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Objectives: Outstanding physical-mechanical properties and aging resistance are key requirements for dental resin composite since it will be placed in the oral environment for a long time. In this work, a new dental resin composite mainly modified by glass flakes was fabricated, and the aging resistance was evaluated by comparing with commercial composites without glass flakes. Materials and methods: The new dental resin composite was produced through hand blending of inorganic glass flakes/Si-Al-borosilicate glass (58wt%:7wt% of dental resin composite), POSS-MA (5wt% of resin matrix), Bis-GMA/TEGDMA(64.4wt%:27.6wt% of resin matrix), and CQ/EDMAB (0.9wt%:2.1wt% of resin matrix) together. The flexural strength, elasticity modulus, and hardness, as well as wear were tested for evaluating the aging resistance of different dental resin composite. Results: Among 6 kinds of commercial composites in this study, after 6-month water storage, the maximum percentage of performance degradation is that the flexural strength decreased 39.96%, elasticity modulus decreased 51.53% and hardness decreased 12.52%. In contrast, the new synthesized material decreased 14.53%, 20.88%, and 0.61%, respectively, and performed lesser wear depth compared to some other groups (P < 0.05). Conclusions: It was observed that the new dental resin composite performed better performance stability and wear resistance when compared with commercial dimethacrylate-based or low shrinkage dental resin composite tested in this study. Clinical relevance: This possibly paves a path for designing tailored dental composite for practical application. Since the aging resistance of dental resin composite modified by glass flakes is superior, it has the potential to be used for promoting the durability of dental resin composite. [ABSTRACT FROM AUTHOR]

Short- and medium-chain chlorinated paraffins (SCCPs and MCCPs) are hazardous industrial chemicals that tend to bioaccumulate in animal-derived foodstuffs through the food supply chain. However, the lack of reliable noninvasive bioindicators hinders the monitoring of farm animal exposure to CPs. In this study, 169 cattle hair samples were collected from beef cattle farms in six Chinese provinces, with further beef, feed, and soil samples being collected in Hebei province. Geographical differences in CP concentrations were observed in the hair samples, and CP concentrations in samples collected from Hebei province decreased in the following order: hair > feed > beef > soil. C 10–11 Cl 6–7 and C 14 Cl 7–8 were the predominant SCCPs and MCCPs, respectively, in all the hair, beef, feed, and soil samples. CP concentrations in hair samples significantly correlated with those in beef, feed, and soil samples, indicating that hair can be used as a bioindicator of cattle exposure to CPs. The possible health risks associated with exposure to CPs through beef consumption, especially for children and high-volume beef consumers, should be further investigated. [Display omitted] • The chlorinated paraffin (CP) contents of cattle hair samples varied geographically. • Higher CP levels were found in hair than in beef, feed, or soil from the same region. • The CP contents of beef, feed, hair, and soil samples correlated significantly. • Hair serves as a noninvasive bioindicator of beef cattle exposure to CPs. • Certain population groups are at risk of CP exposure through beef consumption. [ABSTRACT FROM AUTHOR]

Chlorinated paraffins (CPs) in poultry feed and the farm environment might bioaccumulate in poultry eggs. Unlike chickens, which are mostly raised in cages, ducks are commonly raised free range. This would expose ducks to CPs in the environment. However, information on the presence of CPs on duck farms is scarce. In the present study, samples of duck eggs, duck feathers, poultry feed, and soil were collected from 25 duck farms in South China. Forty-eight congener groups of short- and medium-chain CPs (SCCPs and MCCPs) were detected in the samples. Interestingly, relatively high concentrations of SCCPs and MCCPs were found in the duck feathers. The median concentrations of SCCPs and MCCPs in the duck eggs, feathers, feed and soil were: 46 and 18 ng/g wet weight, 2460 and 992 ng/g, 103 and 47 ng/g, and 24 and 10 ng/g dry weight, respectively. The dominant groups of SCCPs and MCCPs were C 10 Cl 6–7 and C 14 Cl 7–8 , respectively. The close relationship between duck feathers and poultry feed indicated that the duck feathers might act as a bioindicator for the exposure of ducks to CPs. The margin of exposure approach was used to assess the health risk, with the results showing that the consumption of duck eggs posed a low risk to different age groups from exposure to SCCPs and MCCPs. [Display omitted] • Higher concentrations of CPs were found in duck feathers than eggs, feed and soil. • The dominant CPs had short carbon chains and low levels of chlorine. • There was a close relationship between CPs in the feathers and feed. • The human exposure risk to CPs through duck egg consumption was low. [ABSTRACT FROM AUTHOR]

The presence of polychlorinated biphenyls (PCBs) in feed materials has caused great public concern because PCBs can accumulate in farmed animals, be transferred farm-to-fork and, ultimately, have a detrimental impact on human health. Recently, the occurrence of PCBs in marine environments has garnered scientific attention due to their high levels and potential reproductive threats to marine apex predators. Fishmeal is marine-origin feed material and is susceptible to PCB contamination from the aquatic trophic chain. The present study collected 102 fishmeal samples during 2012–2017 from major global fishmeal production areas (United States, Europe, China, South America and Southeast Asia). The levels of PCBs (26 congeners) were between 0.4 and 19.9 ng g−1 dw (mean: 1.94 ng g−1 dw), with a 75.3% contribution from indicator PCBs on a weight basis. Together with PCDD/Fs, 4.9% of fishmeal exceeded the maximum levels set by the European Commission for dioxin-like compounds (4.0 pg WHO-TEQ/g). The highest PCB levels were found in fishmeal from the U.S. (6.85 ng g−1 dw), which was nearly five times higher than the other four sampling areas. No clear time trends were found for PCBs in fishmeal during the sampling period. Predicted PCB concentrations in farmed fish via fishmeal consumption were between 1.24 and 2.76 ng g−1 dw, which was comparable to PCBs in market fish. When compared to other emerging POPs in the same batches of fishmeal, PCBs were still found to be an alarming class of POPs. Some PCB and PBDE congeners might have similar sources and environmental behaviors. Image 1 • The occurrence and profile of PCBs were identified in global fishmeal. • Fishmeal from the U.S. presented the highest PCB levels of five studied regions. • PCBs are still significant POPs despite having leveled off in marine environments. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Fishmeal is employed to evaluate PFAA levels on a global scale. • PFOS predominated, and a pervasive occurrence of short-chain PFAAs were found in fishmeal. • Fishmeal PFAAs were weighted more in industrialized areas compared to less industrialized areas. • Coastal residents are at risk of PFOS exposure through the farm-to-fork pathway. Abstract Few studies have attempted to elucidate the occurrence of perfluoroalkyl acids (PFAAs) in animal feeds and how they play a role in human ingestion. Fishmeal was the most important animal-derived feed in global husbandry and may have been subjected to PFAA contamination considering the PFAAs' ubiquitous distribution in aquatic ecosystems. We collected ninety-two commercial fishmeal from the most important fishmeal-producing countries and found that Σ 16 PFAAs ranged from 0.65 to 85.5 ng/g (average: 18.2 ng/g, 12% moisture). PFOS still predominated, with unexpected high detection of PFUnDA. The wide occurrence of short-chain PFAAs (e.g., PFBA, PFBS) in fishmeal were found for the first time. From a geographical view, PFAA levels in fishmeal that originated from the Northern Hemisphere were significantly higher than those from the Southern Hemisphere (p < 0.01). Higher levels of under-studied long-chain PFAAs (PFNA, PFDA, PFUnDA, PFDoDA and PFTrDA) weighted more in industrialized areas than less industrialized areas, whereas the legacy PFAAs (PFOS, PFOA and PFHxS) were comparable among all regions. The estimated daily intake was calculated from animal feed to humans (via cultured fish) from 20 Chinese provinces by the Monte Carlo Simulation. A proportion of 29.8% of residents from the Fujian Province exceeded the EFSA's suggestion for PFOS ingestion. [ABSTRACT FROM AUTHOR]

