실제 환경을 고려한 다공질 콘크리트의 내동해성(耐凍害性) 평가

중촌척낭 ( Takuro Nakamura ),굴구경 ( Takashi Horiguchi ),지촌화기 ( Shimura Kazunori ),관원융 ( Takashi Sugawara ) 한국건축시공학회 2008 한국건축시공학회 학술발표대회 논문집 Vol.8 No.2

콘크리트는 연속공극률이 20%에서30%인 특수한 콘크리트이다. 토목공학 분야에서는, 포장재료1)로써는 배수ㆍ투수(透水)기능, 흡음(吸音)기능, 소음감소가 기대되며, 하천 호안( 둑보강)재료2,3)로써는 자연ㆍ생태계 보전, 경관 향상효과가 기대된다. 또한 건축공학 분야에서는 옥상 녹화를 비롯하여 도시의 열섬(heat island)현상의 완화 목적으로도 연구되고 있어, 고도화ㆍ다양화되는 사회자본 정비에 대해, 이와 같은 연속공극의 다기능성 재료의 다공질 콘크리트에 대해 많은 기대를 하고 있다. 다공질 콘크리트는 이와 같은 성능으로 인해, 물가에서의 이용가치가 높고, 한랭지에서 동해(凍害, 동결로 인한 피해)가 염려된다. 하지만 다공질 콘크리트의 내동해성을 평가하는 시험방법, 평가기준이 명확하지 않다. 기존 연구에 따르면, 공극 사이에 가득 차 있는 물이 빙결되는 환경 하에서는, 다공질 콘크리트에 대한 내동해성 평가가 낮지만5),그 이외의 경우에는 비교적 내동해성이 높아질 수 있다고 하며,동결융해 시험의 차이에 따라 평가가 다르게 보고되고 있다. 다공질 콘크리트의 내동해성(耐凍害性)평가에는 주로 재료, 공극률 등에 따른 영향을, 한 가지 동결융해시험방법에 의한 상대평가로 검토하는 연구가 많고, 동일한 배합 시의 복수의 동결융해시험을 실시한 연구는 적다. 본 연구에서는 다공질 콘크리트의 내동해성(耐凍害性) 평가를 목적으로,다공질 콘크리트가 시공되는 환경을 고려하여 4종류의 동결융해시험을 실시하였다. 4종류의 동결융해시험에는, 일본국내에서 폭넓게 채택되고 있는JIS A11488) A법(수중동결 수중융해)/B법(공기중동결 수중융해)및RILEM제안의 CIF9)/CDF10)법을 채용하였다. RILEM제안의 동결융해시험방법은 열역학적인 관점에서 고안된 것으로,지금까지의 동결융해시험의 상대동탄성 계수 변화에서 나아가, 스케일링양, 흡수량 측정을 포함하여, 실제 환경과의 대응, 재현성(再現成) 높이, 실험정밀도 등으로 콘크리트의 내동해성을 더욱 상세하게 검토할 수 있을 것으로 기대되는 시험방법이다11). 본 연구를 통해 얻은 성과를 정리해 보도록 하겠다. (6) JIS A법과 같이, 공극이 강제적으로 물이 가득 차게 되어 얼음이 형성되는 환경에서는 상대동탄성 계수 저하가 현저하며, 커다란 균열과 함께 붕괴하는 것을 확인하였다. 이런 환경에서는 AE콘크리트에 비해 내동해성이 낮으므로 시공할 때 이를 고려할 필요가 있다. (7) JIS B법 및 RILEM CIF/CDF법과 같이, 동결 시에 공극내에서 얼음이 형성되지 않는 환경에서는 내동해성 평가가 크게 향상되고, 특히 RILEM CIF/CDF법에서는 상대 동탄성 계수의 저하는 확인되지 않았다. (8) JIS A/B법에서, 다공질 콘크리트의 내동해성은 세골재를 혼합하거나, 굵은골재의 치수를 낮게 하는 등, 배합을 조정함으로써 개선이 가능한 것으로 확인되었다. (9) JIS B법과 RILEM CIF법의 결과, 다공질 콘크리트에서도 동결속도나 동결융해 사이클 수가 상대동탄성 계수 저하에 영향을 주며, paste막 두께가 얇은 다공질 콘크리트는 일반 콘크리트에 비해 그 영향도 큰 것으로 생각된다. (10) RILEM CIF/CDF시험 결과, 일반 콘크리트에서는 염분환경에서 스케일링에 의한 표면열화가 격렬해지지만, 다공질 콘크리트에서는 현저한 열화가 보이지 않으며, 염분공급 하에서의 표면열화에 비해 높은 내동해성을 유지하는 것을 확인하였다. Porous concrete has large continuous voids of 20.30 % by volume, and this concrete is attractive as environmental material in Japan i.e. permeable road pavement, river bank protection with vegetation and green roof system which influence thermal environment. It is necessary to confirm the frost resistance when constructing porous concrete structure in cold region. However applicable test method and evaluation criterion of porous concrete has not defined yet. Therefore, the object of this study is to investigate the frost resistance of porous concrete and this investigation attempts to address this concern by comparing 4 kinds of specified freezing and thawing tests methods (JIS A1148 procedure A/B and RILEM CIF/CDF test) in consideration of actual environment. RILEM freeze.thaw tests are different from JIS A1148 freeze.thaw tests, which are widely adopted for evaluating the frost resistance of conventional concrete in Japan, in water absorption, cooling rate, length of freezing and thawing period, and number of freezing and thawing cycles. RILEM CIF test measures internal damage and is primarily applicable for pure frost attack. CDF test is appropriate for freeze.thaw and de.icing salt attack. JIS A1148 procedure A/B showed extremely low frost resistance of porous concrete if the large continuous voids were filled with water and the ice expansion in the large continuous voids set in during cooling. Frost resistance of porous concrete was improved by mixing coarse aggregate (G7) which particle size is smaller and fine aggregate in JIS freezing and thawing tests. RILEM CIF/CDF test showed that freeze.thaw and de.icing resistance of porous concrete was seems to be superior in that of conventional concrete.

