| 1. |
- Hellström, Mats, et al.
(författare)
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Towards the development of a bioengineered uterus : Comparison of different protocols for rat uterus decellularization
- 2014
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Ingår i: Acta Biomaterialia. - : Elsevier BV. - 1742-7061 .- 1878-7568. ; 10:12, s. 5034-5042
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Tidskriftsartikel (refereegranskat)abstract
- Uterus transplantation (UTx) may be the only possible curative treatment for absolute uterine factor infertility, which affects 1 in every 500 females of fertile age. We recently presented the 6-month results from the first clinical UTx trial, describing nine live-donor procedures. This routine involves complicated surgery and requires potentially harmful immune suppression to prevent rejection. However, tissue engineering applications using biomaterials and stem cells may replace the need for a live donor, and could prevent the required immunosuppressive treatment. To investigate the basic aspects of this, we developed a novel whole-uterus scaffold design for uterus tissue engineering experiments in the rat. Decellularization was achieved by perfusion of detergents and ionic solutions. The remaining matrix and its biochemical and mechanical properties were quantitatively compared from using three different protocols. The constructs were further compared with native uterus tissue composition. Perfusion with Triton X-100/dimethyl sulfoxide/H2O led to a compact, weaker scaffold that showed evidence of a compromised matrix organization. Sodium deoxycholate/dH2O perfusion gave rise to a porous scaffold that structurally and mechanically resembled native uterus better. An innovative combination of two proteomic analyses revealed higher fibronectin and versican content in these porous scaffolds, which may explain the improved scaffold organization. Together with other important protocol-dependent differences, our results can contribute to the development of improved decellularization protocols for assorted organs. Furthermore, our study shows the first available data on decellularized whole uterus, and creates new opportunities for numerous in vitro and in vivo whole-uterus tissue engineering applications.
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| 2. |
- Olsson, Sara, et al.
(författare)
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A SEM study on the use of epoxy functional vegetable oil and reactive UV-absorber as UV-protecting pretreatment for wood
- 2015
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Ingår i: Polymer degradation and stability. - : Elsevier BV. - 0141-3910 .- 1873-2321. ; 113:SI, s. 40-45
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Tidskriftsartikel (refereegranskat)abstract
- The present study investigates the ageing performance of a UV protective system for wood, comprising the reactive UV absorber 2-hydroxy-4(2,3-epoxypropoxy)-benzophenone (HEPBP) and epoxy functional vegetable oils (linseed and soybean oil). Scots pine samples of radial or cross-sectional surfaces were treated using a combination of the two components, or using only one of the oils. The treated samples were then aged in a Weather-Ometer for 2 x 60 h and analysed using VPSEM to follow the degradation of the wood substrate in the exact same spot before, during and after ageing. The results of the radial surfaces show slightly less degradation of samples treated with a combination of HEPBP and oil, and for the cross-sectional surfaces an even stronger protective effect is visible. For samples treated with only one of the two oils, no improvement was detectable. The radial surfaces were also analysed using FTIR where the results indicate presence of the protective treatment even after 120 h of exposure. Overall the combined pretreatment of HEPBP and epoxy functional linseed oil was concluded to have a photo-stabilising effect of the wood substrate.
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| 3. |
- Olsson, Sara, et al.
(författare)
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Covalently attached UV-absorbers for improved UV-protection of wood
- 2010
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Ingår i: Proceedings of The Fifth European Conference on Wood Modification ECWM5. - : Latvian State Institute of Wood Chemistry.
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Konferensbidrag (refereegranskat)abstract
- The present study describes the use of reactive UV-absorbers (UVAs) that can be covalently attached to a wood substrate to obtain an improved exterior durability. It has previously been demonstrated that the photostability of wood is increased if the UVA is grafted to the wood surface. The grafting of an epoxide-functional UVA, 2-hydroxy-4(2,3-epoxypropoxy)-benzophenone (HEPBP), to thin veneer wood specimens had a larger photostabilizing effect than if the corresponding UVA without the reactive handle was added to the wood coating. The present study shows that not only the chemical structure of the UVA is important but also how the modification is performed i.e. the reaction procedure. A successful attachment of the UVA depends on both the reaction conditions as well as if other reactive species are present at the same time. The presence of for example a vegetable oil (epoxy functionalized soy bean oil) affects the grafting reaction of the UVA. Details on the effect of reaction conditions, reaction sequences, and presence of co-reactants will be presented.
