Huizhen Sun

AgInSbTe memristor with gradual resistance tuning

A chalcogenide material with Ag/Ag5In5Sb60Te30/Ag structure was proposed as a memristor. Reproducible gradual resistance tuning in bipolar/unipolar modes was demonstrated. The resistance variation was tuned more precisely by controlling the polarity, the amplitude, the width, and the number of applied voltage pulses. The bipolar memristive switch was attributed to the coexistence of intrinsic space charge limited conduction and extrinsic electrochemical metallization effect. Moreover, the unipolar gradual resistance tuning reconfirmed the electrochemical metallization effect. The gradual resistance tuning characteristics will promote this memristor to potential application in mimicking biological plastic synapses.

Urinary Polycyclic Aromatic Hydrocarbon Metabolites and Altered Lung Function in Wuhan, China

RATIONALE Exposure to polycyclic aromatic hydrocarbons (PAHs) has been associated with adverse effects on the respiratory system. However, the association between internal levels of PAH metabolites and lung function levels remains unclear. OBJECTIVES We investigated the relationships between urinary PAH metabolite concentrations and lung function levels in a general Chinese population. METHODS Lung function and 12 urinary PAH metabolites were measured in 2,747 participants from the Wuhan-Zhuhai cohort in China. Associations between urinary PAH metabolites and lung function were analyzed by linear mixed models. We also investigated associations among urinary PAH metabolite concentrations, traffic exposure time, and dietary PAH exposure. MEASUREMENTS AND MAIN RESULTS We found significant associations between increased levels of urinary PAH metabolites and reduced lung function. Each 1-U increase in log-transformed levels of 2-hydroxynaphthalene, 9-hydroxyfluorene, 2-hydroxyfluorene, 4-hydroxyphenanthrene, 9-hydroxyphenanthrene, 3-hydroxyphenanthrene, 1-hydroxyphenanthrene, 2-hydroxyphenanthrene, 1-hydroxypyrene, or total urinary PAH metabolites was associated with a 23.79-, 19.36-, 41.76-, 36.87-, 33.47-, 27.37-, 39.53-, 34.35-, 25.03-, or 37.13-ml reduction in FEV1, respectively (all P < 0.05). Each 1-U increase in 2-hydroxynaphthalene, 2-hydroxyfluorene, 4-hydroxyphenanthrene, 1-hydroxyphenanthrene, 2-hydroxyphenanthrene, or total urinary PAH metabolites was associated with a 24.39-, 33.90-, 27.15-, 28.56-, 27.46-, or 27.99-ml reduction in FVC, respectively (all P < 0.05). The total urinary PAH metabolites concentration was positively associated with both traffic exposure time and dietary PAH exposure among nonsmokers. CONCLUSIONS Total and specific urinary PAH metabolites were associated with lung function reduction in a general Chinese population. Further studies are needed to investigate the potential mechanism by which PAHs induces lung function reduction.

Dose-response relationship between polycyclic aromatic hydrocarbon metabolites and risk of diabetes in the general Chinese population

The incidence of diabetes is increasing rapidly in Chinese population, and it has been postulated that environmental factors may play a role in the etiology of diabetes. Therefore, we aimed to investigate the association between PAHs exposure and risk of diabetes in a community-based population of 2824 participants with completed questionnaires, measurements of biochemical indices, and urinary PAHs metabolites. We found that elevated urinary PAHs metabolites were associated, in a dose-dependent manner, with increased risk of diabetes. Particularly, these associations were more evident in subjects who were female, less than 55 years old, nonsmokers, and normal weight. In addition, there was a modest improvement in diabetes discrimination of prediction models when incorporating certain PAHs metabolites into conventional risk factors (CRF). Overall, our data suggested that there may be a dose-dependent relationship between PAHs metabolites and risk of diabetes among general Chinese population.

A community study of the effect of polycyclic aromatic hydrocarbon metabolites on heart rate variability based on the Framingham risk score

Objectives To investigate the effects of the urinary metabolite profiles of background exposure to the atmospheric pollutants polycyclic aromatic hydrocarbon (PAH) and Framingham risk score (FRS), which assesses an individuals cardiovascular disease risk, on heart rate variability (HRV). Methods The study conducted from April to May 2011 in Wuhan, China, included 1978 adult residents with completed questionnaires, physical examinations, blood and urine samples, and 5-min HRV indices (including SD of all normal to normal intervals (SDNN), root mean square successive difference (rMSSD), low frequency (LF), high frequency (HF) and their ratio (LF/HF), and total power) obtained from 3-channel Holter monitor. 12 urinary PAH metabolites were measured by gas chromatography–mass spectrometry. FRS was calculated by age, sex, lipid profiles, blood pressure, diabetes and smoking status. Linear regression models were constructed after adjusting for potential confounders. Results Elevated total concentration of hydroxynaphthalene (ΣOHNa) was significantly associated, in a dose–responsive manner, with decreased SDNN and LF/HF (ptrend=0.014 and 0.007, respectively); elevated total concentration of hydroxyfluorene (ΣOHFlu) was significantly associated with reduced SDNN, LF and LF/HF (ptrend=0.027, 0.003, and <0.0001, respectively); and elevated total concentration of all PAH metabolites (ΣOH-PAHs) was associated with decreased LF and LF/HF (ptrend=0.005 and <0.0001, respectively). Moreover, increasing quartiles of FRS were significantly associated with decreased HRV indices, except LF/HF (all ptrend<0.0001). Interestingly, individuals in low-risk subgroups had greater decreases in SDNN, LF and LF/HF in relation to ΣOH-PAHs, ΣOHNa and ΣOHFlu than those in high-risk subgroups (all p<0.05). Conclusions Environmental PAH exposure may differentially affect HRV based on individual coronary risk profiles.

