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Infiltration is a method, which can be applied for the electrode preparation. In this paper oxygen electrode is prepared solely by the infiltration of La0.6Sr0.4Co0.2Fe0.8O3‐δ (LSCF) into Ce0.8Gd0.2O2-δ (CGO) backbone. The use a polymer precursor as an infiltrating medium, instead of an aqueous nitrate salts solution is presented. It is shown that the polymer forms the single-phase perovskite at 600 °C, contrary to the nitrates solution. As a result, obtained area specific resistance (ASR) is lowered from 0.21 Ω cm2 to 0.16 Ω cm2 at 600 °C. More than 35% of LSCF in the oxygen electrode decreases the performance.

This work presents a simple and fully electrochemical route for the polymerization of poly(3,4-ethylenedioxytiophene) (PEDOT) films for fabricating a NO2 gas sensor prepared by electropolymerization of 3,4-Ethylenedioxythiophene (EDOT) monomer in lithium perchlorate/acetonitrile solution. The main aim of this study is to determine the sensing properties of conductive polymer at elevated temperatures. The effects of the humidity, working temperature and sensing response of the PEDOT to environmental gases are investigated. The use of the PEDOT film as NO2 gas meter of total flow of NO2 is evaluated.

The degradation of polypyrrole (PPy) coated iron is studied in phosphate buffer saline solution at 37 °C by odd random phase multisine electrochemical impedance spectroscopy (ORP-EIS). PPy is electropolymerized with anti-inflammatory salicylates incorporated in the film, as a drug release system. The modelling of EIS over time provides the quantitative description of the corrosion behaviour of the material. Thus, the reliable analysis of the degradation stages of PPy coated iron is attained. The outcome of the present study shows that the degradation of iron can be tailored by tuning the properties of the PPy coating for possible medical applications.

Ovarian cancer is the eighth most common cancer and the seventh highest cause of cancer-associated mortality in women worldwide. It is the second highest cause of mortality among female reproductive malignancies. The current standard first-line treatment for advanced ovarian cancer includes a combination of surgical debulking and standard systemic platinum-based chemotherapy with carboplatin and paclitaxel. Although a deeper understanding of this disease has been attained, relapse occurs in 70% of patients 18 months subsequent to the first-line treatment. Therefore, it is crucial to develop a novel drug that effectively affects ovarian cancer, particularly tumors that are resistant to current chemotherapy. The aim of the present study was to identify genes whose expression may be used to predict survival time or prognosis in ovarian cancer patients treated with chemotherapy. Gene or protein expression is an important issue in chemoresistance and survival prediction in ovarian cancer. In the present study, the research group consisted of patients treated at the Surgical Clinic of the Gynecology and Obstetrics Gynecological Clinical Hospital, Poznan University of Medical Sciences (Poznan, Poland) between May 2006 and November 2014. Additional eligibility criteria were a similar severity (International Federation of Gynecolgy and Obstetrics stage III) at the time of diagnosis, treatment undertaken in accordance with the same schedule, and an extremely good response to treatment or a lack of response to treatment. The performance of the OncoScan® assay was evaluated by running the assay on samples obtained from the four patients and by following the recommended protocol outlined in the OncoScan assay manual. The genomic screening using Affymetrix OncoScan Arrays resulted in the identification of large genomic rearrangements across all cancer tissues. In general, chromosome number changes were detected in all examined tissues. The OncoScan arrays enabled the identification of ~100 common somatic mutations. Chemotherapy response in ovarian cancer is extremely complex and challenging to study. The present study identified specific genetic alterations associated with ovarian cancer, but not with response for treatment.

Oxygen electrodes prepared by infiltration of yttria stabilized zirconia backbone with Ce 0.8 Gd 0.2 O 1.95 barrier layer and LaNi 1-x Co x O 3-δ (x = 0.4 to 0.7) catalyst for application in reversible solid oxide cells have been studied. The effect of temperature and Ni:Co ratio on their phase composition, microstructure and electrochemical properties are discussed. It was shown that oxygen electrodes infiltrated with LaNi 0.5 Co 0.5 O 3-δ had the lowest polarization resistance, i.e. 67 mΩ cm 2 at 600 °C. The performance of a fuel electrode supported solid oxide cell with infiltrated oxygen electrode in both fuel cell and electrolysis mode was tested. Electrochemical characterization of the solid oxide cell showed that the resistance contribution from these oxygen electrodes to the overall cell resistance is minor i.e. approximately 20 mΩ cm 2 at a temperature of 700 °C. The cell was also tested in the steam electrolysis mode at a constant current of −1.0 A cm −2 at 800 °C for 240 h. The oxygen electrode showed reasonable degradation rate with the oxygen electrode resistance of 33 mΩ cm 2 at 700 °C after 240 h of testing.

