吉田 優

Flushナイフは送水機能付きのショートニードルナイフである.シース先端および辺縁をプロテクターとして用いることで切開・剥離ともに連続した操作が可能である.食道では2mmタイプを用い,まず口側の横切開から肛門側横切開までCの字を書くように粘膜切開を行う.次いで切開縁のトリミングを行い同部粘膜下層を溝状に剥離する.水没しやすい場合はさらに溝を広げ水没領域から脱しておく.次いで反対側の粘膜切開とトリミングを終え,剥離操作に移る.剥離も2mmタイプを使用し,困難局面では1mmタイプが有用である.通常追加局注はナイフからの送水で十分であるが,シリンジを用いてヒアルロン酸ナトリウムをナイフから注入することも可能である.2/3周を越えるような病変はトンネル法の併用が有効で,送水による鈍的剥離を利用することで効率的なトンネル形成が可能である.食道はFlushナイフの有用性が顕著な臓器である.(著者抄録)

The title compound, C(26)H(20), lies about an inversion centre. The naphthalene unit and the hexatriene chain are each approximately planar ( maximum deviations of 0.0143 and 0.0042 angstrom, respectively), and are inclined to one another at a dihedral angle of 49.20 (4)degrees. The dihedral angle between the two naphthalene ring systems of neighboring molecules is 85.71 (4)degrees.

We investigated the permeation behavior of Li, Co, and Ni ions through thermo and pH-responsive gel membranes, which were prepared by gamma-ray grafting of pH-responsive poly(acrylic acid) (poly(AAc)) onto a thermo-responsive polymer gel of acryloyl-L-proline methyl ester (A-ProOMe). Using 15% AAc grafted membranes, the permeation constants of Li ions are 2.8 and 3.5 times higher than those of Co and Ni ions in a pH 6.0 buffer solution at 30 degrees C. These ratios are two and three times higher than those of 5 and 43% grafted gel membranes, respectively. By comparison with the permeation of metal ions through the non-thermo-responsive porous polyethylene membranes grafted with AAc chains or random copolymer gel membranes (poly(A-ProOMe-co-AAc)), it is clear that the structure in which adjacent carboxyl groups of poly(AAc) are surrounded by thermo-responsive A-ProOMe matrix causes selective permeability of Li ion over Co and Ni ions. The distributions of Co and Ni ions in the microscopic structures clearly show that the structure consisting of flexible chains of the carboxyl groups grafted onto the thermo-response gel membrane plays a decisive role in the superior selective permeation of a Li ion.

Novel method for preparing aromatic hydrocarbon proton-conductive membranes without sulfonation and membrane casting process is achieved by radiation-grafting of sodium styrenesulfonate to an aromatic polyamide, poly(m-xylylene adipamide) (Nylon-MXD6) films and subsequent ion-exchange. The styrenesulfonate was easily grafted into the Nylon-MXD6 films from an oxygen-free dimethyl sulfoxide (DMSO) Solution at 60 degrees C. As a result, the resulted styrenesulfonic acid-grafted Nylon-MXD6 films, namely proton-conductive membrane, with high ion-exchange capacity up to 1.63 mmol/g, can be obtained. The membrane was transparent and highly hydrophilic. The proton conductivity, water uptake and methanol permeability of the proton-conductive membranes were investigated with respect to their use in fuel cells. The high proton conductivity reached 0.083 S/cm, comparable to Nafion. Furthermore, the methanol permeability was significantly lower than that of the Nafion membrane. Therefore, the Nylon-MXD6-based proton-conductive membrane is a more promising material for the direct methanol fuel cells (DMFCs). (C) 2008 Elsevier B.V. All rights reserved.

Pectin and triallylisocyanurate (TAIC) were immobilized onto poly (styrene-co-divinylbenzene) (PSD) beads by irradiating in the range of 2.5 to 25 kGy using gamma-rays from a Co-60 source. The adsorption performance of methyl-2-benzimidazolylcarbamate (MBC) treated with immobilized Pectin-TAIC beads was investigated. Pectin was effective to enhance the MBC uptakes at pH I], in contrast to pH 3 for TAIC. The amounts of MBC uptake of immobilized Pectin-TAIC beads were 1.3 similar to 3.9 times higher than those of PSD beads which were only irradiated without the use of Pectin and TAIC in the range of pH 3 to pH 11. The difference was due to the introduction of both the hydrophilicity and hydrophobicity for immobilized beads by gamma-irradiation. Ten cycles of adsorption-desorption assays show that the sorption performance of immobilized Pectin-TAIC beads shows excellent reproducibility, suggesting that the immobilized Pectin-TAIC beads are a useful adsorbent for the extraction of MBC from environmental water.

