| 1. |
- Anthony, Niklas
(author)
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Laser Interaction with Minerals Common on Asteroids
- 2021
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Doctoral thesis (other academic/artistic)abstract
- Asteroids are worth studying for three reasons: planetary protection, industrial applications, and scientific knowledge. It is critical we develop technologies capable of diverting objects on collision courses with our planet. We can use the same technology to move or process asteroids and comets for materials to build structures or refuel in Low-Earth Orbit. Asteroids are also windows into the past; they were formed in the early Solar System, and could potentially have been the source of water and/or life on Earth. There are unique challenges to manipulating an asteroid or asteroid materials, which means that much of what we know about material processing needs to be revamped to fit the situation. One of the motivating drives of this research was that a laser would be an excellent tool to perform many tasks at an asteroid.One process of interest is laser drilling. The surface composition of asteroids is altered by aeons of space weathering; by studying the subsurface composition we can ascertain just how much it is altered and possibly by which processes. It is possible that hydrated minerals or ices exist below the surface as well, which are of great economic interest in asteroid mining. One of the greatest challenges to get under the surface of an asteroid is the low gravity: any forces or torques generated by a sampling mechanism may tip the spacecraft or launch it into deep space. A laser does not generate any significant forces, and can even be used without having to land; lasers do use a lot of electric power so the laser parameters need to be optimized to minimize the size and power requirements of the spacecraft. We found that nearly 1-cm deep holes can be made with as little as 18~J of energy using a 300-W laser.Laser ablation has been studied as a mechanism to redirect asteroids, but it is not particularly energy efficient at material removal. If the idea is to create a momentum exchange by removing surface material beyond an object's gravitational pull, then there could perhaps be more energy efficient mechanisms. One mechanism we investigated was spallation, where the shock wave of a laser pulse breaks off a relatively large chunk of material without having to melt and vaporize it. We found that spallation may be many times more energy efficient than ablation.Laser welding of metals has been of industrial interest for decades, though the welding of two different materials is still a challenge. We sought to develop a laser-based wire-attachment mechanism that can be used to anchor spacecraft to the surface of a small body or to maneuver boulders or small asteroids. When attempting to follow a traditional welding process, it was found that the two melt pools would not mix, and if it did, it was very weak. Instead, we used the laser to drill a hole and melt a wire while inserting it into the hole. This produced a solid anchor with a hold strength of up to 120~N.
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| 2. |
- Bergstrand, Sofie, et al.
(author)
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Biallelic mutations in WRAP53 result in dysfunctional telomeres, Cajal bodies and DNA repair, thereby causing Hoyeraal-Hreidarsson syndrome
- 2020
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In: Cell Death and Disease. - : Nature Publishing Group. - 2041-4889. ; 11:4
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Journal article (peer-reviewed)abstract
- Approximately half of all cases of Hoyeraal-Hreidarsson syndrome (HHS), a multisystem disorder characterized by bone marrow failure, developmental defects and very short telomeres, are caused by germline mutations in genes related to telomere biology. However, the varying symptoms and severity of the disease indicate that additional mechanisms are involved. Here, a 3-year-old boy with HHS was found to carry biallelic germline mutations in WRAP53 (WD40 encoding RNA antisense to p53), that altered two highly conserved amino acids (L283F and R398W) in the WD40 scaffold domain of the protein encoded. WRAP53 beta (also known as TCAB1 or WDR79) is involved in intracellular trafficking of telomerase, Cajal body functions and DNA repair. We found that both mutations cause destabilization, mislocalization and faulty interactions of WRAP53 beta, defects linked to misfolding by the TRiC chaperonin complex. Consequently, WRAP53 beta HHS mutants cannot elongate telomeres, maintain Cajal bodies or repair DNA double-strand breaks. These findings provide a molecular explanation for the pathogenesis underlying WRAP53 beta-associated HHS and highlight the potential contribution of DNA damage and/or defects in Cajal bodies to the early onset and/or severity of this disease.
