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Forefront of dental application of titanium
Yutaka Oda 대한치과재료학회 2014 대한치과재료학회지 Vol.41 No.S
Titanium and titanium alloys, based on their excellent physicochemical properties and superior biocompatibility, appear to be suitable for medical devices. In addition to the original titanium properties, many functional enhancement such as shape-memory function, low elastic modulus, super-hydrophilic and antibacterial effect has been achieved by alloying and surface modification. Titanium has been around since 1790 and gets it name from the Greek God “Titan”. Until the mid-1940s, 150 years since the discovery of the ore, it could not refining to create the “industrial” market. It is a new metal that has only 70-year history, compared to the iron (2000-3000 years ago). For decades titanium was considered an “aerospace metal” and was used exclusively in this application. Beginning that Linkow has introduced a blade-type implants in the 1960s, resulted the widespread use of titanium implants in current dentistry. In the 1970s, Andreasen et al. found that the alloyed nickel and titanium exhibit shape memory and superelastic function. Nickel titanium wire is commonly used in orthodontic. Study of titanium began to increase in the dental materials science from the 1980s. Titanium casting in dentistry has now almost reached the stage to compete with dental casting using conventional base-metal alloys. Research efforts to overcome some problems associated with titanium casting, including the development of new titanium alloys suitable for dental use, have been continued. On the other hand, the progress of the computer technology brings the innovation of the fabrication method, and dental CAD/CAM is developing from cutting process into the additive manufacturing technologies. It is still in the research stage to the fabrication of dental prosthesis by additive manufacturing of titanium and titanium alloys, but the application also is entering the field of view. Titanium has enabled dental use with surrounding technological advances. Titanium is active metal originally and different from the noble metals such as gold alloy. It is found titanium can be easily corroded in the presence of an alkaline peroxide and the presence of an acid to form a complex ion such as hydrofluoric acid. Titanium and its alloys as viable options to more traditional noble and base metal alloys, but careful selection of processing methods and considering their characteristics are necessary to ensure success. While reviewing the development of titanium and titanium alloys, I’d like to introduce the forefront of titanium research in dentistry.
Metachronous Gastric Cancer Following Curative Endoscopic Resection of Early Gastric Cancer
Seiichiro Abe,Ichiro Oda,Takeyoshi Minagawa,Masau Sekiguchi,Satoru Nonaka,Haruhisa Suzuki,Shigetaka Yoshinaga,Amit Bhatt,Yutaka Saito 대한소화기내시경학회 2018 Clinical Endoscopy Vol.51 No.3
This review article summarizes knowledge about metachronous gastric cancer (MGC) occurring after curative endoscopic resection (ER)of early gastric cancer (EGC), treatment outcomes of patients who developed MGC, and efficacy of Helicobacter pylori eradication toprevent MGC. The incidence of MGC following curative ER increases over time and is higher than in patients undergoing gastrectomy. Increasing age and multifocal EGC are independent risk factors for developing MGC. An MGC following curative ER is usually a small(<20 mm) and differentiated intramucosal cancer. Most MGC lesions are found at an early stage on semiannual or annual surveillanceendoscopy and are successfully treated by further ER, with excellent long-term outcomes. Eradication of H. pylori may reduce the riskof MGC following ER of EGC, but further prospective studies with long-term outcomes are required. Surveillance endoscopy followinggastric ER should be continued indefinitely, due to the risk of MGC even after successful H. pylori eradication. Risk stratification andtailored endoscopic surveillance schedules need to be developed.
Hiroyuki Takamaru,Shigetaka Yoshinaga,Hajime Takisawa,Ichiro Oda,Hitoshi Katai,Shigeki Sekine,Kazuhiro Taniguchi,Yutaka Saito 거트앤리버 소화기연관학회협의회 2020 Gut and Liver Vol.14 No.5
Background/Aims: The accurate assessment of the depth of invasion of early gastric cancer (EGC) is critical to determine the most appropriate treatment option. However, it is difficult to distinguish shallow submucosal (SM1) invasion from deeper submucosal (SM2) invasion. We investigated the diagnostic performance of endoscopic ultrasonography (EUS) using a miniature probe for EGC with suspected SM invasion. Methods: From April 2008 to June 2018, EGCs with suspected SM invasion were analyzed retrospectively. The EGCs examined by a 20 MHz high-frequency miniature probe was included in our study. Esophago-gastric junction cancers and patients treated by chemotherapy before resection were excluded. The sensitivity and specificity for the detection of SM2 invasion by EUS were compared with those of white light imaging (WLI). Additionally, factors related to depth underestimation or overestimation were investigated using multivariate analysis. Results: A total of 278 EGCs in 259 patients were included in the final analysis. The sensitivity and specificity for SM2 or deeper by EUS were 73.7% (87/118) and 74.4% (119/160), respectively. The sensitivity and specificity by WLI were 47.5% (56/118) and 68.1% (109/160), respectively. The sensitivity of EUS was significantly superior to that of conventional endoscopy (p<0.01). Multivariate analysis revealed that an anterior location of the EGC was an independent risk factor for underestimation by EUS (odds ratio, 3.3; 95% confidence interval, 1.1 to 9.8; p=0.03). Conclusions: The depth diagnostic performance for EGCs with suspected SM invasion using EUS was satisfactory and superior to that of conventional endoscopy. Additionally, it is important to recognize factors that may lead to misdiagnosis in those lesions.
