| 1. |
- Li, Yingming, et al.
(författare)
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Levels and vertical distributions of PCBs, PBDEs, and OCPs in the atmospheric boundary layer : observation from the Beijing 325-m meteorological tower
- 2009
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Ingår i: Environmental Science and Technology. - : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 43:4, s. 1030-1035
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Tidskriftsartikel (refereegranskat)abstract
- Polyurethane foam disk passive air sampling was carried out to investigate the levels, vertical distributions, and potential sources of polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs) and organochlorine pesticides (OCPs) in the atmospheric boundary layer of an urban site in Asia. Sampling was performed at nine heights (15, 47, 80, 120, 160, 200, 240, 280, 320 m) of the 325-m meteorological tower in Beijing, China over three 2-month periods between December 2006 and August 2007. This is the first study to report vertical variations of PBDEs in the ABL and one of only a few studies to investigate vertical distributions of persistent organic pollutants. The levels of sigma19PCBs and sigma8PBDEs were relatively low, ranging from 22 to 65 and from 2.3 to 18 pg m-3, respectively. Air concentrations of gamma-HCH were high, with values in the range of 39-103 pg m-3 in winter, 100-180 pg m-3 in spring, and 115-242 pg m-3 in summer, respectively. alpha-HCH concentrations ranged from 20 to 86 pg m-3, p,p'-DDT between 7.3 and 78 pg m-3, and HCB between 15 and 160 pg m-3. The seasonal variations of PCBs, PBDEs, and OCPs may reflect different sources for these chemicals, such as those related with regional use (gamma-HCH), volatilization/re-emission (PBDEs, PCBs, alpha-HCH), and pesticide impurities (HCB). Although the performance reference compounds (PRCs) were spiked before deployment, the sampling rates showed strong dependency on wind speeds, resulting in large variations in uptake rates in the ABL, ranging from approximately 7.0 m3 day-1 at ground level to 11 m3 day-1 at 320 m. Levels of PCBs, PBDEs, and OCPs decreased with increasing ABL height indicating the potential of Beijing as the local sources.
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| 2. |
- Ruan, Ting, et al.
(författare)
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Identification and evaluation of a novel heterocyclic brominated flame retardant tris(2,3-dibromopropyl) isocyanurate in environmental matrices near a manufacturing plant in southern China
- 2009
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Ingår i: Environmental Science and Technology. - : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 43:9, s. 3080-3086
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Tidskriftsartikel (refereegranskat)abstract
- A brominated flame retardant (BFR), hexabrominated heterocyclic tris-(2,3-dibromopropyl) isocyanurate (TBC), was identified,forthe first time, in the natural environment.The chemical was found in river water (2.33-163 ng/L), surface sediments (85.0 ng/g-6.03 microg/g dry weight (dw)), soils (19.6-672 ng/g dw), earthworm (9.75-78.8 ng/g dw), and carp samples (12.0-646 ng/g dw) from a factory-polluted area in southern China. It was found that TBC can strongly adsorb to organic material in sediment, and a trend of decreasing concentration with distance from the source in soil and earthworm samples, combined with calculated Kow (octanol-water partition coefficient) and Koa (octanol-air partition coefficient), suggests its potential ability to undergo regional transportation through dust deposition. Calculated results showed high Kow (log Kow = 7.37) and bioaccumulation factor (BAF) (log BAF = 4.30) of this BFR and indicate that TBC has semivolatile properties and bioaccumulation characteristic in certain biological species. Quantitative structure property relationships (QSPRs) modeling revealed that TBC has Koa (log Koa = 23.68) and Kaw (air-water partition coefficient) (log Kaw = -16.31) values several orders higher than those of other BFRs. The identification of this chemical additive further reminds us that the production and usage of heterocyclic BFRs may cause potential contamination to the surrounding environment
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| 3. |
- Wang, Pu, et al.
