Kyungbok University

Abstract Background Estimating infection risk from SARS-CoV-2 Omicron and post-Omicron subvariants is challenging due to the high number of unconfirmed infections. We compared breakthrough infection risks among individuals with hybrid, vaccine-only, and infection-only immunity in South Korea, incorporating laboratory-confirmed and serology-inferred infections. Methods Using nationwide surveillance data (August–December 2022), immunity was classified by vaccination history and spike (S) and nucleocapsid (N) antibody profiles. Outcomes were assessed using two definitions: conservative (laboratory-confirmed cases) and inclusive (serology-inferred infections identified by changes in N-antibody titers). Infection dates for unconfirmed events were imputed via predictive mean matching, enabling Kaplan–Meier analyses. Time-varying Cox models estimated log hazard ratios (log-HRs). Results Including serology markedly increased four-month cumulative infection risk estimates: hybrid immunity rose from 2% to 20%, infection-only from 4% to 24%, and vaccine-only from 30% to 40%. With these additional infections, the relative advantage of hybrid immunity narrowed. Under the conservative definition, log-HRs declined for vaccine-only vs hybrid (4.10 to 2.34) and infection-only vs hybrid (1.56 to 0.31). Under the inclusive definition, the vaccine-only log-HR fell from 3.44 to 0.13, and the infection-only log-HR shifted from 3.31 to −0.56, indicating greater protection for infection-only immunity by month four. Conclusions Because confirmed cases largely capture symptomatic disease, vaccination appears to provide added protection against severe outcomes, though this benefit wanes within months. The rapid decline of hybrid immunity and the large burden of unconfirmed infections highlight the need for routine serological surveillance to detect silent transmission and timely booster campaigns to mitigate severe disease during Omicron-driven waves.

Atopic dermatitis (AD) is a chronic inflammatory skin disorder that is characterized by pruritus, erythema, and eczematous lesions, and pruritus is often regarded as the most burdensome symptom that affects quality of life. Current therapies, including corticosteroids and immunosuppressants, are limited by their adverse effects, thus highlighting the need for safer alternatives. Corchorus olitorius extract (CE), a polyphenol- and flavonoid-rich leafy vegetable, has been reported to possess anti-inflammatory properties. However, its potential as an anti-hypersensitivity agent has not been systematically evaluated. In this study, we investigated the anti-inflammation and anti-hypersensitivity properties of CE using RAW 264.7 macrophages, HaCaT keratinocytes, and human mast cell-1, as well as NC/Nga mice with 2,4-dinitrochlorobenzene-induced AD-like lesions. CE exhibited no cytotoxicity and significantly suppressed nitric oxide, tumor necrosis factor-α, interleukin (IL)-6, IL-1β, and thymus and activation-regulated chemokine production. Furthermore, CE inhibited the degranulation of mast cells by reducing histamine and β-hexosaminidase release, thereby demonstrating anti-hypersensitivity activity. The oral administration of CE attenuated the scratching behavior and improved skin severity scores in NC/Nga mice, with effects at the highest dose comparable to that of dexamethasone. Collectively, these findings provide the first comprehensive evidence that CE alleviates AD-like symptoms by regulating inflammatory mediators and hypersensitivity responses, thus supporting its potential as a safe oral therapeutic or functional food candidate for AD.

