Guodong Ding

Prenatal low-level mercury exposure and neonatal anthropometry in rural northern China.

Mercury (Hg) is a ubiquitous heavy metal that can negatively affect human health; however, few studies have examined the impact of prenatal low-level Hg exposure on fetal growth. We investigated prenatal exposure levels of Hg and the relationship between Hg levels and neonatal anthropometrics, including birth weight, length, and head circumference. A total of 258 mother-infant pairs were recruited from a rural community located on the southern coastal area of Laizhou Bay of the Bohai Sea in northern China between September 2010 and December 2011. We measured maternal and cord whole blood Hg levels and examined their association with neonatal anthropometrics. The geometric means (GMs) of Hg in maternal and cord whole blood were 0.84μgL(-1) and 1.46μgL(-1), respectively. The Hg exposure levels in our study population were much lower than those reported in previous domestic studies. No significant associations were found between maternal or cord blood Hg levels and birth weight, length, and head circumference. However, our results should be interpreted with caution given the high toxicity of Hg and its persistence in the body. Studies focusing on long-term adverse outcomes are needed to further examine the cumulative effects of low-level Hg exposure.

Association between prenatal exposure to polybrominated diphenyl ethers and young children's neurodevelopment in China.

The use of polybrominated diphenyl ethers (PBDEs) has been dramatically increasing over the last two decades in China. Animal studies suggest that prenatal exposure to PBDEs may result in neurodevelopmental deficits. Two hundred thirty-two participating mothers were recruited from a prospective birth cohort in rural northern China between September 2010 and February 2012. We analyzed 232 cord blood specimens for selected PBDE congeners and examined their association with childrens developmental quotients (DQs) at 12 (n=192) and 24 (n=149) months of age based on the Gesell Developmental Schedules (motor, adaptive, language, and social domains). There were no substantial differences by demographic characteristics among the three time points: baseline, 12 and 24 months of age. Median cord blood levels of PBDE congeners 47, 99, 100, and 153 were 3.71, 6.70, 2.63, and 2.19 ng/g lipid, respectively. At 12 months of age, neither the individual nor total (the sum of BDEs 47, 99, 100, and 153) congener levels were associated with any of the four domain DQs. However, at 24 months of age, a 10-fold increase in BDE-99 levels was associated with a 2.16-point decrease [95% confidence interval (CI): -4.52, -0.20] in language domain DQs and a 10-fold increase in BDE-47 levels was associated with a 1.89-point decrease (95% CI: -3.75, -0.03) in social domain DQs. Prenatal exposure to PBDEs was associated with lower DQs in young children. The results contribute to the growing evidence that PBDEs could act as developmental neurotoxicants,and the findings have implications for childrens environmental health in China.

Fully integrated micro electromagnetic vibration energy harvesters with micro-patterning of bonded magnets

This paper presents the fabrication and characterization of a novel fully integrated micro electromagnetic vibration energy harvester using micro-patterning of bonded magnets. The magnetic material utilized is a polymer composite, consisting of a commercially available NdFeB powder dispersed in epoxy resin to a weight loading percentage of 90%. The prototype is fabricated using UV-LIGA technology and microelectroplating technology. The whole volume of the structure is about 20 mm3. Testing results show that the fabricated vibration energy harvesters can generate a maximum peak-peak voltage of 20.9 μV at the devices resonance frequency of 365 Hz and input acceleration of 1 g (9.8 m/s2).

Application of A global reference for fetal‐weight and birthweight percentiles in predicting infant mortality

To determine whether the recently published A global reference for fetal‐weight and birthweight percentiles (Global Reference) improves small‐ (SGA), appropriate‐ (AGA), and large‐for‐gestational‐age (LGA) definitions in predicting infant mortality.

Associations of maternal pre-pregnancy body mass index and gestational weight gain with birth outcomes in Shanghai, China.

Recent data suggests that abnormal maternal pre-pregnancy body mass index (BMI) or gestational weight gain (GWG) is associated with unfavorable delivery outcomes. However, limited clinical evidence is available to support this correlation in China. Participating 510 mother-infant pairs were recruited from the Shanghai First Maternity and Infant Hospital, China, between January 1st and 30th 2016. Maternal pre-pregnancy BMI was categorized according to the China’s classification and GWG according to the 2009 Institute of Medicine recommendations (IOM). Linear regression tested the associations between pre-pregnancy BMI or GWG and length of gestation, birthweight, length, and head circumference. Logistic regression assessed the associations between pre-pregnancy BMI or GWG and macrosomic, small- (SGA) and large- (LGA) for-gestational-age infants. Overweight/obese women showed increased length of gestation and birthweight, but did not have a higher risk of macrosomic and LGA infants compared with normal weight women. Women with excessive GWG showed increased length of gestation, birthweight, length, and head circumference, and were more likely to deliver macrosomic and LGA infants compared with women with adequate GWG. Although a relatively low proportion of women from Shanghai area are overweight/obese or exhibit excessive GWG, both high pre-pregnancy BMI and excessive GWG influence perinatal outcomes.

