144 results on '"P. Schakel"'
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2. Ongelijke politieke vertegenwoordiging van opleidingsgroepen in Nederland.
- Author
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Schakel, Wouter
- Published
- 2022
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3. Technology review of the Northern Bowen and Galilee basins
- Author
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Scott, Michael P., Johnson Jr, Raymond, Spilsbury-Schakel, Janny, and Garnett, Andrew
- Abstract
This paper reviews and summarises the work that has been conducted and the technology used in exploring and developing the Northern Bowen and Galilee basins in Queensland. It examines the methods operators have used in drilling, completing and testing wells through the varying stages of exploration, appraisal and development in the different parts of the basins. It examines all the work conducted in the Betts Creek Beds and Aramac Coal Measures throughout the Galilee Basin; the Moranbah Coal Measures, Rangal Coal Measures and Fort Cooper Coal Measures in the Moranbah area of the Bowen Basin; the Rangal Coal Measures, Burngrove Formation and Fairhill Formation in the Blackwater area; the conventional and coal seam gas developments in the Rolleston area, including the Bandanna Formation plays near Injune; and the Baralaba Coal Measures in the Moura area. Wells have been completed both open and cased hole with techniques including vertical wells, both with and without hydraulic fracturing and cavitation, as well as a variety of horizontal well designs including surface to inseam wells with vertical intercept wells and multiple lateral sections, chevron wells and both heel and toe intercepts. Operators have also implemented multiple wells on one pad. Throughout the Northern Bowen Basin, horizontal well drilling has been a key technology in commercial development. Generally, activities within the Galilee Basin have not progressed as far as the Bowen Basin, but nevertheless, horizontal wells are also emerging as a key technology.
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- 2023
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4. Internationalisation and study success: class attendance and the delicate balance between collaborative learning and being lost in translation
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Bijsmans, Patrick, Schakel, Arjan H., Baykal, Asena, and Hegewald, Sven
- Abstract
ABSTRACTThe internationalisation of Higher Education is broadly seen as a positive development. It is a process that is said to contribute to intercultural skills acquisition, which is deemed crucial in today’s globalised society. Yet, research has shown that the benefits of being confronted with other ideas and viewpoints can get lost in translation due to different languages and academic cultures. We set out to explore the impact of the international classroom on study success and argue that there might be an optimum level of internationalisation. Based on a dataset that includes more than 2822 GPA scores for 836 students from four first-year cohorts of an international Bachelor in European Studies, we find strong empirical evidence that students’ study success is lower when there are few (below 3) or many (above 6) different nationalities in the classroom. We find the strongest effects of internationalisation for students who regularly attend class (i.e. 80–90%). Hence, we present strong evidence that internationalisation has a both a negative and a positive impact on students’ study success but students will only experience these beneficial and detrimental effects of learning in an international environment when they attend class.
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- 2022
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5. Car-Following Properties of a Commercial Adaptive Cruise Control System: A Pilot Field Test
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Raju, Narayana, Schakel, Wouter, Reddy, Nagarjun, Dong, Yongqi, and Farah, Haneen
- Abstract
Automated driving systems, which can take over certain dynamic driving tasks from the driver, are becoming increasingly available in commercial vehicles. One of these automated driving systems widely introduced in commercial vehicles is adaptive cruise control (ACC). This system is designed to maintain certain desired driving speeds and time headways as chosen by drivers and based on the settings available within the system. The properties and actual performance of these systems will affect the traffic flow and its stability. However, the specific properties and their workings are rarely publicly available. Therefore, the main aim of this paper is to test the actual performance of a commercial ACC system under different desired speed and distance gap settings, as well as driving modes in a car-following situation. For this purpose, a pilot field test was conducted in the Netherlands in which two identical commercial vehicles equipped with ACC systems were driven simultaneously. The first vehicle was used to create a pre-specified speed profile by adapting the ACC system settings manually, whereas the second vehicle followed the lead vehicle when the ACC system was engaged to test its actual performance. The main findings indicate that the different system settings affect the car-following indicators, and system response times were found to be comparable to human response times. The eco mode was found to affect some of the car-following indicators, and it does not deteriorate safety below the safety level of driving with short headway setting in drive mode.
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- 2022
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6. Altered neurodevelopmental DNA methylation status after fetal growth restriction with brain-sparing
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Richter, Anne E., Bekkering-Bauer, Iris, Verkaik-Schakel, Rikst Nynke, Leeuwerke, Mariëtte, Tanis, Jozien C., Bilardo, Caterina M., Kooi, Elisabeth M. W., Scherjon, Sicco A., Bos, Arend F., and Plösch, Torsten
- Abstract
AbstractIt is under debate how preferential perfusion of the brain (brain-sparing) in fetal growth restriction (FGR) relates to long-term neurodevelopmental outcome. Epigenetic modification of neurotrophic genes by altered fetal oxygenation may be involved. To explore this theory, we performed a follow-up study of 21 FGR children, in whom we prospectively measured the prenatal cerebroplacental ratio (CPR) with Doppler sonography. At 4 years of age, we tested their neurodevelopmental outcome using the Wechsler Preschool and Primary Scale of Intelligence, the Child Behavior Checklist, and the Behavior Rating Inventory of Executive Function. In addition, we collected their buccal DNA to determine the methylation status at predefined genetic regions within the genes hypoxia-inducible factor-1 alpha (HIF1A), vascular endothelial growth factor A (VEGFA), erythropoietin (EPO), EPO-receptor (EPOR), brain-derived neurotrophic factor (BDNF), and neurotrophic tyrosine kinase, receptor, type 2 (NTRK2) by pyrosequencing. We found that FGR children with fetal brain-sparing (CPR <1, n= 8) demonstrated a trend (0.05 < p< 0.1) toward hypermethylation of HIF1Aand VEGFAat their hypoxia-response element (HRE) compared with FGR children without fetal brain-sparing. Moreover, in cases with fetal brain-sparing, we observed statistically significant hypermethylation at a binding site for cyclic adenosine monophophate response element binding protein (CREB) of BDNFpromoter exon 4 and hypomethylation at an HRE located within the NTRK2promoter (both p<0.05). Hypermethylation of VEGFAwas associated with a poorer Performance Intelligence Quotient, while hypermethylation of BDNFwas associated with better inhibitory self-control (both p<0.05). These results led us to formulate the hypothesis that early oxygen-dependent epigenetic alterations due to hemodynamic alterations in FGR may be associated with altered neurodevelopmental outcome in later life. We recommend further studies to test this hypothesis.
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- 2022
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7. Perinatal exposure to fluoxetine and maternal adversity affect myelin-related gene expression and epigenetic regulation in the corticolimbic circuit of juvenile rats
- Author
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Ramsteijn, Anouschka S., Verkaik-Schakel, Rikst Nynke, Houwing, Danielle J., Plösch, Torsten, and Olivier, Jocelien D. A.
