1,205 research outputs found

    Endothelium—role in regulation of coagulation and inflammation

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    By its strategic position at the interface between blood and tissues, endothelial cells control blood fluidity and continued tissue perfusion while simultaneously they direct inflammatory cells to areas in need of defense or repair. The endothelial response depends on specific tissue needs and adapts to local stresses. Endothelial cells counteract coagulation by providing tissue factor and thrombin inhibitors and receptors for protein C activation. The receptor PAR-1 is differentially activated by thrombin and the activated protein C/EPCR complex, resulting in antithrombotic and anti-inflammatory effects. Thrombin and vasoactive agents release von Willebrand factor as ultra-large platelet-binding multimers, which are cleaved by ADAMTS13. Platelets can also facilitate leukocyte-endothelium interaction. Platelet activation is prevented by nitric oxide, prostacyclin, and exonucleotidases. Thrombin-cleaved ADAMTS18 induces disintegration of platelet aggregates while tissue-type plasminogen activator initiates fibrinolysis. Fibrin and products of platelets and inflammatory cells modulate the angiogenic response of endothelial cells and contribute to tissue repair

    FGFR1 and the bloodline of the vasculature

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    Myocardial ischemia after orthotopic liver transplantation

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    A hypercoagulable state exists after orthotopic liver transplantation. This hematologic abnormality may predispose patients to coronary thrombosis and unstable angina. The incidence of post-operative myocardial ischemia in such patients is unknown. Suitable electrocardiograms and clinical events of consecutive patients undergoing orthotopic liver transplantation (n = 45) and major intraabdominal surgery (n = 28) during a 3-month period at a major university teaching hospital and transplant center were examined retrospectively. Clinical myocardial ischemia or ischemic electrocardiographic changes, or both, occurred in 6 transplant patients compared with no patient in the nontransplant or comparison group. In 4 of the 6 patients with dramatic electrocardiographic changes and ischemic events, coronary arteriography failed to demonstrate significant obstructive disease. It is concluded that severe myocardial ischemia may occur in patients after orthotopic liver transplantation in the absence of significant coronary disease. A hypercoagulable state may predispose to coronary thrombosis in this setting, providing insight (and a future model for study) into the development of unstable angina. © 1994

    Enhancing vehicle destination prediction using latent trajectory information

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    Intelligent transportation systems have the potential to provide road users with a range of useful applications, including vehicle preconditioning, traffic flow management and intelligent parking recommendations. The majority of these applications can benefit from knowledge of vehicle activities (common situations that a vehicle encounters e.g. traffic), along with the upcoming destinations that a vehicle will visit. We focus on the trajectories that vehicles provide, and the data contained within them, in order to ascertain information about the patterns in individuals' mobility data. Machine learning has been used in many different vehicle applications, and we focus on using these techniques to predict the activity of a vehicle and its future destinations. Clustering methods can be applied at the level of trajectories or the individual instances within them, and we explore both of these alternatives in this thesis. Additionally, we explore several classification approaches to predict activities and destinations. In developing our methods, we make use of a combination of both geospatial and temporal data along with on-board vehicle sensor data. This thesis presents novel methods for filtering stay points to identify points of interest and applying destination prediction to vehicle trajectories. Existing methods for stay point detection are not specific to vehicles, and therefore any region of low mobility is potentially considered to be of interest. We propose a novel method for filtering the extracted stay points to identify points of interest, using vehicle data to predict vehicle activities. The predicted activities are further used to represent trajectories as sequences of annotated locations, to inform the detection of similarities between journeys. Finally, this thesis presents a novel method for using additional properties of a trajectory to cluster trajectories into groupings of similar trajectories with the aim of improving the accuracy of destination prediction. We evaluate our proposed methods on a set of vehicle datasets, varying in purpose and the data available

    Vehicle point of interest detection using in-car data

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    Intelligent transportation systems often identify and make use of locations extracted from GPS trajectories to make informed decisions. However, many of the locations identified by existing systems are false positives, such as those in heavy traffic. Signals from the vehicle, such as speed and seatbelt status, can be used to identify these false positives. In this paper, we (i) demonstrate the utility of the Gradient-based Visit Extractor (GVE) in the automotive domain, (ii) propose a classification stage for removing false positives from the location extraction process, and (iii) evaluate the effectiveness of these techniques in a high resolution vehicular dataset
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