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| 2. |
- Camsund, Daniel, et al.
(författare)
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A HupS-GFP fusion protein demonstrates a heterocyst-specific localization of the uptake hydrogenase in Nostoc punctiforme
- 2011
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Ingår i: FEMS Microbiology Letters. - : John Wiley & Sons. - 0378-1097 .- 1574-6968. ; 316:2, s. 152-159
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Tidskriftsartikel (refereegranskat)abstract
- All diazotrophic filamentous cyanobacteria contain an uptake hydrogenase that is involved in the reoxidation of H-2 produced during N-2-fixation. In Nostoc punctiforme ATCC 29133, N-2-fixation takes place in the microaerobic heterocysts, catalysed by a nitrogenase. Although the function of the uptake hydrogenase may be closely connected to that of nitrogenase, the localization in cyanobacteria has been under debate. Moreover, the subcellular localization is not understood. To investigate the cellular and subcellular localization of the uptake hydrogenase in N. punctiforme, a reporter construct consisting of the green fluorescent protein (GFP) translationally fused to HupS, within the complete hupSL operon, was constructed and transferred into N. punctiforme on a self-replicative vector by electroporation. Expression of the complete HupS-GFP fusion protein was confirmed by Western blotting using GFP antibodies. The N. punctiforme culture expressing HupS-GFP was examined using laser scanning confocal microscopy, and fluorescence was exclusively detected in the heterocysts. Furthermore, the fluorescence in mature heterocysts was localized to several small or fewer large clusters, which indicates a specificity of the subcellular localization of the uptake hydrogenase.
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| 3. |
- Nöjd, Sofi, et al.
(författare)
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Deswelling behaviour of ionic microgel particles from low to ultra-high densities
- 2018
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Ingår i: Soft Matter. - : Royal Society of Chemistry (RSC). - 1744-683X .- 1744-6848. ; 14:20, s. 4150-4159
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Tidskriftsartikel (refereegranskat)abstract
- The swelling of ionic microgel particles is investigated at a wide range of concentrations using a combination of light, X-ray and neutron scattering techniques. We employ a zero-average contrast approach for small-angle neutron scattering experiments, which enables a direct determination of the form factor at high concentrations. The observed particle size initially decreases strongly with the particle concentration in the dilute regime but approaches a constant value at intermediate concentrations. This is followed by a further deswelling at high concentrations above particle overlap. Theory and experiments point at a pivotal contribution of dangling polymer ends to the strong variation in size of ionic microgels, which presents itself mainly through the hydrodynamics properties of the system.
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| 4. |
- O'Connell, Adam, et al.
(författare)
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The structure and dynamics of locust bean gum in aqueous solution
- 2023
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Ingår i: Food Hydrocolloids. - : Elsevier BV. - 0268-005X. ; 138
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Tidskriftsartikel (refereegranskat)abstract
- Locust bean gum (LBG) is an industrially important polysaccharide used widely in food, cosmetics, textiles, and biopharmaceutical applications, where understanding its solution behaviour is important for formulation design. To address this, we investigate the structure and dynamics of LBG in aqueous solution using steady state shear rheology, static light scattering (SLS), ultra-small-angle light scattering (USALS), and dynamic light scattering (DLS). We find that steady state shear rheology mainly probes the well-dispersed LBG fraction, whereas the scattering response is dominated by supramolecular LBG aggregates. We identify three viscosity-concentration regimes (dilute, semidilute unentangled, and semidilute entangled), with scaling behaviour largely consistent with predictions for neutral flexible polymers. SLS and USALS provide evidence for the existence of two separate populations of aggregated structures, where SLS mainly probes the internal structure of the smaller aggregate population. The solution dynamics are dominated by a ‘slow’ decay mode, which is consistent with Zimm dynamics and attributed to relaxations within the aggregates. In dilute solutions, the apparent viscosity associated with this mode is greater than the solution viscosity, but the two converge as concentration is increased. An additional ‘fast’ mode is observed within the semidilute range, associated with the dispersed polymer fraction, and attributed to cooperative diffusion. Our study provides comprehensive insight into the structure and dynamics of aqueous LBG solutions—paving the way for a greater fundamental understanding of galactomannans in solution, and for increased control over LBG-based formulations of industrial interest.
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| 5. |
- Pal, Antara, et al.