BackgroundPulmonary rehabilitation improves exercise capacity, dyspnea symptoms, quality of life, and even survival in patients with chronic respiratory disease. Center-based pulmonary rehabilitation programs often face barriers, and alternatives to center-based rehabilitation are urgently needed.ObjectiveThis study aimed to evaluate the clinical efficacy of smartphone app–based pulmonary rehabilitation in patients with chronic respiratory diseases, including chronic obstructive pulmonary disease, interstitial lung disease, and bronchiectasis.MethodsThis randomized controlled trial recruited 90 participants, randomly allocated into intervention (n=60) and control (n=30) groups. The intervention group received a 12-week smartphone app–based rehabilitation program, while the control group received standard outpatient care. The primary outcomes were maximal oxygen consumption via cardiopulmonary exercise test and the chronic obstructive pulmonary disease assessment test (CAT) after a 12-week period. Based on changes in quality-of-life questionnaire index scores, quality-adjusted life years were calculated, and a cost-utility analysis was conducted. A feasibility trial was also conducted in 4 community primary health care clinics.ResultsOf the 70 participants (median age 65.5 years) who completed the follow-up visits, 67 were included in the per-protocol analysis. The intervention group (n=43) showed significant improvements compared with the control group (n=24) in CAT score (median 7.0, IQR 4.0-15.0 vs median 10.0, IQR 6.5-18.5; P=.04), and International Physical Activity Questionnaire score (median 1488.0, IQR 1250.3-3027.8 vs median 1164.0, IQR 618.8-2205.0; P=.04), but not maximal oxygen consumption. Clinical outcomes showed more prominent improvements among participants who were physically active or compliant with rehabilitation programs. In the user experience survey, around 80% (35/43) of participants in the intervention group found the app easy to use, and more than 60% (27/43) reported that it helped improve dyspnea symptoms. The mean total health care costs were US $495 in the control and US $523 in the intervention group, with no notable difference in the quality-adjusted life year distribution. In the feasibility trial, 24 participants completed follow-up visits, showing a significant reduction in CAT score (median 8.5, IQR 6.0-18.0 to median 5.0, IQR 2.0-7.5; P<.001) post rehabilitation. No participants experienced disease exacerbation or musculoskeletal injury related to the rehabilitation activities.ConclusionsThe randomized controlled trial demonstrated that a smartphone-based pulmonary rehabilitation program improved clinical outcomes, including quality of life, physical activity, and dyspnea, in patients with chronic respiratory diseases. Although physically active and program-compliant participants showed significant clinical improvements, the fact that less than half of the participants demonstrated good compliance warrants more robust strategies to enhance adherence in future programs. Additionally, our feasibility trial demonstrated the potential for rehabilitation programs for older adults with chronic respiratory diseases to be implemented in primary health care settings. This approach represents a novel, scalable model bridging hospital- and community-based care, demonstrating real-world feasibility for digital rehabilitation in chronic respiratory diseases.Trial RegistrationClinicalTrials.gov NCT05610358; https://clinicaltrials.gov/ct2/show/NCT05610358

Abstract We present another way to teach the least-action principle in classical mechanics. Beginning with Newton’s second law of motion, we keep finding equivalent propositions based mainly on the method of undetermined coefficients in a multivariable-dependent identity to arrive at the Euler–Lagrange equations and the conventional principle of stationary action $$\delta S=0$$ δ S = 0 with the boundary condition for the variation of the physical path. Pedagogically, by following the logical steps that we show, students can easily learn that Lagrangian mechanics naturally arises from Newtonian mechanics. This approach makes it further clear that Newton’s laws do not require the minimum action—true for a free particle, just as the shortest path between two points is a straight line. However, the action is not always the minimum once the potential energy is turned on. The derivation of the least-action principle from Newton’s second law may resemble Euclid’s approach to geometric axioms.

Background:Recently, along with the increase of the older adult population, the necessity of health management in daily life is emerging, and interest in the traditional oriental health management method, Yangsaeng, is increasing. This study was to provide a basis for future oriental health promotion intervention research by analyzing previous studies related to the Yangsaeng (oriental health management) of the older adults.Method:This study was a systematic review on older adults’ Yangsaeng. The databases used for literature search for data collection include PubMed, Ovid MEDLINE, Cumulative Index to Nursing and Allied Health Literature (CINAHL), Cochrane Library (CDSR), Research Information Sharing Service (RISS), Oasis, Korean Studies Information Service System (KISS), and DataBase Periodical Information Academic (DBpia). Analysis of the status by year, subject characteristics, study types, research design methods, and variables related to older adults’ Yangsaeng among previous studies related to older adults’ Yangsaeng published in academic journals from 1990 to 2021 was performed.Results:Eighteen quantitative studies related to the older adults’ Yangsaeng have been published so far, and all of them were descriptive research studies using Yangsaeng measurement tool. The variables related to the older adults’ Yangsaeng identified in this study were activities of daily living, self-efficacy, instrumental activities of daily living, perceived health state, self-esteem, empowerment, life satisfaction, physical function, quality of life, social support, anxiety, and depression.Conclusion:The study will be helpful in the development of integrative and complementary interventions for health promotion of the older adults.

