Fabrication of BSCF-based mixed oxide ionic-electronic conducting multi-layered membrane by sequential electrophoretic deposition process

The Ba_0.5Sr_0.5Co_0.8Fe_0.2O_3-δ (BSCF)-based multi-layered oxygen separation membrane was fabricated by the sequential electrophoretic deposition (EPD) process. A thin porous/dense bi-layer of BSCF was formed on a thick porous support of BSCF. The porous support prepared by a sacrificial template method using BSCF powder mixed with wheat starch (30 wt%) as a pore-forming agent, followed by uniaxial pressing and low-temperature sintering, was directly used as an EPD electrode. A thin BSCF layer was first formed on the porous support, and then a thin BSCF + PMMA (polymethyl methacrylate) layer was sequentially formed on the thin BSCF layer using a bimodal suspension of BSCF and PMMA. A 30-μm thin porous/dense bi-layer of BSCF of which the total thickness was obtained by optimizing the processes of EPD and subsequent co-sintering. The oxygen separation performance of 3.7 ml (STP) min^?1 cm^?2 at 860 °C was achieved for the BSCF-based multi-layered oxygen separation membrane.     

Structures and electronic properties of surface/edges of nanodiamond and nanographite

The structure, electronic and magnetic properties of nanodiamond and nanographite/nanographene are investigated. Detonation nanodiamond particles that are covered with amorphous graphitic composites are hydrothermally treated to remove the graphitic surface composites and to terminate the surface carbon atoms with hydrogen. The number of localized spins of dangling bonds and the hydrogen concentration increase upon the increase in the hydrothermal treatment time up to 40 h. Above 40 h, both drop discontinuously, a surface structural reconstruction was suggested. The creation of dangling bonds and an incomplete hydrogenation of the surface carbon atoms destabilize the surface, resulting in the structural reconstruction. Nanodiamond particles are thermally converted to nanographite/nanographene. A single nanographene sheet is successfully prepared by heat-treating nanodiamond particles. The edge of graphene sheet with its edge carbon atoms being hydrogen-terminated is investigated by UHV-STM/STS. Zigzag edges are found to have non-bonding π-state of edge origin, in good agreement with theoretical prediction.     

A Metal-Free,Disulfide Oxidized Form of Superoxide Dismutase 1 as a Primary Misfolded Species with Prion-Like Properties in the Extracellular Environments Surrounding Motor Neuron-Like Cells

Superoxide dismutase 1 (SOD1) is a metalloenzyme with high structural stability, but a lack of Cu and Zn ions decreases its stability and enhances the likelihood of misfolding, which is a pathological hallmark of amyotrophic lateral sclerosis (ALS). A growing body of evidence has demonstrated that misfolded SOD1 has prion-like properties such as transmissibility between cells and intracellular propagation of misfolding of natively folded SOD1. Recently, we found that SOD1 is misfolded in the cerebrospinal fluid of sporadic ALS patients, providing a route by which misfolded SOD1 spreads via the extracellular environment of the central nervous system. Unlike intracellular misfolded SOD1, it is unknown which extracellular misfolded species is most relevant to prion-like properties. Here, we determined a conformational feature of extracellular misfolded SOD1 that is linked to prion-like properties. Using culture media from motor neuron-like cells, NSC-34, extracellular misfolded wild-type, and four ALS-causing SOD1 mutants were characterized as a metal-free, disulfide oxidized form of SOD1 (apo-SOD1^S-S). Extracellular misfolded apo-SOD1^S-S exhibited cell-to-cell transmission from the culture medium to recipient cells as well as intracellular propagation of SOD1 misfolding in recipient cells. Furthermore, culture medium containing misfolded apo-SOD1^S-S exerted cytotoxicity to motor neuron-like cells, which was blocked by removal of misfolded apo-SOD1^S-S from the medium. We conclude that misfolded apo-SOD1^S-S is a primary extracellular species that is linked to prion-like properties.     

Adsorption of amino acids by fullerenes and fullerene nanowhiskers

We have investigated the adsorption of some amino acids and an oligopeptide by fullerene (C₆₀) and fullerene nanowhiskers (FNWs). C₆₀ and FNWs hardly adsorbed amino acids. Most of the amino acids used have a hydrophobic side chain. Ala and Val, with an alkyl chain, were not adsorbed by the C₆₀ or FNWs. Trp, Phe and Pro, with a cyclic structure, were not adsorbed by them either. The aromatic group of C₆₀ did not interact with the side chain. The carboxyl or amino group, with the frame structure of an amino acid, has a positive or negative charge in solution. It is likely that the C₆₀ and FNWs would not prefer the charged carboxyl or amino group. Tri-Ala was adsorbed slightly by the C₆₀ and FNWs. The carboxyl or amino group is not close to the center of the methyl group of Tri-Ala. One of the methyl groups in Tri-Ala would interact with the aromatic structure of the C₆₀ and FNWs. We compared our results with the theoretical interaction of 20 bio-amino acids with C₆₀. The theoretical simulations showed the bonding distance between C₆₀ and an amino acid and the dissociation energy. The dissociation energy was shown to increase in the order, Val < Phe < Pro < Asp < Ala < Trp < Tyr < Arg < Leu. However, the simulation was not consistent with our experimental results. The adsorption of albumin (a protein) by C₆₀ showed the effect on the side chains of Try and Trp. The structure of albumin was changed a little by C₆₀. In our study Try and Tyr were hardly adsorbed by C₆₀ and FNWs. These amino acids did not show a different adsorption behavior compared with other amino acids. The adsorptive behavior of mono-amino acids might be different from that of polypeptides.     