- Abstract
Many pregnant women experience symptoms of depression, and are often treated with selective serotonin reuptake inhibitor (SSRI) antidepressants, such as fluoxetine. In utero exposure to SSRIs and maternal depressive symptoms is associated with sex-specific effects on the brain and behavior. However, knowledge about the neurobiological mechanisms underlying these sex differences is limited. In addition, most animal research into developmental SSRI exposure neglects the influence of maternal adversity. Therefore, we used a rat model relevant to depression to investigate the molecular effects of perinatal fluoxetine exposure in male and female juvenile offspring. We performed RNA sequencing and targeted DNA methylation analyses on the prefrontal cortex and basolateral amygdala; key regions of the corticolimbic circuit. Perinatal fluoxetine enhanced myelin-related gene expression in the prefrontal cortex, while inhibiting it in the basolateral amygdala. SSRI exposure and maternal adversity interacted to affect expression of genes such as myelin-associated glycoprotein (Mag) and myelin basic protein (Mbp). We speculate that altered myelination reflects altered brain maturation. In addition, these effects are stronger in males than in females, resembling known behavioral outcomes. Finally, Magand Mbpexpression correlated with DNA methylation, highlighting epigenetic regulation as a potential mechanism for developmental fluoxetine-induced changes in myelination.
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- 2022
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8. Narrow stack emissions: Errors in flow rate measurement due to disturbances and swirl
- Author
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Knotek, Stanislav, Workamp, Marcel, Geršl, Jan, and Schakel, Menne D.
- Abstract
ABSTRACTEuropean legislation continues to drive down emission limit values, making the emission measurement of narrow stacks of increasing importance. However, the applicable standards (EN ISO 16911–1 and EN 15259) are poorly validated for narrow stacks, and the effect of flow disturbances on the described methods are largely unknown. In this article, measurement errors are investigated in narrow stacks with flow disturbances and swirl, both experimentally and through computational fluid dynamics (CFD) simulations. The results indicate that measurement errors due to misalignment of the flow with typical measuring probes (pitot tubes) are small compared to errors resulting from the positioning of these probes in the measurement plane. Errors up to 15% are reported using the standardized methods, while the measurement error is both smaller and more predictable when using additional measurement points.Implications: Current international standards provide methods to measure emissions from industrial stacks. With increasingly small emission limit values, the accuracy of these measurements is becoming considerably more important. The data from this study can be used to inform revisions of these standards, in particular with respect to flow disturbances in narrow stacks, and can help law- and policy-makers to obtain insight into the uncertainties of emission measurements in these specific situations.
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- 2021
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9. In uterosFlt-1 exposure differentially affects gene expression patterns in fetal liver
- Author
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Stojanovska, V., Holwerda, K. M., van der Graaf, A. M., Verkaik-Schakel, R. N., Boekschoten, M. V., Faas, M. M., Scherjon, S. A., and Plösch, T.
- Abstract
AbstractThe soluble fms-like tyrosine kinase factor 1 (sFlt-1) is a major contributor to antiangiogenesis during preeclampsia. However, little is known about the effects of sFlt-1 on fetal health. In this study we aim to evaluate the effects of the sFlt-1 concentration during pregnancy on fetal liver physiology. We used adenoviral gene delivery in Sprague-Dawley dams (seven females, 10 weeks old) during mid-gestation (gestational day 8) with adenovirus overexpressing sFlt-1, and age-matched controls (six females, 10 weeks old) with empty adenoviral virus in order to quantify the sFlt-1 concentrations in pregnant dams. Dams exposed to adenoviral sFlt-1 delivery were subdivided into a low (n=4) and high sFlt-1 (n=3) group based on host response to the virus. One-way analysis of variance showed that fetuses (five per dam) exposed to high sFlt-1 concentrations in uteroshow fetal growth restriction (1.84±0.043 g high sFlt-1 v.2.32±0.036 g control; mean (M)±s.e.m.; P<0.001), without hypertension or proteinuria in the dams. In continuation, the microarray analysis of the fetal liver of the high sFlt-1 group showed significant enrichment of key genes for fatty acid metabolism and Ppara targets. In addition, using pyrosequencing, we found that the Ppara enrichment in the high sFlt-1 group is accompanied by decreased methylation of its promoter (1.89±0.097 mean % methylation in high sFlt-1 v.2.26±0.095 mean % methylation in control, M±s.e.m., P<0.02). Our data show that high sFlt-1 concentrations during pregnancy have detrimental effects on the fatty acid metabolism genes and the Ppara targets in the fetal liver.
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- 2019
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10. Measuring and theorizing regional governance
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Eaton, Kent, Faguet, Jean-Paul, Harbers, Imke, Schakel, Arjan H., Hooghe, Liesbet, Marks, Gary, Niedzwiecki, Sara, Osterkatz, Sandra Chapman, and Shair-Rosenfield, Sarah
- Abstract
ABSTRACTThis symposium Regional Authority and the Postfunctionalist Theory of Governance engages two recent books on regional governance. The first sets out a measure of regional authority for 81 countries in North America, Europe, Latin America, Asia and the Pacific between 1950 and 2010. The second theorizes how regional governance is shaped by functional and communal pressures. These pressures are detected in many historical episodes of jurisdictional reform. These books seek to pin them down empirically. Community and efficiency appear to have tangible and contrasting effects that explain how jurisdictions are designed, why regional governance has become differentiated and how multilevel governance has deepened over the past several decades. The symposium consists of contributions by Kent Eaton, Jean-Paul Faguet and Imke Harbers followed by a response from the authors: Liesbet Hooghe, Gary Marks, Arjan H. Schakel, Sara Niedzwiecki, Sandra Chapman Osterkatz and Sarah Shair-Rosenfield, Measuring Regional Authority: A Postfunctionalist Theory of Governance, Vol. I. Oxford: Oxford University Press, 2016; and Liesbet Hooghe and Gary Marks, with Arjan H. Schakel, Sara Niedzwiecki, Sandra Chapman Osterkatz and Sarah Shair-Rosenfield, Community, Scale, and Regional Governance: A Postfunctionalist Theory of Governance, Vol. II. Oxford: Oxford University Press, 2016.
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- 2019
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11. New indicator for comparing the energy performance of CO2 utilization concepts.
- Author
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Schakel, Wouter, Fernández-Dacosta, Cora, van der Spek, Mijndert, and Ramírez, Andrea
- Subjects
CARBON dioxide ,GREENHOUSE gases ,ENERGY consumption - Abstract
CO 2 utilization is increasingly considered a greenhouse gas abatement strategy alternatively to CO 2 storage. Existing indicators that assess the performance of CO 2 utilization options often provide an incomplete perspective and are unsuitable to compare different utilization options with different functionality (e.g. plastics and fuels). This study introduces a new performance indicator for CO 2 utilization options: Specific Primary Energy Consumption per unit of Fossil feedstock Replaced (SPECFER). This indicator, expressed in MJ/MJ, provides a proxy for the energy efficiency of which CO 2 conversion options can replace fossil feedstock required in conventional processes. Three CO 2 utilization case studies (CO 2 based methanol, polyols and dimethyl ether) are used to show the application and effectiveness of the SPECFER indicator. Among the case studies, only CO 2 conversion into polyol appears particularly efficient (SPECFER of 0.05 MJ/MJ), while the other options are not (SPECFER of > 1 MJ/MJ). The paper shows that the SPECFER indicator adds key insights compared to conventional indicators to the effectiveness of CO 2 utilization options and is a promising indicator complementary to CO 2 emissions reduction or life cycle greenhouse gas reduction potential. The SPECFER thus improves the understanding of the performance of CO 2 utilization and enables the possibility to distinctly compare different CO 2 converting utilization technologies. [ABSTRACT FROM AUTHOR]
- Published
- 2017
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12. Impact of Fuel Selection on Techno-environmental Performance of Post-combustion Calcium Looping Process Applied to a Cement Plant.
