Effect of thickness of Gd0.1Ce0.9O1.95 electrolyte films on electrical performance of anode-supported solid oxide fuel cells

In the present paper, we investigated the electrical performance of anode-supported solid oxide fuel cells (SOFCs) composed of Gd_0.1Ce_0.9O_1.95 (GDC) electrolyte films of 1-75 μm in thickness prepared by simple and cost-effective methods (dry co-pressing process and spray dry co-pressing process), and discussed the effect of thickness of the GDC electrolyte films on the electrical performance of the anode-supported SOFCs. It was shown that reducing the thickness of the GDC electrolyte films could increase the maximum power densities of the anode-supported SOFCs. The increase of the maximum power densities was attributed to the decrease of the electrolyte resistance with reducing the electrolyte thickness. However, when the thickness of the GDC electrolyte films was less than a certain value (approximately 5 μm in this study), the maximum power densities decreased with the decrease in the thickness of the GDC electrolyte films. The calculated electron fluxes through the GDC electrolyte films increased obviously with reducing the thickness of the GDC electrolyte films, which was the reason why the maximum power densities decreased. Therefore, for anode-supported SOFCs based on electrolytes with mixed electronic-ionic conductivity, there was an optimum electrolyte thickness for obtaining higher electrical performance.     

Effect of metal ion location in reaction medium on formation process and structure of PtCu–CuO nanoparticles supported on carbon and γ-Fe2O3

The process of nanoparticle formation by radiochemical synthesis in a heterogeneous system has been investigated considering the effects of the metal ion location in the reaction medium. PtCu nanoparticles supported on carbon and γ-Fe₂O₃ were synthesized using a high-energy electron beam. The metal ions in the precursor were categorized as those dissolved in solution, adsorbed on support, and precipitated. The ratio of metal ions in the solution was varied prior to the electron beam irradiation and its effects on the synthesized particle structures were examined. The nanoparticles were characterized by inductively coupled plasma-atomic emission spectrometry, transmission electron microscopy, X-ray diffraction, and X-ray absorption spectroscopy. A PtCu alloy and CuO were immobilized on the support in all the samples. The PtCu alloy nanoparticle composition depended on the Cu ion content in the solution. The nanoparticle formation mechanism could be explained using the obtained results. Metal ions present in the solution resulted in formation of the alloy. The adsorbed ions also contributed to the alloy formation by desorbing from the support when irradiated. On the other hand, alloy formation with Pt from the precipitated Cu ions was found to be difficult.     

Electrical conductivity,Seebeck coefficient,and defect structure of oxygen nonstoichiometric Nd2−xSrxNiO4+δ

To elucidate the electronic state and the conduction mechanism of Nd₂NiO_4+δ series oxides at high temperatures, the electrical conductivity, Seebeck coefficient, and nonstoichiometric oxygen content of Nd_2−xSr_xNiO_4+δ (x = 0, 0.2, 0.4) were measured as a function of the Sr content, temperature, and oxygen partial pressure. The hole mobility is estimated from the electrical conductivity and the hole concentration which is defect chemically determined. The mobility slightly decreases as temperature increases as in metals at high temperatures. The relationships between the Seebeck coefficient, electrical conductivity, and hole concentration can be explained by Mott's equation, which expresses the Seebeck coefficient for metals. Semi-quantitative analyses strongly indicate that the electron or hole is itinerant in Nd_2−xSr_xNiO_4+δ, and the conduction mechanism is metal-like band conduction at high temperatures. Based on the experimental results, schematics for energy level and band structure are proposed. At high temperatures, free holes in the σ_x2−y2 band composed of d_x2−y2 orbitals contribute to metallic conduction.     

Molecular Classification and Overcoming Therapy Resistance for Acute Myeloid Leukemia with Adverse Genetic Factors

The European LeukemiaNet (ELN) criteria define the adverse genetic factors of acute myeloid leukemia (AML). AML with adverse genetic factors uniformly shows resistance to standard chemotherapy and is associated with poor prognosis. Here, we focus on the biological background and real-world etiology of these adverse genetic factors and then describe a strategy to overcome the clinical disadvantages in terms of targeting pivotal molecular mechanisms. Different adverse genetic factors often rely on common pathways. KMT2A rearrangement, DEK-NUP214 fusion, and NPM1 mutation are associated with the upregulation of HOX genes. The dominant tyrosine kinase activity of the mutant FLT3 or BCR-ABL1 fusion proteins is transduced by the AKT-mTOR, MAPK-ERK, and STAT5 pathways. Concurrent mutations of ASXL1 and RUNX1 are associated with activated AKT. Both TP53 mutation and mis-expressed MECOM are related to impaired apoptosis. Clinical data suggest that adverse genetic factors can be found in at least one in eight AML patients and appear to accumulate in relapsed/refractory cases. TP53 mutation is associated with particularly poor prognosis. Molecular-targeted therapies focusing on specific genomic abnormalities, such as FLT3, KMT2A, and TP53, have been developed and have demonstrated promising results.     

