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- Morozova-Roche, Ludmilla, et al.
(författare)
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Fibrillation of Carrier Protein Albebetin and Its Biologically Active Constructs. Multiple Oligomeric Intermediates and Pathways
- 2004
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Ingår i: Biochemistry. - : American Chemical Society (ACS). - 0006-2960 .- 1520-4995. ; 43:30, s. 9610-9619
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Tidskriftsartikel (refereegranskat)abstract
- We showed that the genetically engineered carrier-protein albebetin and its biologically active constructs with interferon-2 octapeptide LKEKKYSP or differentiation factor hexapeptide TGENHR are inherently highly amyloidogenic at physiological pH. The kinetics of fibrillation were monitored by thioflavine-T (ThT) binding and the morphological changes by atomic force microscopy. Fibrillation proceeds via multiple pathways and includes a hierarchy of amyloid structures ranging from oligomers to protofilaments and fibrils. Comparative height and volume microscopic measurements allowed us to identify two distinct types of oligomeric intermediates: pivotal oligomers ca. 1.2 nm in height comprised of 10-12 monomers and on-pathway amyloid-competent oligomers ca. 2 nm in height constituted of 26-30 molecules. The former assemble into chains and rings with "bead-on-string morphology", in which a "bead" corresponds to an individual oligomer. Once formed, the rings and chains remain in solution simultaneously with fibrils. The latter give rise to protofilaments and fibrils, and their formation is concomitant with an increasing level of ThT binding. The amyloid nature of filamentous structures was confirmed by a pronounced ThT and Congo red binding and -sheet-rich far-UV circular dichroism. We suggest that transformation of the pivotal oligomers into the amyloid-prone ones is a limiting stage in amyloid assembly. Peptides, either fused to albebetin or added into solution, and an increased ionic strength promote fibrillation of albebetin (net charge of -12) by counterbalancing critical electrostatic repulsions. This finding demonstrates that the fibrillation of newly designed polypeptide-based products can produce multimeric amyloid species with a potentially "new" functionality, raising questions about their safety.
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- Brus, E, et al.
(författare)
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Bed Material Consumption in Biomass Fired Fluidised Bed Boilers Due to Risk of Bed Agglomeration : Coating Formation and Possibilities for Regeneration
- 2003
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Ingår i: Industrial Combustion. - 2075-3071. ; :2, s. 1-12
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Tidskriftsartikel (refereegranskat)abstract
- Previous studies have shown that many biomass fuels result in critical agglomeration temperatures in the same range as typical operating process temperatures for fluidised beds. As soon as a sufficiently thick coating on the bed particles has been formed, the risk for severe agglomeration and defluidisation is often significant. Frequent bed change is therefore the normally method applied to ensure problem-free operation, but this is associated with additional costs and not sustainable on a long-term basis.The objectives of the present work were therefore to; i) collect full-scale bed material samples to determine coating characteristics and growth as functions of time; ii) estimate the critical coating thickness/age of the bed particles by SEM/EDS analysis and experimental determinate the agglomeration temperatures for the collected bed material; iii) experimentally evaluate if size fractionation and mechanical treatment could be used to reduce the bed material consumption.Bed material samples from two bubbling and two circulating full-scale fluidised bed boilers, with previous documented bed agglomeration problems, were collected. All plants used typical wood-based fuel mixtures. The coating formation rates on the bed particles were found to be significant, with an initial rate of some mm per day, but decreasing with time. The coating material was generally found to consist of Ca- and Mg-silicates as well as P, although the form in which it was present was not determined. The experimentally determined fuel specific agglomeration temperatures were found to agree well with the corresponding critical temperatures for the full-scale bed materials, as well as with the experiences reported by the different plant operators. The critical coating thickness was found to be relatively thin (
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- Lisspers, Jan, et al.
(författare)
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Long-term effects of lifestyle behaviour change intervention after PTCA: Effects on lifestyle, progression of CAD, and on cardiac events. : The VI Nordic Congress on Cardiac Rehabilitation, June 14th-16th 2002, Reykjavik, Iceland.
- 2002
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Föredrag vid The VI Nordic Congress on Cardiac Rehabilitation, June 14th-16th 2002, Reykjavik, Iceland (Belönades med titeln: First price for an outstanding oral presentation at the VI Nordic Congress on Cardiac Rehabilitation, Reykjavik, 2002).
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