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The burden of disease attributed to the indoor exposure to sulfur dioxide (SO

The last two decades have witnessed rapid urbanization and economic growth accompanied by severe indoor air pollution of volatile organic compounds (VOCs) in China. However, indoor VOC pollution across China has not been well characterized and documented. This study is a systematic review of field measurements of eight target VOCs (benzene, toluene, xylenes, acetaldehyde, p-dichlorobenzene, butadiene, trichloroethylene, and tetrachloroethylene) in residences, offices, and schools in China from 2000 to 2021. The results show that indoor pollution of benzene, toluene, and xylenes has been more serious in China than in other countries. Spatiotemporal distribution shows lower indoor VOC levels in east and south-east regions and a declining trend from 2000 to 2021. Moving into a dwelling more than 1 year after decoration and improving ventilation could significantly reduce exposure to indoor VOCs. Reducing benzene exposure is urgently needed because it is associated with greater health risks (4.5 × 10

Exposure to volatile organic compounds (VOCs) indoors is thought to be associated with several adverse health effects. However, we still lack concentration-response (C-R) relationships between VOC levels in civil buildings and various health outcomes. For this paper, we conducted a systematic review and meta-analysis of observational studies to summarize related associations and C-R relationships. Four databases were searched to collect all relevant studies published between January 1980 and December 2017. A total of 39 studies were identified in the systematic review, and 32 of these were included in the meta-analysis. We found that the pooled relative risk (RR) for leukemia was 1.03 (95% CI: 1.01-1.05) per 1 μg/m

China's profoundly rapid modernization in the past two decades has resulted in dramatic changes in indoor environmental exposures. Among these changes, exposure to phthalates has attracted increasing attention. We aimed to characterize indoor phthalate exposure and to estimate the disease burden attributable to indoor phthalate pollution from 2000 to 2017 in China. We integrated the national exposure level of indoor phthalates from literature through systematic review and Monte Carlo simulation. Dose-response relationships between phthalate exposure and health outcomes were obtained by systematic review and meta-analysis. Based on existing models for assessing probabilities of causation and a comprehensive review of available data, we calculated the disability-adjusted life years (DALYs) among the general Chinese population resulting from exposure to indoor phthalate pollution. We found that DnBP, DiBP, and DEHP were the most abundant phthalates in indoor environments of residences, offices, and schools with medians of national dust phase concentration from 74.5 µg/g to 96.3 µg/g, 39.6 µg/g to 162.5 µg/g, 634.2 µg/g to 1,394.7 µg/g, respectively. The national equivalent exposure for children to phthalates in settled dust was higher than that of adults except for DiBP and DnOP. Dose-response relationships associated with DEP, DiBP, DnBP, BBzP, and DEHP exposures were established. Between 2000 and 2017, indoor phthalate exposure in China has led to 3.32 million DALYs per year, accounting for 0.90% of total DALYs across China. The annual DALY associated with indoor phthalate pollution in China was over 2000 people per million, which is about 2~3 times of the DALY loss due to secondhand smoke (SHS) in six European countries or the sum of the DALY loss caused by indoor radon and formaldehyde in American homes. Our study indicates a considerable socioeconomic impact of indoor phthalate exposure for a modernizing human society. This suggest the need for relevant national standard and actions to reduce indoor phthalate exposure.

In order to comprehensively evaluate the impact of fine particulate matter (PM2.5) exposure on public health in China, and to obtain a quantitative concentration–response relationship, the literature published in multiple databases from 1980 to 2019 was searched to obtain studies on the health effects of PM2.5 on the Chinese population in this paper. According to the inclusion and exclusion criteria, 67 studies were included in the research, which covered the study period from 2004 to 2018. A systematic review shows that there are 30 diseases and 46 health effect outcomes with clear concentration–response relationships with PM2.5 in China. Seven health effects were investigated by meta-analysis. For each 10 μg/m3 increase in PM2.5, the combined overall random-effects relative risk (RR) of non-accidental mortality, mortality due to cardiovascular disease, and mortality due to respiratory disease was 1.006 (95% CI = 1.004, 1.007), 1.007 (95% CI = 1.005, 1.008), and 1.008 (95% CI = 1.006, 1.010), respectively. The RR of hospital admission due to cardiovascular disease and respiratory disease was 1.006 (95% CI = 0.999, 1.014) and 1.006 (95% CI = 1.003, 1.010), respectively. In terms of outpatient visits, a 10 μg/m3 increase in PM2.5 corresponds to a 1.004 (95% CI = 1.002, 1.006) and 1.008 (95% CI = 1.005, 1.010) RR for cardiovascular disease and respiratory disease, respectively.

