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- Edman, Anne-Christine, 1946-
(författare)
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Myofibrillens finstruktur i tvärstrimmig skelettmuskulatur
- 1988
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The detailed structure of the myofibrillar material in fibres from different muscles has been studied. Specimens have been obtained from human muscles and from different muscles frequently examined in experimental studies. Both light- and electron microscopical techniques have been used. Of central importance has been the method, which makes it possible to prepare ultrathin sections of frozen tissue, i.e. cryo-ult- ramicrotomy. A number of techniques for image analysis have been applied in order to obtain objektive data from the micrographs.In Paper I the present knowledge about muscle fibre structure, cryo-- sectioning and image analysis is summarized and relevant methodological problems are discussed. Paper II describes the detailed structure of the C-zone of the A-band and shows, above all, that structures occur with different repeats along the long axis of the myofibril. Paper III describes the subcellular organization of different fibres in a homogeneous (based on enzyme histochemical mATPase) population, and shows that different structural characteristies can vary independently of each other. Paper IV describes the structural diversity of the myofibrillar M-band, and paper V the diversity of the myofilament fine structure in different fibres. The results show that there is a most sophisticated, and previosly unrealized, structural specialization both within the myofibrils and between myofibrils from different fibres and muscles, even if the fibres are of the same fibre type. The findings suggest that generally used models, showing the structural organization within myofibrils and myofilaments, are oversimplifications. The fibre population is more heterogeneously built up than the common systems for fibre type classification makes one to belive.
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| 2. |
- Hallström, Lena, 1958-
(författare)
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Breakfast habits among European adolescents : The Healthy Lifestyle in Europe by Nutrition in Adolescence (HELENA) Study
- 2011
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The aim of this thesis was to study the associations of individual and socio-environmental factors with breakfast habits among adolescents on a European level. Methods: The HELENA-study (Healthy Lifestyle in Europe by Nutrition in Adolescence) is a multi-centre cross-sectional, school-based study including 3528 adolescents (aged 12.5-17.49 years) from 10 European cities inEurope. Data was collected during the 2006-2007 academic year. Breakfast habits were assessed by a computerised, self-administered, 24-h recall and by questionnaires. The whole day dietary intake, measured with the computerised 24-h recall, was evaluated by comparing a self-administered and an interviewed 24-h recall. The socio-demographical factors used were sex, age, region inEurope (southern versus northern/central), mother and father’s education and occupation, family structure and family affluence. Body composition was measured with weight, height, waist circumference and skinfold thickness. Blood pressure, cardiorespiratory fitness, blood lipids, insulin and glucose were also measured. Results: The evaluation between the self-administered and interview 24-h recall showed generally good agreement between the two methods. Few adolescents (4 %) had a ‘high-quality’ breakfast. Breakfast consumption on both recall days was reported among 77 % (24-h recall) and 55 % reported slightly disagreeing to strongly disagreeing with the statement ‘I often skip breakfast’. Younger adolescents, adolescents from the northern/central part of Europe and adolescents from families with high socio-demographical status were more likely to report consuming a ‘high-quality’ breakfast while breakfast consumption versus breakfast skipping were inappreciably associated with socio-demographical factors. Personal factors (‘hunger’, ‘taste of the food’ ‘concern for health’) and the socio-environmental factor (‘parents or guardian’) were the most important influences on the adolescents’ choice of food at breakfast. Regular ‘breakfast consumption’ was associated with higher cardiorespiratory fitness in both boys and girls, and with a healthier cardiovascular profile, especially in boys. Conclusion: The public health implications of poor breakfast consumption habits are considerable. This work highlights the need to promote breakfast, especially a ‘high-quality’ breakfast, among adolescents, particularly older adolescents, adolescents from the southern part of Europe and adolescents from families with low socio-demographical status.
