one for a fuel cell with the YSTF_MPP layer.

In this study, the effects of Cu-ion substitution on the densification, microstructure, and physical properties of LaCo0.4Ni0.6-xCuxO3-δ ceramics were investigated. The results indicate that doping with Cu ions not only enhances the densification but also promotes the grain growth of LaCo0.4Ni0.6-xCuxO3-δ ceramics. The Cu substitution at x ≤ 0.2 can suppress the formation of La4Ni3O10, while the excess Cu triggers the formation of La2CuO4.032 phase. The p-type conduction of LaCo0.4Ni0.6O3-δ ceramic was significantly raised by Cu substitution because the acceptor doping ( C u N i ' ) triggered the formation of hole carriers; this effect was maximized in the case of LaCo0.4Ni0.4Cu0.2O3-δ composition (1480 S cm−1 at 500 °C). Thermogravimetric data revealed a slight weight increase of 0.29% for LaCo0.4Ni0.4Cu0.2O3-δ compact up to 871 °C; this is due to the incorporation of oxygen that creates metal vacancies and additional h • carriers, partially compensating the conductivity loss due to the spin-disorder scattering. As the temperature of the LaCo0.4Ni0.4Cu0.2O3-δ compacts rose above 871 °C, significant weight loss with temperature was observed because of the release of lattice oxygen to the ambient air as a result of Co (IV) thermal reduction accompanied by the formation of oxygen vacancies. A solid oxide fuel cell (SOFC) single cell with Sm0.2Ce0.8O2-δ (electrolyte) and LaCo0.4Ni0.4Cu0.2O3-δ (cathode) was built and characterized. The Ohmic (0.256 Ω cm2) and polarization (0.434 Ω cm2) resistances of the single cell at 700 °C were determined; and the maximum power density was 0.535 W cm−2. These results show that LaCo0.4Ni0.4Cu0.2O3-δ is a very promising cathode material for SOFC applications.

In this study, micro-tubular solid oxide fuel cells (T-SOFCs) with extruded La0.8Sr0.2Ga0.8Mg0.2O3-δ (LSGM) electrolyte as the mechanical support and LaCo0.4Ni0.6O3-δ (LCNO) or LaCo0.4Ni0.4Cu0.2O3-δ (LCNCO) as cathodes were prepared and characterized. Partial substitution of Cu for the Ni-ion positions in the LCNO lattices was found to significantly enhance the densification and accelerate the grain growth. The porosity-corrected electrical conductivity was significantly increased from 1275 S/cm for LCNO ceramic to 1537 S/cm for LCNCO ceramic, because the acceptor doping was compensated by the formation of hole carriers that produced additional polarons and significantly augmented the electrical conductivity. SOFCs with three configurations were built in this study, including Cell A that had a lanthanum-doped ceria (LDC) buffer layer inserted between the LSGM electrolyte and the LCNCO cathode, Cell B that used an LCNO-LSGM composite cathode, and Cell C that featured an LCNCO-LSGM composite cathode. Among the three cells, Cell C with 263 μm of LSGM electrolyte possessed the lowest Ohmic resistance of 0.89 Ω cm2, a polarization resistance of 0.69 Ω cm2, and the highest maximum power density of 178 mW cm−2 at 750 °C.

High-temperature reactions between glass–ceramic sealants and Fe-Cr alloy interconnects may lead to the formation of undesirable phases, and consequently degradation of solid oxide fuel/electrolyser devices. In this work, three different glass–ceramic sealants (Na-containing, Ba-containing, Sr-containing compositions) and Fe22Cr stainless steel powders (raw and pre-oxidised) are considered in order to test their chemical reactivity at 750 °C and 850 °C for 500 h in static air. The novelty of this approach is related to the use of powder mixtures instead of studying the reactivity on planar interfaces, which allows a better evaluation the materials’ reactivity. Oxidation tests indicate that the Sr-containing glass–ceramic/steel couple is the least reactive among the aged samples. For the Ba-containing samples, the formation of an undesirable phase of BaCrO4 is observed by diffractometry and photoelectron spectroscopy analyses. The present research explores, for the first time, the effects of exposing the high surface area of the alloy powder and glass–ceramic sealant interface, assessed by oxidation testing and microstructural analysis. The results show that by using mixed powders with large interface surface areas, degradation of the materials can be observed after relatively short times, allowing accelerated screening of the reactivity of materials, and thus their further development.

In this work, the influence of the electropolymerization temperature on corrosion, morphological and electrical properties of polypyrrole (PPy) film is studied. Polypyrrole is electrochemically synthesized on iron in the presence of sodium salicylate. The X-ray diffraction and scanning electron microscopy are performed in order to study the structure and morphology of electrodeposited PPy. The electroactive surface area, corrosion performance and resistance of the PPy film on iron are also investigated as a function of electropolymerization temperature. The results show that the synthesis temperature significantly affects the properties of the PPy film on iron. It is observed that at 25 °C amorphous PPy is formed, whereas lowering the temperature leads to the formation of a film containing crystallites of salicylic acid. The latter reveals lower corrosion protection and a much higher level of resistance compared to the amorphous one. These characteristics were associated with the presence of insulating salicylic acid crystals in the layer structure.