Creep behavior of glass‐fiber‐reinforced nylon 6 products

The creep properties, that is, the velocity constant, activation energy, stress index, and time index, of a test piece (TP) cut from a glass‐fiber‐reinforced nylon 6 product were successfully determined by a compression creep test. In the determination of the creep properties, the experimental creep curves for the TP were fitted by finite element analysis (FEA). Fiber‐reinforced nylon 6 beams with different fiber orientations were also prepared, and their creep properties were successfully determined by a combination of the bending creep test and the corresponding analysis. The creep behavior of the press‐fit component composed of a metal collar and a fiber‐reinforced nylon 6 product was predicted by FEA with the determined creep properties of the TP. The predicted retention forces were in good agreement with the experimental ones. The effects of the fiber orientation on the long‐term reliability of the press‐fit component are also discussed. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Polymerization of vinyl chloride with Cp*Ti(OPh)3/MAO catalyst in toluene

Polymerization of vinyl chloride (VC) with a Cp*Ti(OPh)₃/MAO catalyst in toluene was investigated. The polymerization rate was lower than that in CH₂Cl₂, and the mm triad concentration of the PVC obtained in toluene was somewhat higher than that of the PVC obtained in CH₂Cl₂. As the polymerization in toluene proceeded at a considerable rate, a kinetic study of this polymerization was undertaken. The polymer yield increased with reaction time, and the molecular weight of the polymer increased with increasing polymer yield. The M_w/M_n ratio of the polymer decreased with increasing polymerization temperature. The initiator efficiency of the catalyst was low at the initial stage of the polymerization in toluene, but it reached nearly 100% when the polymerization was carried out for more than 30 h. The control of both themolecular weight of PVC and its main‐chain structure was found to be possible in the polymerization of VC with the Cp*Ti(OPh)₃/MAO catalyst in toluene. J. VINYL ADDIT. TECHNOL., 2009. © 2009 Society of Plastics Engineers     

Toward elucidating the full spectrum of mite allergens--state of the art

Our research has focused on the molecular design of immunotherapeutic vaccines and the advancement of mite-allergy diagnosis. Here, we describe the research history of the major group 1 and group 2 allergens, immunoelectrophoretic analyses covering the complete spectrum of mite allergens, our results on allergens with distinctive characteristics (a conjunctival congestion-eliciting antigen [LM2], an immunotherapeutic antigen [HM2] with high efficacy and without definite adverse reactions, and a potent T-cell stimulatory antigen [HM1] with secretion of IFN-gamma), the full spectrum and immunochemical properties of the major and other important mite allergens (including our newly described allergens: a pan-allergen [tropomyosin, group 10], a potent T-cell stimulatory allergen [M-177, apolipophorin, group 14] and its peptide fragments Mag1 and Mag3, a moderate IgE-binding allergen [gelsolin/villin, group 16], an EF-hand Ca2+-binding allergen [group 17], and a less IgE-binding allergen [heat shock protein 70]), and prospects for the development of immunotherapeutic and diagnostic agents.     

Molecular design of hole transport material with various ionizationpotential for organic light-emitting diode applications

In this paper, we examine the effects of the properties for hole transport materials (HTM's) on the performance of organic light-emitting diodes (OLED's). The ionization potentials (I_p) of the HTM's could be estimated by the Hammett constant of the substituent. We have synthesized a series of HTM's with various I_p's, which are called FTPD's. The FTFD's have high glass transition temperature above 80°C, because of their fluorene structure. We fabricated double-layer OLED's with the FTPD's. The I_p's of the FTPD's affected the driving voltage, although they did not affect the quantum efficiency     

Root hair abundant genes LjRH101 and LjRH102 encode peroxidase and xyloglucan endotransglycosylase in Lotus japonicus

We have identified root hair abundant genes, LjRH101 and LjRH102, from a model legume Lotus japonicus by cDNA-amplified fragment length polymorphism (AFLP). These two genes will be suitable markers for the molecular biological identification of root hairs.     

Process design of chondrocyte cultures with monolayer growth for cell expansion and subsequent three-dimensional growth for production of cultured cartilage

The subculture of rabbit chondrocytes with serial passaging was carried out for cell expansion on a collagen-coated surface, and the morphological transition of round-shaped cells to spindle-shaped ones was examined. The observation of cytoskeletal formation by staining F-actin and vinculin supported the view that the round-shaped cells were in the process of differentiation with immature stress fibers relating to less cellular polarity. The cellular morphology was estimated in terms of the distribution of roundness, R(C), during the subculturing on the collagen substrate. The frequency of the number of round-shaped cells, which was defined as the ratio of the number of cells with R(C) >0.9 against the total cell number, was correlated in a logarithmic formula with the number of population doublings during the subcultures. Kinetic models were adopted for the process design of the combined culture of chondrocytes with monolayer growth on the collagen substrate and subsequent three-dimensional growth in Atelocollagen gel, employing the boundary conditions based on the population balance between differentiated and dedifferentiated cells. The combined culture was performed successfully according to the process design scheduled as monolayer growth for 240 h and three-dimensional growth for 264 h, the number of seed cells being 68% of that in the conventional culture for 504 h where monolayer growth for cell expansion was not included.     

Conductance stopped-flow study of cationic polymerizations of p-methoxystyrene and styrene

Summary Conductance stopped-flow analysis on the initial phase of cationic polymerizations of p-methoxystyrene and styrene revealed rapid changes in conductance (within 20–50 ms) that were related to the initiation process. Initiation rate constants were obtained for CF₃SO₃H, CH₃COClO₄, and BF₃O (C₂H₅)₂ initiators in 1,2-dichloroethane at 30°C. They agreed closely with those determined by stopped-flow spectroscopy, and decreased with increasing monomer concentration.     

Mechanistic study on photocuring of a methacrylates copolymer by benzophenones

The types of photochemical reactions that will occur in the photosensitive resin for optical devices, poly(methyl methacrylate-co-crotyl methacrylate) (PMMA–CMA) doped with meta-benzoylbenzophenone (BBP), were investigated. Oxetane formation, hydrogen abstraction followed by radical coupling, and pinacol formation were found to occur. The quantum yield for disappearance of benzophenone (BP) in the PMMA–CMA film was estimated as 0.68. The pendant crotyl group seems to be a major photoreaction site.     

Efficient intraliposomal entrapment of hydrophilic platinum oligonuclear complexes

A simple method for intraliposomal entrapment of platinum complexes is presented, where hydrophilic platinum oligonuclear complexes, 1-methyluracil green (MeUG), uridine green (UdG) and uridine blue (UdB), are included inside liposomes and allowed to react with bilayer lipids. The liposomes prepared in this method exhibit higher entrapment efficiency and higher distribution to organs (liver, kidney, spleen, lung) and blood (but not B16 cancer cells) than those prepared from mononuclear Pt complexes [cis-diamminedichloroplatinum, cis-diammine-1,1′-dicarboxylatocyclobutaneplatinum, and cis-dichloro-cis-dihydroxy-trans-bis(isopropylamine)platinum)].