Obscured Contribution of Oxygenated Intermediate-Volatility Organic Compounds to Secondary Organic Aerosol Formation from Gasoline Vehicle Emissions.

Secondary organic aerosol (SOA) formation from gasoline vehicles spanning a wide range of emission types was investigated using an oxidation flow reactor (OFR) by conducting chassis dynamometer tests. Aided by advanced mass spectrometric techniques, SOA precursors, including volatile organic compounds (VOCs) and intermediate/semivolatile organic compounds (I/SVOCs), were comprehensively characterized. The reconstructed SOA produced from the speciated VOCs and I/SVOCs can explain 69% of the SOA measured downstream of an OFR upon 0.5-3 days' OH exposure. While VOCs can only explain 10% of total SOA production, the contribution from I/SVOCs is 59%, with oxygenated I/SVOCs (O-I/SVOCs) taking up 20% of that contribution. O-I/SVOCs (e.g., benzylic or aliphatic aldehydes and ketones), as an obscured source, account for 16% of total nonmethane organic gas (NMOG) emission. More importantly, with the improvement in emission standards, the NMOG is effectively mitigated by 35% from China 4 to China 6, which is predominantly attributed to the decrease of VOCs. Real-time measurements of different NMOG components as well as SOA production further reveal that the current emission control measures, such as advances in engine and three-way catalytic converter (TWC) techniques, are effective in reducing the "light" SOA precursors (i.e., single-ring aromatics) but not for the I/SVOC emissions. Our results also highlight greater effects of O-I/SVOCs to SOA formation than previously observed and the urgent need for further investigation into their origins, i.e., incomplete combustion, lubricating oil, etc., which requires improvements in real-time molecular-level characterization of I/SVOC molecules and in turn will benefit the future design of control measures.

Modeling the molecular composition of secondary organic aerosol under highly polluted conditions: A case study in the Yangtze River Delta Region in China.

A near-explicit mechanism, the master chemical mechanism (MCMv3.3.1), coupled with the Community Multiscale Air Quality (CMAQ) model (CMAQ-MCM-SOA), was applied to investigate the characteristics of secondary organic aerosol (SOA) during a pollution event in the Yangtze River Delta (YRD) region in summer 2018. Model performances in predicting explicit volatile organic compounds (VOCs), organic aerosol (OA), secondary organic carbon (SOC), and other related pollutants in Taizhou, as well as ozone (O3) and fine particulate matter (PM2.5) in multiple cities in this region, were evaluated against observations and model predictions by the CMAQ model coupled with a lumped photochemical mechanism (SAPRC07tic, S07). MCM and S07 exhibited similar performances in predicting gaseous species, while MCM better captured the observed PM2.5 and inorganic aerosols. Both models underpredicted OA concentrations. When excluding data during biomass burning events, SOC concentrations were underpredicted by the CMAQ-MCM-SOA model (-28.4 %) and overpredicted by the CMAQ-S07 model (134.4 %), with better agreement with observations in the trend captured by the CMAQ-MCM-SOA model. Dicarbonyl SOA accounted for a significant fraction of total SOA in the YRD, while organic nitrates originating from aromatics were the most abundant species contributing to the SOA formation from gas-particle partitioning. The oxygen-to­carbon ratio (O/C) for SOA and OA were 0.68-0.75 and 0.20-0.65, respectively, indicating a higher oxidation state in the areas influenced by biogenic emissions. Finally, the phase state of SOA was examined by calculating the glass transition temperature (Tg) based on its molecular composition. It was found that semi-solid state characterized SOA in the YRD, which could potentially impact their chemical transformation and lifetimes along with those of their precursors.

Characteristics of typical intermediate and semi volatile organic compounds in Shanghai during China International Import Expo event.

