Objective To investigate the relationship between risk factors and recurrent respiratory tract infections( RRTI) in children. Methods A case-control study was carried out in 204 children with RRTI,com-pared with 400 children without RRTI in control group. Results Second-hand smoking,breastfeeding,malnutri-tion,zinc deficiency,pet at home,home decoration and use of glucocorticoid were associated with RRTI in chil-dren. But the association between breastfeeding and RRTI was only found in children less than 5 years old. The second hand smoking was associated with RRTI only among boys,rather than girls. Home decoration,zinc defi-ciency,malnutrition and breastfeeding were associated with RRTI only among girls,but not among boys. Conclu-sion Recurrent respiratory tract infections are associated with multiple factors. Different risk factors have differ-ent affections on RRTI on gender.

Objective To investigate whether maternal antibody to hepatitis B surface antigen (anti-HBs)in infants may interfere with the antibody response to hepatitis B vaccine. Methods Infants from singleton pregnant mothers,who delivered at full term at the Affiliated Drum Tower Hospital of Nanjing University Medical School from October 2006 to January 2007,were divided into two groups based on their mothers'status of anti-HBs(43 positive and 29 negative).All infants were vaccinated with hepatitis B vaccine at birth and one month thereafter.Serum anti-HBs were quantitatively determined for the mothers before delivery and for infants in cord blood at delivery and in serum at the age of 1 and 3.5 months. Results Anti-HBs of all 43 newborns in the positive group were positive in cord blood with the coefficiency of 0.98 to the maternal serum anti-HBs level(t=39.05,P<0.01).Forty-two out of the 43 infants remained anti-HBs positive at the age of 1 month.Anti-HBs was negative both at birth and 1 month old in infants of the negative group.However,all infants in both groups were anti-HBs positive at 3.5 months of age,while the average concentration of anti-HBs in infants of the negative group was significantly higher than that of the positive group [(466.9±86.7)mIU/ml vs(151.2±23.1)mIU/ml,t=2.72,P=0.011].Among the 5 infants whose maternal anti-HBs level>1000 mIU/ml,3 did not produce active antibodies against two doses of hepatitis B vaccination. Conclusions Passively acquired maternal anti-HBs in infants can inhibit the active antibody response to hepatitis B vaccine,and the extent of this effect is associated with maternal anti-HBs level.

Objective:To develop an artificial intelligence (AI) quality control model of fetal heart in the first trimester and verify its effectiveness.Methods:A total of 18 694 images of the four-chamber view(4CV) and three-vessel and tracheal view(3VT) of fetal heart in the first trimester were selected from Shenzhen Maternal and Child Health Hospital Affiliated to Southern Medical University since January 2022 to December 2022. A total of 14 432 images were manually annotated. The one-stage target detection algorithm YOLO V5 was used to train the AI quality control model in the first trimester of fetal heart, and 4 262 images (golden standard set by expert group) were used to evaluate the application effectiveness of AI quality control model. Kappa consistency test was used to compare the results of section classification and standard degree judgment from AI quality control model, Doctor 1(D1) and Doctor 2(D2).Results:①Precision of the AI quality control model was 0.895, recall was 0.852, mean average precision (mAP 50) was 0.873.The average precision(AP) of the AI quality control model for section classification was 0.907 (4CV) and 0.989 (3VT), respectively. ②Compared with the gold standard, the overall coincidence rate and consistency of section classification of AI quality control model, D1 and D2 were 99.91% (Kappa=0.998), 100% (Kappa=1.000), 100% (Kappa=1.000), respectively. The coincidence rate and consistency of the plane standard degree evaluation from the AI quality control model, D1 and D2 were 97.46% (Weighted Kappa=0.932), 93.73% (Weighted Kappa=0.847), and 93.12% (Weighted Kappa=0.832), respectively. Strong consistency was displayed. Moreover, AI quality control model showed the highest coincidence rate and the strongest consistency in judging section standard degree, which was superior to manual quality control. The time-consuming of AI quality control (0.012 s/sheet) was significantly less than the way of manual quality control (4.76-6.11 s/sheet)( Z=-8.079, P<0.001). Conclusions:The use of artificial intelligent fetal heart quality control model in the first trimester can effectively and accurately control the image quality.

Objective To observe the correlations of pontine biological indicators on fetal brain median sagittal MRI with gestational week.Methods Data of head MRI of 226 normal fetuses without obvious abnormalities of central nervous system(normal group)and 17 fetuses with abnormalities(abnormal group)at gestational age of 23 to 38 weeks were retrospectively analyzed.Pontine biological indicators based on median sagittal MRI were obtained,including pons anteroposterior diameter(PAD),total pons area(TPA),pontine basal anteroposterior length(AP),pontine basal cranio-caudal length(CC),basis pontis area(BPA)and pontine angle of midbrain(MAP).According to the gestational week,the fetuses of normal group were divided into 8 subgroups.The distributing ranges of pontine biological indicators at different gestational weeks were analyzed,and the correlations of pontine biological indicators with gestational week in normal group were explored,and the developmental status of fetal pons in abnormal group were assessed.Results In normal group,PAD,TPA,AP,CC and BPA all showed linear positive correlation(r=0.887,0.914,0.787,0.866,0.865,all P＜0.001),while MAP was not significantly correlated with gestational week(P＞0.05).Among 17 fetuses in abnormal group,abnormal PAD or TPA was found each in 8 fetuses,abnormal AP was observed in 14,abnormal CC was noticed in 3 and abnormal BPA was found in 11 fetuses.Conclusion Fetal pontine biological indicators such as PAD,TPA,AP,CC and BPA on median sagittal MRI were positively correlated with gestational week,hence being able to be used for evaluating fetal pontine development.