| 41. |
- Elg, Mattias, 1968-, et al.
(författare)
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Sustainable working life development through interactive research
- 2018
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Ingår i: PIN-C Conference Proccedings. ; , s. 1-5
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Interactive research has emerged as a new approach to collaborative research in working life research, and it is characterized by a continuous joint learning process between the researchers and the practitioners. In this paper we argue that interactive research is a way to advance scientific knowledge about the development of new types of work arrangements and development of sustainable working life. We present the basic ideas and benefits of the interactive research approach, illustrated through a practical case, the HELIX Competence Centre and discuss potential limitation and challenges associated with this form of collaborative research.
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| 42. |
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| 43. |
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| 44. |
- Engelmark Cassimjee, Karim
(författare)
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ω-Transaminase in Biocatalysis : Methods, Reactions and Engineering
- 2012
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Biocatalysis offers an alternative to classic chemistry by using enzymes, the protein catalysts of Nature, for production of fine chemicals. Evolution has created enzymes capable of catalysis at moderate temperature of a specific reaction in the presence of a plethora of compounds in the aqueous cell environment. The focal point of biocatalysis is to utilise these traits in vitro, for creation of valuable molecules. The ω-transaminase is an enzyme capable of producing chiral amines, compounds used to great extent in pharmaceuticals. Much effort has in recent years been invested in the research and engineering of this enzyme type since the catalysed reaction offers an advantageous alternative to classical techniques. Nevertheless, there is a need for method development, adaptation of the enzyme and increased understanding of the catalytic mechanism for feasibility as an effective biocatalyst for unnatural substrates. This thesis addresses a chosen set of obstacles as a contribution to meeting the demands at hand. ω-Transaminase from Chromobacterium violaceum and Arthrobacter citreus was used. Many homologous ω-transaminases are available, which are also subject to engineering where variants are produced. To accurately compare their kinetic constants an active site quantification method is required but has not been available. Here such a method is presented (Paper 1) which encompasses a virtually irreversible half transamination reaction. In stereoselective synthesis the ω-transaminase catalysed equilibrium reaction inherently results in incomplete conversion. An equilibrium displacement system is presented (Paper II) where isopropylamine is the amino donor for transamination of acetophenone and derivatives thereof, coupled to an enzymatic cascade reaction. For many unnatural substrates the specificity and enantiospecificity is insufficient. Rationally redesigned variants were produced with improved properties for chosen substrates (Paper III and IV). The catalytic contributions of field and resonance of a variant compared to the wild type were investigated (Paper IV) for increased knowledge of the mechanism. For rational redesign of an enzyme the three-dimensional structure is required, of which only a few are available for the ω-transaminases. X-ray crystallographic structures of the holo and apo form of Chromobacterium violaceum ω-transaminase were made (Paper V) which revealed significant structural rearrangements upon coenzyme binding which may be of consequence for future engineering.
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| 45. |
- Ericsson, Mikael, 1975-, et al.
(författare)
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Three Dimensional Simulation of Robot path, Heat Transfer and Residual Stresses of a TIG-welded Part with Complex Geometry
- 2002
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Ingår i: Trends in Welding Research: Proceedings of the 6th International Conference. ; , s. 973-978
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- In this paper a system is presented that combines a robot off-line programming software with a finite element model that predicts temperature-time histories and residual stress distributions. The objective is to develop a tool for the engineer where robot trajectories and welding process parameters can be optimized on parts with complex geometry. The system was evaluated on a stainless steel gas turbine component. Robot weld paths were defined off-line and automatically downloaded to the finite element program, where transient temperatures and residual stresses were predicted. Temperature dependent properties and phase change, were included in the analysis. Assumptions and principles behind the modeling techniques are presented together with predicted temperature histories, residual stresses, and fixture forces.
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| 46. |
- Eriksson, Ulrika, 1974-
(författare)
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Impact of autocrine factors on physiology and productivity in Trichoplusia ni serum-free cultures
- 2005
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The aim of this study was to increase the understanding of the mechanisms regulating cell proliferation and recombinant protein production in serum-free cultures of Trichoplusia ni (T. ni) insect cells.Conditioned medium (CM) was shown to contain both stimulatory and inhibitory factors (CM factors) influencing cell growth. Metalloproteinase (MP) activity was the major factor responsible for the growth stimulating effect of CM as shown by using the specific MP inhibitor DL-thiorphan. MPs may exist in several different molecular mass forms due to autoproteolysis. Although the main band of the MP was determined to be around 48 kDa, precursor forms above 48 kDa as well as autocatalytic degradation products below the main band could be observed. It is not clear whether all forms of the MP or just the main band is involved in the growth regulation. Further, a proteinase inhibitor could be identified in the inhibitory fraction. Thus, we speculate that the proteinase inhibitor may be part of an autocrine system regulating cell proliferation.Analysis of the cell cycle phase distribution revealed a high proportion of cells in the G1 (80-90 %) and a low proportion of cells in the S and G2/M phases (10-20 %) during the whole culture, indicating that S and G2/M are short relative to G1. After inoculation, a drastic decrease in the S phase population together with a simultaneous increase of cells in G1 and G2/M could be observed as a lagphase on the growth curve and this may be interpreted as a temporary replication stop. When the cells were released from the initial arrest, the S phase population gradually increased again. This was initiated earlier in CM-supplemented cultures, and agrees with the earlier increase in cell concentration. Thus, these data suggests a correlation between CM factors and the cell cycle dynamics.In cultures supplied with CM, a clear positive effect on specific productivity was observed, with a 30 % increase in per cell productivity. The specific productivity was also maintained at a high level much longer time than in fresh-medium cultures. The positive effect observed after 20 h coincided with the time a stimulatory effect on cell growth first was seen. Thus, the productivity may be determined by the proliferation potential of the culture. A consequence of this would be that the secreted MP indirectly affects productivity.Finally, the yeast extract from Express Five SFM contains factors up to 35 kDa which are essential for T. ni cell growth. The optimal concentration was determined to be 2.5-fold that in normal medium, while higher concentrations were inhibitory. However although vital, they were not solely responsible for the growth-enhancing effect, as some other, more general, component present in yeast extract was needed for proliferation as well.