To ensure good air quality during the China International Import Expo (CIIE) event, stringent emission-reduction measures were implemented in Shanghai. To assess the efficacy of these measures, this study measured typical categories of intermediate/semi volatile organic compounds (I/SVOCs), including alkanes (C10-C26 n-alkanes and pristane), EPA-priority polycyclic aromatic hydrocarbons (PAHs), alkylnaphthalenes, benzothiazole (BTH) and chlorobenzenes (CBs), at an urban site of Shanghai before and during two CIIE events (2019 and 2020; non-CIIE versus CIIE). The average concentrations of alkanes and PAHs during both 2019 and 2020 CIIE events decreased by approximately 41% and 17%, respectively, compared to non-CIIE periods. However, the decline in BTH and CBs was only observed during CIIE-2019. Secondary organic aerosol (SOA) formation from alkanes, PAHs and BTH was evaluated under atmospheric conditions, revealing considerable SOA contributions from dimethylnaphthalenes and BTH. Positive matrix factorization (PMF) analysis further revealed that life-related sources, such as cooking and residential emissions, make a noticeable contribution (21.6%) in addition to the commonly concerned gasoline-vehicle sources (31.5%), diesel-related emissions (20.8%), industrial emissions (18.6%) and ship emissions (7.5%). These findings provide valuable insights into the efficacy of the implemented measures in reducing atmospheric I/SVOCs levels. Moreover, our results highlight the significance of exploring additional individual species of I/SVOCs and life-related sources for further research and policy development.

Predicting Atmospheric Particle Phase State Using an Explainable Machine Learning Approach Based on Particle Rebound Measurements.

The particle phase state plays a vital role in the gas-particle partitioning, multiphase reactions, ice nucleation activity, and particle growth in the atmosphere. However, the characterization of the atmospheric phase state remains challenging. Herein, based on measured aerosol chemical composition and ambient relative humidity (RH), a machine learning (ML) model with high accuracy (R2 = 0.952) and robustness (RMSE = 0.078) was developed to predict the particle rebound fraction, f, which is an indicator of the particle phase state. Using this ML model, the f of particles in the urban atmosphere was predicted based on seasonal average aerosol chemical composition and RH. Regardless of seasons, aerosols remain in the liquid state of mid-high latitude cities in the northern hemisphere and in the semisolid state over semiarid regions. In the East Asian megacities, the particles remain in the liquid state in spring and summer and in the semisolid state in other seasons. The effects of nitrate, which is becoming dominant in fine particles in several urban areas, on the particle phase state were evaluated. More nitrate led the particles to remain in the liquid state at an even lower RH. This study proposed a new approach to predict the particle phase state in the atmosphere based on RH and aerosol chemical composition.

Treatment of liver fibrosis in hepatolenticular degeneration with traditional Chinese medicine: systematic review of meta-analysis, network pharmacology and molecular dynamics simulation.

Background: Traditional Chinese medicine (TCM) is widely used in the clinical treatment of hepatolenticular degeneration (HLD) and liver fibrosis (LF). In the present study, the curative effect was assessed using meta-analysis. The possible mechanism of TCM against LF in HLD was investigated using network pharmacology and molecular dynamics simulation. Methods: For literature collection, we searched several databases, including PubMed, Embase, Cochrane Library, Web of Science, Chinese National Knowledge Infrastructure (CNKI), VIP Database for Chinese Technical Periodicals (VIP) and Wan Fang database until February 2023, and the Review Manager 5.3 was used to analyze the data. Network pharmacology and molecular dynamics simulation were used to explore the mechanism of TCM in treating LF in HLD. Results: The results of the meta-analysis revealed that the addition of Chinese herbal medicine (CHM) in treating HLD resulted in a higher total clinical effective rate than western medicine alone [RR 1.25, 95% CI (1.09, 1.44), p = 0.002]. It not only has a better effect on liver protection [Alanine aminotransferase: SMD = -1.20, 95% CI (-1.70, -0.70), p < 0.00001; Aspartate aminotransferase: SMD = -1.41, 95% CI (-2.34, -0.49), p = 0.003; Total bilirubin: SMD = -1.70, 95% CI (-3.36, -0.03), p = 0.05] but also had an excellent therapeutic effect on LF through four indexes [Hyaluronic acid: SMD = -1.15, 95% CI (-1.76, -0.53), p = 0.0003; Procollagen peptide III: SMD = -0.72, 95% CI (-1.29, -0.15), p = 0.01; Collagen IV: SMD = -0.69, 95% CI (-1.21, -0.18), p = 0.008; Laminin: SMD = -0.47, 95% CI (-0.95, 0.01), p = 0.06]. Concurrently, the liver stiffness measurement decreased significantly [SMD = -1.06, 95% CI (-1.77, -0.36), p = 0.003]. The results of network pharmacological experiments and molecular dynamics simulation indicate that the three high-frequency TCMs (Rhei Radix Et Rhizoma-Coptidis Rhizoma-Curcumae Longae Rhizoma, DH-HL-JH) primarily act on the core targets (AKT1, SRC, and JUN) via the core components (rhein, quercetin, stigmasterol, and curcumin), regulate the signal pathway (PI3K-Akt, MAPK, EGFR, and VEGF signaling pathways), and play a role of anti-LF. Conclusion: Meta-analysis indicates that TCM is beneficial in treating HLD patients and improving LF. The present study successfully predicts the effective components and potential targets and pathways involved in treating LF for the three high-frequency CHMs of DH-HL-JH. The findings of the present study are hoped to provide some evidence support for clinical treatment. Systematic review registration: https://www.crd.york.ac.uk/PROSPERO, identifier: CRD42022302374.

