One-pot green preparation of deep-ultraviolet and dual-emission carbon nanodots for dual-channel ratiometric determination of polyphenol in tea sample.

A novel deep-ultraviolet and dual-emission carbon nanodots (DUCDs)-based dual-channel ratiometric probe was prepared by a one-pot environmental-friendly hydrothermal process using guanidine as the only starting material for sensing polyphenol in tea sample (TPPs). Under the exposure to TPPs, the DUCDs not only provided a characteristic colorimetric response to TPPs, but also displayed TPPs-sensitive ratiometric fluorescence quenching. The detection mechanism was proved to be that enrichment-specific hydroxyl sites (e.g., -NH2 and -COOH) of DUCDs can specifically react with phenolic hydroxyl groups of TPPs to generate dynamic amide and carboxylate bonds by dehydration and/or condensation reaction. As a result, a new carbon nanomaterial with decrement of surface passivation groups, inherent light-absorbing, and invalid fluorescence emission was generated. The ratio (FL297nm/FL395nm) of fluorescence intensity at 297 nm and 395 nm of DUCDs excited at 275 nm decreased with increasing TPPs concentration. The linearity range was 5.0 ng/mL to 100 µg/mL with a detection limit (DL) of 3.5 ± 0.04 ng/mL for TPPs (n = 3, 3σ/k). Colorimetry of DUCDs, best measured as absorbance at 320 nm, was increased linearly in the TPP concentration range 200 ng/mL-200 µg/mL with a DL of 94.7 ± 0.04 ng/mL (n = 3, 3σ/k). The probe was successfully applied to the determination of TPPs in real tea samples, showing potential application prospects in food analysis.

[Effect of electroacupuncture combined with auricular point tapping and pressing on serum insulin and testosterone in the patients of obese women with polycystic ovary syndrome].

OBJECTIVE: To assess the therapeutic effect and mechanism of electroacupuncture combined with auricular point tapping and pressing on the obese women with polycystic ovary syndrome. METHODS: Thirty-nine cases of obese women with polycystic ovary syndrome were treated with electroacupuncture combined with auricular point tapping and pressing, body points as Tianshu (ST 25), Fenglong (ST 40), Guanyuan (CV 4) and Siman (KI 14) etc. were selected, and ear points as Kou (mouth), Wei (stomach) and Pi (spleen) etc. were selected. After 3 courses, the therapeutic effect, the body mass index (BMI), the waist circumference (WC) and the changes of the serum insulin (Ins) and testosterone (T) were compared before and after treatment. RESULTS: Of the 39 cases, 10 cases were cured, 25 cases were effective, 4 cases were ineffective, with a total effective rate of 89.7%; there were significant differences in BMI, WC, Ins and T of the patients compared with that before treatment (all P < 0.01). CONCLUSION: Electroacupuncture combined with auricular point tapping and pressing has a good clinical effect on obese women with polycystic ovary syndrome, the treatment mechanism may realized by regulating the serum insulin and the testosterone of the patients.