1,783 research outputs found
Smoking during pregnancy and prenatal programming:Consequences for DNA methylation
Full text linkRoken tijdens de zwangerschap verhoogt het risico op het ontwikkelen de chronische roken gerelateerde longziekte COPD later in het leven. Dit suggereert dat het ontstaan van COPD z’n oorsprong al kan hebben tijdens de foetale ontwikkeling in de baarmoeder. Risicofactoren voor een bepaalde ziekte kunnen erfelijk zijn en liggen dan vast in ons genetisch materiaal, ons DNA. Daarnaast ontstaan ook veranderingen in het gebruik van het DNA tijdens het leven. Dit zijn zogenaamde epigenetische veranderingen. Epigenetische mechanismen zoals DNA-methylering kunnen hierbij onderliggend zijn. UMCG onderzoeker Karolin Meyer onderzocht de schadelijke effecten van roken tijdens de zwangerschap in een muismodel voor COPD. Prenataal blootgestelde foetale en neonatale hadden een lager geboortegewicht en een lagere genexpressie van Igf1 en Igf1r in de lever en longen. De IGF1-signaleringsroute is belangrijk voor foetale ontwikkeling. De expressie van Igf1 en Igf1r was omgekeerd gecorreleerd met DNA-methylering in de Igf1- en Igf1r-genen. Dit effect was orgaan, leeftijd en geslachtsafhankelijk. Bovendien veranderde de prenatale rookblootstelling DNA-methylering van het Cyp2a5-gen. Dit gen is belangrijk voor het ontgiften van nicotine. In toekomstige studies zullen de gevolgen van Cyp2a5 hypermethylatie verder onderzocht worden in relatie met het ontgiften van sigarettenrook en gevoeligheid voor nicotine verslaving. De onderzoek werd uitgevoerd bij de afdeling Pathologie en Medische Biologie van het UMCG en binnen het onderzoeksinstituut GRIAC en onderzoeksschool GUIDE. Het onderzoek werd begeleid door dr. MN Hylkema en dr. T Plosch en werd gefinancierd door het Longfonds. Het proefschrift is getiteld "Roken tijdens de zwangerschap en prenatale programmering - gevolgen voor DNA-methylering
Farming exposure and asthma phenotypes: In mice and men
Full text linkAlthough several studies have shown that farmers and people with agricultural-related occupations have a higher risk of developing lung diseases such as nonallergic asthma, chronic bronchitis and chronic obstructive pulmonary disease (COPD), it has also been shown that exposure to the farm environment is associated with a protective effect on the development of atopy and allergic asthma. In this thesis, both effects of farm exposures on the immune system were studied: the protective effect against allergic asthma and the induction of non-allergic asthma. These studies were conducted among agricultural workers, and in mouse models of allergic and nonallergic lung disease. In addition, the presence of several macrophage phenotypes in animal models of allergic and non-allergic asthma was investigated, as well as the effects of exposure to farm dust extract on a macrophage cell line. This thesis demonstrated that occupational exposure to a farm environment and exposure to farm dust extracts in mice lead to a shift in the immune system towards non-allergic inflammation. This shift offers on the one hand protection against development of allergic diseases, such as allergic asthma, but is also associated with the risk of nonallergic asthma development. In addition, this thesis shows that, within the various phenotypes asthma, various inflammatory mediators and cells are important in the development and severity of airway hyperresponsiveness
Symptomatic and asymptomatic airway hyperresponsiveness : epidemiological and pathological studies
Full text linkIn this thesis, we described the relationship of various allergy markers and the development of pulmonary function with the single or coinciding presence of respiratory syptoms and airway hyperresponsiveness (AHR) in a general adult population. Further, we investigated whether differences in inflammatory cells exist in the airways of subjects with and without respiratory symptoms and AHR. Further, factors associated with airway hyperresponsiveness (AHR) and possible mechanisms of AHR are discussed. ...
Zie: Summary.
Floating WIM Threshold Concept for Truck Weight Enforcement
Full text linkWeigh stations are the primary weight compliance checkpoints for commercial trucks. In the past several decades, states have used weigh-in-motion (WIM) technology to reduce delay and increase enforcement on overweight vehicles. This study offers a detailed analysis of weigh station systems and presents floating-threshold algorithms to improve the efficiency of WIM equipped weigh stations.
This research evaluates weigh station design and operational parameters using queueing theory and found that WIM technology not only enhances the effectiveness and efficiency of weigh station operations but also largely reduces travel delay for trucking companies. The effects of truck demand, truck weight distribution, static scale service time, WIM accuracy, and sorting threshold on weigh station operations have been analyzed. The author shows the importance of transponders in a WIM mainline weigh station operation. The author also proves that the increase of storage spaces within a weigh station may largely increase truck travel delay and does not significantly improve weigh station operations.
