UvA-DARE
Not a member yet
74486 research outputs found
Sort by
Ferrocene-based light-responsive carbon nanohoops
No full textThis thesis investigates the synthesis,structural characteristics, and photochemical behavior of cycloparaphenylenes(CPPs), with a focus on ferrocene-containing nanohoops (Fc[n]CPPs). Aninitial section examines an alternative protecting-group strategy for accessingprecursors of highly strained nanohoops, showing that sterically demandingsilyl groups such as tert-butyldimethylsilyl (TBDMS) offer robust andselective reactivity under mild conditions. The central part of this workdescribes the preparation and characterization of Fc[n]CPPs (n =6–8). The most strained member, Fc[6]CPP, exhibits exceptional photochemicalFe²⁺ uncaging under visible-light irradiation inthe presence of 1,10-phenanthroline, forming [Fe(phen)₃]²⁺ in high yield, including in aqueous media. Quantum-yield measurementsreveal a thousand-fold enhancement in reactivity relative to unstrainedferrocene, consistent with rapid nucleophilic interception of the nanohoop’striplet excited state. Furthermore, a comparative analysis of spectroscopic,electrochemical, and computational properties of Fc[n]CPPs (n =6–8) shows that efficient Fe–cyclopentadienyl (Fe–Cp) dissociation is retainedeven in less distorted systems. These data suggest that kinetic factors inducedby strain, rather than metallocene distortion alone, govern reactivity acrossthe series. Synthetic efforts toward the highly strained Fc[5]CPP successfully yieldedthe corresponding pro-aromatic precursor. Although final aromatization remainschallenging, the target nanohoop was observed for the first time. Finally, thesynthesis of ansa-bridged ferrocene nanohoops (a-Fc[6]CPP and a-Fc[8]CPP)is reported. These enantiopure nanoscrolls exhibit up to 20-fold enhancedvisible-light-induced Fe²⁺ uncaging, underscoring the stronginfluence of a conformational lock on metallocene photoreactivity andhighlighting the broader potential of CPP strain engineering for controlledphotoactivation.</p
Navigating contestation across business and civil society contexts:Stakeholder perspectives on sustainability
No full textFeeling watched:Understanding triggers of and responses to perceived surveillance in digital technologies
No full textAs digital technologies permeate daily life, individuals are continuously subject to the collection, processing, and storage of their personal data—a phenomenon known as dataveillance. Experiencing dataveillance practices triggers perceived surveillance: the feeling of being watched, listened to, or having one’s data recorded. This dissertation investigates perceived surveillance by examining individuals’ beliefs about dataveillance, the triggers and consequences of perceived surveillance, and the related individual and contextual factors.Across four empirical studies using qualitative interview, survey, and experimental methods in the Netherlands and the United Kingdom, the dissertation maps people’s folk theories of dataveillance, identifying a dominant belief that companies “do everything to collect data for money,” largely shaped by experiences with data-driven advertising. Although individuals acknowledge certain benefits of dataveillance, they also perceive power asymmetries, ethical and privacy risks, and feelings of violation and creepiness. Perceived surveillance intensifies when people encounter accurate algorithmic profiling or advertising that uses sensitive or extensive types of personal data. These triggers not only increase privacy protection intentions but may also foster privacy cynicism. Moreover, perceived surveillance harms attitudes toward advertisements, brands, and platforms involved in data-driven advertising practices. The level of perceived surveillance further varies across individuals (e.g., by age, education, privacy concerns, and conspiracy mentality) and technological contexts (e.g., social media vs. smart home devices).Overall, the dissertation advances understanding of how people experience dataveillance and highlights the need for more responsible data practices and regulatory protection to mitigate perceived surveillance and its negative consequences
From blood to biomarker:Exploring extracellular vesicles for stroke diagnosis
No full textTo minimize irreversible brain injury, fast identification and classification of patients presenting with stroke symptoms is essential. Current diagnosis depends on clinical assessment and CT scans, which are time-consuming, especially when patients need to be transferred to specialized stroke centers. A blood-based test that can be used in pre-hospital settings may accelerate diagnosis and improve patient outcomes. In this thesis, we investigated whether analysis of extracellular vesicles (EVs), small membrane-enclosed particles released by cells into blood and containing information about their cells of origin, offers potential biomarkers.First, we established a clinically applicable blood collection protocol that preserves the in vivo concentrations of blood EVs. Furthermore, we developed a practical approach to enable accurate EV concentration measurements by flow cytometry. Secondly, a biobank was established containing plasma samples from patients presenting with acute stroke symptoms. Analysis of a subset of these samples showed that concentrations of leukocyte-derived EVs are reduced in patients with ischemic stroke compared to all other patients presenting with stroke symptoms. Combining leukocyte-EV concentration with diastolic blood pressure further improved identification of ischemic stroke.Overall, this thesis investigated the potential diagnostic potential of measuring blood EVs in an acute clinical setting. By improving the reproducibility of EV research and indicates that EVs hold potential as biomarkers for acute stroke diagnosis. These findings may support the development of an EV-based point-of-care test, enabling earlier recognition and treatment of ischemic stroke