BACKGROUND: The purpose of this study was to visualize the gastric wall layers and to depict the vascular architecture in vitro by using resected porcine stomachs studied with high-spatial resolution magnetic resonance (MR) imaging. METHODS: Normal dissected porcine stomach samples (n = 4) were examined with a 3 Tesla MR system using a newly developed surface coil. MR images were obtained by the surface coil as receiver and a head coil as transmitter. High-spatial-resolution spin-echo MR images were obtained with a field of view of 8 x 8 cm, a matrix of 256 x 128 and slice thicknesses of 3 and 5 mm. RESULTS: T1 and T2-weighted MR images clearly depicted the normal porcine gastric walls as consisting of four distinct layers. In addition, vascular architectures in proper muscle layers were also visualized, which were confirmed by histological examinations to correspond to blood vessels. CONCLUSIONS: High-spatial-resolution MR imaging using a surface coil placed closely to the gastric wall enabled the differentiation of porcine gastric wall layers and the depiction of the blood vessels in proper muscle layer in this experimental study.

Structural characterization of a hydrogel consisting of an oligomeric electrolyte, poly[pyridinium-1,4-diyliminocarbonyl-1,4-phenylenemethylene chloride] (1-Cl) as an ionic gelator was carried out by static and dynamic light scattering (SLS/DLS) and small-angle neutron scattering (SANS) techniques. All the measurements were performed by changing the concentration and temperature. We have successfully obtained the weight average molecular weight and the degree of polymerization of poly(1-Cl) by SLS. The sol-gel transition was clearly observed as large fluctuations in the scattering intensity of the time-intensity correlation function. Time correlation function of the scattering light intensity entailed a power law behavior at the sol-gel transition. 1-Cl hydrogel showed strong hysteresis and its hysteresis loop was observed both by DLS and theological methods. We have estimated the critical concentration of gelation and the gelation temperature by DLS. The enthalpy change for gelation was estimated to be ca. - 10 kJ/mol. SANS experiments revealed that the unit structure of the gel network is responsible for the gelation of 1-Cl hydrogel.

Ionene Polymers with N,N'-(p-phenylene)dibenzamide linkages were synthesized in high yields by the copolymerization of 1,4-bis[4-(chloromethyl)benzamide] benzene and alpha, omega-ditertiary amines in N,N-dimethylformamide. The ionene polymers provided physical hydrogels under ca. 1-5 wt % of the concentrations after heating and cooling at room temperature without any other additives. The gelation ability was dependent on the diamine spacers and/or the molecular weights, and the ionene polymer with the longest hexylene linker connecting ammonium cations was the most effective gelation capability in water among these ionene polymers. In the theological measurement, the hydrogel showed a unique thixotropic nature that was a fast self-recovering property after the continuous oscillatory shear stress. Furthermore, the ionene polymer has an additional function as a dispersant for single-walled carbon nanotubes (SWNT) in water.

The hydrogel consisting of an oligomeric electrolyte, poly[pyridinium-1,4-diyi-iminocarbonyl-1,4-phenylenemethylene chloride] (1-Cl) underwent self-healing at temperatures lower than its gelation temperature after destruction of the gel network in a shear flow. The self-healing mechanism was investigated by theological measurements on three different kinds of gels including a low-molecular weight organogelator and a polymeric hydrogelator. Although all of the three gels exhibited thermo-reversible hysteresis loops in the shear moduli, only 1-Cl hydrogel recovered its mechanical properties after vigorous agitation. It is conjectured that the self-healing is due to formation of network structure via a chlorine ion mediated hydrogen bond for which the activation energy is on the order of 10 kJ/mol.

