[Characteristics, Sources Apportionment, and Health Risks of PM2.5-bound PAHs and Their Derivatives Before and After Heating in Zibo City]

Atmospheric polycyclic aromatic hydrocarbons (PAHs) and their derivatives are a global problem that influences the environment and threatens human health. To investigate the characteristics, sources, and health risk assessment of PM2.5-bound PAHs and their derivatives, PM2.5 were collected at an urban site in Zibo from November 5 to December 26, 2020, and the concentrations of 16 conventional PAHs, nine NPAHs, and five OPAHs in PM2.5 were analyzed using gas chromatography-mass spectrometry. Source apportionment of PAHs and their derivatives was conducted using diagnostic ratios and a PMF model, and the health risks of PAHs and their derivatives to adult men and women were evaluated using the source-dependent incremental lifetime cancer risk (ILCR) model. The results showed that the average concentrations of ∑16pPAHs, ∑9NPAHs, and ∑5OPAHs in PM2.5 of Zibo City during the sampling period were (41.61 ± 13.40), (6.38 ± 5.70), and (53.20 ± 53.47) ng·m-3, respectively. The concentrations of the three PAHs increased significantly after heating, which were 1.31, 2.04, and 5.24 times larger than those before heating. During the sampling period, Chr, BaP, and BaA were the dominant components of pPAHs; 9N-Ant and 2N-Flt + 3N-Flt were the dominant components of NPAHs; and ATQ and BZO were the dominant components of OPAHs. Source apportionment results showed that motor vehicles were the main source of PAHs and their derivatives in PM2.5 before heating, whereas after heating, the main sources were the mixed source of coal and biomass combustion and secondary formation. The total BaP equivalent (TEQ) was 14.5 ng·m-3 during the sampling period, and the TEQ increased significantly after heating, which was approximately 1.2 times of that before heating. Assisted by the individual PAH source apportionment results, the ILCR of PM2.5-boundPAHs and NPAHs in Zibo City had a certain potential carcinogenic risk for adult males (1.06 × 10-5) and females (9.32 × 10-6). Among them, the health risks of PAHs from gasoline vehicles, diesel vehicles, and coal/biomass combustion were significantly higher than those from other emission sources.

[Research on the formulation and revision of radiological parameters in the "Standards for Drinking Water Quality（GB5749-2022）" in China]

The radioactive safety of drinking water has attracted increasing public concern. The newly issued Standards for Drinking Water Quality (GB5749-2022) in China has revised the radiological parameters. This article provides an overview of the main sources, levels of radionuclides in drinking water, and summarized the individual doses criterion and adverse health effects associated with exposure of the public to radionuclides from drinking-water. It analyzes and discusses the relevant revision content of radiological parameters, including the guidance values for screening gross α and gross β, subtracting the contribution of potassium-40 from gross β activity when the gross β activity concentration exceeds the screening level, and the basis for establishing the limit values of reference indices uranium and radium-226. Specific implementation and evaluation suggestions are also proposed.

[Evaluation of peripheral blood T-lymphocyte subpopulations features in patients with hepatitis B virus-related acute-on-chronic liver failure based on single-cell sequencing technology]

Objective: T lymphocyte exhaustion is an important component of immune dysfunction. Therefore, exploring peripheral blood-exhausted T lymphocyte features in patients with hepatitis B virus-related acute-on-chronic liver failure may provide potential therapeutic target molecules for ACLF immune dysfunction. Methods: Six cases with HBV-ACLF and three healthy controls were selected for T-cell heterogeneity detection using the single-cell RNA sequencing method. In addition, exhausted T lymphocyte subpopulations were screened to analyze their gene expression features, and their developmental trajectories quasi-timing. An independent sample t-test was used to compare the samples between the two groups. Results: Peripheral blood T lymphocytes in HBV-ACLF patients had different differentiation trajectories with different features distinct into eight subpopulations. Among them, the CD4(+)TIGIT(+) subsets (P = 0.007) and CD8(+)LAG3(+) (P = 0.010) subsets with highly exhausted genes were significantly higher than those in healthy controls. Quasi-time analysis showed that CD4(+)TIGIT(+) and CD8(+)LAG3(+) subsets appeared in the late stage of T lymphocyte differentiation, suggesting the transition of T lymphocyte from naïve-effector-exhausted during ACLF pathogenesis. Conclusion: There is heterogeneity in peripheral blood T lymphocyte differentiation in patients with HBV-ACLF, and the number of exhausted T cells featured by CD4(+)TIGIT(+)T cell and CD8(+)LAG3(+) T cell subsets increases significantly, suggesting that T lymphocyte immune exhaustion is involved in the immune dysfunction of HBV-ACLF, thereby identifying potential effective target molecules for improving ACLF patients' immune function.

