Publications by authors named "Mengyuan Ren"

16 Publications

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Early pregnancy loss: Do Per- and polyfluoroalkyl substances matter?

Environ Int 2021 Aug 26;157:106837. Epub 2021 Aug 26.

Reproductive Medical Center, Peking University People's Hospital, Beijing 100044, China.

Per- and poly-fluorinated substances (PFASs) with endocrine disrupting effect can efficiently transfer across the blood-follicle barrier. However, it is still controversial and attracting extensive public concern that whether PFASs can affect the human fertility potential. Therefore, we aimed to analyze the associations of women's exposure to PFASs with pregnancy loss, the relevant processes of fertilization, zygote implantation, and embryo development by using a prospective cohort study. The women undergoing in vitro fertilization-embryo transfer (IVF-ET) treatment were recruited in Beijing City (Beijing Center) and Yantai City (Yantai Center) in China during 2015-2017. A total of 305 women were recruited before the IVF-ET treatment. Twelve PFASs were measured in their serum samples collected in the day before the IVF-ET treatment, as well as in the human chorionic gonadotropin (hCG) day. The three IVF-ET outcomes were included, i.e. hCG test negative, clinical pregnancy failure (CPF), and preclinical spontaneous abortion. Nine serum PFASs had detection rate of >70% in Beijing and Yantai centers. The exposure patterns to PFASs between these two centers were overall different. For Beijing Center, we only found a positive association of perflurodecanoic acid (PFDA) with the risk of CPF [RR = 2.28 (95 %CI: 1.02-5.11)], but there is a reverse trend in Yantai Center with [RR = 0.45 (95 %CI: 0.23-0.85)]. However, the serum concentration of PFDA in Beijing Center was relatively lower than that of Yantai Center. Other significant associations of the detected PFASs with the IVF-ET outcomes, or with the relevant clinical processes, were not found. The multi-pollutant regression model of the Bayesian kernel machine regression suggested that there were no joint effects between various PFASs on the concerned outcomes. Overall, we suggest that most PFAS were not associated with early pregnancy loss at the current exposure levels. As for the PFDA, there may exist susceptibility of different populations.
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http://dx.doi.org/10.1016/j.envint.2021.106837DOI Listing
August 2021

Associations between endocrine-disrupting heavy metals in maternal hair and gestational diabetes mellitus: A nested case-control study in China.

Environ Int 2021 Jul 24;157:106770. Epub 2021 Jul 24.

Institute of Reproductive and Child Health, Peking University/ Key Laboratory of Reproductive Health, National Health Commission of the People's Republic of China, Beijing 100191, PR China; Department of Epidemiology and Biostatistics, School of Public Health, Peking University, Beijing 100191, PR China.

Background: Exposure to environmental endocrine disruptors (EDCs) may lead to abnormal glucose metabolism and, potentially, gestational diabetes mellitus (GDM).

Objective: We investigated the association between five endocrine-disrupting heavy metals (EDHMs), i.e., arsenic (As), cadmium (Cd), lead (Pb), mercury (Hg), and tin (Sn), in maternal hair and the risk of GDM.

Methods: We conducted a nested case-control study including 335 GDM cases and 343 controls without GDM based on a prospective birth cohort established in Beijing, China. Concentrations of EDHMs were analyzed in maternal hair. Log-binomial regression and multiple linear regression were used to estimate the associations between the hair concentrations of single metals and the risk of GDM, while weighted quantile sum (WQS) regression for their mixed effects.

Results: The median concentrations of Hg (0.442 vs. 0.403 μg/g) and Sn (0.171 vs. 0.140 μg/g) in the case group were significantly higher than those in the control group. No differences were found between the two groups for the other three metals. After adjusting for confounders, the prevalence ratio (PR; highest vs. lowest tertile) of GDM risk for Hg was 1.27 (95% confidence interval [CI]: 1.05-1.54), while that for Sn was 1.26 (95% CI: 1.04-1.53). Among women with a body mass index < 24 kg/m, the PR (highest vs. lowest tertile) of GDM for Sn was 1.38 (95% CI: 1.09-1.75). The effect of exposure to the five EDHMs on the risk of GDM was estimated by WQS regression: Sn and Hg made the largest contributions to the WQS index (40.9% and 40.3%, respectively).

