Korea National Open University

Purpose: This study compared key health indicators of poor, older urban adults attending a free clinic with those of the general older population, using data from the 2023 Korea National Health and Nutrition Examination Survey (KNHANES). Methods: This cross-sectional comparative study included 60 adults aged ≥60 years who attended the Raphael Nanum Homeless Clinic in Seoul. Participants completed a questionnaire, underwent anthropometric assessment, and provided fasting blood samples for measurement of total cholesterol, low density lipoprotein (LDL)-cholesterol, and triglycerides (TG). Obesity, current smoking, monthly alcohol use, poor self-rated health, and strength exercise (≥ 2 days/week) were defined according to 2023 KNHANES criteria and compared with age-matched 2023 KNHANES estimates for adults aged ≥ 60 years using independent t-tests and two-proportion z-tests. Results: Participants were predominantly men (80.0%) with a mean age of 79.9 years; 70.0% reported no regular income, and 46.7% rated their health as poor. Compared with their 2023 KNHANES counterparts, the clinic group had a higher prevalence of obesity (50.0% vs. 35.0%), particularly among men, and a more atherogenic lipid profile characterized by higher LDL-cholesterol despite similar total cholesterol levels and lower TG. The prevalence of current smoking (3.3% vs. 10.6%) and monthly alcohol use (31.7% vs. 53.0%) was significantly lower, whereas participation in strength exercise was low in both groups, with no significant differences observed. Conclusion: Poor, older urban adults exhibited multidimensional health disparities, including obesity, adverse lipid profiles, and markedly poorer self-rated health, despite lower levels of smoking and alcohol consumption. Community-based interventions targeting nutrition, physical activity, and chronic disease management are needed to reduce health inequalities in this vulnerable population.

The objective of this study was to evaluate the antiviral activity of glucosyl hesperidin (GH), a water-soluble derivative of hesperidin with known antioxidant and anti-inflammatory properties, in order to explore its potential applications. Antiviral activity was assessed using feline calicivirus (FCV), a surrogate model for human norovirus, a major foodborne pathogen. Cytotoxicity testing in Crandell–Rees feline kidney (CRFK) cells demonstrated that GH exhibited high biocompatibility, maintaining 100% cell viability at concentrations up to 8000 μM. Antiviral efficacy assays revealed that GH inhibited FCV replication in a concentration-dependent manner across the range of 250~8000 μM, with a half-maximal inhibitory concentration (IC50) of 3281 μM. Complete viral inhibition, however, was not achieved at the maximum concentration tested. In conclusion, GH was shown to inhibit FCV while maintaining low cytotoxicity, indicating its potential as a natural, water-soluble candidate for the suppression of norovirus.

This study examined distance learner resilience in overcoming academic burnout during their research in the English department. The descriptive qualitative and quantitative approaches were used to evaluate the experiences and perspectives of 144 distance learners on their self-directed learning activities from the Undergraduate and Graduate English Education Study Programs at Universitas Terbuka (UT). The findings revealed that a strong support system is important in enhancing learners' resilience in distance higher education. Support from family and institutions contributes to their emotional and academic stability, while community engagement and access to digital resources expand learning opportunities and overcome barriers. In addition, the balance between online learning and personal life is key to preventing academic burnout and maintaining learning motivation. Therefore, educational institutions need to develop holistic support strategies, covering emotional, social, and managerial aspects for distance learners.

Abstract This study investigated the effects of feature augmentation, which uses generated images with specific imaging features, on the performance of isocitrate dehydrogenase (IDH) mutation prediction models in gliomas. A total of 598 patients were included from our institution (310 training, 152 internal test) and the Cancer Genome Atlas (136 external test). Score-based diffusion models were used to generate T2-weighted, FLAIR, and contrast-enhanced T1-weighted image triplets. Three neuroradiologists independently assessed visual Turing tests and various morphological features. Multivariable logistic regression models were developed using real images, random augmented data, and feature-augmented datasets. While random augmentation yielded models with AUCs comparable to real image-based models, it led to reduced specificity, particularly in the external test set (specificity: 83.2% vs. 73.0%, P = .013). In contrast, feature-augmented models maintained stable diagnostic performance; however, when more than 70% of training images included synthetic T2-FLAIR mismatch signs, AUC decreased in the external test set (AUC: 0.905–0.906 for ≤ 70%; 0.902–0.876 for ≥ 80%). These findings highlight the value of phenotype-specific augmentation for IDH prediction, while emphasizing the need to optimize augmentation proportion to avoid performance degradation.

Nitrate and organic components have been considered key contributors to high PM 2.5 concentrations in Korea. This study examines the chemical evolution of aerosol species influenced by atmospheric ammonia (NH 3 ) in Hongseong county, Chungcheongnam-do, Republic of Korea, during late spring 2024 (May 20 – June 18), a period characterized by intensive agricultural activity. Using an aerosol chemical speciation monitor and ammonia analyzer, an ammonium-rich atmospheric state (average NH 3 concentration: 26.7 ± 12.4 ppb) was observed, with notable contributions from ammonium (NH 4 + ), nitrate (NO 3 - ), and sulfate (SO 4 2- ), especially under high-humidity conditions. The relative contributions of nitrate to PM 2.5 for low (0–15 μg/m 3 ), medium (16–30 μg/m 3 ), and high (over 30 μg/m 3 ) concentration intervals were 13.8%, 23.4%, and 29.6%, respectively. Elevated relative humidity (RH), averaging 63.1% (low), 82.3% (medium), and 91.7% (high), played a significant role in nitrate formation for those concentration intervals. Elevated nighttime ammonium conversion ratios (NHR) highlighted the importance of abundant atmospheric NH 3 under high RH conditions, facilitating effective heterogeneous uptake and subsequent particulate ammonium formation. Source tracking using the conditional bivariate probability function (CBPF) model identified agricultural fields, power plants, and industrial complexes as major sources of precursor emissions. These results emphasize the need to control emissions of NH 3 , SO 2 , and NOx in rural areas to mitigate PM 2.5 pollution and improve air quality. • Ammonia is a key precursor for the formation of secondary inorganic aerosols. • Relationship of RH with NOR reflects heterogeneous uptake of NO 2 or hydrolysis of N 2 O 5 on wet aerosols. • NOR and NHR demonstrated a strong positive correlation with relative humidity. • Reducing NO x concentrations is essential for controlling high levels of PM 2.5 . • Regions with complex precursor gas emission sources and high RH amplify the formation of secondary inorganic aerosols.