RESUMEN
Hypochlorite (ClO-) has received extensive attention owing to its significant roles in the immune defense and pathogenesis of numerous diseases. However, excessive or misplaced production of ClO- may pose certain diseases. Thus, to determine its biological functions in depth, ClO- should be tested in biosystems. In this study, a facile, one-pot synthesis of nitrogen-fluorine-doped carbon quantum dots (N, F-CDs) was developed using ammonium citrate tribasic, L-alanine, and ammonium fluoride as raw materials under hydrothermal conditions. The prepared N, F-CDs demonstrate not only strong blue fluorescence emission with a high fluorescence quantum yield (26.3%) but also a small particle size of approximately 2.9 nm, as well as excellent water solubility and biocompatibility. Meanwhile, the as-prepared N, F-CDs exhibit good performance in the highly selective and sensitive detection of ClO-. Thus, a wide concentration response range of 0-600 µM with a low limit of detection (0.75 µM) was favorably obtained for the N, F-CDs. Based on the excellent fluorescence stability, excellent water solubility, and low cell toxicity, the practicality and viability of the fluorescent composites were also successfully verified via detecting ClO- in water samples and living RAW 264.7 cells. The proposed probe is expected to provide a new approach for detecting ClO- in other organelles.
RESUMEN
By using the observation data from 620 meteorological stations in China, the annual accumulated temperature above 10 degrees C, its starting date, ending date, and duration days from 1951 to 1978 and from 1979 to 2005 were calculated and compared. The results showed that in most areas of China, especially in Northeastern, North, and South China, the accumulated temperature above 10 C from 1979 to 2005 was higher than that from 1951 to 1978. The starting date of accumulated temperature above 10 degrees C in northern areas of Yangtze River was 0-5 days earlier from 1979 to 2005 than from 1951 to 1979, while that in southern areas of Yangtze River was 0-5 days later from 1979 to 2005 than from 1951 to 1979. The ending date of accumulated temperature above 10 degrees C in most areas of China was delayed 0-5 days, except that in near coastal areas of South China and some regions of Southwest China, which was delayed more than 5 days. The duration days of accumulated temperature above 10 C were generally increased by 0-5 days or 5-10 days in most areas of China, but the increase amplitude was different and could not be linked together in different areas. To accurately know the changing trend of accumulated temperature above 10 degrees C could provide an important basis for the adjustment of agricultural production structure and the assessment of agricultural potential productivity.