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Roles of bulk and rhizosphere denitrifying bacteria in paddy soil denitrification under straw return conditions are rarely discriminated, limiting our understanding on nitrogen biogeochemistry in soils amended with straw. The objective of this study was to explore the microbial mechanisms accounting for the altered rhizosphere and bulk soil denitrification with straw amendment. In this study, straw was added into two representative paddy soils (0.5% w/w) from Yixing (YX) and Taizhou (TZ) in Jiangsu city, China, for rice growth over a 37-day period. Denitrification potentials (net N2O emission, total denitrification, and N2O reduction rates) of rhizosphere and bulk soils at the end of rice growth were measured using an acetylene inhibition technique. In addition, denitrifying bacterial community compositions and functional gene abundances were analyzed using Illumina sequencing and quantitative real-time PCR. For control treatment without straw addition, total denitrification and N2O reduction rates were significantly higher in the rhizosphere than that in bulk soils; however, net N2O emission potentials were similar between rhizosphere and bulk for TZ (22.6–53.3 vs. 9.44–46.6 mg N kg−1) and YX (946 ± 126 vs. 699 ± 350 mg N kg−1). Under straw return condition, N2O emission potentials from the bulk of both soils were significantly elevated, corresponding to the increase in the relative abundance of some taxa of denitrifying bacteria (unnamed environmental samples and unclassified proteobacteria) and increase in nirK, nirS, and nosZ genes. This indicates a positive response of bulk soil denitrifying bacteria to straw addition. In contrast, straw addition produced inhibitive effects on the growth of denitrifying bacteria with decreased nirK, nirS, and nosZ gene abundances in the rhizosphere. This led to decreased N2O emission potentials at the end of incubation for rhizosphere soils, which were 98.2% and 25.2% lower for TZ and YX compared to those of bulk soils. These results suggested that the roles of bulk and rhizosphere denitrifying bacteria in paddy soil denitrification shifted with straw addition, which might inspire further studies to target the denitrification hotspots to effectively mitigate greenhouse emissions at the early period of rice growth.

Objectives The humid oral environment adversely affects the interaction between a functionalised primer and dentine collagen after acid-etching. Robust adhesion of marine mussels to their wet substrates instigates the quest for a strategy that improves the longevity of resin-dentine bonds. In the present study, an etching strategy based on the incorporation of biomimetic dopamine methacrylamide (DMA) as a functionalised primer into phosphoric acid etchant was developed. The mechanism and effect of this DMA-containing acid-etching strategy on bond durability were examined. Methods Etchants with different concentrations of DMA (1, 3 or 5 mM) were formulated and tested for their demineralisation efficacy. The interaction between DMA and dentine collagen, the effect of DMA on collagen stability and the collagenase inhibition capacity of the DMA-containing etchants were evaluated. The effectiveness of this new etching strategy on resin-dentine bond durability was investigated. Results All etchants were capable of demineralising dentine and exposing the collagen matrix. The latter strongly integrated with DMA via covalent bond, hydrogen bond and Van der Waals’ forces. These interactions significantly improve collagen stability and inhibited collagenase activity. Application of the etchant containing 5 mM DMA achieved the most durable bonding interface. Conclusion Dopamine methacrylamide interacts with dentine collagen in a humid environment and improves collagen stability. The monomer effectively inactivates collagenase activity. Acid-etching with 5 mM DMA-containing phosphoric acid has the potential to prolong the longevity of bonded dental restorations without compromising clinical operation time. Clinical Significance The use of 5 mM dopamine methacrylamide-containing phosphoric acid for etching dentine does not require an additional clinical step and has potential to improve the adhesive performance of bonded dental restorations.

Toxoplasmosis post serious threaten to human health, leading to severely eye and brain disease, especially for immunocompromised patients and pregnant women. The multiple side effects and long dosing period of current main treatment regiments calls for high effective and low toxicity anti-toxoplasmosis drugs. Herein, we report our efforts to synthesize a series of 2-(piperazin-1-yl)quinazolin-4(3 H )-one derivatives and investigate their acivity against Toxoplasma gondii tachyzoites in vitro based on cell phenotype screening. Among the 26 compounds, 8w and 8x with diarylether moiety at the side chain of piperazine exhibited good efficacy to inhibit T . gondii, with IC 50 values of 4 μM and 3 μM, respectively. Structure-activity relationship (SAR) studies implies that hydrophobic aryl at the side chain would be preferred for improvement of activity. Molecular docking study reveales these two compounds appeared high affinity to Tg CDPK1 by interaction with the hydrophobic pocket of ATP-binding cleft.two compounds appeared high affinity to Tg CDPK1 by interaction with the hydrophobic pocket of ATP-binding cleft.

Refereed/Peer-reviewed Ingestion of metal-contaminated soils poses risks to human health. To accurately assess the risks, in vitro assays have been developed to measure metal bioaccessibility. However, they often differ considerably in gastrointestinal fluid components and assay parameters, leading to inconsistent bioaccessibility results. As such, in vitro assays need to be validated against in vivo bioassays based on in vivo-in vitro correlations (IVIVCs). To help researchers to select the best in vitro assay and increase the robustness of the IVIVCs, there is a need to review and compile existing data. In this review, we focus on three metals (As, Pb, and Cd), five common in vitro assays (SBRC, UBM, IVG, DIN, and PBET), and two in vivo bioassays (mouse and swine models). Specifically, we 1) discuss variations in metal bioaccessibility measurements among different in vitro assays, 2) identify the roles of major gastrointestinal fluid constitutes and assay parameters in affecting metal bioaccessibility, 3) summarize weaknesses associated with existing IVIVCs, and 4) establish new IVIVCs using pooled soil samples from different studies. In addition, future research directions are highlighted, including better understanding of the roles of gastrointestinal fluid components, improving in vitro assays to better correlate with in vivo bioassays, expanding bioaccessibility measurements using different in vitro assays, validation of IVIVCs using independent soils, assessing the reliability of in vitro assays in remediated soils, and addressing the mechanisms behind IVIVCs.

Rice consumption is a major dietary source of human exposure to arsenic (As), with As bioavailability being an important factor influencing its health risk. In this study, the As bioaccessibility was measured in 11 rice grains (140–335 μg As kg−1), which were compared to As relative bioavailability previously measured based on a mouse bioassay (Li et al., 2017). Using modified physiologically-based extraction test for rice (MPBET), As bioaccessibility in raw rice samples (44–88% in the gastric phase and 47–102% in the intestinal phase) was similar to those in cooked rice (42–73% and 43–99%). Arsenic bioaccessibility in rice was generally higher in the intestinal phase than in the gastric phase, with Fe and Ca concentrations in rice being negatively correlated with As bioaccessibility in the gastric phase (R2 = 0.47–0.49). In addition, for cooked rice, strong positive correlation was observed between bioaccessible As and inorganic As (R2 = 0.63–0.72), suggesting inorganic As in rice was easier to dissolve than organic As in gastrointestinal digestive fluids. Due to limited variation in As bioaccessibility and As bioavailability among the 11 samples, a weak correlation was observed between them (R2 = 0.01–0.03); however, As bioaccessibility values measured by the gastric phase (GP) of the MPBET agreed with As bioavailability values based on a mouse bioassay, suggesting the potential of the MPBETGP to predict As bioavailability in rice. Future work is needed to ascertain the robustness of the MPBETGP in predicting As bioavailability in rice using additional samples.

