Surface Modification of Epoxy Resin with Silicone-containing Block Copolymers

In order to improve oil and water repellency, silicone-containing block copolymers, composed of methylmethacrylate (MMA), glycidylmethacrylate (GMA), and polydimethylsiloxanemethacrylate (SMA), were blended in an epoxy resin. It was expected that the low surface energy dimethylsiloxane segments would adsorb and orient at the exterior of the resin to make a thin surface phase and the glycidyl groups would mesh with the epoxy resin by primary bonding. The techniques of X-ray photoelectron spectroscopy (ESCA), dynamic contact angle (DCA) and peel strength measurements of pressure sensitive adhesives were used to characterize the modified epoxy resin surface phases. The amount of Si_2p obtained via angular dependent ESCA investigation in the near surface region of the modified resin increased with decreasing sampling depth. With an increase in modifier content, both the amount of Si_2p and O_1s also increased. Both advancing and receding contact angles for an aluminum plate coated with modified resin, measured by dipping into and out of water, increased with the addition of these modifiers. The peel strength of a pressure sensitive adhesive tape affixed to the modified epoxy resin decreased dramatically with increasing modifier content. It was found that these copolymers were good surface modifiers to improve oil and water repellency and that they acted as release agents.     

A temperature-insensitive erbium-doped fiber amplifier for terrestrial wavelength-division-multiplexing systems

We have evaluated a variation in the temperature dependence of an erbium-doped fiber gain spectrum by a pump wavelength in the 980-nm band for the first time. By optimizing both the pump wavelength in the 980-nm band and a temperature-sensitive gain flattening filter, the gain change of an erbium-doped fiber amplifier was successfully suppressed to 0.18 dB/sub pp/ in the temperature range between 0/spl deg/C and 65/spl deg/C and the wavelength range of 37.0 nm.     

The Tensile Properties of an Fe-4 Pct Mo-0.2 Pct C Martensite Tempered under Applied Stress

In Fe-4 pct Mo-0.2 pct C martensite which is a typical secondary hardening steel, premature failure occurred in tensile test at 600 °C to 700 °C where solute atoms could diffuse easily. To clarify this phenomenon, the quenched specimens were tempered under applied stress and tensile-tested at room temperature. The following results were obtained: (1) Typical intergranular fracture was observed in specimens tempered in a temperature range of 600 °C to 650 °C with tempering times of five minutes to 10 minutes and applied stress (70 MPa to 140 MPa). (2) Based on Auger analysis, this phenomenon was considered to be caused by segregation of P, S, and Mo on prior austenite grain boundaries due to applied stress. (3) The direction of applied stress was found to be very significant. Namely, when the tensile direction was parallel to the applied stress during tempering, the specimen was more brittle, and when tensile direction was normal to the applied stress, the specimen was not so brittle. (4) To reduce this embrittlement, solution treatment temperature was adjusted, and it was found that the embrittlement was considerably reduced both in specimens with fine prior austenite grains and with some ferrite phase on prior austenite grain boundaries. Formerly with Kyoto University Formerly with Kyoto University This paper is based on a presentation made at the “Peter G. Winchell Symposium on Tempering of Steel” held at the Louisville Meeting of The Metallurgical Society of AIME, October 12-13, 1981, under the sponsorship of the TMS-AIME Ferrous Metallurgy and Heat Treatment Committees.     

