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This thesis presents the findings from an ethnography of stem cell science based on fieldwork with researchers in two connected laboratories in Scotland and the United States. It explores stem cell scientists' complicated interactions with live stem cell cultures within national projects of translational regenerative medicine. This analysis both draws upon and contributes to the social studies of biomedicine, reproductive studies and science and technology studies. I examine how stem cell scientists, involved in an international research initiative, navigate the challenging landscapes of translational regenerative medicine and attempt to transform fragile live cell cultures into successful biotechnical, medical and economic products. By considering translational regenerative medicine as an effort to reformulate the relationship between biology and technology in terms of applicability and utility, I illuminate tensions between the specific practices of care that enable stem cell growth in vitro and the elusive goals of national projects of biotechnological innovation. A major focus of this study is the means by which scientists in the two laboratories manage the inherent uncertainties of both cell culture and translational science. By exploring how researchers react to unstable and unpredictable cellular behaviour in the laboratory, while also managing the expectations of government and external funding bodies, I provide a portrait of the complex sociality of contemporary bioscience. In addition to the international collaboration between the two laboratories, I explore scientists' interdisciplinary work with medical specialists and public engagement with stakeholders in regenerative medicine. In doing so, I pay attention to the ways in which scientists themselves deal with and reflect on the relational and interdependent nature of their endeavours. Drawing on twenty-two months of ethnographic fieldwork and fifty qualitative interviews, I show how stem cell scientists' new engagement practices also inform scientific work and the care of stem cells in the laboratory. In short, I argue that translation of science across different sites at once creates and depends on new social relations between stem cells, people and communities. After providing an overview of the literature, central questions and methodology that frame this thesis, I introduce the opportunities and challenges that translational regenerative medicine goals create for the care of stem cells in vitro. From there, I zoom out beyond the tissue culture flask to demonstrate how the necessity for science applicability creates new responsibilities for scientists to connect with stakeholders in regenerative medicine outside of the laboratory. I conclude that a consideration of scientists' ties and societal links is significant for an understanding of the connection between the biological and the technological.

Broadly speaking, the oxidation of volatile organic compounds (VOCs) in the atmosphere aids in the formation of (1) ozone and (2) secondary organic aerosol. Both of these products have air quality as well as health and climate impacts. Additionally, studying the oxidation of VOCs under pristine conditions, such as those found in rural forests, is crucial for our understanding of atmospheric chemistry under pre-industrial conditions. Given that many climate models use the pre-industrial era as a baseline for their simulations, it is imperative to understand atmospheric chemistry with little anthropogenic influence. Since formaldehyde (HCHO) is a ubiquitous oxidation product of VOCs, it is commonly used as a constraint in models to test our latest understanding of oxidation chemistry in the atmosphere. However, using HCHO as a tracer of oxidation chemistry, such as in a pristine forest, requires knowing the magnitude of its sources and sinks. This work analyzes the source and sink budget of HCHO in a pristine forest located near Pellston, Michigan, during the PROPHET-AMOS field campaign that took place in July 2016. The HCHO budget is approached in three ways. First, vertically-resolved gradients of HCHO were measured at the field site using an upgraded laser-induced fluorescence (LIF) instrument for measuring HCHO. Second, leaf cuvette measurements conducted in the laboratory on Northern red oak (Quercus rubra) and Leyland cypress (Cupressus x leylandii) saplings were performed to understand the bidirectional exchange of HCHO with foliage as well as quantify the HCHO yield from the heterogeneous conversion of isoprene hydroxy hydroperoxides (e.g., 1,2-ISOPOOH) depositing on leaves. Finally, a 1-D forest canopy model (FORCAsT) was updated with laboratory measurements and a modified version of the Reduced Caltech Isoprene Mechanism (RCIM) to simulate the HCHO budget on a photochemically-active day in the forest. Discrepancies between modeled and measured HCHO thus help to show gaps in our understanding of oxidative and transport processes within pristine forested environments.

