In Korea, Nuclear Power Plants continually prepare and revise the final safety analysis report (FSAR), which is essential for predicting the source-term information of radioactive materials throughout their lifecycle. This report provides detailed information on the source-terms of Chalk River Unidentified Deposits (CRUD). The management of radioactive corrosion products, present on nuclear fuel surfaces and within the primary system, is crucial for ensuring equipment integrity and controlling worker exposure during operation. Unlike earlier studies that focused solely on the radioactive inventory of major components, this study established an integrated evaluation framework by coupling the CRUDTRAN, ORIGEN2, and PHITS codes to quantitatively assess the relative contribution of the CRUD source-term on the core support barrel (CSB) to worker doses, in comparison with the activation source-terms of the reactor pressure vessel (RPV). By calculating these specific source-terms and conducting subsequent radiation exposure assessments, this work underscores the critical significance of the CRUD source-term during the decommissioning phase. The comparative dose assessment revealed that in the absence of system decontamination, the radiation exposure contributed by the CRUD source-term exceeded that from the structural activation of the RPV across the range of deposition-fraction assumptions, from about 1.5 times under the minimum assumption to about 117 times under the maximum assumption. These quantitative findings indicate that CRUD is a major source of worker exposure during the decommissioning phase, which should not be neglected relative to the activation of internal components.
While transformational and transactional leadership are key drivers of performance in public organizations, their effects on organizational effectiveness depend on structural conditions. This study examines organizational effectiveness-measured as agencies' reported goal attainment-and analyzes how the span of control, an indicator of the structural distance between leaders and subordinates, moderates the relationship between these leadership styles and effectiveness. Drawing on panel data from U.S. federal agencies, the analysis shows that transformational leadership is positively associated with effectiveness, whereas transactional leadership is negatively associated with it. Moreover, transformational leadership relates more strongly to effectiveness under narrow spans of control, where supervisors provide more personalized attention, whereas transactional leadership is more effective under broader spans that rely on standardized oversight. These findings clarify how leadership approaches can align with organizational structures to enhance public sector effectiveness.
AB5 toxins constitute a major family of bacterial exotoxins. Their pathogenicity depends on the coordinated actions of two components: an enzymatically active A subunit and a pentameric B subunit. The B subunit mediates host cell recognition and intracellular trafficking. Among them, cholera toxin represents a representative model for investigating structure–function relationships governing toxin entry and delivery. While the catalytic activity of the A subunit has been extensively characterized, growing evidence indicates that pathogenic outcomes are critically shaped by trafficking strategies encoded within the B subunit pentamer. This review focuses on the cholera toxin B subunit (CTB) as a model system to elucidate how pentameric organization enables multivalent GM1 recognition, receptor clustering, and efficient intracellular transport. We summarize current knowledge on the molecular basis of CTB pentamerization, its thermodynamic and structural advantages, and the role of multivalency in amplifying delivery efficiency and pathogenicity. In addition, we examine how CTB-mediated intracellular trafficking influences uptake pathway selection and intracellular routing, thereby contributing to consistent and robust toxic outcomes. Beyond pathogenic mechanisms, we briefly discuss the potential implications of CTB-mediated trafficking for translational applications. By integrating structural, cellular, and functional perspectives, this review demonstrates how CTB-mediated mobility governs intracellular routing and uptake pathway selection. This framework provides a basis for understanding AB5 toxin pathogenicity and its broader biological significance.
This study optimized the design and operating parameters of proton exchange membrane water electrolyzers (PEMWEs) by using a computational approach. Initially, sensitivity analysis was used to identify optimal parameters, with liquid water saturation, hydrogen production rate, and ohmic resistance selected as performance indicators. Five parameters were then scanned parametrically to generate a large dataset for artificial neural network (ANN) training. Subsequently, the non-dominated sorting genetic algorithm with elite strategy (NSGA2) was employed to simultaneously optimize the three performance indicators, achieving values of 0.7839, 114.25 mΩ, and 3767.6 mol·s−1·m−3, respectively. The optimized design exhibited a lower polarization curve than the original model, indicating reduced power consumption during electrolysis. The increased liquid water saturation enhances water transport and electrolysis efficiency; reduced ohmic resistance minimizes energy loss; and the higher hydrogen production rate supports improved fuel cell operation.
All solid-state batteries (ASSBs) employing sulfide-based electrolytes have attracted great attention as emerging energy storage systems due to high safety, high energy density, broad operating temperatures, etc. However, the introduction of sulfide-based solid electrolytes causes interfacial side-reactions with cathode/anode materials, resulting in electrochemical degradation. Here, we report a new intercalation-type Cu1.8S cathode material with a high capacity and interfacial compatibility for ASSBs. Compared to metal sulfides (MxS), copper sulfides only have metal-rich phases (x >= 1.6) due to the unique oxidation state of +1, enabling no weak S-S bonds, all strong Cu-S bonds, and a structural rigidness upon intercalation of foreign atoms. As a starting material, spherical microparticles assembled from CuS nanocrystals are prepared by a solvothermal method. After calcination at 300 degrees C, the CuS granules are transformed to porous Cu1.8S microspheres with a particle size of 1-3 & micro;m and a surface area of 1.4 m2 g-1. A Cu1.8S-based cathode shows a charge/discharge capacity of 274 mAh g-1, a capacity retention of 80% over 100 cycles, and a high-rate capability of similar to 190 mAh g-1 at 1C-rate in a potential window of 0.5-2.5 V vs. Li/Li+, leading to 1.5 times higher energy density than that of the conventional LiCoO2 cathode. In addition, it shows a suppressed side reaction and electrochemical compatibility with the sulfide-based electrolyte. The achievements open a new avenue for the potential use of copper sulfides as cathode materials for ASSBs.
