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A Two-Dimensional Study of Transonic Flow Characteristics in Steam Control Valve for Power Plant
Yonezawa, Koichi,Terachi, Yoshinori,Nakajima, Toru,Tsujimoto, Yoshinobu,Tezuka, Kenichi,Mori, Michitsugu,Morita, Ryo,Inada, Fumio Korean Society for Fluid machinery 2010 International journal of fluid machinery and syste Vol.3 No.1
A steam control valve is used to control the flow from the steam generator to the steam turbine in thermal and nuclear power plants. During startup and shutdown of the plant, the steam control valve is operated under a partial flow conditions. In such conditions, the valve opening is small and the pressure deference across the valve is large. As a result, the flow downstream of the valve is composed of separated unsteady transonic jets. Such flow patterns often cause undesirable large unsteady fluid force on the valve head and downstream pipe system. In the present study, various flow patterns are investigated in order to understand the characteristics of the unsteady flow around the valve. Experiments are carried out with simplified two-dimensional valve models. Two-dimensional unsteady flow simulations are conducted in order to understand the experimental results in detail. Scale effects on the flow characteristics are also examined. Results show three types of oscillating flow pattern and three types of static flow patterns.
Yoshiko Nakano,Toshitatsu Takao,Yoshinori Morita,Shinwa Tanaka,Takashi Toyonaga,Eiji Umegaki,Yuzo Kodama 대한소화기내시경학회 2020 Clinical Endoscopy Vol.53 No.5
Background/Aims: Mucosal cutting biopsy (MCB) is useful for the histopathological diagnosis of gastric subepithelial tumors (SETs). However, there is little information on cases in which MCB did not establish a diagnosis. In the current study, we aimed to investigatethe characteristics of cases in which MCB was unsuccessful. Methods: Cases in which MCB was used to histopathologically diagnose gastric SETs at Kobe University Hospital between August 2012and October 2018 were retrospectively reviewed. Results: Forty-five cases in which MCB was used to diagnose 43 gastric SETs in 43 patients were analyzed. The median tumor sizewas 20 mm (range, 8–50 mm). Pathological examinations resulted in definitive and suspected diagnoses and no diagnosis in 29(gastrointestinal stromal tumor: n=17, leiomyoma: n=7, aberrant pancreas: n=3, others: n=2), 6, and 10 cases, respectively. Failure toexpose the tumor according to retrospective examinations of endoscopic images was significantly associated with no diagnosis. Otherpossible explanations included a less elevated tumor, biopsy of the surrounding field instead of the tumor due to the mobility, and poorendoscope maneuverability due to the tumor being close to the cardia. Conclusions: Clear exposure of gastric SETs during MCB may improve the diagnostic rate of such examinations.
Josué Aliaga Ramos,Yoshinori Morita,Takashi Toyonaga,Danilo Carvalho,Moises Salgado Pedrosa,Vitor N. Arantes 대한소화기내시경학회 2023 Clinical Endoscopy Vol.56 No.5
Background/Aims: Endoscopic submucosal dissection (ESD) is currently considered the first-line treatment for the eradication of superficialneoplasms of the esophagus in Eastern countries. However, in the West, particularly in Latin America, the experience withesophageal ESD is still limited because of the high technical complexity required for its execution. This study aimed to present the resultsof the clinical application of ESD to manage superficial esophageal neoplasms in a Latin American center in over 100 consecutivecases. Methods: This retrospective study included consecutive patients who underwent endoscopic ESD for superficial esophageal neoplasmsbetween 2009 and 2022. The following clinical outcomes were assessed: en bloc, complete, and curative resection rates, local recurrence,adverse events, and procedure-related mortality. Results: Esophageal ESD was performed mainly for squamous cell carcinoma (66.6%), high-grade intraepithelial neoplasia (17.1%),and adenocarcinoma (11.4%). En bloc and complete resection rates were 96.2% and 81.0%, respectively. The curative resection rate was64.8%. Adverse events occurred in six cases (5.7%). Endoscopic follow-up was performed for an average period of 29.7 months. Conclusions: ESD performed by trained operators is feasible, safe, and clinically effective for managing superficial neoplastic lesions ofthe esophagus in Latin America.
