ObjectiveTo understand the seropositivity of neutralizing antibodies (NAb) and low-level NAb against SARS-CoV-2 infection in the community residents, and to explore the impact of COVID-19 vaccination and SARS-CoV-2 infection on the levels of NAb in human serum. MethodsOn the ground of surveillance cohort for acute infectious diseases in community populations in Shanghai, a proportional stratified sampling method was used to enroll the subjects at a 20% proportion for each age group (0‒14, 15‒24, 25‒59, and ≥60 years old). Blood samples collection and serum SARS-CoV-2 NAb concentration testing were conducted from March to April 2023. Low-level NAb were defined as below the 25^th percentile of NAb. ResultsA total of 2 230 participants were included, the positive rate of NAb was 97.58%, and the proportion of low-level NAb was 25.02% (558/2 230). Multivariate logistic regression analysis indicated that age, infection history and vaccination status were correlated with low-level NAb (all P<0.05). Individuals aged 60 years and above had the highest risk of low-level NAb. There was a statistically significant interaction between booster vaccination and one single infection (aOR=0.38, 95%CI: 0.19‒0.77). Compared to individuals without vaccination, among individuals infected with SARS-CoV-2 once, both primary immunization (aOR=0.23, 95%CI: 0.16‒0.35) and booster immunization (aOR=0.12, 95%CI: 0.08‒0.17) significantly reduced the risk of low-level NAb; among individuals without infections, only booster immunization (aOR=0.28, 95%CI: 0.14‒0.52) showed a negative correlation with the risk of low-level NAb. ConclusionsThe population aged 60 and above had the highest risk of low-level NAb. Regardless of infection history, a booster immunization could reduce the risk of low-level NAb. It is recommended that eligible individuals , especially the elderly, should get vaccinated in a timely manner to exert the protective role of NAb.

Objective: To understand trends and related factors influencing overweight and obesity among primary and secondary school students in Tianjin, so as to provide a basis for formulating overweight and obesity prevention and control strategies. Methods: In September of each year from 2019 to 2023, a survey was conducted among 197 707 primary and secondary school students in 16 districts of Tianjin through a stratified random cluster sampling method. Physical examination was carried out in accordance with the Technical Standard for Physical examination for Student, and overweight and obesity survey was carried out. Basic information, smoking, drinking, diet, physical exercise, and sleep status were collected through questionnaire surveys. Results: The detection rates of overweight and obesity among primary and secondary school students in Tianjin from 2019 to 2023 were 39.07%, 43.33%, 41.54%, 43.92%, and 40.24%, respectively，showing an increasing trend(χ2trend=7.96,P<0.01). The detection rates of overweight increased in both vocational high schools and suburban counties (χ2trends=9.08, 47.18, P<0.01). The detection rates of obesity increased among both male and female students, in primary and vocational high schools and suburban counties (χ2trends=108.34, 15.99, 7.32, 10.95, 14.75, P<0.01). Multivariate Logistic regression analysis showed that smoking, drinking, unhealthful diet, and lack of proper physical exercise had a higher risk of obesity among primary and secondary school students (OR=1.26, 1.13, 1.08, 1.21, P<0.05). Stratified analysis showed that the risk of obesity was higher among boys with unhealthful and moderate lifestyle habits, as well as primary school students with unhealthful lifestyle habits (OR=1.15, 1.11, 1.27, P<0.05). Boys, girls and primary school students with unhealthful lifestyle habits, girls and ordinary high school students with moderate lifestyle habits had higher risk of being overweight (OR=1.14, 1.32, 1.21, 1.18, 1.40, P<0.05). Conclusions The detection rates of overweight and obesity among primary and secondary school students in Tianjin shows an increasing trend. Comprehensive lifestyle should be implemented to better prevent and control the risk of overweight and obesity.

OBJECTIVE：To establish a method for the content determination of to tal flavonoids from Amomum tsao-ko ，and to optimize the purification technology by macroporous resin. METHODS ：The content of total flavonoids was measured by HPLC. The determination was performed on Eclipse Plus C 18 column with mobile phase consisted of acetonitrile- 1％ acetic acid solution （15∶85，V/V）at the flow rate of 0.8 mL/min. The column temperature was 40 ℃，and the detection wavelength was set at 256 nm. The sample size was 10 μL. Taking the adsorption and desorption performance as indexes，6 kinds of macroporous resins were screened out by static adsorption and desorption tests ；adsorption and desorption time were investigated by static adsorption and desorption kinetics tests. Using the content of total flavonoids （calculated by rutin ）as index ，with sample concentration ，sample pH，ethanol volume fraction and elution amount as factors ，based on single factor test ，orthogonal design was used to optimize the purification technology of total flavonoids from A. tsao-ko ，and validation test was performed. RESULTS ：The linear range of rutin were 0.028-0.281 mg/mL（r＝0.999 9）. The limit of quantification was 437.5 ng/mL and the limit of detection was 109.4 ng/mL. RSDs of precision ，stability and reproducibility tests were all lower than 2％；the recoveries were 96.24％-99.75％（RSD＜2％，n＝ 6）. The comprehensive capacity of adsorption and desorption of HPD 450 macroporous resin was the most suitable ，and the best static adsorption and desorption time both were 12 h. The optimal purification technology was 1.854 4 mg/mL ； ethanol elution was 8 times of the column volume. Vertificationtests show that after optimized ，the content of total flavonoids from A. tsao-ko increased from 22.556 7 mg/g to 57.728 2 mg/g. The purity of was 2.56 and stable for the content determination. Optimal purification technology is stable and feasible ，which is suitable for purifieation of total flavonoids from A. tsao-ko .