Effect of CNTs on morphology and electromagnetic properties of non-firing CNTs/silica composite ceramics

Carbon composite ceramics have much attention for industry because of their excellent properties such as strong toughness, high electrical conductivity as well as low percolation threshold. Therefore, carbon nanotubes (CNTs) were used to incorporate with silica ceramics in order to improve their electromagnetic properties. The amount of CNTs in CNTs/silica composite ceramics was varied in order to investigate its effect on morphologies and electromagnetic properties of those. The composites were successfully fabricated by non-firing process. The results revealed that the obtained CNTs/silica composite ceramic have an electrical resistivity of 66.6?Ω·cm with a bending strength of 13.8?MPa. At the same time, the electromagnetic wave absorption ability achieved 70% over a wild frequency. This indicates that the CNTs in CNTs/silica composite ceramics may be potentially applied for an electromagnetic wave reflective material.     

Effect of silane modification on CNTs/silica composites fabricated by a non-firing process to enhance interfacial property and dispersibility

Carbon nanotube/ceramic composites have been in the spotlight thanks to their excellent properties. Sintering is the vital part of ceramics fabrication in terms of reliability, however sintering the carbon nanotube (CNT) based ceramic composites is a challenging task. In this study, interfacial bonding of silane functionalized CNT with silica ceramic is investigated by a non-firing sintering process. CNTs are first treated by a mixed acid with the aid of a silane 3-aminopropyl triethoxysilane (APTES), which improves the chemical bonding and dispersibility of CNT in ceramic bodies. The extent of APTES chemical functionalization and mechanical property of CNT/silica ceramic composites are characterized using Raman spectrometer, FT-IR analysis, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and three-point bending strength measurement. Results show that composites are successfully prepared without sintering with stable CNT-silica interface, superior dispersibility, and good mechanical properties.     

Manipulating the chemical affinity and kinetics of 3D silica particle network via the phase-separation technique

We developed a simple and versatile technique for a particle’s self-organizing-network based on a non-solvent induced micro-phase separation (NIPS). When a good solvent vaporizes from a particle dispersion in a ternary solution including the polymer, good solvent and non-solvent, the suspension is separated into the polymer network and non-solvent phase. If the affinity between the particles and polymer is sufficient enough, the particles are entrapped in the polymer network and particle network can be achieved. To expand this technique to particles with various physical properties, the surface of the particles was identified using the Hansen dispersibility parameter (HDP). From a comparison of the HDP of the unmodified and modified silica, an NH₂ group is suitable for entrapment of the silica by cellulose acetate as the polymer. However, with an increase in number of the silica particles, entrapment of the silica in the polymer was prevented. Control of the phase separation rate by the lowering temperature leaded to entrapment of silica particles in the polymer network. The proposed technique is effective not only for spherical oxide particles, but also for non-oxides, various shapes and structures. Depending on particle characteristics, functional films and bulk materials for thermal insulation, light diffusion, and electro conductivity can be obtained.     

Thermal conductivity analysis using three‐dimensional microstructures of gelation freezing derived cellular mullite

The relationship between thermal conductivity and unidirectional cellular mullite microstructures created with the freeze casting route is discussed using actual three‐dimensional (3D) images, in which a homogenization method was conducted with microscopic models created from 3D images, the temperature variation in macroscopic models by the finite element method (FEM), and local heat conduction in microscopic models. The simulation results were consistent with the experimental results. This image‐based modeling technique was thus confirmed to be a strong tool for the prediction of various thermal properties of porous ceramics.     

The study on change of mechanical properties of NBR due to deterioration

Rubber is an important industrial material. However, mechanical properties and deformation of the high polymer including rubber are not clear. A method of estimating the mechanical properties which can be used for the deteriorated rubber is demanded to improve the reliability of it. Improved VBO (Viscoplasticity theory based on overstress) model is a constitutive equation. We applied it for the compression stress-strain behavior of deteriorated NBR (acryloNitrile-Butadiene rubber). Furthermore, we proposed a method of estimating the mechanical properties of deteriorated NBR. In this paper, deterioration tests in water and in air were conducted. To confirm the validity of the proposed improved VBO model and estimated mechanical properties, simulations of the stress-strain curves obtained in the tests were conducted.     

Estimation and characterisation of major royal jelly proteins obtained from the honeybee Apis merifera

Royal jelly (RJ) contains many components, including proteins. We focused on major royal jelly proteins (MRJPs) under natural conditions, and attempted to determine the content ratios and molecular forms of MRJPs by size-exclusion HPLC, SDS–PAGE, 2-DE and MALDI TOF/TOF MS. Soluble RJ proteins were extracted by dialysis followed by several centrifugation techniques. Soluble RJ proteins were universally separated into five peaks (640 kDa, 280 kDa, 100 kDa, 72 kDa and 4.5 kDa) by size-exclusion HPLC on a Superose 12 column. Among these peaks, both the 280 kDa and 72 kDa peaks were major, but the intensity of the 280 kDa peak differed markedly among original RJ samples (n = 70). The main 280 kDa protein was separated into a 55 kDa band by reducing and non-reducing SDS–PAGE. This protein was also separated into multiple spots ranging from pH 4.2 to 6.5 by 2-DE. These spots were identified as MRJP 1 by MALDI TOF/TOF MS. From these results, MRJP 1 was thought to comprise an oligomer complex linked by non-covalent bonds under natural conditions. Another major protein, the 72 kDa peak on Superose 12 HPLC, was identified as MRJP 2.