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| 3. |
- Blazic, Marija, et al.
(author)
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High-throughput selection of (new) enzymes : phage display-mediated isolation of alkyl halide hydrolases from a library of active-site mutated epoxide hydrolases
- 2024
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In: Faraday discussions. - : Royal Society of Chemistry. - 1359-6640 .- 1364-5498.
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Journal article (peer-reviewed)abstract
- Epoxide hydrolase StEH1, from potato, is similar in overall structural fold and catalytic mechanism to haloalkane dehalogenase DhlA from Xanthobacter autotrophicus. StEH1 displays low (promiscuous) hydrolytic activity with (2-chloro)- and (2-bromo)ethanebenzene producing 2-phenylethanol. To investigate possibilities to amplify these very low dehalogenase activities, StEH1 was subjected to targeted randomized mutagenesis at five active-site amino acid residues and the resulting protein library was challenged for reactivity towards a bait chloride substrate. Enzymes catalyzing the first half-reaction of a hydrolytic cycle were isolated following monovalent phage display of the mutated proteins. Several StEH1 derived enzymes were identified with enhanced dehalogenase activities.
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| 4. |
- Cornelius Chukwu, Eugenia, et al.
(author)
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Engineered Aldolases Catalyzing Stereoselective Aldol Reactions Between Aryl-Substituted Ketones and Aldehydes
- 2023
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In: Catalysis Science & Technology. - : Royal Society of Chemistry. - 2044-4753 .- 2044-4761.
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Journal article (peer-reviewed)abstract
- An A129G/R134V/S166G triple mutant of fructose 6-phosphate aldolase (FSA) from Escherichia coli was further engineered with the goal to generate new enzyme variants capable of catalyzing aldol reactions between aryl substituted ketones and aldehydes. Residues L107 and L163 were subjected to saturation mutagenesis and the resulting library of FSA variants was screened for catalytic activity with 2-hydroxyacetophenone and phenylacetaldehyde as substrates. A selection of aldolase variants was identified that catalyze the synthesis of 2,3-dihydroxy-1,4-diphenylbutanone. The most active enzyme variants contained an L163C substitution. An L107C/L163C variant was further tested for activity with substituted phenylacetaldehydes, and was shown to afford the production of the corresponding diphenyl substituted butanones with good diastereoselectivities (anti : syn dr of 10 to 30) and reasonable to good enantioselectivities of syn enantiomers (er of 5 to 25).
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| 5. |
- Norberg, Anna-Maija, 1957-
(author)
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Skriftpraktiker i idrott och hälsa på högstadiet : en textetnografisk undersökning
- 2021
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Doctoral thesis (other academic/artistic)abstract
- In Physical Education and Health (PEH), a previously almost entirely practical subject, the use of written texts has increased considerably, which can be assumed to have consequences on the subject and on students’ meaning making. The purpose of this thesis is to investigate the functions of written texts in PEH. Three research questions are answered: 1. How, when, and why are texts used in instructional practices in PEH?; 2. What text themes are most dominant in the used texts, and what specific subject content is entextualized?; and 3. What disciplinary identities do PEH-texts offer the students?The main theoretical framework is New Literacy Studies (NLS), and an ecological approach to literacy as social practice is employed. Text ethnographic methods are used for data collection and analysis along with concepts from discourse and genre studies. Texts and ethnographic data are collected during a three-semester-long field study of a PEH-teacher and a class in a lower secondary school. In addition, interviews with five PEH-teachers are performed.Article 1 shows that texts are used for a wide array of purposes, and as tools for theoretical as well as physical learning activities. Movement is shown to be the most frequently entextualized subject content. Written assessment comments, investigated in Article 2, most often acknowledge subject specific knowledge in students’ written assignments. In Article 3, the most prominent genres identified address measuring and training of the body. The students are mainly positioned physiologically, but also in relation to ideas from the humanities and social sciences. In Article 4, the use of texts is legitimated as practical, timesaving and a well-known tool for instruction and assessment. However, writing and text practices steal time from embodied learning and may not suit all students.In summary, the thesis shows that it is possible to use texts and still maintain the focus on embodied learning. If they are used functionally and strategically, texts can contribute to and develop instruction in PEH, rather than threaten the subject.
