Hand and Oral Hygiene Practices of South Korean Adolescents Before and During the COVID-19 Pandemic.

Importance: Only a few studies have examined the long-term trends of hand and oral hygiene, especially among adolescents. Objective: To investigate the 15-year trends in frequency of handwashing and toothbrushing and examine the factors associated with hand and oral hygiene, particularly during the COVID-19 pandemic. Design, Setting, and Participants: This cross-sectional study, performed from January 1, 2008, to December 31, 2022, used general population-based data from 963 644 individuals in a national representative survey (Korea Youth Risk Behavior Web-based Survey [KYRBS]). Exposure: COVID-19 pandemic. Main Outcomes and Measures: Trends in hand and oral hygiene practices were measured by how frequently adolescents washed their hands and whether they fulfilled the recommended guidelines for toothbrushing. An interrupted time series analysis using linear and logistic regression models was performed to assess any associations with the COVID-19 pandemic. Hand and oral hygiene behaviors before and during the pandemic in each sociodemographic subgroup were also compared. Results: In the 963 644 adolescents (495 697 [51.4%] male; mean [range] age, 15.01 [12-18] years) who participated in the KYRBS from 2008 to 2022, a 73.3% (95% CI, 59.4%-97.4%; P < .001) immediate increase was seen in overall hand hygiene behavior at the onset of the COVID-19 pandemic compared with the prepandemic period, with a sustained decrease thereafter (ß = -0.018; 95% CI, -0.022 to -0.015; P < .001). Meanwhile, no immediate increase was observed in terms of overall oral hygiene behavior (0.1%; 95% CI, -0.9% to 1.1%; P = .82); however, there was a sustained decrease during the pandemic (ß = -0.018; 95% CI, -0.020 to -0.016; P < .001). Older age, female sex, nonsmoking status, alcohol use, low household economic level, and poor school performance were significantly associated with poor hand hygiene during the pandemic. Conclusions and Relevance: In this cross-sectional study of South Korean adolescents, an increase in the prevalence of hand hygiene was observed during the early pandemic; however, this prevalence decreased over time. Meanwhile, the decrease in the prevalence of oral hygiene was more pronounced during the pandemic. This study recommends stronger guidelines for adolescent health coaches, such as teachers or public health advisers, regarding hygiene behaviors, even after the COVID-19 pandemic ends.

National trends in rheumatoid arthritis and osteoarthritis prevalence in South Korea, 1998-2021.

Studies on the trends in the prevalence of rheumatoid arthritis (RA) and osteoarthritis (OA) are limited, particularly during the COVID-19 pandemic. This study aimed to analyze the temporal trend of RA and OA in South Korean adults from 1998 to 2021, including the COVID-19 pandemic period. The Korea National Health and Nutrition Examination Survey (KNHANES) data on adults aged ≥ 19 years were analyzed to investigate the prevalence of RA and OA from 1998 to 2021. The prevalence trends were compared by the years, and ßdiff (ß difference) was calculated. Odds ratios (ORs) were computed for each disease to examine changes in disease prevalence before and during the pandemic in order to determine the impact of the pandemic on disease prevalence. Among 163,221 Korean adults, the prevalence of RA and OA showed a steady decrease from 2005 (RA: from 1.91% in 2005-2007 to 1.55% in 2016-2019 and OA: from 9.75% in 2005-2007 to 8.27% in 2016-2019), but there was a slight increased after the onset of the COVID-19 pandemic (RA: from 1.23% in 2020 to 1.36% in 2021 and OA: from 8.04% in 2020 to 8.27% in 2021). Vulnerable groups, including participants aged ≥ 60 years (versus 19-60 years, ratio of ORs: 1.222; 95% CI 1.011-1.477), urban residents (ratio of ORs: 1.289; 95% CI 1.007-1.650), and participants with higher education level (ratio of ORs: 1.360; 95% CI 1.119-1.653) showed higher ORs of OA, whereas no particularly vulnerable population was observed for RA. Our findings provide an insight into the long-term trends of RA and OA among adult population and highlight a novel perspective on the impact of COVID-19 on disease prevalence.

Preventing Overgrowth of Cucumber and Tomato Seedlings Using Difference between Day and Night Temperature in a Plant Factory with Artificial Lighting.

This study aimed to determine the feasibility of temperature difference as an overgrowth-prevention technique to influence plant height and internode length in a plant factory with artificial lighting. The control plants were grown in a commercial nursery greenhouse using a growth regulator (Binnari), and +DIF (25 °C/15 °C), 0DIF (20 °C/20 °C), and -DIF (15 °C/25 °C) were the treatments with different day/night temperatures and the same average temperature (20 °C). Cucumbers showed the strongest suppression under the -DIF treatment, with a dwarfism rate of 33.3%. Similarly, tomatoes showed 0.8% and 22.2% inhibition in the 0DIF and -DIF treatments, respectively. The FV/FM of cucumber was approximately 0.81 for all treatments. The OJIP changes differed for cucumbers; however, both cucumbers and tomatoes had similar OJIP curve patterns and no abnormalities. The relative growth rate of cucumbers at the growth stage was 1.48 cm·cm·day-1 for days 6-9 in +DIF stage 3, which was the highest growth rate among all treatments, and 0.71 cm·cm·day-1 for days 3-6 in -DIF stage 1, which was the most growth-inhibited treatment. In tomatoes, we found that days 3-6 of -DIF stage 1 had the most growth inhibition at 0.45 cm·cm·day-1. For cucumber, -DIF days 3-6 had the most growth inhibition, with a relative growth rate of 0.71 cm·cm·day-1, but the fidelity was significantly higher than the other treatments, with a 171% increase. The same was true for tomatoes, with days 3-6 of -DIF stage 1 showing the most inhibited growth at 0.45 cm·cm·day-1 but a 200% increase in fidelity. Therefore, applying the -DIF treatment at the beginning of growth would be most effective for both cucumbers and tomatoes to prevent overgrowth through the DIF in a plant factory with artificial lighting because it does not interfere with the seedling physiology and slows down the growth and development stage.

Performance Enhancement of Silicon Alloy-Based Anodes Using Thermally Treated Poly(amide imide) as a Polymer Binder for High Performance Lithium-Ion Batteries.

The development of silicon-based anodes with high capacity and good cycling stability for next-generation lithium-ion batteries is a very challenging task due to the large volume changes in the electrodes during repeated cycling, which results in capacity fading. In this work, we synthesized silicon alloy as an active anode material, which was composed of silicon nanoparticles embedded in Cu-Al-Fe matrix phases. Poly(amide imide)s, (PAI)s, with different thermal treatments were used as polymer binders in the silicon alloy-based electrodes. A systematic study demonstrated that the thermal treatment of the silicon alloy electrodes at high temperature made the electrodes mechanically strong and remarkably enhanced the cycling stability compared to electrodes without thermal treatment. The silicon alloy electrode thermally treated at 400 °C initially delivered a discharge capacity of 1084 mAh g(-1) with good capacity retention and high Coulombic efficiency. This superior cycling performance was attributed to the strong adhesion of the PAI binder resulting from enhanced secondary interactions, which maintained good electrical contacts between the active materials, electronic conductors, and current collector during cycling. These findings are supported by results from X-ray photoelectron spectroscopy, scanning electron microscopy, and a surface and interfacial cutting analysis system.