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The natural circulation phenomena occurring in fully integrated nuclear reactors are associated with a unique formation mechanism. The phenomenon results from a structural feature of these reactors involving upward flow from the core, located in the central-bottom region of a single vessel, and downward flow to the steam generator in the annulus region. In this study, to understand the natural circulation in a single vessel involving a multi-layered flow path, single-phase and two-phase natural circulation tests were performed using the SMART-ITL facility, and validation analysis of the TASS/SMR-S code was performed by comparing the corresponding test results. Three single-phase natural circulation tests were sequentially conducted at 15%, 10%, and 5% of full-scaled core-power without RCP operation, following which a two-phase natural circulation test was successively conducted with an artificial discharge of coolant inventory. The simulation capability of the TASS/SMR-S code with respect to the natural circulation phenomena was validated against the test results, and somewhat conservative but reasonably comparative results in terms of overall thermalhydraulic behavior were shown.

System-integrated modular advanced reactor (SMART) is a small-sized advanced integral type pressurized water reactor (PWR) with a rated thermal power of 330 MW. It can produce 100 MW of electricity or 90 MW of electricity and 40,000 ton of desalinated water concurrently, which is sufficient for 100,000 residents. The design features contributing to safety enhancement are basically inherent safety improvement and passive safety features. TASS/SMR code was developed for an analysis of design based events and accidents in an integral type reactor reflecting the characteristics of the SMART design. The main purpose of the code is to analyze all relevant phenomena and processes. The code should be validated using experimental data in order to confirm prediction capability. TASS/SMR predicts well the overall thermal-hydraulic behavior under various natural circulation conditions at the experimental test facility for an integral reactor. A pressure loss should be provided a function of Reynolds number at low velocity conditions in order to simulate the mass flow rate well under natural circulations.

Abstract Background In this study, we observe the patterns initial palliative treatment for premenopausal patients with HR-positive/HER2-negative MBC and determine if nonadherence to clinical guidelines are associated with worse clinical outcomes in terms of progression-free survival (PFS) and overall survival (OS) in the South Korean population. Methods A retrospective review was performed for premenopausal patients diagnosed with HR-positive/HER2-negative MBC between October 1997 and May 2016 who received palliative systemic treatments at a large tertiary medical center. Survival outcomes were analyzed according to the palliative treatment received prior to disease progression. Results The review identified a total of 272 premenopausal patients meeting study criteria, whose median age was 39 years. Endocrine therapy was the initial treatment in 137 patients (Group 1) with chemotherapy as initial treatment in 135 patients. In the latter group, chemotherapy was continued in 78 patients (Group 2), whereas chemotherapy was switched to endocrine treatment in 57 patients prior to any disease progression (Group 3). Both PFS and OS were significantly longer for chemotherapy-endocrine therapy (median PFS 18.2 months and OS 85.2 months) than for chemotherapy-alone (median PFS 12.6 months and OS 45.5 months) or endocrine therapy-alone (median PFS 7.0 months and OS 57.3 months) (all p values

Despite limitations in payload and range, cargo drones have promising applications in emergency logistics and remote delivery. In this study, we tackle these challenges by developing a high-capacity 3.84 kW battery specifically designed for a 50-kg-payload cargo drone operating in demanding terrains. Focusing on the transport of emergency goods, we investigate key drone design aspects and details of the battery pack development, including cell selection, internal configuration, and critical circuits for cell balancing, charging/discharging, and advanced battery management. A key innovation is the integration of a backpropagation artificial neural network (BPANN) algorithm to predict the depth of discharge (DoD) and the state of charge (SoC). Research results show that BPANN offers highly accurate predictions, with error percentages as low as 0.12% for DoD and 0.02% for SoC, ensuring optimized and safe battery operation. Comprehensive field testing is carried out to evaluate the effectiveness of the proposed cell balancing strategy, robust battery management system (BMS), and BPANN implementation. We investigate the drone's performance in terms of DoD, SoC, and overall field operation with the designed battery pack and demonstrate its feasibility and potential for realworld applications. [ABSTRACT FROM AUTHOR]

Myeloid sarcoma (MS) is an extramedullary involvement of immature myeloid proliferation. An isolated MS is defined as a myeloblastic tumor when it arises without any concomitant circulating disease. A diagnosis of MS is established using pathologic features including infiltration of myeloblasts and strong myeloperoxidase expression with negative cytokeratin immunohistochemical staining. We report a rare case of colonic MS without any peripheral blood abnormality. If the affected patient were left untreated, the MS could evolve into acute myeloid leukemia (AML) within one year. Several studies recommend the same regimens of chemotherapy as used for circulating AML to treat isolated MS. We focused on the diagnosis of MS in this study. The correct diagnosis of MS is important for adequate treatment. In conclusion, MS should be considered in the differential diagnosis of intestinal tumor. (Korean J Gastroenterol 2016;68:148-151)

