Coming dissertations at Uppsala university
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Role of β-myrcene in attenuation of neurodegeneration, renal malfunction, and Inflammatory bowel disease in the Adrenalectomized Rat model
Link: http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-537487
Glucocorticoids (GCs) are secreted by the adrenal glands in response to signals from the hypothalamus and pituitary gland through the hypothalamic–pituitary–adrenal axis. Physiological GCs are important regulators of immunity, energy metabolism, oxidative stress response, and cellular homeostasis.
Adrenalectomy (ADX) results in the loss of hippocampal neurons including the dentate gyrus, and cornu ammonis. Pathways implicated in neurodegeneration include inflammation, upregulation of microglia and astrocytes, oxidative stress, downregulation of autophagy, disruption of cellular homeostasis, and increased apoptosis. The autophagy lysosomal pathway plays a pivotal role in the degradation of damaged organelles and retrieval of proteins essential for the cell cycle and intracellular homeostasis. Metabolism and homeostasis in the hippocampal neurons are mediated by the mammalian target of rapamycin through the autophagy lysosomal pathway. Myrcene was evaluated to mitigate inflammation and oxidative stress and reinstate metabolism and cellular homeostasis. Myrcene attenuated inflammation, deactivated glial cells and astrocytes, relieved oxidative stress, reinstated autophagy, promoted hippocampal neuronal growth, ensured homeostasis, and prevented apoptosis in adrenalectomized rats.
ADX-mediated GC depletion mediated renal inflammation, induced oxidative stress, and exacerbated renal injury, leading to functional impairment and increased mortality in inflammatory bowel disease (IBD). Meanwhile, myrcene abrogated the inflammatory plethora and inhibited reactive oxygen species (ROS), ultimately preventing renal injury and reducing mortality in adrenalectomized rats with IBD. Furthermore, in ADX-induced inflammation and oxidative stress, myrcene attenuated renal inflammation and inhibited ROS. ADX promotes the recruitment of macrophages in the kidney, which exacerbates inflammation and oxidative stress, ultimately leading to the impairment of renal function. Myrcene attenuated renal inflammation and oxidative stress, reinstating the renal function, in ADX-treated rats.
Overall, myrcene prevents neurodegeneration, improves renal function, and mitigates IBD complications, exhibiting potency in alleviating neuronal and renal inflammation and oxidative stress.
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Technology, Nonstandard Jobs, Occupations, and Firm Performance
Link: http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-537155
Essay I: This study is the first to examine the relationship between ICT adoption and nonstandard employment using country-industry-level data on ICT adoption combined with individual-level contract type data for 15 European countries. Using a multi fixed-effect model, I find that workers in industries at the 90th percentile of ICT capital per worker are about 3 percentage points less likely to hold temporary contracts and 5 percentage points more likely to hold part-time contracts compared to those in the 10th percentile. Both effects are driven by changes in non-routine occupations. The decreased incidence of temporary employment is mainly attributed to changes among involuntary temporary workers, while the increased incidence of part-time employment is most pronounced among those working part time for family, personal reasons, or care responsibilities. Overall, ICT adoption appears to improve contractual conditions by reducing the incidence of involuntary temporary employment and expanding opportunities for voluntary part-time work.
Essay II: This paper examines the impact of technology on temporary and part-time jobs using the case of surgical robots. By exploiting the staggered adoption of surgical robots across Swedish hospitals, I study the causal effects on nonstandard nursing jobs through a staggered difference-in-differences strategy. Linking hospital surgery data with job advertisements, I find that robot adoption reduces part-time job incidence among operating room nurses, which may be due to hospitals’ investment in training programs for this advanced robotic technology. Conversely, the incidence of temporary jobs increases post-adoption, which may be attributed to a screening mechanism: as the new skills required by robotic surgery are difficult to assess beforehand, hospitals use temporary contracts to evaluate applicants' suitability.
Essay III: (with Oskar Nordström Skans): We analyze the firm-level consequences of automation when firms have heterogeneous factor shares. Innovations that lower the cost of replacing specific tasks within firms should benefit firms with high employment shares in the associated occupations. Conversely, falling costs of machine services that complement other types of labor at the firm level should benefit firms with lower factor shares in declining occupations. While these two scenarios may have similar impacts on aggregate labor demand, they predict opposite outcomes at the firm level. Using Swedish register data, we correlate firms' initial occupational employment shares with subsequent growth in firm sales. We find a clear positive association between initial labor intensity in declining occupations and future market share growth, suggesting that tasks were primarily replaced through substitution within firms.
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Exploring the nucleon electromagnetic form factors with non-perturbative methods
Link: http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-537441
The thesis studies the nucleon electromagnetic form factors at low energies, which is crucial for understanding the internal structure of nucleons and their excited states. Yet the non-perturbative nature of Quantum Chromodynamics (QCD) poses significant challenges on the theory side.
It's been known that the effective field theory of QCD—chiral perturbation theory (ChPT)— cannot describe the nucleon elastic form factors well since it does not contain the vector mesons explicitly. To tackle the challenge, this thesis introduces a model-independent formalism that integrates ChPT with non-perturbative dispersion theory, termed Dispersively Modified Chiral Perturbation Theory. The new formalism can incorporate the ρ meson model independently while still maintaining the chiral power counting. This novel approach allows for the investigation of both the Q2 dependence and quark mass dependence of nucleon form factors, ensuring consistency with chiral symmetry while remaining systematically improvable. It is also demonstrated in the thesis that the new formalism outperforms the plain ChPT when comparing both to lattice QCD calculations.
The nucleon transition form factors (TFFs) are also poorly understood at low energies due to the meson cloud effects. In the thesis, a dispersive approach is proposed to explore the transition form factors of the nucleon to its excited state N*(1520) with JP=3/2—. It is the first time a model-independent calculation is made for N*(1520). The results show good agreement with the existing data on TFFs in the space-like region. Based on the dispersive formalism, predictions for the time-like TFFs are made for future experiments. This work advances the model-independent understanding of nucleon structure and the strong force at low energies.