[Agricultural Ammonia Emission Inventory and Its Distribution in Xining City]

Based on the field research activity level, the emission inventory of agricultural ammonia in Xining City in 2018 was established using the emission factor method. The emission characteristics of agricultural ammonia in Xining City were analyzed, a spatial grid distribution of 3 km×3 km was carried out by ArcGIS, and an uncertainty analysis of the ammonia emission inventory of livestock and poultry breeding and nitrogen fertilizer application was carried out via Monte Carlo simulation. The results showed that the total amount of ammonia emissions from agricultural sources in Xining City in 2018 was 4644.58 t. Among them, the total annual ammonia emissions from nitrogen fertilizer application and livestock and poultry farming were 1664.84 t and 2979.75 t, respectively, accounting for 35.84% and 64.16% of the total ammonia emissions from agricultural sources in Xining City. The spatial distribution results showed that the agricultural source ammonia emissions of Xining City mainly came from Datong County, Huangyuan County, and Huangzhong County, which accounted for 40.10%, 30.66%, and 28.05% of the total agricultural source ammonia emissions of Xining City, respectively. From the perspective of monthly distribution, no monthly difference in ammonia emissions was found in livestock and poultry farming. The ammonia emissions from nitrogen fertilizer application mainly existed in June (799.96 t) and July (768.48 t), accounting for 48.05% and 46.16% of the annual emissions. Monte Carlo simulation results showed that under a 95% confidence interval, the uncertainties of ammonia emissions from nitrogen fertilizer application agricultural source ammonia were low, ranging from -24.38% to 26.71%.

[Characteristics and Source Apportionment of Carbon Components in Road Dust in Anshan]

In order to study the characteristics and sources of carbon fractions in PM_2.5 in road dust in Anshan, road dust samples were collected from nine roads in Anshan in October 2014 and re-suspended on filters using a NK-ZXF sampler to obtain PM_2.5 samples. A thermal optical carbon analyzer (IMPROVE-TOR) was employed to measure the mass fraction of organic carbon (OC) and elemental carbon (EC) in PM_2.5. The results showed that ω(TC) in PM_2.5 in road dust was 9.78% (outer loop)-14.00% (Qianshan West Road), ω(OC) was 8.15% (outer loop)-10.84% (Qianshan West Road), and ω(EC) was 1.63% (outer loop)-2.85% (Qianshan West Road). ω(OC) was much higher than ω(EC), indicating that road dust contained a large amount of organic carbon. All OC/EC values were greater than 2.0 during the sampling period, suggesting that there was secondary pollution. Spearman correlation analysis and linear fitting indicated that the sources of OC and EC were basically the same. Cluster analysis results showed that carbon components in PM_2.5 in road dust in Anshan mainly originated from vehicle exhaust, biomass burning, and coal combustion emissions.

[Factors associated with fatigue in the employees of internet companies]

Objective: To explore factors associated with fatigue in employees working in Internet companies. Methods: A cross-sectional study was conducted among 3603 employees from 35 internet companies. A self-conducted questionnaire was used to assess employees' fatigue and related factors. Results: The scores of body fatigue, mental fatigue and total fatigue were (4.53±2.56) , (2.37±1.64) , and (6.90±3.55) respectively. The body fatigue is positively correlated with job burnout and musculoskeletal disorders (r=0.426, 0.485) ; the mental fatigue is positively correlated with job burnout (r=0.429) . JDC and ERI occupational stress, burnout and high level of musculoskeletal disorders increased the risk of body fatigue of which odds ratios are 1.58, 1.72, 4.08 and 5.91; odds ratios for the risk of mental fatigue are 1.73, 1.37, 2.61 and 2.08. Sleep time over 7 hours reduces the risk of fatigue (P<0.05) with odds ratio of 0.61 and 0.62. Conclusion: Employees of Internet companies is facing fatigue issues. To protect employee's physical and mental health is highly important for employers to alleviate fatigue and improve work performance.

[Characteristics and Source Apportionment of Carbon Components in Road Dust PM2.5 and PM10 During Spring in Tianjin Derived by Using the Quadrat Sampling Method]

