249 results on '"M. Ohuchi"'
Search Results
2. Numerical simulation of detached plasma in the end-cell of GAMMA 10/PDX for divertor simulation study
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Md. Shahinul Islam, Naomichi Ezumi, G. Lee, Yousuke Nakashima, K. Fukui, Akiyoshi Hatayama, Tsuyoshi Imai, Satoshi Togo, Kazuya Ichimura, Mizuki Sakamoto, M. M. Islam, M. Ohuchi, and Takayuki Yokodo
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Electron density ,Materials science ,Argon ,Plasma parameters ,Mechanical Engineering ,Divertor ,chemistry.chemical_element ,Plasma ,01 natural sciences ,010305 fluids & plasmas ,Ion ,Neon ,Nuclear Energy and Engineering ,chemistry ,Physics::Plasma Physics ,Physics::Space Physics ,0103 physical sciences ,Radiative transfer ,Astrophysics::Solar and Stellar Astrophysics ,General Materials Science ,Atomic physics ,010306 general physics ,Civil and Structural Engineering - Abstract
This research investigates the effect of Argon (Ar) and Neon (Ne) injection on the plasma parameters in the end-cell of GAMMA 10/PDX numerically by using a multi-fluid code. Reduction in the temperature of the electrons and ions is observed according to the increment of impurity injection. The electron density and the particle flux show tendency of roll-over phenomena for Ar injection. Temperature reduction in the electrons and ions during Ar injection is higher than those of the Ne injection. It is also observed that the charge-exchange (CX) loss and radiative power loss for Ar injection is higher than that of the Ne injection. These outcomes indicate that Ar is more effective radiative gas for generating detached plasma.
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- 2017
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3. Numerical Simulation Study of Plasma Flow in the GAMMA10/PDX End-cell Using a Fluid Code
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Mizuki Sakamoto, K. Ichimura, Yousuke Nakashima, H. Takeda, M. M. Islam, Md. Shahinul Islam, M. Ohuchi, Tsuyoshi Imai, K. Shimuzu, K. Fukui, and Akiyoshi Hatayama
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Materials science ,Hydrogen ,Computer simulation ,Plasma parameters ,Divertor ,chemistry.chemical_element ,Plasma ,Electron ,Condensed Matter Physics ,01 natural sciences ,010305 fluids & plasmas ,law.invention ,chemistry ,Impurity ,law ,0103 physical sciences ,Atomic physics ,010306 general physics ,Spark plug - Abstract
In order to understand the effect of impurity injection into divertor plasma, a multi-fluid code was developed and applied to the region from west plug/barrier-cell to end cell in GAMMA 10/PDX. In this research, Ar is applied as impurity neutrals. To investigate the effect of impurity injection on plasma parameters, interactions between Ar impurity and hydrogen bulk plasma were included in this model. Under the condition of injecting neutral hydrogen and impurity Ar, the charge exchange loss between hydrogen ion and neutrals reaches to about 95% and the radiation loss for electron is enhanced to about 45%. Therefore, hydrogen ion and electron temperatures decrease from about 55 eV to 4 eV and 15 eV to 4 eV, respectively. The heat load on the target plate is also reduced by nearly 80% compared with the condition of low injection rate of neutral hydrogen and impurity. It is also observed that the particle flux increases with neutral density and then shows a tendency to saturate in the higher neutral density (> 2.1 × 1018 m–3). (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
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- 2016
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4. Toll-like receptor 2-mediated modulation of growth and functions of regulatory T cells by oral streptococci
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H. Hara, Ayumi Saeki, Akira Hasebe, Taku Segawa, T. Abe, Makoto Ohtani, Naoho Tanizume, Atsuro Yokoyama, Takafumi Arimoto, Masamitsu Kawanami, M. Ohuchi, Masahiro Sugiyama, Hideo Kataoka, and Ken-ichiro Shibata
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CD4-Positive T-Lymphocytes ,Male ,Microbiology (medical) ,Lipoproteins ,Immunology ,Antigen-Presenting Cells ,Mice, Inbred Strains ,Biology ,T-Lymphocytes, Regulatory ,Microbiology ,Streptococcus mutans ,Mice ,Interleukin 21 ,Bacterial Proteins ,Streptococcal Infections ,Nitriles ,Immune Tolerance ,Animals ,Lymphocyte Count ,Sulfones ,IL-2 receptor ,General Dentistry ,Mice, Knockout ,Mouth ,Toll-like receptor ,Interleukin-6 ,Interleukin-2 Receptor alpha Subunit ,Streptococcus gordonii ,NF-kappa B p50 Subunit ,FOXP3 ,Forkhead Transcription Factors ,biology.organism_classification ,Toll-Like Receptor 2 ,In vitro ,Mice, Inbred C57BL ,Disease Models, Animal ,TLR2 ,CD4 Antigens ,Mutation ,Interleukin-2 ,Female ,Spleen - Abstract
This study was designed to determine whether oral streptococci modulate the growth and functions of regulatory T cells. Heat-killed cells of wild-type strains of Streptococcus gordonii and Streptococcus mutans induced the Toll-like receptor 2 (TLR2) -mediated nuclear factor-κB (NF-κB) activation, but their lipoprotein-deficient strains did not. Stimulation with these streptococci resulted in a significant increase in the frequency of CD4(+) CD25(+) Foxp3(+) regulatory T cells in splenocytes derived from both TLR2(+/+) and TLR2(-/-) mice, but the level of increase in TLR2(+/+) splenocytes was stronger than that in TLR2(-/-) splenocytes. Both strains of S. gordonii enhanced the proliferation of CD4(+) CD25(+) Foxp3(+) regulatory T cells isolated from TLR2(+/+) mice at the same level as those from TLR2(-/-) mice in an interleukin-2-independent manner. However, wild-type and lipoprotein-deficient strains of both streptococci did not enhance the suppressive activity of the isolated regulatory T cells in vitro, but rather inhibited it. TLR ligands also inhibited the suppressive activity of the regulatory T cells. Inhibition of the suppressive activity was recovered by the addition of anti-IL-6 antibody. Pretreatment of antigen-presenting cells with the NF-κB inhibitor BAY11-7082 enhanced the suppressive activity of the regulatory T cells. These results suggested that interleukin-6 produced by antigen-presenting cells inhibits the suppressive activity of the regulatory T cells. Wild-type strain, but not lipoprotein-deficient strain, of S. gordonii reduced the frequency of CD4(+) CD25(+) Foxp3(+) regulatory T cells in the acute infection model, whereas both strains of S. gordonii increased it in the chronic infection model mice. Hence, this study suggests that oral streptococci are capable of modulating the growth and functions of regulatory T cells in vitro and in vivo.
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- 2013
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5. 584P Controlled release of anti-cancer flutamide-related escape products under exposure to magnetic fields
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K. Nakamura, Hidenori Nakagawa, H. Kawase, H. Kamei, and M. Ohuchi
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0301 basic medicine ,business.industry ,Cancer ,Hematology ,Pharmacology ,medicine.disease ,Controlled release ,Flutamide ,03 medical and health sciences ,chemistry.chemical_compound ,030104 developmental biology ,0302 clinical medicine ,chemistry ,Oncology ,030220 oncology & carcinogenesis ,medicine ,business - Published
- 2016
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6. Platelet count and mean platelet volume are associated with not only bone, soft tissue, and lymph node metastases but also with malignant pleural effusion in lung cancer patients
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K Ueda, Y Ozaki, M Ohuchi, and S Inoue
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0301 basic medicine ,Cancer Research ,medicine.medical_specialty ,Pathology ,Lung Neoplasms ,Bone Neoplasms ,Soft Tissue Neoplasms ,Gastroenterology ,03 medical and health sciences ,0302 clinical medicine ,Internal medicine ,medicine ,Malignant pleural effusion ,Humans ,Platelet ,Mean platelet volume ,Lung cancer ,Lymph node ,Survival analysis ,Retrospective Studies ,Thrombocytosis ,business.industry ,Platelet Count ,Cancer ,medicine.disease ,Prognosis ,Survival Analysis ,Pleural Effusion, Malignant ,030104 developmental biology ,medicine.anatomical_structure ,Oncology ,030220 oncology & carcinogenesis ,Lymphatic Metastasis ,Lymph Nodes ,business ,Mean Platelet Volume - Abstract
An increased platelet count is often observed in lung cancer patients. Whether and how the platelets affect cancer progression have yet to be established. The aim of the study was to investigate the involvement of the platelet count and mean platelet volume (MPV) in the prognosis and progression of lung cancer patients. This retrospective study included 146 patients with newly diagnosed primary lung cancer. The platelet count and MPV were measured before invasive diagnostic procedures and treatment. These platelet indices, overall survival of the patients, and tumor metastases for each organ were analyzed. On Kaplan-Meier survival analysis, the overall survivals of patients with platelet counts ≤ 244.0 × 109/L or MPV > 9.7 fL were longer than those of patients with platelet counts > 244.0 × 109/L or MPV ≤ 9.7 fL. Cox regression analysis showed that poor performance status, increased platelet count, and increased C-reactive protein were independent prognostic factors. The platelet indices were associated with metastases to bone, soft tissue, and lymph node, in addition to malignant pleural effusion. Increased platelet count and decreased MPV were unfavorable prognostic factors for patients with lung cancer, and they were involved in bone, soft tissue, and lymph node metastases and malignant pleural effusion.
