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In this study, the distribution of precious metals in waste printed circuit boards was investigated and the economic value of recycling was assessed. Contacts of pins, slots, interfaces and the board surface in waste printed circuit boards were analyzed, and three types of precious metals were detected. The content of gold, silver and palladium ranged from 179.86 mg/kg to 3694.51 mg/kg, 809 mg/kg to 12320.51 mg/kg and 96.25 mg/kg to 117.49 mg/kg, respectively. Gold was distributed wildly in contacts of many slots and all interfaces, while contacts of only two interfaces (the cable and USB) contained palladium. The highest content of Au was found in contacts of the cable. Silver mainly concentrated on pins (metal foil contacts) of electronic components and its highest content was found in microchips. The economic value of recyclable precious metals in 1 t waste printed circuit boards was up to 2292.94 dollars, of which Au contributed 98%. This study indicates the prominent economic benefits of precious metal recovery from waste printed circuit boards. Moreover, the scientific information provide guidance for the directional and accurate recovery of precious metals from waste printed circuit boards.

Neonicotinoids (NEOs) are insecticides that are widely used around the world. Following exposure, NEOs get metabolized in human bodies. The biomarkers to assess human NEO exposure are not well described because of the lack of information on the metabolites of NEOs (m-NEOs). In this study, five m-NEOs including N-desmethyl-acetamiprid (N-dm-ACE), 5-hydroxy-imidacloprid (5-OH-IMI), olefin-imidacloprid (Of-IMI), 1-methyl-3-(tetrahydro-3-furylmethyl) guanidine (DIN-G), and 1-methyl-3-(tetrahydro-3-furylmethyl) (DIN-U) were measured in 275 urine samples collected from 10 cities in China. All of the m-NEOs were frequently detected in urine samples with the median concentrations ranging from 0.42 (DIN-G) to 1.02 (5-OH-IMI) ng/mL. The urinary concentrations of N-dm-ACE and 5-OH-IMI measured in China were higher than those reported from Japan and the USA. In comparison to the parent NEO (i.e., acetamiprid, ACE; imidacloprid, IMI; and dinotefuran, DIN) concentrations reported in the same set of samples by our research group, the median ratios of m-NEO to the corresponding parent NEO (m-NEO/NEO) ranged from 4.95 (DIN-G/DIN) to 37.7 (N-dm-ACE/ACE), indicating that NEOs are mainly present as metabolites rather than the parent forms. Furthermore, the ratio of Σm-NEOs/ΣNEOs was significantly (p < 0.01) higher in females than in males, suggesting that NEOs are more readily metabolized in females or females are more highly exposed to m-NEOs. To our knowledge, this is the first study to measure Of-IMI, DIN-G, and DIN-U levels in urine samples from China. We recommend biomonitoring studies to include N-dm-ACE, 5-OH-IMI, and DIN-U (and DIN-G) for clear understanding of human exposure to ACE, IMI, and DIN, respectively.

The elimination of volatile organic compounds (VOCs) via vacuum ultraviolet (VUV) photolysis is greatly limited by low removal efficiency and gaseous byproducts generation, while photocatalytic oxidation of VOCs suffers from catalytic deactivation. Herein, a coupled process of gaseous VUV photolysis with aqueous photocatalytic oxidation with P25 as the catalyst was firstly proposed for efficient aromatic VOCs removal (VUV/P25). The removal efficiency of toluene reached 86.2% in VUV/P25 process, but was only 33.6% and 58.1% in alone gaseous VUV photolysis and aqueous ultraviolet photocatalytic oxidation (UV/P25) process, respectively. Correspondingly, the outlet CO

As a kind of emerging pollutant, volatile organic compounds (VOCs) are getting increasing attention due to their contribution to the formation of atmospheric haze and O

Hierarchically porous molybdenum trioxide (MoO3) electrocatalyst is controllably synthesized by the facile hydrothermal method with the assistance of soft template (polyethylene oxide-polypropylene oxide-polyethylene oxide, P123). The as-prepared porous MoO3 material works as a highly efficient and bifunctional electrocatalyst for oxygen and hydrogen evolution. In oxygen evolution reaction (OER), the porous MoO3 electrode shows an overpotential reduction of 52 mV compared with precious RuO2, which is also superior to that of commercial MoO3. Besides, the electrochemical active surface area (ECSA) of porous MoO3 (2.8 cm2) which is three times higher than that of commercial MoO3 (0.8 cm2). For hydrogen evolution reaction (HER), porous MoO3 electrode exhibits a reduction of 113 mV overpotential at −10 mA cm−2 compared with commercial MoO3. Furthermore, the ECSA value of porous MoO3 (1.4 cm2) is four times higher than that of commercial MoO3 (0.3 cm2). The bifunctional MoO3 material displays Tafel slopes of 0.44 and 0.75 times for OER and HER than those of commercial MoO3. Besides, bifunctional MoO3 material exhibits high durability for both reactions in 24 h.

Phthalate esters (PAEs) can be released into the environment during the dismantling of electronic waste (e-waste), but urinary levels of PAE metabolites (mPAEs) in humans living in e-waste sites have not been documented. In this study, 11 mPAEs were determined in urine samples collected from participants living in e-waste dismantling sites and a reference area in Southern China. The total urinary concentrations of the 11 mPAEs (∑mPAEs) in the e-waste sites (range: 11.1 ng/mL to 3380 ng/mL) were dominated by mono-(2-isobutyl) phthalate and mono-n-butyl phthalate. Participants living in the e-waste sites had significantly higher (p

The elderly people living near electronic waste (e-waste) dismantling sites are susceptible to elevated chemical exposure, which is acerbated by hypometabolism and diminished immune tolerance. In this study, paired serum and urine samples collected from 1025 elderly people (≥60 years old) living near e-waste dismantling sites (n = 800) and reference areas (n = 225) in South China were analyzed for markers of health status and chemical exposures. Our results indicated that among all the health indicators fasting blood glucose (FBG) and urinary clinical markers were significantly higher in e-waste areas than in the reference area. Sixteen legacy perfluoroalkyl substances (PFASs) were determined in serum samples of elderly individuals living near e-waste dismantling areas (n = 171) and a reference area (n = 50). Serum PFASs concentrations in individuals from e-waste dismantling areas were significantly higher (p < 0.05) than those from the reference area, which indicated that e-waste dismantling activities a...

