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Sleep-disordered breathing (SDB) is associated with an increased risk of adverse events in patients with heart failure (HF); however, its impact in patients implanted with a left ventricular assist device (LVAD) remains unclear. We aimed to investigate the prevalence of SDB in patients with LVAD and its impact on their clinical outcomes. Fifty consecutive patients with LVAD who underwent portable sleep monitoring between September 2017 and April 2018 were prospectively enrolled, and they were followed up for 170 ± 36 days. According to their respiratory disturbance indexes (RDIs), they were categorized into the SDB group (RDI ≥ 15, n = 12) and the non-SDB group (RDI 15, n = 38). The incidence of adverse events during the follow-up period was investigated after enrollment. Multivariate logistic regression analysis revealed significant differences in SDB in LVAD-implanted patients in terms of the logarithmic transformation brain natriuretic peptide (BNP) values (p = 0.005). The optimal BNP cut-off value for SDB prediction in LVAD-implanted patients was 300 pg/mL (sensitivity: 58.3%, specificity: 94.7%). During follow-up, ventricular tachyarrhythmias (VTas) occurred significantly more frequently in the SDB group (4 [33%] vs. 2 [5%] patients, p = 0.02); Atrial tachyarrhythmia (ATa) also tended to occur more frequently in the SDB group (2 [25%] vs. 2 [2%] patients, p = 0.07). SBD was prevalent in 24% of the LVAD-implanted patients with advanced HF. Furthermore, SDB was significantly associated with high BNP levels and was also potentially associated with subsequent incidence of VTa in patients with LVAD.

Acquired coarctation of the aorta (CoA) following total aortic arch replacement (TAR) is a rare complication inducing left ventricular (LV) dysfunction probably due to increased LV afterload and secondary hypertension caused by increased upper body and decreased renal blood flow. We describe a case of a 35-year-old male who developed atypical CoA with severe LV dysfunction with LV ejection fraction of 10%, but without secondary hypertension after TAR using conventional elephant trunk (ET) technique for acute aortic dissection. Computed tomography revealed near-occlusive CoA due to narrowed distal ET. Because the myocardial histological findings were mild, and he had no cardiac failure history, we determined that LV function might be reversible. He underwent thoracic endovascular aortic repair (TEVAR), resulting in restored LV function. However, as the descending aortic false lumen distally to the end of ET was rapidly dilated, probably due to increased cardiac output and lower body blood flow, he underwent descending aortic replacement 3 months after TEVAR. In conclusion, a narrowed distal ET may cause LV dysfunction early after TAR, even without secondary hypertension. TEVAR may be a useful therapeutic option for a narrowed distant ET but can induce distal aortic dilatation.

Acute calcineurin inhibitor (CNI) nephrotoxicity is a common complication associated with CNI exposure. However, it can be difficult to diagnose. Herein, we report a case of acute CNI nephrotoxicity after heart transplant that was visualized using kidney Doppler ultrasonography.A 38-year-old female patient underwent heart transplant 5 years after the use of left ventricular assist device support because of advanced heart failure due to ischemic cardiomyopathy. Corticosteroids, tacrolimus, and mycophenolate mofetil were administered as immunosuppressive regimens postoperatively. The patient gradually developed kidney dysfunction despite a favorable perioperative clinical course and hemodynamics. Serum creatinine increased to 1.89 mg/dL on postoperative day (POD) 9, and the kidney Doppler ultrasonography examination showed severely reduced blood flow in the renal and renal segmental arteries, indicating acute CNI nephrotoxicity due to vasoconstriction of the renal arterioles. After the cessation of tacrolimus, kidney function returned to baseline levels within 2 days, and the kidney Doppler ultrasonography examination on POD 19 revealed a significant increase in blood flow in the renal and renal segmental arteries. Basiliximab followed by everolimus were administered as alternative immunosuppressants. No organic stenosis of the renal artery was detected on the kidney magnetic resonance angiography, and the patient was discharged on POD 51, without any other adverse events, including rejection.Although CNIs are widely used after heart transplant, acute nephrotoxicity should always be considered. After heart transplant, a kidney Doppler ultrasonography should be performed routinely and promptly if there are any clinical manifestations related to kidney function.

