| 1. |
- Ahlgren, Kajsa, 1996, et al.
(författare)
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New insights into the protein stabilizing effects of trehalose by comparing with sucrose
- 2023
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Ingår i: Physical Chemistry Chemical Physics. - : Royal Society of Chemistry (RSC). - 1463-9084 .- 1463-9076. ; 25:32, s. 21215-21226
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Tidskriftsartikel (refereegranskat)abstract
- Disaccharides are well known to be efficient stabilizers of proteins, for example in the case of lyophilization or cryopreservation. However, although all disaccharides seem to exhibit bioprotective and stabilizing properties, it is clear that trehalose is generally superior compared to other disaccharides. The aim of this study was to understand this by comparing how the structural and dynamical properties of aqueous trehalose and sucrose solutions influence the protein myoglobin (Mb). The structural studies were based on neutron and X-ray diffraction in combination with empirical potential structure refinement (EPSR) modeling, whereas the dynamical studies were based on quasielastic neutron scattering (QENS) and molecular dynamics (MD) simulations. The results show that the overall differences in the structure and dynamics of the two systems are small, but nevertheless there are some important differences which may explain the superior stabilizing effects of trehalose. It was found that in both systems the protein is preferentially hydrated by water, but that this effect is more pronounced for trehalose, i.e. trehalose forms less hydrogen bonds to the protein surface than sucrose. Furthermore, the rotational motion around dihedrals between the two glucose rings of trehalose is slower than in the case of the dihedrals between the glucose and fructose rings of sucrose. This leads to a less perturbed protein structure in the case of trehalose. The observations indicate that an aqueous environment closest to the protein molecules is beneficial for an efficient bioprotective solution.
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| 2. |
- Ahlgren, Kajsa, 1996
(författare)
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Sweet stability
- 2024
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The disaccharide trehalose is known for its ability to stabilise proteins by preventing aggregation and elevating their denaturation temperature, consequently avoiding unfolding. The folding and function of proteins are vital for many biological processes. However, the underlying mechanisms of the stabilising effect of trehalose are not yet fully elucidated. A group of diseases known as amyloidosis is associated with the formation of amyloid fibrils, highly structured protein aggregates that can form in various tissues in the body. Enhancing our understanding of protein misfolding and the role of sugars in preventing amyloid fibril formation is therefore of great importance. In this thesis, the stabilising effect of trehalose is compared with that of sucrose, a structurally similar disaccharide. This comparison aims to solve unanswered questions regarding their interactions with proteins and surrounding water molecules. X-ray and neutron scattering confirmed that myoglobin is preferentially hydrated by water and revealed that trehalose slows down the dynamics of the protein to a greater extent than sucrose, with minimal direct interaction. Differential scanning calorimetry showed that both disaccharides increase the denaturation temperature of the protein lysozyme, sucrose slightly more than trehalose. Additionally, the glass transition temperature of trehalose is marginally higher. Small and wide-angle x-ray scattering demonstrated that both sugars inhibit amyloid fibril formation. The findings suggest that the effectiveness of both disaccharides in stabilising proteins varies with temperature; trehalose is more effective at lower temperatures around the glass transition, whereas sucrose may be slightly more efficient at higher temperatures around protein denaturation.
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| 3. |
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| 4. |
- Ahlgren Ode, Kajsa, et al.
(författare)
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A business model pattern arrives … and then? A translation perspective on business model innovation in established firms
- 2024
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Ingår i: Strategic Organization. - : SAGE Publications. - 1476-1270 .- 1741-315X.
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Tidskriftsartikel (refereegranskat)abstract
- This study examines business model innovation in an established firm. We investigate the case of a Swedish utility company that adopted and implemented a business model pattern originating from outside the firm. We draw upon Scandinavian translation theory to understand the micro-level dynamics of how business model innovation unfolds. Our findings show that the business model pattern is disassembled into its constituent parts, that these are translated separately and, little by little, (re)assembled into a whole to form a new business model. This process involves several loops of translation activated by the interplay between five practices: formulating, engaging, resisting, anchoring, and energizing. On the basis of our findings, we develop a business model translation framework. We thereby contribute to a better understanding of the micro-level perspective on business model innovation initiated by the adoption of a business model pattern. We also reveal that business model innovation processes triggered by business model patterns from outside differ from those taking place when a new business model is entirely developed within a firm.
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| 5. |
- Ahlgren, Serina, et al.