Highlights • The formation of PCNs during the heating of sucralose was investigated. • Factors affecting PCN formation and distribution were determined. • Naphthalene chlorination might be an important pathway for PCN formation. [ABSTRACT FROM AUTHOR]

Abstract Chlorinated paraffins (CPs) are ubiquitous environmental pollutants that are lipophilic and can accumulate in the food chain. Animal-derived products are predominant contributors to human CP exposure. CPs in animal feed might accumulate in domestic animals through dietary exposure, leading to potential contamination of animal-derived food products and human health risks. However, information on the presence of CPs in animal feed materials is scarce. In this study, 16 animal feed material samples were collected in China in 2016. Thirteen of the samples were of animal origin and three were of plant origin. The concentrations and carbon and chlorine congener group profiles of shortchain chlorinated paraffins (SCCPs) and medium-chain chlorinated paraffins (MCCPs) in these animal feed materials were investigated. The concentrations of SCCPs were higher than those of MCCPs in all of the samples. The SCCP concentration range was 120 to 1700 ng/g (mean 640 ng/g), and the MCCP concentration range was 6.4 to 260 ng/g (mean 78 ng/g). Fish meal had the highest SCCP and MCCP concentrations. The lowest SCCP and MCCP concentrations were detected in peanut meal and whey powder, respectively. The concentrations of SCCPs and MCCPs varied among the types of animal feed materials. SCCP and MCCP concentrations also varied among samples of the same type of animal feed material. Relatively high concentrations of SCCPs and MCCPs were detected in feed materials of animal origin. The predominant congener groups in the animal feed materials were C10-11Cl6-7 for SCCPs and C14Cl7 for MCCPs. The carbon and chlorine congener group profiles of SCCPs indicated that SCCP contamination in the animal feed materials might arise from commercial CP mixtures. Graphical abstract Unlabelled Image Highlights • CP concentrations were determined in animal feed materials. • SCCP concentrations were higher than those of MCCPs in each animal feed material. • CP levels in animal-based feed material were higher than in plant-based material. • Estimated concentrations of SCCPs and MCCPs in farmed fish were calculated. [ABSTRACT FROM AUTHOR]

Abstract Concentrations and patterns of 75 PCN congeners in feed raw materials of animal and plant origin were investigated. Six types of feed raw materials of animal origin and three types of feed raw materials of plant origin from China were collected in 2016. The total concentrations of PCNs in the collected materials ranged from 147 to 1009 ng kg-1, with the highest occurring in fish meal. The mean PCNs concentration in feed raw materials of animal origin (551 ng kg-1) was higher than in those of plant origin (294 ng kg-1). Additionally, lower chlorinated PCNs were the main homologues in raw feed materials, while Di-CNs were the predominant homologues in all samples (mean: 53%), followed by tri-CNs (mean: 28%). The most abundant congeners were CN5/7 and 24/14. Additionally, the toxicity equivalencies (TEQs) of PCNs in the feed raw materials ranged from 0.010 to 0.046 ng TEQ kg-1, with the highest TEQ concentrations of PCNs detected in gluten meal. Together, CN5/7, 66/67, 65/70, and 73 contributed approximately 64% of the total PCN TEQs in raw feed materials. Concentrations of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and polychlorinated biphenyls (PCBs) in the feed raw materials were detected to compare the TEQ distribution of those dioxin-like compounds. The mass concentrations of PCNs were 1–3 orders of magnitude higher than those of PCDD, PCDFs and PCBs, while the TEQ concentrations of PCNs contributed 2.0%–6.5% of the total TEQs of PCNs, PCDDs, PCDFs and PCBs in the feed raw materials. Highlights • Concentrations of 75 PCN congeners were determined in feed raw materials. • Relatively high PCN concentrations were found in fish meal. • PCN TEQs were lower than those of PCDDs, PCDFs or PCBs in the same samples. • Potential sources for PCNs in feed raw materials were discussed. [ABSTRACT FROM AUTHOR]

Abstract: Antibacterial materials are recognized as important biomaterials due to their effective inhibition of bacterial infections. Hydrogels are 3D polymer networks crosslinked by either physical interactions or covalent bonds. Currently, hydrogels with an antibacterial function are a main focus in biomedical research. Many advanced antibacterial hydrogels are developed, each possessing unique qualities, namely high water swellability, high oxygen permeability, improved biocompatibility, ease of loading and releasing drugs, and structural diversity. Here, an overview of the structures, performances, mechanisms of action, loading and release behaviors, and applications of various antibacterial hydrogel formulations is provided. Furthermore, the prospects in biomedical research and clinical applications are predicted. [ABSTRACT FROM AUTHOR]

ι-Carrageenan is an algal polysaccharide widely applied in the food industry. Specific glycoside hydrolases are valuable tools for modifying polysaccharides and producing oligosaccharides. In this study, the gene of a novel GH82 family ι-carrageenase was cloned from the genome of marine bacterium Wenyingzhuangia fucanilytica . The ι-carrageenase designated as Cgi82A was expressed in Escherichia coli , and its biochemical properties, kinetic constants and hydrolysis pattern were characterized. The enzyme could reach its highest activity at 25 °C, which is lower than all hitherto reported GH82 ι-carrageenases. It was an endo-acting hydrolase, and could be utilized as a potential biocatalyst for producing ι-carrageenan oligosaccharides with different polymerization degrees. Cgi82A possessed relatively high substrate-binding affinity and catalysis efficiency indicated by its kinetic constants ( K m , 1.12 μM; K cat , 560.75 s −1 ). Its major end product was ι-carrageenan tetrasaccharide. The acquiring of this novel enzyme would facilitate the future application of ι-carrageenan and its oligosaccharides. [ABSTRACT FROM AUTHOR]