Animal bioassays have been developed to estimate oral relative bioavailability (RBA) of metals in soil, dust, or food for accurate health risk assessment. However, the comparability in RBA estimates from different labs remains largely unclear. Using 12 soil and soil-like standard reference materials (SRMs), this study investigated variability in lead (Pb) and arsenic (As) RBA estimates employing a mouse bioassay in 3 labs at Nanjing University, University of Jinan, and Shandong Normal University. Two performances of the bioassay at Nanjing University in 2019 and 2020 showed reproducible Pb and As RBA estimates, but increasing the number of mouse replicates in 2020 produced more precise RBA measurements. Although there were inter-lab variations in diet consumption rate and metal accumulation in mouse liver and kidneys following SRM ingestion due to differences in diet composition, bioassays at 3 labs in 2019 yielded overall similar Pb and As RBA estimates for the 12 SRMs with strong linear correlations between each 2 of the 3 labs for Pb (R2 = 0.95–0.98 and slope = 0.85–1.02) and As RBA outcomes (R2 = 0.46–0.86 and slope = 0.56–0.79). The consistency in RBA estimates was attributed to the relative nature of the final bioavailability outcome, which might overcome the inter-lab variation in diet consumption and metal uptake in mice. These results increased the confidence of use of mouse bioassays in bioavailability studies. Refereed/Peer-reviewed

Oral bioavailability of arsenic (As) determines levels of As exposure via ingestion of As-contaminated soil, however, the role of gut microbiota in As bioavailability has not evaluated in vivo although some in vitro studies have investigated this. Here, we made a comparison in As relative bioavailability (RBA) estimates for a contaminated soil (3913 mg As kg−1) using a mouse model with and without penicillin perturbing gut microbiota and metabolites. Compared to soil exposure alone (2% w/w soil in diets), addition of penicillin (100 or 1000 mg kg−1) reduced probiotic Lactobacillus and sulfate-reducing bacteria Desulfovibrio, enriched penicillin-resistant Enterobacter and Bacteroides, and decreased amino acid concentrations in ileum. With perturbed gut microbiota and metabolic profile, penicillin and soil co-exposed mice accumulated 2.81–3.81-fold less As in kidneys, excreted 1.02–1.35-fold less As in urine, and showed lower As-RBA (25.7–29.0%) compared to mice receiving diets amended with soil alone (56 ± 9.63%). One mechanism accounted for this is the decreased concentrations of amino acids arising from the gut microbiota shift which resulted in elevated iron (Fe) and As co-precipitation, leading to reduced As solubilization in the intestine. Another mechanism was conversion of bioavailable inorganic As to less bioavailable monomethylarsonic acid (MMAV) and dimethylarsinic acid (DMAV) by the antibiotic perturbed microflora. Based on in vivo mouse model, we demonstrated the important role of gut microbiota and gut metabolites in participating soil As solubilization and speciation transformation then affecting As oral bioavailability. Results are useful to better understand the role of gut bacteria in affecting As metabolism and the health risks of As-contaminated soils Refereed/Peer-reviewed

Geogenic Ni exposure via food consumption and soil ingestion was assessed by analyzing Ni concentration and oral bioavailability in soil, wheat, and rice Accumulation and oral bioavailability of nickel (Ni) were rarely assessed for staple crops grown in high geogenic Ni soils. To assess exposure risk of geogenic Ni, soil, wheat, and rice samples were collected from a naturally high background Ni area and measured for Ni oral relative bioavailability (RBA, relative to NiSO4) using a newly developed mouse urinary Ni excretion bioassay. Results showed that soils were enriched with Ni (80.5 ± 23.0 mg kg−1, n = 58), while high Ni contents were observed in rice (2.66 ± 1.46 mg kg−1) and wheat (1.32 ± 0.78 mg kg−1) grains, with rice containing ∼2-fold higher Ni content than wheat. Ni-RBA was low in soil (14.8 ± 7.79%, n = 18), but high in wheat and rice with rice Ni-RBA (85.9 ± 19.1%, n = 9) being ∼2-fold higher than wheat (46.1 ± 21.2%, n = 16). A negative correlation (r = 0.61) was observed between Ni-RBA and iron content in rice and wheat, suggesting the low iron status of rice drives its high Ni bioavailability. The higher Ni accumulation and bioavailability for rice highlights that rice consumption was a more important contributor to daily Ni intake compared to wheat, while Ni intake from direct soil ingestion was negligible. This study suggests a potential health risk of staple crops especially rice when grown in high geogenic Ni areas. Refereed/Peer-reviewed

Incidental soil ingestion is considered to be an important route of exposure to hydrophobic organic contaminants(HOCs), such as dichlorodiphenyl-trichloroethane (DDT).Contaminant ingestion often occurs during food consumption;however, knowledge on the influence of food on DDT bioavailability remains limited. In this study, the relative bioavailability (RBA) of soil DDTr (i.e., DDT and metabolites)was determined using an in vivo mouse model in the presence of eight kinds of food including rice, egg, pork, pear, soybean, bread,spinach, and milk powder. The values of DDTr-RBA ranged from19.8 ± 10.9 to 114 ± 25.1%. DDTr-RBA was positively correlated with fat (r = 0.71) and negatively correlated with fiber (r = 0.63) content in food. A mechanistic study showed that fat enhanced micellarization and promoted the formation of chylomicron, which facilitated the dissolution and transport of DDTr in the intestinal tract. Bioaccessibility of DDTr was determined using a physiologically based in vitro method. The addition of lipase significantly improved the ability of the method to predict DDTr-RBA, indicating that the “fasted state” in vitro method required optimization for food scenarios. To the best of our knowledge, this is the first study to explore the mechanistic influence of food on DDTr-RBA and provide important knowledge on dietary approaches for reducing exposure to HOCs. Refereed/Peer-reviewed

To understand how Cd in different fractions contributes to Cd bioaccessibility by in vitro assays, Cd bioaccessibility in 12 contaminated soils was determined by four assays (UBM, SBRC, IVG, and PBET) and correlated with different Cd fractions based on a sequential extraction scheme. The Cd bioaccessibility in the gastric phase (GP) was high (35–107%, averaging at 77%), implicating high risk to human health, while it decreased to 19–88% averaging at 47% in the intestinal phased (IP). From the GP to IP, the reduction of extractable Cd (0.45–48 mg kg−1) and Fe (118–3884 mg kg−1) showed significant correlation (R = 0.54–0.74) via UBM, SBRC, and IVG, suggesting co-precipitation with Fe and/or sorption onto Fe oxides maybe responsible for decrease in Cd bioaccessibility. Although Cd bioaccessibility varied among assays, their results show some consistency based on their correlation in the GP (R = 0.56–0.90) and IP (0.34–0.73, excluding UBM-IP and PBET-IP). Sequential extraction data show that Cd was primarily associated with the exchangeable fraction (E1; 7.05–72.9%, averaging 39.4%). The carbonate (C2; 6.86–44.8%, 21.9%) and Fe/Mn oxides fraction (F3; 12.5–53.6%, 28.2%) were similar, while organic (O4; 0.62–25.0%, 7.91%) and residual fraction (R5; 0.22–8.54%, 2.62%) were the lowest. Significant correlation (R = 0.59–0.88) between the first two fractions (E1+C2) and bioaccessible Cd suggest they were the main sources of bioaccessible Cd in those contaminated soils.

