Radboud University
  • Nijmegen, Netherlands
Recent publications
A key challenge in oligosaccharide synthesis is the stereoselective installation of glycosidic bonds. Each glycosidic linkage has one of two possible stereo‐chemical geometries, α/β or 1,2‐cis/trans. An established approach to install 1,2‐trans glycosidic bonds is neighboring group participation (NGP), mediated by a 2‐O‐acyl group. Extension of this intramolecular stabilization to nucleophilic groups located at more remote positions has also been suggested, but remains poorly understood. Previously, we employed infrared ion spectroscopy to characterize the molecular ions of monoacetylated sugar donors and showed how the strength of the stabilizing effect depends on the position of the participating ester group on the glycosyl donor ring as well as on its relative stereochemistry. In this work, we investigated glycosyl donors carrying two acyl groups. Using isotope labelling and isomer population analysis we were able to resolving spectra of isomeric mixtures and establish the relative contribution of individual species. We conclude that 3,4‐diacetyl mannosyl donors exclusively form a dioxanium ion as a result of C‐3 acyl stabilization. In contrast, the glucosyl and galactosyl cations form mixtures of C‐3 and C‐4 acyl participation products. Hence, the combination of isotope labeling and population analysis allows for the study of increasingly complex glycosyl cations.
Phase‐separated compartments can localize (bio)chemical reactions and influence their kinetics. They are believed to play an important role both in extant life in the form of biomolecular condensates and at the origins of life as coacervate protocells. However, experimentally testing the influence of coacervates on different reactions is challenging and time‐consuming. We therefore use a numerical model to explore the effect of phase‐separated droplets on the kinetics and outcome of different chemical reaction systems, where we vary the coacervate volume and partitioning of reactants. We find that the rate of bimolecular reactions has an optimal dilute/coacervate phase volume ratio for a given reactant partitioning. Furthermore, coacervates can accelerate polymerization and self‐replication reactions and lead to formation of longer polymers. Lastly, we find that coacervates can ‘rescue’ oscillating reaction networks in concentration regimes where sustained oscillations do not occur in a single‐phase system. Our results indicate that coacervates can direct the outcome of a wide range of reactions and impact fundamental aspects such as yield, reaction pathway selection, product length and emergent functions. This may have far‐reaching implications for origins of life, synthetic cells and the fate and function of biological condensates.
Cyclobutanes have attracted significant interest in medicinal chemistry because of their unique structure and potential advantages in pharmacological properties. Nevertheless, 1,2‐disubstituted cyclobutanes remain underrepresented, both in the general chemical space and in fragment‐based drug discovery libraries. In this study, a two‐diversification‐point library of cyclobutanesulfonamides was synthesized through a hyperbaric [2+2] cycloaddition reaction between ethenesulfonyl fluoride and tert‐butyl vinyl ether as the key step. The sulfonyl fluoride was subsequently transformed into various sulfonamides, whereas the tert‐butyl ether was converted into carbamates and triazoles to synthesize a fragment library. Overall, this synthesis contributes to addressing the underrepresentation of 1,2‐disubstituted cyclobutane fragments, making a valuable addition to the field of fragment‐based drug discovery.
Plain Language Summary This study proposes a computer vision approach to develop an automated scoring system for the adapted visual-spatial test with a data size of less than 1000 This study proposes a computer vision approach to develop an automated scoring system for the adapted visual-spatial test with a data size of less than 1000. This study facilitated the practitioner in developing a standardized and objective scoring system for a visual-spatial test (FRT-CVAS/Figural Reproduction Test—Computer Vision Automated Scoring System). The spatial test is one of the standard tests adapted and used in many countries. The stimulus could be different in each adaptation process, but the main part is always the same: the geometric stimulus. The number of hand-drawn responses is limited in the early adaptation, so this approach can be implemented in small-data training. The research team collected the 420 hand-drawn data from the Figural Reproduction Test as a part of the Neuropsychology Battery Test adapted in Indonesia. The study compared the manual scoring and automated scoring systems. The scoring of a hand-drawn geometrical figure by human raters has subjective elements. In the Figure Reproduction Test (FRT), these subjective factors are particularly notable in the judgment of the correct shape of triangles. The scoring accuracy can be improved somewhat by using single criteria instead of the compound criteria suggested in the scorer’s manual. FRT-CVAS, which is a computer vision approach, further removes such subjectivity: by extracting and evaluating all of the hand-drawn elements in detail, it achieves high-level accuracy, sensitivity, and reasonable specificity. FRT-CVAS achieves a more standardized, consistent, precise, and objective result.