Atmospheric gaseous aromatic hydrocarbons in eastern China based on mobile measurements: Spatial distribution, secondary formation potential and source apportionment.

Monocyclic aromatic hydrocarbons (MAHs) and polycyclic aromatic hydrocarbons (PAHs) are both well known as hazardous air pollutants and also important anthropogenic precursors of tropospheric ozone (O3) and secondary organic aerosols (SOA). In recent years, there have been intensive studies covering MAHs emission from various sources and their behavior under stimulated photochemical conditions. Yet in-situ measurements of PAHs presence and variations in ambient air are sparse. Herein we conducted large geometrical scale mobile measurements for 16 aromatic hydrocarbons (AHs, including 7 MAHs and 9 PAHs) in eastern China between October 27 and November 8, 2019. This unique dataset has allowed for some insights in terms of AHs concentration variations, accompanying chemical composition, source contributions and spatial distributions in eastern China. In general, AHs showed a clear concentration variability between the south and the north of the Yangtze River Delta (YRD). The concentrations of PAHs were approximately 9% of AHs, but contributed 23% of SOA formation potential. Source apportionment via positive matrix factorization (PMF) model revealed that industrial processes as the largest source (44%) of observed AHs, followed by solvent usage (21%), vehicle exhaust (19%), coal combustion (11%) and coking processes (6%). In the perspective of PAHs sources, coal combustion emissions were identified as the dominating factor of a share of 41%-52% in eastern China. Our findings complemented the simultaneously monitoring information of PAHs and MAHs in eastern China, revealed the importance of PAHs to SOA formation and highlighted the necessity of formulating strategies to reduce emissions from anthropogenic sources and reduce risks to human health.

Observation-based sources evolution of non-methane hydrocarbons (NMHCs) in a megacity of China.

Both concentrations and emissions of many air pollutants have been decreasing due to implement of control measures in China, in contrast to the fact that an increase in emissions of non-methane hydrocarbons (NMHCs) has been reported. This study employed seven years continuous NMHCs measurements and the related activities data of Shanghai, a megacity in China, to explore evolution of emissions and effectiveness of air pollution control measures. The mixing ratio of NMHCs showed no statistical interannual changes, of which their compositions exhibited marked changes. This resulted in a decreasing trend of ozone formation potential by 3.8%/year (p < 0.05, the same below), which should be beneficial to ozone pollution mitigation as its production in Shanghai is in the NMHCs-limited regime. Observed alkanes, aromatics and acetylene changed by +3.7%/year, -5.9%/year and -7.4%/year, respectively, and alkenes showed no apparent trend. NMHCs sources were apportioned by a positive matrix factorization model. Accordingly, vehicular emissions (-5.9%/year) and petrochemical industry emissions (-7.1%/year) decreased significantly, but the decrease slowed down; significant reduction in solvent usage (-9.0%/year) appeared after 2010; however, emissions of natural gas (+12.6%/year) and fuel evaporation (with an increasing fraction) became more important. The inconsistency between observations and inventories was found in interannual trend and speciation as well as source contributions, emphasizing the need for further validation in NMHCs emission inventory. Our study confirms the effectiveness of measures targeting mobile and centralized emissions from industrial sources and reveals a need focusing on fugitive emissions, which provided new insights into future air policies in polluted region.