- Author
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Schakel, Wouter, Orregioni, Gabriel, Strømman, Anders, and Ramirez, Andrea
- Abstract
Calcium looping CO 2 capture is a promising technology to reduce CO 2 emissions from cement production. Coal is generally considered the fuel used to drive the calcium looping process as coal is already used as feedstock for cement production. This study assesses the impact of different fuels (coal, natural gas and woody biomass) on the technological and environmental performance of post-combustion calcium looping at a cement plant in North-western Europe. Process modelling is used to determine the impact of the different fuels on the mass and energy balance of the process. Life cycle assessment is carried out to evaluate the environmental performance of the different systems. Results indicate that firing natural gas or biomass instead of coal in an add-on calcium looping process can improve the efficiency of the process, as it decreases the fuel, limestone and electricity consumption. Consequently, while coal fired calcium looping can reduce life cycle climate change potential by 92%, the use of natural gas or biomass can make the process carbon neutral (reduction of 100%) or negative (-169%), respectively. Further research is required to complete the environmental perspective of using alternative fuels, but these results already illustrate a potential low-hanging fruit to improve the environmental performance of post combustion calcium looping in the cement industry. [ABSTRACT FROM AUTHOR]
- Published
- 2017
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13. Feasibility Assessment of CO2 Capture Retrofitted to an Existing Cement Plant: Post-combustion vs. Oxy-fuel Combustion Technology.
- Author
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Gerbelová, Hana, van der Spek, Mijndert, and Schakel, Wouter
- Abstract
This research presents a preliminary techno-economic evaluation of CO 2 capture integrated with a cement plant. Two capture technologies are evaluated, monoethanolamine (MEA) post-combustion CO 2 capture and oxy-fuel combustion. Both are considered potential technologies that could contribute to reduction of CO 2 emissions in the cement industry. The study compares these two technologies in terms of technical performance, investment costs, and operational costs. The case study is applied to the one of the largest cement plants in Portugal, Alhandra. The results show that the amount of CO 2 avoided using the post-combustion MEA technology is lower due to additional emissions from reboiler steam production. Moreover, the total capital investment of the post-combustion CO 2 capture system is estimated at 260 M€ 2014 and the annual operation and maintenance costs of around 43 M€ 2014 ; whereas the oxy-fuel combustion CO 2 capture requires a capital investment of about 217 M€ 2014 and 37 M€ 2014 annually for operation and maintenance. This indicates that the oxy-fuel CO 2 capture technology may be a better choice in terms of costs. However, this technology implies higher technical uncertainties concerning integration with the cement plant. [ABSTRACT FROM AUTHOR]
- Published
- 2017
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14. Ideological congruence and socio-economic inequality
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Schakel, Wouter and Hakhverdian, Armen
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This study examines whether or not political representation in the Netherlands is biased toward the rich and higher educated by comparing the political orientations of members of parliament to those of the electorate. The analyses reveal stark differences in the representation of different socio-economic groups. The political views of elected national representatives are far more similar to those of rich, higher educated citizens than to those with less income and education. Moreover, a longitudinal analysis reveals that inequalities in political representation have actually grown in recent years. We also show that the use of measures of ideological self-identification might to lead to highly misleading results regarding the nature of political representation as opposed to the use of issue items. We conclude that, despite a highly proportional electoral system, the views which are represented in the Dutch lower house of parliament contain major distortions of the views of the broader electorate.
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- 2018
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15. Assessing the techno-environmental performance of CO2 utilization via dry reforming of methane for the production of dimethyl ether.
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Schakel, Wouter, Ramírez, Andrea, Oreggioni, Gabriel, Singh, Bhawna, and Strømman, Anders
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CARBON dioxide ,METHANE ,METHYL ether - Abstract
CO 2 utilization is gaining attention as a greenhouse gas abatement strategy complementary to CO 2 storage. This study explores the techno-environmental performance of CO 2 utilization trough dry reforming of methane into syngas for the production of dimethyl ether (DME). The CO 2 source is a hydrogen production unit at a refinery, where solvent based CO 2 capture is applied. Aspen+ modelling and hybrid life cycle assessment (LCA) is used to assess the techno-environmental performance of this utilization option compared to a reference case without CO 2 capture and a case with CO 2 capture and storage. Results of the technical assessment show that although 94% of the captured CO 2 can be utilised for DME production, only 9% of CO 2 is avoided in the entire process as a result of direct CO 2 formation during DME synthesis and the combustion of syngas to provide the heat demanded by the dry reforming process. Besides, a substantial amount of electricity is required for syngas compression. Consequently, the LCA results indicate that climate change potential (CCP) is reduced by 8% while it is 37% higher than CCP when CO 2 is stored and DME is produced conventionally. Sensitivity analyses are performed on various process conditions. Overall, this study indicates that this utilization route lowers the CCP although the reduction is limited compared to CCS. While the techno-environmental analysis is a useful tool to gain better insights in the performance of CO 2 utilization options, the complex environmental trade-offs make it difficult to draw robust conclusions on the performance. [ABSTRACT FROM AUTHOR]
- Published
- 2016
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16. iPr2N-PFe(CO)4 in Olefinic Solvents: A Reservoir of a Transient Phosphinidene Complex Capable of Substrate Hopping.
- Author
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Wit, Jan B. M., de Jong, G. Bas, Schakel, Marius, Lutz, Martin, Ehlers, Andreas W., Slootweg, J. Chris, and Lammertsma, Koop
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- 2016
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17. New indicator for comparing the energy performance of CO2utilization concepts
- Author
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Schakel, Wouter, Fernández-Dacosta, Cora, van der Spek, Mijndert, and Ramírez, Andrea
- Abstract
•A new performance indicator for CO2utilization is introduced.•Indicator is a proxy for the energy efficiency of CO2utilization options.•Three example case studies highlight the applicability of the indicator.•Indicator enables comparison of CO2utilization options with different functionality.
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- 2017
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18. The fetal programming effect of prenatal smoking on Igf1rand Igf1methylation is organ- and sex-specific
- Author
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Meyer, Karolin F., Verkaik-Schakel, Rikst Nynke, Timens, Wim, Kobzik, Lester, Plösch, Torsten, and Hylkema, Machteld N.
