13,945 results on '"Miura, A"'
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2. Pseudo Master Curve Analysis of an Infinite Number of Parallel First-Order Reactions: Improved Distributed Activation Energy Model
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Kouichi Miura
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Chemistry ,QD1-999 - Published
- 2024
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3. A Teaching Tool for Molecular Kinetics
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Imai, Izumi, Kamata, Masahiro, and Miura, Naosuke
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Kinetic models of a gas can be hard for students to understand. Typical tools do not display events at the microscopic level, yet computer simulations of the molecules lack a hands-on aspect. Here a new tool is described that combines the squeezing of a syringe with a computer simulation, and it is shown that this has worked well in class for both teachers and students. (Contains 10 figures and 1 footnote.)
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- 2003
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4. Applying Deep Generative Neural Networks to Data Augmentation for Consumer Survey Data with a Small Sample Size
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Shinya Watanuki, Katsue Edo, and Toshihiko Miura
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GAN ,synthesized data ,marketing research ,marketing science ,small- and medium-sized enterprises ,rare populations ,Technology ,Engineering (General). Civil engineering (General) ,TA1-2040 ,Biology (General) ,QH301-705.5 ,Physics ,QC1-999 ,Chemistry ,QD1-999 - Abstract
Questionnaire consumer survey research is primarily used for marketing research. To obtain credible results, collecting responses from numerous participants is necessary. However, two crucial challenges prevent marketers from conducting large-sample size surveys. The first is cost, as organizations with limited marketing budgets struggle to gather sufficient data. The second involves rare population groups, where it is difficult to obtain representative samples. Furthermore, the increasing awareness of privacy and security concerns has made it challenging to ask sensitive and personal questions, further complicating respondent recruitment. To address these challenges, we augmented small-sized datawith synthesized data generated using deep generative neural networks (DGNNs). The synthesized data from three types of DGNNs (CTGAN, TVAE, and CopulaGAN) were based on seed data. For validation, 11 datasets were prepared: real data (original and seed), synthesized data (CTGAN, TVAE, and CopulaGAN), and augmented data (original + CTGAN, original + TVAE, original + CopulaGAN, seed + CTGAN, seed + TVAE, and seed + CopulaGAN). The large-sample-sized data, termed “original data”, served as the benchmark, whereas the small-sample-sized data acted as the foundation for synthesizing additional data. These datasets were evaluated using machine learning algorithms, particularly focusing on classification tasks. Conclusively, augmenting and synthesizing consumer survey data have shown potential in enhancing predictive performance, irrespective of the dataset’s size. Nonetheless, the challenge remains to minimize discrepancies between the original data and other datasets concerning the values and orders of feature importance. Although the efficacy of all three approaches should be improved in future work, CopulaGAN more accurately grasps the dependencies between the variables in table data compared with the other two DGNNs. The results provide cues for augmenting data with dependencies between variables in various fields.
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- 2024
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5. Allyl Isothiocyanate Maintains DHA-Containing Glycerophospholipids and Ameliorates the Cognitive Function Decline in OVX Mice
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Akika Nagata, Shiori Oishi, Nanako Kirishita, Keita Onoda, Takuma Kobayashi, Yuko Terada, Akira Minami, Nanami Senoo, Yasukiyo Yoshioka, Kunitoshi Uchida, Keisuke Ito, Shinji Miura, and Noriyuki Miyoshi
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Chemistry ,QD1-999 - Published
- 2023
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6. Cationic Gas-Permeable Mold Fabrication Using Sol–Gel Polymerization for Nano-Injection Molding
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Sayaka Miura, Rio Yamagishi, Mano Ando, Arisa Teramae, Yuna Hachikubo, Yoshiyuki Yokoyama, and Satoshi Takei
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sol–gel polymerization ,cationic gas-permeable mold ,injection molding ,nano-fabrication ,hydrophobic materials ,nano-structure ,Science ,Chemistry ,QD1-999 ,Inorganic chemistry ,QD146-197 ,General. Including alchemy ,QD1-65 - Abstract
Cationic gas-permeable molds fabricated via sol–gel polymerization undergo cationic polymerization using epoxide, resulting in gas permeability owing to their cross-linked structures. By applying this cationic gas-permeable mold to nano-injection molding, which is used for the mass production of resins, nano-protrusion structures with a height of approximately 300 nm and a pitch of approximately 400 nm were produced. The molding defects caused by gas entrapment in the air and cavities when using conventional gas-impermeable metal molds were improved, and the cationic gas-permeable mold could be continuously fabricated for 3000 shots under non-vacuum conditions. The results of the mechanical evaluations showed improved thermal stability and Martens hardness, which is expected to lead to the advanced production of resin nano-structures. Furthermore, the surface roughness of the nano-protrusion structures fabricated using injection molding improved the water contact angle by approximately 46°, contributing to the development of various hydrophobic materials in the future.
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- 2024
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7. Isoselenazole Synthesis by Rh-Catalyzed Direct Annulation of Benzimidates with Sodium Selenite
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Qing-Feng Xu-Xu, Yuji Nishii, and Masahiro Miura
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C–H bond cleavage ,direct coupling ,organoselenium compound ,annulation ,Chemistry ,QD1-999 - Abstract
Organoselenium compounds have attracted significant research interest because of their potent therapeutic activities and indispensable applications in the organic chemistry field. The selenation reactions conventionally rely on the use of sensitive Se reagents; thus, new synthetic methods with improved efficiency and operational simplicity have recently been of particular interest. In this manuscript, we report a Rh-catalyzed direct selenium annulation using tractable sodium selenite (Na2SeO3) as the limiting reagent. The selenite species was converted to highly electrophilic SeO(OBz)2 in situ upon treatment with Bz2O, thereby undergoing C–H/N–H double nucleophilic selenation. A series of benzimidates successfully underwent selenation under mild reaction conditions to afford isoselenazole derivatives.
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- 2023
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8. Theory of Chiral Electrodeposition by Micro-Nano-Vortexes under a Vertical Magnetic Field-2: Chiral Three-Dimensional (3D) Nucleation by Nano-Vortexes
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Ryoichi Morimoto, Miki Miura, Atsushi Sugiyama, Makoto Miura, Yoshinobu Oshikiri, Iwao Mogi, Yusuke Yamauchi, and Ryoichi Aogaki
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chirality ,chiral electrodeposition ,magnetic field ,nucleation ,micro-MHD vortex ,nano-MHD vortex ,Chemistry ,QD1-999 - Abstract
The contributions of magnetohydrodynamic (MHD) vortexes to chiral electrodeposition in a vertical magnetic field were theoretically examined based on the three-generation model of the 2D nucleus, 3D nucleus, and screw dislocation; for the vortexes to rotate in the second and third-generation, the kinematic viscosity must be at least 10−18 and 10−30 times lower than the ordinary value in the first generation, i.e., almost equal to zero. This implies that the ionic vacancy created on the electrode surface works as an atomic-scale lubricant. At the same time, the vortexes played three roles: promotion and suppression of nucleation, and transport of the chirality from the upper generation to the lower generation through precessional motion. Then, the rule of the chirality transfer was established, and finally, the relationship between the chiral activity and magnetic field was clarified in the presence and absence of chloride ions.
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- 2024
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9. Laser writing of preferentially orientated nitrogen-vacancy centers in diamond
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Kohei Kinouchi, Yasuhiko Shimotsuma, Mitsuharu Uemoto, Masanori Fujiwara, Norikazu Mizuochi, Masahiro Shimizu, and Kiyotaka Miura
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Femtosecond laser processing ,Polarization ,NV center ,Diamond ,First-principle calculation ,Chemistry ,QD1-999 - Abstract
Nitrogen-vacancy centers in diamond have gained widespread attention as quantum systems that can be applied in quantum information devices. The excellent properties of quantum devices can be enhanced using preferentially oriented nitrogen-vacancy (NV) centers. However, thus far, orientation control has been achieved only via chemical vapor deposition. In this study, we demonstrate the creation of preferentially oriented NV centers via laser writing. The alignment ratio of ensemble NV centers is biased along the direction parallel to [111], depending on the femtosecond laser polarization, causing an increase of 55 % in contrast to the optically magnetic resonance signal at maximum compared with 25 % in random orientation. Based on time-dependent density-functional theory (TDDFT) simulations and experimental observations, such complex polarization dependence can be attributed to the anisotropy of electron excitation. This technique provides a new optical fabrication method for engineered materials and devices used in quantum technology.
