Di(2-ethylhexyl) phthalate (DEHP), as a widespread environmental pollutant and an endocrine disruptor, can disturb the homeostasis of thyroid hormones (THs). In order to elucidate roles of the MAPK ...and PI3K/Akt pathways and hepatic enzymes in thyroid-disrupting effects of DEHP, Sprague-Dawley rats were dosed with DEHP by gavage for 30 consecutive days; Nthy-ori 3-1 cells were treated with DEHP with NAC, k-Ras siRNA or inhibitors (U0126 and wortmannin). Results showed that DEHP led to histopathologic changes in rat thyroid and liver, such as the decrease in thyroid follicular cavity diameter, hepatocyte edema. Triiodothyronine (T3), thyroxine (T4) and thyrotropin releasing hormone (TRH) were reduced. DEHP caused ROS production, oxidative stress and k-Ras upregulation, thereby activating the ERK and Akt pathways in vivo and in vitro. Moreover, TRH receptor (TRHr) level was elevated after the activation of the Akt pathway and was downregulated after the inhibition of the Akt pathway. However, TRHr was not modulated by the ERK pathway. Additionally, hepatic enzymes, including Ugt1a1, CYP2b1, Sult1e1, and Sult2b1, were significantly induced after DEHP exposure. Taken together, DEHP can perturb TH homeostasis and reduce TH levels. The activated Ras/Akt/TRHr pathway and induced hepatic enzymes play vital roles in thyroid-disrupting effects of DEHP.
In this work, the acoustic performance of an anechoic layer, which contains horizontally-distributed cylindrical holes, has been studied using identified viscoelastic dynamic parameters. First, the ...reflection coefficients of two different viscoelastic anechoic layers (one solid and the other perforated), tested in a water-filled pipe, have been used to develop the identification method for viscoelastic dynamic parameters. In the proposed method, the complex longitudinal wavenumber and the complex transverse wavenumber can be obtained by solving the characteristic equation of viscoelastic cylindrical tube. Then, simulations have been performed using COMSOL software to predict the acoustic performance of the anechoic layer. Based on the model and the identified viscoelastic parameters, the effects of different structural properties, including the radius of hole, the hole horizontal spacing, and the arrangements of holes, on the sound absorption of anechoic layer have been analyzed and discussed. Particularly, the acoustic performance of an anechoic layer under oblique incidence has also been considered.
Purpose
The aim of this study was to examine the association between periconceptional folic acid (FA) supplementation and risk of preterm birth.
Methods
We conducted a retrospective cohort study in ...women aged 18–49 who participated in the NFPHEP from 2010 to 2018, and had a singleton livebirth in 129 counties in southwest China. Participants were divided into four groups according to the time period starting FA use: no use, after the last menstrual period, at least 1–2 months before the last menstrual period, at least 3 months before the last menstrual period. The outcomes were preterm birth (gestation < 37 weeks) and early preterm birth (gestation < 34 weeks).
Results
201,477 women were included and 191,809 (95.2%) had taken FA during periconception. Compared with women who did not take FA, women who started taking FA 1–2 months before their last menstrual period had a 15% lower risk of preterm birth (aOR = 0.85, 95% CI 0.79–0.92), and women who started taking FA at least 3 months before their last menstrual period had a 20% lower risk of preterm birth (aOR = 0.80, 95% CI 0.75–0.87), but women who started taking FA after their last menstrual period did not appear to reduce the risk of preterm birth.
Conclusions
In this study of 200,000 Chinese women, periconceptional supplementation with FA was associated with a lower risk of preterm birth. Women who started taking FA at least 3 months before their last menstrual period were more likely to reduce the risk of preterm birth.
Abstract
Background
Globally, the prevalence of anemia among women of reproductive age is about 29.4%, and anemia impacts about 40% of pregnant women and more than 20% of non-pregnant women. We ...conducted a longitudinal observational study of anemia in pregnant and non-pregnant women, and analyzed the association between the prevalence of anemia and sociodemographic characteristics of women in southwest China.