Anthropogenic monoterpenes aggravating ozone pollution.

Monoterpenes have been known to have a critical influence on air quality and climate change through their impact on the formation of fine particles. Here we present field evidence that monoterpene oxidations largely enhanced local ozone production in a regional site in eastern China. The observed monoterpene was most likely from biomass burning rather than biogenic emissions, as indicated by the high correlation with CO at night-time, and the observed ratio of these two species was consistent with previously determined values from biomass burning experiments. Fast monoterpene oxidations were determined experimentally based on direct radical measurements, leading to a daily ozone enhancement of 4-18 parts per billion by volume (ppb), which was 6%-16% of the total ozone production, depending on the speciation of monoterpenes. It demonstrates that the previously overlooked anthropogenic monoterpenes make an important contribution to O3 production in eastern China. The role could possibly be important at similar locations across China and other parts of the world that are characterized by massive emissions, especially where there are high NO x levels. Our results highlight that anthropogenic monoterpenes should be taken into account when proceeding with the coordinated mitigation of O3 and particulate matter pollution.

Evaluation of Mutton Quality Characteristics of Dongxiang Tribute Sheep Based on Membership Function and Gas Chromatography and Ion Mobility Spectrometry.

Dongxiang tribute sheep have a history of use in food dishes such as "Dongxiang Handgrip," which dates back hundreds of years and is a favorite halal food in northwestern China. However, little is known about the mutton quality characteristics of Dongxiang tribute sheep. Here, we measured the sensory characteristics, nutritional quality, and flavor substances to comprehensively evaluate the mutton quality characteristics of these sheep. The mutton qualities of Dongxiang tribute, Tibetan, Ujumqin, and Hu sheep were comprehensively evaluated by membership function. Subsequently, the volatile components in mutton samples from 30 Dongxiang tribute sheep were detected via gas chromatography and ion mobility spectrometry (GC-IMS), and their fingerprints were established. The result of meat quality revealed that the shear force, the contents of protein, essential amino acid (EAA), non-essential amino acid (NEAA), and n-6/n-3 ratio of Dongxiang tribute mutton were better than the other three breeds. Membership functions were calculated for 10 physical and chemical indexes of mutton quality, and the comprehensive membership function values of the four breeds in order of highest to lowest mutton quality were Tibetan sheep (0.76) > Dongxiang tribute sheep (0.49) > Hu sheep (0.46) > Ujumqin sheep (0.33). Thirty volatile compounds were identified via GC-IMS: seven alcohols, eight aldehydes, five ketones, two esters, two phenols, one ether, one furan, one acid, two hydrocarbons, and one pyrazine. Ketones, aldehydes, and alcohols were the main volatile compounds forming the flavor of Dongxiang tribute sheep mutton. The reliability of the results was validated by PCA (principal component analysis) and similarity analyses. Our results provide reference value for consumers of mutton in China.

Estimation of Aromatic Secondary Organic Aerosol Using a Molecular Tracer-A Chemical Transport Model Assessment.

