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- Enfors, Sven-Olof, et al.
(författare)
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Physiological responses to mixing in large scale bioreactors
- 2001
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Ingår i: Journal of Biotechnology. - 0168-1656 .- 1873-4863. ; 85:2, s. 175-185
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Tidskriftsartikel (refereegranskat)abstract
- Escherichia coli fed-batch cultivations at 22 m(3) scale were compared to corresponding laboratory scale processes and cultivations using a scale-down reactor furnished with a high-glucose concentration zone to mimic the conditions in a feed zone of the large bioreactor. Formate accumulated in the large reactor, indicating the existence of oxygen limitation zones. It is suggested that the reduced biomass yield at large scale partly is due to repeated production/reassimilation of acetate from overflow metabolism and mixed acid fermentation products due to local moving zones with oxygen limitation. The conditions that generated mixed-acid fermentation in the scale-down reactor also induced a number of stress responses, monitored by analysis of mRNA of selected stress induced genes. The stress responses were relaxed when the cells returned to the substrate limited and oxygen sufficient compartment of the reactor. Corresponding analysis in the large reactor showed that the concentration of mRNA of four stress induced genes was lowest at the sampling port most distant from the feed zone. It is assumed that repeated induction/relaxation of stress responses in a large bioreactor may contribute to altered physiological properties of the cells grown in large-scale bioreactor. Flow cytometric analysis revealed reduced damage with respect to cytoplasmic membrane potential and integrity in cells grown in the dynamic environments of the large scale reactor and the scale-down reactor.
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| 3. |
- Bjorkman, H, et al.
(författare)
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Diamond microchips for fast chromatography of proteins
- 2001
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Ingår i: SENSORS AND ACTUATORS B-CHEMICAL. - 0925-4005. ; 79:1, s. 71-77
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Tidskriftsartikel (refereegranskat)abstract
- As a material for bioanalysis polycrystalline diamond surfaces have attractive characteristics, such as the highest thermal conductivity, optical transparency, chemical inertness, and by choice, electrical insulation or semiconduction. In addition, diamon
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| 8. |
- Hjort, Klas, et al.
(författare)
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Ion track nanostructuring of dielectrics (invited)
- 2003
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Ingår i: 203rd Meeting of the Electrochemical Society, Symp. F1, Science and Technology of Dielectrics in Emerging Fields.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)
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| 9. |
- Hubberten, HW, et al.
(författare)
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The periglacial climate and environment in northern Eurasia during the Last Glaciation
- 2004
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Ingår i: Quaternary Science Reviews. - : Elsevier BV. - 0277-3791. ; 23:11-13, s. 1333-1357
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Forskningsöversikt (refereegranskat)abstract
- This paper summarizes the results of studies of the Late Weichselian periglacial environments carried out in key areas of northern Eurasia by several QUEEN teams (European Science Foundation (ESF) programme: "Quaternary Environment of the Eurasian North"). The palaeoglaciological boundary conditions are defined by geological data on timing and extent of the last glaciation obtained in the course of the EU funded project "Eurasian Ice Sheets". These data prove beyond any doubt, that with the exception of the northwestern fringe of the Taymyr Peninsula, the rest of the Eurasian mainland and Severnaya Zemlya were not affected by the Barents-Kara Sea fee Sheet during the Last Glacial Maximum (LGM). Inversed modelling based on these results shows that a progressive cooling which started around 30 ka BP, caused ice growth in Scandinavia and the northwestern areas of the Barents-Kara Sea shelf, due to a maritime climate with relatively high precipitation along the western flank of the developing ice sheets. In the rest of the Eurasian Arctic extremely low precipitation rates (less than 50 mm yr(-1)), did not allow ice sheet growth in spite of the very cold temperatures. Palaeoclimatic and palaeoenvironmental conditions for the time prior to, during, and after the LGM have been reconstructed for the non-glaciated areas around the LGM ice sheet with the use of faunal and vegetation records, permafrost, eolian sediments, alluvial deposits and other evidences. The changing environment, from interstadial conditions around 30 ka BP to a much colder and drier environment at the culmination of the LGM at 20-15 ka BP, and the beginning of warming around 15 ka BP have been elaborated from the field data, which fits well with the modelling results. (C) 2003 Elsevier Ltd. All rights reserved.
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| 10. |
- Lindström, Åke, et al.
(författare)
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XXX. The best crosses in Ottenby.
- 2000
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Ingår i: Vår Fågelvärld. - 0042-2649. ; 59:7, s. 14-17
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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