Role of the sabo facilities to the sediment discharge in the small basins, especially on the sediment gradient at a sabo-dam

It is important that both of the hard and soft counterplans function well for the prevention of sediment disaster. However, the hard counterplans, for example, sabo-dams are not exactly understood about their role and effect. The author tried to make clear the role, the effect and the limit of sabo-dam for the prevention of disaster with the manual made by the Ministry of Construction and some case studies. From the case studies, the followings became clear. In the northwestern district of Hiroshima Prefecture, where the author had investigated and collected the data, the catchment area of torrent, where debris flow had occurred, and the sediment discharge of unit area were common. However, the proportion of the sediment gradient to the original bed gradient was smaller than the standard arranged by the Ministry of Construction. Though the sabo-dams functioned according to the plan, the number and the scale of the sabo-dams were not enough for the prevention of sediment disaster

Update on perioperative management of patients undergoing surgery for liver cancer

Hepatocellular carcinoma is often accompanied by chronic hepatitis or cirrhosis. Preoperative evaluation of liver function and postoperative nutritional management are critical in patients with hepatocellular carcinoma who undergo liver surgery. Although the incidence of postoperative complications and death has declined in Japan over the last 10 years, postoperative complications have not been fully overcome. Therefore, surgical procedures and perioperative management must be improved. Accurate preoperative evaluations of liver function, nutrition, inflammation, and body skeletal muscle are required. Determination of the optimal surgical procedure should consider not only tumor characteristics but also the physical reserve of the patient. Nutritional management of chronic liver disorders, especially maintaining protein synthesis for postoperative protein/energy, is important. Prophylactic antibiotics are recommended for short-term use within 24 hours after surgery. Abdominal drainage is recommended for patients with cirrhosis who may develop large amounts of ascites, who are at risk of postoperative bleeding, or who may have bile leakage due to a large resection area. Postoperative exercise therapy may improve insulin resistance in patients with chronic liver damage. Implementation of an early/enhanced recovery after surgery program is recommended to reduce biological invasive responses and achieve early independence of physical activity and nutrition intake. We review the latest information on the perioperative management of patients undergoing liver resection for hepatocellular carcinoma

Relationship between slope failure occurrence and precipitation in the areas affected by a strong motion of earthquake

The number of collapses of slope induced by the Geiyo-earthquake occurred in March, 2001 wasoverwhelmingly small to compare with the number by other same degree earthquakes before. However, collapsesof slope are prone to occur relatively in a smaller amount of precipitation after the earthquake. The effectof seismic motion in the Geiyo-earthquake in 2001 was firstly evaluated by the maximum seismic acceleration,duration time of strong seismic motion and the direction of both strong motion and collapses of slope. And then,the amount of precipitation that was related to collapses of slope before and after the Geiyo-earthquake byexamining hourly rainfall and working rainfall (half-value period 72 hours) was considered. As a result, it wasfound that 60 to 80 percentage of precipitation, in which collapses of slope had been prone to occur before theearthquake, would be related to the phenomena such as slope failure and/or stone wall destruction, and landslidesmight occur to all direction regardless of the direction of strong motion over 250 gal in seismic acceleration

Study on the Relationship between the Particle Size of Soil and the Angle of Shear Resistance under the Low Normal Stress

It has been occasionally explained that the angle of shear resistance depends on the soil-particle size. However, the qualitative relationship between the friction coefficient and the particle size is still controversial. To elucidate the effect due to particle size, the samples with some kinds of particle sizes should be prepared by sieving. It is not ideal to get samples by crushing, because the shape of the grain becomes quite different from the original one. Also, the shear experiments should be done under the low stress level, where the particles are not crushed. To obtain the relationship between the particle size of soil and the friction coefficient, the direct shear tests were performed under the low constant normal stress less than ca. 230 gf/cm^2 with some uniform particles of three sizes. As the result, it is found that the friction coefficient increases monotonously with the increase of the particle size. This concludes that the friction coefficient (tan φ) can be expressed by only two factors; mean diameter (d_) and relative density (Dr)

