30 research outputs found
Vegetation and peat accumulation steer Holocene tidal–fluvial basin filling and overbank sedimentation along the Old Rhine River, The Netherlands
In the transformation from tidal systems to freshwater coastal landscapes, plants act as eco-engineering species that reduce hydrodynamics and trap sediment, but nature and timing of the mechanisms of land creation along estuaries remains unclear. This article focuses on the Old Rhine estuary (The Netherlands) to show the importance of vegetation in coastal landscape evolution, predominantly regarding tidal basin filling and overbank morphology. This estuary hosted the main outflow channel of the river Rhine between ca 6500 to 2000 cal bp, and was constrained by peat during most of its existence. This study reconstructs its geological evolution, by correlating newly integrated geological data and new field records to varying conditions. Numerical modelling was performed to test the inferred mechanisms. It was found that floodbasin vegetation and resulting organic accumulation strongly accelerated back-barrier infill, by minimizing tidal influence. After tidal and wave transport had already sufficiently filled the back-barrier basin, reed rapidly expanded from its edges under brackish conditions, as shown by diatom analysis and datings. Reed growth provided a positive infilling feedback by reducing tidal flow and tidal prism, accelerating basin infilling. New radiocarbon dates show that large-scale crevassing along the Old Rhine River – driven by tidal backwater effect – only started as nutrient-rich river water transformed the floodbasin into an Alder carr in a next phase of estuary evolution. Such less dense vegetation promotes crevassing as sediments are more easily transported into the floodbasin. As river discharge increased and estuary mouth infilling progressed, crevasse activity diminished around 3800 to 3000 cal bp, likely due to a reduced tidal backwater effect. The insights from this data-rich Holocene study showcase the dominant role that vegetation may have in the long-term evolution of coastal wetlands. It provides clues for effective use of vegetation in vulnerable wetland landscapes to steer sedimentation patterns to strategically adapt to rising water levels
Population-Based Study on Risk Factors for Tumor-Positive Resection Margins in Patients with Gastric Cancer
Abstract
Background
Radical gastrectomy is the cornerstone of the treatment of locally advanced gastric cancer. This study was designed to evaluate factors associated with a tumor-positive resection margin after gastrectomy and to evaluate the influence of hospital volume.
Methods
In this Dutch cohort study, patients with junctional or gastric cancer who underwent curative gastrectomy between 2011 and 2017 were included. The primary outcome was incomplete tumor removal after the operation defined as the microscopic presence of tumor cells at the resection margin. The association of patient and disease characteristics with incomplete tumor removal was tested with multivariable regression analysis. The association of annual hospital volume with incomplete tumor removal was tested and adjusted for the patient- and disease characteristics.
Results
In total, 2799 patients were included. Incomplete tumor removal was seen in 265 (9.5%) patients. Factors associated with incomplete tumor removal were: tumor located in the entire stomach (odds ratio (OR) [95% confidence interval (CI): 3.38 [1.91–5.96] reference: gastroesophageal junction), cT3, cT4, cTx (1.75 [1.20–2.56], 2.63 [1.47–4.70], 1.60 [1.03–2.48], reference: cT0-2), pN+ (2.73 [1.96–3.80], reference: pN−), and diffuse and unknown histological subtype (3.15 [2.14–4.46] and 2.05 [1.34–3.13], reference: intestinal). Unknown differentiation grade was associated with complete tumor removal (0.50 [0.30–0.83], reference: poor/undifferentiated). Compared with a hospital volume of  39 resections were associated with lower probability for incomplete tumor removal (OR 0.56 [0.42–0.76] and 0.34 [0.18–0.64]).
Conclusions
Tumor location, cT, pN, histological subtype, and tumor differentiation are associated with incomplete tumor removal. The association of incomplete tumor removal with an annual hospital volume of < 20 resections may underline the need for further centralization of gastric cancer care in the Netherlands
ENIGMA and global neuroscience: A decade of large-scale studies of the brain in health and disease across more than 40 countries
This review summarizes the last decade of work by the ENIGMA (Enhancing NeuroImaging Genetics through Meta Analysis) Consortium, a global alliance of over 1400 scientists across 43 countries, studying the human brain in health and disease. Building on large-scale genetic studies that discovered the first robustly replicated genetic loci associated with brain metrics, ENIGMA has diversified into over 50 working groups (WGs), pooling worldwide data and expertise to answer fundamental questions in neuroscience, psychiatry, neurology, and genetics. Most ENIGMA WGs focus on specific psychiatric and neurological conditions, other WGs study normal variation due to sex and gender differences, or development and aging; still other WGs develop methodological pipelines and tools to facilitate harmonized analyses of "big data" (i.e., genetic and epigenetic data, multimodal MRI, and electroencephalography data). These international efforts have yielded the largest neuroimaging studies to date in schizophrenia, bipolar disorder, major depressive disorder, post-traumatic stress disorder, substance use disorders, obsessive-compulsive disorder, attention-deficit/hyperactivity disorder, autism spectrum disorders, epilepsy, and 22q11.2 deletion syndrome. More recent ENIGMA WGs have formed to study anxiety disorders, suicidal thoughts and behavior, sleep and insomnia, eating disorders, irritability, brain injury, antisocial personality and conduct disorder, and dissociative identity disorder. Here, we summarize the first decade of ENIGMA's activities and ongoing projects, and describe the successes and challenges encountered along the way. We highlight the advantages of collaborative large-scale coordinated data analyses for testing reproducibility and robustness of findings, offering the opportunity to identify brain systems involved in clinical syndromes across diverse samples and associated genetic, environmental, demographic, cognitive, and psychosocial factors
