Background: Data on antimicrobial use at the national level is crucial to establish domestic antimicrobial stewardship policies and enable medical institutions to benchmark against each other. This study aimed to analyze antimicrobial use in Korean hospitals. Methods: We investigated the antimicrobials prescribed in Korean hospitals between 2018 and 2021, using data from the Health Insurance Review and Assessment. Primary care hospitals (PCHs), secondary care hospitals (SCHs), and tertiary care hospitals (TCHs) were included in this analysis. Antimicrobials were categorized according to the Korea National Antimicrobial Use Analysis System (KONAS) classification, which is suitable for measuring antimicrobial use in Korean hospitals. Results: Out of more than 1,900 hospitals, PCHs and TCHs represented the largest and lowest percentage of hospitals, respectively. The most frequently prescribed antimicrobial in 2021 was piperacillin/β-lactamase inhibitor (9.3%) in TCHs, ceftriaxone (11.0%) in SCHs, and cefazedone (18.9%) in PCHs. Between 2018 and 2021, the most used antimicrobial class according to the KONAS classification was ‘broad-spectrum antibacterial agents predominantly used for community-acquired infections’ in TCHs and SCHs, and 'narrow spectrum beta-lactam agents' in PCH. Total consumption of antimicrobials has decreased from 951.7 to 929.9 days of therapy (DOT)/1,000 patient-days in TCHs and from 817.8 to 752.2 DOT/1,000 patient-days in SCHs during study period, but not in PCHs (from 504.3 to 527.2 DOT/1,000 patient-days). Moreover, in 2021, while use of reserve antimicrobials has decreased from 13.6 to 10.7 DOT/1,000 patient-days in TCHs and from 4.6 to 3.3 DOT/1,000 patient-days in SCHs, it has increased from 0.7 to 0.8 DOT/1,000 patient-days in PCHs. Conclusion: This study confirms that antimicrobial use differs by hospital type in Korea. Recent increases of use of antimicrobials, including reserve antimicrobials, in PCHs reflect the challenges that must be addressed.

Climate change poses a major threat to marine ecosystems, with its effects felt worldwide. A major effect of climate change on marine ecosystems is the rise in water temperature, leading to a northward expansion of habitats for marine organisms. Herdmania momus, a species of ascidians (sea squirts), originally found in tropical and subtropical regions, was introduced to the Korean Peninsula. In this study, we examined the habitat of H. momus along the southeastern coast of the Korean Peninsula between 2016 and 2022. We found that H. momus settlements were observed across the entire survey area, with confirmed habitation in Busan in 2016, Ulsan in 2021, and Gyeongju (the northernmost location) in 2022. The observed habitation trend indicates a rapid geographical expansion, occurring approximately 79 years earlier than previously predicted. These observations demonstrate that marine organisms are undergoing a more rapid geographical expansion than previously projected. These unexpected findings should inform government policies related to proactive measures and strategies for managing the impact of climate change on marine ecosystems.

The immobilization of antimicrobial drugs can be used to expand the application of antibacterial properties to consumer products. The purpose of this study was to stabilize an antimicrobial agent, levofloxacin (LVX), for sustained antibacterial activity by immobilizing the drug molecules in a layered double hydroxide (LDH) and embedded in a polyurethane substrate. As-prepared MgAl-LDH was calcined at 400°C and reconstructed with LVX for intercalation. The X-ray diffraction patterns and cross-sectional transmission electron microscopy images showed lattice expansion along the crystallographic c axis upon LVX intercalation, suggesting successful loading of the drug. Fourier-transform infrared spectra revealed that the structure of LVX was well preserved between LDH layers. Elemental analysis indicated that the loading capacity of LVX in the hybrid was 41.7%. Bacterial-colony forming inhibitory assay on Bacillus subtilis exhibited ~100% antibacterial activity of both LVX alone and LVX-LDH hybrid (LL). To determine sustainability of antibacterial activity by the hybrid, either LVX alone or LL hybrid was loaded in the polyurethane (PU) substrate for which antibacterial activity was evaluated before and after immersion in a phosphate-buffered saline for 3 days. The LVX-composited PU showed a dramatic decrease in antibacterial activity, down to 0% after buffer treatment; LL-composited PU still contained antibacterial activity (~34% of colony suppression) after phosphate-buffered saline immersion.

