Assessment of safety and efficacy of pine bark extract in normal and ovariectomized mice

We evaluated the influence of pine bark extract (PBE) on organs, the cytochrome-P450 (CYP) activities in liver and estrogenic effects in normal and ovariectomized (OVX) female mice. The PBE did not affect organ weights and liver-function indexes (activities of alkaline phosphatase, aspartate amino transferase, and alanine amino transferase) at doses; 0.04%, 0.4%, and 2.0% PBE in the diet, in normal and OVX female mice. In the OVX mice, CYP1A1 activity was significantly higher in the 0.4% and 2.0% PBE groups than in the OVX control group, and in the 0.4% and 2.0% PBE groups were significantly higher than in the 0.04% PBE group. CYP1A2 and 3A4 activities were significantly higher in the 2.0% PBE group than in all other groups. The PBE did not affect uterine weight and femoral bone mineral density at all PBE doses. These results showed that the dose of PBE at the recommended human intake, had no toxic and estrogenic effects in normal female and OVX mice, however, it may need attention to use the excess intake of PBE with some drugs in postmenopausal women.     

Crystallographic and Microstructural Studies of Lath Martensitic Steel During Tensile Deformation

Significant crystallographic refinement was observed in the as-quenched lath martensitic steel during tensile deformation up to a strain of 20 pct. Crystallographic investigation by electron backscattering diffraction analysis coupled with the use of crystal plasticity model confirmed that the activation behavior of slip systems is inhomogeneous even within each martensite block. In particular, the activation behavior of slip systems is initially affected by the initial crystal orientation; however, the effect becomes negligible with increasing deformation. In addition, slip systems parallel to the lath plane are preferentially activated during elongation. Our results indicate that the nonuniform crystal rotation within individual blocks is induced not only by grain interaction phenomena but also by the anisotropic activity of slip systems. These are key factor that determines the grain refinement behavior in the as-quenched lath martensitic steel during deformation.     

One-pot synthesis and characterization of aliphatic poly(oxytetramethylene) ionene

One-pot synthesis of poly(oxytetramethylene) ionene (POI) composed of one dimethylammonium group in each repeating unit is described. POI was prepared by using the cationic polymerization of tetrahydrofuran, followed by the chain extension reaction of living poly(oxytetramethylene) (POTM) chain with N,N-dimethylaminotrimethylsilane. The weight average molecular weight of the ionene with bromide counter-anion (POI-Br) was 48,000 g/mol and the molecular weight of POTM between the ionic sites was ca. 2100. POI-Br showed polyelectrolyte behavior in polar solvent. The elastomeric film of POI-Br was prepared: its tensile strength at break and elongation at break were ca. 11 MPa and ca. 1900% at 19 °C, respectively. Small-angle X-ray scattering, differential scanning calorimetry and dynamic mechanical analysis suggested the formation of microphase-separated structure for POI-Br film.     

Metallization of UV‐cured acrylate resins by reduction of polymer‐incorporated cobalt ion

The surface of UV‐cured films of poly(ethylene glycol) diacrylate (PEGAc)/tetrahydrofurfuryl acrylate (THFAc) (weight ratio 100/0, 90/10, and 80/20) was metallized by the reduction of polymer‐incorporated cobalt chloride with aqueous sodium borohydride at 20°C. The electron probe microanalysis (EPMA) and X‐ray photoelectron spectroscopy measurement revealed that the cobalt ion, which was homogeneously distributed in the inner part of the film before reduction, migrated to both sides of the film, and then reduced to pure metal by the reduction treatment. The surface resistance of the UV‐cured PEGAc/THFAc film increased with increasing THFAc content. Especially, the trend was prominent at the glass side of the metallized films. The glass transition temperature of the cured resin measured by dynamic viscoelastic analysis slightly rose with an increase of THFAc content. The EPMA map of cobalt and carbon in the depth direction of the metallized film showed that the cobalt layer, generated at the glass side of the film with a higher THFAc content, contains more polymer component, in agreement with the order of surface resistance. The X‐ray diffraction analysis of the reduced films revealed that the degree of crystallinity of the generated cobalt was low. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 1627–1632, 2006     

Titanium–Silicon–Nitrogen Composites with High Wear Resistance in Water and in Artificial Sea Water

Titanium–silicon–nitrogen (Ti-Si-N) composites were produced from a mixture of Si₃N₄, titanium nitride (TiN), and titanium by spark plasma sintering to develop wear-resistant materials with good environmental and biological compatibilities in water and sea water. The Ti-Si-N composite consisted of Si₃N₄, TiN, and titanium metal-rich particles coated with TiSi _x . Results of sliding tests in water and in artificial sea water showed that the wear resistance of the Ti-Si-N composite was much better than that of the titanium metal.     

Ethical issues regarding individual data collection and utilization in community health care programs]

Response of a nerve fiber of low excitability to periodic stimulus pulses is studied with computer simulation of the Hodgkin-Huxley model. The excitability of the Hodgkin-Huxley model is reduced by decreasing the equilibrium potential for the sodium ion and by increasing the temperature, so that the decremental propagation of spikes occurs in the refractory period. It is shown that, as the period of stimulus pulses is decreased, the propagation length of the spikes is continuously changed, and period-doubling bifurcations occur. The response of a nerve fiber of low excitability is then qualitatively different from that of a normal fiber.     

Electric stability of spatiotemporal stripe patterns formed by silver and antimony co-electrodeposition under the constant current mode

During Ag/Sb (silver and antimony) co-electrodeposition, various spatiotemporal patterns, which are similar to those in the reaction–diffusion system, are observed on the metal electrode surface. In our previous paper, we reported the phase diagram of several kinds of propagating stripe patterns as a function of constant current density, using an optical microscope. For several phases in the phase diagram, we discovered that the spatial bifurcation to two dynamic stripe patterns took place on the electrode surface at the initial stage of electrodeposition, and eventually, these two patterns transferred into one of the patterns in time. In this study, in order to compare the electric stability of such patterns, the potential time-evolution of each phase, in which the spatial bifurcation of patterns occurs, was investigated. From the experimental results, it was found that the patterns each have an inherent range or value of potential at which they are formed. However, the potential did not necessarily reach the value with low electric energy. Namely, this finding indicates that various other factors contribute to this phenomenon in addition to the electric stability.     

High-temperature oxidation process of intermetallic compound Ti-42 at% Al

The oxidation process of two-phase (Ti₃Al and TiAl) intermetallic compound, Ti-42 at% Al, in air at 1073 and 1273 K has been investigated. The oxidation at 1273 K is much faster than that at 1073 K; however, the oxidation kinetics are similar. During heating up, TiO₂ scale forms initially on the compound surface at about 973 K, and then Al₂O₃ scale forms at about 1273 K. For the isothermal heating, TiO₂ scale slowly grows up at 1073 K, while at 1273 K both TiO₂ and Al₂O₃ scales grow up drastically. The outer oxide scale consists of TiO₂ and the inner one consists of a mixture of TiO₂ and Al₂O₃. The volume of Al₂O₃, which forms after TiO₂ formation at the initial stage of oxidation, is larger at an area adjacent to the oxide-compound interface.