Liming is a safe and effective remediation practice for Cd contaminated acid paddy soil. The fate of Cd can also be strongly influenced by redox chemistry of sulfur. But it is unclear if, to what extent and how the combination of liming and sulfur mediation could further control Cd uptake by paddy rice. A rice cultivation pot experiment was conducted to evaluate the impact of different sulfur forms (S0 and SO42- in K2SO4) on the solubility, uptake and accumulation of Cd in the soil-paddy rice system and how liming and reducing organic carbon mediate the process. Results showed that under neutral soil circumstances achieved by liming, co-application of K2SO4 and glucose significantly reduced brown rice Cd by 33%, compared to liming alone. They made it more readily for Cd2+ to be precipitated into CdS/CdS2 or co-precipitate with newly formed FeS/FeS2/iron oxides. The higher pH balancing capability of K2SO4 as well as liming kept the newly formed sulfide or iron containing minerals negatively charged to be more prone to adsorb Cd2+, that kept the porewater Cd2+ the lowest among all the treatments. Individual K2SO4 showed significant promoting effect on soil Cd solubility due to SO42- chelation effect. Furthermore, K2SO4 had much weaker inhibiting effect on Cd translocation from root to grain, it showed no significant attenuating effect on brown rice Cd. S0 containing treatments displayed weaker or no attenuating effect on brown rice Cd due to its strong soil acidification effect. On the basis of liming, organic carbon induced sulfur (K2SO4) mediation showed great application potential for safe production on large areas of acid paddy soil contaminated by Cd.

Recently, the nuclear receptor farnesoid X receptor (FXR) has been considered to be a liver tumor suppressor. However, the role of FXR in liver cancer invasion and metastasis remains unclear. The results of the current study demonstrated that FXR suppressed the migratory and invasive capacities of SK-Hep-1 cells in vitro and that FXR overexpression inhibited local invasion and lung metastasis of SK-Hep-1 ×enografts in vivo. Bioinformatics analysis of the gene expression profile of SK-Hep-1 cells with different FXR levels indicated that FXR may regulate the Wnt/β-catenin pathway. Compared with controls, FXR-overexpressing SK-Hep-1 cells exhibited decreased expression of β-catenin target genes and reduced nuclear translocation of β-catenin proteins in vitro and in vivo. In conclusion, these results indicated that FXR may suppress SK-Hep-1 cell invasion and metastasis by suppressing the Wnt/β-catenin signaling pathway. The current study provided novel insight into the diagnosis and treatment of liver cancer.

International audience; Increasing use of emerging per- and polyfluoroalkyl substances (PFASs) has caused extensive concerns around the world. Effective detection methods to trace their pollution characteristics and environmental behaviors in complex soil-crop systems are urgently needed. In this study, a reliable and matrix effect (ME)-free method was developed for simultaneous determination of 14 legacy and emerging PFASs, including perfluorooctanoic acid, perfluorooctane sulfonate, 6 hydrogenous PFASs, 3 chlorinated PFASs, and 3 hexafluoropropylene oxide homologues, in 6 crop (the edible parts) and 5 soil matrices using ultrasonic extraction combined with solid-phase extraction and ultraperformance liquid chromatography-mass spectrometry (MS)/MS. The varieties of extractants and cleanup cartridges, the dosage of ammonia hydroxide, and the ME were studied to obtain an optimal pretreatment procedure. The developed method had high sensitivity and accuracy with satisfactory method detection limits (2.40-83.03 pg/g dry weight) and recoveries (72-117%) of all target analytes in matrices at five concentrations, that is, 0.1, 1, 10, 100, and 1000 ng/g. In addition, the ME of this method (0.82-1.15) was negligible for all PFASs, even considering 11 different matrices. The successful application of the ME-free method to simultaneously determine the legacy and emerging PFASs in crop and soil samples has demonstrated its excellent practicability for monitoring emerging PFASs in soil-crop systems.

Exploiting efficient and economical electrocatalysts for hydrogen evolution reaction (HER) is critical for sustainable energy systems. Herein we engineer a novel nanocomposite (RuP/NP-C) comprising ultrafine RuP nanoparticles encapsulated in N, P co-doped porous carbon derived from a well-defined Ru3+ incorporated phytic acid–polyaniline composite. Benefitting from its unique composition and architecture with full exposure of active sites, rapid mass/charge transfer, and improved structural robustness, RuP/NP-C nanocomposite can exhibit respectable HER performance. Significantly, from experimental and theoretical investigations, it is revealed that charge redistribution occurs due to interfacial electronic interaction between RuP and NP-C, leading to electronic modulation of RuP with upshift of the d-band center relative to Fermi level, thereby yielding optimal hydrogen binding strength for HER. This study highlights a promising route to tailor the electronic state of catalyst via interfacial electronic effect for boosted catalytic property.

Benzophenone (BP)-type ultraviolet (UV) filters are widely used in personal care products. Some of them have been identified as endocrine disrupting chemicals. However, little is known about the occurrence of BP-type UV filters in paired maternal-fetal samples. In this study, we investigated the occurrence of eight BP-type UV filters in paired maternal-fetal samples collected from Southern China. Among target analytes, only benzophenone-3 (BP-3) was frequently (detection rate 80%) detected in maternal-fetal samples, i.e., maternal serum (MS), cord serum (CS), maternal urine (MU) and amniotic fluid (AF). BP-3 was the dominant compound in MS (median: 0.14 ng/mL), CS (0.16) and AF (0.12); whereas MU was dominated by benzophenone-1 (BP-1, 2.85). The median CS/MS ratios (i.e., placental transfer rates) of 4-hydroxy benzophenone (4-OH-BP, 2.35), BP-1 (1.52), benzophenone-4 (BP-4, 1.06), and BP-3 (1.03) were higher than 1.0, suggesting that exposure levels of these chemicals in fetuses were greater than those in mothers. Significant positive correlations (r = 0.667, p 0.001) of BP-3 concentrations were found between MS and CS, which suggested that MS could be an indicator of fetal exposure to BP-3. Furthermore, the CS/MS ratios of 4-OH-BP, BP-1, BP-3, and benzophenone-8 (BP-8) increased with decreasing molecular weight or log K

