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Aims: To demonstrate how intensive management practices affect the belowground productivity of Moso bamboo, we examined the spatial distribution of fine root traits under three stands with high-intensity (T1, tillage plus biennial fertilization), low-intensity (T2, tillage plus quadrennial fertilization), and extensive (CK, no-tillage plus no fertilization) management, and evaluated the relationships among root traits and soil properties, aggregate stability (MWD). Methods: Bamboo fine root and soil samples were collected from three depths (0–10, 10–20, 20–30 cm) and three horizontal distances (20, 40, 60 cm) under three management strategies. Root biomass, root morphology, soil properties, and aggregate composition were determined. Results: Compared with CK, T1 and T2 had higher fine root biomass (FRB), and the largest FRB in the 10–20 cm soil layer. T1 had significantly higher allocation proportion of D1–2 class FRB and root length density (RLD) and significantly lower specific root length (SRL) and specific surface area (SSA). Vertically, intensive management led to an increase in FRB in the 10–20-cm soil layer and MWD in the 20–30-cm soil layer. Horizontally, FRB was highest at a distance of 20 cm from bamboo culm. A strong positive correlation was identified among FRB, RLD, and TP in each soil layer as well as among MWD, TP, and RLD. Conclusions: Intensive management promotes fine root growth with high length in response to more soil P content, and high-intensity management shifts the expression of root functional traits toward transport fine roots proportion and 10–20-cm soil layer, and facilitates aboveground productivity of Moso bamboo. TOC, TP, and RLD are the main three drivers correlated with soil aggregate stability. [ABSTRACT FROM AUTHOR]

Inflammasome activation is a crucial mechanism in inflammatory responses. Bax-interacting factor 1 (Bif-1) is required for the normal formation of autophagosomes, but its ability to exert an inflammatory regulatory effect remains unclear. The aim of the present study was to explore the role of Bif-1 in inflammation, possibly mediated through autophagy regulation. Using a lipopolysaccharide (LPS)/adenosine triphosphate (ATP)-induced inflammatory model in J774A.1 cells, the effect of Bif-1 on inflammasome activation and the underlying mechanisms involving autophagy regulation were investigated. Elevated levels of NLR family pyrin domain containing protein 3 inflammasome and interleukin-1β (IL-1β) proteins were observed in J774A.1 cells after LPS/ATP induction. Furthermore, Bif-1 and autophagy activity were significantly upregulated in inflammatory cells. Inhibition of autophagy resulted in inflammasome activation. Silencing Bif-1 expression significantly upregulated IL-1β levels and inhibited autophagy activity, suggesting a potential anti-inflammatory role of Bif-1 mediated by autophagy. Additionally, inhibition of the nuclear factor-κB (NF-κB) signaling pathway downregulated Bif-1 and inhibited autophagy activity, highlighting the importance of NF-κB in the regulation of Bif-1 and autophagy. In summary, the current study revealed that Bif-1 is a critical anti-inflammatory factor against inflammasome activation mediated by a mechanism of autophagy regulation, indicating its potential as a therapeutic target for inflammatory regulation. [ABSTRACT FROM AUTHOR]

With the advancement of living standards in modern society and the emergence of an aging population, an increasing number of people are becoming interested in the topic of aging and anti-aging. An important feature of aging is skin aging, and women are particularly concerned about skin aging. In the field of cosmetics, the market share of anti-aging products is increasing year by year. This article reviews the research and development progress of skin aging and related active compounds both domestically and internationally in recent years. The results show that, in terms of the research on skin aging, the popular theories mainly include free radicals and oxidative stress theory, inflammation theory, photoaging theory, and nonenzymatic glycosyl chemistry theory. In terms of research on the active ingredients with anti-aging activities in the skin, there are numerous reports on related products in clinical studies on human subjects, animal experiments, and experimental studies on cell cultures, with a variety of types. Most of the compounds against skin aging are sourced from natural products and their action mechanisms are mainly related to scavenging oxygen free radicals and enhancing antioxidant defenses. This review provides important references for the future research of skin aging and the development of related products. Although there is a great progress in skin aging including related active ingredients, ideal compounds or products are still lacking and need to be further validated. New mechanisms of skin aging, new active ingredients sourced from natural and artificial products, and new pharmaceutical forms including further clinical validations should be further investigated in the future. [ABSTRACT FROM AUTHOR]

In the mammalian testis, extensive restructuring takes place across the seminiferous epithelium at the Sertoli-Sertoli and Sertoli-germ cell interface during the epithelial cycle of spermatogenesis, which is important to facilitate changes in the cell shape and morphology of developing germ cells. However, precise communications also take place at the cell junctions to coordinate the discrete events pertinent to spermatogenesis, namely spermatogonial renewal via mitosis, cell cycle progression and meiosis, spermiogenesis and spermiation. It is obvious that these cellular events are intimately related to the underlying actin-based cytoskeleton which is being used by different cell junctions for their attachment. However, little is known on the biology and regulation of this cytoskeleton, in particular its possible involvement in endocytic vesicle-mediated trafficking during spermatogenesis, which in turn affects cell adhesive function and communication at the cell-cell interface. Studies in other epithelia in recent years have shed insightful information on the intimate involvement of actin dynamics and protein trafficking in regulating cell adhesion and communications. The goal of this critical review is to provide an updated assessment of the latest findings in the field on how these complex processes are being regulated during spermatogenesis. We also provide a working model based on the latest findings in the field including our laboratory to provide our thoughts on an apparent complicated subject, which also serves as the framework for investigators in the field. It is obvious that this model will be rapidly updated when more data are available in future years. [ABSTRACT FROM AUTHOR]

A laboratory method combining tile high-energy mechanical ball milling and high static pressure has been suggested for modelling synthesis of coesite in the Earth's crust. A window of milling time, a mechanical collision-indeed intermediate phrase of α-quartz and its condition of easily crystallizing into coesite under the condition of 3.0 GPa. 923 K. < 1.0 rain have been discovered. The new method needs much shorter synthesizing lime and lower synthesizing critical pressure than those used before. The Raman spectra for the coesite synthesized by the present method have covered all the information of those natural and synthesized coesites reported before. It is demonstrated that this method has a great potential in geo-science research and implied the other possible mechanism of coesite formation in the Earth's crust. [ABSTRACT FROM AUTHOR]

Pr1−xCaxCrO3 (x=0.0–0.5) samples were prepared by the sol–gel method. The sintering temperature of the samples can decrease to 1573 K. The crystal structures of Pr1−xCaxCrO3 at room temperature all are of the othorhombic perovskite GdFeO3-type. Compared to the commonly used Lanthanum chromite interconnect material, Pr0.6Ca0.4CrO3 is better in the properties of conductivity. XPS analysis indicates that the chromium ions are in a mixed valence state. The introduction of Ca2+ into the lattice is compensated by the oxidation of Cr3+ to Cr6+. With increasing X, the amount of Cr6+ increases. The presence of Cr6+ is one of the key factors that affect the electrical conductivity of Pr1−xCaxCrO3. [Copyright &y& Elsevier]