Genome-Wide Analysis of DNA Methylation and Cigarette Smoking in a Chinese Population.

Background: Smoking is a risk factor for many human diseases. DNA methylation has been related to smoking, but genome-wide methylation data for smoking in Chinese populations is limited. Objectives: We aimed to investigate epigenome-wide methylation in relation to smoking in a Chinese population. Methods: We measured the methylation levels at > 485,000 CpG sites (CpGs) in DNA from leukocytes using a methylation array and conducted a genome-wide meta-analysis of DNA methylation and smoking in a total of 596 Chinese participants. We further evaluated the associations of smoking-related CpGs with internal polycyclic aromatic hydrocarbon (PAH) biomarkers and their correlations with the expression of corresponding genes. Results: We identified 318 CpGs whose methylation levels were associated with smoking at a genome-wide significance level (false discovery rate < 0.05), among which 161 CpGs annotated to 123 genes were not associated with smoking in recent studies of Europeans and African Americans. Of these smoking-related CpGs, methylation levels at 80 CpGs showed significant correlations with the expression of corresponding genes (including RUNX3, IL6R, PTAFR, ANKRD11, CEP135 and CDH23), and methylation at 15 CpGs was significantly associated with urinary 2-hydroxynaphthalene, the most representative internal monohydroxy-PAH biomarker for smoking. Conclusion: We identified DNA methylation markers associated with smoking in a Chinese population, including some markers that were also correlated with gene expression. Exposure to naphthalene, a byproduct of tobacco smoke, may contribute to smoking-related methylation. Citation: Zhu X, Li J, Deng S, Yu K, Liu X, Deng Q, Sun H, Zhang X, He M, Guo H, Chen W, Yuan J, Zhang B, Kuang D, He X, Bai Y, Han X, Liu B, Li X, Yang L, Jiang H, Zhang Y, Hu J, Cheng L, Luo X, Mei W, Zhou Z, Sun S, Zhang L, Liu C, Guo Y, Zhang Z, Hu FB, Liang L, Wu T. 2016. Genome-wide analysis of DNA methylation and cigarette smoking in Chinese. Environ Health Perspect 124:966–973; http://dx.doi.org/10.1289/ehp.1509834

Intrinsic memristance mechanism of crystalline stoichiometric Ge2Sb2Te5

The bipolar memristive switching of stoichiometric crystalline Ge2Sb2Te5 (GST) thin film has been demonstrated. In contrast to the filamentary switching reported previously for a GST memristor, the intrinsic memristance is interpreted as arising from a trap-associated space-charge limited current mechanism, which is confirmed by the frequency-dependent resistance and capacitance. The contributions of charge trapping in grain defects and grain boundary defects are analyzed, and the latter ones may dominate the resistance variation. Unraveling the intrinsic memristance of GST will help us further understand the conduction mechanism of chalcogenides and promote the design of future nonvolatile memory and neuromorphic devices.

Genome-Wide Analysis of DNA Methylation and Acute Coronary Syndrome.

Rationale: Acute coronary syndrome (ACS) is a leading cause of death worldwide. Immune functions play a vital role in ACS development; however, whether epigenetic modulation contributes to the regulation of blood immune cells in this disease has not been investigated. Objective: We conducted an epigenome-wide analysis with circulating immune cells to identify differentially methylated genes in ACS. Methods and Results: We examined genome-wide methylation of whole blood in 102 ACS patients and 101 controls using HumanMethylation450 array, and externally replicated significant discoveries in 100 patients and 102 controls. For the replicated loci, we further analyzed their association with ACS in 6 purified leukocyte subsets, their correlation with the expressions of annotated genes, and their association with cardiovascular traits/risk factors. We found novel and reproducible association of ACS with blood methylation at 47 cytosine-phosphoguanine sites (discovery: false discovery rate <0.005; replication: Bonferroni corrected P<0.05). The association of methylation levels at these cytosine-phosphoguanine sites with ACS was further validated in at least 1 of the 6 leukocyte subsets, with predominant contributions from CD8+ T cells, CD4+ T cells, and B cells. Blood methylation of 26 replicated cytosine-phosphoguanine sites showed significant correlation with expressions of annotated genes (including IL6R, FASLG, and CCL18; P<5.9×10−4), and differential gene expression in case versus controls corroborated the observed differential methylation. The replicated loci suggested a role in ACS-relevant functions including chemotaxis, coronary thrombosis, and T-cell–mediated cytotoxicity. Functional analysis using the top ACS-associated methylation loci in purified T and B cells revealed vital pathways related to atherogenic signaling and adaptive immune response. Furthermore, we observed a significant enrichment of the replicated cytosine-phosphoguanine sites associated with smoking and low-density lipoprotein cholesterol (Penrichment⩽1×10−5). Conclusions: Our study identified novel blood methylation alterations associated with ACS and provided potential clinical biomarkers and therapeutic targets. Our results may suggest that immune signaling and cellular functions might be regulated at an epigenetic level in ACS.

