Green synthesis of luminescent graphitic carbon nitride quantum dots from human urine and its bioimaging application.

A hydrothermal synthetic approach is developed for the preparation of graphitic carbon nitride quantum dots (g-C3N4 QDs) from human urine. The reported synthetic method is green, simple, low-cost, less time-consuming, and can be used for the large-scale production of the g-C3N4 QDs. The as-prepared g-C3N4 QDs possess a high quantum yield of 15.7% by using quinine sulfate as a reference, and display excitation-wavelength dependent fluorescent emission. In addition, the g-C3N4 QDs exhibit high photostability, low cytotoxicity. and are successfully used as fluorescent probes for cell multicolor imaging. It is believed that the valuable nanomaterials, g-C3N4 QDs, which are transformed from the human bodily wastes, are promising in diverse chemical applications.

[Improved nitric acid digestion method for detecting diatom in autopsy tissue].

OBJECTIVE: To investigate the advantages of nitric acid digestion method and its differences with the traditional method. METHODS: Ethanol was used to fully fix the testing sample. About 80-100 g of the testing samples were cut into pieces and digested with nitric acid. It was then centrifuged and washed to remove organic components. Smears were prepared and examined under the light microscope. RESULTS: The diatom had been identified with clear striations, counted conveniently and classified easily. CONCLUSION: The improved nitric acid digestion method is not only simple with a higher successful rate of detection, but also can prevent interference from contamination. It can improve the stability of the experimental results, avoid harm to human and environment, and provide higher safety in the course of experiment.