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- 2016
7. Evaluation of heat flux from the plasma flow by using calorimeter in the GAMMA 10/PDX end-cell
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Naomichi Ezumi, Hiroto Matsuura, Takayuki Yokodo, K. Tsumura, M. Sakamoto, G. Lee, M. M. Islam, Kazuya Ichimura, Md. Shahinul Islam, M. Ohuchi, K. Fukui, Tsuyoshi Kariya, R. Minami, T. Imai, and Yousuke Nakashima
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Physics ,Nuclear physics ,Plasma flow ,Heat flux ,Time response ,Critical heat flux ,Astrophysics::High Energy Astrophysical Phenomena ,Heat transfer ,Mechanics ,Electron cyclotron resonance ,Calorimeter ,Power (physics) - Abstract
In this paper, detailed results of the heat flux measurements are presented and the improvement of heat flux evaluation method is also discussed. We measured the heat flux in the case that additional heating with electron cyclotron resonance heating (ECRH). The heat flux reaches about 17 MW/m2 in the case with ECRH power 380kW. It is found that solving one-dimensional inverse heat conduction problems provides a possibility of improving time response of the heat flux measurement under the condition of changing heat flux in 20Hz.
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- 2016
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8. Study of plasma behavior during impurity injection in the end-cell of GAMMA 10/PDX by fluid code
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Kazuya Ichimura, Md. Shahinul Islam, Yousuke Nakashima, Naomichi Ezumi, K. Shimizu, Akiyoshi Hatayama, Mizuki Sakamoto, K. Fukui, Ryoko Tatsumi, M. M. Islam, T. Imai, M. Ohuchi, G. Lee, and Takayuki Yokodo
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Electron density ,Heat flux ,Plasma parameters ,Impurity ,Chemistry ,Ion density ,Analytical chemistry ,Electron temperature ,Electron ,Plasma ,Atomic physics - Abstract
The effect of neutral Ar injection on the plasma parameters is investigated numerically by using a multi-fluid code in this research. Reduction of electron and ion temperature has been observed according to the increment in injected neutral Ar density. The heat flux on the target plate has been also reduced with the increasing of injected neutral Ar density. For Ar: 2.0 × 1018 m−3 injection, electron temperature on the target plate reduced to about 1.5 eV. Increase in electron and ion density has been observed at lower injected Ar density. However, at higher Ar injection, electron density and ion density goes to be saturated. These outcomes indicate that the plasma in the end region approaches towards the plasma detachment state.
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- 2016
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9. Study of beam-material interaction by using hydrogen ion beam
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Kazuya Ichimura, K. Ohkawa, Takayuki Yokodo, Shinji Nagata, Yousuke Nakashima, M. M. Islam, M. Ohuchi, K. Fukui, K. Shimizu, Md. Shahinul Islam, and M. Arai
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Interaction studies ,Hydrogen ion ,Ion beam deposition ,Ion beam ,Calorimeter (particle physics) ,Chemistry ,Physics::Accelerator Physics ,Tungsten target ,Atomic physics ,Beam (structure) ,Magnetic field - Abstract
In this research, the effect of beam convergence with magnetic field of GAMMA 10/PDX has been investigated. The hydrogen ion beam is injected to the tungsten target under the various strength of magnetic field. The spatial distribution of emission light and rising temperature of the target are measured with a fast camera and a calorimeter, respectively. Effectiveness of beam convergence due to the magnetic field expansion is evaluated from the viewpoint of beam-material Interaction studies.
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- 2016
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10. Characteristics of SMBI fueling with laval nozzle in GAMMA 10 based on experimental and simulation results
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M. Hirata, Junko Kohagura, K. Hosoi, Md. Shahinul Islam, M. M. Islam, Masayuki Yoshikawa, G. Lee, M. Ohuchi, Shinji Kobayashi, Nobuhiro Nishino, K. Shimizu, Kazuya Ichimura, M. Arai, Yousuke Nakashima, Ryuya Ikezoe, K. Fukui, Mizuki Sakamoto, Takayuki Yokodo, T. Imai, and Makoto Ichimura
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Full width at half maximum ,Chemistry ,Nozzle ,Analytical chemistry ,Particle ,Light emission ,Supersonic speed ,Diffusion (business) ,Plenum space ,Computational physics - Abstract
Results of supersonic molecular bean injection (SMBI) with Laval nozzle has been carried out in the GAMMA 10 tandem mirror. The neutral transport during SMBI was investigated by the two-dimensional image of the light emission captured by the high-speed camera. We used the value of full width at half maximum (FWHM) of the distribution of emission intensity as an index of neutral transport. The FWHM value decreases with the increase of the plenum pressure which indicates that the particle diffusion was more convergent at high plenum pressure. Fully three-dimensional neutral transport simulation using a Monte-Carlo code DEGAS is applied to SMBI experiment and simulation results qualitatively explained the experimental results.
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- 2016
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11. Study of the impurity transport by injecting the gas to D-module in GAMMA 10/PDX
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Kunpei Nojiri, Md. Shahinul Islam, A. Terakado, Yousuke Nakashima, Takayuki Yokodo, Masayuki Yoshikawa, M. M. Islam, T. Imai, K. Fukui, M. Ohuchi, K. Shimizu, Kazuya Ichimura, Mizuki Sakamoto, and Naomichi Ezumi
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law ,Chemistry ,Impurity ,Ionization ,Divertor ,Time evolution ,Electron temperature ,Plasma ,Emission spectrum ,Atomic physics ,Spark plug ,Quantitative Biology::Cell Behavior ,law.invention - Abstract
In this study, spectroscopic measurement at the plug/barrier-cell, near the midplane in GAMMA 10/PDX was carried out for the first time. From the comparison of the spectroscopic data measured in the end-cell and plug/barrier-cell, transport of impurities injected to divertor simulation module in the end-cell is investigated. It was found that Ne hardly ionized at both observation points. On the other hand, N2 dissociated and ionized before reaches or at the plug/barrier-cell while emission spectrum derived from N2 was dominated at the end-cell. From the comparison of the emission spectrum at the end-cell and plug/barrier-cell, it suggests that Ne was more likely to transport toward upstream region through the plasma than N2. Time evolution of specific emission spectra, electron temperature and density suggests the reduction of the impurity transport during ECH pulse.
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- 2016
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12. Prognostic and clinical impact of sarcopenia in esophageal squamous cell carcinoma
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K, Harada, S, Ida, Y, Baba, T, Ishimoto, K, Kosumi, R, Tokunaga, D, Izumi, M, Ohuchi, K, Nakamura, Y, Kiyozumi, Y, Imamura, M, Iwatsuki, S, Iwagami, Y, Miyamoto, Y, Sakamoto, N, Yoshida, M, Watanabe, and H, Baba
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Male ,Sarcopenia ,Esophageal Neoplasms ,Anastomotic Leak ,Chemoradiotherapy ,Middle Aged ,Prognosis ,Esophagectomy ,Survival Rate ,Postoperative Complications ,Japan ,Carcinoma, Squamous Cell ,Humans ,Female ,Esophageal Squamous Cell Carcinoma ,Lymph Nodes ,Muscle, Skeletal ,Tomography, X-Ray Computed ,Aged ,Neoplasm Staging ,Retrospective Studies - Abstract
Recently, depletion of skeletal muscle mass (sarcopenia) has been linked to poor prognosis in several types of cancers, but has not been investigated in esophageal squamous cell carcinoma (ESCC). This retrospective study investigates the relationship between sarcopenia and clinical outcome in ESCC patients treated by surgical resection or definitive chemoradiation therapy (dCRT). The study was retrospectively conducted in a single academic hospital in Kumamoto, Japan, and involved 325 ESCC patients (256 surgical cases and 69 dCRT cases) treated between April 2005 and April 2011. Skeletal muscle mass was quantified by radiologic measures using standard computed tomography scans. The skeletal muscle tissue in the 325 ESCC patients was distributed as follows: mean: 47.10; median: 46.88; standard deviation (SD): 7.39; range: 31.48-71.11; interquartile range, 46.29-47.90. Skeletal muscle tissue was greater in male patients than in female patients (P0.0001), but was independent of other clinical and tumor features. Sarcopenia was not significantly associated with overall survival (log rank P = 0.54). Lymph node involvement significantly altered the relationship between sarcopenia and survival rate (P for interaction = 0.026). Sarcopenia significantly reduced the overall survival of patients without lymph node involvement (log rank P = 0.035), but was uncorrelated with overall survival in patients with lymph involvement (log rank, P = 0.31). The anastomosis leakage rate was significantly higher in the sarcopenia group than in the non-sarcopenia group (P = 0.032), but other surgical complications did not significantly differ between the two groups. Sarcopenia in ESCC patients without lymph node involvement is associated with poor prognosis, indicating sarcopenia as a potential biomarker for identifying patients likely to experience an inferior outcome. Moreover, sarcopenia was associated with anastomosis leakage but no other short-term surgical outcome.
