[Secular trends of age at menarche and age at menopause in women born since 1951 from a county of Shandong Province, China].

OBJECTIVE: To describe the secular trends of age at menarche and age at natural menopause of women from a county of Shandong Province. METHODS: Based on the data of the Premarital Medical Examination and the Cervical Cancer and Breast Cancer Screening of the county, the secular trends of age at menarche in women born in 1951 to 1998 and age at menopause in women born in 1951 to 1975 were studied. Joinpoint regression was used to identify potential inflection points regarding the trend of age at menarche. Average hazard ratios (AHR) of early menopause among women born in different generations were estimated by performing multivariate weighted Cox regression. RESULTS: The average age at menarche was (16.43±1.89) years for women born in 1951 and (13.99±1.22) years for women born in 1998. The average age at menarche was lower for urban women than that for rural women, and the higher the education level, the lower the average age at menarche. Joinpoint regression analysis identified three inflection points: 1959, 1973 and 1993. The average age at menarche decreased annually by 0.03 (P < 0.001), 0.08 (P < 0.001), and 0.03 (P < 0.001) years respectively for women born during 1951-1959, 1960-1973, and 1974-1993, while it remained stable for those born during 1994-1998 (P=0.968). As for age at menopause, compared with women born during 1951-1960, those born during 1961-1965, 1966-1970 and 1971-1975 showed a gradual decrease in the risk of early menopause and a tendency to delay the age at menopause. The stratified analysis presented that the risk of early menopause gradually decreased and the age of menopause showed a significant delay among those with education level of junior high school and below, but this trend was not obvious among those with education level of senior high school and above, where the risk of early menopause decreased and then increased among those with education level of college and above, and the corresponding AHRs were 0.90 (0.66-1.22), 1.07 (0.79-1.44) and 1.14 (0.79-1.66). CONCLUSION: The age at menarche for women born since 1951 gradually declined until 1994 and leveled off, with a decrease of nearly 2.5 years in these years. The age at menopause for women born between 1951 and 1975 was generally delayed over time, but the trend of first increase and then decrease was observed among those with relatively higher education levels. In the context of the increasing delay in age at marriage and childbearing and the decline of fertility, this study highlights the necessity of the assessment and monitoring of women' s basic reproductive health status, especially the risk of early menopause.

[Association between HULC gene locus rs7763881 polymorphism and recurrence and metastasis after radical resection in hepatocellular carcinoma].

Objective: To investigate the association between the expression of long non-coding RNA genes and the HULC rs7763881 polymorphism, recurrence, and metastasis after radical resection in patients with hepatocellular carcinoma (HCC). Methods: Paraffin tissue samples were selected from 426 cases diagnosed with HCC between January 2004 to January 2012. The expression of different genotypes of HULC gene locus rs7763881 in paraffin tissues was detected by PCR, and the association between different genotype expressions and clinical case characteristics of HCC [gender, age, TNM stage, alpha-fetoprotein, tumor maximum diameter (cm), vascular invasion, tumor capsule, tumor grade] was analyzed. Cox proportional risk regression model was used to analyze the correlation between different genotypes and clinicopathological features, prognosis, and recurrence. Survival analysis between different genotypes was performed using the Kaplan-Meier method for a parallel log-rank test. Results: There were 27 (6.3%) cases in the whole group who lost to follow-up. A total of 399 (93.7%) specimens were included in the study, and 105 (26.3%), 211 (52.9%) and 83 (20.8%) were included in the rs77638881 AA, AC, and CC genotypes, respectively. Kaplan-Meier curve showed that the postoperative overall survival and recurrence-free survival rate were significantly higher in patients with the AA than AC/CC genotype (P < 0.05). Univariate analysis showed that the AC/CC genotype was closely related to tumor vascular invasion and recurrence or metastasis of HCC (P < 0.05). Cox multivariate analysis results showed that patients with the AA genotype were taken as references, and the results showed that the risk of recurrence and metastasis in patients with the CA/CC genotype increased to varying degrees, with statistical significance (P < 0.05). Conclusion: The rs7763881 polymorphic loci located on the HULC gene are closely related to HCC recurrence and metastasis after radical resection. Thus, it may be an indicator for evaluating HCC recurrence and metastasis.

[Correlation between intrahepatic triglyceride content quantified by proton magnetic resonance spectroscopy and glucose metabolism].

