Reducing Indoor Particulate Air Pollution Improves Student Test Scores: A Randomized Double-Blind Crossover Study

Short-term exposure to air pollution is associated with a decline in cognitive function. Standardized test scores have been employed to evaluate the effects of air pollution exposure on cognitive performance. Few studies aimed to prove whether air pollution is responsible for reduced test scores; none have implemented a "gold-standard" method for assessing the association such as a randomized, double-blind intervention. This study used a "gold-standard" method─randomized, double-blind crossover─to assess whether reducing short-term indoor particle concentrations results in improved test scores in college students in Tianjin, China. Participants (n = 162) were randomly assigned to one of two similar classrooms and completed a standardized English test on two consecutive weekends. Air purifiers with active or sham (i.e., filter removed) particle filtration were placed in each classroom. The filtration mode was switched between the two test days. Linear mixed-effect models were used to evaluate the effect of the intervention mode on the test scores. The results show that air purification (i.e., reducing PM) was significantly associated with increases in the z score for combined (0.11 [95%CI: 0.02, 0.21]) and reading (0.11 [95%CI: 0.00, 0.22]) components. In conclusion, a short-term reduction in indoor particle concentration led to improved test scores in students, suggesting an improvement in cognitive function.

Ascertaining sensitive exposure biomarkers of various metal(loid)s to embryo implantation

Close relationships exist between metal(loid)s exposure and embryo implantation failure (EIF) from animal and epidemiological studies. However, there are still inconsistent results and lacking of sensitive metal(loid) exposure biomarkers associated with EIF risk. We aimed to ascertain sensitive metal(loid) biomarkers to EIF and provide potential biological explanations. Candidate metal(loid) biomarkers were measured in the female hair (FH), female serum (FS), and follicular fluid (FF) with various exposure time periods. An analytical framework was established by integrating epidemiological association results, comprehensive literature searching, and knowledge-based adverse outcome pathway (AOP) networks. The sensitive biomarkers of metal(loid)s along with potential biological pathways to EIF were identified in this framework. Among the concerned 272 candidates, 45 metal(loid)s biomarkers across six time periods and three biomatrix were initially identified by single-metal(loid) analyses. Two biomarkers with counterfactual results according to literature summary results were excluded, and a total of five biomarkers were further determined from 43 remained candidates in mixture models. Finally, four sensitive metal(loid) biomarkers were eventually assessed by overlapping AOP networks information, including Se and Co in FH, and Fe and Zn in FS. AOP networks also identified key GO pathways and proteins involved in regulation of oxygen species biosynthetic, cell proliferation, and inflammatory response. Partial dependence results revealed Fe in FS and Co in FH at their low levels might be potential sensitive exposure levels for EIF. Our study provided a typical framework to screen the crucial metal(loid) biomarkers and ascertain that Se and Co in FH, and Fe and Zn in FS played an important role in embryo implantation.

Critical windows of greenness exposure during preconception and gestational periods in association with birthweight outcomes

Few studies have examined the association between greenness exposure and birth outcomes. This study aims to identify critical exposure time windows during preconception and pregnancy for the association between greenness exposure and birth weight. A cohort of 13 890 pregnant women and newborns in Shanghai, China from 2016-2019 were included in the study. We assessed greenness exposure using Normalized Difference Vegetation Index (NDVI) during the preconception and gestational periods, and evaluated the association with term birthweight, birthweight z-score, small-for-gestational age, and large-for-gestational age using linear and logistic regressions adjusting for key maternal and newborn covariates. Ambient temperature, relative humidity, ambient levels of fine particles (PM2.5) and nitrogen dioxide (NO2) assessed during the same period were adjusted for as sensitivity analyses. Furthermore, we explored the potential different effects by urbanicity and park accessibility through stratified analysis. We found that higher greenness exposure at the second trimester of pregnancy and averaged exposure during the entire pregnancy were associated with higher birthweight and birthweight Z-score. Specifically, a 0.1 unit increase in second trimester averaged NDVI value was associated with an increase in birthweight of 10.2 g (95% CI: 1.8-18.5 g) and in birthweight Z-score of 0.024 (0.003-0.045). A 0.1 unit increase in an averaged NDVI during the entire pregnancy was associated with 10.1 g (95% CI: 1.0-19.2 g) increase in birthweight and 0.025 (0.001-0.048) increase in birthweight Z-score. Moreover, the associations were larger in effect size among urban residents than suburban residents and among residents without park accessibility within 500 m compared to those with park accessibility within 500 m. Our findings suggest that increased greenness exposure, particularly during the second trimester, may be beneficial to birth weight in a metropolitan area.

Ambient PM2.5-bound polycyclic aromatic hydrocarbons (PAHs) associated with pro-thrombotic biomarkers among young healthy adults: A 16 times repeated measurements panel study

Studies have shown that the cardio/cerebrovascular toxicity of ambient PM2.5 is related to its bound polycyclic aromatic hydrocarbons (PAHs). Currently, only a few studies have reported the relationship between PM2.5-bound PAHs and promoted blood coagulation and thrombosis, but there isn't a consistent conclusion. Therefore, we conducted a prospective panel study to investigate the association. Thirty-three young healthy adults participated in sixteen repeated visits from 2014 to 2018 in Tianjin, China. During each visit, three pro-thrombotic biomarkers: ADAMTS13 (a disintegrin and metalloproteinase with thrombospondin motif 13), D-dimer and Myeloperoxidase (MPO) were measured. Before each visit, ambient PM2.5 samples were daily collected for one week. Sixteen PAHs were determined using Gas Chromatography-Mass Spectrometer, and the positive matrix factorization (PMF) model was applied to identify the sources. Linear mixed-effects models were fitted to investigate the associations between PM2.5-bound PAHs exposure and the biomarkers. Thirteen time-metrics were defined to identify significant time points of PM2.5-bound PAHs' effects. We observed that the increase of PM2.5-bound PAHs exposure was significantly associated with reduced ADAMTS13, elevated D-dimer and MPO. At lag0, each 5.7 ng/m3 increase in Benzo[j]fluoranthene and per 3.4 ng/m3 increase Dibenz[a,h]anthracene could make a maximum change of -19.08 % in ADAMTS13 and 132.60 % in D-dimer. Additionally, per 16.43 ng/m3 increase in Chrysene could lead to a maximum elevation of 32.14 % in MPO at lag4. The PM2.5-bound PAHs often triggered more significant changes at lag 3,4 and 6. The ambient PM2.5-bound PAHs originated from six sources: coal combustion (43.10 %), biomass combustion (20.77 %), diesel emission (14.78 %), gasoline emission (10.95 %), industrial emission (7.58 %), and cooking emission (2.83 %). The greatest contributors to alterations in ADAMTS13, D-dimer and MPO are industrial emission (-48.43 %), biomass combustion (470.32 %) and diesel emission (13.14 %) at lag4. Our findings indicated that short-term exposure to ambient PM2.5-bound PAHs can induce alterations of pro-thrombotic biomarkers among healthy adults.

Personal Exposure to Source-Specific Particulate Polycyclic Aromatic Hydrocarbons and Systemic Inflammation: A Cross-Sectional Study of Urban-Dwelling Older Adults in China

Environmental exposure to ambient polycyclic aromatic hydrocarbons (PAHs) can disturb the immune response. However, the evidence on adverse health effects caused by exposure to PAHs emitted from specific sources among different vulnerable subpopulations is limited. In this cross-sectional study, we aimed to evaluate whether exposure to source-specific PAHs could increase systemic inflammation in older adults. The present study included community-dwelling older adults and collected filter samples of personal exposure to PM2.5 during the winter of 2011. Blood samples were collected after the PM2.5 sample collection. We analyzed PM2.5 bound PAHs and serum inflammatory cytokines (interleukin (IL)1β, IL6, and tumor necrosis factor alpha levels. The Positive Matrix Factorization model was used to identify PAH sources. We used a linear regression model to assess the relative effects of source-specific PM2.5 bound PAHs on the levels of measured inflammatory cytokines. After controlling for confounders, exposure to PAHs emitted from biomass burning or diesel vehicle emission was significantly associated with increased serum inflammatory cytokines and systemic inflammation. These findings highlight the importance of considering exposure sources in epidemiological studies and controlling exposures to organic materials from specific sources.

Identifying critical windows of air pollution exposure during preconception and gestational period on birthweight: a prospective cohort study

BACKGROUND

Few studies have assessed air pollution exposure association with birthweight during both preconception and gestational periods.

METHODS

Leveraging a preconception cohort consisting of 14220 pregnant women and newborn children in Shanghai, China during 2016-2018, we aim to assess associations of NO2 and PM2.5 exposure, derived from high-resolution spatial-temporal models, during preconception and gestational periods with outcomes including term birthweight, birthweight Z-score, small-for-gestational age (SGA) and large-for-gestational age (LGA). Linear and logistic regressions were used to estimate 3-month preconception and trimester-averaged air pollution exposure associations; and distributed lag models (DLM) were used to identify critical exposure windows at the weekly resolution from preconception to delivery. Two-pollutant models and children's sex-specific associations were explored.

