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- Kopf, Sabrina, et al.
(författare)
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Production and Characterization of Melt-Spun Poly(3-hydroxybutyrate)/Poly(3-hydroxybutyrate-co-4-hydroxybutyrate) Blend Monofilaments
- 2024
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Ingår i: ACS Omega. - : American Chemical Society. - 2470-1343.
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Tidskriftsartikel (refereegranskat)abstract
- We investigated the melt-spinning potential of a poly(3-hydroxybutyrate)/poly(3-hydroxybutyrate-co-4-hydroxybutyrate) blend using a piston spinning machine with two different spinneret diameters (0.2 and 0.5 mm). Results from the differential scanning calorimetry, dynamic mechanical thermal analysis, and tensile testing showed distinct filament properties depending on the monofilaments’ cross-sectional area. Finer filaments possessed different melting behaviors compared to the coarser filaments and the neat polymer, indicating the formation of a different type of polymer crystal. Additionally, the mechanical properties of the finer filament (tensile strength: 21.5 MPa and elongation at break: 341%) differed markedly from the coarser filament (tensile strength: 11.7 MPa, elongation at break: 12.3%). The hydrolytic stability of the filaments was evaluated for 7 weeks in a phosphate-buffered saline solution and showed a considerably reduced elongation at break of the thinner filaments. Overall, the results indicate considerable potential for further filament improvements to facilitate textile processing.
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| 3. |
- Pettersson, B. M. Fredrik, et al.
(författare)
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Comparative Sigma Factor-mRNA Levels in Mycobacterium marinum under Stress Conditions and during Host Infection
- 2015
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Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 10:10
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Tidskriftsartikel (refereegranskat)abstract
- We have used RNASeq and qRT-PCR to study mRNA levels for all s-factors in different Mycobacterium marinum strains under various growth and stress conditions. We also studied their levels in M. marinum from infected fish and mosquito larvae. The annotated s-factors were expressed and transcripts varied in relation to growth and stress conditions. Some were highly abundant such as sigA, sigB, sigC, sigD, sigE and sigH while others were not. The s-factor mRNA profiles were similar after heat stress, during infection of fish and mosquito larvae. The similarity also applies to some of the known heat shock genes such as the a-crystallin gene. Therefore, it seems probable that the physiological state of M. marinum is similar when exposed to these different conditions. Moreover, the mosquito larvae data suggest that this is the state that the fish encounter when infected, at least with respect to s-factor mRNA levels. Comparative genomic analysis of s-factor gene localizations in three M. marinum strains and Mycobacterium tuberculosis H37Rv revealed chromosomal rearrangements that changed the localization of especially sigA, sigB, sigD, sigE, sigF and sigJ after the divergence of these two species. This may explain the variation in species-specific expression upon exposure to different growth conditions.
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