Many of the challenges in solid oxide fuel cell technology stem from chemical and mechanical incompatibilities between the anode, cathode and electrolyte materials. Numerous attempts have been made to identify compatible materials. Here, these challenges are circumvented by the introduction of a working single layer fuel cell, fabricated from a composite of proton conducting BaCe0.6Zr0.2Y0.2O3-δ and a mixture of semiconducting oxides – Li2O, NiO, and ZnO. Structural and electrical properties of the composite, related to its fuel cell performance are investigated. The single layer fuel cell shows a maximum OCV of 0.83 V and a peak power density of 3.86 mW cm−2 at 600 °C. Activation and mass transport losses are identified as the major limiting factor for efficiency and power output.

Perovskite La0.6Sr0.4Co0.2Fe0.8O3 − δ (LSCF) is often used as a cathode material for solid oxide fuel cells (SOFC) due to high mixed ionic and electronic conductivity and good catalytic activity. Unfortunately, sintering of the LSCF cathode together with the yttria stabilized zirconia (YSZ) electrolyte, leads to formation of the La2Zr2O7 and SrZrO3 phases in the interface. These phases increase the resistance of the cell. To avoid creation of the undesirable phases, diffusion barrier layers are often used. In this work 200 nm thick cerium-gadolinium oxide (CGO) layer deposited by spray pyrolysis is used as a diffusion barrier. The impact of sintering temperature on the effectiveness of diffusion barrier was examined. For optimized sintering temperature of 900 °C, the CGO barrier layer leads to lowering polarization loses of almost two orders of magnitude from 477 mΩ cm2 (when CGO is not used) to 7 mΩ cm2.

Gadolinium doped ceria (Ce 0.8 Gd 0.2 O 2 − x -CGO) layer fabricated by spray pyrolysis is investigated as the diffusion barrier for solid oxide fuel cell. It is deposited between the La 0.6 Sr 0.4 FeO 3 − δ cathode and the yttria stabilized zirconia electrolyte to mitigate harmful interdiffusion of elements. The parameters of the fabrication process are linked to the measured area specific resistances of the symmetrical cells and the efficiency of the fuel cells. Results show, that application of 800 nm thick barrier effectively hinder negative reactions, while 400 nm thick layer is sufficient to prevent degradation of the Ohmic resistance.

The paper presents recent advances in Poland in the field of high temperature fuel cells. The achievements in the materials development, manufacturing of advanced cells, new fabrication techniques, modified electrodes and electrolytes and applications are presented. The work of the Polish teams active in the field of solid oxide fuel cells (SOFC) and molten carbonate fuel cell (MCFC) is presented and discussed. The review is oriented towards presenting key achievements in the technology at the scale from microstructure up to a complete power system based on electrochemical fuel oxidation. National efforts are covering wide range of aspects both in the fundamental research and the applied research. The review present the areas of (i) novel materials for SOFC including ZrO2-based electrolytes, CeO2-based electrolytes, Bi2O3 based electrolytes and proton conducting electrolytes, (ii) cathode materials including thermal shock resistant composite cathode material and silver-containing composites, (iii) anode materials, (iv) metallic interconnects for SOFC, (v) novel fabrication techniques, (vi) pilot scale SOFC, including electrolyte supported SOFC (ES-SOFC) and anode supported SOFC (AS-SOFC), (vii) metallic supported SOFC (MS-SOFC), (viii) direct carbon SOFC (DC-SOFC), (ix) selected application of SOFC, (x) advances in MCFC and their applications, (xi) advances in numerical methods for simulation and optimization of electrochemical systems.

In this work, novel functional layers were prepared by a low temperature spray pyrolysis method on the oxygen side of the solid oxide cells. Thin layers of Ce0.8Gd0.2O2 and LaNi0.6Fe0.4O3 are prepared between the electrolyte and the porous oxygen electrode. Additionally the influence of the sprayed ceria barrier layer on the zirconia based electrolyte with the new layers is evaluated. Impedance spectroscopy results show improvement in contact between the electrolyte and the porous cathode electrode. Additionally, electrochemical performance of the cathode is improved, as evidenced by a lowered area specific resistance and increased power density obtained from an anode supported cell employing the new layer.

Recently, it was shown that thin functional layers introduced between an electrolyte and cathode might improve cathode performance. However, the mechanism of this improvement still needs analysis. In this paper, a thin (∼140 nm), spin-coated perovskite layer (La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3-δ ) was placed between a cathode (La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3-δ ) and an electrolyte (Ce 0.8 Gd 0.2 O 2-δ ) and the effects of this investigated. The microstructure of this layer was varied in order to determine its impact on the electrical and electrochemical properties. It has been shown that a mesoporous, nanocrystalline layer increases the active area for oxygen reduction and charge transfer through the cathode/electrolyte interface, which improves performance. Moreover, the stability of the cathode from thermal stresses is increased. In contrast, the coarsening of the grain and the layer densification has a reduced impact on the cathode performance.