- Abstract
ABSTRACTThe impact of prenatal smoke exposure (PSE) on DNA methylation has been demonstrated in blood samples from children of smoking mothers, but evidence for sex-dependent smoke-induced effects is limited. As the identified differentially methylated genes can be associated with developmental processes, and insulin-like growth factors (IGFs) play a critical role in prenatal tissue growth, we hypothesized that PSE induces fetal programming of Igf1rand Igf1.Using a mouse model of smoking during pregnancy, we show that PSE alters promoter methylation of Igf1rand Igf1and deregulates their gene expression in lung and liver of fetal (E17.5) and neonatal (D3) mouse offspring. By further comparing female versus male, lung versus liver, or fetal versus neonatal time point, our results demonstrate that CpG site-specific aberrant methylation patterns sex-dependently vary per organ and time point. Moreover, PSE reduces gene expression of Igf1rand Igf1, dependent on organ, sex, and offspring's age. Our results indicate that PSE may be a source of organ-specific rather than general systemic fetal programming. This is exemplified here by gene promoter methylation and mRNA levels of Igf1rand Igf1,together with a sex- and organ-specific naturally established correlation of both parameters that is affected by prenatal smoke exposure. Moreover, the comparison of fetuses with neonates suggests a CpG site-dependent reversibility/persistence of PSE-induced differential methylation patterns.
- Published
- 2017
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19. Serum Concentration of Anti-TNF Antibodies, Adverse Effects and Quality of Life in Patients with Inflammatory Bowel Disease in Remission on Maintenance Treatment.
- Author
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Brandse, Johannan F., Vos, Laura M. C., Jansen, Jeroen, Schakel, Toos, Ponsioen, Cyriel I. J., van den Brink, Gijs R., D'Haens, Geert R., and Löwenberg, Mark
- Abstract
Background and aims: High serum concentrations of infliximab [IFX] and adalimumab [ADA] may be associated with adverse effects in patients with inflammatory bowel disease [IBD]. We aimed to investigate whether high anti-tumour necrosis factor [TNF] trough levels [TLs] were associated with toxicity and impaired quality of life [QoL]. Methods: We conducted a prospective cohort study in IBD patients in clinical and biochemical remission on IFX or ADA maintenance therapy. Trough serum concentrations and antidrug antibodies were measured in addition to biochemical markers of inflammation in serum and stool to confirm quiescent disease. QoL was assessed using the Inflammatory Bowel Disease Questionnaire and 36-item short form]. Side effects such as fatigue and arthralgia were measured with a visual analogue score [VAS]. Skin toxicity was reported with a European Organization for Research and Treatment of Cancer-derived score. Results: In all, 252 IBD patients on maintenance anti-TNF therapy were screened, of whom 95 [73 with Crohn's disease, 22 with ulcerative colitis; 72 on IFX, 23 on ADA] were in clinical and biochemical remission and were included. Median TLs were 5.5 µg/ml and 6.6 µg/ml for IFX and ADA, respectively. Patients with anti-TNF TLs above median had lower IBDQ scores than patients with lower TLs [IBDQ 176 vs 187, p = 0.02], particularly regarding systemic symptoms and emotional status. A trend towards lower SF-36 and higher fatigue scores was observed in the higher anti-TNF TL group. Skin and arthralgia scores were not significantly different between the groups. Conclusions: IBD patients with higher anti-TNF serum concentrations had significantly lower disease-specific QoL. Fatigue, arthralgia, and skin lesions do not occur more often in these patients. These data are reassuring that high serum concentrations of anti-TNF antibodies are not toxic. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
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20. Exploring the potential impact of implementing carbon capture technologies in fossil fuel power plants on regional European water stress index levels.
- Author
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Schakel, Wouter, Pfister, Stephan, and Ramírez, Andrea
- Subjects
FOSSIL fuel power plants ,CARBON sequestration ,WATER chemistry ,COOLING - Abstract
Equipping power plants with carbon capture technology can affect cooling demand and water use. This study has explored the potential impact of large scale deployment of power plants with carbon capture technologies on future regional water stress in Europe. A database including 458 of European largest power plants with data on location, technology, age, fuel type, amount of electricity generation and cooling method has been developed. This data has been combined with literature data on water use rates and developed scenarios to calculate corresponding water use of these European power plants for 2030 and 2050 under different conditions, such as the penetration level of carbon capture technologies and installed technologies. Water stress methodology based on water withdrawal has been used to explore the impact of carbon capture and storage on future water stress levels. Our findings indicate that by 2030, no considerable increase in water stress is expected due to the instalment of carbon capture technologies. However, when assuming a high penetration level of carbon capture technologies, water stress in 2050 might substantially increase in many regions in Europe. The extent of the increase in water stress strongly depends on penetration level of carbon capture, installed power plant and cooling technologies and applied water stress methodology. When using water consumption to estimate water stress, the results do not indicate significant changes in water stress for the scenarios with carbon capture. Nevertheless, as water stress based on water withdrawal is currently the common method, the results of this study provide reasons for concern regarding the potential impact of carbon capture on future European water stress levels and indicate the need for future research to monitor and possibly prevent potential water stress increases from the instalment of carbon capture technologies. [ABSTRACT FROM AUTHOR]
- Published
- 2015
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21. Getting the Human Factor into Traffic Flow Models
- Author
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van Lint, Hans, Schakel, Wouter, Tamminga, Guus, Knoppers, Peter, and Verbraeck, Alexander
- Abstract
Automated driving may lead to much higher road capacities, combined with increased road safety, increased driver comfort, and lower costs. Although this vision may hold ground in the long run, first a transitional period will take place in which increasing percentages of vehicles with many levels of automation will drive on the world’s road networks. This transition poses a fundamental scientific challenge. The models used today to simulate and predict vehicular traffic are not valid to predict emergent properties of traffic flows under increasing amounts of vehicle automation. For example, there is no idea of how drivers of nonautomated vehicles will respond to other drivers reading their morning papers behind the steering wheel or the consequences of such interactions on traffic safety and capacity. In this paper, the authors do not propose a new behavioral theory with which the effects of increasing vehicle automation can be predicted. What the authors propose is an advanced open-source simulation framework, OpenTrafficSim, which makes it possible to extend microscopic models incrementally with explanatory mental models, such that new behavioral theories can be tested and shared within the community. Given the societal importance of predicting the effects on safety and efficiency of vehicle automation, the authors sincerely hope this paper will fuel the discussion on how both open-source and closed-source simulation software can be adapted and made ready for the next generation of traffic simulation models that are needed in the coming decades.
- Published
- 2016
- Full Text
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22. Assessing the techno-environmental performance of CO2utilization via dry reforming of methane for the production of dimethyl ether
- Author
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Schakel, Wouter, Oreggioni, Gabriel, Singh, Bhawna, Strømman, Anders, and Ramírez, Andrea
- Abstract
•Utilizing CO2into dimethyl ether improves techno-environmental performance.•Climate change potential reduction is limited compared to CO2capture and storage.•Environmental trade-offs of CCU more complex than those of CO2capture and storage.•Techno-environmental analysis improves insights in performance of CO2utilization options.