Conclusion: High maternal levels of EDHMs, particularly Sn and Hg, may promote the development of GDM.
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http://dx.doi.org/10.1016/j.envint.2021.106770DOI Listing
July 2021

Serum zinc concentration and risk of adverse outcomes to in vitro fertilization and embryo transfer: A prospective cohort study in northern China.

Sci Total Environ 2021 Oct 10;792:148405. Epub 2021 Jun 10.

Center of Reproductive Medicine, Peking University People's Hospital, Beijing 100044, PR China. Electronic address:

Zinc (Zn) plays an important role in female reproductive health. Few studies have currently assessed the effects of female Zn level on the outcome of in vitro fertilization-embryo transfer (IVF-ET). This study investigated the association between serum Zn concentration and IVF-ET outcomes, and the potential effects of some lifestyles on this association. A prospective cohort study design was adopted, and 305 women undergoing IVF-ET were recruited from two cities, Beijing and Shandong, in northern China. Fasting blood specimens were obtained on the day prior to the first treatment cycle. A questionnaire was used to collect demographic characteristics and lifestyle information. Serum Zn concentration was measured using inductively coupled plasma-mass spectrometry. Female serum Zn levels in Beijing center were found to be significantly higher than those in Shandong center. Women who failed to achieve clinical pregnancy had significantly lower Zn concentrations among Shandong subjects, but not in Beijing or the total participants in both centers. For Beijing participants, no statistically significant associations were found between Zn concentrations and the failure risk of IVF-ET [adjusted relative risk (aRR) = 0.65, 95% confidence interval (CI): 0.37-1.15]. For Shandong participants, lower Zn concentrations (< 610.3 ng/mL) were associated with a 66% increased risk of IVF-ET failure (aRR = 1.66, 95% CI: 1.10-2.51). Also, significantly positive correlations were observed between Zn concentrations and the habitual consumption of two food types, including fresh vegetables and beans or bean products, but this was not the case in Beijing. It was concluded that the effect of serum Zn concentrations on IVF-ET outcome may vary by the geographic location. Lower Zn levels might be a risk factor for IVF-ET failure among Shandong women, which can be addressed by adjusting the food intakes. These findings have implications for human infertility treatment and public health problem addressing.
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http://dx.doi.org/10.1016/j.scitotenv.2021.148405DOI Listing
October 2021

Associations between blood heavy metal(loid)s and serum heme oxygenase-1 in pregnant women: Do their distribution patterns matter?

Environ Pollut 2021 Oct 29;286:117249. Epub 2021 Apr 29.

Institute of Reproductive and Child Health, Peking University/ Key Laboratory of Reproductive Health, National Health Commission of the People's Republic of China, Beijing, 100191, PR China; Department of Epidemiology and Biostatistics, School of Public Health, Peking University, Beijing, 100191, PR China.

The relationship between heavy metal(loid)s exposure and oxidative stress damage is a matter of research interest. Our study aimed to investigate the distribution patterns of the nine heavy metal(loid)s in blood of pregnant women, including four toxic heavy metal(loid)s [arsenic (As), cadmium (Cd), lead (Pb) and mercury (Hg)] and five typical heavy metal(loid)s [manganese (Mn), cobalt (Co), copper (Cu), zinc (Zn), and selenium (Se)] in blood. Blood samples of 348 women were collected and their concentrations in the serum (sr) and blood cells (bc) were measured, as well as serum heme oxygenase-1 (HO-1) (an oxidative stress marker). Total blood (tb) concentrations of these metal(loid)s and serum-to-blood cell concentration ratios (sr/bc) were further calculated. We found Cu mainly accumulated in the serum compared to the blood cells with Cu = 2.30, whereas Co, Se, and As evenly distributed between these two fractions. Other metal(loid)s mainly concentrated in the blood cells. Co, Cu, Cu, Mn, Zn, Cd, Co, Cu, Mn, Zn, Cd, and Cu were negatively associated with serum HO-1, whereas As, As, As, Zn, Cd, and Hg were positively, indicating of their potential toxicity. We concluded that the distribution patterns of blood heavy metal(loid)s, in particular for Cd, Hg and Zn, which either increased in serum or decreased in blood cells, might be associated with elevated serum oxidative stress, should be considered in environmental health assessments.
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http://dx.doi.org/10.1016/j.envpol.2021.117249DOI Listing
October 2021

Distribution of mercury in serum and blood cells and risk of spontaneous preterm birth: A nested case-control study in China.

