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| 2. |
- Zhang, Yuanyuan, et al.
(författare)
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Early-life exposure to PM2.5 constituents and childhood asthma and wheezing : Findings from China, Children, Homes, Health study
- 2022
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Ingår i: Environment International. - : Elsevier. - 0160-4120 .- 1873-6750. ; 165
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Tidskriftsartikel (refereegranskat)abstract
- Background: Emerging evidence suggests that early-life (in-utero and first-year since birth) exposure to ambient PM2.5 is a risk factor for asthma onset and exacerbation among children, while the hazards caused by PM2.5 compositions remain largely unknown.Objective: To examine potential associations of early-life exposures to PM2.5 mass and its major chemical constituents with childhood asthma and wheezing.Methods: By conducting the Phase II of the China, Children, Homes, Health study, we investigated 30,325 preschool children aged 3-6 years during 2019-2020 in mainland China. Early-life exposure to PM2.5 mass and its constituents (i.e., black carbon [BC], organic matter [OM], nitrate, ammonium, sulfate) were calculated based on monthly estimates at a 1 km x 1 km resolution from satellite-based models. We adopted a novel quantile-based g-computation approach to assess the effect of a mixture of PM2.5 constituents on childhood asthma/wheezing.Results: The average PM2.5 concentrations during in-utero and the first year since birth were 64.7 +/- 10.6 and 61.8 +/- 10.5 mu g/m(3), respectively. Early-life exposures to a mixture of major PM2 center dot 5 constituents were significantly associated with increased risks of asthma and wheezing, while no evident compositions-wheezing associations were found in the first year. Each quintile increases in all five PM2.5 components exposures in utero was accordingly associated with an odds ratio of 1.18 [95% confidence interval: 1.07-1.29] for asthma and 1.08 [1.01-1.16] for wheezing. BC, OM and SO42- contributed more to risks of asthma and wheezing than the other PM2.5 constituents during early life, wherein the effects of BC were only observed during pregnancy. Sex subgroup analyses suggested stronger associations among girls of first-year exposures to PM2.5 components with childhood asthma.Conclusion: Early-life exposures to ambient PM2.5, particularly compositions of BC, OM and SO42-, are associated with an increased risk of childhood asthma.
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| 3. |
- Tang, Hu, et al.
(författare)
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Boron-Rich Molybdenum Boride with Unusual Short-Range Vacancy Ordering, Anisotropic Hardness, and Superconductivity
- 2020
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Ingår i: Chemistry of Materials. - : AMER CHEMICAL SOC. - 0897-4756 .- 1520-5002. ; 32:1, s. 459-467
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Tidskriftsartikel (refereegranskat)abstract
- Determination of the structures of materials involving more light elements such as boron-rich compounds is challenging and technically important in understanding their varied compositions and superior functionalities. Here we resolve the long-standing uncertainties in structure and composition about the highest boride (termed MoB4, Mo1-xB3, or MoB3) through the rapid formation of large sized boron-rich molybdenum boride under pressure. Using high-quality single-crystal X-ray diffraction analysis and aberration-corrected scanning transmission electron microscopy, we reveal that boron-rich molybdenum boride with a composition of Mo0.757B3 exhibits P6(3)/mmc symmetry with a partial occupancy of 0.514 in 211 Mo sites (Mol), and direct observations reveal the short-range ordering of cation vacancies in (010) crystal planes. Large anisotropic Young's moduli and Vickers hardness are seen for Mo0.757B3, which may be attributed by its two-dimensional boron distributions. Mo0.757B3 is also found to be superconducting with a transition temperature (T-c) of 2.4 K, which was confirmed by measurements of resistivity and magnetic susceptibility. Theoretical calculations suggest that the partial occupancy of Mo atoms plays a crucial role in the emergence of superconductivity.
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| 4. |
- Yu, Wei, et al.
(författare)
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Increased risk of respiratory and allergic diseases in preschoolers from building envelope dampness exposure : Repeated cross-sectional surveys in multicity China
- 2023
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Ingår i: Building and Environment. - : Elsevier. - 0360-1323 .- 1873-684X. ; 241
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Tidskriftsartikel (refereegranskat)abstract
- Building envelope dampness exposure is correlated with children's respiratory and allergic diseases. However, little research has compared the variation in the health impact of dampness exposure across multiple cities from a longitudinal perspective. A cross-sectional survey and a repeated one were conducted in children's residences in six cities: Chongqing, Shanghai, Nanjing, Wuhan, Changsha and Taiyuan, China, in 2010 (Phase I) and 2019 (Phase II). We selected 17,810 preschoolers during Phase I and 26,001 preschoolers during Phase II aged 3-6 years without changing residence since birth in the study. The proportion of residences with building envelope dampness exposure and the prevalence of respiratory and allergic diseases, except allergic rhinitis, in preschoolers significantly declined from Phase I to Phase II. Dampness exposure increased the risk for most childhood respiratory diseases in Phase II, with a 34% greater risk of lifetime-ever asthma in early residences and a 36% greater risk of current eczema in current residences. Most diseases showed a significantly positive exposureresponse relationship to the cumulative period of building envelope dampness exposure (p < 0.05). The risk of developing current eczema was approximately 1.35 and 1.73 times higher in children exposed to both early and current dampness in Phase I and Phase II, respectively, than in children who had never been exposed. These findings provide new insights into the respiratory and allergic diseases in Chinese preschoolers because of building envelope dampness exposure over the last decade. The increased risk in Phase II raises concerns about the household's dampness environment.