Objective: To investigate the correlation between intrahepatic triglyceride content (IHTC) and glucose metabolism in patients with non-alcoholic fatty liver disease (NAFLD) diagnosed by proton magnetic resonance spectroscopy (1H-MRS). Methods: A total of 239 subjects without diabetes mellitus were previously enrolled and underwent 1H-MRS scans. Anthropometric indexes including height, weight, waist and blood pressure, and laboratory findings as plasma glucose (PG), insulin (INS), C-peptide (CP), liver enzymes [alanine aminotransferase (ALT), aspartate transaminase (AST), γ-glutamyl transpeptidase (GGT)] and lipid profiles were collected. According to IHTC levels, participants were divided into three groups: the non-NAFLD group (IHTC<5.56%), the mild NAFLD group (IHTC 5.56%-<33%), and the moderate and severe NAFLD group (IHTC ≥ 33%). The clinical characteristics of each group were analyzed, and the correlation between IHTC and glucose metabolism were assessed. Results: Compared with those in the non-NAFLD group, male proportion, waist, 120 min postprandial PG (PG120), CP, liver enzymes and total cholesterol (TC) levels were greater in the NAFLD group, whereas insulin sensitivity index-Cederholm (ISI-Cederholm) and high density lipoprotein cholesterol (HDL-C) levels were lower in the NAFLD groups. Subjects in the moderate and severe NAFLD group had higher levels of 120 min postprandial INS (INS120) and Stumvoll indexes, and lower ISI-Cederholm than those in the mild NAFLD group [80.37 (57.68, 112.70) mU/L vs.110.50(71.78, 172.80)mU/L, 1453(1178, 1798)vs.1737(1325, 2380), 358(297, 446) vs.441(318, 594), 2.27(2.01, 2.53) vs.2.06(1.81, 2.39), respectively, all P<0.05]. Correlation analyses showed that IHTC was significantly positively correlated with waist hip ratio (WHR), PG120, INS120, HOMA insulin resistance (HOMA-IR), Stumvoll 1st-insulin secretion, Stumvoll 2nd-insulin secretion, ALT, AST, GGT and TC (r=0.197, 0.274, 0.334, 0.162, 0.199, 0.211, 0.406, 0.361, 0.215, and 0.196, respectively, all P<0.05), and negatively correlated with ISI-Cederholm and HDL-C (r=-0.334, and-0.237, respectively, all P<0.05). Furthermore, a multiple linear stepwise regression analysis indicated that ISI-Cederholm (Standardized ß =-0.298, P<0.001) and Stumvoll 1st insulin secretion (Standardized ß = 0.164, P = 0.024) were independent factors of IHTC. Conclusions: Peripheral insulin resistance occurs in the early stage of NAFLD and becomes worse with the progression of the disease. IHTC was independently associated with insulin sensitivity and first-phase insulin secretion.

[Thyroid function of first-trimester twin pregnant women and its association with preterm delivery].

OBJECTIVE: To describe the thyroid function abnormality of first-trimester twin pregnant women according to different references, and to explore its association with preterm delivery. METHODS: Participants, first-trimester twin pregnant women, were recruited at Peking University Third Hospital from March 2017 to February 2020. The thyroid hormone reference for ordinary adults identified on the assay kits by Siemens incorporation, thyroid hormone reference specifically for singleton pregnancy established previously, and thyroid hormone reference specifically for twin pregnancy established previously were used in the description of hypothyroidism and hyperthyroidism for first-trimester twin pregnant women. Thyroid autoantibody reference identified on the assay kits by Siemens incorporation was used in the description of positive thyroid autoantibody. Multivariable log-binomial regression was conducted to examine the association between thyroid function and preterm delivery, in which normal pregnant women according to the three references and normal pregnant women according to twin pregnancy reference accompanied with negative thyroid autoantibody were taken as control respectively. RESULTS: A total of 570 twin pregnant women were finally included. Rates of hypothyroidism according to the three references were 1.2%, 1.6% and 3.5%, respectively. Rates of hyperthyroidism according to the three references were 32.6%, 18.1% and 1.1%, respectively. After adjustment for potential confounding factors, risk of preterm delivery significantly increased in pregnant women with hyperthyroidism according to the twin specific pregnancy reference [adjusted relative risk (ARR)=1.41, 95%CI: 1.14-1.75], while no significant increase was found in those with normal thyroid function according to the twin specific pregnancy reference but hyperthyroidism according to the singleton specific pregnancy reference (ARR=1.00, 95%CI: 0.81-1.25) and in those with hyperthyroidism purely according to the ordinary adult reference (ARR=1.06, 95%CI: 0.85-1.32), compared with those normal according to all the references. Risks of preterm delivery almost significantly or significantly increased in pregnant women with hypothyroidism according to the ordinary adult or singleton specific pregnancy reference (ARR=1.40, 95%CI: 0.88-2.22) and those with hypothyroidism according to the twin specific pregnancy reference (ARR=1.53, 95%CI: 1.03-2.28). Overall analysis of thyroid function according to the twin specific pregnancy reference and thyroid autoantibody showed that risks of preterm delivery almost significantly or significantly increased in pregnant women with simple hypothyroidism (ARR=1.46, 95%CI: 0.93-2.27), simple positive thyroid autoantibody (ARR=1.32, 95%CI: 1.15-1.52), and hypothyroidism accompanied with positive thyroid autoantibody (ARR=1.78, 95%CI: 1.30-2.44), compared with those normal according to the twin specific pregnancy reference with negative thyroid autoantibody. CONCLUSION: The ordinary adult reference and that of singleton pregnancy may lead to under-diagnosis of hypothyroidism and over-diagnosis of hyperthyroidism in first-trimester twin pregnant women. Compared with pregnant women with normal thyroid function, those missed in the diagnosis of hypothyroidism were at a higher risk of preterm delivery, while those over-diagnosed as hyperthyroidism had a similar risk of preterm delivery, indicating a need to develop and generalize twin-pregnancy-specific reference on common indicators of thyroid function. Moreover, the thyroid autoantibody should be taken into consideration in the prenatal diagnosis and treatment to twin pregnant women with hypothyroidism.

