295 research outputs found

    A Semi-analytical Solution for Advection-dispersion Migration of Radionuclides through Two-layered Geologic Media

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    A semi-analytical solution was obtained for a one-dimensional migration of radionuclides in four (or less) member-decay chains with dispersion through a two-layered sorbing medium. The Preferential-release model is applied, in which each element can take a different and time-depending release rate from the waste form. The two types of geologic media concerned were characterized by different retardation factors for each element, the dispersion coefficients, and the ground-water velocities between the two layers. In connection with a long-term safety assessment of geologic disposal of high-level radioactive wastes (HLW), the concentration profiles of radionuclides predicted by the solution can be applied to heterogeneous geologic formations, in which radionuclides migrate through e. g. granite of a host rock followed by subsoil bounded by a surface water body

    Hazard Evaluation on Geologic Disposal of High-Level Radioactive Waste

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    For a long-term safety assessment of geologic disposal of high-level radioactivewaste (HLW), it is necessary to evaluate the potential hazard of radionuclides discharged into the biosphere. Therefore, the result of the safety assessement may heavily depend on this evaluation basis for the potential hazard of radionuclides. The most frequently used measure of the potential hazard is the so-called Ingestion Hazard Index based on the Maximum Permissible Concentration (MPC). Recently, however, the International Commission on Radiological Protection gave the Annual Limits of Intake for workers (ALI). The two different bases of MPC and ALI for the potential hazard bring about considerably different results concerning the safety analysis on the geologic disposal. We derived the explicit form of the solution for the migration of the 4-member decay chain through the one-dimensional sorbing media with dispersion. By applying the solution, it was revealed that in a limited condition of geologic formation, the most dangerous radionuclide in the geologic disposal may be altered by a change of the evaluation basis for the potential hazard. It was also pointed out that the importance of the waste form performance may be much increased by the alteration of the evaluation basis from MPC to AL

    Arthroscopic labral repair concomitantly performed with curved periacetabular osteotomy

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    A 23-year-old female presented with pain in the left hip. Radiological examination showed developmental dysplasia of the hip (DDH) combined with acetabular retroversion and posterior wall deficiency. Findings in the physical examination were coincident with femoroacetabular impingement. At surgery, we performed curved periacetabular osteotomy concomitant with arthroscopic labral repair and osteochondroplasty, simultaneously addressing dysplastic acetabulum and femoroacetabular impingement. The final follow-up examination at 18 months showed satisfactory outcome with the D’Aubigne and Postel hip score of 17/18. In addition to accurate diagnosis, the arthroscopic procedure for associated intra- and peri-articular problems seems to help improve the surgical outcome of periacetabular osteotomy performed for patients with DDH. Level of evidence IV

    Distribution Coefficients of Americium, Neptunium, and Protactinium for Selected Rocks

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    Distribution coefficients (Kᴅ) were measured by a batch technique for sorption-desorption of americium(III), neptunium(V), and protactinium(V) between granite, tuff, or quartz mined in Japan, and water. Measurements were performed at room temperature. The effects of the surface area, pH, and the separation method of solid and liquid phases were studied. The Kᴅ values of americium ranged from 50 to 370000 (mL/g), depending much on the separation methods adopted due to the presence of colloidal particles of americium in solutions. The Kᴅ values of neptunium were small (0.67-13 mL/g), and were little affected by the experimental conditions employed. Protactinium had intermediate values of Kᴅ. The physical adsorption was suggested in the sorption experiments for americium on latex particles

    Geriatric trauma prognosis trends over 10 years: analysis of a nationwide trauma registry

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    Purpose With Japan's population rapidly skewing toward aging, the number of geriatric trauma patients is expected to increase. Since we need to continue to improve the quality of geriatric trauma patient care, this study aimed to evaluate in-hospital mortality trends among geriatric trauma patients in Japan over a recent 10-year period. Methods This was a retrospective cohort study of data from a Japanese nationwide trauma registry (the Japan National Trauma Data Bank) on patients admitted between January 1, 2008 and December 31, 2017. Geriatric patients were defined as those 65 years old and older. The primary outcome was to clarify in-hospital mortality trends and changes over these 10 years. Results We identified 265 268 eligible trauma patients. Excluding those under 65 years old and those with inadequate or unknown age data, missing prognosis, out-of-hospital cardiac arrest, and burns, 107 766 patients were enrolled in this study. The total trauma patient in-hospital mortality trend was evaluated using the Cochran-Armitage test and showed a significant decrease (p= 16) showed a significant decreasing trend (p<0.001) over time (from 26.1% to 14.5%), less-severe trauma patients (ISS <16) did not (p=0.41) (from 2.7% to 2.1%). Mixed logistic regression analysis showed that the number of year patients stayed in the hospital was significantly associated with mortality. Conclusions While recognizing the limitations of the current analysis, our data demonstrated that prognoses for severe trauma patients over 65 years old improved dramatically over these 10 years, especially in those with severe trauma

    Live E! Project: Establishment of Infrastructure Sharing Environmental Information

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    The Live E! project is an open research consortium among industry and academia to explore the platform to share the digital information related with the earth and our living environment. We have getting a lot of low cost sensor nodes with Internet connectivity. The deployment of broad-band and ubiquitous networks will enable autonomous and global digital information sharing over the globe. In this paper, we describe the technical and operational overview of Live E! project, while discussing the objective, such as education, disaster protection/reduction/recovery or busi-ness cases, and goal of this project activity. 1