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| 5. |
- Li, Yachen, et al.
(författare)
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Intrauterine and early postnatal exposures to submicron particulate matter and childhood allergic rhinitis : A multicity cross-sectional study in China
- 2024
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Ingår i: Environmental Research. - : Elsevier. - 0013-9351 .- 1096-0953. ; 247
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Tidskriftsartikel (refereegranskat)abstract
- Background: Airborne particulate matter pollution has been linked to occurrence of childhood allergic rhinitis (AR). However, the relationships between exposure to particulate matter with an aerodynamic diameter <= 1 µm (PM1) during early life (in utero and first year of life) and the onset of childhood AR remain largely unknown. This study aims to investigate potential associations of in utero and first-year exposures to size-segregated PMs, including PM1, PM1-2.5, PM2.5, PM2.5-10, and PM10, with childhood AR.Methods: We investigated 29286 preschool children aged 3-6 years in 7 Chinese major cities during 2019-2020 as the Phase II of the China Children, Families, Health Study. Machine learning-based space-time models were utilized to estimate early-life residential exposure to PM1, PM2.5, and PM10 at 1 x 1-km resolutions. The concentrations of PM1-2.5 and PM2.5-10 were calculated by subtracting PM1 from PM2.5 and PM2.5 from PM10, respectively. Multiple mixed-effects logistic models were used to assess the odds ratios (ORs) and 95% confidence intervals (CIs) of childhood AR associated with per 10-µg/m3 increase in exposure to particulate air pollution during in utero period and the first year of life.Results: Among the 29286 children surveyed (mean +/- standard deviation, 4.9 +/- 0.9 years), 3652 (12.5%) were reported to be diagnosed with AR. Average PM1 concentrations during in utero period and the first year since birth were 36.3 +/- 8.6 µg/m3 and 33.1 +/- 6.9 µg/m3, respectively. Exposure to PM1 and PM2.5 during pregnancy and the first year of life was associated with an increased risk of AR in children, and the OR estimates were higher for each 10-µg/m3 increase in PM1 than for PM2.5 (e.g., 1.132 [95% CI: 1.022-1.254] vs. 1.079 [95% CI: 1.014-1.149] in pregnancy; 1.151 [95% CI: 1.014-1.306] vs. 1.095 [95% CI: 1.008-1.189] in the first year of life). No associations were observed between AR and both pre- and post-natal exposure to PM1-2.5, indicating that PM1 rather than PM1-2.5 contributed to the association between PM2.5 and childhood AR. In trimester-stratified analysis, childhood AR was only found to be associated with exposure to PM1 (OR = 1.077, 95% CI: 1.027-1.128), PM2.5 (OR = 1.048, 95% CI: 1.018-1.078), and PM10 (OR = 1.032, 95% CI: 1.007-1.058) during the third trimester of pregnancy. Subgroup analysis suggested stronger PM-AR associations among younger (<5 years old) and winter-born children.Conclusions: Prenatal and postnatal exposures to ambient PM1 and PM2.5 were associated with an increased risk of childhood AR, and PM2.5-related hazards could be predominantly attributed to PM1. These findings highlighted public health significance of formulating air quality guideline for ambient PM1 in mitigating children's AR burden caused by particulate air pollution.
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| 6. |
- Wu, Chuansha, et al.
