| 61. |
- Hammarström, Martin, 1973-
(författare)
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Protein production and purification in structural genomics
- 2006
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The number of gene products available for structural and functional study is increasing at an unprecedented rate as a result of the successful whole genome sequencing projects. Systematic structure determination of proteins on a genomic scale, called structural genomics, can significantly contribute to the field of protein science and to functional annotation of newly identified genes. This thesis covers different aspects of protein production in Eschericiha coli for structural studies in the context of structural genomics. Protocols have been downscaled and standardized to allow for a rapid assessment of the production characteristics for multiple proteins in parallel under a number of different conditions. Foremost, the ability of different proteins and peptide tags to affect the solubility of the recombinant protein when produced as fusion proteins has been systematically studied. Large differences in the success-rate for production of soluble protein in E. coli were found depending on the fusion partner used, with a more than two-fold increase in the number of proteins produced as soluble when comparing the best and the poorest fusion tags. For different constructs with a histidine tag, commonly used to facilitate protein purification, large differences in yield depending on the design of the expression vector were found. When comparing different fusion proteins produced from identical expression vectors, fusions to the GB1 domain were found to result in the highest yield of purified target protein, on average 25 % higher than any of the other fusions. The suitability for further structural studies was tested at an intermediate scale for proteins that were identified as soluble in the expression screening. For this purpose, protocols for rapid purification and biophysical characterization using nuclear magnetic resonance and circular dichroism spectroscopy were developed and tested on 19 proteins, of which four were structured.
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| 62. |
- Hart, Andrew R, et al.
(författare)
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Diet in the aetiology of ulcerative colitis: A European prospective cohort study
- 2008
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Ingår i: Digestion. - : S. Karger AG. - 1421-9867 .- 0012-2823. ; 77:1, s. 57-64
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Tidskriftsartikel (refereegranskat)abstract
- Background/Aims: The causes of ulcerative colitis are unknown, although it is plausible that dietary factors are involved. Case-control studies of diet and ulcerative colitis are subject to recall biases. The aim of this study was to examine the prospective relationship between the intake of nutrients and the development of ulcerative colitis in a cohort study. Methods: The study population was 260,686 men and women aged 20-80 years, participating in a large European prospective cohort study (EPIC). Participants were residents in the UK, Sweden, Denmark, Germany or Italy. Information on diet was supplied and the subjects were followed up for the development of ulcerative colitis. Each incident case was matched with four controls and dietary variables were divided into quartiles. Results: A total of 139 subjects with incident ulcerative colitis were identified. No dietary associations were detected, apart from a marginally significant positive association with an increasing percentage intake of energy from total polyunsaturated fatty acids (trend across quartiles OR = 1.19 (95% CI = 0.99-1.43) p = 0.07). Conclusions: No associations between ulcerative colitis and diet were detected, apart from a possible increased risk with a higher total polyunsaturated fatty acid intake. A biological mechanism exists in that polyunsaturated fatty acids are metabolised to pro-inflammatory mediators.
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| 63. |
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| 64. |
- Holmberg, Anna H, et al.
(författare)
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Risk factors for hip fractures in a middle-aged population: a study of 33,000 men and women.
- 2005
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Ingår i: Osteoporosis International. - : Springer Science and Business Media LLC. - 1433-2965 .- 0937-941X. ; 16:Sep22, s. 2185-2194
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Tidskriftsartikel (refereegranskat)abstract
- Knowledge about subjects who sustain hip fractures in middle age is poor. This study prospectively investigated risk factors for hip fracture in middle age and compared risk factors for cervical and trochanteric hip fractures. The Malmo Preventive Project consists of 22,444 men, mean age 44 years, and 10,902 women, mean age 50 years at inclusion. Baseline assessment included multiple examinations and lifestyle information. Follow-up was up to 16 years with regard to occurrence of fracture. One hundred thirty-five women had one low-energy hip fracture each, 93 of which were cervical and 42 trochanteric. One hundred sixty-three men had 166 hip fractures, of which 81 were cervical and 85 trochanteric. In the final Cox regression model for women, the risk factors with the strongest associations with hip fracture were diabetes (risk ratio (RR) 3.89, 95% confidence interval (CI) 1.69-8.93, p=0.001) and poor self-rated health (RR 1.74, 95% CI 1.22-2.48, p=0.002). A history of previous fracture (RR 4.76, 95%CI 2.74-8.26, p=0.0001) was also a significant risk factor. In men, diabetes had the strongest association with hip fracture (RR 6.13, 95%CI 3.19-11.8, p=0.001). Smoking (RR 2.20, 95%CI 1.54-3.15, p=0.001), high serum gamma-glutamyl transferase (RR 1.84, 95%CI 1.50-2.26, p=0.001), poor self-rated health (RR 1.49, 95%CI 1.06-2.10, p=0.02) and reported sleep disturbances (RR 1.52, 95%CI 1.03-2.27, p=0.04) were other significant risk factors. The strongest risk factor for hip fracture for both women and men in middle age was diabetes. Many risk factors were similar for men and women, although the risk ratio differed. The risk factor pattern for cervical versus trochanteric fractures differed in both men and women. The findings indicate that those suffering a hip fracture before the age of 75 have a shorter life expectancy, suggesting that hip fractures affect the less healthy segment of the population.