Ecotoxicol Environ Saf 2021 Jul 20;217:112228. Epub 2021 Apr 20.

Institute of Geographic Sciences and Natural Resources Research, CAS, Beijing 100101, PR China. Electronic address:

The relationship between maternal mercury (Hg) intake and the risk of spontaneous preterm birth (SPB) remains unclear. We conducted a nested case-control study from a prospective cohort in Shanxi Province, China, to explore their associations. In total, 126 pregnant women with SPB (cases) and 348 controls with term delivery were included. We measured the Hg concentrations in their serum (Hg) and blood cell (Hg) fractions and calculated the concentration ratio of Hg in serum to Hg in blood cells (Hg). We found that only the Hg in the case group was slightly higher than that in control group. The OR of Hg associated with SPB risk was 1.57 [95%CI: 0.99-2.46] with adjusting confounders. After stratification by sampling time, the association above was only statistically significant in the first trimester. High Hg may increase the risk of SPB in the first trimester among women with relatively low Hg exposure.
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http://dx.doi.org/10.1016/j.ecoenv.2021.112228DOI Listing
July 2021

Contribution of Temperature Increase to Restrain the Transmission of COVID-19.

Innovation (N Y) 2021 Feb 16;2(1):100071. Epub 2020 Dec 16.

Institute of Reproductive and Child Health, Peking University/ Key Laboratory of Reproductive Health, National Health Commission of the People's Republic of China, Beijing 100191, P. R. China.

The COVID-19 outbreak has already become a global pandemic and containing this rapid worldwide transmission is of great challenge. The impacts of temperature and humidity on the COVID-19 transmission rate are still under discussion. Here, we elucidated these relationships by utilizing two unique scenarios, repeated measurement and natural experiment, using the COVID-19 cases reported from January 23 - February 21, 2020, in China. The modeling results revealed that higher temperature was most strongly associated with decreased COVID-19 transmission at a lag time of 8 days. Relative humidity (RH) appeared to have only a slight effect. These findings were verified by assessing SARS-CoV-2 infectivity under the relevant conditions of temperature (4°C-37°C) and RH (> 40%). We concluded that temperature increase made an important, but not determined, contribution to restrain the COVID-19 outbreak in China. It suggests that the emphasis of other effective controlling polices should be strictly implemented to restrain COVID-19 transmission in cold seasons.
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http://dx.doi.org/10.1016/j.xinn.2020.100071DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7834433PMC
February 2021

Association between tea drinking and plasma folate concentration among women aged 18-30 years in China.

Public Health Nutr 2020 Dec 15:1-8. Epub 2020 Dec 15.

Institute of Reproductive and Child Health/National Health Commission Key Laboratory of Reproductive Health, Peking University Health Science Center, Beijing100191, China.

Objective: Association was found between tea and neural tube defects. However, few studies investigated the relationship between tea consumption and blood folate levels. We aimed to investigate the association between tea consumption and plasma folate concentrations among women aged 18-30 years in different ethnicities of China.

Design: Data were obtained from a national cross-sectional study conducted from 2005 to 2006 of women aged 18-30 years in China. Socio-demographic characteristics and lifestyle were obtained from a questionnaire. Dietary folate intake was determined by 24-h dietary recall. Plasma folate concentrations were measured by a microbiological assay. Multiple linear regression model was used to calculate partial regression coefficients after adjusting for confounding factors.

Setting: Nine provinces or autonomous regions in China.

Participants: A total of 2932 women aged 18-30 years in China.

Results: After stratifying by ethnicity and tea type, tea consumption was significantly positively associated with plasma folate levels in Han women who drank unfermented tea weekly (β = 0·067, and P = 0·037) or daily (β = 0·119, and P = 0·031) and in Uighur women who drank fermented tea weekly (β = 0·325, and P = 0·028). For women who drank unfermented tea in Han ethnicity, weekly and daily tea drinkers had 6·77 % (95 % CI: 6·36 %, 7·21 %) and 7·13 % (95 % CI: 6·40 %, 7·96 %) increase in plasma folate concentration compared with no tea drinkers.

