Nitrogen-doped carbon nanoparticles (N-CNPs) with a fluorescence quantum yield of 15.1％ were prepared from sucrose and urea in oleic acid medium by a one-pot solvothermal method.A new approach for quick,sensitive,and selective determination of free chlorine in water was developed based on fluorescence quenching of N-CNPs.There existed a good linear correlation between the fluorescence quenching and the concentration of ClO-in the range of 0.05-25.00 μmol/L.The limit of detection (LOD,S/N =3) was estimated to be 23 nmol/L.This method can be applied to the determination of free chlorine in real water samples.

BACKGROUND:Although vitamin C has an anti-oxidation role and can promote cell proliferation, there is a lack of research about the promoting effect of vitamin C on the proliferation of adipose-derived stem cells under high glucose conditions and the related molecular mechanisms.OBJECTIVE:To explore the promoting effect of vitamin C on the proliferation adipose-derived stem cells treated by the high glucose and the related molecular mechanisms.METHODS:Passage 3 human adipose-derived stem cells were cultured under high glucose conditions and then treated with different concentrations of vitamin C (0, 100, 150, 200, 250, 300 μmol/L). Cells cultured under low glucose conditions acted as controls. The expression levels of p-ERK and p-AKT proteins were detected by western blot. MTT method was used to choose the optimal concentration and time of vitamin C for all the subsequent tests. Human adipose-derived stem cells cultured under high glucose conditions were divided into four groups, and cells in blank control group had no treatment. Cells in the other three groups were treated with the optimal concentration of vitamin C (vitamin C group), LY294002+the optimal concentration of vitamin C (LY294002 group), or U0126+the optimal concentration of vitamin C (U0126 group) for 48 hours.EdU staining assay was used to detect the cell proliferation of human adipose-derived stem cells.RESULTS AND CONCLUSION:(1) Cell counting kit detection:We found that high glucose reduced the proliferation of human adipose-derived stem cells, and vitamin C promoted the proliferation of these cells. The best concentration of vitamin C was 200 μmol/L and the optimal effect time was 48 hours. (2) Western blot detection:Compared with the 0 μmol/L vitamin C group, the level of p-ERK in the 200 μmol/L vitamin C group was upregulated significantly (P < 0.01),while no significant expression change in p-AKT protein was found in control, 0 and 200 μmol/L vitamin C groups.(3) EdU test:the number of EdU positive cells was significantly higher in the vitamin C, LY294002, and control groups compared with the blank control group (P < 0.01). Moreover, compared with the vitamin C group, the EdU positive cells in the U0126 group were decreased significantly in number (P < 0.01). In conclusion, the ERK/MAPK signaling pathway is involved in the promotion effect of vitamin C on the proliferation of human adipose-derived stem cells under high glucose conditions.

Objective: To investigate the role of epidemiological history in the screening of Corona Virus Disease 2019 (COVID-19) in fever clinic, to improve the efficiency in fever clinic and reduce the incidence of cross infection. Methods: This is a retrospective study. Patients who were admitted to the fever clinic in West China Hospital of Sichuan University from January 23^th, 2020 to February 11^th, 2020 included the study. According to epidemiological history, the patients were divided into epidemiological history group (the experimental group) and no epidemiological history group (the control group). The two groups of patients were admitted and treated separately. The clinical data, NEWS score, etiology results, viral pneumonia showed on CT, time of visit, COVID-19 patient ratio, and admission composition ratio were compared between the two groups. The measurement data were presented as the mean ± standard deviation (SD), and the numeration data were expressed as ratio or constituent ratio. The measurement data of normal distribution between the two groups were compared by independent sample t test. The measurement data of skewed distribution are expressed by the median (interquartile range), and the comparison between the two groups is tested by non-parameter. The differences between enumeration data were assessed by chi-square test. A P<0.05 was considered statistically significant. Results: A total of 2423 patients were included, including 927 patients in the experimental group and 1296 patients in the control group. There were no significant differences in gender, NEWS score and clinical symptoms between the two groups (P> 0.05). The age (35.00 ± 12.80 vs 38.13 ± 15.57 years) , the proportion of fever patients (28.80% vs 32.75%) and waiting time (31.72 vs 58.08 min) of the experimental group were lower than the control group, the difference was statistically significant (P <0.05). The CT examination ratio (37.54% vs 20.39%), viral pneumonia ratio showed on CT (9.77% vs 2.95%), ratio of examined COVID-19 nucleic acid test (85.44% vs 56.75%), and the admission ratio (16.72% vs 9.63%) of the experimental group were higher than the control group, and the differences were statistically significant (P <0.05); There was no significant difference in the positive rates of influenza virus and rhinovirus between the two groups (P> 0.05). Conclusion It is necessary to adjust the management mode of fever clinic during the Corona Virus Disease 2019, and to manage the patients according to the epidemiological history which can improve the screening efficiency and reduce the risk of cross infection.