Background: The risk of weight gain as a consequence of school closure in children during the coronavirus disease-2019 (COVID-19) pandemic has been recognized. This study was performed to investigate changes in anthropometric and metabolic parameters in children following a 6-month period of social distancing and school closure due to the pandemic. Methods: This retrospective cohort study was conducted in school-aged children that were on routine follow-up at the Growth Clinic of Seoul St. Mary's Hospital. Changes in body mass index (BMI) standard deviation scores (z-scores), lipid profiles, and vitamin D levels were investigated. The 1-year period prior to school closure was defined as "pre-COVID-19 period," and the subsequent 6-month period as "COVID-19 period." Results: Overall, 226 children between 4 to 14 years old without comorbidities were assessed. On average, their BMI z-scores increased by 0.219 (95% confidence interval [CI], 0.167-0.271; P < 0.001) in the COVID-19 period compared to the pre-COVID-19 period, and the proportion of overweight or obesity increased from 23.9% in the pre-COVID-19 period to 31.4% in the COVID-19 period. The number of days after school closure (P = 0.004) and being in the normoweight category in the pre-COVID-19 period (P = 0.017) were factors associated with an increased BMI in the COVID-19 period. The mean triglyceride (105.8 mg/dL vs. 88.6 mg/dL, P < 0.001) and low-density lipoprotein-cholesterol (100.2 mg/dL vs. 94.0 mg/dL, P = 0.002) levels were higher, whereas the calcidiol level (18.9 mg/dL vs. 23.8 mg/dL, P < 0.001) was lower in the COVID-19 period compared to the pre-COVID-19 period. Conclusion: Within 6 months, increased childhood obesity and vitamin D deficiencies were observed. The duration of school closure was significantly associated with an increased BMI and being normoweight does not exclude the risks for gaining weight.

Coupled guided modes, proposed in various modified hollow hexagonal cavities each attached internally to a hexagon, were demonstrated by investigating the laser oscillations in semiconductor cavities. The mode spacing between two adjacent lasing peaks decreased as the size of the internal hexagon increased, due to the increased round-trip length of the coupled guided modes. The linear dependency of the inverse mode spacing to the calculated round-trip length strongly confirmed the lasing of the coupled guided modes. The proposed modes in common-sized external cavities showed resonance structure that could be adjusted widely by controlling the size of the internal hexagon.

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Background AVN is a common manifestation in patients with systemic lupus erythematosus (SLE), which can cause significant disability. Nevertheless, the exact pathogenetic mechanism has not been clarified. Objectives To identify the risk factors for the development of avascular necrosis (AVN) and predictors for total hip replacement (THR) of the systemic lupus erythematosus (SLE) patients in Korea. Methods The medical records of 1051 patients with SLE were reviewed and 73 patients with AVN were identified. Among them, 64 patients were eligible for the analysis. Sixty-four age-and sex-matched SLE patients without apparent AVN were included as disease controls. The risk factors for development of AVN were examined by logistic regression analyses. The predictors for THR were determined by Cox proportional hazards regression analyses. Results Among 64 patients with AVN, 59 had AVN of the hip and 36 underwent THR. Independent risk factors for the development of AVN included cushingoid feature (OR 21.792, P=0.005), use of cyclophosphamide (OR 2.779, P=0.03) and azathioprine (OR 2.662, P=0.023). In Cox proportional hazards model, only advanced radiological stage of AVN (Association for Research on Osseous Circulation (ARCO) stage) was a statistically significant predictor for THR. In subgroup analysis with stage I-III AVN, multivariate Cox regression analysis showed NPSLE (HR 6.295, P= 0.001) and cumulative prednisolone dose in the first 6 months after AVN diagnosis >0.9g (HR 3.238, P= 0.034) were independent predictors. Conclusions The advanced ARCO stage at the onset of AVN is an independent risk factor for THR in SLE patients with AVN. In ARCO stage I-III AVN, patients with NPSLE and patients who received more than 0.9g of prednisolone during the first 6 months after AVN diagnosis are likely to undergo THR. Disclosure of Interest None Declared