Oratie uitgesproken door Prof. Dr. Suzan Verberne bij de aanvaarding van het ambt van hoogleraar Natural Language Processing aan de Universiteit Leiden op maandag 3 juni 2024_______________________... Show moreOratie uitgesproken door Prof. Dr. Suzan Verberne bij de aanvaarding van het ambt van hoogleraar Natural Language Processing aan de Universiteit Leiden op maandag 3 juni 2024____________________________________________________________Text also in English : Is the search engine of the future a chatbot? Show less
Oratie uitgesproken door Prof. dr. E.P.M. (Bart) Joosen bij de aanvaarding van het ambt van hoogleraar Financieel recht aan de Universiteit Leiden op vrijdag 24 mei 2024
Nicotinamide adenine dinucleotide (NAD+) is the substrate used for the introduction of the ubiquitous and highly dynamic PTM in which either one or multiple adenosine diphosphate ribose (ADPr)... Show moreNicotinamide adenine dinucleotide (NAD+) is the substrate used for the introduction of the ubiquitous and highly dynamic PTM in which either one or multiple adenosine diphosphate ribose (ADPr) moieties are covalently attached to a nucleophilic side chain of an specific amino acid in the target protein to regulate cellular pathways including adipogenesis, DNA damage repair and gene expression. A significant fraction of the nucleophilic amino acid functionalities, most recently histidine and tyrosine, have been identified as ADPr-acceptor sites. In this thesis, new methodologies have been developed to synthesize peptide fragments carrying an ADPr modification to investigate ADP-ribosylation on histidine. Show less
The research presented in this thesis concerns one of the most important questions in software engineering of our time: how can we make sure that software is free from memory safety bugs? Memory... Show moreThe research presented in this thesis concerns one of the most important questions in software engineering of our time: how can we make sure that software is free from memory safety bugs? Memory safety bugs are the major cause of common vulnerabilities and exposures, and their presence threatens the stability and security of our digital world. This question is so important that it has escalated to the highest level. In a recent White House press release (February 26, 2024), the National Cyber Director of the United States of America calls on the academic community to help solve this hard problem: “addressing [this challenge] is imperative to ensuring we can secure our digital ecosystem long-term and protect the security of our Nation.” The accompanying technical report advises on the use of memory safe programming languages, and prominently mentions formal methods as one way to achieve the highly desired freedom from bugs, including memory safety bugs.In this thesis, formal methods are studied that are used to analyze software for its correctness, where correctness means that software satisfies its specification and incorrectness means the presence of a bug. The focus is on separation logic, a formal method designed as a scalable technique in ensuring freedom from memory safety bugs. Nowadays, separation logic is a well-established field of research: it has been widely studied academically in the past twenty years, and is successfully applied on an industry-wide scale to ensure memory safety. For example, separation logic is the technique used to prove, with mathematical certainty, that memory safe programming languages (such as Rust and Go) indeed live up to the promise that “they offer a way to eliminate, not just mitigate, entire bug classes.”In two parts, this thesis presents important scientific contributions that fill a gap in the academic literature. The first part contains the missing completeness theorem for separation logic, that is on par with the fundamental result by Goedel for first-order logic. Completeness is important for any formal method as it shows that the formal method can be adequately used for demonstrating every validity. The second part finally introduces dynamic separation logic that gives an alternative way to analyze memory safety problems, such that now it is possible to prove elementary specifications without needing extra logical techniques. This is important because it ensures ‘backwards compatibility’ with automated reasoning techniques that are optimized for first-order logic. Show less
Visualizing the internal structure is a crucial step in acquiring knowledge about the origin, state, and composition of cultural heritage artifacts. Among the most powerful techniques for exposing... Show moreVisualizing the internal structure is a crucial step in acquiring knowledge about the origin, state, and composition of cultural heritage artifacts. Among the most powerful techniques for exposing the interior of cultural heritage objects is computed tomography (CT), a technique that computationally forms a 3D image using hundreds of radiographs acquired in a full circular range. The diversity in materials, shapes and sizes of cultural heritage objects poses a challenge for the broad application of this technique, since each scan needs to be tailored to the object. Moreover, the lack of affordable and versatile CT equipment in museums, combined with the challenge of transporting precious collection objects, currently keeps this technique out of reach for most cultural heritage applications. In this thesis, we explore how CT imaging can be further integrated in cultural heritage applications by 1) integrating expert feedback into the data acquisition process, 2) tailoring acquisition methods to obtain specific information, 3) developing a low-cost method to use in-house X-ray facilities for 3D CT imaging and 4) providing tools to interactively visualise and inspect the CT data. Show less