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- 2023
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10. Current situation and future perspectives for the use of fungi in the biomaterial industry and proposal for a new classification of fungal-derived materials
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Luz Alba Ballen Sierra, Thairine Mendes-Pereira, Glen Jasper Yupanqui García, Carla Queiroga Werkhaizer, Juliana B. de Rezende, Thiago Augusto Borges Rodrigues, Fernanda Badotti, Emanuelle Santos de Carvalho Cardoso, Andréa Miura da Costa, Ana Paula Uetanabaro, Maria Teresa Aguilar, and Aristóteles Góes-Neto
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Biological materials ,Fungi ,Mycelium ,Mycomaterials ,Bioindustry ,Materials of engineering and construction. Mechanics of materials ,TA401-492 ,Chemistry ,QD1-999 - Abstract
The potential applications of fungi in the development of new biomaterials derived from fungal mycelium have captured the attention from both the scientific community and the society. The notable ability of mycelium networks to self-construct and aggregate can be used to produce diverse biomaterials. These biomaterials can be created in a pure state, or both in conjunction with other organic/inorganic compounds. Recent advancements in mycomaterials have gained attention due to their sustainability and mechanical, thermogravimetric, and compression properties. Such properties contribute to reducing the reliance on environmentally problematic substrates within the industry. After a standardized and comprehensive review of publications on mycomaterials across different fields, such as biology, health, agriculture, engineering, and material sciences, we detected that publications on this theme are utterly scattered. This critical review enabled us to also propose a novel classification system for these fungal-derived materials to help to structure and standardize this emerging transdisciplinary field of knowledge.
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- 2023
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11. Fabrication Technology of Self-Dissolving Sodium Hyaluronate Gels Ultrafine Microneedles for Medical Applications with UV-Curing Gas-Permeable Mold
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Rio Yamagishi, Sayaka Miura, Kana Yabu, Mano Ando, Yuna Hachikubo, Yoshiyuki Yokoyama, Kaori Yasuda, and Satoshi Takei
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ultrafine microneedles ,sodium hyaluronate ,functional gels ,transdermal drug delivery system ,gas-permeable mold ,nanoimprint lithography ,Science ,Chemistry ,QD1-999 ,Inorganic chemistry ,QD146-197 ,General. Including alchemy ,QD1-65 - Abstract
Microneedles are of great interest in diverse fields, including cosmetics, drug delivery systems, chromatography, and biological sensing for disease diagnosis. Self-dissolving ultrafine microneedles of pure sodium hyaluronate hydrogels were fabricated using a UV-curing TiO2-SiO2 gas-permeable mold polymerized by sol-gel hydrolysis reactions in nanoimprint lithography processes under refrigeration at 5 °C, where thermal decomposition of microneedle components can be avoided. The moldability, strength, and dissolution behavior of sodium hyaluronate hydrogels with different molecular weights were compared to evaluate the suitability of ultrafine microneedles with a bottom diameter of 40 μm and a height of 80 μm. The appropriate molecular weight range and formulation of pure sodium hyaluronate hydrogels were found to control the dissolution behavior of self-dissolving ultrafine microneedles while maintaining the moldability and strength of the microneedles. This fabrication technology of ultrafine microneedles expands their possibilities as a next-generation technique for bioactive gels for controlling the blood levels of drugs and avoiding pain during administration.
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- 2024
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12. Enhanced Photocatalysis of Electrically Polarized Titania Nanosheets
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Tomoyuki Mihara, Kosuke Nozaki, Yasuyuki Kowaka, Mengtian Jiang, Kimihiro Yamashita, Hiroyuki Miura, and Satoshi Ohara
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TiO2 ,surface charge ,electrical polarization ,photocatalytic activity ,dye decolorization ,Chemistry ,QD1-999 - Abstract
Titania (TiO2) nanosheets are crystals with controlled, highly ordered structures that improve the functionality of conventional TiO2 nanoparticles. Various surface modification methods have been studied to enhance the effectiveness of these materials as photocatalysts. Surface modifications using electrical polarization have attracted considerable attention in recent years because they can improve the function of titania without changing its composition. However, the combination of facet engineering and electrical polarization has not been shown to improve the functionality of TiO2 nanosheets. In the present study, the dye-degradation performance of polarized TiO2 nanosheets was evaluated. TiO2 nanosheets with a F/Ti ratio of 0.3 were synthesized via a hydrothermal method. The crystal morphology and structure were evaluated using transmission electron microscopy and X-ray diffraction. Then, electrical polarization was performed under a DC electric field of 300 V at 300 °C. The polarized material was evaluated using thermally stimulated current measurements. A dye-degradation assay was performed using a methylene blue solution under ultraviolet irradiation. The polarized TiO2 nanosheets exhibited a dense surface charge and accelerated decolorization. These results indicate that electrical polarization can be used to enhance the photocatalytic activity of TiO2.
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- 2024
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13. Precise Purity Analysis of High-Purity Lanthanum Oxide by Gravimetric Analysis Assisted With Trace Elemental Analysis by Inductively Coupled Plasma Mass Spectrometry
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Tsutomu Miura and Ayaka Wada
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gravimetric analysis ,stoichiometry ,ICP-MS ,rare earth elements ,lanthanum ,traceability ,Chemistry ,QD1-999 - Abstract
Gravimetric analysis was used to determine the purity of high-purity La2O3 by stepwise conversions of the weighing forms. In this study, lanthanum in the sample was converted to La oxalate, La2O3, and La2(SO4)3 to evaluate the stoichiometry of the weighing forms for accurate gravimetric determination. The losses of La in the filtrate, the washing solution of the precipitate, and the mechanical loss of La during filtration were measured using inductively coupled plasma optical emission spectrometry. The weighing forms were evaluated by comparing the observed mass ratio with the theoretical value at each conversion step. The final converted La2(SO4)3 was consistent with the theoretical composition based on the observed mass ratio of La2(SO4)3/La2O3. Additionally, impurities in the high-purity La2O3 were determined by inductively coupled plasma tandem mass spectrometry. The purity of the original La2O3 sample was precisely determined to be 99.977 % ± 0.057% (mass fraction as La2O3; the value following “±” indicates the expanded uncertainty with a coverage factor k = 2.18) by a combination of the gravimetric analysis using the precipitation from the homogeneous solution method and verification of the weighing forms for La compound.
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- 2022
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14. Theory of Chiral Electrodeposition by Chiral Micro-Nano-Vortices under a Vertical Magnetic Field -1: 2D Nucleation by Micro-Vortices
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Ryoichi Morimoto, Miki Miura, Atsushi Sugiyama, Makoto Miura, Yoshinobu Oshikiri, Iwao Mogi, Yusuke Yamauchi, Satoshi Takagi, and Ryoichi Aogaki
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chirality ,chiral electrodeposition ,magnetic field ,nucleation ,micro-MHD vortex ,nano-MHD vortex ,Chemistry ,QD1-999 - Abstract
Remarkable chiral activity is donated to a copper deposit surface by magneto-electrodeposition, whose exact mechanism has been clarified by the three-generation model. In copper deposition under a vertical magnetic field, a macroscopic tornado-like rotation called the vertical magnetohydrodynamic (MHD) flow (VMHDF) emerges on a disk electrode, inducing the precessional motions of various chiral microscopic MHD vortices: First, chiral two-dimensional (2D) nuclei develop on an electrode by micro-MHD vortices. Then, chiral three-dimensional (3D) nuclei grow on a chiral 2D nucleus by chiral nano-MHD vortices. Finally, chiral screw dislocations are created on a chiral 3D nucleus by chiral ultra-micro MHD vortices. These three processes constitute nesting boxes, leading to a limiting enantiomeric excess (ee) ratio of 0.125. This means that almost all chiral activity of copper electrodes made by this method cannot exceed 0.125. It also became obvious that chirality inversion by chloride additive arises from the change from unstable to stable nucleation by the specific adsorption of it.