To prepare a crosslinked hybrid polymer electrolyte membrane (PEM) with high chemical stability, a silane monomer, namely p-styryltrimethoxysilane (StSi), was first grafted to poly(ethylene-co-tetrafluoroethylene) (ETFE) film by gamma-ray preirradiation. Hydrolysis-condensation and sulfonation were then performed on the StSi-g-rafted ETFE (StSi-g-ETFE) films to give them crosslinks and proton conductibility, respectively. Thus, a crosslinked proton-conducting hybrid PEM was obtained. The crosslinks introduced by the silane-condensation have an inorganic -Si-O-Si-structure, which enhance the chemical and thermal stabilities of the PEM. The effect of the timing of the hydrolysis-condensation (before or after sulfonation) and the sulfonation method (by chlorosulfonic acid or H2SO4) on the properties of the resulting hybrid PEMs such as ion-exchange capacity, proton conductivity, water uptake, chemical stability, and methanol permeability were investigated to confirm their applicability in fuel cells. We conclude that the properties of the new crosslinked hybrid StSi-grafted PEMs are superior to divinylbenzene (DVB)-crosslinked styrene-grafted membranes. (C) 2008 Wiley Periodicals, Inc.

Polymer films with acid-responsive chromic dyes and acid generators have been designed for an electron-beam (EB)-induced color imaging system. Arylsulfonic acid esters and triphenylsulfonium salts were used as an EB-sensitive acid generator; the acid (H+) allows a chromic reaction with rhodamine B base (RB) and 4,4'-bis(dimethylamino)benzhydrol (BH) to be triggered. Upon EB irradiation, poly(methyl methacrylate) (PMMA) films consisting of RB or BH and acid generators exhibited a characteristic absorption band with lambda(max) at 560 and at 612 rim, respectively, and an isosbestic point. These spectral changes clearly indicate that colorless chromic dyes in PMMA are transformed selectively to the colored form The color imaging of these films was performed by electron-beam direct writing (EBDW) with a 50 nm diameter beam to form 100-1000 nm line and space patterns and evaluated by optical and confocal laser microscopy. EBDW on the acid-chromic polymer films, especially for BH, yielded clear color imaging of 100-200 nm line and space patterns with a dose of only 10 mu C cm Confocal laser microscopy gave thinner lines than the laser wavelength (632.8 nm), probably because of the large change in refractive index of the patterned film induced by EB irradiation even with a low-energy dose.

Polyetheretherketone (PEEK)-based polymer electrolyte membrane (ssPEEK) was prepared by successive grafting of divinyl benzene (DVB) and ethyl styrenesulfonate (ETSS) onto PEEK film, followed by hydrolysis of the ETSS graft chains to form styrenesulfonate (SS) graft chains. In comparison with the commercial Nafion membrane, the obtained ssPEEK membrane possesses superior proton conductivity and mechanical property, comparable fuel cell performance at a lower temperature and higher relative humidity (80 degrees C, 100 RH%), and substantially better fuel cell performance at a higher temperature and lower relative humidity (95 degrees C, 40 RH%). Furthermore, the ssPEEK membrane maintains good performance in a fuel cell after operation at 95 degrees C and 40 RH% for more than 250 h, while the Nafion membrane deteriorated under such conditions. (C) 2008 Elsevier B.V. All rights reserved.

The effect of grafting solvents, such as isopropanol (iPrOH), tetrachloroethane (TCE), tetrahydrofuran (THF), and toluene, on the preparation of poly(ethylene-co-tetrafluoroethylene)-graft-poly(styrene sulfonic acid) (ETFE-g-PSSA) electrolyte membranes by the gamma-ray preirradiation grafting method was investigated. It was found that the iPrOH can drastically accelerate the grafting, resulting in a higher degree of grafting. However, for an appropriate degree of grafting of about 50%, the sulfonic acid groups in the ETFE-g-PSSA membrane prepared with the iPrOH were mainly distributed near the membrane surface, as shown by low proton conductivity in the membrane thickness direction. In contrast to this result, the ETFE-g-PSSA membranes prepared with the THF, toluene and TCE exhibited uniform distribution of the sulfonic acid groups in the membrane. Especially, in the case of the TCE grafting solvent, the chemical stability of the resultant electrolyte membrane was clearly higher than those prepared with the other grafting solvents. (C) 2007 Elsevier Ltd. All rights reserved.

