Measuring crosswind using scintillometry

This thesis demonstrates that a scintillometer is able to obtain a path-averaged value of the crosswind (i.e., wind component perpendicular to a path). A scintillometer consists of a transmitter and a receiver spaced a few hundred meters to a few kilometres apart. The transmitter emits light with a certain wavelength, which is refracted by scintillations in the atmosphere (eddies with a different temperature and moisture content than their surrounding). The atmosphere is turbulent, thus the receiver of the scintillometer measures the intensity of the fluctuations of the light. Two scintillometer setup next to each other in principle measure the same eddy field except for a time-shift. It is known that this time-shift is linked to the crosswind: the lower the time shift the stronger the crosswind. This thesis shows that experimental calibration in the field to measure the crosswind with a scintillometer is not necessary. Also we developed two new algorithms, which are able to obtain the crosswind from the scintillometer signal. First, the algorithms were validated with measurements made above a flat grassland field. Later, measurements took place over more complex terrains (i) above the city of Helsinki, Finland and (ii) next to a runway at Schiphol airport, the Netherlands. We highlight that even in these complex terrains the scintillometer was able to obtain the crosswind correctly. At Schiphol airport also other applications of scintillometry were investigated: visibility measurements, and wake vortex detection. To use scintillometers as a visibility sensor, more research is necessary. In contrast, the scintillometer proved to be able to detect wake vortices created by airplanes during the night, when the atmospheric turbulence is low.</p

WindVisions: first phase final report

It is the objective of this project to develop a Wind and Visibility Monitoring System (WindVisions) at Mainport Schiphol. WindVisions will consist of a crosswind scintillometer, which is a horizontal long range wind and visibility sensor, and a SODAR (Sound Detecting And Ranging), a vertical scanning wind sensor. The area of interest to monitor is the landing and take-off course of airplanes ranging from the surface to about 300m height along a runway

Assessment of Microvascular Disease in Heart and Brain by MRI: Application in Heart Failure with Preserved Ejection Fraction and Cerebral Small Vessel Disease

The objective of this review is to investigate the commonalities of microvascular (small vessel) disease in heart failure with preserved ejection fraction (HFpEF) and cerebral small vessel disease (CSVD). Furthermore, the review aims to evaluate the current magnetic resonance imaging (MRI) diagnostic techniques for both conditions. By comparing the two conditions, this review seeks to identify potential opportunities to improve the understanding of both HFpEF and CSVD

Observing crosswind over urban terrain using scintillometer and Doppler lidar

In this study, the crosswind (wind component perpendicular to a path, U-perpendicular to) is measured by a scintillometer and estimated with Doppler lidar above the urban environment of Helsinki, Finland, for 15 days. The scintillometer allows acquisition of a path-averaged value of U-perpendicular to ((U-perpendicular to) over bar), while the lidar allows acquisition of path-resolved U-perpendicular to (U-perpendicular to(x), where x is the position along the path). The goal of this study is to evaluate the performance of scintillometer estimates for conditions under which U-perpendicular to(x) is variable. Two methods are applied to estimate (U-perpendicular to) over bar from the scintillometer signal: the cumulative-spectrum method (relies on scintillation spectra) and the look-up-table method (relies on time-lagged correlation functions). The values of (U-perpendicular to) over bar of both methods compare well with the lidar estimates, with root-mean-square deviations of 0.71 and 0.73 ms(-1). This indicates that, given the data treatment applied in this study, both measurement technologies are able to obtain estimates of (U-perpendicular to) over bar in the complex urban environment. The detailed investigation of four cases indicates that the cumulative-spectrum method is less susceptible to a variable U-perpendicular to (x) /than the look-up-table method. However, the look-up-table method can be adjusted to improve its capabilities for estimating (U-perpendicular to) over bar under conditions under for which U-perpendicular to (x) is variable.Peer reviewe

Role of soluble endoglin in BMP9 signaling.

