Publications by authors named "Visser P"

Article Synopsis
  • Understanding the interphase regions in epoxy resins is crucial for enhancing their mechanical properties, like fracture strength and barrier performance, as these areas are often weak spots.
  • Conventional methods struggle to analyze these nanoscale regions, making it hard to understand their formation processes.
  • By using molecular dynamics simulations and infrared mapping, researchers discovered that binding interactions of the amine cross-linker with various metal oxide surfaces affect binding energies, while also revealing that an excess of reactive materials remains near the particles, indicating potential undercuring in the matrix.
View Article and Find Full Text PDF

This study aimed to identify ocean- and land-based sources of nutrients to the coral reef communities surrounding the Southern Caribbean islands Aruba, Bonaire, and Curaçao (ABC islands). The composition of water masses around these islands were assessed to depths up to 300 m and three distinct overlying water masses were identified, separated by mixing zones. A fluctuating pycnocline separating surface from deeper (>∼50 m) water indicated the presence of internal waves.

View Article and Find Full Text PDF

The integration of quantitative trait loci (QTLs) with disease genome-wide association studies (GWASs) has proven successful in prioritizing candidate genes at disease-associated loci. QTL mapping has been focused on multi-tissue expression QTLs or plasma protein QTLs (pQTLs). We generated a cerebrospinal fluid (CSF) pQTL atlas by measuring 6,361 proteins in 3,506 samples.

View Article and Find Full Text PDF

This preclinical AD CSF proteome study identified a panel of 12-CSF markers detecting amyloid positivity and clinical progression to AD with high accuracy; some of these CSF proteins related to immune function, neurotrophic processes, energy metabolism and endolysosomal functioning (e.g., ITGB2, CLEC5A, IGFBP-1, CST3) changed before amyloid positivity is established.

View Article and Find Full Text PDF

Introduction: Physical function and cognition seem to be interrelated, especially in the oldest-old. However, the temporal order in which they are related and the role of brain health remain uncertain.

Methods: We included 338 participants (mean age 93.

View Article and Find Full Text PDF
Article Synopsis
  • * In Alzheimer's disease, these networks become more chaotic, as indicated by a drop in the small-world coefficient, a change linked to cognitive decline throughout the disease's progression.
  • * Our study examined the relationship between 10 cerebrospinal fluid protein biomarkers and small-world coefficients in Alzheimer's mutation carriers and non-carriers, finding that certain protein abnormalities indicate early changes in grey matter networks, while markers for inflammation and axonal injury correlate with declining small-world values.
View Article and Find Full Text PDF

Purpose: To investigate if changes in vessel density (VD) and the foveal avascular zone (FAZ) occur in the preclinical phase of Alzheimer's disease (pAD) over time.

Methods: Optical coherence tomography angiography (OCTA) was used to image VD and FAZ at baseline and for a follow-up period of 2 years. Positron emission tomography (PET) was used to determine the amyloid beta (Aβ) status of participants.

View Article and Find Full Text PDF

Background And Objectives: Vascular risk factors (VRFs) and cerebral small vessel disease (cSVD) are common in patients with Alzheimer disease (AD). It remains unclear whether this coexistence reflects shared risk factors or a mechanistic relationship and whether vascular and amyloid pathologies have independent or synergistic influence on subsequent AD pathophysiology in preclinical stages. We investigated links between VRFs, cSVD, and amyloid levels (Aβ) and their combined effect on downstream AD biomarkers, that is, CSF hyperphosphorylated tau (P-tau), atrophy, and cognition.

View Article and Find Full Text PDF

Toxic cyanobacterial blooms impose a health risk to recreational users, and monitoring of cyanobacteria and associated toxins is required to assess this risk. Traditionally, monitoring for risk assessment is based on cyanobacterial biomass, which assumes that all cyanobacteria potentially produce toxins. While these methods may be cost effective, relatively fast, and more widely accessible, they often lead to an overestimation of the health risk induced by cyanotoxins.

View Article and Find Full Text PDF
Article Synopsis
  • Blood-derived DNA methylation shows potential for early detection of dementia risk, linking biological factors with lifestyle and environmental influences.
  • A multivariate methylation risk score (MMRS) was developed, predicting mild cognitive impairment independently of age and sex, alongside significant future risk of cognitive decline in Alzheimer’s and Parkinson’s diseases.
  • The study highlights the integration of machine learning and omics data to enhance dementia risk prediction at the population level.
View Article and Find Full Text PDF
Article Synopsis
  • The study examined DNA methylation patterns in blood samples related to 15 key biomarkers of Alzheimer's disease, focusing on neuroinflammation and neurodegeneration effects.
  • Using 885 samples from the EMIF-AD study, researchers identified significant differential methylation connected to CSF levels of YKL-40 and neurofilament light chain (NfL).
  • Findings suggest a link between YKL-40 DNA methylation and genetic variants, with implications for understanding how DNA methylation influences protein levels relevant to Alzheimer's disease.
View Article and Find Full Text PDF

The synthetic potential of substituted 1,4-dioxenes is well recognised, although the chemistry of 2-aryl-1,4-dioxenes is relatively unexplored. Their transition metal-catalysed synthesis has been limited to Stille-type cross-coupling chemistry, typically showing long reaction times, or proceeding at high reaction temperatures. Here we present a facile and general methodology for the cross-coupling of aryl bromides with lithium 1,4-dioxene, affording a range of 2-aryl-1,4-dioxenes in generally good yields.

View Article and Find Full Text PDF

Positional information is key for particles to adapt their behavior based on their position in external concentration gradients, and thereby self-organize into complex patterns. Here, position-dependent behavior of floating surfactant droplets that self-organize in a pH gradient is demonstrated, using the Marangoni effect to translate gradients of surface-active molecules into motion. First, fields of surfactant microliter-droplets are generated, in which droplets floating on water drive local, outbound Marangoni flows upon dissolution of surfactant and concomitantly grow myelin filaments.