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- 2022
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15. Growth and Characterization of ROBiS2 High-Entropy Superconducting Single Crystals
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Yuma Fujita, Koki Kinami, Yuji Hanada, Masanori Nagao, Akira Miura, Shigeto Hirai, Yuki Maruyama, Satoshi Watauchi, Yoshihiko Takano, and Isao Tanaka
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Chemistry ,QD1-999 - Published
- 2020
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16. Magnetic Resonance Imaging as a Novel Method for Elucidating Sediment Burrow Structures and Functions
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Ayato Kohzu, Hidehiro Watanabe, Akio Imai, Nobuhiro Takaya, Shingo Miura, Koichi Shimotori, and Kazuhiro Komatsu
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Chemistry ,QD1-999 - Published
- 2020
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17. Synthesis of 2,3-Disubstituted 4‑Ethoxycarbonyl-β-carbolin-1-ones: Application to the Synthesis of SL651498 and Its Analogue
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Ryoya Miura, Shinsuke Goto, Takahide Hashimoto, and Iwao Hachiya
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Chemistry ,QD1-999 - Published
- 2020
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18. Fabrication of High-Resolution Fine Microneedles Derived from Hydrolyzed Hyaluronic Acid Gels in Vacuum Environment Imprinting Using Water Permeable Mold
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Sayaka Miura, Rio Yamagishi, Riku Miyazaki, Kaori Yasuda, Yuki Kawano, Yoshiyuki Yokoyama, Naoto Sugino, Takao Kameda, and Satoshi Takei
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fine microneedles ,hydrolyzed hyaluronic acid ,functional gels ,cosmetics ,transdermal drug delivery system ,water permeable mold ,Science ,Chemistry ,QD1-999 ,Inorganic chemistry ,QD146-197 ,General. Including alchemy ,QD1-65 - Abstract
Hydrolyzed hyaluronic acid high-resolution fine microneedles of 13 µm in diameter and 24 µm in height were fabricated from hydrolyzed hyaluronic acid gels made in mixtures of water using vacuum environment imprint lithography processes with a water permeable mold. The gas traps of water and volatile solvents in the imprint materials cause transfer failure in the conventional water impermeable molds of quartz and metal. However, the water permeable mold allows the use of 67 wt% dilution water with high solubility to increase the fluidity of the hydrolyzed hyaluronic acid during the patterning of high-resolution fine microneedles for cosmetics and pharmaceuticals. This demonstration sets a new paradigm of functional pure gels for high-resolution nano-patterning applications with various cosmetic and pharmaceutical materials containing dilution water using a water permeable mold.
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- 2022
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19. Screening of a Glycopolymer Library of GM1 Mimics Containing Hydrophobic Units Using Surface Plasmon Resonance Imaging
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Yuri Kimoto, Yuhei Terada, Yu Hoshino, and Yoshiko Miura
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Chemistry ,QD1-999 - Published
- 2019
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20. Activatable Photosensitizer for Targeted Ablation of lacZ-Positive Cells with Single-Cell Resolution
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Mayumi Chiba, Mako Kamiya, Kayoko Tsuda-Sakurai, Yuya Fujisawa, Hina Kosakamoto, Ryosuke Kojima, Masayuki Miura, and Yasuteru Urano
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Chemistry ,QD1-999 - Published
- 2019
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21. Convection‐Flow‐Assisted Preparation of a Strong Electron Dopant, Benzyl Viologen, for Surface‐Charge Transfer Doping of Molybdenum Disulfide
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Keigo Matsuyama, Akito Fukui, Kohei Miura, Hisashi Ichimiya, Yuki Aoki, Yuki Yamada, Prof. Atsushi Ashida, Prof. Takeshi Yoshimura, Prof. Norifumi Fujimura, and Prof. Daisuke Kiriya
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transition metal dichalcogenides ,benzyl viologen ,redox reactions ,molecular doping ,convection flow ,Chemistry ,QD1-999 - Abstract
Abstract Transition metal dichalcogenides (TMDCs) have received attention as atomically thin post‐silicon semiconducting materials. Tuning the carrier concentrations of the TMDCs is important, but their thin structure requires a non‐destructive modulation method. Recently, a surface‐charge transfer doping method was developed based on contacting molecules on TMDCs, and the method succeeded in achieving a large modulation of the electronic structures. The successful dopant is a neutral benzyl viologen (BV0); however, the problem remains of how to effectively prepare the BV0 molecules. A reduction process with NaBH4 in water has been proposed as a preparation method, but the NaBH4 simultaneously reacts vigorously with the water. Here, a simple method is developed, in which the reaction vial is placed on a hotplate and a fragment of air‐stable metal is used instead of NaBH4 to prepare the BV0 dopant molecules. The prepared BV0 molecules show a strong doping ability in terms of achieving a degenerate situation of a TMDC, MoS2. A key finding in this preparation method is that a convection flow in the vial effectively transports the produced BV0 to a collection solvent. This method is simple and safe and facilitates the tuning of the optoelectronic properties of nanomaterials by the easily‐handled dopant molecules.
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- 2019
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22. Catalysis of Cu Cluster for NO Reduction by CO: Theoretical Insight into the Reaction Mechanism
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Nozomi Takagi, Kazuya Ishimura, Hiroki Miura, Tetsuya Shishido, Ryoichi Fukuda, Masahiro Ehara, and Shigeyoshi Sakaki
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Chemistry ,QD1-999 - Published
- 2019
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23. Effects of functional polysaccharide from silkworm as an immunostimulant on transcriptional profiling and disease resistance in fish
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Takeshi Miura, M.F.Z. Ali, S. Nakahara, A. Ido, Chiemi Miura, and Y. Otsu
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chemistry.chemical_classification ,medicine.drug_class ,fungi ,RNA-Seq ,Fish health ,Plant disease resistance ,Biology ,Polysaccharide ,Immunostimulant ,Microbiology ,Immune system ,chemistry ,Insect Science ,medicine ,%22">Fish ,Food Science - Abstract
Dietary manipulation to maintain fish health and reduce bacterial infection through the use of immunostimulants has been widely used worldwide. A broad range of bioactive substances capable of optimising animal health has been found in several insect species, including antimicrobial/antiviral peptides, polysaccharides such as chitin, lauric acid, and insect products such as honey. Recently, we identified a novel bioactive polysaccharide from Bombyx mori, termed silkrose-BM, that can activate innate immunity in mammalian RAW264.7 macrophages and provide effective protection against vibriosis in penaeid prawns. However, the efficacy of dietary silkrose-BM in teleosts remains unclear. Here, we investigated the effects of dietary inclusion of silkrose-BM in Japanese medaka (Oryzias latipes) after they were artificially challenged with Edwardsiella tarda. The survival of medaka after infection with E. tarda was significantly improved by dietary silkrose-BM at a concentration of 10, 100, and 1000 ng/g. RNA-seq analysis was performed in the intestine and liver of the medaka to identify changes in the transcriptional profiling evoked by silkrose-BM. The dietary silkrose-BM group showed 1,194 and 2,259 differentially expressed genes (DEGs) in the intestine and liver, respectively, when compared with the control group prior to E. tarda infection. Functional enrichment analysis of DEGs showed several putative genes involved in the Toll-like receptor/nuclear factor κB pathway, cytokine-cytokine receptor interactions, complement cascade, antimicrobial peptides, and junctional modification. Taken together, these results suggest that silkrose-BM used as an immunostimulant can improve the immune system and resistance to edwardsiellosis in teleosts.