Toetscriteria voor ingegoten bekledingen
Dit verslag geeft een beschrijving van de analyse van de Deltagootproeven met ingegoten basalt, die zijn uitgevoerd in 2005. Het doelvan het onderzoek is het vinden van verbeterde toetsregels voor met gietasfalt ingegoten steenzettingen. Er zijn twee soorten ingietingen getest: (1) half ingegoten met een invieting van 8.5 cm diep (2) volledig ingegoten met een ingieting van 12.9 cm diep. Het onderzoek heeft goed inzicht gegeven in het bezwijkmechanisme. Het blijkt dat de toplaag bedreigd wordt door de opwaartse beweging tijdens het steile stijghoogtefront, in combinatie met de golfklap. Omdat meer dan de helft van de golven een opwaartse verplaatsing geven met daaropvolgend een golfklap, zal er ook sprake zijn van vermoeiing. De stabiliteit van het geheel wordt bedreigd door de cumulerende verplaatsingen als gevolg van het migrerende filtermateriaal. Ook voor diemigratie is een beweging tijdens het steile stijghoogtefront een noodzakelijke voorwaarde.Steenzettinge
Seasonal variation in productivity, chemical composition and nutrient uptake of Ulva spp. (Chlorophyta) strains
Applications ofseaweeds require the supply of uniform biomass, yet performance of Ulva is generally characterised by a wide variation across study sites and seasons, as well as among species or strains. This study aimed to determine the variation in growth, biochemical composition and nutrient uptake of five Ulva strains collected in the Eastern Scheldt estuary (theNetherlands) and cultivated under standardised outdoor conditions from July to November. Surprisingly, only two strains performed well (maximum 291 ± 95 and 570 ± 122 kg FW ha− 1 day− 1 for VEE and YER strain), one strain showed slow growth (maximum 155 ± 91 kg FW ha− 1 day− 1 for SCH strain), and the last two strains (JAC and KOM) did not grow at all. Chemical composition was only determined for the well-performing strains. For most of the parameters, strong seasonality was observed; growth, crude fat (0.4–1.3%), ash (16–25%) and starch (3–11%) decreased, whereas fibres (37–45%) and proteins (7–22% crude; 6–18% true) increased. To evaluate the bio-remediation potential, nutrient uptake of YER, VEE and SCH strains was determined from in- and outflowing water (453–2027 μmol DIN; 4–101 μmol PO4 kg FW h− 1). Highestrates were observed for the SCH strain which was not in accordance with growth nor composition, suggesting that nutrients were not (all) directed towards vegetative growth. This study demonstrates a large variation in performance between different Ulva strains collected in relatively close proximity and thereby highlights the importance to test a variety of local seaweed strains prior to commercial farming
High quality crystalline silicon surface passivation by combined intrinsic and n-type hydrogenated amorphous silicon
We investigate the influence of thermal annealing on the passivation quality of crystalline silicon (c-Si) surfaces by intrinsic and n-type hydrogenated amorphous silicon (a-Si:H) films. For temperatures up to 255 C, we find an increase in surface passivation quality, corresponding to a decreased dangling bond density. Due to the combined chemical and field effect passivation of the intrinsic/n-type a-Si:H layer stack, we obtained minority carrier lifetimes with a value as high as 13.3 ms at an injection level of 1015 cm 3. For higher annealing temperatures, a decreased passivation quality is observed, which is attributed to hydrogen effusion
High quality crystalline silicon surface passivation by combined intrinsic and n-type hydrogenated amorphous silicon
We investigate the influence of thermal annealing on the passivation quality of crystalline silicon (c-Si) surfaces by intrinsic and n-type hydrogenated amorphous silicon (a-Si:H) films. For temperatures up to 255 C, we find an increase in surface passivation quality, corresponding to a decreased dangling bond density. Due to the combined chemical and field effect passivation of the intrinsic/n-type a-Si:H layer stack, we obtained minority carrier lifetimes with a value as high as 13.3 ms at an injection level of 1015 cm 3. For higher annealing temperatures, a decreased passivation quality is observed, which is attributed to hydrogen effusion
Clinical relevance of postextrasystolic potentiation
The significance and clinical relevance of postextrasystolic potentiation resides in
the fact that any change in duration of the cardiac cycle results in a change in the
contractile behavior of the heart. Since neither a normal nor a diseased heart ever
beats strictly regularly, postextrasystolic potentiation is continuously operative,
and all hemodynamic or circulatory data obtained in the intact organism are affected by it. This means that postextrasystolic potentiation should be taken into account when cardiovascular clinical data are analyzed and subsequently used for diagnosis or treatment. Postextrasystolic potentiation used as an intervention for the evaluation of residual viabie myocardium in scar tissue areas in patients with coronary heart disease may contribute to our insights in the prognosis of and therapeutic judgments in those patients. Postextrasystolic potentiation is a fundamental physiologic property of all myocardium under all circumstances and as such does not allow for integrating or averaging data obtained during more than one cardiac cycle, if cardiac rhythm has not been strictly regular. This fact is insufficiently appreciated in nuclear cardiology and two-dimensional echocardiography