To test high cadmium (Cd) concentration may not be high in health risk when considering Cd bioavailability, we assessed variation of Cd relative bioavailability (RBA, relative to CdCl2) using a mouse assay for 14 vegetables of water spinach, amaranth, and pakchoi. Cadmium concentration varied from 0.13 ± 0.01–0.37 ± 0.00 μg g–1 fw. Cadmium-RBA also varied significantly from 22.9 ± 2.12–77.2 ± 4.46%, however, the variation was overall opposite to that of Cd concentration, as indicated by a strong negative correlation between Cd-RBA and Cd concentration (R2 = 0.43). Based on both Cd concentration and bioavailability, the identified high-Cd pakchoi variety resulted in significantly lower Cd intake than the high-Cd varieties of water spinach and amaranth (4.74 ± 0.05 vs. 10.1 ± 0.54 and 8.03 ± 0.04 μg kg–1 bw week–1) due to significantly lower Cd-RBA (22.9 ± 2.12 vs. 77.2 ± 4.46 and 51.3 ± 2.93%). The lower Cd-RBA in pakchoi was due to its significantly higher Ca and lower phytate concentrations, which facilitated the role of Ca in inhibiting intestinal Cd absorption. This was ascertained by observation of decreased Cd-RBA (90.5 ± 12.0% to 63.5 ± 5.53%) for a water spinach when elevating its Ca concentration by 30% with foliar Ca application. Our results suggest that to assess food Cd risk, both total Cd and Cd bioavailability should be considered. Refereed/Peer-reviewed

Mushrooms accumulate arsenic (As), yet As concentrations, speciation, and localization in cultivated mushrooms across a large geographic distribution are unknown. We characterized 141 samples of nine species from markets in nine capital cities in China, with samples of Lentinula edodes, Pleurotus ostreatus, and Agaricus bisporus being analyzed for As speciation and localization. Total As concentrations ranged from 0.01 to 8.31 mg kg-1 dw, with A. bisporus (0.27-2.79 mg kg-1) containing the most As followed by P. ostreatus and L. edodes (0.04-8.31 and 0.12-2.58 mg kg-1). However, As in A. bisporus was mostly organic including nontoxic arsenobetaine, while P. ostreatus and L. edodes contained mainly inorganic As (iAs). On the basis of in situ imaging using LA-ICP-MS, As in L. edodes was localized to the surface coat of the cap, while As in P. ostreatus was localized to the junction of the pileus and stipe. When As speciation and daily mushroom consumption (1.37 g d-1 dw) are considered, daily mushroom consumption may result in elevated iAs exposure, with increased bladder and lung cancer rates up to 387 cases per 100000. Our study showed that market mushrooms could be a health risk to the general public so its production should be monitored. Refereed/Peer-reviewed

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous in the environment and some exhibit carcinogenic and mutagenic toxicity. Three methods have been used for identification of PAHs sources in so...

Cancerous human liver cell line has been used to test the hepatic toxicity of indoor dust, showing its organic extract decreases cell viability. However, little is known about its impact on normal human liver cell line. In the present study, we compared the cellular responses between carcinoma cell line (HepG2) and normal cell line (HL-7702) after exposing to 10-640 μg/100 μL organic dust extract for 24 h. The dust extract caused cytotoxicity, oxidative damage, inflammatory response and loss of mitochondrial transmembrane potential (MMP) in both cells. The inhibition of cell viability in HL-7702 cells was stronger than that in HepG2 cells, with HL-7702 cells having lower LC50. Higher production of oxidative stress, more loss of MMP and stronger suppression of antioxidant enzymes mRNA level occurred in HepG2 cells, while mRNA expression and hepcidin secretion were enhanced in HL-7702 cells at 40/100 μL, indicating the dust extract probably perturbed their liver Fe homeostasis. Our data showed considerable differences in cellular responses between normal and cancerous cell lines. To obtain accurate data, normal hepatocytes should be employed as they better match with the in vivo tissue than cancerous cell lines.

Arsenic contamination in drinking water is a worldwide issue, posing threat to human health. Arsenic is an endocrine system disruptor, however, limited information is available regarding its long-term effects on thyroid endocrine system at low exposure. In this study, we assessed the thyroid toxicity of arsenate (AsV) and arsenite (AsIII) at 10–100 μg L−1 in juvenile mice after 8-week of exposure via drinking water. After 1–2 week, AsV and AsIII had little influence on thyroxine (T4) level (56.3–64.7 μg L−1) in mouse blood compared to control mice at 57.3–60.7 μg L−1. However, after 4–8 weeks, 10 μg L−1 AsIII or AsV increased T4 levels to 83.8–88.8 μg L−1 compared to control treatment at 77.2–80.0 μg L−1, while 100 μg L−1 AsV or AsIII decreased T4 levels except for 100 μg L−1 AsIII for 8 weeks. Based on transmission electron microscopy, exposure to 100 μg L−1 AsIII or AsV for 8 weeks caused thyroid gland damage. In addition, exposure to AsV or AsIII at 10 or 100 μg L−1 impacted gene transcription of hypothalamic-pituitary-thyroid axis including thyroid stimulating hormone and iodothyronine deiodinases. Our data demonstrated that exposing to low levels of AsIII or AsV disrupted T4 homeostasis, influenced the related gene transcription and damaged the thyroid glands in juvenile mice.

Increasing studies have suggested that microRNAs (miRNAs) are involved in the development of gliomas. MicroRNA-216a has been reported to be a tumor-associated miRNA in many types of cancer, either as an oncogene or as a tumor suppressor. However, little is known about the function of miR-216a in gliomas. The present study was designed to explore the potential role of miR-216a in gliomas. We found that miR-216a was significantly decreased in glioma tissues and cell lines. Overexpression of miR-216a significantly suppressed the proliferation, migration, and invasion of glioma cells. Leucine-rich repeat-containing G protein-coupled receptor 5 (LGR5) was identified as a target gene of miR-216a in glioma cells by bioinformatics analysis, dual-luciferase reporter assay, real-time quantitative polymerase chain reaction, and Western blot analysis. Moreover, miR-216a overexpression inhibited the Wnt/β-catenin signaling pathway. The restoration of LGR5 expression markedly reversed the antitumor effect of miR-216a in glioma cells. Taken together, these findings suggest a tumor suppressor role for miR-216a in gliomas, which inhibits glioma cell proliferation, migration, and invasion by targeting LGR5. Our study suggests that miR-216a may serve as a potential therapeutic target for future glioma treatment.

