Effect of tensile strain rate on the mechanical properties of constrained-uniaxially and simultaneous-biaxially drawn poly(ethylene terephthalate) sheets

The dependency of the mechanical properties (Young's modulus, yield strength, breaking strain, and breaking energy) of preoriented poly(ethylene terephthalate) (PET) sheets on the tensile deformation speeds was examined and discussed in relation to changes of density and birefringence. The procedures for preorientation were constrained-uniaxially (CU) and simultaneous-biaxially (SB) drawings at 65°C. The performance characteristics of the present tensile testing at room temperature were obtained over a wide range of extension rates (1.7 × 10^?4?13.1 m/s = 0.29–2.3 × 10⁴%/s) without changing the mode of deformation and the shape of the test pieces. The CU drawn PET is strain-rate-independent and mechanically superior in structure in the preextended direction with draw ratio λ > 2.5. In the SB drawn PET such a structure comes into existence at λ > 3, which has, furthermore, no dependency on draw direction (mechanically isotropic). The draw ratio of the latter case corresponded to the birefringence (?Δn/d) of about 5 × 10^?2. These results imply a possibility of producing the strain rate (from low to impact speeds) independent, anisotropy-free, and mechanically superior molded products of PET if adequate extrusion or blow molding methods which induce multiaxial orientation with ?Δn/d > 5 × 10^?2 are developed.     

Kinetic process of phase separation in Co-SiO2 thin films and preparation of mesoporous SiO2 thin films with mesopore channels aligned perpendicularly to substrate surfaces

A physical co-sputter deposition process under a relevant working gas pressure condition was used to produce a multi-component thin film with a longitudinally self-organized microstructure. In this paper, Co-Si-O thin films were prepared by radio frequency (RF) magnetron sputtering, and their growth structures were studied by means of SEM, TEM, XRD and XPS. The microstructural changes in the Co-Si-O thin film and their dependence on Ar working gas pressure were investigated; the formation of Co-Si-O thin films, having a regular array of needle-like Co columns aligned perpendicularly to the substrate surfaces, was observed with appropriate Ar working gas pressure, and the diameter of the columns increased with increasing Ar pressure. Mesoporous silica thin films having perpendicular mesopore channels were obtained by chemical etching of the columnar Co parts in the Co-Si-O thin films. Through experimental observations, we propose that the phase separation and resultant microstructures in the thin films are determined by the surface mobility of the two components (Co and silica) on the film surface. A simple model, incorporating a diffusion process in the simultaneous deposition of two components, is presented. The model demonstrates the general trends of a kinetically self-organized microstructure in a two-component thin film.     

Chemical kinetic modeling of ammonia oxidation with improved reaction mechanism for ammonia/air and ammonia/hydrogen/air combustion

To achieve comprehensive prediction of ammonia combustion in terms of flame speed and ignition delay time, an improved mechanism of ammonia oxidation was proposed in this work. The present model (UT-LCS) was based on a previous work [Song et al., 2016] and improved by relevant elementary reactions including NH₂, HNO, and N₂H₂. The model clearly explained reported values of laminar flame speed and ignition delay time in wide ranges of equivalence ratio and pressure. This suggests that NH₂, HNO, and N₂H₂ reactivities play a key role to improve the reaction mechanism of ammonia oxidation in the present model. The model was also applied to demonstrate NH₃/H₂/air combustion. The present model also appropriately predicted the laminar flame speed of NH₃/H₂/air combustion as a function of equivalence ratio. Using the model, we discussed the reduction of NO concentration downstream and H₂ formation via NH₃ decomposition in NH₃/H₂ fuel-rich combustion. The results provide suggestions for effective combustion of NH₃ for future applications.     

Histidine-Rich Glycoprotein Suppresses the S100A8/A9-Mediated Organotropic Metastasis of Melanoma Cells

The dissection of the complex multistep process of metastasis exposes vulnerabilities that could be exploited to prevent metastasis. To search for possible factors that favor metastatic outgrowth, we have been focusing on secretory S100A8/A9. A heterodimer complex of the S100A8 and S100A9 proteins, S100A8/A9 functions as a strong chemoattractant, growth factor, and immune suppressor, both promoting the cancer milieu at the cancer-onset site and cultivating remote, premetastatic cancer sites. We previously reported that melanoma cells show lung-tropic metastasis owing to the abundant expression of S100A8/A9 in the lung. In the present study, we addressed the question of why melanoma cells are not metastasized into the brain at significant levels in mice despite the marked induction of S100A8/A9 in the brain. We discovered the presence of plasma histidine-rich glycoprotein (HRG), a brain-metastasis suppression factor against S100A8/A9. Using S100A8/A9 as an affinity ligand, we searched for and purified the binding plasma proteins of S100A8/A9 and identified HRG as the major protein on mass spectrometric analysis. HRG prevents the binding of S100A8/A9 to the B16-BL6 melanoma cell surface via the formation of the S100A8/A9 complex. HRG also inhibited the S100A8/A9-induced migration and invasion of A375 melanoma cells. When we knocked down HRG in mice bearing skin melanoma, metastasis to both the brain and lungs was significantly enhanced. The clinical examination of plasma S100A8/A9 and HRG levels showed that lung cancer patients with brain metastasis had higher S100A8/A9 and lower HRG levels than nonmetastatic patients. These results suggest that the plasma protein HRG strongly protects the brain and lungs from the threat of melanoma metastasis.     

Survey on the quality of commercial Nigari (crude magnesium chloride [sea water])

Contents of minerals (Mg, Ca, Na and K), anions (SO4(2-), Br- and Cl) and heavy metals (Pb, Cd, Zn, Hg and As) were determined in 17 commercial samples of Nigari, 15 samples of crude magnesium chloride (sea water) products as a food additive and 2 magnesium-containing foods. Obtained values were compared with the specifications proposed in a draft of the eighth edition of Japan's Specifications and Standards for Food Additives. Out of 15 food additive samples, only 5 samples satisfied the specification. Since the Joint FAO/WHO Expert Committee on Food Additives (JECFA) proposed to lower the limits of heavy metals in food additives, a simple method was developed for the determination of low levels of Pb and Cd by extracting chelates of these metals with organic solvents. The quantification limits for Pb and Cd were 0.5 microg/g and 0.05 microg/g, respectively. It was estimated from the SO4(2-)/Ca ratios that 15 samples were sea water evaporation products, and the remaining 2 were ion-exchange membrane process products. No pollution with heavy metals was found in any of the samples.