α- l -Fucosyl residues are frequently found in oligosaccharides, polysaccharides and glycoconjugates which play fundamental roles in various biological processes. α- l -Fucosidases, glycoside hydrolases for catalyzing the removal of α- l -fucose, can serve as desirable tools in the study and the modification of fucose-containing biomolecules. In this study, an α- l -fucosidase named as Alf1_Wf was purified from a marine bacterium Wenyingzhuangia fucanilytica by using a combination of chromatographic procedures. The sequence of Alf1_Wf was identified via proteomics analysis against the predicted proteome of the bacterium. Recombinant Alf1_Wf with 6×His tag was expressed in E. coli and showed α- l -fucosidase activity. Sequence annotation revealed that Alf1_Wf contained a combination of GH29 catalytic domain and CBM35 accessory domain. Alf1_Wf was confirmed as a member of GH29-A subfamily based on the phylogenetic analysis. Furthermore, biochemical properties and kinetic characteristics of the enzyme were also determined. Substrate specificity determination showed that Alf1_Wf was capable in hydrolyzing α1,4-fucosidic linkage and synthetic substrate pNP-fucose. Besides, Alf1_Wf could act on partially degraded fucoidan. This study successfully purified, identified, cloned, expressed and characterized a novel α- l -fucosidase, and meanwhile revealed a new multidomain structure of glycoside hydrolase. The knowledge gained from this study should facilitate the further research and application of α- l -fucosidases. [ABSTRACT FROM AUTHOR]

Animal derived foods are the primary pathway for human exposure to polychlorinated naphthalenes (PCNs), and various foodstuffs have been reported to contain PCNs. However, information on how PCN emission sources affect surrounding animal farms is scarce. The present study determined PCN levels in cow's milk, excrement, feed, plant and soil samples collected from four dairy farms situated within 10 km of an iron smelting plant in China. PCN concentrations in the milk samples from all four farms were in the range from 470 to 797 pg/g lipid weight while the PCN concentrations in the other specimens decreased in the order: plant > soil > excrement > feed. Higher PCN concentrations appeared in silage than in other feedstuffs, and the relationships between PCNs in milk, excrement and feed were closer than those in plant and soil. Human exposure risk to PCNs by consuming milk from this region was relatively higher than in less polluted areas. • PCN concentrations in plants and soil were higher than in excrement and feed. • Similar PCN patterns were found in milk, excrement and feed. • PCNs in silage showed higher concentrations than in other feedstuffs. • Tri- and di-CNs were the predominant homologues in all samples. • Relatively high risk posed to humans by PCNs in milk from this region. [ABSTRACT FROM AUTHOR]

3D ordered silver nanoshells silica photonic crystal beads as a novel encoded surface enhanced Raman scattering substrate are proposed for the development of highly efficient multiplex bioassays. [ABSTRACT FROM AUTHOR]

• A total of 75 PCN congeners in raw cow milk from China were determined. • PCN concentrations in cow milk could be influenced by PCN emission sources. • PCNs in cow milk were dominated by lower chlorinated congeners. • Silage acted as an important carrier for the migration of PCNs into cow milk. • Chinese exposure risk to PCNs through the intake of cow milk is not significant. The potential contamination of food items with polychlorinated naphthalenes (PCNs) has attracted increasing attention because of their toxicity, persistence and bioaccumulative characteristics. Humans are exposed to PCNs primarily through consuming animal-derived foodstuffs. However, the pathways by which PCNs can enter the food supplying chain are poorly understood. In this study, Σ 75 PCNs were determined in raw cow milk (n = 82) collected from three different regions that varied in the intensity of PCNs emission sources in North China, using high-resolution gas chromatography/high-resolution mass spectrometry method. Higher PCN concentrations (214–2050 pg/g lw) were found in raw cow milk from dairy cow farms located in the region with relatively higher intensity of emission sources. Less chlorinated congeners were dominant in all raw cow milk samples. PCNs in cow milk might result from industrial fly ash emissions that contaminate animal feed through atmospheric deposition. Risks posed to humans through consuming PCNs in cow milk were low. [ABSTRACT FROM AUTHOR]

Abstract: Sucralose, an artificial sweetener, is being used in increasingly large amounts in foodstuffs and beverages worldwide. Information pertaining to its ability to participate in chlorination reactions during cooking and generate toxic compounds, however, is scarce. In this study, the formation and distribution of polychlorinated naphthalenes (PCNs), which are a group of highly toxic polychlorinated aromatic compounds, in oil heated in the presence of sucralose was investigated. The concentrations of the PCNs present in the cooking oils and oil fumes generated during the heating process were determined by isotope dilution according to a HRGC/HRMS method. The results suggested that the heating of cooking oil in the presence of sucralose promoted the formation of toxic PCNs. Although PCNs were detected in the oil fumes, no PCNs were found in the heated oils. The total concentrations of the PCNs found in peanut and olive oil fumes were 490 and 240 pg g−1, respectively. The degree of chlorination for the PCNs was calculated to be 5.3 for both the peanut and olive oil fumes. To quantify the newly produced PCNs, sucralose used in the experiments were about 2 or 3 orders of magnitude higher than in reality. PCNs were not detected with real proportions under the current experimental conditions. [Copyright &y& Elsevier]

Abstract: The formation and distribution of dioxin-like polychlorinated biphenyls (dl-PCBs) during cooking was investigated. Concentrations of dl-PCBs in liquid residues, cooked beef, and oil fumes generated during heating were determined by isotope dilution HRGC/HRMS. Although the levels of dl-PCBs in well-done beef were lower compared with those of raw beef, relatively high concentrations of dl-PCBs were detected in the oil fumes produced during heating. This suggests that dl-PCBs in raw beef may have volatilized into the oil fumes during the cooking process. Sucralose and chloropropanols contained in raw materials may have resulted in increased dl-PCB concentrations and the level of toxic equivalents (TEQ) in the oil fumes produced under high temperature during cooking. Concentrations of dl-PCBs did not vary greatly in cooked beef, except when higher levels of chloropropanols were presented in the uncooked raw materials. Results indicate that sucralose and chloropropanols may promote the formation of dl-PCBs during the cooking process. The newly produced dl-PCBs from raw beef cooking were mainly present in oil fumes, which gave rise to high levels of TEQ in oil fumes. [Copyright &y& Elsevier]