Conclusions: There is a suggestion of possible positive association between unfermented tea drinking in Han ethnicity and plasma folate concentrations, for Chinese women aged 18-30 years. The relationship between tea drinking in other ethnic groups and plasma folate still needs to be further explored.
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http://dx.doi.org/10.1017/S1368980020004851DOI Listing
December 2020

Environmental complex exposure and the risk of influenza-like illness among housewives: A case study in Shanxi Province, China.

Ecotoxicol Environ Saf 2020 May 9;194:110405. Epub 2020 Mar 9.

Reproductive Medical Center, Peking University People's Hospital, Beijing, 100044, PR China. Electronic address:

The association between environmental pollution and risk of influenza-like illness (ILI) among general population has been reported. However, the relationships between the individual pollutants and ILI risk are still under discussion. Our study aimed to explore the associations of the typical environmental polycyclic aromatic hydrocarbons (PAHs) and metal(loid)s with ILI risk among women population. We carried out a cross-sectional study and included a total of 396 housewives in Shanxi Province, China. The information on their general characteristics and ILI frequency was collected by questionnaire. We collected their hair samples and analyzed the concentrations of PAHs and various metal(loid)s. The results indicated that only acenaphthylene concentration of the nine detected PAH congeners in the hair was significantly associated with ILI risk with adjusted odds ratio (AOR) and 95% confidence interval (95% CI) of 0.58 (0.38 - 0.91). Among the concerned 4 toxic metal(loid)s and 15 rare earth elements, only the hair concentration of arsenic had a positive dose-response relationship with ILI risk. In addition, we found that there were negative dose-response associations of the three essential trace elements (i.e. chromium, cobalt, and nickel), and four essential alkaline earth elements (i.e. magnesium, calcium, strontium, barium) with ILI risk. It was concluded that the environmental exposure to certain compounds of housewives may contribute to their ILI development.
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http://dx.doi.org/10.1016/j.ecoenv.2020.110405DOI Listing
May 2020

External interference from ambient air pollution on using hair metal(loid)s for biomarker-based exposure assessment.

Environ Int 2020 04 24;137:105584. Epub 2020 Feb 24.

Institute of Reproductive and Child Health, Peking University/Key Laboratory of Reproductive Health, National Health Commission of the People's Republic of China, Beijing 100191, PR China; Department of Epidemiology and Biostatistics, School of Public Health, Peking University, Beijing 100191, PR China. Electronic address:

Hair metal(loid)s are often measured as biomarkers to evaluate population internal exposure, however, hair samples could be easily contaminated by ambient particulate matter (PM) pollution. Here, we evaluated the potential external interference from ambient PM pollution on using hair metal(loid)s for population biomarker-based exposure assessment. The raw hair samples were strictly washed and placed under various indoor and outdoor scenarios for ~6 months at sites with high PM pollution. The contaminated hair was then washed using the same method. A total of 33 hair elements were quantified by inductively coupled plasma-mass spectrometry. The surface residual PM on hair after washing was observed by scanning electron microscopy. In addition, we chose a practical exposure scenario including 77 housewives in Shanxi Province, China for validation. The results for the hair exposure experiment revealed that external contamination of some elements that had relatively high concentrations in hair was generally mild in both indoor and outdoor exposure scenarios (i.e., Zn, Mg, Se, Fe, Sr, Ti, Mn, Sn, Ge, U, Co, Mo, and As). A relatively higher external contamination of other elements (e.g., Al, Cr, Pb, Cd, Li, and most rare earth elements (REEs)) was observed, especially for those elements with relatively low hair concentrations (e.g., Cd, and REEs) in the outdoor environment. This finding was due mainly to some small ambient PM not being fully removed by the current washing strategy when the hair sample was heavily contaminated. However, results from practical exposure scenario of the housewives showed that there were overall no significant differences of hair metal(loid)s between the housewives using coal and clean energy for cooking. We concluded that the external interference on hair internal metal(loid) analysis could be negligible when hair was efficiently washed, especially for population with relatively longer indoor activities. It is therefore promising to use hair analysis for their population exposure assessment.
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http://dx.doi.org/10.1016/j.envint.2020.105584DOI Listing
April 2020

Simultaneous analysis of typical halogenated endocrine disrupting chemicals and metal(loid)s in human hair.