Differences in Hematological and Clinical Features Between Essential Thrombocythemia Cases With JAK2- or CALR-Mutations

Yoko Kubuki,Kotaro Shide,Takuro Kameda,Takumi Yamaji,Masaaki Sekine,Ayako Kamiunten,Keiichi Akizuki,Haruko Shimoda,Yuki Tahira,Kenichi Nakamura,Hiroo Abe,Tadashi Miike,Hisayoshi Iwakiri,Yoshihiro Taha 대한진단검사의학회 2017 Annals of Laboratory Medicine Vol.37 No.2

Dear Editor, Essential thrombocythemia (ET) is a myeloproliferative neoplasm (MPN) that primarily involves the megakaryocytic lineage, and is characterized by increased numbers of large, mature megakaryocytes in bone marrow as well as sustained thrombocytosis. Mutations in JAK2 or calreticulin (CALR) are present in about 50% and 25% of patients with ET, respectively, and these mutations are thought to drive MPN [1]. CALR and JAK2 mutations are mutually exclusive in MPNs [1]. Compared with patients with JAK2-mutated ET, patients with CALR-mutated ET have lower Hb levels and lower numbers of granulocytes, but higher numbers of platelets [2-6]. The CALR-mutated patients also have a lower incidence of thrombosis during their clinical course. Genetic background such as race may influence the risk of thrombosis, and recent study reported that Japanese ET patients with JAK2 mutation had a higher cumulative incidence of thrombosis than those with CALR mutations, although the differences were not significant [6]. Therefore, we analyzed the impact of JAK2 and CALR mutations on clinical features and thrombotic events in Japanese patients with ET.

Expression Analyses of A, C and D-class MADS-box Genes in Phalaenopsis sp. (Orchidaceae)

In-Ja Song,Toru Nakamura,Takuro Ito,Tatsuya Fukuda,Jun Yokoyama,Hiroaki Ichikawa,Yoh Horikawa,Toshiaki Kameya,Akira Kanno 한국원예학회 2006 한국원예학회 기타간행물 Vol.- No.-

Pancreatic Compression during Lymph Node Dissection in Laparoscopic Gastrectomy: Possible Cause of Pancreatic Leakage