Photocatalytic degradation of per- and polyfluoroalkyl substances (PFAS) remains insufficient. It is vital to investigate the structure–activity relationship between exposed facets and photocatalytic activity of PFAS. In this study, BiOCl nanosheets with predominantly exposed {0 1 0} or {0 0 1} facets (i.e. {0 1 0}-BiOCl or {0 0 1}-BiOCl) were synthesized via the hydrothermal method and applied for the photodegradation of perfluorooctanoic acid (PFOA). We observed that the degradation rate constant of PFOA via the {0 1 0}-BiOCl (0.0954 min−1) was 2.64-fold better than that of the {0 0 1}-BiOCl (0.0361 min−1) in photocatalytic activity. Density functional theory calculation results revealed that the higher catalytic activity of {0 1 0}-BiOCl was attributed to the in-situ generated surface oxygen vacancies (OVs) and the strong interaction with PFOA molecules via the bidentate adsorption configuration. {0 1 0}-BiOCl nanosheets with OVs exhibited the highest adsorption capacity (55.6 mg g−1h−1) and lowest adsorption energy (-0.399 eV) for PFOA molecules. The electron spin resonance spectroscopy and radical scavenging experiments showed that both photogenerated holes and surface hydroxyl radicals were generated on {0 1 0} facets that contributed to the degradation of PFOA; while only photogenerated holes were formed on {0 0 1} facets. Interestingly, F− ions as the by-products were prone to attaching to the BiOCl facets to block the catalytic sites. To recover the catalytic performance, we adopted a simple chemical precipitation approach to precipitate the F− by using Ca2+ ions. Our findings provide fundamental insights into the interface reactions during the photocatalytic degradation of PFOA.

Hepatocellular carcinoma (HCC) is one of the most common and rapidly fatal malignancies, for which hepatitis B virus (HBV) chronic infection constitutes a major risk factor. The lysosome-associated protein transmembrane-4 β gene (LAPTM4B) is a recently identified gene that was found to be overexpressed in several types of cancer. However, the role of LAPTM4B in HCC tumorigenesis and progression has not been clearly determined. The present study demonstrated that the mRNA as well as the protein levels of LAPTM4B were significantly upregulated in HCC specimens. Patients with higher levels of LAPTM4B mRNA in their HCC tissues tended to be of a younger age, HBsAg+, with an advanced Barcelona Clinic Liver Cancer stage. Moreover, LAPTM4B mRNA expression was positively associated with serum α -fetoprotein levels. We also observed that LAPTM4B was able to promote HCC cell proliferation, migration and invasion in vitro. In conclusion, our results indicated that LAPTM4B plays an important role in the promotion of hepatocarcinogenesis and cancer progression and may serve as a biomarker for the diagnosis and monitoring of HCC.

A nano zerovalent iron activated by persulfate process (nZVI-PS) was applied to degrade 2,2′,4,4′-tetrabromodiphenyl ether (BDE-47), which is representative of the polybrominated diphenyl ethers (PBDEs) found in electronic waste (e-waste) sites. The influences of Cu(II), Zn(II), and Ni(II) ions, which are co-present in electronic wastes were evaluated on the degradation process. Electron paramagnetic resonance (EPR) and quenching studies indicates that sulfate radicals (SO4−) and hydroxyl radicals (HO) were both responsible for the degradation of BDE-47 during the treatment. Zn(II) and Ni(II) inhibited BDE-47 degradation, possibly due to their negative reduction potentials leading to surface adsorption on or complexation with nZVI. Cu(II), however, enhanced the degradation of BDE-47. Characterization of the nZVI surface reveals that the catalytic activity of Cu(II) could be attributed to the synergistic effect of Cu(0)-Cu(III) and Fe(II)-Fe(III) redox pairs, which favored the continuous decomposition of PS and thus BDE-47 degradation. Overall, these findings indicate that nZVI can be used as an effective activator of PS for removal of the lower brominated BDEs (e.g., tetra-BDE) and the role of metal ions cannot be neglected, which provides a significant implication for the use of nZVI-PS system in e-waste contaminated site.

Six parabens and their four metabolites were measured in paired maternal serum (MS) and cord serum (CS) samples collected from 95 pregnant women to elucidate placental transfer of this class of compounds. Matched maternal urine (MU) and amniotic fluid (AF) collected from 13 of 95 pregnant women were also analyzed to examine partition of these chemicals between maternal and fetal tissues. The placental transfer rates (PTRs; concentration ratio of parabens between CS and MS) of methyl- (MeP), ethyl- (EtP), propyl-parabens (PrP) were 0.81, 0.63, and 0.60, respectively. Furthermore, the PTRs of OH-MeP (0.93) and OH-EtP (1.8) were higher than those of their corresponding parent parabens, which suggested that hydroxylation increased placental transfer rates of parabens. Structure-dependent placental transfer mechanisms were observed. A significant negative correlation between molecular weights (or log Kow) of MeP, EtP, PrP, and p-hydroxy benzoic acid (4-HB) and PTRs suggested passive diffusion as a mechanism of placental transfer of these chemicals. Nevertheless, other hydroxylated metabolites (OH-EtP, OH-MeP, and 3,4-dihydroxy benzoic acid (3,4-DHB)) showed a positive correlation between molecular weight (or log Kow) and PTRs, which suggested that the placental transfer is mediated by protein binding of these metabolites. The MU to MS concentration ratios of MeP (MU/MSMeP) and PrP (MU/MSPrP) were 71 and 81, respectively, and MU/MSMeP was two orders of magnitude higher than that found for the metabolite (MU/MSOH-MeP: 0.35), suggesting that hydroxylation metabolite reduced urinary elimination of parabens. To our knowledge, this is the first time to report the occurrence and distribution of parabens and their metabolites in paired maternal-fetal serum, urine, and AF samples in China. Our results provide novel information on placental transfer of parabens and their metabolites.

