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- Aulin, Christian, 1980-
(author)
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Novel oil resistant cellulosic materials
- 2009
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Doctoral thesis (other academic/artistic)abstract
- The aim of this study has been to prepare and characterise oil resistant cellulosic materials, ranging from model surfaces to papers and aerogels. The cellulosic materials were made oil resistant by chemical and topographic modifications, based on surface energy, surface roughness and barrier approaches. Detailed wetting studies of the prepared cellulosic materials were made using contact angle measurements and standardised penetration tests with different alkanes and oil mixtures. A significant part of the activities were devoted to the development of model cellulosic surfaces with different degrees of crystalline ordering for the wetting studies. Crystalline cellulose I, II and amorphous cellulose surfaces were prepared by spin-coating of cellulose nanocrystal or microfibrillated cellulose (MFC) dispersions, with Langmuir-Schaefer (LS) films or by a layer-by-layer (LbL) deposition technique. The formation of multilayers consisting of polyethyleneimine (PEI)/anionic MFC or cationic MFC/anionic MFC was further studied and optimized in terms of total layer thickness and adsorbed amount by combining Dual Polarization Interferometry (DPI) or Stagnation Point Adsorption Reflectrometry (SPAR) with a Quartz Crystal Microbalance with Dissipation (QCM-D). The smooth cellulosic surfaces prepared had different molecular and mesostructure properties and different surface energies as shown by X-ray diffraction, Atomic Force Microscopy (AFM) imaging, ellipsometry measurements and contact angle measurements. The cellulose model surfaces were found to be ideal for detailed wetting studies, and after the surface has been coated or covalently modified with various amounts of fluorosurfactants, the fluorinated cellulose films were used to follow the spreading mechanisms of different oil mixtures. The viscosity and surface tension of the oil mixtures, as well as the dispersive surface energy of the cellulose surfaces, were found to be essential parameters governing the spreading kinetics. A strong correlation was found between the surface concentration of fluorine, the dispersive surface energy and the measured contact angle of the oil mixtures. Silicon surfaces possessing structural porous characteristics were fabricated by a plasma etching process. The structured silicon surfaces were coated with sulfate-stabilized cellulose I nanocrystals using the LbL technique. These artificial intrinsically oleophilic cellulose surfaces were made highly oleophobic when coated with a thin layer of fluorinated silanes. By comparison with flat cellulose surfaces, which are oleophilic, it is demonstrated that the surface energy and the surface texture are essential factors preventing oil from spreading on the surface and, thus, inducing the observed macroscopic oleophobic properties. The use of the MFC for surface coating on base papers demonstrated very promising characteristics as packaging materials. Environmental-Scanning Electron Microscopy (E-SEM) micrographs indicated that the MFC layer reduced the sheet porosity, i.e. the dense structure formed by the nanofibers resulted in superior oil barrier properties. Attempts were made to link the procedure for preparation of the MFC dispersions to the resulting microstructure of the coatings, and film porosity and the film moisture content to the resulting permeability properties. Finally, MFC aerogels were successfully prepared by freeze-drying. The surface texture of the porous aerogels was carefully controlled by adjusting the concentration of the MFC dispersion used for the freeze-drying. The different scales of roughness of the MFC aerogels were utilised, together with the very low surface energy created by fluorination of the aerogel, to induce highly oleophobic properties.
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- Bass, Gary Alan, 1979-, et al.