Purpose An emerging group of patients lives longer with advanced cancer while receiving systemic treatment. This study aimed to investigate psychosocial aspects of living longer with advanced cancer, and experiences with psychosocial care, from the perspectives of patients, partners, and health care professionals (HCPs). Methods From May to December 2020, participants were purposively selected. In-depth, semi-structured interviews were conducted by video or phone call, containing open questions regarding psychosocial aspects and psychosocial care in oncology. The data was analysed following thematic analysis, leading to overarching psychosocial themes and indications for optimal organisation of psycho-oncological care. Results Fifteen patients, seven partners and eleven HCPs were interviewed. The main psychosocial aspects were increasing loss in several life domains, complexity of making life choices, ongoing uncertainty, and fluctuating fear and hope. Partners were affected by their loved ones’ condition and reported to put themselves second for longer periods of time, while sometimes missing adequate support. HCPs were challenged by addressing the altering psychosocial needs of patients, and tools to identify those in need for psychosocial support are currently lacking. Conclusions Living longer with advanced cancer presents unique challenges for patients and their partners, as well as for HCPs in delivering optimal psychosocial care. Implications for Cancer Survivors Identifying and addressing patients’ psychosocial needs from an early stage on, appointing a central hospital-based contact person, limiting the waiting time between scans and consultations, and addressing the partners’ wellbeing are suggestions to organise optimal psychosocial support in advanced cancer.
Many studies have observed a correlation between beliefs regarding nature's resilience and (political) preferences regarding the organization of society. Liberal‐egalitarians, for example, generally believe nature to be much more fragile than libertarians, who believe nature to be much more resilient. Cultural theory explains this correlation by the idea that people are only able to see those risks that fit their preferred organization of society. This article offers an alternative, second explanation for the observed correlation: Both beliefs regarding nature's resilience and political preferences can be explained by the same cognitive biases toward ambiguous risk, that is, dispositions determining our expectations regarding the possible state of affairs resulting from our acts and their probabilities. This has consequences for political philosophy and the psychology of risk. In particular, there is a knowledge gap in psychology regarding the cognitive biases underlying the belief that despite ambiguity, experts can determine safe limits for human impacts on the environment.
Previous studies based on animal models have raised concerns about salbutamol use in ozone air pollution with regard to ozone related lung injury. We conducted a double‐blind, randomized, placebo‐controlled crossover study including 18 subjects diagnosed with EIB by a eucapnic voluntary hyperpnea (EVH) test. Participants completed 30 min of standardized moderate to vigorous exercise in four conditions: ozone plus salbutamol; room air plus salbutamol; ozone plus placebo medication; and room air plus placebo medication. Spirometry, fraction of exhaled nitric oxide, and symptoms were measured before, immediately after, 30 min after and 1 h after exercise. Measurements between the four conditions were compared using percent change from pre to post exercise. There was a statistically significant difference between the salbutamol and placebo medication groups for spirometric variables including FEV1 (Estimate = 6.3, 95% CI: 4.23–8.37, p < 0.001). No differences were observed between ozone and room air exposures. There were no significant differences in FeNO response between experimental conditions. We found that salbutamol improved pulmonary function in individuals with EIB when exercising in ozone and did not increase eosinophilic airway inflammation as indicated by FeNO. This evidence suggests that it is safe for people with EIB to continue to use salbutamol as proscribed when ozone levels are elevated.
Throughout the twentieth century, considerable research has been dedicated to understanding the rise, development and end of ancient cities. In recent years, there has been a remarkable upsurge of new methodological and theoretical approaches applied in urbanism studies, which enables us to improve, validate or question our knowledge about ancient urban life. The three books reviewed here concern the development, transformation and experience of ancient Roman cities; leading experts in urban history and archaeology discussing the potential of new technologies and conceptual frameworks for analysing Roman urban space.
Alzheimer’s disease (AD) is a multifactorial disease with both genetic and environmental factors contributing to its etiology. Previous evidence has implicated disturbed insulin signaling as a key mechanism that plays a role in both neurodegenerative diseases such as AD and comorbid somatic diseases such as diabetes mellitus type 2 (DM2). In this study, we analysed available genome-wide association studies (GWASs) of AD and somatic insulin-related diseases and conditions (SID), i.e., DM2, metabolic syndrome and obesity, to identify genes associated with both AD and SID that could increase our insights into their molecular underpinnings. We then performed functional enrichment analyses of these genes. Subsequently, using (additional) GWAS data, we conducted shared genetic etiology analyses between AD and SID, on the one hand, and blood and cerebrospinal fluid (CSF) metabolite levels on the other hand. Further, integrating all these analysis results with elaborate literature searches, we built a molecular landscape of the overlap between AD and SID. From the landscape, multiple functional themes emerged, including insulin signaling, estrogen signaling, synaptic transmission, lipid metabolism and tau signaling. We also found shared genetic etiologies between AD/SID and the blood/CSF levels of multiple metabolites, pointing towards “energy metabolism” as a key metabolic pathway that is affected in both AD and SID. Lastly, the landscape provided leads for putative novel drug targets for AD (including MARK4, TMEM219, FKBP5, NDUFS3 and IL34) that could be further developed into new AD treatments.
