| 1. |
- Blom, Hans, et al.
(författare)
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Flocculate removal after alkaline lysis in plasmid DNA production.
- 2010
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Ingår i: Vaccine. - : Elsevier BV. - 0264-410X .- 1873-2518. ; 29:1, s. 6-10
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Tidskriftsartikel (refereegranskat)abstract
- Alkaline lysis is the most commonly used method following harvest of bacterial cells for production of plasmid DNA. The method was originally developed for laboratory scale experiments and has shown to be challenging at larger scales. A major problem prior to further downstream processing is the risk of filter clogging without efficient removal of the flocculate that occurs after neutralization. For this purpose we here present a scalable method where the clarification of alkaline lysate is greatly simplified. Through a rapid procedure, involving the addition of ammonium hydrogen carbonate to the neutralized alkaline lysate, the flocculate is lifted to the surface of the solution by the released carbon dioxide and ammonium. After this step a clarified solution can be drained from the bottom of the vessel. The procedure does not impact pH, plasmid DNA concentration or the ratio of open circular to supercoiled plasmid DNA in the solution.
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| 2. |
- Blom, Åsa, 1977-, et al.
(författare)
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Outdoor exposure of untreated Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies L. Karst) wood samples
- 2010
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Ingår i: Wood Material Science & Engineering. - : Taylor & Francis. - 1748-0272 .- 1748-0280. ; 5:3-4, s. 204-210
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Tidskriftsartikel (refereegranskat)abstract
- Untreated Scots pine (Pinus sylvestris) and Norway spruce (Picea abies) samples were exposed above ground in a durability test for six years. The samples consisted of three pieces of wood, 22x95x500 mm, screwed together; two pieces lengthwise with a third piece overlapping. Weight was measured, to calculate moisture content (MC), and samples checked regularly for cracks and fungal growth. Parameters investigated were heartwood/sapwood (pine), annual ring orientation (spruce), stand site, annual ring width and density.Stand site, annual ring width or density had no influence on MC or fungal growth for neither pine nor spruce. Spruce samples with vertical annual rings had lesser amounts of cracks than samples with horizontal annual rings.Regarding pine sapwood samples, they showed high MC and large amount of rot fungi, while heartwood had lower MC and no rot. Most spruce samples were similar to pine heartwood, except from a few samples that had high MC and fungal growth. Those were all sawn from the outer part of the log. Therefore, it can be stated that spruce sawn from the inner part has almost the same properties as pine heartwood while spruce from the outer part of the log has properties similar to pine sapwood.
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