Climate change and human activities are closely linked with the nutrient accumulation in sediments, but the role of influence factors and the driving mechanisms are unclear. Here, by using the generalized additive model (GAM), we investigated the contributions and driving mechanisms of climate change and human activities on TON, TN, and TP accumulation in sediments of typical lakes in the Huai River basin (Nansi Lake and Hongze Lake) from 1988 to 2018. The impacts of factors, such as air temperature (AT), real GDP per capita (GDP), population density (PD), crop sown area (CSA), artificial impervious area (AIA), and domestic sewage discharge (DSD) were considered in this study. The results of the multivariate GAM showed that the sediment variables were significantly affected by climate change in Nansi Lake, but not in Hongze Lake. AT and DSD contributed the most to the variation of sediment TOC in Nansi Lake, while the most critical factors affecting TN and TP were AT, PD and DSD. PD and CSA showed strong ability to explain the change of TOC in Hongze Lake, while CSA and DSD showed strong ability to explain the variations of TN and TP. The results show that the selected optimal multivariate GAM can well quantify the effects of climate change and human activities on nutrient enrichment in lake sediments. Effective recommendations are provided for decision-makers in developing water quality management plans to prevent eutrophication outbreaks in lake waters by targeting and controlling key factors.

Microbes in buildings have attracted extensive attention from both the research community and the general public due to their close relationship with human health. However, there still lacks comprehensive information on the indoor exposure level of microbes in China. This study systematically reviews exposure levels, the community structures, and the impact factors of airborne bacteria and fungi in residences, schools, and offices in China. We reviewed the major literature databases between 1980 and 2019 and selected 55 original studies based on a set of criteria. Results show that the concentration of indoor bacteria varies from 72.5 to 7500 CFU/m3 , with a median value of 1000 CFU/m3 , and the concentration of fungi varies from 12 to 9730 CFU/m3 , with a median value of 526 CFU/m3 . The concentration level of microbes varies in different climate zones, with higher bacterial concentrations in the severe cold zone, and higher fungal concentrations in the hot summer and warm winter zone. Among different buildings, classrooms have the highest average bacteria and fungi levels. This review reveals that a unified assessment system based on health effects is needed for evaluating the exposure levels of bacteria and fungi.

Beijing has been the fastest-growing megacity in China, however it faced severe air pollution in recent years, particularly the notorious fine particulate matter (PM2.5). In response, Beijing increased the use of natural gas since 2008; therefore, natural gas consumption (NGC) soared rapidly, accounting for over 30% of total energy need in 2016. This study explores the long- and short-run effects of NGC on PM2.5 emissions within the framework of the environmental Kuznets curve (EKC) in Beijing by employing the autoregressive distributed lag (ARDL) approach. To do this, the long-term and monthly PM2.5 data based on ground monitoring are used for the period of April 2008 through December 2016 (2008 M04-2016 M12). The empirical results suggest, in the long run, an inverted U-shaped EKC link exists between PM2.5 emissions and per capita gross domestic product (GDP); with 16,973 yuan for per capita monthly GDP, the EKC will reach its peak. Although the NGC in Beijing can mitigate PM2.5 emissions in both the long run and short run, its mitigation effect would be weakened over time. Furthermore, increasing vehicle quantity would lead to higher concentrations of PM2.5, whereas the proportion of tertiary industry exerts a negative effect on PM2.5 in Beijing. At the end of the article, several key policy implications are highlighted both for mitigating PM2.5 and for promoting growth in natural gas industry in Beijing.