RESULTS

After controlling for covariates, one standard deviation (SD) (11.5 μg/m3, equivalent to 6.1 ppb) increase in NO2 exposure during the second and the third trimester was associated with 13% (95% confidence interval: 2 - 26%) and 14% (95% CI: 1 - 29%) increase in SGA, respectively; and one SD (9.6 μg/m3) increase in PM2.5 exposure during the third trimester was associated with 15% (95% CI: 1 - 31%) increase in SGA. No association have been found for outcomes of birthweight, birthweight Z-score and LGA. DLM found that gestational weeks 22-32 were a critical window, when NO2 exposure had strongest associations with SGA. The associations of air pollution exposure tended to be stronger in female newborns than in male newborns. However, no significant associations of air pollution exposure during preconception period on birthweight outcomes were found.

CONCLUSION

Consistent with previous studies, we found that air pollution exposure during mid-to-late pregnancy was associated with adverse birthweight outcomes.

Cigarette Smoke Extract and Lipopolysaccharide Induce Pyroptosis in Pulmonary Microvascular Endothelial Cells of Rats

We studied the effect of cigarette smoke extract (CSE), LPS, or their combination on the activity and pyroptosis of pulmonary microvascular endothelial cells (PMVEC) in rats. PMVEC were cultured without treatment, with CSE in different concentrations (1-25%), with 20 ng/ml LPS, or with 20% CSE+20 ng/ml LPS. Cell viability was determined using the CCK8 kit, apoptosis was evaluated by flow cytometry, and cell morphology was evaluated using light microscopy. The content of IL-1β and IL-18 was measured by ELISA. CSE decreased cell viability in a dose-dependent manner. The morphology of cells in the CSE+LPS group showed the most significant cytomorphological changes and the highest pyroptosis rate. Flow cytometry showed that the apoptosis rates in the CSE and LPS groups were higher than in the control group, but the highest rate of apoptosis was revealed in the CSE+LPS group (p<0.01). The levels of IL-18 and IL-1β in the cell supernatant of the CSE, LPS, and CSE+LPS groups were significantly (p<0.01) increased in comparison with the control. These levels in the CSE+LPS group were higher (p<0.01) than in other groups. There were no differences between the CSE and LPS groups. Thus, the effect of CSE on cell viability is dose-dependent. Combined treatment with CSE+LPS can induce cell pyroptosis and increase the levels of inflammatory cytokines in PMVEC. These observations demonstrated that pyroptosis caused by CSE and LPS can play an important role in pulmonary vascular remodeling.

Integrating ambient carbonyl compounds provides insight into the constrained ozone formation chemistry in Zibo city of the North China Plain

Quantifying the impact of carbonyl compounds (carbonyls) on ozone (O₃) photochemical formation is crucial to formulating targeted O₃ mitigation strategies. To investigate the emission source of ambient carbonyls and their integrated observational constraint on the impact of O₃ formation chemistry, a field campaign was conducted in an industrial city (Zibo) of the North China Plain from August to September 2020. The site-to-site variations of OH reactivity for carbonyls were in accordance with the sequence of Beijiao (BJ, urban, 4.4 s^-1) > Xindian (XD, suburban, 4.2 s^-1) > Tianzhen (TZ, suburban, 1.6 s^-1). A 0-D box model (MCMv3.3.1) was applied to assess the O₃-precursor relationship influenced by measured carbonyls. It was found that without carbonyls constraint, the O₃ photochemical production of the three sites was underestimated to varying degrees, and the biases of overestimating the VOC-limited degree were also identified through a sensitivity test to NO_x emission changes, which may be associated with the reactivity of carbonyls. In addition, the results of the positive matrix factorization (PMF) model indicated that the main source of aldehydes and ketones was secondary formation and background (81.6% for aldehydes, 76.8% for ketones), followed by traffic emission (11.0% for aldehydes, 14.0% for ketones). Incorporated with the box model, we found that biogenic emission contributed the most to the O₃ production at the three sites, followed by traffic emission as well as industry and solvent usage. Meanwhile, the relative incremental reactivity (RIR) values of O₃ precursor groups from diverse VOC emission sources featured consistencies and differences at the three sites, which further highlights the importance of the synergetic mitigation of target O₃ precursors at regional and local scales. This study will help to provide targeted policy-guiding O₃ control strategies for other regions.

Ambient fine particulate matter exposures and oxidative protein damage in early pregnant women

The association between oxidative protein damage in early pregnant women and ambient fine particulate matter (PM_2.5) is unknown. We estimated the effect of PM_2.5 exposures within seven days before blood collection on serum 3-nitrotyrosine (3-NT) and advanced oxidation protein products (AOPP) in 100 women with normal early pregnancy (NEP) and 100 women with clinically recognized early pregnancy loss (CREPL). Temporally-adjusted land use regression model was applied for estimation of maternal daily PM_2.5 exposure. Daily nitrogen dioxide (NO₂) exposure of each participant was estimated using city-level concentrations of NO₂. Single-day lag effect of PM_2.5 was analyzed using multivariable linear regression model. Net cumulative effect and distributed lag effect of PM_2.5 and NO₂ within seven days were analyzed using distributed lag non-linear model. In all 200 subjects, the serum 3-NT were significantly increased with the single-day lag effects (4.72%-8.04% increased at lag 0-2), distributed lag effects (2.32%-3.49% increased at lag 0-2), and cumulative effect within seven days (16.91% increased). The single-day lag effects (7.41%-10.48% increased at lag 0-1), distributed lag effects (3.42%-5.52% increased at lag 0-2), and cumulative effect within seven days (24.51% increased) of PM_2.5 significantly increased serum 3-NT in CREPL group but not in NEP group. The distributed lag effects (2.62%-4.54% increased at lag 0-2) and cumulative effect within seven days (20.25% increased) of PM_2.5 significantly increased serum AOPP in early pregnant women before the coronavirus disease (COVID-19) pandemic but not after that, similarly to the effects of NO₂ exposures. In conclusion, PM_2.5 exposures were associated with oxidative stress to protein in pregnant women in the first trimester, especially in CREPL women. Analysis of NO₂ exposures suggested that combustion PM_2.5 was the crucial PM_2.5 component. Wearing masks may be potentially preventive in PM_2.5 exposure and its related oxidative protein damage.

Ambient fine particulate matter exposures and human early placental inflammation

The effect of fine particulate matter (PM_2.5) on human early maternal-fetal interface is unknown. We explored the association between maternal exposure to ambient PM_2.5 and inflammation in placental villus of 114 women with clinically recognized early pregnancy loss (CREPL) and 114 women with normal early pregnancy (NEP). Temporally-adjusted land use regression models were used to estimate maternal daily PM_2.5 exposure during pregnancy. Villus interleukin-1beta (IL-1β), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-α) were measured using multiplex cytokines detection platform. Single-day lag effect of PM_2.5 exposure within ten days before early placental villus collection was estimated using multivariable linear regression model. Distributed lag and net cumulative effects of PM_2.5 exposures within ten and 30 days before villus collection, as well as five single weeks during the periovulatory period, were estimated using distributed lag non-linear models. In all 228 subjects, after adjusting for group (CREPL or NEP), temporal confounders, and demographic characteristics, both single-day and distributed lag effects of PM_2.5 exposure at lag 8 significantly increased villus IL-6; distributed lag effects of PM_2.5 exposure in the first and second weeks before ovulation increased IL-1β, and PM_2.5 exposure in the third week after ovulation increased IL-6 and TNF-α. In CREPL, single-day lag effect significantly increased IL-1β (at lag 1), IL-6 (at lag 8), and TNF-α (at lag 5); distributed lag effect increased IL-6 (at lag 4-lag 8) and TNF-α (at lag 4-lag 6); and cumulative effect within ten days before villus collection increased IL-6. There was no statistically significant cumulative effect in NEP. In summary, maternal PM_2.5 exposure was associated with placental inflammation in human early pregnancy, particularly with increased villus IL-6 in CREPL. Whether maternal-fetal interface inflammation related to PM_2.5 exposure during the periovulatory period or later contributes to CREPL or other adverse pregnancy outcomes requires further study.

Observation of a Strongly Isospin-Mixed Doublet in ^{26}Si via β-Delayed Two-Proton Decay of ^{26}P

β decay of proton-rich nuclei plays an important role in exploring isospin mixing. The β decay of ^{26}P at the proton drip line is studied using double-sided silicon strip detectors operating in conjunction with high-purity germanium detectors. The T=2 isobaric analog state (IAS) at 13 055 keV and two new high-lying states at 13 380 and 11 912 keV in ^{26}Si are unambiguously identified through β-delayed two-proton emission (β2p). Angular correlations of two protons emitted from ^{26}Si excited states populated by ^{26}P β decay are measured, which suggests that the two protons are emitted mainly sequentially. We report the first observation of a strongly isospin-mixed doublet that deexcites mainly via two-proton decay. The isospin mixing matrix element between the ^{26}Si IAS and the nearby 13 380-keV state is determined to be 130(21) keV, and this result represents the strongest mixing, highest excitation energy, and largest level spacing of a doublet ever observed in β-decay experiments.

