100 research outputs found

    Climatology of Ultraviolet Budgets using Earth Observation (CUBEO): mapping UV from the perspective of risk assessments : final report

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    No RIVM report number in publicationThe use of satellite data to construct ground level UV-radiation maps offers a unique opportunity to investigate geographical and temporal variability of ground level UV-radiation levels related to atmospheric changes, like ozone depletion or cloud changes. The calculation of long term yearly UV-doses in combination with dose-effect models for UV-related effects, like skin cancer, further enhances the application of UV-maps as a powerful tool to support environmental assessments. This report describes the results obtained in the CUBEO-project: a Climatology of Ultraviolet Budgets using Earth Observation. The project aimed at the development and validation of UV-mapping methods that can be applied in environmental assessments. The results indicated that the satellite derived cloud correction provides accurate and representative results if the ground albedo is low. The comparison with ground based UV-measurements at different sites in Europe shows an agreement for the yearly UV-dose within 10%. An indication of the long term stability of the UV-mapping methods is obtained by means of a systematic comparison of UV-doses derived from ground based ozone and cloud data and doses derived from satellite observations over a period of nearly 20 years. The European maps of changes in UV-budgets at the ground and associated excess skin cancer risks have been reported in national and international state of the environment reports published by the National Institute of Public Health and the Environment (RIVM) and/or the European Environmental Agency (EEA). These state of the environment reports contribute to the provision of information necessary for framing and implementing sound and effective environmental policies. This investigation has been performed by order and for the account of BCRS, EU and RIVM, within the framework of the projects CUBEO and MAUVE.Beleidscommissie Remote Sensing (BCRS

    Enterocyte Shedding and Epithelial Lining Repair Following Ischemia of the Human Small Intestine Attenuate Inflammation

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    BACKGROUND: Recently, we observed that small-intestinal ischemia and reperfusion was found to entail a rapid loss of apoptotic and necrotic cells. This study was conducted to investigate whether the observed shedding of ischemically damaged epithelial cells affects IR induced inflammation in the human small gut. METHODS AND FINDINGS: Using a newly developed IR model of the human small intestine, the inflammatory response was studied on cellular, protein and mRNA level. Thirty patients were consecutively included. Part of the jejunum was subjected to 30 minutes of ischemia and variable reperfusion periods (mean reperfusion time 120 (+/-11) minutes). Ethical approval and informed consent were obtained. Increased plasma intestinal fatty acid binding protein (I-FABP) levels indicated loss in epithelial cell integrity in response to ischemia and reperfusion (p<0.001 vs healthy). HIF-1alpha gene expression doubled (p = 0.02) and C3 gene expression increased 4-fold (p = 0.01) over the course of IR. Gut barrier failure, assessed as LPS concentration in small bowel venous effluent blood, was not observed (p = 0.18). Additionally, mRNA expression of HO-1, IL-6, IL-8 did not alter. No increased expression of endothelial adhesion molecules, TNFalpha release, increased numbers of inflammatory cells (p = 0.71) or complement activation, assessed as activated C3 (p = 0.14), were detected in the reperfused tissue. CONCLUSIONS: In the human small intestine, thirty minutes of ischemia followed by up to 4 hours of reperfusion, does not seem to lead to an explicit inflammatory response. This may be explained by a unique mechanism of shedding of damaged enterocytes, reported for the first time by our group

    CD55 Deficiency Protects against Atherosclerosis in ApoE-Deficient Mice via C3a Modulation of Lipid Metabolism

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    Atherosclerosis, the leading cause of death in the Western world, is driven by chronic inflammation within the artery wall. Elements of the complement cascade are implicated in the pathogenesis, because complement proteins and their activation products are found in the atherosclerotic plaque. We examined the role of CD55, a membrane inhibitor of the complement component 3 (C3) convertase, which converts C3 into C3a and C3b, in atherosclerosis. CD55-deficient (CD55−/−) mice were crossed onto the atherosclerosis-prone apolipoprotein E (apoE)-deficient (apoE−/−) background. High fat–fed male apoE−/−/CD55−/− mice were strongly protected from developing atherosclerosis compared with apoE−/− controls. Lipid profiling showed significantly lower levels of triglycerides, nonesterified fatty acids, and cholesterol in apoE−/−/CD55−/− mice than that in controls after high-fat feeding, whereas body fat in apoE−/−/CD55−/− mice content was increased. Plasma levels of C3 fell, whereas concentrations of C3adesArg (alias acylation stimulating protein; ASP), produced by serum carboxypeptidase N–mediated desargination of C3a, increased in nonfasted high fat–fed apoE−/−/CD55−/− mice, indicating complement activation. Thus, complement dysregulation in the absence of CD55 provoked increased C3adesArg production that, in turn, caused altered lipid handling, resulting in atheroprotection and increased adiposity. Interventions that target complement activation in adipose tissue should be explored as lipid-decreasing strategies