土石流の流動を抑制した自然的要因についての考察

It is very important for the disaster prevention to analyze the factors which influenced on the fluidityof debris flow. We investigated such factors in debris flows occurred around Higashi-Hiroshima in 1999. Weadopted equivalent coefficient of friction and dynamic coefficient of friction to evaluate the fluidity of thedebris flows. As the result of consideration with obtained data, the following things were elucidated: (1) Debrisflow which occurred in the torrent with larger catchment area tends to have large fluidity. (2) In case of eachtorrent, as debris flow moved downwards, dynamic coefficient of friction became smaller. (3) Debris flowstended to lose their fluidity at the places where there were trees, agricultural ponds and tortuosity of the channeletc. (4) The proportion of area occupied by trees is more suitable than the number density of trees as factorsinfluenced on the fluidity of the debris flow. When the proportion of area occupied by trees would becomegreater than some per mills, debris flows at such site could be controlled by the trees

Topographic characteristics to cause landslides and fluidization of their materials : From the debris flow disasters in the northwestern part of Hiroshima Prefecture in 1988

A large number of debris flows occurred in the northwestern part of Hiroshima Prefecture on July 21st in 1988. On the basis of the survey data and the result of analysis on the type of valley in topographic maps and comparison between the contour lines in topographic maps and summit level maps, we explained that the landslides on concave landform occurred easily on steep and undissected valleys and the failures of side slope and waterside tended to occur on dissected valleys. Moreover the courses of debris flows agree well with those that we estimated by the topographic analysis. The method with the topographic analysis in this report could be utilized to make a hazard map for the prevention of debris flow disasters

Study on Distinctive Landslides Induced by an Earthquake

The Kumamoto earthquake of 2016 triggered numerous landslides. One feature of these landslides was fluidic movement of soil mass, which occurred despite little rain having fallen for a long time before the earthquake. To understand this distinctive phenomenon, we analyzed the seismic and soil characteristics of the area and evaluated their association with landslides. The results showed landslides to be concentrated in areas where seismic acceleration exceeded 800 gal. Through soil tests, we found that a mass of clay with abundant Halloysite easily becomes fluid. Therefore we inferred that some landslides were induced by fluidization of such clay layers.本研究の一部は、国土交通省河川砂防技術開発公募の砂防技術分野（平成29～31年度）「大規模地震とそれに伴う地盤の劣化に起因する連鎖複合型土砂災害の発生機構と対策」（研究代表者：丸谷知己北海道大学大学院特任教授）から支援を受けて行うことができました

Assessment of preoperative exercise capacity in hepatocellular carcinoma patients with chronic liver injury undergoing hepatectomy

BACKGROUND: Cardiopulmonary exercise testing measures oxygen uptake at increasing levels of work and predicts cardiopulmonary performance under conditions of stress, such as after abdominal surgery. Dynamic assessment of preoperative exercise capacity may be a useful predictor of postoperative prognosis. This study examined the relationship between preoperative exercise capacity and event-free survival in hepatocellular carcinoma (HCC) patients with chronic liver injury who underwent hepatectomy. METHODS: Sixty-one HCC patients underwent preoperative cardiopulmonary exercise testing to determine their anaerobic threshold (AT). The AT was defined as the break point between carbon dioxide production and oxygen consumption per unit of time (VO(2)). Postoperative events including recurrence of HCC, death, liver failure, and complications of cirrhosis were recorded. Univariate and multivariate analyses were performed to evaluate associations between 35 clinical factors and outcomes, and identify independent prognostic indicators of event-free survival and maintenance of Child-Pugh class. RESULTS: Multivariate analyses identified preoperative branched-chain amino acid/tyrosine ratio (BTR) <5, alanine aminotransferase level ≥42 IU/l, and AT VO(2) <11.5 ml/min/kg as independent prognostic indicators of event-free survival. AT VO(2) <11.5 ml/min/kg and BTR <5 were identified as independent prognostic indicators of maintenance of Child-Pugh class. CONCLUSIONS: This study identified preoperative exercise capacity as an independent prognostic indicator of event-free survival and maintenance of Child-Pugh class in HCC patients with chronic liver injury undergoing hepatectomy