Korea Institute Research Articles

A Multicenter Study on Hepatocellular Adenomas in Korea: Clinicopathological and Imaging Features With an Emphasis on β-Catenin Mutated Subtype.

The clinicopathologic and imaging features of hepatocellular adenomas (HCAs) in Asian population remain unclear. We aimed to analyse clinicopathologic and imaging features of HCAs in Korea and propose an imaging-based method to differentiate β-catenin mutated HCA (βHCA) from other subtypes. This retrospective multicenter study included pathologically confirmed HCAs from three tertiary institutions in Korea between 2010 and 2023. HCA subtypes were determined according to the current World Health Organization classification using immunohistochemical staining. Two abdominal radiologists reviewed computed tomography and magnetic resonance imaging scans. The clinical characteristics and imaging features of HCA subtypes were compared. A scoring system for βHCA was developed and validated using development (January 2010-April 2021) and validation (May 2021-March 2023) cohorts. 121 patients (47 men; mean age, 39.0 years ±13.5) with 138 HCAs were included. HCAs displayed characteristic clinicopathologic features, including a high proportion of male (38.8%) and obese patients (35.5%), with the inflammatory subtype being the most common (38.4%) and a low percentage of patients using oral contraceptive (5.0%). Each HCA subtype demonstrated distinct clinical and imaging features. The scoring system incorporating tumour heterogeneity and iso to high hepatobiliary phase signal intensity on MRI for differentiating βHCA exhibited high performance in both the development (AUC 0.92, 95% CI: 0.87-0.97) and the validation cohort (AUC 0.91, 95% CI: 0.77-1.00). This comprehensive analysis of clinicopathologic and imaging features of HCAs in Korea contributes to the characterisation of HCAs across different geographical regions. The imaging-based scoring system effectively differentiates βHCA.

Skin Rash in metastatic Hormone Sensitive Prostate Cancer Patients Treated with Apalutamide: A Retrospective Multicenter Study in Korea

PurposeSkin rash is a common adverse event in patients with metastatic hormone-sensitive prostate cancer (mHSPC) treated with apalutamide. This study aims to investigate the incidence rate of skin rash and the predictive value of inflammation markers for skin rash in real-world Korean patients. Materials and MethodsWe conducted a retrospective analysis of patients with prostate cancer (PCa) who received apalutamide across 18 institutions in Korea, with a follow-up period of at least three months. A total of 218 patients were evaluated. ResultsAmong the 214 patients analyzed, 78 (36.4%) developed a skin rash. The severity of the rash was classified as grade 1 (G1) in 27 patients (12.6%), grade 2 (G2) in 29 patients (13.5%), and grade 3 (G3) in 22 patients (10.3%). The median time to onset of any skin rash was 65.5 days (interquartile range, IQR 31.0-88.0). There were no significant differences in inflammation markers before apalutamide administration between patients who developed a rash and those who did not. However, the Monocyte-to-Lymphocyte Ratio (MLR) and Systemic Immune-Inflammation Response Index (SIRI) were significantly higher in the G2 plus G3 group compared to the no rash plus G1 group (p=0.006, p=0.013, respectively) before apalutamide treatment. After 3 months, Platelet-to-Lymphocyte Ratio (PLR) and SIRI were significantly higher in the G2 plus G3 group compared to the no rash plus G1 group (p=0.010, p=0.025, respectively) ConclusionIn a real-world cohort of Korean patients, skin rash occurred in 36.4% of cases, with a median time to onset of 65.5 days. Grade 3 skin rash developed in 10.3% of cases. While MLR and SIRI were significantly higher in the G2 plus G3 group, these markers cannot be considered reliable predictors due to a low area under the curve (AUC < 0.7) before apalutamide treatment. However, increased levels of PLR, SII, and SIRI could potentially be useful for monitoring for the risk of severe rash development in these patients.