Short-term effects of the toxic component of traffic-related air pollution (TRAP) on lung function in healthy adults using a powered air purifying respirator (PAPR)

Short-term exposure to traffic-related air pollution (TRAP) are associated with reduced lung function. However, TRAP is a mixture of various gaseous pollutants and particulate matter (PM), and therefore it is unknown that which components of TRAP are responsible for the respiratory toxicity. Using a powered air-purifying respirator (PAPR), we conducted a randomized, double-blind, crossover trial in which 40 adults were exposed to TRAP for 2 h at the sidewalk of a busy road. During the exposure, the participants wore the PAPR fitted with a PM filter, a PM and volatile organic compounds (VOCs) filter, or a sham filter (no filtration, Sham mode). The participants were blinded to the type of filter in their PAPR, and experienced three exposures, once for each intervention mode in random order. We measured two lung function measures (forced expiratory volume in 1 s [FEV1] and forced vital capacity [FVC]) and an airway inflammation marker (fraction of exhaled nitric oxide [FE_NO]) before and immediately after each exposure, and further measured them at different time periods after exposure. We applied linear mixed effect models to estimate the effects of the interventions on the changes of lung function from baseline values after controlling for other covariates. Compared to baseline, exposing to TRAP decreased FEV1 and FVC, and increased FEV1/FVC and FE_NO in all three intervention modes. The mixed models showed that with the sham mode as reference, lung function and airway inflammation post exposure were significantly improved by filtering both PM and VOCs, but marginally affected by filtering only PM. In conclusion, the VOCs component of TRAP is responsible for the reduction in lung function caused by short-term exposure to TRAP. However, the result needs to be interpreted cautiously before further verified by laboratory experiment using purely isolated component(s) of TRAP.

Ambient PM2.5 exposures and systemic inflammation in women with early pregnancy

The association between ambient fine particulate matter (PM_2.5) and systemic inflammation in women with early pregnancy is unclear. This study estimated the effects of PM_2.5 exposures on inflammatory biomarkers in women with normal early pregnancy (NEP) or clinically recognized early pregnancy loss (CREPL). Serum interleukin-1beta (IL-1β), interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-α) were measured in 228 early pregnant women recruited in Tianjin, China. Maternal PM_2.5 exposures at lag 0 through lag 30 before blood collection were estimated using temporally-adjusted land use regression models. Daily exposures to ambient PM₁₀, NO₂, SO₂, CO and 8-hours maximum ozone were estimated using city-level concentrations. Single-day lag effects at lag 0 through lag 7 were estimated using multivariable linear regression models. Distributed lag effects and cumulative effects over the preceding seven days and 30 days were estimated using distributed lag non-linear models. Serum IL-1β (8.0% increase at lag 3), IL-6 (33.9% increase at lag 5) and TNF-α (12.7% increase at lag 5) in early pregnant women were significantly increased with an interquartile range increase in PM_2.5 exposures adjusted for temporal confounders and demographic characteristics. These effects were robust in several two-pollutant models. Distributed lag effects over the preceding 30 days also showed that the three cytokines were significantly increased with PM_2.5 on some lag days. Among all cumulative effects of PM_2.5 on the three cytokines in all subjects or in the two groups, only IL-6 was significantly increased in CREPL women over the preceding seven days and 30 days. No significant cumulative effect of PM_2.5 was observed in NEP women. In conclusion, exposure to ambient PM_2.5 may induce systemic inflammation in women in the first trimester of pregnancy. Whether the PM_2.5-related cumulative increase in maternal IL-6 is involved in the pathogenic mechanisms of early pregnancy loss needs to be identified in future research.

A unified empirical modeling approach for particulate matter and NO2 in a coastal city in China

Modeling air pollutants on a fine spatiotemporal scale is necessary for health studies that focus on critical short-term exposure windows. A unified empirical modeling approach is useful for health studies; however, it is unclear whether this approach can be used in a coastal city for air pollutants driven by local emissions and regional meteorological factors. An advanced empirical modeling approach was used to develop exposure models from October 2012 to December 2019, for particulate matter with aerodynamic diameters less than or equal to 2.5 and 10 μm (PM_2.5 and PM₁₀) and nitrogen dioxide (NO₂) in the coastal city of Shanghai, China. Air pollutant concentrations were obtained from daily measurements at 55 administrative monitoring sites that were integrated into three-day average concentrations. Data on a large array of geographic variables were collected, and their dimensions were reduced using the partial least squares regression method. A geostatistical model using the land-use regression approach in a universal kriging framework was developed to estimate short-term exposure concentrations. The prediction ability of the models were determined by leave-one (site)-out cross-validation (LOOCV) and external validation (EV). Compared to the LOOCV results, the EV results for PM_2.5 and PM₁₀ were consistently reliable, but the EV for NO₂ had a larger root mean squared error. The temporal random effects involved in the model structure were interpreted using sensitivity analyses. This affected the short-term PM_2.5 and PM₁₀ model predictions. This unified empirical modeling approach was successfully used for particulate matter in Shanghai, where air pollution is affected by complex regional and meteorological conditions. These exposure models are going to be applied for making exposure predictions at residential locations for short-term exposure predictions in the "Growth trajectories and air pollution" (GAAP) study in Shanghai that focuses on maternal and early life exposure to air pollutants.

Modeling spatial variation of gaseous air pollutants and particulate matters in a Metropolitan area using mobile monitoring data

Geo-statistical models have been applied to assess fine-scale air pollution exposures in epidemiological studies. Many of the models were developed for criteria air pollutants rather than others that have not been regulated (e.g., ultrafine particles, black carbon, and benzene) which may also be harmful to human health. We aim to develop spatial models for regulated and non-regulated air pollutants using 6 algorithms and compare their prediction performances. A mobile platform with fast-response monitors was used to measure gaseous air pollutants (nitrogen dioxides, carbon monoxide, sulfur dioxides, ozone, benzene, toluene, methanol) and particulate matters (black carbon, surface area, count- and volume-concentrations of ultrafine particles) in Beijing, China for 30 days from July to October 2008. Mobile monitoring data for model building were spatially aggregated into 130 road segments of approximately 600-m interval on the sampling routes after temporal adjustment of background concentrations. The best models for the air pollutants were dominated by traffic variables, which explained more than 60% of the spatial variations (range: 0.61 for methanol to 0.88 for ozone) based on the highest cross-validation R² and the lowest root mean square error among different algorithms. Amongst the 6 algorithms, the spatial models using partial least squares regression (PLS, a dimension reduction algorithm) and random forest (RF, a machine learning algorithm) algorithms outperformed the models with other algorithms. Exposure predictions from the best models varied substantially with distinct spatial patterns between the air pollutants. Predictions with multiple modeling algorithms were moderately correlated with each other for the same pollutant at the fine-scale grids across the city. Exposure models, especially based on PLS and RF algorithms, captured the spatial variation of short-term average concentrations, had adequate predictive validity, and could be applied to assess toxic air pollutant exposures in human health studies.

Probing ^{93m}Mo Isomer Depletion with an Isomer Beam

The isomer depletion of ^{93m}Mo was recently reported [Chiara et al., Nature (London) 554, 216 (2018)NATUAS0028-083610.1038/nature25483] as the first direct observation of nuclear excitation by electron capture (NEEC). However, the measured excitation probability of 1.0(3)% is far beyond the theoretical expectation. In order to understand the inconsistency between theory and experiment, we produce the ^{93m}Mo nuclei using the ^{12}C(^{86}Kr,5n) reaction at a beam energy of 559 MeV and transport the reaction residues to a detection station far away from the target area employing a secondary beam line. The isomer depletion is expected to occur during the slowdown process of the ions in the stopping material. In such a low γ-ray background environment, the signature of isomer depletion is not observed, and an upper limit of 2×10^{-5} is estimated for the excitation probability. This is consistent with the theoretical expectation. Our findings shed doubt on the previously reported NEEC phenomenon and highlight the necessity and feasibility of further experimental investigations for reexamining the isomer depletion under low γ-ray background.

Associations of Exposure to Fine Particulate Matter Mass and Constituents with Systemic Inflammation: A Cross-Sectional Study of Urban Older Adults in China

Systemic inflammation is a key mechanism in the development of cardiovascular diseases induced by exposure to fine particles (particles with aerodynamic diameter ≤2.5 μm [PM_2.5]). However, little is known about the effects of chemical constituents of PM_2.5 on systemic inflammation. In this cross-sectional study, filter samples of personal exposure to PM_2.5 were collected from community-dwelling older adults in Tianjin, China, and the chemical constituents of PM_2.5 were analyzed. Blood samples were collected immediately after the PM_2.5 sample collection. Seventeen cytokines were measured as targets. A linear regression model was applied to estimate the relative effects of PM_2.5 and its chemical constituents on the measured cytokines. A positive matrix factorization model was employed to distinguish the sources of PM_2.5. The calculated source contributions were used to estimate their effects on cytokines. After adjusting for other covariates, higher PM_2.5-bound copper was significantly associated with increased levels of interleukin (IL)1β, IL6, IL10, and IL17 levels. Source analysis showed that an increase in PM_2.5 concentration that originated from tire/brake wear and cooking emissions was significantly associated with enhanced levels of IL1β, IL6, tumor necrosis factor alpha (TNFα), and IL17. In summary, personal exposure to some PM_2.5 constituents and specific sources could increase systemic inflammation in older adults. These findings may explain the cardiopulmonary effects of specific particulate chemical constituents of urban air pollution.