Purpose Epidermal growth factor receptor (EGFR) exon 20 insertion mutations account for approximately 4% of all EGFRmutations. Given the rarity of this mutation, its clinical outcomes are not fully established. Materials and Methods Between 2009 and 2017, non-small cell lung cancer (NSCLC) patients who showed an exon 20 insertion were retrospectively reviewed for clinical characteristics and outcomes, including responses to chemotherapy (CTx) or targeted therapy. Results Of 3,539 NSCLC patients who harbored an activating EGFR mutation, 56 (1.6%) had an exon 20 insertion. Of the advanced NSCLC patients, 27 of 1,479 (1.8%) had an exon 20 insertion. The median overall survival was 29.4 months (95% confidence interval 9.3 to 49.6) for 27 advanced NSCLC patients. The 22 patients who received systemic CTx achieved a 50.0% response rate and a 77.2% disease control rate, with 4.2 months of progressionfree survival. Six patients received EGFR tyrosine kinase inhibitors (TKIs). Three of the four patients that had only an exon 20 insertion showed progressive disease, while one showed stable disease. The other two patients had an exon 20 insertion and another EGFRmutation and achieved a partial response. Conclusion The incidence of an exon 20 insertion mutation is rare in Korea and occasionally accompanied by other common EGFR mutations. Although the response to systemic CTx. in these patients is comparable to that of patients with other mutations, the response rate to firstor second-generation EGFR TKIs is quite low. Therefore, the development of a more efficient agent is urgently needed. [ABSTRACT FROM AUTHOR]

Purpose This study was conducted to evaluate the relationship between epidermal growth factor receptor (EGFR) mutation and clinical outcomes in patients with stage III non-squamous cell lung cancer treated with definitive concurrent chemoradiotherapy (CCRT). Materials and Methods From January 2008 to December 2013, the medical records of 197 patients with stage III non- squamous non-small cell lung cancer treated with definitive CCRT were analyzed to determine progression-free survival (PFS) and overall survival (OS) according to EGFR mutation status. Results Among 197 eligible patients, 81 patients were EGFR wild type, 36 patients had an EGFR mutation (exon 19 Del, n=18; L858R, n=9, uncommon [G719X, L868, T790M], n=9), and 80 patients had unknown EGFR status. The median age was 59 years (range, 28 to 80 years) and 136 patients (69.0%) were male. The median follow-up duration was 66.5 months (range, 1.9 to 114.5 months). One hundred sixty-four patients (83.2%) experienced disease progression. Median PFS was 8.9 months for the EGFR mutation group, 11.8 months for EGFR wild type, and 10.5 months for the unknown EGFR group (p=0.013 and p=0.042, respectively). The most common site of metastasis in the EGFR mutant group was the brain. However, there was no significant difference in OS among the three groups (34.6 months for EGFRmutant group vs. 31.9 months for EGFR wild type vs. 22.6 months for EGFR unknown group; p=0.792 and p=0.284). A total of 29 patients (80.6%) with EGFR mutation were treated with EGFR tyrosine kinase inhibitor (gefitinib, n=24; erlotinib, n=3; afatinib, n=2) upon progression. Conclusion EGFRmutation is associated with short PFS and the brain is the most common site of distant metastasis in patients with stage III non- squamous cell lung cancer treated with CCRT. [ABSTRACT FROM AUTHOR]

Lung cancer remains a leading cause of cancer mortality worldwide, including in Korea. Systemic therapy including platinum-based chemotherapy and targeted therapy should be provided to patients with stage IV non-small cell lung cancer (NSCLC). Applications of targeted therapy, such as an epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) and anaplastic lymphoma kinase (ALK) inhibitors, in patients with NSCLC and an EGFR mutation or ALK gene rearrangement has enabled dramatic improvements in efficacy and tolerability. Despite advances in research and a better understanding of the molecular pathways of NSCLC, few effective therapeutic options are available for most patients with NSCLC without druggable targets, especially for patients with squamous cell NSCLC. Immune checkpoint inhibitors such as anti-cytotoxic T lymphocyte antigen-4 or anti-programmed death-1 (PD-1) or programmed death-ligand 1 (PD-L1) have demonstrated durable response rates across a broad range of solid tumors, including NSCLC, which has revolutionized the treatment of solid tumors. Here, we review the current status and future approaches of immune checkpoint inhibitors that are being investigated for NSCLC with a focus on pembrolizumab, nivolumab, atezolizumab, durvalumab, and ipilimumab.