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- 2015
13. Liposomal nanoparticles for photomagnetic controlled drug release with radical pair mechanism
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Hidenori Nakagawa and M. Ohuchi
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Oncology ,business.industry ,Drug release ,Nanoparticle ,Medicine ,Hematology ,business ,Combinatorial chemistry ,Mechanism (sociology) - Published
- 2017
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14. Expression of OX40 and OX40 ligand (gp34) in the normal and myasthenic thymus
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M. Ohuchi, Kazuo Fujihara, Tetsuya Nagata, Y. Itoyama, J. Onodera, Kazuo Sugamura, and Naoto Ishii
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medicine.medical_specialty ,education.field_of_study ,Thymoma ,medicine.diagnostic_test ,Immunocytochemistry ,Germinal center ,General Medicine ,T lymphocyte ,Biology ,medicine.disease ,Myasthenia gravis ,Flow cytometry ,OX40 ligand ,Endocrinology ,Neurology ,Internal medicine ,medicine ,Neurology (clinical) ,education ,CD8 - Abstract
Objectives - To examine the expression of OX40, an activated memory T-cell marker, and its ligand (OX40L), a set of molecules for T-cell-B-cell interaction, and other lymphocyte activation markers in the thymuses of myasthenia gravis (MG) and controls. Material and methods - We studied the expression of OX40, OX40L, IL-2Ra and HLA-DR in the thymic tissues of MG and controls using immunocytochemistry and flowcytometry. Results - In both hyperplastic thymus of MG and control thymus, OX40 + cells were scattered mainly in the medulla with much fewer OX40L + cells being distributed in the corticomedullary junctions. IL-2Ra and HLA-DR were expressed in the medulla at higher frequencies as compared with OX40 in controls as well as MG. In contrast, the numbers of OX40 + cells around the germinal centers (GC) were significantly greater than those of control thymuses, and some mononuclear cells in GC were OX40L + . A considerable number of OX40 + cells were seen in the thymic tissues adjacent to thymomas. OX40 + cells were CD4 + CD8 or CD4 + CD8 + and were mostly HLA-DR . (The coexpression of OX40 and IL-2Ra on activated CD4 + T cells was previously reported.) Conclusion - OX40, expressed in a fraction of activated CD4 + T cells, may be upregulated in thymic tissues adjacent to GC and thymoma in MG, and OX40 may interact with OX40L in GC to enhance anti-acetylcholine receptor antibody production in MG.
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- 2000
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15. Field-emission properties of diamond grains grown on textured Fe/Si substrates
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Kenji Hirakuri, Nobuki Mutsukura, T. Kurata, Gernot Friedbacher, and M. Ohuchi
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Field electron emission ,Materials science ,Scanning electron microscope ,Sputtering ,Material properties of diamond ,engineering ,Nucleation ,Analytical chemistry ,General Physics and Astronomy ,Diamond ,engineering.material ,Thin film ,Isotropic etching - Abstract
Diamond grains were produced by the hot-filament chemical-vapor deposition technique using a mixture of CH4/H2 as the synthesis gas. The Si substrates were textured (random pyramids) by chemical etching before growth of diamond grains, because emission of electrons is facilitated at the top of the pyramids. In order to increase the diamond nucleation density, an iron thin film (Fe) was deposited on the textured Si substrate by a radio-frequency plasma sputtering technique. Moreover, partial iron thin films (20% surface coverage) were fabricated for application as field emitter displays using a metal mask. The relationship between the nucleation density and the thickness of the iron films has been investigated by scanning electron microscopy (SEM). The samples were placed in a high-vacuum chamber with a pumping system and the emission current was measured as a function of the applied voltage. The voltage–current (V–I) characteristics were estimated for the field emitter. In order to etch nondiamond components, these samples were etched by O2 and CF4 plasmas. SEM observation revealed that diamond growth is concentrated at the textured Fe/Si area. The nucleation density was 107 cm−2 on the textured Fe/Si area. On the plain textured Si substrate diamond growth could not be observed. Numberless tips were observed on the Fe/Si area after etching. The V–I characteristics revealed a current 10−8 A at an applied voltage of 1.8 kV. The V–I characteristics could be enhanced by using the textured Fe/Si substrate.
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- 2000
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16. Measurement of neutral gas pressure in the D-module of GAMMA 10/PDX by using ASDEX type fast ionization gauge
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Kazuya Ichimura, M. Fukumoto, Yousuke Nakashima, Masayuki Yoshikawa, A. Terakado, Md. Shahinul Islam, Kunpei Nojiri, K. Fukui, M. M. Islam, M. Ohuchi, Mizuki Sakamoto, Naomichi Ezumi, and K. Shimizu
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010302 applied physics ,Materials science ,Hydrogen ,Divertor ,chemistry.chemical_element ,Atmospheric-pressure plasma ,Plasma ,Gauge (firearms) ,01 natural sciences ,010305 fluids & plasmas ,law.invention ,Pressure measurement ,Heat flux ,chemistry ,Physics::Plasma Physics ,law ,Ionization ,0103 physical sciences ,Atomic physics ,Instrumentation - Abstract
In the divertor simulation experiments in the GAMMA 10/PDX tandem mirror, pressure of the neutral gas was investigated by using a fast ionization gauge. The gauge was absolutely calibrated for hydrogen gas by using a capacitance manometer. Change of the gauge sensitivity due to the magnetic field of GAMMA 10/PDX was also evaluated. The typical gas pressure measured in detached plasma experiments was 0.1–10 Pa. The degree of plasma detachment determined from the reduction of heat flux was enhanced as the gas pressure increases. Rapid increase of the gas pressure under the plasma flow was also observed.
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- 2016
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17. Effect of Laval Nozzle in the GAMMA 10 SMBI Experiments
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K. Fukui, A. Terakado, Ryuya Ikezoe, Junko Kohagura, K. Hosoi, Nobuhiro Nishino, Yousuke Nakashima, Md. Shahinul Islam, Masayuki Yoshikawa, Makoto Ichimura, Tsuyoshi Imai, Yuichiro Nakano, Mafumi Hirata, Xiaolong Wang, M. M. Islam, M. Ohuchi, K. Shimizu, Mizuki Sakamoto, Shinji Kobayashi, and Kazuya Ichimura
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Physics ,Optics ,High-speed camera ,business.industry ,0103 physical sciences ,Nozzle ,010306 general physics ,Condensed Matter Physics ,business ,01 natural sciences ,010305 fluids & plasmas - Abstract
Gas fueling by supersonic molecular beam injection (SMBI) has been performed at the central-cell in GAMMA 10. The results of SMBI experiment with plenum pressure from 0.3 MPa to 2.0 MPa were obtained using a laval nozzle. The distribution of the emission intensity during SMBI was investigated by the 2-dimensional image captured by the fast camera as an index of the neutral transport. The experimental results indicates that the effect of the laval nozzle reduces the dispersion of injected hydrogen molecules in the peripheral region. In this paper, we also studied the line density at the central-cell (NLcc) and Hα emission intensity during SMBI. Comparison between SMBI and conventional gas puffing is also discussed from the view point of the fueling efficiency.