Bamboo photoaging refers to the chemical and physical changes in the surface after sunlight during outdoor/indoor use, such as texture roughness, polymer molecular chain fracture, and chemical structure changes. The study of bamboo aging during storage is an important part of the industrialization of bamboo as a substitute for plastic initiative. Photoaging during bamboo warehousing and its use is an important factor affecting performance and the use of the final product. To better evaluate the aging response mechanism caused by ambient light during bamboo warehousing, four aging conditions including ultraviolet light aging (UV-aging), indoor-light/light-avoidance cycle (Control), light avoidance (Avoid-light), and 90% RH (Avoid-light 90%) were simulated. The dimensional stability, mass, density, morphology, compressive mechanical strength, and other properties were monitored periodically according to 0, 7, 14, 28, 56, and 180 d. The change mechanism of bamboo under photoaging conditions was analyzed using SEM, FTIR, XRD, and TG. The synergistic effect of different factors under photoaging conditions was studied by redundancy analysis, and different photoaging environment prediction models were established using the long- and short-term memory (LTSM) model. The results showed that during the warehousing cycle of 180 d, the damage of light intensity to bamboo exposure was greater than that of the avoid-light treatment group, the humidity factor was negatively correlated with mechanical properties, the light factor was highly negatively correlated with dimensional stability, and the 30%–60% RH avoid-light condition showed excellent durability. The predictability of photoaging performance evaluation in a warehousing environment has important reference value for industry. • Dimensional and mechanic are affected by light and humidity aging. • Avoid-light as potential storage method to enhance carbon sink strategy. • Predictability of bamboo quality during storage can be perceived by LSTM. • Accurate forecasting was conducted based on process simulation. • Avoid-light conditions promise sustainable and cleaner recycling. [ABSTRACT FROM AUTHOR]

Electron-doped perovskite manganite Ca0.9R0.1MnO3 (R=La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Yb) polycrystalline samples were prepared and their transport and thermoelectric properties were studied from room temperature to 1000 K. The transport behavior for all the samples is adiabatic small polaron hopping mechanism below 600 K but changes to metallic conductivity at higher temperature. Above 600 K, more 3d electrons of Mn3+ ions will occupy eg orbitals, resulting in the variation in thermoelectric power values. For all the samples, thermoelectric power is only determined by carrier concentration, but resistivity also rests with effective bandwidth. The size matching between Ca2+ and R3+ ions together with heavier R3+ doping can improve thermoelectric performance evidently. Combining these two factors, Ca0.9Dy0.1MnO3 and Ca0.9Yb0.1MnO3 reach ZT=0.2 at 1000 K, suggesting that they can be efficient high temperature n-type thermoelectric oxide materials. [ABSTRACT FROM AUTHOR]

Backgrounds: The Sertoli cell that plays a vital role during spermatogenesis is a known target of physiological and pathological factors affecting testicular development. Tumor necrosis factor alpha (TNFα) participates in the blood–testis barrier reconstruction, cell apoptosis, and inflammatory response by recognizing receptors on Sertoli cell. TNFα has also been shown to induce the proliferation of immature Sertoli cell in vitro, yet the mechanism still remains unclarified. Objectives: This study was designed to investigate the effect of TNFα on blood–testis barrier development during puberty and the underlying mechanisms of TNFα‐induced immature Sertoli cell proliferation. Materials and methods: Immature male Sprague–Dawley rats of postnatal day 12 were intraperitoneally injected with TNFα. Biotin‐labeled method was used to detect permeability of the developing blood–testis barrier after TNFα treatment, and the distribution of occludin and junctional adhesion molecule‐A (JAM‐A) were detected by immunofluorescence. Sertoli cells isolated from Sprague–Dawley rats of postnatal day 10 were cultured in vitro and treated with TNFα. Cell proliferation rate was reflected by Cell Counting Kit‐8 (CCK‐8) and 5‐ethynyl‐2'‐deoxyuridine (EdU) assay. Immunoblot and quantitative polymerase chain reaction were used to detect the expression of proliferating cell nuclear antigen, Fbxo4, and cyclin D1. Immunoprecipitation was used to detect the ubiquitination of cyclin D1 and the interaction between Fbxo4 and cyclin D1. Ammonium pyrrolidinedithiocarbamate (PDTC) was applied to detect the effect of nuclear factor kappaB (NFκB) activity inhibition on TNFα‐induced Sertoli cell proliferation. The adenoviral recombinant plasmid containing rat Fbxo4 gene was constructed to investigate the effect of Fbxo4 overexpression on Sertoli cell proliferation promoted by TNFα. Results: The in vivo experiment revealed a significant delay of blood–testis barrier maturation in pubertal rats caused by exogenous TNFα. TNFα (10 ng/ml) treatment in vitro was found to promote the proliferation of immature Sertoli cells, accompanied with increased NFκB activity and cyclin D1 protein level. The level of Fbxo4 and ubiquitination of cyclin D1 were decreased after TNFα treatment. Inhibitor of NFκB or overexpression of Fbxo4 could both reverse the TNFα‐induced proliferation of immature Sertoli cells, meanwhile restore the ubiquitin–proteasome system‐dependent degradation of cyclin D1. Overexpression of Fbxo4 could not affect the activation of NFκB caused by TNFα. Conclusion: These results indicate that TNFα inhibits the ubiquitination and degradation of cyclin D1 through the NFκB pathway, thereby promoting the proliferation of immature Sertoli cell in vitro and inducing the delay of blood–testis barrier maturation in pubertal rats. [ABSTRACT FROM AUTHOR]

Backgrounds: In the testis, spermatocytes and spermatids rely on lactate produced by Sertoli cells (SCs) as energy source. Transforming growth factor‐beta 3 (TGF‐β3) is one of the generally accepted paracrine regulatory factors of SC‐created blood–testis barrier (BTB), yet its role in SC glycolysis and lactate production still remains unclear. Objectives: To investigate the effect of TGF‐β3 on glycolysis and lactate production in SCs and determine the role of lethal giant larvae 2 (Lgl2) and Notch signaling activity during this process. Materials and methods: Primary cultured rat SCs and TM4 cells were treated with different concentrations of TGF‐β3. In some experiments, cells were transfected with siRNA specifically targeting Lgl2 and then treated with TGF‐β3 or N‐[N‐(3,5‐difluorophenacetyl)‐l‐alanyl]‐S‐phenylglycine t‐butyl ester. Lactate concentration, glucose and glutamine (Gln) consumption in the culture medium, activity of phosphofructokinase (PFK), lactate dehydrogenase (LDH), and glutaminase (Gls), ATP level, oxygen consumption, extracellular acidification, and mitochondrial respiration complex activity were detected using commercial kits. The protein level of Lgl2, LDH, monocarboxylate transporter 4 (MCT4), and activity of Akt, ERK, p38 MAPK, and Notch pathway were detected by Western blot. The stage‐specific expression of Jagged1 was examined by immunohistochemistry (IHC) and qPCR after laser capture microdissection. Spermatogenesis in rat testis injected with recombinant Jagged1 (re‐Jagged1) was observed by HE staining, and lactate concentration in testis lysate was measured at a different day point after re‐Jagged1 treatment. Results: Significant enhancement of lactate concentration was detected in a culture medium of both primary SCs and TM4 cells treated with TGF‐β3 at 3 or 5 ng/ml. Besides, other parameters of glycolysis, that is, glucose and Gln consumption, enzyme activity of PFK, LDH, and Gls displayed different levels of increment in primary SCs and TM4 cells after TGF‐β3 treatment. Mitochondria respiration of SCs was shown to decrease in response to TGF‐β3. Lgl2, MCT4, activity of ERK, and p38 MAPK were up‐regulated, whereas Akt and Notch pathway activity were inhibited by TGF‐β3. Silencing of Lgl2 in SCs affected lactate production and attenuated the previous effects of TGF‐β3 on SC glycolysis except for Gln consumption, Gls activity, and activity of Akt, ERK, and p38. N‐[N‐(3,5‐difluorophenacetyl)‐l‐alanyl]‐S‐phenylglycine t‐butyl ester (DAPT) treatment in SCs antagonized glycolysis suppression caused by Lgl2‐silencing. In vivo analysis revealed a stage‐specific expression of Jagged1 in contrary with TGF‐β3. Activating Notch signaling by re‐Jagged1 resulted in restorable hypospermatogenesis and lowered lactate level in rat testis. Conclusion: TGF‐β3 induces lactate production in SC through up‐regulating Lgl2, which weakened the Notch signaling activity and intensified glycolysis in SCs. Thus, besides the known function of TGF‐β3 as the BTB regulator, TGF‐β3‐Lgl2‐Notch may be considered an important pathway controlling SC glycolysis and spermatogenesis. [ABSTRACT FROM AUTHOR]