The nuclear receptor Farnesoid X Receptor (FXR) is likely a tumor suppressor in liver tissue but its molecular mechanism of suppression is not well understood. In this study, the gene expression profile of human liver cancer cells was investigated by microarray. Bioinformatics analysis of these data revealed that FXR might regulate the mTOR/S6K signaling pathway. This was confirmed by altering the expression level of FXR in liver cancer cells. Overexpression of FXR prevented the growth of cells and induced cell cycle arrest, which was enhanced by the mTOR/S6K inhibitor rapamycin. FXR upregulation also intensified the inhibition of cell growth by rapamycin. Downregulation of FXR produced the opposite effect. Finally, we found that ectopic expression of FXR in SK-Hep-1 xenografts inhibits tumor growth and reduces expression of the phosphorylated protein S6K. Taken together, our data provide the first evidence that FXR suppresses proliferation of human liver cancer cells via the inhibition of the mTOR/S6K signaling pathway. FXR expression can be used as a biomarker of personalized mTOR inhibitor treatment assessment for liver cancer patients.

With the phase out of perfluorooctanesulfonate (PFOS) and perfluorooctanoic acid (PFOA), the composition profiles of poly- and perfluoroalkyl substance (PFAS) in our living environment are unclear. In this study, 25 PFASs were analyzed in indoor dust samples collected from urban, industrial, and e-waste dismantling areas in China. PFOS alternatives, including 6:2 chlorinated polyfluorinated ether sulfonate (6:2 Cl-PFESA) (median: 5.52 ng/g) and 8:2 chlorinated polyfluorinated ether sulfonate (8:2 Cl-PFESA) (1.81 ng/g), were frequently detected. By contrast, PFOA alternatives, such as hexafluoropropylene oxide dimer acid (HPFO-DA, Gen-X) and ammonium 4,8-dioxa-3H-perfluorononanoate (ADONA), were not found in any of the dust samples. As expected, all legacy PFASs were widely observed in indoor dust, and 4 PFAS precursors were also detected. Dust concentrations of 6:2 Cl-PFESA were strongly correlated (p 0.05) with those of 8:2 Cl-PFESA regardless of sampling sites. 6:2 Cl-PFESA was also significantly associated with that of PFOS in industrial and e-waste (p 0.01) areas. Association analysis suggested that the sources of PFOS and its alternatives are common or related. Although ∑Cl-PFESA concentration was lower than that of PFOS (17.4 ng/g), industrial areas had the highest 6:2 Cl-PFESA/PFOS ratio (0.63). Composition profiles of PFASs in the industrial area showed the forefront of fluorine change. Thus, the present findings suggested that Cl-PFESAs are widely used as PFOS alternatives in China, and high levels of human Cl-PFESA exposure are expected in the future. Short-chain PFASs (C4-C7) were the predominant PFASs found in dust samples, contributing to over 40% of ∑total PFASs. Furthermore, perfluoro-1-butanesulfonate/PFOS and perfluoro-n-butanoic acid (PFBA)/PFOA ratios were 2.8 and 0.72, respectively. These findings suggested shifting to the short-chain PFASs in the environment in China. To the authors knowledge this is the first study to document the levels of 6:2 Cl-PFESA, 8:2 Cl-PFESA in indoor dust.

Novel alternatives of perfluorooctane sulfonate (PFOS), chlorinated polyfluorinated ether sulfonates (Cl-PFAESs) are increasingly being detected in the aquatic and terrestrial environment. Previous studies mainly focused on aquatic biota; however, the knowledge about the ecotoxicological risk they pose to terrestrial plants was still lacking. In this study, the accumulation of two Cl-PFAES (6:2 and 8:2 Cl-PFAES) and PFOS in wheat seedlings at environmentally relevant levels (50 and 100 μg L−1) was investigated. Concentrations of Cl-PFAESs in the roots were an order of magnitude higher than those in shoots, indicating that they were primarily accumulated in the roots. The values of root and shoot bioconcentration factor was comparable between 6:2 Cl-PFAES and PFOS. However, these indexes of 8:2 Cl-PFAES were 42–91% higher and 70–76% lower than PFOS, respectively. As a result, 6:2 Cl-PFAES had a similar accumulation pattern as PFOS, whereas 8:2 Cl-PFAES was predominantly restricted to the roots, which might be attributed to their hydrophobicity and carbon chain length. In addition, at 250 mg L−1 of Cl-PFAESs, plant biomass and pigment content were 24–30% and 0.4–18%, respectively, which were lower than those of PFOS. As compared with PFOS, Cl-PFAESs induced higher levels of root membrane permeability, reactive oxygen species and malondialdehyde content, as well as reduced the activities of antioxidant enzymes and glutathione content. These suggested the occurrence of a severer oxidative damage and the breakdown of the antioxidant defence system in wheat cells. Therefore, we conclude that Cl-PFAESs might pose a higher potential threat to the environment than PFOS.

Bisphenol A (BPA) and its alternatives are suspected endocrine disruptors. However, prenatal exposure and transplacental transfer of bisphenols (BPs is still limited. Therefore, BPA and its six alternatives in maternal serum (MS), maternal urine (MU), cord serum (CS), and amniotic fluid (AF) samples collected from 106 maternal-fetal pairs in an e-waste dismantling site in Southern China were determined. Bisphenol AF (BPAF) and bisphenol S (BPS) were the dominant BPA alternatives observed in MS and CS, and the geometric mean (GM) concentration of BPAF (0.013 ng/mL in MS, 0.097 ng/mL in CS) and BPS (0.01 ng/mL in MS, 0.03 ng/mL in CS) in MS and CS was lower than that of BPA (0.5 ng/mL in MS, 1.2 ng/mL in CS). The ratios of BPA concentrations between MU and MS (MU:MS ratio) were over three times higher than those of AF and CS (AF:CS ratio), thereby suggesting low biotransformation/metabolism of BPA in fetuses. The placental transfer rates of BPs (i.e., CS:MS ratio) were compound-specific (BPAF 3.26, BPA 1.94, BPS 1.11). Results suggest that BPA and its alternatives can pass through the placental barrier. The placental transfer rates of BPs are positively related to molecular weight or log Kow values. This finding indicates that an active transport is responsible for the placental transfer of BPs. Keywords: Bisphenol A, BPA alternatives, E-waste, Placental transfer