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- 2016
18. Study of the Axial Ion Confinement Time for High Particle Flux Operations of GAMMA 10/PDX
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Naomichi Ezumi, Md. Shahinul Islam, K. Shimizu, M. M. Islam, M. Ohuchi, Mizuki Sakamoto, Tsuyoshi Imai, K. Fukui, K. Ichimura, Makoto Ichimura, Yousuke Nakashima, Masayuki Yoshikawa, S. Sumida, Mafumi Hirata, and Ryuya Ikezoe
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Physics ,020209 energy ,02 engineering and technology ,Condensed Matter Physics ,01 natural sciences ,010305 fluids & plasmas ,Ion ,Nuclear physics ,Physics::Plasma Physics ,0103 physical sciences ,Physics::Space Physics ,0202 electrical engineering, electronic engineering, information engineering ,Atomic physics ,Particle flux - Abstract
Characteristics of axial plasma confinement in recent high-density mode of GAMMA 10/PDX tandem mirror is reported in this paper. The parameter of the end-loss ion flux is an important issue in the divertor simulation studies in GAMMA 10/PDX. With an ICRF heating in the anchor-cells of the machine, large increase in the electron line-density in the central-cell (NLCC) and the end-loss particle flux were observed. The behavior of the electron line density, plasma temperature and the amount of end-loss ion flux during the experiments suggested that the mechanism of the axial ion loss was changed due to the increase of ion collision frequency. In contrast with the standard operations of GAMMA 10/PDX, plasma parameters in recent high-density operations stays in the range of high collision frequency. In such collisional plasma, the end-loss ion particle flux show linear dependence on the plasma density instead of the parabolic dependence expected in plasmas of low collision frequency. In the high collision frequency plasma, it is notable that plasma potential φ largely changes the dependence of the particle flux on the plasma density.
- Published
- 2016
19. Study of an activated carbon by the ESR triple-modulation spectrum method
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K. Sogabe, K. Hukao, Ichiro Miyagawa, and M. Ohuchi
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musculoskeletal diseases ,Chemistry ,Thermal motion ,General Physics and Astronomy ,chemistry.chemical_element ,Photochemistry ,Laser linewidth ,Modulation spectrum ,medicine ,Physical and Theoretical Chemistry ,Absorption (electromagnetic radiation) ,Homogeneous broadening ,Carbon ,Activated carbon ,medicine.drug - Abstract
In the study of an activated carbon with the ESR triple-modulation spectroscopic method, a thermal motion of the radical was observed, while no such motion was detected in the raw carbon. Moreover, the activation process of the carbon increased drastically the linewidth of the ESR absorption, converting its nature from a homogeneous broadening to an inhomogeneous one.
- Published
- 1994
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20. A Si bipolar 5-Gb/s 8:1 multiplexer and 4.2-Gb/s 1:8 demultiplexer
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M. Ohuchi, K. Matsumoto, A. Sawairi, T. Tashiro, S. Hatakeyama, T. Okamura, F. Kuniba, and Kikuo Okuyama
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Engineering ,Demultiplexer ,business.industry ,Circuit design ,Electrical engineering ,Hardware_PERFORMANCEANDRELIABILITY ,Emitter-coupled logic ,Chip ,Multiplexer ,law.invention ,Capacitor ,Parasitic capacitance ,law ,Hardware_INTEGRATEDCIRCUITS ,Electrical and Electronic Engineering ,Resistor ,business - Abstract
Conventionally, ultrahigh-speed 2:1 multiplexers and 1:2 demultiplexers have been demonstrated with HBTs, MESFETs, and Si BJTs. Multiplexers and demultiplexers with a high number of bits are desirable to simplify a system. Si bipolar circuits and package design technology for a 5-Gb/s 8:1 multiplexer and a 4.2 Gb/s 1:8 demultiplexer are described. These multigigabit LSIs have been achieved mainly by switching current optimization within the limit of keeping a maximum unity unilateral gain frequency (f/sub max/), by careful circuit and layout design considering accurate parasitic capacitance modeling, and by using a high-speed Si bipolar technology. These LSIs are housed in a newly developed 56-pin six-layer ceramic package with chip resistors for ECL termination and chip capacitors for good RF grounding. >
- Published
- 1992
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21. A Si bipolar 28-GHz dynamic frequency divider
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Hisashi Takemura, M. Ohuchi, G. Uemaru, C. Ogawa, T. Morikawa, Tsutomu Tashiro, and M. Kurisu
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Frequency synthesizer ,Engineering ,business.industry ,Frequency multiplier ,Electrical engineering ,Current divider ,Cutoff frequency ,Frequency divider ,Phase-locked loop ,Optoelectronics ,Ka band ,Electrical and Electronic Engineering ,business ,Monolithic microwave integrated circuit - Abstract
A dynamic frequency divider applying the regenerative frequency division principle has been developed. A spiral inductor on the silicon substrate used as a load is characterized, and an improved one-port model with the substrate resistance is discussed. A 1/16 frequency divider was implemented with a silicon bipolar technology with a cutoff frequency of 40 GHz. The operation frequency range was 11.8-28.1 GHz, covering the Ka band (18-26.5 GHz). The inductive load has improved the maximum operation frequency by 7%, compared with a conventional circuit. Complemented with a 21-GHz static frequency divider previously reported by the authors, the whole microwave frequency range up to 26.5 GHz has been completely covered with the silicon bipolar technology. The maximum operation frequency of a silicon MMIC has been extended to the millimeter-wave frequency region for the first time. >
- Published
- 1992
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22. A Si bipolar 21-GHz/320-mW static frequency divider
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Hisashi Takemura, M. Ohuchi, M. Kurisu, M. Sugiyama, A. Sawairi, and Tsutomu Tashiro
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L band ,Frequency response ,Engineering ,business.industry ,Transistor ,Electrical engineering ,Hardware_PERFORMANCEANDRELIABILITY ,Current divider ,Ku band ,Cutoff frequency ,law.invention ,Frequency divider ,Hardware_GENERAL ,law ,Hardware_INTEGRATEDCIRCUITS ,Electrical and Electronic Engineering ,business ,Microwave - Abstract
A silicon bipolar divide-by-eight static frequency divider was developed. A state-of-the-art advanced borosilicate-glass self-aligned (A-BSA) transistor technology that has a cutoff frequency of 40 GHz at V/sub ce/=1 V was applied. Optimum circuit and layout designs were carried out for high-speed/low-power operation. The single-ended input realized by an on-chip metal-insulator-metal (MIM) capacitor makes it easy to use in microwave applications. Ultrahigh-speed operation, up to 21 GHz, was realized, with 320-mW power dissipation from a single +5-V supply. The static frequency divider is a suitable prescaler for phase-locked oscillators (PLOs), completely covering microwave frequencies from L band through Ku band (1-18 GHz). >
- Published
- 1991
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- View/download PDF
23. Study of Heat and Particle Flux in the Case of Gas Injection in the D-Module of GAMMA 10/PDX
- Author
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Naomichi Ezumi, Hiroto Matsuura, K. Shimizu, K. Fukui, Mizuki Sakamoto, K. Ichimura, Yousuke Nakashima, Tsuyoshi Imai, Md. Shahinul Islam, Kunpei Nojiri, M. M. Islam, M. Ohuchi, and A. Terakado
- Subjects
Nuclear physics ,Materials science ,Heat flux ,Physics::Plasma Physics ,0103 physical sciences ,D-module ,010306 general physics ,Condensed Matter Physics ,Particle flux ,01 natural sciences ,010305 fluids & plasmas - Abstract
This research investigated the radiation cooling mechanism and formation of detached plasma in the case of gas injection in the D-module of GAMMA 10/PDX. In GAMMA 10/PDX, divertor simulation experiments have been started by using a divertor simulation experimental module (D-module). A V-shaped target made of tungsten has been installed in this module. In order to understand the effect of impurity injection into divertor simulation experimental module, we injected H2 and Ar gases to the D-module and measured the heat flux and ion flux. According to the increase of gas injection, reduction of ion and heat fluxes have been observed. In the Ar injection experiments, H2 gas has been injected simultaneously to examine the effect of molecular process on detached plasma formation. In this case, both the heat flux and ion flux are drastically reduced. These results indicate radiation cooling and formation of detached plasma due to gas injection. Simultaneous injection of noble gas and hydrogen gas showed the most effective results on detached plasma generation.