A modified community multiscale air quality model, which can simulate the regional distributions of 2,3-dihydroxy-4-oxopentanoic acid (DHOPA), a marker species for monoaromatic secondary organic aerosol (SOA), was applied to assess the applicability of using the DHOPA to aromatic SOA mass ratio (fSOA) from smog chamber experiments to estimate aromatic SOA during a three-week wintertime air quality campaign in urban Shanghai. The modeled daily DHOPA concentrations based on the chamber-derived mass yields agree well with the organic marker field measurements (R = 0.79; MFB = 0.152; and MFE = 0.440). Two-thirds of the DHOPA are from the oxidation of ARO1 (lumped less-reactive aromatic species; mostly toluene), with the rest from ARO2 (lumped more-reactive aromatic species; mostly xylenes). Modeled DHOPA is mainly in the particle phase under ambient organic aerosol (OA) loading but could exhibit significant gas-particle partitioning when a higher estimation of the DHOPA vapor pressure is used. The modeled fSOA shows a strong dependence on the OA loading when only semivolatile aromatic SOA components are included in the fSOA calculations. However, this OA dependence becomes weaker when non-volatile oligomers and dicarbonyl SOA products are considered. A constant fSOA value of ∼0.002 is determined when all aromatic SOA components are included, which is a factor of 2 smaller than the commonly applied chamber-based fSOA value of 0.004 for toluene. This model-derived fSOA value does not show much spatial variation and is not sensitive to alternative estimates of DHOPA vapor pressures and SOA yields, and thus provides an appropriate scaling factor to assess aromatic SOA from DHOPA measurements. This result helps refine the quantification of SOA attributable to monoaromatic hydrocarbons in urban environments and thereby facilitates the evaluation of control measures targeting these specific precursors.

[Characterization of Volatile Organic Compounds (VOCs) Using Mobile Monitoring Around the Industrial Parks in the Yangzte River Delta Region of China].

Volatile organic compounds (VOCs) play important roles in the formation of ozone and fine particles in the troposphere. Industrial parks emit significant amounts of VOCs in China, while few studies have characterized them. In the present study, a mobile platform was employed to measure the levels and composition VOCs around industrial parks in the Yangzte River Delta region. The average concentration of VOCs ranged from 39 µg·m-3 (5% percentile) to 533 µg·m-3 (95% percentile) with an average of 183 µg·m-3, which was three times that of ambient concentrations. Maximum VOC concentrations ranged from 307 µg·m-3 (5% percentile) to 12006 µg·m-3 (95% percentile) with an average of 2812 µg·m-3. The frequency of abnormal peak values was as high as 64% across all the industrial parks, of which toluene (32%), xylene (18%), benzene (9%), and>C9 aromatics (19%) were the most common species. Differences in VOC characteristics were observed among the different types of industrial parks. Specifically, highest concentrations of VOCs were observed in textile industrial parks followed by chemical, painting, and petrochemical industrial parks, and VOC concentrations in electronics industrial parks were the lowest. Importantly, species measured using the mobile platform only contributed~50% of VOCs present in ambient samples, indicating that the concentrations of VOCs in the industrial parks were underestimated overall. These results can inform measures to control VOC pollution in industrial parks in China.

Simultaneous observation of atmospheric peroxyacetyl nitrate and ozone in the megacity of Shanghai, China: Regional transport and thermal decomposition.

Atmospheric peroxyacetyl nitrate (PAN) and ozone (O3) are two typical indicators for photochemical pollution that have adverse effects on the ecosystem and human health. Observation networks for these pollutants have been expanding in developed regions of China, such as North China Plain (NCP) and Pearl River Delta (PRD), but are sparse in Yangtze River Delta (YRD), meaning their concentration and influencing factors remain poorly understood. Here, we performed a one-year measurement of atmospheric PAN, O3, particulate matter with aerodynamic diameter smaller than 2.5 µm (PM2.5), nitrogen oxides (NOx), carbon monoxide (CO), and meteorological parameters from December 2016 to November 2017 in Shanghai. Overall, high hourly maximum PAN and O3 were found to be 7.0 and 185 ppbv in summer, 6.2 and 146 ppbv in autumn, 5.8 and 137 ppbv in spring, and 6.0 and 76.7 ppbv in winter, respectively. Continental air masses probably carried atmospheric pollutants to the sampling site, while frequent maritime winds brought in less polluted air masses. Furthermore, positive correlations (R: 0.72-0.85) between PAN and O3 were found in summer, indicating a predominant role of photochemistry in their formation. Unlike in summer, weak or no correlations between PAN and O3 were featured during the other seasons, especially in winter, due to their different loss pathways. Unexpectedly, positive correlations between PAN and PM2.5 were found in all seasons. During summer, moderate correlation could be attributed to the strong photochemistry acting as a common driver in the formation of secondary aerosols and PAN. During winter, high PM2.5 might promote PAN production through HONO production, hence resulting in a good positive correlation. Additionally, the loss of PAN by thermal decomposition (TPAN) only accounted for a small fraction (ca. 1%) of the total (PAN + TPAN) during a typical winter episode, while it significantly reached 14.4 ppbv (71.1% of the total) in summer.