Dietary Cd intake is often estimated without considering Cd bioavailability. Measured urinary Cd for a cohort of 119 nonsmokers with rice as a staple was compared to predicted values from rice-Cd intake with and without considering Cd relative bioavailability (RBA) in rice based on a steady state mouse kidney bioassay and toxicokinetic model. The geometric mean (GM) of urinary Cd and β 2 -microglobulin was 1.08 and 234 μg g -1 creatinine. Applying Cd-RBA in foods to aggregate Cd intake (41.5 ± 12.4, 48.0 ± 9.3, 48.8 ± 21.3% for rice, wheat, and vegetables), rice was the largest contributor (71%). For 63 participants providing paired urine and rice samples, the predicted GM of urinary Cd at 4.14 μg g -1 based on total Cd in rice was 3.5 times that of measured value at 1.20 μg g -1 , while incorporating Cd-RBA to assess rice-Cd intake made the two closer with GM at 1.07 μg g -1 . The cohort findings were extended to a national scale, with urinary Cd for nonsmokers from rice Cd intake was mapped at province/city levels after considering rice Cd-RBA. Therefore, incorporating Cd bioavailability to assess dietary Cd intake is a valuable tool to accurately estimate human Cd exposure and associated health risk. Refereed/Peer-reviewed

A steady-state mouse model was developed to determine arsenic (As) relative bioavailability (RBA) in rice to r efine As exposure in humans. Fifty-five rice samples from 15 provinces of China were analyzed for total As, with 11 cooked for As speciation and bioavailability assessment. Arsenic concentrations were 38-335 μg kg -1 , averaging 133 μg kg -1 , with As III being dominant (36-79%), followed by DMA V (18-58%) and As V (0.5-16%). Following oral doses of individual As species to mice at low As exposure (2.5-15 μg As per mouse) over a 7-d period, strong linear correlations (R 2 = 0.99) were observed between As urinary excretion and cumulative As intake, suggesting the suitability and sensitivity of the mouse bioassay to measure As-RBA in rice. Urinary excretion factor for DMA V (0.46) was less than inorganic As (0.63-0.69). As-RBA in cooked rice ranged from 13.2 ± 2.2% to 53.6 ± 11.1% (averaging 27.0 ± 12.2%) for DMA V and 26.2 ± 7.0% to 49.5 ± 4.7% (averaging 39.9 ± 8.3%) for inorganic As. Calculation of inorganic As intake based on total inorganic As in rice overestimated As exposure by 2.0-3.7 fold compared to that based on bioavailable inorganic As. For accurate assessment of the health risk associated with rice consumption, it is important to consider As bioavailability especially inorganic As in rice. Refereed/Peer-reviewed

Straw return is widely applied to increase soil fertility and soil organic carbon storage. However, its effect on N2O emissions from paddy soil and the associated microbial mechanisms are still unclear. In this study, wheat straw was amended to two paddy soils (2% w/w) from Taizhou (TZ) and Yixing (YX), China, which were flooded and incubated for 30 d. Real-time PCR and Illumina sequencing were used to characterize changes in denitrifying functional gene abundance and denitrifying bacterial communities. Compared to unamended controls, straw addition significantly decreased accumulated N2O emissions in both TZ (5071 to 96 mg kg–1) and YX (1501 to 112 mg kg–1). This was mainly due to reduced N2O production with decreased abundance of major genera of nirK and nirS-bacterial communities and reduced nirK and nirS gene abundances. Further analyses showed that nirK-, nirS- and nosZ-bacterial community composition shifted mainly along the easily oxidizable carbon (EOC) arrows following straw amendment among four different soil organic carbon fractions, suggesting that increased EOC was the main driver of alerted denitrifying bacterial community composition. This study revealed straw return suppressed N2O emission via altering denitrifying bacterial community compositions and highlighted the importance of EOC in controlling denitrifying bacterial communities.

Lead bioavailability in contaminated soils varies considerably depending on Pb speciation and sources of contamination. However, little information is available on bioavailability of Pb associated with different fractions. In this study, the Tessier sequential extraction was used to fractionate Pb in 3 contaminated soils to exchangeable (F1), carbonate-bound (F2), Fe/Mn oxides-bound (F3), organic-bound (F4), and residual fractions (F5). In addition, soil residues after F1–F2 extraction (F345), F1–F3 extraction (F45), and F1–F4 extraction (F5) were measured for Pb relative bioavailability (RBA) using a mouse kidney model. Based on the mouse model, Pb-RBA in the soils was 44–93%, which decreased to 43–89%, 28–75%, and 15–68% in the F345, F45, and F5 fractions, respectively. Based on Pb-RBA in the soil residues, Pb-RBA in different fractions was calculated based on a mass balance. The data showed that Pb-RBA was the highest (∼100%) in the exchangeable and carbonate fraction, and the lowest (15–68%) in the residual fraction. In addition, Pb in the first three fractions (F1–F3) contributed most (83–89%) to bioavailable Pb in contaminated soils. Our study shed light on oral bioavailability of Pb in contaminated soils of different fractions based on sequential extraction and provide important information for soil remediation.

Soils are often co-contaminated with As, Pb, and Cd. To what extent ingested metal(loid)s interact with each other in the gastrointestinal tract and influence their RBA (relative bioavailability) is largely unknown. Three soils predominantly contaminated with As (MS, mining/smelting impacted), Pb (WR, wire rope production impacted), and Cd (EP, enamel pottery production impacted) were administered to mice individually or in binary and tertiary combinations with sodium arsenate, Cd chloride, and/or Pb acetate. In binary combinations, 10-fold higher Pb addition decreased As-RBA in MS (26.0 ± 6.28% to 17.1 ± 1.08%), while 10-fold higher As addition decreased Pb-RBA in WR (61.3 ± 2.41% to 28.8 ± 5.45%). This was possibly due to the formation of insoluble Pb arsenate in mouse intestinal tract, as indicated by the formation of precipitates when As and Pb co-occurred in water or simulated human gastrointestinal fluids. Due to competition for shared absorption transporters, 10- A nd 100-fold higher Pb addition decreased Cd-RBA in EP (95.8 ± 12.9% to 67.8 ± 12.8% and 62.8 ± 8.24%). Tertiary combinations showed that interactions between two metal(loid)s were affected by the presence of the third metal(loid). Our study suggests that As oxyanion could interact with Pb or Cd ions in the mouse gastrointestinal tract, and the interactions vary depending on concentration and solution characteristics Refereed/Peer-reviewed

This study investigated the mechanisms through which arctigenin promotes osteogenesis. Bone marrow mesenchymal stem cells (BMSCs) from ovariectomized (OVX) rats were differentiated into osteoblasts, and osteogenesis was evaluated via Alizarin Red S (ARS) staining and alkaline phosphatase (ALP) measurements in cultured BMSCs. The levels of phosphorylated AKT serine/threonine kinase 1 (p-Akt), and peroxisome proliferator-activated receptor gamma (PPARγ) expression were quantified by Western blot analysis. The levels of urine calcium (U-Ca), urine phosphorus (U-P), serum ALP, and bone mineral density (BMD) of OVX rats were assessed in vivo. The results showed that treatment with arctigenin in rat BMSCs enhanced mineralization, increased ALP activity, increased the expression of Akt and p-Akt, and decreased PPARγ expression, consistent with its ability to promote osteoblast differentiation. Furthermore, arctigenin prevented OVX-induced osteoporosis in rats by increasing BMD and ALP activity and inhibiting the loss of Ca and P. In contrast, treatment with LY294002, a selective inhibitor of the phosphatidylinositol 3-kinase (PI3K), produced the opposite phenotype. These data suggest that the protective effects of arctigenin on BMSCs and OVX rat models result from the induction of osteogenesis involving the PI3K/Akt/PPARγ axis.