Citrobacter rodentium, a murine model pathogen for enteropathogenic Escherichia coli, colonizes the colon utilizing attaching and effacing lesions to adhere specifically to the surfaces of intestinal epithelial cells and cause mucosal inflammation. CD4+ T cells, B cells, and immunoglobulin G (IgG), but not secretory IgA or IgM, play a critical role in eradicating this pathogen. Consistent with the importance of IgG in C. rodentium eradication, IgG transport by the neonatal Fc receptor for IgG within the intestinal epithelium also has a critical role in the regulation of C. rodentium infection. It remains to be determined, however, whether Fcgamma receptors (FcgammaRs), the receptors for the Fc portion of IgG, regulate this bacterial infection within mucosal tissues. Therefore, we investigated the roles of FcgammaRs during C. rodentium infection. Fc receptor common gamma chain (FcRgamma)-deficient mice were more susceptible to C. rodentium-induced colitis. This occurred through decreased efficiency of FcR-mediated endocytosis and maturation of dendritic cells and consequently T-cell activation of antigen-specific T cells. Moreover, in the absence of FcgammaRs, phagocytosis by macrophages was significantly diminished. Therefore, activating FcgammaRs play an important role in defending against C. rodentium infection, indicating that the critical role played by IgG in this infection is not mediated by IgG alone but is dependent upon this class of receptors.

A polysulfonamide and copolymers consisting of sulfonamides and amides underwent Fries rearrangement and scission, forming amino groups upon EB irradiation. The EB irradiation of these films with a dose of 500 mu C.cm(-2), followed by the color forming reaction provided the color imaging of line/space patterns with a resolution of 300 nm.

Poly(ethylene-co-tetrafluoroethylene) (ETFE) films were irradiated by swift heavy ion-beams of Xe-129(23+) with fluences of 0, 3 x 10(6), 3 x 10(7), 3 x 10(8) and 3 x 10(9) ions/cm(2), followed by gamma-ray pre-irradiation for radiation grafting of styrene onto the ETFE films and sulfonation of the grafted ETFE films to prepare highly anisotropic proton-conducting membranes. The fluence of Xe ions and the addition of water in the grafting solvent were examined to determine their effect on the proton conductivity of the resultant membranes. It was found that the polymer electrolyte membrane prepared by grafting the styrene monomer in a mixture of 67% isopropanol and 33% water to the ETFE film with an ion-beam irradiation fluence of 3.0 x 10(6) ions/cm(2) was a highly anisotropic proton-conducting material, as the proton conductivity was three or more times higher in the thickness direction than in the surface direction of the membrane. (c) 2007 Elsevier B.V. All rights reserved.

Geochronologic data and arguments proposing the division of the pre-Pan-African terranes of East Antarctica (Grenvillian Circum-East Antarctic Orogen) into three genetically different provinces, and the recognition of the Pan-African orogens as sutures are discussed. Problems of zircon U-Pb dating for identifying the absence of precursor Grenvillian events, which are superimposed and concealed by the dominant Pan-African event, are specifically highlighted. Major problems are (i) the lowering of closure temperatures under deformational and/or fluid-rich conditions, (ii) the weighted mean U-Pb concordant ages, (iii) the disappearance of an earlier discordia in the polymetamorphism, (iv) diversity in the interpretation of zonal structure of zircons, (v) general lack of discussion on the formative process of the dated zircons and (vi) the practical difficulty in zircon geochronology for providing evidence of the absence of earlier events superposed by a later high-grade event. It is stressed that it is difficult for zircon geochronology to provide robust evidence for eliminating the possibility of the existence of earlier tectonothermal events superimposed by later high-grade events. The presence of Grenvillian-age basement within the Pan-African terranes and the former linkage of now-separated Grenvillian age belts in East Antarctica cannot therefore be excluded from U-Pb zircon evidence alone. (C) 2006 International Association for Gondwana Research. Published by Elsevier B.V. All rights reserved.