Endoglin (ENG) is a coreceptor of the transforming growth factor-β (TGFβ) family signaling complex, which is highly expressed on endothelial cells and plays a key role in angiogenesis. Its extracellular domain can be cleaved and released into the circulation as soluble ENG (sENG). High circulating levels of sENG contribute to the pathogenesis of preeclampsia (PE). Circulating bone morphogenetic protein 9 (BMP9), a vascular quiescence and endothelial-protective factor, binds sENG with high affinity, but how sENG participates in BMP9 signaling complexes is not fully resolved. sENG was thought to be a ligand trap for BMP9, preventing type II receptor binding and BMP9 signaling. Here we show that, despite cell-surface ENG being a dimer linked by disulfide bonds, sENG purified from human placenta and plasma from PE patients is primarily in a monomeric form. Incubating monomeric sENG with the circulating form of BMP9 (prodomain-bound form) in solution leads to the release of the prodomain and formation of a sENG:BMP9 complex. Furthermore, we demonstrate that binding of sENG to BMP9 does not inhibit BMP9 signaling. Indeed, the sENG:BMP9 complex signals with comparable potency and specificity to BMP9 on human primary endothelial cells. The full signaling activity of the sENG:BMP9 complex required transmembrane ENG. This study confirms that rather than being an inhibitory ligand trap, increased circulating sENG might preferentially direct BMP9 signaling via cell-surface ENG at the endothelium. This is important for understanding the role of sENG in the pathobiology of PE and other cardiovascular diseases.British Heart Foundation, Cancer Genomics Centre Netherlands and from the Netherlands CardioVascular Research Initiative, the Dutch Heart Foundation, Dutch Federation of University Medical Centers, the Netherlands Organization for Health Research and Development, and the Royal Netherlands Academy of Sciences (CVON PHEADRA)

Liposome induction of CD8+ T cell responses depends on CD169+ macrophages and Batf3-dependent dendritic cells and is enhanced by GM3 inclusion

Cancer vaccines aim to efficiently prime cytotoxic CD8+ T cell responses which can be achieved by vaccine targeting to dendritic cells. CD169+ macrophages have been shown to transfer antigen to dendritic cells and could act as an alternative target for cancer vaccines. Here, we evaluated liposomes containing the CD169/Siglec-1 binding ligand, ganglioside GM3, and the non-binding ligand, ganglioside GM1, for their capacity to target antigens to CD169+ macrophages and to induce immune responses. CD169+ macrophages demonstrated specific uptake of GM3 liposomes in vitro and in vivo that was dependent on a functional CD169 receptor. Robust antigen-specific CD8+ and CD4+ T and B cell responses were observed upon intravenous administration of GM3 liposomes containing the model antigen ovalbumin in the presence of adjuvant. Immunization of B16-OVA tumor bearing mice with all liposomes resulted in delayed tumor growth and improved survival. The absence of CD169+ macrophages, functional CD169 molecules, and cross-presenting Batf3-dependent dendritic cells (cDC1s) significantly impaired CD8+ T cell responses, while B cell responses were less affected. In conclusion, we demonstrate that inclusion of GM3 in liposomes enhance immune responses and that splenic CD169+ macrophages and cDC1s are required for induction of CD8+ T cell immunity after liposomal vaccination

Evaluation of miCRovascular rarefaction in vascUlar Cognitive Impairment and heArt faiLure (CRUCIAL): Study protocol for an observational study

INTRODUCTION: Microvascular rarefaction, the functional reduction in perfused microvessels and structural reduction of microvascular density, seems to be an important mechanism in the pathophysiology of small blood vessel related disorders including vascular cognitive impairment (VCI) due to cerebral small vessel disease and heart failure with preserved ejection fraction (HFpEF). Both diseases share common risk factors including hypertension, diabetes mellitus, obesity, and ageing; in turn, these co-morbidities are associated with microvascular rarefaction. Our consortium aims to investigate novel non-invasive tools to quantify microvascular health and rarefaction in both organs, as well as surrogate biomarkers for cerebral and/or cardiac rarefaction (via sublingual capillary health, vascular density of the retina, and RNA content of circulating extracellular vesicles), and to determine whether microvascular density relates to disease severity. METHODS/DESIGN: The clinical research program of CRUCIAL consists of four observational cohort studies. We aim to recruit 75 VCI patients, 60 HFpEF patients, 60 patients with severe aortic stenosis (AS) undergoing surgical aortic valve replacement as a pressure overload HFpEF model, and 200 elderly participants with mixed comorbidities to serve as controls. Data collected will include medical history, physical examination, cognitive testing, advanced brain and cardiac MRI, ECG, echocardiography, sublingual capillary health, optical coherence tomography angiography (OCTa), extracellular vesicles RNA analysis and myocardial remodelling-related serum biomarkers. The AS cohort undergoing surgery will also have myocardial biopsy for histological microvascular assessment. DISCUSSION: CRUCIAL will examine the pathophysiological role of microvascular rarefaction in VCI and HFpEF using advanced brain and cardiac MRI techniques. Furthermore, we will investigate surrogate biomarkers for non-invasive, faster, easier, and cheaper assessment of microvascular density since these are more likely to be disseminated into widespread clinical practice. If microvascular rarefaction is an early marker of developing small vessel diseases, then measuring rarefaction may allow pre-clinical diagnosis, with implications for screening, risk stratification, and prevention. Further knowledge of the relevance of microvascular rarefaction and its underlying mechanisms may provide new avenues for research and therapeutic targets