The use of opioid is increasing in the Netherlands, which is reflected in an increase in complications associated with the use, such as hospital admission and death due to opioid poisoning. In... Show moreThe use of opioid is increasing in the Netherlands, which is reflected in an increase in complications associated with the use, such as hospital admission and death due to opioid poisoning. In addition to these direct hazards of opioid use, patients also face the risk of unplanned ICU admission and all-cause mortality. Dependent on socio-demographic characteristics and co-morbidities the risk of theseoutcomes may vary, but is unique to the general population of the Netherlands when compared to other countries. Show less
Diacylglycerol lipases (DAGLα and DAGLβ) are responsible for the biosynthesis of the endocannabinoid 2-arachidonoylglycerol (2-AG) in the brain and peripheral tissues. Selective DAGLβ inhibitors... Show moreDiacylglycerol lipases (DAGLα and DAGLβ) are responsible for the biosynthesis of the endocannabinoid 2-arachidonoylglycerol (2-AG) in the brain and peripheral tissues. Selective DAGLβ inhibitors have been proposed as a potential treatment for inflammatory diseases with reduced potential for central nervous system (CNS) mediated side effects, but they are currently lacking. To develop DAGLβ selective inhibitors, a fluorescent biochemical assay was optimized and applied in a high-throughput screening (HTS) for DAGLβ. During the HTS, eight hits classified into four distinct chemotypes were identified. Subsequent structure-activity relationship (SAR) studies, focusing on hit 1 and its modifications, revealed a specific group as the modification hotspot crucial for achieving selectivity towards DAGLβ. Through an extensive SAR investigation, focusing on modifying this group, the first-in-class DAGLβ selective inhibitors, LEI-130 and LEI-131, were discovered. Following their discovery, LEI-130 and LEI-131 underwent comprehensive in vitro and in situ profiling studies. These investigations confirmed that LEI-130 and LEI-131 are selective and noncompetitive inhibitors of DAGLβ, effectively reducing inflammation. Show less
The endocannabinoid receptors CB1R and CB2R are involved in a plethora of processes, and consequently are involved in many pathological conditions. Their wide distribution makes the CBRs both an... Show moreThe endocannabinoid receptors CB1R and CB2R are involved in a plethora of processes, and consequently are involved in many pathological conditions. Their wide distribution makes the CBRs both an interesting therapeutic target and hard to study. Additional chemical tools are required to study and understand the function and mechanism of CB1R and CB2R. This thesis describes the development of several such tools to improve our insight in the (pathological) roles of the receptors in order to develop novel and improved therapeutics. First evaluation of three dimensional ligand-CB2R complexes made and analysed with Cryo-EM are described. Hotspots that potentially generate selectivity between CB1R and CB2R are evaluated with point-mutations in vitro. Consequently describes the development of the first tools, two-step bifunctional probes based on LEI-121 and LEI 102, is described. As two-step probes are not compatible with every assay, the toolbox is expanded with a one-step fluorescent probe. Briefly touching upon CB1R, ligands were designed with negatively charged phosphonium groups that are potentially selective for mtCB1R. Show less
Throughout the history of computer science, a major challenge has been how to assert that software is free of bugs and works as intended. Software bugs can lead to serious negative impacts on any... Show moreThroughout the history of computer science, a major challenge has been how to assert that software is free of bugs and works as intended. Software bugs can lead to serious negative impacts on any software system. Throughout the main body of the thesis, we implemented a series of studies on exploring ways to apply formal methods systematically for the verification of complex object-oriented libraries such as the Java Collection Framework. We start with specifying and verifying methods in the java.util.LinkedList class, but we encounter challenges with methods that take an interface type as a parameter. To address this, we proposed to use histories as method calls and returns to completely determine the concrete state of any implementation and thus can be seen as a way to reason about the interface. The executable history-based (EHB) approach embeds histories and attributes directly as Java objects. This approach could be seamlessly integrated in the KeY theorem prover itself. However, the EHB approach still has its limitations, particularly when it comes to reasoning about the heap and properties of user-defined attributes.To mitigate this, we introduce the logical history-based (LHB) approach, which models histories as an external abstract data type with functions. Building on the LHB approach, we have developed a history-based refinement theory for reasoning about hierarchy in object-oriented programs. Show less
Malaria continues to wreak havoc in tropical regions, due largely to the lack of an effective vaccine. Vaccine candidates based on whole parasites have shown promising results in malaria-naïve... Show moreMalaria continues to wreak havoc in tropical regions, due largely to the lack of an effective vaccine. Vaccine candidates based on whole parasites have shown promising results in malaria-naïve individuals, but their potency in malaria-exposed individuals is considerably lower. This dissertation described the development of a chemical strategy for boosting such parasites’ potency in pursuit of more efficacious malaria vaccines for use in endemic areas.Chapter 2 outlined the adaptation of a method for chemically modifying microbial cell surfaces.Chapter 3 showed the chemistry underlying this modification system to be stably compatible with in vivo usage.Chapter 4 demonstrated that when the chemical modification system was used to introduce immune-potentiating agents onto bacteria, better immune responses ensued.Chapter 5 tied it all together by using the chemical modification system to potentiate malaria parasites, and showed that doing so markedly improved immune responses in an in vivo immunization model.Chapter 6 summarized these findings in the context of malaria vaccine development and posited next steps forward. Show less