(författare)
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Description of the Agrosfär model – a tool for the climate impact assessment of farms, crop and animal production systems in Sweden
- 2024
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The agricultural sector in Sweden needs to cut GHG emissions and contribute to the climate goal of net-zero emissions by 2045. The GHG reduction goal for agricultural emissions is not quantified, but the Swedish climate policy framework states that ‘Swedish food production shall increase as much as possible with as little climate impact as possible’. Multiple key actors within the sector of food and agriculture have developed roadmaps or industry specific goals for reducing GHG emissions from the sector. Consequently, requirements for transparent GHG accounting and reporting are increasing within the agricultural sector, both on a national and international level. The purpose of the Agrosfär tool is to establish an automatic data driven climate calculator used to calculate GHG emissions from agricultural products and on a farm enterprise level. Automation and automatic data collection will save time, increase the accuracy of the calculations, and simplify updates of the tool to keep it aligned with the most recent climate data and climate reporting methodology. It will make it possible to continuously carry out follow-ups on climate performance indicators and measure improvements from climate measures taken. A working group consisting of agricultural life cycle assessment experts has developed the framework of the tool (e.g., setting system boundaries, selecting methodologies and input data). A technical team has developed algorithms, a digital interface and coupled the tool to other existing agricultural databases, providing farm specific information on crop and animal production data, soil characteristics, carbon footprints and amounts of purchased inputs etc. The tool and user interface have been developed based on input from farmers through prototyping and in-depth interviews. The priority guidelines on which the calculation model is based are the Product Environmental Footprint Category Rules (PEFCR), the International Dairy Federation (IDF)’s approach for carbon footprint for the dairy sector, and FAO Livestock Environmental Assessment and Performance guidelines (FAO LEAP). From the farm perspective, the Greenhouse Gas Protocol (GHG Protocol) Corporate Standard, GHG Protocol Agricultural Guidance (Scope 1 & 2) and GHG Protocol Corporate value chain (Scope 3) Accounting and Reporting Standard are guiding standards. Where standards have diverged or where assumptions have been required, the working group has made expert judgements on which method/guideline to follow or what assumptions to make. A first version of the tool, first described in report version 1, was developed as the basis for further development. The first version contains an animal and a crop module, and can calculate the carbon footprint of crops, milk and beef. This report (version 1.1) has been updated to include the most recent developments of the tool. The main change is that the tool can now also be used to calculate farm climate impact on a yearly basis. Future possibilities to develop the tool and calculation model are described in chapter 7, including suggestions for developing modules for more animal production types, deepening the integration between the crop and animal modules, expanding sources for automatic data collection, developing a carbon sequestration module, and other technical and methodological improvements to ensure alignment with important climate reporting standards. The report will be repeatedly updated as the tool develops, and new versions of the tool are released.
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| 6. |
- Jonsson, Olivia, 2001, et al.
(författare)
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Comparison of Sucrose and Trehalose for Protein Stabilization Using Differential Scanning Calorimetry
- 2024
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Ingår i: Journal of Physical Chemistry B. - 1520-5207 .- 1520-6106. ; 128:20, s. 4922-4930
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Tidskriftsartikel (refereegranskat)abstract
- The disaccharide trehalose is generally acknowledged as a superior stabilizer of proteins and other biomolecules in aqueous environments. Despite many theories aiming to explain this, the stabilization mechanism is still far from being fully understood. This study compares the stabilizing properties of trehalose with those of the structurally similar disaccharide sucrose. The stability has been evaluated for the two proteins, lysozyme and myoglobin, at both low and high temperatures by determining the glass transition temperature, Tg, and the denaturation temperature, Tden. The results show that the sucrose-containing samples exhibit higher Tden than the corresponding trehalose-containing samples, particularly at low water contents. The better stabilizing effect of sucrose at high temperatures may be explained by the fact that sucrose, to a greater extent, binds directly to the protein surface compared to trehalose. Both sugars show Tden elevation with an increasing sugar-to-protein ratio, which allows for a more complete sugar shell around the protein molecules. Finally, no synergistic effects were found by combining trehalose and sucrose. Conclusively, the exact mechanism of protein stabilization may vary with the temperature, as influenced by temperature-dependent interactions between the protein, sugar, and water. This variability can make trehalose to a superior stabilizer under some conditions and sucrose under others.
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| 7. |
- Stepulane, Annija, 1994, et al.
(författare)
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Lyotropic liquid crystal elastomers for drug delivery
- 2023
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Ingår i: Colloids and Surfaces B: Biointerfaces. - 0927-7765 .- 1873-4367. ; 226
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Tidskriftsartikel (refereegranskat)abstract
- Silicone elastomers like polydimethylsiloxane (PDMS) possess a combination of attractive material and biological properties motivating their widespread use in biomedical applications. Development of elastomers with capacity to deliver active therapeutic substances in the form of drugs is of particular interest to produce medical devices with added functionality. In this work, silicone-based lyotropic liquid crystal elastomers with drug-eluting functionality were developed using PDMS and triblock copolymer (diacrylated Pluronic F127, DA-F127). Various ternary PDMS–DA-F127–H2O compositions were explored and evaluated. Three compositions were found to have specific properties of interest and were further investigated for their nanostructure, mechanical properties, water retention capacity, and morphology. The ability of the elastomers to encapsulate and release polar and nonpolar substances was demonstrated using vancomycin and ibuprofen as model drugs. It was shown that the materials could deliver both types of drugs with a sustained release profile for up to 6 and 5 days for vancomycin and ibuprofen, respectively. This works demonstrates a lyotropic liquid crystal, silicone-based elastomer with tailorable mechanical properties, water retention capacity and ability to host and release polar and nonpolar active substances.
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