Effect of heat treatment on bend stress relaxation of pure tungsten

Bend stress relaxation (BSR) tests at temperatures of 500, 600, 800, 900 and 1000 °C for 0.1, 0.5 and 1 h in vacuum were performed on the pure tungsten after heat treatment for stress relief at 900 °C for 1 h. The degree of stress relaxation increased with test temperature. The BSR ratio of the heat treated specimen was larger than that of the as-received specimen at this temperature region. Small reduction in the BSR ratio was observed at the temperatures of 500, 600 and 800 °C. The BSR ratio of the heat treated specimen decreased significantly at the temperatures of 900 and 1000 °C and it was close to that of the as-received specimen. The BSR ratio of the heat treated specimen and the as-received specimen exhibited similar trend of time-evolution. The stress was exponentially relaxed with increasing test time. The BSR ratio decreased significantly in a short time below 0.1 h, and then decreased slowly. Higher activation energy of stress relaxation evaluated by cross-cut method was obtained for the higher temperature.     

Organization of the capsule biosynthesis gene locus of the oral streptococcus Streptococcus anginosus

The capsular polysaccharide (CPS) of the important oral streptococcus Streptococcus anginosus, which causes endocarditis, and the genes for its synthesis have not been clarified. In this study, we investigated the gene locus required for CPS synthesis in S. anginosus. Southern hybridization using the cpsE gene of the well-characterized bacterium S. agalactiae revealed that there is a similar gene in the genome of S. anginosus. By using the colony hybridization technique and inverse PCR, we isolated the CPS synthesis (cps) genes of S. anginosus. This gene cluster consisted of genes containing typical regulatory genes, cpsA-D, and glycosyltransferase genes coding for glucose, rhamnose, N-acetylgalactosamine, and galactofuranose transferases. Furthermore, we confirmed that the cps locus is required for CPS synthesis using a mutant strain with a defective cpsE gene. The cps cluster was found to be located downstream the nrdG gene, which encodes ribonucleoside triphosphate reductase activator, as is the case in other oral streptococci such as S. gordonii and S. sanguinis. However, the location of the gene cluster was different from those of S. pneumonia and S. agalactiae.     

Elution of sodium caseinate from agar-based gel matrixes in simulated gastric fluids

Elution of sodium caseinate from agar/psyllium composite gels was investigated in simulated gastric fluids to determine predominant mechanical parameters of gels for the elution kinetics and to predict the kinetics using the parameters. When the concentration of agar was fixed at 0.5% in the composite gels, elastic moduli determined by creep tests decreased with increasing concentration of psyllium, while viscosities increased. Compression load upon syringing through an enteral tube increased with increasing concentration of psyllium, whereas the surface-volume diameter d_3,2 of gel particles after syringing decreased. The elution kinetics of sodium caseinate from cylindrical gels was described using two different diffusion coefficients; D₁ and D₂ (D₁ > D₂) and the diameter of gels. Both diffusion coefficients decreased with increasing concentration of psyllium, resulting in 1.9 × 10⁻⁶ (for D₁) and 6.7 × 10⁻⁸ (for D₂) cm²/min by 1.5% addition, which corresponded to approx. 30% and 45% of the control (i.e., 0% psyllium), respectively. The fraction ratio of sodium caseinate having D₁ was not sensitive to psyllium concentration; approx. 80%–85% in the concentration range tested. D₁ was inversely proportional to viscosities determined by creep tests, particularly one from the Voigt body η₁ in the 4-element mechanical model. When cube gels were divided into smaller ones without changing the total volume, elution rates were inversely proportional to the cube length, where the diffusion coefficients did not change. The elution kinetics of sodium caseinate from the gel matrixes was anticipated using η₁ of gels before syringing and d_3,2 of gel particles after syringing when the usage of gels for percutaneous endoscopic gastrostomy is assumed.     

Faecal fermentation of partially hydrolyzed guar gum

Partially hydrolyzed guar gum (PHGG) remains undigested in the upper gastrointestinal tract, but is fermented by bacteria in the large intestine to stimulate short-chain fatty acids, particularly butyric acid. In this study, the bacterial composition in the in vitro faecal fermentation of PHGG was analyzed by real-time PCR to identify the bacteria contributing to the stimulation of butyric acid production. The production of short-chain fatty acids in a PHGG culture was compared with that in inulin and blank (no substrate) cultures. After the fermentation of the substrates by fresh human faeces, PHGG clearly promoted the production of butyric acid. The butyryl-CoA CoA-transferase gene copy number and the 16S rRNA gene copy number of the Roseburia/Eubacterium rectale group in the PHGG culture were significantly higher than those in the blank culture. These results indicated that Roseburia/E. rectale group bacteria would play an important role in the butyric acid production in vitro fermentation of PHGG.     