Circulating myeloid-derived suppressors cells correlate with clinicopathological characteristics and outcomes undergoing neoadjuvant chemoimmunotherapy in non-small cell lung cancer

PURPOSE

Myeloid-derived suppressors cells (MDSCs) are heterogeneous immunosuppressive cells, closely related to the development, efficacy and prognosis in various tumors. The relationship between clinicopathological characteristics, efficacy of neoadjuvant chemoimmunotherapy (NCIO) and circulating MDSCs in patients with non-small cell lung cancer (NSCLC) was investigated in this study.

METHODS

This study analyzed the clinical data of patients diagnosed at Department of Thoracic Surgery, Beijing Chest Hospital from November 2020 to August 2021. MDSCs and T cells subgroups were measured in fresh peripheral blood mononuclear cells(PBMCs) at baseline. Flow cytometry was used to detect MDSCs and T cells subgroups.

RESULTS

A total of 78 patients with NSCLC and 20 patients with benign nodule underwent direct surgery. 23 patients with NSCLC scheduled to accept NCIO before surgery. NSCLC had elevated levels of total MDSCs, PMN-MDSCs and M-MDSCs compared to patients with benign nodule. MDSCs subgroups were correlated to the pTNM stage in NSCLC patients. The frequency of total MDSCs were moderately positively correlated with regulatory T cells (Tregs)(r = 0.3597, P < 0.01) and negatively correlated with CD4 + T cells(r = 0.2714, P < 0.05). The baseline levels of total MDSCs, PMN-MDSCs and Tregs in pCR patients were significantly decreased than those of non-pCR patients (P < 0.05).

CONCLUSION

Circulating MDSCs were increased in NSCLC patients. MDSC subgroups were related to pTNM stage in NSCLC patients. Total MDSCs were positively correlated with Tregs levels and negatively correlated with CD4 + T cells in peripheral blood. The level of MDSCs and Tregs in peripheral blood may have potential value in predicting pathological response in NSCLC.

Mass Concentration, Source and Health Risk Assessment of Volatile Organic Compounds in Nine Cities of Northeast China

From April 2008 to July 2009, ambient measurements of 58 volatile organic compounds (VOCs), including alkanes, alkenes, and aromatics, were conducted in nine industrial cities (Shenyang, Fushun, Changchun, Jilin, Harbin, Daqing, Huludao, Anshan and Tianjin) of the Northeast Region, China (NRC). Daqing had the highest concentration of VOCs (519.68 ± 309.88 μg/m3), followed by Changchun (345.01 ± 170.52 μg/m3), Harbin (231.14 ± 46.69 μg/m3), Jilin (221.63 ± 34.32 μg/m3), Huludao (195.92 ± 103.26 μg/m3), Fushun (135.43 ± 46.01 μg/m3), Anshan (109.68 ± 23.27 μg/m3), Tianjin (104.31 ± 46.04 μg/m3), Shenyang (75.2 ± 40.09 μg/m3). Alkanes constituted the largest percentage (>40%) in concentrations of the quantified VOCs in NRC, and the exception was Tianjin dominated by aromatics (about 52.34%). Although alkanes were the most abundant VOCs at the cities, the most important VOCs contributing to ozone formation potential (OFP) were alkenes and aromatics. Changchun had the highest OFP (537.3 μg/m3), Tianjin had the lowest OFP (111.7 μg/m3). The main active species contributing to OFP in the nine cities were C2~C6 alkanes, C7~C8 aromatic hydrocarbons, individual cities (Daqing) contained n-hexane, propane and other alkane species. Correlation between individual hydrocarbons, B/T ratio and principal component analysis model (PCA) were deployed to explore the source contributions. The results showed that the source of vehicle exhausts was one of the primary sources of VOCs in all nine cities. Additionally, individual cities, such as Daqing, petrochemical industry was founded to be an important source of VOCs. The results gained from this study provided a large of useful information for better understanding the characteristics and sources of ambient VOCs incities of NRC. The non-carcinogenic risk values of the nine cities were within the safe range recognized by the U.S. Environmental Protection Agency (HQ < 1), and the lifetime carcinogenic risk values of benzene were 3.82 × 10−5~1.28 × 10−4, which were higher than the safety range specified by the US Environmental Protection Agency (R < 1.00 × 10−6). The results of risk values indicated that there was a risk of cancer in these cities.

Characteristics, Source Contributions, and Source-Specific Health Risks of PM2.5-Bound Polycyclic Aromatic Hydrocarbons for Senior Citizens during the Heating Season in Tianjin, China

Polycyclic aromatic hydrocarbons (PAHs) have carcinogenic impacts on human health. However, limited studies are available on the characteristics, sources, and source-specific health risks of PM2.5-bound PAHs based on personal exposure data, and comparisons of the contributions of indoor and outdoor sources are also lacking. We recruited 101 senior citizens in the winter of 2011 for personal PM2.5 sample collection. Fourteen PAHs were analyzed, potential sources were apportioned using positive matrix factorization (PMF), and inhalational carcinogenic risks of each source were estimated. Six emission sources were identified, including coal combustion, gasoline emission, diesel emission, biomass burning, cooking, and environmental tobacco smoking (ETS). The contribution to carcinogenic risk of each source occurred in the following sequence: biomass burning > diesel emission > gasoline emission > ETS > coal combustion > cooking. Moreover, the contributions of biomass burning, diesel emission, ETS, and indoor sources (sum of cooking and ETS) to PAH-induced carcinogenic risk were higher than those to the PAH mass concentration, suggesting severe carcinogenic risk per unit contribution. This study revealed the contribution of indoor and outdoor sources to mass concentration and carcinogenic risk of PM2.5-bound PAHs, which could act as a guide to mitigate the exposure level and risk of PM2.5-bound PAHs.

Maternal exposure to ambient PM2.5 and term birth weight: A systematic review and meta-analysis of effect estimates

Effect estimates of prenatal exposure to ambient PM_2.5 on change in grams (β) of birth weight among term births (≥37 weeks of gestation; term birth weight, TBW) vary widely across studies. We present the first systematic review and meta-analysis of evidence regarding these associations. Sixty-two studies met the eligibility criteria for this review, and 31 studies were included in the meta-analysis. Random-effects meta-analysis was used to assess the quantitative relationships. Subgroup analyses were performed to gain insight into heterogeneity derived from exposure assessment methods (grouped by land use regression [LUR]-models, aerosol optical depth [AOD]-based models, interpolation/dispersion/Bayesian models, and data from monitoring stations), study regions, and concentrations of PM_2.5 exposure. The overall pooled estimate involving 23,925,941 newborns showed that TBW was negatively associated with PM_2.5 exposure (per 10 μg/m³ increment) during the entire pregnancy (β = -16.54 g), but with high heterogeneity (I² = 95.6%). The effect estimate in the LUR-models subgroup (β = -16.77 g) was the closest to the overall estimate and with less heterogeneity (I² = 18.3%) than in the other subgroups of AOD-based models (β = -41.58 g; I² = 95.6%), interpolation/dispersion models (β = -10.78 g; I² = 86.6%), and data from monitoring stations (β = -11.53 g; I² = 97.3%). Even PM_2.5 exposure levels of lower than 10 μg/m³ (the WHO air quality guideline value) had adverse effects on TBW. The LUR-models subgroup was the only subgroup that obtained similar significant of negative associations during the three trimesters as the overall trimester-specific analyses. In conclusion, TBW was negatively associated with maternal PM_2.5 exposures during the entire pregnancy and each trimester. More studies based on relatively standardized exposure assessment methods need to be conducted to further understand the precise susceptible exposure time windows and potential mechanisms.

Inexpensive Anti-Icing Concrete Material for Application to Tunnel and Slope Engineering Infrastructures in Cold Regions

The formation of ice hangings on the surfaces of concrete tunnel linings and sloped rock masses in cold regions endangers railroad and highway traffic. However, an inexpensive anti-icing material that meets both performance and cost requirements has not yet been developed for application in tunnel and slope engineering infrastructures in cold regions. Most current advanced anti-icing materials are expensive, and fabrication and spraying are both cumbersome, which limits their widespread application to tunnel and slope engineering. Because concrete is a widely used construction material owing to its excellent mechanical properties and low cost, we developed an inexpensive, environmentally friendly anti-icing concrete material (AICM). The AICM can be easily fabricated and sprayed onto the surfaces of large-area concrete or rock substrates and exhibits excellent superhydrophobicity (CA: 151°, SA: 6.7°), surface robustness, water resistance, chemical durability, good anti-icing, easy deicing (deicing stress: 0.06 MPa), and excellent long-term durability in freeze-thaw cycles in low-temperature environments. In addition, a novel fractal theory-based model of ice adhesion shear stress was developed and revealed the mechanism through which an AICM with a composite micro/nanostructure easily deices. The AICM has good application prospects and serves as an important guide for mitigating the formation of ice hangings in tunnel and slope engineering infrastructures in cold regions.