국어과 중등교사 임용시험(2002-2024) ‘고전 시가’ 영역의 분석 및 방향

Objectives The purpose of this study was to analyze the questions in the ‘classical poetry’ area in the Korean Language Department Secondary Teacher Appointment Test (2002-2024), and to suggest what direction to proceed in the future. Methods Questions in the classical poetry area were extracted from the Korean language department secondary teacher appointment test questionnaire and analyzed ‘tendency’ and ‘type of question’ based on the direction and principles of questions provided by the Korea Institute for Curriculum and Evaluation. Results The tendency of the questions could be divided into three main categories. First, there was a great tendency to consist of 2-3 passages only within the classical poem. Second, there was a bias in the classical poem section that is presented every year. Third, there were many cases where the works that were presented reappeared in different forms with similar content. The types of questions were analyzed by dividing them by period. First, in the 2000s, there was a great tendency to write questions by memorizing knowledge or content about the work. Second, questions before and after 2010 were presented focusing on knowledge of literary history and understanding and analysis of works. Third, the written questions from 2014 to the present are presented to allow objective evaluation as much as possible, and the narrative questions are presented in the direction of analysis, reasoning, synthesis, and evaluation based on data. Conclusions Based on the analysis results, four directions for the future classical poetry appointment test are proposed. First, it is necessary to expand the scope of complex passages in classical poetry. Second, reduce the deviation of the frequently asked branches, and evenly present the branches of oral literature, Korean literature, and Chinese literature. Third, develop questions to measure more diverse and higher-order thinking. Fourth, the questions are presented so that the essence of the classic poem, “a poem” and “a song (歌)” can be confirmed or realized.

A Bibliometric Analysis of Research Trends in Hazard Mitigation Studies in Korea: Based on Articles from the Journal of Korean Society of Hazard Mitigation

This study conducts a bibliometric analysis to identify research trends in hazard mitigation, based on 3,074 papers published in the Journal of the Korean Society of Hazard Mitigation between 2010 and 2023. The findings revealed that research on climate change and disaster response was the most active, with key topics including natural disaster management, urban water resource management, fire analysis and prevention, and AI-based disaster management. A keyword analysis highlighted “disaster” and “climate change” as having the highest frequency and centrality within the network. Institutional analysis identified the Korea Institute of Civil Engineering and Building Technology as the leading institution in co-authorship, with high research productivity and a key role as an intermediary. The authors’ analysis revealed that certain authors were central to expanding the field through diverse cooperation. These insights highlight the evolution of hazard mitigation research in Korea and offer guidance for future research to tackle emerging challenges in disaster management.

National Health Insurance Claim of Pediatric Appendectomy With Mandatory Diagnosis-Related Group Payment System in Korea

IntroductionEnforcement of diagnosis-related group system for appendectomy under the National Health Insurance Service has gradually widened and since July 2013 it has been enforced in all medical institutions in Korea. We have analyzed Health Insurance Review & Assessment Service data to observe changes in claim patterns of pediatric appendectomy during this period. MethodsAll claims data for appendectomy of patients younger than 18 y from 2011 to 2015 were collected. We analyzed the following factors of all cases: age, gender, length of hospital stay, medical cost, method of insurance claim and region. ResultsA total of 112,143 claims were made for appendectomy during the study period. In that, 66,510 (59.3%) were boys and 45,633 (40.7%) were girls. Median length of stay was 5 d and median sum of reimbursement of each claim was 2,198,630 won. Annual number of claims for appendectomy showed a steady decline from 24,888 in 2011 to 19,070 in 2015. Median sum of reimbursement of each claim was 1,862,615, 1,975,500, 2,233,360, 2,376,700, and 2,468,000 won, respectively from 2011 to 2015. Reimbursement for complicated appendectomy increased from 4400 out of 24,888 cases (17.7%) in 2011 to 3865 out of 19,070 cases (20.3%) in 2015. Overall medical cost of all reimbursement for pediatric appendectomy increased from 46,113,202,580 to 47,572,253,300 won. ConclusionsFollowing the universal enforcement of the diagnosis-related group claim system for appendectomy by the National Health Insurance Service, we observed an increase in the median sum of reimbursement per claim and a rise in the rate of claims for complicated appendectomies. These changes were associated with an overall increase in national medical costs.