Quantitative determination of 1,2-diacylglycerol in thoracic aorta of the rat using latroscan TLC/FID: Effect of norepinephrine

This study was undertaken to evaluate the use of the Iatroscan TLC/FID system for quantitating 1,2-diacylglycerol (DG) in the aorta. Cholesteryl acetate was chosen as an internal standard. In order to avoid interference of triglyceride and phospholipids with the separation of the internal standard and 1,2-DG, a stepwise elution of lipids from the silicic acid column was used. The development of Chromarods was done using two solvent systems and a three-step developing technique. Assay and recovery of both 1,2-DG and cholesterol (as compared to cholesteryl acetate) were sufficient to measure changes in the 1,2-DG content in blood vessels. After exposing the thoracic aorta to 10⁻⁵ M norepinephrine for 10 min, the 1,2-DG content increased nearly two-fold without significant change in cholesterol content.     

Comparison of various mixtures of β-chitin and chitosan as a scaffold for three-dimensional culture of rabbit chondrocytes

With the use of a recently created chitosan neutral hydrogel, we have been able to create various mixtures of chitin and chitosan without changing their characteristics even at room temperature. The aim of this study was the initial comparison of various mixtures of β-chitin and chitosan as a scaffold for rabbit chondrocyte culture. We created five types of sponges: pure β-chitin, pure chitosan, 3:1, 1:1, and 1:3 β-chitin-chitosan. The absorption efficiencies of chondrocytes in all five types of sponges were found to be around 98%. The mean concentrations of chondroitin sulfate were statistically different neither at week 2 nor at week 4 postculture between the types of sponges. The content of hydroxyproline in the β-chitin sponge was significantly greater than in other sponges at week 4 postculture. From the histochemical and immunohistochemical findings, the cartilage-like layer in the chondrocytes-sponge composites of all five types of sponges was similar to hyaline cartilage. However, only immunohistochemical staining of type II collagen in the pure β-chitin sponge was closer to normal rabbit cartilage than other types of sponges. The pure β-chitin sponge was superior to other sponges concerning the content of extracellular matrices of collagen.     

Characterization of Amylose Nanogels and Microgels Containing Ionic Polysaccharides

We prepared and characterized amylose nanogels containing ionic polysaccharides which we used were 4-O-methyl-D-glucurono-D-xylan (GX), alginate, xanthan, and chitosan. Gelation under a shear force followed by a wet pulverization leads to the formation of hybrid nanogels. The resultant nanogels were characterized by particle size analysis, zeta-potential measurement and atomic force microscopy (AFM). Wet pulverization under a pressure of 200 MPa reduced the particle size of the gels from 20−26 μm to 240−670 nm. Zeta potential measurement showed that the ionic polysaccharides increased surface charges of the amylose gels. AFM observations showed the network consisting of submicron size amylose-polysaccharide nano fibrils. The fibrils containing GX were dispersed uniformly, while those containing only amylose were partly aggregated.     

Redox behavior of palladium at start-up in the Perovskite-type LaFePdOx automotive catalysts showing a self-regenerative function

In order to elucidate the superior start-up activity of LaFePdO_x catalysts in practical automotive emission control, the redox property of Pd species in a Perovskite-type LaFe_0.95Pd_0.05O₃ catalyst was studied at temperatures ranging from 100 to 400 °C using X-ray spectroscopic techniques. In a reductive atmosphere, and even at temperatures as low as 100 °C, Pd⁰ species is partially segregated out onto the catalyst surface from the B-site of the Perovskite-type matrix of LaFe_0.95Pd_0.05O₃. Passing through successive oxidizing atmospheres, the segregated Pd⁰ species is re-oxidized into Pd²⁺ at 200–300 °C. The formation of a solid solution between the re-oxidized Pd species and the Perovskite-type matrix begins to be seen at around 400 °C and accelerates at higher temperatures. Thus a quasi-reversible redox reaction between the surface Pd⁰ and the cationic Pd in the LaFe_0.95Pd_0.05O₃ matrix takes place. The start-up activity of LaFePd_xO_x catalysts can be attributed to Pd⁰ that segregates under the reductive atmosphere which is a natural part of the redox fluctuation in automotive exhaust gases at 100–200 °C.