Fe(II)-catalyzed peroxymonosulfate (PMS) activation process was able to degrade persistent organic pollutants, such as polybrominated diphenyl ethers (PBDEs), but the slow transformation rate from the generated Fe(III) to Fe(II) restricted the efficiency of this process. In this study, we found that the addition of small quantities of gallic acid (GA), a model compound of natural polyphenols, in the Fe(III)/PMS process (namely GA/Fe(III)/PMS process) could exert a long-term influence on Fe(II) recycle and accelerated the degradation of 2,2′,4,4′-tetrabromodiphenyl ether (BDE47) over 72 h. Under conditions of 20.3 µM GA, 13.6 µM Fe(III) and 400 µM PMS, the degradation efficiency of BDE47 reached 85%, which was 9.4 times higher than that in the Fe(III)/PMS process. The degradation kinetics can be divided into an initial “fast stage” (kobs1 = 0.298 h−1) and a second “slow stage” (kobs2 = 0.021 h−1). Aromatic radicals such as hydroxycyclohexadienyl radical (poly-HCD ) produced by the attack of SO4 −/HO on GA was proposed to be responsible for Fe(II) recycle in the first stage, while ring-opened products following SO4 −/HO attack of GA-quinone mainly initiated Fe(III) reduction in the second stage. Owing to the multiple Fe(III) reduction pathways, PMS would be continuously activated by Fe(II) to form SO4 − and HO , which were the dominant reactive species for BDE47 degradation. Finally, natural polyphenols extracted from green tea were proven effective in enhancing BDE47 degradation in Fe(III)/PMS process. This study not only provides a new way to propagate Fe(II)-activated persulfate chain reactions for the degradation of refractory organic contaminants, like PBDEs, but also sheds new insight into the reactivity of organic byproducts toward Fe in PMS-based oxidation system.

This study developed a cost-effective and eco-friendly method by coupling plant extracts (take green tea for example) and Fe(III) to reduce Cr(VI) and precipitate Cr(III). At acidic pH, 1.43 mM Fe(III) combined with 1.33 g/L green tea extracts could reduce 93% of Cr(VI) in 180 min, which was much larger than ˜50% by green tea extracts alone. Moreover, 52% of Cr(III) could automatically precipitate out as mixed Fe(III)-Cr(III) (oxy)-hydroxide solids. In the viewpoint of mechanism, polyphenols in green tea extracts were the reactive constituents and transformed Fe(III) to Fe(II), by which step the aqueous Fe(II) level was maintained to continuously reduce Cr(VI) to Cr(III), and thus accelerating Cr(VI) reduction. The generated Fe(III) partially participated in the reaction with polyphenols again and some Fe(III) formed precipitates with Cr(III). Overall, the electron transfers in the polyphenol-Fe-Cr cyclic reactions made Fe(III) used for multiple times, thus accelerated Cr(VI) reduction. The applicability of the combined process was further verified by removing 100% and 70% of Cr(VI) from electroplating wastewater and contaminated soil, respectively. As polyphenols can be derived from plant wastes and Fe(III) is naturally abundant, this study provides a promising method for in situ remediation of Cr(VI)-contaminated sites.

In the present study, concentrations of bisphenol A (BPA) and its six alternatives were quantified in serum samples collected from elder population living around an e-waste recycling facilities as well as an reference area in China. BPA, bisphenol AF (BPAF), and bisphenol F (BPF) were frequently detected (detection rates:65%) in serum samples collected from residents living near e-waste dismantling facilities, with geometric mean (GM) concentrations of 3.2, 0.0074, and 0.062 ng/mL, respectively. The detection frequencies of other four bisphenols (BPs) in serum samples were lower than 25%, regardless of the sampling areas. Significant difference (Mann-Whitney U-test, p 0.05) was observed in the serum concentration of BPA, but not BPAF and BPF, between the e-waste recycling and reference areas. This finding indicated e-waste dismantling activities are correlated with human BPA exposure. Significant higher (p 0.05) detection rates of donors who had abnormal fasting blood glucose (FBG) levels were found in e-waste recycling areas (45%) than those found in reference area. Our results suggested BPA and BPAF exposure might associated with abnormal FBG in participants living in e-waste sites. To our knowledge, this study is first determination of BPs in serum samples and assessment of health risk of elderly people from BPs exposure in e-waste dismantling area.

Phthalate acid esters (PAEs) are of particular concern due to their potential environmental risk to human and nonhuman organisms. Although uptake of PAEs by plants has been reported by several researchers, information about the intracellular distribution and uptake mechanisms of PAEs is still lacking. In this study, a series of hydroponic experiments using intact pumpkin (Cucurbita moschata) seedlings was conducted to investigate how di-n-butyl phthalate (DnBP), one of the most frequently identified PAEs in the environment, enters and is distributed in roots. DnBP was transported into subcellular tissues rapidly in the initial uptake period (

Soil washing is one of the few permanent treatment alternatives for removing metal contaminants. Ethylenediaminetetraacetic acid (EDTA) and its salts can substantially increase heavy metal removal from contaminated soils and have been extensively studied for soil washing. However, EDTA has a poor utilization ratio due to its low selectivity resulting from the competition between soil major cations and trace metal ions for chelation. The present study evaluated the potential for soil washing using EDTA and three of its derivatives: CDTA (trans-1,2-cyclohexanediaminetetraacetic acid), BDTA (benzyldiaminetetraacetic acid), and PDTA (phenyldiaminetetraacetic acid), which contain a cylcohexane ring, a benzyl group, and a phenyl group, respectively. Titration results showed that PDTA had the highest stability constants for Cu(2+) and Ni(2+) and the highest overall selectivity for trace metals over major cations. Equilibrium batch experiments were conducted to evaluate the efficacy of the EDTA derivatives at extracting Cu(2+), Zn(2+), Ni(2+), Pb(2+), Ca(2+), and Fe(3+) from a contaminated soil. At pH 7.0, PDTA extracted 1.5 times more Cu(2+) than did EDTA, but only 75% as much Ca(2+). Although CDTA was a strong chelator of heavy metal ions, its overall selectivity was lower and comparable to that of EDTA. BDTA was the least effective extractant because its stability constants with heavy metals were low. PDTA is potentially a practical washing agent for soils contaminated with trace metals.