The aim of this study is to investigate the dynamic causal links among per capita carbon dioxide (CO2) emissions, per capita gross domestic product (GDP), per capita fossil fuels consumption, per capita nuclear energy consumption, and per capita renewable energy consumption within the framework of the environmental Kuznets curve (EKC) for the case of China. To do so, a series of econometric techniques allowing for structural break is utilized for the period of 1993–2016. The empirical results confirm the existence of the EKC for CO2 emissions in China. The estimated turning point (TP) of China's EKC for CO2 emissions is calculated as 96,680.47 yuan and is expected to reach its peak by approximately 2028. The empirical results also indicate that, in both the short and long run, nuclear energy and renewable energy play important roles in mitigating CO2 emissions, while fossil fuels consumption is indeed the dominant culprit for promoting CO2 emissions. Furthermore, the mitigation impact of nuclear energy consumption on CO2 emissions is considerably smaller than that of renewable energy consumption, implying that renewable energy will be the main contributor to CO2 emissions mitigation in China. Finally, several important policy implications for mitigating China's CO2 emissions and promoting growth in the nuclear energy and renewable energy industries are provided.

With the deteriorating air pollution in the urban areas of China, particularly the unprecedentedly high levels of smog, public demand for clean air is increasing. This study examines the values of public willingness to pay (WTP) for three smog mitigation scenarios in the urban areas of Beijing and investigates their determinants by employing the contingent valuation method (CVM) and interval regression model. The empirical results suggest that more than 80% of the respondents is willing to pay for smog mitigation. Respondents' WTP rises with an increasing smog mitigation percentage, and the amount of WTP for 30%, 45%, and 60% smog mitigation, respectively, is 615.13 CNY, 716.34 CNY, and 914.49 CNY, accounting for 0.55%, 0.64%, and 0.82% of their annual income. In contrast with other cities, the ratio of WTP to income in Beijing seems to situate inside a relatively moderate range. Moreover, respondents’ knowledge, risk perception, and attitude toward government are positively and significantly correlated with their WTP, and other determinants such as age, health condition, and annual income also significantly affect the value of WTP. We further recommend several important policy implications, which offer new evidence for developing specific policies to tackle smog pollution.

Fine particulate matter (PM2.5) pollution is of national concern in China. Indoor PM2.5 concentrations may contribute significantly to human exposure because people spend most of their time indoors. In this study, we systematically reviewed the level of indoor PM2.5 concentrations in residences, offices, and schools in China. We looked for corresponding literature published between 1980 and 2019 in six major literature databases and finally obtained 118 articles. We then summarized the spatial distribution of indoor PM2.5 concentrations in urban and rural areas, analyzed the indoor PM2.5 concentrations in residences, offices, and schools in urban areas across three time periods, and compared the indoor PM2.5 concentration levels in the urban and rural areas. It was found that the urban areas considered are mainly distributed in the middle and eastern part of China, while the rural areas are mainly distributed in northeast, north, and southwest China. Indoor PM2.5 concentrations have decreased significantly in the past decades. The mean ± SD value of indoor PM2.5 concentration decreased from 127.5 ± 111.4 μg/m³ prior to 2010 to 70.1 ± 35.2 μg/m³ following 2015. The indoor PM2.5 concentration in rural areas was much higher than that in urban areas. The mean ± SD value of indoor PM2.5 concentrations in rural residences was up to 275.7 ± 326.4 μg/m³, while that in urban residences was 95.4 ± 71.0 μg/m³. A long-term national indoor PM2.5 concentration measurement is suggested to obtain a more comprehensive and accurate indoor PM2.5 concentration level.

This study utilizes 1995–2014 panel data of the 30 provinces in China to investigate the existence of the environmental Kuznets curve (EKC) for carbon dioxide (CO 2 ) emissions in China. The potential impact of natural gas consumption on CO 2 emissions is also analyzed. According to the panel fully modified ordinary least squares (FMOLS) and panel dynamic OLS (DOLS) estimation results, in the long run, an inverted U-shaped EKC link exists between per capita CO 2 emissions and per capita gross domestic product (GDP). In the panel FMOLS model and panel DOLS model, with 99,261 yuan and 59,159 yuan for per capita GDP, the EKC of China will reach its peak by around 2029 or 2019, respectively. Furthermore, natural gas consumption has a significant negative impact on CO 2 emissions, which indicates that, 1% increase in natural gas consumption for the panel FMOLS model and panel DOLS model will decrease CO 2 emissions by 0.033627% or 0.054914%, respectively. At the provincial level, provinces in which the EKC hypothesis holds are predominantly concentrated in central and eastern China, and the energy consumption structure (share of natural gas in total energy consumption) may affect the occurrence of a significant negative impact of natural gas consumption on CO 2 emissions. Another finding of this study is that both the existence of EKC and the occurrence of a positive/negative impact of natural gas consumption on CO 2 emissions are independent of the individual provincial per capita GDP.

