RESUMO
Objective@#To explore the association between different family factors and children’s puberty timing, and to provide a reference for further research on puberty development of children.@*Methods@#A prospective cohort study was conducted on a total of 1 237 children in one district, Chongqing, using targeted sampling. Cox regression was used to analyze the association between family factors and the puberty timing of children.@*Results@#The results of univariate analysis showed that baseline age and BMI were risk factors of early puberty timing in boys and girls (P<0.01). Breast development (HR=1.27, 95%CI=1.04-1.54) was observed earlier in vaginal delivery than in cesarean section. Self-conscious family economic condition is good is the protective factor for the early timing of girl’s menstruation (HR=0.81, 95%CI=0.66-0.99), pubic hair development(HR=0.80, 95%CI=0.65-0.97) and the boy’s puberty development (Testicular development HR=0.69, 95%CI=0.58-0.83, first ejaculation HR=0.62, 95%CI=0.49-0.78, external genitalia development HR=0.70, 95%CI=0.56-0.87, pubic hair development HR=0.66, 95%CI=0.54-0.80). The left-behind boys later observed testicular development (HR=0.74, 95%CI=0.57-0.96), first ejaculation (HR=0.71, 95%CI=0.50-0.99) and pubic hair development (HR=0.68, 95%CI=0.51-0.91). Testicular development (HR=1.26, 95%CI=1.01-1.58) was observed earlier in boys who felt their parents were close (P<0.05). The results of multivariate analysis showed that the timing of pubic hair development was later in floating girls (HR=0.79, 95%CI=0.65-0.96), and family factors had nothing to do with the puberty timing in boys.@*Conclusion@#In the study, left behind children, self-perceived of parents relationship and family economic conditions are the influencing factors of children’s puberty timing. However, after adjusted for age and BMI, this association was mainly found in pubic hair of girls. The association between family factors and other pubertal development events still needs to be confirmed by further follow-up investigation.
RESUMO
Coptis chinensis is widely used as Chinese medicine herbs and serious soil problems occur after continual cultivation of this medicinal plant. In the preset experiment, fibrous root extract of C. chinensis (REC) was added into soil to study the effect of REC on microbes and enzyme activity in soil. The results showed that both bacteria and actinomycetes decreased by about 2 times in contrast to fungi, which increased by about 3 folds. Phosphorus bacteria, potassium bacteria, azotobacter, ammonia bacteria, and nitrifying bacteria were also reduced significantly by REC, suggesting the inhibition of nitrogen biofixation and supply, mobilization of phosphorus and potassium, ad plant growth promotion as REC added into soil. There were multiple influences of REC on soil enzyme activities. Invertase activity was stimulated, while urease was inhibited and dehydrogenase unchanged by REC, indicating the interference of biochemical reactions in soil. In addition, type and total content of phosphorus lipid fatty acids (PLFAs) , the signature of microbes, decreased while the ratio of bacterium to fungus PLFAs increased as REC increased in soil, which suggested that fungi increased relatively with bacteria decreased thereby leading to easy occurrence of crop fungus diseases following cultivation of C. chinensis. The decrease in diversity and evenness indexes of microbial community in soil by REC indicated soil ecosystem deterioration and reduction of microbial groups and densities in soil. Therefore, allelopathic chemicals released from the roots of C. chinensis could change microbial community structure and resulted in serious soil problems by continual cropping of this medicinal plant.