In order to study the characteristics and sources of carbon fractions in PM_2.5 and PM₁₀ of road dust in Tianjin, samples of road dust were collected by the quadrat sampling method in April 2015 in Tianjin, and samples were re-suspended on filters by using a NK-ZXF sampler. A Thermal Optical Carbon Analyzer (IMPROVE-TOR) was employed to measure the concentrations of organic carbon (OC) and elemental carbon (EC), and the pollution characteristics and sources were investigated by non-parametric tests and OC/EC ratio, correlation, and cluster analyses. The results showed that ω(total carbon, TC) in PM_2.5 of road dust amounted to 4.89% (secondary road) -18.83% (expressway), ω(OC) amounted to 3.57% (secondary road) -15.39% (expressway), and ω(EC) amounted to 1.32% (secondary road) -3.44% (expressway); meanwhile, ω(TC) in PM₁₀ of road dust was 8.14% (secondary road) -19.71% (expressway), ω(OC) was 5.91% (secondary road) -16.28% (expressway), and ω(EC) was 1.96% (main road) -3.43% (expressway). The mass fraction of each carbon component for the expressway was relatively high, and that for the secondary trunk road was relatively low, which may have been due to the large traffic volume on the expressway and corresponding large amounts of exhaust emissions from motor vehicles, whereas there were fewer vehicles on the secondary trunk road. Additionally, ω(OC) was significantly larger than ω(EC) for all types of roads, and ω(EC) did not vary much among the different road types. The non-parametric tests of two related samples showed that there was no significant difference in the mass fraction of each carbon component between PM_2.5 and PM₁₀. The correlation analysis showed that the sources of OC and EC in road dust were roughly the same. The OC/EC ratio analysis and cluster analysis showed that the main sources of the carbon components in the dust of roads in Tianjin in spring were coal combustion, motor vehicle exhaust, and biomass burning.

[Protective effect of picroside Ⅱ on the brain tissue through antioxidation in stroke rats]

Objective: To investigate the effect and mechanisms of picroside Ⅱ on the brain tissue after cerebral ischemia reperfusion(I/R) in rats. Methods: The middle cerebral artery occlusion(MCAO) rat model was established by inserting a monofilament into middle cerebral artery. The experimental rats were treated by injecting picroside Ⅱ intraperitoneally. The modified neurological severity score (mNSS) and body weight were determined before modeling and after reperfusion of 22 h. The cerebral infarct volume was measured by TTC staining and the cerebral water content was measured in rats. At the same time, ROS content and NADPH oxidase activity were detected. The structure of neurons was observed by electron microscope and the mRNA and protein levels of Rac-1 and Nox2 were detected by RT-PCR and Western blotting. Results: After modeling, the mNSS score was significantly increased (12.6±1.3 vs 0, P<0.001), while the body weight was lost (13.3%±2.5% vs 4.9%±0.8%, P<0.01). The cerebral infarct volume increased obviously (33.5%±3.4% vs 0, P<0.001), brain water content increased significantly (81.5%±0.9% vs 77.7%±0.9%, P<0.05) and the structure of neuron was damaged obviously. The protein and mRNA levels of Rac-1 and Nox2 were significantly increased (P<0.05). After treatment with picroside Ⅱ, mNSS score decreased significantly (7.9±0.8 vs 12.6±1.3, P<0.05) and the body weight increased obviously (9.3%±1.1% vs 13.3%±2.5%, P<0.05). The infarct volume of brain was significantly reduced (18.2%±1.9% vs 33.5%±3.4%, P<0.05), brain water content decreased obviously (79.1%±0.7% vs 81.5±0.9%, P<0.05), the morphological structures of neurons was restored, and the expressions of Rac-1 and Nox2 were significantly decreased (P<0.05). Conclusion: It is suggested that picroside Ⅱ could exert antioxidation to protect the brain tissue through inhibiting the expression of Rac-1 and Nox2.

[Association of occupational stress with job burnout and depression tendency in workers in Internet companies]

Objective: To investigate the association of occupational stress with job burnout and depression tendency in workers in Internet companies. Methods: From July to November, 2016, the cross-sectional method was used to perform a questionnaire survey of 3603 workers in 35 Internet companies in Beijing, Shandong Province, and Zhejiang Province in China, and the association of occupational stress with job burnout and depression tendency was analyzed. Results: Among these workers, 63.70% had occupational stress with job demand-control (JDC) and 34.60% had occupational stress with effort-reward imbalance (ERI) ; among the workers engaged in sales, 75.63% had occupational stress with JDC and 62.70% had occupational stress with ERI. Of all workers, 10.69% had job burnout, and among the workers engaged in sales, 22.12% had job burnout. Of all workers, 18.79% had the tendency of moderate-to-severe or severe depression, and among the workers engaged in sales, 46.13% had such tendency. Occupational stress with JDC increased the risk of job burnout and depression (odds ratio[OR]=3.52 and 1.85, P<0.05) , and occupational stress with ERI also increased the risk of job burnout and depression (OR=8.24 and 5.59, P<0.05) . In addition, irregular diet and insomnia were risk factors for job burnout; age ≥41 years, low income, sales position, working time spent on the screen ≥10 hours/day, insomnia, and poor self-evaluated health status were risk factors for depression tendency. Conclusion: Occupational stress with JDC and ERI increases the risk of job burnout and depression tendency, and among the workers in Internet companies, the workers engaged in sales have the most severe occupational stress, job burnout, and depression tendency.