[Display omitted] • The N,S-containing hyper-cross-linked polymers were prepared by a simple one-step Friedel-Crafts reaction. • HCP-N/S-2 possessed the highest TC and DCF adsorption capacity around 138.1 and 140.5 mg/g due to the existence of N and S. • The TC and DCF adsorption mechanism of HCP-N/S-2 is primarily derived from pore-filling, π-π stacking, H-bonding, and electrostatic interaction. Novel N,S-containing hyper-cross-linked polymers were designed for the adsorption of tetracycline (TC) and diclofenac (DCF) in water. The surface area, pore volume, and average pore diameter of N,S-containing hyper-cross-linked polymers were 32.5 m2/g, 0.11 cm3/g, and 16.8 nm, respectively. The pseudo-second-order and Langmuir isotherm models indicated that TC and DCF adsorption was chemisorption-dominated and exhibited a monolayer homogeneous adsorption. This adsorbent exhibited the highest TC and DCF adsorption capacity around 138.1 and 140.5 mg/g. Moreover, the adsorption capacity still maintained 85 % of the initial adsorption capacity after 10 adsorption–desorption cycles. Continuous fixed-bed runs demonstrated that this adsorbent reduced the TC and DCF concentrations to 1 mg/L at 738 and 612 BVs, respectively. The TC and DCF adsorption mechanism was primarily derived from pore-filling, π-π interaction, H-bonding, and electrostatic interaction. Therefore, N,S-containing hyper-cross-linked polymers proves to be an efficient adsorbent of TC and DCF during wastewater treatment. [ABSTRACT FROM AUTHOR]

Backgrounds: Sterility induced by anti‐cancer treatments has caused significant concern, yet the mechanism and treatment exploration are little for male infertility after cancer therapy. Busulfan, the antineoplastic that was widely applied before bone marrow transplantation, was known to induce male reproductive disorder. Objectives: To investigate the effect of busulfan on blood–testis barrier function in adult rats and determine whether noncollagenous 1 domain peptide, the biologically active fragment proteolyzed from the collagen α3 chain (IV) by matrix metalloproteinase 9, was involved during this process. Materials and methods: Adult male rats were treated with one‐dose or double‐dose of busulfan (10 mg/kg) before euthanized at day 35. Blood–testis barrier integrity assay, HE staining, immunofluorescence, and Western blot were used to validate the effect of busulfan on blood–testis barrier permeability and spermatogenesis. JNJ0966 was applied to specifically inhibit the matrix metalloproteinase 9 activity. The polymerization activity of F‐actin/G‐actin and microtubule/tubulin in the testis were assessed by using commercial kits. Results: A noteworthy blood–testis barrier injury and significant up‐regulation of matrix metalloproteinase 9 activity and noncollagenous 1 level after a single‐dose busulfan (10 mg/kg) treatment in adult rat testis were revealed. The application of JNJ0966 was found to decrease noncollagenous 1 level and rescue the busulfan‐induced blood–testis barrier injury including the mis‐localization of junction proteins across the seminiferous epithelium, by recovering the organization and polymerization of both F‐actin and microtubule. The busulfan‐induced spermatogenesis impairment was also improved by JNJ0966. Conclusion: These findings thus demonstrate that the elevation in matrix metalloproteinase 9 and noncollagenous 1 might participate in busulfan‐induced blood–testis barrier disruption in adult male rats. As such, busulfan‐induced male infertility could possibly be managed through interventions on noncollagenous 1 production. [ABSTRACT FROM AUTHOR]

In the past few years, there has been an increasing worry about the pollution of water caused by the presence of heavy metals. To address this environmental issue, a highly effective adsorbent called ZIF-67/CS-SH was developed. This adsorbent was prepared by grafting thioglycolic acid and loading a metal-organic framework called ZIF-67 onto chitosan, to remove Hg(II) from water. Confirmation of the ZIF-67/CS-SH was achieved by employing a range of techniques including FTIR, XRD, TGA, SEM, EDS, BET, and XPS. Due to the presence of abundant active sites (-SH, O/N-containing functional groups) and ZIF-67, ZIF-67/CS-SH exhibited a high adsorption capacity (949 mg/g at 298 K) and rapid adsorption kinetics (20 min for 91 % removal). The optimal pH for the adsorption process was found to be 5. The adsorption process followed a pseudo-second-order kinetics and Langmuir isotherm, with chemisorption being the main adsorption mechanism. The adsorption process was determined to be spontaneous and endothermic. Additionally, ZIF-67/CS-SH demonstrated selective adsorption in the presence of other metal cations at concentrations of 100 mg/L. Furthermore, ZIF-67/CS-SH exhibited excellent regenerative properties, with only a 10 % decrease in adsorption capacity after ten cycles. The key adsorption sites were identified as the –SH groups, O/N-containing functional groups, and ZIF-67 in ZIF-67/CS-SH through FTIR, EDS, and XPS analyses. Considering its outstanding performance in removing Hg(II), ZIF-67/CS-SH shows promise for application in industrial wastewater treatment. The schematic diagram of adsorption mechanism. [Display omitted] • This adsorbent was prepared by thioglycolic acid and metal-organic framework. • ZIF-67/CS-SH exhibited a high adsorption capacity (965 mg/g at 308 K). • The key adsorption sites were –SH groups and O/N-containing functional groups. [ABSTRACT FROM AUTHOR]