Sci Total Environ 2020 May 13;718:137300. Epub 2020 Feb 13.

Institute of Reproductive and Child Health, Peking University, Beijing 100191, PR China; Department of Epidemiology and Biostatistics, School of Public Health, Peking University, Beijing 100191, PR China.

Hair analysis has been an important approach in evaluating population exposure to various environmental factors. To meet the requirements of human environmental epidemiology studies, we aimed to develop an efficient method for simultaneous analysis of various metal(loid)s and some typical environmental halogenated endocrine disrupting chemicals (hEDCs) (i.e., polychlorinated biphenyls, polybrominated diphenyl ethers, and organochlorine pesticides, as well as some of their hydroxyl substituted metabolites) in a single hair sample. The hair was washed successively with surfactant solutions, methanol solvent, and deionized water to remove impurities attached to the hair surface. Efficiency was comprehensively compared among various washing strategies. The hair sample was further pulverized into fine powder with a median diameter (25th-75th percentile) of 8.6 (5.9-13.5) μm. The hair organic components were extracted by acetonitrile solvent and compared with the microwave-assisted extraction method. The hEDCs in the supernatant acetonitrile phase were quantified by gas chromatography-mass spectrometry, and the metal(loid)s in the precipitate hair were further analyzed by inductively coupled plasma mass spectrometry. Our developed method was further applied to analyze the hair samples of 165 pregnant women. The results showed that particles attached to the surface of the hair could not be washed off completely. However, we proposed a protocol framework to wash hair with relatively high efficience, which includes warm water incubation, and use of surfactant and organic solvent. The recoveries of the concerned hEDCs and metal(loid)s were overall in the range of 80% to 120%. For the women population, the method can efficiently recognize the typical exposure characteristics of the concerned hEDCs and metal(loid)s. Our study significantly ameliorated the deficiencies of the traditional hair washing strategy and developed an efficient method for simultaneous analysis of various metal(loid)s and hEDCs in a single hair sample. This method will provide important support for population complex exposure analysis and facilitate environmental exposome studies.
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http://dx.doi.org/10.1016/j.scitotenv.2020.137300DOI Listing
May 2020

Synergistic conversion of coal char and methane for syngas and carbon-based supercapacitor electrodes.

J Colloid Interface Sci 2020 Mar 7;562:235-243. Epub 2019 Dec 7.

School of Chemical Engineering, Northwest University, Xi'an 710069, China; Chemical Engineering Research Center of the Ministry of Education for Advanced Use Technology of Shanbei Energy, Shaanxi Research Center of Engineering Technology for Clean Coal Conversion, Northwest University, Xi'an 710069, China; International Science & Technology Cooperation Base of MOST for Clean Utilization of Hydrocarbon Resources, Collaborative Innovation Center for Development of Energy and Chemical Industry in Northern Shaanxi, Xi'an 710069, China.

A facile one-pot process for synergistic conversion of coal char and methane is conducted by employing KCO as the catalyst. Besides syngas production, valuable carbon products are obtained and used to serve for supercapacitor electrodes. Effect of the operating parameters (including the catalyst dosage, gas feed flow rate, reaction temperature and time) is evaluated on electrochemical performance of the as-prepared carbon. The appropriate surface and structural properties enable the prepared carbon electrode to have a remarkable capacitive performance, along with a specific capacitance up to 125 F/g at a scan rate of 5 mV/s and 133 F/g at a current density of 1 A/g. According to the potential capacitive contribution of the carbon species, the high capacitive performance is mainly attributed to formation and growth of abundant carbon fibers in the one-pot process.
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http://dx.doi.org/10.1016/j.jcis.2019.12.024DOI Listing
March 2020

The Association Among Social Support, Self-Efficacy, Use of Mobile Apps, and Physical Activity: Structural Equation Models With Mediating Effects.

JMIR Mhealth Uhealth 2019 09 25;7(9):e12606. Epub 2019 Sep 25.

Department of Social Medicine and Health Education, School of Public Health, Peking University, Beijing, China.