This research focuses on the development of floating-threshold algorithms. Since the number of trucks, particularly heavy trucks, has increased rapidly in recent decades, many weigh stations cannot meet the demand even when equipped with WIM systems. This problem is complicated by the fact that truck demands, truck weight distribution, and static scale service time vary by time of day and day of week. The author designed floating-threshold algorithms to automatically adapt to high truck demand and the varying of truck demand, truck weight distribution, and static scale service time, over time. When the queue at the weigh station is long, the threshold value is increased so as to avoid the closure of the weigh station while still catching the worst weight limit offenders. When the queue is short, the threshold value is lowered to increase the number of trucks inspected. Both the traditional fixed-threshold strategy and two floating-threshold strategies were modeled and tested using a microscopic simulation model. The results show that floating-threshold strategies are both more effective in weight enforcement and more efficient for heavy traffic flow and high-variance environments. The finding that different floating-threshold strategies have different effects indicates that it is necessary to make a further study on floating-threshold algorithms
Early life exposure to toxic environments: effects on lung and immune cell development in mice and men
Full text linkBevolkingsonderzoek laat zien dat kinderen van moeders die rookten tijdens de zwangerschap een grotere kans hebben op het krijgen van longinfecties en astma. Daarnaast lijkt het erop dat nakomelingen van een rokende moeder een groter risico hebben op het krijgen van de rookgerelateerde ziekte COPD (chronisch obstructieve longziekte), later in het leven. In China is het aantal vrouwen dat zelf rookt erg laag maar daar wordt de bevolking met name blootgesteld aan schadelijke stoffen die vrijkomen door het steeds groeiende aantal ouderwetse auto’s en de vervuilende industrie. Een voorbeeld hiervan is de recycling industrie, waarbij vaak op primitieve en onveilige wijze, zoals verbranding, elektronica wordt gerecycled. Daarbij komt een mengsel van chemicaliën vrij die bekend staan om hun schadelijke effecten op de gezondheid zoals lood, kwik, cadmium en het kankerverwekkende polychloorbifenyl (pcb). Daarmee lopen zwangere vrouwen en jonge kinderen in gebieden waar elektronica recycling (e-waste) plaatsvindt een groot risico op het krijgen van gezondheidsproblemen. UMCG-promovendus Junjun Cao onderzocht in Groningen de schadelijke effecten van roken tijdens de zwangerschap in een muizenmodel voor COPD. Nakomelingen van moeders die aan rook waren blootgesteld tijdens de zwangerschap hadden minder trilhaardragende epitheel cellen die nodig zijn voor het schoon houden van de long. Daarnaast bleek roken tijdens de zwangerschap in de nakomelingen effecten te hebben op genen die betrokken zijn bij oxidatieve stress, veroudering en longweefselherstel. In China onderzocht Cao de schadelijke effecten van blootstelling aan de elektronica recycling industrie. In jonge kinderen die opgroeien in een berucht vervuild gebied in China vond hij een verstoring van het immuun systeem in het bloed. Langdurige blootstelling kan hiermee grote gevolgen hebben voor de gezondheid van deze kinderen
The Impact of Tourism on Curacao's Economy: A Scenario Approach
No full textCuraçao is an autonomous countrywithin the Kingdom of the Netherlands. The governmentwants to support tourism development. However,various development strategies are possible. This articlepresents four scenarios of marketing and investmentstrategies that will affect the number of tourists fromThe Netherlands and North America (USA and Canada)in different ways. A multiplier model was used to calculatethe economic impacts of the four scenarios. Bydoing so, this article shows how the government’s decisionto support particular marketing and investmentstrategies may have certain outcomes for the number ofjobs in Curaçao’s tourism industry
Model Validation and New Water Control Strategies in Drinking Water Treatment Plant Wim Mensink
No full textStimela is an environment for standardized mathematical models of drinking water treatment processes. It can be used to predict the future water treatment situation which may happen or change. In water treatment plant Wim Mensink, the Stimela model train was set up to compare with other alternative water control strategies. Before starting the work of developing new water control strategies with Stimela model, Stimela model for Wim Mensink must be validated so that the model can be seen as a reliable and stable tool for the next work. Before the validation work, the current water control strategy for the treatment process needs to be investigated clearly to fulfil all the input control information is correct. Besides this, an experiment for obtaining the measured results of pellet diameters over different layers was performed in Wim Mensink. The validation work starts with single pellet softening process for three different reactors over first month from January 20th to February 20th. The fluidized bed height, pressure drop over total height of reactor, pellet diameters and porosities are validated. After that, the validation work is integrated with whole water treatment system to prove the function of pellet softening reactor and the four important water quality parameters over two important locations (after weir aerator location and final RO mixing location). The validated results of softening process are analysed by the relative error way to prove the reliability of the model results compared with measured results. The final step of the thesis work is developing the new water control strategies to optimize the current control plans of Wim Mensink. Five different water control strategies are put forward. They can be either reached separately according to their own advantages and limitations or fulfil with a step by step order as a whole optimization process. Moreover, the other water control strategies developed by engineering consultancy company DHV are evaluated here with Stimela model so that they can be proved reliable and achievable. In the future, the application of Stimela model will be spread over all the drinking water treatment plants in the Netherlands and contributes to the central automated control as a drinking water treatment operator training simulator.Sanitary EngineeringWatermanagementCivil Engineering and Geoscience
Use of Axle Load Spectra (ALS) for Estimating Calibration Drift in Weigh-In-Motion (WIM) Systems
Full text linkThis analysis's main objective is to determine WIM system errors based on axle loading without physically performing WIM equipment performance validation using test trucks. The presented methodology can be used to estimate systematic errors (calibration drift) in the WIM system at any point in time after the equipment calibration. This approach can help highway agencies select optimum timings for routine maintenance and calibration of WIM equipment without compromising its accuracy. The results show that the WIM accuracy for the single axle (SA) and tandem axle (TA) can be estimated with SA and TA NALS shape factors with an acceptable degree of error for bending plate (BP) and quartz piezo QP) sensors. The application and significance of the developed models were explained with the help of an example. The use of NALS to estimate the WIM system accuracy can save a significant amount of time and resources required for field validation of WIM performance every year.The presentation of the authors' names and (or) special characters in the title of the pdf file of the accepted manuscript may differ slightly from what is displayed on the item page. The information in the pdf file of the accepted manuscript reflects the original submission by the author
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