Analysis of volatile compounds and flavor fingerprint in Jingyuan lamb of different ages using gas chromatography-ion mobility spectrometry (GC-IMS).

In this study, gas chromatography coupled to an ion mobility spectrometry (GC-IMS) was used for analyzing some volatile components and flavor fingerprint in samples from Jingyuan lambs of different ages (2, 6, and 12 months). The data obtained from ion mobility were processed using laboratory analysis view processing software for fingerprint recognition, and the principal component analysis (PCA) was performed. GC-IMS provided information on the characteristics and strength of 66 volatile flavor compounds (monomers and dimers). The differences in flavoring substances between lambs of different ages were observed. The compounds with higher intensity peaks in the lamb meat samples were alcohols (1-octen-3-ol, ethanol, (E)-2-hexen-1-ol, 1-pentanol, and 2-propanol), ketones (2-pentanone, 2-heptanone, 3-hydroxy-2-butanone, 2-hexanone, 2-butanone, 2-propanone, and 4-methyl-2-pentanone), aldehydes (n-nonanal, octanal, heptanal, 3-methylbutanal, hexanal, pentanal, 2-methylbutanal, (E)-2-octenal, (E)-2-nonenal, methional, and phenylacetaldehyde), esters (methyl benzoate), furan (2-pentylfuran), and thiazole (trimethylthiazole). The results showed that the flavor fingerprint in samples from Jingyuan lambs of different ages (2, 6, and 12 months) can be established by GC-IMS and PCA based on the identified volatile compounds. This method might be used for the rapid and comprehensive analysis of volatile components in lamb meat.

An psychoeducation programme based on self-efficacy theory to improve experience of natural birth for primigravid women: Study protocol for a randomised controlled trial.

AIM AND OBJECTIVES: To present a study protocol for estimating the feasibility, effectiveness and safety of an individual (five sessions), group (one session) and face-to-face psychoeducation programme based on self-efficacy theory to improve childbirth experience of primigravid women. BACKGROUND: In present China, fertility rates are falling and ageing is accelerating. How to improve the fertility level of childbearing women is of great significance. However, about 10%-20% of women have negative childbirth experience after birth, which seriously affects maternal and child health and family functions, and even fertility desires and intentions in the future. Nevertheless, due to the lack of a series of well-designed randomised controlled trials(RCTs), there is no specific methodology to guide the most effective intervention for primigravid women. In this regard, based on Bandura's self-efficacy theory, an intervention programme to promote a positive childbirth experience for primigravid women has been designed and will be evaluated to determine its impact on primigravid women. DESIGN: A non-blinded randomised controlled trial. METHODS: We report the study protocol for this randomised controlled trial based on the SPIRIT2013 statement. A total of 238 eligible primigravid women will be randomly divided into the control group (n = 119) or the intervention group (n = 119). The control group will receive care as usual, that is, six routine prenatal examinations. In addition to the routine examinations, the intervention group will also receive six face-to-face interventions. Baseline assessment will occur at about 24th week of gestation and follow up at 37th weeks of gestation, intrapartum, 1-3 days postpartum and 42 days postpartum. The primary outcomes are childbirth experience, childbirth self-efficacy; others are fear of childbirth, labour control, labour pain and labour satisfaction. IMPACT: From the perspective of clinical work, this protocol provides practical guidance for cultivating the positive childbirth experience of the primigravid women. From the perspective of sociology, the positive experience and emotion of primigravid women can improve the fertility intention of women of childbearing age, which is relatively conducive to optimising Chinese demographic structure and reducing the pressure of ageing population in the long term.

