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Plastic Anisotropy in Aluminium Drawn Tubes
Takahashi, Hiroshi,Moro, Junji,Tsuchida, Shin 대한금속재료학회(대한금속학회) 1998 METALS AND MATERIALS International Vol.4 No.3
Developments of plastic anisotropy in aluminium tubes are investigated experimentally and theoretically. As-received drawn tubes are tensioned or twisted to get speciments having different anisotropies. The tubes are cut and extended into flat sheets. The surfaces are removed mechanically and electorochemically into half thickness. The anisotropy is evaluated by flow stress and r-value of tensile tests in various directions in a sheet. Crystallographic textures are detected by X-ray diffraction, from which crystal orientations are determined and then incorporated into the finite element polycrystal model. The predicted results of anisotropy by numerical tensile tests are compared with the above experiments. If a tube specimen is isotropic, its flow stress of simple torsion should be less than that of simple tension. However, the present as-received drawn tube shows the reverse tendency. This fact is confirmed theoretically on the basis of averaged anisotropy through thichness.
Efficacy and safety of cold forceps polypectomy utilizing the jumbo cup: a prospective study
( Hiroshi Hasegawa ),( Shigeki Bamba ),( Kenichiro Takahashi ),( Masaki Murata ),( Taketo Otsuka ),( Hiroshi Matsumoto ),( Takehide Fujimoto ),( Rie Osaki ),( Hirotsugu Imaeda ),( Atsushi Nishida ),( 대한장연구학회 2019 Intestinal Research Vol.17 No.2
Background/Aims: There are few prospective studies on cold forceps polypectomy (CFP) using jumbo cup forceps. Therefore, we examined patients with diminutive polyps (5 mm or smaller) treated with CFP using jumbo cup forceps to achieve an ade-noma-free colon and also assessed the safety of the procedure and the recurrence rate of missed or residual polyp after CFP by performing follow-up colo-noscopy 1 year later. Methods: We included patients with up to 5 adenomas removed at initial colonoscopy and analyzed data from a total of 361 patients with 573 adenomas. One-year follow-up colonoscopy was performed in 165 patients, at which 251 lesions were confirmed. Results: The one-bite resection rate with CFP was highest for lesions 3 mm or smaller and decreased significantly with increasing lesion size. Post-procedural hemorrhage was observed in 1 of 573 lesions (0.17%). No perforation was noted. The definite recurrence rate was 0.8% (2/251 lesions). The probable recurrence rate, which was defined as recurrence in the same colorectal segment, was 17%. Adenoma-free colon was achieved in 55% of patients at initial resection. Multivariate analysis revealed that achievement of an adenoma-free colon was significantly associated with number of adenomas and years of endoscopic experience. Conclusions: CFP using jumbo biopsy forceps was safe and showed a high one-bite resection rate for diminutive lesions of 3 mm or smaller. The low definite recurrence rate confirms the reliability of CFP using jumbo biopsy forceps. Number of adenomas and years of endoscopic experience were key factors in achieving an adenoma-free colon. (Intest Res 2019;17:265-272.)
Anti-apoptotic effect by Bcl-2 in UVB-irradiated keratinocytes.
Takahashi, Hidetoshi,Honma, Masaru,Ishida-Yamamoto, Akemi,Namikawa, Kazuhiko,Miwa, Akiko,Okado, Haruo,Kiyama, Hiroshi,Iizuka, Hajime Korean Society of Photoscience 2002 Journal of Photosciences Vol.9 No.2
Bcl-2 is a member of large bcl-2 family and protects cells from apoptosis. Using bcl-2-expressing adenovirus vector (Ad-bc1-2), we investigated the effect of bc1-2 on UVB-induced apoptosis. Adenovirus vector efficiently introduced bc1-2 gene in cultured normal mouse keratinocytes (NMK cells); almost all NMK cells (lx10$^{6}$ ) were transfected at Ixl0$^{8}$ PFU/ml. Bcl-2-transfected NMK cells were significantly resistant to UVB-induced apoptosis with the suppressive effect dependent on bcl-2-expression level. Following UVB irradiation caspase 8, 3, 9 activities were stimulated in NMK cells, while in bc1-2-transfected cells, only caspase 8, but not caspase 3 or 9 activities were stimulated. In order to investigate the effect of bc1-2 in vivo, topical application of Ad-bc1-2 on tape-stripped mouse skin was performed. Following the application, Bc1-2 was efficiently overexpressed in almost all viable keratinocytes. The expression was transient with the maximal expression of Bc1-2 at 1st day following the application of lxl0$^{9}$ PFU in 200ml. The introduced Bc1-2 remained at least for 6 days. UVB irradiation (1250 J/m$^2$) induced apoptosis within 12 h and the maximal effect was observed at 24 h in control mouse skin. Bc1-2-transfected mice skin were resistant to UVB-induced apoptosis. Topical application of empty adenovirus vector alone had no effect on Bc1-2 expression or UVB-induced apoptosis. These results indicate that adenovirus vector is an efficient gene delivery system into keratinocytes and that Bcl-2 is a potent inhibitor of UVB-induced apoptosis both in vitro and in vivo.
Hiroshi Nakagawara,Kenji Yamao,Takuji Gotoda,Daiichiro Kikuta,Akinori Takei,Kunio Iwatsuka,Toshimi Takahashi,Masahiro Ogawa,Akihiro Henmi,Makio Kobayashi,Mitsuhiko Moriyama 소화기인터벤션의학회 2019 International journal of gastrointestinal interven Vol.8 No.2
Background: Endoscopic-guided placement of metal stents for unresectable malignant hilar biliary obstruction (UMHBO) is performed using partial stent-in-stent or side-by-side (SBS) techniques. The latter involves placing sequential stents within the bile duct. Excessive dilation of the bile duct during stent placement can have serious effects on the surrounding organs.Methods: This study details seven cases of SBS placement of 8.0 mm metal stents for UMHBO. Histopathological examinations were performed to identify the effects on the bile duct and surrounding tissues.Results: The mean post-placement diameter of the bile ducts was 13.86 mm, and no compression necrosis or thrombi were observed in surrounding tissues. Cholangitis occurred in five cases, and death occurred as a result of cholecystitis in one case. Conclusion: The use of 8.0-mm stents for SBS is unlikely to have major negative effects on peribiliary tissues and blood vessels. However, post-placement cholecystitis can result in increased mortality; thus, gallbladder drainage should be considered.