Phase morphologies and mechanical properties of high‐impact polystyrene (HIPS) and polycarbonate blends compatibilized with polystyrene and polyarylate block copolymer

Phasemorphology and mechanical properties of blends of high‐impact polystyrene (HIPS) and polycarbonate (PC) blends compatibilized with a polystyrene (PS) and polyarylate (PAr) (PS–PAr) block copolymer were investigated. Over a broad range of composition from 50/50 through 30/70, HIPS/PC blends formed cocontinuous structures induced by the flow during the extrusion or injection‐molding processes. These cocontinuous phases had heterogeneity between the parallel and perpendicular directions to the flow. The micromorphology in the parallel direction to the flow consisted of stringlike phases, which were highly elongated along the flow. Their longitudinal size was long enough to be longer than 180 μm, while their lateral size was shorter than 5 μm, whereas that in the perpendicular direction to the flow showed a cocontinuous phase with regular spacing due to interconnection or blanching among the stringlike phases. The PS–PAr block copolymer was found to successfully compatibilize the HIPS/PC blends. The lateral size of the stringlike phases could be controlled both by the amount of the PS–PAr block copolymer added and by the shear rate during the extrusion or injection‐molding process without changing their longitudinal size. The HIPS/PC blend compatibilized with 3 wt % of the PS–PAr block copolymer under an average shear rate of 675 s^?1 showed a stringlike phase whose lateral size was reduced almost equal to the rubber particle size in HIPS. The tensile modulus and yield stress of the HIPS/PC blends could be explained by the addition rule of each component, while the elongation at break was almost equal to that of PC. These mechanical properties of the HIPS/PC blends can be explained by a parallel connection model independent of the HIPS and PC phases. On the other hand, the toughness factor of the HIPS/PC blends strongly depended on the lateral size of the stringlike phases and the rubber particle size in the HIPS. It was found that the size of the string phases and the rubber particle should be smaller than 1.0 μm to attain a reasonable energy absorbency by blending HIPS and PC. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 2347–2360, 2001     

Direct Injection of CRISPR/Cas9-Related mRNA into Cytoplasm of Parthenogenetically Activated Porcine Oocytes Causes Frequent Mosaicism for Indel Mutations

Some reports demonstrated successful genome editing in pigs by one-step zygote microinjection of mRNA of CRISPR/Cas9-related components. Given the relatively long gestation periods and the high cost of housing, the establishment of a single blastocyst-based assay for rapid optimization of the above system is required. As a proof-of-concept, we attempted to disrupt a gene (GGTA1) encoding the α-1,3-galactosyltransferase that synthesizes the α-Gal epitope using parthenogenetically activated porcine oocytes. The lack of α-Gal epitope expression can be monitored by staining with fluorescently labeled isolectin BS-I-B₄ (IB4), which binds specifically to the α-Gal epitope. When oocytes were injected with guide RNA specific to GGTA1 together with enhanced green fluorescent protein (EGFP) and human Cas9 mRNAs, 65% (24/37) of the developing blastocysts exhibited green fluorescence, although almost all (96%, 23/24) showed a mosaic fluorescent pattern. Staining with IB4 revealed that the green fluorescent area often had a reduced binding activity to IB4. Of the 16 samples tested, six (five fluorescent and one non-fluorescent blastocysts) had indel mutations, suggesting a correlation between EGFP expression and mutation induction. Furthermore, it is suggested that zygote microinjection of mRNAs might lead to the production of piglets with cells harboring various mutation types.     

Novel vitamin E derivative with 4-substituted resorcinol moiety has both antioxidant and tyrosinase inhibitory properties

A novel vitamin E derivative, (6″-hydroxy-2″,5″,7″,8″-tetramethylchroman-2″-yl) methyl 3-(2′,4′-dihydroxyphenyl)propionate (TM4R), which has a chromanoxyl ring and 4-substituted resorcinol moieties, was synthesized; and its inhibitory effects on tyrosinase, antioxidant ability, and lightening effect of ultraviolet B (UVB)-induced hyperpigmentation were estimated. TM4R showed potent inhibitory activity on tyrosinase, which is the rate-limiting enzyme in melanogenesis. The scavenging activities of TM4R on 1,1-diphenyl-2-picrylhydrazyl and hydroxyl radicals were found to be nearly the same as those of α-tocopherol. Furthermore, an efficient lightening effect was observed following topical application of TM4R to UVB-stimulated hyperpigmented dorsal skin of brownish guinea pigs. These results suggest that TM4R may be a candidate for an efficient whitening agent, possibly by inhibiting tyrosinase activity and biological reactions caused by reactive oxygen species.     

