Coming theses from other universities
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Garnishing the smorgasbord of pharmacometric methods
Link: http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-518178
The smorgasbord of methods that we use within the field of pharmacometrics has developed steadily over several decades and is now a well-laid-out buffet. This thesis adds some garnish to the table in the form of small improvements to the handling of certain problems.
The first problem tackled by the thesis was the challenge of saddle points and local non-identifiability when estimating pharmacometric model parameters. Substituting the common method of randomly perturbing the initial parameter estimates with one saddle-reset step enhances the accuracy of maximum likelihood estimates by overcoming saddle points parameter values, a common issue in nonlinear mixed-effects models. This algorithm, as implemented in the NONMEM software, was applied to various identifiable and nonidentifiable pharmacometric models, showing improved performance over traditional methods.
Part of the thesis was dedicated to the development of a paediatric pharmacokinetic model for ethionamide, a drug used in treating multidrug-resistant tuberculosis. The resulting model was then used to simulate drug exposure under different dosing regimens, a new dosing regimen for children was proposed. The developed model, and therefore the proposed paediatric dosing regimen, considers factors like maturation of pharmacokinetic pathways and, administration by nasogastric tube, and concurrent rifampicin treatment. The regimen, with some modifications, was adopted in the 2022 update to the World Health Organization operational handbook on tuberculosis.
Finally, the thesis explored novel model-integrated evidence (MIE) approaches for bioequivalence (BE) determination. Such methods could offer more robust alternatives to standard BE approached using non-compartmental analysis (NCA). Model-based methods have been shown to be advantageous in sparse data situations, such as is found in studies of ophthalmic formulations, but have suffered from inflated type I error rates. MIE BE approaches using a single model or using model averaging were presented and shown to control type I error at the nominal level while demonstrating increased power in bioequivalence determination.
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Daily Experiences and Perceived Quality of Care for Patients with Liver Cirrhosis
Link: http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-517092
Aim and methods: This thesis aimed to study patients’ experiences with illness in their day-to-day lives and their perceived quality of care before and after implementing a 24-month adjunctive registered nurse-based outpatient intervention in liver cirrhosis. Qualitative data was used to explore patient perspectives on day-to-day life and healthcare experiences related to liver cirrhosis. The patient-perceived quality of care following the adjunctive registered nurse-based outpatient care was studied in a pragmatic, randomised controlled multicentre study, preceded by a study protocol.
Results: Liver cirrhosis led to physical symptoms sometimes appearing rapidly. Fatigue, fear and social stigma affected daily life, resulting in cancelled activities and creating an unpredictable daily life situation. Patients with liver cirrhosis lacked adequate support to learn about the disease and manage it. They sought a trustworthy relationship with healthcare providers. When this was lacking, they felt neglected. After 12 months, the adjunctive registered nurse-based outpatient care revealed an improvement in patient-perceived quality of care. Enhancements were observed in 7 out of 22 questionnaire items regarding: patient participation, access to outpatient care, and feeling understood. However, these improvements were not sustained after 24 months.
Conclusions: Fluctuating liver cirrhosis symptoms and constant worry significantly impact patients’ daily lives. Patients expressed a wish to be more involved in their healthcare and support in understanding and managing their illness. Structured registered nurse-based outpatient care for liver cirrhosis could complement physician-based care to meet patient desires for a more person-centred approach, continuity and care coordination.
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Stimuli-Responsive Materials Derived from Cellulose Nanofibrils : Synthesis, characterization, and performance evaluation
Link: http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-224538
This thesis presents a comprehensive study on stimuli-responsive materials derived from cellulose nanofibrils (CNFs), focusing on their synthesis, characterization, and performance evaluation in various applications. Renowned for their biodegradability, renewability, and robust mechanical properties, CNFs are explored in three primary contexts: moisture-responsive actuators, voltage-responsive actuators, and CO2-responsive sensors.
The unique properties of CNFs, such as high tensile strength and surface area, are leveraged to achieve effective motion in response to moisture exposure. Specifically, CNFs are utilized to create bilayer, torsional, and tensile actuators. These actuators exhibit controllable and dynamic responses, making them suitable for applications in soft robotics and wearable technology.
In the realm of voltage-responsive actuators, this study investigates the impact of various electrolytes and counteranions on positively charged CNFs. It uncovers the critical role of electrolyte choice, ion migration and the plasticization effect within the CNFs matrix, resulting in volumetric expansion, which is pivotal to the actuation mechanism. These insights pave the way for CNFs applications requiring precise control of motion and flexibility in shape, such as in soft robotics.
The third area of application involves the development of a capacitive CO2 sensor using CNFs-based foams functionalized with primary amines to enhance CO2 capture through chemisorption. This functionalization turns the CNFs-based foam into an efficient dielectric layer (DE) for sensor applications. The addition of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) to the DE further expands the scope of sensor's capacitance change in response to CO2 exposure, underscoring its potential in environmental monitoring and CO2 detection.
Overall, this thesis emphasizes the versatility and adaptability of CNFs as a sustainable biomaterial for developing stimuli-responsive devices. The insights gained from studying CNFs in these varied applications contribute significantly to materials science and open new avenues for research in sustainable, bio-based materials.