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Following the Fukushima Daiichi Nuclear Power Plant disaster in March 2011, the Japanese government initiated an unprecedented decontamination programme to remediate 137 Cs-contaminated soils and allow population return. This programme involved the removal of topsoil under farmland and residential land, and its replacement with "fresh soil" composed of granitic saprolite. However, decontamination was limited to these two land uses, without remediating forests, which cover 70 % of the surface area in the affected region. In this unprecedented context, the specific impact of this unique decontamination programme on 137 Cs transfers in river systems remains to be quantified at the catchment scale. In this study, based on the analysis of a sediment core collected in June 2021 in the Mano Dam reservoir draining a decontaminated catchment, the effects of soil decontamination on particle-bound 137 Cs dynamics and sediment source contributions in response to a succession of extreme precipitation events were retrospectively assessed. The sequence of sediment layer deposition and its chronology were reconstructed through the analysis of several diagnostic properties (organic matter, elemental geochemistry, visible colourimetry, granulometry) and contextual information. During abandonment (2011-2016), cropland contribution decreased (31 %). Concurrently, 137 Cs activity and deposition flux decreased (19 and 29%year -1 , respectively). Following decontamination (2017), sediment transfer increased (270 %) in response to increased contributions from decontaminated cropland and "fresh soil" (625 % and 180 % respectively). Meanwhile, forest contributions remained stable. In contrast, 137 Cs activity dropped (65 %), although 137 Cs deposition flux remained constant. Forests acted as a stable source of 137 Cs. Accordingly, 137 Cs deposition flux after decontamination (2016-2021) was similar to that observed during the 5-years period of land abandonment (2011-2016), as a result of the regrowth of spontaneous vegetation over farmland, protecting soil against erosion. Future research should further investigate the impact of longer land abandonment that prevailed in some regions decontaminated lately on the 137 Cs fluxes in the rivers., Competing Interests: Declaration of competing interest Olivier Evrard reports financial support was provided by French National Research Agency. Olivier Evrard reports financial support was provided by French Alternative Energies and Atomic Energy Commission (CEA). Olivier Evrard reports financial support was provided by French National Center for Scientific Research (CNRS). Thomas Chalaux-Clergue reports financial support was provided by French Alternative Energies and Atomic Energy Commission. Thomas Chalaux-Clergue reports financial support was provided by Japan Society for the Promotion of Science (JSPS). Olivier Evrard reports financial support was provided by Environmental Radioactivity Research Network Center (ERAN). If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

Reservoir sediments generally act as a sink for radionuclides derived from nuclear accidents, but under anaerobic conditions, several radionuclides remobilise in bioavailable form from sediments to water columns, which may contribute to the long-term contamination of aquatic products. This study systematically investigated the 137 Cs activities of sediment-pore water, providing a direct evidence of the remobilisation of bioavailable 137 Cs from sediments in two highly contaminated reservoirs affected by the Fukushima Dai-ichi Nuclear Power Plant (FDNPP) accident. We observed that the dissolved 137 Cs activity concentration of pore water (3.0-65.8 Bq L -1 ) was one to two orders of magnitude higher than that of reservoir water. Moreover, the distribution coefficient (K d ) values for the 137 Cs of sediment-pore water (2.6-14 × 10 3  L kg -1 ) decreased with depth. The K d values were significantly and negatively correlated with the concentration of the major 137 Cs competing cation NH 4 + . Our results strongly indicate a competitive ion exchange process between 137 Cs and NH 4 + via a highly selective interaction with the frayed edge sites of phyllosilicate minerals, which is the major reason for the variability of K d values of sediment-pore water, even in the Fukushima case. Additionally, the sediment accumulation rates were relatively high, and the annual depositional rate of exchangeable 137 Cs prevailed over the annual diffusive flux of 137 Cs from the sediment to the overlying water. This finding indicates that even after 10 years since the FDNPP accident, the bioavailable 137 Cs is still continuously supplied from the catchment covered by mountainous forests, and reservoir sediments are a long-term important source of bioavailable 137 Cs in the riverine system. Our findings provide important parameter values for mid- and long-term assessments of the radiation impact of radionuclide discharges to freshwater environments., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier B.V. All rights reserved.)

