Anchoring CeF3 nanoparticles on porous carbon nanofibers as self-supporting electrodes for highly sensitive detection of nitrite.

Designing a working electrode is crucial for the reliable electrochemistry detection, which is applied to detect toxic and harmful substances sensitively and rapidly. Here we report the polytetrafluoroethylene decomposition-assisted electrospinning, a combination method for creating nanopore and synthesizing CeF3, to prepare the self-supporting electrode of CeF3 nanoparticles-anchored on porous carbon nanofibers (CeF3/PCNFs) for highly sensitive nitrite detection. The CeF3/PCNFs exhibits remarkable electroactivity toward nitrite detection, featuring a wide concentration range (0.5 µM-6 mM), low detection limit (10 nm) and high sensitivity (2093 µA mM-1 cm-2). It also exhibits excellent selectivity, stability and reproducibility, and powerful reliability for nitrite detection in saliva, pickles, sausages, chips, river water and tap water. This study provides a facile strategy to prepare the metal fluoride-based self-supporting electrode, which overcomes the disadvantages of chemically modified electrodes unstable and poorly reproducible, and is significant for clinical diagnosis, food safety and environmental monitoring.

[Clinical study of anti-Mullerian hormone in prediction of ovarian aging].

OBJECTIVE: To explore the serum anti-Mullerian hormone (AMH) level in women of childbearing age with normal menstrual cycles. METHODS: A total of 1 423 women with regular menstrual cycles were selected and divided into 5 groups according to their ages, i.e. ≤ 25, 26-30, 31-35, 36-40, ≥ 41 years. Their serum levels of AMH were measured, and the relationship between AMH and age was analyzed. RESULTS: The serum AMH levels of 5 groups according to ages (≤ 25, 26-30, 31-35, 36-40, ≥ 41 years) were 3.62, 3.10, 2.27, 1.07, 0.45 µg/L, respectively. The comparison of serum AMH levels in different age groups had significant difference (P < 0.01). Serum AMH level declined with increasing age, and dropped significantly after 36. The serum AMH level and age showed a negative correlation with significant difference (r = -0.374, P < 0.01). Quadratic regression of logAMH proximally reflected the relationship between AMH and age. CONCLUSION: AMH determination for women of childbearing age could provide reference for the evaluation of ovarian function.