Society - and the way it is organized - along with families, shapes who is available and suitable as a partner, who we encounter, what traits we seek in a partner, and who we form relationships with. In turn, our partner choices impact society at large. Given this bidirectional relationship, partner selection is expected to evolve alongside broader societal changes influenced by factors such as economic shifts, wars, migration, and sociocultural transformations like secularization, feminist movements, and sexual revolutions. The central question of this special issue is how societal transformations have influenced long-term trends in partner preferences and choices. This is being explored through new sources - online genealogies, matrimonial and contact advertisements, data from marriage agencies and dating apps – and approaches.
People often exhibit intertemporal impatience by choosing immediate small over delayed larger rewards, which has been implicated across maladaptive behaviours and mental health symptoms. In this preregistered study, we tested the role of an intertemporal Pavlovian bias as possible psychological mechanism driving the temptation posed by immediate rewards. Concretely, we hypothesized that the anticipation of immediate rewards (compared with preference-matched delayed rewards) enhances goal-directed approach behaviour but interferes with goal-directed inhibition. Such a mechanism could contribute to the difficulty to inhibit ourselves in the face of immediate rewards (e.g., a drug), at the cost of long-term (e.g., health) goals. A sample of 184 participants completed a newly developed reinforcement learning go/no-go task with four trial types: Go to win immediate reward; Go to win delayed reward; No-go to win immediate reward; and No-go to win delayed reward trials. Go responding was increased in trials in which an immediate reward was available compared with trials in which a preference-matched delayed reward was available. Computational models showed that on average, this behavioural pattern was best captured by a cue-response bias reflecting a stronger elicitation of go responses upon presentation of an immediate (versus delayed) reward cue. The results of this study support the role of an intertemporal Pavlovian bias as a psychological mechanism contributing to impatient intertemporal choice.
In April 2020, in the midst of its first pandemic lockdown, the Dutch government announced plans to develop a contact tracing app to help contain the spread of the coronavirus – the Coronamelder. Originally intended to address the problem of the overburdening of manual contract tracers, by the time the app was released six months later, the problem it sought to solve had drastically changed, without the solution undergoing any modification, making it a prime example of technosolutionism. While numerous critics have mobilised the concept of technosolutionism, the questions of how technosolutionism works in practice and which specific harms it can provoke have been understudied. In this paper we advance a thick conception of technosolutionism which, drawing on Evgeny Morozov, distinguishes it from the notion of technological fix, and, drawing on constructivism, emphasizes its constructivist dimension. Using this concept, we closely follow the problem that the Coronamelder aimed to solve and how it shifted over time to fit the Coronamelder solution, rather than the other way around. We argue that, although problems are always constructed, technosolutionist problems are badly constructed, insofar as the careful and cautious deliberation which should accompany problem construction in public policy is absent in the case of technosolutionism. This can lead to three harms: a subversion of democratic decision-making; the presence of powerful new actors in the public policy context – here Big Tech; and the creation of “orphan problems”, whereby the initial problems that triggered the need to develop a (techno)solution are left behind. We question whether the most popular form of technology ethics today, which focuses predominantly on the design of technology, is well-equipped to address these technosolutionist harms, insofar as such a focus may preclude critical thinking about whether or not technology should be the solution in the first place.
To understand human learning and progress, it is crucial to understand curiosity. But how consistent is curiosity’s conception and assessment across scientific research disciplines? We present the results of a large collaborative project assessing the correspondence between curiosity measures in personality psychology and cognitive science. A total of 820 participants completed 15 personality trait measures and 9 cognitive tasks that tested multiple aspects of information demand. We show that shared variance across the cognitive tasks was captured by a dimension reflecting directed (uncertainty-driven) versus random (stochasticity-driven) exploration and individual differences along this axis were significantly and consistently predicted by personality traits. However, the personality metrics that best predicted information demand were not the central curiosity traits of openness to experience, deprivation sensitivity, and joyous exploration, but instead included more peripheral curiosity traits (need for cognition, thrill seeking, and stress tolerance) and measures not traditionally associated with curiosity (extraversion and behavioral inhibition). The results suggest that the umbrella term “curiosity” reflects a constellation of cognitive and emotional processes, only some of which are shared between personality measures and cognitive tasks. The results reflect the distinct methods that are used in these fields, indicating a need for caution in comparing results across fields and for future interdisciplinary collaborations to strengthen our emerging understanding of curiosity.
