An ultrastable 1397-nm laser stabilized by a crystalline-coated room-temperature cavity.

State-of-the-art optical cavities are pivotal in pushing the envelope of laser frequency stability below 10-16. This is often achieved by extending the cavity length or cooling the system to cryogenic temperatures to reduce the thermal noise floor. In our study, we present a 30-cm-long cavity that operates at room temperature and is outfitted with crystalline coatings. The system has a predicted ultralow thermal noise floor of 4.4 × 10-17, comparable to what is observed in cryogenic silicon cavities. A 1397-nm laser is stabilized in this advanced cavity, and the stable frequency is then transferred to the clock transition in strontium optical lattice clocks via a frequency-doubling process. We have meticulously minimized and assessed the technical noise contributions through comparisons with an ultrastable reference laser that is locked to a commercially available 30-cm cavity. The frequency instability of the system is rigorously evaluated using a three-cornered-hat method. The results demonstrate that the laser frequency instability remains below 2 × 10-16 for averaging times ranging from 1 to 50 s. These findings underscore the significant potential of room-temperature cavities with crystalline coatings in high-precision metrology and pave the way for further improvements in optical lattice clocks.

[Effects of DCC gene on cell growth and chemosensitivity of ovarian epithelial carcinoma cells].

OBJECTIVE: To study the effects of DCC gene transfection on cell-growth and chemosensitivity of ovarian epithelial carcinoma cell line HO8910. METHODS: Recombinant eukaryotic expression vector pcDNA3.1(+)-DCC containing DCC gene was introduced by lipofectamine transfection reagent into ovarian epithelial carcinoma cell line HO8910 which does not express DCC endogenously. The expression of DCC was detected by RT-PCR and immunocytochemistry. The cell proliferation and the viability rate after different concentrations of cisplatin and paclitaxel were given were assessed by methyl thiazolyl tetrazolium (MTT) assay. RESULTS: Exogenous DCC gene had been successfully transferred into HO8910 cells and obtained permanent expression. The growth speed of HO8910-DCC cells was significantly slower than other two groups. There was a significant difference between them (P < 0.01) except at the first day after being planted. There was no difference between the growth speed of HO8910 cells and that of HO8910-Neo cells (P > 0.05). The viability rate of HO8910-DCC cells was significantly lower than other two groups after (0.1 - 5.0) peak plasma concentration (PPC) of cisplatin and paclitaxel were given (P < 0.01). The viability rate of HO8910-DCC cells was lower than other two groups after 10.0 PPC concentration of cisplatin was given (P < 0.05), but there was no difference between them after 10.0 PPC concentration of paclitaxel was given (P > 0.05). The viability rate of HO8910 cells was similar to HO8910-Neo cells after different concentrations of cisplatin and paclitaxel were given (P > 0.05). CONCLUSION: The DCC gene expression not only inhibits cell growth but also enhances the chemosensitity of ovarian epithelial carcinoma cell line HO8910.

Analysis on Chemical Characteristics of Lycii Fructus in Qinghai Province Based on 1H-NMR Plant Metabolomics / 中国实验方剂学杂志

Objective:The chemical differences of Lycii Fructus samples from Qinghai, Ningxia, Gansu, Xinjiang and Inner Mongolia provinces were compared based on proton nuclear magnetic resonance (1H-NMR) plant metabolomics. Method:A total of 97 Lycii Fructus samples from five provinces were collected, including 61 samples in Qinghai, and extracted by 50% methanol for detecting. 1H-NMR spectra were obtained and compared by multivariate statistical analysis for investigating the chemical differences of samples from Qinghai and other production areas. And the content of Lycii Fructus polysaccharides in all samples was determined with the wavelength of 490 nm (calculated by anhydrous glucose). Result:A total of 32 chemical components were detected in the Lycii Fructus extract by 1H-NMR. The multivariate statistical analysis revealed that there was no significant difference among the samples from five provinces. The difference between Lycii Fructus from Qinghai and Ningxia, as well as the samples among the six regions of Qinghai province were relatively small. The similarity values of the majority of samples were >0.85. Univariate analysis showed that no significant difference was observed for the most metabolites in Lycii Fructus collected from five provinces, except for sucrose, glucose, proline and so on. There was no significant difference in the content of Lycii Fructus polysaccharides between Qinghai and other provinces. And the correlation coefficient between the content of Lycii Fructus polysaccharides and the small molecular compounds identified by 1H-NMR was -0.2-0.4. Conclusion:In this study, chemical characteristics of Lycii Fructus in Qinghai province are analyzed from the holistic view by 1H-NMR plant metabolomics, in combination of polysaccharide determination, and the results show that there is no significant difference between samples from Qinghai and other four provinces. The quality evaluation method based on 1H-NMR established in this study can provide scientific basis for improving quality control level and selecting planting areas of Lycii Fructus.

Metabolomics coupled with similarity analysis advances the elucidation of the cold/hot properties of traditional Chinese medicines / 中国天然药物

It recently becomes an important and urgent mission for modern scientific research to identify and explain the theory of traditional Chinese medicine (TCM), which has been utilized in China for more than four millennia. Since few works have been contributed to understanding the TCM theory, the mechanism of actions of drugs with cold/hot properties remains unclear. In the present study, six kinds of typical herbs with cold or hot properties were orally administered into mice, and serum and liver samples were analyzed using an untargeted nuclear magnetic resonance (NMR) based metabolomics approach coupled with similarity analysis. This approach was performed to identify and quantify changes in metabolic pathways to elucidate drug actions on the treated mice. Our results showed that those drugs with same property exerted similar effects on the metabolic alterations in mouse serum and liver samples, while drugs with different property showed different effects. The effects of herbal medicines with cold/hot properties were exerted by regulating the pathways linked to glycometabolism, lipid metabolism, amino acids metabolism and other metabolic pathways. The results elucidated the differences and similarities of drugs with cold/hot properties, providing useful information on the explanation of medicinal properties of these TCMs.

1H NMR fingerprints of Huangqi injection solution / 药学学报

The study established the 1H NMR-based fingerprinting and analyzed 8 batches of Huangqi injection solution. 1H NMR-based fingerprinting of both primary and secondary metabolites of Huangqi injection were established, and the 1H-1H chemical shift correlation spectroscopy (COSY) and 1H-13C chemical shift correlation spectroscopy (HSQC) were used to identify the chemical components in Huangqi injection solution. Coupled with similarity analysis and relative content determination, 8 batches of Huangqi injection solution were analyzed. Twenty-five metabolites (both primary and secondary) were identified, and the significant differences were found in the chemical composition among these Huangqi samples. The content and content variation of the primary metabolites were much higher than those of the secondary metabolites, which was the major cause of the uniformity of the Huangqi injections. The results on the quality variations of Huangqi injections in this study will serve as a basis for improving the quality control.