IntroductionBiodegradable mulching films (BDMs) are sustainable alternatives to polyethylene, but their degradation efficiency is strongly influenced by soil microbial composition. This study investigated the effects of Bacillus subtilis and Clostridium perfringens, two soil bacteria with distinct metabolic traits, on the decomposition of BDMs with different structures.MethodsThree biodegradable films (BDM1, BDM2, BDM3) and a polyethylene control were buried in soils containing native microbes, B. subtilis, or C. perfringens and incubated for 210 days. Degradation was evaluated by weight loss, soil pH, microbial viability, and scanning electron microscopy (SEM) of surface morphology.ResultsAll BDMs degraded significantly more than polyethylene. The monolayer BDM3 exhibited the greatest weight loss and surface damage. Soils inoculated with C. perfringens underwent strong acidification (final pH < 5.5), which accelerated degradation, especially in CaCO₃-containing films. Although C. perfringens viability declined over time, accumulated acids sustained film breakdown. By contrast, B. subtilis maintained higher soil populations, promoted gradual degradation, and preserved near-neutral pH, resulting in moderate weight loss.DiscussionThese findings demonstrate that soil pH modulation and microbial activity jointly determine BDM degradation. While C. perfringens enhanced film loss through acidification, its agricultural use may pose risks including excessive soil acidification and pathogenicity. B. subtilis provided safer but slower biodegradation. Among the tested films, monolayer BDM3 was most susceptible to breakdown, making it a promising candidate for field application. Careful management of microbial inoculants and soil pH will be essential to maximize BDM performance and environmental safety.

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is an acquired immune-mediated disorder characterized by weakness and sensory deficits.Charcot-Marie-Tooth type 1 (CMT1) is a slowly progressive hereditary degenerative disease.This study quantitatively analyzed the electrophysiological characteristics observed in motor nerve conduction studies for both diseases.This retrospective study included 80 patients diagnosed with CIDP (n=47) or CMT1 (n=33) and healthy controls (n=77).This study conducted a stepwise analysis of distal compound muscle action potential (dCMAP) amplitude, motor nerve conduction velocity (MNCV), proximal/distal CMAP amplitude ratio, and correlation analysis of MNCV.CMT1 showed more severe polyneuropathy than CIDP according to the no-potential rate, dCMAP amplitude, or MNCV.Statistical stepwise analysis of dCMAP and MNCV revealed more severe neuropathy in the lower extremities in both diseases and damage to the peroneal nerve was most severe.Proximal/distal CMAP amplitude ratio analysis revealed CIDP to have a significantly lower amplitude than CMT1.Correlation analysis and Fisher's Z test conducted with MNCV showed that CIDP exhibited conduction block and asymmetric nerve damage patterns.Some other atypical variants have been reported, highlighting the need for further research from various perspectives.

BackgroundIn intensive care units, nurses’ management of healthcare-related infections is an important task that affects patient recovery, length of hospitalization, and medical costs. This study aimed to examine the relationships among health beliefs, knowledge, and performance related to standard precautions, and the factors influencing performance of standard precautions of intensive care unit nurses.MethodsA cross-sectional descriptive design was employed. Participants were 113 nurses with three months or over of work experience in the intensive care units (ICU) at the K University Hospital in South Korea. Measures were the general characteristics list, the health beliefs scale, the knowledge scale, and the performance scale of standard precautions. Data were collected from October to December, 2023. Data were analyzed using SPSS PC + version 29.0 statistical software program.ResultsThe health beliefs of standard precautions (β = 0.40, P < 0.001), work experience in the current department (β = 0.24, P = 0.019), and educational background (β = -0.23, P < 0.044) were statistically significant factors influencing performance of standard precautions of ICU nurses. The explanatory power of the final regression model was 47.0%.ConclusionThe health beliefs of standard precautions were important factor associated with performance of standard precautions of ICU nurses. Interventions strengthening health beliefs of standard precautions could improve performance of standard precautions. Increasing work experience in the current department and educational level need to be considered when developing and implementing interventions. ICU nurses should pay attention to factors influencing performance of standard precautions in hospital.