Extreme weather impacts due to climate change, such as urban pluvial flooding, necessitate adaptive measures. To support decision making in climate adaptation, climate services provide information and guidance to policy makers and other stakeholders. Effective use of climate services is prohibited by usability gaps. Some causes for these gaps originate from contextual factors. However, these factors are not well understood within academic literature. Therefore, our systematic review has two research questions: (1) What dimensions of climate service usability are considered in the design and evaluation of their use and how are these operationalized?; and (2) What contextual influences may affect these identified dimensions? To this end, we analyzed 51 articles that cover one or more urban pluvial flooding climate services. Our results show several overarching categories of usability dimensions (functionality, ease of use, reducing time and effort, reliability, matching user needs, and other). However, these dimensions are not always fully operationalized by authors. Furthermore, our results show that most contextual factors originate from the meso level (within or between organizations), and in lesser extent the macro (e.g., national policies) and micro level (individual users). Here especially organizational (e.g., Does the climate service fit organizational work approaches?); and process factors (e.g., Was the climate service co‐produced?) have been shown to affect usability. We conclude that more attention should be given to usability as a concept within the design and evaluation of climate services well as to the influence of contextual influences.
This study investigated the reciprocal relationship between self-perceived employability (SPE) and psychological well-being (PWB), a connection previously suggested by theory but not yet explored empirically in early career research. Drawing from the Conservation of Resources theory, we analysed the reciprocal effects between SPE and PWB. Using data collected from 376 Italian university students and graduates, we tested the hypotheses with the random intercept cross-lagged panel model (RI-CLPM) to analyse the SPE-PWB reciprocal linkage at both the between-person and within-person levels. While we observed a reciprocal SPE-PWB association across three waves at the between-person level, we obtained mixed findings at the within-person level. This study is the first to test the reciprocal associations between SPE and PWB among labour market entrants adopting a within-person approach. The findings offer new empirical insights into SPE during early career stages, with implications for both future research and practical applications.
With the exponential growth of digitized historical materials, historians and social scientists face the daunting task of navigating vast online collections. While online archives do provide search tools to query their materials, these usually do not meet the scholars’ need to trace and store all relevant materials from the online archive. This case study shows how computer vision methods, and more specifically a signal processing approach, can be used to identify, classify and extract relevant information items from a vast historical datacollection. More specifically, this study reports the results of the construction of a data pipeline that extracts matrimonial advertisements from the digitized Catalan newspaper La Vanguardia. Matrimonial advertisements can provide genuine insights into the evolution of partner preferences over time, but they are hard to collect as they are scattered over millions of digitized historical newspapers and magazines. Moreover, to study variation in partner preferences by, for example, sex, social class, matrimonial statusand time period, it is necessary to store the data into a database. The pipeline that we have constructed extracts matrimonial advertisements in a stepwise fashion, encompassing identification, through binarisation and segmentation, and classification based on Optical Character Recognition. By ways of a comprehensive evaluation, both qualitatively and quantitatively, the efficacy ofthe pipeline for the extraction of matrimonial advertisements is demonstrated. The findings not only underscore the viability of the signal processing approach but also underscore its potential for advancing research in historical demography, family history, as well as economic history, as similar pipelines can be set up to extract other relevant newspaper items, such as, marriage, birth, death and moving announcements, job vacancies or business announcements from digitized source collections
Across Europe, Public Service Media (PSM) are increasingly subject to bias accusations in public debates. Excluding academic attention for actual bias in news content, research into the nature of bias accusations is limited. This article studies bias accusations against Dutch PSM in online discourse. Through a qualitative content analysis of tweets and blogs (2017–2022), our analysis develops a novel typology of bias accusations—positional, information, and framing bias—going beyond academic definitions. Bias accusations are diverse in nature, reflect strong perceived intentionality, and refer to heterogeneous social, political groups, yet are easily merged into singular political ideological divides.
We know that populism influences turnout and vote choice. Yet, we know surprisingly little about how populism drives broader participation patterns. In this study, we argue that populist citizens are more likely to participate in politics beyond the electoral arena because they hold specific political grievances. Extant literature highlights the multidimensionality of participation but remains ambiguous about how many or what dimensions it entails. We rely on an unprecedented 16-item participation battery from a comparative survey in nine European countries to design distinct theoretical and empirical lenses through which to examine the relationship between populist attitudes and political participation. The former relies on operationalisations from the literature that are confirmed by confirmatory factor analysis, while the latter relies on latent class analysis. Both frameworks return similar results, highlighting that populist citizens are effectively more likely to participate across the board, regardless of the form or classification of political participation.
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16,746 members
Tim Frenzel
  • Department of Intensive Care
Taco Brandsen
  • Faculty of Management
Hans Maassen
  • Department of Mathematics
Joachim Reimann
  • Department of Microbiology
Paula Fikkert
  • Centre for Language Studies
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Nijmegen, Netherlands
Head of institution
Gerard Meijer