Acid mine drainage (AMD) resulting from the oxidation of pyrite and other metal sulfides has caused significant environmental problems, including acidification of rivers and streams as well as leaching of toxic metals. With the goal of controlling AMD at the source, we evaluated the potential of tetraethylorthosilicate (TEOS) and n-propyltrimethoxysilane (NPS) coatings to suppress pyrite oxidation. The release of total Fe and SO4(-2) from uncoated and coated pyrite in the presence of a chemical oxidizing agent (H2O2) or iron-oxidizing bacteria (Acidithiobacillus ferrooxidans) was measured. Results showed that TEOS- and NPS-based coatings reduced chemical oxidation of pyrite by as much as 59 and 96% (based on Fe release), respectively, while biological oxidation of pyrite was reduced by 69 and 95%, respectively. These results were attributed to the formation of a dense network of Fe-O-Si and Si-O-Si bonds on the pyrite surface that limited permeation of oxygen, water, and bacteria. Compared with results for TEOS-coated pyrite, higher pH and lower concentrations of total Fe and SO4(-2) were observed for oxidation of NPS-coated pyrite, which was attributed to its crack-free morphology and the presence of hydrophobic groups on the NPS-based coating surface. The silane-based NPS coating was shown to be highly effective in suppressing pyrite oxidation, making it a promising alternative for remediation of AMD at its source.

Indirect attack mode has been a serious threat to server security due to the covert nature. This paper focuses on a new application-layer indirect attack which exploits the communication mechanism of proxy server to attack the targets. Such type of attacks is not easy to be discovered by most existing defense systems since malicious traffic hides in the aggregated traffic. Moreover, the sources of the attack traffic and normal traffic are indistinguishable, because both of them share the same IP of the last proxy server. In this paper a novel server-side defense scheme is proposed to resist such covert indirect attacks. An improved semi-Markov model is proposed to describe the dynamic behavior process of aggregated traffic. The model includes two stochastic processes. The observable process represents the changes in the appearance features of the observed traffic, while the unobservable process is a semi-Markov chain which represents the underlying time-varying patterns used to generate the outgoing traffic by a proxy server. An algorithm is proposed to estimate the model parameters. An objective function is defined to evaluate the normality of a proxy server's access behavior. Numerical results based on real traffic demonstrate the performance of the proposed method.

The nuclear receptor farnesoid X receptor (FXR) acts as a liver protector by regulating normal liver homeostasis. Spontaneously developed liver tumors have been found in FXR-null mice. However, the role of FXR in the tumorigenesis of human hepatocellular carcinoma (HCC) is still poorly understood. In this study, we measured the expression of FXR and its primary target gene, small heterodimer partner, and analyzed the clinical significance of FXR expression in HCC patients. A lentiviral vector that selectively overexpresses FXR was used to investigate the function of FXR in HCC cell proliferation both in vitro and in vivo . Our data showed that in human HCC, FXR expression was significantly reduced and was positively correlated with multiple malignant clinicopathological characteristics. Lentivirus-mediated exogenous FXR expression resulted in a marked increase of small heterodimer partner expression, significant repression of liver cancer cell proliferation, and tumor growth in nude mice. These results suggest that FXR may be of clinical and pharmacological importance as a promising biomarker of HCC.

Uptake and accumulation by plants is a significant pathway in the migration and transformation of phthalate esters (PAEs) in the environment. However, limited information is available on the mechanisms of PAE metabolism in plants. Here, we investigated the metabolism of di-n-butyl phthalate (DnBP), one of the most frequently detected PAEs, in pumpkin (Cucurbita moschata) seedlings via a series of hydroponic experiments with an initial concentration of 10 mg L-1. DnBP hydrolysis occurred primarily in the root, and two of its metabolites, mono-n-butyl phthalate (MnBP) and phthalic acid (PA), were detected in all plant tissues. The MnBP concentration was an order of magnitude higher than that of PA in shoots, which indicated MnBP was more readily transported to the shoot than was PA because of the former's dual hydrophilic and lipophilic characteristics. More than 80% of MnBP and PA were located in the cell water-soluble component except that 96% of MnBP was distributed into the two solid cellular fractions (i.e., cell wall and organelles) at 96 h. A 13-20% and 29-54% increase of carboxylesterase (CXE) activity shown in time-dependent and concentration-dependent experiments, respectively, indicated the involvement of CXEs in plant metabolism of DnBP. The level of CXE activity in root subcellular fractions was in the order: the cell water-soluble component (88-94%) >> cell wall (3-7%) > cell organelles (3-4%), suggesting that the cell water-soluble component is the dominant locus of CXE activity and also the domain of CXE-catalyzed hydrolysis of DnBP. The addition of triphenyl phosphate, a CXE inhibitor, led to 43-56% inhibition of CXE activity and 16-25% increase of DnBP content, which demonstrated the involvement of CXEs in plant metabolism of DnBP. This study contributes to our understanding of enzymitic mechanisms of PAE transformation in plants.