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- 2022
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24. Flux Growth and Superconducting Properties of (Ce,Pr)OBiS2 Single Crystals
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Masanori Nagao, Akira Miura, Daisuke Urushihara, Yuki Maruyama, Yosuke Goto, Yoshikazu Mizuguchi, Chikako Moriyoshi, Yoshihiro Kuroiwa, Yongming Wang, Satoshi Watauchi, Toru Asaka, Yoshihiko Takano, Kiyoharu Tadanaga, and Isao Tanaka
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BiS2 superconductor ,flux growth ,TEM ,single crystals ,XAFS ,Chemistry ,QD1-999 - Abstract
Ce1−xPrxOBiS2 (0. 1 ≤ x ≤ 0.9) single crystals were grown using a CsCl flux method. Their structural and physical properties were examined by X-ray diffraction, X-ray absorption, transmission electron microscopy, and electrical resistivity. All of the Ce1−xPrxOBiS2 single crystals with 0.1 ≤ x ≤ 0.9 exhibited tetragonal phase. With increasing Pr content, the a-axis and c-axis lattice parameters decreased and increased, respectively. Transmission electron microscope analysis of Ce0.1Pr0.9OBiS2 (x = 0.9) single crystal showed no stacking faults. Atomic-resolution energy dispersive X-ray spectrometry mapping revealed that Bi, Ce/Pr, O, and S occupied different crystallographic sites, while Ce and Pr randomly occupied the same sites. X-ray absorption spectra showed that an increase of the Pr ratio increased the ratio of Ce4+/Ce3+. All of the Ce1−xPrxOBiS2 crystals showed superconducting transition, with a maximum transition temperature of ~4 K at x = 0.9.
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- 2020
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25. Aerosol–Cloud Interaction at the Summit of Mt. Fuji, Japan: Factors Influencing Cloud Droplet Number Concentrations
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Yoko Iwamoto, Ayami Watanabe, Ryota Kataoka, Mitsuo Uematsu, and Kazuhiko Miura
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cloud condensation nuclei ,high alpine site ,size distribution ,hygroscopicity parameter ,water vapor supersaturation ,Technology ,Engineering (General). Civil engineering (General) ,TA1-2040 ,Biology (General) ,QH301-705.5 ,Physics ,QC1-999 ,Chemistry ,QD1-999 - Abstract
To investigate interactions between aerosols and clouds, the size and number concentrations of the cloud condensation nuclei (CCN) and the cloud droplets (CDs) were measured at the summit of Mt. Fuji (altitude 3776 m), Japan. The CCN number concentrations (NCCN) are significantly higher in continental air masses than in air masses from the Pacific Ocean. The hygroscopicity parameter κ did not change much for different air mass origins, indicating that aerosol particles in the free troposphere are well mixed. Based on the CD number concentrations (NCD), the degree of supersaturation in the ambient air during the cloud-shrouded period was estimated to be 0.15% (25th percentile) to 0.44% (75th percentile). To evaluate factors influencing the NCD, measured NCD were compared to ones calculated based on the Köhler theory using aerosol number size distributions, κ, and the degree of supersaturation. The results showed that NCD could not be reproduced satisfyingly when the mean number size distribution or the mean effective supersaturation were used for the calculation. This study highlights the importance of obtaining information about the degree of supersaturation to predict NCD in the atmosphere.
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- 2021
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26. Development of an Automatic Ultrasound Image Classification System for Pressure Injury Based on Deep Learning
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Masaru Matsumoto, Mikihiko Karube, Gojiro Nakagami, Aya Kitamura, Nao Tamai, Yuka Miura, Atsuo Kawamoto, Masakazu Kurita, Tomomi Miyake, Chieko Hayashi, Akiko Kawasaki, and Hiromi Sanada
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ultrasonography ,pressure injury ,automatic classification system ,deep learning ,Technology ,Engineering (General). Civil engineering (General) ,TA1-2040 ,Biology (General) ,QH301-705.5 ,Physics ,QC1-999 ,Chemistry ,QD1-999 - Abstract
The classification of ultrasound (US) findings of pressure injury is important to select the appropriate treatment and care based on the state of the deep tissue, but it depends on the operator’s skill in image interpretation. Therefore, US for pressure injury is a procedure that can only be performed by a limited number of highly trained medical professionals. This study aimed to develop an automatic US image classification system for pressure injury based on deep learning that can be used by non-specialists who do not have a high skill in image interpretation. A total 787 training data were collected at two hospitals in Japan. The US images of pressure injuries were assessed using the deep learning-based classification tool according to the following visual evidence: unclear layer structure, cobblestone-like pattern, cloud-like pattern, and anechoic pattern. Thereafter, accuracy was assessed using two parameters: detection performance, and the value of the intersection over union (IoU) and DICE score. A total of 73 images were analyzed as test data. Of all 73 images with an unclear layer structure, 7 showed a cobblestone-like pattern, 14 showed a cloud-like pattern, and 15 showed an anechoic area. All four US findings showed a detection performance of 71.4–100%, with a mean value of 0.38–0.80 for IoU and 0.51–0.89 for the DICE score. The results show that US findings and deep learning-based classification can be used to detect deep tissue pressure injuries.
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- 2021
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27. Macroporous Gel with a Permeable Reaction Platform for Catalytic Flow Synthesis
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Hikaru Matsumoto, Hirokazu Seto, Takanori Akiyoshi, Makoto Shibuya, Yu Hoshino, and Yoshiko Miura
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Chemistry ,QD1-999 - Published
- 2017
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28. Concerted Functions of Surface Acid–Base Pairs and Supported Copper Catalysts for Dehydrogenative Synthesis of Esters from Primary Alcohols
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Hiroki Miura, Karin Nakahara, Takahiro Kitajima, and Tetsuya Shishido
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Chemistry ,QD1-999 - Published
- 2017
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29. Prediction of Ternary Liquidus Temperatures by Statistical Modeling of Binary and Ternary Ag–Al–Sn–Zn Systems
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Akira Miura, Tsukasa Hokimoto, Masanori Nagao, Takashi Yanase, Toshihiro Shimada, and Kiyoharu Tadanaga
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Chemistry ,QD1-999 - Published
- 2017
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30. Development of Highly Sensitive Strain Sensor Using Area-Arrayed Graphene Nanoribbons
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Ken Suzuki, Ryohei Nakagawa, Qinqiang Zhang, and Hideo Miura
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graphene nanoribbon ,piezoresistivity ,strain sensor ,Chemistry ,QD1-999 - Abstract
In this study, a basic design of area-arrayed graphene nanoribbon (GNR) strain sensors was proposed to realize the next generation of strain sensors. To fabricate the area-arrayed GNRs, a top-down approach was employed, in which GNRs were cut out from a large graphene sheet using an electron beam lithography technique. GNRs with widths of 400 nm, 300 nm, 200 nm, and 50 nm were fabricated, and their current-voltage characteristics were evaluated. The current values of GNRs with widths of 200 nm and above increased linearly with increasing applied voltage, indicating that these GNRs were metallic conductors and a good ohmic junction was formed between graphene and the electrode. There were two types of GNRs with a width of 50 nm, one with a linear current–voltage relationship and the other with a nonlinear one. We evaluated the strain sensitivity of the 50 nm GNR exhibiting metallic conduction by applying a four-point bending test, and found that the gauge factor of this GNR was about 50. Thus, GNRs with a width of about 50 nm can be used to realize a highly sensitive strain sensor.
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- 2021
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31. Ultrahigh-Pressure Preparation and Catalytic Activity of MOF-Derived Cu Nanoparticles
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Ichiro Yamane, Kota Sato, Ryoichi Otomo, Takashi Yanase, Akira Miura, Taro Nagahama, Yuichi Kamiya, and Toshihiro Shimada
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metal–organic framework (MOF) ,catalysis ,copper nanoparticles ,ultrahigh pressure ,Huisgen cycloaddition ,Chemistry ,QD1-999 - Abstract
A metal–organic framework (MOF) consisting of Cu-benzenetricarboxylic acid was processed under ultrahigh pressure (5 GPa) and at temperature of up to 500 °C. The products were characterized with TEM, FTIR, and XAFS. The decomposition of the MOF started at 200 °C at 5 GPa. This temperature was much lower than that in the vacuum. Single-nanometer Cu nanoparticles were obtained in carbon matrix, which was significantly smaller than the Cu particles prepared at ambient pressure. The catalytic activity for Huisgen cycloaddition was examined, and the sample processed at 5 GPa showed a much improved performance compared with that of the MOF-derived Cu nanoparticles prepared without high pressure.