Mai Ego Makiguchi,Seiichiro Abe,Yutaka Okagawa,Satoru Nonaka,Haruhisa Suzuki,Shigetaka Yoshinaga,Ichiro Oda,Okamoto Ryuta,Yutaka Saito 대한소화기내시경학회 2022 Clinical Endoscopy Vol.55 No.2
Background/Aims: This study aimed to assess the efficacy of a novel aerosol-exposure protection (AP) mask in preventingcoronavirus disease in healthcare professionals during upper gastrointestinal endoscopy and to evaluate its clinical feasibility. Methods: In Study 1, three healthy volunteers volitionally coughed with and without the AP mask in a cleanroom. Microparticleswere visualized and counted with a specific measurement system and compared with and without the AP mask. In Study 2,30 patients underwent endoscopic resection with the AP mask covering the face, and the SpO2 was measured throughout theprocedure. Results: In Study 1, the median number of microparticles in volunteers 1, 2, and 3 with and without the AP mask was 8.5 and 110.0,7.0 and 51.5, and 8.0 and 95.0, respectively (p<0.01). Using the AP mask, microparticles were reduced by approximately 92%. Themedian distances of microparticle scattering without the AP mask were 60, 0, and 68 in volunteers 1, 2, and 3, respectively. In Study 2,the mean SpO2 was 96.3%, and desaturation occurred in three patients. Conclusion: The AP mask could provide protection from aerosol exposure and can be safely used for endoscopy in clinical practice.
Japanese Kindergarten Teachers' Belief on Intellectual and Social Development
Bernard Spodek,Hiroshi Ashida,Riyo Kadota,Masatoshi Suzuki,Kiyomi Akita,Yutaka Oda,Takako Noguchi 한국유아교육학회 2004 INTERNATIONAL JOURNAL OF EARLY CHILDHOOD EDUCATION Vol.10 No.1
Early childhood education in Japan has traditionally been described by researchers from abroad in dichotomous terms, for example, “individualism vs. collectivism,” “formal and intellectual learning vs. affective learning.” “independence vs. interdependence.” This study illustrates the facilitation of intellectual and social development by Japanese kindergarten teachers not as two opposing ideas, instead, it shows intellectual and social development as complementing each other as children develop intelligence and independence.Building on Tobin’s methodology and video recording of kindergartens, a new approach portrays teachers’ personal philosophies on early childhood education and instruction. Although the methodology can and will be improved, its basic validity has been affirmed.
( Wataru Ando ),( Hiroaki Yokomori ),( Nobuhiro Tsutsui ),( Eigoro Yamanouchi ),( Yutaka Suzuki ),( Masaya Oda ),( Yutaka Inagaki ),( Katsuya Otori ),( Isao Okazaki ) 대한간학회 2018 Clinical and Molecular Hepatology(대한간학회지) Vol.24 No.1
Background/Aims: Nonalcoholic steatohepatitis (NASH) is prevalent in both economically developed and developing countries. Twenty percent of NASH progresses to cirrhosis with/without hepatocellular carcinoma, and there is an urgent need to find biomarkers for early diagnosis and monitoring progression of the disease. Using immunohistochemical and immunoelectron microscopic examination we previously reported that expression of matrix metalloproteinase-1 (MMP- 1) increased in monocytes, Kupffer cells and hepatic stellate cells in early stage NASH. The present study investigated whether serum MMP-1 levels reflect disease activity and pharmaceutical effects in NASH patients. Methods: We measured the serum levels of MMPs, tissue inhibitors of metalloproteinases (TIMPs), and several cytokines/ chemokines in patients with histologically proven early and advanced stages of NASH and compared them with those in healthy controls. Results: Serum MMP-1 levels in stage 1 fibrosis, but not in the more advanced fibrosis stages, were significantly higher than in healthy controls (P=0.019). There was no correlation between serum MMP-1 level and fibrosis stage. Serum MMP- 1 levels in NASH patients represented disease activity estimated by serum aminotransferase values during the followup period. In contrast, MMP-2, MMP-9 and TIMPs did not change with disease activity. Consistent with the finding that MMP-1 is expressed predominantly in monocytes and Kupffer cells, serum levels of monocyte chemotactic protein-1 and granulocyte-colony stimulating factor were significantly increased in NASH with stage 1 fibrosis. Conclusions: These results suggest that serum MMP-1 levels represent disease activity and may serve as a potential biomarker for monitoring the progression of NASH. (Clin Mol Hepatol 2018;24:61-76)