(författare)
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Associations of Early-Life Exposure to Submicron Particulate Matter With Childhood Asthma and Wheeze in China
- 2022
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Ingår i: JAMA Network Open. - : American Medical Association (AMA). - 2574-3805. ; 5:10
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Tidskriftsartikel (refereegranskat)abstract
- IMPORTANCE Exposure to particulate matter (PM) has been associated with childhood asthma and wheeze. However, the specific associations between asthma and PM with an aerodynamic equivalent diameter of 1 mu m or less (ie, PM1), which is a contributor to PM2.5 and potentially more toxic than PM2.5, remain unclear. OBJECTIVE To investigate the association of early-life (prenatal and first year) exposure to size-segregated PM, including PM1, PM1-2.5, PM2.5, PM2.5-10, and PM10, with childhood asthma and wheeze. DESIGN, SETTING, AND PARTICIPANTS This cross-sectional study was based on a questionnaire administered between June 2019 and June 2020 to caregivers of children aged 3 to 6 years in 7 Chinese cities (Wuhan, Changsha, Taiyuan, Nanjing, Shanghai, Chongqing, and Urumqi) as the second phase of the China, Children, Homes, Health study. EXPOSURES Exposure to PM1, PM1-2.5, PM2.5, PM2.5-10, and PM10 during the prenatal period and first year of life. MAIN OUTCOMES AND MEASURES The main outcomes were caregiver-reported childhood asthma and wheeze. A machine learning-based space-time model was applied to estimate early-life PM1, PM2.5, and PM10 exposure at 1 x 1-km resolution. Concentrations of PM1-2.5 and PM2.5-10 were calculated by subtracting PM1 from PM2.5 and PM2.5 from PM10, respectively. Multilevel (city and child) logistic regression models were applied to assess associations. RESULTS Of 29 418 children whose caregivers completed the survey (15 320 boys [52.1%]; mean [SD] age, 4.9 [0.9] years), 2524 (8.6%) ever had wheeze and 1161 (3.9%) were diagnosed with asthma. Among all children, 18 514 (62.9%) were breastfed for more than 6 months and 787 (2.7%) had parental history of atopy. A total of 22 250 children (75.6%) had a mother with an educational level of university or above. Of the 25 422 children for whom information about cigarette smoking exposure was collected, 576 (2.3%) had a mother who was a current or former smoker during pregnancy and 7525 (29.7%) had passive household cigarette smoke exposure in early life. Early-life PM1, PM2.5, and PM10 exposure were significantly associated with increased risk of childhood asthma, with higher estimates per 10-mu g/m(3) increase in PM1 (OR, 1.55; 95% CI, 1.27-1.89) than in PM2.5 (OR, 1.14; 95% CI, 1.03-1.26) and PM10 (OR, 1.11; 95% CI, 1.02-1.20). No association was observed between asthma and PM1-2.5 exposure, suggesting that PM1 rather than PM1-2.5 contributed to the association between PM2.5 and childhood asthma. There were significant associations between childhood wheeze and early-life PM1 exposure (OR, 1.23; 95% CI, 1.07-1.41) and PM2.5 exposure (OR, 1.08; 95% CI, 1.01-1.16) per 10-mu g/m(3) increase in PM1 and PM2.5, respectively. CONCLUSIONS AND RELEVANCE In this cross-sectional study, higher estimates were observed for the association between PM with smaller particles, such as PM1, vs PM with larger particles and childhood asthma. The results suggest that the association between PM2.5 and childhood asthma was mainly attributable to PM1.
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| 7. |
- Wu, Chuansha, et al.
(författare)
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Modification of Food Allergy on the Associations between Early Life Exposure to Size-Specific Particulate Matter and Childhood Allergic Rhinitis
- 2024
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Ingår i: Environmental Science and Technology. - : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 58:4, s. 1813-1822
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Tidskriftsartikel (refereegranskat)abstract
- Previous studies have reported the association between particulate matter (PM) and childhood allergic rhinitis (AR). However, it is unclear whether food allergy (FA) modifies the PM-AR association. We aimed at evaluating the effect of the modification of FA on PM-AR association in preschool children. We adopted a cross-sectional study and conducted a questionnaire survey among preschool children aged 3-6 years in 7 cities in China from June 2019 to June 2020 to collect information on AR and FA. We used a combination of multilevel logistic regression and restricted cubic spline functions to quantitatively assess whether FA modifies the associations between size-specific PM exposure (1 x 1 km) and the risk of AR. The adjusted odds ratios (ORs) for AR among the children with FA as per a 10 mu g/m(3) increase in early life PM1, PM2.5, and PM10 were significantly higher than the corresponding ORs among the children without FA [e.g., OR: 1.58, 95% CI: (1.32, 1.90) vs 1.29, 95% CI: (1.18, 1.41), per 10 mu g/m(3) increase in PM1]. The interactions between FA and size-specific PM exposure and their effects on AR were statistically significant (all p-int < 0.001). FA, as an important part of the allergic disease progression, may modify the PM-AR association in preschool children.
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| 8. |
- Xu, Guobao, et al.
