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Search Results: 1 - 10 of 1071 matches for " Tsuyoshi Ochiai "
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The Synergistic Antibacterial Performance of a Cu/WO3-Added PTFE Particulate Superhydrophobic Composite Material  [PDF]
Kentaro Yamauchi, Tsuyoshi Ochiai, Goro Yamauchi
Journal of Biomaterials and Nanobiotechnology (JBNB) , 2015, DOI: 10.4236/jbnb.2015.61001
Abstract: The synergistic antibacterial performance against Escherichia coli (E. coli), Staphylococcus aureus and methicillin-resistant Staphylococcus aureus (MRSA) of a Cu/WO3-added PTFE (polytetrafluoroethylene) particulate composite was reported in the previous paper. The origin of the synergistic antibacterial performance investigated by evaluating the photocatalytic decomposition of the Cu/WO3-added PTFE particulate composite material is reported in the present paper. Addition of Cu/WO3, visible-light-sensitive photocatalyst, to the PTFE particle dispersed superhydrophobic composite does not deteriorate the superhydrophobic property of the composite. Furthermore the existence of the polytetrafluoroethylene (PTFE) particles dispersed in the composite enhances the antibacterial property caused by the Cu/WO3. The authors call this “The synergistic effect”. In this study, a novel synergistic property of the Cu/WO3-added PTFE particulate composite was investigated by evaluating the degradation of gaseous acetaldehyde on the composite surface using visible light (10,000 lx) and UV-A (1 mW·cm-1) illumination. The 12 wt% Cu/WO3-8 wt% binder-80 wt% PTFE composite shows the synergistic visible-light-sensitive photocatalytic property. But 12 wt% Cu/WO3-44 wt% PTFE-44 wt% binder composite no longer shows the synergistic property of visible-light-sensitive photocatalytic property. The synergetic performance of visible-light-sensitive photocatalytic property appears only when PTFE concentration is larger than the critical point over which superhydrophobic property appears in accordance with the particulate composite model derived by the one of the authors. The hydrophobic surface leads to the low surface free energy derived by the revised Fowkes’s theory, which makes it difficult for bacteria to stick to the hydrophobic surface of the composite. Even if bacteria stick to the surface, they are decomposed by the visible-light-sensitive photocatalyst. This is the reason why the synergistic antibacterial performance against bacteria appears.
Synergistic Antibacterial Performance of a Cu/WO3-Added PTFE Particulate Superhydrophobic Composite under Visible-Light Exposure  [PDF]
Yanyan Yao, Kentaro Yamauchi, Goro Yamauchi, Tsuyoshi Ochiai, Taketoshi Murakami, Yoshinobu Kubota
Journal of Biomaterials and Nanobiotechnology (JBNB) , 2012, DOI: 10.4236/jbnb.2012.34042
Abstract: Addition of TiO2 to a polytetrafluoroethylene (PTFE) particle-dispersed composite contributes to the self-cleaning properties of the water-repellent composite. However, its application is limited to outdoor usage or under ultraviolet (UV) irradiation. In this study, a novel visible-light-sensitive photocatalytic and superhydrophobic material was developed by adding Cu/WO3 to a PTFE particulate composite material to overcome this deficit. A remarkable property of this novel composite material is the synergistic antibacterial performance against Escherichia coli (E. coli), Staphylo-coccus aureus, and methicillin-resistant Staphylococcus aureus compared with the addition of Cu/WO3 without PTFE particles material. During 24-h exposure in visible light at 2000 lx, the number of viable cells of the three strains on the surface of the 8wt% Cu/WO3-added PTFE particulate composite decreased from 2 – 4 × 105 colony-formation units (CFUs) to less than 10, the limit of detection. This bactericidal rate is four times higher than that of 8wt% Cu/WO3 without PTFE particles material, which is attributed to the air trapped in the rough surface of the novel material providing additional oxygen to the photocatalytic reaction. Even for exposure to visible light at 100 lx, the decrease in CFUs of E. coli on the 12wt% Cu/WO3-added PTFE particulate composite reached nearly 2.0 logs. The characterization of the Cu/WO3-added PTFE particulate composite indicated that the composite material containing 80wt% PTFE maintained a superhydrophobic or water-repellent property with a water contact angle >150, although the Cu/WO3 in the composite material remained hydrophilic under visible light. The Cu/WO3-added PTFE particulate composite displayed photo-catalytic reactions to decompose oleic acid adsorbed on its surface and gaseous acetaldehyde under UV-A and visible-light illumination. All results demonstrate that the Cu/WO3-added PTFE particulate composite material may be used in sterilization, as a water repellent, for self-cleaning, and in the oxidative decomposition of volatile organic compounds (VOC) both indoors and outdoors.