• A UPLC-MS/MS method was developed for the determination of 12 bisphenols in animal feed. • The post-column ammonium hydroxide infusion was employed to improve sensitivities over 1.6–8.2 times. • Each investigated feed sample was simultaneously contaminated with at least 2 to 4 bisphenols. • BPA was the dominant analogue of BPs found in animal feed samples with concentrations ranging from 0.92 to 7.77 ng g−1. Bisphenol compounds (BPs) are a group of environmental contaminants with endocrine-disrupting effects both for humans and animals. The present work developed a sensitive analytical method for the detection of multiple BPs in the animal feed based on ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) with post-column ammonium hydroxide (NH 4 OH) infusion. A modified QuEChERS method was incorporated into the extraction and purification processes. The limit of detection (LODs) and quantification (LOQs) for the target BPs were in the ranges of 0.02–0.75 μg kg−1 and 0.04–0.95 μg kg−1, respectively. Average recoveries were ranged between 82.6% and 112%. The proposed method was successfully applied to determine the concentrations of BPs in 20 actual feed samples, and the preliminary profiles of BPs in products from local feed factories were obtained. Each sample was simultaneously contaminated with at least 2 to 4 BPs, and bisphenol A (BPA) was the dominant analog of BPs found in animal feed. [ABSTRACT FROM AUTHOR]

Aquatic foods are important sources of chlorinated paraffins (CPs) to humans. Farmed crabs are bottom-dwelling aquatic animals, and can accumulate CPs through food and aquatic environment. However, limited information is available on CPs concentrations in and sources to farmed crabs. In this study, short-chain CPs (SCCPs) and medium-chain CPs (MCCPs) concentrations in 59 samples from the farmed crab food web (crab, crab feed, and aquaculture environment) were determined. The samples were from 17 crab farms in Anhui Province, Jiangxi Province, and Shanghai, in China. The SCCPs and MCCPs concentrations in the crab samples were 82–1760 and not detected–680 ng/g lipid weight, respectively. The dominant SCCPs and MCCPs in the crab samples were C 10 Cl 6−7 and C 14 Cl 7−8 , respectively. The SCCPs concentrations in the crab food web samples were higher than the MCCPs concentrations. SCCPs contamination of the crab food web samples was not directly related to CPs product use. The main factors affecting SCCPs concentrations in the crab samples were different for different crab farms. Crab feed and the aquaculture environment could be sources of SCCPs to farmed crabs. No marked health risks are posed to humans through consuming CPs in Chinese mitten crabs farmed in China. [Display omitted] • SCCP concentrations in farmed crabs were much higher than MCCP concentrations. • Shorter carbon chain and less-chlorinated congeners dominated CPs in farmed crabs. • CP concentrations were highest in samples from the lower Yangtze River reaches. • Crab feed and aquaculture environment could be sources of SCCPs to farmed crabs. • Risks posed to humans through consuming CPs in farmed crabs were low. [ABSTRACT FROM AUTHOR]

The evaluation of toxicity related to polychlorinated dibenzo- p -dioxins and furans (PCDD/Fs) and dioxin-like polychlorinated biphenyls (DL-PCBs) is crucial for a comprehensive risk assessment in real-world exposure scenarios. This study employed a controlled feeding experiment to investigate the metabolic effects of dioxin-like compounds (DLCs) on laying hens via feed exposure. Diets enriched with two concentrations (1.17 and 5.13 pg toxic equivalents (TEQ)/g dry weight (dw)) were administered over 14 days, followed by 28 days of clean feed. Metabolomics analyses of blood samples revealed significant metabolic variations between PCDD/Fs and DL-PCBs exposed groups and controls, reflecting the induced metabolic disruption. Distinct changes were observed in sphingosine, palmitoleic acid, linoleate, linolenic acid, taurocholic acid, indole acrylic acid, and dibutyl phthalate levels, implying possible connections between PCDD/Fs and DL-PCBs toxic effects and energy-neuronal imbalances, along with lipid accumulation and anomalous amino acid metabolism, impacting taurine metabolism. Moreover, we identified three differential endogenous metabolites—L-tryptophan, indole-3-acetaldehyde, and indole acrylic acid—as potential ligands for the aryl hydrocarbon receptor (AhR), suggesting their role in mediating PCDD/Fs and DL-PCBs toxicity. This comprehensive investigation provides novel insights into the metabolic alterations induced by PCDD/Fs and DL-PCBs in laying hens, thereby enhancing our ability to assess risks associated with their exposure in human populations. [Display omitted] [ABSTRACT FROM AUTHOR]

• The g-C 3 N 4 /BiVO 4 photocatalyst was fabricated by ultrasound assisted synthesis method. • The n-n heterojunction is beneficial to the separation of photogenerated electron-hole pairs. • 10 wt% g-C 3 N 4 /BiVO 4 photocatalyst exhibited excellent degradation efficiency towards NP-9. • O 2 − and h+ are the main active species in the photocatalytic reaction. The g-C 3 N 4 /BiVO 4 heterojunction composites were successfully synthesized by ultrasound assisted method for better photocatalytic degradation of nonylphenol ethoxylate (NP-9, Tergitol) in water under the irradiation of visible light. The band gaps of BiVO 4 doped with 0–10 wt% g-C 3 N 4 were calculated from the absorption edge position ranges of 2.43–2.46 eV. The specific surface area of BiVO 4 composites increased from 1.6 m2/g to 16.3 m2/g by the increased doping of g-C 3 N 4 from 0 wt% to 40 wt%. In addition, the photocatalytic activity of g-C 3 N 4 /BiVO 4 for NP-9 degradation was evaluated under visible light irradiation. The results show that g-C 3 N 4 /BiVO 4 composites had higher activity than pristine BiVO 4 to give an excellent catalytic activity for NP-9 degradation. The improvement of activity after the recombination of g-C 3 N 4 and BiVO 4 is mainly due to the structure in heterojunctions with better visible light absorption and lower electron-hole pairs recombination rate. Furthermore, the 10 wt% g-C 3 N 4 /BiVO 4 with the highest activity gives the best photocatalytic performance when the initial pH of the solution is at 3 and the dosage of the catalyst is 0.5 g/L. At the same time, it exhibits sufficient catalytic stability in the cycled test. It is indicated that this heterogeneous photocatalyst has huge potential for the removal of organic pollutants. Moreover, it is demonstrated that h VB + and O 2 − are the main radicals in the photocatalytic reaction through the radicals trapping experiments. [ABSTRACT FROM AUTHOR]

