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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
111

Alteration of endothelium-derived hyperpolarizing factor due to hypoxia-reoxygenation: implications in cardiac surgery.

January 2005 (has links)
Dong Yingying. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2005. / Includes bibliographical references (leaves 99-125). / Abstracts in English and Chinese. / Declaration --- p.i / Acknowledgement --- p.ii / Publication list --- p.iii / Abstract (English) --- p.ix / Abstract (Chinese) --- p.xii / Abbreviations --- p.xiv / List of figures / tables --- p.xvi / Chapter Chapter 1. --- General Introduction / Chapter 1.1 --- The role of endothelium in regulating vascular tone --- p.1 / Chapter 1.1.1 --- Nitric oxide (NO) --- p.2 / Chapter 1.1.2 --- Endothelium-derived hyperpolarizing factor (EDHF) --- p.7 / Chapter 1.1.3 --- Prostacyclin (PGI2) --- p.20 / Chapter 1.2 --- EDHF-mediated endothelial function in coronary circulation --- p.22 / Chapter 1.2.1 --- Role of EDHF in coronary microarteries --- p.23 / Chapter 1.2.2 --- Role of EDHF in cardiac veins --- p.24 / Chapter 1.3 --- Effect of ischemia-reperfusion on endothelial function in coronary circulation --- p.25 / Chapter 1.3.1 --- Ischemia-reperfusion injury --- p.26 / Chapter 1.3.2 --- Effect of ischemia-reperfusion on endothelial function in coronary microarteries --- p.28 / Chapter 1.3.3 --- Effect of ischemia-reperfusion on endothelial function in cardiac veins --- p.29 / Chapter 1.4 --- Alteration of endothelial function during cardiac surgery / Chapter 1.4.1 --- Cardioplegia and organ preservation solutions --- p.31 / Chapter 1.4.2 --- Combined effects of hypoxia-reoxygenation and ST solution on endothelial function in coronary microarteries/cardiac veins --- p.34 / Chapter 1.4.3 --- Effect of nicorandil on endothelial function --- p.34 / Chapter Chapter 2. --- Materials and Methods --- p.37 / Chapter 2.1 --- Isometric force study in micro arteries/veins --- p.37 / Chapter 2.1.1 --- Preparation of vessels --- p.37 / Chapter 2.1.1.1 --- Preparation of porcine coronary microarteries --- p.37 / Chapter 2.1.1.2 --- Preparation of porcine cardiac veins --- p.37 / Chapter 2.1.2 --- Technique of setting up --- p.39 / Chapter 2.1.2.1 --- Mounting of microvessels --- p.39 / Chapter 2.1.2.2 --- Normalization procedure for microvessels --- p.39 / Chapter 2.1.3 --- EDHF-mediated vasorelaxation --- p.40 / Chapter 2.1.3.1 --- Precontraction and stimuli of EDHF --- p.40 / Chapter 2.1.3.2. --- “Truéحresponse of EDHF --- p.40 / Chapter 2.1.4 --- Data acquisition and analysis --- p.41 / Chapter 2.2 --- Hypoxia and reoxygenation --- p.41 / Chapter 2.2.1 --- Calibration of 02-special electrode --- p.41 / Chapter 2.2.2 --- Measurement of --- p.02 / Chapter 2.3 --- Statistical analysis --- p.42 / Chapter 2.4 --- Chemicals --- p.43 / Chapter Chapter 3. --- Hypoxia-Reoxygenation in Coronary Microarteries: Combined Effect with St Thomas Cardioplegia and Temperature on the Endothelium- derived Hyperpolarizing Factor and Protective Effect of Nicorandil --- p.44 / Chapter 3.1 --- Abstract --- p.44 / Chapter 3.2 --- Introduction --- p.45 / Chapter 3.3 --- Experimental design and analysis --- p.47 / Chapter 3.3.1 --- Vessel Preparation --- p.47 / Chapter 3.3.2 --- Normalization --- p.48 / Chapter 3.3.3 --- Hypoxia --- p.48 / Chapter 3.3.4 --- Effect of H-R on EDHF-mediated relaxation in coronary microarteries --- p.49 / Chapter 3.3.5 --- Combined effects ofH-R and ST solution on EDHF-mediated relaxation in coronary microarteries --- p.49 / Chapter 3.3.6 --- Effect of addition of nicorandil Krebs or ST solution under H-R on EDHF-mediated relaxation in coronary microarteries --- p.49 / Chapter 