    Platelet-Associated CD40/CD154 Mediates Remote Tissue Damage after Mesenteric Ischemia/Reperfusion Injury

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    Several innate and adaptive immune cell types participate in ischemia/reperfusion induced tissue injury. Amongst them, platelets have received little attention as contributors in the process of tissue damage after ischemia reperfusion (I/R) injury. It is currently unknown whether platelets participate through the immunologically important molecules including, CD40 and when activated, CD154 (CD40L), in the pathogenesis of I/R injury. We hypothesized that constitutive expression of CD40 and activation-induced expression of CD154 on platelets mediate local mesenteric and remote lung tissue damage after I/R injury. Wild type (WT; C57BL/6J), CD40 and CD154 deficient mice underwent mesenteric ischemia for 30 minutes followed by reperfusion for 3 hours. WT mice subjected to mesenteric I/R injury displayed both local intestinal and remote lung damage. In contrast, there was significantly less intestinal damage and no remote lung injury in CD40 and CD154 deficient mice when compared to WT mice. Platelet-depleted WT mice transfused with platelets from CD40 or CD154 deficient mice failed to reconstitute remote lung damage. In contrast, when CD40 or CD154 deficient mice were transfused with WT platelets lung tissue damage was re-established. Together, these findings suggest that multiple mechanisms are involved in local and remote tissue injury and also identify platelet-expressed CD40 and/or CD154 as mediators of remote tissue damage

    Bone marrow stromal cells attenuate sepsis via prostaglandin E2— dependent reprogramming of host macrophages to increase their interleukin-10 production

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    Sepsis causes over 200,000 deaths yearly in the US; better treatments are urgently needed. Administering bone marrow stromal cells (BMSCs—also known as mesenchymal stem cells) to mice before or shortly after inducing sepsis by cecal ligation and puncture reduced mortality and improved organ function. The beneficial effect of BMSCs was eliminated by macrophage depletion or pretreatment with antibodies specific for interleukin-10 (IL-10) or IL-10 receptor. Monocytes and/ or macrophages from septic lungs made more IL-10 when prepared from mice treated with BMSCs versus untreated mice. Lipopolysaccharide (LPS)-stimulated macrophages produced more IL-10 when cultured with BMSCs, but this effect was eliminated if the BMSCs lacked the genes encoding Toll-like receptor 4, myeloid differentiation primary response gene-88, tumor necrosis factor (TNF) receptor-1a or cyclooxygenase-2. Our results suggest that BMSCs (activated by LPS or TNF-α) reprogram macrophages by releasing prostaglandin E2 that acts on the macrophages through the prostaglandin EP2 and EP4 receptors. Because BMSCs have been successfully given to humans and can easily be cultured and might be used without human leukocyte antigen matching, we suggest that cultured, banked human BMSCs may be effective in treating sepsis in high-risk patient groups.Sepsis, a serious medical condition that affects 18 million people per year worldwide, is characterized by a generalized inflammatory state caused by infection. Widespread activation of inflammation and coagulation pathways progresses to multiple organ dysfunction, collapse of the circulatory system (septic shock) and death. Because as many people die of sepsis annually as from acute myocardial infarction1, a new treatment regimen is desperately needed. In the last few years, it has been discovered that BMSCs are potent modulators of immune responses2-5. We wondered whether such cells could bring the immune response back into balance, thus attenuating the underlying pathophysiology that eventually leads to severe sepsis, septic shock and death6,7. As a model of sepsis, we chose cecal ligation and puncture (CLP), a procedure that has been used for more than two decades8. This mouse model closely resembles the human disease: it has a focal origin (cecum), is caused by multiple intestinal organisms, and results in septicemia with release of bacterial toxins into the circulation. With no treatment, the majority of the mice die 24-48 h postoperatively. Originally published Nature Medicine, Vol. 15, No. 1, Jan 200