• Both SCCPs and MCCPs were detected in plastic animal feed packaging samples. • The distributions and profiles of SCCPs and MCCPs varied in different packaging. • Time and temperature influenced the migration of CPs from the packaging. • Shorter chain and lower chlorinated congener groups were dominant in animal feed. Chlorinated paraffins (CPs) are used as plasticizers and flame retardants in plastics. Plastic packaging containing CPs is widely used for storage of animal feed, which can become contaminated by CPs that migrate into the feed. In the present study, 31 commercial animal feed packaging samples made of polypropylene (PP) or polyethylene (PE) were collected from animal feed manufacturers in China. The mean concentrations of short-chain chlorinated paraffins (SCCPs) in the PP and PE samples were 60.0 and 54.5 μg/g, respectively. The medium-chain chlorinated paraffin (MCCP) mean concentrations in the PP and PE samples were 62.7 and 9.23 μg/g, respectively. The carbon congener group profiles of SCCPs and MCCPs in the samples were different. The dominant SCCP and MCCP chlorine congener groups in all the samples were Cl 6–7 and Cl 6–8 , respectively. Time and temperature influenced the migration of CPs from packaging into animal feed. As the time or temperature increased, the CP concentrations in the animal feed increased but the congener group profiles of the SCCPs and MCCPs in the animal feed did not change. To reduce contamination of animal feed by CPs, it is necessary to restrict the use of CPs in animal feed packaging. [ABSTRACT FROM AUTHOR]

• High SCCP and MCCP concentrations were found in raw cow milk from industrial areas. • SCCP concentrations in raw milk and silage were higher than MCCP concentrations. • Animal feed might be an important source of dairy cow exposure to SCCPs and MCCPs. • Bioconcentration factors for SCCPs and MCCPs in cow milk were calculated. • The exposure of Chinese residents to SCCPs and MCCPs via cow milk is minimal. Chlorinated paraffins (CPs) are industrial chemicals that are produced in large quantities and used globally. Human exposure to CPs is primarily through dietary intake, especially from animal-derived food products. Even so, there is little information regarding CP concentrations in dairy products. In this study, raw samples of cow milk were collected from various regions in China within the Neimenggu (n = 10), Hebei (n = 9), Shandong (n = 10), Henan (n = 10) and Hubei (n = 9) provinces. The mean concentrations of short chain CPs (SCCPs) and medium chain CPs (MCCPs) in the milk samples from industrial areas (1670 and 190 ng/g lipid, respectively) were higher than those from non-industrial areas (490 and 72 ng/g lipid, respectively). In most samples, C 10 H 16 Cl 6 and C 14 H 23 Cl 7 were the primary SCCP and MCCP congener groups, respectively. The mean concentrations of SCCPs and MCCPs in dairy cow feed (silage) were determined to be 750 and 36 ng/g dry weight, respectively. The SCCP and MCCP congener group patterns in the milk were similar to those in the silage, indicating that animal feed intake might be an important pathway for the exposure of dairy cows to CPs. Thus, the ingestion of CPs by humans through dairy products should not be neglected and the contamination of animal feed by CPs should be considered. [ABSTRACT FROM AUTHOR]

• PFAA levels were investigated in current commonly used protein feeds. • The highest PFAA levels were observed in blood meal. • Length-specific PFAA profiles were evaluated among five categories protein feeds. • Plant-origin and terrestrial-origin feeds were susceptible to short-chain PFAAs. Animal protein supplement feeds (APFs) are susceptible to perfluoroalkyl acids (PFAAs) and could be the main sources for raised animals, thereafter causing further human exposure through the farm-to-fork pathway. However, the occurrence of PFAAs has been rarely evaluated in various APFs, especially for emerging short-chain PFAAs. In the present study, we collected the most prevalent APFs (blood meal, meat meal, feather meal, soybean meal and DDGS) and found that Σ 16 PFAAs ranged from undetectable to 37.1 ng/g dry weight (dw) (average: 7.23 ng/g dw). Blood meal contained the highest PFAA levels, and results revealed that some terrestrial-derived APFs might be present at levels on par with the marine-derived feed. Animal-derived APFs (mean 10.9 ng/g dw) possessed higher ∑PFAAs than plant-derived APFs (0.75 ng/g dw). Length-specific PFAA profiles were specified between terrestrial-origin and marine-origin feeds in addition to animal-derived and plant-derived feeds. Short-chain PFAAs (PFBA, PFBS and PFHxS) were primarily found in blood meal, meat meal, soybean meal and DDGS, while the long-chain counterparts dominated in feather meal. It is of great concern that feed exposure to emerging contaminants has not drawn enough attention. [ABSTRACT FROM AUTHOR]

Full waveform inversion is a nonlinear fitting technique that requires regularization methods to alleviate ill-posedness. Based on the newly introduced Graph-Laplacian regularization, which offers outstanding manifold learning, we propose a novel regularization method for FWI that can combine the graph Laplacian matrix with a sparse representation in a learning-based dictionaries. Besides employing an adaptive sparsity prior, the graph Laplacian matrix incorporates the nonlocal self-similarity prior into the FWI process, and consequently improve the stability of the inversion process and produce more accurate inversion results. The Alternating Direction Method of Multipliers (ADMM) is applied to solve the problem numerically. A series of experiments are performed on the Marmousi model and the BG Compass model. The experimental results verify the effectiveness of the proposed FWI method in both quantitative analysis and visual perception. • The graph Laplacian regularizer combines with an adapted dictionary. • Graph Laplacian matrix incorporates the self-similarity prior into the FWI process. • The ADMM framework improves the FWI quality. [ABSTRACT FROM AUTHOR]

Chitosan/poly(ethylene oxide)/permutit (CS/PEO/PT) composite nanofibers were prepared via electrospinning and their potential application in the removal of hexavalent chromium (Cr(vi)) from aqueous solutions was studied in detail. SEM results showed that the nanofibers were homogeneous and bead-free. XRD and DSC results demonstrated that there were strong interactions among CS, PEO and PT. The solubility test showed that the CS/PEO/PT composite membrane had excellent durability in water. The CS/PEO/PT-1% nanofibers exhibited the best adsorption performance for Cr(vi) ions in acidic solution (pH = 3) and at a low Cr(vi) concentration of 50 mg L−1. The maximum adsorption capacity reached 208 mg g−1. The adsorption kinetics and equilibrium data were well described by pseudo-second-order kinetic and Langmuir isotherm models, respectively. According to the results of FTIR and XPS analyses, protonation, ion exchange, electrostatic interactions and redox reactions were involved in the adsorption process. All the results indicated that the electrospun CS/PEO/PT nanofibers could be used as promising absorbents for the removal of Cr(vi). [ABSTRACT FROM AUTHOR]

