| 1. |
- Aarts, Clara
(författare)
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Exclusive breastfeeding-Does it make a difference? : A longitudinal, prospective study of daily feeding practices, health and growth in a sample of Swedish infants
- 2001
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The concept of exclusive breastfeeding in relation to daily feeding practices and to health and growth of infants in an affluent society was examined. In a descriptive longitudinal prospective study 506 mother-infant pairs were followed from birth through the greater part of the first year. Feeding was recorded daily, and health and growth were recorded fortnightly. Large individual variations were seen in breastfeeding patterns. A wide discrepancy between the exclusive breastfeeding rates obtained from "current status" data and data "since birth" was found.Using a strict definition of exclusive breastfeeding from birth and taking into account the reasons for giving complementary feeding, the study showed that many exclusively breastfed infants had infections early in life, the incidence of which increased with age, despite continuation of exclusive breastfeeding. However, truly exclusively breastfed infants seem less likely to suffer infections than infants who receive formula in addition to breast milk. Increasing formula use was associated with an increasing likelihood of suffering respiratory illnesses. The growth of exclusively breastfed infants was similar to that of infants who were not exclusively breastfed. The health of newborn infants during the first year of life was associated with factors other than feeding practices alone. Some of these factors may be prenatal, since increasing birth weight was associated with an increasing likelihood of having respiratory symptoms, even in exclusively breastfed infants. However, exclusive breastfeeding was shown to be beneficial for the health of the infant even in an affluent society.
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| 2. |
- Abrahamson, Magnus, 1972-
(författare)
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Jesu uppståndelse som historiskt problem : En studie av Rudolf Bultmanns och Wolfhart Pannenbergs tolkningar
- 2001
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The main purpose of this study is to make a critical examination of Rudolf Bultmann´s (1884–1976) and Wolfhart Pannenberg´s (b. 1928) interpretations of the resurrection of Jesus. Bultmann is best known for seeking to demythologize the miracles of the New Testament. Pannenberg has gained much attention for arguing that the resurrection of Jesus is an event in chronological history. In this thesis I first present Bultmann´s and Pannenberg´s interpretations of the resurrection of Jesus. In order to help the reader understand the context in which these interpretations were made, I give a brief sketch of the German theological setting. Second, I compare the theologies of Bultmann and Pannenberg from the concept of background theory, principles of interpretation, exegetical reasoning, the meaning of the resurrection and what it means to accept the resurrection. Third, I categorize different ways that the resurrection could be interpreted today. Fourth, I critically discuss the way that Bultmann and Pannenberg argue and give some proposals for how their theologies can be developed. Developing the theology of Bultmann I give more attention to chronological history than he does. I also make alterations in the way he understands God´s action. Concerning Pannenberg I discuss the importance of rational arguments in his theology. I argue that the resurrection should be interpreted from the perspective of a faith or an interpretation which seeks understanding.
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| 3. |
- Abrahamsson, Malin L. A.
(författare)
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Electron Transfer in Ruthenium-Manganese Complexes for Artificial Photosynthesis : Studies in Solution and on Electrode Surfaces
- 2001
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In today’s society there is an increasing need for energy, an increase which for the most part is supplied by the use of fossil fuels. Fossil fuel resources are limited and their use has harmful effects on the environment, therefore the development of technologies that produce clean energy sources is very appealing. Natural photosynthesis is capable of converting solar energy into chemical energy through a series of efficient energy and electron transfer reactions with water as the only electron source. Thus, constructing an artificial system that uses the same principles to convert sunlight into electricity or storable fuels like hydrogen is one of the major forces driving artificial photosynthesis research.This thesis describes supramolecular complexes with the intention of mimicking the electron transfer reactions of the donor side in Photosystem II, where a manganese cluster together with a tyrosine catalyses the oxidation of water. All complexes are based on Ru(II)-trisbipyridine as a photosensitizer that is covalently linked to electron donors like tyrosine or manganese. Photochemical reactions are studied with time-resolved transient absorption and emission measurements. Electrochemical techniques are used to study the electrochemical behavior, and different photoelectrochemical techniques are used to investigate the complexes adsorbed onto titanium dioxide surfaces. In all complexes, intramolecular electron transfer occurs from the linked donor to photo-oxidized Ru(III). It is also observed that coordinated Mn(II) quenches the excited state of Ru(II), a reaction that is found to be distance dependent. However, by modifying one of the complexes, its excited state properties can be tuned in a way that decreases the quenching and keeps the electron transfer properties. The obtained results are of significance for the development of multinuclear Ru-Mn complexes that are capable of multi-electron transfer.