Methods
This study was a longitudinal observational study which involved 640,672 women aged 18–49 years from 129 counties in southwest China. Data were from databases of National Free Preconception Health Examination Project (NFPHEP) and electronic medical records of local hospitals. We adjusted the diagnostic thresholds of anemia for altitude. The prevalence of anemia was expressed in percentages and 95% confidence intervals (95% CI). The association between the prevalence of anemia and sociodemographic characteristics of pregnant and non-pregnant women were analyzed using univariate and multivariate logistic regression method, expressed in crude odds ratio (cOR), adjusted odds ratio (aOR) and 95%CI.
Results
Of the 640,672 participants, 121,254 women suffered from anemia, with the prevalence of 18.9% (95%CI: 18.8–19.0%). From 2014 to 2018, the prevalence of anemia declines from 23.0–16.4%.The prevalence was 21.6% in the first trimester, higher than women in non-pregnancy (17.4%) and women in the third trimester (10.5%). Results from the multivariable logistic regression showed that women aged 18–20 (aOR = 1.28) or over 35 years old (aOR = 1.07), being farmers (aOR = 1.42), being ethnic minorities (aOR: 1.19 ~ 1.73), during the first trimester (aOR = 1.32) were more likely to be anemic.
Conclusions
Although the anemia prevalence of women of reproductive age has been decreasing in recent years, the prevalence of anemia is still high in pregnant and non-pregnant women in southwest China, especially during the first trimester. Women who were older or younger, being farmers, being ethnic minorities were at high risk of anemia. Anemia in women of reproductive age cannot be neglected.
Seasonal patterns of preterm birth were identified in previous studies, but the effect of conception season on preterm birth has not been extensively studied. Based on the notion that the etiological ...roots of preterm birth lie in the beginning of pregnancy, we did a population-based retrospective cohort study in Southwest China to examine the effects of season of conception and month of conception on preterm birth.
We did a population-based retrospective cohort study in women (aged 18-49) who participated in the NFPHEP from 2010 to 2018, and had a singleton livebirth in southwest China. According to the time of the last menstruation reported by the participants, month of conception and season of conception were then ascertained. We used multivariate log-binomial model to adjust the potential risk factors for preterm birth and obtained adjusted risk ratio (aRR) and 95% confidence intervals (95%CI) for conception season, conception month and preterm birth.
Among 194 028 participants, 15 034 women had preterm birth. Compared with pregnancies that were conceived in the summer, pregnancies that were conceived in the spring, autumn and winter had the higher risk of preterm birth (Spring: aRR = 1.10, 95% CI: 1.04-1.15; Autumn: aRR = 1.14, 95% CI: 1.09-1.20; Winter: aRR = 1.28, 95% CI: 1.22-1.34) and also had a higher risk of early preterm birth (Spring: aRR = 1.09, 95% CI: 1.01-1.18; Autumn: aRR = 1.09, 95% CI: 1.01-1.19; Winter: aRR = 1.16, 95% CI: 1.08-1.25). Pregnancies in December, and January had a higher risk of preterm birth and early preterm birth than pregnancies that were conceived in July.
Our study found that preterm birth was significantly related to season of conception. Preterm and early preterm birth rates were the highest among pregnancies that were conceived in winter, and the lowest among pregnancies in summer.
The progression of global warming and increase in instances of extreme weather have received considerable attention. We conducted a cohort study on women of childbearing age in Yunnan Province, ...examined the association between ambient temperature and humidity on preterm birth and evaluated the effects of extreme weather during early pregnancy and before parturition on preterm birth.
We conducted a population-based cohort study on women of childbearing age 18-49 years who participated in National Free Preconception Health Examination Project (NFPHEP) in Yunnan Province from January 1, 2010, to December 31, 2018. Meteorological data, namely daily average temperature (°C) and daily average relative humidity (%), were obtained from China National Meteorological Information Center. Four exposure windows were explored: 1 week of pregnancy, 4 weeks of pregnancy, 4 weeks before delivery, and 1 week before delivery. We used a Cox proportional hazards model and adjusted the potential risk factors for preterm birth to obtain the effects of exposure to temperature and humidity on preterm birth among the stages of pregnancy.