Background: Physical inactivity is a risk factor for chronic noncommunicable diseases. Insufficient physical activity has become an important public health problem worldwide. As mobile apps have rapidly developed, physical activity apps have the potential to improve the level of physical activity among populations.

Objective: This study aimed to evaluate the effect of physical activity apps on levels of physical activity among college students.

Methods: A Web-based questionnaire was used to survey college students in Beijing from December 27, 2017, to January 5, 2018. According to a previous survey, 43% of college students using physical activity apps and 36% of those who never used such apps achieved the physical activity recommendations. In this study, the sample size was calculated to be 500. The questionnaire consisted of 5 parts: the use of physical activity apps, sports habits, social support, self-efficacy, and social demographic information. Structural equation modeling was used to test the relationships between the use of physical activity apps, self-efficacy, social support, and level of physical activity.

Results: Of the 1245 participants, 384 college students (30.8%) used physical activity apps (in the past month). Of these 384 students, 191 (49.7%) gained new friends via the app. College students who were using physical activity apps had a higher level of physical activity and higher scores for social support and self-efficacy (P<.001) than those who did not use such apps. The use of physical activity apps significantly affected the mediating effect of physical activity level through social support (beta=.126; P<.001) and self-efficacy (beta=.294; P<.001). Gender played an important role in app use, self-efficacy, and physical activity in the mediation model: male users spent more time on physical activity and had higher self-efficacy scores (P<.001).

Conclusions: This study focused on college students in Beijing and found that the use of physical activity apps is associated with higher physical activity levels among these students. This effect is mainly through the mediation effect of social support and self-efficacy, rather than the direct effect of physical activity apps. The use of physical activity apps is associated with a higher social support level and higher self-efficacy score. Furthermore, a high social support level and high self-efficacy score are associated with higher physical activity levels.
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http://dx.doi.org/10.2196/12606DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6785721PMC
September 2019

Identification of Loci Controlling the Dwarfism Trait in the White Sailfin Molly () Using Genome-Wide Association Studies Based on Genotyping-By-Sequencing.

Genes (Basel) 2019 05 30;10(6). Epub 2019 May 30.

National Engineering Laboratory for Animal Breeding, Beijing Key Laboratory of Animal Genetic Improvement, College of Animal Science and Technology, China Agricultural University, Beijing 100193, China.

Dwarfism is a condition defined by low harvest weight in fish, but also results in strange body figures which may have potential for the selective breeding of new ornamental fish strains. The objectives of this study are to reveal the physiological causes of dwarfism and identify the genetic loci controlling this trait in the white sailfin molly. Skeletons of dwarf and normal sailfin mollies were observed by X-ray radioscopy and skeletal staining. Genome-wide association studies based on genotyping-by-sequencing (n = 184) were used to map candidate genomic regions associated with the dwarfism trait. Quantitative real-time PCR was performed to determine the expression level of candidate genes in normal (n = 8) and dwarf (n = 8) sailfin mollies. We found that the dwarf sailfin molly has a short and dysplastic spine in comparison to the normal fish. Two regions, located at NW_015112742.1 and NW_015113621.1, were significantly associated with the dwarfism trait. The expression level of three candidate genes, , and were significantly different between the dwarf and normal sailfin mollies in the hepatopancreas, with also showing significant differences in the vertebrae and showing significant differences in the muscle. This study identified genomic regions and candidate genes associated with the dwarfism trait in the white sailfin molly and would provide a reference to determine dwarf-causing variations.
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http://dx.doi.org/10.3390/genes10060418DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6628085PMC
May 2019

Potential effect of germanium exposure on the risk of influenza-like illness in housewives in Shanxi Province, China.

Sci Total Environ 2019 Sep 9;682:208-212. Epub 2019 May 9.

Institute of Reproductive and Child Health, Peking University/Key Laboratory of Reproductive Health, National Health Commission of the People's Republic of China, Beijing 100191, PR China; Department of Epidemiology and Biostatistics, School of Public Health, Peking University, Beijing 100191, PR China.