The robustness of in vitro bioaccessibility assays to predict oral relative bioavailability (RBA) of multiple metals in contaminated soils requires validation using additional soil samples. In this study, 11 contaminated soils from mining/smelting areas were analyzed for As-, Cd-, and Pb-RBA using a mouse bioassay and metal bioaccessibility via the UBM gastric phase assay. Metal-RBA varied considerably among soils, with As-RBA (2.5–23%, mean 12%) being generally lower than Cd-and Pb-RBA (3.4–88 and 3.3–59%, mean 42 and 28%), due to higher proportions of As in the residual fractions. Metal-RBA generally decreased with increasing metal concentrations probably due to reduced labile metal fractions. In addition, strong negative correlations were observed between total Fe with As-, Cd-, and Pb-RBA (R2 = 0.46–0.77), suggesting the role of Fe in controlling metal-RBA in soils. Like RBA, metal bioaccessibility by the UBM assay also varied among samples. However, strong in vivo-in vitro correlations (IVIVCs) were observed between metal-RBA and bioaccessibility (R2 = 0.52–0.81). Further, there were little differences when As-, Cd-, and Pb-IVIVCs established using soils from this study and soils pooled from literature were compared, suggesting the robustness of the UBM assay to predict metal-RBA in contaminated soils. Keywords: Heavy metals, Mouse model, Bioavailability, In vitro assay, Bioaccessibility

Organoarsenicals have been used in poultry production for years, however, studies focused on roxarsone (ROX), with little attention to p-arsanilic acid (ASA). We assessed arsenic (As) concentration and speciation in chicken meat collected from 10 cities in China. The geometric mean for total As in 249 paired raw and cooked samples was 4.85 and 7.27 μg kg–1 fw, respectively. Among 81 paired raw and cooked samples, ASA and ROX were detected in >90% samples, suggesting the prevalence of organoarsenical use in China. ASA contributed the most (45% on average) to total As in cooked samples, followed by As(V), DMA, As(III), and ROX (7.2–22%). ASA was found to contribute more to total As in chicken meat compared to ROX for the first time. Arsenic in chicken meat showed considerable geographic variation, with higher inorganic arsenic (iAs) being detected from cities with higher ROX and ASA, indicating that organoarsenical use increased iAs concentration in chicken meat. When health risk was estimated, dietary exposure to iAs would result in an increase of 3.2 bladder and lung cancer cases per 100,000 adults. The result supports the removal of organoarsenicals in poultry production from Chinese market and further supports its removal from the global markets. Refereed/Peer-reviewed

Fully bio-based polyamide 1010 (PA1010) was successfully melt-blended with poly (vinyl alcohol) (PVA03, PVA05, PVA08 and PVA14) to prepare PA1010xPVAzy blends. The PA1010xPVA03y, PA1010xPVA05y, PA1010xPVA08y and PA1010xPVA14y films demonstrated the lowest oxygen transmission rates (OTR), free volume fraction (Fv), mean volume of the free volume holes (Vf) and mean number of free volume holes per unit volume (I3) values, when the PVA concentration in each PA1010xPVAzy series reached a corresponding critical value of 22.5, 20, 17.5 and 12.5 wt%, respectively. OTR, Fv, Vf and I3 values obtained for the best PA101087.5PVA1412.5, PA101082.5PVA0817.5, PA101080PVA0520 and PA101077.5PVA032.25 films reduced gradually as the degree of polymerization of PVA reduced. The results of dynamical mechanical and other experimental characterizations demonstrated that PA1010 and PVA are compatible to some extent, when the PVA are ≤ the corresponding critical concentration. The significantly enhanced oxygen permeation resistance and free volume characteristics for optimal PA1010xPVAzy films is at least partly due to the improved hydrogen-bonded molecular interactions between PA1010 C=O groups and PVA O-H groups.

Although strong in vivo-in vitro correlations (IVIVCs) between relative bioavailability (RBA) and bioaccessibility of soil Pb were well reported, knowledge on the fractions of bioaccessible Pb in simulated gastrointestinal (GI) fluids that are available for absorption into the systemic circulation is limited. Here, Pb-RBA in 14 Pb-contaminated soils were assessed using an in vivo mouse bioassay and compared to Pb bioaccessibility by the gastrointestinal phase of the UBM (Unified Bioaccessibility research group of Europe (BARGE) Method) in vitro assay with and without 0.45 μm filtration of GI fluid. Results showed good IVIVC between Pb-RBA and Pb bioaccessibility without filtration ( r 2 = 0.62), while Pb bioaccessibility with filtration provided a poor correlation with Pb-RBA ( r 2 = 0.16). This suggested that besides dissolved Pb ions, Pb-complexes formed in the UBM gastrointestinal fluid might also contribute to bioavailable Pb. To ascertain this, DGT (diffusive gradients in thin-films) devices which can measure both Pb2+ ions and labile inorganic and organic Pb-complexes were introduced to the UBM fluids to measure Pb DGT-bioaccessibility, which showed strong correlation to Pb-RBA ( r 2 = 0.71). With increasing diffusive gel thickness which could enhance release of Pb ions from Pb-complexes, Pb DGT-bioaccessibility increased by 3.4-5.7 times, while inclusion of dialysis membrane within DGT devices significantly decreased Pb DGT-bioaccessibility by inhibiting diffusion of Pb complexes to binding gel. These results confirmed the contribution of Pb-complexes to Pb bioavailability, providing new insights to Pb bioavailability.

Due to its toxicity as a carcinogen and wide distribution in the environment, arsenic (As) exposure in humans is of public concern globally. Many studies have manifested that As exposure induces cancers besides pathological effects in humans. Animal studies showed that chronic As exposure induces serious neurological effects. Based on recent studies, researchers proposed that As, including arsenate (AsV) and arsenite (AsIII), is also an endocrine disruptor. This review discusses the mechanisms of As toxicity on three endocrine systems including gonadal, adrenal and thyroid endocrine systems. Arsenic methylation and oxidative stress are responsible for As-induced disorders of endocrine systems, however, strong binding of AsIII to thiols also play an important role. Some studies showed AsV toxicity on endocrine systems, but mechanistic investigation is lacking. Research is needed to look into their toxicity mechanisms to help cure the illnesses caused by As-induced endocrine system disorders. Keywords: Arsenite, Arsenate, Endocrine disruptor, Hypothalamic-pituitary-gonadal axis, Hypothalamic-pituitary-adrenal axis, Hypothalamic-pituitary-thyroid axis

In vitro assays have been developed to determine metal bioaccessibility in contaminated soils; however, their application to Cd is limited. To assess their suitability to determine Cd relative bioavailability (RBA), Cd-RBA in 12 contaminated soils containing 3.00–296 mg kg−1 Cd were determined using a mouse model and compared with Cd bioaccessibility data based on four assays including the UBM, SBRC, IVG, and PBET. After being administered feed amended with soil or CdCl2 for 10-day, the Cd concentrations in the mouse liver and/or kidneys were used as biomarkers to estimate Cd-RBA. Cd-RBA was comparable at 34–90% and 40–78% based on mouse liver and kidneys with RSD of 7.10–8.99%, and 37–84% based on mouse liver plus kidneys with lower RSD of 5.8%. Cadmium bioaccessibility in soils varied with assays, with 61–99, 59–103, 54–107, and 35–97% in the gastric phase and 20–56, 38–77, 42–88, and 19–64% in the intestinal phase of the UBM, SBRC, IVG and PBET assays. Based on the combined biomarker of liver plus kidneys, better correlation was observed for PBET (r2 = 0.61–0.70) than those for IVG, UBM and SBRC assays (0.12–0.52). The monthly Cd intake in children was 0.24–23.9 μg kg−1 using total Cd concentration in soils, which was reduced by 43% to 0.18–12.3 μg kg−1 using bioavailable Cd. Our data suggest it is important to consider Cd-RBA to assess risk associated with contaminated soils and the PBET may have potential to predict Cd-RBA in contaminated soils. Keywords: Bioavailability, Heavy metal, Kidneys, Liver, Biomarker, Contamination

3-Amino-4,4'-bi-1,2,4-triazole hydrochlorate and 3,3'-diamino-4,4'-bi-1,2,4-triazole ditosylate were obtained with the reduction of 3,3',5,5'-tetraazide-4,4'-bi-1,2,4-triazole (TABT) by (Ph)3P/H2O and the followed salt forming reaction with concentrated HCl and aqueous TsOH, respectively. Their structures were characterized with elemental analyses, IR, MS, 1H and 13C NMR spectra. The single crystals were cultivated and determined with X-ray diffraction, test results reveal that H+ combines with electron-rich N atom in triazole ring to form ionic salts, two N,N-linked triazoles are almost perpendicular to each other due to lower steric hindrance. The aromatic π…π stacking interactions and hydrogen bonds between molecules are observed. These two novel salts and their derivatives may be applied in coordination chemistry, medicinal chemistry and energetic materials.

