Cloning and characterization of a β-N-acetylglucosaminidase (BmFDL) from silkworm Bombyx mori

In insects, β-N-acetylglucosaminidase (GlcNAcase) participates in critical physiological processes such as fertilization, metamorphosis, and glycoconjugate degradation. Insects produce glycoproteins carrying paucimannosidic-type N-glycans, the terminal GlcNAc residue of which is cleaved by a GlcNAc-linkage specific GlcNAcase, also known as the fused lobes (FDL) protein. To obtain information on the structure of GlcNAcases and insight into their contribution to physiological processes, we cloned Bombyx mori FDL (BmFDL) from silkworm larvae. The full-length cDNA (1.9 kb) encoded a protein of 633 amino acids with 42% amino acid sequence identity to Drosophila melanogaster FDL (DmFDL). Recombinant BmFDL cleaved only β-1,2-linked GlcNAc residues from the α-1,3 branch of biantennary N-glycan. This substrate specificity was similar to that of DmFDL. Microsomal FDL activity was inhibited by anti-BmFDL antibodies. Taken together, our results suggest that BmFDL is a N-glycan-processing GlcNAcase in B. mori.     

Development of function-graded proton exchange membrane for PEFC using heavy ion beam irradiation

The graded energy deposition of heavy ion beam irradiation to polymeric materials was utilized to synthesize a novel proton exchange membrane (PEM) with the graded density of sulfonic acid groups toward the thickness direction. Stacked Poly(tetrafluoroethylene-co-hexafluoropropylene) (FEP) films were irradiated by Xe⁵⁴⁺ ion beam with the energy of 6 MeV/u under a vacuum condition. The induced trapped radicals by the irradiation were measured by electron spin resonance (ESR) spectroscopy. Irradiated films were grafted with styrene monomer and then sulfonated. X-ray photo-electron spectroscopy (XPS) spectra showed that the densities of sulfonic acid groups were controlled for injection “Surface” and transmit “Back” sides of the fabricated PEM. The membrane electrode assembly (MEA) fabricated by the function-graded PEM showed improved fuel cell performance in terms of voltage stability. It was expected that the function-graded PEM could control the graded concentration of sulfonic acid groups in PEM.     

Thermomagnetic Effects in High-Mobility PbTe Films

The narrow-gap compound semiconductor PbTe has high Hall mobility. The Fermi surface at the L-point in the Brillouin zone has large anisotropy. In this work, we measured thermomagnetic effects in PbTe thin films to confirm anisotropy of the Nernst coefficient A _Ne and show Nernst mobility from the ratio of A _Ne and the Seebeck coefficient S: μ _Ne = A _Ne/S. Angular dependences of the Nernst voltage show that A _Ne is independent of the angle between the temperature gradient and the magnetic field, because of the high L-point symmetry. The calculated Nernst mobility was compared with the Hall mobility. Because the former is smaller, the Mott equation cannot explain the Seebeck coefficient at room temperature.     

Oxidation behavior of copper nanoparticles at low temperature

A mass gain for copper nanoparticles with a mean diameter of 20 nm in a 20% oxygen-nitrogen atmosphere was measured at 150-300 °C using thermogravimetry (TG). The mass gain equilibrium of the copper particles differed at each temperature, and a threshold temperature was recorded. Oxide products, consisting mainly of Cu₂O, formed on the copper nanoparticles below the threshold temperature. Above the threshold temperature, there was an initial, and drastic, formation of Cu₂O, which then changed to CuO. The activation energy for the oxidation of the copper nanoparticles that could be calculated from the rate of the mass gain was an indication of the nano-effect of the copper nanoparticles.     

Effect of surface properties of silica nanoparticles on their cytotoxicity and cellular distribution in murine macrophages

In this study, complexes composed of poly-l-tyrosine (pLT) and single-walled carbon nanotubes (SWCNTs) were produced and the dispersibility of the pLT/SWCNT complexes in water by measuring the ζ potential of the complexes and the turbidity of the solution were investigated. It is found that the absolute value of the ζ potential of the pLT/SWCNT complexes is as high as that of SWCNTs modified with double-stranded DNA (dsDNA) and that the complexes remain stably dispersed in the water at least for two weeks. Thermogravimetry analysis (TGA) and visualization of the surface structures of pLT/SWCNT complexes using an atomic force microscope (AFM) were also carried out.     

A study of decoupling with skeleton matrix in two‐degree‐of‐freedom generalized minimum variance control

There are many multi‐input multi‐output (MIMO) systems in chemical plants, and they have multiple time delays of different length in each input and output pair. This paper explains a two‐degree‐of‐freedom (2DOF) control system based on generalized minimum variance control (GMVC) for MIMO systems. It can improve the tracking performance with respect to the reference signals and the response properties for the disturbance. The states between the sampling period can be expressed by using the modified z transform to take account of multiple time delays. Additionally, a tracking controller is designed to decouple the plant. © 2011 Wiley Periodicals, Inc. Electr Eng Jpn, 176(1): 28–36, 2011; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/eej.21046     

Self-healing capability of porous polymer film with corrosion inhibitor inserted for corrosion protection

Porous polymer films with varying pore sizes were prepared by changing the evaporation time of an organic solvent. A specimen was prepared consisting of porous polymer film containing corrosion inhibitor coated onto carbon steel. The specimens were scratched with a knife-edge, and the polarization resistance was monitored in a sodium chloride solution. An increase in polarization resistance was confirmed, and the films with larger-sized pores demonstrated a higher self-healing capability.