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Choked Surge in a Cavitating Turbopump Inducer
Watanabe, Toshifumi,Kang, Dong-Hyuk,Cervone, Angelo,Kawata, Yutaka,Tsujimoto, Yoshinobu Korean Society for Fluid machinery 2008 International journal of fluid machinery and syste Vol.1 No.1
During an experimental investigation on a 3-bladed and a 4-bladed axial inducer, a severe surge instability was observed in a range of cavitation number where the blade passage is choked and the inducer head is decreased from noncavitating value. The surge was stronger for the 4-bladed inducer as compared with a 3-bladed inducer with the same inlet and outlet blade angles. For the 4-bladed inducer, the head decreases suddenly as the cavitation number is decreased. The surge was observed after the sudden drop of head. This head drop was found to be associated with a rapid extension of tip cavity into the blade passage. The cause of surge is attributed to the decrease of the negative slope of the head-flow rate performance curve due to choke. Assuming that the difference between the 3 and 4-bladed inducers is caused by the difference of the blockage effects of the blade, a test was carried out by thickening the blades of the 3-bladed inducer. However, opposite to the expectations, the head drop became smoother and the instability disappeared on the thickened blade inducer. Examination of the pressure distribution on both inducers could not explain the difference. It was pointed out that two-dimensional cavitating flow analyses predict smaller breakdown cavitation number at higher flow rates, if the incidence angle is smaller than half of the blade angle. This causes the positive slope of the performance curve and suggests that the choked surge as observed in the present study might occur in more general cases.
Rotating Choke and Choked Surge in an Axial Pump Impeller
Watanabe, Toshifumi,Sato, Hideyoshi,Henmi, Yasuhiko,Horiguchi, Hironori,Kawata, Yutaka,Tsujimoto, Yoshinobu Korean Society for Fluid machinery 2009 International journal of fluid machinery and syste Vol.2 No.3
Unlike usual turbopump inducers, the axial flow pump tested operates very stably at design flow rate without rotating cavitation nor cavitation surge. Flow visualization suggests that this is because the tip cavity smoothly extends into the flow passage without the interaction with the leading edge of the next blade. However, at low flow rate and low cavitation number, choked surge and rotating choke were observed. Their correlation with the performance curve under cavitation is discussed and their instantaneous flow fields are shown.
Three-Dimensional Analysis of the Ideal Entry Point for Sacral Alar Iliac Screws
Watanabe Noriyuki,Takigawa Tomoyuki,Uotani Koji,Oda Yoshiaki,Misawa Haruo,Tanaka Masato,Ozaki Toshifumi 대한척추외과학회 2022 Asian Spine Journal Vol.16 No.6
Study Design: This is a virtual three-dimensional (3D) imaging study examining computed tomography (CT) data to investigate instrumentation placement.Purpose: In this study, we aim to clarify the ideal entry point and trajectory of the sacral alar iliac (SAI) screw in relationship to the dorsal foramen at S1 and the respective nerve root.Overview of Literature: To the best of our knowledge, there is yet no detailed 3D imaging study on the ideal entry point of the SAI screw. Despite the evidence suggesting that the dorsal foramen at S1 is a landmark on the sacrum, the S1 nerve root disruption is a general concern during the insertion of SAI screws. No other study has been published examining the nerve root location at the S1and SAI screw insertions.Methods: Preoperative CT data from 26 patients pertaining to adult spinal deformities were investigated in this study. We applied a 3D image processing method for a detailed investigation. Virtual cylinders were used to mimic SAI screws. These were placed to penetrate the sacral iliac joint without violating the other cortex. We then assessed the trajectory of the longest SAI screw and the ideal entry point of SAI using a color mapping method on the surface of the sacrum. We measured the location of the nerve root at S1 in relation to the foramen at S1 and the sacral surface.Results: As per the results of our color mapping, it was determined that areas that received high scores are located medially and caudally to the dorsal foramen of S1. The mean angle between a horizontal line and a line connecting the medial edge of the foramen and nerve root at S1 was 93.5°. The mean distances from the dorsal medial edge of the foramen and sacral surface to S1 nerve root were 21.8 mm and 13.9 mm, respectively.Conclusions: The ideal entry point of the SAI screw is located medially and caudally to the S1 dorsal foramen based on 3D digital mapping. It is also shown that this entry point spares the S1 nerve root from possible iatrogenic injuries.