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| 4. |
- Olsson, Sara, 1984-
(författare)
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Enhancing UV-protection of clear coated wood by utilizing reactive UV-absorber and epoxyfunctionalized soybean oil
- 2012
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This work presents the development of a new pretreatment for clear coated wood, that aims to increase the photoprotection of exterior wood products, and at the same time make the system more environmentally friendly. The pretreatment comprises the reactive UV absorber 2-hydroxy-4(2,3-epoxypropoxy)-benzophenone (HEPBP), which has a primary epoxy group that can be covalently attached to the hydroxyl groups of the wood substrate. This reactant is accompanied by renewable epoxy functionalized soybean oil (ESBO), which contains a secondary epoxy group that also has the ability to react with the substrate and that promotes the compatibility between the two reactants. The ESBO further seems to have the advantage of increasing the flexibility of the pretreated veneers as well as decreasing the amount of water in the cell wall of the wood. The study was performed in two parts where the first part focused solely on the development and performance of the pretreatment, whereas the second part used the knowledge gained from part one to evaluate the pretreatment in combination with an acrylic clear coating. Grafting reactions were performed on thin wood veneers heated in solvent. In the first part the reaction parameters, temperature and reaction time, were varied to study their effects on the final properties of the pretreatments. The veneers where then analyzed using FTIR to determine if grafting was achieved. Results show that grafting was successful for reactions performed at temperatures above 90 °C. For part two, grafting was successful for both the boil- and dip process, indicating that a considerably shorter reaction time can be used. Samples from both part one and two where then exposed to accelerated ageing and the color change was measured to estimate the UV-resistance. The first part showed improved UV-resistance for some of the pretreatments, whereas the second part was more difficult to evaluate due to the top coat, but a slight improvement can be seen for samples using the pretreatment. A positive result for part two is also that the pretreatment do not appear to affect the adhesion between the substrate and the top coat. It is hence concluded that the proposed pretreatment is a possible way of increasing the photostability of exterior wood.
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| 5. |
- Olsson, Sara, et al.
(författare)
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Grafting of 2-hydroxy-4(2,3-epoxypropoxy)-benzophenone and epoxidized soybean oil to wood : Reaction conditions and effects on the color stability of Scots pine
- 2012
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Ingår i: Polymer degradation and stability. - : Elsevier BV. - 0141-3910 .- 1873-2321. ; 97:9, s. 1779-1786
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Tidskriftsartikel (refereegranskat)abstract
- This study investigates the photostabilizing effect of the reactive UV-absorber 2-hydroxy-4(2,3-epoxypropoxy)-benzophenone (HEPBP) when used as a primer for wood. The present work further includes a study on the effect of HEPBP used in combination with an epoxy functionalized vegetable oil as a primer system. The study is based on reactions performed on pine veneers using 3-pentanone as a solvent and 4-(dimethylamino)pyridine (DMAP) as a catalyst, varying the reaction time and temperature. Results from FTIR and SEC measurements indicate that a desired reaction between HEPBP and wood does occur and that there are synergetic effects when HEPBP and oil are combined. Color measurements also indicate that the use of HEPBP and epoxidized soybean oil as pretreatment for wood results in a lower color change after 400 h of artificial weathering. We conclude that using HEPBP in combination with epoxy functionalized soybean oil does improve photostability of wood exposed to artificial weathering.
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| 6. |
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| 7. |
- Olsson, Sara, et al.