Background Implantable left ventricular assist devices (LVAD) have improved quality of life and survival in patients with advanced heart failure. However, LVAD-specific infections and predicting which patients will develop infections remain challenging. This study investigated whether changes in body mass index (BMI) during hospitalization following LVAD implantation are associated with LVAD-specific infections within 1 year of implantation.Methods and Results:Patients (n=135) undergoing LVAD implantation were retrospectively divided into 2 groups based on changes in BMI from LVAD implantation to discharge: those with and without decreases in BMI. Each group was further subdivided according to baseline albumin concentrations (high [>3.7 g/dL] and low [≤3.7 g/dL]). Twenty patients developed LVAD-specific infections within 1 year. Receiver operating characteristic curve analysis resulted in a ∆BMI cut-off of less than -0.128 kg/m2. In multivariate analysis, younger patients and those with decreases in BMI had significantly higher rates of LVAD-specific infection (P=0.010 and P=0.035, respectively). LVAD-specific infection rates were significantly higher for patients with low albumin and decreases in BMI than for patients with low albumin but no decrease in BMI. Conclusions Decreases in BMI during hospitalization after LVAD implantation and younger age were independently associated with LVAD-specific infection within 1 year. Strict patient management may be needed to avoid decreases in BMI during hospitalization after LVAD implantation, particularly in patients with low baseline albumin concentrations.

Background In Japan, patients with heart failure who have a paracorporeal left ventricular assist device (pLVAD) and cannot be weaned from the VAD may undergo conversion to implantable continuous-flow LVAD (iLVAD) via a bridge-to-bridge (BTB) strategy for bridge-to-transplantation (BTT). This study aimed to evaluate the real-world clinical status of BTB strategies. Methods Among 134 patients who underwent iLVAD implantation for BTT, 34 patients underwent conversion from pLVAD to iLVAD (BTB group) and 100 patients underwent iLVAD implantation primarily (primary iLVAD group). The clinical characteristics and outcomes were compared between the two groups. Results No significant difference was found in the overall survival between the two groups (p = 0.26; log-rank test). However, the 1-year survival rate and the 1-year freedom from the composite events of death, stroke, systemic infection, and bleeding rate were lower in the BTB group than in the primary iLVAD group (survival rate, 88.2% vs. 99.0%, p = 0.0040; composite event-free survival rate, 26.1% vs. 49.8%, p = 0.030; log-rank test). Multivariate analysis indicated that the BTB strategy [hazard ratio (HR) 1.70, 95% confidence intervals (CI) 1.03–2.72; p=0.036] and serum total bilirubin levels at iLVAD implantation [HR 1.31, 95% CI 1.00–1.65; p=0.043] were independent predictors of 1-year composite events. Conclusions The BTB strategy is useful in providing long-term survival in patients with acute critical diseases. However, the early mortality rate after conversion is higher in patients who underwent the BTB strategy.

Background Appropriate indications and protocols for induction therapy using basiliximab have not been fully established in heart transplant (HTx) recipients. This study elucidated the influence of induction therapy using basiliximab along with delayed tacrolimus (Tac) initiation on the outcomes of high-risk HTx recipients.Methods and Results:A total of 86 HTx recipients treated with Tac-based immunosuppression were retrospectively reviewed. Induction therapy was administered to 46 recipients (53.5%) with impaired renal function, pre-transplant sensitization, and recipient- and donor-related risk factors (Induction group). Tac administration was delayed in the Induction group. Induction group subjects showed a lower cumulative incidence of acute cellular rejection grade ≥1R after propensity score adjustment, but this was not significantly different (hazard ratio [HR]: 0.63, 95% confidence interval [CI]: 0.37-1.08, P=0.093). Renal dysfunction in the Induction group significantly improved 6 months post-transplantation (P=0.029). The cumulative incidence of bacterial or fungal infections was significantly higher in the Induction group (HR: 10.6, 95% CI: 1.28-88.2, P=0.029). Conclusions These results suggest that basiliximab-based induction therapy with delayed Tac initiation may suppress mild acute cellular rejection and improve renal function in recipients with renal dysfunction, resulting in its non-inferior outcome, even in high-risk patients, when applied to the appropriate recipients. However, it should be carefully considered in recipients at a high risk of bacterial and fungal infections.

