The Impact of the Coronavirus Disease-2019 Pandemic on Childhood Obesity and Vitamin D Status.

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.

A green preparation of nitrogen doped graphene using urine for oxygen reduction in alkaline fuel cells.

A simple, eco-friendly and efficient harmless chemical approach has been developed for the simultaneous nitrogen (N) doping and reduction of graphene oxide (GO) by cost free human urine using simple refluxing. Large-scale preparation of graphene has been hindered largely by several issues, such as highly toxic reducing agents that are harmful to human health and environment, complicated reduction process and costly chemicals. Human urine is a natural precursor of urea with no cost. In this process, the NH3 has acted as not only reducing but also doping agent that produced via thermal decomposition of urea, while the N doping level of ~11.1 at% is achieved. For the first time we have used urine as a reductant and doping agent in such a high class chemical technology. The simultaneous reduction and N-doping of GO using urine (denoted as UNG) have confirmed by X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, Raman spectroscopy, and UV-vis spectroscopy. The resultant UNG has demonstrated to show remarkable electrocatalytic activity toward oxygen reduction reaction (ORR) with better fuel selectivity, and stability than that of the commercially available 20 wt% Pt/C electrode using cyclic voltammetry (CV) and chronoamperometry.

A lead(II)-selective PVC membrane based on a Schiff base complex of N,N'-bis(salicylidene)-2,6-pyridinediamine.

PVC membrane electrodes for lead ion based on N,N'-bis(salicylidene)-2,6-pyridinediamine as membrane carrier were prepared. Among their membranes, a membrane electrode (m-3) containing o-NPOE as a plasticizer and 50mol% additive displays an excellent Nernstian response (29.4mV/decade) and the limit of detection of -loga (M) = 6.04 to Pb(2+) in Pb(NO(3))(2) solutions at room temperature. It has a rapid response time within 10s over the entire concentration range. The proposed electrode revealed good selectivity and response for Pb(2+) over a wide variety of other metal ions in a pH 5.0 buffer solutions, and good reproducibility of base line in subsequent measurements.