Acute cardiovascular effects of traffic-related air pollution (TRAP) exposure in healthy adults: A randomized, blinded, crossover intervention study

Exposure to traffic-related air pollution (TRAP) may enhance the risk of cardiovascular disease. However, the short-term effects of TRAP components on the cardiovascular system are not well understood. We conducted a randomized, double-blinded, crossover intervention study in which 39 healthy university students spent 2 h next to a busy road. Participants wore a powered air-purifying respirator (PAPR) or an N95 mask. PAPRs were equipped with a filter for particulate matter (PM), a PM and volatile organic compounds (VOCs) filter or a sham filter. Participants were blinded to PAPR filter type and underwent randomized exposures four times, once for each intervention mode. Blood pressure (BP), heart rate (HR) and heart rate variability (HRV) were measured before, during and for 6 h after the roadside exposure. Linear mixed-effect models were used to evaluate the effects of the interventions relative to baseline controlling for other covariates. All HRV measures increased during and following exposure for all intervention modes. Some HRV measures (SDNN and rMSSD during exposure and SDNN after exposure) were marginally affected by PM filtration. Wearing the N95 mask affected VLF power and rMSSD responses to traffic exposure differently than the PAPR interventions. Both systolic and diastolic BP increased slightly during exposure, but then were generally lower than baseline after exposure for the sham and filter interventions. HR, which fell during exposure and mostly remained lower than baseline after exposure, was lower yet with all filter interventions compared to the sham mode following exposure. Therefore, short-term exposure to traffic acutely affects HRV, BP and HR, but N95 mask and PAPR interventions generally show little efficacy in reducing these effects. Removing the PM component of TRAP has some limited effects on HRV responses to exposure but exaggerates the traffic-related decrease in HR. HRV findings from N95 mask interventions need to be interpreted cautiously.

Maternal exposure to ambient air pollution and congenital heart defects in China

BACKGROUND

Evidence of maternal exposure to ambient air pollution on congenital heart defects (CHD) has been mixed and are still relatively limited in developing countries. We aimed to investigate the association between maternal exposure to air pollution and CHD in China.

METHOD

This longitudinal, population-based, case-control study consecutively recruited fetuses with CHD and healthy volunteers from 21 cities, Southern China, between January 2006 and December 2016. Residential address at delivery was linked to random forests models to estimate maternal exposure to particulate matter with an aerodynamic diameter of ≤ 1 µm (PM₁), ≤2.5 µm, and ≤10 µm as well as nitrogen dioxides, in three trimesters. The CHD cases were evaluated by obstetrician, pediatrician, or cardiologist, and confirmed by cardia ultrasound. The CHD subtypes were coded using the International Classification Diseases. Adjusted logistic regression models were used to assess the associations between air pollutants and CHD and its subtypes.

RESULTS

A total of 7055 isolated CHD and 6423 controls were included in the current analysis. Maternal air pollution exposures were consistently higher among cases than those among controls. Logistic regression analyses showed that maternal exposure to all air pollutants during the first trimester was associated with an increased odds of CHD (e.g., an interquartile range [13.3 µg/m³] increase in PM₁ was associated with 1.09-fold ([95% confidence interval, 1.01-1.18]) greater odds of CHD). No significant associations were observed for maternal air pollution exposures during the second trimester and the third trimester. The pattern of the associations between air pollutants and different CHD subtypes was mixed.

CONCLUSIONS

Maternal exposure to greater levels of air pollutants during the pregnancy, especially the first trimester, is associated with higher odds of CHD in offspring. Further longitudinal well-designed studies are warranted to confirm our findings.

Aircraft-based observation of gaseous pollutants in the lower troposphere over the Beijing-Tianjin-Hebei region

To investigate the spatial and vertical distribution of atmospheric pollutants (SO₂, NO_x, CO and O₃), aircraft-based measurements (model: Yun-12, 12 flights, 27 h total flight time) were conducted from near the surface up to 2400 m over the Beijing-Tianjin-Hebei (BTH) region between June 17th and July 22nd 2016. The results showed that high concentrations of primary gaseous pollutants (SO₂, NO_x, CO) were generally present in Beijing, Tianjin, Langfang and Tangshan areas, while high values of O₃ frequently appeared in areas far from the city. The flights at noon and dusk measured higher O₃ concentrations at 600 m and lower O₃ concentrations at higher altitudes, implying a strong influence by photochemical production. Back trajectory analysis suggested that the high levels of gaseous pollutants, especially at 600 m, were associated with pollution sources transported from the southerly direction during the observation period. The first simultaneous vertical distribution measurements using aircraft and tethered balloon were conducted in Gaocun (a rural site between Beijing and Tianjin) on June 17th. The results indicated that an inversion layer at the top of the planetary boundary layer (PBL) significantly suppressed vertical exchange through the PBL and resulted in a "two-layer" vertical distribution of pollutants above and below the PBL. Additionally, a residual high O₃ layer (79.9 ± 2.5 ppb, 500-1000 m) was observed above the PBL, and it contributed to the surface peak O₃ level at noon through downward transport along with the opening up of the PBL. These results indicate that coupled effects of horizontal and vertical transport should be investigated in future studies to improve the chemical transport models used to study the vertical distribution and regional transport over the BTH region.

[A nested case-control study on relationship of traditional and combined lipid metabolism indexes with incidence of diabetes]

Objective: To explore the relationship between lipid indicators and the incidence of diabetes, and to compare the diabetes prediction and identification power of traditional lipid combined lipid indicators, in order to explore the best alternative indicators for identifying and predicting diabetes. Methods: Based on the Jinchang cohort, a nested case-control study was conducted in 1 025 new cases of diabetes after excluding patients with malignant tumor and related endocrine, circulatory system disease, then an age (±2 years), gender matched 1∶1 control group of 1 025 cases was set to analyze the relationship between the incidence of diabetes and lipid parameters. Results: Among the traditional lipid parameters, the fourth quartile of TG, TC, and LDL-C indicated higher risks of developing diabetes, which was 14.00 times (95%CI: 9.73-20.15), 2.15 times (95%CI: 1.65-2.79) and 1.66 times (95%CI: 1.29-2.14) than that of the first quartile, respectively. The risk of developing diabetes indicated by the fourth quartile of HDL-C was 0.21 times than that indicated by the first quartile (95%CI: 0.15-0.28). In the combined lipid parameters, the fourth quartile of TG/HDL-C, TC/HDL-C, LDL-C/HDL-C and non-HDL-C indicated higher risks of developing diabetes, which was 14.86 times (95%CI: 10.35-21.34), 8.12 times (95%CI: 5.94-11.01), 5.85 times (95%CI:4.34-7.88) and 5.20 times (95%CI: 3.85-7.03) than that indicated by the first quartile, respectively. The areas under the ROC curve of TG, TC, HDL-C, LDL-C, TG/HDL-C, TC/HDL-C, LDL-C/HDL-C and non-HDL-C were 0.76 (95%CI: 0.74-0.78), 0.59 (95%CI: 0.57-0.61), 0.67 (95%CI: 0.65-0.69), 0.57 (95%CI: 0.55-0.59), 0.77 (95%CI: 0.75-0.78), 0.73 (95%CI: 0.71-0.75), 0.69 (95%CI: 0.67-0.71) and 0.66 (95%CI: 0.64-0.68), respectively. The optimal diabetes predicting point cuts of TG, TC, HDL-C, LDL-C, TG/HDL-C, TC/HDL-C, LDL-C/HDL-C and non-HDL-C were 1.40, 4.70, 1.28, 3.25, 1.17, 3.43, 2.46, and 3.58 mmol/L, respectively. Conclusions: Lipid metabolic disorder is a risk factor for diabetes. TG and TG/HDL-C are the good lipid metabolism indicators for the prediction of diabetic.

[Relationship of body mass index and blood pressure with diabetes: a nested case-control study]

Objective: To explore the relationship of body mass index and blood pressure with the incidence of diabetes in Jinchang cohort. Methods: We designed a nested case-control study, a total of 29 572 workers who had no history of diabetes in baseline survey in Jinchang cohort were selected as the study cohort from June 2011 to December 2013. After 2 year follow-up, 1 021 workers with first diagnosed diabetes were selected as the case group, after 1∶1 matching according to the same gender and age ±2 years among those without diabetes, circulatory system, or endocrine system diseases during the same follow-up period, 1 021 controls was selected and 2 042 subjects were finally included. We used multivariate conditional logistic regression model, additive interaction model and multiplicative interaction model to explore the relationship of body mass index and blood pressure with the incidence of diabetes. Results: After adjusting for factors such as occupation, alcohol use, family history of diabetes, hyperuricemia, hypercholesterolemia, hypertriglyceridemia, low-HDL cholesterolemia and high-LDL cholesterolemia, multivariate conditional logistic regression analysis showed that the risk of diabetes increased with body mass index and blood pressure. Hypertension and overweight/obesity had a multiplicative interaction on the incidence of diabetes. The risks of diabetes in men and women with hypertension and overweight/obese were 2.04 times (95%CI: 1.54-2.69) and 3.88 times (95%CI: 2.55-5.91) higher than those in men and women with normal body weight and blood pressure, respectively. In the combination of BMI and blood pressure, obese individuals with SBP≥160 mmHg were 4.57 times (95%CI: 2.50-8.34) more likely to have diabetes than those with normal BMI and SBP, obese individuals with DBP≥90 mmHg were 3.40 times (95%CI: 2.19-5.28) more likely to have diabetes than those with normal BMI and DBP. Conclusions: Overweight/obesity and hypertension can increase the risk of diabetes. Health education about body weight and blood pressure controls should be strengthened to reduce the risk of diabetes.