    Postoperative outcomes in oesophagectomy with trainee involvement

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    BACKGROUND: The complexity of oesophageal surgery and the significant risk of morbidity necessitates that oesophagectomy is predominantly performed by a consultant surgeon, or a senior trainee under their supervision. The aim of this study was to determine the impact of trainee involvement in oesophagectomy on postoperative outcomes in an international multicentre setting. METHODS: Data from the multicentre Oesophago-Gastric Anastomosis Study Group (OGAA) cohort study were analysed, which comprised prospectively collected data from patients undergoing oesophagectomy for oesophageal cancer between April 2018 and December 2018. Procedures were grouped by the level of trainee involvement, and univariable and multivariable analyses were performed to compare patient outcomes across groups. RESULTS: Of 2232 oesophagectomies from 137 centres in 41 countries, trainees were involved in 29.1 per cent of them (n = 650), performing only the abdominal phase in 230, only the chest and/or neck phases in 130, and all phases in 315 procedures. For procedures with a chest anastomosis, those with trainee involvement had similar 90-day mortality, complication and reoperation rates to consultant-performed oesophagectomies (P = 0.451, P = 0.318, and P = 0.382, respectively), while anastomotic leak rates were significantly lower in the trainee groups (P = 0.030). Procedures with a neck anastomosis had equivalent complication, anastomotic leak, and reoperation rates (P = 0.150, P = 0.430, and P = 0.632, respectively) in trainee-involved versus consultant-performed oesophagectomies, with significantly lower 90-day mortality in the trainee groups (P = 0.005). CONCLUSION: Trainee involvement was not found to be associated with significantly inferior postoperative outcomes for selected patients undergoing oesophagectomy. The results support continued supervised trainee involvement in oesophageal cancer surgery

    Evaluatie van menglaag-beschrijvingen in het EUROS model

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    The EUROS model is an air-quality model used at the Air Research Laborotory of RIVM for short (day) to long term (year) for simulations of the (chemical) dispersion of gaseous and/or airborne particulate matter on European scale. This report describes a part of ongoing development and validation work on the model to improve the models generic applicability which is one of the objectives of the RIVM project compartimental models (now: integration of regional models S711002). It focusses on the representation of dispersion processes, with the goal to improve and evaluate these processes. As such it forms a first step in the revision towards a complete three dimensional description of the transport module in the EUROS model. The work is performed within the framework of a collaboration between the Flemish institute for technological research (VITO) and RIVM. In EUROS the representation of the mixing layer and horizontal advection is improved. The new EUROS version is extensively tested and mixing layer height values are evaluated with lidar measurements. Model results for ozone concentrations and accumulated exposure (AOT) are evaluated in terms of the different mixing layer representations. The revised calculation of the mixing layer gives a much better representation of the land-sea contrast, with lower mixing heights over sea than over land, during the daytime. An important outcome is that the mixing layer concept, used in EUROS, hinders the validation of modelled concentration levels. Because, in spite of the applied scientific model improvements, modelled AOT40 levels for ozone do not show significant improvement in respect to observations. The main concern in this context is the value of the reservoir layer height in the model, which is interlaced with the mixing layer concept. Therefore, it is anticipated that a more realistic representation of the vertical exchange processes, by describing explicitly three-dimensional advection and diffusion, will improve the EUROS model results significantly, both quantitatively and qualitatively.Het EUROS model is een model voor luchtkwaliteit dat wordt gebruikt bij het RIVM-LLO voor korte (dag) en lange termijn (jaar) simulaties van chemische verspreiding van gassen of fijnstof op Europese schaal. Dit rapport beschrijft een deel van lopend ontwikkelings- en validatiewerk aan het model om de generieke toepasbaarheid van het model te verbeteren. Dit is een van de doelen van het RIVM project 'compartimentele modellen/integratie regionale modellen. Er wordt gefocust op de beschrijving van de verspreidings processen, met als doel deze processen te evalueren en te verbeteren. Als zodanig vormt het een eerste stap in de overgang naar een complete drie-dimensionale beschrijving van de EUROS transport module. Het onderzoek is uitgevoerd in het kader van een samenwerkingsovereenkomst met de Vlaamse Instelling voor Technologische Ontwikkeling (VITO) en RIVM. De beschrijving van de menglaag en horizontale advectie in het EUROS model is verbeterd. De nieuwe EUROS versie is uitvoerig getest en de menglaaghoogtes zijn vergeleken met lidar metingen. Modelresultaten voor ozonconcentraties en geintegreerde blootstellings nivo's (AOT) zijn geevalueerd in termen van de verschillende menglaagbeschrijvingen. De herziene beschrijving van de menglaag geeft een veel betere weerspiegeling van het land-zee contrast, met lagere menglaaghoogtes boven zee dan boven land gedurende de dag. Een belangrijk resultaat is dat het menglaagconcept, dat in het EUROS model wordt gebruikt, een validatie van de gemodeleerde waarden bemoeilijkt. Dit is omdat de gemodelleerde ozon AOT40 nivo's geen significante verbetering laten zien in vergelijking met metingen, in tegenstelling tot de aangebrachtte wetenschappelijke verbeteringen. Het belangrijkste aspect in deze context is de waarde van de reservoirlaaghoogte in het model. De reservoirlaaghoogte is gelieerd aan het menglaag concept. Daarom wordt verwacht dat een realistischere beschrijving van de verticale uitwisselingsprocessen, door een explicite beschrijving van 3D advectie en diffusie, de resultaten van het EUROS significant zal verbeteren, zowel kwantitatief als kwalitatief