In this study two materials, MnCo 2 O 4 and MnCo 1.8 Fe 0.2 O 4 are studied as potential protective coatings for Solid Oxide Fuel Cell interconnects working at 750 °C. First powder fabrication by a modified Pechini method is described followed by a description of the coating procedure. The protective action of the coating applied on Crofer 22 APU is evaluated by following the area specific resistance (ASR) of the scale/coating for 5500 h including several thermal cycles. The coating is prepared by brush painting and has a porous structure after deposition. Post mortem microstructural characterization performed on the coated samples shows good protection against chromium diffusion from the chromia scale ensured by a formation of a dense reaction layer. This study shows, that even without high temperature sintering and/or reactive sintering it is possible to fabricate protective coatings based on MnCo spinels.

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.

Low-temperature deposition of electroceramic thin films allows the construction of new devices and their integration with existing large-scale fabrication methods. Developing a suitable low-cost deposition method is important to further advance the development of microdevices. In this work, we deposited a 1-μm-thick La0.6Sr0.4CoO3−δ (LSC) perovskite with high electrical conductivity on sapphire substrates at 400°C and analyzed its electrical, morphological and structural properties as a function of temperature in the range of 400–1100°C. The results show that spray pyrolysis can be used to deposit high-quality reproducible layers with the desired chemical and phase composition. Upon heating to around 600°C, the residual C–O and C=O species are removed, and the deposited layers crystallize and become conducting. The dependence of electrical conductivity versus processing temperature has a complex character—the maximum conductivity is found for layers processed at 800°C. An analytical model of stress distribution was used to predict stress to which the bi-layer material would be exposed to while being cooled down from the annealing temperature to room temperature. The high electronic conductivity and high-quality microstructure of the LSC layers, which can be adjusted with the appropriate heat treatment procedure, make them suitable for applications in electrochemical devices applied in integrated energy modules, including electrodes or contacts.

Intermediate temperature solid oxide fuel cells oxygen electrodes are modified by active interfacial layers. Spray pyrolysis is used to produce thin (≈500 nm) layers of mixed ionic and electronic conductors: Sm0.5Sr0.5CoO3−δ (SSC), La0.6Sr0.4CoO3−δ (LSC), La0.6Sr0.4Co0.2Fe0.8O3−δ (LSCF), and Pr6O11 (PrOx) on the electrode–electrolyte interface. The influence of the annealing temperature on the electrode polarization (area specific resistance—ASRpol) is investigated by impedance spectroscopy of symmetrical electrodes in the temperature range of 400–700 °C. The results show that the introduction of nanocrystalline interlayers promotes an oxygen reduction reaction by extending the active surface area and improved contact between the electrode and the electrolyte. Introducing LSCF, LSC, or SSC interlayer reduces ASRpol by a factor of 4 and PrOx by a factor of 2 against the reference, powder processed LSCF electrode. At 600 °C, the obtained ASRpol values for PrOx, LSCF, LSC, and SSC interlayer are 245, 137, 119, and 107 mΩ cm2, which can be considered very low in comparison to standard powder processed oxygen electrodes. Anode supported single cell with developed LSC/LSCF electrode reveals ≈1.2 W cm−2 power output at 600 °C and maintains stable cell voltage of 0.75 V under 1 A cm−2 during 60 h of the test.

In this study, the influence of La content on the characteristics of Nb-, Mo-, and W-doped LaxGe6O26±δ electrolytes was investigated through sintering study, X-ray diffraction, scanning electron microscopy, and conductivity measurement. The densification of LaxGe5.5Nb0.5O26±δ and LaxGe5.5W0.5O26±δ was retarded as the x reached 9.75, while that of LaxGe5.5Mo0.5O26±δ improved with increasing La content. The average grain size slightly increased and weight loss due to evaporation of GeO2 significantly reduced with increasing La content, ranging from 1.39% to 0.26%. Among the systems studied, La9.33Ge5.5Nb0.5O26.245, La9.33Ge5.5Mo0.5O26.045, and La9.50Ge5.5W0.5O26.75 electrolytes revealed great potential for use in SOFC applications.

In this work, electrosynthesis of electroactive, 3D nano-/micro-structured porous polypyrrole film is presented. The PPy film was synthesized potentiostatically in a one-step process from aqueous solution of pyrrole and lithium perchlorate. The growth mechanism of such structure included: the formation of typical globular PPy film, followed by the formation of the PPy fibers, which then took part in the formation of 3D highly porous PPy structures. Preliminary studies show that such PPy film is a very good candidate as a sensing material for glucose biosensor. It exhibits very high sensitivity (28.5 mA mM−1 cm−2) and can work without any additional dopants, mediators or enzymes.