• A novel MOF-5/PNaSS/SA hydrogel was prepared. • The Pb(II) and TC adsorption capacities of MOF-5/PNaSS/SA are 189 and 181 mg/g. • Pore filling, electrostatic, ππ stacking, and hydrogen bond are adsorption mechanism. Novel alginate-based nanocomposite hydrogels with MOF-5 were prepared to remove Pb(II) and TC from water. The structure was characterized and analyzed by FTIR, XRD, TGA, SEM-EDS, BET, zeta, and XPS. Key factors, such as pH, adsorbent dosage, temperature, and coexisting salt ions were investigated in batch adsorption. The optimized MOF-5/PNaSS/SA demonstrated superior adsorption ability compared to SA and PNaSS/SA. In experimental tests, it exhibited maximum adsorption capacities for Pb(II) (189 mg/g) and TC (181 mg/g) at pH 6. The second-order kinetics model and the Langmuir isotherm model accurately described the sorption data of MOF-5/PNaSS/SA. Thermodynamic analysis indicated that the adsorption of MOF-5/PNaSS/SA was an exothermic and spontaneous process. MOF-5/PNaSS/SA also displayed excellent selectivity in adsorption and resistance to interference from salt ions. Moreover, the adsorption-desorption experiments demonstrated the recyclability of MOF-5/PNaSS/SA, as its adsorption capacity remained high level after ten cycles. The presence of O/S-containing groups and benzene rings played a crucial role in the adsorption mechanism, as confirmed by FTIR and XPS. In conclusion, MOF-5/PNaSS/SA has a high adsorption capacity and can effectively remove Pb(II) and TC from wastewater. [ABSTRACT FROM AUTHOR]

Abstract: The cathode material La1−x Sr x CuO3−δ (x =0.15, 0.2, 0.3, 0.4) was synthesized by a sol–gel method. X-ray diffraction revealed it to form a single phase of perovskite. The investigation of the electrical properties suggested that La0.7Sr0.3CuO3−δ has the highest electrical conductivity. La0.7Sr0.3CuO3−δ has better electrochemical properties than La0.6Sr0.4CoO3−δ . When using La0.7Sr0.3CuO3−δ as cathode based on SDC electrolyte one can obtain higher current density and power density at intermediate temperatures. [Copyright &y& Elsevier]

The equilibrium geometries and the vibrational frequencies of M2Te (M=Cu,Ag,Au) systems were calculated at HF, second- to fourth-order Møller–Plesset perturbation theory (MP2, MP3, MP4), and coupled cluster methods (CCSD, CCSD(T)) levels, and using relativistic and non-relativistic pseudopotentials for Au2Te. The calculated geometries indicated that the species has a bent structure of about 70° angle. Electron correlation corrections on the bond angle are very significant, in general, angles M–Te–M are reduced from 90° to 70°, and on the bond length are small. The property of the electron correlation is analyzed, it seems to be explained in terms of a tangential force. Relativistic effects significantly shorten the bond length of Au2Te. Comparing Au2Te with Cu2Te and Ag2Te, it could be predicted that the Au2Te is relatively stable. [Copyright &y& Elsevier]

A series of Fe, Mn, and Cu doped Ca3Co4O9+δ samples, Ca3(Co,M)4O9+δ (M=Fe, Mn, and Cu), were fabricated by cold high-pressure compacting technique. Their thermoelectric properties were investigated from room temperature up to 1000 K. The cold high-pressure compacting method is advantageous to increasing density and texture, in favor of the improvement of thermoelectric performance. The electrical transport measurements indicate that Fe/Mn substitutes for Co mainly in [CoO2] layers whereas the substitution of Cu for Co takes place in [Ca2CoO3] layers. The thermoelectric properties as well as electronic correlations depend not only on the substitution ion but also the Co site that is replaced. Thermopower can be well calculated by the carrier effective mass according to Boltzmann transport model, indicating that the electronic correlation plays a crucial role in the unusual thermoelectric characteristics of this system. From the changes in thermopower, resistivity, and thermal conductivity, thermoelectric performance of Ca3Co4O9+δ is efficiently improved by these transition metals doping. Fe doped samples possess the highest ZT values. Combining cold high-pressure technique, ZT of Ca3Co3.9Fe0.1O9+δ can reach ∼0.4 at 1000 K, which is quite large among ceramic oxides, suggesting that Fe doped Ca3Co4O9+δ could be a promising candidate for thermoelectric applications at elevated temperatures. [ABSTRACT FROM AUTHOR]

The effects of interfacial states on the temperature dependence of the magnetoresistance (MR) of Sr2FeMoO6-glass composites have been studied. X-ray diffraction analyses show that the glass is most likely located at the grain boundary without causing a change of the crystal structure of Sr2FeMoO6. The variation of the resistance with temperature and magnetic field indicates that the added glass layer has profound influence on the MR properties. At low temperature, the MR in low fields is enhanced notably because the insulating barrier for the intergranular tunneling is improved by adding the glass layer at the grain surface. However, at high temperature, the MR decreases rapidly with the increase of temperature due to, in addition to the enhancement of spin-independent hopping of electrons through the localized states, the fast decay of spin polarization at the surfaces of the grains. This decay is induced by the separation of the ferromagnetic grains with the nonmagnetic glass layer at the grain boundaries. [ABSTRACT FROM AUTHOR]

In this paper, we report the magnetoresistance and the Hall effect in the Fe3O4–SiO2–Si structure. Single phase magnetite films were deposited on n-type silicon substrates using laser molecular beam epitaxy. When the temperature is increased beyond 230 K, the resistance drops rapidly because the conduction path starts to switch from the Fe3O4 film to the inversion layer underneath the native SiO2 via thermally assisted tunneling. A large negative magnetoresistance is observed at about 230 K, and this maximum shifts to higher temperature with increasing film thickness. Hall effect data of the structure show that the carriers are holes above the channel switching temperature. Our results confirm that the large magnetoresistance at ∼230 K originates from the amplification of the magnetoresistance of the magnetite in the Fe3O4–SiO2–Si structure. [ABSTRACT FROM AUTHOR]

Structural, magnetic, and electrical properties of Bi1-xPbxFeO3 (x=0, 0.1, 0.2, and 0.3) polycrystalline prepared by solid solution route were studied. The crystal structure data obtained from x-ray diffraction indicate that the solid solution Bi1-xPbxFeO3 successively transforms from rhombohedral to pseudocubic symmetry with an increase in the Pb concentration. The observed weak ferromagnetism and ferroelectricity at room temperature indicated the multiferroic nature of Pb-doped BiFeO3 compounds. The magnetoelectric coupling was estimated by the changes in the dielectric constant with an external magnetic field. It was found that the value of magnetodielectric effect have a maximum of 0.4% for Bi0.7Pb0.3FeO3 ceramic under a magnetic field of 12 kOe at room temperature. [ABSTRACT FROM AUTHOR]

In this paper, we investigate the influence of high temperature and high pressure (hot pressure) on the magnetic and transport properties of polycrystalline CrO2 samples compacted under high pressure and high temperature of up to 5 GPa and 600 °C, respectively. The magnetic moment increases with compacting temperature, and a metal-semiconductor transition is observed in hot-pressed samples, different from the cold-pressed samples. These results indicate that the formation of Cr2O3 at the grain boundaries of CrO2 is suppressed by hot pressure. The magnitude of low field magnetoresistance of up to 1 T at 5 K is enhanced first with the increase of compacting temperature and then decreased under higher compacting temperature. This result can be well explained by the change of spin-dependent tunneling at the modulated grain boundaries of CrO2 due to the transformation from Cr2O3 to CrO2 under hot pressure. [ABSTRACT FROM AUTHOR]

