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| 2. |
- Bard-Chapeau, Emilie A, et al.
(författare)
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Transposon mutagenesis identifies genes driving hepatocellular carcinoma in a chronic hepatitis B mouse model.
- 2014
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Ingår i: Nature Genetics. - : Springer Science and Business Media LLC. - 1061-4036 .- 1546-1718. ; 46:1
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Tidskriftsartikel (refereegranskat)abstract
- The most common risk factor for developing hepatocellular carcinoma (HCC) is chronic infection with hepatitis B virus (HBV). To better understand the evolutionary forces driving HCC, we performed a near-saturating transposon mutagenesis screen in a mouse HBV model of HCC. This screen identified 21 candidate early stage drivers and a very large number (2,860) of candidate later stage drivers that were enriched for genes that are mutated, deregulated or functioning in signaling pathways important for human HCC, with a striking 1,199 genes being linked to cellular metabolic processes. Our study provides a comprehensive overview of the genetic landscape of HCC.
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| 4. |
- Artesani, A., et al.
(författare)
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Monitoring metal ion leaching in oil-ZnO paint systems with a paramagnetic probe
- 2019
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Ingår i: Microchemical Journal. - : Elsevier BV. - 0026-265X. ; 151
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Tidskriftsartikel (refereegranskat)abstract
- Zinc oxide (ZnO), used as a pigment since the 19th C., is highly reactive when mixed with drying oils. Indeed, the combination of metal-based pigments and drying oils may react to form metal complexes in paint, which may lead to the aggregation of metal carboxylates or soaps. Whereas the mechanism and chemistry behind metal soap formation has been studied in depth, little research has focused on the changes that affect the inorganic pigment particles. In this work, we concentrate on the first phase of these reactions and monitor the evolution of an oil-ZnO paint system through Electron Paramagnetic Resonance (EPR) spectroscopy. By employing CuII as a paramagnetic probe, the progression of metal ion leaching from ZnO is followed through the switching of CuII from a silent tetrahedral coordination in ZnO bulk to an EPR active pseudo-octahedral coordination. Complementarily, the effective concentration of dissolved or extracted Zn and Cu is quantified through Inductively Coupled Plasma-Optical Emission Spectrometry (ICP-OES). The experiment probes the spontaneous metal ion release in oil-based paint films and demonstrates that the kinetics of this phenomenon proceeds with a very steep increase in the first hours after mixing. This is followed by the saturation of the grow rate after a few days that we ascribe to the passivation of the ZnO pigment surface by carboxylate groups, which hinders the further leaching of metal ions, leading to a steady-state before the complete hardening or oxidation of the paint film. © 2019
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| 5. |
- Black, R. R., et al.
(författare)
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Emission factors for PCDD/PCDF and dl-PCB from open burning of biomass
- 2012
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Ingår i: Environment International. - : Elsevier. - 0160-4120 .- 1873-6750. ; 38:1, s. 62-66
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Tidskriftsartikel (refereegranskat)abstract
- The Stockholm Convention on Persistent Organic Pollutants includes in its aims the minimisation of unintentional releases of polychlorinated dibenzo-dioxins and dibenzofurans (PCDD/PCDF) and dioxin like PCB (dl-PCB) to the environment Development and implementation of policies to achieve this aim require accurate national inventories of releases of PCDD/PCDF/dl-PCB. To support this objective, the Conference of Parties established a process to review and update the UNEP Standardized Toolkit for Identification and Quantification of Dioxin and Furan Releases. An assessment of all emission inventories was that for many countries open burning of biomass and waste was identified as the major source of PCDD/PCDF releases. However, the experimental data underpinning the release estimates used were limited in number and, consequently, confidence in the accuracy of the emissions predictions was low. There has been significant progress in measurement technology since the last edition of the Toolkit in 2005. In this paper we reassess published emission factors for release of PCDD/PCDF and dl-PCB to land and air.In total, four types of biomass and 111 emission factors were assessed. It was found that there are no systematic differences in emission factors apparent between biomass types or fire classes. The data set is best described by a lognormal distribution. The geometric mean emission factors (EFs) for releases of PCDD/PCDF to air for the four biomass classes used in the Toolkit (sugarcane, cereal crops, forest and savannah/grass) are 1.6 mu g TEQ(t fuel)(-1), 0.49 mu g TEQ(t fuel)(-1), 1.0 mu g TEQ(t fuel)(-1) and 0.4 mu g TEQ(t fuel)(-1), respectively. Corresponding EFs for release of PCDD/PCDF to land are 3.0 ng TEQ (kg ash)(-1), 1.1 ng TEQ (kg ash)(-1), 1.1 ng TEQ (kg ash)(-1) and 0.67 ng TEQ (kg ash)(-1). There are now also sufficient published data available to evaluate EFs for dl-PCB release to air for sugarcane, forest and grass/savannah; these are 0.03 mu g TEQ (t fuel)(-1), 0.09 mu g TEQ (t fuel)(-1) and 0.01 mu g TEQ (t fuel)(-1), respectively. The average EF for dl-PCB release to land is 0.19 ng TEQ (kg ash)(-1). Application of these EFs to national emissions of PCDD/PCDF for global estimates from open burning will lower previous estimates of PCDD/PCDF releases to air and to land by 85% and 90%, respectively. For some countries, the ranking of their major sources will be changed and open burning of biomass will become less significant than previously concluded.