Objective To determine the fetal facial angles at 11 －38 weeks of gestation by three‐dimensional ultrasound ( 3DUS) and analyze the correlation between facial angles and gestational age( GA ) . Methods From 2013 April to 2014 February ,439 singleton fetuses ranged 11－38 weeks of gestation were enrolled in this study . T he details of mid‐sagittal plane of facial profile was confirmed with 3DUS . Four facial angels were measured in this plane ,including frontomaxillary facial angle ( FM F ) ,frontonasal angle ( FNA ) ,mandibulomaxillary facial angle( M M F) and maxilla‐nasion‐mandible angle( M NM ) . T he intra‐and interobserver reliability were calculated in first 30 cases ,intra‐class correlation coefficient( ICC) greater than 0 .75 indicated good reliability . Pearson′s correlation coefficient ( r ) ,curve estimation and polynomial regression models were used to evaluate the correlation of the fetal facial angles with GA . Results ICC of the same observer were 0 .968 ,0 .962 ,0 .974 and 0 .988 ,respectively . ICC of different observer were 0 .948 , 0 .905 ,0 .874 and 0 .889 ,respectively . T he fetal facial angles of FM F ,FNA ,M M F and M NM showed correlations with GA ( r ＝ －0 .369 ,0 .447 ,－0 .470 ,0 .386 ; all P ＝0 .000) . Using GA as the independent variable and the facial angles as the dependent variables , the best fit regressing equation was cubic polynomial :FM F＝135 .300－6 .473×GA+0 .235×GA2 －0 .003×GA3 ( R2 ＝0 .240 , P ＝0 .000 ) ;FNA＝58 .920+7 .452×GA －0 .274×GA2 －0 .003×GA3 ( R2 ＝0 .297 , P ＝0 .000 ) ;M M F＝132 .329 －5 .337× GA+0 .191× GA2 －0 .002× GA3 ( R2 ＝ 0 .304 , P ＝ 0 .000) ;M NM ＝ －24 .592+ 4 .653× GA －0 .173× GA2 + 0 .002 × GA3 ( R2 ＝ 0 .413 , P ＝ 0 .000 ) . Conclusions The development of fetal facial angles are related to GA . T he growing patterns of fetal facial angles fit with a cubic polynomial function .

Objective To evaluate the fetal profile (FP) line with two-dimensional and three dimensional ultrasound, to explore the changes of fetal facial profile with gestational age,and to analyze the manifestation of FP line for abnormal chromosomal fetuses. Methods FP line, which was defined as the line that passes through the anterior border of mandible and the nasion, was test on the facial mid-sagittal plane. Firstly, from April 2013 to January 2014, FP line was analyzed in 439 normal fetuses of Peking Union Medical College Hospital at 11-38 weeks of gestation. According to the relationship between FP line and fetal frontal bone,it was divided into three types: the FP line passed anteriorly, across or posteriorly to the frontal bone, respectively. When the FP line passed posteriorly to the frontal bone, the distance (F distance) between the FP line with the frontal bone was measured. Secondly, 26 pathological fetuses (21 trisomy 21 fetuses with 13-33 weeks' gestation and 5 trisomy 18 fetuses with 21-31 weeks' gestation) were analyzed respectively. Results No cases with a FP line passed anteriorly to the frontal bone were found in all of normal fetuses. Most commonly seen was that FP line passed across to the frontal bone (92.26%). The FP line passed posteriorly to the frontal bone in up to 7.74%, and the mean F distance was 0.24 cm (range, 0.10-0.51 cm). In 21 fetuses of trisomy 21, 14 cases showed the FP line passed across to frontal bone, and 4 cases showed the FP line passed posteriorly frontal bone with the F distance from 0.23 cm to 0.55 cm. Three cases with sloping forehead with FP line passed anteriroly to frontal bone. As to 5 cases of trisomy 18, 2 cases showed FP line passed across to frontal bone, and 3 cases with micrognathia had FP line passed anteriroly to frontal bone. Conclusions No cases with a FP line passed anteriorly to the frontal bone were found in normal fetuses. The FP line, as a reference line for forehead and mandible abnormality, may be a useful tool to detect second trimester profile abnormalities such as sloping forehead and retrognathia.