3.3.7 --- Data analysis --- p.50 / Chapter 3.4 --- Results --- p.51 / Chapter 3.4.1 --- Resting force --- p.51 / Chapter 3.4.2 --- U46619-induced contraction force --- p.51 / Chapter 3.4.3 --- Partial pressure of oxygen in hypoxia --- p.51 / Chapter 3.4.4 --- EDHF-mediated relaxation in coronary microarteries --- p.51 / Chapter 3.4.4.1 --- Effect of H-R --- p.51 / Chapter 3.4.4.2 --- Combined effects ofH-R and ST solution on EDHF-mediated relaxation --- p.52 / Chapter 3.4.4.3 --- Effects of addition of nicorandil to Krebs or ST solution under H-R on EDHF-mediated relaxation --- p.52 / Chapter 3.5 --- Discussion --- p.53 / Chapter 3.5.1 --- EDHF-mediated relaxation after exposure to H-R --- p.53 / Chapter 3.5.2 --- EDHF-mediated relaxation after H-R in ST solution at different temperature --- p.54 / Chapter 3.5.3 --- Effect of addition of nicorandil to Krebs or ST solution during H-R on EDHF-mediated relaxation --- p.55 / Chapter 3.5.4 --- Clinical implications --- p.56 / Chapter Chapter 4. --- Hypoxia-Reoxygenation in Cardiac Microveins: Combined Effect with Cardioplegia and Temperature on the Endothelial Function --- p.68 / Chapter 4.1 --- Abstract --- p.68 / Chapter 4.2 --- Introduction --- p.69 / Chapter 4.3 --- Experimental design and analysis --- p.73 / Chapter 4.3.1 --- Vessel Preparation --- p.73 / Chapter 4.3.2 --- Normalization --- p.73 / Chapter 4.3.3 --- Hypoxia --- p.73 / Chapter 4.3.4 --- Effect of H-R on EDHF-mediated relaxation in cardiac micro veins --- p.74 / Chapter 4.3.5 --- Combined effects of H-R and ST solution on EDHF-mediated relaxation in cardiac microveins --- p.74 / Chapter 4.3.6 --- Data analysis --- p.75 / Chapter 4.4 --- Results --- p.75 / Chapter 4.4.1 --- Resting force --- p.75 / Chapter 4.4.2 --- U46619-induced contraction force --- p.76 / Chapter 4.4.3 --- Partial pressure of oxygen in hypoxia --- p.76 / Chapter 4.4.4 --- EDHF-mediated relaxation after H-R in Krebs solution at 37°C --- p.76 / Chapter 4.4.5 --- EDHF-mediated relaxation after exposure to H-R in ST solution at different temperatures --- p.77 / Chapter 4.5 --- Discussion --- p.78 / Chapter 4.5.1 --- Effect of H-R on EDHF-mediated relaxation --- p.78 / Chapter 4.5.2 --- Combined effects of H-R with ST solution on EDHF-mediated relaxation --- p.80 / Chapter 4.5.3 --- Clinical implications / Chapter Chapter 5. --- General Discussion --- p.89 / Chapter 5.1 --- EDHF-mediated endothelial function in porcine coronary circulation --- p.89 / Chapter 5.1.1 --- EDHF in porcine coronary microarteries --- p.92 / Chapter 5.1.2 --- EDHF in porcine cardiac veins --- p.90 / Chapter 5.2 --- Alteration of EDHF-mediated function after exposure to H-R --- p.91 / Chapter 5.2.1 --- In coronary microarteries --- p.91 / Chapter 5.2.2 --- In cardiac veins --- p.92 / Chapter 5.3 --- Alteration of EDHF-mediated function after exposure to ST solution under H-R --- p.92 / Chapter 5.3.1 --- In coronary microarteries --- p.93 / Chapter 5.3.2 --- In cardiac veins --- p.93 / Chapter 5.4 --- EDHF-mediated function in nicorandil-supplemented ST solution under H-R in coronary microarteries --- p.93 / Chapter 5.5 --- Clinical implications / Chapter 5.5.1 --- H-R injury --- p.94 / Chapter 5.5.2 --- H-R injury and cardioplegic solution --- p.95 / Chapter 5.5.2 --- Nicorandil-supplementation in cardioplegic solution --- p.95 / Chapter 5.6 --- Limitation of the study --- p.96 / Chapter 5.7 --- Future investigations --- p.96 / Chapter 5.8 --- Conclusions --- p.97 / References --- p.99
112

Studies of danshen and its constituents on rat vascular preparations. / Studies of danshen & its constituents on rat vascular preparations

January 2005 (has links)