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- 2016
- Full Text
- View/download PDF
23. Getting the Human Factor into Traffic Flow Models: New Open-Source Design to Simulate Next Generation of Traffic Operations
- Author
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van Lint, Hans, Schakel, Wouter, Tamminga, Guus, Knoppers, Peter, and Verbraeck, Alexander
- Abstract
Automated driving may lead to much higher road capacities, combined with increased road safety, increased driver comfort, and lower costs. Although this vision may hold ground in the long run, first a transitional period will take place in which increasing percentages of vehicles with many levels of automation will drive on the world’s road networks. This transition poses a fundamental scientific challenge. The models used today to simulate and predict vehicular traffic are not valid to predict emergent properties of traffic flows under increasing amounts of vehicle automation. For example, there is no idea of how drivers of nonautomated vehicles will respond to other drivers reading their morning papers behind the steering wheel or the consequences of such interactions on traffic safety and capacity. In this paper, the authors do not propose a new behavioral theory with which the effects of increasing vehicle automation can be predicted. What the authors propose is an advanced open-source simulation framework, OpenTrafficSim, which makes it possible to extend microscopic models incrementally with explanatory mental models, such that new behavioral theories can be tested and shared within the community. Given the societal importance of predicting the effects on safety and efficiency of vehicle automation, the authors sincerely hope this paper will fuel the discussion on how both open-source and closed-source simulation software can be adapted and made ready for the next generation of traffic simulation models that are needed in the coming decades.
- Published
- 2016
- Full Text
- View/download PDF
24. Assessment of Implementing Carbon Capture Technologies in Fossil Fuel Power Plants on Regional European Water Stress Index Levels.
- Author
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Schakel, Wouter, Pfister, Stephan, and Ramírez, Andrea
- Abstract
Equipping power plants with carbon capture technologies increases the (cooling) water demand of these plants. This study explores the potential impact of such increase in water demand on the regional water scarcity in Europe. A database with key characteristics of 458 of the largest European power plants is developed and the water use of these power plants is estimated. The water use of the power plants are spatially linked to current water stress index levels. Several prospective scenarios are developed accounting for variations in the future configuration of Europe's electricity generation and different penetration rates of carbon capture technology. Regional water stress index levels are calculated to compare the potential impact of applying carbon capture technologies on the water stress. Preliminary results indicate that the increase of water use due to carbon capture technology is partly expected to be compensated by the deployment of more efficient energy conversion methods which require less cooling water. As such, no significant increase in water stress is expected in the short term (2030), as the carbon capture penetration level in European power plants is expected to be quite low. However, on the long term (2050), large scale instalment of carbon capture technologies in power plants might significantly increase the water stress throughout Europe. [ABSTRACT FROM AUTHOR]
- Published
- 2014
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25. Environmental Due Diligence of CO2 Capture and Utilization Technologies – Framework and application.
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Singh, Bhawna, Reijers, Rick, van der Spek, Mijndert W., Schakel, Wouter B., Skagestad, Ragnhild, Haugen, Hans Aksel, Ramirez, Andrea, Eldrup, Nils Henrik, Hertwich, Edgar G., and Strømman, Anders Hammer
- Abstract
This article presents an overview of an environmental due diligence framework developed as part of the EDDiCCUT project, and presents analysis and results from the first test case – MEA based CO 2 capture process. The framework draws upon well-established technical, economic and environmental assessment methods and integrates technical performance, uncertainties, cost estimation and life cycle inventory data to ensure consistency and enhance quality. Results show that for the modelled coal power plant of about 800 MW gross power output, the CO 2 capture system lowers the net efficiency by 10.4% efficiency points and results in a 68% increase in the cost of electricity. Environmental performance evaluated on a broad range of 24 impacts and emission categories indicates a 68% reduction in climate change warming potential with 20-90% increase in other impacts. By comparing the quality of the inventory data used for environmental assessment with the state-of-art data in available life cycle assessment literature, it is found that the due diligence analysis brings significant improvement in the quality of data for certain processes in the value chain. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
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26. Sustainability Assessment of the Large Implementation of Carbon Capture and Storage in OECD Europe.
- Author
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Ramírez, Andrea, Schakel, Wouter, Grytli, Tuva, and Wood, Richard
- Abstract
This paper shows the results of a sustainability assessment of deploying carbon capture and storage in European coal power plants in 2030, versus a scenario without CCS. The assessment examines potential impacts in five categories: impacts on human health, impacts on the natural environment, impacts on exhaustive resources, impacts on prosperity and impacts on social well-being. The analysis is undertaken in a prospective framework for the year 2030 under the economic scenarios which are based on the Blue map scenario of the IEA Energy Technology Perspectives. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
27. A general framework for calibrating and comparing car-following models
- Author
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van Hinsbergen, C.P.I.J., Schakel, W.J., Knoop, V.L., van Lint, J.W.C., and Hoogendoorn, S.P.
- Abstract
Recent research has shown that there exists large heterogeneity in car-following behaviour such that different car-following models best describe different drivers' behaviour. A literature review reveals that current approaches to calibrate and compare different models for one driver do not take the complexity of the models into account or are only able to compare a specific set of models. This contribution applies Bayesian techniques to the calibration of car-following models. The Bayesian framework promotes models that fit the data well but punishes models with a high complexity, resulting in a measure called the evidence. This evidence quantifies how probable each model is to be the model that best describes the car-following behaviour of a single driver. It can be computed for any car-following model. When considered over multiple drivers, the evidences can be used to describe the heterogeneity of the driving population. In an experiment seven different car-following models are calibrated and compared using a data set that was collected with a helicopter. The results indicate that multi-leader models better describe the car-following models even if their higher complexity is accounted for, and that for the description of microscopic driving behaviour the reaction time is essential; models without a reaction time perform significantly worse.
- Published
- 2015
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28. Nationalisation of regional elections in Central and Eastern Europe
- Author
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Schakel, Arjan H.
- Abstract
Territory is a salient issue in post-communist countries in Europe, yet subnational elections have received surprisingly little attention. This article analyses congruence between national and regional elections in Croatia, the Czech Republic, Hungary, Poland, Romania and the Slovak Republic held between 1993 and 2010. The findings suggest that election incongruence can be partly explained by approaches which work well in the West European context – territorial cleavages, regional authority and the second-order election model – but in order to fully grasp regional election outcomes in post-communist countries one also needs to take into account electoral alliance strategies and party supply change.
- Published
- 2015
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29. Seismoelectric interface response: Experimental results and forward model.
- Author
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Schakel, M. D., Smeulders, D. M. J., Slob, E. C., and Heller, H. K. J.
- Subjects
ELECTRIC fields ,PETROLEUM prospecting ,GEOPHYSICS ,ELECTRIC waves ,ELECTROMAGNETIC waves - Abstract
Understanding the seismoelectric interface response is important for developing seismoelectric field methods for oil exploration and environmental/engineering geophysics. The existing seismoelectric theory has never been validated systematically by controlled experiments. We have designed and developed an experimental setup in which acoustic-toelectromagnetic wave conversions at interfaces are measured. An acoustic source emits a pressure wave that impinges upon a porous sample. The reflected electric-wave potential is recorded by a wire electrode. We have also developed a full-waveform electrokinetic theoretical model based on the Sommerfeld approach and have compared it with measurements at positions perpendicular and parallel to the fluid/porous-medium interface. We performed experiments at several salinities. For 10
-3 and 10-2 M sodium chloride (NaCl) solutions, both waveforms and amplitudes agree. For 10-4 M NaCl, however, amplitude deviations occur. We found that a single amplitude field scaling factor describes these discrepancies. We also checked the repeatability of experiments. The amplitudes are constant for the duration of an experiment (1-4 hours) but decrease on longer time scales (~24 hours). However, the waveforms and spatial amplitude pattern of the electric wavefield are preserved over time. Our results validate electrokinetic theory for the seismic-to-electromagnetic-wave conversion at interfaces for subsurface exploration purposes. [ABSTRACT FROM AUTHOR]- Published
- 2011
- Full Text
- View/download PDF
30. Worms exploring geometrical features of phase transitions.
- Author
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Janke, Wolfhard, Neuhaus, Thomas, and Schakel, Adriaan M.J.