Background/Aims: Transforming growth factor-β3 (TGF-β3) has been proved to perturb the blood-testis barrier (BTB) by accelerating junction protein endocytosis in Sertoli cells (SCs) to accommodate the traversing of preleptotene spermatocytes across the BTB around stage VIII in rat. Yet the molecular network underlying the impairment of TGF-β3 on BTB integrity is not fully elucidated. Our study herein was designed to investigate the participation of microRNA-142-3p (miR-142-3p), which has been reported to affect TGF-β3 signaling via different pathways, during BTB dynamics and the corresponding mechanisms. Methods: MiRNA mimic or agomiRNA was co-administered with or without TGF-β3 in the cultured SCs or in the rat testis. The SC permeability barrier function was reflected by measuring the transepithelial resistance (TER) and the permeability of the sodium fluorescein (Na-F). The BTB integrity was detected by the permeation of biotin. A luciferase reporter assay was used to testify the potential target of miR-142-3p, lethal giant larvae 2 (Lgl2). Laser capture microdissection (LCM) was applied to acquire cell components of different stages of seminiferious tubules, followed by detection of the expression levels of miR-142-3p, TGF-β3, and Lgl2 by qPCR. The SC barrier function was also detected as above in the presence of TGF-β3 after Lgl2 knockdown. Results: We revealed a reversion of TGF-β3-induced BTB impairment after miR-142-3p treatment both in vitro and in vivo. Meanwhile, the activation of Cdc42 and reduction in occludin aroused by TGF-β3 were also reversed by miR-142-3p. The predicted binding of miR-142-3p with 3’-untranslated region (3’-UTR) of Lgl2, was verified by the luciferase assay. Moreover, an increased Lgl2 level in TGF-β3-treated SCs was found and correlated stage-specific expressions of TGF-β3, miR-142-3p, and Lgl2 were revealed. Knockdown of Lgl2 in SCs was shown to partially antagonize the BTB disruption mediated by TGF-β3. Conclusions: Collectively, our results suggest a resistance of miR-142-3p on the BTB impairment caused by TGF-β3 during the seminiferous epithelial cycle by targeting Lgl2. [ABSTRACT FROM AUTHOR]

The electrolyte material Ce 0.85 Sm 0.15 O 1.92 (SDC) powders are synthesized by glycine–nitrate processes and BaCe 0.83 Y 0.17 O 3− δ (BCY) powders are synthesized by sol–gel processes, respectively. Then SDC–BCY composite electrolytes are prepared by mixing SDC and BCY. The SDC and BCY powders are mixed in the weight ratio of 95:5, 90:10 and 85:15 and named as SB95, SB90 and SB85, respectively. The electrical properties of SDC and SDC–BCY composites are investigated. The experimental results show that SDC–BCY composites exhibit the excellent conductivity and could significantly enhance the fuel cell performances. The behavior that SDC–BCY composites display hybrid proton and oxygen ion conduction is substantiated. Among these electrolytes, the maximum power density reaches as high as 159 mW cm −2 for the fuel cell based on SB90 composite electrolyte at 600 °C. [ABSTRACT FROM AUTHOR]

Highlights: [•] Functionally graded cathodes based on GdBaCo2O5+δ oxide were prepared. [•] The cathode consists of an electrochemical active layer and a high conductive layer. [•] The cathode shows improved electrochemical performance and high thermal stability. [Copyright &y& Elsevier]

A novel method for fabricating Ni(NO3)2 solution impregnated YSZ (YSZ: Yttria Stabilized Zirconia) anodes for solid oxide fuel cells (SOFCs) is presented. In order to reduce the impregnation cycles and increase the reliability of the YSZ membrane, a YSZ support with a porosity of ∼60% is soaked in a saturated Ni(NO3)2 solution with an increased temperature of 80 °C. The impregnated anode is dried in a vacuum drying device without heating, resulting in a flower-like Ni(NO3)2·6H2O crystal. The formed porous structure is likely to facilitate the impregnating process and considered to be the key to success of the impregnation process with saturated solution. After heating at 700 °C, a novel needle-shaped NiO is presented, which exhibits some advantages including fast preparation, high connectivity, large specific surface area and high operational stability (i.e. high aggregation resistance). For the purpose of comparison, Ni(NO3)2 solution impregnated YSZ anodes prepared through the conventional impregnation process are also characterized under the same conditions. [ABSTRACT FROM AUTHOR]

Abstract: In this study, we will report our investigation for La0.75Sr0.25Cr0.5Mn0.5O3−δ (LSCrM) based anodes impregnated with solutions of cobalt (Co) nitrate. A YSZ supported SOFC with pure LSCrM anode and La0.7Sr0.3MnO3 (LSM) cathode exhibits the maximum power density (P max) of 58.7 and 5.2 mW cm−2 at 850 °C in dry H2 and dry CH4. After the modification of anode with Co nitrate, the P max reaches 196.2 mW cm−2 in dry H2 and 28.5 mW cm−2 in dry CH4, about 3.34 times and 5.48 times increase, respectively. These results indicate that Co is also a potential catalyst for LSCrM anode. Moreover, the effect of impregnation amount of catalyst on the cell performance is also evaluated in this study. [Copyright &y& Elsevier]

Abstract: The electrolyte materials Ce0.9Gd0.1O1.9 (GDC) and La0.9Sr0.1Ga0.8Mg0.2O2.85 (LSGM) were synthesized by means of glycine-nitrate processes, respectively, then GDC-LSGM composite electrolytes were prepared by mixing GDC and LSGM. The GDC and LSGM powders were mixed in the weight ratio of 95:5, 90:10 and 85:15 and named as GL9505, GL9010 and GL8515. Their structures and ionic conductivities were investigated by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), Raman and AC impedance spectroscopy. The grain sizes of GDC-LSGM composites could be increased distinctly and the grain boundary resistance could be significantly decreased by small addition of LSGM. The experimental results show that the GDC-LSGM composites exhibit excellent ionic conductivity and could significantly enhance the fuel cell performances. The open circuit voltages are higher in the cell with composite electrolytes than in the cell with single GDC as electrolyte at the working temperature. Among these electrolytes, GL9505 has the highest ionic conductivity and the maximum power density. [Copyright &y& Elsevier]

Abstract: Uniform, dense and continuous coatings of La0.8Sr0.2MnO3−δ (LSM) have been successfully deposited on dense/porous La0.6Sr0.4Co0.2Fe0.8O3−δ (LSCF) substrates via a one-step drop-coating process using a water-based solution in order to improve the operating stability of solid oxide fuel cell cathode. The processing conditions were optimized by precise control of the composition of infiltrating solution, including chelating agents (glycine, citric acid and ethylene glycol), surfactants (polyvinyl alcohol (PVA), polyethylene glycol (PEG) and polyvinyl pyrrolidone (PVP)) and pH values (5.25, 4.29, 3.01 and 2.09). Ethanol was found to improve the wetting ability of the water-based solution significantly, but unfortunately causing precipitation. The symmetrical and full cells tests demonstrated that both performance and stability of LSCF cathode can be enhanced by surface modification with an optimized LSM film coating, leading to ∼31% reduction in cathodic polarization resistance and ∼45% improvement in power density (without observable degradation) for almost 350 h operation at 750 °C under a constant voltage of 0.7 V. [Copyright &y& Elsevier]