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| 4. |
- Abramson, Jeff
(författare)
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Structural studies on the integral membrane protein, ubiquinol oxidase from Escherichia coli
- 2001
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Heme-copper oxidases are redox-driven proton pumps that couple the reduction of molecular oxygen to water with the vectorial translocation of protons across the membrane. The proton gradient generated by heme-copper oxidases and the other members of the aerobic respiratory chain is ultimately used to drive the synthesis of ATP. There are two main branches of the heme-copper oxidases that are characterized by the electron donating substrate; the cytochrome c oxidases, which use cytochrome c as the electron donor, and the ubiquinol oxidases, which use a lipid-soluble molecule, ubiquinol, as their electron donor. These enzymes share important structural and functional features. This thesis presents the procedures that have led to the first crystal structure of a ubiquinol oxidase, cytochrome bo, oxidase from Escherichia coli, at a resolution of 3.5 Å. The overall structure of the enzyme is similar to those of cytochrome c oxidases; however the membrane spanning region of subunit I contains a cluster of polar residues exposed to the interior of the lipid bilayer. No such structural feature is present in cytochrome c oxidases. Mutagenesis studies on residues in this region strongly suggest that this area forms a ubiquinone binding site. A comparison of this region with known ubiquinone binding sites shows remarkable similarities. In light of these findings specific roles for these polar residues is proposed in electron and proton transfer in ubiquinol oxidase. A fusion protein of cytochrome bo3-Protein Z was generated in an attempt to increase the hydrophilic surface of the protein, thus extending protein-protein contacts within the crystal lattice structure. Such an approach can be used to facilitate crystallization.
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| 5. |
- Ahmed, Meftun
(författare)
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Oscillatory Ca2+ signaling in glucose-stimulated murine pancreatic β-cells : Modulation by amino acids, glucagon, caffeine and ryanodine
- 2001
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Oscillations in cytoplasmic Ca2+ concentration ([Ca2+]i) is the key signal in glucose-stimulated β-cells governing pulsatile insulin release. The glucose response of mouse β-cells is often manifested as slow oscillations and rapid transients of [Ca2+] i. In the present study, microfluorometric technique was used to evaluate the role of amino acids, glucagon, ryanodine and caffeine on the generation and maintenance of [Ca2+] i oscillations and transients in individual murine β-cells and isolated mouse pancreatic islets. The amino acids glycine, alanine and arginine, at around their physiological concentrations, transformed the glucose-induced slow oscillations of [Ca2+] i in isolated mouse β-cells into sustained elevation. Increased Ca2+ entry promoted the reappearance of the slow [Ca2+] i oscillations. The [Ca2+] i oscillations were more resistant to amino acid transformation in intact islets, supporting the idea that cellular interactions are important for maintaining the oscillatory activity. Individual rat β-cells responded to glucose stimulation with slow [Ca2+] i oscillations due to periodic entry of Ca2+ as well as with transients evoked by mobilization of intracellular stores. The [Ca2+] i oscillations in rat β-cells had a slightly lower frequency than those in mouse β-cells and were more easily transformed into sustained elevation in the presence of glucagon or caffeine. The transients of [Ca2+] i were more common in rat than in mouse β-cells and often appeared in synchrony also in cells lacking physical contact. Depolarization enhanced the generation of [Ca2+] i transients. In accordance with the idea that β-cells have functionally active ryanodine receptors, it was found that ryanodine sometimes restored oscillatory activity abolished by caffeine. However, the IP3 receptors are the major Ca2+ release channels both in β-cells from rats and mice. Single β-cells from ob/ob mice did not differ from those of lean controls with regard to frequency, amplitudes and half-widths of the slow [Ca2+] i oscillations. Nevertheless, there was an excessive firing of [Ca2+] i transients in the β-cells from the ob/ob mice, which was suppressed by leptin at close to physiological concentrations. The enhanced firing of [Ca2+] i transients in ob/ob mouse β-cells may be due to the absence of leptin and mediated by activation of the phospholipase C signaling pathway.