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- 2021
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32. Associations Between Plasma Concentrations of Lenvatinib and Angiopoietin and Clinical Responses to Lenvatinib Therapy in Japanese Patients With Thyroid Cancer
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Kiminori Sugino, Yumiko Akamine, Mitsuji Nagahama, Tomoko Ozeki, Koichi Ito, Maho Kumagai, Masatomo Miura, and Akifumi Suzuki
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Oncology ,medicine.medical_specialty ,business.industry ,medicine.disease ,Angiopoietin ,chemistry.chemical_compound ,chemistry ,Internal medicine ,Plasma concentration ,cardiovascular system ,Medicine ,business ,Lenvatinib ,Thyroid cancer ,hormones, hormone substitutes, and hormone antagonists ,Research Article - Abstract
Purpose: The purpose of this study was to investigate the relationships among plasma concentrations of lenvatinib, angiopoietin (Ang)-1 and Ang-2, and clinical responses to lenvatinib therapy in Japanese patients with thyroid cancer. Methods: Plasma concentrations of lenvatinib (C0) and Ang-1 and -2 were measured by HPLC and ELISA, respectively.Results: The median change rates of Ang-1 and Ang-2 at 1 month after treatment from baseline in 36 patients were -15.3% and -48.4%, respectively. However, the change of Ang-1 and Ang-2 at 1 month from baseline did not correlate with lenvatinib C0. In patients with partial response (PR) and stable disease to lenvatinib, Ang-2 at 1 month were significantly lower than Ang-2 at baseline (P < 0.001 and P < 0.05, respectively), but were not significantly lower in patients with progressive disease. The area under the ROC for PR prediction was 0.667, giving the best sensitivity (69.2%) and specificity (73.9%) at a threshold of the change rate of Ang-2 of -49.83%. A one year overall survival for patients having the change rate of Ang-2 of at least -49.83% and less than -49.83% were 62.5% and 40%, respectively. In patients who continued treatment with lenvatinib for 1 year, Ang-2 at 1 month and 1 year after treatment were significantly lower than those at baseline (each P < 0.001).Conclusion: The change of Ang-2 at 1 month after treatment from baseline rather than simply the Ang-2 level at baseline may be important as a biomarker of the inhibitory effect of angiogenesis by lenvatinib.
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- 2022
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33. PEGylation of silver nanoparticles by physisorption of cyclic poly(ethylene glycol) for enhanced dispersion stability, antimicrobial activity, and cytotoxicity
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Yutaka Miura, Manabu Tokeshi, Kenji Tajima, Shin-ichiro Sato, Shuya Uno, Yubo Wang, Onyinyechukwu Oziri, Toshifumi Satoh, Takuya Isono, Takuya Yamamoto, Masatoshi Maeki, and Tomohisa Watanabe
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Nanostructure ,Chemistry ,technology, industry, and agriculture ,General Engineering ,Bioengineering ,macromolecular substances ,General Chemistry ,Atomic and Molecular Physics, and Optics ,Silver nanoparticle ,Physisorption ,Chemical engineering ,Colloidal gold ,Dispersion stability ,PEG ratio ,PEGylation ,General Materials Science ,Cytotoxicity - Abstract
Silver nanoparticles (AgNPs) are practically valuable in biological applications. However, no steady PEGylation has been established, which is essential for internal use in humans or animals. In this study, cyclic PEG (c-PEG) without any chemical inhomogeneity is physisorbed onto AgNPs to successfully PEGylate and drastically enhance the dispersion stability against physiological conditions, white light, and high temperature. In contrast, linear HO-PEG-OH and MeO-PEG-OMe do not confer stability to AgNPs, and HS-PEG-OMe, which is often used for gold nanoparticles, sulfidates the surface to considerably degrade the properties. TEM shows an essentially intact nanostructure of c-PEG-physisorbed AgNPs even after heating at 95 degrees C, while complete disturbance is observed for other AgNPs. Molecular weight- and concentration-dependent stabilization by c-PEG is investigated, and DLS and zeta-potential measurements prove the formation of a c-PEG layer on the surface of AgNPs. Furthermore, c-PEG-physisorbed AgNPs exhibit persistent antimicrobial activity and cytotoxicity.
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- 2022
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34. Investigation of the effect of microflow reactor diameter on condensation reactions in <scp>l</scp>-proline-immobilized polymer monoliths
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Seiya Nonaka, Yu Hoshino, Yoshiko Miura, Masanori Nagao, and Hikaru Matsumoto
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Fluid Flow and Transfer Processes ,chemistry.chemical_classification ,chemistry ,Chemical engineering ,Chemistry (miscellaneous) ,Process Chemistry and Technology ,Chemical Engineering (miscellaneous) ,Polymer ,Proline ,Condensation reaction ,Catalysis - Abstract
Structure of porous monolith in a microflow reactor and the reactor diameter affect the residence time distribution (RTD). The effect of the RTD on the catalytic efficiency of the asymmetric aldol addition reaction was examined.
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- 2022
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35. Regorafenib is suitable for advanced colorectal cancer patients who have previously received trifluridine/tipiracil plus bevacizumab
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T. Ikoma, Toshihiko Matsumoto, Masahiro Takatani, Shogo Yamamura, Takao Tsuduki, Hiroki Nagai, Kou Miura, Hisateru Yasui, and Takanori Watanabe
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Oncology ,Advanced colorectal cancer ,chemistry.chemical_compound ,medicine.medical_specialty ,Multidisciplinary ,Bevacizumab ,chemistry ,business.industry ,Regorafenib ,Internal medicine ,medicine ,business ,medicine.drug - Abstract
Background: Regorafenib is a standard salvage line therapy used for advanced colorectal cancer (CRC). Recently, FTD/TPI plus bevacizumab also showed promising efficacy as a salvage line therapy for advanced CRC. However, the efficacy and safety of regorafenib for patients with advanced CRC who have previously received trifluridine/tipiracil (TFTD) plus bevacizumab is unclear.Results: We retrospectively collected clinicopathologic data from patients with advanced CRC who received regorafenib after TFTD plus bevacizumab in multiple institutions between April 2017 and June 2020.Thirty-four advanced CRC patients who received regorafenib were analyzed. The median age was 66.5 (range 43−81 years), 11 patients were male, and all had an ECOG performance status(PS) of 0 or 1. Twenty-two patients had left-sided tumors, 18 patients had RAS mutants, and 1 patient had a BRAF V600E mutation. The response rate was 0%, and the disease control rate was 31%. The median progression-free survival was 70 days (95% CI: 56−91), and the overall survival was 233 days (95% CI: 188−324). Treatment was discontinued in 32 patients, and 28 (82%) discontinued treatment due to progressive disease. The major grade 3 and4 toxicities were proteinurea (29%), hypertension (26%), hand-foot syndrome(15%), and platelet decrease (6%).Conclusion: Regorafenib after TFTD plus bevacizumab showed efficacy similar to that of the previous study, and no new adverse events were observed.
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- 2023
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36. Ecological risk assessment of Piper aduncum essential oil in non-target organisms
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Claudio Martin Jonsson, Edsandra Campos Chagas, Patrícia Tidori Miura, Sonia C. N. Queiroz, Felix Guillermo Reyes Reyes, Francisco Célio Maia Chaves, PATRÍCIA TIDORI MIURA, Universidade Estadual de Campinas, CLAUDIO MARTIN JONSSON, CNPMA, SONIA CLAUDIA DO N DE QUEIROZ, CNPMA, EDSANDRA CAMPOS CHAGAS, CPAA, FRANCISCO CELIO MAIA CHAVES, CPAA, and FELIX GUILLERMO REYES REYES, Universidade Estadual de Campinas.