Soil washing is one of the few permanent treatment alternatives for removing metal contaminants. Ethylenediaminetetraacetic acid and its salts (EDTA) is very effective at removing cationic metals and has been utilized globally. However it is ineffective for anionic metal contaminants or metals bound to soil organic matter. The simultaneous removal of cationic and anionic metal contaminants by soil washing is difficult due to differences in their properties. The present study evaluated the potential of a washing process using two synthesized EDTA-derivatives, C 6 HEDTA (2,2′-((2-((carboxymethyl)(2-(hexanoyloxy)ethyl)amino)ethyl)azanediyl)diacetic acid) and C 12 HEDTA (2,2′-((2-((carboxymethyl) (2-(dodecanoyloxy)ethyl)amino)ethyl)azanediyl)diacetic acid), which consist of a hydrophilic polycarboxylic moiety and a hydrophobic moiety with a monoalkyl ester group. A series of equilibrium batch experiments at room temperature were conducted to investigate the efficacy of C 6 HEDTA and C 12 HEDTA as extractants for both oxyanion Cr(VI) and cationic Cu(II). Results showed that either C 6 HEDTA or C 12 HEDTA can extract both Cr(VI) and Cu(II) from humic acid simultaneously. However, C 6 HEDTA was less effective for Cr(VI) probably because it has no surface activities to increase solubility of humic acid, like C 12 HEDTA. Extraction of Cr(VI) was mainly attributed to the decreased surface tension and enhanced solubility of organic matter. Extraction of Cu(II) was attributed to both the Cu(II) chelation and enhanced solubility of humic acid. It was demonstrated that the hydrophilic polycarboxylic moiety of C 12 HEDTA chelates cations while the monoalkyl ester group produces surface active properties that enhance the solubility of humic acid.

Lead sorption capacity and mechanisms by sludge-derived biochar (SDBC) were investigated to determine if treatment of acid mine drainage (AMD) containing metals with SDBC is feasible. It was found that the biochar derived from pyrolysis treatment of sewage sludge could effectively remove Pb(2+) from acidic solution with the capacities of 16.11, 20.11, 24.80, and 30.88mgg(-1) at initial pH 2, 3, 4 and 5, respectively. Lead sorption processes were pseudo-second order kinetic and faster at a higher pH. Furthermore, the relative contribution of both inorganic mineral composition and organic functional groups of SDBC for Pb(2+) removal mechanisms, was quantitatively studied at pH 2-5. The results showed that Pb sorption primarily involved the coordination with organic hydroxyl and carboxyl functional groups, which was 38.2-42.3% of the total sorbed Pb varying with pH, as well as the coprecipitation or complex on mineral surfaces, which accounted for 57.7-61.8% and led to a bulk of Ca(2+) and Mg(2+) release during sorption process. A new precipitate was solely observed on Pb-loaded SDBC as 5PbO·P(2)O(5)·SiO(2)(lead phosphate silicate) at initial pH 5, confirmed by XRD and SEM-EDX. The coordination of Pb(2+) with carboxyl and hydroxyl functional groups was demonstrated by FT-IR, and the contribution of free carboxyl was significant, ranging from 26.1% to 35.5%. Results from this study may suggest that the application of SDBC is a feasible strategy for removing metal contaminants from acid solutions.

A strain of sulfate-reducing bacteria, designated strain 'DBM', was isolated from sediments of a mining area. Phylogenetic analysis of the 16S rRNA gene sequence of the isolate revealed that it was related to members of the genus Citrobacter, with C. AzoR-4, C. freundii, C. braakii and C. werkmanii being the most closely related species (sequence similarity up to 98%). Few studies have been done on sulfate reduction ability in Citrobacter. Electron microscopy studies showed that the morphology of the strain DBM was rod-shaped. Strain DBM reduced 10mM of sulfate completely to sulfide within 7d, and it recovered its sulfate reduction ability after 7d of aerobic growth. Furthermore, strain DBM effectively precipitated 0.40 mM copper during its growth. Elemental composition of the resulting microbial precipitate was studied using electro-dispersive X-ray spectroscopy, and it was found that the ratio of S:Cu was 1.07. The result was consistent with the formation of copper sulfide. Heavy metal precipitation by Citrobacter sp. strain DBM was a phenomenon that may be useful in the bioremediation of acid mine drainage.

Cholesterol 7alpha-hydroxylase (CYP7a1) is the rate-limiting enzyme in the classic pathway of bile acid synthesis. Expression of CYP7a1 is regulated by a negative feedback pathway of bile acid signaling. Previous studies have suggested that bile acid signaling is also required for normal liver regeneration, and CYP7a1 expression is strongly repressed after 70% partial hepatectomy (PH). Both the effect of CYP7a1 suppression on liver regrowth and the mechanism by which 70% PH suppresses CYP7a1 expression are unknown. Here we show that liver-specific overexpression of an exogenous CYP7a1 gene impaired liver regeneration after 70% PH, which was accompanied by increased hepatocyte apoptosis and liver injury. CYP7a1 expression was initially suppressed after 70% PH in an farnesoid X receptor/ small heterodimer partner-independent manner; however, both farnesoid X receptor and small heterodimer partner were required to regulate CYP7a1 expression at the later stage of liver regeneration. c-Jun N-terminus kinase and hepatocyte growth factor signaling pathways are activated during the acute phase of liver regeneration. We determined that hepatocyte growth factor and c-Jun N-terminus kinase pathways were involved in the suppressing of the CYP7a1 expression in the acute phase of live regeneration. Taken together, our results provide the significance that CYP7a1 suppression is required for liver protection after 70% PH and there are two distinct phases of CYP7a1 gene regulation during liver regeneration.

The copolymer poly(fluorene-co-thiophene) (PFT) has strong absorption in the visible light region. In this paper, PFTs with four different thiophene contents were evaluated for their suitability as photosensitizers of TiO2. All four of the PFTs were capable of being excited by light with wavelengths above 455 nm, and all had reductive potentials more negative than the conduction band potential of TiO2. Consequently, it was deemed that transfer of electrons from the excited PFTs to the conduction band of TiO2was thermodynamically possible. PFTs with higher thiophene content had more electron transitions in the excited state, resulting in increased photocatalytic activity of PFT-sensitized TiO2. The method used to prepare the combined PFT/TiO2photocatalyst affected its photocatalytic activity. Best results in this study were achieved by dropwise addition of a tetrahydrofuran solution of PFT to a stirred TiO2/ethanol suspension.