Preoperative Factors Affecting Graft Survival After ABO-incompatible Adult Liver Transplantation.

Although ABO-incompatible liver transplantation (ABOi LT) has undergone remarkable progress, the prognostic factors are poorly understood. This study aimed to elucidate the preoperative factors affecting graft survival after ABOi LT. Patients who underwent ABOi LT between January 2012 and December 2020 at a single institution in South Korea were retrospectively reviewed. A total of 146 recipients, including 34 patients with graft loss, were analyzed. In the multivariate Cox proportional hazard model, recipient age (≥55 y; hazard ratio, 2.47; 95% confidence interval, 1.18-5.19; P = 0.017) and donor ABO type (donor A, hazard ratio, 3.12; 95% confidence interval, 1.33-7.33; P = 0.009) were significantly associated with an increased risk of graft loss. The most common cause of graft loss was recipient death due to bacterial infection (15/34, 44.1%). Both recipient age and donor ABO type were associated with an increased risk of recipient death due to bacterial infections. The incidence of complications after ABOi LT, including antibody-mediated rejection and diffuse intrahepatic biliary stricture, did not differ according to recipient age or donor ABO type. These findings suggest that recipient age and donor ABO type should be considered when preparing for ABOi LT. Careful monitoring and care after transplantation are required for recipients with preoperative risk factors.

Comparison of the standardized incidence ratio of tuberculosis among workers at medical and educational institutions: a nationwide LTBI observational cohort study

BackgroundThe objective of this study was to determine the incidence of tuberculosis (TB) among workers at medical institutions based on interferon-gamma release assay (IGRA) and compare it with that of workers at educational institutions and the general population. MethodsFrom March 2017 to December 2020, we used a cohort of workers from medical and educational institutions in Korea, who underwent IGRA as part of a national screening program for latent tuberculosis infection (LTBI). After connecting to the National Health Insurance Service (NHIS) database to detect for any actual cases of active TB, we estimated standardized incidence ratio (SIR) and the expected number of cases to compare the incidence of TB with that of the general population. ResultsSignificant disparities in TB incidence were revealed among workers in medical and educational institutions, based on IGRA results, age, and occupation. Individuals positive for IGRA in medical institutions displayed substantially higher SIR for TB, 7.19 (6.15–8.41), compared to counterparts in educational institutions, 3.69 (3.02–4.51). Comparing by age group, we see that the SIRs are higher in younger age groups compared to older ones, with 37.30 (28.11–49.50) and 11.89 (7.28–19.41) for IGRA-positive medical and education workers under 30 years of age, respectively. In the results by occupation within the medical institutions, nurses had the highest SIR at 14.17 (11.14–18.04). ConclusionsHealthcare workers in medical institutions are more likely to develop actual TB after a positive result of LTBI screening in Korea. Intensive management and surveillance programs should be reinforced.

Revisiting Compassion and Job Performance: A Constructive Study in South Korean Public Art Institutions.

This study empirically examines how employee compassion relates to job performance. Specifically, this study is a constructive replication and expansion of a previous study on the relationship between compassion and job performance using multiple sources of measurement. It investigates unexplored pathways within the public art sector in South Korea. Focusing on the mediating roles of positive work-related identity (PWRI) and positive psychological capital, we collected data from public art institutions in Korea, including galleries and museums, using a survey method. We tested the hypotheses using structural equation modeling and the PROCESS bootstrapping method. Our findings demonstrate a positive association between compassion and job performance, serially mediated by PWRI and positive psychological capital. Theoretically, by constructively replicating and expanding the previous findings, our study contributes to a robust understanding of how compassion could enhance employee performance. Practically, this study reinforces the value of fostering compassion and positive psychological resources to improve job performance, particularly within the public art sector.

