Association between serum vitamin D levels and visceral adipose tissue among adolescents: a cross-sectional observational study in NHANES 2011-2015.

BACKGROUND: In recent years, obesity and vitamin D deficiency are more prevalent among adolescents. Improving our knowledge of the link between vitamin D and visceral adipose tissue (VAT) is essential for the health of adolescents. This study aimed to examine the connection between serum vitamin D levels and VAT mass among adolescents participating in the United States. METHODS: This is a cross-sectional study that used data from the 2011 to 2015 National Health and Nutrition Examination Survey (NHANES). The connection between serum vitamin D levels and VAT was investigated using weighted multiple linear regression models. Potential nonlinear relationships were explored using smooth curve fitting. RESULTS: The analysis included 3171 adolescents aged 12-19 years. Vitamin D levels were shown to be inversely linked with VAT in the full-adjusted model (ß = - 0.34, 95% CI: - 0.49 to - 0.19). When stratified analyses by gender, this negative relationship persisted in the girls' group (ß = - 0.39, 95% CI: - 0.60 to - 0.19), but not in the boys' group (ß = - 0.06, 95% CI: - 0.25 to 0.13). When stratified analysis by race, this negative relationship persisted in the Mexican American group (ß = - 0.61, 95% CI: - 1.03 to - 0.19), and the non-Hispanic White group (ß = - 0.27, 95% CI: - 0.54 to - 0.01), but not in the other groups. CONCLUSIONS: Our findings confirmed that serum vitamin D levels negatively correlated with VAT among adolescents in the United State, especially in girls, the Mexican American and non-Hispanic White. Further research is needed to determine whether increasing serum vitamin D levels decrease VAT among adolescents.

[The reliability and accuracy of the digital models reconstructed by cone-beam computed tomography].

PURPOSE: To evaluate the reliability of the digital models scanned by cone-beam computed tomography (CBCT). METHODS: Forty plaster models of patients with orthodontic treatment were selected. These plaster models were scanned and measured by 3DX cone beam CT, compared with manual measurement via concordance correlation coefficient (CCC) and mean difference (MD). RESULTS: The CCC of all the measurement was from 0.847 to 0.993. The value of MD of all the measurement was below 0.25mm except CFF6, PWF5 and PWF6, which was 0.34mm, 0.63mm and 1.49mm, respectively. CONCLUSIONS: The reliability and accuracy of the digital models scanned by cone-beam CT is very high. The accuracy of measurement of the dental cusp is the highest, the dental fossa is the second, and the lowest point of palatal gingival is the third.

Ion-implanted optical-stripe waveguides in neodymium-doped calcium barium niobate crystals.

We report on the fabrication and characterization of optical-stripe waveguides in neodymium-doped calcium barium niobate (Nd:CBN) crystals by using He ion implantation assisted with a mask. The guided-mode profiles are successfully modeled through numerical simulations. After annealing at 200 degrees C for 30 min, the waveguide propagation loss could be reduced down to ~3 dB/cm. Room-temperature microluminescence and micro-Raman investigations reveal that the crystal bulk features are well preserved in the active volume of the waveguide, suggesting possible applications as integrated photonic devices.