Birds in flight are prone to collide with various transparent or reflective structures. While bird–window collision has been recognised as a critical conservation issue, collision with other transparent structures has been less understood. Noise barriers made of transparent materials are considered critical hazards for birds; however, little is known about the bird mortality they cause. We conducted the first nationwide-scale estimates of bird-collision mortality caused by transparent noise barriers (TNBs) along roads in the Republic of Korea. The total length of existing roadside transparent noise barriers was estimated at 1,416 km nationwide (as of 2018), and it had been increasing exponentially. Based on carcass surveys at 25 sites, daily mortality at the observed barriers was 0.335 ± 1.132 birds/km on average, and no difference in observed mortality was detected between both sides of a single barrier and between road types (i.e. local roads and motorways). Finally, we estimated that approximately 186,000 birds (95% confidence interval: 162,465–204,812 birds) are killed annually by collisions with roadside TNBs. As privately installed barriers were not considered in this study, the actual mortality is likely be higher than our estimates. Thus, collision with TNBs could become an emerging threat to avian conservation, especially in developing and urbanising regions around the world. As such structures are not formally recognised as conservation issues of importance, more systematic surveys aided by citizen science, both for the status of TNBs and bird-collision mortality, are needed in addition to management and mitigation policies.

OBJECTIVES/GOALS: In a familial case where 10 of 17 members inherited EA/LVNC in an autosomal dominant pattern, we discovered a novel, damaging missense variant in the gene KLHL26 that segregates with disease and comprises an altered electrostatic surface profile, likely decoupling the CUL3-interactome. We hypothesize that this KLHL26 variant is etiologic of EA/LVNC. METHODS/STUDY POPULATION: We differentiated a family trio (a heart-healthy daughter and EA/LVNC-affected mother and daughter) of induced pluripotent stem cells into cardiomyocytes (iPSC-CMs) in a blinded manner on three iPSC clones per subject. Using flow cytometry, immunofluorescence, and biomechanical, electrophysiological, and automated contraction methods, we investigated iPSC-CM differentiation efficiency between D10-20, contractility analysis and cell cycle regulation at D20, and sarcomere organization at D60. We further conducted differential analyses following label-free protein and RNA-Seq quantification at D20. Via CRISPR-Cas9 gene editing, we plan to characterize KLHL26 variant-specific iPSC-CM alterations and connect findings to discoveries from patient-specific studies. RESULTS/ANTICIPATED RESULTS: All iPSC lines differentiated into CMs with an increased percentage of cTnT+ cells in the affected daughter line. In comparison to the unaffected, affected iPSC-CMs had fewer contractions per minute and altered calcium transients, mainly a higher amount of total calcium release, faster rate of rise and faster rate of fall. The affected daughter line further had shorter shortening and relaxation times, higher proliferation, lower apoptosis, and a smaller cell surface area per cardiac nucleus. The affected mother line trended in a similar direction to the affected daughter line. There were no gross differences in sarcomere organization between the lines. We also discovered differential expression of candidate proteins such as kinase VRK1 and collagen COL5A1 from proteomic profiling. DISCUSSION/SIGNIFICANCE: These discoveries suggest that EA/LVNC characteristics or pathogenesis may result from decreased contractile ability, altered calcium transients, and cell cycle dysregulation. Through the KLHL26 variant correction and introduction in the daughter lines, we will build upon this understanding to inform exploration of critical clinical targets.

A number of microorganisms were hypothesised as an aetiology of the Kawasaki disease. Unfortunately, no specific agent that provides reproducible evidence has yet been reported. We report two cases of extremely rare Kawasaki disease with tsutsugamushi disease. These case reports suggest that Kawasaki disease can rarely occur concurrently or immediately after a rickettsial illness such as tsutsugamushi disease.

The Sewol ferry disaster is one of the most tragic events in Korea’s modern history. Among the 476 people on board, which included Danwon High School students (324) and teachers (14), 304 passengers died in the disaster (295 recovered corpses and 9 missing) and 172 survived. Of the rescued survivors, 72 were attending Danwon High School, located in Ansan City, and residing in a residence nearby. Because the students were young, emotionally susceptible adolescents, both the government and the parents requested the students be grouped together at a single hospital capable of appropriate psychiatric care. Korea University Ansan Hospital was the logical choice, as the only third-tier university-grade hospital with the necessary faculty and facilities within the residential area of the families of the students. We report the experiences and the lessons learned from the processes of preparing for and managing the surviving young students as a community-based hospital. (Disaster Med Public Health Preparedness. 2017;11:389–393)

A new method for determining the vitrification rate of pottery depending on the firing temperature was devised using secondary electron images (SEI) of scanning electron microscope (SEM). Several tests were performed to establish the appropriate operating conditions of SEM and reproducibility as well as to examine the applicability of the method. The grayscale values converted from each pixel of SEI were used to determine the vitrification rate of pottery, which in our study were artificially fired specimens composed of three types of clay. A comparison between the vitrification rate value and appearance temperature of minerals shows that mullite formation starts at 1,100°C, during which the vitrification rate rapidly increases by over 10%. In consequence, the result presented here demonstrates that the new method can be applied to estimate the firing temperature of pottery.