(författare)
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Extending depolarized DLS measurements to turbid samples
- 2022
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Ingår i: Journal of Colloid and Interface Science. - : Elsevier BV. - 0021-9797. ; 627, s. 1-9
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Tidskriftsartikel (refereegranskat)abstract
- The application of dynamic light scattering to soft matter systems has strongly profited from advanced approaches such as the so-called modulated 3D cross correlation technique (Mod3D-DLS) that suppress contributions from multiple scattering, and can therefore be used for the characterization of turbid samples. Here we now extend the possibilities of this technique to allow for depolarized light scattering (Mod3D-DDLS) and thus obtain information on both translational and rotational diffusion, which is important for the characterization of anisotropic particles. We describe the required optical design and test the performance of the approach for increasingly turbid samples using well defined anisotropic colloidal models systems. Our measurements demonstrate that 3D-DDLS experiments can be performed successfully for samples with a reduced transmission due to multiple scattering as low as 1%. We compare the results from this approach with those obtained by standard DDLS experiments, and point out the importance of using an appropriate optical design when performing depolarized dynamic light scattering experiments with turbid systems.
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| 6. |
- Pal, Antara, et al.
(författare)
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Structure and dynamics of dense colloidal ellipsoids at the nearest-neighbor length scale
- 2021
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Ingår i: Physical Review Research. - 2643-1564. ; 3:2
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Tidskriftsartikel (refereegranskat)abstract
- Anisotropic particles are known to exhibit a richer and more complex phase behavior in comparison to their spherical counterpart. While the majority of the existing studies address structural properties, the dynamic behavior of anisotropic particles is a relatively lesser explored avenue. Using multispeckle ultra-small-angle x-ray photon correlation spectroscopy (USA-XPCS), we have carried out a systematic investigation of the structural and dynamic properties of colloidal ellipsoids at the nearest-neighbor length scale. The USA-XPCS measurements have allowed us to probe, as a function of the volume fraction, the q-dependent effective structure factor, Seff(q), along with the effective long time diffusion coefficient, Deff(q), for this anisotropic system. Our results indicate a scaling behavior of Deff(q) with 1/Seff(q) from which we have estimated the effective amplitude function Aeff(q), which can be directly related to the effective hydrodynamic function Heff(q). Aeff(q) shows a similar q dependence to that of S(q). Our investigation also allows for the precise determination of the volume fraction corresponding to the arrest transition.
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| 7. |
- Sparrman, Anna, 1965-, et al.
(författare)
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Child Studies Multiple : Collaborative play for thinking through theories and methods
- 2023
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Ingår i: Culture Unbound. - : Linköping University Electronic Press. - 2000-1525. ; 15:1
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Tidskriftsartikel (refereegranskat)abstract
- This text is an exploration of collaborative thinking and writing through theories, methods, and experiences on the topic of the child, children, and childhood. It is a collaborative written text (with 32 authors) that sprang out of the experimental workshop Child Studies Multiple. The workshop and this text are about daring to stay with mess, “un-closure” , and uncertainty in order to investigate the (e)motions and complexities of being either a child or a researcher. The theoretical and methodological processes presented here offer an opportunity to shake the ground on which individual researchers stand by raising questions about scientific inspiration, theoretical and methodological productivity, and thinking through focusing on process, play, and collaboration. The effect of this is a questioning of the singular academic ‘I’ by exploring and showing what a plural ‘I’ can look like. It is about what the multiplicity of voice can offer research in a highly individualistic time. The article allows the reader to follow and watch the unconventional trial-and-error path of the ongoing-ness of exploring theories and methods together as a research community via methods of drama, palimpsest, and fictionary.
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| 8. |
- Winther, Jeanete F., et al.