    Prehospital emergency life-saving technicians promote the survival of trauma patients: A retrospective cohort study

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    Objective Appropriate decisions by medical technicians at a trauma scene may influence a patient's prognosis. Emergency life-saving technicians (ELSTs) are certified specialists trained with the knowledge to provide advanced techniques for prehospital emergency care in Japan. However, the benefit of treatment by ELSTs compared to basic emergency medical technicians (BEMTs) remains unclear. The aim of this study is to determine whether treatment by ELSTs improves outcomes for trauma patients. Methods We retrospectively reviewed the Japan Trauma Data Bank for the years 2004 to 2017. Patients transferred to the hospital directly from the trauma scene and at least 16 years old were included in this study. The following criteria were used to exclude patients; presence of burns, untreatable severe traumas, unknown ELST attendance, and missing prognosis. We compared two groups (ELST group: patients transported by emergency medical services (EMS) with the presence of at least one ELST; BEMT group: patients transported only by BEMTs). Primary outcome was survival to discharge. Secondary outcomes were the need of definitive treatments defined by surgical intervention, intravascular radiology and blood transfusion at the receiving hospital within 24 h. A multivariable logistic regression model was used to calculate odds ratio (OR) and confidence intervals (CI) adjusted by age, sex, revised trauma score, and Injury severity score (ISS). Results Overall survival to discharge did not improve significantly (adjusted OR 1.13, 95% CI 0.99–1.30) with ELST intervention. In-hospital blood transfusion was more frequently required in the ELST group (adjusted OR 1.10, 95% CI 1.01–1.20). Emergency interventions (adjusted OR 1.03, 95% CI 0.97–1.09) were not different between the groups. In stratified analysis, the benefit of ELST attendance for survival was observed among patients with ISS Conclusions Dispatch systems with ELST should be considered for trauma transports, which may benefit elderly or moderate severity trauma groups, with shorter transportation time conditions

    Computer-aided Surgical Planning of Anterior Cruciate Ligament Reconstruction in MR Images

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    AbstractAnterior cruciate ligament (ACL) injury causes knee joint instability, and effects on sports performance. Therefore, ACL reconstruction is essential to keep their high performance. It is well known that the outcome of ACL reconstruction is strongly related to the placement and orientation of the bone tunnel. Therefore, optimization of tunnel drilling technique is an important factor to obtain satisfactory surgical results. Current procedure relies on arthroscopic evaluation and there is a risk of damaging arteries and ligaments during surgery. The damages may reduce the accuracy and reproducibility of ACL reconstruction. As a postoperative evaluation method, a quadrant method has been used to evaluate the placement and orientation of the bone tunnel in X-ray radiography. This study proposes a computer-aided surgical planning system for evaluating ACL insertion site and orientation using magnetic resonance (MR) images. We first introduce MR image based the quadrant method to determine the ACL insertion site for preoperative patients. It also evaluates the 3-D spatial relationship between the planning femoral drilling hole and arteries around the femoral condyle. This system has been applied to ACL injured patients, it may increase the accuracy and reproducibility of ACL bone tunnel, and it can evaluate a risk of damaging the surrounding arteries and ligaments

    Identification of three Early Pleistocene tephras in and around the west part of the Musashino Upland, Tokyo, Northeast Japan

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    In and around the west part of the Musashino Upland, southwest of the Kanto Tectonic Basin, Ob4b-4 (1.62 Ma), Ob4b-1 (1.63 Ma), and Ob3 (1.71-1.78 Ma) tephras in the Kazusa Group, early Quaternary strata, were identified by using characteristic properties such as chemical composition of volcanic glass shards and titanomagnetite, and refractive indices of glass shards, hornblende, cummingtonite, and orthopyroxene. Changes in altitudes of Ob4b-1 identified in four cores and at three outcrops together with those by previous studies indicate geological structure of the Kazusa Group, revealing a gentle northeastward sloping with a gradient of 15/1000 and a prominent discontinuity of the strata along the Tachikawa Fault Zone

    Geriatric Trauma in Patients ≧85 Years Old in an Urban District of Japan

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    Japan's population has been skewing toward the elderly, but the outcomes of advanced elderly trauma are not clear. Here we compared the outcomes of very elderly trauma patients (≧85 years old) with those of 65- to 84-year-old trauma patients. We retrospectively reviewed the medical records of patients treated at Hyogo Emergency Medical Center from August 2010 to August 2016; 631 patients were entered in the study. We divided them into the younger geriatrics (YG group, 65-84 years old: n=534) and older geriatrics (OG group, ≧85 years old: n=97). The group’s patient characteristics, mortality, 1-year survival rate, and Barthel index were tabulated and compared. The patients’ mean age was 75.6±7.5 years. There was no significant difference in mortality between the YG and OG groups (9.6% vs. 15.1%, odds ratio [OR] 1.73; 95% confidence interval [CI] 0.93-3.23, p=0.083). The 1-year survival rate (94.4% vs. 77.8%, OR 0.19, 95% CI 0.07-0.51; p<0.01) and Barthel index (Median score; 100 (IQR: 85-100) vs. 80 (IQR: 15-95), OR 0.98, 95% CI 0.97 to 0.99, p<0.01) differed significantly between the groups. Our study did not find a significant difference in-hospital mortality between patients in the YG group and those in the OG group
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