(författare)
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Altitude dependence of polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) in surface soil from Tibetan Plateau, China
- 2009
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Ingår i: Chemosphere. - : Elsevier. - 0045-6535 .- 1879-1298. ; 76:11, s. 1498-1504
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Tidskriftsartikel (refereegranskat)abstract
- Remote mountain areas besides high latitude regions are beginning to receive increased attention in studying the transport and behavior of persistent organic pollutants (POPs). In the present work, surface soil samples were collected from the Tibetan Plateau, the highest plateau in the world which includes the northern slope of Mt. Qomolangma, to investigate the levels and trends of polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) along the altitudinal gradient. The average PCB and PBDE concentrations were 185.6 ng kg-1 dry weight (dw) (range 47.1-422.6 ng kg-1 dw) and 11.1 ng kg-1 dw (range 4.3-34.9 ng kg-1 dw), respectively. Regression analysis between the log-transformed TOC-normalized concentrations and the altitudes of the sampling sites showed two opposite trends with regard to altitude dependence: negative relationship with altitude below about 4500 m followed by a positive altitude dependence above this point. Considering minimum anthropogenic activities and very sparse precipitation in the north of Himalayas, the trends above 4500 m imply that the significant altitude dependence of these two groups of POPs were irrespective of pollution sources, but could be predicted by the global distillation effect involving cold condensation in high altitude mountain areas. Increasing levels of heavier congeners were found in higher altitude sites, although the lighter congeners were the main contributors to the total amount, suggesting that less volatile congeners seem to become enriched easier than those more volatile at higher altitudes in this region.
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| 4. |
- Wang, Yawei, et al.
(författare)
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Effect of municipal sewage treatment plant effluent on bioaccumulation of polychlorinated biphenyls and polybrominated diphenyl ethers in the recipient water
- 2007
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Ingår i: Environmental Science and Technology. - : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 41:17, s. 6026-6032
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Tidskriftsartikel (refereegranskat)abstract
- Water, sediment, and aquatic species including plankton, fish, and turtles were collected from a small lake in Beijing, which receives effluent discharged from a large sewage treatment plant (STP). The samples were examined to investigate polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) releases from a STP and their distributions in the lake. The accumulations of ∑12PBDEs and BDE-209 in the sediment were 62.3 and 1150 ng/cm2, respectively, while that of ∑PCBs was 99.3 ng/cm2. BDE-209 was detected in more than 50% of the aquatic species. A strong linear correlation (R2 = 0.92) was found between ∑12PBDEs and ∑PCBs levels in aquatic species but not in sediments. The different PBDE congener profiles in sediments and biota samples suggest metabolic debromination in the sampled fish. Bioaccumulations of PBDEs and PCBs were found in aquatic species.The logarithm bioaccumulation factor (BAF) decreases with the number of bromines in PBDEs molecules, while the log BAF versus the number of chlorines in PCBs appears to be parabolic. Biomagnifications of these compounds were not obvious in the food web by analysis of the relationship between ∑12PBDEs or ∑PCBs levels and the trophic level of aquatic biota species.
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| 5. |
- Wang, Yawei, et al.
(författare)
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Selection of bioindicators of polybrominated diphenyl ethers, polychlorinated biphenyls, and organochlorine pesticides in mollusks in the Chinese Bohai Sea
- 2008
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Ingår i: Environmental Science and Technology. - : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 42:19, s. 7159-7165
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Tidskriftsartikel (refereegranskat)abstract
- Mollusks, including bivalve and gastropod samples, were collected in the summer of 2006 and 2007 to evaluate the spatial patterns of organochlorine pesticides (OCPs), polychlorinated biphenyl (PCBs), and polybrominated biphenyl ethers (PBDEs) in the coastal water of the Chinese Bohai Sea. Seven species of mollusks, including Rapana venosa (Rap), Neverita didyma (Nev), Scapharca subcrenata (Sca), Mytilus edulis (Blue mussel, Myt), Amusium (Amu), Meretix meretrix (Mer), and Crassostrea talienwhanensis (Oyster, Ost) were investigated to select appropriate bioindicators. Compared with other species, Ost and Myt possess higher lipid contents and have higher concentrations of OCPs and PBDEs. Multivariate linear regression analysis revealed that the most influential factor on the contaminant concentrations in mollusks is the trophic level (TL), followed by the lipid contents. Concentrations of OCPs, PCBs, and PBDEs correlated negatively with the TL of the selected mollusks. Results of principal component and correlation analyses suggest that Ost and Myt can be used as potential bioindicators of pollution by OCPs, PCBs, and PBDEs of the Chinese Bohai Sea.