At 1 week of pregnancy and at 4 weeks of pregnancy, the association between temperature and preterm birth was U-shaped. The correlation between relative humidity and the risk of preterm birth was n-type at 1 week of pregnancy. The correlation between preterm birth and temperature and relative humidity at 4 weeks before delivery and at 1 week before delivery is J-shaped. Low temperature and low humidity were protective factors against preterm birth, whereas high temperature and high humidity were risk factors for preterm birth.The effects of high temperature and extremely high temperature were the strongest at 4 weeks before delivery, with HRs of 1.417 (95% CI: 1.362-1.474) and 1.627 (95% CI: 1.537-1.722), respectively. The effects of extremely low humidity and low humidity were strongest at 1 week before delivery, with HRs of 0.681 (95% CI: 0.609-0.761) and 0.696 (95% CI: 0.627-0.771), respectively.
Temperature and relative humidity affect preterm birth differently for each pregnancy stage. The effects of meteorological factors on pregnancy outcomes such as premature birth should not be ignored.
Objective
Preterm birth is a major healthcare problem and has been rising gradually in the past three decades in China. Yet the ethnic differences in the rates and distributions of preterm birth ...remain largely unknown in China. This study used data from Yunnan, a multiethnic province, to explore the differences in preterm birth across ethnicities.
Methods
A population-based observational study was conducted based on data from the National Free Preconception Health Examination Project in rural Yunnan from Jan 1, 2014 to Dec 31, 2018. Pregnancies with at least one livebirth were included in this study. We estimated the rates and 95% confidence intervals (CIs) of overall preterm birth (born < 37 weeks’ gestation), moderate to late preterm birth (born between 32 and <37 weeks’ gestation), very preterm birth (born between 28 and 31 weeks’ gestation), and extremely preterm birth (born < 28 weeks’ gestation) across maternal ethnicity and compared them using log-binomial regressions. Multivariable log-binomial regressions were used to assess the association between maternal ethnicity and preterm birth with adjustment for potential confounders, including year of delivery, maternal age at delivery, education, occupation, pre-pregnancy body mass index, history of chronic disease, history of preterm birth, smoking and drinking alcohol during early pregnancy, and parity and multiple pregnancy of current pregnancy.
Results
Among 195,325 women who delivered at least one live baby, 7.90% (95% CI, 7.78–8.02%) were born preterm. The rates of moderate to late preterm birth, very preterm birth, and extremely preterm birth were 6.20% (95% CI, 6.09–6.30%), 1.18% (95% CI, 1.13–1.23%), and 0.52% (95% CI, 0.49–0.56%), respectively. The rates of overall preterm birth, moderate to late preterm birth, very preterm birth, and extremely preterm birth differed across maternal ethnicity. The preterm birth rates in Dai (10.73%), Miao (13.23%), Lisu (12.64%), Zhuang (11.77%), Wa (10.52%), and Lagu (12.34%) women were significantly higher than that in Han women, and the adjusted relative risks were 1.45 95% CI, 1.36, 1.54, 1.74 (95% CI, 1.62, 1.86), 1.60 (95% CI, 1.47, 1.75), 1.60 (95% CI, 1.46, 1.75), 1.40 (95% CI, 1.22, 1.60), and 1.67 (95% CI, 1.50, 1.87) respectively. There was no difference in preterm birth rate between Han women and Hani, Bai, or Hui women.
Conclusion
This study found notable differences in the rates of preterm birth and its sub-categories across maternal ethnicities, which were especially higher in ethnic minority women. The findings suggest that greater efforts to reduce ethnic inequalities in preterm birth. Future studies are warranted to understand the drivers of ethnic inequalities in preterm birth in China.