Grafting vinyl monomers onto silk (Bombyx mori) using different initiators: Properties of grafted silk

The graft–copolymerization of silk with methacrylamide (MAA), 2‐hydroxyethyl methacrylate (HEMA), and methyl methacrylate (MMA) was studied using three different free‐radical initiators: an inorganic peroxide [ammonium persulfate (APS)] and two azo compounds [2,2′‐azobisisobutyronitrile (AIBN) and 2,2′‐azobis(2‐methylpropionamidine) dihydrochloride (ADC)]. The rate and yield of grafting followed the order: APS > AIBN > ADC. The performance of AIBN was close to that of APS in terms of weight gain attained. The degree of yellowing of grafted silk varied as a function of the initiator–monomer system used. APS induced the highest degree of yellowing, regardless of which monomer was used, whereas silk grafted with the MAA/AIBN system displayed the lowest level of yellowing. Moisture regain of grafted silk changed as a function of the hydrophilic/hydrophobic character of the grafted polymer, regardless of the kind of initiator used. Accordingly, tensile properties showed a tendency to decrease with increasing weight gain of grafted silk, the extent of which was independent of the kind of monomer and initiator used. The different initiators did not induce any appreciable change in the fine structure of silk, as demonstrated by optical measurements. Uneven surface deposition of homopolymer was detected to variable extent with MMA and HEMA grafting, whereas the surface of MAA‐grafted silk was completely free of any foreign deposit, independently of the initiator used. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 1401–1409, 2001     

Low-Temperature Electrochemical Synthesis of ZrO2 Films on Zirconium Substrates: Deposition of Thick Amorphous Films and in situ Crystallization on Zirconium Anode

The feasibility of synthesizing crystalline ZrO₂ films at low temperatures was evaluated using an electrochemical method. Anodization of zirconium-metal substrates in tetraethyl ammonium hydroxide (TEAOH) solutions under constant applied voltage conditions at ∼25° and ∼100°C was investigated. The chemistry and microstructure of the anodic oxide films deposited on the zirconium-metal substrates under the above conditions were characterized using X-ray diffractometry and scanning electron microscopy. The results indicated that, with sufficiently high applied voltages (in the range of 300 V) at pH ∼9.5, the initial dissolution of the zirconium anode resulted in the local saturation of the electrolyte solution with Zr⁴⁺, forming Zr(OH)⁻₅, which deposited electrophoretically on the anode as a thick, gelatinous film at 25°C. Similar treatments at 100°C resulted in an in situ crystallization of Zr(OH)₄ gel to monoclinic ZrO₂.     

Interfacial Reactions between Sapphire and Silver—Copper—Titanium Thin Film Filler Metal

Wetting and brazing studies of sputtering-deposited, submicrometer thin film filler metal in an Ag—Cu—Ti/Al₂O₃ system were performed. The interfacial reaction layer between the filler metal and Al₂O₃ was investigated. It is possible to make a brazing joint even with a reaction layer of less than 100 nm thickness. Different types of interfacial reaction layers were observed when the Ti content in the filler metal was varied. The Cu—Ti—O system compounds were observed in the samples with high wetting capabilities, but not in the sample with low wetting characteristics. It was found that these compounds are substances that promote effective brazing.     