Activity Concentration of Natural Radionuclides in Surface Sediments of Major River Watersheds in Korea and Assessment of Radiological Hazards

The assessment of potential radiation hazards in accumulated sediments in aquatic ecosystems is vital for the management and disposal of sediments. Furthermore, preemptive management of radionuclides in terrestrial ecosystems is critical for marine ecosystem conservation. We analyzed the activity concentrations of natural radionuclides (226Ra,232Th, 238U, and 40K) in the surface sediments of major river watersheds in Korea and evaluated the radiation hazards stemming from these activity concentrations. The mean activity concentrations of 226Ra and 238U were lower than the global average, whereas those of 232Th and 40K were higher. The mean values of radium equivalent activity, external hazard index, and internal hazard index calculated from these activity concentrations did not exceed the recommended maximum values. The mean values of absorbed gamma dose rate in air and annual outdoor effective dose rate (AEDRout) were higher than the global average by the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) but remarkably lower than the recommended and background values by the International Commission on Radiological Protection (ICRP) and the Korea Institute of Nuclear Safety (KINS). The contribution of 40K and 232Th to the AEDRout mean value was predominant. In conclusion, the surface sediments of major river watersheds in Korea are associated with negligible radiation hazards. These findings provide fundamental data for the management and treatment of sediments in terrestrial and marine ecosystems.

B-053 Four years summary of flow cytometry live cell based assay for detecting serum anti-aquaporin 4 IgG and anti-myelin oligodendrocyte glycoprotein IgG in a Korean reference laboratory

Abstract Background In the diagnosis of neuromyelitis optica spectrum disorder (NMOSD), it is important to sensitively detect anti-aquaporin 4 (AQP4) IgG and anti-myelin oligodenrocyte glycoprotein (MOG) IgG in patients' serum. NMOSD is a disease that shows 3-7 times more common prevalence in Far East Asia than in the West. According to the IPND diagnostic criteria, it is recommended to diagnose as a cell based assay using full length recombinant protein. In this study, we would like to review 4 years results of AQP4, MOG requested to Eone laboratories in Korea performed with flow cytometry live cell based assay (FC-CBA). Methods FC-CBA was performed using piRES2 cell transfected with AQP4, MOG and stained with DsRed2. Subcultured cells were counted with 10^6, and reacted with patients' serum for 1 hour in a refrigerated state. Thereafter, reaction with FITC anti-human IgG for 2nd antibody for 30 minutes, and 10,000 cells were read from Navius (Beckman Coulter). The mean fluorescence intensity (MFI) ratio , which is the ratio obtained by dividing the MFI value of both FITC and DsRed2 positive cells and DsRed2 positive cells to negative cells, was used to determine positive, borderline, and negative for the serum sample. AQP4 reviewed cases during the period from November 2018 to January 2024, and MOG reviewed cases during the period from December 2019 to January 2024. Indirect immunofluorescence assay using formalin fixed cells is commercially available and compared to the FC-CBA of this institution. Results During the study period, 4,733 cases of AQP4 were performed, and 23,540 cases of MOG were performed by FC-CBA. Among them, AQP4 was positive in 405 cases (8.5%) and borderline in 71 cases (1.5%), and all others were negative. MOG was 2,597 positive (11%), borderline in 1,144 cases (4.8%), and all others were negative. The positive and borderline cutoffs for MFI ratio were changed during the study period, and the positive rate was significantly changed. Conclusions Eone laboratories are the only institution in Korea that performs live cell based assay using flow cytometry for AQP4 and MOG IgG, and receives samples from patients suspected of NMOSD at university hospitals. When reading with MFI ratio, it is important to properly set the cutoff to determine the positivity rate.