Abstract: We reported nano-structured Ag modified Ba0.5Sr0.5Co0.6Fe0.4O3−δ (Ag@BSCF) cathode for solid oxide fuel cells (SOFCs) that is prepared by vacuum assisted electroless deposition technique. We show that the concentration of Ag can be easily adjusted by tuning the deposition time without altering the perovskite structure of the pristine BSCF. The effect of Ag loading on the electrochemical performance of the material has been systematically studied by varying the Ag loading and the working condition (oxygen partial pressure). An optimized electrode performance is observed with an Ag loading of ∼2 wt%. We demonstrate that the presence of Ag significantly reduces the electrode ohmic resistance and enhances the catalytic O2 reduction performance of the BSCF cathode. [Copyright &y& Elsevier]

The effect of gas supply method on the performance of a single-chamber solid oxide fuel cell micro-stack and single cells was studied, and a novel gas supply method with separated gas vents in the gas tube was proposed. The traditional gas supply method was also investigated for comparison. Results showed that the single cells could obtain a uniform open-circuit voltage and power output by using the separated gas supply method. For the traditional gas supply method, the cell at the outlet position yielded inferior performance compared to that of the inlet cell. The gas flow rate showed a significant effect on the performance of the cells. Finally, the stack operated with the separated gas supply method produced a higher power output than that operated with the traditional gas supply method. [ABSTRACT FROM AUTHOR]

How prebiotic metabolic pathways could have formed is an essential question for the origins of life on early Earth. From the abiogenetic point of view, the emergence of primordial metabolism may be postulated as a continuum from Earth's geochemical processes to chemoautotrophic biochemical procedures on mineral surfaces. In the present study, we examined in detail the reversible amination of α-ketoglutarate on UV-irradiated ZnS particles under variable reaction conditions such as pH, temperature, hole scavenger species and concentrations, and different amino acids. It was observed that the reductive amination of α-ketoglutarate and the oxidative amination of glutamate were both effectively performed on ZnS surfaces in the presence and absence of a hole scavenger, respectively. Accordingly, a photocatalytic mechanism was proposed. The reversible photochemical reaction was more efficient under basic conditions but independent of temperature in the range of 30–60 °C. SO32− was more effective than S2− as the hole scavenger. Finally, we extended the glutamate dehydrogenase-like chemistry to a set of other α-amino acids and their corresponding α-oxo acids and found that hydrophobic amino acid side chains were more conducive to the reversible redox reactions. Since the experimental conditions are believed to have been prevalent in shallow water hydrothermal vent systems of early Earth, the results of this work not only suggest that the ZnS-assisted photochemical reaction can regulate the redox equilibrium between α-amino acids and α-oxo acids, but also provide a model of how prebiotic metabolic homoeostasis could have been developed and regulated. These findings can advance our understanding of the establishment of archaic non-enzymatic metabolic systems and the origins of autotrophy. [ABSTRACT FROM PUBLISHER]

Abstract: The perovskite-type La0.9Sr0.1Ga0.8Mg0.2O3-δ(LSGM9182) with high oxygen-ionic conductivity is successfully synthesized using conventional solid-state reaction. The phase composition, grain size distribution, relative density, and oxygen-ionic conductivity of the samples are studied. The XRD result shows that the main perovskite LaGaO3 phase can be produced at 1,250 °C, with trace amount of second phase LaSrGaO4. When the temperature increases to 1,400 °C, the pure phase LSGM can be obtained. The relative density of LSGM pellets sintered at 1,400 °C reaches 98.08%. The average grain size of final powders is ∼0.12 μm, which is appropriate for the deposition of LSGM electrolyte film. The ideal oxygen-ionic conductivities of 0.04, 0.06, and 0.08 S cm−1 can be obtained at 700 °C, 750 °C, and 800 °C, respectively. Porous anode supported single cells with LSGM electrolyte film are fabricated using the as-prepared LSGM powders and the cells provide an open-circuit voltage of above 1.0 V, revealing that the LSGM film is gas-tight and crack-free. [Copyright &y& Elsevier]

Abstract: The electrolyte materials Ce0.85Sm0.15O1.9 (SDC) and La0.9Sr0.1Ga0.8Mg0.2O2.85 (LSGM) are synthesized by glycine–nitrate processes, respectively. Then SDC–LSGM composite electrolytes are prepared by mixing SDC and LSGM. The SDC and LSGM powders are mixed in the weight ratio of 95:5, 90:10 and 85:15 and named as SL9505, SL9010 and SL8515. SEM shows the grain size of SDC–LSGM composites increased distinctly. The electrical properties of SDC and SDC–LSGM composites are investigated. The grain boundary resistance could be significantly decreased by small addition of LSGM. The experimental results show that the SDC–LSGM composites exhibit excellent conductivity and could significantly enhance the fuel cell performances. Among these electrolytes, SL9505 has the highest conductivity and the maximum power density. [Copyright &y& Elsevier]

The molecular structural and Raman spectroscopic characteristics of β-carotene and lycopene are investigated by density functional calculations. The effects of molecular structure and solvent environment on the Raman spectra are analyzed by comparing the calculated and measured results. It is found that the B3LYP/6-31G(d) method can predict the reasonable result for β-carotene, but the ν1 Raman activities of lycopene overflow at all the used theoretical methods because of the longer conjugation length. The calculated results indicate that the rotation of β-rings in β-carotene impedes the delocalization of π-electrons, shortens the effective conjugation length, and results in higher frequency and lower activity of the ν1 mode in β-carotene than lycopene. The measured ν1 bands of β-carotene and lycopene shift respectively to higher and lower frequencies in solution compared with that in crystals since the crystal packing forces can lead to different conformational variations in the carotenoids molecules. The polarized continuum model theoretical analysis suggests that solvent has slight (significant) effects on the Raman frequencies (intensities) of both carotenoids. [ABSTRACT FROM AUTHOR]

Abstract: The performance of an anode-supported solid oxide fuel cell with nanosized Ce0.8Sm0.2O1.9 (SDC) impregnated GdBaCo2O5+δ (GBCO) cathode is evaluated under various operation conditions. An SDC interlayer is applied between 8 mol% yttria-stabilized zirconia (8YSZ) electrolyte and cathode to prevent undesired chemical reaction. At 700 °C, the fuel cell yields a maximum power density of 790 mW cm−2 when using simulated air as oxidant, which is promoted to 1100 mW cm−2 in oxygen flow. The activation energies of ohmic resistance are smaller than that of bulk YSZ due to non-YSZ contribution. Electrode polarization resistance changes with fuel cell voltage while ohmic resistance nearly remains constant. The fuel cell output is mainly determined by the electrode polarization. [Copyright &y& Elsevier]

Abstract: The oxygen adsorption on Ag/LSM(001) catalysts surfaces has been investigated using first-principles density functional theory calculations. The most favorable oxygen adsorption sites are found to be atop surface Mn atoms on the MnO2-terminated surface and on the hollow positions of the La(Sr)O-terminated LSM(001) surface. The calculated adsorption energies for Ag atom demonstrate that the Ag adsorption at O site is much more favorable than Mn site. The atomic relaxation results indicate that Ag doping produces a strong local perturbation and a large effect on the surface properties. No significant improvement for oxygen adsorption is found due to Ag doping. However, the O2 adsorption energy increases from 0.495eV to 0.937eV due to the pre-adsorbed Ag. It is pre-adsorbed Ag that facilitates O2 adsorption on surface. The bond length and bond population of O2 molecule indicate that Ag atom facilitates O2 molecule dissociative adsorption. The adsorbed Ag on LSM strengthens its activity as SOFCs cathode by acting as an active center at the surface. [Copyright &y& Elsevier]