(författare)
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Reactive UV-absorber and epoxy functionalized soybean oil for enhanced UV-protection of clear coated wood
- 2014
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Ingår i: Polymer degradation and stability. - : Elsevier BV. - 0141-3910 .- 1873-2321. ; 110, s. 405-414
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Tidskriftsartikel (refereegranskat)abstract
- The present work investigates the photostabilising effect of a pretreatment consisting of 2-hydroxy-4(2,3-epoxypropoxy)-benzophenone (HEPBP) and epoxy functionalized soybean oil (ESBO), reacted on to Scots pine veneers coated with two different acrylic top coats. Two different pretreatment procedures were used, varying in reaction time and temperature. Results from FTIR and SEC analysis indicate that a large amount of reactant was present on the veneers after treatment with either of the two reaction procedures. Furthermore, coating of the pretreated surfaces was possible and the pretreatment does not seem to affect the adhesion between the coating and the wood substrate. Both accelerated ageing and natural exposure was used to study the resistance to photodegradation, and the results were analysed using colour measurements, FTIR and SEM. These analyses all show that 1400 h of accelerated ageing degrades neither the wood nor the coating to any larger extent. However, after 4000 h of UV exposure some signs of degradation are visible but to a lesser extent for pretreated samples. For the samples exposed to natural weathering during 14 months the performance was good in terms of photostabilisation, however all samples suffer from mould to different extents. Pretreated samples show smaller and more evenly distributed areas of mould compared to the references, which show slightly more mould. The combined coating/pretreatment system is thus assumed to have an effect in terms of photostabilization of the coated wood.
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| 8. |
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| 9. |
- Andersson, Helene, 1983, et al.
(författare)
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The influence of the molecular weight of the water-soluble polymer on phase-separated films for controlled release
- 2016
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Ingår i: International Journal of Pharmaceutics. - : Elsevier BV. - 0378-5173 .- 1873-3476. ; 511:1, s. 223-235
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Tidskriftsartikel (refereegranskat)abstract
- Hydroxypropyl cellulose (HPC) and ethyl cellulose (EC) can be used for extended release coatings, where the water-soluble HPC may act as a pore former. The aim was to investigate the effect of the molecular weight of HPC on the microstructure and mass transport in phase-separated freestanding EC/HPC films with 30% w/w HPC. Four different HPC grades were used, with weight averaged molecular weights (Mw) of 30.0 (SSL), 55.0 (SL), 83.5 (L) and 365 (M) kg/mol. Results showed that the phase-separated structure changed from HPC-discontinuous to bicontinuous with increasing Mw of HPC. The film with the lowest Mw HPC (SSL) had unconnected oval-shaped HPC-rich domains, leaked almost no HPC and had the lowest water permeability. The remaining higher Mw films had connected complex-shaped pores, which resulted in higher permeabilities. The highest Mw film (M) had the smallest pores and very slow HPC leakage, which led to a slow increase in permeability. Films with grade L and SL released most of their HPC, yet the permeability of the L film was three times higher due to greater pore connectivity. It was concluded that the phase-separated microstructure, the level of pore percolation and the leakage rate of HPC will be affected by the choice of HPC Mw grade used in the film and this will in turn have strong impact on the film permeability.
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| 10. |
- Andersson, Tim, et al.
(författare)
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Comparison of Machine Learning’s- and Humans’- Ability to Consistently Classify Anomalies in Cylinder Locks
- 2022
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Ingår i: IFIP Advances in Information and Communication Technology. - Cham : Springer Science and Business Media Deutschland GmbH. - 9783031164064 ; , s. 27-34, s. 27-34
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Konferensbidrag (refereegranskat)abstract
- Historically, cylinder locks’ quality has been tested manually by human operators after full assembly. The frequency and the characteristics of the testing procedure for these locks wear the operators’ wrists and lead to varying results of the quality control. The consistency in the quality control is an important factor for the expected lifetime of the locks which is why the industry seeks an automated solution. This study evaluates how consistently the operators can classify a collection of locks, using their tactile sense, compared to a more objective approach, using torque measurements and Machine Learning (ML). These locks were deliberately chosen because they are prone to get inconsistent classifications, which means that there is no ground truth of how to classify them. The ML algorithms were therefore evaluated with two different labeling approaches, one based on the results from the operators, using their tactile sense to classify into ‘working’ or ‘faulty’ locks, and a second approach by letting an unsupervised learner create two clusters of the data which were then labeled by an expert using visual inspection of the torque diagrams. The results show that an ML-solution, trained with the second approach, can classify mechanical anomalies, based on torque data, more consistently compared to operators, using their tactile sense. These findings are a crucial milestone for the further development of a fully automated test procedure that has the potential to increase the reliability of the quality control and remove an injury-prone task from the operators.
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