Cheung Ho Yan. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2005. / Includes bibliographical references (leaves 164-175). / Abstracts in English and Chinese. / Abstract --- p.i / Acknowledgements --- p.vi / Publications based on the work in this thesis --- p.vii / Table of content --- p.viii / Abbreviations --- p.xii / Chapter CHAPTER 1 --- INTRODUCTION --- p.1 / Chapter 1.1 --- Traditional Chinese Medicine --- p.1 / Chapter 1.1.1 --- Danshen --- p.2 / Chapter 1.1.2 --- Chemical constituents --- p.5 / Chapter 1.1.3 --- Pharmacological effects --- p.7 / Chapter 1.1.3.1 --- On blood vessels --- p.7 / Chapter 1.1.3.2 --- On blood pressure --- p.8 / Chapter 1.1.3.3 --- On heart --- p.8 / Chapter 1.1.3.4 --- On myocardial ischaemia and reperfusion --- p.9 / Chapter 1.1.3.5 --- On platelet activity --- p.10 / Chapter 1.1.3.6 --- Other actions --- p.11 / Chapter 1.1.4 --- Clinical studies --- p.12 / Chapter 1.2 --- The Vascular System --- p.13 / Chapter 1.2.1 --- The circulation network --- p.13 / Chapter 1.2.2 --- Physiology of blood vessels --- p.13 / Chapter 1.2.3 --- Control of vascular lone --- p.14 / Chapter 1.3 --- Mechanisms of Vasodilatation --- p.16 / Chapter 1.3.1 --- Endothelium derived relaxant factors (EDRFs) --- p.16 / Chapter 1.3.1.1 --- Nitric oxide (NO) --- p.16 / Chapter 1.3.1.2 --- Prostacyclin (PGI:) --- p.17 / Chapter 1.3.1.3 --- Endotheliun-derived hyperpolarization factors (EDHFs) --- p.18 / Chapter 1.3.1.3.1 --- Epoxyeicosatrienoic acids (EETs) --- p.19 / Chapter 1.3.1.3.2 --- Potassium ion (IC) --- p.20 / Chapter 1.3.1.3.3 --- Gap junction --- p.20 / Chapter 1.3.2 --- Signal transduction pathways --- p.21 / Chapter 1.3.2.1 --- Guanylyl cyclase-cGMP pathway --- p.21 / Chapter 1.3.2.2 --- Adenylyl cyclase-cAMP pathway --- p.22 / Chapter 1.3.3 --- Ion channels in vascular smooth muscle cell --- p.24 / Chapter 1.3.3.1 --- Potassium channels (K+ channels) --- p.24 / Chapter 1.3.3.2 --- Calcium channels (Ca2+ channels) --- p.24 / Chapter 1.3.3.3 --- Chloride channel (Cl channel) --- p.25 / Chapter 1.3.4 --- Receptor-operated mechanisms --- p.27 / Chapter 1.3.4.1 --- Muscarinic receptors --- p.27 / Chapter 1.3.4.2 --- Adrenoceptors --- p.27 / Chapter 1.3.4.3 --- Histamine receptors --- p.28 / Chapter 1.3.4.4 --- CGRP receptors --- p.29 / Chapter 1.3.4.5 --- Tachykinin receptors --- p.30 / Chapter 1.4 --- Aims of the studies --- p.31 / Chapter CHAPTER 2 --- MATERIALS AND METHODS --- p.32 / Chapter 2.1 --- Extraction of Water and Lipid-solubie Fractions from Danshen --- p.32 / Chapter 2.1.1 --- Preparation of water-soluble and lipid-soluble fractions --- p.33 / Chapter 2.2 --- Experiments on Rat Knee Joint --- p.35 / Chapter 2.2.1 --- Animals --- p.35 / Chapter 2.2.2 --- Materials --- p.35 / Chapter 2.2.3 --- Preparatory protocols --- p.37 / Chapter 2.2.3.1 --- Anaesthesia of animals --- p.37 / Chapter 2.2.3.2 --- Cannulation of trachea --- p.37 / Chapter 2.2.3.3 --- Cannulation of carotid artery --- p.38 / Chapter 2.2.3.4 --- Blood pressure measurement --- p.38 / Chapter 2.2.4 --- Measurement of knee joint blood flow --- p.39 / Chapter 2.2.4.1 --- Preparation for measurement of knee joint blood flow --- p.41 / Chapter 2.2.5 --- Experimental protocols --- p.41 / Chapter 2.2.5.1 --- Danshen on knee joint blood flow --- p.41 / Chapter 2.2.5.2 --- Antagonists on Danshen --- p.41 / Chapter 2.2.5.3 --- Positive controls --- p.43 / Chapter 2.2.6 --- Image analysis --- p.44 / Chapter 2.2.7 --- Data analysis --- p.44 / Chapter 2.3 --- Experiments on Rat Femoral Artery --- p.45 / Chapter 2.3.1 --- Animals --- p.45 / Chapter 2.3.2 --- Materials --- p.45 / Chapter 2.3.2.1 --- Chemicals --- p.45 / Chapter 2.3.2.2 --- Physiological salt solution --- p.48 / Chapter 2.3.3 --- Preparatory protocols --- p.48 / Chapter 2.3.3.1 --- Small vessel