(författare)
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Childhood cancer survivor cohorts in Europe
- 2015
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Ingår i: Acta Oncologica. - 1651-226X. ; 54:5, s. 655-668
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Forskningsöversikt (refereegranskat)abstract
- With the advent of multimodality therapy, the overall five-year survival rate from childhood cancer has improved considerably now exceeding 80% in developed European countries. This growing cohort of survivors, with many years of life ahead of them, has raised the necessity for knowledge concerning the risks of adverse long-term sequelae of the life-saving treatments in order to provide optimal screening and care and to identify and provide adequate interventions. Childhood cancer survivor cohorts in Europe. Considerable advantages exist to study late effects in individuals treated for childhood cancer in a European context, including the complementary advantages of large population-based cancer registries and the unrivalled opportunities to study lifetime risks, together with rich and detailed hospital-based cohorts which fill many of the gaps left by the large-scale population-based studies, such as sparse treatment information. Several large national cohorts have been established within Europe to study late effects in individuals treated for childhood cancer including the Nordic Adult Life after Childhood Cancer in Scandinavia study (ALiCCS), the British Childhood Cancer Survivor Study (BCCSS), the Dutch Childhood Oncology Group (DCOG) LATER study, and the Swiss Childhood Cancer Survivor Study (SCCSS). Furthermore, there are other large cohorts, which may eventually become national in scope including the French Childhood Cancer Survivor Study (FCCSS), the French Childhood Cancer Survivor Study for Leukaemia (LEA), and the Italian Study on off-therapy Childhood Cancer Survivors (OTR). In recent years significant steps have been taken to extend these national studies into a larger pan-European context through the establishment of two large consortia - PanCareSurFup and PanCareLIFE. The purpose of this paper is to present an overview of the current large, national and pan-European studies of late effects after childhood cancer. This overview will highlight the strong cooperation across Europe, in particular the EU-funded collaborative research projects PanCareSurFup and PanCareLIFE. Overall goal. The overall goal of these large cohort studies is to provide every European childhood cancer survivor with better care and better long-term health so that they reach their full potential, and to the degree possible, enjoy the same quality of life and opportunities as their peers.
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| 9. |
- Agervald, Åsa, et al.
(författare)
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Transcription of the extended hyp-operon in Nostoc sp. strain PCC 7120
- 2008
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Ingår i: BMC Microbiology. - : Springer Science and Business Media LLC. - 1471-2180. ; 8, s. 69-
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Tidskriftsartikel (refereegranskat)abstract
- Background: The maturation of hydrogenases into active enzymes is a complex process and e. g. a correctly assembled active site requires the involvement of at least seven proteins, encoded by hypABCDEF and a hydrogenase specific protease, encoded either by hupW or hoxW. The N2fixing cyanobacterium Nostoc sp. strain PCC 7120 may contain both an uptake and a bidirectional hydrogenase. The present study addresses the presence and expression of hypgenes in Nostoc sp. strain PCC 7120. Results: RTPCRs demonstrated that the six hypgenes together with one ORF may be transcribed as a single operon. Transcriptional start points (TSPs) were identified 280 bp upstream from hypF and 445 bp upstream of hypC, respectively, demonstrating the existence of several transcripts. In addition, five upstream ORFs located in between hupSL, encoding the small and large subunits of the uptake hydrogenase, and the hypoperon, and two downstream ORFs from the hypgenes were shown to be part of the same transcript unit. A third TSP was identified 45 bp upstream of asr0689, the first of five ORFs in this operon. The ORFs are annotated as encoding unknown proteins, with the exception of alr0692 which is identified as a NifUlike protein. Orthologues of the four ORFs asr0689alr0692, with a highly conserved genomic arrangement positioned between hupSL, and the hyp genes are found in several other N2fixing cyanobacteria, but are absent in non N2fixing cyanobacteria with only the bidirectional hydrogenase. Short conserved sequences were found in six intergenic regions of the extended hypoperon, appearing between 11 and 79 times in the genome. Conclusion: This study demonstrated that five ORFs upstream of the hypgene cluster are cotranscribed with the hypgenes, and identified three TSPs in the extended hypgene cluster in Nostoc sp. strain PCC 7120. This may indicate a function related to the assembly of a functional uptake hydrogenase, hypothetically in the assembly of the small subunit of the enzyme.
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| 10. |
- Ankerfors, Caroline, et al.
(författare)
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Final Report for the Source-Efficient Paper and Board Making Research Programme Area
- 2018
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- This is the final report for the Innventia/RISE Bioeconomy research programme area “Source-Efficient Paper and Board Making”, which was executed 2015-2017.The overall aim of the Source Efficient Paper and Board Making was to improve the resource efficiency in paper and board production. This was achieved by combining paper chemistry, paper physics and process technology. A particular goal was to reduce raw material consumption through the use of stronger materials or creation of bulk, which are needed to maintain bending stiffness and mechanical properties if the grammage is reduced. The work in the project has been carried out in laboratory scale and in pilot scale using the FEX pilot paper machine and the dynamic flow loop.
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