Abstract: A perovskite-type (Ba0.5Sr0.5)0.85Gd0.15Co0.8Fe0.2O3−δ (BSGCF) oxide has been investigated as the cathode of intermediate temperature solid oxide fuel cells (IT-SOFCs). Coulometric titration, thermogravimetry analysis, thermal expansion and four-probe DC resistance measurements indicate that the introduction of Gd3+ ions into the A-site of Ba0.5Sr0.5Co0.8Fe0.2O3−δ (BSCF) leads to the increase in both oxygen nonstoichiometry at room temperature and electrical conductivity. For example, the conductivity of BSGCF is 148Scm−1 at 507°C, over 4 times as large as that of BSCF. Furthermore, the electrochemical activity toward the oxygen reduction reaction is also enhanced by the Gd doping. Impedance spectra conducted on symmetrical half cells show that the interfacial polarization resistance of the BSGCF cathode is 0.171Ωcm2 at 600°C, smaller than 0.297Ωcm2 of the BSCF cathode. A Ni/Sm0.2Ce0.8O1.9 anode-supported single cell based on the BSGCF cathode exhibits a peak power density of 551mWcm−2 at 600°C. [Copyright &y& Elsevier]

Abstract: In order to optimize the morphology of starting powder, raw GBCO powder synthesized via solid state reaction was repeatedly compacted by uniaxial die pressing at two apparent compaction pressures of 500 and 1000MPa. The particle size distribution curves and SEM images indicated that, with increasing compaction pressure and number of compaction times, the larger particles in the powder were gradually broken apart and the particle size became small and uniform. Then the effect of pressing treatment for the starting GBCO particles on the microstructure and performance of sintered cathode was studied. The results demonstrated that, after being sintered under the same conditions, the cathode prepared from the treated GBCO particles showed a finer microstructure compared with that prepared from the raw GBCO particles. In addition, optimizing the morphology of the starting GBCO powder by pressing treatment could improved the cathode performance and made the polarization resistance of final cathode reduce from 1.33Ωcm2 to 0.40Ωcm2 at 600°C. [Copyright &y& Elsevier]

Abstract: Pyrite is a common mineral at many mining sites. In this study, the mineral pyrite was studied as a Fenton-like reagent for environmental concerns. We selected lactate as a model target molecule to evaluate the Fenton-like catalytic efficiency of pyrite upon organic oxidation. A complete set of control experiments in both aerobic and anaerobic atmospheres unequivocally established that the pyrite in aqueous solution could spontaneously in situ generate OH and H2O2, serving as a Fenton-like reagent to catalyze the oxidation of lactate to pyruvate with no need for additional H2O2. We called it the pyrite-only Fenton-like (PF) reagent. Monitoring concentration changes of lactate and pyruvate with the time indicated that the pyrite mediated the favorable pyruvate formation at pH 4.5, 60°C, under air atmosphere. The PF reaction could be stimulated by visible light illumination. Under the optimum conditions, up to 50% of lactate was degraded within 10d. The results suggest that pyrite and its Fenton-like processes may be potentially practical in wastewater treatment. [Copyright &y& Elsevier]

Abstract: In order to develop cathode materials for intermediate temperature solid oxide fuel cell (IT-SOFC), (Ba0.5Sr0.5)1− x Gd x Co0.8Fe0.2O3− δ (BSGCF: x =0, 0.02, 0.05, 0.08, and 0.1) oxides were synthesized by sol–gel method. The effects of Gd-doping on the phase structure, thermal expansion coefficient (TEC), thermogravimetric (TG) and the electrical conductivity were investigated. All samples have cubic structure and the lattice shrinks with the increasing content of Gd3+. The TEC values of BSGCF are in the range of 20.7–22.4×10−6 K−1 from 50 to 900°C and the abnormal expansion phenomenon at the temperature range of 300–550°C is observed in all these samples, which is related with the loss of lattice oxygen as proved by the TG result. The conductivity of BSGCF10 is three times as large as BSCF at 500°C. While abnormal phenomenon of BSGCF for the x=0.05 is explained through the critical radius calculation. [Copyright &y& Elsevier]

Abstract: In the present paper, the catalytic role of Ag in the oxygen adsorption of LaMnO3(001) surface has been theoretically investigated using first-principles calculations based on the density functional theory (DFT) and pseudopotential method. The O2 adsorption energy is larger for the vertical adsorption and the covalent bond was formed between O2 molecule and surface Mn. The calculation of electronic properties of interaction between Ag atom and LaMnO3(001) surface demonstrates that the most stable position for Ag adsorption is hollow site. The O2 adsorption energy dramatically increased from 0.298eV to 1.108eV due to Ag pre-adsorbed. It is Ag pre-adsorbed that facilitates O2 adsorption on surface. The bond length and bond population of O2 molecule indicate that Ag atom facilitates O2 molecule dissociative adsorption. The Ag atom strengthens LaMnO3(001) substrate activity and activity center was formed on surface, which enhances the electrocatalytic activity of LaMnO3 as solid oxide fuel cells cathode material at low temperature. [Copyright &y& Elsevier]

Abstract: Effect of characteristics of Sm0.2Ce0.8O1.9 (SDC) powder as a function of calcination temperature on the fabrication of dense and flat anode-supported SDC thin electrolyte cells has been studied. The results show that the calcination temperature has a significant effect on the particle size, degree of agglomeration, and sintering profiles of the SDC powder. The characteristics of SDC powders have a significant effect on the structure integrity and flatness of the SDC electrolyte film/anode substrate bilayer cells. The SDC electrolyte layer delaminates from the anode substrate for the SDC powder calcined at 600°C and the bilayer cell concaves towards the SDC electrolyte layer for the SDC powder calcined at 800°C. When the calcinations temperature increased to 1000°C, strongly bonded SDC electrolyte film/anode substrate bilayer structures were achieved. An open-circuit voltage (OCV) of 0.82–0.84V and maximum power density of ∼1Wcm−2 were obtained at 600°C using hydrogen as fuel and stationary air as the oxidant. The results indicate that the matching of the onset sintering temperature and maximum sintering rate temperature is most critical for the development of a dense and flat Ni/SDC supported SDC thin electrolyte cells for intermediate temperature solid oxide fuel cells. [Copyright &y& Elsevier]

Yttria-stabilized zirconia (YSZ) membranes were deposited onto porous NiO-YSZ anode supports by screen printing. Combined with LaSrMnO-YSZ composite cathode, the prepared anode-supported solid oxide fuel cells (SOFCs) were electrochemically tested. A typical SOFC with a 30-μm-thick YSZ electrolyte membrane gave the maximum power densities (MPDs) of 0.26, 0.53, 0.78, and 1.03 W/cm at 650, 700, 800, and 850 °C, respectively, using hydrogen as fuel and stationary air as oxidant. Replacement of stationary air with pure oxygen flow exerted a significant positive effect on the MPDs of the cell. Using 100- and 200-ml/min oxygen as oxidants, the MPDs of the cell were enhanced 35.3% and 68.6%, respectively. Polarization analysis indicated that, at the MPD points, the electrode polarization resistances accounted for 80% of the cell total resistances. [ABSTRACT FROM AUTHOR]