Psychopathology and violent extremism:The need for primary data and assessment of countering violent extremism (CVE) policies
No full textThis dissertation aims to contribute to our knowledge on the prevalence and relevance of psychopathology in violent extremist samples. It also adds empirical research on whether gender and psychopathology correlate to higher levels of violent extremism in the case of radicalising individuals. The latter information is incorporated in research on Countering Violent Extremism (CVE) policies to better understand challenges concerning psychopathology. As a result, this work contributes to a more balanced approach to the goal of lowering the chances of mentally ill persons committing violent extremist actions without harming and stigmatising the vast majority of mentally ill non-violent individuals (with extremist ideas). The findings in this dissertation show that psychopathology cannot be used as a predictor for violent extremism in the general population. In very rare cases in the general population, mental disorders could be relevant for highly individualised pathways which, combined with other factors, may ultimately culminate in violent extremist activity. However, once mental disorders are present, their roles may vary or be irrelevant. Additionally, although individualised gender-responsive approaches seem needed, no evidence is found that psychopathological profiles of radicalising women differ from their male counterparts. Finally, this dissertation displays how heterogeneous psychopathological roles could complicate the CVE-assessment of (potential) mentally ill violent extremists. This complexity runs through practitioners’ challenges in CVE about case-inclusion, case-management and case-outflow. Some Dutch practitioners, for instance, express concerns on whether they can ethically include severely mentally ill individuals in CVE-programmes. These conclusions act as springboards for renewed consultation within CVE-approaches and research agendas
Decoding the control of food intake:Insights from the habenula and hypothalamus
No full textThis thesis focused on the habenula and hypothalamus, two brain regions important for reward in general and food intake specifically, and their role in regulating (palatable) food intake. We first described a free-choice high-fat high-sugar diet (fcHFHSD) commonly used in our laboratory as a tool to gain mechanistic insights into the relevant brain circuits in the development of obesity. Next, we studied two populations of lateral hypothalamic (LH) neurons, the GABAergic and glutamatergic neurons, and their responses to sucrose drinking and how this was affected by the consumption of a fcHFHSD. Next, we focussed on the (lateral) habenula (LHb) and described that blocking all glutamatergic input to the LHb did not acutely affect palatable feeding, but had a more slow, modulatory effect. This could be driven by specific inputs to the LHb, of which we reported one projection from the central amygdala (CeA) dopamine receptor 1 (Drd1) expressing neurons. When chemogenetically manipulated, this specific CeADrd1+ connection did alter feeding behavior in a satiety state-dependent manner. Finally, to add translational knowledge, we used functional magnetic resonance imaging (fMRI) to study the resting state functional connectivity (rsFC) of the habenula in humans. We reported an interaction effect between BMI and hemoglobin A1c (HbA1c) for the habenula-ventral tegmental area (VTA) connection’s rsFC, suggesting an additional role for the habenula in glucose regulation. In conclusion, in this thesis, we described experiments that contributed to our knowledge of the habenula and hypothalamus and their control over food intake in the context of obesity development
The human cost of development:Situating development-induced displacement in international human rights law