Smart Farming for Sustainable Agriculture: A Case Study through Korean Public TVET

This study aims to present implications for sustainable education and training of the agricultural workforce. It introduces the case of a smart farm learning factory as an educational facility at Korea Polytechnics. Learning factory refers to the practical experience gained using the knowledge acquired in engineering education to solve problems in the actual work field. For this study, we analyzed the smart farm case of Hongseong Campus of Korea Polytechnics, a government-funded vocational education institution in Korea. The research questions are as follows. First, what is the purpose of establishing a smart farm education and training facility? Secondly, what is the performance of the facility? Thirdly, what are the implications of the Korean smart farm for sustainable TEVT? As a result of analyzing the case, the purpose of establishing the facility was to improve the practical capabilities of convergence technologies used in machinery, automation, industrial facilities, and electrical departments. Additionally, the performance has been found to serve as the foundation for project-based learning subjects that incorporate convergence education, and companies have been able to reduce training costs and contribute to sales profits by using this facility to train employees. Finally, the implication of sustainable TVET through smart farm cases is that it has provided a way to enhance the effectiveness of teaching and learning guidance at agricultural sites, create educational resources that can utilize advanced agricultural technologies for sustainable development, and actively cooperate and collaborate with educational institutions, governments, and local companies.

Conceptual design study of the tritium breeding unit for verifying the long-term performance of the breeding blanket

Fusion reactors produce high-energy neutrons through the Deuterium-Tritium (DT) reaction. The long-term performance verification and structural integrity assessment of the breeding blanket under continuous plasma operation are essential for the development of Demonstration fusion power reactor (DEMO) breeding blankets. The Korea Institute of Fusion Energy (KFE) has been planning the construction of a test facility called the Integrated Breeding Test Facility (IBTF) that uses a linear accelerator as the neutron source. A solid beryllium target has been considered to generate fusion-like neutrons. A conceptual design of the Tritium Breeding Unit (TBU), which is a key component of the breeding blanket, has been carried out. This study evaluated tritium production under fusion-like conditions using factors such as the position and thickness of the graphite block, the thickness of the first wall, and the radial length of the breeding zone. The results showed that increasing graphite block thickness and optimizing the dimensions of the TBU enhanced tritium production. However, these changes affected the structural integrity of the TBU. The side wall of the TBU experienced membrane plus bending stress, which exceeded the Level C and D acceptance criteria under the assumption of In-Box LOCA. Measures were investigated to ensure structural integrity while improving tritium production of the TBU.

Evaluation of the Disk Diffusion Test for Bacteroides fragilis Group Clinical Isolates.

Bacteroides fragilis group (BFG) isolates are the most frequently isolated gram-negative anaerobic bacteria and exhibit higher levels of antimicrobial resistance than other anaerobic bacteria. Reliable susceptibility testing is needed because of reports of resistance to the most active antibiotics. Recently, the European Committee on Antimicrobial Susceptibility Testing (EUCAST) introduced disk zone diameter breakpoints. We evaluated the disk diffusion test (DDT) for susceptibility testing of BFG isolates compared with the agar dilution method. In total, 150 BFG isolates were collected from three institutes in Korea. The agar dilution method was conducted according to the CLSI guidelines. DDT was performed following the EUCAST guideline. Fastidious anaerobe agar supplemented with 5% defibrinated horse blood was used as the culture medium. Nine antimicrobials were evaluated: penicillin, cefoxitin, cefotetan, imipenem, meropenem, piperacillin-tazobactam, clindamycin, moxifloxacin, and metronidazole. The categorical agreement (CA) between the two methods was >90.0% for imipenem, meropenem, clindamycin, and metronidazole. However, the CA for piperacillintazobactam was low, at 83.2%. Major errors were found: 5.4% for imipenem, 7.4% for meropenem, and 12.8% for piperacillin-tazobactam. All minor errors were <10%. We propose using the area of technical uncertainty (ATU) zone-overlapping area for susceptible and resistant strains to reduce errors in the DDT. Outside the ATU, the CAs of cefoxitin, cefotetan, and piperacillin-tazobactam were >90.0%, whereas that of moxifloxacin was increased to 88.5%. The DDT can be a useful alternative antimicrobial susceptibility test for BFG isolates when using the ATU zone to reduce errors.