Toshifumi Hibi,Satoshi Motoya,Tadakazu Hisamatsu,Fumihito Hirai,Kenji Watanabe,Katsuyoshi Matsuoka,Masayuki Saruta,Taku Kobayashi,Brian G Feagan,Chantal Tasset,Robin Besuyen,Chohee Yun,Gerald Crans,Ji 대한장연구학회 2023 Intestinal Research Vol.21 No.1
Background/Aims: The safety and efficacy of filgotinib, a once-daily oral Janus kinase 1 preferential inhibitor, were evaluated in Japanese patients with ulcerative colitis (UC) in the phase 2b/3 SELECTION trial. Methods: SELECTION (NCT02914522) was a randomized, placebo-controlled trial comprising 2 induction studies and a maintenance study. Adults with moderately to severely active UC were randomized in induction study A (biologic-naïve) or B (biologic-experienced) to receive filgotinib 200 mg, 100 mg, or placebo once daily for 11 weeks. Patients in clinical remission or Mayo Clinic score response at week 10 entered the 47-week maintenance study. Efficacy and safety outcomes were assessed in Japanese patients enrolled in Japan. Results: Overall, 37 and 72 Japanese patients were enrolled in Japan in induction studies A and B, respectively, and 54 entered the maintenance study. Numerically higher proportions of filgotinib 200 mg-treated than placebo-treated patients achieved clinical remission in induction study A (4/15 [26.7%] vs. 0/6 [0%]) and the maintenance study (5/20 [25.0%] vs. 0/9 [0%]), but not induction study B (1/29 [3.4%] vs. 1/14 [7.1%]). Both doses were well tolerated, and no new safety signals were noted. Herpes zoster was reported in 1 filgotinib 200 mg-treated patient in each of induction study A (2.3%, 1/44) and the maintenance study (5.0%, 1/20). Conclusions: These data, alongside those of the overall SELECTION population, suggest the potential of filgotinib 200 mg as a viable treatment option for Japanese patients with UC. Owing to small patient numbers, data should be interpreted cautiously.
( Toshifumi Hibi ),( Makoto Naganuma ),( Eisei Oda ),( Yoji Yamada ),( Yoshitomo Chujoh ),( Ryoichi Yoshihara ),( Mamoru Watanabe ) 대한장연구학회 2020 Intestinal Research Vol.18 No.1
Background/Aims: Mucosal healing (MH) of distal lesions in ulcerative colitis (UC) has recently been confirmed with budesonide 2-mg foam (BF) treatment in 2 clinical trials; however, few studies have investigated the predictive factors for complete MH. Methods: We conducted a post hoc analysis using pooled data from phase II and III clinical trials evaluating the efficacy and safety of BF for UC. Additionally, we analyzed the relationships between complete MH and baseline factors and clinical symptoms from baseline to week 6. Results: Among the 291 Japanese patients from the 2 pooled clinical studies, 119 patients in the BF twice a day group and 117 in the placebo group were included in the full analysis set. The proportion of patients with a rectal bleeding (RB) subscore of 0 was significantly higher in the BF group than in the placebo group after a 5-day treatment (P<0.05). After a 2-day treatment, significantly more patients in the BF group had a stool frequency (SF) subscore of 0 than patients in the placebo group (P<0.05). Multivariate analysis showed that complete MH at week 6 was influenced by baseline SF subscore and 5-aminosalicylic acid (5-ASA) enema or suppository use (P=0.0086 and P=0.0015, respectively). The relationship between complete MH at week 6 and RB subscore after week 2 was also confirmed. Conclusions: Normal SF at baseline, history of 5-ASA topical product use, and elimination of RB after week 2 are suggested predictors of complete MH at week 6 with twice-daily BF treatment. (Intest Res 2020;18:56-68)