The treatment of large-area bone defects remains a challenge; however, various strategies have been developed to improve the performances of scaffolds in bone tissue engineering. In this study, poly(lactide-co-glycolide)/hydroxyapatite (PLGA/HA) scaffold was coated with Asp-Gly-Glu-Ala (DGEA)-incorporated collagen for the repair of rat skull defect. Our results indicated that the mechanical strength and hydrophilicity of the PLGA/HA scaffold were clearly improved and conducive to cell adhesion and proliferation. The collagen-coated scaffold with DGEA significantly promoted the repair of skull defect. These findings indicated that a combination of collagen coating and DGEA improved scaffold properties for bone regeneration, thereby providing a new potential strategy for scaffold design. [ABSTRACT FROM AUTHOR]

Low-level laser could promote osteoblast proliferation, and it has been applied in clinical practice to promote wound healing and tissue regeneration. However, the mechanism related to laser irradiation remains unclear. This study aimed to investigate the effects of low-level laser irradiation on the cell proliferation and the expressions of hedgehog signaling molecules Indian hedgehog (Ihh), Ptch, and Gli in vitro. In our present study, the MTT method was used to evaluate the effect on cell proliferation of laser irradiation on MC3T3-E1 cells. And cell cycle was examined by flow cytometry. Gene and protein expressions of hedgehog signaling molecules, including Ihh, Ptch, Smoothened (Smo), and Gli, were examined by qRT-PCR and western blot analysis. The results showed that laser irradiation at dosage of 3.75 J/cm enhances the proliferation of MC3T3-E1 cells compared with control groups ( p = 0.00). Moreover, laser irradiation (3.75 J/cm) increased the cell amount at S phase ( p = 0.00). In addition, the expressions of Ihh, Ptch, Smo, and Gli were significantly increased compared to the control during laser irradiation (3.75 J/cm)-induced MC3T3-E1 osteoblast proliferation. After adding the hedgehog signaling inhibitor CY (cyclopamine), cell proliferation and Ihh, Ptch, Smo, and Gli expressions were inhibited ( p = 0.00), and the cell amount at S phase was reduced compared with combination groups ( p = 0.00). These results indicated that laser irradiation promotes proliferation of MC3T3-E1 cells through hedgehog signaling pathway. Our findings provide insights into the mechanistic link between laser irradiation-induced osteogenesis and hedgehog signaling pathway. [ABSTRACT FROM AUTHOR]

Over 9000 types of per- and polyfluoroalkyl substances (PFASs) have been produced that exhibit environmental persistence, bioaccumulation and biotoxicity, and pose a potential hazard to human health. Although metal–organic frameworks (MOFs) are promising structure-based materials for adsorbing PFASs, the enormous structural diversity and variability of the pharmacologic action of PFASs present challenges to the development of structure-based adsorbents. To address this issue, we propose an in situ platform for the high-throughput identification of efficient MOF sorbents that can adsorb PFASs and their metabolism using a filter-chip-solid phase extraction-mass spectrometry (SPE-MS) system. As a proof of concept, we screened BUT-16 as an attractive material for in situ fluorotelomer alcohol (FTOH) adsorption. The results demonstrated that FTOH molecules were adsorbed around the surface of the large hexagonal pores of BUT-16 by forming multiple hydrogen bonding interactions with its Zr6 clusters. The FTOH removal efficiency of the BUT16 filter was 100% over a period of 1 min. To determine the FTOH metabolism effects in different organs, HepG2 human hepatoma, HCT116 colon cancer, renal tubular HKC, and vascular endothelial HUVEC cells were cultured on a microfluidic chip, and SPE-MS was used to track a variety of cell metabolites in real time. Overall, the filter-Chip-SPE-MS system is a versatile and robust platform for the real-time monitoring of noxious pollutant detoxification, biotransformation, and metabolism, which facilitates pollutant antidote development and toxicology assay. [ABSTRACT FROM AUTHOR]

Polychlorinated naphthalenes (PCNs) are candidates for inclusion in the Stockholm Convention on persistent organic pollutants. PCNs are structurally and toxicologically similar to 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD) and its analogues. Intake in food is considered to be an important human exposure pathway for PCNs. In this preliminary study, cheese and butter samples were analysed for PCNs, polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and polychlorinated biphenyls (PCBs) using an isotope dilution gas chromatography high-resolution mass spectrometry method. The aim of this study was to evaluate the PCN concentrations in the cheese and butter samples and to compare them with the PCDD, PCDF and PCB concentrations. The PCN concentrations were 5.6–103 pg g−1of wet weight in the seven cheese samples tested and 5.0–199 pg g−1of wet weight in the seven butter samples tested. The mass concentrations of lower chlorinated congeners were greater than those of the higher chlorinated congeners. Congeners of CN45/36, CN27/30 and CN33/34/37 were much more abundant than other congeners found in tetrachlorinated PCNs. Congeners of CN51, CN66/67 and CN73 were determined to be the predominant congeners in penta-, hexa- and heptachlorinated homologs, respectively. The PCNs contributed around 5% of the total PCN, PCDD, PCDF and PCB toxic equivalence (TEQ) values. CN73 was found to be the dominant PCN congener and contributed more than 40% to the PCN TEQ value. Congeners CN66/67, CN69 and CN63 were also found at relatively high levels. The PCB congener CB118 was the predominant congener (by mass-based concentration) of the 12 dioxin-like PCBs (dl-PCBs). The PCBs contributed 53.8% of the total TEQ, and congener CB126 contributed more than any other compound that was analysed to the total TEQ. The PCDDs and PCDFs contributed 11.6% and 29.7% of the total TEQ values, respectively. [ABSTRACT FROM PUBLISHER]

Nanostructure engineering and carbon incorporation can effectively achieve superior lithium storage performance of SiO2 anode. However, the working operation at high rates and extreme temperatures remains a challenge for SiO2-based anode. Here, SiO2@N-doped carbon (SiO2@NC) nanospheres encapsulated in the TiN/C nanofibers (SiO2@NC@TiN/C) were fabricated via coaxial electrospinning. The SiO2@NC@TiN/C with a robust structure and conductive shells exhibited excellent cycling stability and fast Li+ diffusion kinetics. The SiO2@NC@TiN/C electrode delivered a superior rate performance (317.9 mAh g−1) and ultra-long cycle life (284.5 mAh g−1 after 3200 cycles) at 10 A g−1. Furthermore, the SiO2@NC@TiN/C electrode maintained an excellent cycling stability at 65 ℃ (420.6 mAh g−1 after 300 cycles at 1 A g−1). This research offered an ingenious design way to create a multilayer coated anode, which could exhibit good electrochemical performance under harsh conditions. [ABSTRACT FROM AUTHOR]