[Characteristics and Sources of Carbon Components in PM2.5 During Autumn and Winter in Panjin City]

In order to study the pollution characteristics and sources of carbon in Panjin City during autumn and winter, PM_2.5 samples were collected at three monitoring points in October 2016 and January 2017. Pollution characteristics and sources of carbon components in PM_2.5 were analyzed by the OC/EC ratio method, EC tracer method, and principal component analysis method. The results showed that the PM_2.5 concentration exceeded the ambient air quality standard (GB 3095-2012) and that the average concentrations of OC and EC were 10.02 μg·m^-3 and 3.91 μg·m^-3 in autumn, respectively, and 16.04 μg·m^-3 and 5.62 μg·m^-3 in winter. According to the OC/EC ratio method, the OC/EC ratios were more than 2.0 during the sampling periods, indicating that there was secondary pollution in autumn and winter. Spearman correlation analysis and linear fitting indicated that the OC and EC sources were complex in development zones and that secondary school and cultural park areas may have similar sources during autumn and winter. SOC was quantitatively estimated by the EC tracer method, with concentrations of 7.21 μg·m^-3 and 23.07 μg·m^-3 in autumn and winter, respectively. The absolute and relative errors of SOC uncertainty were 0.98 μg·m^-3 and 14.00% in autumn, respectively, and 1.87 μg·m^-3 and 8.21% in winter. Based on the method of principal component analysis, the carbon components in autumn and winter were mainly derived from coal combustion, biomass burning, and vehicle exhaust.

[Characteristics and Source Apportionment of Water-soluble Ions in PM2.5 During Winter in Panjin]

In order to study the characteristics and source of water-soluble ions in PM_2.5 in Panjin, PM_2.5 samples were collected at three sites in January of 2017, and the levels of eight ions (Na⁺, Mg²⁺, Ca²⁺, K⁺, NH₄⁺, SO₄^2-, Cl^-, and NO₃^-) were determined by ICS-900 ion chromatograph. The characteristics of PM_2.5, the water-soluble ion concentration, SOR and NOR calculation, and ion balance calculation were investigated, and a principal component analysis was conducted. The results showed that the concentration of PM_2.5 and water-soluble ions followed a descending sequence of park > development zone > the second middle school. SO₄^2-, NO₃^-, and NH₄⁺ were the major components of the water-soluble ions at the three sampling sites. SOR and NOR values were all higher than 0.10, indicating that SO₄^2- and NO₃^- were mainly converted from SO₂ and NO_x. The ion balance calculation demonstrated that the cationic and anion equivalents in Panjin had great correlation in winter. Further study showed that the atmosphere in the development zone presented as neutral and that in the cultural park and the second middle school presented as partially alkaline. The principal component analysis further indicated that the water-soluble ions were mainly derived from fuel combustion, biomass burning, secondary particles, and re-suspended dust in winter.

[Characteristics and Source Apportionment of Water-soluble Inorganic Ions in Road Dust PM2.5 During Spring in Tianjin Using the Quadrat Sampling Method]

In order to collect comprehensive information regarding the characteristics and sources of the water-soluble inorganic ions in road dust (RD) PM_2.5 in Tianjin, samples of road dust were collected in April 2015 in Tianjin, and then re-suspended on filters using a NK-ZXF sampler. The concentrations of the major water-soluble inorganic ions were analyzed by ion chromatography. A correlation analysis, ratio method, and principal component analysis were used to analyze the sources of RD PM_2.5. The results showed that the total water-soluble inorganic ion concentration in Tianjin accounted for 6.13%±2.32%, varying with different road types. Na⁺, K⁺, Mg²⁺, and Ca²⁺ showed high homology. NO₃^-/SO₄^2- revealed that the main source of PM_2.5 was mostly attributed to fixed sources. The principal component analysis showed that the main sources of RD PM_2.5 in Tianjin were coal combustion, mobile sources, biomass burning, and construction dust.

[Characteristics of Elements in PM2.5 and PM10 in Road Dust Fall During Spring in Tianjin]

To explore the element pollution characteristics and sources of road dust fall, road dust fall samples were collected during spring in Tianjin and suspended to obtain PM_2.5 and PM₁₀, 16 elements were analyzed, and then their characteristics, sources, and similarities were studied by nonparametric tests, the coefficient of divergence, and enrichment factor. The results showed that the mass fraction (1%-20%) in sequential order of the elements in PM_2.5 and PM₁₀ in Tianjin road dust fall were Si > Al > Ca > Fe > Mg > K > Na. The coefficient of divergence of elements in PM₁₀ and PM_2.5 was 0.06, indicating that the elements profiles of PM₁₀ might be similar to PM_2.5. The elements of Cd and Cr in PM₁₀ and PM_2.5 were at a high level of enrichment degree, and Zn, Cu, Pb, and As showed significant enrichment. The main sources of the elements in PM₁₀ and PM_2.5 road dust fall in Tianjin were soil dust, construction dust, traffic dust (motor vehicle exhaust, tire wear, and brake wear), and coal combustion.