(author)
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Cardiac risk stratification in emergency resection for colonic tumours
- 2021
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In: BJS Open. - : John Wiley & Sons. - 2474-9842. ; 5:4
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Journal article (peer-reviewed)abstract
- BACKGROUND: Despite advances in perioperative care, the postoperative mortality rate after emergency oncological colonic resection remains high. Risk stratification may allow targeted perioperative optimization and cardiac risk stratification. This study aimed to test the hypothesis that the Revised Cardiac Risk Index (RCRI), a user-friendly tool, could identify patients who would benefit most from perioperative cardiac risk mitigation.METHODS: Patients who underwent emergency resection for colonic cancer from 2007 to 2017 and registered in the Swedish Colorectal Cancer Registry (SCRCR) were analysed retrospectively. These patients were cross-referenced by social security number to the Swedish National Board of Health and Welfare data set, a government registry of mortality, and co-morbidity data. RCRI scores were calculated for each patient and correlated with 90-day postoperative mortality risk, using Poisson regression with robust error of variance.RESULTS: Some 5703 patients met the study inclusion criteria. A linear increase in crude 90-day postoperative mortality was detected with increasing RCRI score (37.3 versus 11.3 per cent for RCRI 4 or more versus RCRI 1; P < 0.001). The adjusted 90-day all-cause mortality risk was also significantly increased (RCRI 4 or more versus RCRI 1: adjusted incidence rate ratio 2.07, 95 per cent c.i. 1.49 to 2.89; P < 0.001).CONCLUSION: This study documented an association between increasing cardiac risk and 90-day postoperative mortality. Those undergoing emergency colorectal surgery for cancer with a raised RCRI score should be considered high-risk patients who would most likely benefit from enhanced postoperative monitoring and critical care expertise.
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- Benvenuti, Luca, et al.
(author)
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Automotive Control
- 2009. - 1
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In: Handbook of Hybrid Systems and Control, Theory – Tools – Applications. - 9780521765053 ; , s. 439-470
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Book chapter (peer-reviewed)abstract
- utomotive systems offer a rich opportunity for hybrid models, controls, and tools. Beyond the traditional use of hybrid models for representing the behavior of the composition of discrete controller and continuous plants, automotive mechanical systems exhibit hybrid behavior as demonstrated in this chapter. In addition, hybrid systems can be used to capture system specifications at the highest level of abstraction and to model implementation architectures thus enabling a rich design space exploration.
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- Böhler, Tom, 1955
(author)
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Wind power, landscape and meaning : Some reflections about contemporary use of land from a human ecological perspective
- 2004
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In: Land - Natur - Konsum. Bilder und Konzeptionen im humanökologischen Diskurs. Wolfgang Serbser, Fritz Reusswig, Heide Inhetveen (eds.). Edition Humanökologie, Band 3. - München : oekom verlag. - 3936581800 ; , s. 119-128
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Book chapter (other academic/artistic)abstract
- [The book, in German:] Unterschiedliche Sichtweisen von Situationen und Vorstellungen, wie etwas sein könnte und wie es sein sollte, prägen nicht nur unser Alltagshandeln. Sie sind auch Bestandteil unserer wissenschaftlichen Modelle und der daraus abgeleiteten Handlungskonzepte. Gerade weil sie sich häufig dem wissenschaftlichen Diskurs entziehen und nicht bewusst in wissenschaftliche Theorien einfließen, werden sie in diesem dritten Band der Edition Humanökologie auf die Agenda gesetzt. Wissenschaftler und Wissenschaftlerinnen der Humanökologie, der Umweltsoziologie und Agrarsoziologie analysieren in ihren Beiträgen zu den Themenfeldern "Land" (als Landschaft und Landwirtschaft) "Natur" und "Konsum" diese sowohl wissenschaftlich als auch gesellschaftlich folgenreichen Vorstellungs- und Bildwelten.
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- Connallon, Tim, et al.
(author)
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Natural selection and the distribution of chromosomal inversion lengths
- 2021
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In: Molecular Ecology. - : Wiley. - 0962-1083 .- 1365-294X.