Ogon Izaya,Takashima Hiroyuki,Morita Tomonori,Oshigiri Tsutomu,Terashima Yoshinori,Yoshimoto Mitsunori,Fukushi Ryunosuke,Fujimoto Shutaro,Emori Makoto,Teramoto Atsushi,Takebayashi Tsuneo,Yamashita Tos 대한척추외과학회 2020 Asian Spine Journal Vol.14 No.5
Study Design: Cross-sectional study.Purpose: The purpose of this study was to elucidate the relevance among Schmorl’s node (SN), chronic low back pain (CLBP), and intervertebral disc degeneration (IVDD) with the use of magnetic resonance imaging T2 mapping.Overview of Literature: SN may be combined with CLBP and/or IVDD; however, their relationship has not been determined to date.Methods: A total of 105 subjects were included (48 men and 57 women; mean age, 63.2±2.7 years; range, 22–84 years). We analyzed five functional spinal unit levels (L1–S1) and evaluated the T2 values of the anterior annulus fibrosus (AF), nucleus pulposus, and posterior AF. We compared the low back pain (LBP) Visual Analog Scale (VAS) scores and the T2 values in each decade with or without SN.Results: There were no remarkable differences in SN prevalence rate regarding age decade or gender. SNs were more prevalent in the upper 2 levels (70.3%). LBP VAS scores with and without SN were 64.7±4.3 mm and 61.9±2.8 mm, respectively, with no significant differences between the groups (p =0.62). The T2 values of anterior AF with SN were significantly lower than those without SN in patients in their 50s, 60s, 70s, and 80s (p <0.01).Conclusions: SN presence is not itself a risk factor for CLBP; however, it indicates IVDD of the anterior AF in subjects with SN who are ≥50 years old.
Izaya Ogon,Tsuneo Takebayashi,Hiroyuki Takashima,Tomonori Morita,Tsutomu Oshigiri,Yoshinori Terashima,Mitsunori Yoshimoto,Toshihiko Yamashita 대한척추외과학회 2019 Asian Spine Journal Vol.13 No.4
Study Design: Cross-sectional study. Purpose: To determine the association between fatty degeneration of the multifidus muscle (Mm) and intervertebral disc degeneration (IVDD) using quantitative magnetic resonance imaging (MRI). Overview of Literature: Few studies have reported on quantitative MRI analysis of the relation between the Mm and IVDD. Methods: The subjects with chronic low back pain comprised 45 patients (19 males, 26 females; mean age, 63.8±2.0 years; range, 41–79 years). We analyzed the intramyocellular lipids (IMCL) and extramyocellular lipids (EMCL) of the Mm using magnetic resonance spectroscopy. The T2 values of the anterior annulus fibrosus (AF), nucleus pulposus (NP), and posterior AF were evaluated using MRI T2 mapping. We compared the possible correlations of IMCL and EMCL of the Mm with the T2 values of anterior AF, NP, and posterior AF. Results: There was a significant negative correlation between IMCL and T2 values of the anterior AF (r=−0.65, p<0.01). There were no significant correlations between the IMCL and T2 values of NP (r=−0.16, p=0.30) and posterior AF (r=0.07, p=0.62). There were no significant correlations between the EMCL and T2 values of the anterior AF (r=−0.11, p=0.46), NP (r=0.15, p=0.32), and posterior AF (r=0.07, p=0.66). After adjustment for age and sex using multiple linear regression analysis, there was a significant negative correlation between the IMCL and T2 values of anterior AF (standardized partial regression coefficient=−0.65, p<0.01). Conclusions: The results indicated that IMCL of the Mm might be accompanied with anterior AF degeneration. Therapeutic exercises using IMCL of the Mm as evaluation index might have the potential to identify novel targets for the treatment and prevention of IVDD.
Izaya Ogon,Tsuneo Takebayashi,Hiroyuki Takashima,Tomonori Morita,Noriyuki Iesato,Katsumasa Tanimoto,Yoshinori Terashima,Mitsunori Yoshimoto,Toshihiko Yamashita 대한척추외과학회 2019 Asian Spine Journal Vol.13 No.3
Study Design: Cross sectional study. Purpose: The study aimed to analyze mechanisms underlying chronic low back pain (CLBP) using magnetic resonance imaging (MRI) T2 mapping of the intervertebral disc (IVD). Overview of Literature: MRI T2 mapping utilizes the T2 values for quantifying moisture content and collagen sequence breakdown. We previously used MRI T2 mapping for quantifying the extent of IVD degeneration (IVDD) and showed a correlation between the degeneration of the posterior annulus fibrosus (AF) and CLBP. Methods: We enrolled 40 patients with CLBP (17 males, 23 females; mean age, 50.8±1.6 years; range, 22–60 years). IVDs were categorized as the anterior AF, nucleus pulposus (NP), and posterior AF, and T2 value for each disc was measured. T2 values, assessed using the Japanese neuropathic pain (NeP) screening questionnaire, of the NeP and nociceptive pain (NocP) groups were compared. Results: T2 values of the NocP and NeP groups were 64.7±5.6 ms and 58.1±2.3 ms for the anterior AF; 67.0±4.6 ms and 59.6±2.1 ms for NP; and 70.7±4.6 ms and 51.0±1.2 ms for the posterior AF, respectively. T2 values for IVDD were significantly lower in the NeP group than those in the NocP group (p<0.01). Conclusions: The results indicate a correlation between the degeneration of posterior AF and NeP. MRI T2 mapping may be beneficial for detecting NeP caused by IVDD and can help formulate targeted analgesic therapies.
