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Toshiaki Taniike,Shougo Takahashi,Toru Wada,Iku Kouzai,Minoru Terano 한국고분자학회 2010 Macromolecular Research Vol.18 No.9
The dispersion state of surface Ti species is one of the most important factors affecting the polymerization properties of MgCl2-supported heterogeneous Ziegler-Natta catalysts. In this paper, ethylene-propylene copolymerization was carried out using a novel Ziegler-Natta model catalyst with “isolated” and “clustered” TiCl3 molecules on MgCl2. At a lower ethylene/propylene feed ratio, the dispersion state of the Ti species strongly affected both the composition and sequence distribution of the copolymers. The “isolated” Ti species gave a relatively random copolymer, and clustering of Ti species enhanced the bulkiness. The addition of an external donor basically deteriorated the random copolymerization character of the “isolated Ti species but the degree of deterioration depended on the type of donors. On the other hand, the balance between the monomer feed and consumption dominated the copolymerization performance at a higher ethylene/propylene feed ratio to obscure the effects of the dispersion state.
Role of Dispersion State of Ti Species in Deactivation of MgCl2-Supported Ziegler-Natta Catalysts
Toshiaki Taniike,Toru Wada,Iku Kouzai,Shougo Takahashi,Minoru Terano 한국고분자학회 2010 Macromolecular Research Vol.18 No.9
The deactivation behaviors of TiCl3/MgCl2 model catalysts with molecularly dispersed TiCl3 were investigated to clarify the role of the dispersion state of the Ti species in the deactivation of MgCl2-supported Ziegler-Natta (ZN) catalysts for propylene and ethylene polymerization. The propylene and ethylene polymerization activities of clustered Ti species supported on MgCl2 were approximately one tenth of those of isolated Ti species, which is indicative of the significance of the aggregation of Ti species in the deactivation of ZN catalysts for olefin polymerization. Moreover, the time-course depression of monomer consumption for the clustered Ti species was slower than that for the isolated Ti species in propylene polymerization, whereas the dispersion state barely affected the depression rate in ethylene polymerization. The reduction rate of the Ti species was concluded to be important for the time-course depression of propylene consumption, whereas ethylene polymerization was insensitive to the oxidation state of the Ti species.
Yuichi Tomiki,Jun Aoki,Shunsuke Motegi,Rina Takahashi,Toshiaki Hagiwara,Yu Okazawa,Kosuke Mizukoshi,Masaya Kawai,Shinya Munakata,Shun Ishiyama,Kiichi Sugimoto,Kazuhiro Sakamoto 대한소화기내시경학회 2019 Clinical Endoscopy Vol.52 No.6
Background/Aims: Sclerotherapy with aluminum potassium sulfate and tannic acid (ALTA) has a potent effect on internalhemorrhoids. In this retrospective study, we compared the effects of endoscopic ALTA therapy and standard ALTA therapy. Methods: We investigated patients who underwent treatment for internal hemorrhoids at our institution between 2014 and 2016. Theywere divided into a standard ALTA group (n=33, treated using proctoscopy) and an endoscopic ALTA group (n=48). We compared theclinical findings between the 2 groups. Results: There were no intergroup differences in background factors. The mean ALTA dose was 21.9±7.2 mL and 17.8±3.4 mL inthe standard and endoscopic ALTA groups, respectively (p<0.01). Adverse events occurred in 4 patients (12.1%) from the standardALTA group and 6 patients (12.5%) from the endoscopic ALTA group. In both groups, the patients reported good satisfaction withthe therapeutic effect at 1 month after the procedure. Hemorrhoids recurred in 2 patients (6.3%) from the standard ALTA group and 4patients (8.3%) from the endoscopic ALTA group. Conclusions: Endoscopic ALTA sclerotherapy is equivalent to standard ALTA therapy in terms of efficacy, adverse events, andrecurrence. Therefore, it is a useful non-surgical option for patients with internal hemorrhoids who prefer a less invasive treatment.
Shinji Tanishima,Tokumitsu Mihara,Atsushi Tanida,Chikako Takeda,Masaaki Murata,Toshiaki Takahashi,Koji Yamane,Tsugutake Morishita,Yasuo Morio,Hiroyuki Ishii,Satoru Fukata,Yoshiro Nanjo,Yuki Hamamoto,T 대한척추외과학회 2019 Asian Spine Journal Vol.13 No.3
Study Design: Multicenter, prospective study. Purpose: To investigate the effects of diabetes mellitus (DM) on surgical outcomes in patients with cervical myelopathy. Overview of Literature: To date, few studies have investigated the influence of postoperative blood glucose or glycated hemoglobin (HbA1c) levels on surgical outcomes. Methods: The participants were patients who underwent surgery for the treatment of cervical spondylotic myelopathy and ossification of the posterior longitudinal ligament. The 61 cases were evaluated preoperatively and 1 year postoperatively using the Japanese Orthopaedic Association (JOA) scores and the JOA Cervical Myelopathy Evaluation Questionnaire (JOACMEQ). The study variables included fasting blood glucose and HbA1c levels measured preoperatively and at 1 week, 4 weeks, and 1 year postoperatively; the F-wave conduction velocity, latency, rate of occurrence, and M-wave latency in the ulnar and tibial nerves were measured preoperatively and at 1 year postoperatively. The patients were divided into a group without diabetes (N group, 42 patients) and a group with diabetes (DM group, 19 patients). We then assessed the associations between the surgical outcomes and each of the study variables. Results: JOA scores significantly improved in both groups; however, no significant between-group differences were found. There was no significant improvement in the JOACMEQ scores, which assessed cervical function, upper and lower limb function, and bladder function in both groups. We then subdivided the DM group into those with a good control of HbA1c after 1 year (DMG group, 12 patients) and those with HbA1c deterioration after 1 year (DMB group, seven patients), prior to comparing the surgical outcomes. The JOACMEQ scores for upper and lower limb function significantly improved in the DMG group (p<0.01). Compared with the DMB group, there were no significant increases in upper or lower limb function scores in the DMG group. Conclusions: Poor glycemic control might prevent postoperative functional recovery of the spinal cord.
Kazuhide Inage,Sumihisa Orita,Yawara Eguchi,Yasuhiro Shiga,Masao Koda,Yasuchika Aoki,Toshiaki Kotani,Tsutomu Akazawa,Takeo Furuya,Junichi Nakamura,Hiroshi Takahashi,Miyako Suzuki-Narita,Satoshi Maki,S 연세대학교의과대학 2021 Yonsei medical journal Vol.62 No.9
Purpose: In this multicenter retrospective observational study, we examined the early effects of romosozumab in patients with severeosteoporosis in terms of time-course changes in bone metabolism marker, improvement in bone density, and adverse effects. Materials and Methods: Patients with severe osteoporosis were included. We investigated the progress of TRACP 5b and P1NPbefore and 1–2 months after the administration of romosozumab. We also investigated the bone density of lumbar spine, femoralneck, and the entire femur, measured by the DXA method, before and 5–7 months after the administration of romosozumab. Results: A total of 70 patients (7 males and 63 females, age 75.0±3.6 years) participated in this study. Significant improvements inTRACP 5b and P1NP levels were observed before and 1–2 months after romosozumab administration. The average bone densityof lumbar spine, femoral neck, and the entire femur were measured before and 5–7 months after romosozumab administration;and a significant increase only observed in the lumbar spine. Conclusion: Consistent with the findings of previous clinical studies, romosozumab has both bone formation-enhancing andbone resorption effects (dual effect). In addition, romosozumab also demonstrated improvement in bone density from the earlyphase after the administration, though the result was only seen in the lumbar spine.