- Subjects
PHASE transitions ,STATISTICAL physics ,RANDOM graphs ,MONTE Carlo method ,ALGORITHMS ,SELF-avoiding walks (Mathematics) ,PERCOLATION theory - Abstract
Abstract: The loop-gas approach to statistical physics provides an alternative, geometrical description of phase transitions in terms of line-like objects. The resulting statistical random-graph ensemble composed of loops and (open) chains can be e_ciently generated by Monte Carlo simulations using the so-called “worm” update algorithm. Concepts from percolation theory and the theory of self-avoiding random walks are used to derive estimators of physical observables that utilize the nature of the worm algorithm. The fractal structure of random loops and chains as well as their scaling properties encode the critical behavior of the statistical system. The general approach is illustrated for the hightemperature series expansion of the Ising model, or O(1) loop model, on a honeycomb lattice, with its known exact results as valuable benchmarks. [Copyright &y& Elsevier]
- Published
- 2011
- Full Text
- View/download PDF
31. Botulinum toxin—Beyond wrinkles.
- Author
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Schakel, Andrew L.
- Subjects
BOTULINUM toxin ,SKIN aging - Abstract
Botulinum neurotoxin is produced by the bacterium, Clostridium botulinum. The neurotoxin inhibits acetylcholine at the neuromuscular junction, thus interfering with overall muscular contraction. Botulinum neurotoxin is commonly used for the following medical conditions: cervical dystonia, upper limb spasticity, blepharospasm, strabismus, and hyperhydrosis. However, the use of botulinum neurotoxin was recently approved for the prophylaxis of headaches in adults with chronic migraines. The proposed mechanism of botulinum neurotoxin is no longer solely limited to the inhibition of acetylcholine. There are new mechanisms emerging that involve inhibition of proinflammatory agents and neuropeptides involved in chronic pain. Consequently, there is a disruption of the overall sensory feedback loop involved in chronic pain, thus decreasing peripheral and central sensitization. [Copyright &y& Elsevier]
- Published
- 2011
- Full Text
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32. Phospha-Scorpionate Complexes by Click Chemistry using Phenyl Azide and Ethynylphosphine Oxides.
- Author
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Sander G. A. van Assema, Cornelis G. J. Tazelaar, G. Bas de Jong, Jan H. van Maarseveen, Marius Schakel, Martin Lutz, Anthony L. Spek, J. Chris Slootweg, and Koop Lammertsma
- Published
- 2008
- Full Text
- View/download PDF
33. Synthesis, Structures, and Strain Energies of Dispirophosphiranes. Comparisons with Dispirocyclopropanes.
- Author
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Vlaar, Mark J.M., Lor, Maarten H., Ehlers, Andreas W., Schakel, Marius, Lutz, Martin, Spek, Anthony L., and Lammertsma, Koop
- Published
- 2002
- Full Text
- View/download PDF
34. Hidden Images of Christ in the Fiction of C. S. Lewis
- Author
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Schakel, Peter J.
- Published
- 2013
35. Integrated Lane Change Model with Relaxation and Synchronization
- Author
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Schakel, Wouter, Knoop, Victor, and van Arem, Bart
- Abstract
A proposed lane change model can be integrated with a car-following model to form a complete microscopic driver model. The model resembles traffic better at a macroscopic level, especially regarding the amount of traffic volume per lane, the traffic speeds in different lanes, and the onset of congestion. In a new approach, lane change incentives are combined for determining a lane change desire. Included incentives are to follow a route, to gain speed, and to keep right. Classification of lane changes is based on behavior that depends on the level of lane change desire. Integration with a car-following model is achieved by influencing car-following behavior for relaxation and synchronization, that is, following vehicles in adjacent lanes. Other improvements of the model are trade-offs between lane change incentives and the use of anticipation speed for the speed gain incentive. Although all these effects are captured, the lane change model has only seven parameters. Loop detector data were used to validate and calibrate the model, and an accurate representation of lane distribution and the onset of congestion was shown.
- Published
- 2012
- Full Text
- View/download PDF
36. Integrated Lane Change Model with Relaxation and Synchronization
- Author
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Schakel, Wouter J., Knoop, Victor L., and van Arem, Bart
- Abstract
A proposed lane change model can be integrated with a car-following model to form a complete microscopic driver model. The model resembles traffic better at a macroscopic level, especially regarding the amount of traffic volume per lane, the traffic speeds in different lanes, and the onset of congestion. In a new approach, lane change incentives are combined for determining a lane change desire. Included incentives are to follow a route, to gain speed, and to keep right. Classification of lane changes is based on behavior that depends on the level of lane change desire. Integration with a car-following model is achieved by influencing car-following behavior for relaxation and synchronization, that is, following vehicles in adjacent lanes. Other improvements of the model are trade-offs between lane change incentives and the use of anticipation speed for the speed gain incentive. Although all these effects are captured, the lane change model has only seven parameters. Loop detector data were used to validate and calibrate the model, and an accurate representation of lane distribution and the onset of congestion was shown.
- Published
- 2012
- Full Text
- View/download PDF
37. Human neutrophils interact with both 6-sulfo LacNAc+ DC and NK cells to amplify NK-derived IFNγ: role of CD18, ICAM-1, and ICAM-3
- Author
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Costantini, Claudio, Calzetti, Federica, Perbellini, Omar, Micheletti, Alessandra, Scarponi, Claudia, Lonardi, Silvia, Pelletier, Martin, Schakel, Knut, Pizzolo, Giovanni, Facchetti, Fabio, Vermi, William, Albanesi, Cristina, and Cassatella, Marco A.
- Abstract
The role of neutrophils as key players in the regulation of innate and adaptive immune responses is increasingly being recognized. We report that human neutrophils establish a network with both natural killer (NK) cells and 6-sulfo LacNAc+ dendritic cells (slanDCs), which ultimately serves to up-regulate NK-derived interferonγ (IFNγ). This network involves direct reciprocal interactions and positive amplification loops mediated by cell-derived cytokines. Accordingly, we show that after lipopolysaccharide + interleukin-2 (IL-2) or IL-15/IL-18 stimulation, neutrophils directly interact with and potentiate the activity of both slanDCs and NK cells. On the one hand, neutrophils augment the release of IL-12p70 by slanDCs via a CD18/ intercellular adhesion molecule-1 (ICAM-1) interaction that stimulates activated NK cells to produce IFNγ. IFNγ further potentiates the interaction between neutrophils and slanDCs and the release of slanDC-derived IL-12p70, thus creating a positive feedback loop. On the other hand, neutrophils directly costimulate NK cells via CD18/ICAM-3, leading to the production of IFNγ. Colocalization of neutrophils, NK cells, and slanDCs, as well as of IL-12p70 and IFNγ, in inflamed tissues of Crohn disease and psoriasis provides strong evidence for a novel cellular and cytokine cooperation within the innate immune system in which neutrophils act as amplifiers of NK cell/slanDC-mediated responses.