myograph --- p.48 / Chapter 2.3.3.2 --- Isolation and mounting of tissue --- p.49 / Chapter 2.3.4 --- Experimental protocols --- p.50 / Chapter 2.3.4.1 --- Studies on the vasodilator response to Danshen --- p.50 / Chapter 2.3.4.2 --- Studies of antagonists on Danshen --- p.50 / Chapter 2.3.4.2.1 --- Endothelium-dependent mechanisms --- p.51 / Chapter 2.3.4.2.2 --- Endothelium-independent mechanisms --- p.54 / Chapter 2.3.4.2.3 --- K+ channel blockers --- p.54 / Chapter 2.3.4.2.4 --- Positive controls --- p.55 / Chapter 2.3.4.3 --- Danshen on Ca2+-induced contraction --- p.56 / Chapter 2.3.5 --- Data analysis --- p.57 / Chapter CHAPTER 3 --- RESULTS --- p.58 / Chapter 3.1 --- Danshen on Rat Knee Joint Blood Flow --- p.58 / Chapter 3.1.1 --- Topical administration of Danshen --- p.58 / Chapter 3.1.2 --- Antagonists on Danshen --- p.59 / Chapter 3.1.2.1 --- Muscarinic receptor antagonist --- p.59 / Chapter 3.1.2.2 --- β-adrenoceptor antagonist --- p.60 / Chapter 3.1.2.3 --- Histamine receptor antagonists --- p.60 / Chapter 3.1.2.4 --- Nitric oxide synthase inhibitor --- p.61 / Chapter 3.1.2.5 --- Cyclo-oxygenase inhibitors --- p.62 / Chapter 3.1.2.6 --- CGRPi receptor antagonist --- p.62 / Chapter 3.1.2.7 --- NK1 receptor antagonist --- p.63 / Chapter 3.1.2.8 --- Potassium channel inhibitor --- p.64 / Chapter 3.1.2.9 --- "Combination of cyclo-oxygenase inhibitor, nitric oxide synthase inhibitor and CGRP1 receptor antagonist" --- p.64 / Chapter 3.1.3 --- Antagonists on water-soluble fraction of Danshen --- p.91 / Chapter 3.1.3.1 --- Nitric oxide synthase inhibitor --- p.91 / Chapter 3.1.3.2 --- Cyclo-oxygenase inhibitors --- p.91 / Chapter 3.1.3.3 --- CGRP1 receptor antagonist --- p.92 / Chapter 3.1.3.4 --- NK1 receptor antagonist --- p.92 / Chapter 3.1.3.5 --- Potassium channel inhibitor --- p.92 / Chapter 3.2 --- Danshen on Rat Femoral Artery --- p.99 / Chapter 3.2.1 --- Danshen on precontracted arterial ring --- p.99 / Chapter 3.2.2 --- Endothelium-dependent mechanisms --- p.106 / Chapter 3.2.3 --- Endothelium-independent mechanisms --- p.114 / Chapter 3.2.4 --- K+ channel blockers --- p.119 / Chapter 3.2.4.1 --- Effect on Danshen --- p.119 / Chapter 3.2.4.2 --- Effect on water-soluble and lipid-soluble fractions of Danshen --- p.121 / Chapter 3.2.4.3 --- Effect on Danshensu --- p.122 / Chapter 3.2.5 --- Danshen on Ca2+-induced contractions --- p.133 / Chapter CHAPTER 4 --- DISCUSSION --- p.138 / Chapter 4.1 --- In Vivo Studies of Danshen on Rat Knee Joint Blood Flow --- p.139 / Chapter 4.2 --- In Vitro Studies of Danshen on Isolated Rat Femoral Artery --- p.148 / Chapter 4.2.1 --- Comparisons of the use of different precontractors --- p.148 / Chapter 4.2.2 --- Investigations on endothelium-dependent mechanisms --- p.151 / Chapter 4.2.3 --- Investigations on endothelium-independent mechanisms --- p.152 / Chapter 4.2.4 --- Effects of K+ channel blockers --- p.154 / Chapter 4.2.5 --- Inhibition of Ca2+ influx in vascular smooth muscle --- p.157 / Chapter 4.3 --- Comparisons of Results from In Vivo and In Vitro Studies --- p.159 / Chapter 4.4 --- Future Studies --- p.161 / Chapter 4.5 --- Conclusion --- p.162 / REFERENCES --- p.164
113

Flow mediated dilatation in Chinese type 2 diabetic patients with nephropathy. / CUHK electronic theses & dissertations collection

January 2006 (has links)