Background Continuous-flow left ventricular assist device (CF-LVAD) substantially improves survival in endstage heart failure patients. However, bleeding complications are common after CF-LVAD implantation and in some cases, re-exploration for bleeding is needed. We aimed to investigate the incidence, timing, and risk factors of bleeding requiring re-exploration after CF-LVAD implantation.Methods and Results:We retrospectively reviewed 162 consecutive patients (age 43±13 years, 71% men) who underwent CF-LVAD implantation (HeartMateII 119, Jarvik2000 15, HVAD 13, EVAHEART 10, DuraHeart 5) from January 2012 to June 2019. During follow-up [median 662 days, interquartile range (IQR) 364-1,116 days], 35 (21.6%) experienced re-exploration for bleeding. The median timing of re-exploration was 6 (IQR 1-10) days. In the multivariate logistic regression analysis, postoperative platelet count was an independent predictor for re-exploration for bleeding after CF-LVAD implantation (per 104/μL: odds ratio 0.83, 95% confidence interval 0.74-0.93, P=0.002). Patients who experienced re-exploration for bleeding had a significantly worse survival rate than patients who did not (at 4 years, 73.6% vs. 90.1%, P=0.039). Conclusions Re-exploration for bleeding is prevalent after CF-LVAD implantation, especially in patients with low postoperative platelet counts. As bleeding requiring re-exploration is associated with poor prognosis, risk stratification using the postoperative platelet count may be beneficial for these patients.

We present computational flow analysis of a vertical-axis wind turbine (VAWT) that has been proposed to also serve as a tsunami shelter. In addition to the three-blade rotor, the turbine has four support columns at the periphery. The columns support the turbine rotor and the shelter. Computational challenges encountered in flow analysis of wind turbines in general include accurate representation of the turbine geometry, multiscale unsteady flow, and moving-boundary flow associated with the rotor motion. The tsunami-shelter VAWT, because of its rather high geometric complexity, poses the additional challenge of reaching high accuracy in turbine-geometry representation and flow solution when the geometry is so complex. We address the challenges with a space–time (ST) computational method that integrates three special ST methods around the core, ST Variational Multiscale (ST-VMS) method, and mesh generation and improvement methods. The three special methods are the ST Slip Interface (ST-SI) method, ST Isogeometric Analysis (ST-IGA), and the ST/NURBS Mesh Update Method (STNMUM). The ST-discretization feature of the integrated method provides higher-order accuracy compared to standard discretization methods. The VMS feature addresses the computational challenges associated with the multiscale nature of the unsteady flow. The moving-mesh feature of the ST framework enables high-resolution computation near the blades. The ST-SI enables moving-mesh computation of the spinning rotor. The mesh covering the rotor spins with it, and the SI between the spinning mesh and the rest of the mesh accurately connects the two sides of the solution. The ST-IGA enables more accurate representation of the blade and other turbine geometries and increased accuracy in the flow solution. The STNMUM enables exact representation of the mesh rotation. A general-purpose NURBS mesh generation method makes it easier to deal with the complex turbine geometry. The quality of the mesh generated with this method is improved with a mesh relaxation method based on fiber-reinforced hyperelasticity and optimized zero-stress state. We present computations for the 2D and 3D cases. The computations show the effectiveness of our ST and mesh generation and relaxation methods in flow analysis of the tsunami-shelter VAWT.