To investigate the main factors that control the dissolved radiocesium concentration in river water in the area affected by the Fukushima Daiichi nuclear power plant accident, the correlations between the dissolved 137 Cs concentrations at 66 sites normalized to the average 137 Cs inventories for the watersheds with the land use, soil components, topography, and water quality factors were assessed. We found that the topographic wetness index is significantly and positively correlated with the normalized dissolved 137 Cs concentration. Similar positive correlations have been found for European rivers because wetland areas with boggy organic soils that weakly retain 137 Cs are mainly found on plains. However, for small Japanese river watersheds, the building area ratio in the watershed strongly affected the dissolved 137 Cs concentration. One reason for this would be because the high concentrations of solutes, such as K + and dissolved organic carbon, discharged in urban areas would inhibit 137 Cs absorption to soil particles. A multiple regression equation was constructed to predict the normalized dissolved 137 Cs concentration with the topography, land use, soil component, and water quality data as explanatory variables. The best model had the building land use as the primary predictor. When comparing two multiple regression models in which the explanatory variables were limited to (1) the land use and soil composition and (2) the water quality, the water quality model underestimated the high normalized dissolve 137 Cs concentration in urban areas. This poor reproducibility indicates that the dissolved 137 Cs concentration value in urban areas cannot be solely explained by the solid-liquid distribution of 137 Cs owing to the influence of the water quality, but some specific 137 Cs sources in urban areas would control the dissolved 137 Cs concentration., (Copyright © 2019 The Authors. Published by Elsevier B.V. All rights reserved.)

The Fukushima nuclear accident in Japan resulted in the deposition of radiocesium over forested and rural landscapes northwest of the power plant. Although there have been several investigations into the dynamics of contaminated river sediment, less attention has been paid to the sources of deposited particulate matter in dams and reservoirs. In the Fukushima Prefecture, there are 10 significant dams and over a 1000 reservoirs for both agricultural and surface water management. These reservoirs may have trapped a significant volume of radiocesium-contaminated sediment. Therefore, characterizing the sources of contaminated particulate matter is important for the ongoing management of contamination in the region. Accordingly, the composition of particulate matter deposited in the Mano Dam reservoir, approximately 40km northwest of the power plant, was investigated with the analyses and modelling of carbon and nitrogen stable isotope ratios (δ 13 C and δ 15 N), total organic carbon (TOC) and total nitrogen (TN) concentrations. Four sediment cores, with lengths ranging 29-41cm, were sampled in the Mano Dam. Source samples from 46 forest soils, 28 cultivated soils and 25 subsoils were used to determine the source contributions of particulate matter. Carbon and nitrogen parameters were analyzed on all samples and a concentration-dependent distribution modelling approach was used to apportion source contributions. Three of the four cores sampled in the Mano Dam reservoir had distinct radiocesium peaks representative of the initial post-accident wash-off phase. Cultivated sources were responsible for 48±7% of the deposited fine particulate matter whereas forests were modelled to contribute 27±6% and subsoil sources 25±4%. Ongoing decontamination of cultivated sources in the Fukushima region should result in a decrease of contaminated matter deposition in reservoirs., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Purpose: Malalignment of syndesmosis is generally associated with a poor outcome, yet occurs at a high rate in malleolar ankle fractures. In this study, we examine whether malreduction of syndesmosis injury associated with malleolar ankle fracture can be avoided using Weber's three indexes in the mortise view., Materials and Methods: Of 156 patients with malleolar ankle fracture who underwent surgery from December 2012 to March 2016 at two medical facilities, 24 patients who received syndesmotic screw fixation were included in the study. Fractures were Danis-Weber types B and C in 8 (8/134, 6.0%) and 16 (16/22, 72.7%) patients, respectively. Using axial computed tomography (CT), we calculated the difference between injured and non-injured sides for each of three parameters: tibiofibular clear space (TFCS), anterior tibiofibular interval (ATF), and fibular rotation (θ fib ). Malreduction was diagnosed if one or more of the three parameters had an abnormal value. Weber's three indexes in the mortise view on the injured side were used to determine whether reduction of syndesmosis was performed successfully. Consistency between the evaluation of