津田 哲哉

Abstract Objectives Intrapulpal calcifications can occur in the dental pulp of patients with diabetes. We focused on the association between ectopic calcifications in the dental pulp and advanced glycation end products (AGEs) in Spontaneously Diabetic Torii (SDT)‐fatty rats, an obese type 2 diabetic rat model, to determine the mechanism of calcification with pulp stone in the dental pulp. Materials and Methods Pathologic calcification in the dental pulp of SDT‐fatty rats was observed using electron microscopy and immunohistochemical analysis. Moreover, mechanical analysis of periapical region of molar tooth against occlusal force was performed. Results In SDT‐fatty rats, pathogenic pulpal calcifications occurred during blood glucose elevation after 6 weeks, and granular calcification was observed in the dental pulp after 11 weeks. Pentosidine, a major AGE, and the receptor for AGEs were strongly expressed in the dental pulp of SDT‐fatty rats. S100A8, TNF‐α, and IL‐6 also showed positive response in the dental pulp of the SDT‐fatty rat, which indicated pulpal inflammation. Blood flow disorder and hypoxic dental pulp cells were also observed. In silico simulation, strain from occlusal force concentrates on the root apex. Conclusions Glycation makes blood vessels fragile, and occlusal forces damage the vessels mechanically. These are factors for intrapulpal calcification of diabetes.

The impact of sp² carbon material species on the ORR performance of electrocatalysts prepared through the one-pot pyrolysis method with an ionic liquid was revealed by the combination of several commonly used analytical approaches.

In this article, a short-time and ultrasensitive electrochemical approach capable of detecting subtle phase changes during the charge-discharge process is introduced. It is attained through the use of a Si microparticle electrode specially prepared using the electrophoretic deposition (EPD) method. The features of the electrode are that it is binder-free and the active material is sparsely deposited onto the electrode. Despite the scan rate being 5 to 60 times faster than the usual scan rates, the cyclic voltammograms recorded at the binder-free Si microparticle electrode in the 83.3–16.7 mol% 1-ethyl-3-methylimidazolium bis(fluorosulfonyl)amide−lithium bis(fluorosulfonyl)amide ionic liquid electrolyte indicate several redox waves related to the lithiation reactions with phase transition, although it is difficult to see similar waves when using common Si composite electrodes. Co-deposition of both a Si active material and acetylene black onto the current collector using the EPD method significantly improves the sensitivity and performance of the electrode. Applying this electrode to operando scanning electron microscopy visually enables a deeper understanding of the impact of the morphology variation of the Si materials on the electrode performance within a short time.

<p>An appropriate combination of Si anodes and binary bis(fluorosulfonyl)amide-based ionic liquid electrolytes significantly improves Li-ion battery performances.</p>

© 2019 Scanning electron microscopy (SEM) for the electrode reaction in next-generation battery with ionic liquid (IL) electrolyte, which has both high stability under vacuum and an antistatic nature, is applied to the binder-free high capacity Si anode to observe the morphology change of the Si nanoparticle aggregate active material at different potentials during charge-discharge processes. In the IL electrolyte, 1-ethyl-3-methylimidazolium bis(fluoromethylsulfonyl)amide ([C2mim][FSA]) with 1.0 M lithium bis(trifluoromethanesulfonyl)amide (Li[TFSA]), the morphology greatly varied at the plateau observed at 0.200 to 0.070 V (vs. Li(I)/Li) in the charge-discharge curve during the first cycle, suggesting that phase transition of a-Si to c-Li13Si4 is a potential problematic process. After the first cycle, the lithiation process initiated at more positive potential. Similar behavior was also recognized in the Li[TFSA]‒tetraglyme solvate IL electrolyte in a 1:1 molar ratio ([Li(G4)][TFSA]).