아동의 표현어휘 지연 예측 요인 연구: 3세 말늦은 아동과 정상 언어발달 아동의 가정환경의 질 차이를 중심으로

The purpose of this study is to examine the influence of home environment quality on children’s expressive vocabulary development by comparing the home environments of 3-year-old late talkers and typically developing children. The study used the data of 1,723 3-year-old children from the Korean Children’s Panel Study 4th wave data (2011) of the Korea Institute of Child Care and Education (KICCE). Frequency analysis, t-test, and logistic regression were performed to analyze the data. The Early Childhood HOME(ECHOME) was used to measure the quality of home environment and a new variable ‘overall home environment’ was created to represent the average of the six sub-domains of home environment quality. T-test results indicated significant differences in the overall home environment quality and every sub-domain between 3-year-old late talking children and typically developing children. Logistic regression analysis revealed that the overall home environment quality at the age of 3 was a significant predictor distinguishing the two groups. When all six sub-domains were included as an independent variable, learning materials and diversity demonstrated significant influences. This study emphasizes the significance of home environment quality as a predictor of expressive vocabulary delay and identifies specific sub-domains that influence children's language development.

Validation of the Mediating Effect of Parenting Stress in the Relationship between Work-Family Strains and Gains and Marital Satisfaction for Fathers in Korea.

This study aimed to examine the relationship between Korean fathers' work-family strains and gains and marital satisfaction and to validate the mediating effect of parenting stress in the relationship. This study used the 14th-year survey data of the Panel Study of Korean Children (PSKC) conducted by the Korea Institute of Child Care and Education (KICCE), the latest available data. The PSKC is a longitudinal study of children's growth and development from birth in the Republic of Korea. After excluding datasets containing missing values from the data collected from 2150 respondents, the data were extracted from the survey responses collected from 1130 respondents, and descriptive statistical analysis, path analysis, and mediating effect analysis were conducted. First, Korean fathers' work-family strains had a positive (+) influence on parenting stress (β = 0.658, p < 0.001). Second, Korean fathers' work-family strains had a negative (-) influence on marital satisfaction (β = -0.185, p < 0.001). Third, Korean fathers' work-family gains did not have a statistically significant influence on parenting stress (β = 0.016, p = 0.632). Fourth, Korean fathers' work-family gains had a positive (+) influence on marital satisfaction (β = 0.381, p < 0.001). Fifth, Korean fathers' parenting stress did not have a statistically significant influence on marital satisfaction (β = 0.011, p = 0.783). Sixth, the indirect effect of work-family strains on marital satisfaction via parenting stress (β = 0.013, 95% Bias-corrected CI = -0.042∼0.075) was statistically significant, and specifically, it had a partial mediating effect. Seventh, the indirect effect of work-family gains on marital satisfaction via parenting stress (β = 0.028, 95% Bias-corrected CI = 0.005∼0.051) was statistically significant, and specifically, it had a partial mediating effect. This study aims to provide the basic data for various family support policies for fathers by understanding the current status of work-family balance for fathers in modern society, as well as by examining the effects of parenting stress in the relationship with marital satisfaction.

The perception of HRM, trust between employees, and organizational satisfaction in public institutions: The case of Korea

This study examined the factors influencing the organizational satisfaction of employees in public institutions. In the case of public institutions that must provide stable public services on behalf of the government, the organizational satisfaction of employees will be more important. In this regard, this study includes the perception of HRM and trust between employees as affecting factors, and the perception of HRM consisted of sub-components such as fairness of evaluation and excellence of education and training. Moreover, this study considered trust between employees as a mediator. In more specific, online surveys were conducted with 705 employees of public institutions in Korea, and the Structural Equation Model (SEM) was performed. The results indicated that the perception of HRM affected organizational satisfaction directly or indirectly. In addition, trust between employees mediated between all sub-components of perception of HRM and organizational satisfaction. Particularly, trust between employees has been verified to increase the influence of the perception HRM. Meanwhile, in the case of Korea, there are more public institutions than other countries, and many other countries are showing high interest in Korea’s public institution operation system. In this respect, dealing with Korean public institutions as examples provides important international implications.