Production of antimicrobially active silk proteins by use of metal‐containing dyestuffs

The work presented here discusses a new technique for preparing silk fibers and films with persistent antimicrobial activity through use of metallic dyestuffs during the fiber dyeing process. The length of the silk fibers investigated contracted when the fibers were immersed in concentrated neutral salt solutions, such as calcium or potassium nitrate, at elevated temperature levels. The birefringence and molecular orientation of the silk fibroin molecules became less ordered by the action of the neutral salt solutions, resulting in increased dyestuff absorption. Subsequently, contracted silk fibers were dyed with metallic dyestuffs containing Cr or Cu for the purpose of obtaining silk fibers with antimicrobial activity. Silk fibers dyed with metallic dyestuffs showed significant antimicrobial activity against the plant pathogen Cornebacterium and the human pathogen Coli bacillus. Tensile strength of the silk fibers after the salt shrinking and dyeing processes did not show a significant change, whereas the elongation at break was increased slightly. The techniques described here for preparing significantly active antimicrobial silk fibers are effective and economic ways of providing new materials for industrial and biomedical applications. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 1181–1188, 2002     

Color control of Japanese soy sauce (shoyu) using membrane technology

The present study systemically decolorized soy sauce using a membrane process to analyze the separation mechanism. An ultrafiltration (UF) membrane (NTU-2120) exhibited only slight decolorization ability. A nanofiltration (NF) membrane with a lower molecular weight cut-off and produced by sulfonated polysulfone (NTR-7400 series) rather than polyvinyl alcohol/polyamide (NTR-7250) had higher decolorization ability. The NF membranes rejected total nitrogen by 17–24%, unsalted soluble solid content by 24–32%, reducing sugar by 25–43%, and amino acids by 10–25%. The NTR-7400 series membrane rejected lactic acid by 6–9%, and pyroglutamic acid by 11–21%; other quality indexes were maintained. In the NF membrane processes, higher rejection of acidic amino acids than neutral and base amino acids was observed. The separation performance was governed by the electrical effect as well as the sieve effect. Soy sauce color could be controlled by blending NF membrane-processed soy sauce with feed soy sauce. Color can be matched to preference in accordance with dishes by suitably blending NF membrane-processed soy sauce with feed soy sauce.     

Optical Active Nano-Glass-Ceramics

This paper reviews the synthesis and characterization of several transparent glass-ceramics with optical active nanocrystals. Glass-ceramics containing ferroelectric Sr_xBa_1-xNb₂O₆ nanocrystals with an ellipsoidal shape show optical phase modulations in the presence of alternative electric fields. In the glass-ceramics with Ba₂TiSi₂O₈ (BTS) nanocrystals, BTS crystalline layers with a thickness of approximately 120 nm are formed at the surface and ellipsoidal-shaped crystallites with a diameter of 100–200 nm are dispersed in the glass matrix. Some TeO₂-based and GeO₂-based glasses show a prominent nanocrystallization. RE-doped CaF₂ nanocrystals are patterned in a spatially selected region by laser irradiations. The size, morphology, and dispersion state of nanocrystals should be carefully checked in each glass system and composition. The basic concept for the design of glass system and composition is also discussed. Some data on optical active performances in transparent glass-ceramics with nanocrystals were introduced.     

Crystalline Phases and YAG Laser-Induced Crystallization in Sm2O3–Bi2O3–B2O3 Glasses

The glass formation region, crystalline phases, second harmonic (SH) generation, and Nd:yttrium aluminum garnet (YAG) laser-induced crystallization in the Sm₂O₃–Bi₂O₃–B₂O₃ system were clarified. The crystalline phases of Bi₄B₂O₉, Bi₃B₅O₁₂, BiBO₃, Sm _x Bi_{1− x} BO₃, and SmB₃O₆ were formed through the usual crystallization in an electric furnace. The crystallized glasses consisting of BiBO₃ and Sm _x Bi_{1− x} BO₃ showed SH generations. The formation of the nonlinear optical BiB₃O₆ phase was not confirmed. The formation (writing) region of crystal lines consisting of Sm _x Bi_{1− x} BO₃ by YAG laser irradiation was determined, in which Sm₂O₃ contents were∼10 mol%. The present study demonstrates that Sm₂O₃–Bi₂O₃–B₂O₃ glasses are promising materials for optical functional applications.