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| 6. |
- Alm Kübler, Kerstin
(författare)
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Holocene Environmental Change of Southern Öland, Sweden
- 2001
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis describes Holocene environmental change in Ottenby, southern Öland,Sweden. Analyses of pollen sequences collected distally in the Littorina ridge and in fentroughs between lower laying beach ridges show the vegetation history during twoperiods, the first around 8000 BP and the second from 0/500 AD to about present time.Ages were obtained by radiocarbon datings.The sediments reveal the approaching Littorina transgression. A pond was formedbehind anearlier ridge, and the Littorina ridge was deposited above the organic sequence in thepond. At this time(8000 BP) the vegetation was dominated by deciduous forests of an open character.The sequences from the series of fens formed within the system of beach ridgesreveal the natureof late Holocene environmental change. During the centuries before the Viking Agecattle-breeding was important and open grasslands created by grazing prevailed.Utilization of landscape resources increased as the population increased, and a Callunaheath developed around 800 AD. This shows that under special conditions a heath candevelop in an area with low precipitation if the human impact is heavy enough.In 1546 King Gustav Vasa declared Ottenby a Royal Estate and evicted thepopulation from Ottenby village. The Ottenby area was then governed as one coherentunit. This relieved pressure on the landscape and the modern landscape came into being.The pollen sequences corresponding to the time c. 1500 AD and onwards are inaccordance with the information in the written sources.This study also shows that Fagus sylvatica most probably grew on southern Ölandduring the Middle Ages.
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| 7. |
- Alterman, Mathias
(författare)
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Design and synthesis of HIV-1 protease inhibitors
- 2001
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Human Immunodeficiency Virus (HIV) is the causative agent of Acquired Immune Deficiency Syndrome (AIDS). The C2-symmetric HIV-1 protease is one of the prime targets for chemotherapy in the treatment of the HIV infection. Inhibition of HIV-1 protease leads to immature and non-infectious viral particles. Design and synthesis of a number of C2-symmetrical C-terminal duplicated HIV-1 protease inhibitors and subsequent biological evaluation is presented in this thesis.A versatile three step synthetic route has been developed using a carbohydrate as an inexpensive chiral starting material thus allowing inhibitors with the desired stereochemistry to be obtained. By this efficient method a series of tailor-made P2/P2' modified inhibitors were synthesized, and these were evaluated on purified HIV-1 protease and in HIV-1 infected cell assays. Highly active HIV-1 protease inhibitors were identified among the tested compounds. Analyses of the X-ray crystal structures of two of the most active compounds, as complexes with the protease, guided the further design of P1/P1' elongated inhibitors. Substitutions in the para-position of the P1/P1' benzyl groups were promoted efficiently by microwave-irradiated of palladium-catalyzed reactions. Particular modifications in the P1/P1' region of the inhibitors resulted in a 40-fold increase of the anti-viral activity on HIV-1 infected cells. Furthermore, a fast, efficient, and general one-pot microwave enhanced synthesis protocol for transformations of organo-bromides to tetrazoles was developed and applied on the inhibitor scaffold. Attachment of linker molecules to the P1/P1' benzyl groups of one inhibitor was used to develop of sensitivity enhancer tools in surface plasmon resonance biosensor assays. These new assays enable the evaluation of low-molecular weight compounds as HIV-1 protease inhibitors.