Dynamic characteristics of AHLs-secreting strain Aeromonas sp. A-L2 and its bioaugmentation during quinoline biodegradation.

AIMS: In order to probe a more environmentally friendly method of pollutant treatment based on microbial bioaugmentation and quorum sensing (QS) effects. METHODS AND RESULTS: The dynamic characteristics and QS effects of the acylated homoserine lactones (AHLs)-secreting strain Aeromonas sp. A-L2 (A-L2), which was isolated from the activated sludge system, was discussed. According to the liquid chromatography-mass spectrometry results, N-butyryl-homoserine lactone (C4-HSL) and N-hexanoyl-homoserine lactone (C6-HSL) were the major AHLs secreted by strain A-L2, and the swarming of strain Ochrobactrum sp. LC-1 (LC-1) was induced by these compounds. The extracellular polymeric substance secretion of the strain LC-1 was mainly led by C6-HSL, and the biofilm formation ability was mainly influenced by C6-HSL or C4-HSL (60 µg l-1 ). The optimal AHLs secretion conditions of strain A-L2 were also studied. Drawing support from the AHLs-secreting strain A-L2 during quinoline degradation by strain LC-1, the degradation time was greatly shortened. CONCLUSIONS: Hence, AHLs-secreting strain A-L2 can be useful as an AHLs continuous supplier during bioaugmentation and pollutant biodegradation. SIGNIFICANCE AND IMPACT OF THE STUDY: The bioaugmentation process of strain A-L2 on quinoline biodegradation based on QS effects would lay a certain theoretical and practical significance for large-scale applications.

[Relationship of plasma vitamin A levels between neonates and pregnant women in third trimester].

OBJECTIVE: To study the correlation of plasma vitamin A (VitA) levels between neonates and pregnant women in third trimester. METHODS: A total of 688 pregnant women were recruited in Yuanshi and Laoting counties of Hebei Province, from May to June 2009. Venous blood samples of women before delivery and cord blood samples of newborns were collected and measured for retinol (retinol concentration was used to reflect VitA level) using high performance liquid chromatography assay. According to venous blood plasma retinol concentration, maternal VitA nutritional status was divided into deficiency (<0.70 µmol/L), marginal deficiency (0.70-<1.05 µmol/L), and sufficiency (≥1.05 µmol/L). According to cord blood plasma retinol concentration, neonatal VitA nutritional status was divided into deficiency (<0.35 µmol/L), marginal deficiency (0.35-<0.70 µmol/L), and sufficiency (≥0.70 µmol/L); neonatal VitA relative deficiency was further defined as cord blood plasma retinol concentration lower than the 10th percentile. VitA placental transport ratio was defined as retinol concentration in the neonates divided by that in pregnant women. Multivariable fractional polynomials (MFP) model and Pearson correlation were used to study the dose-response relationship between maternal and neonatal plasma VitA levels, Logistic regression model to estimate the effect of maternal VitA nutritional status on neonatal VitA deficiency, and MFP model and Spearman correlation to describe the relationship between maternal VitA level and VitA placental transport ratio. RESULTS: The average retinol concentration of the pregnant women was (1.15±0.30) µmol/L, and the prevalence of VitA deficiency and marginal deficiency were 4.5% and 37.8%, respectively. Average retinol concentration of the neonates was (0.78±0.13) µmol/L, and no neonates were VitA deficiency, 28.2% of the neonates were marginal deficiency. After multivariable adjustment, the VitA level of the neonates was positively and linearly related to maternal VitA level (pm=1, P<0.05), with the corresponding Pearson correlation coefficient of 0.13 (P<0.01). As compared with the women with sufficient VitA, those with VitA deficiency (crude OR=2.20, 95%CI:1.04-4.66) and marginal deficiency (crude OR=1.43, 95%CI:1.01-2.02) had higher risks to deliver neonates with VitA marginal deficiency; while the risks turned to be non-significant after multivariable adjustment. The pregnant women with VitA deficiency had higher risk to deliver neonates with relative VitA deficiency before and after multivariable adjustment (crude OR=3.02, 95%CI:1.21-7.50; adjusted OR=2.76, 95%CI:1.05-7.22). The maternal VitA level was negatively and non-linearly correlated with placental transport ratio (pm= -0.5, P<0.05), with corresponding adjusted Spearman correlation coefficient of -0.82 (P<0.001). CONCLUSION: There was a positive linear dose-response relationship between VitA levels of newborns and pregnant women in third trimester, indicating that neonatal VitA storing levels at birth was affected by maternal VitA nutritional status.