Few studies have examined the relationship between exposure to germanium (Ge) and the risk of influenza-like illness (ILI). Therefore, we investigated the association of Ge exposure and its interaction with single nucleotide polymorphisms (SNPs) related to Phase II metabolism on ILI risk among housewives in Shanxi Province, northern China. This cross-sectional study enrolled 373 housewives. Information on the housewives' characteristics and the frequency of ILI was collected by questionnaire. We analyzed the Ge concentrations in hair samples taken from near the scalp at the back of the head. Blood samples were used to identify SNPs related to Phase II metabolism. The results suggested that the hair Ge concentration was associated with ILI risk with an adjusted odds ratio and 95% confidence interval of 2.59 (1.61-4.19). A significant dose-response relationship was observed without or with adjusting for confounders. We did not observe any interaction effect between the hair Ge concentration and the SNPs on ILI risk. We found that high dietary consumption of meat and fried foods was positively correlated with the hair Ge concentration. Therefore, chronic Ge exposure may be a risk factor for an increased frequency of ILI in housewives.
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http://dx.doi.org/10.1016/j.scitotenv.2019.05.103DOI Listing
September 2019

An efficient method to simultaneously analyze multi-class organic pollutants in human serum.

Environ Pollut 2019 Aug 3;251:400-406. Epub 2019 May 3.

Institute of Reproductive and Child Health, Peking University/ Key Laboratory of Reproductive Health, National Health Commission of the People's Republic of China, Beijing, 100191, PR China; Department of Epidemiology and Biostatistics, School of Public Health, Peking University, Beijing, 100191, PR China.

The degree of population exposure to various organic pollutants (OPs), including polycyclic aromatic hydrocarbons, organochlorinated pesticides, polychlorinated biphenyls, and polybrominated diphenyl ethers, can be determined by measuring their concentrations in human serum. However, performing large-scale measurements with such a variety of compounds in serum is challenging in terms of efficiency and cost. We describe herein the development of a high-efficiency extraction and sample cleanup protocol for simultaneous and quantitative analyses of OPs using gas chromatography-mass spectrometry. OPs, together with crude lipid impurities, were extracted from human serum with a mixture of n-hexane and methyl tert-butyl ether. A disperse sorbent composed of primary secondary amine and C18 (PSA/C18) was used to roughly remove co-extracted impurities. A combined column of neutral silica gel and neutral alumina oxide (AlO/SiG) was then used for deep cleanup. For the removal of impurities, the overall performance of our protocol for the analysis of OPs in serum was comparable to that of traditional gel permeation chromatography (GPC) and dramatically better than that of PSA/C18, which is a frequently used QuEChERS (quick, easy, cheap, effective, rugged, safe) based method. While both the proposed protocol and GPC yielded recoveries of 80%-110% for four classes of OPs, our protocol consumed about 10 times less solvent, resulting in lower experimental expenses and a lower risk of contamination from residual OPs in the solvent and other supplies. In contrast to GPC, our protocol also permits efficient batch processing of serum samples, allowing for large sample sizes such as those encountered in epidemiological studies.
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http://dx.doi.org/10.1016/j.envpol.2019.05.008DOI Listing
August 2019

Long-range superharmonic Josephson current and spin-triplet pairing correlations in a junction with ferromagnetic bilayers.

Sci Rep 2016 Feb 19;6:21308. Epub 2016 Feb 19.

School of Physics and Telecommunication Engineering, Shaanxi University of Technology, Hanzhong 723001, China.

The long-range spin-triplet supercurrent transport is an interesting phenomenon in the superconductor/ferromagnet () heterostructure containing noncollinear magnetic domains. Here we study the long-range superharmonic Josephson current in asymmetric junctions. It is demonstrated that this current is induced by spin-triplet pairs  -  or  +  in the thick layer. The magnetic rotation of the particularly thin layer will not only modulate the amplitude of the superharmonic current but also realise the conversion between  -  and  + . Moreover, the critical current shows an oscillatory dependence on thickness and exchange field in the layer. These effect can be used for engineering cryoelectronic devices manipulating the superharmonic current. In contrast, the critical current declines monotonically with increasing exchange field of the layer, and if the layer is converted into half-metal, the long-range supercurrent is prohibited but still exists within the entire region. This phenomenon contradicts the conventional wisdom and indicates the occurrence of spin and charge separation in present junction, which could lead to useful spintronics devices.
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http://dx.doi.org/10.1038/srep21308DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4759579PMC
February 2016
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