In this work electrochemical stability of optimized PPy film on iron in aqueous solution of sodium salicylate is studied. The main drawback of conducting polymers is their possibility to undergo an irreversible degradation (overoxidation). The overoxidized polymers lose their properties, for example, conductivity and redox activity, what excludes them from some practical applications. This study demonstrates that lowering the concentration of salicylate in the electrolyte increases the electrode potential, at which overoxidation of PPy begins. It widens the electrode potentials, within which such a polymer can be used. Moreover, it is evidenced that even though the electrolyte concentration is lowered, the redox activity and the electrical properties of the PPy film are retained.

Several solutions of ionic liquids based on 1-ethyl-3-methylimidazolium cation saturated and unsaturated with carbon dioxide were prepared and characterized by electrochemical impedance spectroscopy. The influence of ILs saturation on its electrical conductivity was determined. Additionally, the influence of the water presence and variations of temperature on electrical properties of ionic liquids were investigated. Changes of conductivity due to saturation and water content are discussed. Obtained results show that the ionic liquids conductivity significantly depends on the water content. It was shown that the increase of the conductivity cannot be explained by partial conductivities of hydronium, bicarbonate and hydroxide ions.

This work presents a simple and fully electrochemical route used for fabricating of a NO2 gas sensor made of reduced-graphene-oxide-poly(3,4-ethylenedioxythiophene) composite film. The sensing platform was fabricated from alumina substrate and equipped with gold interdigitated electrodes and built-in heater. The temperature distribution on the surface of interdigitated electrodes was investigated by a thermal imaging camera and compared with numerical simulations. The sensing film was prepared on sensing platform by electropolymerization of EDOT monomer and graphene oxide solution and reduction in 0.1 M KCl. A scanning electron microscopy and Raman spectroscopy of the sensing film were performed. Gas sensing measurements were carried out at elevated temperatures. The effects of the operating and annealing temperature of the gas sensing film to NO2 on the sensing performance were investigated. The response characteristics in NO2 at elevated temperatures in a tube furnace and using a built-in heater were compared. The effect of the flow rate and relative humidity was also investigated.

Widespread commercialization of solid oxide fuel cells requires lowering its cost. It is generally accepted that to lower the cost of solid oxide fuel cells it is necessary to use metal alloys as interconnectors and, consequently, lower its operating temperature to slow down interconnectors degradation. As a result the area specific resistance of the cathodes should be lowered to sustain the performance of the cells. In order to slow the interconnectors degradation (due to corrosion and interdiffusion with the anode) and improve the performance of the cathodes, novel functional layers are introduced to the structure of the fuel cells. In this paper, results related to three kinds of functional layers will be presented: a thin cathode layer between the porous cathode layer and the electrolyte to improve the cathode performance, a buffer layer between the electrolyte and the cathode to slow down inter-diffusion of atoms and thin and dense interconnector coatings to slow down interconnectors degradation. The investigated layers are deposited by cost effective spin coating and spray pyrolysis methods. Introduction of the layers show positive and promising results.

The Hebb–Wagner polarization method with the electron blocking electrode has been discussed in this paper in aim to determine a partial ionic conductivity of Sr-doped lanthanum manganite. The “limiting current” in the proposed system was measured using the two-point DC technique with additional Pt electrode between LSM and blocking electrode. The electrochemical model based on bulk diffusion processes and Boltzmann statistics has been also described. The ionic conductivity calculated with the use of proposed model for La 0.7 Sr 0.3 MnO 3+ δ was 5.3×10 −4 S cm −1 at 800 °C and the activation energy of ionic conductivity was found to be (0.60±0.02) eV. This result is in agreement with previous literature reports and indicates the workability of the modified Hebb–Wagner system.