Transcriptome-metabolome analysis of fatty acid of Bamei pork and Gansu Black pork in China.

To study the difference in transcriptome level of fatty acid metabolism pathway in Bamei pork and the difference of pork quality caused by the difference. In this study, Bamei pigs breeding in Huzhu farm of QingHai province were selected as the test object, compared with Gansu Black pigs. Four indexes of nutmeg acid (DX1), palmitic acid (DX2), stearic acid (DX3) and linoleic acid (DX4) were set. The expression profiles of fat metabolism related genes between the two groups samples were analysed by GCMS metabolomics and transcriptomics, then coexpression network analysis were conducted to obtain phenotypic related genes. The results showed that the metabolic levels of DX3 and DX4 were significantly higher than those of other fatty acids. Among these differences, the ENSSSCG00000024681 (G1) and ENSSSCG00000036883 (G2) genes play important regulatory roles in fatty acid metabolism, and the upregulated expression of their gene obviously affects the level of fatty acid metabolism, thereby affecting the quality and taste of pork. In addition, we found that there was a good correlation between the same lines, and the genetic traits of the hybrid lines of Bamei pig and Black pig are more inclined to Bamei pig. In the independent fatty acid metabolism, "Mg2+"and flavin adenine dinucleotide are more active, which plays an important role in energy utilization. Therefore, we can be inferred that the metabolism of stearic acid and linoleic acid are important fatty acids for pork quality. It also further confirms that the research method of combined omics is of great significance for the study of species traits and gene functions.

The role of workplace social capital on the relationship between perceived stress and professional identity among clinical nurses during the COVID-19 outbreak.

AIM: Workplace social capital refers to relationship networks formed by individuals in an organization through long-term mutually beneficial interactions and cooperation with members. These relationship networks can create value and resources for organizations and individuals. This current study aimed to explore the potential impact of workplace social capital on the association between perceived stress and professional identity in clinical nurses during the COVID-19 outbreak. METHODS: In this cross-sectional study, 308 Chinese clinical nurses filled out the Chinese Workplace Social Capital Scale, the Chinese Perceived Stress Scale, and the Chinese Nurse's Professional Identity Scale. Descriptive analysis, independent samples t test, analysis of variance, Pearson correlation analyses, and bootstrap method were performed to analyze the data. RESULTS: Perceived stress was negatively correlated with professional identity (r = -0.455, p < .001). Workplace social capital was not found to moderate the relationship between perceived stress and professional identity (95% CI -0.03 to- 0.06, p = .47 > .05). Instead, it mediated that relationship (95% CI -0.61 to -0.19, p < .05), and its mediating effect was -0.37. CONCLUSIONS: In the early stages of the COVID-19 outbreak, workplace social capital among the investigated clinical nurses failed to buffer the negative impact of perceived stress on professional identity, but it did play a part in mediating perceived stress and professional identity. A healthy workplace should be provided to clinical nurses to improve their professional identity, while lowering perceived stress.

[Characteristics and Reactivity of Ambient VOCs in Urban Hangzhou, China].

The ambient concentration of 122 volatile organic compound (VOC) species were continuously measured in urban Hangzhou, China from May 2018 to April 2019. The average mixing ratio of VOCs was (59.4±23.6)×10-9 and the oxygenated VOCs (OVOC) were the largest component. There was no clear "weekend effect" in urban Hangzhou, while the concentration of VOCs had a sharp decrease during long holidays. The concentration of VOCs had a positive correlation with air quality index (AQI) and reached the highest level when the primary pollutant was PM2.5. The assessment results of atmospheric chemical reactivity with·OH radical loss rate (L·OH) and ozone formation potential (OFP) showed the average value of L·OH was 7.5 s-1 and that of OFP was 152.1×10-9, among which carbonyl compounds, aromatics, and alkenes were the most abundant components. The overall chemical reactivity level of VOCs in Hangzhou was equivalent to 2-methylpentane. The average value of toluene/benzene (T/B) was 1.95, which implied the ambient VOCs in Hangzhou were influenced by vehicle exhaust. Secondary formation (17.6%), combustion (11.8%), industrial processing (12.3%), solvent use (18.1%), biogenic source (4.5%), and vehicle exhaust (35.7%) were identified as six major sources of VOCs in Hangzhou through the positive matrix factorization (PMF) model.