( Takashi Hoshino ),( Toshifumi Watanabe ),( Yusuke Nakagawa ),( Hiroki Katagiri ),( Nobutake Ozeki ),( Toshiyuki Ohara ),( Mikio Shioda ),( Yuji Kono ),( Ichiro Sekiya ),( Hideyuki Koga ) 대한슬관절학회 2021 대한슬관절학회지 Vol.33 No.-
Purpose: This study assessed the clinical outcomes of periprosthetic joint infection patients who underwent twostage revision total knee arthroplasty with antibiotic-loaded cement spacers fabricated using a handmade silicone mold. Materials and methods: This study included seven patients (average age 77 years, average follow-up time 54 months) who underwent surgery at our hospital between 2009 and 2013. Clinical outcomes including knee scores, function scores, knee range of motion, and walking ability at the final observation, period from the primary total knee arthroplasty to implant removal, period from implant removal to revision total knee arthroplasty, and followup period after revision total knee arthroplasty were investigated. Results: At the final follow-up, the average knee range of motion was 99°, with no significant differences at each stage; average knee and function scores were 84 and 77, respectively. With cement spacers, five patients were able to walk with a t-cane. No recurrence of infection was observed. Conclusions: The clinical outcomes of the current case series demonstrated good knee function with preserved walking ability, without any recurrence of periprosthetic joint infection. This study suggests that using a handmade silicone mold could be an effective option for periprosthetic joint infection after a total knee arthroplasty.
Inducer Design to Avoid Cavitation Instabilities
Kang, Dong-Hyuk,Watanabe, Toshifumi,Yonezawa, Koichi,Horiguchi, Hironori,Kawata, Yutaka,Tsujimoto, Yoshinobu Korean Society for Fluid machinery 2009 International journal of fluid machinery and syste Vol.2 No.4
Three inducers were designed to avoid cavitation instabilities. This was accomplished by avoiding the interaction of tip cavity with the leading edge of the next blade. The first one was designed with extremely larger leading edge sweep, the second and third ones were designed with smaller incidence angle by reducing the inlet blade angle or increasing the design flow rate, respectively. The inducer with larger design flow rate has larger outlet blade angle to obtain sufficient pressure rise. The inducer with larger sweep could suppress the cavitation instabilities in higher flow rates more than 95% of design flow coefficient, owing to weaker tip leakage vortex cavity with stronger disturbance by backflow vortices. The inducer with larger outlet blade angle could avoid the cavitation instabilities at higher flow rates, owing to the extension of the tip cavity along the suction surface of the blade. The inducer with smaller inlet blade angle could avoid the cavitation instabilities at higher flow rates, owing to the occurrence of the cavity first in the blade passage and its extension upstream. The cavity shape and suction performance were reasonably simulated by three dimensional CFD computations under the steady cavitating condition, except for the backflow vortex cavity. The difference in the growth of cavity for each inducer is explained from the difference of the pressure distribution on the suction side of the blades.