Novel one-step preparation of polymer electrolyte membranes without a membrane casting process is achieved by radiation crosslinking of a polyetheretherketone (PEEK) film to prevent dissolution and deformation of the original film in sulfonating solutions. The films crosslinked with doses more than 33 MGy can be effectively sulfonated in a chlorosulfonic solution, resulting in a crosslinked sulfonated PEEK (sPEEK) electrolyte membrane with high proton conductivity comparable to Nafion. Nevertheless, its water uptake was high for application in fuel cells. The thermal treatment was effective for further crosslinking of the membrane; as a result, the water uptake and methanol permeability of the double crosslinked sPEEK membranes drastically decreased, compensating for a slight decrease of proton conductivity. In addition, unlike the traditional cast sPEEK membrane showing the irreversible swelling in hot water, the double crosslinked sPEEK membranes exhibited excellent stability toward 100 degrees C hot water for more than 200 h without any decrease in proton conductivity, and had the mechanical and thermal properties superior to those of Nafion. (c) 2007 Elsevier Ltd. All rights reserved.

We prepared a novel oligomeric electrolyte that acts as a multifunctional gelator. The gelator has the following notable characteristics: (1) facile preparation in one pot involving condensation and subsequent intermolecular quaternization reaction; (2) tunable solubility to apply to various solvents (e.g., organic, aqueous) and ionic liquids by a simple anion-exchange reaction; (3) resistant to acids; (4) fast recovery of the mechanical strength after stress; (5) synergistic use as dispersant for single-wailed carbon nanotubes (SWNT).

A novel process comprising the UV-induced photografting of styrene into poly(tetrafluoroethylene) (PTFE) films and subsequent sulfonation has been developed for preparing proton-conducting membranes. Although under UV irradiation the initial radicals were mainly generated on the surface of the PTFE films by the action of photosensitizers such as xanthone and benzoyl peroxide, the graft chains were readily propagated into the PTFE films. The sulfonation of the grafted films was performed in a chlorosulfonic acid solution. Fourier transform infrared and scanning electron microscopy were used to characterize the grafted and sulfonated membranes. With a view to use in fuel cells, the proton conductivity, water uptake, and mechanical properties of the prepared membranes were measured. Even through the degree of grafting was lower than 10%, the proton conductivity in the thickness direction of the newly prepared membranes could reach a value similar to that of a Nafion membrane. In comparison with T-ray radiation grafting, UV-induced photografting is very simple and safe and is less damaging to the membranes because significant degradation of the PTFE main chains can be avoided. (c) 2007 Wiley Periodicals, Inc.

The preparation of ion-track membranes of thermally stable poly(p-phenylene terephthalamide) (PPTA) was performed by ion beam irradiation followed by chemical etching with a sodium hypochlorite solution. Cylindrical pores were observed in the membrane irradiated with Au-197 and U-238 ions at an energy of 11.1 MeV/n. In contrast, funnel shape pores appeared in the membrane irradiated with Kr-84, Ru-102 and Xe-129 ion at energies of 6.2, 3.6 and 3.5 MeV/n, respectively. The Au-197 and U-238 ion irradiation was found to exhibit more than four times larger sensitivity to the track etching under the same etching conditions. Consequently, the pore shape can be controlled by the masses and energies of the irradiated ions, in close relation to the etching sensitivity of the track. (C) 2007 Published by Elsevier B.V.

In order to prepare a polymer electrolyte hybrid membrane with both high proton conductivity and high thermal stability, an aromatic vinyl monomer having a trimethoxysilyl group, namely p-styryltrimethoxysilane, was first grafted into poly(ethylene-co-tetrafluoroethylene) (ETFE) film by gamma-ray preirradiation. The p-styryltrimethoxysilane-grafted film was then sulfonated to attach sulfonic acid groups onto the aromatic rings of the graft chains, and finally hvdrolyzed and condensed to introduce silane-crosslinking between the graft chains. Thus, a crosslinked proton-conducting polymer electrolyte hybrid membrane was obtained. The preparation conditions for grafting and sulfonation, and the properties of the resulting polymer electrolyte membrane, such as ion exchange capacity, proton conductivity, water uptake, and thermal stability were investigated with respect to its application in fuel cells. It is concluded that the properties of the new p-styryltrimethoxysilane-grafted polymer electrolyte hybrid membrane are comparable to Nafion, and are superior to a styrene-grafted membrane. (C) 2007 Elsevier B.V. All rights reserved.