Assessment of high-resolution regional ocean reanalysis K-ORA22 for the Northwest Pacific

The Korea Institute of Ocean Science and Technology developed the Korea Operational Oceanographic System-Ocean Predictability Experiment for Marine Environment (KOOS-OPEM), a high-resolution (1/24°, 51 vertical levels) ocean prediction model for the Northwest Pacific Ocean that incorporates ensemble optimal interpolation. In this study, we present KOOS-OPEM ReAnalysis version 2022 (K-ORA22), which covers the period from 2011 to 2022. We conducted a comparative analysis between K-ORA22 and other high-resolution (1/10°–1/12°) global reanalyses, including the Hybrid Coordinate Ocean Model, Global Ocean Reanalysis and Simulation (GLORYS), and Bluelink ReAnalysis (BRAN), to demonstrate the reproducibility and reliability of regional characteristics. Statistical comparisons revealed that while K-ORA22 exhibited some warm biases, its sea surface temperature (SST) anomaly correlation after removing the seasonal cycle was approximately 0.87, comparable to other reanalyses. Additionally, K-ORA22 effectively reproduced coastal upwelling, which is characterized by a sharp decrease in SST, as observed by marine meteorological buoys in the Southwest of the East/Japan Sea. K-ORA22 exhibits a warm bias of approximately 0.50 °C around 200 m, slightly higher than those of GLORYS and BRAN, while maintaining a low salinity bias in the subsurface. Notably, K-ORA22 outperformed the other reanalyses in accurately reproducing the unique characteristics of North Pacific and East Sea intermediate waters, characterized by a salinity minimum layer. In addition, K-ORA22 stands out in its ability to accurately reproduce the Yellow Sea Cold Water Mass with a low-temperature root-mean-square error (RMSE) of 0.76 °C in the Yellow Sea (YS) region. However, it exhibited the highest RMSE for salinity in the YS region and Korea/Tsushima Strait, indicating a potential overestimation of river discharge from Korea and China. While the sea surface height (SSH) anomaly correlation of K-ORA22 did not surpass 0.80 in the entire region because of limitations in the background error covariance used, its ability to reproduce the Kuroshio path was comparable to those of other reanalysis datasets. In conclusion, K-ORA22 excels in reproducing the unique characteristics of Korean marginal seas. Still, it exhibits weaknesses, such as the overestimation of river discharge and a somewhat limited ability to simulate SSH variability, compared with other global reanalyses. We plan to enhance K-ORA22 by updating background error covariance, addressing biases related to river discharge and assimilating the best available in situ observations and satellite data.

Patterns of Health Behaviors and Trajectories of Stress among People with Disabilities in Korea.

As a health vulnerable group, people with disabilities require more health-promoting behavior than non-disabled people. We aimed to identify the types of health behavior of disabled people and to track the trajectories of stress by the type of health behaviors. Data came from the Panel Survey of Employment for the Disabled Second Wave by the Employment Development Institute (EDI) in Korea. We used dataset from the first 6 years of the 2nd wave of PSEDSW (2016-2021). The current study analyzed 3,991 subjects. The types of health behavior were identified through latent class analysis (LCA) and the trajectories of stress were estimated through multi-group latent growth modeling using Mplus 8.0. Two types of groups in health behaviors, smoking-drinking group (SD), nonsmoking-less drinking group (NLSD) were derived. Depending on the types of health behavior, the trajectories of stress appeared significantly different: the NLSD had significantly lower stress than the SD in the first year, and this low-level stress trajectory was maintained continuously for 6 years. Health behaviors could be suitable as a stress coping method for people with disabilities. This study suggests that it is necessary to make efforts to create an environment that supports people with disabilities to learn healthier ways to cope with stress.