- Published
- 2016
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24. Design and use of a gridded probe in a low‐pressure rf argon discharge
- Author
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M. Ohuchi, S. G. Ingram, and B. M. Annaratone
- Subjects
Argon ,Materials science ,Plasma parameters ,chemistry.chemical_element ,Plasma ,symbols.namesake ,chemistry ,Physics::Plasma Physics ,Secondary emission ,symbols ,Langmuir probe ,Electron temperature ,Plasma diagnostics ,Electric discharge ,Atomic physics ,Instrumentation - Abstract
Low‐pressure rf discharges can be investigated experimentally using many diagnostic techniques. In many cases the simple Langmuir probe can be used to make reliable measurements of basic plasma parameters. In the work reported here, this technique has been extended by employing a gridded Langmuir probe in a parallel‐plate rf discharge for the first time. Design considerations and construction of the probe are discussed. It was found that optimum performance could be achieved using a construction based on two independent grids with a nonzero potential difference between them. The probe was used to measure plasma parameters in a low‐pressure argon discharge excited at 13.56 MHz between two planar parallel electrodes. Results obtained for different probe orientations along the discharge axis show the electron energy distribution to be approximately Maxwellian in the plasma bulk. However, there is evidence for anisotropy in the electron energy distribution in the region of the plasma nearest to the driven electrode. In fact the high‐energy tail observed can be attributed to secondary electron emission from the electrode surface.
- Published
- 1990
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25. How do the polycyclic aromatic hydrocarbons approach infinity?
- Author
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Ying-Duo Gao, Haruo Hosoya, K. Chida, H. Kumazaki, and M. Ohuchi
- Subjects
chemistry.chemical_compound ,chemistry ,Chemical physics ,General Chemical Engineering ,Dimer ,media_common.quotation_subject ,Density of states ,General Chemistry ,Photochemistry ,Infinity ,Electronic properties ,media_common - Abstract
Various topological factors governing the electronic properties of infinitely large periodic polycyclic benzenoids are analyzed graph-theoretically by drawing the density of states (DS). The existence or non-existence of NBMO's in the hypothetical cyclic dimer of the network are shown to be crucial for the profile of DS.
- Published
- 1990
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26. Cavity Effects on the Bearing Capacity of Footing Foundations and the Calculation Method
- Author
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M. Kiyosumi, M. Ohuchi, O. Kusakabe, and F. L. Peng
- Subjects
business.industry ,Bearing capacity ,Structural engineering ,business ,Geology - Published
- 2006
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27. Numerical analysis of pile axial loading test on Ryukyu calcareous sediments
- Author
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M. Kiyosumi, O. Kusakabe, F. L. Peng, N Umeda, and M. Ohuchi
- Subjects
Numerical analysis ,Geotechnical engineering ,Test (biology) ,Pile ,Calcareous ,Geology - Published
- 2005
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- View/download PDF
28. Analytical solutions of surface potential distribution on thin insulators having grounded backing conductor and their applications to electrostatic characterisation
- Author
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A. Ohsawa and M. Ohuchi
- Subjects
Surface (mathematics) ,Materials science ,Distribution (number theory) ,Condensed matter physics ,Geometry ,Conductor - Published
- 2004
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29. Improvement of crystal quality of cubic GaN film using AlN/GaN ordered alloy on GaAs[100] by plasma assisted molecular beam epitaxy
- Author
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A. Shigemori, Ryuhei Kimura, M. Ohuchi, K. Ishida, J. Shike, and Kiyoshi Takahashi
- Subjects
Materials science ,business.industry ,Alloy ,Hexagonal phase ,engineering.material ,Crystal ,Metastability ,Monolayer ,engineering ,Optoelectronics ,business ,Layer (electronics) ,Stoichiometry ,Molecular beam epitaxy - Abstract
Metastable cubic-GaN (c-GaN) is expected to have many advantages in physical properties over those of the hexagonal phase. Improvement of (AlN)/sub m/(GaN)/sub n/ ordered alloy was achieved by optimizing the nitridation conditions. (m and n represent the number of monolayers in each layer). The ordered alloy is used for uniform effective Al molar content control, which can be achieved by varying the ratio of each layer thickness. This process makes it is easy to maintain high quality stoichiometric growth for extended periods because all constituent layers are binary materials.
- Published
- 2003
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30. A Si bipolar 28 GHz dynamic frequency divider
- Author
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M. Kurisu, G. Uemaru, M. Ohuchi, C. Ogawa, H. Takemura, T. Morikawa, and T. Tashiro
- Published
- 2003
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31. Curious controlled release of flutamide-related escape products under exposure to magnetic fields
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M. Ohuchi, Hidenori Nakagawa, H. Kawase, and S. Ueno
- Subjects
Liposome ,business.industry ,Vesicle ,Hematology ,Controlled release ,chemistry.chemical_compound ,Membrane ,Oncology ,Biochemistry ,chemistry ,Dipalmitoylphosphatidylcholine ,Phosphatidylcholine ,Drug delivery ,Biophysics ,Medicine ,business ,Lipid bilayer - Abstract
Introduction: Flutamide (FM: 2-methyl-N-[4-nitro-3-(trifluoromethyl)phenyl]propanamide) is a non-steroidal anti-cancer drug, and is widely applied to recent drug delivery technologies. Several reports also have shown the photoreactivity of FM in phospholipid bilayer vesicles (liposomal membranes). However, there are no reported studies of the application of radical pair mechanisms to drug release controlling of FM-incorporated liposomal carriers under exposure to magnetic fields. In this study, we investigated magnetic controls of the carriers for an advantageous release of flutamide-related escape products. Materials & methods: Egg yolk phosphatidylcholine (PC) or Dipalmitoylphosphatidylcholine (DPPC) was used as the lipid component of liposomes. FM-incorporated multilamellar vesicles (FM-MLVs) were prepared according to the previous method [ 1 ]. FM-incorporated small unilamellar vesicles (FM-SUVs) were prepared by the membrane filtration method [ 2 ]. All operations were carried out under nitrogen. FM-related escape products were monitored measuring the delayed fluorescence (ex. 530 nm, em. 890 nm) of the products. The magnetic field strength was set up in the range of 50–150 mT. Results: For measurements of magnetic field effects on release of FM-related escape products, the decrease in the products is due to S-T level intersystem crossing on radical pair mechanisms. When PC was used as the lipid component of the FM-SUVs, competition between magnetic field effects and the product release was observed depending on the field strength. In the case of the FM-SUVs prepared from DPPC lipid molecules, the increase in the product release was relatively faithful to S-T Intersystem. Conclusions: From these findings, the product release is deemed not to be caused by only the radical pair mechanisms. However, the tests observing the magnetic field effects might provide useful in formation on drug targeting. Acknowledgement: A Grant-in-Aid for Encouragement of Scientists (No.26930033) from the Japan Society for the Promotion of Science (JSPS).
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- 2015
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32. Liposomal drug delivery with anti-cancer flutamide-related radical pair system under exposure to pulsating electromagnetic fields
- Author
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M. Ohuchi, Hidenori Nakagawa, S. Ueno, and H. Kawase
- Subjects
Liposome ,Electromagnetics ,Singlet oxygen ,business.industry ,Vesicle ,Membrane structure ,Hematology ,Fluorescence ,chemistry.chemical_compound ,Membrane ,Oncology ,chemistry ,Drug delivery ,Biophysics ,Medicine ,business - Abstract
Background: The process of liposomal drug delivery is generally understood based on the destabilization of liposomal membranes in the target tissue. On the other hand, the membrane structure must be stable enough in the bloodstream for the reduction of side effects. Previously, we demonstrated the design of paramagnetic liposomes modified with 2, 2'-azobis(2, 4-dimethylvaleronitrile) (AMVN) to show the broad potential opportunities in drug delivery systems [ 1 ]. This finding can be expected to reveal new knowledge for resolving important clinical problems. In our present research, we considered examining electromagnetic effects of combined AC/DC fields to measure the physicochemical changes of flutamide-entrapped liposomal membranes modified with reactive oxygen species. Materials & methods: For the preparation of multilamellar vesicles (MLVs), each dry film composed of various molar ratios of phospholipids, photosensitizers and anti-cancer flutamide was hydrated by vortexing them with some appropriate buffer solutions. Each of the MLV dispersions was transferred to a Mini-Extrudor (Avanti Polar Lipids, Inc.) to produce small unilamellar vesicles (SUVs). Under exposure to electromagnetic fields, the photosensitizers and flutamide in the liposomal membrane were excited by a laser emission wavelength of 335 nm. In order to compare the effects of the pulsating electromagnetic fields on the behaviour of the model membranes, we measured the spectral changes as well as the delayed fluorescence with absorbance at 380 and 290 nm after the emission. Results: In the results of our measurements, we found the possibility that a high frequency of up to 2 MHz affects the radical pair mechanisms in the process of membrane modifications induced by excited singlet oxygen. In addition, the electromagnetic effects may make a lot of advantageous pores in the modified membrane to release the flutamide-related cage products. Conclusions: We strongly propose a new drug release technology using these liposomes equipped with electromagnetic controls. acknowledgement: A Grant-in-Aid for Encouragement of Scientists (No.26930033) from the Japan Society for the Promotion of Science (JSPS).