Recent studies have investigated lead (Pb) concentrations in lip products but little is known about its oral bioavailability. In this study, 75 lipsticks and 18 lip glosses were assessed for Pb concentration, while 15 samples were assessed for Pb relative bioavailability (RBA, relative to Pb acetate absorption) using a mouse femur assay. Lead concentrations were 0.2-10 185 mg kg(-1), with 21 samples exceeding the Chinese limit of 40 mg kg(-1). Samples with orange and pink colors and/or low cost contained higher Pb concentrations. For samples with Pb > 7500 mg kg(-1), Pb was present due to the addition of lead chromate (PbCrO4) as a colorant, which was confirmed by X-ray absorption near-edge structure analysis. Lead RBA in 15 samples (87-10 185 mg kg(-1)) ranged from 23% to 95%, being significantly higher in moderate Pb (56-95%; 87-300 mg kg(-1)) than high Pb samples (23-48%; >300 mg kg(-1)). The calculation of Pb intake based on Pb-RBA showed that lip product ingestion contributed 5.4-68% of the aggregate Pb exposure for women depending on Pb concentration. The high Pb concentration in some lip products together with their moderate Pb-RBA suggests that lip product ingestion is a potential health concern to women. Refereed/Peer-reviewed

Despite high morbidity and mortality, no effective options are available for the treatment of acute lung injury (ALI). Therefore, the present study investigated the protective effect of honokiol (HK) on ALI via determination of its effect on several key biomarkers. The results of the study showed that HK significantly inhibited the infiltration of neutrophils and protein leakage induced by lipopolysaccharide (LPS) (p

Arsenic-hyperaccumulator Pteris vittata is efficient in As absorption, reduction, and translocation. But the molecular mechanisms and locations of arsenate (AsV) reduction in P. vittata are still unclear. Here, we identified two new arsenate reductase genes from P. vittata, PvHAC1 and PvHAC2. Two PvHAC genes encoded a rhodanase-like protein, which were localized in the cytoplasm and nucleus. Both recombinant Escherichia coli strains and transgenic Arabidopsis thaliana lines showed arsenate reductase ability after expressing PvHAC genes. Further, expressing PvHAC2 enhanced As tolerance and reduced As accumulation in A. thaliana shoots under AsV exposure. Based on expression pattern analysis, PvHAC1 and PvHAC2 were predominantly expressed in the rhizomes and fronds of P. vittata. Different from those of HAC homologous genes in non-hyperaccumulators, little PvHAC was expressed in the roots. Besides, PvHAC1 expression was strongly upregulated under AsV exposure but not AsIII. The data suggest that arsenate reductase PvHAC1 in the rhizomes coupled with arsenate reductase PvHAC2 in the fronds of P. vittata played a critical role in As-hyperaccumulation by P. vittata, which helps to further improve its utility in phytoremediation of As-contaminated soils.

Arsenic (As) and cadmium (Cd) are ubiquitous in the environment and they are both toxic to humans. When present in soils, they can enter food chain, thereby threatening human health. Water spinach (Ipomoea aquatica) is an important leafy vegetable, which is widely consumed in Asian countries. However, it is efficient in taking up As and Cd from soils and accumulating them in the edible parts. Therefore, it is of significance to reduce its As and Cd content, especially in contaminated soil. In this study, pot experiments were conducted to investigate the ability of As-hyperaccumulator Pteris vittata in reducing As and Cd uptake by water spinach under different phosphorus treatments. P. vittata was grown for 60 d in a contaminated-soil amended with P fertilizer (+P) or phosphate rock (+PR), followed by water spinach cultivation for another 30 d. Plant biomass, As and Cd contents in plants and soils, and soil pH were analyzed. We found that, P. vittata coupled with PR decreased the As concentration in water spinach shoots by 42%, probably due to As uptake by P. vittata. Moreover, P. vittata decreased the Cd accumulation in water spinach by 24–44%, probably due to pH increase of 0.47–0.61 after P. vittata cultivation. Taking together, the results showed that P. vittata coupled with PR decreased the As and Cd content in water spinach, which is of significance for improving food safety and protecting human health.

Breed improvement is an important genetic process affecting meat quality. Compared with Kazakh cattle, Xinjiang brown cattle have significantly improved carcass quality and meat quality. To elucidate the molecular mechanisms underlying the improvements in Xinjiang brown cattle and the differences in beef quality between the two breeds, we used RNA-Seq to study differentially expressed genes and miRNAs and regulatory pathways related to adipogenesis, myogenesis and fibrogenesis in the longissimus dorsi muscles of Xinjiang brown cattle and Kazakh cattle. The results showed that 1669 genes were differentially expressed in the longissimus dorsi muscle tissues of Xinjiang brown cattle and Kazakh cattle; 879 genes were upregulated and 790 genes were downregulated in Xinjiang brown cattle compared to Kazakh cattle. These genes were mainly involved in PPAR signaling, unsaturated fatty acid biosynthesis and vascular smooth muscle contraction. Additionally, 346 differentially expressed miRNAs were identified, of which 265 miRNAs were downregulated and 81 miRNAs were upregulated in Xinjiang brown cattle compared to Kazakh cattle. Association analysis of the differentially expressed genes and miRNAs revealed that 86 differentially expressed miRNAs related to adipogenesis were associated with 31 differentially expressed genes, 76 differentially expressed miRNAs associated with myogenesis were associated with 28 differentially expressed genes, and 54 differentially expressed miRNAs associated with fibrogenesis were associated with 19 differentially expressed genes. miRNA-target gene networks were also constructed. Finally, the expression levels of 19 genes and miRNAs were verified by qRT-PCR. Some differentially expressed genes, including FABP4, ACTA2 and ACTG2, were shown to play an important role in beef meat quality. This is the first study to perform transcriptomic analysis of muscle tissues from Xinjiang brown and Kazakh cattle.

