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Objective To observe the impact of coal-burning-borne fluorosis on the opening day of vagina,and estrogen cycle and endocrinology of female rat.Methods Ninety weaned two weeks and healthy female SD rats,weighing 60-80 g were selected,and divided into three groups by body weight using random number table:control group,moderate fluoride exposed group,and higher fluoride exposed group,thirty rates in each group.Rats in fluoride exposed groups were fed with baked corn collected from coal-burning-borne fluorosis areas containing different levels of fluorine(fluorine contents were 47.8 and 96.0 mg/kg,respectively) to establish coal-burning-borne fluorosis models.The corn fed to control group rats were collected from non-endemic areas (fluoride content was 5.2 mg/kg).After exposed to fluoride for 60,120 and 180 days,the rats were put to death during estrus in three batches (10 rats in every batche).The situation of female vaginal opening was observed and recorded every morning at 8:00 at the beginning of the experiment.Ten female rats in each group were randomly selected to observe vaginal exfoliated cells for 10 days continuously every morning,and HE staining was selected to discriminate estrogen cycle.Femoral artery blood was collected to observe the impact of estradiol(E2) in estrus.Results The vaginal opening day age of the longer fluoride exposed group [(49.0 ± 4.5)d] was longer than that of the control group[(45.4 ± 2.3)d] and the moderate fluoride exposed group[(46.7 ± 1.9)d,all P ＜ 0.05].Estrogen cycle of the longer fluoride exposed group[(5.8 ± 0.8)d] after fluoride exposure for 120 d was higher than that of the control group [(4.4 + 0.9)d] and the moderate fluoride exposed group [(4.9 ± 0.7)d,all P ＜ 0.05].Estrogen cycle increased with increasing dosage of fluoride after fluoride exposure for 180 d in three groups [control group:(4.3 ± 0.7)d,moderate fluoride exposed group:(5.4 ± 1.1)d,higher fluoride exposed group:(6.7 + 0.9)d,all P ＜ 0.05].Estrogen cycle in higher fluoride exposed group at 180 d[(6.7 ± 0.9)d] was higher than that of 60 d and 120 d[(5.2 ± 1.1),(5.8 ± 0.8)d,all P ＜ 0.05].At 60 d after exposed to fluoride,E2 levels of fluoride exposed groups were increased[control group:(30.125 ± 94.17)ng/L,moderate fluoride exposed group:(438.75 ± 71.80) ng/L],higher fluoride exposed group (456.25 ± 57.80)ng/L with increasing dosage of fluoride (all P ＜ 0.05).E2 level in rats exposed to fluoride for 180 d [(275.00 ± 127.83)ng/L] was lower than that of 60 d and 120 d [(456.25 ± 57.80),(392.50 ± 102.50)ng/L,all P ＜ 0.05] in higher fluoride exposed groups.Conclusions Coal-burning-borne fluorosis has a significant effect on vaginal opening day age,estrogen cycle and endocrinology of female rats.The higher the fluoride dose,and the longer the exposure time,the more severe the impact.
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In the paper, the optimal self-scaling strategy to the modified symmetric rank one (HSR1) update, which satisfies the modified quasi-Newton equation, is derived to improve the condition number of the updates. The scaling factors are derived from minimizing the estimate of upper bounds on the condition number of the updating matrix. Theoretical analysis, and numerical experiments and comparisons show that introducing the optimal scaling factor into the modified symmetric rank one update preserves the positive definiteness of updates, and greatly improves the stability and numerical performance of the modified symmetric rank one algorithm.