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| 47. |
- Fasth Berglund, Åsa, 1978, et al.
(författare)
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SMARTARE MÖTEN MEET-MODELLEN
- 2016
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- MEET-modellen bidrar till ett mer strukturerat arbete gällande organisations- och informationsstruktur när olika former av möten skall planeras. Målet är effektivare möten, bättre vägval gällande organisatoriska och informatoriska frågor, ökat informations- och kunskapsspridande i organisationen samt att gå från individuellt till organisatoriskt lärande.
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| 48. |
- Fridén, Michael, et al.
(författare)
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Effects of a low-carbohydrate high polyunsaturated fat diet or a healthy Nordic diet versus usual care on liver fat content and cardiometabolic risk factors in people with type 2 diabetes and prediabetes: a randomized controlled trial (NAFLDiet)
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Background: Previous trials have shown that plant-derived polyunsaturated fatty acids (PUFA) in place of saturated fat reduces liver fat, a prerequisite for non-alcoholic fatty liver disease (NAFLD). The effect on liver fat from a novel “anti-lipogenic diet” replacing carbohydrates with PUFA or a healthy Nordic diet (HND) higher in whole-grains but lower in saturated fat has not yet been examined. Objectives: To investigate the effects on changes in liver fat (primary outcome) and other cardiometabolic risk factors after 12 months of follow-up in individuals with prediabetes or T2D from three different diet comparisons: a low carbohydrate high PUFA (LCPUFA) diet versus a HND, a LCPUFA diet versus usual care (UC) and a HND versus UC. Methods: A three-arm parallel ad libitum randomized trial was conducted. Adult men and women (n=148) were randomized to one of the three diet groups. Participants in all groups received key food items on a monthly/bimonthly basis. Liver fat and cardiometabolic risk factors were assessed at baseline and after 12 months. Dietary adherence was assessed using weighed food diaries and objective biomarkers. General linear models were employed to estimate the intention-to-treat (ITT) effect. Results: Dietary adherence was high for all diet groups. Liver fat was reduced to a similar extent in the LCPUFA and the HND group compared to UC (-1.46% (95% CI: -2.42, -0.51)) and -1.76 % (95% CI: -2.96, -0.57), respectively. No difference in liver fat between LCPUFA and HND was observed. Body weight and HbA1c decreased more in the HND compared to the other diet groups whereas no differences were observed between LCPUFA and UC. Similar reductions in LDL-cholesterol were observed for the HND and the LCPUFA group compared to UC, but only the HND reduced triglycerides and C-reactive protein (CRP) compared with UC. No differences were observed for any other secondary outcomes.Conclusions: A LCPUFA diet and a HND both reduced liver fat as compared with UC. Given the sustained weight loss after the HND compared to the other groups, together with improvements in other cardiometabolic markers, the HND in particular seems to be useful for the treatment of T2D and NAFLD.
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| 49. |
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| 50. |
- Gustavsson, Martin, 1984-
(författare)
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Surface expression using the AIDA autotransporter : Towards live vaccines and whole-cell biocatalysis
- 2011
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The area of surface expression has gathered a lot of interest from research groups all over the world and much work is performed in the area. Autotransporters have been used for surface expression in Gram-negative bacteria. One of the more commonly used autotransporters is the Adhesin Involved in Diffuse Adherence (AIDA) of pathogenic Escherichia coli. The surface expression of enzymes and vaccine epitopes offer several advantages. Surface expressed enzymes gain similar properties to immobilised enzymes, mainly simplified handling and separation using centrifugation. Surface expressed vaccine epitopes can have longer half-lives inside the animal that is to be immunized and surface groups on the host cell can act as adjuvants, increasing the immune response and leading to a better immunisation. However, while much basic research is directed towards mechanisms of surface expression using autotransporters there are few reports regarding production of surface expressed protein. Thus the aim of this work was the optimisation of the yield and productivity of surface expressed protein. Protein Z, an IgG-binding domain of Staphylococcal protein A, was used as a model protein for the investigation of which cultivation parameters influenced surface expression. The choice of cultivation medium gave the largest impact on expression, which was attributed to effects based on the induction of the native promoter of AIDA. The AIDA system was then used for the expression of two Salmonella surface proteins, SefA and H:gm, with potential for use as vaccine epitopes. SefA was verified located on the cell surface, and H:gm was found in the outer membrane of the host cell, though only in proteolytically truncated forms lacking the His6-tag used for detection. This proteolysis persisted in E. coli strains deficient for the outer membrane protease OmpT and was concluded to be dependent on other proteases. The removal of proteolysis and further optimisation of the yield of surface-expressed protein are important goals of further work.
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