Development of a Coil-Shape Photocatalysis-Plasma Synergistic Reactor for a Practical and Long-Term Usable Air-Cleaner  [PDF]
Tsuyoshi Ochiai, Yuji Hayashi, Erina Ichihashi, Tadashi Machida, Yoshitsugu Uchida, Shoko Tago, Yuko Morito, Akira Fujishima
American Journal of Analytical Chemistry (AJAC) , 2014, DOI: 10.4236/ajac.2014.58055
Abstract: A novel air-cleaner with a coil-shape photocatalysis-plasma synergistic reactor was developed. The air-cleaner showed 95% ± 1% reduction of a TVOCs concentration in tobacco smoke at “single-pass” condition. Air-purification activity of the air-cleaner was stably-maintained after the treatment of 12,000 cigarettes of tobacco smoke.
Quantitative Microbiological Evaluation of Salmonella Typhimurium Shed in Diarrhea, Loose, and Normal Stools of Infected Pigs  [PDF]
Tsuyoshi Tanaka, Yasuo Imai, Naosuke Kumagae, Takashi Sasaki, Narutoshi Ochiai, Katsuyoshi Uruno, Haruki Kitazawa, Tadao Saito, Shizuo Sato
Open Journal of Veterinary Medicine (OJVM) , 2014, DOI: 10.4236/ojvm.2014.44007
Abstract:

Control of within-herd transmission of Salmonella is important for reducing the prevalence of this organism on pig farms and for preventing Salmonella-contamination of pork. At the farm level, understanding the within-herd transmission of Salmonella can lead to more effective control. Salmonella infection is dependent on the inoculation dose; hence, quantitative evaluation of Salmonella shed in feces would provide useful information for developing effective measures. In this study, to reproduce and evaluate the number of Salmonella shed in diarrhea, loose stools, and normal feces, weaned pigs were inoculated with 3.2 × 109, 3.2 × 107, and 3.2 × 105 cfu of Salmonella Typhimurium, respectively. The number of S. Typhimurium shed in the feces peaked within 1 week post-inoculation in every group and the most amount of diarrhea and loose stools were observed within 2 weeks post-inoculation. Diarrhea occurred 10 times (six pigs), and loose stools were observed 25 times (11 pigs). The average concentration of S. Typhimurium shed in diarrhea, loose stools, and normal feces was 1.0 × 108, 1.6 × 104, and 7.1 × 10

Electrospinning Preparation and Photocatalytic Activity of Porous TiO2 Nanofibers
Shanhu Liu,Baoshun Liu,Kazuya Nakata,Tsuyoshi Ochiai,Taketoshi Murakami,Akira Fujishima
Journal of Nanomaterials , 2012, DOI: 10.1155/2012/491927
Abstract: Porous TiO2 nanofibers were prepared via a facile electrospinning method. The carbon nanospheres were mixed with the ethanol solution containing both poly(vinylpyrrolidone) and titanium tetraisopropoxide for electrospinning; and subsequent calcination of as-spun nanofibers led to thermal decomposition of carbon nanospheres, leaving behind pores in the TiO2 nanofibers. The morphology and phase structure of the products were investigated with scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray diffraction (XRD). Furthermore, the photocatalytic activity of porous TiO2 nanofibers was evaluated by photodecomposition of methylene blue under UV light. Results showed that the porous TiO2 nanofibers have higher surface area and enhanced photocatalysis activity, compared to nonporous TiO2 nanofibers.