In this study, the predominant Pb minerals prior to and after Pb relative bioavailability (Pb-RBA) and Pb bioaccessibility (Pb-BAc) tests were identified using SEM (scanning electron microscopy), XANES (X-ray absorption near edge structure) and XRD (X-ray diffraction). The correlations between in vitro Pb-BAc (using the UBM (Unified BARGE Method) and RBALP (Relative BioAccessibility Leaching Procedure) models) and in vivo Pb-RBA (using endpoints of kidney and liver in an mice model) were determined. The results demonstrated that both RBALP and UBM (gastric phase) reliably indicate Pb-RBA (Pb-RBA). However, raising the solid:liquid ratio of the gastric phase of UBM is necessary to determine Pb-BAc if the soils contain total Pb >10,000 mg/kg. The comparison of Pb minerals prior to and after in vitro extractions demonstrated that the relatively soluble forms of Pb (PbSO4, PbO2 and MgO Pb) start to dissolve than other forms of Pb minerals, suggesting there was no difference in Pb2+ release between chemical-based (RBALP) and physiologically-based (UBM) models. The identification of the Pb minerals of Pb5(PO4)3Cl and organically-complexed Pb in mice excreta demonstrated that a portion of Pb2+ combined with food and humic acid to generate organically-complexed Pb in mice excreta, and that Pb5(PO4)3Cl is not bioavailable.

Oxygen transmission rates and free volume properties (i.e. average volumes of free-volume-cavities (Vf), mean number of the free volume cavities per unit volume (I3) and fractional free volume (Fv)) values of bio-based polyamide 612 (PA612)/poly(vinyl alcohol) (PVA) (i.e. PA612xPVA03y, PA612xPVA05y, PA612xPVA08y and PA612xPVA14y) blend films were reduced to a minimum value, when their PVA content reached corresponding optimal values of 25, 20, 15 and 10 wt%, respectively. The minimum oxygen transmission rate, Vf, I3 and Fv value obtained for the best PA61290PVA1410, PA61285PVA0815, PA61280PVA0520 and PA61275PVA0325 bio-based blown films reduced considerably with decreasing PVA degrees of polymerization. As evidenced by the results of dynamical mechanical analysis, differential scanning calorimetry, wide angle X-ray diffraction and Fourier transform infrared spectroscopic experiments, PA612 and PVA are miscible to some extent at the molecular level when their PVA contents are ≤ the corresponding optimal values. The significantly improved oxygen barrier and free volume properties for the PA612xPVAzy blend films with optimized compositions is at least in part to the enhanced intermolecular interactions between PA612 carbonyl groups and PVA hydroxyl groups.

When considering human exposure to arsenic (As), lead (Pb), and cadmium (Cd) via incidental soil ingestion, daily intake is greatly influenced by their bioavailability (i.e., the proportion of metals that are absorbed into the systemic circulation). Animal models have been used to estimate heavy metal relative bioavailability (RBA; relative to the adsorption of soluble references). However, there is a lack of comparison among different in vivo assays, which may bring uncertainty when assessing the risks with soil ingestion. In addition, to overcome the time, cost, and ethical limits of in vivo assays, in vitro bioaccessibility assays have been developed to determine the amount of metal extracted from soil matrix in simulated human gastric and intestinal fluid. However, to determine if these assays provide a good prediction of RBA, it is important to establish in vivo–in vitro correlations. In this chapter, we talked about in vivo and in vitro assays that have been used to determine bioavailability of metals in soils, focusing on comparison of As-RBA in soils between different animal models and the ability of in vitro assays to predict RBA of metals. Based on 12 As-contaminated soils, it was demonstrated that different animals, dosing approaches, and biomarkers had little impact on the outcome of in vivo assays. Based on each 12 As-, Pb-, and Cd-contaminated soils from China, the gastric phase (GP) of in vitro UBM and SBRC assay was best correlated with Pb-RBA among different in vitro assays, while IVG-GP and PBET-GP showed strongest correlation with As-RBA and Cd-RBA, suggesting in vitro assays have potential to predict heavy metals RBA in contaminated soils. To accurately assess the health risks and establish cleanup standard of contaminated soils, bioavailability of metals should be considered.

Both dietary and non-dietary pathways contribute to metal exposure in residents living near mining-impacted areas. In this study, bioavailability-based metal intake estimation coupled with stable Pb isotope ratio fingerprinting technique were used to discern dietary (i.e., rice consumption) and non-dietary (i.e., housedust ingestion) contribution to As, Cd, and Pb exposure in residents living near mining-impacted areas. Results showed that not only rice (n = 44; 0.10–0.56, 0.01–1.77, and 0.03–0.88 mg kg−1) but also housedust (n = 44; 2.15–2380, 2.55–329, and 87.0–56,184 mg kg−1) were contaminated with As, Cd, and Pb. Based on in vivo mouse bioassays, bioavailability of As, Cd, and Pb in rice (n = 11; 34 ± 15, 59 ± 13, and 31 ± 15%) were greater than housedust (n = 14; 17 ± 6.7, 46 ± 10, and 25 ± 6.8%). Estimated daily intake of As, Cd, and Pb after incorporating metal bioavailability showed that As intake via rice was 5-fold higher than housedust for adults, whereas As intake via housedust was 3-fold higher than rice for children. For both adults and children, rice was the main source for Cd exposure, while housedust was the predominant Pb contributor. To ascertain the dominant Pb source from housedust ingestion, stable Pb isotope ratios (207Pb/206Pb and 208Pb/206Pb) of hair samples of local residents (n = 27, 0.8481 ± 0.0049 and 2.0904 ± 0.0102) were compared to housedust (n = 27, 0.8485 ± 0.0047 and 2.0885 ± 0.0107) and rice (n = 27, 0.8369 ± 0.0057 and 2.0521 ± 0.0119), showing an overlap between hair and housedust, but not rice, confirming that incidental housedust ingestion was the main source of Pb exposure. This study coupled bioavailability and stable isotope techniques to accurately identify the source of metal exposure as well as their potential health risk. Keywords: As, Cd, Pb, Rice, Housedust, Risk assessment

Paints are often used on chopsticks, however, a paucity of studies has assessed metals in the paints and the associated health risk. In this study, total Pb, Cd, Cr, Co, and Ni concentrations in paints were assessed for 72 wood and 29 stainless steel chopsticks with different colors while metal solubilization from paints in simulated saliva, 0.07M HCl, and 1% citric acid solutions was measured for 9 samples having total Pb> 90 mg kg⁻¹,representing exposure scenarios of mouthing, incidental paint ingestion, and metal migration in food. Results showed that Pb (0.12–500,000 mg kg⁻¹), Cd (0.002–120,000 mg kg⁻¹), Cr (2.2–8400 mg kg⁻¹), Co(0.004–2600 mg kg⁻¹), and Ni (0.10–150,000 mg kg⁻¹) concentrations varied considerably among paint samples.Most samples showed low metal concentrations, however, high metal concentrations were observed in red and green paints on stainless steel chopsticks, while paints on wood chopsticks showed lower metal concentrations.Estimation of daily metal intakes incorporating metal solubilization data in saliva, 0.07M HCl, and 1% citric acid solutions suggested that the health risk via saliva contact was negligible, while unacceptable health risk was observed for Pb and Cd via their solubilization in 0.07M HCl and 1% citric acid solutions from paints with high Pb and Cd concentrations. To avoid Pb and Cd exposure, use of metal-based paints on chopsticks should be banned, particularly in countries where food is regularly consumed with chopsticks. Refereed/Peer-reviewed

Two novel tetrahalogeno-4,4′-bi-1,2,4-triazoles, tetrachloro-4,4′-bi-1,2,4-triazole (1, TCBTr) and tetrabromo-4,4′-bi-1,2,4-triazole (2, TBBTr) were successfully synthesized through halogenation of 4,4′-bi-1,2,4-triazole (BTr) and structurally characterized by elemental analysis, IR, 13C NMR and MS spectra. The single crystals of title compounds were cultivated and determined with X-ray diffraction, and the test results reveal that the aromatic π…π stacking interactions between molecules and the tetrahalogeno-4,4′-bi-1,2,4-triazoles with the two triazole rings being perpendicular are well observed in the crystal structure of (1) and (2).

