The Japanese Clinical Practice Guideline for acute kidney injury 2016

Acute kidney injury (AKI) is a syndrome which has a broad range of etiologic factors depending on different clinical settings. Because AKI has significant impacts on prognosis in any clinical settings, early detection and intervention are necessary to improve the outcomes of AKI patients. This clinical guideline for AKI was developed by a multidisciplinary approach with nephrology, intensive care medicine, blood purification, and pediatrics. Of note, clinical practice for AKI management which was widely performed in Japan was also evaluated with comprehensive literature search

Numerical evaluation of mercury concentration by using a distributional multimedia model in the Lake Biwa-Yodo River Basin, Japan

A distributional multimedia model was developed and applied to the Lake Biwa-Yodo River Basin in Japan to reproduce the mercury level in different environmental media. This model was developed based on a Level III steady-state fugacity model, and the space was divided into four environmental media (atmosphere, water, soil, and sediment). The mass transfer of Hg in this model consists of emission, deposition, sedimentation inside one medium, and advection between different media. The dissolution rate and ion exchange equilibrium have also been considered. We estimated Hg emissions in the Lake Biwa-Yodo River Basin from 1957 to 2009 based on the Pollutant Release and Transfer Registry (PRTR) system and the domestic usage of Hg in Japan. The distribution of emission was based on land data, including industrial land area, industrial location, and proportion of the population. The calculated and observed Hg concentrations were compared to evaluate the model. At both large scale and small scale, results showed that the distributional model could predict Hg concentrations in all environmental media. Sediment and soil media showed the accumulation of Hg by showing the higher concentrations than that of other media. In terms of geographical distribution, the urban area and downstream of the river showed high Hg concentrations owing to high Hg emissions. The Hg concentration in the atmosphere was affected by the transboundary pollution. Thus, the distributional multimedia model could reliably calculate the environmental Hg concentration and be utilized in environmental monitoring and management

Numerical Simulation of Heavy Rainfall in August 2014 over Japan and Analysis of Its Sensitivity to Sea Surface Temperature

This study evaluated the performance of the Weather Research and Forecasting (WRF) model version 3.7 for simulating a series of rainfall events in August 2014 over Japan and investigated the impact of uncertainty in sea surface temperature (SST) on simulated rainfall in the record-high precipitation period. WRF simulations for the heavy rainfall were conducted for six different cases. The heavy rainfall events caused by typhoons and rain fronts were similarly accurately reproduced by three cases: the TQW_5km case with grid nudging for air temperature, humidity, and wind and with a horizontal resolution of 5 km; W_5km with wind nudging and 5-km resolution; and W_2.5km with wind nudging and 2.5-km resolution. Because the nudging for air temperature and humidity in TQW_5km suppresses the influence of SST change, and because W_2.5km requires larger computational load, W_5km was selected as the baseline case for a sensitivity analysis of SST. In the sensitivity analysis, SST around Japan was homogeneously changed by 1 K from the original SST data. The analysis showed that the SST increase led to a larger amount of precipitation in the study period in Japan, with the mean increase rate of precipitation being 13 ± 8% K−1. In addition, 99 percentile precipitation (100 mm d−1 in the baseline case) increased by 13% K−1 of SST warming. These results also indicate that an uncertainty of approximately 13% in the simulated heavy rainfall corresponds to an uncertainty of 1 K in SST data around Japan in the study period

Evaluation of Thermal Stratification and Flow Field Reproduced by a Three-Dimensional Hydrodynamic Model in Lake Biwa, Japan

Water temperature near the surface of a lake increases with increasing air temperature, which results in stratification. The strength of stratification substantially influences the transport of water parcels from the surface to the bottom of a lake. In recent years, the stratification in Lake Biwa—the largest freshwater lake in Japan—has been stronger. However, it is difficult to reproduce the stratification well in the simulations. In the present study, we built a hydrodynamic model for the purpose of analyzing the structure of the stratification in detail. Using the model, we evaluated the reproducibility of the seasonal and annual changes of vertical water distribution and flow field in Lake Biwa from 2007 to 2011. The hydrodynamic model results show that the vertical water distribution approximately agrees with the field observations based on the statistical analysis. The seasonal change of thermal stratification is reasonably reproduced by the hydrodynamic model simulations. In the simulation, there are mainly two circulation flows at the surface layer of the lake. The first flows anticlockwise and the second flows clockwise in the northern part of Lake Biwa. In order to compensate for the surface water flow, the water under the thermocline sometimes flows in the opposite direction under each circulation flow