Assembled systems consisting of an azobenzene moiety as the photofunctional component and valyl units as the network backbone are investigated. The molecular ordering of these assemblies is examined by spectroscopy and theoretical calculations. The number of valyl units greatly influences the molecular order in the organized systems. Only N-(L-valyl-L-valyl-L-valyl)azobenzene-4-carboxamide (3) forms a complete beta-sheet structure in this artificial assembly. Upon photoirradiation, the azobenzene moieties isomerize completely, revealing the reversibility in the structural organization through the flexibility of the beta-sheet network in this system.

Sum-frequency generation vibrational spectroscopy was used to study the molecular structure of surface-grafted poly(N-isopropylacrylamide) (PNIPAM) in air and in D2O. It was found that the side chains of the PNIPAM were nearly standing at the air/PNIPAM interface, owing to the hydrophobic nature of the isopropyl groups. Total internal reflection geometry was employed to obtain SFG spectra of the D2O/PNIPAM interface. When the water temperature was increased, red shifts of the SFG peaks were observed. This can be explained by the dehydration of the alkyl groups at the water interface. From the quantitative analysis of the molecular orientation, restructuring of the main chain due to the dehydration occurs at the water/PNIPAM interface is suggested.

In this study the fluoropolymers, poly(ethylene-co-tetrafluoroethylene) (ETFE) and poly(vinylidene fluoride) (PVDF) films, together with the radiation-induced crosslinked polytetrafluoroethylene (cPTFE) film were compared on the basis of their preparation and properties of radiation-grafted polymer electrolyte membranes. The polymer electrolyte membranes were prepared by radiation grafting of styrene into the base films and subsequent sulfonation. The proton conductivity and chemical stability of the three types of membranes with a similar ion exchange capacity (IEC) near 1.0 mmol/g were investigated and are discussed in detail. Although the ETFE-based polymer electrolyte membrane was relatively more stable, its proton conductivity was lower than those of the PVDF- and cPTFE-based membranes. On the other hand, the cPTFE-based membrane showed a significantly higher proton conductivity, but its chemical stability was shorter than that of the ETFE-based membrane. It is considered that the difference in the preparation and properties of the polymer electrolyte membranes was due to the difference in the degree of crystallinity as well as in the chemical structure of the fluoropolymer base films. (c) 2006 Wiley Periodicals, Inc.

The influence of pre-irradiation atmosphere, argon and air, on radiation grafting of styrene into poly(ethylene-co-tetrafluoroethylene) (ETFE) films and the properties of the ETFE-based radiation-grafted polymer electrolyte membranes were investigated. The preparation and properties of the membranes were found to be strongly influenced by the gamma-ray pre-irradiation atmosphere. The proton conductivity was measured in its water-saturated state at 25 degrees C, and the membrane durability was tested in a 3% H2O2 aqueous solution at 60 degrees C. The proton conductivity of the membrane prepared by pre-irradiation under air was higher than that of the membrane prepared under argon with the same ion exchange capacity level. However, the durability of the former was considerably lower than that of the latter. For instance, the membrane with an ion exchange capacity of about 1.0 mmol g(-1) prepared under argon was twice as durable as that prepared under air. It was considered that the lower durability of the membrane prepared by pre-irradiation under air was because of the unstable ether bond introduced between the graft chains and the backbone chains.

Proton exchange membranes for use in fuel cells were prepared by our original ion-track technology, which involves (i) the swift heavy ion irradiation of polyvinylidene fluoride films and subsequent chemical etching to obtain cylindrical pores, and (ii) the filling of proton-conducting polymer chains into the etched pores by gamma-ray-induced graft polymerization. We found that the membranes possessed one-dimensional straight proton conducting pathways parallel to the ion-beam incident axis. Such restricted structures probably led to less water uptake and lower methanol permeability compared to a commercially-available Nafion membrane.

