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Search Results: 1 - 10 of 1273 matches for " Munetoshi Sakai "
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Antibacterial Activity of Hydrophobic Composite Materials Containing a Visible-Light-Sensitive Photocatalyst
Kentaro Yamauchi,Yanyan Yao,Tsuyoshi Ochiai,Munetoshi Sakai,Yoshinobu Kubota,Goro Yamauchi
Journal of Nanotechnology , 2011, DOI: 10.1155/2011/380979
Abstract: The conventional superhydrophobic surface offered by PTFE provides no sterilization performance and is not sufficiently repellent against organic liquids. These limit PTFE's application in the field of disinfection and result a lack of durability. N-doped TiO2 photocatalyst added PTFE composite material was developed to remedy these shortcomings. This paper reports the surface characteristics, and the bactericidal and self-cleaning performance of the newly-developed composite material. The material exhibited a contact angle exceeding 150 degrees consistent with its hydrophobicity despite the inclusion of the hydrophilic N-doped TiO2. The surface free energy obtained for this composite was 5.8?mN/m. Even when exposed to a weak fluorescent light intensity (100 lx) for 24 hours, the viable cells of gram-negative E. coli on the 12% N-doped TiO2-PTFE film were reduced 5 logs. The higher bactericidal activity was also confirmed on the gram-positive MRSA. Compared with the N-doped TiO2 coating only, the inactivation rate of the composite material was significantly enhanced. Utilizing the N-doped TiO2 with the PTFE composite coating could successfully remove, by UV illumination, oleic acid adsorbed on its surface. These results demonstrate the potential applicability of the novel N-doped TiO2 photocatalyst hydrophobic composite material for both indoor antibacterial action and outdoor contamination prevention. 1. Introduction It is well known that the conventional superhydrophobic surface offered by polytetrafluoroethylene (PTFE) provides no sterilization performance and is not sufficiently repellent against organic matters. Thus, there is potential risk for bacteria to adhere to its surface more readily in ambient air, as well as organic matters is considered to reduce the durability of the superhydrophobic performance. To remedy this shortcoming, anatase titanium dioxide (TiO2), a UV light-sensitive photocatalyst added water repellent composite material has been developed in our previous study [1–5]. TiO2 was used to demonstrate the inactivation of various bacteria, such as Escherichia coli (E. coli), methicillin-resistant Staphylococcus aureus (MRSA), Pseudomonas aeruginosa (P. aeruginosa), Legionella pneumophila (L. pneumophila) [6–8], and Clostridium difficile spores [8]. The inclusion of TiO2 to the PTFE coating is expected to generate antimicrobial and self-cleaning properties, which would expand its scope of application. Anatase TiO2-added PTFE composite material is not only water-repellent but also exhibits self-cleaning properties. However, because
Photomechanical Energy Conversion of Photoresponsive Fibers Exhibiting Bending Behavior
Kazuya Nakata,Yosuke Ishikawa,Munetoshi Sakai,Baoshun Liu,Tsuyoshi Ochiai,Hideki Sakai,Taketoshi Murakami,Masahiko Abe,Akira Fujishima
International Journal of Photoenergy , 2012, DOI: 10.1155/2012/574124
Abstract: Photoresponsive fibers based on poly(acrylamide) (PAA) with methylene blue (MB) dye were prepared. All semicircular fibers show bending towards the direction of the flat surface of the fiber when illuminated. The fibers recover their initial shape when the illumination stops. The fiber is heated upon illumination and cooled to room temperature once the illumination is stopped. The fiber also is sensitive to humidity, showing bending behavior towards the direction of the flat surface of the fiber upon changing the humidity. The mechanical energy of the PAA/MB fiber is approximately 0.6?mN for the bending direction when it is illuminated. A possible mechanism for the bending behavior is as follow: (1) the fiber is heated upon illumination because of the photothermal effect, (2) the fiber loses water molecules, (3) the fiber shrinks; bending towards the direction of the flat surface of the fiber occurs because of a difference in the shrinkage for the flat surface and the other side of the fiber. Finally, we demonstrated that a PP ball (1.5?mg) can be moved by the mechanical energy produced by the changing shape of the fiber upon illumination. 