- Published
- 2011
- Full Text
- View/download PDF
38. Human neutrophils interact with both 6-sulfo LacNAc+DC and NK cells to amplify NK-derived IFNγ: role of CD18, ICAM-1, and ICAM-3
- Author
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Costantini, Claudio, Calzetti, Federica, Perbellini, Omar, Micheletti, Alessandra, Scarponi, Claudia, Lonardi, Silvia, Pelletier, Martin, Schakel, Knut, Pizzolo, Giovanni, Facchetti, Fabio, Vermi, William, Albanesi, Cristina, and Cassatella, Marco A.
- Abstract
The role of neutrophils as key players in the regulation of innate and adaptive immune responses is increasingly being recognized. We report that human neutrophils establish a network with both natural killer (NK) cells and 6-sulfo LacNAc+dendritic cells (slanDCs), which ultimately serves to up-regulate NK-derived interferonγ (IFNγ). This network involves direct reciprocal interactions and positive amplification loops mediated by cell-derived cytokines. Accordingly, we show that after lipopolysaccharide + interleukin-2 (IL-2) or IL-15/IL-18 stimulation, neutrophils directly interact with and potentiate the activity of both slanDCs and NK cells. On the one hand, neutrophils augment the release of IL-12p70 by slanDCs via a CD18/ intercellular adhesion molecule-1 (ICAM-1) interaction that stimulates activated NK cells to produce IFNγ. IFNγ further potentiates the interaction between neutrophils and slanDCs and the release of slanDC-derived IL-12p70, thus creating a positive feedback loop. On the other hand, neutrophils directly costimulate NK cells via CD18/ICAM-3, leading to the production of IFNγ. Colocalization of neutrophils, NK cells, and slanDCs, as well as of IL-12p70 and IFNγ, in inflamed tissues of Crohn disease and psoriasis provides strong evidence for a novel cellular and cytokine cooperation within the innate immune system in which neutrophils act as amplifiers of NK cell/slanDC-mediated responses.
- Published
- 2011
- Full Text
- View/download PDF
39. 821 Elektronisch Netwerken Doe Je Samen
- Author
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Schakel, L.
- Abstract
Samenvatting: Elektronische netwerken in de zorg winnen aan belang. Zorgaanbieders kunnen via uitwisseling van informatie via een elektronisch netwerk de zorgverlening aan hun patiënten kwalitatief beter, efficiënter en veiliger doen verlopen. Ook zorgaanbieders die niet vanaf de oprichting van een netwerk zijn aangesloten, moeten in een later stadium alsnog onder voorwaarden kunnen aansluiten. In de praktijk blijkt deze toetreding niet altijd soepel te verlopen. Zowel de Nederlandse Mededingingsautoriteit (NMa) als de Nederlandse Zorgautoriteit (NZa) heeft aangegeven hoe zorgaanbieders die deelnemen aan een elektronisch netwerk moeten omgaan met zorgaanbieders die wensen toe te treden: het moet transparant zijn hoe een zorgaanbieder tot het netwerk kan toetreden en de voorwaarden voor toetreding moeten redelijk, objectief en niet discriminerend zijn. De regeling die de NZa hier in december 2009 voor heeft vastgesteld, moet ervoor zorgen dat toetreding in de praktijk vergemakkelijkt wordt. Dit artikel schetst de bredere context van deze voorwaarden aan elektronische netwerken en bespreekt wat toetreders van deelnemers aan een netwerk mogen verwachten.
- Published
- 2010
- Full Text
- View/download PDF
40. Phosphinidene Addition to Conjugated Allenes
- Author
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Bertini, Federica, Wit, Jan B.M., Ünal, Murat, deKanter, Franciscus J.J., Schakel, Marius, Slootweg, J. Chris, Ehlers, AndreasW., Nijbacker, Tom, Komen, Corine M.D., Lutz, Martin, Spek, AnthonyL., and Lammertsma, Koop
- Abstract
Generating the transient electrophilic tungsten pentacarbonylphenylphosphinidene complex PhPWCO5in the presence of 2,7dimethylocta2,3,5,6tetraene leads to the formation of a 3,4disubstituted phosphole or a complexed phospholene, depending on the reaction conditions. The formation of the phospholene results from the reaction of PhPWCO5with the diallene, while the formation of the phosphole arises from reaction with 3,4diisopropylidenecyclobutene, which is formed in situfrom the isomerization of the conjugated allene.
- Published
- 2009
- Full Text
- View/download PDF
41. Video‐rate scanning probe control challenges: setting the stage for a microscopy revolution
- Author
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Rost, M. J., van Baarle, G. J. C., Katan, A. J., van Spengen, W. M., Schakel, P., van Loo, W. A., Oosterkamp, T. H., and Frenken, J. W. M.
- Abstract
Scanning probe microscopy is at the verge of revolutionizing microscopy once again. Video‐rate scanning tunneling microscope (STM) and video‐rate atomic force microscope (AFM) technology will enable the direct observation of many dynamic processes that are impossible to observe today, such as atom or molecule diffusion, real time film growth, or catalytic reactions. In this paper we discuss the critical aspects that have to be taken into account when working on increasing the imaging speed of scanning probe microscopes. We highlight the state‐of‐the‐art developments in the control of the piezoelectric scanning elements and describe the latest innovations regarding the design and construction of the whole mechanical loop including new scanner geometries. We identify critical aspects for which no obvious solution exists and aspects where advanced control engineering can help, like piezo non‐linearities, the acceleration limit and the challenging technical requirements for the preamplifiers that are needed for measuring a tunneling current. Finally, we provide an overview of a number of new directions that are being pursued to solve the problems currently encountered in scanning probe technology. Copyright © 2009 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society
- Published
- 2009
- Full Text
- View/download PDF
42. Fused Tricyclic Phosphiranes—Analysis of Phosphorus Chemical Shieldings
- Author
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Couzijn, Erik P. A., Ehlers, Andreas W., Slootweg, J. Chris, Schakel, Marius, Krill, Steffen, Lutz, Martin, Spek, Anthony L., and Lammertsma, Koop
- Abstract
1,2‐Addition of transient W(CO)5‐complexed phosphinidenes exoto hexamethyl Dewar benzene affords the novel 3‐phosphatricyclo[3.2.0.02,4]hept‐6‐ene complexes. The fused tricyclic phosphiranes are obtained as both the Zand the thermally less stable Eisomers, the 31P NMR chemical shifts of which differ by about 60 ppm. A computational investigation shows that the phosphorus pyramidalization and the presence of the γ double bond are responsible for this effect. The semiquantitative results contribute to a more systematic understanding of the structural influences on 31P chemical shieldings. The congested double bond of the Zisomer can be epoxidized with m‐chloroperbenzoic acid (MCPBA) to afford a fused tetracyclic P,O bis‐adduct.
