Unstable Vibrations of a Rotating Shaft Driven through a Universal Joint

Masayoshi Kato,Hiroshi Ota,Jeong Ryul Kim,Riichi Kato 대한기계학회 1997 Asia-Pacific Vibration Conference Vol.1 No.1

Unstable Vibrations of a Rotating shaft Driven through a Universal Joint

Masayoshi Kato,Hiroshi Ota,Jeong-Ryul Kim,Riichi Kato 한국소음진동공학회 1997 한국소음진동공학회 국제학술대회논문집 Vol.1997 No.1

Synthesis and Luminescence Properties of a Cyan-blue Thiosilicate-based Phosphor SrSi2S5:Eu2+

Masayoshi Nakamura,Hideki Kato,Yuji Takatsuka,Valery Petrykin,Satoko Tezuka,Masato Kakihana 한국정보디스플레이학회 2010 Journal of information display Vol.11 No.4

A series of Sr-Si-S compounds was synthesized using an advanced chemical method in which the use of one solution-based process uniformly dispersed the Eu2+ activators in the host crystals, to find new compositions that would suit phosphor applications. Particular focus was given to the Si-rich region. This led to the synthesis of a single-phase compound that showed an unknown X-ray diffraction pattern. This compound had a composition close to that of SrSi2S5. When this compound is activated with Eu2+ (SrSi2S5:Eu2+), it shows a cyan-blue emission with a main luminescence peak at 495 nm. This emission is excited by wavelengths of 250-440 nm and has a maximum excitation at 350 nm.

Multivariate prognostic analysis of adenocarcinoma of the uterine cervix treated with radical hysterectomy and systematic lymphadenectomy

Tatsuya Kato,Hidemichi Watari,Mahito Takeda,Masayoshi Hosaka,Takashi Mitamura,Noriko Kobayashi,Satoko Sudo,Masanori Kaneuchi,Masataka Kudo,Noriaki Sakuragi 대한부인종양학회 2013 Journal of Gynecologic Oncology Vol.24 No.3

Objective: The aim of this study was to investigate the prognostic factors and treatment outcome of patients with adenocarcinoma of the uterine cervix who underwent radical hysterectomy with systematic lymphadenectomy. Methods: A total of 130 patients with stage IB to IIB cervical adenocarcinoma treated with hysterectomy and systematic lymphadenectomy from 1982 to 2005 were retrospectively analyzed. Clinicopathological data including age, stage, tumor size, the number of positive node sites, lymphovascular space invasion, parametrial invasion, deep stromal invasion (>2/3 thickness), corpus invasion, vaginal infiltration, and ovarian metastasis, adjuvant therapy, and survival were collected and Cox regression analysis was used to determine independent prognostic factors. Results: An estimated five-year survival rate of stage IB1 was 96.6%, 75.0% in stage IB2, 100% in stage IIA, and 52.8% in stage IIB. Prognosis of patients with one positive-node site is similar to that of those with negative-node. Prognosis of patients with multiple positive-node sites was significantly poorer than that of negative and one positive-node site. Multivariate analysis revealed that lymph node metastasis, lymphovascular space invasion, and parametrial invasion were independent prognostic factors for cervical adenocarcinoma. Survival of patients with cervical adenocarcinoma was stratified into three groups by the combination of three independent prognostic factors. Conclusion: Lymph node metastasis, lymphovascular space invasion, and parametrial invasion were shown to be independent prognostic factors for cervical adenocarcinoma treated with hysterectomy and systematic lymphadenectomy.