1. Introduction Utilization of solar energy is a key factor for development of a sustainable society. Among a number of approaches for solar energy conversion, photomechanical energy conversion has significant advantages such as direct energy conversion from photo to mechanical, which may potentially lead to high energy conversion efficiency, no cable for working, and space-saving. Typical photomechanical materials that change shape in response to light are liquid crystalline elastomer films based on azobenzene derivatives [1–14]. These materials show bending behavior upon illumination because the structure of azobenzene derivative molecules in the film changes from trans to cis form, which generates mechanical energy. Although these materials have attracted much attention because they can be applied as photodriven motors [9], actuators [1, 3, 4, 6, 8, 10, 11, 15–17], and new types of solar energy conversion systems [2, 5, 7, 11–14, 16, 18, 19], they need multiple synthetic procedures followed by rubbing to align the azobenzene molecules, which makes them impractical for many applications. Materials exhibiting a volume change in response to light are of interest [20–22]. For example, hydrogels that show a volume change upon the application of light have been reported previously [21–23]. The basic mechanism for the volume change is a solvent absorption/desorption process. Suzuki and Tanaka reported that a polymer gel
A new genus and species of myrmecophilous aphodiine beetle (Coleoptera, Scarabaeidae) inhabiting the myrmecophytic epiphyte Platycerium sp. (Polypodiaceae) in the Bornean rainforest canopy
Munetoshi Maruyama
ZooKeys , 2010, DOI: 10.3897/zookeys.34.281
Abstract: Pterobius itiokai Maruyama, gen. n. and sp. n., (Coleoptera: Scarabaeidae: Aphodiinae) is described from Lambir Hills National Park, Borneo based on specimens collected from a Crematogaster difformis ant nest in the myrmecophytic epiphytic fern genus Platycerium. Pterobius belongs to the tribe Eupariini and is closely related to the Indo-Australian genus Cnematoplatys.
Termitotrox cupido sp. n. (Coleoptera, Scarabaeidae), a new termitophilous scarab species from the Indo-Chinese subregion, associated with Hypotermes termites
Munetoshi Maruyama
ZooKeys , 2012, DOI: 10.3897/zookeys.254.4285
Abstract: Termitotrox cupido sp. n. is described from Cambodia and represents the first discovery of Termitotrox Reichensperger, 1915 from the Indo-Chinese subregion of the Oriental region. The type series was collected from fungus garden cells of Hypotermes makhamensis Ahmad, 1965 (Isoptera, Termitidae, Macrotermitinae). Hypotermes Holmgren, 1917 was previously an unknown host of Termitotrox species. The new species is readily distinguished from all known congeners bywing-shaped trichomes on the elytra and is most probably the world’s smallest scarab, at 1.2 mm in length.
Growth of Gallium Oxide Nanowires by Pulsed Laser Deposition  [PDF]
Hiroyasu Yamahara, Munetoshi Seki, Hitoshi Tabata
Journal of Crystallization Process and Technology (JCPT) , 2012, DOI: 10.4236/jcpt.2012.24017
Abstract: We report on the synthesis of gallium oxide nanowires by pulsed laser deposition using a gold catalyst. In the vapor-liquid-solid process, gold thickness was the crucial parameter for deciding the morphology of nanowires. In the case of 1 nm thick gold, homogeneous nanowire growth was confirmed at temperatures of 700°C to 850°C. Transmission electron microscopy and selected area electron diffraction measurements showed that the nanowires were polycrystalline. In the cathode luminescence spectra, UV, blue, green and red emission peaks were observed, as reported in previous studies. As growth temperature was increased, the relative intensities of blue, green, and red emissions decreased. Thermal annealing treatments were effective in decreasing the blue, green and red emission peaks, suggesting that these emission peaks were associated with oxygen vacancies.
Onset Time Profiles for Syncope Associated with α1-Adrenoceptor Blockers in Males: Analysis of a Spontaneous Adverse Drug Event Database  [PDF]
Katsuhiro Ohyama, Masaya Furumoto, Munetoshi Sugiura
Pharmacology & Pharmacy (PP) , 2018, DOI: 10.4236/pp.2018.912040
Abstract:
Background: α1-Adrenoceptor blockers (α1Bs) are used for the treatment of benign prostatic hyperplasia and hypertension, but they are known to cause hypotension-related adverse events. The objective of the present study was to evaluate the onset time profiles for syncope associated with the use of α1Bs. Methods: We analyzed the data obtained from?the Japanese Adverse Drug Event Report (JADER) database for a period from April 2004 until November 2016 and calculated reporting odds ratios (RORs) for eight α1Bs available on the Japanese market, using disproportionality analysis. Moreover, time information recorded in the JADER database was analyzed to evaluate the onset times of adverse events. Results: In total, 186,724 reports for males older than 20 years were analyzed. Significant RORs for syncope, with 95% confidence intervals, were obtained for naftopidil (2.53, 1.81 - 3.53), silodosin (4.24, 2.37 - 5.20), and tamsulosin (2.22, 1.75 - 2.81). The median onset times of syncope for naftopidil, silodosin, and tamsulosin were 37, 26, and 108 days, respectively. The shape parameters obtained by fitting the data for the three α1Bs to the Weibull distribution were all less than 1.0, indicating that all these drugs could be classified as the early failure type. The cumulative incidence rates showed that the onset times of syncope tended to be similar among the three α1Bs.