[Prospective cohort study of relationship of triglyceride, fasting blood-glucose and triglyceride glucose product index with risk of hypertension]

Objective: To investigate the relationship of triglyceride (TG), fasting blood glucose (FPG) and triglyceride glucose product index (TyG) with the incidence of hypertension, and provide basic data for the prevention and treatment of hypertension in the population. Methods: A total of 23 581 individuals who met the research criteria in Jinchang cohort were selected as the research subjects, the Cox proportional hazard model was used to analyze the relationship of TG, FPG, and TyG with the risk of hypertension. A stratified analysis was conducted by sex. Results: After adjusting for confounding factors, compared with the normal TG group, the HR(95%CI) of the elevated TG margin group and the elevated group were 1.16 (1.01-1.34) and 1.49 (1.30-1.70), respectively in the total population. Among men, they were 1.13 (1.01-1.27) and 1.17 (1.06-1.30), and among women, they were 1.05 (0.88-1.26) and 1.06 (0.88-1.28). Compared with the normal FPG group, the HR (95%CI) of the FPG-impaired group were 1.29 (1.13-1.48) in the total population, 1.26 (1.08-1.48) in men and 1.59 (1.14-2.21) in women. Taking the lowest quartile array as a reference, the HR (95%CI) of the highest quartile array of TyG was 1.73 (1.45-2.07) in the total population, 1.32 (1.14-1.53) in men and 1.87 (1.37-2.54) in women. TG, FPG had a nonlinear dose-response relationship with the risk of hypertension, while TyG had a linear correlation with the risk of hypertension. Conclusions: Higher TG, FPG, and TyG levels are independent risk factors for the incidence of hypertension. People with higher TG, FPG and TyG are at high risk for hypertension, to which close attention should be paid in the prevention and treatment of hypertension.

A hybrid approach to estimating long-term and short-term exposure levels of ozone at the national scale in China using land use regression and Bayesian maximum entropy

Because ambient ozone (O₃) has fine spatial scale variability in addition to a large scale regional distribution, accurate exposure predictions for population health studies need to also capture fine spatial scale differences in exposure. To address these needs, we developed a 3-year average land use regression (LUR) and combined LUR and Bayesian maximum entropy (BME) by incorporating a national area variability LUR model for China from 2015 to 2017 along with data that take into account incompleteness of O₃ monitoring data into a BME framework. Spatio-temporal kriging models that either included or did not include "soft" data were used for comparison. The final LUR model included five predictor variables: road length within a 1000 m buffer, temperature, wind speed, industrial land area within a 3000 m buffer and altitude. The 1-year predicted O₃ concentrations based on the ratio method moderately agreed with the measured concentration, and the regression R² values were 0.53, 0.57 and 0.59 in the year of 2015, 2016 and 2017, respectively. The LUR/BME model performed better (R² = 0.80, root mean squared error [RMSE] = 23.5 μg/m³) than the ordinary spatio-temporal kriging model that either included "soft" data (R² = 0.57, RMSE = 49.2 μg/m³) or did not include the "soft" data (R² = 0.52, RMSE = 58.5 μg/m³). We have demonstrated that a hybrid LUR/BME model can provide accurate predictions of O₃ concentrations with high spatio-temporal resolution at the national scale in mainland China.

Large Isospin Asymmetry in ^{22}Si/^{22}O Mirror Gamow-Teller Transitions Reveals the Halo Structure of ^{22}Al

β-delayed one-proton emissions of ^{22}Si, the lightest nucleus with an isospin projection T_{z}=-3, are studied with a silicon array surrounded by high-purity germanium detectors. Properties of β-decay branches and the reduced transition probabilities for the transitions to the low-lying states of ^{22}Al are determined. Compared to the mirror β decay of ^{22}O, the largest value of mirror asymmetry in low-lying states by far, with δ=209(96), is found in the transition to the first 1^{+} excited state. Shell-model calculation with isospin-nonconserving forces, including the T=1, J=2, 3 interaction related to the s_{1/2} orbit that introduces explicitly the isospin-symmetry breaking force and describes the loosely bound nature of the wave functions of the s_{1/2} orbit, can reproduce the observed data well and consistently explain the observation that a large δ value occurs for the first but not for the second 1^{+} excited state of ^{22}Al. Our results, while supporting the proton-halo structure in ^{22}Al, might provide another means to identify halo nuclei.

Ambient PM2.5 exposures and systemic biomarkers of lipid peroxidation and total antioxidant capacity in early pregnancy

Evidence for effects of PM_2.5 on systemic oxidative stress in pregnant women is limited, especially in early pregnancy. To estimate the associations between ambient PM_2.5 exposures and biomarkers of lipid peroxidation and total antioxidant capacity (T-AOC) in women with normal early pregnancy (NEP) and women with clinically recognized early pregnancy loss (CREPL), 206 early pregnant women who had measurements of serum malondialdehyde (MDA) and T-AOC were recruited from a larger case-control study in Tianjin, China from December 2017 to July 2018. Ambient PM_2.5 concentrations of eight single-day lags exposure time windows before blood collection at the women's residential addresses were estimated using temporally-adjusted land use regression models. Effects of PM_2.5 exposures on percentage change in the biomarkers were estimated using multivariable linear regression models adjusted for month, temperature, relative humidity, gestational age and other covariates. Unconstrained distributed lag models were used to estimate net cumulative effects. Increased serum MDA and T-AOC were significantly associated with increases in PM_2.5 at several lag exposure time windows in both groups. The net effects of each interquartile range increase in PM_2.5 over the preceding 8 days on MDA were significantly higher (p < 0.001) in CREPL [52% (95% CI: 41%, 62%)] than NEP [22% (95% CI: 9%, 36%)] women. Net effects of each interquartile range increase in PM_2.5 over the preceding 5 days on T-AOC were significantly lower (p = 0.010) in CREPL [14% (95% CI: 9%, 19%)] than NEP [24% (95% CI: 18%, 29%)] women. Exposure to ambient PM_2.5 may induce systemic lipid peroxidation and antioxidant response in early pregnant women. More severe lipid peroxidation and insufficient antioxidant capacity associated with PM_2.5 was found in CREPL women than NEP women. Future studies should focus on mechanisms of individual susceptibility and interventions to reduce PM_2.5-related oxidative stress in the first trimester.

Vertical distribution of volatile organic compounds conducted by tethered balloon in the Beijing-Tianjin-Hebei region of China

Volatile organic compounds (VOCs) as precursors of ozone and secondary organic aerosols can cause adverse effects on the environment and human health. However, knowledge of the VOC vertical profile in the lower troposphere of major Chinese cities is poorly understood. In this study, tethered balloon flights were conducted over the juncture of Beijing-Tianjin-Hebei in China during the winter of 2016. Thirty-six vertical air samples were collected on selected heavy and light pollution days at altitudes of 50-1000 meters above ground level. On average, the concentration of total VOCs (TVOCs) at 50-100 m was 4.9 times higher than at 900-1000 m (46.9 ppbV vs. 8.0 ppbV). TVOC concentrations changed rapidly from altitudes of 50-100 to 401-500 m, with an average decrease of 72%. With further altitude increase, the TVOC concentration gradually decreased. The xylene/benzene ratios of 34/36 air samples were lower than 1.1, and the benzene/toluene ratios of 34/36 samples were higher than 0.4, indicating the occurrence of aged air mass during the sampling period. Alkenes contributed most in terms of both OH loss rate (39%-71%) and ozone formation potential (40%-72%), followed by aromatics (6%-38%). Finally, the main factors affecting the vertical distributions of VOCs were local source emission and negative dispersion conditions on polluted days. These data could advance our scientific understanding of VOC vertical distribution.

Chemical characteristics of road dust PM2.5 fraction in oasis cities at the margin of Tarim Basin

In order to understand the compositions characteristics of particulate matter with aerodynamic diameter less than 2.5 μm (PM_2.5) fraction in road dust (RD_2.5) of oasis cities on the edge of Tarim Basin, 30 road dust (RD) samples were collected in Kashi, Cele, and Yutian in the spring, 2018, and RD_2.5 was collected using the resuspension approach. Eight water-soluble ions, 39 trace elements and 8 fractions of carbon-containing species in PM_2.5 were analyzed. Ca²⁺ and Ca were the most abundant ions and elements in RD_2.5 (7.1% and 9.5%). Cl^- in RD_2.5 was affected not only by attributed to saline-alkali soils in oasis cities of the Tarim Basin and dust from Taklimakan Desert but also by human activities. Moreover, the organic carbon/elemental carbon (OC/EC) ratio indicated that carbon components in RD_2.5 in Cele town mainly come from fossil fuel combustion, while those in Yutian and Kashi mainly come from biomass combustion. It is noteworthy that high Ca in RD_2.5 was seriously affected by anthropogenic emissions, and high Na and K contents in RD_2.5 could be derived from soil and desert dust. It was estimated that Cd, Tl, Sn and Cr were emitted from anthropogenic emissions using the enrichment factor. The coefficients of divergence (COD) result indicated that the influence of local emission on road dust emission is greater than that of long-distance transmission. This study is the first time to comprehensively analyze the chemical characteristics of road dust in oasis cities, and the results provides the sources of road dust at the margin of Tarim Basin.

