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The mechanical consequences of core disruptive accidents (CDAs) are a major safety concern in sodium-cooled fast reactors. Once core disruption occurs, liquefied core materials rapidly disperse vertically and radially. The dispersed materials penetrate the pin bundles and control rod guide tubes (CRGTs) before freezing at the edge of the penetration zone as heat is transferred to surrounding structures. Such freezing phenomena can suppress the negative reactivity feedback of fuel dispersion. The discharge of core materials can be impeded, resulting in a molten core pool formation when tight blockages occur inside CRGTs due to frozen material. Accordingly, freezing phenomena of core materials play a key role in governing the mechanical consequences of a CDA. To validate a freezing model implemented in our CDA analysis code, ASTERIA-SFR, a preliminary simulation of the THEFIS RUN#1 test, was performed. The calculation results show that freezing on the structural wall and crust formation were key phenomena affecting the penetration behavior, and the structural heat transfer is an important parameter. A remarkable reduction of the heat transfer coefficient was required to reproduce the penetration length observed in the experiment. This suggests that the momentum exchange and flow regime at the leading edge as well as heat transfer should be well modeled to predict the freezing phenomena in rapidly evolving CDAs. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate prolonged esomeprazole use in Japanese pediatric patients for reflux esophagitis (RE) maintenance therapy and prevention of gastric (GU) and/or duodenal ulcers (DU) while using non-steroidal anti-inflammatory drugs (NSAIDs) or low-dose aspirin (LDA). Methods: This multicenter, open-label, parallel-group, phase III study (NCT03553563) included patients who were administered esomeprazole according to body weight (10 mg/day [Groups 1 and 3] and up to 20 mg/day [Groups 2 and 4] for patients weighing 10-20 kg and ≥20 kg, respectively). Efficacy outcomes for Groups 1 and 2 (maintenance therapy for healed RE) and Groups 3 and 4 (prevention of long-term NSAID/LDA use-associated GU/DU) were the presence/absence of RE relapse and GU/DU recurrence, respectively. Results: Esomeprazole as maintenance therapy was associated with a low RE recurrence rate, independent of body weight or dosage. Recurrence rates of RE were 0.0% and 5.3% for Groups 1 and 2, respectively. In patients previously diagnosed with GU and/or DU due to long-term NSAID/LDA use, the recurrence rates of GU/DU during weeks 0-32 were 11.1% and 0.0% in Groups 3 and 4, respectively. Conclusion: Long-term use of 10- or 20-mg, once-daily esomeprazole demonstrated a favorable benefit-risk balance in preventing RE and suppressing recurrence of GU and/or DU secondary to NSAID or LDA therapy in Japanese pediatric patients. No new safety concerns were identified. Esomeprazole may be a viable option for managing RE and preventing GU and DU in Japanese pediatric patients. [ABSTRACT FROM AUTHOR]

Background: Xanthine oxidase inhibitors are anti-hyperuricemic drugs that decrease serum uric acid levels by inhibiting its synthesis. Xanthine oxidase is also recognized as a pivotal enzyme in the production of oxidative stress. Excess oxidative stress induces endothelial dysfunction and inflammatory reactions in vascular systems, leading to atherosclerosis. Many experimental studies have suggested that xanthine oxidase inhibitors have anti-atherosclerotic effects by decreasing in vitro and in vivo oxidative stress. However, there is only limited evidence on the clinical implications of xanthine oxidase inhibitors on atherosclerotic cardiovascular disease in patients with hyperuricemia. We designed the PRIZE study to evaluate the effects of febuxostat on a surrogate marker of cardiovascular disease risk, ultrasonography-based intima-media thickness of the carotid artery in patients with hyperuricemia. Methods: The study is a multicenter, prospective, randomized, open-label and blinded-endpoint evaluation (PROBE) design. A total of 500 patients with asymptomatic hyperuricemia (uric acid >7.0 mg/dL) and carotid intima-media thickness ≥1.1 mm will be randomized centrally to receive either febuxostat (10-60 mg/day) or non-pharmacological treatment. Randomization is carried out using the dynamic allocation method stratified according to age (<65, ≥65 year), gender, presence or absence of diabetes mellitus, serum uric acid (<8.0, ≥8.0 mg/dL), and carotid intimamedia thickness (<1.3, ≥1.3 mm). In addition to administering the study drug, we will also direct lifestyle modification in all participants, including advice on control of body weight, sleep, exercise and healthy diet. Carotid intima-media thickness will be evaluated using ultrasonography performed by skilled technicians at a central laboratory. Follow-up will be continued for 24 months. The primary endpoint is percentage change in mean intima-media thickness of the common carotid artery 24 months after baseline, measured by carotid ultrasound imaging. Conclusions: PRIZE will be the first study to provide important data on the effects of febuxostat on atherosclerosis in patients with asymptomatic hyperuricemia. [ABSTRACT FROM AUTHOR]