ABSTRACT
Objective To investigate the levels of trace elements in preschool children in Guangzhou and their relationships with nutritional status, and to provide a scientific basis for guiding children's nutritional diet and timely and reasonable supplementation of trace elements. Methods A cross-sectional study was used to perform physical examinations and collect blood samples from 5 002 children who were examined in the Department of Pediatric Health of a Maternal and Child Health Hospital in Guangzhou in 2018. The levels of trace elements including iron, zinc and copper were detected by atomic absorption spectrometer. Results The median (upper and lower quartile) levels of iron, zinc and copper for preschool children in a district of Guangzhou were 7.80 (7.39, 8.19) mmol / L, 69.0 (61.0, 76.5) μmol / L, 18.6 (15.9, 21.4) μmol / L. There was no significant difference in the levels of iron, zinc and copper between different genders (P>0.05). The levels of iron and zinc increased significantly with the age of children (P=0.000). There was no significant difference in the level of copper in different ages (P>0.05). The prevalence rates of iron, zinc and copper deficiency in preschool children were 14.93%, 21.93% and 0.24%, respectively, and there was no significant difference between different genders (P>0.05).There were no significant differences in the prevalence of iron and copper deficiency in different ages (P>0.05), while the zinc deficiency rate decreased with the age of children (P = 0.000). (P0.05). The prevalence rates of iron and zinc deficiency in children with malnutrition, overweight and obesity were higher than those in normal children. There was no significant difference in the prevalence of copper deficiency in children with different nutritional status (P>0.05). Conclusion The prevalence of iron, zinc deficiency is high in preschool children in Guangzhou. Preschool children with malnutrition, overweight and obesity are more prone to iron and zinc deficiency.
ABSTRACT
Agriculture is an important source of greenhouse gases, but can also be a significant sink. Nitrogen fertilization is effective in increasing agricultural production and carbon storage. We explored the effects of different rates of nitrogen fertilization on biomass, carbon density, and carbon sequestration in fields under the cultivation of Jerusalem artichoke as well as in soil in a coastal saline zone for two years. Five nitrogen fertilization rates were tested (in guream(-2)): 4 (N1), 8 (N2), 12 (N3), 16 (N4), and 0 (control, CK). The biomass of different organs of Jerusalem artichoke during the growth cycle was significantly higher in N2 than the other treatments. Under different nitrogen treatments, carbon density in organs of Jerusalem artichoke ranged from 336 to 419gCkg(-1). Carbon sequestration in Jerusalem artichoke was higher in treatments with nitrogen fertilization compared to the CK treatment. The highest carbon sequestration was found in the N2 treatment. Soil carbon content was higher in the 0-10cm than 10-20cm layer, with nitrogen fertilization increasing carbon content in both soil layers. The highest soil carbon sequestration was measured in the N2 treatment. Carbon sequestration in both soil and Jerusalem artichoke residue was increased by nitrogen fertilization depending on the rates in the coastal saline zone studied.