- Published
- 2015
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33. [Pericardiectomy for post-coronary artery bypass grafting constrictive pericarditis; strategy for safe and complete pericardiectomy]
- Author
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T, Shibuya, M, Ohmi, S, Kawamoto, M, Shimizu, M, Ohuchi, Y, Sawamura, S, Kikuchi, T, Ito, and K, Takase
- Subjects
Male ,Imaging, Three-Dimensional ,Postoperative Complications ,Pericardiectomy ,Myocardial Ischemia ,Pericarditis, Constrictive ,Humans ,Ultrasonography, Doppler ,Coronary Artery Bypass ,Middle Aged ,Tomography, X-Ray Computed - Abstract
Surgery for constrictive pericarditis after coronary artery bypass grafting (CABG) needs complete pericardiectomy without injury to bypass grafts. We performed pericardiectomy for post-CABG constrictive pericarditis 15 months after the first surgery. Preoperative multislice helical 3-dimensional computed tomography (CT) clearly demonstrated the patent bypass grafts and anatomical relationship between grafts and surrounding organs. Among surgical approaches, we chose bilateral thoracotomy to avoid injury to the bypass grafts and to obtain a good surgical exposure, especially for pericardiectomy of the left side of the heart. Additionally, with the use of intraoperative doppler ultrasound blood flowmetry, we could safely achieve complete pericardiectomy. We conclude that the combined application of 3-dimensional CT, bilateral thoracotomy and doppler ultrasound blood flowmetry was a supreme strategy for the operation of constrictive pericarditis after CABG.
- Published
- 2002
34. Three-dimensional shape modeling with extended hyperquadrics
- Author
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T. Saito and M. Ohuchi
- Subjects
Implicit function ,Mathematics::Complex Variables ,business.industry ,Generalization ,Computer science ,Geometric shape ,Solid modeling ,Ellipsoid ,Synthetic data ,Distance measures ,Computer vision ,Mathematics::Differential Geometry ,Artificial intelligence ,business ,Representation (mathematics) ,Algorithm - Abstract
The shape representation and modeling based on implicit functions have received considerable attention in computer vision literature. In this paper, we propose extended hyperquadrics, as a generalization of hyperquadrics developed by Hanson, for modeling global geometric shapes. The extended hyperquadrics can strengthen the representation power of hyperquadrics, especially for the object with concavities. We discuss the distance measures between extended hyperquadric surfaces and given data set and their minimization to obtain the optimum model parameters. We present several experimental results for fitting extended hyperquadrics to 3D real and synthetic data. We demonstrate that extended hyperquadrics can model more complex shapes than hyperquadrics, maintaining many desirable properties of hyperquadrics.
- Published
- 2002
- Full Text
- View/download PDF
35. [Management of myasthenia gravis in association with thymoma]
- Author
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M, Shimizu, M, Ohuchi, M, Ohmi, and T, Nakame
- Subjects
Adult ,Male ,Thymoma ,Remission Induction ,Thymus Neoplasms ,Middle Aged ,Prognosis ,Thymectomy ,Combined Modality Therapy ,Treatment Outcome ,Myasthenia Gravis ,Humans ,Female ,Sex Distribution ,Aged ,Retrospective Studies - Abstract
From June 1975 to March 2002, we experienced 339 patients with myasthenia gravis (MG). Ninety-four patients (81 generalized MG and 13 ocular type) had associated with thymoma. Extended thymectomy including thymoma was performed in all patients. The thymomas were classified as stage I (n = 46), II (n = 31), III (n = 14), and IV a (n = 3). Histopathological findings of the thymoma indicated polygonal cell type in 75 cases, mixture of polygonal and spindle cell type in 14, and spindle cell type in 3, respectively. Three cases in stage II, 12 in III, and 3 in IV a received postoperative radiation therapy. Twenty-two patients required prolonged respirator management for respiratory crisis. Complete remission of MG was seen in 15 cases (17%), and good therapeutic results were obtained in 55 cases (58%) with combined corticosteroid therapy. On the other hand, recurrences of the invasive thymoma were seen in 12 cases (13%), and six of them (6%) died of the tumor. In conclusion, early extended thymectomy including thymoma is markedly effective therapy for MG associated with thymoma, although careful attention should be paid for recurrence of the invasive thymoma.
- Published
- 2002
36. [Surgical treatment of aneurysm of the ductus arteriosus in the adult]
- Author
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M, Ohmi, T, Shibuya, S, Kawamoto, M, Shimizu, and M, Ohuchi
- Subjects
Male ,Blood Vessel Prosthesis Implantation ,Aortic Aneurysm, Thoracic ,Humans ,Aorta, Thoracic ,Ductus Arteriosus ,Middle Aged ,Aneurysm ,Ductus Arteriosus, Patent ,Aged - Abstract
Aneurysm of the ductus arteriosus is rare, however, reports on this lesion have increased recently with the progress of thoracic aortic surgery in Japan. We report 3 male cases aged 58, 59, 73 years. Aneurysms and total aortic arch were replaced by artificial graft through median sternotomy using selective cerebral perfusion in 2 cases. Through left posterolateral thoracotomy using deep hypothermia with circulatory arrest, proximal descending thoracic aorta including the aneurysm was replaced in 1 case. Their postoperative courses were uneventful. Surgery for this lesion is safe and various surgical approaches and circulatory supporting methods can be selected depending on the size of aneurysm and associated lesions.
- Published
- 2002
37. [A patient with facioscapulohumeral muscular dystrophy accompanied by myasthenia gravis]
- Author
-
H, Sakuma, S, Shimazaki, H, Saito, and M, Ohuchi
- Subjects
Male ,Treatment Outcome ,Prednisolone ,Myasthenia Gravis ,Humans ,Female ,Cholinesterase Inhibitors ,Middle Aged ,Thymectomy ,Muscular Dystrophy, Facioscapulohumeral ,Aged - Abstract
A patient was a fifty-year-old man, who had a 35 year-history of facioscapulohumeral muscular dystrophy (FSHD). He was admitted to our hospital because of acute progressive weakness involving his lower extremities without any fluctuation in the recent 3 weeks. We clinically followed him for 30 years and he was able to do all daily activities, walked alone, drove a car and climbed stairs with a handrail. His 76-year-old mother had about 60 year-history of FSHD and could walk with support. On admission, neurological examination revealed moderate to marked muscle weakness and atrophy of the face, limb-girdle and all extremities, predominantly in the upper proximal limbs. He could hardly stand and needed a stick for walking. He had no blepharoptosis or ocular movement disturbance, and did not complain of difficulties in swallowing and chewing. CK values and other laboratory data were normal, and serum anti-Jo-1 antibody, anti-SSA/Ro antibody and anticardiolipin IgG antibody were negative. Because EMG examination revealed myopathic changes and an X-ray examination of the lumbar spine was normal. Thus, polymyositis and neurologenic disorders were ruled out. Disturbance in chewing and swallowing, that were uncommon in FSHD, appeared about a month after admission. Repetitive stimulation test revealed typical waning pattern. Edrophonium chloride injection was effective for decreased waning and the clinical symptoms. The titer of serum anti-ACh receptor antibody was 97 nmol/l, confirming the diagnosis of myasthenia gravis. Because of fluctuated dyspnea, thymectomy was done and his condition gradually relieved after administration of corticosteroid and choline esterase inhibitor. From this experience, we learned that we have to consider other neuromuscular disorders, even rare ones, if there existed unusual weakness of underlying muscular dystrophy.
- Published
- 2001
38. [Follow-up study of myasthenia gravis: evaluation of thymectomy in 300 patients]
- Author
-
M, Ohuchi, M, Shimizu, S, Kawamoto, T, Shibuya, M, Ohmi, H, Onodera, and Y, Itoyama
- Subjects
Adult ,Aged, 80 and over ,Male ,Adolescent ,Thymoma ,Remission Induction ,Infant ,Thymus Neoplasms ,Middle Aged ,Thymectomy ,Evaluation Studies as Topic ,Child, Preschool ,Myasthenia Gravis ,Humans ,Female ,Child ,Aged ,Follow-Up Studies - Abstract
From June 1975 to March 1999, 300 patients of myasthenia gravis(MG) have undergone thymectomy. Among these patients, 69 cases were classified as ocular type of MG(including 15 cases with thymoma), and 231 were generalized type of MG(including 86 cases with thymoma). The efficacy of the treatment was investigated by evaluating current patients' life activity, which is classified in 6 groups(Remission, Much Improved, Improved, Unchanged, Worse, and Died). Among the 214 cases without thymoma, Remission was 75, Much Improved was 56, and Improved was 55, namely 86.9% of these cases showed Improved or better. Among 86 cases with thymoma, Remission was 14, Much Improved was 21, and Improved was 32, namely 77.9% of these cases showed Improved or better. We concluded that post-operative outcome of these patients regardless of thymoma were generally satisfactory, but it was necessary to carry out long term careful follow-up.