Ogon Izaya,Hiroyuki Takashima,Tomonori Morita,Tsutomu Oshigiri,Yoshinori Terashima,Mitsunori Yoshimoto,Makoto Emori,Atsushi Teramoto,Tsuneo Takebayashi,Toshihiko Yamashita 대한척추외과학회 2020 Asian Spine Journal Vol.14 No.4
Study Design: Cross-sectional observational study.Purpose: This study aimed to analyze any potential associations of extramyocellular lipid (EMCL) and intramyocellular lipid (IMCL) contents with (1) the intensity of low back pain (LBP); (2) age, cross-sectional area (CSA), and fatty infiltration (FI) of the psoas major; and (3) spinopelvic parameters.Overview of Literature: The psoas major has clinically relevant function; however, the association of this muscle with chronic LBP is controversial. Magnetic resonance spectroscopy enables a detailed analysis of the composition of muscular fat tissues such as its EMCL and IMCL contents.Methods: The study population comprised 40 patients (19 males, 21 females; mean age, 61.7±2.4 years). Possible correlations of LBP Visual Analog Scale (VAS) scores, age, CSA, FI, and spinopelvic parameters with EMCL and IMCL contents of the psoas major were assessed.Results: No association was identified between the EMCL and IMCL contents and LBP VAS scores (<i>r</i>=0.05, <i>p</i>=0.79 and <i>r</i>=0.06, <i>p</i>=0.75, respectively). The EMCL content correlated with age (<i>r</i>=0.47, <i>p</i><0.01), body mass index (BMI) (<i>r</i>=0.44, <i>p</i><0.01), CSA (<i>r</i>=−0.59, <i>p</i>< 0.01), and FI (<i>r</i>=0.49, <i>p</i><0.01). EMCL content showed a significant negative correlation with sacral slope (SS) (<i>r</i>=−0.43, <i>p</i><0.05) and positive correlation with pelvic tilt (PT) (<i>r</i>=0.56, <i>p</i><0.01).Conclusions: EMCL content correlated with age, BMI, CSA, and FI of the psoas major, while IMCL content had no correlation. This study found correlations between SS and PT and EMCL content of the psoas major, but no correlations were found between spinopelvic parameters and IMCL content of the psoas major.
PRE-ERUPTION OSCILLATIONS IN THIN AND LONG FEATURES IN A QUIESCENT FILAMENT
Joshi, Anand D.,Hanaoka, Yoichiro,Suematsu, Yoshinori,Morita, Satoshi,Yurchyshyn, Vasyl,Cho, Kyung-Suk American Astronomical Society 2016 The Astrophysical journal Vol.833 No.2
<P>We investigate the eruption of a quiescent filament located close to an active region. Large-scale activation was observed in only half of the filament in the form of pre-eruption oscillations. Consequently only this half erupted nearly 30 hr after the oscillations commenced. Time-slice diagrams of 171 angstrom images from the Atmospheric Imaging Assembly were used to study the oscillations. These were observed in several thin and long features connecting the filament spine to the chromosphere below. This study traces the origin of such features and proposes their possible interpretation. Small-scale magnetic flux cancellation accompanied by a brightening was observed at the footpoint of the features shortly before their appearance, in images recorded by the Helioseismic and Magnetic Imager. A slow rise of the filament was detected in addition to the oscillations, indicating a gradual loss of equilibrium. Our analysis indicates that a change in magnetic field connectivity between two neighbouring active regions and the quiescent filament resulted in a weakening of the overlying arcade of the filament, leading to its eruption. It is also suggested that the oscillating features are filament barbs, and the oscillations are a manifestation during the pre-eruption phase of the filaments.</P>