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| 8. |
- Andersson, Agneta
(författare)
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Fatty Acid Composition in Skeletal Muscle : Influence of Physical Activity and Dietary Fat Quality
- 2001
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Insulin sensitivity is related to the fatty acid profile of skeletal muscle. The aim of this thesis was to investigate whether physical activity and dietary fat quality, independent of each other, influence the fatty acid composition of the skeletal muscle lipids. In an intervention study where middle-aged men were exercising for six weeks, and in a cross-sectional study comparing sedentary with endurance trained young men, it was demonstrated that the fatty acid composition of skeletal muscle lipids differed between physical active and inactive men. In brief, a lower proportion of palmitic acid (16:0) and total n-6 polyunsaturated fatty acids (PUFA) and a higher proportion of stearic (18:0) and oleic acid (18:1n-9) and total n-3 PUFA in the muscle phospholipids were associated with physical activity, despite similar fatty acid composition of the diet. In the second study, that included a larger training volume, differences in the fatty acid profile were also found in the skeletal muscle triglycerides. In contrast, after short-term supra-maximal exercise we found no significant changes in the proportion of the fatty acids in skeletal muscle. Furthermore, after a treatment period of three months, with diets with various dietary fat quality, the proportions of saturated fatty acids (14:0, 15:0 and 17:0) were higher and the proportion of 18:1 n-9 lower in subjects with a high intake of saturated fatty acids compared with subjects with a high intake of monounsaturated fatty acids. In addition subjects given n-3 supplementation had a higher proportion of total n-3 PUFA and lower n-6 PUFA in the skeletal muscle phospholipids than controls. Differences similar to those observed in the phospholipids were found in the triglycerides. In summary, these results suggest that regular aerobic physical activity and dietary fat quality influence the fatty acid composition of the skeletal muscle lipids, which may affect insulin sensitivity and glucose homeostasis.
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| 9. |
- Andersson, Anna
(författare)
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Surface Phenomena in Li-Ion Batteries
- 2001
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The formation of surface films on electrodes in contact with non-aqueous electrolytes in lithium-ion batteries has a vital impact on battery performance. A basic understanding of such films is essential to the development of next-generation power sources. The surface chemistry, morphology and thermal stability of two typical anode and cathode materials, graphite and LiNi0.8Co0.2O2, have here been evaluated by X-ray photoelectron spectroscopy (XPS), X-ray diffraction, scanning electron microscopy and differential scanning calorimetry, and placed in relation to the electrochemical performance of the electrodes. Chemical and morphological information on electrochemically formed graphite surface films has been obtained accurately by combining XPS measurements with Ar+ ion etching. An improved picture of the spatial organisation, including thickness determination of the surface film and characterisation of individual component species, has been established by a novel sputtering calibration procedure. The stability of the surface films has been shown to depend strongly on temperature and choice of lithium salt. Decomposition products from elevated-temperature storage in different electrolyte systems were identified and coupled to effects such as capacity loss and increase in electrode resistance. Different decomposition mechanisms are proposed for surface films formed in electrolytes containing LiBF4, LiPF6, LiN(SO2CF3)2 and LiCF3SO3 salts.Surface film formation due to electrolyte decomposition has been confirmed on LiNi0.8Co0.2O2 positive electrodes. An overall surface-layer increase with temperature has been identified and provides an explanation for the impedance increase the material experiences on elevated-temperature storage. Surface phenomena are clearly major factors to consider in selecting materials for practical Li-ion batteries.
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| 10. |
- Andersson, Eva
(författare)
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Från Sorgedalen till Glädjehöjden – omgivningens betydelse för socioekonomisk karriär
- 2001
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The aim of the study is to analyse the significance of surroundings for an individual's socio-economic career in the form of education, occupational status and income. Guided by a social theoretical perspective the study reveals places of good fortune and places of few opportunities.The approach uses two empirical data sets. The first is a register database with in-dividuals in the Swedish municipalities of Gävle, Jönköping and Västerås. A cluster analysis was conducted and forms the physical and socio-demographic context of the 248 areas. The survey cohort consists of individuals born 1970, who lived at least five years in the same area during their adolescence. The most important finding is that the socio-demographic and physical context of the residential area of adolescence affects the subsequent socio-economical career. The second data set includes data from an interview study carried out with residents in the three municipalities. Inter-viewees speak to contextual effects on their socio-economic career and emphasised the importance of surroundings, especially for children.More specifically, the quantitative multi-level analyses showed that the individ-ual’s socio-demographic context during 1985-89 was significantly associated with his/her education in 1995. The individuals who lived in dwellings built during the Million Programme era had fewer years of education than others did and lower chances of being employed. Favourable places for a socio-economic career are those dominated by middle-class families where contextual effects towards higher educa-tion are evident. The income of an individual though can not be clearly considered as effected from the context in the residential area.The political implications of the study should be considered together with the nu-merous area-based programs in Sweden directed to improve conditions such as de-gree of occupation, education and income. Further studies on contextual effects can help to guide allocation of resources to schools and education in certain residential areas.
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