This study describes the ultrasound diagnostic process and management in a patient with a unique, rare form of fibroids, i.e. the atypical variant. According to the WHO definition, an atypical uterine myoma cannot be histologically unambiguously diagnosed as benign or malignant. Atypical leiomyomas are characterized by moderate or high quantity of pleomorphic atypical tumor cells, with a small number of mitotic divisions and lack of coagulative necrosis in the tumor. They have a low rate of extrauterine, intraabdominal recurrence, with a negligible risk for distant metastases. Due to the fact the atypical variant of leiomyomas is very rare, it presents a significant diagnostic challenge for obstetricians. The most reliable diagnosis can be made only on the basis of the histopathological examination. In this paper, we present a case of a patient in whom an echo with the diameter of 92 mm and a heterogeneous echogenicity with visible anechoic fields were discovered in the uterine fundus. HD color Doppler demonstrated high vascularization within the tumor, peripherally as well as centrally. The peripheral and central vascularization was rated at 4/4 points on a scale by Exacoustos. The tumor in the uterus met the criteria of high probability of malignancy i.e. 8 points on the vascular scale (power Doppler scale ≥ 7 pts.), solid tumor and a size over 8 cm. Blood flow velocity and vascular resistance in the tumor vessels were evaluated (PSV - 5.76 cm/s, ED - 3.16 cm/s, RI - 0.45 S / D - 1.82). Blood flow in the tumor presented low resistance. Hysterectomy without oophorectomy, with an intraoperative histopathological examination, was performed, and a fibroid was confirmed. The tumor was soft, yellow, with small and medium level of dispersed atypia in microscopic examination. There was no necrosis or mitotic figures. The histopathological image confirmed the atypical leiomyoma of low risk of recurrence. Atypical fibroids are rare in gynecological oncology and they do not have the characteristic clinical course. Furthermore, they do not show the typical characteristics during imaging studies, including ultrasound screening, Sometimes, due to the sonographic image, they should be differentiated from sarcomas. Also, it is necessary to exclude malignancy because of their ambiguous histological characteristics.

The results of ionic transport measurements for the lanthanum orthoniobate substituted with 10 and 30 mol% of antimony (LaNb0.9Sb0.1O4 and LaNb0.7Sb0.3O4) are presented and discussed. The influence of calcium co-doping on these properties has also been analysed. It has been shown that for the investigated material protonic conductivity predominates at temperatures up to 800 °C in oxidizing atmospheres under wet conditions. The maximum observed protonic conductivity reaches ∼10−4 S cm−1 at 800 °C (in humidified air); under dry conditions, the increasing influence of oxygen vacancies and holes is detected. Oxygen self-diffusivity has also been analysed by isotopic exchange to investigate the possible diffusion paths.

In this work, the influence of the synthesis conditions on the structure, morphology, and electrocatalytic performance for the oxygen evolution reaction (OER) of Mn-Co-based films is studied. For this purpose, Mn-Co nanofilm is electrochemically synthesised in a one-step process on nickel foam in the presence of metal nitrates without any additives. The possible mechanism of the synthesis is proposed. The morphology and structure of the catalysts are studied by various techniques including scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and transmission electron microscopy. The analyses show that the as-deposited catalysts consist mainly of oxides/hydroxides and/or (oxy)hydroxides based on Mn2+, Co2+, and Co3+. The alkaline post-treatment of the film results in the formation of Mn-Co (oxy)hydroxides and crystalline Co(OH)2 with a &beta, phase hexagonal platelet-like shape structure, indicating a layered double hydroxide structure, desirable for the OER. Electrochemical studies show that the catalytic performance of Mn-Co was dependent on the concentration of Mn versus Co in the synthesis solution and on the deposition charge. The optimised Mn-Co/Ni foam is characterised by a specific surface area of 10.5 m2&middot, g&minus, 1, a pore volume of 0.0042 cm3&middot, 1, and high electrochemical stability with an overpotential deviation around 330&ndash, 340 mV at 10 mA&middot, cm&minus, 2geo for 70 h.

Iron doped strontium titanates (SrTi1-xFexO3-δ) are an interesting mixed ionic-electronic conductor model used to study basic oxygen reduction/oxidation reactions. In this work, we performed an impedance spectroscopy study on symmetrical porous SrTi0.30Fe0.70O3-δ (STF70) electrodes on a ceria-based electrolyte. The sample was measured in varying oxygen concentration: from 0.3% to 100% in 800 °C–500 °C temperature range. Low polarisation resistance (e.g.

This work evaluates electrodeposited and differently treated Mn-Co catalysts for their oxygen evolution reaction activity. Catalysts are evaluated in the as-deposited and heat treated state: after 350 °C and 600 °C. Results show that the highest electrochemical activity is obtained for the as-deposited Mn-Co oxyhydroxide, which possibly possess a layered double hydroxide structure. After the heat treatment process, especially after 600 °C, the electrochemical performance decreases considerably.