Prenatal low-level phenol exposures and birth outcomes in China

Phenolic compounds are among the endocrine disruptors which are widely used in daily life products. Studies in laboratory animals showed reproductive and developmental effects. In spite of widespread exposure to phenols, only few studies examined their effects on human development. This study was designed to investigate the relationship between antenatal phenol exposure and birth outcomes in a Chinese obstetric population. Four hundred ninety-six mother-infant pairs recruited from the Laizhou Wan prospective birth cohort in northern China between 2010 and 2013 were included in the study. We measured two phenol metabolites in maternal urine at delivery and examined their associations with birth outcomes including birth weight, crown-heel length, head circumference, gestational age, and ponderal index. Median levels of bisphenol A (BPA) and triclosan (TCS) in urine were 1.07 and 0.50μg/g creatinine, respectively. After adjusting for confounders, a 10-fold increase in BPA levels was associated with a 0.63cm [95% confidence interval (CI): 0.25 to 1.01] increase in birth length among boys, but not among girls. No associations were found between TCS levels and any birth outcomes. The positive association of prenatal low-level BPA exposures with anthropometric measures observed among boys, suggests gender differences in the response to antenatal phenol exposure. Given the variability in urinary phenol levels reported during pregnancy, our findings based on levels of the target biomarkers in a single urine sample need to be confirmed in additional studies.

A multidirectional-sensitive inertial microswitch with electrophoretic polymer-metal composite fixed electrode for flexible contact

A multidirectional-sensitive inertial microswitch with polymer-metal composite fixed electrode has been designed and fabricated based on non-silicon surface micromachining in the present work. The microswitch can sense the applied accelerations from any directions in xoy plane and positive z-axis. Its vertical composite fixed electrode is completed by electroplating and electrophoretic deposition, which can realize a flexible contact between the electrodes and eliminate the bouncing phenomenon and prolong the contact time. As a result, the stability and reliability of the inertial switch could be greatly improved. The test results show that the threshold acceleration of the fabricated prototype is generally uniform (~70g) in different sensitive directions in xoy plane and z-axis. The contact time of the microswitch with composite fixed electrode is ~110μs in vertical direction, which is longer than that (~65μs) of one without polymer.

Cultural postpartum practices of ‘doing the month’ in China

For over 2000 years, Chinese women have practiced the traditional postpartum ritual called ‘doing the month’, during which new mothers follow specific regulations for one month following delivery. In this article, Guodong Ding and Ying Tian of Shanghai Jiao Tong University School of Medicine, Jing Yu of Shanghai Jiao Tong University Affiliated Sixth People’s Hospital, and Angela Vinturache of the Department of Obstetrics & Gynaecology, John Radcliffe Hospital, Oxford, discuss the need for greater understanding of this traditional practice in order to provide appropriate medical treatment and unite traditional and modern postpartum health.

Association between bisphenol a exposure and idiopathic central precocious puberty (ICPP) among school-aged girls in Shanghai, China

BACKGROUND Bisphenol A (BPA) is a well-known and widely used endocrine disrupter, but data on its association with childhood reproductive development are limited. OBJECTIVES We investigated the possible relationship between exposure to BPA and idiopathic central precocious puberty (ICPP) in school-aged girls. METHODS We conducted a 1:1 matched case-control study in Shanghai, China, between July 2011 and September 2012. This study included 136 school-aged (6 to 9 years old) girls diagnosed with ICPP and 136 controls matched for age and body mass index (BMI). We measured the urinary BPA concentrations of all the girls and examined the association with odds of having ICPP. Laboratory examinations including serum estradiol (E2) levels, basal and gonadotropin-releasing hormone (GnRH)-stimulated luteinizing hormone (LH), and follicle-stimulating hormone (FSH) levels, bone ages (BA), and uterine and ovarian sizes were conducted in the ICPP girls. RESULTS Median concentrations of urinary BPA in the ICPP and control groups were 6.35 and 1.17 μg/g creatinine (Cr), respectively (p < 0.001). After adjustment for confounders, compared to those with the lowest concentrations of BPA, the highest concentrations were associated with a 9.08-fold increased odds of having ICPP [odds ratio (OR) = 9.08, (95% confidence interval (CI): 2.83-29.15)]. In the ICPP group, modest negative correlation was present between urinary BPA concentrations (μg/g Cr) and peak FSH levels [β = -0.090 (95% CI: -0.178, -0.003), p = 0.044]. CONCLUSIONS Our findings suggest that BPA exposure is associated with increased odds of having ICPP in school-aged girls, and the potential mechanism may be attributable to the relatively low FSH levels.

A novel inertial microswitch with synchronous follow-up compliant electrodes for extending output switch-on pulse width

This paper reports a novel inertial microswitch with synchronous follow-up compliant electrodes for extending output switch-on pulse width. The flexible movable electrode and stationary electrode are proposed to keep a continuous duration contact by double-stair and spring-shape structures, which can not only extend the output switch-on pulse width but also reduce the impact bounces. Then the inertial microswitch has been fabricated using surface micromachining and multilayer electroplating technology. The comparison testing results show that there is no contact bouncing behavior can be observed under ∼466g half sine-wave shock acceleration and the test output switch-on pulse width can reach 390μs, which is longer than that in the traditional design.