Numerical Analysis of Sensitivity of Structure of the Stratification in Lake Biwa, Japan by Changing Meteorological Elements

Climatic factors such as air temperature and wind speed can affect the structure of stratification in Lake Biwa. In general, the rise in air temperature and the decrease in wind speed weaken the vertical mixing and strengthen the structure of the stratification, which interrupts the transport of the substances. However, how much the change of each climate element can influence the structure of the stratification is not clarified. Therefore, it is important to evaluate the effects of each element on the stratification quantitatively. In the present study, we investigated the effect of the change in air temperature and wind speed on the seasonal change of stratification in Lake Biwa by using a three-dimensional hydrodynamic model. Numerical simulations were carried out for a baseline case using realistic meteorological data from 2007 to 2012 and hypothetical cases using meteorological data with modified air temperature or wind speed for sensitivity analysis. The analysis showed that the increase and decrease in air temperature changed the vertical water temperature uniformly in almost all layers. Thus, the strength of the stratification is hardly changed. The increase and decrease in wind speed, however, altered the water temperature near the surface of the lake, so that it significantly influenced the stratification. The increase in wind speed made the water parcels of the surface layer well mixed, and the decrease in wind speed made the mixed layer thinner

Environmental assessment of lead with spatial gradient in the Lake Biwa-Yodo River basin of Japan: The development of distributional multimedia model

A distributional multimedia model was developed based on one-box model and applied to the Lake Biwa-Yodo River basin in Japan to assess the risk of heavy metal lead. As a useful approach to evaluate the environmental risks, the one-box model could predict the lead concentration by assuming the target area as a homogenies box and calculating mass balance between four environmental media. However, the homogeneity of such wide area assumed by the one-box model is inappropriate. The result of one-box model was not accurate, which cannot show the spatial distribution of pollutants or show the internal transfer of pollutants over time. In this study, the distributional model improved the previous model by incorporating spatial gradients, internal advections and finer meshes. The model was applied to the region from 1957 to 2016 based on the amount of pollutant emission data from the Ministry of Economy's official report, measured meteorological data from the Japan Meteorological Agency, land-use data from the Ministry of Transport, and the river discharge of the hydrology model. The calculated lead concentrations were compared to the observed concentrations at several monitoring stations. The results of this study indicated that the simulated concentration had a gradient inside the region. The area near the emission point and downstream of the river showed relatively high concentrations. For any location, the pollutant concentration is affected by direct emissions, and by adjacent areas due to wind and river discharge. The sediment and water media accumulated more pollutants, and the atmospheric concentration was underestimated in the major pollutant discharge area. This was attributed to underestimation of the distribution of lead emissions in urban areas

Impacts of the Tree Canopy and Chemical Reactions on the Dispersion of Reactive Pollutants in Street Canyons

Traffic-related air pollution in street canyons can cause health problems for pedestrians. In order to clarify the behavior of reactive pollutants, such as NOx and O3, in street canyons, a computational fluid dynamics (CFD) model coupled with a chemistry model and tree canopy model was developed, and then, a set of numerical experiments were performed to investigate the impacts of chemical reactions and aerodynamic effects of trees planted in a canyon. The results were compared with the observation data. Through the results of the numerical experiments designed to simulate a realistic urban street canyon, it was found that chemical reactions have a dominant impact on the NO/NO2 ratio and O3 concentration. While the tree canopy had little impact on the NO/NO2 ratio, it had a moderate impact on the flow field in the canyon and the amount of NOx and O3 in the canyon. In accordance with the aerodynamic effects of tree canopies, the local NOx concentration in the experiments increased and decreased by up to 51% and 11%, respectively. The current findings of this study demonstrate the utility of the proposed model for conducting air quality investigations in urban areas