Different animals and biomarkers have been used to measure the relative bioavailability of arsenic (As-RBA) in contaminated soils. However, there is a lack of As-RBA comparison based on different animals (i.e., swine and mouse) and biomarkers [area under blood As concentration curve (AUC) after a single gavaged dose vs steady-state As urinary excretion (SSUE) and As accumulation in liver or kidney after multiple doses via diet]. In this study, As-RBA in 12 As-contaminated soils with known As-RBA via swine blood AUC model were measured by mouse blood AUC, SSUE, and liver and kidney analyses. As-RBA ranges for the four mouse assays were 2.8-61%, 3.6-64%, 3.9-74%, and 3.4-61%. Compared to swine blood AUC assay (7.0-81%), though well correlated (R2 = 0.83), the mouse blood AUC assay yielded lower values (2.8-61%). Similarly, strong correlations of As-RBA were observed between mouse blood AUC and mouse SSUE (R2 = 0.86) and between urine, liver, and kidney (R2 = 0.75-0.89), suggesting As-RBA was congruent among different animals and end points. Different animals and biomarkers had little impact on the outcome of in vivo assays to validate in vitro assays. On the basis of its simplicity, mouse liver or kidney assay following repeated doses of soil-amended diet is recommended for future As-RBA studies. Refereed/Peer-reviewed

Previous studies have established in vivo-in vitro correlations (IVIVC) between arsenic (As) relative bioavailability (RBA) and bioaccessibility in contaminated soils. However, their ability to predict As-RBA in soils outside the models is unclear. In this study, As bioaccessibility and As-RBA in 12 As-contaminated soils (22.2-4172 mg kg(-1) As) were measured using five assays (SBRC, IVG, DIN, PBET, and UBM) and a mouse blood model. Arsenic RBA in the soils ranged from 6.38 ± 2.80% to 73.1 ± 17.7% with soils containing higher extractable Fe showing lower values. Arsenic bioaccessibility varied within and between assays. Arsenic bioaccessibility was used as input values into established IVIVC to predict As-RBA in soils. There were significant differences between predicted and measured As-RBA for the 12 soils, illustrating the inability of established IVIVC to predict As-RBA in those contaminated soils. Therefore, a new IVIVC was established by correlating measured As-RBA and As bioaccessibility for the 12 soils. The strength of the predictive models varied from r(2) = 0.50 for PBET to r(2) = 0.83 for IVG, with IVG assay providing the best prediction of As-RBA. When IVIVC were compared to those of Juhasz et al. (2014a), slopes of the relationships were significantly higher possibly due to different As-RBA measurements. Our research showed that IVG has potential to measure As bioavailability in contaminated soils from China though UBM and SBRC assays were also suitable. More research is needed to verify their suitability to predict As-RBA in soils for refining health risk assessment.

We compared four methods to extract arsenic (As) from three different plants containing different As levels for As speciation with the goal of developing a more efficient method, i.e., As-hyperaccumulator Pteris vittata at 459-7714mgkg(-1), rice seedling at 53.4-574mgkg(-1), and tobacco leaf at 0.32-0.35mgkg(-1). The four methods included heating with dilute HNO3, and sonication with phosphate buffered solution, methanol/water, and ethanol/water, with As being analyzed using high-performance liquid chromatography coupled with inductively-coupled plasma mass spectrometry (HPLC-ICP-MS). Among the four methods, the ethanol/water method produced the most satisfactory extraction efficiency (~80% for the roots and >85% for the fronds) without changing As species based on P. vittata. The lower extraction efficiency from P. vittata roots was attributed to its dominance by arsenate (82%) while arsenite dominated in the fronds (89%). The ethanol/water method used sample:solution ratio of 1:200 (0.05g:10mL) with 50% ethanol and 2h sonication. Based on different extraction times (0.5-2h), ethanol concentrations (25-100%) and sample:solution ratios (1:50-1:300), the optimized ethanol/water method used less ethanol (25%) and time (0.5h for the fronds and 2h for the roots). Satisfactory extraction was also obtained for tobacco leaf (78-92%) and rice seedlings (~70%) using the optimized method, which was better than the other three methods. Based on satisfactory extraction efficiency with little change in As species during extraction from three plants containing different As levels, the optimized method has the potential to be used for As speciation in other plants.

The polishing process was optimized according to the polishing rate and its consistency of HE slurry with different dilution multiple on the copper wafers, it can be confirmed that: the best pressure value of HE1, HE10, HE20, HE50 type slurries was 6890Pa, the best flow rate value of the preceding three slurries was 300ml/min, the best value of the HE50 slurry was 400ml/min. Through the planarization effects of the slurries with different dilution multiple, it can be obtained that: the initial dishing and erosion heights of the samples were both 1270nm and -500nm, and the two values respectively changed to 539.3nm, -75.7nm and 796.3nm, -191.3nm after being treated by HE1 and HE10 slurries, the step height of the wafer changed from 117nm to 72nm after being treated by HE20 slurry, the step height of the wafer changed from 88nm to 71nm after being treated by HE50 slurry. It was concluded that: the HE slurry shows strong ability for step removal when the slurry is diluted by 1 times and 10 times, the HE slurry also owns high planarization ability when the slurry is diluted by 20 times and 50 times.

Anode electrogenic bacteria (AEB) widely exist in paddy soils and play an important role in element biogeochemical cycling. However, little information is available on the role of soil characteristics in shaping AEB community. Therefore, the objective of this study was to evaluate the role of soil properties in driving the evolution of anode bacterial communities. Microbial fuel cells (MFCs) were constructed for five paddy soils with different chemical properties. The bacterial communities at anodes of closed (MFC running) and open (control) circuit MFCs were characterized using 16S rRNA gene-based Illumina sequencing. Paddy soils with higher dissolved organic carbon (DOC) and ammonium (NH4 +) concentrations in porewater showed higher MFC performance. Without MFC running, the dominant bacterial community composition was similar among the used five soils with Clostridia as the dominant bacteria at class level. Compared to control treatments, MFC running significantly decreased bacterial diversity and altered the bacterial community composition at anodes. However, the shift of bacterial communities varied with different types of soils. Betaproteobacteria was enriched by 4–30 times after MFC running for low MFC performance soils, while Deltaproteobacteria enriched (4–20 times) for high MFC performance soils. Redundancy analysis (RDA) indicated that DOC, NH4 +, and dissolved ferrous (Fe2+) significantly shift anode bacterial communities for the five soils with MFC running. We found that high-performing MFCs constructed from paddy soils with high DOC and NH4 + concentrations in porewater selected for an active, highly electrogenic bacterial community (dominated by Deltaproteobacteria) at anodes, while the dominant bacterial community for the low-performing MFCs from soils with low DOC and NH4 + was Betaproteobacteria. These findings imply that soil properties shape the AEB composition, therefore influencing MFC performance. This study provides new insights into the microbial-mediated carbon and nitrogen cycling in paddy soils.

A simple and efficient strategy for the synthesis of novel aryloxy-functionalised 4,4′-bi-1,2,4-triazoles was successfully explored by nucleophilic aromatic substitution of tetrachloro-4,4′-bi-1,2,4-triazole by various phenols using Cs2CO3 as catalyst. The syntheses were achieved in 25–94% yields.