(författare)
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Tree ring O-18's indication of a shift to a wetter climate since the 1880s in the western Tianshan Mountains of northwestern China
- 2015
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Ingår i: Journal of Geophysical Research - Atmospheres. - 2169-897X .- 2169-8996. ; 120:13, s. 6409-6425
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Tidskriftsartikel (refereegranskat)abstract
- Central Asian droughts have drastically and significantly affected agriculture and water resource management in these arid and semiarid areas. Based on tree ring O-18 from native, dominant Schrenk spruce (Picea schrenkiana Fisch. et Mey.), we developed a 300year (1710-2010) standard precipitation-evaporation index (SPEI) reconstruction from January to August for China's western Tianshan Mountains. The regression model explained 37.6% of the variation in the SPEI reconstruction during the calibration period from 1950 to 2010. Comparison with previous drought reconstructions confirmed the robustness of our reconstruction. The 20th century has been a relatively wet period during the past 300years. The SPEI showed quasi 2, 5, and 10year cycles. Several pluvials and droughts with covariability over large areas were revealed clearly in the reconstruction. The two longest pluvials (lasting for 12years), separated by 50years, appeared in the 1900s and the 1960s. The most severe drought occurred from 1739 to 1761 and from 1886 to 1911 was the wettest period since 1710. Compared to previous investigations of hydroclimatic changes in the western Tianshan Mountains, our reconstruction revealed more low-frequency variability and indicated that climate in the western Tianshan Mountains shifted from dry to wet in 1886. This regime shift was generally consistent with other moisture reconstructions for the northeastern Tibetan Plateau and northern Pakistan and may have resulted from a strengthened westerly circulation. The opposite hydrological trends in the western Tianshan Mountains and southeastern Tibetan Plateau reveal a substantial influence of strengthened westerlies and weakening of the Indian summer monsoon.
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| 9. |
- Zhang, Yinping, et al.
(författare)
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Ten cities cross-sectional questionnaire survey of children asthma and other allergies in China
- 2013
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Ingår i: Chinese Science Bulletin. - : Springer Science and Business Media LLC. - 1001-6538 .- 1861-9541. ; 58:34, s. 4182-4189
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Tidskriftsartikel (refereegranskat)abstract
- Asthma, rhinitis and eczema (allergic or non-allergic) have increased throughout the world during the last decades, especially among children. Changes in the indoor environment are suspected to be important causes. China has experienced a dramatic change in indoor environmental exposures during the past two decades. However, such changes and their associations with children's asthma and other health aspects have not been thoroughly studied. China, Children, Homes, Health (CCHH), Phase I, was a cross-sectional questionnaire survey of 48219 children 1-8 years old in 10 Chinese cities during 2010-2012. The questionnaire includes the International Study of Asthma and Allergies in Childhood (ISAAC) core health questions and additional questions regarding housing, life habits and outdoor environment. In health analyses, children aged 3-6 years old were included. The prevalences of doctor diagnosed asthma varied from 1.7% to 9.8% (mean 6.8%), a large increase from 0.91% in 1999 and 1.50% in 2000. The prevalence of wheeze, rhinitis and atopic eczema (last 12 months) varied from 13.9% to 23.7%, 24.0% to 50.8% and 4.8% to 15.8%, respectively. Taiyuan had the lowest prevalences of all illnesses and Shanghai the highest, except for wheezewhere the highest value was for Urumqi. We found (1) no obvious association between disease prevalences and ambient PM10 concentrations and (2) higher prevalences of disease in humid climates with hot summers and cold winters, but with no centrally heated buildings. Associations between the diseases and economic status as indexed by Gross Domestic Product (GDP) requires further study.
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| 10. |
- Chen, Xiaohong, et al.
(författare)
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Hydrological Design of Nonstationary Flood Extremes and Durations in Wujiang River, South China : Changing Properties, Causes, and Impacts
- 2013
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Ingår i: Mathematical problems in engineering (Print). - : Hindawi Limited. - 1024-123X .- 1563-5147. ; , s. 527461-
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Tidskriftsartikel (refereegranskat)abstract
- The flood-duration-frequency (QDF) analysis is performed using annual maximum streamflow series of 1-10 day durations observed at Pingshi and Lishi stations in southern China. The trends and change point of annual maximum flood flow and flood duration are also investigated by statistical tests. The results indicate that (1) the annual maximum flood flow only has a marginally increasing trend, whereas the flood duration exhibits a significant decreasing trend at the 0.10 significant level. The change point for the annual maximum flood flow series was found in 1991 and after which the mean maximum flood flow increased by 45.26%. (2) The period after 1991 is characterized by frequent and shorter duration floods due to increased rainstorm. However, land use change in the basin was found intensifying the increased tendency of annual maximum flow after 1991. And (3) under nonstationary environmental conditions, alternative definitions of return period should be adapted. The impacts on curve fitting of flood series showed an overall change of upper tail from "gentle" to "steep," and the design flood magnitude became larger. Therefore, a nonstationary frequency analysis taking account of change point in the data series is highly recommended for future studies.
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