Relationship between electron sensitivity and chemical structures of polymers as EB resists: Poly(lactam thioether) as new positive EB resists

Poly(lactam thioether) was synthesized from tetrahydro-1,4-thiazepine-5(4H)-one by a ring opening reaction under various conditions and was evaluated as positive electron beam(EB) resist. It was found that poly(lactam thioether) was easily decomposed by EB irradiation. The decomposition by EB exposure may be attributed to cleavage of C? S bonds in the polymer chains. The sensitivity of poly(lactam thioether) was influenced by prebake temperature, molecular weight, and developer, a high sensitivity of 5.3 × 10^?6 coulomb/cm² was observed with a good resolution of less than 1 μm. Poly(lactam thioether) showed a high sensitivity and a high resolution, and is suitable as a positive EB resist.     

Electrochemical properties of 316L stainless steel with culturing L929 fibroblasts.

Potentiodynamic polarization and impedance tests were carried out on 316L stainless steel with culturing murine fibroblast L929 cells to elucidate the corrosion behaviour of 316L steel with L929 cells and to understand the electrochemical interface between 316L steel and cells, respectively. Potential step test was carried out on 316L steel with type I collagen coating and culturing L929 cells to compare the effects of collagen and L929 cells. The open-circuit potential of 316L steel slightly shifted in a negative manner and passive current density increased with cells, indicating a decrease in the protective ability of passive oxide film. The pitting potential decreased with cells, indicating a decrease in the pitting corrosion resistance. In addition, a decrease in diffusivity at the interface was indicated from the decrease in the cathodic current density and the increase in the diffusion resistance parameter in the impedance test. The anodic peak current in the potential step test decreased with cells and collagen. Consequently, the corrosion resistance of 316L steel decreases with L929 cells. In addition, collagen coating would provide an environment for anodic reaction similar to that with culturing cells.     

Levels and toxicokinetic behaviors of PCDD, PCDF, and coplanar PCB congeners in common cormorants from Lake Biwa, Japan

Concentrations of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and coplanar polychlorinated biphenyls (Co-PCBs) were determined in the liver and pectoral muscle of common cormorants (Phalacrocorax carbo) collected from Lake Biwa, Japan. To clarify the toxicokinetic behaviors and potential toxicities of these chemicals, the present study addresses life-stage- and tissue-specific accumulation of the congeners. Total 2,3,7,8-tetrachlorodibenzo-p-dioxin toxic equivalents (TEQs) were in the range of 360 to 50,000 pg/g lipid weight in the liver and 310 to 12,000 pg/g lipid weight in the pectoral muscle. Among congeners, for which toxic equivalency factors were assigned, PCB126, 2,3,4,7,8-P5CDF, and 1,2,3,7,8-P5CDD made a greater contribution to total TEQs in the liver. Hepatic concentrations of T4- to H6CDDs, P5- and H6CDFs, and Co-PCBs (except PCB77) significantly increased with growth of cormorants, leading to life-stage-related compositional changes. The concentration ratios of liver to pectoral muscle revealed preferential accumulation of higher chlorinated congeners in hepatic tissue. For most congeners, concentration ratios significantly increased with an increase in hepatic total TEQs, suggesting their concentration-dependent hepatic sequestration. These results imply the presence of hepatic binding protein(s) such as cytochrome P450, inducible by these chemicals, which mayfunction as a binding species different from aryl hydrocarbon receptor. On the basis of these results, we conclude that the toxicokinetic behavior of each congener is life-stage-, tissue-, and concentration-dependent. TEQs in wildlife populations exposed to multiple congeners with varying concentrations should be used with caution for risk assessment, even within a species.     

Direct Determination of the Stereoisomeric Composition of Callosobruchusic Acid,the Copulation Release Pheromone of the Azuki Bean Weevil, <Emphasis Type="Italic">Callosobruchus chinensis</Emphasis> L., by the 2D-Ohrui-Akasaka Method

The stereoisomeric composition of the copulation release pheromone of the azuki bean weevil, Callosobruchus chinensis L., was determined to be R:S = 3.3–3.4:1 by the 2D-Ohrui–Akasaka method.     

Antioxidative effects of sesamol and tocopherols at various concentrations in oils during microwave heating

The effectiveness of sesamol and tocopherols or their mixtures at different concentrations (50 to 800 ppm) on the oxidative stability of tocopherol‐stripped oils was studied under microwave heating conditions. Microwave heating accelerated the oxidation of the purified substrate oils. The oxidative deterioration of the oils was significantly (P<0.05) retarded during microwave heating by the addition of sesamol or tocopherols, and also mixtures of these antioxidants. A combination of sesamol and γ‐tocopherol was more efficient than that of sesamol and the other tocopherol homologues in inhibiting hydroperoxide formation in the oils. Useful levels of these antioxidants were 400 ppm for tocopherols and 50–400 ppm for sesamol. In general, the residual amount of sesamol in the oils during microwave heating was significantly greater (P<0.05) than that of tocopherols. Very effective combinations of tocopherols and sesamol as antioxidants for the purified oils were 200 or 400 ppm of γ‐tocopherol and 50, 200 or 400 ppm of sesamol, respectively. © 1999 Society of Chemical Industry     