Surgical Outcomes of Multilevel Posterior Lumbar Interbody Fusion versus Lateral Lumbar Interbody Fusion for the Correction of Adult Spinal Deformity: A Comparative Clinical Study

Iwamae Masayoshi,Matsumura Akira,Namikawa Takashi,Kato Minori,Hori Yusuke,Yabu Akito,Sawada Yuta,Noriaki Hidaka,Nakamura Hiroaki 대한척추외과학회 2020 Asian Spine Journal Vol.14 No.4

Study Design: A retrospective case control study.Purpose: The purpose of this study was to compare the surgical outcomes of multilevel lateral lumbar interbody fusion (LIF) and multilevel posterior lumbar interbody fusion (PLIF) in the surgical treatment of adult spinal deformity (ASD) and to evaluate the sagittal plane correction by combining LIF with posterior-column osteotomy (PCO).Overview of Literature: The surgical outcomes between multilevel LIF and multilevel PLIF in ASD patients remain unclear.Methods: We retrospectively reviewed 31 ASD patients who underwent multilevel LIF combined with PCO (LIF group, n=14) or multilevel PLIF (PLIF group, n=17) and with a minimum 2-year follow-up. In the comparison between LIF and PLIF groups, their mean age at surgery was 69.4 vs. 61.8 years while the mean follow-up period was 29.2 vs. 59.3 months. We evaluated the transition of pelvic incidence–lumbar lordosis (PI–LL) and disc angle (DA) in the LIF group, in fulcrum backward bending (FBB), after LIF and after posterior spinal fusion (PSF) with PCO. The spinopelvic radiographic parameters were compared between LIF and PLIF groups.Results: Compared with the PLIF group, the LIF group had less blood loss and comparable surgical outcomes with respect to radiographic data, health-related quality of life scores and surgical time. In the LIF group, the mean DA and PI–LL were unchanged after LIF (DA, 5.8°; PI–LL, 15°) compared with the values using FBB (DA, 4.3°; PI–LL, 15°) and improved significantly after PSF with PCO (DA, 8.1°; PI–LL, 0°).Conclusions: In the surgical treatment of ASD, multilevel LIF is less invasive than multilevel PLIF and combination of LIF and PCO would be necessary for optimal sagittal correction in patients with rigid deformity.

Effect of PTFE contents in the Gas Diffusion Layers of Polymer Electrolyte-based Unitized Reversible Fuel Cells

Hwang, Chul-Min,Ishida, Masayoshi,Ito, Hiroshi,Maeda, Tetsuhiko,Nakano, Akihiro,Kato, Atsushi,Yoshida, Tetsuya The Korean Institute of Electrical Engineers 2012 The Journal of International Council on Electrical Vol.2 No.2

Polymer electrolyte-based unitized reversible fuel cells (URFCs) combine the functionality of a fuel cell and an electrolyzer in a single device. In this study, the influence of hydrophobic agent in the gas diffusion layer (GDL) of URFC was investigated. The titanium (Ti)-felt GDL which treated with different percent of PTFE emulsion was intensively tested with various humidification temperature conditions in the single cell of URFC. I-V performance curves and divided three overpotentials were compared and analyzed in the fuel cell mode. The electrolyzer performances were also evaluated with the I-V curves. Experimental results showed that the GDLs with high PTFE contents have better performance in the dry conditions. On the other hand, the increased PTFE contents accelerate flooding problem in the wet condition and it is related with rising concentration overpotential. The electrolyzer performances are almost same with different PTFE contents of GDL.

Multivariate survival analysis of the patients with recurrent endometrial cancer

Tetsuji Odagiri,Hidemichi Watari,Masayoshi Hosaka,Takashi Mitamura,Yousuke Konno,Tatsuya Kato,Noriko Kobayashi,Satoko Sudo,Mahito Takeda,Masanori Kaneuchi,Noriaki Sakuragi 대한부인종양학회 2011 Journal of Gynecologic Oncology Vol.22 No.1