Background Although recent attention to palliative care for patients with cardiovascular diseases has been increasing, there are no specific recommendations on detailed palliative care practices. We proceed on a discussion of the appropriateness and applicability of potential quality indicators for acute cardiovascular diseases according to our previous systematic review. Methods We created a multidisciplinary panel of 20 team members and 7 external validation clinicians composed of clinical cardiologists, a nutritionist, a physiotherapist, a clinical psychologist, a critical and emergent care specialist, a catheterization specialist, a primary care specialist, a palliative care specialist, and nurses. After crafting potential indicators, we performed a Delphi rating, ranging from “1 = minimum” to “9 = maximum”. The criterion for the adoption of candidate indicators was set at a total mean score of seven or more. Finally, we subcategorized these indicators into several domains by using exploratory factor analysis. Results Sixteen of the panel members (80%) were men (age, 49.5 ± 13.7 years old). Among the initial 32 indicators, consensus was initially reached on total 23 indicators (71.8%), which were then summarized into 21 measures by selecting relatively feasible time variations. The major domains were “symptom palliation” and “supporting the decision-making process”. Factor analysis could not find optimal model. Narratively-developed seven sub-categories included “presence of palliative care team”, “patient-family relationship”, “multidisciplinary team approach”, “policy of approaching patients”, “symptom screening and management”, “presence of ethical review board”, “collecting and providing information for decision-maker”, and “determination of treatment strategy and the sharing of the care team’s decision”. Conclusion In this study we developed 21 quality indicators, which were categorized into 2 major domains and 7 sub-categories. These indicators might be useful for many healthcare providers in the initiation and enhancement of palliative care practices for acute cardiovascular diseases in Japan.

BACKGROUND Sarcopenia is characterized by progressive loss of skeletal muscle and has frequently been associated with poor clinical outcomes in patients with advanced heart failure (HF). The urinary creatinine excretion rate (CER) index is an easily measured marker of muscle mass, but its predictive capacity for mortality and cerebrovascular events has not been investigated in patients with a continuous-flow implantable left ventricular assist device (CF-iLVAD).Methods and Results:We retrospectively reviewed 147 patients (mean [±SD] age 43.7±12.5 years, 106 male) who underwent CF-iLVAD implantation between April 2011 and June 2019. CER indices in 24-h urine samples before CF-iLVAD implantation were determined. Over a median follow-up of 2.3 years, there were 10 (6.8%) deaths and 43 (29.3%) cerebrovascular events. Patients were divided into 2 groups (low and high CER index) according to the median CER index in men and women (i.e., 13.71 and 12.06 mg·kg-1·day-1, respectively). Mortality and intracranial hemorrhage rates after CF-iLVAD implantation were significantly higher in the low than high CER index group (mortality 12.3% vs. 1.4% [P

Background The therapeutic strategy for giant cell myocarditis (GCM) remains controversial, so we reviewed the clinical status of Japanese patients with GCM.Methods and Results:We retrospectively reviewed 6 consecutive patients with GCM requiring percutaneous mechanical circulatory support (p-MCS), with 3 further requiring ventricular assist devices. One patient died during p-MCS. Cardiac function improved in the other 5 with immunosuppressive therapy, but only 3 patients treated with dual immunosuppressants, including cyclosporine (CyA), achieved >1-year survival. Conclusions The prognosis of patients with fulminant GCM is poor, but a treatment that combines MCS and early administration of CyA-based immunosuppressants will be useful.

Gastrointestinal bleeding (GIB) is among the major complications affecting implantable continuous-flow left ventricular assist device (iLVAD) recipients and is the major cause of re-hospitalization. GIB in iLVAD recipients is sometimes critical, and controlling bleeding using conventional approaches is difficult. A 35-year-old woman developed refractory GIB from multiple gastric polyps and de novo angiodysplasia after Jarvik2000® iLVAD implantation. Discontinuation of anticoagulation and antiplatelet therapies had little effect on GIB; thus, multiple endoscopic hemostatic therapies were performed. However, bleeding recurred several times, and red blood cell (RBC) transfusion in large volumes was required for progressive anemia. Furthermore, the von Willebrand factor (VWF) multimer analysis revealed loss of the high-molecular weight multimer, which may have resulted from the high-speed rotation of the axial-flow LVAD pump. To supplement VWF, cryoprecipitate was administered, but it was effective for only several days. Finally, the patient was treated with octreotide, a somatostatin analog, on post-operative day 58. After starting octreotide, tarry stool gradually decreased, and progression of anemia slowed down within the first 14 days of treatment; thus, the total RBC transfusion volume was reduced without additional hemostatic interventions, including cryoprecipitate administration. The patient developed mediastinitis on post-operative day 68 and died of sepsis on post-operative day 72. There was no adverse effect associated with octreotide use. Although the observation period was short, octreotide appears to be useful for resolving recurrent GIB after iLVAD implantation and reducing blood transfusions.