[Characteristics and Source Apportionment of Water-soluble Inorganic Ions in Road Dust PM2.5 in Selected Cities in Liaoning Province]

In order to collect comprehensive information on the characteristics and sources of water-soluble inorganic ions in road dust (RD) PM_2.5 in Liaoning Province, samples of road dust were collected in 2014 and 2016 in Anshan and Panjin and then re-suspended on filters using an NK-ZXF sampler. The concentrations of the major water-soluble inorganic ions were analyzed by ion chromatography. A correlation analysis, ratios, and a principal component analysis were used to analyze the sources of RD. The results showed that the total water-soluble inorganic ions in Panjin and Anshan accounted for 5.83%±3.34% and 5.84%±1.15% in RD PM_2.5, respectively. NH₄⁺, SO₄^2-, and NO₃^- in RD PM_2.5 coexisted in the forms of (NH₄)₂SO₄, and NH₄NO₃ in Panjin, and NH₄HSO₄ and NH₄NO₃ in Anshan. The average values of NO₃^-/SO₄^2- were 0.52±0.55 and 0.46±0.13 for Panjin and Anshan, respectively, indicating that the effects of stationary sources (e.g., coal combustion) on PM_2.5 were more significant. The main sources of RD PM_2.5 in Panjin were biomass burning, sea salt particles, construction dust, and mobile sources, while the main sources of RD PM_2.5 in Anshan were coal combustion, biomass burning, sea salt particles, and steel smelting dust.

Robust generation of entangled state via ground-state antiblockade of Rydberg atoms

We propose a mechanism of ground-state antiblockade of Rydberg atoms, which is then exploited to prepare two-atom entangled state via three different kinds of pulses. First we use the pulses in the form of sin2 and cos2 functions and obtain a maximally entangled state at an accurate interaction time. Then the method of stimulated Raman adiabatic passage (STIRAP) is adopted for the entanglement generation, which is immune to the fluctuations of revelent parameters but requires a long time. Finally we capitalize the advantages of the former two methods and employ shortcuts to adiabatic passage (STAP) to generate the maximal entanglement. The strictly numerical simulation reveals that the current scheme is robust against spontaneous emission of atoms due to the virtual excitation of Rydberg states, and all of the above methods favor a high fidelity with the present experimental technology.

[Study of neuron-protective effect and mechanism of neuregulin1β against cerebral ischemia reperfusion-induced injury in rats]

Objective: Thecurrent study is to explore the neuron-protective mechanism of neuregulin1β (NRG1β) in a rat model of middle cerebral artery occlusion/reperfusion (MCAO/R) through inhibiting the c-Jun phosphorylation. Methods: After 24 h of MCAO/R (referring to Longa's method), neurobehavioral function was measured by modified neurological severity score (mNSS) test; the cerebral infarction volume was detected by triphenyltetrazolium chloride (TTC) staining; the blood brain barrier (BBB) permeability was measured by Evans Blue (EB); the neuron morphology of brain tissue was observed by Nissl stain; the ultra-structures of the neurons were observed by transmission electron microscopy (TEM); the apoptotic neurons were counted by in situ cell death detection kit colocalized with NeuN; the expressions of phospho-c-Jun was determined by immunofluorescent labeling and Western blot analysis. Results: Compared with the sham-operation rats, the rats receiving MCAO/R showed increased mNSS (9.7±1.2), cerebral infarction volume (41.4±3.0)%, permeability of BBB, deformation of neurons, ischemia-induced apoptosis (0.63±0.04), and enhanced expression of phospho-c-Jun protein (0.90±0.07) (all P<0.05). Our data indicated that NRG1β attenuated neurologic deficits (6.4±0.9), decreased the cerebral infarction volume (10.4±0.5), reduced EB extravasation (1.55±0.13) and the deformation of neurons, protected the ultra-structure of neurons, blocked ischemia-induced apoptosis (0.23±0.02), through down-regulated phospho-c-Jun expression (0.40±0.03) in MCAO/R rats (P<0.05). Conclusion: NRG1β exerts neuron-protective effects against ischemia reperfusion-induced injury in rats through inhibiting the c-Jun phosphorylation.

Conversion of entangled states with nitrogen-vacancy centers coupled to microtoroidal resonators

We propose efficient schemes for converting three-photon, four-photon and five-photon GHZ state to a W state or Dicke state, respectively with the nitrogen-vacancy (N-V) centers via single-photon input-output process and cross-Kerr nonlinearities. The total success probability can be improved by iterating the conversion process for the case of three-photon and five-photon while it does not require iteration for converting four-photon GHZ state to a W state. The analysis of feasibility shows that our scheme is feasible for current experimental technology.