Objective To investigate the incidence and distribution of fetal discrepancy during the first trimester in dichorionic twins.Methods This was a prospective analysis of dichorionic twin pregnancies that underwent 11+0～ 13+6 week scan at a tertiary hospital from Sep 2008 to Oct 2010.Differences in crown-rump length (CRL),nuchal translucency ( NT),heart rate ( HR).deepest vertical pockets of amniotic fluid (DVP) for every pair of twin fetuses were calculated and expressed as absolute value and percentage of discordance.Results A total of 66 dichorionic twin pregnancies were included.The average CRL was significantly different between the larger fetus and the smaller one,which were (65.28 ±8.54)mm and (62.34 ± 8.49) mm respectively ( P ＜ 0.001).The average NT was significantly different between two fetuses,which were ( 1.56 ± 0.35) mm and (1.28 ± 0.30) mm respectively. HR and DVP were also statistically different between two fetuses ( P ＜0.001).Conclusions The growth of two fetuses in normal dichorionic twins is not uniform during the first trimester.

Objective To investigate the diagnostic value of prenatal ultrasonography in the fetal hemivertebra. Methods The ultrasonographic findings of three fetuses with hemivertebra diagnosed in our hospital were reviewed and compared with those of postnatal ultrasonography,other image modalities,and autopsy. Results In all fetuses,a distortion of the spine was observed where only one half of the vertebra could be identified. The parents opted for termination of the pregnancy in one case and the deformity was confirmed by autopsy. The other two fetuses were delivered and in one fetus the diagnosis was confirmed by radiological assessment. Conclusions Hemivertebra can be diagnosed accurately by second-trimester ultrasonography. The prognosis is mostly favorable when no other anomalies are associated. Meticulous examination may disclose the lesion and help decide the fate of pregnancy.

ObjectiveTo evaluate the diagnostic capability of prenatal ultrasound in diagnosis of fetal akinesia deformation sequence (FADS).MethodsThe prenatal sonographic characteristics of 5 fetuses with FADS were analyzed retrospectively.ResultsBoth multiple joint contractures and central nervous system (CNS) anomalies,which include 5 small head circumferences,2 short cerebellar diameters,and 1 flat forehead,were found by prenatal ultrasound in all 5 FADS fetuses.Additional fetal abnormalities such as micrognathia,polyhydramnios,short umbilical cord and intrauterine growth retardation were also observed.The results of fetal chromosome analysis were available in 2 cases indicating normal karyotype.Conclusions Prenatal identification and diagnosis of FADS is possible based on the findings of sonographic examination.

Objective To investigate the diagnositic value of ultrasonography in fetuses with cystic biliary malformation. Methods Three cases of cystic biliary malformation diagnosed in our hospital by prenatal ultrasound were followed up until surgery after birth. Results In all three cases.an anechoic cystic lesion was detected in the right upper abdomen at 16,26,34 weeks' gestation respectively, which were diagnosed as biliary cystic malformation by prenatal ultrasound. Two cases were confirmed as choledochal cyst by surgery, one case as biliary atresia. The maximum diameter during pregnancy of choledochal cyst were 3. 9 cm and 4.2 cm respectively, which increased steadily as gestational age advanced, with normal gallbladder in continuity with the choledochal cyst. But the largest diameter of the cyst in congenital biliary atresia was 1.7 cm and remained unchanged throughout the remaining pregnancy, the gallbladder could not be detected or an irregular small gallbladder was shown. Excision of the cyst and Roux-en-Y hepaticojejunostomy were successfully performed in all three cases. Postoperative course were uneventful. Conclusions Cyst diameter, change in size, gallbladder ultrasound pattern may allow to make a prenatal differential diagnosis of biliary tree cystic malformation. Small and stable cyst with an undetected gallbladder or small gallbladder is more suggestive of biliary atresia than choledochal cyst. Precise imaging may facilitate prenatal counseling and perinatal management. The outcomes had improved with earlier operations.

Objective To determine the diagnostic value of two and three dimensional ultrasound in detecting fetal hand malformations. Methods In the retrospectively analysis,the severe fetal hand malformations detected by prenatal ultrasound during the recent three years in our hospital were classified according to the prenatal sonographic characteristics,family history,karyotype analysis and autopsy results,etc.Results Fourteen fetuses with hand-anomaly were detected during the 16-28th week of gestation,both hands were affected in 10 cases,with the same morphology bilaterally in 8 cases.Thirteen cases had other abnormal sonographic findings.They were detected and classified into three categories,Wrist deformity (9 cases),three fetuses were associated with total absence of radius and radial clubhand,and six fetuses had palmar deviated hands,with various etiologies including familial hereditary arthrogryposis multiplex congenita,distal type 1 (AMCD1),amniotic band syndrome,body stalk anomaly,trisomy18 and micromelia.Hand (figer) hypoplasia or aphasia (3 cases),one hand was absent in one fetus without associated anomaly,absence of five fingers with ipsilateral multicystic dysplastic kidney in the second fetus,and the third fetus had split hand/foot malformation (SHFM).Overlapping fingers (4 cases),three of them were trisomy18,and two fetuses had both wrist deformity and overlapping fingers.Conclusions Prenatal two and three dimensional ultrasound play an important role in detecting and diagnosing severe type of fetal hand malformations.