365 research outputs found

    Causes of cerebral small vessel disease : a prospective population-based MRI study

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    __Abstract__ In the 1970s, the introduction of computed tomography (CT) and magnetic resonance imaging (MRI) in medicine, made it possible to image the living brain. These images showed that cerebral white matter lesions and asymptomatic lacunar brain infarcts are extremely common in elderly people. Evidence is accumulating that these lesions are associated with an increased risk of late-life depression, gait disturbances, and cognitive decline. Eventually, they may either by themselves or in combination with Alzheimer’s pathology and other late life degenerative changes, lead to dementia. In addition to clinically manifest infarcts and hemorrhages, white matter lesions and lacunar infarcts are frequently observed on brain images, suggesting a common etiology. Atherosclerosis-like changes and wall thickening of deep cerebral arterioles are observed on autopsy of elderly people in areas with white matter lesions and lacunar infarcts. Hence, these lesions are referred to as cerebral small vessel disease. The exact etiology of white matter lesions in elderly people is unknown and a wide variety of rare causes have been described. Nevertheless, almost all studies point to increasing age, arterial hypertension, and indicators of systemic atherosclerosis as the main risk factors. Post-mortem and blood-fl ow studies show ischemia and hypoperfusion in brain areas with large white matter lesions. Reports on the evaluation of these brain lesions over time are scarce. A better understanding of the etiology of cerebral small vessel disease could contribute to the prevention of stroke, dementia and depression, as well as more subtle cognitive decline, depressive symptoms and gait disturbances in a rapidly increasing elderly population. The objective of this thesis was to gain more insight into the etiology of cerebral small vessel disease

    The polarization losses of offset antennes

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    Method of controlling an apparatus

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    The invention relates to an apparatus comprising user operable control means for controlling the apparatus, detection means for detecting an object and determining an identity of said object, and associating means for associating control options with said identity, the control means being operable to apply said control options in response to the detection means detecting and identifying said object

    Densely integrated microring resonator based photonic devices for use in access networks

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    Two reconfigurable optical add-drop multiplexers, operating in the second or third telecom window, as well as a 1x4x4 reconfigurable λ-router operating in the second telecom window, are demonstrated. The devices have a footprint less than 2 mm2 and are based on thermally tunable vertically coupled microring resonators fabricated in Si3N4/SiO2

    Toekomstbeeld broeikasgasbalans van het Nederlandse landschap

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    De mondiale emissies van CO2 zijn de afgelopen jaren substantieel gestegen. Een afbuiging van deze trend lijkt noodzakelijk, wil de concentratie in de atmosfeer niet te hoog oplopen. De internationale gemeenschap probeert die te realiseren door stevige reductiedoelstellingen vast te stellen voor de komende tien tot dertig jaar. De inspanningen zijn gericht op terugdringen van emissies, compensatie van de uitstoot door afvang en opslag van CO2 en de omschakeling naar een duurzame energievoorziening

    Validation of the performance of a GMO multiplex screening assay based on microarray detection

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    A new screening method for the detection and identification of GMO, based on the use of multiplex PCR followed by microarray, has been developed and is presented. The technology is based on the identification of quite ubiquitous GMO genetic target elements first amplified by PCR, followed by direct hybridisation of the amplicons on a predefined microarray (DualChip® GMO, Eppendorf, Germany). The validation was performed within the framework of a European project (Co-Extra, contract no 007158) and in collaboration with 12 laboratories specialised in GMO detection. The present study reports the strategy and the results of an ISO complying validation of the method carried out through an inter-laboratory study. Sets of blind samples were provided consisting of DNA reference materials covering all the elements detectable by specific probes present on the array. The GMO concentrations varied from 1% down to 0.045%. In addition, a mixture of two GMO events (0.1% RRS diluted in 100% TOPAS19/2) was incorporated in the study to test the robustness of the assay in extreme conditions. Data were processed according to ISO 5725 standard. The method was evaluated with predefined performance criteria with respect to the EC CRL method acceptance criteria. The overall method performance met the acceptance criteria; in particular, the results showed that the method is suitable for the detection of the different target elements at 0.1% concentration of GMO with a 95% accuracy rate. This collaborative trial showed that the method can be considered as fit for the purpose of screening with respect to its intra- and inter-laboratory accuracy. The results demonstrated the validity of combining multiplex PCR with array detection as provided by the DualChip® GMO (Eppendorf, Germany) for the screening of GMO. The results showed that the technology is robust, practical and suitable as a screening too
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