Fusing atomic W states via quantum Zeno dynamics

We propose a scheme for preparation of large-scale entangled W states based on the fusion mechanism via quantum Zeno dynamics. By sending two atoms belonging to an n-atom W state and an m-atom W state, respectively, into a vacuum cavity (or two separate cavities), we may obtain a (n + m - 2)-atom W state via detecting the two-atom state after interaction. The present scheme is robust against both spontaneous emission of atoms and decay of cavity, and the feasibility analysis indicates that it can also be realized in experiment.

[Occupational stress in assembly line workers in electronics manufacturing service and related influencing factors]

Objective: To investigate occupational stress in assembly line workers in electronics manu-facturing service (EMS) and related influencing factors. Methods: From June to October, 2015, a cross-sectional survey was performed for 5 944 assembly line workers in EMS (observation group) and 6 270 workers from other posts (non-assembly line workers and management personnel; control group) using the self-made questionnaire for basic information, job demand-control (JDC) model questionnaire, and effort-reward imbalance (ERI) model questionnaire to collect respondents' basic information and occupational stress. Results: The observation group had significantly lower work autonomy, social support, and work reward scores than the control group (2.72 ± 0.63/3.64 ± 0.68/4.06 ± 0.80 vs 3.00 ± 0.67/3.83 ± 0.68/4.24 ± 0.75, t=23.53, 15.41, and 12.70, all P<0.05) , as well as significantly higher work effort and job involvement scores than the control group (2.34±0.78/2.48±0.78 vs 2.21±0.80/2.33±0.77, t=-9.08 and-10.90, both P<0.05). The observation group had significantly higher proportions of workers with occupational stress determined by JDC and ERI models than the control group (64.5%/12.7% vs 52.6%/9.9%, χ²=182.26 and 23.41, both P<0.05). Female sex, migrant workers, working time >60 hours/week, and sleeping time <7 hours/day were major risk factors for occupational stress in JDC model; education background of Bachelor's degree or above, working time >60 hours/week, and sleeping time<7 hours/day were major risk factors for occupational stress in ERI model, while female sex and a high monthly income reduced the risk of occupational stress in ERI model. Conclusion: Assembly line workers in EMS are a relatively vulnerable group and have a high degree of occupational stress. Working time >60 hours/week and sleeping time <7 hours/day are major risk factors for occupational stress.

[Occupational stress and early health effects in migrant workers in an electronics manufacturing service enterprise]

Objective: To investigate occupational stress in migrant workers in an electronics manufacturing service enterprise and the association between occupational stress and early health effects, such as job burnout, depressive tendency, and insomnia. Methods: In August 2015, stratified random cluster sampling was used to select 1 097 migrant workers in an electronics manufacturing service enterprise. The Job Demand-Autonomy Questionnaire and effort-reward imbalance questionnaire were used to investigate occupational stress with the types of high workload and effort-reward imbalance, and Burnout Inventory, depression scale, and self-management sleep questionnaire were used to investigate the early health effects of occupational stress. Results: In these migrant workers, the detection rates of occupational stress with the types of high workload and effort-reward imbalance were 69.8%(766/1 097) and 11.9%(131/1 097). The multivariate logistic regression analysis showed that the workers who had occupational stress with the types of high workload and effort-reward imbalance had significantly higher risks of job burnout and depressive tendencies than those who did not have these two types of occupational stress (P<0.01). The workers who had occupational stress with the type of effort-reward imbalance had a significantly higher ability to predict the risks of job burnout and depressive tendencies than those who had occupational stress with the type of high workload (P<0.01) , as well as a significantly higher risk of insomnia than those who did not have this type of occupational stress (P<0.01). Conclusion: Occupational stress is the major influencing factor for early health effects, such as job burnout, depressive tendency, and insomnia, in the migrant workers in this electronics manufacturing service enterprise. The workers who have occupational stress with the type of effort-reward imbalance have higher risks of job burnout and depressive tendencies than those who have occupational stress with the type of high workload.

[Analysis of correlation between pulmonary function and expression levels of matrix metalloproteinases-9 and tissue inhibitor of metalloproteinase-1 among toluene diisocyanate exposed workers]

OBJECTIVE

To investigate the effect of occupational toluene diisocyanate(TDI) exposure on matrix metalloproteinases-9 (MMP-9) and tissue inhibitor of metalloproteinase-1(TIMP-1), and analysis of the correlation of MMP-9,TIMP-1,MMP-9/TIMP-1 and lung function.

METHODS

In October 2014, based on cluster sampling, we conducted a cross-sectional study in a TDI production factory located in China's western region. 61 exposed workers were recruited from workers engaged in packing, operating and checking. Based on different levels of the external exposure, the packers were classified as high exposed group, while operators and checkers as low exposed group. 58 factory managers, matching age and agent, were selected as controls, having same work intense and not contacting the TDI or other allergens. The questionnaire surveys were used to obtain the agent, age, work age, smoking and drinking, personal and family allergic history, occupational history, and the recent health conditions. The levels of MMP-9 and TIMP-1 in serum of subjects were determind by ELISA. The time weighted average concentrations (8h-TWA) were used to describe the levels of TDI air exposure in working environment. Spearman correlation assay was used to investigate the correlation of MMP-9, TIMP-1, MMP-9/TIMP-1 and lung function, exposure time.

