Shear Resistance of Sands under Undrained Condition and Potential for Rapid Flow Phenomena by Means of Ring Shear Tests

長距離せんだんが可能なリングせん断試験および三軸圧縮試験において発揮される砂の非排水せん断挙動の解明を目的に, 細粒系さおよび風化火成岩資料を対象に実験を実施した。また, 排水時の摩擦係数と見かけの摩擦係数の比を「高速流動ポテンシャル」と定義した。リングせん断試験だけでなく三軸圧縮試験においても, せん断が進み試料中にせん断面が形成されると, 粒子に破砕が進行し間隙水圧が上昇するため, 高い高速流動現象ポテンシャルを示すことが示された。Shear resistance of two kinds of sands (fine silica and weathered granitic sands) mobilized within shear zone subjected to large shear displacement is examined. The undrained shear strengths at steady state of the specimens formed over the wide range of initial void ratios by ring shear tests are directly compared with those from the undrained triaxial compression tests. The steady state strengths in ring shear tests were smaller than those in triaxial compression tests due to grain crushing. While, small steady state strengths were observed by triaxial compression tests on dense fine silica sand in which there were clearshear surfaces and shear deformation must be concentrated on these surfaces to generate excess pore pressure. To express extent of apparent reduction of internal friction, the new parameter (Pf) was proposed as ratio of drained internal friction angle to apparent friction angle. Potential for rapid flow phenomena of employed two kinds of sands are clearly evaluated by Pf over the wide range of void ratio.長距離せんだんが可能なリングせん断試験および三軸圧縮試験において発揮される砂の非排水せん断挙動の解明を目的に,細粒系さおよび風化火成岩資料を対象に実験を実施した。また,排水時の摩擦係数と見かけの摩擦係数の比を「高速流動ポテンシャル」と定義した。リングせん断試験だけでなく三軸圧縮試験においても,せん断が進み試料中にせん断面が形成されると,粒子に破砕が進行し間隙水圧が上昇するため,高い高速流動現象ポテンシャルを示すことが示された。Shear resistance of two kinds of sands (fine silica and weathered granitic sands) mobilized within shear zone subjected to large shear displacement is examined. The undrained shear strengths at steady state of the specimens formed over the wide range of initial void ratios by ring shear tests are directly compared with those from the undrained triaxial compression tests. The steady state strengths in ring shear tests were smaller than those in triaxial compression tests due to grain crushing. While, small steady state strengths were observed by triaxial compression tests on dense fine silica sand in which there were clearshear surfaces and shear deformation must be concentrated on these surfaces to generate excess pore pressure. To express extent of apparent reduction of internal friction, the new parameter (Pf) was proposed as ratio of drained internal friction angle to apparent friction angle. Potential for rapid flow phenomena of employed two kinds of sands are clearly evaluated by Pf over the wide range of void ratio

Macrophage numbers in the marginal area of sarcomas predict clinical prognosis

Even when treated comprehensively by surgery, chemotherapy, and radiotherapy, soft-tissue sarcoma has an unfavorable outcome. Because soft-tissue sarcoma is rare, it is the subject of fewer clinicopathological studies, which are important for clarifying pathophysiology. Here, we examined tumor-associated macrophages in the intratumoral and marginal areas of sarcomas to increase our knowledge about the pathophysiology. Seventy-five sarcoma specimens (not limited to a single histological type), resected at our institution, were collected, and the number of CD68-, CD163-, and CD204-positive macrophages in the intratumoral and marginal areas was counted. We then performed statistical analysis to examine links between macrophage numbers, clinical factors, and outcomes. A high number of macrophages positive for all markers in both areas was associated with worse disease-free survival (DFS). Next, we divided cases according to the FNCLCC classification (Grade 1 and Grades 2/3). In the Grade 1 group, there was no significant association between macrophage number and DFS. However, in the Grade 2/3 group, high numbers of CD163- and CD204-positive macrophages in the marginal area were associated with poor DFS. By contrast, there was no significant difference between the groups with respect to high or low numbers of CD68-, CD163-, or CD204-positive macrophages in the intratumoral area. Multivariate analysis identified the number of CD163- and CD204-positive macrophages in the marginal area as an independent prognostic factor. Macrophage numbers in the marginal area of soft-tissue sarcoma may better reflect clinical behavior

Langerhans cell histiocytosis of the sternum

We report a rare case of Langerhans cell histiocytosis involving the sternum. The patient was a 12-year-old girl presenting with anterior chest pain and swelling. Radiographs and computed tomography showed an osteolytic lesion in the sternum. Technetium bone scintigraphy revealed increased uptakes in the sternum, the greater trochanter of the right femur, and the right distal tibia. Incisional biopsy for the sternum lesion was performed, and the histopathologic diagnosis was Langerhans cell histiocytosis. She was treated with chemotherapy and the symptoms disappeared