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| 3. |
- Olsson, Ing-Marie, 1978-
(författare)
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Experimental Designs at the Crossroads of Drug Discovery
- 2006
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- New techniques and approaches for organic synthesis, purification and biological testing are enabling pharmaceutical industries to produce and test increasing numbers of compounds every year. Surprisingly, this has not led to more new drugs reaching the market, prompting two questions – why is there not a better correlation between their efforts and output, and can it be improved? One possible way to make the drug discovery process more efficient is to ensure, at an early stage, that the tested compounds are diverse, representative and of high quality. In addition the biological evaluation systems have to be relevant and reliable. The diversity of the tested compounds could be ensured and the reliability of the biological assays improved by using Design Of Experiments (DOE) more frequently and effectively. However, DOE currently offers insufficient options for these purposes, so there is a need for new, tailor-made DOE strategies. The aim of the work underlying this thesis was to develop and evaluate DOE approaches for diverse compound selection and efficient assay optimisation. This resulted in the publication of two new DOE strategies; D-optimal Onion Design (DOOD) and Rectangular Experimental Designs for Multi-Unit Platforms (RED-MUP), both of which are extensions to established experimental designs. D-Optimal Onion Design (DOOD) is an extension to D-optimal design. The set of possible objects that could be selected is divided into layers and D-optimal selection is applied to each layer. DOOD enables model-based, but not model-dependent, selections in discrete spaces to be made, since the selections are not only based on the D-optimality criterion, but are also biased by the experimenter’s prior knowledge and specific needs. Hence, DOOD selections provide controlled diversity. Assay development and optimisation can be a major bottleneck restricting the progress of a project. Although DOE is a recognised tool for optimising experimental systems, there has been widespread unwillingness to use it for assay optimisation, mostly because of the difficulties involved in performing experiments according to designs in 96-, 384- and 1536- well formats. The RED-MUP framework combines classical experimental designs orthogonally onto rectangular experimental platforms, which facilitates the execution of DOE on these platforms and hence provides an efficient tool for assay optimisation. In combination, these two strategies can help uncovering the crossroads between biology and chemistry in drug discovery as well as lead to higher information content in the data received from biological evaluations, providing essential information for well-grounded decisions as to the future of the project. These two strategies can also help researchers identify the best routes to take at the crossroads linking biological and chemical elements of drug discovery programs.
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| 4. |
- Winberg, Mikael, 1963-
(författare)
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Simulation in university chemistry education : cognitive and affective aspects
- 2006
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis undertakes two main tasks; to explore, within the authentic educational context, variables that influence the quality and outcomes of the knowledge-constructing activity during the simulation exercise; and to find appropriate instruments and methods to measure these variables, processes and outcomes. Closed-ended tasks that provided a high degree of structure, i.e., supported students’ regulation of learning during the simulation exercise, were more beneficial for perceived improvement of declarative knowledge and students’ motivation than open-ended tasks. Open-ended tasks did however lead to substantial shifts in students’ cognitive focus in subsequent laboratory exercises and improvement of students’ level of chemistry reasoning in interviews. Student attitudes toward learning proved important in the first paper where significantly higher ability to apply chemistry knowledge in interviews could be found for students with relativistic attitudes compared to those with more dualistic perspectives on learning. In the subsequent papers, the effects of attitudes were not as clear, possibly due to too small differences in the learning situations that were compared. Quality of the learning discourse during simulation was measured with three qualitatively different methods, focusing on partly different aspects. The different methods gave very similar results regarding the relative quality of the discourses. Thus, “quality” as such seems to be an underlying feature that permeates many aspects of the discourse and consequently could be targeted in different ways, e.g., focusing on quantitative as well as qualitative aspects. The analyses revealed several components of quality; co-operative activity, correctness and complexity of chemistry reasoning, discussion length and intensity, ability to realize cognitive conflict, and reference to theory while reasoning. Doing the simulation exercise in a distributed learning setting (written e-communication), supported discussions with higher accuracy and complexity of chemistry reasoning and frequent references to theory while the face-to-face situation allowed for longer and more intense discussions and a higher degree of co-operative activity. Not very surprisingly, high-quality discussions were characterized by high scores in all these components. There were indications that relatively good pre-knowledge might be required to benefit fully from face-to-face discussions. The validity of instruments and methods, used to measure flow experiences, attitudes (i.e., epistemological beliefs), knowledge accessibility (intuitive knowledge) and discourse quality are discussed thoroughly. Special interest has been devoted to whether qualitative data should be quantified or not, providing arguments in favor of quantitative methods for analyzing and reporting qualitative data.
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