Satoshi Ida,Naoki Hiki,Takeaki Ishizawa,Yugo Kuriki,Mako Kamiya,Yasuteru Urano,Takuro Nakamura,Yasuo Tsuda,Yosuke Kano,Koshi Kumagai,Souya Nunobe,Manabu Ohashi,Takeshi Sano 대한위암학회 2018 Journal of gastric cancer Vol.18 No.2

Purpose: Postoperative pancreatic fistula is a serious and fatal complication of gastrectomy for gastric cancer. Blunt trauma to the parenchyma of the pancreas can result from an assistant's forceps compressing and retracting the pancreas, which in turn may result in pancreatic juice leakage. However, no published studies have focused on blunt trauma to the pancreas during laparoscopic surgery. Our aim was to investigate the relationship between compression of the pancreas and pancreatic juice leakage in a swine model. Materials and Methods: Three female pigs were used in this study. The pancreas was gently compressed dorsally for 15 minutes laparoscopically with gauze grasped with forceps. Pancreatic juice leakage was visualized by fluorescence imaging after topical administration of chymotrypsin-activatable fluorophore in real time. Amylase concentrations in ascites collected at specified times was measured. In addition, pancreatic tissue was fixed with formalin, and the histology of the compressed sites was evaluated. Results: Fluorescence imaging enabled visualization of pancreatic juice leaking into ascites around the pancreas. Median concentrations of pancreatic amylase in ascites increased from 46 U/L preoperatively to 12,509 U/L 4 hours after compression. Histological examination of tissues obtained 4 hours after compression revealed necrotic pancreatic acinar cells extending from the surface to deep within the pancreas and infiltration of inflammatory cells. Conclusions: Pancreatic compression by the assistant's forceps can contribute to pancreatic juice leakage. These findings will help to improve the procedure for lymph node dissection around the pancreas during laparoscopic gastrectomy.

VIBRATION-TESTING-BASED DEVELOPMENT OF SPACE BOOM FOR A 50KG-CLASS MICRO-SATELLITE

Takeshi Sakai,Katsu Kakiuchi,Yusuke Sonoda,Yoshihiko Sugiyama,Hisayoshi Honda,Yosuke Nakamura,Koji Nakaya,Takuro Kawamae 한국소음진동공학회 2008 한국소음진동공학회 국제학술대회논문집 Vol.2008 No.7

Pancreatic Compression during Lymph Node Dissection in Laparoscopic Gastrectomy: Possible Cause of Pancreatic Leakage

Ida, Satoshi,Hiki, Naoki,Ishizawa, Takeaki,Kuriki, Yugo,Kamiya, Mako,Urano, Yasuteru,Nakamura, Takuro,Tsuda, Yasuo,Kano, Yosuke,Kumagai, Koshi,Nunobe, Souya,Ohashi, Manabu,Sano, Takeshi The Korean Gastric Cancer Association 2018 Journal of gastric cancer Vol.18 No.2

Purpose: Postoperative pancreatic fistula is a serious and fatal complication of gastrectomy for gastric cancer. Blunt trauma to the parenchyma of the pancreas can result from an assistant's forceps compressing and retracting the pancreas, which in turn may result in pancreatic juice leakage. However, no published studies have focused on blunt trauma to the pancreas during laparoscopic surgery. Our aim was to investigate the relationship between compression of the pancreas and pancreatic juice leakage in a swine model. Materials and Methods: Three female pigs were used in this study. The pancreas was gently compressed dorsally for 15 minutes laparoscopically with gauze grasped with forceps. Pancreatic juice leakage was visualized by fluorescence imaging after topical administration of chymotrypsin-activatable fluorophore in real time. Amylase concentrations in ascites collected at specified times was measured. In addition, pancreatic tissue was fixed with formalin, and the histology of the compressed sites was evaluated. Results: Fluorescence imaging enabled visualization of pancreatic juice leaking into ascites around the pancreas. Median concentrations of pancreatic amylase in ascites increased from 46 U/L preoperatively to 12,509 U/L 4 hours after compression. Histological examination of tissues obtained 4 hours after compression revealed necrotic pancreatic acinar cells extending from the surface to deep within the pancreas and infiltration of inflammatory cells. Conclusions: Pancreatic compression by the assistant's forceps can contribute to pancreatic juice leakage. These findings will help to improve the procedure for lymph node dissection around the pancreas during laparoscopic gastrectomy.