Background Because of aggressive immunosuppression, heart transplant recipients have a high risk of de novo malignancy, which is a major cause of death and worse prognosis, regardless of the type. However, the impact of de novo malignancy on Japanese heart transplant recipients is unknown. Methods We analyzed 103 Japanese heart transplant recipients over 18-years-old at the time of transplantation between April 1999 and April 2017. Patient characteristics and prognosis were compared between heart transplant recipients with or without de novo malignancy after heart transplantation (HTx). Additionally, univariate and multivariate analyses for the risk factors of de novo malignancy after HTx were performed. Results De novo malignancy developed in 7 patients (6.8%; post-transplant lymphoproliferative disorders, n = 3; Bowen's disease, n = 1; colon cancer, n = 2; bladder cancer, n = 1). Follow-up time and previous antibody mediated rejection (AMR) ≥ grade 1 were risk factors of de novo malignancy after HTx in multivariate analysis (OR: 1.19, 95% CI: 1.00–1.42, p = 0.043; and OR: 10.7, 95% CI: 1.37–83.68, p = 0.038, respectively). History of malignancy was a potential risk factor, albeit not significant (OR: 23.05, 95% CI: 0.99–534.53, p = 0.071). The survival rates in patients with de novo malignancy was significantly lower than in those without de novo malignancy (3-year survival rate: 100% versus 67%, p = 0.0025). Conclusions Long follow-up time and previous AMR ≥ grade 1 were risk factors of de novo malignancy after HTx. Japanese heart transplant recipients with de novo malignancy have worse prognosis; therefore, screening examinations are important for early diagnosis.

Background: The relationship between outcome and trigger in takotsubo syndrome (TTS) has been recently discussed, but the data are still limited. Methods and Results: We enrolled 745 consecutive patients with TTS from the Tokyo Cardiovascular Care Unit Network registry. The patients were divided into 4 groups based on trigger: (1) medical illness, 202 (27%); (2) physical activity, trauma and injury, 54 (7%); (3) emotional trigger, 199 (27%); and (4) unidentifiable trigger, 290 (39%). Compared with other groups, the medical illness group had the lowest percentage of female patients (68%, 85%, 89%, and 79%, respectively; P

A 72-year-old man with a history of chronic obstructive pulmonary disease(COPD)was diagnosed with type 3 gastric cancer at the posterior wall of the gastric body. Although there was no distant metastasis in preoperative imaging tests, pulmonary function test revealed severe obstructive ventilatory impairment, suggesting that the patient had high risks of perioperative pulmonary complications. After treatment for COPD and preoperative pulmonary rehabilitation under hospitalization for 2 weeks, laparoscopic distal gastrectomy plus D2 lymphadenectomy plus Roux-en-Y reconstruction was performed. The patient showed stable respiratory condition postoperatively, and was discharged from hospital on postoperative day 12 without serious postoperative complications. It was suggested that preoperative pulmonary rehabilitation reduced postoperative pulmonary complications and allowed safe surgery in patients with severe COPD.

Left ventricular assist device (LVAD) therapy is increasingly used in patients with end-stage heart failure. However, LVADs are associated with challenges, especially in the presence of a cardiac implantable electronic device. Although a leadless pacemaker (PM), the Micra™ Transcatheter Pacing System, can be used with LVADs, data regarding HeartMate 3™ LVAD are limited. In this report, we present a patient with a HeartMate 3™ LVAD who underwent successful leadless PM implantation after the removal of an infected cardiac resynchronization therapy defibrillator.