Liver mass depends on one or more unidentified humoral signals that drive regeneration when liver functional capacity is diminished. Bile acids are important liver products, and their levels are tightly regulated. Here, we identify a role for nuclear receptor–dependent bile acid signaling in normal liver regeneration. Elevated bile acid levels accelerate regeneration, and decreased levels inhibit liver regrowth, as does the absence of the primary nuclear bile acid receptor FXR. We propose that FXR activation by increased bile acid flux is a signal of decreased functional capacity of the liver. FXR, and possibly other nuclear receptors, may promote homeostasis not only by regulating expression of appropriate metabolic target genes but also by driving homeotrophic liver growth.

A series of novel carbazole-azo binary compounds was synthesized by modifying 9H-carbazole. The permanent dipole moments of their ground states were estimated by Fishtine method. A simple way generated from solvatochromic method was successful to calculate their first hyperpolarizabilities in the order of 10 −28 esu, which are comparable with Disperse Red 1 (DR 1). The first hyperpolarizability was highly related to the structure of the related carbazole-azo binary compound. Using their doped poly(methyl methacrylate) (PMMA) films, a refractive index change of these films was determined up to 0.0010 at the incident wavelength of 632.8 nm in the two-photon holography experiment. This demonstrated that these compounds exhibited a strong two-photon behavior.

A series of novel materials of carbazole-azo binary compound doped polymer were introduced for holographic storage. Optical absorption changes orientation distribution of trans isomer of azobenzene moiety that results in the modulation of the refractive indices of azo doped polymer film without additional pump light. The diffraction efficiency of the 15 μm thick film of 4′-carbazolylhexoxyl-2-methyl-4-nitro azobenzene is about 0.65%.

International audience; Effective dehalogenation by nanoscale zerovalent iron (nZVI) has been reported. In this study, the effects of Ni2+, Cu2+ ions, and the nonionic surfactant Tween-80 on dechlorination of 2,2', 5,5'-tetrachlorinated biphenyl (PCB-52) by nZVI were investigated in aqueous solution. The rate of dechlorination was significantly enhanced by Ni2+, while Cu2+ had a less significant catalytic effect. Ni2+ and Tween-80 used in combination synergistically enhanced dechlorination of PCB-52 by nZVI, although the enhancement by Tween-80 was inhibitory in the presence of Cu2+ and insignificant in the absence of both metal ions. Congener specificity in the dechlorination pathway resulted from the preferential retention of ortho-chlorine, which restricted the formation of environmentally toxic coplanar PCB congeners. The application of nZVI dehalogenation enhanced by Ni2+ and Tween-80 is a promising technique for posttreatment of PCB-contaminated soil washing solutions.

Study of the relationship between plant litter-derived dissolved organic matter (DOM) and organic pollutant transport in soil is important for understanding the role of forest litter carbon cycling in influencing pollutant behaviour and fate in forest soil. With the aim of providing insight into the capacity of plant litter-derived DOM to influence sorption and desorption of selected polycyclic aromatic hydrocarbons (PAHs) on soil, batch experiments were carried out with application of a sorption-desorption model incorporating DOM effects. Freshly fallen pine (Pinus elliottii) needles were used as the source of organic matter. Input of the pine needle litter-derived DOM was found to significantly decrease desorption hysteresis as well as soil adsorption capacity of phenanthrene (PHE) and fluoranthene (FLA). Addition of 1 728 mg L−1 dissolved organic carbon (DOC) lowered the organic carbon-normalized sorption distribution coefficient of PHE from 7 776 to 2 541 L kg−1 C and of FLA from 11 503 to 4 368 L kg−1 C. Decreases of the apparent sorption-desorption distribution coefficients of PHE and FLA with increased DOC concentration indicated that DOM favored desorption of PAHs from soil. Increases in the fraction of apparently dissolved PAHs were attributable to the dissolved PAH-DOM complexes, accounting for the dissolved proportions of 39% to 69% for PHE and 26% to 72% for FLA in the sorption and desorption processes as the concentration of the added DOM solution rose from 0 to 1 728 mg L−1. Our results suggest that pine needle litter-derived DOM can have a substantial effect of inhibiting PAHs sorption and promoting PAHs desorption, thus leading to enhanced leaching in soil, which should be taken into account in risk assessment of PAHs accumulated in forest soil.

This study was to evaluate and compare the clinical and pathological characteristics and patient outcomes after hepatic resection for different stages of HCC according to the Barcelona Clinic Liver Cancer (BCLC) classification system.Three hundred and sixteen primary hepatectomies for HCC were divided into stage 0-c, according to BCLC classification. The clinicopathological variables of the patients in each group were compared statistically.There were significant differences in the incidence of capsular invasion, α-fetoprotein, blood loss, blood transfusion and tumor related number among each of the stage 0-C, respectively (p0.05). Disease-free survival was influenced by histopathological grade (p=0.000), tumor capsule (p=0.015), tumor related number (p=0.000) and BCLC (p=0.000). Overall survival was influenced by histopathological grade (p=0.000), tumor capsule (p=0.035), tumor related number (p=0.005), cirrhosis (p=0.000) and BCLC (p=0.000).HCC in stage 0 and A were closely correlated with a better prognosis, which reflected the relatively benign pathobiological features of HCC at an early developmental stage. In comparison, HCC in stages B and C exhibited a tendency towards a more aggressive phenotype. Our findings suggest that stage B classification is optimal for estimating the biological behavior and clinical prognosis of patients undergoing partial hepatectomy for early stage HCC.

BACKGROUND/AIMS This study was to evaluate and compare the clinical and pathological characteristics and patient outcomes after hepatic resection for different stages of HCC according to the Barcelona Clinic Liver Cancer (BCLC) classification system. METHODOLOGY Three hundred and sixteen primary hepatectomies for HCC were divided into stage 0-c, according to BCLC classification. The clinicopathological variables of the patients in each group were compared statistically. RESULTS There were significant differences in the incidence of capsular invasion, α-fetoprotein, blood loss, blood transfusion and tumor related number among each of the stage 0-C, respectively (p