View Article and Find Full Text PDF

Purpose: Visual interpretation of brain amyloid-β (Aβ) PET can be difficult in individuals with borderline Aβ burden. Coregistration with individual MRI is recommended in these cases, which, however, is not always available. This study evaluated coregistration with the early perfusion frames acquired immediately after tracer injection to support the visual interpretation of the late Aβ-frames in PET with 18F-flutemetamol (FMM).

View Article and Find Full Text PDF
Article Synopsis
  • The study investigated the relationship between glucose metabolism and the development of tau pathology, a hallmark of Alzheimer's disease, in middle-aged adults without dementia.
  • Researchers analyzed data from 288 participants, examining their fasting plasma glucose and insulin levels and later PET scans for amyloid-β and tau loads.
  • Results showed that elevated plasma glucose correlated with increased tau load after 14 years, particularly in individuals who were not carriers of the APOE ε4 allele, while insulin levels and HOMA-IR did not show significant associations with either amyloid-β or tau.
View Article and Find Full Text PDF
Article Synopsis
  • The study explores the genetic risk factors for Alzheimer's disease (AD) and their connection to various brain changes, aiming to enhance precision medicine strategies.
  • Researchers calculated specific genetic risk scores in healthy individuals to see how these scores correlate with AD-related biomarkers found in cerebrospinal fluid and imaging techniques.
  • Findings show that different genetic pathways link to distinct brain conditions, such as inflammation affecting vascular health and other pathways influencing white matter and brain connectivity, highlighting the complexity of AD and its potential for personalized treatment approaches.
View Article and Find Full Text PDF

Objectives: The implementation of disease-modifying treatments for Alzheimer's Disease (AD) will require cost-effective diagnostic processes. As part of The Precision Medicine In AD consortium (PMI-AD) project, the aim is to analyze the baseline costs of diagnosing early AD at memory clinics in Norway, Slovenia, and the Netherlands.

Methods: The costs of cognitive testing and a clinical examination, apolipoprotein E, magnetic resonance imaging (MRI), cerebrospinal fluid (CSF), positron emission tomography and blood-based biomarkers (BBM), which are used in different combinations in the three countries, were analyzed.

View Article and Find Full Text PDF

Background: Structural and functional changes of the choroid plexus (ChP) have been reported in Alzheimer's disease (AD). Nonetheless, the role of the ChP in the pathogenesis of AD remains largely unknown. We aim to unravel the relation between ChP functioning and core AD pathogenesis using a unique proteomic approach in mice and humans.

View Article and Find Full Text PDF
Article Synopsis
  • The study investigated the role of neurodegeneration markers (neurogranin, neurofilament light, and hippocampal volume) in Alzheimer's disease using cerebrospinal fluid proteomics.
  • A small number of individuals exhibited both amyloid and tau pathology with either neurogranin or neurofilament light, showing distinct proteomic profiles based on these markers.
  • The findings suggest that neurogranin might not be the best indicator of neurodegeneration and that different markers provide unique insights into the disease, helping refine staging beyond just amyloid and tau levels.
View Article and Find Full Text PDF

Quorum sensing enables unicellular organisms to probe their population density and perform behavior that exclusively occurs above a critical density. Quorum sensing is established in emulsion droplet swarms that float at a water surface and cluster above a critical density. The design involves competition between 1) a surface tension gradient that is generated upon release of a surfactant from the oil droplets, and thereby drives their mutual repulsion, and 2) the release of a surfactant precursor from the droplets, that forms a strong imine surfactant which suppresses the surface tension gradient and thereby causes droplet clustering upon capillary (Cheerios) attraction.

View Article and Find Full Text PDF

Background: There is good evidence that elevated amyloid-β (Aβ) positron emission tomography (PET) signal is associated with cognitive decline in clinically normal (CN) individuals. However, it is less well established whether there is an association between the Aβ burden and decline in daily living activities in this population. Moreover, Aβ-PET Centiloids (CL) thresholds that can optimally predict functional decline have not yet been established.

View Article and Find Full Text PDF

Background And Objectives: Discordance between CSF and PET biomarkers of β-amyloid (Aβ) might reflect an imbalance between soluble and aggregated species, possibly reflecting disease heterogeneity. Previous studies generally used binary cutoffs to assess discrepancies in CSF/PET biomarkers, resulting in a loss of information on the extent of discordance. In this study, we (1) jointly modeled Aβ-CSF/PET data to derive a continuous measure of the imbalance between soluble and fibrillar pools of Aβ, (2) investigated factors contributing to this imbalance, and (3) examined associations with cognitive trajectories.

View Article and Find Full Text PDF

Introduction: Recent genome-wide association studies (GWAS) have reported a genetic association with Alzheimer's disease (AD) at the TNIP1/GPX3 locus, but the mechanism is unclear.

Methods: We used cerebrospinal fluid (CSF) proteomics data to test (n = 137) and replicate (n = 446) the association of glutathione peroxidase 3 (GPX3) with CSF biomarkers (including amyloid and tau) and the GWAS-implicated variants (rs34294852 and rs871269).

Results: CSF GPX3 levels decreased with amyloid and tau positivity (analysis of variance P = 1.

View Article and Find Full Text PDF

Background: Alzheimer's disease (AD) is a neurodegenerative condition for which there is currently no available medication that can stop its progression. Previous studies suggest that mild cognitive impairment (MCI) is a phase that precedes the disease. Therefore, a better understanding of the molecular mechanisms behind MCI conversion to AD is needed.

View Article and Find Full Text PDF