The Ceratocanthinae of Ulu Gombak: high species richness at a single site, with descriptions of three new species and an annotated checklist of the Ceratocanthinae of Western Malaysia and Singapore (Coleoptera, Scarabaeoidea, Hybosoridae)
Alberto Ballerio,Munetoshi Maruyama
ZooKeys , 2010, DOI: 10.3897/zookeys.34.268
Abstract: The remarkable species richness of Ceratocanthinae (Coleoptera: Scarabaeoidea: Hybosoridae) found at Ulu Gombak (Selangor, West Malaysia), a secondary rainforest research station, is discussed. Eighteen species have been collected, mainly in nests of termites (Isoptera) and bess beetles (Coleoptera: Passalidae). Among them at least seven are new species, three of them here described: Madrasostes hashimi sp. n., Madrasostes mirificum sp. n., and Pterorthochaetes tsurui sp. n. Four other species (Madrasostes agostii Paulian, Madrasostes clypeale Paulian, Madrasostes depressum Paulian, and Madrasostes simplex Paulian) are recorded for the first time for West Malaysia and three for new states within West Malaysia (Pterorthochaetes insularis Gestro, Madrasostes malayanum Paulian and Madrasostes sculpturatum Paulian). A checklist of the 34 Ceratocanthinae recorded so far from West Malaysia and Singapore is provided with taxonomic, distributional and morphological remarks on some species.
Asymmetric Electrostatic Force  [PDF]
Katsuo Sakai
Journal of Electromagnetic Analysis and Applications (JEMAA) , 2014, DOI: 10.4236/jemaa.2014.610026
Abstract: Asymmetric electrostatic forces are a very interesting and new phenomenon. The magnitude of an electrostatic force that acts on a point charge does not change when the direction of the electric field is reversed. On the contrary, the magnitude of the electrostatic force that acts on a charged asymmetric shaped conductor does change when the direction of the electric field is reversed. 5 years ago, this phenomenon was reported by a simple experiment and a simulation and named as an Asymmetric electrostatic force unofficially by the author. After that, several simulations confirmed this phenomenon. However, several experiments did not yet confirm it clearly. The difference between the simulations and the experiments depends upon differences of their conditions. The simulations had been done under ideal (perfect) conditions; the experiments, on the contrary, had been done under actual (not perfect) conditions. In the new experiment, its conditions were improved to near ideal (perfect) conditions. As a result the existence of the Asymmetric electrostatic force was more clearly confirmed.
Surface Properties of Cement Paste Evaluated by Scanning Probe Microscopy  [PDF]
Yuya Sakai
Open Journal of Civil Engineering (OJCE) , 2016, DOI: 10.4236/ojce.2016.64052
Abstract: The microscopic physical properties of Hardened Cement Paste (HCP) surfaces were evaluated by using Scanning Probe Microscopy (SPM). The cement pastes were cured under a hydrostatic pressure of 400 MPa and the contacting surfaces with a slide glass during the curing were studied. Scanning Electron Microscope (SEM) observation at a magnification of 7000 revealed smooth surfaces with no holes. The surface roughness calculated from the SPM measurement was 4 nm. The surface potential and the frictional force measured by SPM were uniform throughout the measured area 24 h after the curing. However, spots of low surface potential and stains of low frictional force and low viscoelasticity were observed one month after curing. This change was attributed to the carbonation of hydrates.
A Study of Weighted Polynomial Approximations with Several Variables (II)  [PDF]
Ryozi Sakai
Applied Mathematics (AM) , 2017, DOI: 10.4236/am.2017.89093
Abstract: In this paper we investigate weighted polynomial approximations with several variables. Our study relates to the approximation for \"\" by weighted polynomial. Then we will give some results relating to the Lagrange interpolation, the best approximation, the Markov-Bernstein inequality and the Nikolskii- type inequality.
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