Synthesis of carbon quantum dots with iron and nitrogen from Passiflora edulis and their peroxidase-mimicking activity for colorimetric determination of uric acid.

Carbon quantum dots co-doped with iron and nitrogen (Fe@NCDs) were synthesized by using Passiflora edulis Sims (P. edulis) as a precursor. The Fe@NCDs exhibit outstanding peroxidase-mimetic activity owing to successful doping with iron resulting in a behavior similar to that of iron porphyrins. In the presence of H2O2, the Fe@NCDs catalyze the oxidation of the peroxidase substrate 3,3',5,5'-tetramethylbenzidine (TMB) with a color change from colorless to blue. The blue oxidation product has a characteristic absorption peaking at 652 nm. A colorimetric assay was worked out for uric acid (UA) that measures the hydrogen peroxide produced during oxidation of UA by uricase. Response is linear in the 2-150 µM UA concentration range, and the limit of detection is 0.64 µM. The method was applied to the determination of UA in (spiked) urine, and recoveries ranged from 92.0 to 103.4%. Graphical abstract Schematic representation of the fabrication of iron and nitrogen co-doped carbon dots (Fe@NCDs) using Passiflora edulis Sims as carbon-based materials. First, uric acid (UA) was oxidized to generate H2O2 by uricase. Then, the Fe@NCDs catalyzed the oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) to form blue-colored oxidized TMB (oxTMB) in the presence of H2O2. UA can be quantified based on the theory.

Sleep disturbances among Chinese clinical nurses in general hospitals and its influencing factors.

BACKGROUND: This study aimed to determine the prevalence of sleep disturbances among clinical nurses in general hospitals in Mainland China, and identify its associate factors. METHODS: Using a cross-sectional design, a total of 5012 clinical nurses selected by random cluster sampling completed the survey on the Pittsburgh Sleep Quality Index (PSQI), measures of quality of life indexed by the Medical Outcomes Study 12-item Short-Form Health Survey, occupational stress evaluated by the Job Content Questionnaire, lifestyle and sociodemographic details. RESULTS: The average PSQI score of 4951 subjects was 7.32 ± 3.24, including 3163 subjects with PSQI ≥5, accounting for 63.9%. Multivariate Logistic regression analysis showed that the risk factors for sleep disturbances in nurses were female gender, the Emergency department and ICU, many years of service, high night shift frequency, professional status: primary and intermediate, employment status: temporary, poor quality of life: poor mental health, low perceived health, high occupational stress (high psychological demand, low job control and low workplace social support). CONCLUSIONS: Sleep disturbances are highly prevalent among clinical nurses in general hospitals in Mainland China. Many of the factors listed above were associated with the prevalence of sleep disturbances in nurses, and occupational stress plays an important role in the development of sleep disturbances in Chinese clinical nurses.