We prepared novel ion exchange membranes for possible use in polymer electrolyte fuel cells (PEFCs) by the radiation-induced graft copolymerization of styrene and new crosslinker bis(vinyl phenyl)ethane (BVPE) into crosslinked polytetrafluoroethylene (cPTFE) films and subsequent sulfonation and then investigated their water uptake, proton conductivity, and stability in an oxidizing environment. In contrast to the conventional crosslinker divinylbenzene (DVB), the degree of grafting of styrene/BVPE increased in spite of high crosslinker concentrations in the reacting solution (up to 70 mol %). Quantitative sulfonation of the, aromatic rings in the crosslinked graft chains resulted in the preparation of membranes with a high ion exchange capacity that reached 2.9 meq/ g. The bulk properties of the membranes were found to exceed those of Nafion membranes except for chemical. stability. The emphasis was on the fact that the BVPE-crosslinked membranes exhibited the higher stability in the H2O2 solution at 60 degrees C compared to the noncrosslinked and DVB-crosslinked ones, as well as decreased water uptake and reasonable proton conductivity. These results tire rationalized by considering the reactivity between styrene and the crosslinker, which is an important factor determining the distribution of the crosslinks in the graft component. In the case of BVPE, the crosslinks at a high density were homogeneously incorporated even into the interior of the membrane because of its compatibility with styrene while the far too reactive DVB led to a crosslink formation only near the surface. The combination of both the cPTFE main chain and BVPE-based grafts, i.e., a perfect "double" crosslinking structure, is likely to effectively improve the membrane performances for PEFC applications.

The Kibaran Supergroup, a >= 13000-km-long belt of metasedimentary and igneous rocks in the southeastern Congo, is in a critical location between the Congo Craton (sensu stricto) and the Tanzania-Bangweulu Block. Understanding its tectonic evolution will shed much-needed light on the amalgamation history of sub-Saharan Africa. This study presents U-Pb SHRIMP age data for 150 detrital zircons from four metasedimentary formations of the Nzilo Group, the middle lithostratigraphic unit within the Kibaran Supergroup in Katanga Province. These samples yielded dates between 3214 +/- 7 and 1329 +/- 32 Ma. Prismatic Mesoproterozoic detrital zircons (dated at 1499 +/- 49 to 1329 +/- 32 Ma, with a peak at 1380 Ma) occur in all samples and are inferred to be derived from the Mitwaba orthogneisses, which intrude the Kiaora Group, the oldest lithostratigraphic unit of the Kibaran Supergroup. More than three-quarters of the zircon population is composed of recycled grains, yielding dates between and Ma, with 2434 +/- 5 1696 +/- 18 peaks at 2050 and 1850 Ma. These peaks overlap with the timing of geological events in the adjacent Paleoproterozoic Bangweulu Block, including the Ubendian-Usagaran belts. Archean zircons were not found in the oldest Nzilo units and are restricted to the youngest Nzilo rocks, where they form only a minor component (<6%) of the zircons recovered. The Archean zircons are inferred to be derived from the unroofing of successively older crust in the East African lithosphere. U-Pb data support field observations and indicate that the Nzilo Group sediments postdate the similar to 1.38-Ga Kibaran syn-D-1 igneous rocks and received some detritus from them. The lithostratigraphic and geochronological data, coupled with the regional geology, indicate that a substantial portion of the Nzilo Group detritus came from interbasinal reworking of the underlying Kiaora Group and its associated 1.38-Ga orthogneisses, with a significant contribution from the Tanzania-Bangweulu Block. The data support a previously proposed subductional model for the Kibaran belt and constrain the paleotectonic environment during the deposition of the Nzilo Group.

The polymerization of trifluorovinyl heptafluoropropyl ether (CF2=CF-O-C3F7) (FVPE) was investigated by gamma-rays irradiation to afford high-molecular weight polymer of FVPE. (c) 2006 Elsevier B.V. All rights reserved.

OBJECTIVE: Recently guidelines for the treatment and prevention of ulcers induced by nonsteroidal anti-inflammatory drugs (NSAIDs) have been established. The aim of the present study was to examine factors influencing orthopedists in Japan in the use of cytoprotective drugs to prevent NSAID-associated gastrointestinal adverse events. METHODS: We sent a questionnaire to 402 orthopedists in Hyogo Prefecture. A standardized 10-item questionnaire was used to collect information on NSAID prescriptions (drug name, pharmaceutical form, doses, and duration of use) and associated drugs, especially gastroprotective drugs. RESULTS: Two hundred eight (51.7%) orthopedists returned the questionnaire. The most frequently used NSAIDs, in descending order, were loxoprofen sodium, diclofenac sodium, and etodolac. Most doctors (80%) reported patients with abdominal symptoms associated with NSAIDs. Of these doctors, 59% treated the symptoms by themselves, and prescribed gastroprotective agents (32.2%), histamine H2-receptor antagonists (H2RAs) (26.4%), prostaglandin analogues (PAs) (17.0%), or proton pump inhibitors (PPIs) (16.2%). Sixty-seven percent of doctors reported that those drugs reduced the symptoms. Most orthopedists (96%) prescribed some type of drug to prevent NSAID-associated gastrointestinal events, including gastroprotective drugs (44.6%), H2RAs (19.5%), PAs (17.4%), and PPIs (10.8%). The doctors reported that they prescribed medicines for NSAID-associated gastrointestinal events on the basis of their experience (23%), by considering medical insurance restrictions (17%), and by referring to information provided by pharmaceutical company representatives (16%). CONCLUSION: Most orthopedists prescribe some type of drug to prevent NSAID-induced ulcers but do not refer to the guidelines. We therefore strongly recommend that the guidelines be made more widely known to gastroenterologists and to physicians in every field of clinical practice, including orthopedics.