The technological development of all kinds of lightweight transportation devices including vehicles, aircraft, ships, etc. has progressed markedly with the demand for energy saving and environmental protection. Aluminum alloy is in the spotlight as it is a suitable environmentally friendly material. However, deformation is a major problem during the welding process because aluminum alloy has a large thermal expansion coefficient. In addition, it is known that its corrosion resistance is excellent; nevertheless, in practice, considerable corrosion is generated and this is a major problem. To solve this problem, the friction stir welding (FSW) technology is applied extensively at various industrial fields as a new welding technique. This method involves a process in which materials are joined by frictional heat and physical force. Therefore, we evaluated improvements in mechanical properties and corrosion resistance through annealing heat treatment after FSW. The electrochemical experiment did not show a significant difference. However, the microstructure observation showed defectless, fine crystal particles, indicating excellent properties at 200–225°C.

The microstructural analysis of the dehydrogenation products of the Ca(BH4)2–MgH2 composite was performed using transmission electron microscopy. It was found that nanocrystalline CaB6 crystallites formed as a dehydrogenation product throughout the areas where the signals of Ca and Mg were simultaneously detected, in addition to relatively coarse Mg crystallites. The uniform distribution of the nanocrystalline CaB6 crystallites appears to play a key role in the rehydrogenation of the dehydrogenation products, which implies that microstructure is a crucial factor determining the reversibility of reactive hydride composites.

Metal oxide nanoparticles within the protein ferritin can act as an energy storage source in nano-bio batteries containing ferrous ferritin and a reconstituted ferritin cage containing different inorganic elements, such as Co, Mn, Ni, and Pt. These components were introduced as two ferritin half-cells with different redox potentials existing between the ferrous ferritin and the reconstituted ferritin. The reduction of ferritin was analyzed in a solution containing 3-[N-morpholino] propanesulfonic acid buffer and oxidized methyl viologen using cyclic voltammetry. The reduction and oxidation peaks of the methyl viologen occurred at potentials of −300 and −100 mV, respectively, and the reduction and the oxidation peaks of the released Fe occurred at potentials of −300 and −100 mV, respectively. The reduction of ferritin was influenced by the pH of the ferritin solution.

The swelling behavior of chitosan hydrogels in ionic liquid–water binary systems was studied using hydrophilic room-temperature ionic liquids (RTILs) to elucidate the swelling properties of chitosan hydrogels. It was confirmed that chitosan hydrogels are much stiffer after immersing in a pure RTIL because the water existing inside the chitosan polymer network is extracted into the RTIL. The pH of the binary system changes when the RTIL is in contact with water. The chitosan hydrogels were fully dissociated at a 90% water content in the BMI-BF4-water binary system. The equilibrium binary system content behavior of the chitosan hydrogels depended upon the amount of free water present. The water behavior in a pure RTIL was examined using differential scanning calorimetry.

Composite fibers composed of chitosan and single-wall carbon nanotubes (CNTs) have been fabricated using a wet spinning method. The dispersion was improved by the sonic agitation of the CNTs in a chitosan solution followed by centrifugation to remove tube aggregates and any residual catalyst. The mechanical behavior was investigated using a dynamic mechanical analyzer (DMA). The mechanical tests showed a dramatic increase in Young's modulus for the chitosan/CNT composite fibers fabricated using the improved dispersion method. The strain on the microfibers was determined from tensile load measurements during pH switching in acidic or basic electrolyte solutions. The microfibers showed a general actuation behavior of expanding at pH = 2 and contracting at pH = 7 under low tensile loads. However, a reverse of this actuation behavior was exhibited under high tensile loads. This anomalous pH actuation is both new and surprising. It was explained from an analysis of the differences in sample stiffness and Poisson’s ratio under tensile load in electrolyte solutions with different pH values.