Objective: PE is a pregnancy‐specific syndrome that affects 3%–5% of pregnant women. It often presents as new‐onset hypertension and proteinuria during the third trimester. PE progresses rapidly and may lead to serious complications, including the death of both mother and fetus. In low‐income countries, PE is one of the main causes of maternal and child mortality. While the cause of PE is still debated, clinical and pathological studies suggest that the placenta plays an important role in the pathogenesis of PE. Materials and Methods: In this single‐cell RNA‐sequencing (RNA‐seq) study, the placenta was taken from the designated position after cesarean section. We compared placental cell subsets and their transcriptional heterogeneity between preeclampsia and healthy pregnancies using the single‐cell RNA‐seq technology. A developmental trajectory of human trophoblasts was shown. Results: Gene expression in endoplasmic reticulum signaling pathways in syncytiotrophoblast was upregulated in the PE group. The villi cytotrophoblasts (VCT) and extravillous trophoblasts were mainly involved in immune responses. Conclusion: The placental immune function of patients with PE was altered. Proteasomes, spliceosomes, ribosomes, and mitochondria were abnormally active in the new VCT cell type. [ABSTRACT FROM AUTHOR]

Chlorinated paraffins (CPs) are hazardous to humans, and dietary intake acts as the primary pathway for human exposure to CPs. Takeout food is popular worldwide, but the presence of CPs in takeout food and its packaging is unclear. In this study, the concentrations and distributions of short- and median-chain CPs (SCCPs and MCCPs, respectively) were measured in 97 samples of four categories of takeout food and 33 samples of three types of takeout packaging. The SCCP and MCCP median concentrations for the takeout food samples were 248 and 339, 77.2 and 98.2, 118 and 258, 42.9 and 64.4 ng/g wet weight in meat, starch, half meat/half starch, and vegetables, respectively. Takeout food contained higher concentrations of SCCPs than MCCPs. The dominant SCCP and MCCP congener groups in takeout food were C 10 Cl 6–7 and C 14 Cl 7–8 , respectively. The CP concentrations in takeout food were lower than those in packaging. The SCCP and MCCP median concentrations, respectively, in packaging were 9750 and 245 ng/g in polypropylene, 2830 and 135 ng/g in paper, and 2060 and 119 ng/g in aluminum foil. The concentrations of SCCPs and MCCPs were comparable in aluminum foil, whereas the concentrations of SCCPs were higher than those of MCCPs in polypropylene and paper. Correlations between CP concentrations in the takeout food and packaging indicated that CPs in packaging were potentially an important source of CPs in the takeout food. A dietary exposure risk assessment showed the takeout food posed a low risk for human exposure to CPs; however, high-frequency consumption may pose a health risk. This study clarified the current contamination situation in takeout food in Beijing, China. The resulting data could be used to prevent human exposure to CPs through dietary intake and to facilitate the market's control over the quality of takeout food. • Chlorinated paraffin (CP) concentrations are highest in animal-origin takeout food. • CP concentrations are highest in polypropylene and lowest in aluminum foil. • Shorter carbon chain and lower chlorination CPs are dominant in food and packaging. • CPs in packaging are a potential source for CPs in takeout food. • The human exposure risk to CPs through takeout food intake is low. [ABSTRACT FROM AUTHOR]

Animal-derived food plays an important role in human exposure to bisphenol compounds (BPs), potentially as a result of the presence of BPs in animal feed. Even so, there have been few studies regarding the source of BPs in animal feed. The objective of the present study was to assess both the occurrence of BPs in animal feed packaging and the migration of BPs from feed packaging into animal feed. Thirteen BPs were monitored in 30 used animal feed plastic packaging samples previously employed for different animal feedstuffs and made of polypropylene (PP) or polyethylene (PE). Six and two BPs were found in PP-based woven bags and PE-based films, respectively. Bisphenol A (BPA) was the predominant analogue with a wide range of concentrations in both the PP- and PE-based packaging. A migration experiment was performed and provided the first-ever confirmation that BPA is able to migrate from plastic packaging into solid feed. Both contact time and the initial BP concentration affected the extent of migration. These results expand our knowledge regarding the origin of BPs in the food chain and suggest that further study of the bioaccumulation of BPs in animals is warranted. Image 1 • The potential for BPs to enter animal feed from plastic packaging was assessed. • Several BPs were found in animal feed plastic packaging and BPA was predominant. • BPA was found to migrate from plastic packaging into solid animal feed. • BPA levels in packaging and contact time were the main factors determining migration. [ABSTRACT FROM AUTHOR]

Chitosan (CS) based nanofibrous membranes were fabricated via hybrid electrospinning of chitosan (CS) and poly(ε-caprolactone) (PCL) or poly(ε-caprolactone)-block-poly(ethylene glycol) (PCL-b-PEG) copolymers for the adsorption of dyes from aqueous solution. The amphiphilic block polymers were obtained by polymerization of PCL and different molecular weights of PEG. It was observed that the secondary fiber and core–shell structure could be controlled by PEG segments. The results of XPS showed that as the molecular weight of the PEG segments increased, the content of CS on the fiber surface increased. The parameters of adsorption time, initial concentration and pH values on the adsorption capacity were studied. The adsorption experiments showed that the adsorption process toward Congo red (CR) on CS-based membranes fitted well with the pseudo-second-order model and Langmuir isotherm model. The CS-based membranes with PEG molecular weight of 5 kDa possessed good reusability and the maximum adsorption capacity calculated from the Langmuir model was 291.55 mg g−1. The existence of intermolecular hydrogen bonds between CS and PCL-b-PEG copolymer reduced the loss of CS. Therefore, CS-based membranes would be promising materials for water remediation. [ABSTRACT FROM AUTHOR]