Background During these 2 decades (1999-2019), many therapeutic strategies have been developed in the field of heart transplant (HTx) to improve post-HTx outcomes. In the present study, 116 consecutive HTx adults between 1999 and 2019 were retrospectively reviewed to evaluate the influences of a therapeutic modification on post HTx outcomes.Methods and Results:Patient survival, functional status and hemodynamics after HTx and modification of therapeutic strategies were reviewed. The overall cumulative survival rate at 10 and 20 years post-HTx was 96.4 and 76.7%, respectively. There were no significant differences in survival rate or exercise tolerance after HTx between extracorporeal and implantable continuous flow-LVAD. Post-HTx patient survival in patients, irrespective of the donor risk factors such as donor age, low LVEF, history of cardiac arrest, was equivalent across cohorts, while longer TIT and higher inotrope dosage prior to procurement surgery were significant risk factors for survival. In 21 patients given everolimus (EVL) due to renal dysfunction, serum creatinine significantly decreased 1 year after initiation. In 22 patients given EVL due to transplant coronary vasculopathy (TCAV), maximum intimal thickness significantly decreased 3 years after initiation. Conclusions The analysis of a 20-year single-center experience with HTx in Japan shows encouraging improved results when several therapeutic modifications were made; for example, proactive use of donor hearts declined by other centers and the use of EVL in patients with renal dysfunction and TCAV.

Background: Although the typical apical form of Takotsubo syndrome and anterior acute myocardial infarction have similar electrocardiographic and echocardiographic presentations, data on the clinical differences between the two disorders are limited. Methods: Using the Tokyo Cardiovascular Care Unit network registry, we identified patients hospitalised with apical Takotsubo syndrome ( n=540; 2010–2014) or anterior acute myocardial infarction ( n=2,806; 2013–2014) and created 522 age and sex-matched pairs (mean age 74.1 years; women 78.5%). We compared the clinical characteristics and inhospital outcomes between the two groups. Results: On admission, patients with apical Takotsubo syndrome showed a lower body mass index, less frequent chest pain/tightness, lower systolic blood pressure, higher heart rate, lower creatine kinase, higher C-reactive protein and brain natriuretic peptide, and less frequent ST-elevation than patients with anterior acute myocardial infarction. Patients with apical Takotsubo syndrome received catecholamine (12.8% vs. 24.5%, PConclusions: This study found that cardiac and non-cardiac mortality risks differed significantly between apical Takotsubo syndrome and anterior acute myocardial infarction. Our findings underscore the importance of differentiating between the two disorders for appropriate management.

Many of the challenges encountered in computational analysis of wind turbines and turbomachinery are being addressed by the Arbitrary Lagrangian–Eulerian (ALE) and Space–Time (ST) Variational Multiscale (VMS) methods and isogeometric discretization. The computational challenges include turbulent rotational flows, complex geometries, moving boundaries and interfaces, such as the rotor motion, and the fluid–structure interaction (FSI), such as the FSI between the wind turbine blade and the air. The core computational methods are the ALE-VMS and ST-VMS methods. These are supplemented with special methods like the Slip Interface (SI) method and ST Isogeometric Analysis with NURBS basis functions in time. We describe the core and special methods and present, as examples of challenging computations performed, computational analysis of horizontal- and vertical-axis wind turbines and flow-driven string dynamics in pumps.

Gastrointestinal bleeding (GIB) is among the major complications affecting implantable continuous-flow left ventricular assist device (iLVAD) recipients and is the major cause of re-hospitalization. GIB in iLVAD recipients is sometimes critical, and controlling bleeding using conventional approaches is difficult. A 35-year-old woman developed refractory GIB from multiple gastric polyps and de novo angiodysplasia after Jarvik2000

The challenges encountered in computational analysis of wind turbines and turbomachinery include turbulent rotational flows, complex geometries, moving boundaries and interfaces, such as the rotor motion, and the fluid-structure interaction (FSI), such as the FSI between the wind turbine blade and the air. The Arbitrary Lagrangian-Eulerian (ALE) and Space-Time (ST) Variational Multiscale (VMS) methods and isogeometric discretization have been effective in addressing these challenges. The ALE-VMS and ST-VMS serve as core computational methods. They are supplemented with special methods like the Slip Interface (SI) method and ST Isogeometric Analysis with NURBS basis functions in time. We describe the core and special methods and present, as examples of challenging computations performed, computational analysis of horizontal and vertical-axis wind turbines and flow-driven This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium provided the original work is properly cited.