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Science (General) ,Óleo Essencial ,Fish farming ,concentração previsível sem efeito ,predicted no-effect concentration ,spiked pepper ,Ecotoxicology ,law.invention ,Toxicology ,03 medical and health sciences ,chemistry.chemical_compound ,Q1-390 ,Non target ,law ,Ecotoxicidade ,Predicted no-effect concentration ,distribuição da sensibilidade das espécies ,Essential oil ,species sensitivity distribution ,030304 developmental biology ,Piscicultura ,Dillapiole ,hazardous concentration (5%) ,0303 health sciences ,Piper aduncum ,biology ,ecotoxicity ,Nontarget organisms ,04 agricultural and veterinary sciences ,biology.organism_classification ,concentração perigosa (5%) ,chemistry ,pimenta-de-macaco ,Essential oils ,040102 fisheries ,Toxidez ,0401 agriculture, forestry, and fisheries ,Environmental science ,Gas chromatography ,Ecotoxicity ,General Agricultural and Biological Sciences - Abstract
One possible alternative to chemotherapeutic agents in the treatment and prevention of diseases in fish farms is the use of Piper aduncum essential oil. However, ecotoxicological data are required to ensure its proper use and to prevent adverse effects on non-target organisms. These data are relevant since this essential oil is described as having insecticidal, molluscicidal and cytotoxic activitiy that may be associated with its chemical composition. Thus, the aim of this study was to evaluate the ecotoxicity of P. aduncum essential oil to five test organisms using the species sensitivity distribution (SSD) statistical approach. The chemical composition of the essential oil was characterized by means of gas chromatography coupled to mass spectrometry (GC-MS) and gas chromatography-flame ionization detection (GC-FID) for identification and quantitation purposes, respectively. The main component (75.5%) of the essential oil was dillapiole. The hazardous concentration for 5% of biological species (HC5) was calculated to determine the 95% protection level, resulting in a value of 0.47 mg L-1 (with a confidence interval of 0.028 - 1.19 mg L-1. ). A concentration range related to the level of protection for aquatic communities (the predicted no-effect concentration, PNEC) was determined through the application of safety factors to the HC5 value. The ecotoxicity parameters showed that P. aduncum essential oil can be used safely in water bodies at a concentration equal to or below 0.09 mg L-1. RESUMO Uma possível alternativa ao uso de fármacos veterinários no tratamento e prevenção de doenças na piscicultura é o uso do óleo essencial de Piper aduncum. No entanto, são necessários dados ecotoxicológicos para garantir seu uso apropriado sem causar efeitos adversos a organismos não alvo. Esta informação é relevante, pois esse óleo essencial é descrito como tendo atividades inseticidas, moluscicidas e citotóxicas, possivelmente associadas à sua composição química. Assim, o objetivo deste estudo foi avaliar a ecotoxicidade do óleo essencial de P. aduncum para cinco organismos-teste, usando o método estatístico da Distribuição da Sensibilidade das Espécies (SSD). A composição química do óleo essencial foi caracterizada por cromatografia gasosa acoplada a espectrometria de massa (GC-MS) e cromatografia gasosa com detector de ionização de chama (GC-FID), para fins de identificação e quantificação, respectivamente. O principal componente (75,5%) do óleo essencial foi o dilapiol. A concentração perigosa para 5% de espécies biológicas (HC5) foi calculada com um nível de proteção de 95%, resultando em um valor de 0,47 mg L-1 (com intervalo de confiança de 50% = 0,028 - 1,19 mg L-1). A faixa de concentração relacionada aos níveis de proteção para comunidades aquáticas (concentração sem efeito previsto - PNEC) foi calculada através da aplicação de fatores de segurança ao valor de HC5. Os parâmetros de ecotoxicidade indicaram que o óleo essencial de P. aduncum pode ser usado com segurança em corpos d’água se a concentração for igual ou inferior a 0,09 mg L-1.
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- 2021
37. Steric and Electronic Effects on Thermal Stability of Nitrile N-Oxide: a Case Study of Naphthalen-2-ol Derived Substrates
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Souma Ooba, Masahiro Hamada, Shiho Bando, Toshikazu Takata, Noriyuki Nakajima, Kaori Miura, and Yasuhito Koyama
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Steric effects ,chemistry.chemical_compound ,Nitrile ,chemistry ,Polymer chemistry ,Oxide ,Electronic effect ,Thermal stability ,General Chemistry ,Isomerization ,Isocyanate - Abstract
This paper describes the syntheses of four types of nitrile N-oxides (NOs) and studies on the thermal isomerization of NOs to isocyanates (Isocs). It is found that a bulky electron-withdrawing subs...
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- 2021
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38. Preparation of Cu3N thin films by nitridation of solution process-derived thin films using urea
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Yuki Ohigashi, Amon Higuchi, Nataly Carolina Rosero-Navarro, Kiyoharu Tadanaga, and Akira Miura
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Biomaterials ,chemistry.chemical_compound ,Materials science ,chemistry ,Chemical engineering ,Materials Chemistry ,Ceramics and Composites ,Urea ,General Chemistry ,Thin film ,Condensed Matter Physics ,Solution process ,Electronic, Optical and Magnetic Materials - Published
- 2021
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39. Quantitative Analysis of Nitrogen by Atom Probe Tomography Using Stoichiometric γ′-Fe4N Consisting of 15N Isotope
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Kazuto Kawakami, Mitsuhiro Hirano, Koyo Miura, Jun Takahashi, and Naofumi Ohtsu
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Nitrogen deficiency ,Analytical chemistry ,chemistry.chemical_element ,Atom probe ,Nitrogen ,Isotopes of nitrogen ,law.invention ,Ion ,Iron nitride ,chemistry.chemical_compound ,chemistry ,law ,Atom ,Kinetic isotope effect ,Instrumentation - Abstract
The nitrogen deficiency in steels measured by atom probe tomography (APT) is considered to arise from the obscurement of singly charged dimer nitrogen ions (N2+) by the iron-dominant peak (56Fe2+) at 28 Da. To verify this by quantifying the amount of N2+ ions, γ′-Fe4N consisting of the 15N isotope was prepared on iron substrates by plasma nitriding using a nitrogen isotopic gas (15N2). Although considerable amounts of 15N2+ were observed at 30 Da without overlap with any iron peak, the observed nitrogen concentrations of γ′-Fe4N were clearly lower than the stoichiometric composition (19–20 at%), using both pulsed voltage and pulsed laser atom probes. The origin of the missing nitrogen, excluding nitrogen obscured by other ion species, was predicted to be the occurrence of neutral nitrogen or nitrogen gas molecules in field evaporation. The generation rate of iron nitride ions (FeN2+) for 15N was significantly lower than that for 14N in γ′-Fe4N, which affected the amount of the missing nitrogen. The isotope effect suggests that the isotopic ratio cannot always be determined from only one ion species among the multiple species observed in the APT analysis. We discuss the mechanism of the isotope effect in FeN2+ formation by field evaporation.
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- 2021
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40. Regioselective Synthesis of Trisubstituted Quinoxalines Mediated by Hypervalent Iodine Reagents
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Kasumi Miura, Noriyuki Suzuki, Ren Takehara, Ryota Ito, and Yumiko Suzuki
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Annulation ,Organic Chemistry ,Hypervalent molecule ,Regioselectivity ,chemistry.chemical_element ,Iodides ,Iodine ,Combinatorial chemistry ,Catalysis ,chemistry.chemical_compound ,chemistry ,Quinoxalines ,Reagent ,Indicators and Reagents ,Prospective Studies ,Benzene - Abstract
A facile and regioselective synthesis of quinoxalines, an important motif in medicinal chemistry and materials sciences, was developed. Despite their prospective utility, the regioselective preparation of trisubstituted quinoxalines has not been previously established. In the reported system, hypervalent iodine reagents catalyzed the annulation between α-iminoethanones and o-phenylenediamines in a chemo/regioselective manner to afford trisubstituted quinoxalines. Excellent regioselectivities (6:1 to 1:0) were achieved using [bis(trifluoroacetoxy)iodo]benzene and [bis(trifluoroacetoxy)iodo]pentafluorobenzene as annulation catalysts.