Obesity, which predisposes individuals to type II diabetes and cardiovascular diseases, results from accumulation of white adipose tissue (WAT). WAT comprises mainly white adipocytes that have a unique cellular structure in which almost the entire intracellular space is occupied by one single lipid droplet. The cytoplasm envelopes this lipid droplet and occupies negligible space. Differentiation of WAT, or adipogenesis, requires dramatic cytoplasmic reorganization, including a dynamic change in mitochondrial mass. Autophagy is a major cytoplasmic degradation pathway and a primary pathway for mitochondrial degradation. Recent studies indicate that autophagy is implicated in adipogenesis. In this review, we summarize our current knowledge on autophagy in adipose tissue biology, with the emphasis on its role in mitochondrial degradation. Adipose tissue is a central component for whole-body energy homeostasis regulation. Advancement in this research area may provide novel venues for the intervention of obesity and obesity related diseases.

Type 2 diabetes (T2D) has reached an epidemic level globally. Most current treatments ameliorate the hyperglycemic symptom of the disease but are not effective in correcting its underlying cause. One important causal factor of T2D is ectopic accumulation of lipids in metabolically sensitive organs such as liver and muscle. Mitochondrial uncoupling, which reduces cellular energy efficiency and increases lipid oxidation, is an appealing therapeutic strategy. The challenge, however, is to discover safe mitochondrial uncouplers for practical use. Niclosamide is an anthelmintic drug approved by the US Food and Drug Administration that uncouples the mitochondria of parasitic worms. Here we show that niclosamide ethanolamine salt (NEN) uncouples mammalian mitochondria at upper nanomolar concentrations. Oral NEN increases energy expenditure and lipid metabolism in mice. It is also efficacious in preventing and treating hepatic steatosis and insulin resistance induced by a high-fat diet. Moreover, it improves glycemic control and delays disease progression in db/db mice. Given the well-documented safety profile of NEN, our study provides a potentially new and practical pharmacological approach for treating T2D.

The dissociation and unfolding behavior of the GCN4 leucine zipper has been studied using SDS titration. Circular dichroism (CD) spectra showed that the alpha-helix content of the leucine zipper (20 microM) decreased during the sodium dodecyl sulfate (SDS) titration. However, the alpha-helix content of the leucine zipper still remained significant in the presence of 1 mM SDS, with little change detected when the SDS concentration further increased to 2 mM. The dimer dissociation of the leucine zipper is also a co-operative process during SDS titration; with no dimer remaining when SDS concentration reached 1 mM, as shown by electrophoresis and the the theta(222)/theta(208) ratio. Our results indicate that SDS efficiently induces leucine zipper dimer dissociation with the monomers still partially folded. The experimental results provide important evidence for the previous model that partial helix formation precedes dimerization in coiled coil folding.

The effects of zinc on creatine kinase (CK) are very distinctive compared with other bivalent metal ions. Zinc up to 0.1 mM induced increases in CK activity, accompanied by significant hydrophobic surface exposure and increase in alpha-helix content of CK. Zinc over 0.1 mM denatured and inactived CK. In the presence of 0.1 mM zinc, the CK activity was very close to that of the native CK, but its conformation changed greatly. The kinetic courses of CK inactivation and conformational change in the presence of 1 mM zinc were measured to determine apparent rate constants of inactivation and conformational change. Zinc over 0.05 mM induced CK aggregation at 37 degrees C, and the aggregation was dependent on zinc concentration, CK concentration, and temperature. The inactivation and aggregation can be reversed by EDTA. An explanation for CK aggregation induced by zinc is proposed, as well as a mechanism for CK abnormality in Alzheimer's disease.