Fish move up- and downstream within rivers throughout their lives to find suitable habitats. During downstream movements, they can incur severe or even lethal injuries when passing through hydropower plant (HPP) turbines or when they are entrained at other water intakes. Horizontal bar rack bypass systems (HBR-BSs) are a state-of-the-art technology to protect and guide downstream moving fish through a safe corridor around water intakes. They are in operation at multiple HPPs for more than a decade, but technical knowledge about the velocity fields, the head losses, the fish guidance efficiency, and the clogging probability was so far missing. This doctoral thesis encompasses the state of knowledge of HBR-BSs and contributes with novel findings to this topic through hydraulic experiments and live fish tests. The velocity fields of HBR-BSs and hydraulic losses of horizontal bar racks (HBRs) were quantified for a wide parameter range. The fish guidance efficiency was assessed through live fish tests involving a diverse assemblage of riverine fish species, namely spirlin (Alburnoides bipunctatus), barbel (Barbus barbus), nase (Chondrostoma nasus), brown trout (Salmo trutta), Atlantic salmon parr (Salmo salar), and European eel (Anguilla anguilla). Systematic experiments with leaves of different tree species were carried out to determine the clogging probability at HBRs. The main findings of the present thesis include a detailed analysis of the effect of different parameters on the velocity fields up- and downstream of HBRs. Equations were proposed to predict the head losses at HBRs, which can be applied for a wide parameter range, including rectangular and foil-shaped bars, bottom and top overlays, and different HPP layouts. By applying foil-shaped instead of rectangular bars, the losses were reduced by more than 40%, depending on the rack configuration. The fish swimming behavior was analyzed in detail and equations were proposed to estimate the protection and guidance efficiency of HBR-BSs as a function of the clear bar spacing and the fish dimensions. The fish protection efficiency varied between the factors fish species, size, and clear bar spacing of the HBR. While the laboratory HBR-BS with a clear bar spacing of 20mm offered hardly any protection for juvenile nase, the average protection efficiency exceeded 90% for spirlin and European eel. The behavioral avoidance effect strongly increased with the application of a low-voltage electric field to the HBR-BS. High protection efficiencies were achieved for spirlin and eel, but their behavior strongly depended on their orientation in the electric field and spirlin often refused to enter the bypass. The probability that a leaf clogged at any bar of an HBR decreased linearly for larger clear bar spacings, while the probability of clogging over multiple bars decayed exponentially. The present work provides technical knowledge to design HBR-BSs, thereby accounting for fish protection, cost-efficiency, and sustainable operation. The weighting of these aspects has to be defined by involving all stakeholders. The findings of the present study contribute to a better understanding of the hydraulic processes and the fish behavior at HBR-BSs, but they cannot replace extensive monitoring campaigns at prototype sites, which are necessary to verify functional efficiency.

The projected increase in distributed power generation (DG) has given rise to the concerns on the air quality impact of small power plants located in urban areas. In order to estimate this impact, there is a need for a model that can treat plume rise and dispersion of a buoyant release in an inhomogeneous urban boundary layer whose structure is governed by complex surface characteristics. Such a model requires three essential ingredients: 1) a realistic treatment of the interaction between the highly turbulent urban canopy layer and the turbulent plume spread, 2) a plume rise model that can accounts for the flow modifications caused by buildings, and 3) an appropriate estimate of the height of the nocturnal urban boundary layer. Comprehensive laboratory and field studies were conducted to investigate each of these elements separately. Ground level concentrations (GLC) associated with a modeled DG were measured inside the water channel under different surrounding building geometries. Results from these measurements indicated that surrounding buildings induce vigorous vertical mixing which increase the near source GLC. Further investigations focused on the plume rise from these sources. The results from plume rise measurements suggested that plume exiting the DG stack can be significantly impacted by the flows induced by surrounding buildings. In addition to dispersion and plume rise measurements, a field study was conducted in Riverside, CA and the structure of the nocturnal urban boundary layer was investigated over three different nights. Results from these measurements helped us to develop a semi-empirical model that can predict the height of the stable boundary layer. Although we were able to reasonably understand and develop models to predict the micro-meteorology as well as plume rise and spread; we concluded that simple Gaussian dispersion models have limited performance in predicting the concentrations associated with urban sources due to the substantial complexity involved with the urban dispersion process.