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Journal article (peer-reviewed)abstract
- Chromosomal inversions contribute substantially to genome evolution, yet the processes governing their evolutionary dynamics remain poorly understood. Theory suggests that a readily measurable property of inversions—their length—can potentially affect their evolutionary fates. Emerging data on the lengths of polymorphic and fixed inversions may therefore provide clues to the evolutionary processes promoting in- version establishment. However, formal predictions for the distribution of inversion lengths remain incomplete, making empirical patterns difficult to interpret. We model the relation between inversion length and establishment probability for four inversion types: (1) neutral, (2) underdominant, (3) directly beneficial, and (4) indirectly beneficial, with selection favouring the latter because they capture locally adapted alleles at migration-selection balance and suppress recombination between them. We also consider how deleterious mutations affect the lengths of established inversions. We show that length distributions of common polymorphic and fixed inversions systematically differ among inversion types. Small rearrangements contribute the most to genome evolution under neutral and underdominant scenarios of selection, with the lengths of neutral inversion substitutions increasing, and those of underdominant substitutions decreasing, with effective population size. Among directly beneficial inver- sions, small rearrangements are preferentially fixed, whereas intermediate-to-large inversions are maintained as balanced polymorphisms via associative overdominance. Finally, inversions established under the local adaptation scenario are predominantly intermediate-to-large. Such inversions remain polymorphic or approach fixation within the local populations where they are favoured. Our models clarify how inver- sion length distributions relate to processes of inversion establishment, providing a platform for testing how natural selection shapes the evolution of genome structure.
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8. |
- Dannestam, Tove
(author)
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Stadspolitik i Malmö : Politikens meningsskapande och materialitet
- 2009
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Doctoral thesis (other academic/artistic)abstract
- In international research there is a near consensus that the importance of cities is growing. As the policymakers of contemporary cities redirect their policy orientations away from the goal of redistribution towards achieving economic competitiveness, and as they introduce new structures of governance, they are becoming more and more committed to entrepreneurial city politics. However, both the international and Nordic research communities have shown little interest in studying whether these trends are viable in a Nordic context. Thus, through a case study of the city of Malmö, this doctoral dissertation explores the introduction of entrepreneurial city politics in a Swedish setting. Malmö is a former flagship for the Social Democratic ‘welfare city’ and a city that now is undergoing a process of politico-economic transformation. Theoretically, the author develops a framework for the analysis of policy-making in general and how cities turn towards urban entrepreneurialism in particular. ‘The Lancaster School of Cultural Political Economy’ is applied and redeveloped through interpretative policy analysis, urban regime theory and the politics of scale approach. Taken together, these traditions represent the basis for the conceptualization of politics within the dissertation. The author proposes an understanding of politics as practiced through an interplay of discursive and material processes and beyond the processes traditionally associated with a narrow ‘government-based’ conceptualization of politics. A framework is constructed to analyze how discourses, such as the discourse on the necessity of cities being entrepreneurial, are translated into political practice through three different moments. The moments of ‘selection’, ‘actors mobilizing discourse-coalitions’ and ‘institutionalization’ structure the empirical analysis of city politics in Malmö. The author demonstrates how key actors create, mediate and translate the discourse on urban entrepreneurialism to fit the actual (previously welfare oriented) context of local government. Powerful coalitions of various actors are mobilized around three different ‘micro-discourses’ that materialize into institutional, organizational and political practice. As a result of the analysis, the author reveals six different technologies of institutionalization which actors employ and which are essential for the practice of entrepreneurial city politics in Malmö. The overall aim of the dissertation is to contribute to the on-going re-conceptualization of politics in general and local politics in particular. Political scientists tend to treat local politics as equal to ‘sub-national municipal politics’, i.e. as politics defined in relation to the central state, mainly concerned with service delivery and occurring within the formal decision-making processes of local government. In contrast, the author argues that we need to rethink local politics and that such a task of re-conceptualization is especially urgent in a Nordic context, where the idea of ‘municipal politics’ has functioned as “an iron-grip on political imagination”. In the final section the theoretical framework developed within the dissertation is proposed as one way of rethinking local politics. The author also discusses why the presence of entrepreneurial city politics challenges the traditional organization and orientation of local politics in Sweden. Conclusions are drawn regarding our understanding of politics in general and some remarks on a future research agenda centered on the cultural political economy of contemporary city politics are given.
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