- Published
- 2008
- Full Text
- View/download PDF
43. Acetylene-Substituted Phosphane Oxides: Building Blocks for Macrocycles
- Author
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van Assema, Sander G. A., de Jong, G. Bas, Ehlers, Andreas W., de Kanter, Frans J. J., Schakel, Marius, Spek, Anthony L., Lutz, Martin, and Lammertsma, Koop
- Abstract
Phosphorus-based macrocycles with acetylenic scaffolds have been built from acetylene-substituted phosphane oxides that were formed from diisopropylphosphoramidic dibromide (3) and an acetylenic Grignard reagent. The four- and six-edged macrocycles 15 and 16, in which the iPr2NP(O) units are connected through 1,3-butadiyne rods, were obtained from the monosilylated derivative of iPr2NP(O)(C2H)2 (7) by multiple acetylene coupling reactions under oxidative Hay conditions. Reaction of iPr2NP(O)(Br)2 (3) with lithiated 1,2-diethynylbenzene gave a mixture of cis and trans monocyclic bis(phosphane oxide) 18. An X-ray crystal structure determination of the trans isomer shows the ring structure to adopt a puckered form.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
- Published
- 2007
- Full Text
- View/download PDF
44. Aanmerkelijke Marktmacht (Amm) In De Zorg
- Author
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Schakel, L.
- Abstract
Samenvatting: Sinds de inwerkingtreding van de Wet marktordening gezondheidszorg (Wmg) op 1 oktober 2006 heeft de Nederlandse Zorgautoriteit (NZa) de bevoegdheid om het gedrag van een zorgaanbieder of zorgverzekeraar die over ‘aanmerkelijke marktmacht’ (amm) beschikt te disciplineren door het opleggen van passende verplichtingen. Recent heeft de NZa een consultatiedocument ‘Aanmerkelijke marktmacht (amm) in de zorg’ uitgebracht waarin zij de wijze beschrijft waarop de NZa voornemens is het amm-instrument toe te passen.
2 Dit artikel geeft de visie van de NZa weer zoals die in dit consultatiedocument is beschreven. Tot 17 februari 2007 is het voor eenieder mogelijk op dit consultatiedocument te reageren.- Published
- 2007
- Full Text
- View/download PDF
45. Decomplexation of Phosphirane and Phosphirene Complexes
- Author
-
G. A. van Assema, Sander, J. J. de Kanter, Frans, Schakel, Marius, and Lammertsma, Koop
- Abstract
Novel transient phosphinidene complex Ph−PMo(CO)4PMe3, generated from a 7-phosphanorbornadiene precursor, adds to CC and CC bonds to give Mo(CO)4PMe3-complexed phosphiranes and phosphirenes. The cis-PMe3ligand weakens the interaction between the molybdenum complex and the three-membered ring. Under mild CO pressure the Mo(CO)4PMe3transition metal group detaches from the phosphorus center of the ring structure by selective CO substitution. The resulting byproduct Mo(CO)5PMe3can be reused in the synthesis of the phosphinidene precursor.
- Published
- 2006
- Full Text
- View/download PDF
46. Bidentate Phosphorus Baskets by Intramolecular Phosphinidene Addition
- Author
-
van Assema, Sander G. A., Ehlers, Andreas W., de Kanter, Frans J. J., Schakel, Marius, Spek, Anthony L., Lutz, Martin, and Lammertsma, Koop
- Abstract
Intramolecular phosphinidene addition to the CC bond of Mo‐complexed, seven‐membered phosphorus heterocycles affords three novel [(diphos)Mo(CO)4] complexes (18–20). The three bidentate phosphorus baskets differ in the composition of the seven‐membered ring: one of the phosphorus atoms is flanked by CH2, NCH3, or O. The unsaturated tetrahydrophosphepine precursors are synthesized by either ring‐closing metathesis (C and N derivatives) or by a cyclization sequence (O derivative). The crystal structures of the nitrogen‐ (19) and oxygen‐containing (20) baskets have relatively small P‐Mo‐P angles of 76.240(13)° and 77.626(12)°, respectively, and complex 20has slightly shortened MoP bond lengths.
- Published
- 2006
- Full Text
- View/download PDF
47. Linear and Branched Phospha[n]triangulanes
- Author
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Slootweg, J. Chris, de Kanter, Frans J. J., Schakel, Marius, Lutz, Martin, Spek, Anthony L., Kozhushkov, Sergei I., de Meijere, Armin, and Lammertsma, Koop
- Abstract
Novel, highly stable, linear and branched mono‐ and diphospha[n]triangulanes were synthesized in high yields by the CuCl‐catalyzed phosphinidene addition to spirocyclopropanated methylenecyclopropanes and bicyclopropylidenes. The effect of spirofusion on the electronic properties of these esthetically attractive phosphacycles is apparent from X‐ray single crystal structure analyses, which reveals a tightening of the phosphirane ring on additional spirocyclopropanation, and from the NMR features that show deshielded chemical shifts for the ring‐phosphorus and ‐carbon atoms. Steric factors play a role in the addition reaction when the substrate alkene carries a second sphere of spirocyclopropane rings and causes the formation of 2‐phosphabicyclo[3.2.0]heptenes in small amounts. These by‐products most probably result from addition of the [PhP(Cl)W(CO)5]‐Cu‐L (L=alkene or solvent) reagent to the spirocyclopropanated bicyclopropylidene to give an intermediate σ‐complex, which subsequently, facilitated by steric factors, undergoes a cyclopropylcarbinyl to cyclobutyl ring expansion followed by a [1,3]‐sigmatropic shift.
- Published
- 2005
- Full Text
- View/download PDF
48. Valence Isomerization of 2-Phosphabicyclo[1.1.0]butanes
- Author
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Slootweg, J. Chris, Krill, Steffen, de Kanter, Frans J. J., Schakel, Marius, Ehlers, Andreas W., Lutz, Martin, Spek, Anthony L., and Lammertsma, Koop
- Abstract
No Abstract
- Published
- 2005
- Full Text
- View/download PDF
49. Phosphaspiropentene as a Transient Intermediate
- Author
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Slootweg, J. C., Zeist, W.-J. van, Kanter, F. J. J. de, Schakel, M., Ehlers, A. W., Lutz, M., Spek, A. L., and Lammertsma, K.
- Abstract
A phosphaspiropentene is the plausible kinetic product from the addition of dichlorocarbene to a phosphatriafulvene, which rearranges to a novel P-substituted triafulvene. The calculated barrier of 18.6 kcal mol-1 for this process is consistent with the temperature of −40 °C at which this reaction proceeds.
- Published
- 2005
50. Valence Isomerization of 2-Phosphabicyclo[1.1.0]butanesThis work was supported by the Council for Chemical Sciences of the Netherlands Organization for Scientific Research (NWO/CW).
- Author
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Slootweg, J. Chris, Krill, Steffen, de Kanter, Frans J. J., Schakel, Marius, Ehlers, Andreas W., Lutz, Martin, Spek, Anthony L., and Lammertsma, Koop
- Abstract
No Abstract
- Published
- 2005
- Full Text
- View/download PDF
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