[Genesis study of omphacite at high pressure and high temperature].

The melting and recrystallizing experiments of alkali basalt powder and mixture of pure oxides mixed as stoichiometry were performed at 3 GPa and 1 200 degrees C. Electronic microprobe analysis and Raman spectra showed that the recrystallized products were omphacites, the FWHM (full width at half maximum) of the Raman peak was narrow and its shape was sharp, which is attributed to the stable Si-O tetrahedral structure and the high degree of order in omphacite. Based on the results of previous studies, the influencing factors of omphacite genesis and its primary magma were discussed. The results showed that the formation of omphacite could be affected by many factors, such as the composition of parent rocks, the concentration of fluid in the system and the conditions of pressure and temperature. This result could support some experimental evidences on the genesis studies of omphacite and eclogite.

Association between Serum Cotinine Levels and Bone Mineral Density: An Analysis of the National Health and Nutrition Examination Survey (NHANES).

Purpose: To investigate the relationship between serum cotinine and lumbar bone mineral density (BMD) among 7905 participants aged 30 years and over. Method: A total of 3945 men and 3960 women from the National Health and Nutrition Examination Survey 2011-2018 were included in this cross-sectional analysis. Independent variable was serum cotinine, which is a biomarker of cigarette exposure. The outcome variable was lumbar BMD. We investigated the associations of serum cotinine levels and lumbar BMD using multivariable linear regression models. Results: Serum cotinine concentration was negatively associated with lumbar BMD after adjustment of relevant covariables (ß = -0.039, 95% CI: -0.078 to -0.014, P = 0.005). However, in the subgroup analysis stratified by gender, this negative association remained only in women (ß = -0.072, 95% CI: -0.132 to -0.012, P = 0.019). Conclusion: Our study suggested that elevated serum cotinine level correlated with decreased lumbar BMD, especially in women. This finding indicated that reducing cigarette exposure and maintaining serum cotinine at a low level may be beneficial to bone health for adults.