Evaluation of a New Chemical Mechanism for 2-Amino-2-methyl-1-propanol in a Reactive Environment from CSIRO Smog Chamber Experiments

Amines are considered as an emerging class of atmospheric pollutants that are of great importance to atmospheric chemistry and new particle formation. As a typical amine, 2-amino-2-methyl-1-propanol (AMP) is one of the proposed solvents for capturing CO₂ from flue gas streams in amine-based post-combustion CO₂ capture plants, and it is expected to result in AMP emission and secondary product formation in the atmosphere. However, the current knowledge of its atmospheric chemistry and kinetics is poorly understood, particularly in a reactive environment. In this work, we used the CSIRO smog chamber to study the photo-oxidation of AMP in the presence of volatile organic compound (VOC)-NOx surrogate mixtures over a range of initial amine concentrations. O₃ formation was significantly inhibited when AMP was added to the surrogate VOC-NOx mixtures, implying that AMP could alter known atmospheric chemical reaction pathways and the prevailing reactivity. Simultaneously, a large amount of AMP-derived secondary aerosol was formed, with a considerably high aerosol mass yield (i.e., ratio of aerosol formed to reacted AMP) of 1.06 ± 0.20. Based on updated knowledge of its kinetics, oxidation pathways, and product yields, we have developed a new mechanism (designated as CSIAMP-19), integrated it into the Carbon Bond 6 (CB6) chemical mechanism, and evaluated it against available smog chamber data. Compared with the existing AMP mechanism (designated as CarterAMP-08), the modified CB6 with CSIAMP-19 mechanism improves prediction against AMP-VOC-NOx experiments across a range of initial AMP concentrations, within ±10% model error for gross ozone production. Our results contribute to scientific understanding of AMP photochemistry and to the development of the chemical mechanism of other amines. Once some potential limitations are considered, the updated AMP reaction scheme can be further embedded into the chemical transport model for regional modeling scenarios where AMP-related emissions are of concern.

Combined use of principal component analysis and artificial neural network approach to improve estimates of PM2.5 personal exposure: A case study on older adults

Accurate exposure estimate of the air pollutant PM_2.5 is required to evaluate its health impacts in epidemiological studies, due to its adverse effects on human's respiratory and cardiovascular systems. However, traditional personal sampling is time and cost consuming. Thus, modeling techniques are needed to accurately predict the personal exposure level to PM_2.5. In this study, a total of 117 older adults over 60 were recruited in Tianjin, a heavily polluted city in northern China, for indoor, outdoor and personal PM_2.5 sampling. Eighteen variables which may increase the exposure level of older adults were recorded for artificial neural network (ANN) simulation. Four modeling techniques, including time-integrated activity modeling, Monte Carlo simulation, ANN modeling, and combined use of principal component analysis (PCA) and ANN model, were used to evaluate their ability for predicting real exposure values of PM_2.5. The results of traditional time-weighted activity modeling showed the lowest correlation with measured values with R² of 0.57 and 0.42 in winter and summer, respectively. For Monte Carlo simulation, high correlation was obtained (R² of 0.93 and 0.92 in winter and summer, respectively) between percentiles of the predicted and the real exposure values. Compared with the simple ANN models, the combined use of PCA and ANN produced the most accurate results with R² of 0.99 and RMSE lower than 15. Since the information of the input variables for the PCA-ANN model can be obtained from the questionnaire and fixed air quality monitoring sites, this technique shows a great potential in predicting personal exposure level to the air pollutant because no additional concentration measurement is needed.

Positive-Parity Linear-Chain Molecular Band in ^{16}C

An inelastic excitation and cluster-decay experiment ^{2}H(^{16}C,^{4}He+^{12}Be or ^{6}He+^{10}Be)^{2}H was carried out to investigate the linear-chain clustering structure in neutron-rich ^{16}C. For the first time, decay paths from the ^{16}C resonances to various states of the final nuclei were determined, thanks to the well-resolved Q-value spectra obtained from the threefold coincident measurement. The close-threshold resonance at 16.5 MeV is assigned as the J^{π}=0^{+} band head of the predicted positive-parity linear-chain molecular band with (3/2_{π}^{-})^{2}(1/2_{σ}^{-})^{2} configuration, according to the associated angular correlation and decay analysis. Other members of this band were found at 17.3, 19.4, and 21.6 MeV based on their selective decay properties, being consistent with the theoretical predictions. Another intriguing high-lying state was observed at 27.2 MeV which decays almost exclusively to ^{6}He+^{10}Be(∼6  MeV) final channel, corresponding well to another predicted linear-chain structure with the pure σ-bond configuration.

Tephritidae bacterial symbionts: potentials for pest management

Tephritidae is a large family that includes several fruit and vegetable pests. These organisms usually harbor a variegated bacterial community in their digestive systems. Symbiotic associations of bacteria and fruit flies have been well-studied in the genera Anastrepha, Bactrocera, Ceratitis, and Rhagoletis. Molecular and culture-based techniques indicate that many genera of the Enterobacteriaceae family, especially the genera of Klebsiella, Enterobacter, Pectobacterium, Citrobacter, Erwinia, and Providencia constitute the most prevalent populations in the gut of fruit flies. The function of symbiotic bacteria provides a promising strategy for the biological control of insect pests. Gut bacteria can be used for controlling fruit fly through many ways, including attracting as odors, enhancing the success of sterile insect technique, declining the pesticide resistance, mass rearing of parasitoids and so on. New technology and recent research improved our knowledge of the gut bacteria diversity and function, which increased their potential for pest management. In this review, we discussed the diversity of bacteria in the economically important fruit fly and the use of these bacteria for controlling fruit fly populations. All the information is important for strengthening the future research of new strategies developed for insect pest control by the understanding of symbiotic relationships and multitrophic interactions between host plant and insects.

Biosynthesis of poly-γ-glutamic acid in Escherichia coli by heterologous expression of pgsBCAE operon from Bacillus

AIMS

Poly-γ-glutamic acid (γ-PGA) is an excellent water-soluble biosynthesis material. To confirm the rate-limiting steps of γ-PGA biosynthesis pathway, we introduced a heterologous Bacillus strain pathway and employed an enzyme-modulated dismemberment strategy in Escherichia coli.

METHODS AND RESULTS

In this study, we heterologously introduced the γ-PGA biosynthesis pathway of two laboratory-preserved strains-Bacillus amyloliquefaciens FZB42 and Bacillus subtilis 168 into E. coli, and compared their γ-PGA production levels. Next, by changing the plasmid copy numbers and supplying sodium glutamate, we explored the effects of gene expression levels and concentrations of the substrate l-glutamic acid on γ-PGA production. We finally employed a two-plasmid induction system using an enzyme-modulated dismemberment of pgsBCAE operon to confirm the rate-limiting genes of the γ-PGA biosynthesis pathway.

CONCLUSION

Through heterologously over-expressing the genes of the γ-PGA biosynthesis pathway and exploring gene expression levels, we produced 0·77 g l^-1 γ-PGA in strain RSF-EBCAE(BS). We also confirmed that the rate-limiting genes of the γ-PGA biosynthesis pathway were pgsB and pgsC.

SIGNIFICANCE AND IMPACT OF THE STUDY

This work is beneficial to increase γ-PGA production and study the mechanism of γ-PGA biosynthesis enzymes.

Emission factors, ozone and secondary organic aerosol formation potential of volatile organic compounds emitted from industrial biomass boilers

To evaluate the potential benefits of biomass use for air pollution control, this paper identified and quantified the emissions of major reactive organic compounds anticipated from biomass-fired industrial boilers. Wood pellets (WP) and straw pellets (SP) were burned to determine the volatile organic compound emission profiles for each biomass-boiler combination. More than 100 types of volatile organic compounds (VOCs) were measured from the two biomass boilers. The measured VOC species included alkanes, alkenes and acetylenes, aromatics, halocarbons and carbonyls. A single coal-fired boiler (CB) was also studied to provide a basis for comparison. Biomass boiler 1 (BB1) emitted relatively high proportions of alkanes (28.9%-38.1% by mass) and alkenes and acetylenes (23.4%-40.8%), while biomass boiler 2 (BB2) emitted relatively high proportions of aromatics (27.9%-29.2%) and oxygenated VOCs (33.0%-44.8%). The total VOC (TVOC) emission factors from BB1 (128.59-146.16 mg/kg) were higher than those from BB2 (41.26-85.29 mg/kg). The total ozone formation potential (OFP) ranged from 6.26 to 81.75 mg/m³ with an average of 33.66 mg/m³ for the two biomass boilers. The total secondary organic aerosol potential (SOAP) ranged from 61.56 to 211.67 mg/m³ with an average of 142.27 mg/m³ for the two biomass boilers. The emission factors (EFs) of TVOCs from biomass boilers in this study were similar to those for industrial coal-fired boilers with the same thermal power. These data can supplement existing VOC emission factors for biomass combustion and thus enrich the VOC emission inventory.