Abstract: A single-chamber solid oxide fuel cell made of Ni/YSZ anodes, YSZ electrolytes and SDC-impregnated LSM cathodes was tested in methane–oxygen mixture at furnace temperature equal to 700°C. Two Ag wires were arranged on the anode surface to in situ measure the changes of the local anode resistance (R s) during testing. Oscillations of the R s, the cell voltage and the actual temperature of the cell were observed and attributed to Ni/NiO redox cycles. Steady-state tests of the cell showed the corresponding oscillation patterns mainly depended on methane-to-oxygen ratio (M =1, 2). Higher current density (J) to a certain extent could suppress NiO reduction and promote Ni oxidation. Scanning electron micrographs confirmed that Ni/NiO redox cycles had occurred mainly near the anode surface. The obtained results imply that gradual reoxidation of the Ni-anodes accompanying the various oscillation behaviors plays an important role in the degradation of the SC-SOFCs, especially under oxidation conditions. [Copyright &y& Elsevier]

The Seebeck coefficient is a function of carrier concentration and configurational entropy. In this report, we semi-theoretically investigate the Seebeck coefficient of LnCaMnO (Ln=Rare-earth) perovskites based on the electronic structure of the 3 d orbitals of Mn ions, using the developed Heikes model, Boltzmann transport model, and diffusion model. The results show that the Seebeck coefficient of such a strongly correlated electron system in paramagnetic state is remarkably affected by site degeneracy. As temperature decreases, the evolution of the spin and orbital degrees of freedom together with the change in phonon scattering mode describes the Seebeck coefficient behavior satisfactorily. The phonon drag effect at low temperature is also discussed. [ABSTRACT FROM AUTHOR]

Abstract: Cu is incorporated by vacuum-assisted electroless plating into porous Ni/Sm0.2Ce0.8O1.9 (Ni/SDC) anodes as the active anodes for the oxidation reaction of hydrogen and methane of intermediate temperature solid oxide fuel cells (IT-SOFCs). The scanning electron microscopy (SEM) observation indicates the formation of a uniformly distributed nano-structured Cu network within the porous Ni/SDC microstructure. The maximum power density of the cell with the Cu electroless-plated Ni/SDC anodes is 0.84 and 0.54 W cm−2 in dry H2 and dry CH4 at 600 °C, respectively, enhanced by ∼30% as compared to the cell with conventional Ni/SDC anodes. The increase in the performance of the cell with the Cu electroless-plated Ni/SDC anodes is most likely attributed to the enlarged effective three-phase boundaries (TPBs) by interconnecting the isolated Ni and/or SDC particles with the electroless-plated Cu network and the formation of TPBs at the Cu/SDC interface due to the activation of SDC surface by the Cu deposition. The stability test shows that cell degradation in dry methane due to carbon deposition is significantly reduced by the electroless copper plating. [Copyright &y& Elsevier]

Abstract: The electrolyte materials Ce0.85Sm0.15O1.925–x at.% FeO1.5 (x =0, 0.5, 1, 2, 3) were synthesized by means of glycine–nitrate process (GNP). Their structures and ionic conductivities were characterized by X-ray diffraction, SEM and AC impedance spectroscopy. All the electrolytes were found to be ceria-based solid solutions of fluorite type structures. Grain size increased with increased Fe2O3 content up to 0.5at.% and then became almost constant with further addition of Fe2O3. The grain-boundary resistance could be significantly decreased by small addition of Fe2O3. Electrolyte-supported solid oxide fuel cells (SOFC) fabricated with Ce0.85Sm0.15O1.925–x at.% FeO1.5 (x =0.5, 3) electrolytes were studied and compared with the fuel cell with Ce0.85Sm0.15O1.925 as electrolyte. [Copyright &y& Elsevier]

Abstract: Non-sealed solid oxide fuel cell (NS-SOFC) micro-stacks with two gas channels were fabricated and operated successfully under various CH4/O2 gas mixtures in a box-like stainless-steel chamber. The cells with an anode-facing-cathode configuration were connected in serial by zigzag sliver sheets. Each cell consisted of the Ni/yttria-stabilized zirconia (YSZ) anode, the YSZ electrolyte, and the Sm0.2Ce0.8O1.9-impregnated (La0.75Sr0.25)0.95MnO3 cathode. In this configuration, to ensure the identical gas distribution over the electrode surfaces, two gas channels with small vents flanking the stacks were used as gas channels of methane and oxygen for anodes and cathodes, respectively. The selectivity requirement of both the anode and cathode for the oxidation and reduction of CH4 and O2 was lowered and the sheets could extend the residence time of gas flow over the electrode surface. By the direct flame heat with a liquefied petroleum gas burner, the stacks presented a rapid start-up and full utilization of the exhaust gas. Eventually, an open-circuit voltage (OCV) of 1.8 V and maximum power output of 276 mW was produced by a two-cell stack. For a four-cell stack, a maximum power output of 373 mW was obtained. [Copyright &y& Elsevier]

Abstract: BaCo0.7Fe0.2Nb0.1O3−δ(BCFN)/Ce0.8Sm0.2O1.9(SDC) composite material was prepared and characterized as cathode for intermediate temperature solid oxide fuel cells. The X-ray diffraction result proved that there was no obvious reaction between the BCFN and SDC after calcination at 1000 °C for 10 h. AC impedance spectra based on La0.9Sr0.1Ga0.8Mg0.2O3−δ(LSGM) electrolyte measured at intermediate temperatures showed that a cathode with 30 wt% SDC exhibited the best electrochemical performance among the electrodes studied. The interfacial resistance value for BCFN/30SDC was as low as 0.0104, 0.017, 0.029, and 0.062 Ω cm2 at 800, 750, 700 and 650 °C, respectively. The maximum power density of a single cell with BCFN/30SDC cathode, Ni0.9Cu0.1-SDC anode, and LSGM/SDC electrolyte was 209.7, 298.2, 407.1, 543.4 and 697.9 mW cm−2 at 600, 650, 700, 750 and 800 °C. [Copyright &y& Elsevier]

Abstract: In this paper, Ce0.8Sm0.2O1.9 (SDC) nanoparticles modified GdBaCo2O5+δ (GBCO) cathodes were fabricated by an infiltration technique and evaluated for intermediate-temperature solid oxide fuel cells (IT-SOFCs). Good chemical compatibility between GBCO and infiltrated SDC was confirmed by X-ray diffraction (XRD) characterization. SDC nanoparticles (∼40 nm) formed continuous ionic-conducting phase on porous GBCO backbone, which contributed to significantly improved electro-catalytic property. At 600 °C, the composite cathode with 3.3 mg cm−2 SDC loading exhibited encouragingly low Rp value of 0.1 Ω cm2, which was much lower than 0.43 Ω cm2 of pure-GBCO cathode. As revealed by PO2 dependence of impedance spectra, the oxygen reduction reaction was mainly limited by charge-transfer processes. Furthermore, a stable operation of 80 h was obtained at 600 °C. Our study implies that infiltrated GBCO cathode is very attractive for application in IT-SOFC cathode. [Copyright &y& Elsevier]