[Epidemic characteristics of hand, foot and mouth disease (HFMD) and the lag effect of average daily temperature on the epidemic of HFMD in Beijing].

Objective: To analyze the epidemic characteristics of hand, foot and mouth disease (HFMD) in Beijing and explore the short-term lag effect of daily average temperature on HFMD. Methods: The incidence data and meteorological data of HFMD were collected from Xicheng District, Chaoyang District, and Changping District of Beijing between January 2009 and December 2018. The dose-response relationship and short-term lag effect of temperature and HFMD incidence were explored by the distributed lag non-linear model (DNLM). Results: From 2009 to 2018, a total of 97 210 cases of HFMD were confirmed in Xicheng District, Chaoyang District, and Changping District of Beijing. The incidence rate of HFMD in Xicheng district was 71.83/100 000, which was the lowest in three districts. The total annual average incidence was 146.89/100 000 in the three districts. The cases were concentrated from May to July, with a small peak in October to November. The ratio of male to female was 1.49∶1, and the median age of the patients was 3.08 (1.89, 4.39) years old, which showed a decreasing trend in children under 6 years old (Z=-30.11, P<0.01). The DNLM showed that the cumulative relative risk (RR) curve had a bimodal distribution, with RR of 1.36 (95%CI: 1.05-1.76) and 1.35 (95%CI: 1.10-1.66), and the peak values appeared at 4 ℃ and 26 ℃, respectively. Conclusions: The incidence rate of HFMD in Xicheng was the lowest in three districts of Beijing. In addition, the incidence of HFMD is seasonal, and the incidence is higher in spring and summer than that in autumn and winter. Daily average temperature had a lag effect on HFMD, which was different between high temperature and low temperature.

Association of elective cesarean delivery with metabolic measures in childhood: A prospective cohort study in China.

BACKGROUND AND AIMS: Cesarean delivery may increase the risk of childhood obesity, a precursor of metabolic syndrome (MetS). We aimed to investigate the association of elective cesarean delivery (ElCD) with MetS and its components in a Chinese birth cohort. METHODS AND RESULTS: This cohort included 1467 children (737 delivered by ElCD and 730 by spontaneous vaginal delivery [SVD]) who were followed up at the age of 4-7 years in 2013. MetS was defined as the presence of ≥3 components: central obesity, hypertriglyceridemia, low high-density lipoprotein (HDL), high fasting glucose, and hypertension. Of the 1467 children, 93 (6.3%) were categorized as having MetS: 50 (6.8%) delivered by ElCD and 43 (5.9%) by SVD. After multivariable adjustment, ElCD was not associated with MetS (adjusted odds ratio [AOR] 1.15, 95% confidence interval [CI] 0.74, 1.78) or certain components including hypertriglyceridemia, low HDL, and high fasting glucose but was associated with central obesity (AOR 1.33, 95% CI 1.02, 1.72) and hypertension (AOR 1.50, 95% CI 1.15, 1.96), as well as higher levels of total cholesterol (3.43 vs. 3.04 mmol/L; P < 0.001), low-density lipoprotein-cholesterol (1.77 vs. 1.67 mmol/L, P = 0.002), fasting glucose (5.08 vs. 5.02 mmol/L, P = 0.022), systolic (97.57 vs. 94.69 mmHg, P < 0.001)/diastolic blood pressure (63.72 vs. 62.24 mmHg, P < 0.001), and BMI (15.46 vs. 14.83 kg/m2, P < 0.001) than SVD. CONCLUSIONS: ElCD is not associated with MetS in early to middle childhood but is associated with its components including central obesity and hypertension, as well as various continuous indices.

[Mobile terminal-based survey on the birth characteristics for Chinese newborns].

OBJECTIVE: To describe the birth characteristics for Chinese newborns, to assess the feasibility of collecting basic data on maternal and child health, and to conduct relevant epidemiological studies by using mobile terminals. METHODS: From June 2016 to January 2017, pregnant women who delivered in hospitals were recruited in 166 hospitals scattered across 23 provinces of China. The data on their maternal and child health including delivery mode, gestational age and birth weight, were collected by self-administered questionnaires embedded in a mobile application. The incidences or means of cesarean section, preterm birth, birth weight, length and head circumference were calculated and compared with recognized national data, including 2005 Growth Standards for Chinese Children Under 7 Years of Age, 2006 World Health Organization Child Growth Standards and 2014 Chinese Neonatal Birth Weight Standards by Gestational Age. RESULTS: A total of 9 986 women were investigated, among whom those aged ≥35 years accounted for 11.7% and those received well education (college and above) accounted for 70.2%. The rate of cesarean section, preterm delivery, low birth weight and macrosomia were 38.1%, 4.5%, 2.2%, and 7.8%, respectively. The means were (3.33±0.44) kg [male (3.36±0.44) kg, female (3.29±0.43) kg] for birth weight, (50.97±2.32) cm [male (51.04±2.32) cm, female (50.89±2.32) cm] for birth length, and (33.99±1.56) cm [male (34.01±1.57) cm, female (33.97±1.55) cm] for head circumference, respectively. As compared with the national data, the cesarean section rate and birth weights by gestational age for term-born neonates were similar to the latest national data in 2014, while the means of birth weight and length were obviously higher than those of the 2005 Growth Standards for Chinese Children Under 7 Years of Age and 2006 World Health Organization Child Growth Standards. CONCLUSION: As compared with the national data 10 years ago, the mean birth weights for male and female newborns were increased by 40 g and 80 g respectively and mean lengths by 0.6 cm and 1.3 cm, but changes for mean head circumferences were negligible, indicating that the physical health condition for Chinese newborns improved significantly over past 10 years and emerging information technology likely provided a new approach for epidemiological research.