In this dissertation we investigate the emotional and psychiatric effects of glucocorticoids (e.g. cortisol, dexamethasone and prednisone). Glucocorticoids are widely used and their possible... Show moreIn this dissertation we investigate the emotional and psychiatric effects of glucocorticoids (e.g. cortisol, dexamethasone and prednisone). Glucocorticoids are widely used and their possible psychiatric side effects are well known. It is still unclear who is susceptible to side effects and what mechanism is behind this. In this thesis we try to better understand the underlying causes. For example, we use a relatively new static method in this research field, which can analyze changes over time better than the usual methods. In a study, we show that in depressed study participants, changes in certain affect items preceded changes in cortisol levels, while in control participants this was the other way around. Furthermore, we explore a hypothesis that may explain the mechanism of the psychiatric side effects of glucocorticoids. This mechanism is also used for a strategy to prevent the psychiatric side effects. The strategy is based on the fact that synthetic glucocorticoids are very similar to the body's own hormone cortisol, but their binding to the two cortisol receptor proteins and their effects may be different. By achieving a balanced activation of the two cortisol proteins when using glucocorticoids, the psychiatric side effects could possibly be prevented. In summary, this thesis provides further insight into the emotional and psychiatric side effects of glucocorticoids, but the search for a better understanding of the neuropsychiatric side effects remains a pressing concern, which will hopefully benefit patient care in the future. Show less
The lipids in the uppermost layer of the skin, the stratum corneum (SC), play an important role in the skin barrier function. The three main SC lipid classes are ceramides (CER), cholesterol and... Show moreThe lipids in the uppermost layer of the skin, the stratum corneum (SC), play an important role in the skin barrier function. The three main SC lipid classes are ceramides (CER), cholesterol and free fatty acids. In inflammatory skin diseases, such as atopic dermatitis and psoriasis, the SC lipid composition is altered compared to the healthy SC composition. The studies presented in this thesis focused on the effect of the CER subclass composition on the lipid organization, molecular arrangement and barrier function of the skin. First, the CER compositional changes were examined in the SC of seborrheic dermatitis patients, an inflammatory skin disease. A particular emphasis was paid to the ratio of two important CER subclasses, sphingosine CER (CER NS) and phytosphingosine CER (CER NP), and its correlation to the skin barrier. In the subsequent chapters lipid model systems with a simple CER subclass composition were used to study the influence of the CER NS: CER NP molar ratio on the barrier function and lipid organization. Show less
The dissertation investigates the role of lexical tone in spoken word recognition and production. In particular, it focuses on three groups of speakers: native speakers of Standard Chinese, bi... Show moreThe dissertation investigates the role of lexical tone in spoken word recognition and production. In particular, it focuses on three groups of speakers: native speakers of Standard Chinese, bi-dialectal speakers of Standard Chinese and Xi’an Mandarin, and bilingual speakers of Standard Chinese and English. Through a series of experiments employing the eye-tracking visual world paradigm and the picture-word interference paradigm, four key issues were explored: the role of lexical tone in Mandarin spoken word recognition; tonal interference in bi-dialectal spoken word recognition; the activation of lexical tone in bilingual spoken word production; and the influence of lexical tone on the bilingual mental lexicon. The findings of this dissertation not only showed how Mandarin listeners utilize tonal information during tone word recognition but also revealed dynamic tonal interaction between language systems. Overall, this dissertation contributes to a deeper understanding of lexical access by highlighting the significant role of lexical tone in both monolingual and bilingual contexts, shedding light on the intricate processes involved in spoken word recognition and production across languages. Show less
This thesis has studied several modalities how to increase the organ utilisation rate. The results in this thesis indicate that the acceptance of kidneys with acute kidney injury stage 1 or 2 will... Show moreThis thesis has studied several modalities how to increase the organ utilisation rate. The results in this thesis indicate that the acceptance of kidneys with acute kidney injury stage 1 or 2 will significantly contribute to the donor pool as AKI kidneys have comparable outcomes and should therefore not be discarded. Clinically relevant biomarkers such as cell-free unmethylated-INS DNA, FMN, GSN, IGFBP3 and IGF2R were identified or explored in the first part of this thesis and may, if analysed and/or validated thoroughly, contribute to a better assessment of organ viability supporting the justified decision whether to accept or decline the donor organ.The second part of this thesis describes different aspects of the organ preservation technique of abdominal