Low left ventricular ejection fraction (EF) is known as one of the risk factors for occurrence of acute heart failure (AHF) in patients with takotsubo syndrome (TTS). While, because of basal hyperkinetic contraction, EF using Teichholz formula (tEF), which can be easily calculated by systolic and

We present the space–time variational multiscale (ST-VMS) method for flow computations with slip interfaces (ST-SI). The method is intended for fluid–structure interaction (FSI) analysis where one or more of the subdomains contain spinning structures, such as the rotor of a wind turbine, and the subdomains are covered by meshes that do not match at the interface and have slip between them. The mesh covering a subdomain with the spinning structure spins with it, thus maintaining the high-resolution representation of the boundary layers near the structure. The starting point in the development of the method is the version of the arbitrary Lagrangian–Eulerian VMS (ALE-VMS) method designed for computations with "sliding interfaces". Interface terms similar to those in the ALE-VMS version are added to the ST-VMS formulation to account for the compatibility conditions for the velocity and stress. In addition to having a high-resolution representation of the boundary layers, because the ST framework allows NURBS functions in temporal representation of the structure motion, we have exact representation of the circular paths associated with the spinning. The ST-SI method includes versions for cases where the SI is between fluid and solid domains with weakly-imposed Dirichlet conditions for the fluid and for cases where the SI is between a thin porous structure and the fluid on its two sides. Test computations with 2D and 3D models of a vertical-axis wind turbine show the effectiveness of the ST-SI method.

This paper provides validation results of SWAT4, the revised version of SWAT3.1, by the analysis of PIE data of MOX fuel irradiated in a pressurized water reactor. SWAT4 is a system that combines the point burnup system ORIGEN2 and neutron transport calculation solvers, the continuous energy Monte Carlo code MVP or MCNP5, and the deterministic neutronics calculation code SRAC2006. The calculation results of SWAT4 have generally same trends with the case of UO2 fuel analyses. For major uranium and plutonium isotopes, deviations less than 5% were obtained. This means that SWAT4 has the same accuracy to predict isotopic compositions of irradiated MOX fuel with the case of UO2 fuel. The radial distribution of isotopes in a pellet was also analyzed, whose results were compared with that measured by SIMS. SWAT4 predicted well the isotope and burnup distributions in an irradiated MOX pellet.

The value of the burnup is one of the most important parameters of samples taken by post-irradiation examination (PIE). Generally, it is evaluated by the Neodymium-148 method. Precise evaluation of the burnup value requires: (1) an effective fission yield of 148 Nd; (2) neutron capture reactions of 147 Nd and 148 Nd; (3) a conversion factor from fissions per initial heavy metal to the burnup unit GWd/t. In this study, the burnup values of the PIE data from Mihama-3 and Genkai-1 PWRs, which were taken by the Japan Atomic Energy Research Institute, were re-evaluated using more accurate corrections for each of these three items. The PIE data were then re-analyzed using SWAT and SWAT2 code systems with JENDL-3.3 library. The re-evaluation of the effective fission yield of 148 Nd has an effect of 1.5–2.0% on burnup values. Considering the neutron capture reactions of 147 Nd and 148 Nd removes dependence of C/E values of 148 Nd on the burnup value. The conversion factor from FIMA(%) to GWd/t changes according to the burnup value. Its effect on the burnup evaluation is small for samples having burnup of larger than 30 GWd/t. The analyses using the corrected burnup values showed that the calculated 148 Nd concentrations and the PIE data is approximately 1%, whereas this was 3–5% in prior analyses. This analysis indicates that the burnup values of samples from Mihama-3 and Genkai-1 PWRs should be corrected by 2–3%. The effect of re-evaluation of the burnup value on the neutron multiplication factor is an approximately 0.6% change in PIE samples having the burnup of larger than 30 GWd/t. Finally, comparison between calculation results using a single pin-cell model and an assembly model is carried out. Because the results agreed with each other within a few percent, we concluded that the single pin-cell model is suitable for the analysis of PIE samples and that the underestimation of plutonium isotopes, which occurred in the previous analyses, does not result from a geometry model.