[Institutional delivery rate in minority inhabited areas of China from 1996 to 2017].

Objective: To describe the secular trends of institutional delivery (ID) rate in minority inhabited areas of China from 1996 to 2017 according to national health policies. Methods: The number of live births and IDs for each county/district in 31 provinces of China were derived from the datasets collected by the Office for National Maternal & Child Health Statistics of China. Information on health policies and ethnical areas was derived from official governmental websites. The calendar years were divided into three periods: pre-program period (1996 to 1999), program implementation period (2000 to 2008) and post-program period (2009 to 2017). Minority autonomous regions, autonomous prefectures, and autonomous counties were defined as minority inhabited areas. The ethnic that a county was classified into was determined by a principle of close proximity to the name of the county or its next higher level administrative division. A total of 700 counties in minority inhabited areas were included in the analysis. Results: A total of 45 684 265 live births including 35 098 855 delivered in institutions were analyzed. The ID rate in minority inhabited areas was 37.5% (696 221/1 856 164) in 1996 and 99.2% (2 371 209/2 390 131) in 2017, with an annual growth rate of 4.7%. During the 22-years period, the ID rates in the eastern, central and western regions increased simultaneously, with the annual growth rates of 3.1%, 4.2% and 4.9% respectively. The difference between the eastern and western regions decreased steadily from 16% in 1996 to <1% in 2017 and the difference between the urban and rural areas decreased from 32.1% in 1996 to <1% in 2017. Besides, the ID rates in Tibetan and Yi inhabited areas with lower baseline levels increased 73 and 63 percentage points respectively. The number of counties with the ID rate of <96% were substantially reduced from 589 in 1996 to 72 in 2017; the 71 counties were all located in national deep poverty-stricken areas named Three Districts and Three States, predominantly involving Tibetan (58), Yi (6), Uygur (2) and Lisu (2) ethnics. Conclusion: During the past 22 years, the ID rate in minority inhabited areas in China has dramatically increased, achieving the goal of 2 020 ahead of schedule, but there remains a few western counties where ID rates are still<96%, indicating that minority inhabited western areas should be focused in developing national policies concerning institutional delivery.

[HIV epidemic among pregnant women in China, 2016: trend and spatial analysis].

Objective: To describe the spatial distribution characteristics of the HIV prevalence among pregnant women in mainland China in 2016, providing scientific evidence for the prevention of mother-to-child transmission of HIV. Methods: Data on pregnant women and those living with HIV in 2016 for all counties in mainland China is from the National Maternal & Child Health Statistics dataset. To obtain robust estimates, 2 964 counties were merged into 344 cities. Spatial autocorrelation analysis and trend analysis were performed based on the city-level dataset to detailedly describe the characteristics of the spatial distribution. Results: A total of 14 879 082 pregnant women were included in the analysis, among whom 5 051 were diagnosed to be infected with HIV, giving an overall prevalence of 34.0 per 100 000 pregnant women. The prevalence was higher in the south than in the north, and decreased from the west (93.5/100 000) to the east(8.6/100 000 ), more specifically, the prevalence in the West region was 11 times as high as that in the East region(χ(trend)(2)=68.61, P<0.01). Stratified analysis by provinces showed that there were 6 provinces whose prevalence was >50.0 per 100 000, and they (Yunnan, Xinjiang, Sichuan, Guangxi, Guizhou and Chongqing) were all located in the West Region; pregnant women in these provinces accounted for 21% of all pregnant women, but the HIV cases accounted for 76% of all cases diagnosed in mainland China. Stratified analysis by cities showed that there were 30 cities whose prevalence was >100.0 per 100 000, and 28 of these cities were also located in the western provinces above. Furthermore, the global Moran's I (0.5, P<0.01) indeed indicated a strong clustered distribution across mainland China; 2 hot spots were observed in the Midwest of Xinjiang, and Yunnan and its bordering areas (Sichuan, Guizhou, Guangxi and Chongqing), while 1 cold spot in the central and east China. The HIV prevalence in the hot spots (183.6/100 000) was 23 times as much as that in the cold spot (8.1/100 000). Conclusion: The overall HIV prevalence for pregnant women who lived in mainland China in 2016 (34.0/100 000) ranked at low-level worldwide, but varied markedly across the whole country with 2 high-prevalence-clustered areas: the Midwest of Xinjiang Uygur Autonomous Region, and Yunnan province along with its bordering areas, indicating comprehensive intervention strategies especially targeted to the areas with high HIV prevalence should be developed.