Hepatitis B is a potentially life-threatening liver infection caused by hepatitis B virus (HBV) and China has the largest disease burden. We aim to understand the ethnic disparities in HBV infection ...among the married reproductive-age couples planning for pregnancy in Yunnan, a multiethnic province in Southwest China, to increase the health equities within the hepatitis response in China.
A population-based cross-sectional study was performed. Couples aged 20-49 years in rural Yunnan were enrolled through the National Free Preconception Health Examination Project from Jan 2014 to Dec 2019. HBsAg-positive couples were defined as couples in which one or both were HBsAg-positive, and HBsAg- and HBeAg-positive couples were defined as couples in which one or both were HBsAg- and HBeAg-positive. The HBV prevalence of positive couples was estimated by ethnicity. Multivariate logistic regression analyses were used to assess the association between ethnicity and HBsAg status.
Overall, 63,513 of 1,060,643 couples (5.99%, 95% CI, 5.94%-6.03%) were HBsAg-positive, and 15,898 of 63,513 HBsAg-positive couples (25.03%, 95% CI 24.69%-25.37%) were HBsAg- and HBeAg-positive couples in rural Yunnan. The highest prevalence of HBsAg-positive couples was in the Miao and Miao ethnicity (12.04%) and Zhuang and Zhuang ethnicity (9.76%), and the risk of HBV infection of wives/husbands in these ethnic groups was significantly higher than that in the Han and Han ethnicity. Additionally, the HBsAg prevalence in wives/husbands has increased with the positive status of HBsAg and HBeAg of their spouses.
The HBV prevalence in reproductive-age couples was intermediate (6% of 1 million couples) in rural Yunnan, China, with the highest in the Miao and Zhuang ethnicities. There are still large ethnic disparities in HBV infection in China. Therefore, China should make great efforts, especially giving priority to ethnic minorities and taking positive couples as an important unit of care, to equitably eliminate the HBV intrafamilial transmission.
Rivers in the Liaohe River Estuary area have been seriously polluted by discharges of wastewater containing petroleum pollutants and nutrients. In this paper, The Enhanced Stream Water Quality Model ...(QUAL2K) and its revised model as well as One-dimensional Tide Mean Model (1D model) were applied to predict and assess the water quality of the tidal river reach of the Liaohe River Estuary. Dissolved oxygen (DO), biochemical oxygen demand (BOD₅), ammonia nitrogen (NH₃-N) and total phosphorus (TP) were chosen as water quality indices in the two model simulations. The modelled results show that the major reasons for degraded rivers remain petroleum and non-point source pollution. Tidal water also has a critical effect on the variation of water quality. The sensitivity analysis identifies that flow rate, point load and diffuse load are the most sensitive parameters for the four water quality indices in the revised QUAL2K simulation. Uncertainty analysis based on a Monte Carlo simulation gives the probability distribution of the four water quality indices at two locations (6.50 km and 44.84 km from the river mouth). The statistical outcomes indicate that the observed data fall within the 90% confidence intervals at all sites measured, and show that the revised QUAL2K gives better results in simulating the water quality of a tidal river.
The efficient removal of hydrogen sulfide (H2S) from exhaust emissions is a great challenge to chemical industries. Selective catalytic oxidation of H2S into elemental sulfur is regarded as one of ...the most promising approaches to alleviate environmental pollution, while recycling sulfur resources. It is therefore highly desirable to develop efficient catalysts for the conversion of H2S to sulfur under mild reaction conditions. Here we present a nitrogen-rich carbon obtained by the direct thermal treatment of commercial polyaniline (PANI) for the selective oxidation of H2S in a continuous way at relatively low temperature (180 °C). The efficient conversion of H2S over the N-rich carbon catalysts was attributed to the in situ generation of pyridine-N on the carbon matrix, which served as the active sites to promote the absorption and dissociation of H2S molecules, achieving a superior catalytic conversion rate of 99% and selectivity up to 95% at 180 °C.
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