The dose-response association of urinary metals with altered pulmonary function and risks of restrictive and obstructive lung diseases: a population-based study in China.

Objective Reduced pulmonary function is an important predictor of environment-related pulmonary diseases; however, evidence of an association between exposures to various metals from all possible routes and altered pulmonary function is limited. We aimed to investigate the association of various metals in urine with pulmonary function, restrictive lung disease (RLD) and obstructive lung disease (OLD) risks in the general Chinese population. Design A cross-sectional investigation in the Wuhan cohort population. Setting A heavily polluted Chinese city. Participants A total of 2460 community-living Chinese adults from the Wuhan cohort were included in our analysis. Main outcome measures Spirometric parameters (FVC, forced vital capacity; FEV1, forced expiratory volumes in 1 s; FEV1/FVC ratio), RLD and OLD. Results The dose–response associations of pulmonary function, and RLD and OLD, with 23 urinary metals were assessed using regression analysis after adjusting for potential confounders. The false discovery rate (FDR) method was used to correct for multiple hypothesis tests. Our results indicated that there were positive dose–response associations of urinary iron with FEV1 and FEV1/FVC ratio, vanadium with FEV1, and copper and selenium with FEV1/FVC ratio, while a negative dose–response association was observed between urinary lead and FEV1/FVC ratio (all p<0.05). After additional adjusting for multiple comparisons, only iron was dose dependently related to FEV1/FVC ratio (FDR adjusted p<0.05). The dose–response association of iron and lead, with decreased and increased chronic obstructive pulmonary disease risk, respectively, was also observed (both p<0.05). Additionally, we found significant association of urinary zinc with RLD and interaction effects of smoking status with lead on FEV1/FVC, and with cadmium on FVC and FEV1. Conclusions These results suggest that multiple urinary metals are associated with altered pulmonary function, and RLD and OLD prevalences.

Combined effect of urinary monohydroxylated polycyclic aromatic hydrocarbons and impaired lung function on diabetes.

Associations of type 2 diabetes with exposure to polycyclic aromatic hydrocarbons and reduced lung function have been reported. The aim of the present study was to investigate effect of reduced lung function and exposure to background PAHs on diabetes. A total of 2730 individuals were drawn from the Wuhan-Zhuhai (WHZH) Cohort Study (n=3053). Participants completed physical examination, measurement of lung function and urinary monohydroxylated polycyclic aromatic hydrocarbons (OH-PAHs). Risk factors for type 2 diabetes were identified by multiple logistic regression analysis, and the presence of additive interaction between levels of urinary OH-PAHs and lower lung function was evaluated by calculation of the relative excess risk due to interaction (RERI) and attributable proportion due to interaction (AP). Urinary OH-PAHs levels was positively associated with type 2 diabetes among individuals with impaired lung function (p<0.05). Forced expiratory volume in one second (FEV1, odd ratio (OR): 0.664, 95% confidence interval (CI): 0.491-0.900) and forced vital capacity (FVC, OR: 0.693, 95% CI: 0.537-0.893) were negatively associated with diabetes among individuals. Additive interaction of higher urinary levels of OH-PAHs and lower FVC (RERI: 0.679, 95% CI: 0.120-1.238); AP: 0.427, 95% CI: 0.072-0.782) was associated with diabetes. Exposure to background PAHs was related to diabetes among individuals with lower lung function. Urinary levels of OH-PAHs and reduced lung function had an additive effect on diabetes.

Housing characteristics in relation to exhaled nitric oxide in China.

OBJECTIVE To investigate indoor factors affecting fractional exhaled nitric oxide (FeNO) in community residents. METHODS A total of 2404 adults (865 men, 1539 women, mean age 51.7 ± 13.3 years) were recruited to the study. Factors affecting FeNO were analyzed by multiple linear regression analysis. RESULTS Participants without a kitchen exhaust fan/hood had higher FeNO (GM: 10.21%, 95% CI: 4.18%-16.59%). Participants engaged in home cooking who used only liquefied petroleum gas had higher FeNO (GM: 5.75%, 95% CI: 0.10%-11.73%) compared to those using natural gas for residential (home) cooking. CONCLUSION Nonuse of a kitchen exhaust fan/hood and use of liquefied petroleum gas among persons engaged in home cooking were associated with higher FeNO levels.