Microwave roasting effects on the composition of tocopherols and acyl lipids within each structural part and section of a soya bean

Whole soya beans (Glycine max) were exposed to microwave roasting for 6, 12 or 20 min at a frequency of 2450 MHz. The seed coat, axis and sections of cotyledons separated from the three cultivars were analysed not only by high‐performance liquid chromatography for tocopherols but also by gas chromatography for fatty acids before and after microwave roasting. The tocopherols were predominantly detected in the axis, followed by the cotyledons and the seed coat, and the distribution patterns of tocopherol homologues for Mikawajima differed significantly (P < 0.05) from those for Okuhara or Tsurunoko. As many as 40% of the individual tocopherols originally present in the coat were lost at 12 min of roasting, whereas they were still retained to the extent of >80% in the cotyledons and the axis after 20 min of roasting. Significant decreases (P < 0.05) were observed not only in the amounts of triacylglycerols and phospholipids but also in the percentages of polyunsaturated fatty acids in the coat compared with those of the cotyledons or the axis. These results imply that microwave energy effected more significant differences (P < 0.05) in the distribution of tocopherols and acyl lipids in the coat than those of the cotyledons or the axis. © 1999 Society of Chemical Industry     

Effects of seed roasting temperature and time on the quality characteristics of sesame (Sesamum indicum) oil

The quality characteristics and composition of sesame oils prepared at different roasting temperatures (160–250°C) from sesame seeds using a domestic electric oven were evaluated as compared to an unroasted oil sample: only minor increases (P<0·05) in characteristics, such as peroxide value, carbonyl value, anisidine value and thiobarbituric acid reactive substances, of sesame oils occurred in relation to increasing roasting temperature and time between 160 and 200°C, but colour units of oils increased markedly over a 220°C roasting temperature. Significant decreases (P<0·05) were observed in the amounts of triacylglycerols and phospholipids in the oils prepared using a 250°C roasting temperature. The amounts of γ-tocopherol and sesamin still remained over 80 and 90%, respectively, of the original levels after roasting at 250°C. In the oil prepared using a 250°C roasting temperature, sesamol was detected at 3370 mg per kg oil, but sesamolin was almost depleted after 25 min of roasting. Burning and bitter tastes were found in the oils prepared at roasting temperatures over 220°C. The results suggested that a high-quality product would be obtained by roasting for 25 min at 160 or 180°C, 15 min at 200°C and 5 min at 220°C when compared with the other samples. © 1997 SCI.     

Formation of Novel ZSM-5/Porous Mullite Composite from Sintered Kaolin Honeycomb by Hydrothermal Reaction

The formation and properties of continuous ZSM-5 film on a porous mullite honeycomb have been investigated. The porous mullite honeycomb coated with ZSM-5 film provides a novel microporous (0.5 nm in diameter)–macroporous (0.5–0.6 μm in diameter) composite. Amorphous silica-glass in the kaolin honeycomb sintered at 1650°C is used as a source for ZSM-5 formation. The honeycomb is hydrothermally treated in NaOH, tetrapropylammonium bromide, and water to prepare a novel honeycomb–zeolite composite by in situ crystallization of ZSM-5 film. This paper describes the effects of hydrothermal conditions—such as reaction temperature, time, and concentration of NaOH solution—on the formation of ZSM-5 film on the honeycomb, and on the mechanical strength and porous properties of the honeycomb composite.     

Photocatalytic behavior of TiO2 nanoparticles supported on porous aluminosilicate surface modified by cationic surfactant

In order to utilize the photocatalytic function of TiO₂ nanoparticles in materials manufactured from organic polymeric compounds, such as paper, resins, and textiles, TiO₂ nanoparticles supported on aluminosilicate, which contained 1, 5, and 10 wt% of TiO₂ were prepared by mixing commercial TiO₂ nanoparticles and porous aluminosilicate at pH 7 in a cationic surfactant aqueous solution. Most of the supported TiO₂ nanoparticles on the aluminosilicate surface were observed by TEM–EDS (energy depressive X-ray spectroscopy) analysis. TiO₂ nanoparticles supported on aluminosilicate reduced the formaldehyde concentration from 20 to 0 ppm after UV irradiation for 20 h; the reduction of formaldehyde concentration under UV irradiation was obviously different from that in the dark. Moreover, a paper mixed with 20 wt% of TiO₂ nanoparticles supported on aluminosilicate bleached the stains colored with cigarette tar after UV irradiation for 6 h. However, the paper maintained its initial tensile strength even after UV irradiation for 1 year; in contrast, the paper mixed with a simple dry mixture of TiO₂ powder and aluminosilicate lost approximately half of its initial tensile strength after a year. TiO₂ nanoparticles supported on aluminosilicate could exhibit photocatalytic activity without decomposing the organic polymeric compounds.