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| 6. |
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| 7. |
- Norberg, Magnus, 1972-
(author)
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On Institutional Demands in Banking and the Exchange of Hard and Soft Accounting Information
- 2022
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Doctoral thesis (other academic/artistic)abstract
- The overarching purpose of the thesis is to explore how institutional demands influence banks, which has been a core issue in banking research. This has become even more critical since the financial crisis of 2007–2009. By conducting a qualitative study and paying attention to the exchange of different forms of hard and soft accounting information, the thesis expands the current knowledge on how institutional demands influence highly regulated organisations, such as banks, which can face sanctions if they are not compliant when potential regulations enter into force.The thesis contributes to literature on institutional demands, as the thesis shows that even financial regulatory initiatives influence banks. Accordingly, the potential regulations can create tensions between banks and regulators. Here, the increased dependency on information technology (IT), which must be developed, is central. This is demonstrated by studying regulations and the formation of regulatory initiatives, including MiFID II, KRITA and financial robo-advising.The thesis includes four individual studies and puts them in a larger context, and it relates them to each other to increase our knowledge. Study I, which contributes to knowledge on how exchanges between firms and banks take place. It demonstrates that the exchange is more complex than previous literature suggests, and that the exchange differs depending on what financial services are considered. Studies II–IV then add knowledge on how institutional demands, manifested by regulations and regulatory initiatives, influence banks. These studies also reflect on the importance of qualitative information when adopting new financial regulations and when regulating certain bank services, primarily those services that rely on softer forms of accounting information.Specifically, Study IV demonstrates how financial robo-advising comes into being and influences financial intermediaries, including FinTech companies, such as modern banks, by focusing on the regulatory discourse and the regulators’ definition of financial robo-advising.Furthermore, the thesis contributes to the literature on hard and soft accounting information, in the sense that there are a number of different definitions that, to some extent, can be paradoxical. The study demonstrates how the definition that is used in our attempt to capture accounting information also influences the result. This touches on the value that we attempt to measure and the core of what is considered as accounting information.Finally, the thesis demonstrates that regulators tend to rely more on information, such as numbers and quantitative information, instead of more context dependent information, such as qualitative information. Thus, the demanded accounting information influences and materialises, to some extent, what banks become. This means that the demand from regulators influences these regulated firms, which, in turn, adapt to the demands and develop their infrastructure accordingly. Thus, the IT-infrastructure becomes a part of our physical reality – i.e. the ideas and demands of regulators become transformed by the regulated into the physical information systems, manifested by e.g. financial robo-advisors.
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| 8. |
- Olsson, Martin, et al.
(author)
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Educational intervention in triage with the Swedish triage scale RETTS©, with focus on specialist nurse students in ambulance and emergency care – A cross-sectional study
- 2022
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In: International Emergency Nursing. - : Elsevier. - 1755-599X .- 1878-013X. ; 63
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Journal article (peer-reviewed)abstract
- AimTo determine the reliability of application of the RETTS© triage scale after an educational intervention using paper-based scenarios in emergency care education.BackgroundKnowledge about and education in triage are important factors in triagescale implementation. Presenting students with a large number of triage scenarios is a common part of triage education.MethodsIn this prospective cross-sectional study at two universities students undergoing education in emergency care used RETTS© to assess triage level in 46 paper-based scenarios.Results57 students in the study made 2590 final triage decisions. Fleiss Kappa for final triage was 0.411 which is in the lower range of moderate agreement. In 25 of 46 (53.4%) scenarios, final triage levels did not agree about whether the case was stable or unstable.Conclusion/ImplicationsApplication of the RETTS© triage scale after an educational intervention with paper-based simulation in emergency care education resulted in moderate agreement about the final levels of triage.
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