Involvement of follicular basement membrane and vascular endothelium in blood follicle barrier formation of mice revealed by 'in vivo cryotechnique'

The molecular sieve with size- and charge selectivity in ovarian follicles, the so-called blood-follicle barrier (BFB), was examined during follicular development under physiological conditions to reveal ovarian structures responsible for the BFB by using our 'in vivo cryotechnique' (IVCT). Mouse ovary specimens were prepared with different methods including IVCT, immersion, or perfusion chemical fixation and quick-freezing following resection or perfusion. Their paraffin sections or cryosections were stained with hematoxylin-eosin or immunostained for serum proteins with different molecular weights: albumin, immunoglobulin (Ig) G1 heavy chain, inter-alpha-trypsin inhibitor (I alpha I), fibrinogen, and IgM. Their immunoreactivity was better preserved with IVCT. The immunostaining for albumin was clearly observed in blood vessels, interstitium, and developing follicles, but that of IgG1, I alpha I, or fibrinogen was significantly decreased inside the follicles. IgM was immunohistochemically decreased throughout the interstitium outside blood vessels. The immunoreactivities of IgG1 and IgM, as compared with albumin, were clearly changed along follicular basement membranes and around vascular endothelial cells respectively. These findings indicate that BFB functions throughout follicular development, and the follicular basement membrane and the vascular endothelium could play some significant roles in the permselectivity for such soluble proteins with intermediate and high molecular weight respectively.     

Application of electron holography to the determination of contact potential difference in an AlGaN/AlN/Si heterostructure

Electron holography was applied to determine the contact potential differences in an AlGaN/AlN/Si heterostructure formed by metallorganic vapor phase epitaxy. Since mean inner potentials are generally different for different materials, their values before and after forming the junction were evaluated first, then the contact potential difference was obtained by subtracting the difference of the mean inner potentials before forming the junction from the corresponding difference after forming the junction. The contact potential differences thus obtained were consistent with a reported asymmetric nonlinear behavior in the current-voltage characteristics measured for a similar heterojunction diode.     

Bioelectrochemical regulation accelerates facultatively syntrophic proteolysis

Bioelectrochemical systems can affect microbial metabolism by controlling the redox potential. We constructed bioelectrochemical cultures of the proteolytic bacterium, Coprothermobacter proteolyticus strain CT-1, both as a single-culture and as a co-culture with the hydrogenotrophic methanogen, Methanothermobacter thermautotrophicus strain ?H, to investigate the influences of bioelectrochemical regulation on facultatively syntrophic proteolysis. The co-culture and single-culture were cultivated at 55°C with an anaerobic medium containing casein as the carbon source. The working electrode potential of the bioelectrochemical system was controlled at -0.8V (vs. Ag/AgCl) for bioelectrochemical cultures and was not controlled for non-bioelectrochemical cultures. The cell densities of hydrogenotrophic methanogen and methane production in the bioelectrochemical co-culture were 3.6 and 1.5 times higher than those in the non-bioelectrochemical co-culture after 7 days of cultivation, respectively. Contrastingly, the cell density of Coprothermobacter sp. in the bioelectrochemical co-culture was only 1.3 times higher than that in the non-bioelectrochemical co-culture. The protein decomposition rates were nearly proportional to the cell density of Coprothermobacter sp. in the all types of cultures. These results indicate that bioelectrochemical regulation, particularly, affected the carbon fixation of the hydrogenotrophic methanogen and that facultatively syntrophic proteolysis was accelerated as a result of hydrogen consumption by the methanogens growing well in bioelectrochemical co-cultures.     

Comparative study of large-scale hydrogen storage technologies: Is hydrate-based storage at advantage over existing technologies?

Different technologies possibly applicable for large-scale hydrogen storage in urban or industrial-complex areas have been comparatively evaluated, focusing on the facility-construction costs, the utility expense, and the ground area required for the facility for each technology. The specific technologies examined in this study are the storage in the form of compressed or liquefied gas, the storage using a metal hydride, and the storage using a clathrate hydrate. The common requirements for these technologies are the function of loading or unloading hydrogen gas at a rate up to 3000 Nm³/h and also the storage capacity of 6.48 × 10⁶ Nm³ that enables continuous 90-day loading or unloading at the rate of 3000 Nm³/h. The storage using a clathrate hydrate is found to require the minimum ground area and, if the cool energy necessary for hydrate production is available from adjacent LNG facilities, the minimum annual depreciation + utility expense.     