Objective: Few studies on the prognosticators of the patients with recurrent endometrial cancer after relapse have been reported in the literature. The aim of this study was to determine the prognosticators after relapse in patients with recurrent endometrial cancer who underwent primary complete cytoreductive surgery and adjuvant chemotherapy. Methods: Thirty-five patients with recurrent endometrial cancer were included in this retrospective analysis. The prognostic significance of several clinicopathological factors including histologic type, risk for recurrence, time to relapse after primary surgery, number of relapse sites, site of relapse, treatment modality, and complete resection of recurrent tumors were evaluated. Survival analyses were performed by Kaplan-Meier curves and the log-rank test. Independent prognostic factors were determined by multivariate Cox regression analysis. Results: Among the clinicopathological factors analyzed, histologic type (p=0.04), time to relapse after primary surgery (p=0.03), and the number of relapse sites (p=0.03) were significantly related to survival after relapse. Multivariate analysis revealed that time to relapse after primary surgery (hazard ratio, 6.8; p=0.004) and the number of relapse sites (hazard ratio, 11.1; p=0.002) were independent prognostic factors for survival after relapse. Survival after relapse could be stratified into three groups by the combination of two independent prognostic factors. Conclusion: We conclude that time to relapse after primary surgery, and the number of relapse sites were independent prognostic factors for survival after relapse in patients with recurrent endometrial cancer. Objective: Few studies on the prognosticators of the patients with recurrent endometrial cancer after relapse have been reported in the literature. The aim of this study was to determine the prognosticators after relapse in patients with recurrent endometrial cancer who underwent primary complete cytoreductive surgery and adjuvant chemotherapy. Methods: Thirty-five patients with recurrent endometrial cancer were included in this retrospective analysis. The prognostic significance of several clinicopathological factors including histologic type, risk for recurrence, time to relapse after primary surgery, number of relapse sites, site of relapse, treatment modality, and complete resection of recurrent tumors were evaluated. Survival analyses were performed by Kaplan-Meier curves and the log-rank test. Independent prognostic factors were determined by multivariate Cox regression analysis. Results: Among the clinicopathological factors analyzed, histologic type (p=0.04), time to relapse after primary surgery (p=0.03), and the number of relapse sites (p=0.03) were significantly related to survival after relapse. Multivariate analysis revealed that time to relapse after primary surgery (hazard ratio, 6.8; p=0.004) and the number of relapse sites (hazard ratio, 11.1; p=0.002) were independent prognostic factors for survival after relapse. Survival after relapse could be stratified into three groups by the combination of two independent prognostic factors. Conclusion: We conclude that time to relapse after primary surgery, and the number of relapse sites were independent prognostic factors for survival after relapse in patients with recurrent endometrial cancer.

Autogenic Rib Graft for Atlantoaxial and Occipitocervical Fixation in Pediatric Patients

Akira Matsumura,Takashi Namikawa,Minori Kato,Yusuke Hori,Masayoshi Iwamae,Noriaki Hidaka,Sadahiko Konishi,Hiroaki Nakamura 대한척추외과학회 2019 Asian Spine Journal Vol.13 No.5

Study Design: Retrospective case series. Purpose: To evaluate surgical outcomes and effectiveness of an autogenic rib graft for upper cervical fixation in pediatric patients. Overview of Literature: Autogenic bone grafts have long been considered the ‘gold standard’ bone source for posterior cervical fusion in pediatric patients. However, there are some unsolved problems associated with donor-site morbidity and amount of bone grafting. Methods: We studied five consecutive pediatric patients who underwent atlantoaxial fixation or occipitocervical fixation (OCF) using an autogenic rib graft with at least 2 years of follow-up (mean age, 9.8 years; mean follow-up period, 73.0 months). Two patients underwent OCF without screw-rod constructs and three patients with screw-rod constructs. Autogenic rib grafts were used in all patients. We evaluated the surgical outcomes including radiographic parameter, bony union, and perioperative complications. Results: The atlantoaxial interval (ADI) was corrected from 11.6 to 6.0 mm, and the C1–2 angle was corrected −14.8° to 7.8°. The C2–7 angle was reduced from 31° to 9° spontaneously. Two patients with OCF required revision surgery due to loss of correction. Patients did not experience any complication associated with the donor sites (rib bone grafts). Six months postoperation X-rays clearly showed regeneration of the rib at the donor sites. Bony fusion was achieved in all patients; however, bony fusion occurred more slowly in patients without screw-rod constructs compared with patients with screw-rod constructs. Bone regeneration of the rib was observed in all patients with no complications at the donor site. Conclusions: Autogenic rib grafts have advantages of potential bone regeneration, high fusion rate, and low donor-site morbidity. In addition, a screw-rod construct provides better bony fusion in pediatric patients with OCF and atlantoaxial fixation.