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| 6. |
- Black, R. R., et al.
(författare)
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Emissions of PCDD and PCDF from combustion of forest fuels and sugarcane : A comparison between field measurements and simulations in a laboratory burn facility
- 2011
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Ingår i: Chemosphere. - : Elsevier. - 0045-6535 .- 1879-1298. ; 83:10, s. 1331-1338
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Tidskriftsartikel (refereegranskat)abstract
- Release of PCDD and PCDF from biomass combustion such as forest and agricultural crop fires has been nominated as an important source for these chemicals despite minimal characterisation. Available emission factors that have been experimentally determined in laboratory and field experiments vary by several orders of magnitude from <0.51 mu g TEQ(t fuel consumed)(-1) to >1001 mu g TEQ(t fuel consumed)(-1). The aim of this study was to evaluate the effect of experimental methods on the emission factor.A portable field sampler was used to measure PCDD/PCDF emissions from forest fires and the same fuel when burnt over a brick hearth to eliminate potential soil effects. A laboratory burn facility was used to sample emissions from the same fuels. There was very good agreement in emission factors to air (EF(Air)) for forest fuel (Duke Forest, NC) of 0.52 (range: 0.40-0.79), 0.59 (range: 0.18-1.2) and 0.75 (range: 0.27-1.2) mu g TEQ(WHO2005) (t fuel consumed)(-1) for the in-field, over a brick hearth, and burn facility experiments, respectively. Similarly, experiments with sugarcane showed very good agreement with EFAir of 1.1 (range: 0.40-2.2), 1.5 (range: 0.84-2.2) and 1.7 (range: 0.34-4.4) mu g TEQ (t fuel consumed)(-1) for in-field, over a brick hearth, open field and burn facility experiments respectively. Field sampling and laboratory simulations were in good agreement, and no significant changes in emissions of PCDD/PCDF could be attributed to fuel storage and transport to laboratory test facilities.
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| 7. |
- Solorzano-Ochoa, Gustavo, et al.
(författare)
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Open burning of household waste : Effect of experimental condition on combustion quality and emission of PCDD, PCDF and PCB
- 2012
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Ingår i: Chemosphere. - : Elsevier. - 0045-6535 .- 1879-1298. ; 87:9, s. 1003-1008
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Tidskriftsartikel (refereegranskat)abstract
- Open burning for waste disposal is, in many countries, the dominant source of polychlorinated dibenzo-dioxins, dibenzofurans and biphenyls (PCDD/PCDF/PCB) release to the environment. To generate emission factors for open burning, experimental pile burns of about 100 kg of household waste were conducted with emissions sampling. From these experiments and others conducted by the same authors it is found that less compaction of waste or active mixing during the fire - "stirring" - promotes better combustion (as evidenced by lower CO/CO2 ratio) and reduces emissions of PCDD/PCDF/PCB; an intuitive but previously undemonstrated result. These experiments also support previous results suggesting PCDD/PCDF/PCB generation in open burning - while still highly variable - tends to be greater in the later (smoldering) phases of burning when the CO/CO2 ratio increases.
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