| 1. |
- Janzen, Viktor, et al.
(författare)
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Hematopoietic stem cell responsiveness to exogenous signals is limited by Caspase-3
- 2008
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Ingår i: Cell Stem Cell. - : Elsevier BV. - 1934-5909. ; 2:6, s. 584-594
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Tidskriftsartikel (refereegranskat)abstract
- Limited responsiveness to inflammatory cytokines is a feature of adult hematopoietic stem cells and contributes to the relative quiescence and durability of the stem cell population in vivo. Here we report that the executioner Caspase, Caspase-3, unexpectedly participates in that process. Mice deficient in Caspase-3 had increased numbers of immunophenotypic long-term repopulating stem cells in association with multiple functional changes, most prominently cell cycling. Though these changes were cell autonomous, they reflected altered activation by exogenous signals. Caspase-3(-/-) cells exhibited cell type-specific changes in phosphorylated members of the Ras-Raf-MEK-ERK pathway in response to specific cytokines, while notably, members of other pathways, such as pSTAT3, pSTAT5, pAKT, pp38 MAPK, pSmad2, and pSmad3, were unaffected. Caspase-3 contributes to stem cell quiescence, dampening specific signaling events and thereby cell responsiveness to microenvironmental stimuli.
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| 2. |
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| 3. |
- Karlsson, Lovisa, 1989-, et al.
(författare)
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Release of metals from unprocessed and processed black shale due to natural weathering
- 2013
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Ingår i: Reliable Mine Water Technology. Volume 1. - Colorado, USA : IMWA. - 9780615793856 ; , s. 391-397
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Konferensbidrag (refereegranskat)abstract
- Black shale was mined and processed for recovery of hydrocarbons in Kvarntorp, some 200 km SW of Stockholm, Sweden, during 1942–66. Remains from the mining period is a deposit with 40 Mm³ of crushed shale residues: Unprocessed 3ne-grained shale as well as processed shale. The deposit is still hot; oxidation of sulphides as well as burning of hydrocarbons are still in progress some 50 years a1er closure. Weathering of the shale leads to releases of metal-rich leachates which will increase with time. The release of metals from pristine shale as well as weathered shale (exposed to the atmosphere for 50 years) and two di2erent processed shale residues have been studied using water of di2erent pH as leaching solution, to simulate extreme pH-variations in environmental waters: 3.0 (determined by oxidation of iron sulphides), 5.5 (bu2ered by carbon dioxide), 8.5 (bu2ered by calcite) and 12.5 (bu2ered by calcium hydroxide). Extraction of cationic elements was substantial (several percent of the total content) for Ca and Mg, as well as Ni, Co and U at pH 3, and very high (up to 50–60 %) for anionic elements (V, Mo, As) at pH 12.5. Especially the high-temperature processed shale would be a potential source for As and Mo at high pH. The pH-dependence of the weathering processes should be considered when future remediation (or metal recovery) processes and strategies are designed.
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| 4. |
- Karlsson, Stefan, 1957-, et al.
(författare)
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Water quality in a black shale mining area : effects of pH and natural organic acids on weathering and subsequent metal releases
- 2014
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Ingår i: An Interdisciplinary Response to Mine Water Challenges. - : China University of Mining and Techno logy Press. - 9787564624378 ; , s. 136-136
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Konferensbidrag (refereegranskat)abstract
- Mining of black shale (alum shale) of Late Cambrium age for the extraction of alum started in the early 17th century in Sweden, and in the late 19th century there was an extensive use of shale, with its high content of organic carbon, as fuel in lime-burning processes. Full-scale recovery of hydrocarbons from shale took place in Kvarntorp during 1942-66, and recovery of uranium in Ranstad during 1965-76. Remains from the historic mining and processing of black shale are some 50 major deposits with processed and unprocessed shale residues, as well as water-filled pits, at the former mining sites. There are also large areas covered with crushed shale, e.g. as road filling material. Studies of the weathering of shale due to exposure to the atmosphere and water with pH within the natural range indicate a high leachability of cationic elements at low pH, as well as anionic elements at high pH. The presence of organic complexing acids of natural origin (microbial exudates and humic acids) may give an enhanced leaching, particularly at pH above 8, when hydroxy-groups would constitute active metal binding sites. Results from studies of weathering and leaching of processed and unprocessed black shale are presented, as well as the effects on the water quality observed at former mining sites and related environmental impact.
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| 5. |
- Sjöberg, Viktor, et al.
(författare)
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Bioleaching of shale : impact of carbon source
- 2011
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Ingår i: The new uranium mining boom. - Berlin, Heidelberg : Springer Berlin/Heidelberg. - 9783642221217 ; , s. 449-454
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Konferensbidrag (refereegranskat)abstract
- Bioleaching is often used for processing low-grade shale feedstock and the microbial community used for that purpose is supplied with nutrients such as sugar and/or Fe2+. In the present study, the leaching efficiency was tested when crushed weathered shale was mixed with aspen wood shavings and kept moist, at the mixtures field capacity. The purpose was to investigate whether a more complex carbon source and a lower content of water may be a feasible way of lowering the cost for bioleaching. After 56 days of incubation the amount of uranium mobilized from the shale reached some 1.7% with a minimum of effort and cost.
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| 6. |
- Allard, Bert, 1945-, et al.
(författare)
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Black shale : a biogeochemical archive
- 2014
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Ingår i: Sedimentary Pore Space Cementation: Role of Microbes. ; , s. 6-
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Konferensbidrag (refereegranskat)
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| 7. |
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| 8. |
- Allard, Bert, 1945-, et al.
(författare)
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Metal Exchangeability in the REE-Enriched Biogenic Mn Oxide Birnessite from Ytterby, Sweden
- 2023
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Ingår i: Minerals. - : MDPI. - 2075-163X. ; 13:8
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Tidskriftsartikel (refereegranskat)abstract
- A black substance exuding from fractures was observed in 2012 in Ytterby mine, Sweden, and identified in 2017 as birnessite with the composition Mx[Mn(III,IV)](2)O-4 center dot(H2O)n. M is usually calcium and sodium, with x around 0.5. The Ytterby birnessite is unique, with M being calcium, magnesium, and also rare earth elements (REEs) constituting up to 2% of the total metal content. The biogenic origin of the birnessite was established in 2018. Analysis of the microbial processes leading to the birnessite formation and the REE enrichment has continued since then. The process is fast and dynamic, as indicated by the depletion of manganese and of REE and other metals in the fracture water during the passage over the precipitation zone in the mine tunnel. Studies of the exchangeability of metals in the structure are the main objective of the present program. Exposure to solutions of sodium, calcium, lanthanum, and iron led to exchanges and altered distribution of the metals in the birnessite, however, generating phases with almost identical structures after the exchanges, and no new mineral phases were detected. Exchangeability was more efficient for trivalent elements (REE) over divalent (calcium) and monovalent (sodium) elements of a similar size (ionic radii 90-100 pm).
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