Interinstitutional Comparison of Vancomycin Area Under the Concentration-Time Curve Estimation in Korea: Need for Standardized Operational Protocols for Therapeutic Drug Monitoring Consultation.

Vancomycin, a vital antibiotic for treating gram-positive bacterial infections, requires therapeutic drug monitoring (TDM) because of its substantial pharmacokinetic variability. While traditional TDM relies on steady-state trough concentrations, recent guidelines advocate the area under the concentration-time curve (AUC) as the target index. However, detailed protocols for AUC estimation are lacking, leading to potential discrepancies among institutions. We surveyed medical institutions in Korea regarding vancomycin TDM, including AUC estimation. Nineteen participants responded to the TDM case challenge under three patient scenarios. For an ordinary patient in Case 1, the overall CV for AUC values was 0.4% when both trough and peak concentrations were included in the AUC calculation and 1.9% when utilizing only the trough concentration. For Case 2, an older patient with obesity, the corresponding CV was 6.6%. For Case 3 with multiple trough concentrations, the CV was 15.6%, reflecting variations in the selective use of data. Although the agreements in Case 1 were good, significant variability in AUC estimation was noted in cases involving atypical patient characteristics or old TDM data. Our study provides insight into the current status of vancomycin TDM in Korea and underscores the need for standardized operational protocols for AUC estimation.

Lung Cancer Staging Using Chest CT and FDG PET/CT Free-Text Reports: Comparison Among Three ChatGPT Large-Language Models and Six Human Readers of Varying Experience.

Background: Although radiology reports are commonly used for lung cancer staging, this task can be challenging given radiologists' variable reporting styles as well as reports' potentially ambiguous and/or incomplete staging-related information. Objective: To compare performance of ChatGPT large-language models (LLMs) and human readers of varying experience in lung cancer staging using chest CT and FDG PET/CT free-text reports. Methods: This retrospective study included 700 patients (mean age, 73.8±29.5 years; 509 male, 191 female) from four institutions in Korea who underwent chest CT or FDG PET/CT for non-small cell lung cancer initial staging from January, 2020 to December, 2023. Examinations' reports used a free-text format, written exclusively in English or in mixed English and Korean. Two thoracic radiologists in consensus determined the overall stage group (IA, IB, IIA, IIB, IIIA, IIIB, IIIC, IVA, IVB) for each report using the AJCC 8th-edition staging system, establishing the reference standard. Three ChatGPT models (GPT-4o, GPT-4, GPT-3.5) determined an overall stage group for each report using a script-based application programming interface, zero-shot learning, and prompt incorporating a staging system summary. Six human readers (two fellowship-trained radiologists with lesser experience than the radiologists who determined the reference standard, two fellows, two residents) also independently determined overall stage groups. GPT-4o's overall accuracy for determining the correct stage among the nine groups was compared with that of the other LLMs and human readers using McNemar tests. Results: GPT-4o had an overall staging accuracy of 74.1%, significantly better than the accuracy of GPT-4 (70.1%, p=.02), GPT-3.5 (57.4%, p<.001), and resident 2 (65.7%, p<.001); significantly worse than the accuracy of fellowship-trained radiologist 1 (82.3%, p<.001) and fellowship-trained radiologist 2 (85.4%, p<.001); and not significantly different from the accuracy of fellow 1 (77.7%, p=.09), fellow 2 (75.6%, p=.53), and resident 1 (72.3%, p=.42). Conclusions: The best-performing model, GPT-4o, showed no significant difference in staging accuracy versus fellows, but significantly worse performance versus fellowship-trained radiologists. The findings do not support use of LLMs for lung cancer staging in place of expert healthcare professionals. Clinical Impact: The findings indicate the importance of domain expertise for performing complex specialized tasks such as cancer staging.