Process intensification of continuous starch hydrolysis with a Couette–Taylor flow reactor

Starch gelatinization and enzymatic hydrolysis was carried out in a continuous Couette–Taylor flow reactor with a water jacket. The degree of gelatinization and the concentration of reducing sugars produced via enzymatic saccharification were evaluated by varying operational variables: rotation speed of an inner cylinder, initial concentration of starch and reaction temperature. At the initial concentration of the starch suspension, 50 kg m⁻³, starch saccharification proceeded sufficiently even at low rotation speed of the inner cylinder and saccharification temperature. At the higher initial concentration, 100 and 150 kg m⁻³, a higher rotation speed of the inner cylinder and temperature of the saccharification section were required to obtain sufficient starch saccharification. Even in the case of C₀ = 100 and 150 kg m⁻³, the more reducing sugar was obtained by choosing an adequate rotation speed of the inner cylinder and a reaction temperature.     

Stress resistance of biofilm and planktonic Lactobacillus plantarum subsp. plantarum JCM 1149

The purpose of this study was to investigate the change in resistance of biofilm and planktonic food spoilage lactic acid bacteria (LAB) to environmental stresses, which strongly inhibit bacterial growth and are important in food preservation or in disinfection. The stress responses of biofilm and planktonic cells of Lactobacillus plantarum subsp. plantarum JCM 1149, which was used as a model spoilage bacterium, in various organic acids (namely, acetic acid, citric acid, lactic acid, and malic acid), ethanol, and sodium hypochlorite, were investigated using survival tests. The bacterial cells in biofilms showed greater resistance to all treatments than the planktonic bacterial cells in either the stationary or logarithmic phase. The planktonic bacterial cells showed reduced resistance to acetic acid after the cell suspension was diluted; however, intriguingly, the bacterial cells in biofilms maintained their resistance to acetic acid even after they were suspended or the cell suspension was diluted. These findings suggested the risk for food spoilage due to LAB derived from biofilms and suspended or diluted in foods, and demonstrated the importance of controlling biofilms of LAB in the food industry.     

Clinical evaluation of fullerene-C60 dissolved in squalane for anti-wrinkle cosmetics

Highly purified and organic solvent-free fullerene-C60 was dissolved, at nearly saturated concentration of 278 ppm, in squalane prepared from olive oil, which is designated as LipoFullerene (LF-SQ) and was examined for usage as a cosmetic ingredient with antioxidant ability. The aim of this study was to assess the anti-wrinkle formation efficacy of LF-SQ in subjects. A total of 23 Japanese women (group I: age 38.9 +/- 3.8, n = 11, group II; age 39.4 +/- 4.3, n = 12) were enrolled in an 8-week trial of LF-SQ blended cream in a randomized, matched pair double-blind study. The LF-SQ cream was applied twice daily on the right or left half of the face, and squalane blended cream (without fullerene-C60) was applied as the placebo on another half of the face. As clinical evaluations of wrinkle grades, visual observation and photographs, and silicone replicas of both crow's feet areas were taken at baseline (0 week) and at 4th and 8th weeks. Skin replicas were analyzed using an optical profilometry technique. The wrinkle and skin-surface roughness features were calculated and statistically analyzed. Subsequently, trans-epidermal water loss (TEWL), moisture levels of the stratum corneum, and visco-elasticity (suppleness: RO and elasticity: R7) were measured on cheeks by instrumental analysis. LF-SQ cream enhanced the skin moisture and the anti-wrinkle formation. LF-SQ cream that was applied on a face twice daily was not effective at 4th week, but significantly more effective than the placebo at 8th week (p < 0.05) without severe side effects. The roughness-area ratio showed significant improvement (p < 0.05) at 8th week with LF-SQ cream as compared to 0 week with LF-SQ cream, but no significant difference was detected between LF-SQ cream and the placebo. We suggest that LF-SQ could be used as an active ingredient for wrinkle-care cosmetics.