normothermic regional perfusion (aNRP). This relatively new machine perfusion technique has been shown to be feasible and safe, however, consensus regarding assessment parameters during perfusion, protocols and outcome measurements is still lacking. Despite of an inspiring surgical enthusiasm and keeninterest to accept this modality as a new standard, a randomised clinical trial is still required and entirely ethically justifiable in order to scientifically demonstrate superiority of this method for each individual abdominal organ comparing it to other successful (ex-situ) preservation and perfusion strategies. If aNRP can be shown to obtain better post transplantation outcomes whilst increasing organ utilisation, it may be the least complex and most cost-effective strategy in organ preservation. On the other hand, aNRP will only be used in DCD donors. As such, uncertainty regarding the quality of higher risk organs from DBD donors will still be evaluated ex-situ during cold and/or warm machine perfusion with the potential to repair or even regenerate injured organs and making them ‘transplantable’ again. Show less
Demand for palliative care is expected to rise due to an ageing population, an increase in chronic diseases, and multimorbidity. Currently, many countries, including the Netherlands, are dealing... Show moreDemand for palliative care is expected to rise due to an ageing population, an increase in chronic diseases, and multimorbidity. Currently, many countries, including the Netherlands, are dealing with a high demand and shortages of professionals in the healthcare sector. Because of the different nature of providing palliative care compared to curative care and the expected increase in demand for palliative care, the focus of this thesis is to gain insight into the emotional impact of providing palliative care on healthcare professionals.This thesis highlights the emotional stressors healthcare professionals encounter in providing palliative care. Building personal relationships with patients bring both rewarding and emotionally experiences, especially when patients are dying. Among palliative care professionals higher burnout rates were found in general settings than in specialised palliative care settings, possibly due to insufficient training and attention to the emotional impact of providing palliative care in the former.Education and group meetings are seen as crucial for raising awareness and reducing stress. This thesis emphasizes the need for team and organisational support to adequately address the wellbeing of healthcare professionals in this growing field. It requires shared responsibility and action from organisations, teams and healthcare professionals to care about the care for healthcare professionals providing palliative care. Show less
During the Cold War, the Dutch Army Medical Service (MGD) promoted the health and operational readiness of the Royal Netherlands Army. Medical war preparations were an integral part of this. The... Show moreDuring the Cold War, the Dutch Army Medical Service (MGD) promoted the health and operational readiness of the Royal Netherlands Army. Medical war preparations were an integral part of this. The evacuation, treatment and nursing of sick and wounded soldiers in wartime required the formulation of procedures and doctrines as well as an extensive organization, complete with supplies and equipment, trained personnel and mobilization plans. However, these activities were shrouded in uncertainty as the prospect of biological, chemical or even nuclear warfare called into question all casualty estimations based on previous conflicts.The central question in this dissertation is how the MGD dealt with the nuclear threat perception and how military-medical war preparations were influenced by it. Against the backdrop of the ominous prospects of future warfare, military physicians tried to legitimize their war preparations and make sense of them. This mechanism is made clear using the concept of sociotechnical imaginaries: constructed optimistic images of the future that are based on the collective belief in scientific and technological progress. This study shows that the MGD maintained an optimistic outlook from the beginning through the end of the Cold War, but the reasoning that supported this viewpoint evolved over time. Show less
Emotions significantly influence our perceptions and interactions with the environment, yet the impact of our emotional states on judging and responding to others remains underexplored. In this... Show moreEmotions significantly influence our perceptions and interactions with the environment, yet the impact of our emotional states on judging and responding to others remains underexplored. In this thesis, I examined how (romantic) attraction influences our attention (Part I), how we judge others’ intentions (Part II), and whether mimicking another facilitates bond formation (Part III). In two empirical chapters, I demonstrate that people have a strong attentional bias towards visual attractiveness and a tendency to indicate interest in establishing a romantic connection to attractive others. In the subsequent empirical chapter, I show that men are more likely to judge women they find attractive as more sexually aroused. Crucially, in a real-life dating study, I show that men who are attracted to another are more likely to assume mutual interest. Further, I introduce a framework suggesting that people align their actions and emotional states with others to foster romantic relationships. The final empirical chapter suggests that mimicking the attraction cues of others enhances bond formation. Overall, this dissertation sheds light on how attractiveness and attraction affect our attention, our social cognition, and the synchronization of actions and emotions, offering insights into the mechanisms underlying romantic connections. Show less
