12 results on '"T. Kougo"'
Search Results
2. Fabrication and characterization of polycrystalline bulk ZnO with large grain size of ∼100 µm by the spark plasma sintering
- Author
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T. Kougo and Akihiko Yoshikawa
- Subjects
Fabrication ,Materials science ,Atmospheric pressure ,Electrical resistivity and conductivity ,Metallurgy ,Spark plasma sintering ,Sintering ,Crystallite ,Composite material ,Condensed Matter Physics ,Grain size ,Characterization (materials science) - Abstract
We investigated to fabricate polycrystalline ZnO bulk crystal with large grain size up to 100 µm by the spark plasma sintering (SPS) in the atmosphere of low-vacuum of ∼1 Pa air or in atmospheric pressure air. 1 µm average-size ZnO powder of 99.999% purity was used as the raw material for sintering. The shape of samples was disk-like of which diameter and thickness were 20 mm and 0.5–1.0 mm, respectively. We studied how the sintering conditions, in particular the sintering temperature and the applied pressure, affect the properties of sintered ZnO crystals. No additive to enhance the sintering process was used in this work. It was found that the SPS was very effective to enhance the sintering itself resulting in the grain size ranging from a few µm to ∼100 µm. Further the electrical properties of the sintered ZnO crystals were found to be very sensitive to the sintering conditions, i.e., their resistivity varied in the range from 0.02 Ω cm to ∼1000 kΩ cm depending on the grain size. The resistivity saturated in the order of 0.01 Ω cm when the grain size was above about 20 µm. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
- Published
- 2006
3. Metal coated glasses by sputtering and their microfouling properties
- Author
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M. Minekawa, N. Wada, Hideyuki Kanematsu, T. Kougo, Y. Fujita, and Takehiko Hihara
- Subjects
Metal dissolution ,Fogging ,Materials science ,Metallurgy ,Biofilm ,Substrate (electronics) ,biochemical phenomena, metabolism, and nutrition ,Metal ,Chemical engineering ,Sputtering ,visual_art ,visual_art.visual_art_medium ,Degradation (geology) ,Layer (electronics) - Abstract
Some elements as contaminant tend to be concentrated in biofilm. In order to prevent the fogging of glass, it is very important to control biofilm formation by metal dissolution. In this study, Metals were deposited on glass substrate by Helicon-wave-excited-plasma sputtering process. Sample was very thin metals layer like as half mirror, it could transmit light. The results of biofilm formation test, biofilm formation were inhibited on Cu, Sn and Cr, and light transmission of these samples was not degradation. It could be said that inhibition of biofilm formation was effective to suppressing cloudiness.
- Published
- 2014
4. Prevention of Oral Radiation Mucositis Using a Specialized Amino Acid Mixture
- Author
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Natsuo Tomita, Toshio Shigetomi, K. Kimura, D. Miyamoto, Motoki Yoshida, K. Takehana, Chiyoko Makita, Hiroyuki Tachibana, T. Kodaira, A. Shimizu, T. Kougo, and Yutaro Koide
- Subjects
chemistry.chemical_classification ,Cancer Research ,Radiation ,business.industry ,Pharmacology ,medicine.disease ,Amino acid ,Oral radiation ,Oncology ,chemistry ,Mucositis ,medicine ,Radiology, Nuclear Medicine and imaging ,business - Published
- 2015
5. Assessment of Peak Flow Meters in Children
- Author
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Y. Yoshida, C. Hosobe, K. Shirota, T. Kougo, M. Takase, M. Hida, and Y. Inaba
- Subjects
Hydrology ,Environmental science ,Flow measurement - Published
- 1995
6. Erbium-doped fiber amplifier pumped at 1.48 mu m with extremely high efficiency
- Author
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T. Kougo, H. Kanamori, Masayuki Nishimura, M. Shigematsu, and T. Kashiwada
- Subjects
Optical fiber ,Materials science ,business.industry ,Plastic-clad silica fiber ,Polarization-maintaining optical fiber ,Graded-index fiber ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,law.invention ,Optics ,Double-clad fiber ,law ,Dispersion-shifted fiber ,Optoelectronics ,Electrical and Electronic Engineering ,business ,Plastic optical fiber ,Photonic-crystal fiber - Abstract
An erbium-doped fiber amplifier pumped at 1.48 mu m with extremely high efficiency has been developed. The fiber has a relative refractive index difference of 2.0% and Er/sup 3+/ ions and alumina are doped only in a limited area of the core. A slope efficiency of 86% and a gain coefficient of 6.3 dB/mW have been achieved by 1.48 mu m pumping along with excellent spectral signal output performance. In spite of its small mode-field diameter, it is possible to fusion-splice the fiber to standard dispersion-shifted fibers with low loss due to diffusion of fluorine dopant in the classing. >