Regulation of gene expression by many transcription factors is controlled by specific combinations of homo- and heterodimers through a short α-helical coiled-coil known as a leucine zipper. The dimer interface of a leucine zipper involves side chains of the residues at thea,d,e, andgpositions of the (abcdefg)nheptad repeat. To understand the basis for the specificity of dimer formation, we characterized GCN4 leucine zipper mutants with all 16 possible permutations and combinations of isoleucines and asparagines at fourapositions in the dimer interface, using a genetic test for the specificity of dimer formation by λ repressor-leucine zipper fusions. Heterodimers were detected by loss of repressor activity in the presence of a fusion to a dominant-negative mutant form of the DNA-binding domain of repressor. Reconstruction experiments using leucine zippers from GCN4, Jun, Fos, and C/EBP showed that this assay distinguishes pairs that form heterodimers from those that do not. We found that the mutants have novel dimerization specificities determined by the positioning of buried asparagine residues at theapositions. The pattern of buried polar residues could also explain the dimerization specificities of some naturally occurring leucine zippers. The altered specificity mutants described here should be useful for the construction of artificial regulatory circuitry.

Autophagy is an evolutionarily conserved cytoplasmic degradation pathway. A fundamental function of autophagy at the cellular level is to recycle cytoplasmic components, including macromolecules and organelles. Autophagy is essential for cell survival under nutrient deprived conditions. In addition, working in concert with other proteins in cells, the regulated and cargo-specific autophagic degradation is crucial for cellular maintenance and reducing cellular damage. Since the initial reports that autophagy is implicated in tumor suppression more than a decade ago, great advancements have been made in research on both autophagy and on its role in tumorigenesis. Here we summarize some of the important results from literature, mostly mouse genetics and human cancer genetics data. These data support a working model that autophagy suppresses tumorigenesis primarily in a cell-­intrinsic and indirect manner, most likely through reducing cellular damage by degrading some tissue-specific cell-damaging factors. In addition, non-cell autonomous processes triggered by autophagy defect may also contribute to tumor development. The current information on the unequivocal role of autophagy in suppressing tumorigenesis strongly favors future exploration in area of developing practical autophagy activating approaches for tumor chemoprevention.

Putative intersubunit electrostatic interactions between charged amino acids on the surfaces of the dimer interfaces of leucine zippers (g-e' ion pairs) have been implicated as determinants of dimerization specificity. To evaluate the importance of these ionic interactions in determining the specificity of dimer formation, we constructed a pool of > 65,000 GCN4 leucine zipper mutants in which all the e and g positions are occupied by different combinations of alanine, glutamic acid, lysine, or threonine. The oligomerization properties of these mutants were evaluated based on the phenotypes of cells expressing lambda repressor-leucine zipper fusion proteins. About 90% of the mutants do not form stable homooligomers. Surprisingly, approximately 8% of the mutant sequences have phenotypes consistent with the formation of higher-order (> dimer) oligomers, which can be classified into three types based on sequence features. The oligomerization states of mutants from two of these types were determined by characterizing purified fusion proteins. The Type I mutant behaved as a tetramer under all tested conditions, whereas the Type III mutant formed a variety of higher-order oligomers, depending on the solution conditions. Stable homodimers comprise less than 3% of the pool; several g-e' positions in these mutants could form attractive ion pairs. Putative repulsive ion pairs are not found among the homodimeric mutants. However, patterns of charged residues at the e and g positions do not seem to be sufficient to predict either homodimer or heterodimer formation among the mutants.

Chimeric proteins comprising the N-terminal DNA binding domain of λ repressor fused to a fragment of a foreign protein have been used to detect oligomerization of the latter. Fusions containing dimeric and tetrameric leucine zipper domains can be distinguished based on their in vivo repressor activities on a pair of cat-lacZ reporter strains. Repressor fusions are unable to efficiently repress transcription from a synthetic promoter that overlaps a weak operator site; repression by tetrameric, but not dimeric, fusion proteins is increased by the presence of a strong, upstream operator site. To construct reporters we developed a shuttle system that allows rapid construction of single-copy operon fusions in E. coli , with both cat and lacZ as reporters.