[Characteristics and Reactivity of VOCs in Hangzhou During a Typical Photochemical Pollution Episode].

An intensive observation of ambient volatile organic compounds (VOCs) was carried out in Hangzhou, a key city in the Yangtze River Delta, during a typical photochemical pollution episode from September 14-23, 2018. The analysis results of 80 effective samples showed that the average concentration of 122 compounds of VOCs was (59.5±19.8)×10-9 during the observation period, and oxygenated VOCs (OVOCs) were the most abundant component. The assessment results of atmospheric reaction activity with ozone formation potential (OFP) showed that the average value of OFP was 145×10-9 during the observation period, of which alkenes and carbonyl compounds were the most abundant components. The chemical reactivity of VOCs in Hangzhou was equivalent to acrylonitrile. Based on the positive matrix factorization (PMF) model, five major sources of VOCs in Hangzhou were identified, including secondary formation (25.2%), combustion and industrial processing (27.2%), solvent use (17.3%), biogenic sources (9.2%), and vehicular exhaust (21.2%). The results can provide guidance for further understanding of VOC characteristics and the basis for scientific prevention and control measures in Hangzhou.

Assessing the Effect of Reactive Oxygen Species and Volatile Organic Compound Profiles Coming from Certain Types of Chinese Cooking on the Toxicity of Human Bronchial Epithelial Cells.

The International Agency of Research on Cancer identifies high-temperature frying, which features prominently in Chinese cooking, as producing group 2A carcinogens. This study simultaneously characterized particulate and gaseous-phase cooking emissions, monitored their reactive oxygen species (ROS) concentrations, and evaluated their impact on genetic damage and expression in exposed human bronchial epithelial cells. Five types of edible oil, three kinds of seasonings, and two dishes were assessed. Among tested edible oils, heating of soybean oil released the largest particle number concentration (2.09 × 1013 particles/(g cooking material and oil)·h) and volatile organic compounds (VOCs) emissions (12103.42 µg/(g cooking material and oil)·h). Heating of lard produced the greatest particle mass concentration (0.75 mg/(g cooking material and oil)·h). The main finding was that sunflower and rapeseed oils produced the highest ROS concentrations (80.48 and 71.75 nmol/(g cooking material and oil)·h, respectively). ROS formation most likely occurred during the autoxidation of both polyunsaturated and monounsaturated fatty acids. Among all the tested parameters, only ROS concentrations exhibited consistency with cell viability and showed significant correlations with the expression levels of CYP1A1, HIF-1a, and especially with IL-8 (the marker for oxidative stress within the cell). These findings indicate that ROS concentration is potentially a suitable metric for direct assessment of exposure levels and potential toxicity.

Estimating Secondary Organic Aerosol Production from Toluene Photochemistry in a Megacity of China.

The production of secondary organic aerosols (SOA) from toluene photochemistry in Shanghai, a megacity of China, was estimated by two approaches, the parametrization method and the tracer-based method. The temporal profiles of toluene, together with other fifty-six volatile organic compounds (VOCs), were characterized. Combing with the vapor wall loss corrected SOA yields derived from chamber experiments, the estimated toluene SOA by the parametrization method as embodied in the two-product model contributes up to ∼40% of the total SOA budget during summertime. 2,3-Dihydroxy-4-oxopentanoic acid (DHOPA), a unique product from the OH-initiated oxidation of toluene in the presence of elevated NOx, was used as a tracer to back calculate the toluene SOA concentrations. By taking account for the effect of gas-particle partitioning processes on the fraction of DHOPA in the particle phase, the estimated toluene SOA concentrations agree within ∼33% with the estimates by the parametrization method. The agreement between these two independent approaches highlight the need to update current model frameworks with recent laboratory advances for a more accurate representation of SOA formation in regions with substantial anthropogenic emissions.