© 2019 American Chemical Society. Pt and PtNi alloy nanoparticle-supported multiwalled carbon nanotubes (Pt/MWCNTs and PtNi/MWCNTs) are prepared by a one-pot pyrolysis method with the N,N,N-trimethyl-N-propylammonium bis(trifluoromethanesulfonyl)amide ionic liquid (IL) containing platinum and nickel precursors, Pt(acac)2, Ni[Tf2N]2, and Ni(acac)2, with suspended MWCNTs. The composite materials can be prepared by simply heating the IL solution at 573 K. The resulting materials show favorable catalytic activity toward the oxygen reduction reaction and durability superior to those of typical commercially available electrocatalysts. The catalytic activity of the PtNi/MWCNTs depends on the Ni content of the PtNi alloy nanoparticles. One of the PtNi/MWCNTs shows 1.4 times higher mass activity than a typical commercial electrocatalyst. A plot of the mass activity as a function of the Ni content gives a mountain-shaped curve with a vertex at ca. 25 atomic percent Ni. This one-pot process can readily control the catalytic properties of the PtNi/MWCNTs by changing the molar fraction of Pt and Ni precursors.

© 2019 by the authors. New types of ionic liquids (ILs) with an epoxy group on a piperidinium-type cation were successfully synthesized by the simple anion exchange reaction of a solid 1-allyl-1-(oxiran-2-ylmethyl)piperidinium bromide, which was designed in this study. Unfortunately, the physicochemical properties, e.g., viscosity and ionic conductivity, of the ILs were inferior to those of common ILs such as 1-ethyl-3-methylimidazolium tetrafluoroborate ([C2mim][BF4]) and 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)amide ([C4mim][Tf2N]). However, the resulting ILs are of great interest as reaction intermediates: For example, the epoxy group on the cation could react with various reagents, including CO2. Consequently, the modification of the cation structure in the ILs was possible. This is particularly interesting because it is very difficult to modify commonly used ILs. The approach established in this article will provide a favorable synthetic route for creating novel functional ILs in the future.

© The Author(s) 2018. Published by Oxford University Press on behalf of The Japanese Society of Microscopy. All rights reserved. X-ray micro-CT is one of the most useful techniques to examine 3D cellular architecture inside dry seeds. However, the examination of imbibed seeds is difficult because immersion in water causes a decline in the image quality. Here, we examined the use of ionic liquids for specimen preparation of chemically fixed imbibed seeds of Arabidopsis. We found that treatment with high concentrations of ionic liquids after osmium tetroxide fixation helped not only to prevent the structural damage caused by seed shrinkage, but also to preserve the image quality. Under these conditions, the cellular architecture of seeds was also well maintained.

© 2019 The Chemical Society of Japan. Polyacrylonitrile (PAN)-derived carbon beads with uniform size and high surface area were successfully prepared by the carbonization of PAN and activation by KOH. Physicochemical analysis revealed that the PAN-derived carbon beads activated by KOH possessed larger pore volume and pore width than the same types of carbon beads activated by CO2 and commercially available activated carbon powder. Even if the PAN-derived carbon beads were made into an electrode without any conducting supplements, the electrode possessed a higher specific capacitance than an electrode composed of commercially available activated carbon in the presence of conducting acetylene black powders. Origins of such desirable properties as carbon materials used for electric double layer capacitors were investigated by AC impedance measurements in both aqueous and non-aqueous electrolyte solutions.

© The Electrochemical Society of Japan, All rights reserved. Two sizes of polyacrylonitrile beads were prepared as precursors of carbon beads by varying the reaction solvent ratio of N,N-dimethylformamide to methanol for dispersion polymerization reaction. The spherical structure of the carbon beads were maintained after carbonization and activation. Charge-discharge tests and AC-impedance analyses revealed that the electric resistance between the particles is low without conducting supplements. In addition, an appropriate pore size brought by the KOH activation of smaller carbon beads lead to a better capacitor performance at high current conditions.

Based on electron microscope techniques developed for ionic liquids (ILs), which have both high stability under vacuum and an antistatic nature, specially-designed Li battery cells with all components contained in actual Li batteries were fabricated for in situ electron microscope observation. Various interesting anode behaviors in the Li battery were observed. For example, Si thin flake active material can store Li(I) electrochemically, causing the morphology to change into a ribbon-like or isotropic expanded structure. Surprisingly any damage to the Si material was not recognized by nanoscale imaging because of the thin layer structure that can release internal stress spontaneously during lithiation. In addition, the Li metal deposition process was directly observed and a similar approach can be applied to in situ X-ray photoelectron spectroscopic analysis.