- Published
- 2001
39. Mini-plasmin found in the epithelial cells of bronchioles triggers infection by broad-spectrum influenza A viruses and Sendai virus
- Author
-
M, Murakami, T, Towatari, M, Ohuchi, M, Shiota, M, Akao, Y, Okumura, M A, Parry, and H, Kido
- Subjects
Male ,Isoflurophate ,Dose-Response Relationship, Drug ,Sequence Homology, Amino Acid ,Blotting, Western ,Cell Membrane ,Molecular Sequence Data ,Bronchi ,Epithelial Cells ,Infections ,Immunohistochemistry ,Peptide Fragments ,Respirovirus ,Rats ,Substrate Specificity ,Viral Envelope Proteins ,Influenza A virus ,Sequence Analysis, Protein ,Animals ,Humans ,Electrophoresis, Polyacrylamide Gel ,Amino Acid Sequence ,Fibrinolysin ,Rats, Wistar ,Lung - Abstract
Extracellular cleavage of virus envelope fusion glycoproteins by host cellular proteases is a prerequisite for the infectivity of mammalian and nonpathogenic avian influenza viruses, and Sendai virus. Here we report a protease present in the airway that, like tryptase Clara, can process influenza A virus haemagglutinin and Sendai virus envelope fusion glycoprotein. This protease was extracted from the membrane fraction of rat lungs, purified and then identified as a mini-plasmin. Mini-plasmin was distributed predominantly in the epithelial cells of the upward divisions of bronchioles and potentiated the replication of broad-spectrum influenza A viruses and Sendai virus, even that of the plasmin-insensitive influenza A virus strain. In comparison with plasmin, its increased hydrophobicity, leading to its higher local concentrations on membranes, and decreased molecular mass may enable mini-plasmin to gain ready access to the cleavage sites of various haemagglutinins and fusion glycoproteins after expression of these viral proteins on the cell surface. These findings suggest that mini-plasmin in the airway may play a pivotal role in the spread of viruses and their pathogenicity.
- Published
- 2001
40. Expression of OX40 and OX40 ligand (gp34) in the normal and myasthenic thymus
- Author
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J, Onodera, T, Nagata, K, Fujihara, M, Ohuchi, N, Ishii, K, Sugamura, and Y, Itoyama
- Subjects
Adult ,Cerebral Cortex ,Male ,Medulla Oblongata ,Adolescent ,Antibodies, Monoclonal ,HLA-DR Antigens ,Thymus Gland ,Middle Aged ,Flow Cytometry ,Ligands ,Receptors, Tumor Necrosis Factor ,Antigens, CD ,Myasthenia Gravis ,Humans ,Female - Abstract
To examine the expression of OX40, an activated memory T-cell marker, and its ligand (OX40L), a set of molecules for T-cell-B-cell interaction, and other lymphocyte activation markers in the thymuses of myasthenia gravis (MG) and controls.We studied the expression of OX40, OX40L, IL-2Ralpha and HLA-DR in the thymic tissues of MG and controls using immunocytochemistry and flowcytometry.In both hyperplastic thymus of MG and control thymus, OX40+ cells were scattered mainly in the medulla with much fewer OX40L+ cells being distributed in the corticomedullary junctions. IL-2Ralpha and HLA-DR were expressed in the medulla at higher frequencies as compared with OX40 in controls as well as MG. In contrast, the numbers of OX40+ cells around the germinal centers (GC) were significantly greater than those of control thymuses, and some mononuclear cells in GC were OX40L+. A considerable number of OX40+ cells were seen in the thymic tissues adjacent to thymomas. OX40+ cells were CD4+ CD8- or CD4+ CD8+ and were mostly HLA-DR-. (The coexpression of OX40 and IL-2Ralpha on activated CD4+ T cells was previously reported.)OX40, expressed in a fraction of activated CD4+ T cells, may be upregulated in thymic tissues adjacent to GC and thymoma in MG, and OX40 may interact with OX40L in GC to enhance anti-acetylcholine receptor antibody production in MG.
- Published
- 2000
41. [Active site for fusion activity of influenza virus hemagglutinin]
- Author
-
M, Ohuchi and R, Ohuchi
- Subjects
Models, Molecular ,Binding Sites ,Hemagglutinin Glycoproteins, Influenza Virus ,Viral Fusion Proteins - Abstract
A sequence of hydrophobic amino acids at the N-terminus of HA2 subunit of hemagglutinin (HA) is thought to be the active site for fusion activity, and called "fusion peptide". At neutral pH, fusion peptides are located inside the stem of HA spike. At pH 5, the heads of HA spike are dissociated and thereby fusion peptides are exposed and relocated probably at the top of newly formed long alpha-helix trimer. Fusogenic HA2 bridges two adjacent membranes by plunging fusion peptide into the target membrane. HA molecule is metastable at neutral pH. Oligosaccharides in the stem region, which are strictly conserved among various strains, maintain HA in the metastable form required for fusion activity. Cytoplasmic tail of HA also participates in fusion process. Addition of 5 amino acids at the end of cytoplasmic tail abolishes the fusion activity without affecting other biological properties of HA.
- Published
- 1997
42. [Comparison of long-term clinical results of the three models of the Björk-Shiley valve prosthesis and the Omnicarbon valve prosthesis]
- Author
-
S, Ohta, M, Ohuchi, K, Katsumoto, Y, Hosoi, N, Kitamura, M, Tanizaki, K, Ihara, and S, Sumida
- Subjects
Bioprosthesis ,Male ,Survival Rate ,Heart Valve Prosthesis ,Heart Valve Diseases ,Humans ,Female ,Middle Aged ,Retrospective Studies - Abstract
A multi-institutional cooperative study, that was a comparison of long-term results of the replacement of the four models of the oblique disc valve prosthesis which had been implanted on aortic and mitral position alone or double from December 1976 to September 1992 in the eight national hospitals in Japan was performed. Seven hundred and thirty-four patients and 765 prostheses that consisted of 582 patients and 610 prostheses of the Björk-Shiley (BS) valve, including 326 patients of the Spherical disc (SP) valve (49 aortic, 259 mitral, and 18 double aortic-mitral), 103 patients of the Convexoconcave disc (CC) valve (45, 51, 7) and 153 patients of the Monostrut (MS) valve (101, 49, 3), and of 152 patients (71, 78, 3) and 155 prostheses of the Omnicarbon (OC) valve were compared with their mortality and morbidity in every valve position respectively according to the approval by STS-guideline. The MS valve and the OC valve showed 0% to 11.3% of operative mortality, 0.3%/py to 1.8%/py of valve related mortality, 85.5% +/- 5.6% to 98.4% +/- 1.6% of actuarial survival rate at 10 years, and 58.5% +/- 6.4% to 82.7% +/- 5.7% of actuarial free rate of all mortality and morbidity at 10 years in every valve position. Structural deteriorations occurred in two patients of the CC valve in the mitral position only, and its rate of all valve positions showed 0.04%/py. Significant differences were seen in actuarial survival rate at 10 years after aortic valve replacement, and in operative mortality rate, improved degree of NYHA class, structural deterioration rate and actuarial free rate of all mortality and morbidity after mitral valve replacement between the group of the MS and OC valve and the group of the SP and CC valve. Therefore the MS valve or the OC valve should be selected to implant rather than the SP valve or the CC valve, and the patient who had been implanted with the CC valve should be treated considering valve position, valve position, valve size, age and activity of the patient and the manufactured date of the prosthesis.
- Published
- 1995
43. [Solitary fibrous tumor (SFT) of the thymic area--a case report]
- Author
-
Y, Shoji, M, Ohuchi, and I, Yoshida
- Subjects
Male ,Mesothelioma ,Radiography ,Humans ,Middle Aged ,Mediastinal Neoplasms - Abstract
A 52-year-old man was referred to our hospital with a large anterior mediastinal tumor on chest X-ray. A preoperative CT scan revealed the large tumor in front of the ascending aorta. We failed aspiration biopsies for several times because of scant tumor cells. This tumor was totally removed with a small part of the pericardium through median sternotomy after preoperative radiation therapy consisting of a total dose of 25 Gy. There was no metastasis to regional lymph nodes nor dissemination in the anterior mediastinum. The tumor was encapsulated, 9 x 12 cm in size, 270 g in weight with necrotic region induced by preoperative radiation therapy. We made the diagnosis of solitary fibrous tumor of the thymic area by pathological examination and immunohistochemical study. SFT most frequently arises in the pleura and is less frequently observed in the pericardium and peritoneum. But SFT of the mediastinum has been rarely reported in the world and this is the second case in Japan.