RESULTS

8-hour TWA means of TDI air levels in exposed group, packers, operators and checkers were 0.39, 0.76, 0.25 mg/m(3), respectively . According to the external exposure concentration, the packers were classified as high exposed group, and the operators and checkers were classified as low exposed group. In controls, low exposed group and high exposed group, the levels of MMP-9, respectively, were (807.21±347.70),(586.91±317.50),(388.94±312.01) ng/ml (χ(2)=16.69, P<0.001), respectively, and the P50(P25-P75) of MMP-9/TIMP-1 were 4.67(2.87-6.68), 2.3(1.44-3.48), 1.11(0.59-1.48) (χ(2)=39.42, P<0.001), respectively, and the concentrations of TIMP-1, were (173.44±72.67), (236.12±51.98), (302.81±44.39) ng/ml (F=20.09, P< 0.001), respectively. The levels P50(P25-P75) of FVC, FEV1.0 and FEV1.0/FVC in exposed group were, 92.8% (86.0%-101.8%), 85.5%(76.7%-92.8%), 112.5(108.2-118.5), respectively, which were lower than that in control group (124.3%(107.9%-144.2%), 142.7%(119.1%-155.7%), 129.2(123.5-134))(Z values were 7.70, 8.97, 8.62, and all P<0.001). Spearman rank correlation analysis showed that levels of MMP-9 were positively associated with FEV1.0, and FEV1.0/FVC (r values were 0.27, 0.25, respectively, all P<0.05), and The levels of TIMP-1 were negatively associated with FVC, FEV1.0, and FEV1.0/FVC (r valuse were -0.33, -0.39, -0.39, all P<0.05).The levels of MMP-9 were negatively correlated with exposure time(r=-0.26, P=0.040). The positive correlations of MMP-9/TIMP-1 with FVC, FEV1.0, and FEV1.0/FVC were also found (r valuse were 0.34, 0.44, 0.40, all P<0.05).

CONCLUSION

TDI exposure could induce the downs of MMP-9 and MMP-9/TIMP-1 associated with lung functions. The MMP-9 and MMP-9/TIMP-1,in a way, could reflect the respiratory inflammatory injury caused by TDI exposure.

[Determining the concentration of coating solution attaching to honeycomb denuder in summer in Tianjin]

The study on determining the concentration of coating solution attaching to honeycomb denuder was conducted, from 1 July to 31 August, 2013, at the roof of Lihua building at Nankai University in Tianjin. The results of experiment showed that the optimized concentration of sodium carbonate coated on the honeycomb denuder was 3%, and the optimized concentration of citric acid was 6%. The contrast sampling results of PM2.5 between honeycomb denuder system and conventional method showed that 86% of the concentration of PM2.5 samples obtained by honeycomb denuder system were less than those obtained by conventional method, the main reasons may include that: (1) the majority of acid/alkaline gases were removed, so they could neither react with the enriched particles on the sampling membrane nor be adsorbed on particles; (2) parts of the particles were captured by the denuder during sampling; (3) the removal of acid/alkaline gases disturbed the state of equilibrium between gas- and particle-phases which may lead to the volatilization of some particles.

[Carbon source apportionment of PM2.5 in Chongqing based on local carbon profiles]

PM2.5 was sampled from commercial, industrial and residential areas in Chongqing urban city from 2nd May to 10th May 2012 in order to find out characteristics and sources of carbon in PM2.5. Eight kinds of carbons were analyzed by the TOR method. Characteristics of carbon pollution in PM2.5 from three kinds of functional areas and six kinds of sources, including coal-combustion, exhausts (vehicle, boat and construction machine), biomass burning, cooking smoke, were analyzed. Based on carbon source profiles, local indicating components of carbon sources in PM2.5 were obtained used the chemical mass balance (CMB) model. Contribution rate of different sources to PM2.5 carbon were parsed out by factor analysis. The results showed the OC/EC of coal-combustion, vehicle exhausts, boat exhausts, construction machine exhausts, biomass burning and cooking smoke were 6.3, 3.0, 1.9, 1.4, 12.7 and 31.3, respectively. High loads of EC2 and EC3 indicated diesel vehicle exhaust emissions, high loads of OC2, OC3, OC4 and OPC indicated coal-combustion emissions, OC1, OC2, OC3, OC4 and EC1 indicated gasoline vehicle exhaust emissions, OC3 indicated cooking emissions, and OPC indicated biomass burning emissions. OC/PM2.5, EC/PM2.5, secondary organic carbon (SOC)/OC in the commercial area were 17.4%, 6.9% and 40.0%, respectively. OC/PM2.5, EC/PM2.5 and SOC/OC in the industrial area were 15.5%, 6.6% and 37.4%, respectively. OC/PM2.5, EC/PM2.5 and SOC/OC in the residential area were 14.6% 5.6% and 42.8%, respectively. In the industrial area, the main sources of carbon in PM2.5 were coal combustion, gasoline vehicle exhausts and diesel exhaust. In the commercial area, the main sources of carbon were gasoline vehicle exhausts, diesel exhausts and cooking. In the residential area, the main sources of carbon were gasoline vehicle exhausts, cooking smoke and diesel exhausts.