- Published
- 1991
7. Metal Coated Glasses by Sputtering and their Microfouling Properties.
- Author
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T. Kougo, H. Kanematsu, N. Wada, T. Hihara, M. Minekawa, and Y. Fujita
- Subjects
- *
BIOFILMS , *HELICONS (Electromagnetism) , *SPUTTERING (Physics) , *COPPER , *TIN , *CHROMIUM - Abstract
Some elements as contaminant tend to be concentrated in biofilm. In order to prevent the fogging of glass, it is very important to control biofilm formation by metal dissolution. In this study, Metals were deposited on glass substrate by Helicon-wave-excited-plasma sputtering process. Sample was very thin metals layer like as half mirror, it could transmit light. The results of biofilm formation test, biofilm formation were inhibited on Cu, Sn and Cr, and light transmission of these samples was not degradation. It could be said that inhibition of biofilm formation was effective to suppressing cloudiness. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
8. Biofilm Formation Plays a Crucial Rule in the Initial Step of Carbon Steel Corrosion in Air and Water Environments.
- Author
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Ogawa A, Takakura K, Hirai N, Kanematsu H, Kuroda D, Kougo T, Sano K, and Terada S
- Abstract
In this study, we examined the relationship between the effect of a zinc coating on protecting carbon steel against biofilm formation in both air and water environments. SS400 carbon steel coupons were covered with a zinc thermal spray coating or copper thermal spray coating. Coated coupons were exposed to either air or water conditions. Following exposure, the surface conditions of each coupon were observed using optical microscopy, and quantitatively analyzed using an x-ray fluorescence analyzer. Debris on the surface of the coupons was used for biofilm analysis including crystal violet staining for quantification, Raman spectroscopic analysis for qualification, and microbiome analysis. The results showed that the zinc thermal spray coating significantly inhibited iron corrosion as well as biofilm formation in both air and water environments. The copper thermal spray coating, however, accelerated iron corrosion in both air and water environments, but accelerated biofilm formation only in a water environment. microbially-influenced-corrosion-related bacteria were barely detected on any coupons, whereas biofilms were detected on all coupons. To summarize these results, electrochemical corrosion is dominant in an air environment and microbially influenced corrosion is strongly involved in water corrosion. Additionally, biofilm formation plays a crucial rule in carbon steel corrosion in both air and water, even though microbially-influenced-corrosion-related bacteria are barely involved in this corrosion.
- Published
- 2020
- Full Text
- View/download PDF
9. Effect of drug-coated balloon angioplasty on in-stent restenotic coronary lesions analyzed with optical coherence tomography and serial coronary artery angioscopy.