- Published
- 1993
44. [Surgical treatment in the patients with ocular type myasthenia gravis associated with thymoma]
- Author
-
Y, Itoh, M, Ohuchi, I, Yoshida, Y, Shoji, and M, Ohmi
- Subjects
Adult ,Male ,Thymoma ,Myasthenia Gravis ,Blepharoptosis ,Humans ,Female ,Thymus Neoplasms ,Middle Aged ,Thymectomy - Abstract
During past 16 years, 192 patients underwent surgery for myasthenia gravis including 40 patients with pure ocular symptoms in our institute. In these 40 patients, 8 were associated with thymoma. The clinical stages of the thymomas were registered into Stage I (n = 5), Stage II (n = 1), Stage III (n = 1), Stage IV (n = 1) according to the classification of Masaoka and colleagues. All patients underwent extended thymothymectomy. The patient in stage III had been well until generalized myasthenic symptoms appeared 4 years after the surgery. Since the chest X-ray film revealed the tumor shadow on the right diaphragm, removal of the tumor was performed. Although he developed myasthenic crisis postoperatively, he is well controlled medically. Other 7 patients have been doing well. We concluded that a close postoperative follow up should be performed for the patients with ocular type myasthenia gravis associated with thymoma.
- Published
- 1993
45. Long-term follow up of ventricular endocardial pacing leads. Complications, electrical performance, and longevity of 561 right ventricular leads
- Author
-
S, Kazama, K, Nishiyama, M, Machii, K, Tanaka, T, Amano, T, Nomura, M, Ohuchi, S, Kasahara, M, Nie, and A, Ishihara
- Subjects
Pacemaker, Artificial ,Time Factors ,Incidence ,Humans ,Equipment Failure ,Equipment Design ,Electrodes, Implanted ,Endocardium ,Follow-Up Studies - Abstract
Five hundred and sixty-one endocardial pacing leads implanted in the right ventricle of 502 patients between 1971 and 1990 were followed for up to 17 years regarding their complications, stimulation threshold behavior, and overall longevity. Lead tip dislodgment occurred in 16 leads (2.9%), in 14 of which dislodgement occurred within 2 months after implantation. The incidence of dislodgement was significantly smaller in tined leads than in nontined leads. Lead conductor fracture occurred in 19 leads (3.4%), in 15 of which fracture occurred within 5 years after implantation. Two particular sites of lead fracture were identified; i.e., one within the pacemaker pocket and the other at a particular point in the subclavian vein between the clavicle and the first rib. Fixation ligature in the former site and the venopuncture point for lead insertion in the latter site are thought to be related to lead fracture. Other complications included insulator break in 3 leads (0.5%), exit block in 7 leads (1.2%), and poor sensing in 2 leads (0.4%). The cumulative survival of leads was 94.1 +/- 2.7% (mean +/- 95% confidence interval) at 5 years, 86.3 +/- 6.3% at 10 years, and 74.2 +/- 14.0% at 15 years after implantation. The minimal stimulation threshold, lead impedance and R wave amplitude were all found to be stable for up to 10 years, and there were no tendencies toward higher stimulation threshold during the observation period of this study.
- Published
- 1993
46. [Management of myasthenia gravis (MG) associated with thymoma]
- Author
-
M, Ohuchi, Y, Shoji, T, Nakame, Y, Itoh, and M, Ohmi
- Subjects
Adult ,Male ,Thymoma ,Myasthenia Gravis ,Humans ,Female ,Thymus Neoplasms ,Middle Aged ,Thymectomy ,Combined Modality Therapy ,Aged - Abstract
From June 1975 to June 1992, we experienced 203 patients with MG. Sixty patients had associated thymoma, registering stages I (n = 31), II (n = 18), III (n = 9), and IV a (n = 2), according to the classification of Masaoka and colleagues. Fifty patients had generalized MG and 10 had ocular MG. Histopathological findings indicated round-oval, polygonal cell type in 46 patients and mixture of round-oval and spindle cell type in 11 patients and invasive thymomas had a tendency to have a predominantly epithelial type with and increased epithelial element as compared with non-invasive thymomas. An extended thymectomy including thymoma was performed in all patients. Three patients in stage II, 7 patients in stage III, and 2 patients in IV a received postoperative radiation therapy. Twenty-one patients needed prolonged respiratory care for respiratory crisis. Fifty-three patients have been doing well with the alternate-day corticosteroid therapy, however, 4 patients had an excavation of myasthenic symptoms associated with recurrence of thymoma on the pleura. In conclusion, early extended thymectomy including thymoma is markedly effective therapy for MG with thymoma and a careful attention should be paid for recurrence in the patients with invasive thymoma.
- Published
- 1993
47. [Surgical treatment of double aortic arch: report of a case associated with frequent respiratory infections]
- Author
-
Y, Itoh, M, Ohuchi, A, Itoh, and K, Kano
- Subjects
Male ,Humans ,Infant ,Aorta, Thoracic ,Prognosis ,Respiratory Tract Infections - Abstract
A seven-month-old baby with double aortic arch was reported. He was admitted to our hospital with complaint of frequent respiratory infections shortly after birth. On examination, bronchofiberscopy revealed compression of the trachea and left main bronchus from behind and angiography showed complete vascular ring, namely double aortic arch with no other cardiac anomaly. Soon after the operation, stridor disappeared at rest, but mild stridor persisted on exertion. Three months later, he was re-admitted to our hospital because of pneumonia. Therefore, close observation is required for the patients with double aortic arch, even if the operation is effective.
- Published
- 1992
48. [Surgical treatment of myasthenia gravis associated with Graves's disease]
- Author
-
Y, Itoh, M, Ohuchi, I, Yoshida, and M, Ohmi
- Subjects
Adult ,Male ,Myasthenia Gravis ,Thyroidectomy ,Humans ,Female ,Middle Aged ,Thymectomy ,Graves Disease - Abstract
During past 30 years, we experienced 253 patients who underwent surgery for myasthenia gravis. Among these patients, 9 were associated with Graves' disease. No patients had thymoma. Five patients underwent thymectomy after they had become euthyroid by medical treatment, though four patients required subtotal thyroidectomy before thymectomy. One patient developed myasthenic crisis following thyroidectomy and was treated with respirator for 5 days. But thymectomy was performed without myasthenic crisis in these four patients between 25 days and 60 days after thyroidectomy. They have been doing well and no see-saw phenomenon was presented. Thymectomy is safe and effective even in the patients with Graves's disease, and we recommend to perform it after they become euthyroid by medical or surgical treatment.
- Published
- 1992
49. [Two cases of broncholithiasis removed by bronchofiberscopy]
- Author
-
M, Nonaka, T, Arai, K, Inagaki, M, Yano, H, Miyazawa, H, Sato, M, Ohuchi, N, Ohtani, T, Suzuki, and E, Toyoda
- Subjects
Adult ,Male ,Bronchoscopy ,Fiber Optic Technology ,Humans ,Bronchial Diseases ,Female ,Calculi ,Aged - Abstract
Two cases of broncholithiasis, removed bronchoscopically, are reported. Case 1 was a 38-year-old female who was admitted with hemoptysis. The chest tomogram showed calcification near the right middle lobe bronchus. Bronchoscopy revealed a broncholith in B4. Component analysis showed that more than 98% of this stone consisted of calcium carbonate. Case 2 was a 75-year-old male who was hospitalized because of continuous cough. The chest radiograph showed calcification and atelectasis in the right upper lobe. Bronchoscopically, right B3 was obstructed by a broncholith. After removal of the stone, the distal part of B3 was noted to be filled with pus. Analysis of the stone's composition revealed calcium phosphate (77%) and calcium carbonate (23%).
- Published
- 1992
50. [A case report of cavernostomy for lung aspergilloma]
- Author
-
M, Nonaka, T, Arai, K, Inagaki, T, Morita, M, Yano, H, Migazawa, H, Sato, and M, Ohuchi
- Subjects
Male ,Lung Diseases, Fungal ,Aspergillosis ,Humans ,Lung ,Aged - Abstract
A 65-year-old male patient with right upper lobe aspergilloma treated surgically due to continuation of hemoptysis was reported. Cavernostomy was indicated in this patient, since he had a low respiratory function. After cavernostomy, cavitry infection with MRSA occurred and additional operation was necessary. We should gave great care to intra-cavitary infection. Loss of lung function after the operation seemed to be minimal.
- Published
- 1991
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