[Screening different HPV genotypes infection and type-specific in cervical exfoliated cells of women in Yili area of Xinjiang Uygur Autonomous Region, China].

Objective: To investigate the infection status and genotype distribution of cervical human papillomavirus (HPV) in women of different ethnic groups and different ages in Yili, Xinjiang Uygur Autonomous Region (Xinjiang). Methods: By using the convenient sampling method, 54 760 women from November 2015 to May 2017 seeking for service in gynecological clinics in a general hospital in Yili, Xinjiang, were selected as the research subjects, and 3 445 samples of cervical mucous exfoliative cells were collected, and the social information of their ethnic and age was collected at the same time. The inclusion criteria were those with sexual life, cervical integrity, and ethnic groups for Han or Uygur or Kazak. PCR-reverse dot blot hybridization was used to detect HPV genotyping in exfoliated cells, and chi-square test was used to compare the difference of HPV positive rate among different ethnic groups. Then, according to ethnicity and age, the differences in positive rates of different ages and ethnic groups were compared in each layer. Results: The positive rate of HPV was 25.6% (882 cases), of which the Han, Uygur and Kazakh were 27.9% (564 cases), 22.9% (196 cases) and 21.6% (122 cases), and the difference was statistically significant (χ(2)=13.80, P=0.001). The most prevalent high-risk genotypes of Han women were HPV16/52/58, accounting for 24.8% (140 cases), 17.7% (100 cases) and 9.8% (55 cases), respectively. The most prevalent high-risk genotypes of Uygur women were HPV16/52/53, accounting for 34.2% (67 cases), 12.8% (25 cases), 9.2% (18 cases), respectively. The most prevalent high-risk genotypes of Kazak were HPV16/52/53, accounting for 37.7% (46 cases), 17.2% (21 cases), 12.3% (15 cases), respectively. The highest rate of HPV in Uygur patients aged ≥61 years was 41.5% (22 cases), and the lowest in group 36-40 years old, 15.9% (21 cases), the difference between different age groups was statistically significant (χ(2)=35.01, P<0.001). Conclusion: The positive rate of HPV infection among Han, Uygur and Kazak in Yili Prefecture of Xinjiang was different, and the HPV positive genotype differs among different ethnic groups.

[Secular trends of institutional delivery rate in China from 1996 to 2015].

Objective: To describe the secular trends of institutional delivery (ID) rate in China from 1996 to 2015, and to assess the impacts of national health policies on the ID rate. Methods: Data on the number of live births and IDs for districts/counties in 31 provinces of China was annually collected by the Office for National Maternal & Child Health Statistics of China. Information concerning the relevant policies was from official governmental websites, including the programme to reduce maternal mortality and eliminate neonatal tetanus (2000 to 2008), and ID subsidy programme in rural China (2009 to present). According to the programme to reduce maternal mortality and eliminate neonatal tetanus, the calendar years were categorized into three periods: pre-programme period (1996 to 1999), programme implementation period (2000 to 2008) and post-programme period (2009 to 2015). Results: A total of 244 398 010 live births were included in the analysis, in which 211 605 727 were delivered in institutions. During the 20 years, the ID rate steadily increased from 58.7% (6 309 255/10 739 816) in 1996 to 99.7% (13 583 658/13 626 948) in 2015, with a compound annual growth rate of 2.8%. Analyses stratified by economic regions or urban-rural areas showed notably consistent increases in ID rates, and the regional and urban-rural differences became nearly disappeared by 2015. The largest regional difference between East (71.6%, 2 540 896/3 547 423) and West (44.6%, 1 675 305/3 752 873) was 27% in 1996 and <1% in 2015 (East 99.9%[5 177 865/5 180 636]and West 99.0%[3 925 766/3 964 622]). The urban-rural difference was 22.7% in 1996 (urban 73.5%[2 756 531/3 748 703], rural 50.8%[3 552 724/6 991 113]) and 0.4% in 2015(urban 99.9%[6 257 853/6 262 763], rural 99.5%[7 325 805/7 364 185]). During the programme implementation period and the post-programme period, the ID rates in rural area increased faster than those in urban area, and the corresponding compound annual growth rates in rural area were 2.4 and 2.8 times of those in urban area; the ID rates in Middle and West regions increased faster than those in East region, and the corresponding compound annual growth rates in West region were 3.6 and 6.3 times of those in East region. By 2015, the ID rates in all provinces other than Tibet (90.5%[48 445/53 505]) and Qinghai (97.2%[60 836/62 600]) reached or were close to 100%. However, there were still 112 districts/counties with ID rates <96%, of which 39 with ID rates <80%; the 39 districts/counties were all located in four western provinces (Tibet 19, Sichuan 15, Qinghai 3, and Xinjiang 2). Conclusions: During the past 20 years, the ID rate in China has steadily increased and achieved the goal of the year 2020 ahead of schedule; the regional and urban-rural inequality in ID has nearly disappeared. Given universal two-child policy, it is of significance to strengthen existing achievements, focus on complicated pregnancies and comprehensively improve the capability and quality of ID services; meanwhile, it is also of significance to develop particular policies and explore the medical-aid model for the minority-inhabited western regions with lower ID rates.