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 Novel Strategy for Enrichment and Isolation of Osteoprogenitor Cells from Induced Pluripotent Stem Cells Based on Surface Marker Combination
Hiromi Ochiai-Shino, Hiroshi Kato, Takashi Sawada, Shoko Onodera, Akiko Saito, Tsuyoshi Takato, Takahiko Shibahara, Takashi Muramatsu, Toshifumi Azuma
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0099534
Abstract: In this study, we developed a new method to stimulate osteogenic differentiation in tissue-nonspecific alkaline phosphatase (TNAP)-positive cells liberated from human induced pluripotent stem cells (hiPSCs)-derived embryoid bodies (EBs) with 14 days long TGF-β/IGF-1/FGF-2 treatment. TNAP is a marker protein of osteolineage cells. We analyzed and isolated TNAP-positive and E-cadherin-negative nonepithelial cells by fluorescence-activated cell sorting. Treating the cells with a combination of transforming growth factor (TGF)-β, insulin-like growth factor (IGF)-1, and fibroblast growth factor (FGF)-2 for 14 days greatly enhanced TNAP expression and maximized expression frequency up to 77.3%. The isolated cells expressed high levels of osterix, which is an exclusive osteogenic marker. Culturing these TNAP-positive cells in osteoblast differentiation medium (OBM) led to the expression of runt-related transcription factor 2, type I collagen, bone sialoprotein, and osteocalcin (OCN). These cells responded to treatment with activated vitamin D3 by upregulating OCN. Furthermore, in OBM they were capable of generating many mineralized nodules with strong expression of receptor activator of NF-kappaB ligand and sclerostin (SOST). Real-time RT-PCR showed a significant increase in the expression of osteocyte marker genes, including SOST, neuropeptide Y, and reelin. Scanning electron microscopy showed dendritic morphology. Examination of semi-thin toluidine blue-stained sections showed many interconnected dendrites. Thus, TNAP-positive cells cultured in OBM may eventually become terminally differentiated osteocyte-like cells. In conclusion, treating hiPSCs-derived cells with a combination of TGF-β, IGF-1, and FGF-2 generated TNAP-positive cells at high frequency. These TNAP-positive cells had a high osteogenic potential and could terminally differentiate into osteocyte-like cells. The method described here may reveal new pathways of osteogenesis and provide a novel tool for regenerative medicine and drug development.
Evaluation of the Efficacy and Safety for Atopic Dry Skin of a Medicinal Moisturizing Lotion (Mentholatum AP Soft Medicinal Moisture Lotion) Prepared by a High-Pressure Emulsification Method  [PDF]
Tokuya Omi,Yuriko Ochiai
Journal of Cosmetics, Dermatological Sciences and Applications (JCDSA) , 2013, DOI: 10.4236/jcdsa.2013.32023
Abstract: In order to evaluate the efficacy and safety of Mentholatumò AP Soft Lotion (APA), which is a Vaseline-based preparation that has been converted to nanoparticles by high-pressure emulsification technology, we conducted a study of 4-week continuous use on the atopic dry skin of patients with minor to moderate atopic dermatitis (AD). The results showed that improvements in the skin findings (dryness and scaling) and itching were observed beginning one week after starting to apply APA and that the symptoms had almost completely resolved at 3 to 4 weeks after the start of application. In addition, a significant increase in the degree of high-frequency conductivity, which is an indicator of the amount of moisture in the stratum corneum, and significant decrease in transepidermal water loss (TEWL) were observed, and improvements in skin functions were observed. The results for overall degree of improvement showed “improvement” or better in 100% of the subjects, and no side effects were observed in any of the cases. Based on the above results, it was concluded that APA is a preparation that has excellent efficacy and safety as skin care for atopic dry skin, in which reduced stratum corneum function is observed in the skin, and as a supplemental method of treatment of AD or treatment method to maintain remissions.
Evaluation of the Efficacy and Safety for Atopic Dry Skin of a Medicinal Moisturizing Lotion (Mentholatum AP Soft Medicinal Moisture Lotion) Prepared by a High-Pressure Emulsification Method  [PDF]
Tokuya Omi, Yuriko Ochiai
Journal of Cosmetics, Dermatological Sciences and Applications (JCDSA) , 2013, DOI: 10.4236/jcdsa.2013.32023
Abstract:

In order to evaluate the efficacy and safety of Mentholatumò AP Soft Lotion (APA), which is a Vaseline-based preparation that has been converted to nanoparticles by high-pressure emulsification technology, we conducted a study of 4-week continuous use on the atopic dry skin of patients with minor to moderate atopic dermatitis (AD). The results showed that improvements in the skin findings (dryness and scaling) and itching were observed beginning one week after starting to apply APA and that the symptoms had almost completely resolved at 3 to 4 weeks after the start of application. In addition, a significant increase in the degree of high-frequency conductivity, which is an indicator of the amount of moisture in the stratum corneum, and significant decrease in transepidermal water loss (TEWL) were observed, and improvements in skin functions were observed. The results for overall degree of improvement showed “improvement” or better in 100% of the subjects, and no side effects were observed in any of the cases. Based on the above results, it was concluded that APA is a preparation that has excellent efficacy and safety as skin care for atopic dry skin, in which reduced stratum corneum function is observed in the skin, and as a supplemental method of treatment of AD or treatment method to maintain remissions.

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