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| 65. |
- Hulterström, Anna Karin, 1952-
(författare)
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Silicone obturators and the bacterial flora in symptomatic nasal septal perforations
- 2012
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Background A perforation in the nasal septum can cause symptoms such as bleeding, obstruction, crusts and pain, and can be a challenge to treat. Surgery is the treatment of choice, but disease, size of the perforation, or the patient’s wish may contradict surgery. A custom-made silicone obturator is a successful treatment option, but little is known how this treatment affects the microbial flora. The purposes of this thesis were (i) to investigate the microbial flora around symptomatic nasal septal perforations before treatment, (ii) during and after a 12-month treatment period with a custom-made obturator, (iii) to compare the microbial flora around symptomatic perforations with the flora from the same area of the septum in healthy individuals, (iv) to investigate the microbial colonization of the silicone obturator, and (v) also to investigate the water sorption, solubility and if the wettability of silicones are affected by water. The hypotheses were (i) that the bacterial flora around symptomatic perforations would not differ from that found in healthy individuals, apart from a possible presence of Helicobacter pylori; (ii) the bacterial flora would change in composition during the course of treatment and that microorganisms and proteins could be seen on the surface of the silicone obturators; (iii) a material that has adsorbed water would also show an increase in wettability and the surface free energy of the material. Methods Twenty-seven patients and 101 healthy individuals volunteered. Swabs were made around the rim of the perforation, or on the septum in the locus Kisselbachi area in the healthy individuals. Bacteria and fungi were isolated and identified with standard laboratory techniques. A biopsy of the granulated tissue at the perforation was taken and cultivated for Helicobacter pylori. Swabs were also taken three, six and twelve months after inserting the obturator. The obturator was analysed after being used twelve months in the nose. Seven silicones were tested for water sorption and solubility according to ISO standards 1567:1999 and ISO 10477:2004. The change in wettability was examined by measuring the contact angle with a contact goniometer at various stages of the sorption/solubility test.Results Staphylococcus aureus was present in 88% of the untreated patients. With treatment a significant reduction of S. aureus occurred to 54.5% (p<0.05). In the healthy group S. aureus was present in 13% of the subjects. No Helicobacter pylori could be cultivated from the biopsies taken of the granulated tissue at the perforation. The flora round the untreated perforation was dominated by S. aureus with few other bacterial species detected. In the healthy group there was a diversified flora with both aerobic and anaerobic bacteria. SEM revealed a rough surface on the silicone obturator and crazing of the silicone surrounding the pigment granules. Both bacteria and proteins could be seen on the obturators in SEM. Candida albicans was detected in one obturator, but not in the mucosal swab at the corresponding time. That patient had, however, been treated for Candida in the nose six months prior to the last visit in the study. Wettability was affected but did not increase with amount of adsorbed water. Some materials showed an increase and some a decrease in the surface-free energy. The tested addition silicones showed little sorption and solubility.Conclusions The patients with symptomatic perforations of the nasal septum had a bacterial flora totally dominated by S. aureus. The massive presence of S. aureus around symptomatic perforations may have an impact on the persistence of the granulated and inflamed tissue present in symptomatic perforations, thus forming a vicious circle with bleeding and crustation.S. aureus dominance in the mucosa surrounding symptomatic perforations was diminished by using a custom-made obturator. The microbial flora became more diversified with the treatment, although not resembling the flora in healthy individuals. The microbial flora of the obturators was similar, but not the same as the corresponding mucosal flora. The discovery of Candida in the obturator of a patient who had been treated for Candida in the nose six months earlier suggests that obturators need to be exchanged when fungal infections are being treated to prevent the fungus from re-infecting the patient at a later stage.The silicone had a rough surface and a poor wettability, both aspects favours colonization of microorganisms. The silicone was negatively affected by the colouring pigments, this should be considered when colouring is not necessary. The slight, but existing solubility of silicones emphasises the importance of using medical grade silicones that are more purified than industrial silicones.