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- 2021
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41. Lack of inhibitory effect of wood creosote on cytochrome <scp>P450‐mediated</scp> drug metabolism
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Mariko Iwase, Takashi Shibata, Masafumi Ito, Yuki Nishimura, Mutsumi Asai, Mayumi Tsuji, Koichiro Shinya, Takanori Miura, Yuji Kiuchi, Norimitsu Kurata, Hirofumi Morino, and Hirokazu Chokki
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Wood creosote ,biology ,Chemistry ,biology.protein ,Cytochrome P450 ,General Medicine ,Pharmacology ,Inhibitory effect ,Drug metabolism - Published
- 2021
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42. The Impact of Cataract Surgery on Contrast Visual Acuity and Retinal Sensitivity in Patients with Retinitis Pigmentosa
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Tomoaki Tatsumi, Shuichi Yamamoto, Gen Miura, Hirotaka Yokouchi, and Takayuki Baba
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medicine.medical_specialty ,Visual acuity ,Article Subject ,genetic structures ,Mesopic vision ,medicine.medical_treatment ,media_common.quotation_subject ,chemistry.chemical_compound ,Ophthalmology ,Retinitis pigmentosa ,medicine ,Contrast (vision) ,media_common ,business.industry ,Retinal ,RE1-994 ,Cataract surgery ,medicine.disease ,eye diseases ,chemistry ,sense organs ,medicine.symptom ,business ,Microperimetry ,Research Article ,Photopic vision - Abstract
Purpose. To determine the effects of cataract surgery on contrast visual acuity and retinal sensitivity in patients with retinitis pigmentosa. Methods. Retinal sensitivity and contrast visual acuity were determined by microperimetry (MAIA) and contrast sensitivity acuity tester (CAT-CP), respectively, before and after cataract surgery. The significance of the correlations between visual acuity, retinal sensitivity, contrast visual acuity, improvements after surgery, and macular structure before and after cataract surgery was determined. Results. Retinal sensitivity and contrast visual acuity were significantly improved after cataract surgery. The correlations among postoperative visual acuity, postoperative retinal sensitivities, and preoperative ellipsoid zone length were significant. The postoperative retinal sensitivity of the central 10° and the ellipsoid zone length was particularly significantly correlated. Preoperative contrast visual acuity and the amount of improvement and preoperative retinal sensitivity and the amount of improvement were significantly negatively correlated. The contrast visual acuity under both the 100% and 10% photopic and mesopic conditions improved significantly after cataract surgery. Conclusions. Cataract surgery in retinitis pigmentosa patients with preserved ellipsoid zones significantly improved retinal sensitivity and contrast visual acuity. Cataract surgery can be expected to improve retinal sensitivity and contrast visual acuity under various conditions, even if preoperative visual parameters are low, as long as the ellipsoid zone is preserved.
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- 2021
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43. Synthesis of Benzoisoselenazolones via Rh(III)‐Catalyzed Direct Annulative Selenation by Using Elemental Selenium
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Hidehiro Sakurai, Yuji Nishii, Qing-Feng Xu-Xu, Yuta Uetake, and Masahiro Miura
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Reaction conditions ,Cyclodextrins ,Reaction mechanism ,Annulation ,Absorption spectroscopy ,Organic Chemistry ,chemistry.chemical_element ,General Chemistry ,Combinatorial chemistry ,Catalysis ,Selenium ,chemistry.chemical_compound ,chemistry ,Electrophile ,Organic synthesis - Abstract
Isoselenazolone derivatives have attracted significant research interest because of their potent therapeutic activities and indispensable applications in organic synthesis. Efficient construction of functionalized isoselenazolone scaffolds is still challenging, and thus new synthetic approaches with improved operational simplicity have been of particular interest. In this manuscript, we introduce a rhodium-catalyzed direct selenium annulation by using stable and tractable elemental selenium. A series of benzamides as well as acrylamides were successfully coupled with selenium under mild reaction conditions, and the obtained isoselenazolones could be pivotal synthetic precursors for several organoselenium compounds. Based on the designed control experiments and X-ray absorption spectroscopy measurements, we propose an unprecedented selenation mechanism involving a highly electrophilic Se(IV) species as the reactive selenium donor. The reaction mechanism was further verified by a computational study.
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- 2021
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44. Differences in Pharmacokinetics and Haematotoxicities of Aniline and Its Dimethyl Derivatives Orally Administered in Rats
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Yusuke Kamiya, Makiko Shimizu, Norie Murayama, Tomonori Miura, and Hiroshi Yamazaki
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Male ,Pharmacology ,Aniline Compounds ,Chromatography ,Hemolytic Agents ,Chemistry ,Administration, Oral ,Pharmaceutical Science ,General Medicine ,Hydroxylation ,Positive correlation ,Mass spectrometry ,Rats, Sprague-Dawley ,chemistry.chemical_compound ,Aniline ,Pharmacokinetics ,Acetylation ,Area Under Curve ,Plasma concentration ,Animals ,Methyl group ,N hydroxylation - Abstract
Aniline and its dimethyl derivatives reportedly become haematotoxic after metabolic N-hydroxylation of their amino groups. The plasma concentrations of aniline and its dimethyl derivatives after single oral doses of 25 mg/kg in rats were quantitatively measured and semi-quantitatively estimated using liquid chromatography-tandem mass spectrometry. The quantitatively determined elimination rates of aniline; 2,4-dimethylaniline; and 3,5-dimethylaniline based on rat plasma versus time curves were generally rapid compared with those of 2,3-; 2,5-; 2,6-; and N,2-dimethylaniline. The primary acetylated metabolites of aniline; 2,4-dimethylaniline; and 3,5-dimethylaniline, as semi-quantitatively estimated based on their peak areas in liquid chromatography analyses, were more extensively formed than those of 2,3-; 2,5-; 2,6-; and N,2-dimethylaniline. The areas under the curve of unmetabolized (remaining) aniline and its dimethyl derivatives estimated using simplified physiologically based pharmacokinetic models (that were set up using the experimental plasma concentrations) showed an apparently positive correlation with the reported lowest-observed-effect levels for haematotoxicity of these chemicals. In the case of 2,4-dimethylaniline, a methyl group at another C4-positon would be one of the determinant factors for rapid metabolic elimination to form aminotoluic acid. These results suggest that rapid and extensive metabolic activation of aniline and its dimethyl derivatives occurred in rats and that the presence of a methyl group at the C2-positon may generally suppress fast metabolic rates of dimethyl aniline derivatives that promote metabolic activation reactions at NH2 moieties.
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- 2021
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45. Sodium bicarbonate ingestion mitigates the heat-induced hyperventilation and reduction in cerebral blood velocity during exercise in the heat
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Yoshiyuki Fukuba, Akira Katagiri, Takeshi Nishiyasu, Naoto Fujii, Bun Tsuji, Yasuhiko Kitadai, and Akira Miura
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Male ,Hyperthermia ,medicine.medical_specialty ,Hot Temperature ,Blood velocity ,Physiology ,Metabolic alkalosis ,Eating ,chemistry.chemical_compound ,Hypocapnia ,Physiology (medical) ,Internal medicine ,Hyperventilation ,medicine ,Humans ,Ingestion ,Exercise ,Sodium bicarbonate ,business.industry ,medicine.disease ,Sodium Bicarbonate ,Cerebral blood flow ,chemistry ,Cardiology ,medicine.symptom ,business - Abstract
Hyperthermia causes hyperventilation and concomitant hypocapnia and cerebral hypoperfusion. The cerebral hypoperfusion may underlie central fatigue. We demonstrate that sodium bicarbonate ingestion reduces heat-induced hyperventilation and attenuates hypocapnia-related cerebral hypoperfusion during prolonged exercise in the heat. In addition, we show that sodium bicarbonate ingestion reduces ratings of perceived exertion during the exercise. This study provides new insight into the development of an effective strategy for preventing central fatigue during exercise in the heat.