In this work, the potentiostatic electropolymerization of polypyrrole (PPy) on iron in aqueous solution of sodium salicylate and pyrrole is studied in situ by odd random phase electrochemical impedance spectroscopy (ORP-EIS). The influence of the pyrrole concentration on the electrosynthesis process is investigated. The ORP-EIS technique ensures a reliable analysis of the PPy electrosynthesis on iron by means of an advanced data analysis of the non-linear and non-stationary behaviour and the signal-to-noise ratio of the system. Additionally, the structure and the chemical nature of the PPy film on iron are studied by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX) and glow discharge optical emission spectroscopy (GDOES). The results of the characterization confirm the presence of the passivation layer at the PPy/iron interface formed prior to the polymer deposition. The modelling of the impedance evolution over time provides the quantitative analysis of the electropolymerization of PPy on iron. The results show that the electrosynthesis of pyrrole on oxidizable iron in the presence of sodium salicylate is a complex process, which includes not only the pyrrole oxidation reactions but also reactions such as the oxidation/reduction of the iron surface and/or reactions between the iron, formed interlayer and polypyrrole.

Air pollution is a growing concern of civilized world, which has a significant impact on human health and the environment. Recent studies highlight that the exposure to polluted air can increase the incidence of diseases and deteriorate the quality of life. Hence, it is necessary to develop tools for real-time air quality monitoring. For air pollution monitoring a wide range of stationary gas and particulate analysers can be used. However, such instruments are relatively large, heavy and expensive. Only governments, local authorities and major industries can afford to use such devices. Instruments based on low cost gas sensors can be interesting and promising alternative. However, real-life usage of gas sensors in monitoring outdoor air is connected with several challenges, such as temperature or humidity changes affecting sensor response. In this study, a laboratory evaluation of commercially available electrochemical gas sensors for the monitoring of CO in ambient air is presented. Six commercial electrochemical CO sensors were tested simultaneously under controlled gas concentrations and various environmental conditions.

Air pollution is a one of the major concern of civilized world, which has a significant impact on human health and the environment. Recent studies highlight that the exposure to polluted air can increase the incidence of diseases and deteriorate the quality of life. Hence, it is necessary to develop tools for real-time air quality monitoring. Electronic-nose systems based on sensors are an interesting and promising technology in the field of monitoring environmental pollution. However, real-life usage in monitoring of outdoor air is connected with several challenges, such as temperature or humidity changes affecting sensor response. In this study, a performance of the three electronic nose systems based on semiconducting gas sensors only, amperometric gas sensors only and both type of sensors in outdoor air quality is evaluated. Toxic gas concentration prediction ability of these three e-noses is compared with the reference results from the stationary station of air monitoring system.

The aim of the study was to evaluate whether it is possible to extract the information about the gas concentration despite the influence of humidity. Commercial semiconductor sensor response was examined under the application of a periodic temperature change. The data was collected using measurement protocol for different concentrations of ammonia at specified levels of relative humidity. In this work we focused on the evaluation of the Discrete Wavelet Transform analysis results obtained during experimental investigation of the single semiconductor gas sensor in the presence of humidified atmosphere containing ammonia. The results of the analysis show that proposed method enable the possibility of determine the low concentrations of ammonia.

In this work the effects of electropolymerization conditions on the morphological properties and conductivity of poly(3,4-ethylenedioxythiophene) (PEDOT) film have been studied. PEDOT films were electrochemically synthesized in a one step process from acetonitrile solution containing 3,4-ethylenedioxythiophene (EDOT) and lithium perchlorate. Based on atomic force microscopy, scanning electron microscopy, cyclic voltammetry and impedance spectroscopy measurements, the morphological properties such as the of structure, double layer capacitance and thus the polymer surface area have been determined. It was shown that depending on the deposition conditions applied, different structures and film surface area could be obtained. Impedance measurements performed during deposition showed different resistance behavior and conductivity. The relationship between structure and conductivity of PEDOT film obtained under different deposition conditions has been discussed.

Molten salt synthesis method has been used to prepare the single phase magnesium doped lanthanum orthoniobate. The phase composition has been checked by X-ray diffraction method and the microstructure studies have been performed by scanning electron microscopy. The high temperature properties of the material have been investigated by thermogravimetry and electrochemical impedance spectroscopy. A dependence between sample total conductivity and temperature has been found supporting the thesis that there is strong correlation between apparent activation energy of conductivity and structural phase transition at ~500 °C. It has been also shown that the conductivity of magnesium doped lanthanum orthoniobate synthesized by the molten salt route reaches values of ~1 mS/cm at 720 °C in wet hydrogen.

In this paper, thin perovskite layers between cathode material of solid oxide fuel cells and gadolinia-doped ceria buffer layer are investigated. Thin layers made of LaNi0.6Fe0.4O3-δ (LNF), La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCF), or SrTi0.65Fe0.35O3-δ (STF) were symmetrically deposited by spin coating method from metallo-organic polymer precursors on a Ce0.8Gd0.2O2-δ (CGO) substrate. Porous and about 40-μm-thick LNF cathodes were deposited on both sides of the substrate and sintered at 1100 °C. Different thicknesses of the thin perovskite layer were investigated in order to find the most effective one and to better understand its influence on the cathode/electrolyte interface. It was found that approximately 150 nm LNF or LSCF layer is sufficient to minimize interface resistance and improve cathode reproducibility. It was concluded that the thin perovskite layer increases contact area and improves the oxygen ion transport between the cathode and electrolyte without influencing the ox- ygen reduction reaction mechanism.