Burnup is an important parameter in criticality safety evaluations of spent nuclear fuel in which burnup credit is taken into account. The Neodymium-148 method is widely used to evaluate the burnup of post irradiation examination (PIE) samples, and it is well known for its good accuracy. However, accuracy of the evaluated burnup values may be affected by the neutron capture reaction of 147Nd and 148Nd. Moreover, in the analysis of PIE data from a PWR, the calculation results of 148Nd have more than a 1% deviation from the experiment. In this study, the contribution of neutron capture reactions of 147Nd and 148Nd to the amount of 148Nd is discussed. The PIE data analyses using new evaluation of 147Nd capture cross section show that the JENDL-3.2 cross section data is overestimated. The change in the amount of 148Nd due to both reactions is less than 0.7% under normal reactor operation conditions. In particular, it is in the 0.1% range if burnup is approximately 30 GWd/t for a BWR and 40 GWd/t for a PWR.

触媒充填層反応器におけるホットスポットを高精度かつ効率的に推定する手法の開発を行った．本手法は，可変グリッド法と拡張カルマンフィルタを組み合わせた手法である．一般的な均一グリッドによる推定手法とは異なり，可変グリッド法は状態量の分布に合わせて動的にグリッドを構成することができる．このため，可変グリッド法により偏微分方程式から高精度かつ少ない計算コストで解を得ることができる．触媒充填層反応器を対象としてシミュレーションにより本手法の有用性について検討したところ，均一グリッドを用いた拡張カルマンフィルタによる推定結果よりも良好に，なおかつ計算コストを増やすことなくホットスポットを推定することができた．

The burnup code system Step-Wise Burnup Analysis Code System (SWAT) is revised for use in a burnup credit analysis. An important feature of the revised SWAT is that its functions are achieved by ca...

To establish a nuclide composition benchmark data set for the verification of burnup codes, destructive analyses of light water reactor spent-fuel samples, which were cut out from several heights of spent-fuel rods, were carried out at the analytical laboratory at the Japan Atomic Energy Research Institute. The 16 samples from three kinds of pressurized water reactor (PWR) fuel rods and the 18 samples from two boiling water reactor (BWR) fuel rods were examined. Their initial 235U enrichments and burnups were from 2.6 to 4.1% and from 4 to 50 GWd/t, respectively. One PWR fuel rod and one BWR fuel rod contained gadolinia as a burnable poison. The measurements for more than 40 nuclides of uranium, transuranium, and fission product elements were performed by destructive analysis using mass spectrometry, and alpha-ray and gamma-ray spectrometry. Burnup for each sample was determined by the 148Nd method. The analytical methods and the results as well as the related irradiation condition data are compil...

Under an atmospheric pressure of hydrogen alkynes were successively hydrogenated to give alkanes via (Z)-alkenes with the metallic nickel catalyst, which was easily prepared by reaction of nickel bromide with zinc powder. Phosphines and diamines as catalyst modifiers were effective for the partial hydrogenation of alkynes.

The aim of this study is to develop a new technique for reducing high radon level in indoor air by method of membrane permeation using a hollow fiber module. The experiment has been carried out for MERASILOX-S module of fine hollow fibers of silicon rubber that has high permeability constant and MHF hollow fiber module made of thin segment polyurethane membrane. The radon permeability constants of hollow fiber membranes have been estimated from the decrease rate of radon concentration in a radon permeation system. The apparent permeability constant depends on the flow rate through the outside and the inside of hollow fibers. The apparent permeability constants of MERASILOX-S and MHF module membranes were 3.9×10 -9 m 2. s -1 and 1.1×10 -9 m 2. s -1 at the flow rate above 5.0 L . min -1 . However, the permeation velocity of MHF module is grater than that of MERASILOX-S module. The radon concentration in a 50 m 3 room of concrete building could be reduced to about 1/10 by using a MHF module with membrane area of 18 m 2 . The use of pressure different between the inside and the outside of hollow fibers might be applied to reduce the environmental radon concentration.