- Author
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Akutsu N, Ogaku A, Koyama Y, Fujito H, Ebuchi Y, Migita S, Morikawa T, Tamaki T, Mineki T, Kougo T, Kojima K, Iida K, Murata N, Nishida T, Oshima T, Sudo M, Kitano D, Haruta H, Fukamachi D, Takayama T, Hiro T, Hirayama A, and Okumura Y
- Subjects
- Aged, Coated Materials, Biocompatible, Coronary Angiography, Coronary Restenosis surgery, Coronary Vessels surgery, Female, Follow-Up Studies, Graft Occlusion, Vascular surgery, Humans, Male, Neointima pathology, Reoperation, Retrospective Studies, Angioplasty, Balloon, Coronary methods, Angioscopy methods, Coronary Restenosis diagnosis, Coronary Vessels diagnostic imaging, Drug-Eluting Stents adverse effects, Graft Occlusion, Vascular diagnosis, Tomography, Optical Coherence methods
- Abstract
Drug-coated balloon angioplasty (DCBA) has been recognized for its utility in preventing in-stent re-restenosis (ISR); however, imaging of the neointima immediately after treatment and during follow-up has only been described in a few case reports. This study aimed to determine the efficacy and mechanism of the DCBA using imaging studies both immediately after the DCBA and during the follow-up period. We enrolled 15 consecutive patients who underwent DCBA for in-stent restenosis (ISR). The in-stent neointimal volume was evaluated using optical coherence tomography (OCT), and the in-stent yellow grade was assessed using coronary angioscopy (CAS) immediately after DCBA and during the median follow-up period of 9 (8-15) months. The neointimal volume was significantly reduced from 77.1 ± 36.2 mm
3 at baseline to 60.2 ± 23.9 mm3 immediately after DCBA (p = 0.0012 vs. baseline) and to 46.7 ± 21.9 mm3 during the follow-up (p = 0.0002 vs. post DCBA). The yellow grade of the residual plaques at the ISR lesion, which indicated plaque vulnerability, was significantly decreased in the follow-up CAG (from baseline: 1.79 ± 1.03, during the follow-up: 0.76 ± 0.82; p < 0.0001). These data suggest that DCBA may inhibit neointimal formation and provide angioscopic intimal stabilization for ISR lesions.- Published
- 2019
- Full Text
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10. A case of giant saphenous vein graft aneurysm followed serially after coronary artery bypass surgery.
- Author
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Takayama T, Akutsu N, Hiro T, Oya T, Fukamachi D, Haruta H, Iida K, Kougo T, Mineki T, Nishida T, Murata N, Oshima T, Hata H, Shiono M, and Hirayama A
- Abstract
Saphenous vein graft aneurysm (SVGA) is one of the chronic complications after coronary aorta bypass grafting (CABG) and may be caused by atherosclerosis-like phenomena of the vein graft, weakness around the vein valve, rupturing of the suture of the graft anastomosis, or perioperative graft injury. We describe a case of a large, growing saphenous vein graft aneurysm that was followed serially by chest radiography and computed tomography. Eighteen years after CABG, an SVGA (23 × 24 mm) was incidentally detected. The patient was asymptomatic and was followed conservatively. Four years later, coronary computed tomographic angiography showed that the giant aneurysm had grown to 52.1 by 63.8 mm and revealed a second, smaller aneurysm. Finally, the SVG was ultimately resected without bypass via off-pump surgery. Therefore, this case suggested that aggressive treatment that includes surgical intervention should be considered before the aneurysm becomes larger, even if it is asymptomatic.
- Published
- 2016
- Full Text
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11. Serum KL-6 levels in pediatric patients: reference values for children and levels in pneumonia, asthma, and measles patients.