Enhanced localized near field and scattered far field for surface nanophotonics applications

The scattering physics of photons is traced back to Rayleigh scattering theory in 1871 and Mie scattering theory in 1908. However, the scattering near field and far field have recently emerged again as a new fundamental physics and innovative nanoprocessing technology in quantum electronics and photonic devices. An enhanced near field generated by plasmonic particles can concentrate optical energy into a nanoscale space as a nanolens even with near infrared laser pumping. This plasmonic nanophotonics extends the existing optical science to a new class of photonics inclusive of surface enhanced Raman scattering, nanoprocessing of advanced electronic and photonic materials, etc. The Mie scattering near field also opens up new fields. The Anderson localization of light in a planar random photonic crystal laser is also a new class of quantum electronics devices, where Slow Bloch Mode is scattered by artificial structural randomness in a photonic crystal. In this contribution we will review the recent efforts of our scattering photonics research, which have resulted in significant advances in the plasmonic surface photonics of near-field and far-field nano/micro photonics and the Anderson localization in random lasing.     

Synchronous and separate homo-crystallization of enantiomeric poly(l-lactic acid)/poly(d-lactic acid) blends

High-molecular-weight poly(l-lactic acid) (PLLA) and poly(d-lactic acid) (PDLA) are blended at different ratios and their crystallization behavior was investigated. Solely homo-crystallites mixtures of PLLA and PDLA were synchronously and separately formed during isothermal crystallization in the temperature (T_c) range of 90–130 °C, irrespective of blending ratio, whereas in addition to homo-crystallites, stereocomplex crystallites were formed in the equimolar blends at T_c above 150 and 160 °C. Interestingly, in isothermal crystallization at T_c = 130 °C, the spherulite morphology of blends became disordered, the periodical extinction (periodical twisting of lamellae) in spherulites disappeared, and the radial growth rate of spherulite (G) of the blends was reduced by the synchronous and separate crystallization of PLLA and PDLA and the coexistence of PLLA and PDLA homo-crystallites. However, the interplane distance (d), the crystallinity (X_c), the transition crystallization temperature (T_c) from α′-form to α-form, the alternately stacked structure of the crystalline and amorphous layers, and the nucleation mechanism were not altered by the synchronous and separate crystallization of PLLA and PDLA and the coexistence of PLLA and PDLA homo-crystallites. The unchanged d, X_c, transition T_c, long period of stacked lamellae, and nucleation mechanism strongly suggest that the chiral selection of PLLA or PDLA segments on the growth sites of PLLA or PDLA homo-crystallites to some extent was performed during solvent evaporation and this effect remained even after melting.     

Trace precious metal Pt doped plate-type anodic alumina Ni catalysts for methane reforming reaction

A novel plate-type anodic alumina supported 17.9 wt% Ni/Al₂O₃/alloy showed a quick deactivation in daily start-up and shut down (DSS) steam reforming of methane (SRM) at 700 °C, because of the Ni oxidation reaction with steam. When 0.078 wt% Pt was doped, the catalyst exhibited self-activation and self-regeneration ability, while 3000 h continual and 500-time DSS stability was testified. Further, this Pt–Ni catalyst also showed excellent reactivity during carbon dioxide reforming of methane (CMR) and partial oxidation of methane reaction (POM). According to the TPR and XRD analyses, the H₂ spillover effect and the formation of Pt–Ni alloy were believed to be the main reason for the reactivity improvement of this catalyst.     

An investigation of two xylan‐degrading enzymes and a novel xylanase inhibitor in malted barley

Two enzymes with activity on xylan and xylan‐based substrates were isolated from malted barley. One appears to be relatively anionic and the other more cationic. Both are endo‐acting enzymes. The first of these was studied in more detail and shown to be of molecular weight ca. 59,000 and capable of acting through the pH range 5–7.5. It is relatively heat tolerant, with 30% of its activity surviving for 30 min at 70 °C. A low‐molecular‐weight (ca. 1300) inhibitor of xylanase that developed during germination was investigated. Its potency was not lowered by treatment with proteolytic enzymes, but treatment with polyvinylpolypyrrolidone did reduce its impact. Ultraviolet spectrophotometry and Fourier transform infrared spectroscopy, as well as staining with Folin–Ciocalteu reagent, indicated the presence of phenolic species, while mass spectroscopy studies suggested the presence of arabinose and possibly poly‐hexose. The presence of material that stained with aniline phthalate would be consistent with the presence of reducing sugar in the inhibitor. Copyright © 2013 The Institute of Brewing & Distilling     

Water quality analysis in Lake Hachiroko,Japan, using ALOS AVNIR‐2 data

In recent years, remote sensing has been used to assessing water pollution distribution. In this study, water quality is analyzed using data collected by the Advanced Visible and Near Infrared Radiometer type‐2 (AVNIR‐2) of the Advanced Land Observing Satellite (ALOS) at various points in time. We carried out fuzzy regression analysis of the AVNIR‐2 data and direct measurements of local water quality. The relationship between the water quality data and the AVNIR‐2 data was analyzed by solving both the min and max problems. By comparing the maps of estimated water quality with actual distributions of water quality in the study area, we found that the method used in this study allows effective derivation of water quality conditions from AVNIR‐2 data, which provides 10‐m spatial resolution. Furthermore, by comparing the maps created using AVNIR‐2 data collected at different times, we obtained results suggesting temporal changes in water quality. We also compared the results obtained using data collected by the optical sensor of the Landsat thematic mapper (TM) with 30‐m resolution and those obtained using data collected by the active sensor of JERS‐1 synthetic aperture radar (SAR), and examined the differences in classification results resulting from differences in resolution and sensors. © 2013 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.