In this paper solid oxide fuel cells operating with dry synthetic biogas have been examined. In order to increase their stability the layers of CuO-CeO 2 , Cu 1.3 Mn 1.7 O 4 and Y 0.08 Sr 0.92 Ti 0.8 Fe 0.2 O 3 -δ have been deposited on the Ni-YSZ anode site. These layers should catalyze the internal biogas reforming and prevent the carbon deposition on the anode site. It has been found that CuO-CeO 2 and Cu 1.3 Mn 1.7 O 4 catalysts led to an increase of the stability (at least 7 days) of the fabricated fuel cells powered by biogas, whereas the unmodified fuel cell, as well as the fuel cell with Y 0.08 Sr 0.92 Ti 0.8 Fe 0.2 O 3 -δ catalyst degraded gradually with time. A significant amount of carbon nanofibers has been formed on the catalyst surface after fuel cell test. However, they have not formed in the anode area. The use of CuO-CeO 2 and Cu 1.3 Mn 1.7 O 4 catalysts prevented the carbon deposition on the anode site, and thus the fuel cell degradation was slower when operating with biogas fuel.

In this work corrosion kinetics of the porous IN625 alloy is studied in the temperature range of 700 °C–800 °C in air and humidified hydrogen for up to 1000 h. Moreover, an effective and simple method of reducing corrosion rates of porous alloys by the infiltration of the rare earth elements is shown. Modification by the yttrium containing precursor reduces the corrosion rate by a factor of 50 in air at 700 °C so that the lifetime of the infiltrated alloy is greatly extended.

Objectives: The aim of this study was to assess the sensitivity and specificity of HE4 in detecting and differentiating between types I and II epithelial ovarian cancer (EOC) in comparison with CA125. Material and methods: We measured HE4 and CA125 serum concentrations in 206 samples taken from patients operated in Gynecologic Oncology Department due to ovarian tumors. Ovarian cancer was confirmed in 89 cases divided into type I and type II. 52 healthy patients without any gynecological disease formed the control group. The sensitivity and specificity for type I and type II EOC detection and differentiating between both types was evaluated for HE4 and CA125. Results: The HE4 and CA125 serum concentrations were significantly higher in type II than in type I EOC (p=0.008696, p=0.000243 respectively).The HE4 and CA125 sensitivity for type I and benign tumors differentiation was 63.16% for both of them and specificity was 87.29% vs 67.89% respectively. For CA125 these differences did not reach statistical significance. The HE4 sensitivity and specificity for type II and benign tumors differentiation were 87.14% and 96.61%, respectively, and for CA125 these values were 82.86% and 94.07%, respectively. Conclusions: Pretreatment analysis of HE4 serum concentration is superior to CA125 in differential diagnosis of ovarian cancer subtypes (I and II). HE4 is superior to CA125 in detecting ovarian cancer type II. Neither HE4 nor CA125 is an effective diagnostic tool for type I ovarian cancer detection. A new highly specific and highly sensitive tumor marker for type I EOC is needed.

The practical application of human nose for fragrance recognition is severely limited by the fact that our sense of smell is subjective and gets tired easily. Consequently, there is a significant need for an instrument that can be a substitution of the human sense of smell. Development of an electronic nose devices is an active area of research starting from pioneering research of Dodd and Persuad in the mid-1980s. Such systems are used in growing number of applications. They comprise an array of several electrochemical gas sensors with partial specificity and a pattern recognition algorithms. Since most of the existing types of sensors are characterized by low selectivity, they can all be used in the construction of electronic noses. Most electronic nose systems are based only on one type of gas sensors. However, different types of sensors have different advantages and disadvantages. In this article, an electronic nose system for the purpose of incorporating different types of sensors has been proposed developed. Such approach allows to benefit from advantages of different type of sensors, and thus improve the operation of the entire system.