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| 6. |
- Elsik, Christine G., et al.
(författare)
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The Genome Sequence of Taurine Cattle : A Window to Ruminant Biology and Evolution
- 2009
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 324:5926, s. 522-528
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Tidskriftsartikel (refereegranskat)abstract
- To understand the biology and evolution of ruminants, the cattle genome was sequenced to about sevenfold coverage. The cattle genome contains a minimum of 22,000 genes, with a core set of 14,345 orthologs shared among seven mammalian species of which 1217 are absent or undetected in noneutherian (marsupial or monotreme) genomes. Cattle-specific evolutionary breakpoint regions in chromosomes have a higher density of segmental duplications, enrichment of repetitive elements, and species-specific variations in genes associated with lactation and immune responsiveness. Genes involved in metabolism are generally highly conserved, although five metabolic genes are deleted or extensively diverged from their human orthologs. The cattle genome sequence thus provides a resource for understanding mammalian evolution and accelerating livestock genetic improvement for milk and meat production.
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| 7. |
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| 8. |
- Sodergren, Erica, et al.
(författare)
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The genome of the sea urchin Strongylocentrotus purpuratus.
- 2006
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 1095-9203 .- 0036-8075. ; 314:5801, s. 941-52
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Tidskriftsartikel (refereegranskat)abstract
- We report the sequence and analysis of the 814-megabase genome of the sea urchin Strongylocentrotus purpuratus, a model for developmental and systems biology. The sequencing strategy combined whole-genome shotgun and bacterial artificial chromosome (BAC) sequences. This use of BAC clones, aided by a pooling strategy, overcame difficulties associated with high heterozygosity of the genome. The genome encodes about 23,300 genes, including many previously thought to be vertebrate innovations or known only outside the deuterostomes. This echinoderm genome provides an evolutionary outgroup for the chordates and yields insights into the evolution of deuterostomes.
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| 9. |
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| 10. |
- Zhao, Peng, et al.
(författare)
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Lentiviral vector mediated siRNA knock-down of hTERT results in diminished capacity in invasiveness and in vivo growth of human glioma cells in a telomere length-independent manner
- 2007
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Ingår i: International Journal of Oncology. - 1019-6439. ; 31:2, s. 361-368
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Tidskriftsartikel (refereegranskat)abstract
- Glioma cells are characterized by their invasiveness and resistance against conventional therapeutics. Telomerase activity has been suggested to be an important target for glioma treatment. Here we assessed the anticancer effects and its potential mechanisms of lentiviral vector mediated siRNA knock-down of the human telomerase reverse transcriptase (hTERT) in U87MG human glioblastoma cells. Stable expression of anti-hTERT siRNA reduced the hTERT expression and TRAP assay telomerase activity to barely detectable levels. Injection of lentiviral vectors encoding anti-hTERT siRNA significantly inhibited the growth of preestablished macroscopic xenograft tumors, which was in contrast to the finding that no obvious effects on cell growth, cell cycle progression and telomere length were observed in anti-hTERT siRNA expressing U87MG cells during short-term in vitro cultures. The in vivo glioma growth inhibition effect was already evident in the period coincided with no detectable telomere length changes, suggesting that hTERT inhibition may hinder glioma cell growth in a telomere length-independent manner. Importantly, transwell migration assay showed profound inhibitory effect on the invasive capacity of U87MG cells following short-term anti-hTERT siRNA expression. Thus, efficient knock-down of hTERT can inhibit glioma cell proliferation and migration prior to its effect on telomere length.
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