Osteoarthritis (OA) is a synovial inflammatory condition characterized by cartilage destruction and osteophyte formation. Macrophages play a central role in OA pathogenesis by producing proinflammatory cytokines. Intra-articular corticosteroid administration can relieve refractory pain and inflamed effusion of knee joints. However, limitations, such as rapid clearance from the joint space, potential damage to articular cartilage, and accelerated joint degeneration, may hamper the clinical application of corticosteroids. In this study, we reported the design and preparation of dextran sulfate-triamcinolone acetonide conjugate (DS-TA) nanoparticles (NPs) for treating OA by specifically targeting scavenger receptor class A (SR-A) on activated macrophages. We verified the excellent targeting specificity of DS-TA NPs to SR-A by flow cytometry and confocal laser scanning microscopy. DS-TA NPs were found to effectively reduce the viability of activated macrophages (RAW 264.7 cells) and the expression of proinflammatory cytokines. Intra-articular injection of DS-TA NPs effectively alleviated the structural damages to the joint cartilage, as confirmed in histopathological analysis. Additionally, DS-TA NPs decreased the expression of proinflammatory cytokines, including IL-1β, IL-6, and TNF-α, in the cartilage tissue. Thus, DS-TA NPs are a potential therapeutic nanomedicine for the targeted treatment of OA. • Dextran sulfate-triamcinolone acetonide conjugate (DS-TA) is synthesized and self-assembled into micellar nanoparticles. • The obtained DS-TA NPs specifically targeted scavenger receptor class A (SR-A) on the surface of activated macrophages • DS-TA NPs inhibited the proliferation of activated macrophages and decreased the expression of proinflammatory cytokines. • DS-TA NPs effectively alleviated the structural damage of joint cartilage and the loss of subchondral bone. • DS-TA NPs are promising for targeted treatment of OA. [ABSTRACT FROM AUTHOR]

κ-Carrageenases are desirable tools for tailoring the molecular weight, physicochemical properties and functionalities of κ-carrageenan, a macromolecule widely utilized in various industries. In this study, a novel GH16 family κ-carrageenase, designated as Cgk16A, was cloned from the genome of marine bacterium Wenyingzhuangia aestuarii OF219 and expressed in Escherichia coli . Its biochemical properties, kinetic parameters and hydrolytic pattern were characterized. The enzyme demonstrated a low optimal reaction temperature (25 °C) and a cold-adapted feature. As an endo-acting glycoside hydrolase, Cgk16A degraded κ-carrageenan in a random manner, and it was competent to prepare the degradation products with varying degrees of polymerization. The mass spectrometry analysis revealed that the end products of Cgk16A were majorly composed of κ-carrageenan tetrasaccharide with a minor portion of disaccharide. The enzyme showed higher enzyme-substrate affinity over all hitherto characterized GH16 κ-carrageenases, indicated by its low K m value (0.17 μM). Cgk16A could be employed as a potential biotechnological tool for depolymerizing κ-carrageenan, which would facilitate the future application of κ-carrageenan and its degradation products. [ABSTRACT FROM AUTHOR]

Low-level laser could promote osteoblast proliferation, and it has been applied in clinical practice to promote wound healing and tissue regeneration. However, the mechanism related to laser irradiation remains unclear. This study aimed to investigate the effects of low-level laser irradiation on the cell proliferation and the expressions of hedgehog signaling molecules Indian hedgehog (Ihh), Ptch, and Gli in vitro. In our present study, the MTT method was used to evaluate the effect on cell proliferation of laser irradiation on MC3T3-E1 cells. And cell cycle was examined by flow cytometry. Gene and protein expressions of hedgehog signaling molecules, including Ihh, Ptch, Smoothened (Smo), and Gli, were examined by qRT-PCR and western blot analysis. The results showed that laser irradiation at dosage of 3.75 J/cm2 enhances the proliferation of MC3T3-E1 cells compared with control groups (p = 0.00). Moreover, laser irradiation (3.75 J/cm2) increased the cell amount at S phase (p = 0.00). In addition, the expressions of Ihh, Ptch, Smo, and Gli were significantly increased compared to the control during laser irradiation (3.75 J/cm2)-induced MC3T3-E1 osteoblast proliferation. After adding the hedgehog signaling inhibitor CY (cyclopamine), cell proliferation and Ihh, Ptch, Smo, and Gli expressions were inhibited (p = 0.00), and the cell amount at S phase was reduced compared with combination groups (p = 0.00). These results indicated that laser irradiation promotes proliferation of MC3T3-E1 cells through hedgehog signaling pathway. Our findings provide insights into the mechanistic link between laser irradiation-induced osteogenesis and hedgehog signaling pathway. [ABSTRACT FROM AUTHOR]

There is very little information on the levels and particle size distributions of lower chlorinated dibenzo- p -dioxins and dibenzofurans (mono- to tri-CDD/Fs, ΣCl 1–3 DD/Fs) in the atmosphere, while a number of studies have examined tetra- to octa-chlorinated homologues (ΣCl 4–8 DD/Fs). In this study, we measured the concentration and particle size distribution of ΣCl 1–3 DD/Fs in ambient air in suburban Beijing and compared them with that of ΣCl 4–8 DD/Fs for the first time. The mean concentration of ΣCl 1–3 DD/Fs was 54.63 pg m −3 , which is about 5.4 times that of ΣCl 4–8 DD/Fs. The ΣCl 1–3 DD/Fs accounted for 85% of ΣCl 1–8 DD/Fs, and MoCDFs made up the largest proportion (43%) of PCDD/F homologues. The ΣCl 1–3 DD/Fs mainly occurred in the gas phase, while the ΣCl 4–8 DD/Fs mainly occurred in the particulate phase. The majority of ΣCl 1–3 DD/Fs (70%) occurred in d ae > 1.0 μm particles, which is the reverse of the trend observed for ΣCl 4–8 DD/Fs, of which 78% occurred in d ae < 1.0 μm particles. The observed high concentrations of ΣCl 1–3 DD/Fs and different distribution patterns demonstrate that it is necessary to consider the lower chlorinated homologues to improve our understanding of the environmental behavior and health risk assessments of PCDD/Fs in the atmosphere. [ABSTRACT FROM AUTHOR]

A comprehensive comparison of the levels and profiles of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/F) in fly ash samples from multiple industrial sources may help to prioritize sources and to understand discrepancies in profiles. In this study, PCDD/F data from 113 fly ash samples from 14 sources reported in previous studies were summarized and compared. The highest PCDD/F levels occurred in samples from secondary copper smelting (SCu). Although PCDD/F levels from secondary zinc smelting (SZn) were slightly lower than those of SCu, the PCDD/F profiles varied widely between the two sources. For SCu, more chlorinated homologs were dominant, with highest degrees of chlorination being 6.6 for PCDF and 7.2 for PCDD. For SZn, less chlorinated homologs were dominant, with lowest degrees of chlorination being 4.4 for PCDF and 4.8 for PCDD. We speculate that copper and zinc might promote PCDD/F formation by catalyzing different pathways of thermal reactions. Diagnostic ratios of specific PCDD/F congeners for different sources were suggested to identify potential sources of PCDD/Fs in the environment. Equations describing correlations between congeners and PCDD/F toxic equivalents were established, which may be useful for rapid and inexpensive screening of the toxic levels of PCDD/Fs in fly ash samples. [ABSTRACT FROM AUTHOR]