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- 2021
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46. Approximate local isometries of derivative Hardy spaces
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Takeshi Miura and A. Jiménez-Vargas
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chemistry.chemical_compound ,symbols.namesake ,Pure mathematics ,Mathematics (miscellaneous) ,Algebraic re exivity, topological re exivity, isometry group, isometric reflection ,chemistry ,symbols ,Hardy space ,Derivative (chemistry) ,Mathematics - Abstract
For any 1 ≤ p ≤ ∞, let Sp (ⅅ) be the space of holomorphic functions ƒ on ⅅ such that ƒ′ belongs to the Hardy space Hp(ⅅ), with the norm ∥ƒ∥∑ = ∥f∥∞+∥ƒ′∥p. We prove that every approximate local isometry of Sp(ⅅ) is a surjective isometry and that every approximate 2-local isometry of Sp(ⅅ) is a surjective linear isometry. As a consequence, we deduce that the sets of isometric re ections and generalized bi-circular projections on Sp(ⅅ) are also topologically re exive and 2-topologically reflexive.
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- 2021
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47. Calcium carbonate prevents Botryococcus braunii growth inhibition caused by medium acidification
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Fumio Hasegawa, Kenji Imou, Yutaka Kaizu, Kenichi Furuhashi, and Ryoji Miura
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inorganic chemicals ,biology ,food and beverages ,chemistry.chemical_element ,Plant Science ,Aquatic Science ,Calcium ,engineering.material ,biology.organism_classification ,Alkali metal ,chemistry.chemical_compound ,Ammonia ,Calcium carbonate ,chemistry ,Wastewater ,Botryococcus braunii ,engineering ,Fertilizer ,Growth inhibition ,Nuclear chemistry - Abstract
Microalgae, Botryococcus braunii in particular, have received increasing interest owing to their potential as biofuel sources. Although the fertilizer components present in wastewater are useful in reducing the cost of commercial production of microalgae, the ammonium nitrogen (NH4+-N) acidifies the medium and may inhibit the growth of B. braunii. In this study, we aimed to investigate the effectiveness of calcium carbonate in preventing the growth inhibition of B. braunii by suppressing pH decrease caused by NH4+-N. Four types of modified Chu13 media were prepared: a control, one with NH4+-N, one with calcium carbonate, and one with calcium carbonate and NH4+-N. Then, the pH, NH4+-N concentration, B. braunii growth, and hydrocarbon content were measured. We found that in the NH4+-N treatment without calcium carbonate, the pH decreased to approximately 4, and there was almost no algal growth even after 20 days. In contrast, there were no differences in the growth rate and medium pH (7–8) between the treatment with calcium carbonate and the control medium. In addition, calcium ions were leached into the medium with calcium carbonate as the culture progressed, confirming the effectiveness of calcium carbonate in maintaining a constant pH and thus preventing growth inhibition. As such, the addition of calcium carbonate effectively prevents B. braunii growth inhibition by suppressing pH decrease and is more cost-effective than aggressive pH adjustment with alkali or acid or by adding buffer solutions into the medium. This simple and inexpensive method can be used for the removal of ammonia from wastewater.
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- 2021
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48. Lysimeter tests for change in leachate quality from the modified removed soil: interaction between soil and polymer modification agent
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Takuya Miura, Kosuke Nakamura, Jialin Mo, Kazuto Endo, and Hiroyuki Arai
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chemistry.chemical_classification ,chemistry ,media_common.quotation_subject ,Lysimeter ,Environmental engineering ,Environmental science ,Geotechnical engineering ,Quality (business) ,Polymer ,Leachate ,media_common - Published
- 2021
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49. Antitumor activity of solamargine in mouse melanoma model: relevance to clinical safety
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Bárbara Ayumi Miura, Eduardo J. Nassar, Ricardo Andrade Furtado, Denise Crispim Tavares, Saulo Duarte Ozelin, Geórgia Modé Magalhães, Mariza Abreu Miranda, Natália Helen Ferreira, Silvio de Almeida Junior, and Jairo Kenupp Bastos
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Male ,DNA damage ,Health, Toxicology and Mutagenesis ,Melanoma, Experimental ,Mitosis ,Antineoplastic Agents ,Spleen ,Pharmacology ,Toxicology ,medicine.disease_cause ,Solanaceous Alkaloids ,Nephrotoxicity ,Mice ,chemistry.chemical_compound ,Cell Line, Tumor ,medicine ,Animals ,Yttrium ,Solamargine ,Alkaloid ,Melanoma ,Silanes ,medicine.disease ,Mice, Inbred C57BL ,medicine.anatomical_structure ,Liver ,chemistry ,Nanoparticles ,Skin cancer ,Genotoxicity ,DNA Damage - Abstract
Melanoma is the most aggressive type of skin cancer, and thus it is important to develop new drugs for its treatment. The present study aimed to examine the antitumor effects of solamargine a major alkaloid heteroside present in Solanum lycocarpum fruit. In addition solamargine was incorporated into nanoparticles (NP) of yttrium vanadate functionalized with 3-chloropropyltrimethoxysilane (YVO4:Eu3+:CPTES:SM) to determine antitumor activity. The anti-melanoma assessment was performed using a syngeneic mouse melanoma model B16F10 cell line. In addition, systemic toxicity, nephrotoxic, and genotoxic parameters were assessed. Solamargine, at doses of 5 or 10 mg/kg/day administered subcutaneously to male C57BL/6 mice for 5 days, decreased tumor size and frequency of mitoses in tumor tissue, indicative of a decrease in cell proliferation. Treatments with YVO4:Eu3+:CPTES:SM significantly reduced the number of mitoses in tumor tissue, associated with no change in tumor size. There were no apparent signs of systemic toxicity, nephrotoxicity, and genotoxicity initiated by treatments either with solamargine alone or plant alkaloid incorporated into NP. The animals treated with YVO4:Eu3+:CPTES:SM exhibited significant increase in spleen weight accompanied by no apparent histological changes in all tissues examined. In addition, animals treated with solamargine (10 mg/kg/day) and YVO4:Eu3+:CPTES:SM demonstrated significant reduction in hepatic DNA damage which was induced by tumor growth. Therefore, data suggest that solamargine may be considered a promising candidate in cancer therapy with no apparent toxic effects.
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- 2021
- Full Text
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50. Apoptotic Effects of a Thioether Analog of Vitamin K3 in a Human Leukemia Cell Line
- Author
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Eiichi Tokuda, Kenji Nishizawa, Kenzo Yamanaka, Yasuyo Shimoda, Motofumi Miura, Takashi Suzuki, Toshimitsu Nakayama, Koichi Kato, Mikana Suzuki, Satoru Asami, Takashi Kawakubo, and Shin-ichi Ono
- Subjects
chemistry.chemical_classification ,Programmed cell death ,chemistry.chemical_compound ,Enzyme ,Thioether ,Epidermal growth factor ,Chemistry ,Cell culture ,Apoptosis ,Phosphorylation ,Toxicology ,Receptor ,Cell biology - Abstract
Research suggests that thioether analogs of vitamin K3 (VK3) can act to preserve the phosphorylation of epidermal growth factor receptors by blocking enzymes (phosphatases) responsible for their dephosphorylation. Additionally, these derivatives can induce apoptosis via mitogen-activated protein kinase and caspase-3 activation, inducing reactive oxygen species (ROS) production, and apoptosis. However, vitamin K1 exhibits only weak inhibition of phosphatase activity, while the ability of VK3 to cause oxidative DNA damage has raised concerns about carcinogenicity. Hence, in the current study, we designed, synthesized, and screened a number of VK3 analogs for their ability to enhance phosphorylation activity, without inducing off-target effects, such as DNA damage. 3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide (MTT) assay revealed that each analog produced a different level of cytotoxicity in the Jurkat human leukemia cell line; however, none elicited a cytotoxic effect that differed significantly from that of the control. Of the VK3 analogs, CPD5 exhibited the lowest EC50, and flow cytometry results showed that apoptosis was induced at final concentrations of ≥10 μM; hence, only 0.1, 1, and 10 μM were evaluated in subsequent assays. Furthermore, CPD5 did not cause vitamin K-attributed ROS generation and was found to be associated with a significant increase in caspase 3 expression, indicating that, of the synthesized thioether VK3 analogs, CPD5 was a more potent inducer of apoptosis than VK3. Hence, further elucidation of the apoptosis-inducing effect of CPD5 may reveal its efficacy in other neoplastic cells and its potential as a medication.
- Published
- 2021
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