Electronic gas recognition systems, in literature commonly referred as electronic noses, enable the recognition of a type and a concentration of various volatile compounds. Typical electronic gas-analyzing device consists of four main elements, namely, gas delivery subsystem, an array of gas sensors, data acquisition and power supply circuits and data analysis software. The commercially available metal-oxide TGS sensors are widely used in such instruments. They are inexpensive and considered to be reliable. However, such sensors also have limitations. One of the most important problems of utilization of TGS sensors is the drift of their responses. It can lead to incorrect interpretation of the results of measurements. This can be a serious problem in the systems, which are designed to detect e.g. harmful gases. Drift can be caused by poisoning or aging of sensor as well as by the influence of temperature, humidity and gas flow rate. There are approaches to mitigate of this effect. One of them is based on the design of the proper data analysis procedures and algorithms. In this work the method of features extraction from continuous measurements of temperature modulated TGS sensor is presented. Namely, the voltage applied to the sensor heater is switched between two values, while the gas flow rate of the measurement cell is maintained constant. The presented method enables the extraction of the features at any time of measurements using time window with the fixed width. The calibration using LS-SVM regression is utilized for the purpose of prediction of ammonia concentration in humidified atmosphere. The validation measurements were conducted two weeks after the calibration procedure.

Impedance spectroscopy is one of the most commonly performed measurements to characterize electronic and electrochemical systems. Impedance spectra have limited resolution and many different processes may overlap what could be the reason of obstructions in its proper later analysis. Up to date, there are three approaches to solve this problem: examining impedance spectra itself, fitting spectra with equivalent circuits, and calculating the distribution of relaxation times (DRT). The latter method does not require any model or further knowledge about the system. As a result of DRT calculation, a plot containing relatively narrow peaks related to relaxation process of measured system is obtained. Namely, the position of the peak is related to time constant of the process, while the area under the peak to relaxation resistance. The aim of this work is to test available fitting functions to calculate area under a peak for previously prepared model containing different equivalent circuit elements. Obtained results are validated using exact formulas describing distribution of relaxation times for mentioned elements.

Ovarian hyperthecosis (OH) is characterized by the presence of abundant luteinized theca cells in ovaries that secret androgen. It typically presents as severe hyperandrogenism and/or virilization in postmenopausal woman. Here we describe a 66-year old woman with presentation of severe hirsutism, alopecia, clitoromegaly and laboratory finding of significantly elevated serum total testosterone concentration and hyperinsulinemia. Performed imaging studies revealed normal sized, homogeneous ovaries, signs of endometrial hypertrophy and normal adrenal glands. Due to severe hyperandrogenemia and signs of endometrial hypertrophy, the total abdominal hysterectomy with bilateral salpingo-oophorectomy has been performed. Pathological examination revealed OH and endometrial hyperplasia. Androgenic activity of ovarian stromal cells has been confirmed using alpha-inhibin histochemical staining. Postmenopausal hyperandrogenemia is a diagnostic and therapeutic challenge and the imaging studies often may be misleading and require careful and critical consideration.

In this work, thin films (~1000 nm) of a pure MnCo2O4 spinel together with its partially substituted derivatives (MnCo1.6Cu0.2Fe0.2O4, MnCo1.6Cu0.4O4, MnCo1.6Fe0.4O4) were prepared by spray pyrolysis and were evaluated for electrical conductivity. Doping by Cu increases the electrical conductivity, whereas doping by Fe decreases the conductivity. For Cu containing samples, rapid grain growth occurs and these samples develop cracks due to a potentially too high thermal expansion coefficient mismatch to the support. Samples doped with both Cu and Fe show high electrical conductivity, normal grain growth and no cracks. By co-doping the Mn, Co spinel with both Cu and Fe, its properties can be tailored to reach a desired thermal expansion coefficient/electrical conductivity value.

The concentration or the partial pressure of oxygen in an environment can be determined using different measuring principles. For high temperature measurements of oxygen, ceramic-based sensors are the most practical. They are simple in construction, exploration and maintenance. A typical oxygen potentiometric sensor consists of an oxygen ion conducting solid electrolyte and two electrodes deposited on the two sides of the electrolyte. In this paper different structures of potentiometric oxygen sensors with a solid state reference electrode were fabricated and investigated. The fabricated structures consisted of oxygen ion conducting solid electrolyte from yttria stabilized zirconia, a sensing platinum electrode and nickel-nickel oxide reference electrode. The mixture of nickel-nickel oxide was selected as the reference electrode because it provides reliable electrochemical potential in contact with oxygen conducting electrolyte. To avoid oxidation of nickel the reference electrode is sealed from ambient and the mixture of nickel-nickel oxide was formed electrochemically from nickel oxide after sealing. The effectiveness of the sealing quality and the effectiveness of nickel-nickel oxide mixture formation was investigated by impedance spectroscopy.

A composite of BaCe0.6Zr0.2Y0.2O3–δ and Li2O:NiO:ZnO was investigated for fuel cell applications. The composite was successfully synthesized and its phase stability was confirmed at temperatures up to 900°C. The influence of sintering and pressing aids on density was also investigated. Electrical properties were measured. DC electrical conductivity was about 8•10-4 S/m at 845K. Open circuit voltage measurements in wet hydrogen have shown that the composite can be used in single layer fuel cells.