A seriously sand storm mixed air-polluted area in the margin of Tarim Basin: Temporal-spatial distribution and potential sources

In order to analyze the temporal-spatial distribution characteristics of PM_2.5, PM₁₀, SO₂, NO₂, CO and O₃ in five cities and the potential sources of PM₁₀ in southern Xinjiang during 2016, we collected one year officially released data for analysis. The average PM₁₀, PM_2.5, SO₂, NO₂, O₃ and CO concentrations were 289 ± 363, 99 ± 106, 17 ± 9, 29 ± 11, 65 ± 25 μg m^-3 and 1.3 ± 0.6 mg m^-3 in southern Xinjiang in 2016, respectively. The air pollutants presented distinct seasonal and spatial distribution characteristics. During sandstorm process, the particulate matters (PM) concentrations increased abruptly, with the PM₁₀ and PM_2.5 maximum concentrations exceeding 1000 and 500 μg m^-3 in each city. The backward trajectory results showed that the air masses in Akesu, Kurla, Hotan, Kashi and Atushi were mainly from the Bayingol Mongolian Autonomous Prefecture, Kyrgyzstan, Kizilesu Kirgiz Autonomous Prefecture and Taklimakan Desert (TD). In addition, TD was the main potential contributor to ambient PM₁₀ in five cities during the dust season (DS), with a weighted potential source contribution function (WPSCF) > 0.9. While the trajectories of air masses from TD, Bayingol Mongolian Autonomous Prefecture, Urumqi-Changji Area and local emission were potential sources contributing to PM_2.5 in these five cities during DS, with a WPSCF > 0.7. Moreover, the high weighted concentration weighted trajectory (WCWT) values were distributed in the Tarim basin, with PM₁₀ > 700 μg m^-3, however, the local emission and long distance transport contributed to the PM_2.5 > 160 μg m^-3 for five cities. This study comprehensively analyzes the pollution characteristics of air pollutants in five important cities in the southern margin of the Tarim Basin for the first time, and will provide an important reference basis for the prevention and control of air pollution in southern Xinjiang.

The influence of antibiotics on gut bacteria diversity associated with laboratory-reared Bactrocera dorsalis

The oriental fruit fly Bactrocera dorsalis (Hendel) is a destructive insect pest of a wide range of fruit crops. Commensal bacteria play a very important part in the development, reproduction, and fitness of their host fruit fly. Uncovering the function of gut bacteria has become a worldwide quest. Using antibiotics to remove gut bacteria is a common method to investigate gut bacteria function. In the present study, three types of antibiotics (tetracycline, ampicillin, and streptomycin), each with four different concentrations, were used to test their effect on the gut bacteria diversity of laboratory-reared B. dorsalis. Combined antibiotics can change bacteria diversity, including cultivable and uncultivable bacteria, for both male and female adult flies. Secondary bacteria became the dominant population in female and male adult flies with the decrease in normally predominant bacteria. However, in larvae, only the predominant bacteria decreased, the bacteria diversity did not change a lot, likely because of the short acting time of the antibiotics. The bacteria diversity did not differ among fruit fly treatments with antibiotics of different concentrations. This study showed the dynamic changes of gut bacterial diversity in antibiotics-treated flies, and provides a foundation for research on the function of gut bacteria of the oriental fruit fly.

Ambient PM2.5 and clinically recognized early pregnancy loss: A case-control study with spatiotemporal exposure predictions

BACKGROUND

Experimental research suggests that fine particulate matter (PM_2.5) exposure might affect embryonic development. However, only few population-based studies have investigated the impact of maternal exposure to PM_2.5 on the early pregnancy loss.

OBJECTIVES

To estimate associations between clinically recognized early pregnancy loss (CREPL) and exposure to ambient PM_2.5 at individual residences during peri-conception periods, with the aim to identify susceptible exposure time windows.

METHODS

CREPL cases and normal early pregnancy controls (of similar age and gravidity presenting within one week, a total of 364 pairs) were recruited between July 2017 and July 2018 among women residing in Tianjin, China. Average ambient PM_2.5 concentrations of ten exposure windows (4 weeks, 2 weeks and 1 week before conception; the first, second, third and fourth single week, the first and second 2-week periods, and the entire 4-week period after conception) at the women's residential addresses were estimated using temporally-adjusted land use regression models. Associations between PM_2.5 exposures at specific peri-conception time windows and CREPL were examined using conditional logistic regression models, adjusted for covariates.

RESULTS

Based on adjusted models, CREPL was significantly associated with a 10 μg/m³ increase in PM_2.5 exposure during the second week after conception (OR = 1.15; 95% CI: 1.04, 1.27; p = 0.005), independent of effects at other time windows. There was also an association of CREPL with PM_2.5 during the entire 4-week period after conception (OR = 1.22; 95% CI: 1.02, 1.46; p = 0.027). There was little evidence for associations with exposure during pre-conception exposure windows.

CONCLUSIONS

Maternal exposures to ambient PM_2.5 during a critical time window following conception are associated with CREPL, with the second week after conception possibly being the exposure window of most vulnerability. Future studies should focus on replicating these findings and on pathogenic mechanisms.

Water-Soluble Brown Carbon in Atmospheric Aerosols from Godavari (Nepal), a Regional Representative of South Asia

Brown carbon (BrC) has recently emerged as an important light-absorbing aerosol. This study provides interannual and seasonal variations in light absorption properties, chemical composition, and sources of water-soluble BrC (WS-BrC) based on PM₁₀ samples collected in Godavari, Nepal, from April 2012 to May 2014. The mass absorption efficiency of WS-BrC at 365 nm (MAE₃₆₅) shows a clear seasonal variability, with the highest MAE₃₆₅ of 1.05 ± 0.21 m² g^-1 in premonsoon season and the lowest in monsoon season (0.59 ± 0.16 m² g^-1). The higher MAE₃₆₅ values in nonmonsoon seasons are associated with fresh biomass burning emissions. This is further substantiated by a strong correlation ( r = 0.79, P < 0.01) between Abs₃₆₅ (light absorption coefficient at 365 nm) and levoglucosan. We found, using fluorescence techniques, that humic-like and protein-like substances are the main chromophores in WS-BrC and responsible for 80.2 ± 4.1% and 19.8 ± 4.1% of the total fluorescence intensity, respectively. BrC contributes to 8.78 ± 3.74% of total light absorption over the 300-700 nm wavelength range. Considering the dominant contribution of biomass burning to BrC over Godavari, this study suggests that reduction in biomass burning emission may be a practical method for climate change mitigation in South Asia.

Inhalation cancer risk estimation of source-specific personal exposure for particulate matter-bound polycyclic aromatic hydrocarbons based on positive matrix factorization

In previous studies, inhalation cancer risk was estimated using conventional risk assessment method, which was normally based on compound-specific analysis, and cannot provide substantial data for source-specific particulate matter concentrations and pollution control. In the present study, we applied an integrated risk analysis method, which was a synthetic combination of source apportionment receptor model and risk assessment method, to estimate cancer risks associated to individual PAHs coming from specific sources. Personal exposure particulate matter samples referring to an elderly panel were collected in a community of Tianjin, Northern China, in 2009, and 12 PAH compounds were measured using GC-MS. Positive matrix factorization (PMF) was used to extract the potential sources and quantify the source contributions to the PAH mixture. Then, the lung cancer risk of each modeled source was estimated by summing up the cancer risks of all measured PAH species according to the extracted source profile. The final results indicated that the overall cancer risk was 1.12 × 10^-5, with the largest contribution from gasoline vehicle emission (44.1%). Unlike other risk estimation studies, this study was successful in combining risk analysis and source apportionment approaches, which allow estimating the potential risk of all source types and provided suitable information to select prior control strategies and mitigate the main air pollution sources that contributing to health risks.

Estimating short-term mortality and economic benefit attributable to PM10 exposure in China based on BenMAP

With the rapidly booming economy, China has been suffering from serious particulate matter (PM) pollution in recent years. In order to improve the air quality, Chinese government issued a new China National Ambient Air Quality Standard (No. GB3095-2012) in 2012. In this study, PM₁₀ exposure level was simulated based on the data of 912 newly constructed monitoring sites and Voronoi Neighborhood Averaging (VNA) interpolation method. It is widely accepted that PM₁₀ can cause short-term health effects. We calculated the short-term health benefit due to decreasing PM₁₀ concentration to the levels of China National Ambient Air Quality Standard based on Environmental Benefits Mapping and Analysis Program (BenMAP). Our results indicated that if the daily average concentration of PM₁₀ reduced to the daily Grade II standard (150 μg/m³), the avoided deaths for all cause, cardiovascular disease, and respiratory disease would be 82,000 (95%CI: 49,000-120,000), 56,000 (95%CI: 34,000-78,000), and 16,000 (95%CI: 10,000-22,000) in 2014, respectively. The economic benefits of avoiding deaths due to all cause for rolling back the concentration of PM₁₀ to the level of 50 μg/m³ were estimated to be 240 billion CNY and 16 billion CNY using willingness to pay (WTP) and human capital (HC) methods, respectively, which accounted for 0.38% (95%CI: 0.11-0.64%) and 0.03% (95%CI: 0.02-0.03%) of the total annual gross domestic product (GDP) of China in 2014.