reduction of syndesmosis in axial CT images and reevaluation of mortise views was examined by calculation of sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV)., Results: The rate of malreduction of syndesmosis in axial CT images was 29.2% (7/24). Re-evaluation in the mortise view confirmed malreduction of syndesmosis in six of the seven subjects, all of whom also had malreduction based on axial CT images. The one subject in whom malreduction could not be detected in a mortise view showed an abnormal value only for ATF. Use of the mortise view for perioperative diagnosis had a sensitivity of 0.857, specificity of 1.000, PPV of 1.000, and NPV of 0.944., Conclusion: The results of our study show that malreduction of syndesmosis can be avoided by careful interpretation of intraoperative perspective mortise views based on Weber's three indexes. To increase the diagnostic accuracy further, it is important to detect anteroposterior deviation of the fibula in intraoperative lateral views., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Purpose: There are various types of intertrochanteric fractures that are unstable pertrochanteric fractures of the hip. The aim of this study was to develop a systematic and comprehensive classification of intertrochanteric fractures., Materials and Methods: This study enrolled 74 patients with intertrochanteric fractures treated by us between 2012 and 2015. The fractures were classified using 3D-CT images taken immediately after the fractures occurred based on the course of the lateral fracture line (LFL) that extends through the lateral femoral cortex distal to the vastus ridge of the greater trochanter in the intertrochanteric area. Furthermore, the presence or absence of additional typical fractures was also studied. Then, 4 orthopedic specialists examined the 3D-CT images of 20 patients randomly selected from the 74 patients to evaluate both the inter-rater and intra-rater agreement levels., Results: Intertrochanteric fractures were classified into three types according to the LFL patterns. Type I (41.9%), the Lateral Wall Pattern, has a LFL that extends towards the lateral fiber bundle attachment area of the iliofemoral ligament. Type II (24.3%), the Transverse Pattern, has a LFL that extends towards the medial bundle attachment area. Type III (33.8%), the Reverse Oblique Pattern, has a LFL that extends between the lateral and medial fiber bundle area of the iliofemoral ligament. Each type showed characteristic displacement and was associated with various combinations of typical fractures (fracture across the intertrochanteric line, posteromedial fragment, including the lesser trochanter, posterolateral fragment posterior to the femoral greater trochanter, and banana-shaped big fragment, including both the greater trochanter and the lesser trochanter). The mean κ values for the interobserver and intraobserver agreement levels were 0.77 (0.70-0.85) and 0.76 (0.70-0.85), respectively, which were considered substantial agreement levels., Conclusion: We believe our new classification is a useful communication tool for medical professionals in the diagnosis of fractures., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Purpose: Little is known about whether the pressure adjacent to the ulnar nerve actually is increased in patients with cubital tunnel syndrome or if it is a causative factor. We measured the pressure adjacent to the ulnar nerve in patients with cubital tunnel syndrome during surgery and verified whether or not there was an association with patient age, duration of the disease, motor nerve conduction velocity, and severity of the ulnar nerve neuropathy., Methods: Eight elbows in 8 patients with an average age of 62 years were treated surgically and the extraneural pressures within the cubital tunnel were measured during surgery by using a fiberoptic microtransducer. Pressure was measured 3 times with the elbow fully extended and then 3 times with the elbow flexed 130 degrees. The transducers were placed at 1, 2, and 3 cm distal to the proximal edge of the Osborne ligament. The severity of the neuropathy was evaluated according to Akahori's classification. The ulnar nerve palsy was graded as stage III in 5 patients and as stage IV in 3 patients., Results: The average pressures within the cubital tunnel at 1, 2, and 3 cm distal to the proximal edge of the cubital tunnel retinaculum with the elbow flexed were 105, 29, and 18 mm Hg, respectively. The pressures at 1 and 2 cm distal to the proximal edge of the cubital tunnel retinaculum were significantly higher in elbow flexion than in elbow extension. There was also a positive correlation between the pressure and patient age but this was not significant The pressures correlated significantly with the stage of ulnar nerve neuropathy, motor nerve conduction velocity, and disease duration., Conclusions: The extraneural pressure within the cubital tunnel actually was increased in the patients and compression of the ulnar nerve might be a causative factor of cubital tunnel syndrome.