Identification of driver pathways in cancer based on combinatorial patterns of somatic gene mutations.

With the availability of high-throughput technologies, a huge number of biological data (e.g., somatic mutation, DNA methylation and gene expression) in multiple cancers have been generated. A major challenge is to identify functional and vital driver mutation import for the initiation and progression of cancer. In this paper, we introduce a novel method, named Co-occurring mutated metagene Genetic Algorithm (CoGA), to solve the maximum weight submatrix problem, with the aim of distinguishing mutated driver pathways in cancer. The algorithm relies on the combinatorial properties of mutations in the same pathways: high coverage and mutual exclusivity, and the possible properties of mutations in different pathways: co-occurring pattern. We carried out the experiment with glioblastoma multiform (GBM) data. The experimental results show that compared with the original model, our algorithm has more potential to identify driver pathways in cancer with biological significance.

Isolation and characterization of atrazine-degrading strain Shewanella sp. YJY4 from cornfield soil.

UNLABELLED: Atrazine has been used worldwide for over 50 years as a chemical herbicide. A strain of bacteria, YJY4 which utilizes atrazine as its sole nitrogen source for growth was isolated from agricultural black soil in northeastern China. 16S rDNA sequencing identified YJY4 as a Shewanella sp. PCR analysis and sequencing confirmed that YJY4 contained atrazine-degrading atzA, atzB and atzC genes. These genes revealed high similarity with those in Pseudomonas sp. ADP and Arthrobacter sp. TC1. The strain YJY4 was observed to degrade atrazine (100 mg l(-1) ) to cyanuric acid completely after 36 h. To the best of our knowledge, YJY4 was the first reported Shewanella sp. to grow in pure culture with atrazine serving as a sole source of nitrogen. Therefore, YJY4 may help with atrazine biodegradation and may become an abundant resource of atrazine degradation strains. SIGNIFICANCE AND IMPACT OF STUDY: A new isolated strain, YJY4 showed high atrazine-degrading ability, being able to degrade 100 mg l(-1) atrazine completely in 36 h. Strain YJY4 was identified as Shewanella sp. and contained atrazine-degrading atzA, atzB and atzC genes. This study examined the degradation mechanism and metabolic ability of this strain and for the bioremediation of contaminated environments, provides more strain selection and determines the strain of atrazine bioremediation potential.

Investigation of snap-through and homoclinic bifurcation of a magnet-induced buckled energy harvester by the Melnikov method.

Snap-through is used to improve the efficiencies of energy harvesters and extend their effective frequency bandwidths. This work uses the Melnikov method to explore the underlying snap-through mechanism and the conditions necessary for homoclinic bifurcations in a magnet-induced buckled energy harvester. First, an electromechanical model of the energy harvester is established analytically using the Euler-Bernoulli beam theory and the extended Hamilton's principle. Second, the Melnikov function of the model is derived, and the necessary conditions for homoclinic bifurcations and chaos are presented on the basis of this model. The analysis reveals that the distance between the magnets and the end-block mass significantly affect the thresholds for chaotic motions and the high-energy solutions. Numerical and experimental studies confirm these analytical predictions and provide guidelines for optimum design of the magnet-induced buckled energy harvester.

Analysis of genetic diversity and population structure in a tomato (Solanum lycopersicum L.) germplasm collection based on single nucleotide polymorphism markers.

Knowledge of genetic diversity is important to assist breeders in the selection of parental materials and in the design of breeding programs. In this study, we genotyped 348 inbred tomato lines, representing vintage and contemporary fresh-market varieties, by using 52 single nucleotide polymorphisms (SNPs); 45 of these were found to be polymorphic. The average minor allele frequency and unbiased expected heterozygosity were 0.315 and 0.356, respectively. Population structure analysis revealed that contemporary germplasm could be distinctly divided into six subpopulations representing three market classes and breeding programs (pink, green, and red). Vintage germplasm could be separated into at least two subpopulations, and more admixtures were found in vintage lines than in contemporary lines. These findings indicate that contemporary inbred lines are more diversified than vintage inbred lines. AMOVA of vintage and contemporary lines was performed. A significant difference was found (P < 0.01), which explained 17.4% of the total genetic variance. Subsequently, we constructed a core collection using 45 polymorphic SNP markers. The data showed that all alleles were captured by only 2% of lines, indicating that more alleles, as well as rare alleles, could enable more variation to be captured in the core collection. These data allow us to discard redundant inbred tomato lines and to select elite inbred lines, which will accelerate the breeding process.

Inhibitory effects of spironolactone on myocardial fibrosis in spontaneously hypertensive rats.