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| 66. |
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| 67. |
- Ingerman, Åke, 1973, et al.
(författare)
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On the exploration, expansion and expression of experiencing technological systems across contexts: learning technology in the Swedish compulsory school
- 2012
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Ingår i: The EARLI SIG9 conference, Jönköping, Sweden, 27-28 August 2012.
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Konferensbidrag (refereegranskat)abstract
- In the phenomenographic tradition, the process of learning is usually described as becoming capable of discerning a phenomenon in qualitatively new ways. In a project that focuses on what it takes and means to learn technological systems, we will study the relationship between learning in this sense, and the variation and invariance in the moment-to-moment manifestation of such an emerging capability. The object of learning, technological systems, comprises complex systems of technical and human components that facilitate much of the experienced needs of modern society, constituted of the transformation and transport of matter, energy and information. The context of the study is the Swedish compulsory school. To allow for such a detailed investigation, the empirical design includes a teaching plan, jointly developed by involved teachers and researchers, which leads to a variation of pedagogical activities across contexts in which different technological systems may be encountered. The design includes the collection and analysis of video and audio data, and discussions with teachers and students. The different communicative situations which focus on technological systems are bound together by the individuals involved, who are working, collaboratively as well as individually, to develop their experience of technological systems. The presentation focus challenges and open questions.
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| 68. |
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| 69. |
- Ingerman, Åke, 1973, et al.
(författare)
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Technological systems across contexts: Designing and exploring learning possiblities in Swedish compulsory technology education
- 2012
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Ingår i: Technology Education in the 21st Century, Proceedings from the PATT 26 Conference, Stockholm, Sweden 26-30 June 2012, Edited by Thomas Ginner, Jonas Hallström, Magnus Hultén. - 1650-3740. - 9789175198491 ; , s. 232-238
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Konferensbidrag (refereegranskat)abstract
- In the world we live in there are powerful broad frameworks for understanding specific objects, relationships and events. This paper focuses the learning and understanding of one such frame- work, namely, technological systems, which are complex systems of technical and human compo- nents that facilitate much of the experienced needs of modern society. Technological systems are constituted of transformation and transport, acting on matter, energy and information. This paper outlines a larger project, which is expected to contribute substantially to a pedagogical knowledge base for systems thinking in technology. The specific focus of the paper will be the first step in the project – the development of a design for learning technological systems in Swedish compulsory school based on previous empirical studies as well as theoretical principles. The core of that design revolves around creating patterns of variation supporting the separation and differentiation in and between four empirically identified dimensions of variation: resource, intention, internal struc- ture and external structure. It also includes patterns of variation that support the fusion of these dimensions and simultaneous awareness of several different technological systems, focusing their systemic nature.
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| 70. |
- Ingerman, Åke, 1973, et al.
(författare)
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The focus of phenomenography: the phenomenon and the object of learning
- 2014
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Ingår i: Presentation at the EARLI SIG9 conference ”Disciplinary Knowledge and Necessary Conditions of Learning”, Oxford, September 1-3.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Phenomenographic studies normally aim towards exploring different ways of experiencing or understanding a phenomenon. There is an explicit claim that these ways of experiencing capture what the phenomenon may look like from the point of view of the students (or experiencers), rather than what the phenomenon is per se (ontologically or epistemologically). Studies based on the variation theory of learning, and in particular learning studies, rather refer to the object of learning as the relevant point of experiential reference in processes of learning and classroom teaching. The object of learning is generally identified and delimited by the teachers. It can be argued that the “success” of a learning study in a way can be measured by the alignment of the intended, enacted and experienced object of learning. Thus, there are succinct differences in perspective (student vs teacher) between phenomenon and object of learning. In this discussion we explore overlaps and tensions between them in relation to the ambition of analytically addressing empirical data from students discussing in groups with and without the teacher as a part of classroom teaching. Phenomena as emergent in such discussion may then be constituted differently and as distinct from the object of learning (and not reducible to the lived object of learning). Theoretical and empirical considerations are done.
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