- Author
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Imai T, Takase M, Takeda S, and Kougo T
- Subjects
- Adolescent, Antigens, Neoplasm, Biomarkers blood, C-Reactive Protein analysis, Child, Child, Preschool, Female, Humans, Infant, L-Lactate Dehydrogenase blood, Leukocytes chemistry, Male, Measles complications, Mucin-1, Mucins, Pneumonia classification, Pneumonia diagnosis, Pneumonia etiology, Pulmonary Alveoli metabolism, Reference Values, Sensitivity and Specificity, Antigens blood, Asthma blood, Glycoproteins blood, Measles blood, Pneumonia blood
- Abstract
Serum KL-6 reflects alveolar damage and regeneration of type II pneumocytes, indicating disease activity in various interstitial lung diseases. We conducted a descriptive and observational multiple case-control study to determine the distribution of serum KL-6 levels in pediatric patients with or without respiratory diseases. Subjects were recruited from the patients of a teaching hospital in the suburb of Tokyo. A consecutive series of 401 children (0-16 years old) underwent blood sampling for many clinical reasons. They comprised the following four groups: pneumonia (n = 96), bronchial asthma (n = 101), measles (n = 102), and nonrespiratory diseases (n = 102) as a control group. Standard upper limits of serum KL-6 in a group of children with nonrespiratory disease were 250 U/mL, or half the adult level. No gender or age differences were observed. Elevated serum KL-6 concentrations were observed in severe pneumonia, acute exacerbations of asthma, and measles pneumonia. In the measles group, KL-6 values reflected the presence and severity of complicating pneumonia. We conclude that serum KL-6 levels exceeding 250 U/mL were rarely observed in children without respiratory diseases. In contrast, a substantial proportion of children with common respiratory diseases showed mild to moderate increases in serum KL-6 levels. Elevated serum KL-6 in these children may reflect the presence of alveolar damage, followed by regeneration of type II pneumocytes. However, in order to use serum KL-6 as a marker of interstitial lung diseases in children, a cutoff level should be determined separately., (Copyright 2002 Wiley-Liss, Inc.)
- Published
- 2002
- Full Text
- View/download PDF
12. Release of cytokines from human umbilical vein endothelial cells treated with platinum compounds in vitro.
- Author
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Shi Y, Inoue S, Shinozaki R, Fukue K, and Kougo T
- Subjects
- Endothelium, Vascular metabolism, Endothelium, Vascular pathology, Granulocyte-Macrophage Colony-Stimulating Factor metabolism, Hematopoiesis drug effects, Humans, Hydrogen Peroxide metabolism, Interleukin-1 metabolism, Interleukin-6 metabolism, Interleukin-8 metabolism, Mitochondria drug effects, Umbilical Veins, Antineoplastic Agents toxicity, Carboplatin toxicity, Cisplatin toxicity, Cytokines metabolism, Endothelium, Vascular drug effects, Organoplatinum Compounds toxicity
- Abstract
Endothelial cells (EC) produce cytokines, such as interleukin (IL)-1, IL-6, IL-8 and granulocyte-macrophage colony-stimulating factor (GM-CSF). These cytokines have an important role in the proliferation and differentiation of hematopoietic progenitor cells. On the other hand, anticancer agents generally cause hematopoietic disorders. However, little is known about the effects of chemotherapeutic agents on the secretion of cytokines from EC. Therefore, we investigated if treatment with platinum compounds may stimulate EC to secrete cytokines. EC newly isolated from a human umbilical vein were exposed to cisplatin, carboplatin, or TRK-710 for 80 min, then the cells were washed and placed in fresh medium. The levels of cytokines in the fresh medium were measured by the ELISA method, the levels of intracellular hydrogen peroxide (H2O2) were measured by flow cytometry, and the rhodamine 123-stained live mitochondria of the EC were observed under a confocal laser microscope. Platinum compounds induced cytokine production in human EC: cisplatin most prominently induced the release of IL-1 and IL-6, and TRK-710 had the greatest ability to induce the release of GM-CSF. Intracellular H2O2 production and IL-8 release were transiently induced immediately after treatment with platinum compounds, leading to IL-1 release when H2O2 production was eliminated. These results may provide new insights into the hematological toxicity induced by anticancer agents and the role of IL-1 and IL-6 secreted from EC in this toxicity.
- Published
- 1998
- Full Text
- View/download PDF
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