| 51. |
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| 52. |
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| 53. |
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| 54. |
- Svensson, Olof, et al.
(författare)
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Adsorption of delmopinol at the solid/liquid interface - the role of the acid-base equilibrium
- 2010
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Ingår i: Journal of Colloid and Interface Science. - : Elsevier Inc.. - 0021-9797 .- 1095-7103. ; 350:1, s. 275-281
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Tidskriftsartikel (refereegranskat)abstract
- Delmopinol is a tertiary amine surfactant that is used to counteract dental plaque formation. As it is of interest to understand the interfacial behavior from both fundamental and applied perspectives the adsorption of delmopinol to model surfaces was investigated. Adsorption on Teflon, titanium and stainless steel was studied by radioactive labeling and adsorption on silica was studied by quartz crystal microbalance (QCM), ellipsometry and particle electrophoresis. It was shown that the adsorption of delmopinol was complex and strongly influenced by pH and concentration. Pronounced peak values were detected in the adsorption curves (adsorbed amount versus concentration) exceeding the expected value for a bilayer type of structure. To account for this behavior two surface active component were assumed to be present. Accordingly, the high amounts result from the deposition of the component with lower solubility and the decrease at the critical micelle concentration can be explained by solubilization of this component. Based on data from several experimental methods and the pH dependence of the effect we propose an explanation in which the protonated and non-protonated forms of delmopinol represent the two components. However, it cannot be excluded that the component with the lower solubility could be a compound chemically different from delmopinol in the sample.
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| 55. |
- Svensson, Olof, et al.
(författare)
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Adsorption of serum albumin on silica : The influence of surface cleaning procedures
- 2010
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Ingår i: Journal of Colloid and Interface Science. - : Elsevier Inc.. - 0021-9797 .- 1095-7103. ; 344:1, s. 44-47
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Tidskriftsartikel (refereegranskat)abstract
- The objective of the investigation was to study how different surface cleaning procedures affect the subsequent adsorption of bovine serum albumin (BSA) on silica. Ellipsometry was used to monitor the adsorbed amount and thickness of the protein films in situ at physiological buffer conditions. Plasma treatment was found to effectively reduce the amount of BSA on silica and on surfaces cleaned with hydrogen peroxide solutions (RCA method) adsorption was essentially absent. On clean silica surfaces the ellipsometric data furthermore suggest that a depletion zone is present at the surface where the BSA concentration is lower than in the bulk solution. Additional experiments showed that calcium did not promote the adsorption of BSA and that the adsorption of human serum albumin (HSA) is essentially absent on clean silica surfaces in agreement with the results obtained for BSA. The presented work contributes to the general understanding of protein adsorption as well as provides information on how to control serum albumin adsorption on silica based biomedical devices.
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| 56. |
- Svensson, Olof, et al.
(författare)
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Antibody–antigen interaction on polystyrene : An in situ ellipsometric study
- 2012
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Ingår i: Journal of Colloid and Interface Science. - : Elsevier. - 0021-9797 .- 1095-7103. ; 368:1, s. 533-539
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Tidskriftsartikel (refereegranskat)abstract
- The objective of this investigation was to monitor the adsorption of antibodies to polystyrene surfaces using ellipsometry. Commercial polystyrene slides used for solid state diagnostics were selected as substrates and the adsorption of three different antibodies (human IgG, bovine IgG and goat anti-human IgG) were evaluated. Based on theoretical models describing the ellipsometric data, it was concluded that the adsorption of antibodies should result in layers that are sufficiently thick to be able to monitor the adsorption in terms of adsorbed amount and thickness of the layer with a reasonable precision. The experimental results confirmed this assumption and values of 2.0–2.3 mg/m2 were detected for the adsorbed amount with a corresponding thickness of 10–16 nm. It was furthermore found that the antibodies bound irreversibly with respect to rinsing with protein-free solutions. In additional experiments, the consecutive incubation of human IgG and anti-human IgG was investigated. These results showed that, on average, approximately half of the surface immobilized anti-human IgG molecules are capable of binding to human IgG during its incubation. From the consecutive binding experiments it could also be concluded that antibodies present in the polyclonal anti-human IgG preparation were capable of binding to around four different epitopes on the human IgG. A final set of experiments addressed the stability of adsorbed human IgG layers with respect to drying and incubation with surfactant. The results revealed that the adsorbed antibody layer is relatively resistant to these treatments.
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| 57. |
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| 58. |
- Svensson, Olof, et al.
(författare)
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Mucin layers and multilayers — Physicochemical properties and applications
- 2010
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Ingår i: Current Opinion in Colloid & Interface Science. - : Elsevier. - 1359-0294 .- 1879-0399. ; 15:6, s. 395-405
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Forskningsöversikt (övrigt vetenskapligt/konstnärligt)abstract
- The present review summarizes recent, and important previous, findings on properties of mucin layers and multilayers and ways to tailor their properties. Specifically, progress has been made in understanding the effects of mucin type, preparations, ambient conditions and surface properties on adsorption and on mixed layer assembly including multilayers. Apart from structural features the stability, lubrication and biological functions of such layers are addressed.
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| 59. |
- Svensson, Peter, 1974-
(författare)
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The Dynamics of Innovation and Knowledge-Based Regional Development
- 2010
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Geographical regions as diverse as Silicon Valley, California and Linköping, Sweden have been the sources of new technology and endogenously created innovations. Scholars and policymakers recognise that specific regions or clusters of businesses have the capability to engage in more innovative activities and new business formation and to experience higher employment growth than others. This dissertation uses qualitative methods to study various aspects of regional development and innovation. It is based on five papers by the author and colleagues with levels of analysis ranging from regional to firms’ first sales in order to capture the dynamics of both the top and bottom levels of regional development. It then uses these papers’ empirical material to address the research questions of (a) how a new scientific knowledge base becomes established and exploited in a spatial context, and (b) how people create and diffuse innovations in a social and spatial context. This dissertation’s main findings are that (a) regional leadership involving the building of alliances with triple-helix actors is crucial for initiating a knowledge-based regional development process, (b) a consensus space is a catalytic mechanism for ensuring the speed and effectiveness of regional development, (c) lowering the barriers for the actors involved boosts participation and the rate of innovation, and (d) users’ perspectives are essential for social, institutional and commercial innovation. This dissertation’s main implications are that knowledge-based regional development’s initial stages require leadership that (a) builds alliances and establish an arena for the triple-helix actors, (b) analyses the regional barriers to the commercialisation of knowledge, and (c) utilises both endogenous and exogenous resources.
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| 60. |
- Wikström, Per-Olof, et al.
(författare)
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When does self-control matter? The interaction between morality and self-control in crime causation
- 2010
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Ingår i: European Journal of Criminology. - : Sage Publications. - 1477-3708 .- 1741-2609. ; 7:5, s. 395-410
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Tidskriftsartikel (refereegranskat)abstract
- In this paper we will test one of the key assumptions of Situational Action Theory: that individuals’ (law-relevant) morality is more fundamental to their crime involvement than their ability to exercise self-control. We specifically hypothesize that, for individuals with a strong morality, their capability to exercise self-control plays less of a role in their crime involvement than it does for individuals with a weak morality, whose capability to exercise self-control may substantially influence their engagement in crime. To test this hypothesis we use data from the Peterborough Youth Study (PYS), a cross-sectional survey of 1957 adolescents aged 14—15 from the UK city of Peterborough. The findings support the main hypothesis: young people with a strong (law-relevant) morality do not engage in crime, regardless of their ability to exercise self-control. However, among those with a weaker (law-relevant) morality, their ability to exercise self-control is an important factor in their crime involvement.
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