This study evaluated the inhibitory effects of spironolac-tone, a non-selective aldosterone receptor antagonist, on hypertension-induced myocardial fibrosis. Collagen I and III contents was detected in the myocardial tissue of spontaneously hypertensive rats (SHRs) after spironolactone administration. Twenty male SHRs were assigned to the spironolactone group or control group (N = 10 each); 7 Wistar-Kyoto rats (WKY) were also used. Spironolactone dissolved in ddH2O was administered via gavage at a dosage of 20 mg·kg(-1)·day(-1). Meanwhile, the control and WKY groups were administered equivalent volumes of ddH2O for 16 weeks. Western blotting was used to detect the contents of collagen I in myocardial tissue; observations were performed using polarizing microscopy, and the area integration and ratio of collagen I/III were subsequently calculated. Compared to the WKY group, col-lagen I synthesis was significantly higher in the control group (1.87 ± 0.2 vs 1.21 ± 0.7, P < 0.05). After 16 weeks of treatment, collagen I contents were significantly lower in the spironolactone group than in the control group (1.42 ± 0.05 vs 1.87 ± 0.2, P < 0.05). The ar-eas of collagen I and collagen I/III ratio were significantly smaller in the spironolactone group than in the control group (6400 ± 259 vs 12,019 ± 734 pixels, 15.64 ± 1.34 vs 20.8 ± 3.04 pixels, respec-tively; P < 0.05). However, there were no significant differences in the area of collagen III among the three groups. In conclusion, spi-ronolactone improves myocardial collagen deposition, preventing myocardial fibrosis in SHRs.

Functional characterization of genetic variants in the porcine TLR3 gene.

Toll-like receptor 3 (TLR3) recognizes double-stranded RNA, which is a molecular signature of viruses, and plays a pivotal role in host defense against viral invasion. Polymorphisms in the human TLR3 gene have been shown to affect the receptor function and to be associated with a variety of diseases, suggesting correlations between TLR3 polymorphisms and the disease resistance/susceptibility in pigs. In this study, 5 known non-synonymous single nucleotide polymorphisms (SNPs) in the coding sequences of the porcine TLR3 gene - c.800C>T (p.T267M), c.933A>G (p.I311M), c.1116A>T (p.K372N), c.2129C>G (p.T710S), and c.2160T>G (p.I720M) - were analyzed for their effect on receptor function in transiently transfected PK-15 cells by using a luciferase reporter assay. In addition, the distribution of SNP c.933A>G was analyzed among pig populations. SNP c.933A>G significantly decreased the response to poly(I:C) (P < 0.05), as represented by the weaker induction of firefly luciferase relative to that achieved by wild-type TLR3. SNP c.933A>G results in the alteration of conserved amino acids in the highly conserved segment of the 12th leucine repeat region and is conserved among TLR3 orthologs from fishes to primates. Moreover, together with the results of previous studies, the results of the present study revealed that SNP c.933A>G is found solely in local Chinese pig breeds. These results suggested that SNP c.933A>G plays a role in porcine disease resistance/susceptibility.

The impact of cesarean section on offspring overweight and obesity: a systematic review and meta-analysis.

Studies have reported inconsistent results concerning the association of cesarean section with offspring obesity. We performed a systematic review and meta-analysis to examine whether cesarean section increases the risk of later overweight and obesity. Pubmed, Embase and Web of Science were searched using different combinations of two groups of keywords: 'cesarean' and 'overweight/obesity'. Cohort or case-control studies that reported the association of cesarean section with childhood (3-8 years), adolescence (9-18 years) and/or adult (>19 years) overweight/obesity were eligible. Where possible, adjusted risk estimates were pooled using a random effects model; otherwise unadjusted estimates were pooled. Statistical heterogeneity was assessed with I(2) statistics; the values of 25%, 50% and 75% were considered to indicate low, medium and high heterogeneity, respectively. We conducted a subgroup analysis to identify the sources of heterogeneity according to study quality defined on the basis of the Newcastle-Ottawa Scale. In total, two case-control and seven cohort studies were identified for the literature review and 15 separate risk estimates were included in the meta-analysis. The overall pooled odds ratio (OR) of overweight/obesity for offspring delivered by cesarean section compared with those born vaginally was 1.33 (95% confidence interval (CI) 1.19, 1.48; I(2)=63%); the OR was 1.32 (1.15, 1.51) for children, 1.24 (1.00, 1.54) for adolescents and 1.50 (1.02, 2.20) for adults. In subgroup analysis, the overall pooled OR was 1.18 (1.09, 1.27; I(2)=29%) for high-quality studies and 1.78 (1.43, 2.22; I(2)=24%) for medium-quality (P for interaction=0.0005); no low-quality studies were identified. The ORs for children, adolescents and adults all tended to be lower for high-quality studies compared with medium-quality studies. Our results indicated that cesarean section was moderately associated with offspring overweight and obesity. This finding has public health implications, given the increase in cesarean births in many countries.