[Estimation of the effect derived from wind erosion of soil and dust emission in Tianjin suburbs on the central district based on WEPS model]

Due to the lack of a prediction model for current wind erosion in China and the slow development for such models, this study aims to predict the wind erosion of soil and the dust emission and develop a prediction model for wind erosion in Tianjin by investigating the structure, parameter systems and the relationships among the parameter systems of the prediction models for wind erosion in typical areas, using the U.S. wind erosion prediction system (WEPS) as reference. Based on the remote sensing technique and the test data, a parameter system was established for the prediction model of wind erosion and dust emission, and a model was developed that was suitable for the prediction of wind erosion and dust emission in Tianjin. Tianjin was divided into 11 080 blocks with a resolution of 1 x 1 km2, among which 7 778 dust emitting blocks were selected. The parameters of the blocks were localized, including longitude, latitude, elevation and direction, etc.. The database files of blocks were localized, including wind file, climate file, soil file and management file. The weps. run file was edited. Based on Microsoft Visualstudio 2008, secondary development was done using C + + language, and the dust fluxes of 7 778 blocks were estimated, including creep and saltation fluxes, suspension fluxes and PM10 fluxes. Based on the parameters of wind tunnel experiments in Inner Mongolia, the soil measurement data and climate data in suburbs of Tianjin, the wind erosion module, wind erosion fluxes, dust emission release modulus and dust release fluxes were calculated for the four seasons and the whole year in suburbs of Tianjin. In 2009, the total creep and saltation fluxes, suspension fluxes and PM10 fluxes in the suburbs of Tianjin were 2.54 x 10(6) t, 1.25 x 10(7) t and 9.04 x 10(5) t, respectively, among which, the parts pointing to the central district were 5.61 x 10(5) t, 2.89 x 10(6) t and 2.03 x 10(5) t, respectively.

[Estimation of the effect derived from Tianjin suburban wind erosion open source on central district]

In some Chinese cities air pollution is serious, and the major pollutant is still PM10. The source apportionment results show: wind erosion dust is an important source of particulate matter. So the contribution of this source should be calculated. The suburban land of Tianjin was classified based on Landsat TM satellite image, and samples of different land use types were taken. The soil textures were determined with the analysis of soil samples by the laser particle analyzer and GIS-based interpolation computation. The wind erosion modulus, wind erosion fluxes, dust release modulus and dust release fluxes were calculated in four seasons in suburban of Tianjin (Beichen, Xiqing, Jinnan and Dongli). The wind erosion fluxes in spring, summer, autumn and winter were 21236.31, 4435.21, 7272.13 and 17204.4 t in 2009; the wind erosion fluxes in Beichen, Xiqing, Jinnan and Dongli were 6380.23, 32 881.13, 8 340.67 and 2 546.02 t in 2009; the wind erosion fluxes from cultivated land and forest grassland were 49 599.2 and 548.85 t, respectively. The soil dust release fluxes in Tianjin suburban were 9 352.92 t (particle size < 10 microm), 20 587.99 t (particle size 10-15 microm)and 13 873.74 t (particle size 15-20 microm). In 2009, there were 20 592.91 t soil dusts with particulate diameter of 20 microm or less that were transmitted from suburban to central district, and 4 395.89 t with particulate diameter of 10 microm or less, about 21.35%.

Determination of traces of 237Np in environmental samples by ICP-MS after separation using TOA extraction chromatography

A simple, rapid, cost-efficient, and robust method for separation of 237Np with an extraction chromatographic column (TOA: tri-n-octylamine on Teflon powder) is outlined in detail and further improved for direct ICP-MS analysis. The column efficiently retained 237Np in 2 mol L(-1) HNO3 medium and all of the 237Np was easily eluted with 0.02 mol L(-1) oxalic acid in 0.16 mol L(-1) HNO3 at 95 degrees C. The separated solutions were free from most matrix elements and were aspirated into the ICP-MS directly. The decontamination factor for 238U is more than 10(4). The instrumental detection limit for 237Np was 0.46 pg mL(-1), which corresponds to 1.2 x 10(-5) Bq mL(-1). The method is more rapid than traditional radiometric techniques. It is also considered to be more suitable for environmental monitoring than existing methods based on TOA.