The physicochemical properties and electrochemical behavior of 1-butyl-3-methylimidazolium aryltrifluoroborate ([C4mim][ArBF3]) with various substituents, e.g., methoxy, fluoro, trifluoromethyl, and cyano groups, introduced on the phenyl moiety on the anion are examined. Several position isomers of the [ArBF3]- anion are also prepared to provide further insight into the effect of the position. The equivalent conductivity and the electrochemical stability for some [C4mim][ArBF3] room-temperature ionic liquids (RTILs) is qualitatively discussed from the results of quantum chemical calculations of the cation-anion interaction and the HOMO energy level of the anion. Interestingly, [C4mim][ArBF3] RTILs with an electron-withdrawing group on the phenyl moiety electrochemically form an ion-selective membrane on a Pt electrode, and only neutral and cationic species can pass through the membrane.

Pt-nanoparticle-supported carbon catalysts for the electrochemical oxygen reduction reaction produced using a Pt-nanoparticle-monodispersed ionic liquid (IL) show better durability than a commercially available catalyst due to the small amount of IL between the Pt nanoparticles and the carbon support. In this study, to add further functionality to the catalysts prepared with the Pt-nanoparticle-monodispersed IL, a protic organic salt, diphenylammonium hydrogen sulfate ([DPA][HSO4]), and a protic ionic liquid, N,N-diethyl-N-methylammonium hydrogen sulfate ([DEMA][HSO4]), are employed for catalyst preparation. Interestingly, the mass activity and durability of the resulting catalyst are significantly enhanced by the addition of an electrochemically polymerizable [DPA][HSO4] to the Pt-nanoparticle-monodispersed [DEMA][HSO4] because of the formation of a conducting polymer, poly(diphenylamine), between the Pt nanoparticles and the carbon support during potential cycling.

Because ionic liquids (ILs) have numerous various interesting features, they are recognized as important functional reaction media and liquid materials. Several applications that take advantage of each feature have been proposed. The combination of a set of unique features, which includes negligible vapor pressure, good chemical/electrochemical stability, as well as antistatic properties, has led to the creation of some novel analytical techniques wherein the IL is used with analysis equipment that requires vacuum conditions, e.g., SEM, TEM, and XPS. In recent times, vacuum analytical techniques that employ ILs have had a significant impact on a wide variety of science and technology applications. In this chapter, recent ionic liquid-electron microscopy techniques, including associated electron-beam irradiation techniques such as energy dispersive X-ray spectrometry, electron diffraction, and ionic liquid-X-ray photoelectron spectroscopy are introduced. The former is often employed for in situ observation of electrochemical reactions in next-generation battery systems and for monitoring nanoparticle production/growth processes in ILs, and the latter can reveal IL structure at the vacuum-IL phase boundary as well as chemical/electrochemical reactions in ILs on a molecular scale.

© North Carolina State University. A functional ionic liquid 1-butyl-3-vinylimidazolium iodide ([BuVyIm]I) was synthesized, and it exhibited the features of both decay resistance and leaching resistance after in-situ polymerization within wood. Treated wood specimens of Cryptomeria japonica were evaluated in this preliminary study using leaching tests with distilled water and decay tests for 12 weeks with brown rot fungi Fomitopsis palustris. The [BuVyIm]I polymerized by 100 kGy 60Co gamma irradiation was retained in wood after 10 wash and dry cycles, whereas nearly all of the [BuVyIm]I was washed out in the cases of 10 kGy and no irradiation. The decay testing of these specimens showed that sapwood had a different decay resistance depending on the strength of gamma irradiation used, whereas the treated heartwood did not support fungal growth. The results of this study imply that [BuVyIm]I polymerized by 100 kGy gamma irradiation have potential for wood preservation.

© 2018 The Electrochemical Society of Japan, All rights reserved. In order to clarify the nanoparticles formation process of the metal sputtering onto ionic liquid, which is the facile method to prepare metal nanoparticles, the vacuum-liquid interface was captured by a camcorder while conducting gold sputtering. Because of intense color of Au clusters, move of Au clusters by convection of ionic liquid was clearly observed. The convection is a dominant factor in a transport of the resulting Au nanoparticles from the surface to interior of the ionic liquid.