No full textDevelopment-induced displacement (DID)—a phenomenon where people are involuntarily moved from their homes or residences to make room for development projects—is one of the prominent causes of internal displacement affecting millions of people every year. DID can be caused by a range of small and large-scale development projects, such as the construction of dams, urban (re)development projects, and extraction of natural resources. While these development projects have significant economic potential, the involuntary displacement they often cause comes with a plethora of risks and consequences including, inter alia, loss of land, a decrease of income sources, lack of access to public services, and disruption of culture and way of life. These adverse consequences further interfere with and potentially violate a range of human rights, such as the right to housing, the right to property, the right to work, and the right to education. Moreover, DID and its adverse consequences often hit the hardest vulnerable and marginalized groups potentially perpetuating existing vulnerabilities and inequalities. Against this background, the current study seeks to situate DID and its adverse consequences in international human rights law. Using the human rights-based approach as a theoretical framework, it seeks to (re)frame the adverse consequences of DID as human rights issues and explore rights-based solutions to address these issues. The study will identify the pertinent human rights norms and assess their application in the context of DID. In doing so, it seeks to explore the human rights safeguards that need to be provided for people(s) affected by DID and the corresponding obligations of states. Overall, the objectives of this research are twofold, i.e. map out the existing international human rights law norms that apply to DID and assess the adequacy of these norms in addressing the adverse consequences and the salient features of DID
Acute hamstring injury:Understanding return to play, reinjury and injury prevention strategies
No full textAcute hamstring injuries represent one of the most prevalent sports-related injuries with a high reinjury rate. However, the scientific knowledge on specific topics related to return to play, reinjury, and injury prevention strategies remains limited. This thesis aims to enhance the comprehensive understanding of acute hamstring injuries by addressing these three key areas. The first aim was to focus on the return to play prognosis and evaluate the role of MRI in the return to play decision-making process. The second aim focused on identifying reinjury predictors that are essential for reducing reinjury risk. The third aim investigated injury prevention strategies, with specific emphasis on overcoming implementation barriers in primary injury prevention and initiating trials for a hamstring secondary (reinjury) prevention program. For the first aim, five baseline clinical predictors and two baseline MRI predictors were identified as independent predictors of return to play, and complete normalization on 3.0-T MRI was found not to be expected prior to return-to-play decisions after hamstring injury. Second, two clinical findings, two MRI findings, and time to return to play were associated with increased reinjury risk. Third, our trial demonstrated no superior effect of low-volume Nordic hamstring exercises on performance improvement compared with the regular Nordic hamstring exercise program, indicating that identifying the minimum effective dose of low-volume Nordic hamstring exercise to overcome implementation barriers for injury prevention program remains a challenge.This thesis concludes by reflecting on the main findings of the research, comparing them with the existing literature, and providing recommendations for clinical practice and future research
Visa denied:Restrictive selectiveness within Schengen visa practices in West Africa
No full textToday, West Africa is among the regions experiencing the highest barriers to international travel. This particularly holds for travel to the European Union: in recent years, Schengen visa procedures experienced a significant shift, reinforcing restrictiveness over legal mobility from West Africa. Yet, restrictiveness alone does not explain current dynamics. The visa process itself reveals how states differentiate between applicants and select ‘desirable’ mobility through discretionary procedures. Despite the central role of visas in this selection process, little is known about everyday consular and application practices. This dissertation examines the politics of access to Schengen visa in West Africa, with a focus on Senegal, through a three-layered approach: first, visa as a leverage tool in the EU’s external dimension, where cooperation in migration control is bargained against temporary labour migration projects; second, the reorganisation of consular services through outsourcing and digitalisation of application procedures; third, the risk-assessment and profiling practices of consulates that create categories of ‘suspicious’ applicants.The study adopts a mixed-method design, combining interviews conducted with institutional authorities and civil society representatives in Senegal and with EU institutions, alongside the first analysis of disaggregated Schengen visa data covering the period 1999-2019. Findings reveal a system shaped by opacity, restrictive filtering practices, and the problematic role of digitalised and private application procedures. In fact, current consular profiling practices have considerably intensified selective outcomes. Eventually, this dissertation contributes to ongoing debates on Schengen visa policy as increasingly security-oriented and undermining equal access to legal pathways for West African citizens