Lymphadenectomy can be omitted for low-risk endometrial cancer based on preoperative assessments

Takashi Mitamura,Hidemichi Watari,Yukiharu Todo,Tatsuya Kato,Yosuke Konno,Masayoshi Hosaka,Noriaki Sakuragi 대한부인종양학회 2014 Journal of Gynecologic Oncology Vol.25 No.4

Objective: According to the International Federation of Gynecology and Obstetrics staging, some surgeons perform lymphadenectomy in all patients with early stage endometrial cancer to enable the accurate staging. However, there are some risks to lymphadenectomy such as lower limb lymphedema. The aim of this study was to investigate whether preoperative assessment is useful to select the patients in whom lymphadenectomy can be safely omitted. Methods: We evaluated the risk of lymph node metastasis (LNM) using LNM score (histological grade, tumor volume measured in magnetic resonance imaging [MRI], and serum CA-125), myometrial invasion and extrautrerine spread assessed by MRI. Fifty-six patients of which LNM score was 0 and myometrial invasion was less than 50% were consecutively enrolled in the study in which a lymphadenectomy was initially intended not to perform. We analyzed several histological findings and investigated the recurrence rate and overall survival. Results: Fifty-one patients underwent surgery without lymphadenectomy. Five (8.9%) who had obvious myometrial invasion intraoperatively underwent systematic lymphadenectomy. One (1.8%) with endometrial cancer which was considered to arise from adenomyosis had para-aortic LNM. Negative predictive value of deep myometrial invasion was 96.4% (54/56). During the mean follow-up period of 55 months, one patient with deep myometrial invasion who refused an adjuvant therapy had tumor recurrence. The overall survival rate was 100% during the study period. Conclusion: This preoperative assessment is useful to select the early stage endometrial cancer patients without risk of LNM and to safely omit lymphadenectomy.

Short-Term Risk Factors for Distal Junctional Kyphosis after Spinal Reconstruction Surgery in Patients with Osteoporotic Vertebrae

Sawada Yuta,Takahashi Shinji,Terai Hidetomi,Kato Minori,Toyoda Hiromitsu,Suzuki Akinobu,Tamai Koji,Yabu Akito,Iwamae Masayoshi,Nakamura Hiroaki 대한척추외과학회 2024 Asian Spine Journal Vol.18 No.1

Study Design: Level 3 retrospective cohort case-control study.Purpose: This study aimed to investigate the risk factors for distal junctional kyphosis (DJK) caused by osteoporotic vertebral fractures following spinal reconstruction surgery, with a focus on the sagittal stable vertebra.Overview of Literature: Despite the rarity of reports on DJK in this setting, DJK was reported to reduce when the lower instrumented vertebra (LIV) was extended to the sagittal stable vertebra in the posterior corrective fixation for Scheuermann’s disease.Methods: This study included 46 patients who underwent spinal reconstruction surgery for thoracolumbar osteoporotic vertebral fractures and kyphosis and were followed up for 1 year postoperatively. DJK was defined as an advanced kyphosis angle >10° between the LIV and one lower vertebra. The patients were divided into groups with and without DJK. The risk factors of the two groups, such as patient background, surgery-related factors, radiographic parameters, and clinical outcomes, were analyzed.Results: The DJK and non-DJK groups included 14 and 32 patients, respectively, without significant differences in patient background. Those with instability in the distal adjacent LIV disc had a significantly higher risk of DJK occurrence (28.6% vs. 3.2%, <i>p</i>=0.027). DJK occurrence significantly increased in those with the sagittal stable vertebra not included in the fixation range (57.1% vs. 18.8%, <i>p</i>=0.020). Other preoperative radiographic parameters were not significantly different. Instability in the distal adjacent LIV disc (adjusted odds ratio, 14.50; <i>p</i>=0.029) and the exclusion of the sagittal stable vertebra from the fixation range (adjusted odds ratio, 5.29; <i>p</i>=0.020) were significant risk factors for DJK occurrence.Conclusions: Regarding spinal reconstruction surgery in patients with osteoporotic vertebral fractures, instability in the distal adjacent LIV disc and the exclusion of the sagittal stable vertebra from the fixation range were risk factors for DJK occurrence in the short term.