    Evaluatie van menglaag-beschrijvingen in het EUROS model

    No full text
    Het EUROS model is een model voor luchtkwaliteit dat wordt gebruikt bij het RIVM-LLO voor korte (dag) en lange termijn (jaar) simulaties van chemische verspreiding van gassen of fijnstof op Europese schaal. Dit rapport beschrijft een deel van lopend ontwikkelings- en validatiewerk aan het model om de generieke toepasbaarheid van het model te verbeteren. Dit is een van de doelen van het RIVM project 'compartimentele modellen/integratie regionale modellen. Er wordt gefocust op de beschrijving van de verspreidings processen, met als doel deze processen te evalueren en te verbeteren. Als zodanig vormt het een eerste stap in de overgang naar een complete drie-dimensionale beschrijving van de EUROS transport module. Het onderzoek is uitgevoerd in het kader van een samenwerkingsovereenkomst met de Vlaamse Instelling voor Technologische Ontwikkeling (VITO) en RIVM. De beschrijving van de menglaag en horizontale advectie in het EUROS model is verbeterd. De nieuwe EUROS versie is uitvoerig getest en de menglaaghoogtes zijn vergeleken met lidar metingen. Modelresultaten voor ozonconcentraties en geintegreerde blootstellings nivo's (AOT) zijn geevalueerd in termen van de verschillende menglaagbeschrijvingen. De herziene beschrijving van de menglaag geeft een veel betere weerspiegeling van het land-zee contrast, met lagere menglaaghoogtes boven zee dan boven land gedurende de dag. Een belangrijk resultaat is dat het menglaagconcept, dat in het EUROS model wordt gebruikt, een validatie van de gemodeleerde waarden bemoeilijkt. Dit is omdat de gemodelleerde ozon AOT40 nivo's geen significante verbetering laten zien in vergelijking met metingen, in tegenstelling tot de aangebrachtte wetenschappelijke verbeteringen. Het belangrijkste aspect in deze context is de waarde van de reservoirlaaghoogte in het model. De reservoirlaaghoogte is gelieerd aan het menglaag concept. Daarom wordt verwacht dat een realistischere beschrijving van de verticale uitwisselingsprocessen, door een explicite beschrijving van 3D advectie en diffusie, de resultaten van het EUROS significant zal verbeteren, zowel kwantitatief als kwalitatief.The EUROS model is an air-quality model used at the Air Research Laborotory of RIVM for short (day) to long term (year) for simulations of the (chemical) dispersion of gaseous and/or airborne particulate matter on European scale. This report describes a part of ongoing development and validation work on the model to improve the models generic applicability which is one of the objectives of the RIVM project compartimental models (now: integration of regional models S711002). It focusses on the representation of dispersion processes, with the goal to improve and evaluate these processes. As such it forms a first step in the revision towards a complete three dimensional description of the transport module in the EUROS model. The work is performed within the framework of a collaboration between the Flemish institute for technological research (VITO) and RIVM. In EUROS the representation of the mixing layer and horizontal advection is improved. The new EUROS version is extensively tested and mixing layer height values are evaluated with lidar measurements. Model results for ozone concentrations and accumulated exposure (AOT) are evaluated in terms of the different mixing layer representations. The revised calculation of the mixing layer gives a much better representation of the land-sea contrast, with lower mixing heights over sea than over land, during the daytime. An important outcome is that the mixing layer concept, used in EUROS, hinders the validation of modelled concentration levels. Because, in spite of the applied scientific model improvements, modelled AOT40 levels for ozone do not show significant improvement in respect to observations. The main concern in this context is the value of the reservoir layer height in the model, which is interlaced with the mixing layer concept. Therefore, it is anticipated that a more realistic representation of the vertical exchange processes, by describing explicitly three-dimensional advection and diffusion, will improve the EUROS model results significantly, both quantitatively and qualitatively.RIV

    Safety distances for hydrogen filling stations

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    In the context of spatial planning the Dutch Ministry of Housing, Spatial Planning and the Environment asked the Centre for External Safety of the National Institute for Public Health and the Environment (RIVM) to advice on safe distances pertaining to hydrogen filling stations. The RIVM made use of failure modeling and parameters for calculating the distance in detail. An imaginary hydrogen filling station for cars is used in the determination of ‘external safety’ or third party distances for the installations and the pipe work for three different sizes of hydrogen filling stations. For several failure scenarios ‘effect’ distances are calculated for car filling at 350 and 700 bar. Safe distances of filling stations from locations where people live and work appear to be similar for compressed hydrogen, gasoline/petrol and compressed natural gas. Safe distances for LPG are greater. A filling unit for hydrogen can be placed at gasoline/petrol-filling stations without increasing safety distance
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