( Satoshi Motoya ),( Mamoru Watanabe ),( Hyo Jong Kim ),( Young Ho Kim ),( Dong Soo Han ),( Hirotoshi Yuasa ),( Junichi Tabira ),( Naoki Isogawa ),( Shoko Arai ),( Isao Kawaguchi ),( Toshifumi Hibi ) 대한장연구학회 2018 Intestinal Research Vol.16 No.2
Background/Aims: Tofacitinib is an oral, small-molecule Janus kinase inhibitor being investigated for ulcerative colitis (UC). In OCTAVE Induction 1 and 2, patients with moderately to severely active UC received placebo or tofacitinib 10 mg twice daily (BID) for 8 weeks. Clinical responders in OCTAVE Induction were re-randomized to 52 weeks’ therapy with placebo, tofacitinib 5 mg BID, or tofacitinib 10 mg BID. Methods: We conducted post-hoc efficacy and safety analyses of East Asian patients in OCTAVE Induction 1 and 2 and OCTAVE Sustain. Results: A total of 121 East Asian (Japan, Korea, and Taiwan) patients were randomized in OCTAVE Induction 1 and 2 (placebo, n=26; tofacitinib 10 mg BID, n=95), and 63 in OCTAVE Sustain (placebo, n=20; tofacitinib 5 mg BID, n=22; tofacitinib 10 mg BID, n=21). At week 8 of OCTAVE Induction 1 and 2, 18.9% of patients (18/95) achieved remission with tofacitinib 10 mg BID versus 3.8% (1/26) with placebo. In OCTAVE Sustain, the week 52 remission rates were 45.5% (10/22), 47.6% (10/21), and 15.0% (3/20) with 5 mg BID, 10 mg BID, and placebo, respectively. Adverse event rates were similar between groups in OCTAVE Induction and numerically higher with tofacitinib in OCTAVE Sustain. Serious adverse event rates were similar across groups in all studies. Infections were numerically more frequent with tofacitinib than placebo. Increases in serum lipid levels were observed with tofacitinib. Conclusions: In East Asian patients with UC, tofacitinib demonstrated numerically greater efficacy versus placebo as induction and maintenance therapy, with a safety profile consistent with the global study population. ClinicalTrials.gov: NCT01465763; NCT01458951; NCT01458574. (Intest Res 2018;16:233-245)
( Tadakazu Hisamatsu ),( Yasuo Suzuki ),( Mariko Kobayashi ),( Takashi Hagiwara ),( Takeshi Kawaberi ),( Haruhiko Ogata ),( Toshiyuki Matsui ),( Mamoru Watanabe ),( Toshifumi Hibi ) 대한장연구학회 2021 Intestinal Research Vol.19 No.4
Background/Aims: Crohn’s disease is a chronic disorder; therefore, it is essential to investigate long-term safety and efficacy of treatments. This study assessed the safety and effectiveness of adalimumab for up to 3 years in Japanese patients with Crohn’s disease in real-world settings. Methods: This was a multicenter, single-cohort, observational study of patients with Crohn’s disease. Safety assessments included incidence of adverse drug reactions. Effectiveness assessments included clinical remis-sion, mucosal healing, and Work Productivity and Activity Impairment (WPAI). Results: The safety and effectiveness analysis populations comprised 389 and 310 patients, respectively. Mean (standard deviation) exposure to adalimumab in the safety analysis population was 793.4 (402.8) days, with a 58.1% retention rate. A total of 105 patients (27.0%) and 43 patients (11.1%) experienced adverse drug reactions and serious adverse drug reactions, respectively, with no patient reporting tuberculosis or hepatitis B. Infections and serious infections were reported in 37 patients (9.5%) and 17 patients (4.4%), respectively. Malig-nancy was reported as an adverse drug reaction in 2 patients (0.5%). Remission rate increased from 37.8% (98/259) at baseline to 73.9% (167/226) at week 4 and remained >70% over 3 years. Proportion of patients without mucosal ulcerations increased from 2.7% (2/73) at baseline to 42.3% (11/26) between years >2 to ≤3. WPAI improvement started at 4 weeks, with the overall work impairment score improving from 42.7 (n=102) at baseline to 26.9 (n=84) at 4 weeks. Conclusions: Results from this study confirm the long-term safety and effectiveness of adalimumab treatment in Japanese patients with Crohn’s disease in the real-world setting. (Intest Res 2021;19:408-418)