Recent geochronologic data of detrital zircons and neodymium isotopic signatures of the Himalaya, Arabian-Nubian Shield, and Western Australia-East Antarctica (the Pinjarra Orogen/Circum-East Antarctic Orogen) are assessed to estimate the location of Neoproterozoic basement of the Himalaya.The protolith of the Higher Himalayan Gneisses is considered to have been derived from the Pinjarra Orogen/Circum-East Antarctic Orogen of Western Australia-East Antarctica, and not from the Indian Craton to the south. This conclusion strongly suggests the juxtaposition of the Indian Craton, which forms the basement of the Himalaya, with the Circum-East Antarctic Orogen during the Neoproterozoic when the protolith of the Higher Himalayan Gneisses deposited. (c) 2006 International Association for Gondwana Research. Published by Elsevier B.V. All rights reserved.

A novel process comprising UV-induced photografting of styrene into poly(tetrafluoroethylene-co-ethylene) (ETFE) films in vapor and liquid phases, followed by electron beam-induced crosslinking to the ETFE-graft-polystyrene films, and finally sulfonation of the multiple-crosslinked films has been developed for preparing polymer electrolyte fuel cell membranes. The significance of this process is that the photografted polystyrene chains can completely penetrate into the base ETFE film; the resultant sulfonated electrolyte membranes show proton conductibility available for fuel cell applications. On one hand, the proton conductivity of the liquid-phase photografted electrolyte membranes is higher than the vapor-phase one, and is anisotropic in the surface and thickness directions. On the other hand, radiation-induced crosslinking greatly improves the chemical stability of the resultant fuel cell membranes, and maintains the surface concentration of sulfonic acid groups at its higher level, which are very important for the performance of the relevant membrane electrode assembly. (c) 2006 Elsevier B.V. All rights reserved.

The electron-beam (EB)-induced reaction of triphenylsulfonium methanesulfonate (1-Ms) in the solid state afforded the benzene-substituted product, biphenyldiphenylsulfonium methanesulfonate (2-Ms), which has not been observed by either photolysis or EB-induced reaction in a solution. Biphenyl salt 2-Ms was accumulated as an intermediate product at an early stage and consequently decomposed to diphenylsulfide (3) and three regioisomers of phenylthiobiphenyls (4). The kinetic data of both formation and consumption of 2-Ms revealed that the biphenyl salt 2-Ms exhibited 3.7 times greater kinetic constants for consumption than that of 1-Ms. The EB-induced reaction of benzene-substituted triphenylsulfonium salts, p-biphenyldiphenylsulfonium methanesulfonate (2p-Ms) and (4-phenylthiophenyl)diphenylsulfonium methanesulfonate (7), showed the consumption rates of 3.8 and 5.7 times greater than that of 1-Ms. The sulfonium salts with aromatic counteranions showed somewhat higher reactivity than those with aliphatic counteranions. Accordingly, it is concluded that the triphenylsulfonium salts having aryl,groups, which exhibit lower ionization potential, in both cation and anion moieties should exhibit greater decomposition rates. Detailed kinetic analysis of 1-Ms revealed that the EB-induced reaction of 1-Ms comprises two disparate pathways, one pathway is a unimolecular rearrangement via the lowest excited state leading to only orthoisomer of 4 and the other is a bimolecular displacement of phenyl radical via the upper excited state leading to 2-Ms and 3. (c) 2006 American Vacuum Society.