Thiamine, or vitamin B1, is an essential micronutrient required for several metabolic processes in living cells. Except for thiamine producers, all organisms rely on dietary intake and insufficient supply can lead to deficiency. Since the 1970s, thiamine deficiency outbreaks have been episodically reported across the Northern Hemisphere, particularly affecting high trophic-level taxa, such as seabirds and top predator fish. Salmonids are especially vulnerable to this deficiency which causes high mortality among offspring. Despite extensive research and several hypotheses proposed, a single underlying cause behind the onset of this deficiency remains unidentified.

This thesis aims to provide a comprehensive understanding of thiamine status of Atlantic salmon (Salmo salar) populations across systems with (Baltic Sea) and without (Lake Vänern, North Atlantic Ocean) documented thiamine deficiency events. It explores thiamine dynamics throughout the adult life cycle and potential influencing factors, including diet, fitness variables, and gut microbiota diversity. Results of these analyses were used in a life-history theoretical model for optimal thiamine allocation between tissues.

Lake Vänern population exhibited the highest thiamine status, followed by North Atlantic and Baltic Sea populations. These differences might reflect different thiamine availability and diet due to different feeding grounds. However, thiamine status did not correlate with salmon fatty acid profiles, as previously proposed in literature, indicating that other factors might modulate thiamine concentrations. Interestingly, thiamine generally decreased as salmon approached spawning in both Baltic and North Atlantic populations. This reduction, as shown by the data and modelling with and without starvation, was likely a natural consequence of fasting rather than to be related to thiamine deficiency within the system. Moreover, changes in the salmon fatty acid profiles throughout their lifecycle were consistent for both low-thiamine populations (Baltic Sea) and intermediate-thiamine populations (North Atlantic), suggesting that these changes might not be involved in thiamine deficiency development. The gut microbiota analysis revealed that their composition varied across the studied systems, but microbiota species diversity showed little to no relationship to thiamine concentrations. However, thiamine-synthesizing microbial taxa tended to be more prevalent in salmon populations with high and intermediate thiamine status, suggesting a potential role in positively modulating the host’s thiamine status.

This research provides novel insights into the thiamine dynamics of Atlantic salmon, highlighting the complexity of factors influencing the thiamine status.

As soon as blood leaves the human body, stress to the host´s protective cellular and protein cascades begin. My thesis focuses on the immune system, specifically the complement system and platelets, primarily known for their hemostatic properties but also play a role in immune responses. The core of this thesis is the interaction between the complement system and platelets in platelet concentrates destined for transfusion. Storing blood products, particularly platelet concentrates, presents challenges, including the development of platelet storage lesions. These lesions involve a series of biochemical, structural, and functional changes from when platelets are collected to when they are transfused, potentially leading to impaired platelet function and adverse transfusion reactions. For inventory management, the oldest platelet concentrates are typically used first for transfusion. Understanding the interplay between the complement system and platelets during storage is crucial for improving the quality of platelet concentrates for selecting optimal concentrates based on the indication. This thesis includes several exploratory studies: one examining the complement system and platelet function over storage time, another investigating the impact of complement inhibition with the aim to reduce platelet storage lesions, and a third exploring the ability of platelets to release mediators that can modulate an immune response when supplemented to thrombocytopenic blood. Additionally, one study examines the impact of blood collection tube composition on complement functional and activation analysis. I found that increased storage time was associated with increased complement activation, increased platelet activation and attenuated platelet function. However, there was no causal relationship between complement and platelet activation since complement inhibition did not alter platelet activation or function. Further, I found that platelets release mediators that could modulate an inflammatory reaction, but the storage time had only minor effect on the immunomodulatory effect. Last, I found that the composition of blood collection tubes significantly affected complement activation. While these findings may not immediately benefit patients, they provide new insights into platelet concentrates, highlighting the role of the complement system. Further research is needed to to understand the interaction between these components fully.

This doctoral thesis examines the challenges and potential improvements in managing archaeological projects related to the Sámi people in Sweden. The focus is on aligning practices of contract archaeology with national and international policies for managing Indigenous cultural heritage. The research identifies five key challenges in Swedish archaeology: defining Sámi heritage sites, determining responsibility for relevant expertise, managing Sámi-related information, establishing processes of contract archaeology acceptable to all stakeholders, and deciding whether Sámi and "Swedish" heritage should be managed together or separately. The study compares the approach in Sweden with practices in Norway and British Columbia, Canada, to explore potential solutions. Different systems for cultural heritage management are analysed alongside interviews with archaeologists, Indigenous community members, officials, and other stakeholders, to map success factors and pitfalls of Indigenous cultural heritage management. The study highlights the slow implementation of the United Nations Declaration on the Rights of Indigenous Peoples (UNDRIP) in Sweden and the lack of legislation ensuring Sámi involvement in archaeological projects. The research suggests that addressing these challenges will require re-evaluating current practices, including developing clearer guidelines for managing Sámi heritage sites, improving collaboration between archaeologists and Sámi communities, finding ways to include intangible aspects of cultural heritage within cultural heritage management, and potentially delegating more authority in cultural heritage management to the Sámi Parliament. The thesis concludes by proposing strategies to better align Swedish contract archaeology with national and international policies on Indigenous cultural heritage, emphasizing the need for a balanced approach that respects Indigenous rights while addressing concerns in archaeological practice. These recommendations aim to ensure that Sámi cultural heritage is managed respectfully, acknowledging its unique history and perspectives, while facilitating effective collaboration among all stakeholders involved in archaeological projects.