Background. Diabetes mellitus is a complex metabolic disorder characterized by clustering of multiple cardiovascular risk factors. Diabetic albuminuria is associated with increased prevalence of both micro-vascular and macro-vascular complications. This thesis examined vascular function (Flow-mediated dilatation, FMD) in type 2 diabetic patients with particular emphasis on its relationships with nephropathy. Independent predictors for FMD in Chinese population using data from both diabetic and non-diabetic subjects as well as the predictive value of FMD on clinical endpoints and death in type 2 diabetic patients with nephropathy were examined. / Conclusions. In Chinese subjects with or without type 2 diabetes, hyperglycaemia, hypertriglyceridemia, smoking and albuminuria were independent predictors for FMD. Type 2 diabetic subjects with overt nephropathy had impaired endothelium-dependent and endothelium-independent dilatation, suggesting vascular dysfunction beyond the endothelium. In agreement with studies from Caucasians, smoking was the most important determinant for vascular dysfunction in Chinese type 2 diabetic patients with overt nephropathy. Furthermore, FMD was predictive of new onset of cardiovascular events and related death in Chinese type 2 diabetic patients with overt nephropathy. / In diabetic patients with overt nephropathy, smoking (current and ex-smokers), waist hip ratio (WHR) and serum creatinine were independent predictors for impaired FMD. The latter was predictive of advancement of IMT and was an independent predictor for new onset of combined cardiovascular diseases and related death after a follow up period of 42 months (log rank test=6.04, p=0.014 using Cox regression analysis) after controlling for all confounding factors. In addition, fasting total cholesterol and plasma glucose were predictive for all-cause mortality while serum creatinine predicted new onset of renal endpoint. In a subgroup analysis in diabetic patients with overt nephropathy, smokers who developed CVD or ESRD had greater diminution of FMD than those who did not develop clinical endpoints. / Methods and results. FMD was assessed using high-resolution ultrasound scan. In the cross-sectional study, the sample population was divided into four groups according to the presence or absence of type 2 diabetes and level of albuminuria. They included the non-diabetic group (N=52), diabetic group with normoalbuminuria (N=18), diabetic group with microalbuminuria (N=18) and diabetic group with overt nephropathy defined as macroalbuminuria and renal insufficiency (N=22). Compared to non-diabetic subjects, type 2 diabetic subjects with nephropathy had impaired FMD (4.54% +/- 2.25 vs. 2.50% +/- 2.31, p<0.05) and impaired GTN-dependent dilatation (GTND) (14.30% +/- 3.77 vs. 12.70% +/- 4.70, p<0.05). They also had reduced endothelium-dependent dilatation to endothelium-independent dilatation ratio when compared to non-diabetic subjects (0.19 +/- 0.17 vs. 0.32 +/- 0.15, p<0.05). These findings suggest that the impaired vascular dilatation was due to dysfunction of both endothelium and vascular smooth muscle cells. In the entire cohort, fasting plasma glucose, fasting triglyceride, smoking and albuminuria were independent predictors for FMD. / Lai Wai Keung Christopher. / "February 2006." / Source: Dissertation Abstracts International, Volume: 67-11, Section: B, page: 6298. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2006. / Includes bibliographical references (p. 202-252). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts in English and Chinese. / School code: 1307.
114

La gestion de la charge mentale des contrôleurs aériens en-route : apports de l'eye-tracking dans le cadre du projet européen SESAR / Management of air-traffic controller's mental workload : the contribution of the eye-trcking technique within the SESAR European project

Martin, Caroline 06 September 2013 (has links)
Les contrôleurs du trafic aérien ou « aiguilleurs du ciel », dont l’activité consiste à assurer la sécurité de l’écoulement du trafic aérien, vont bientôt être confrontés à une évolution sans précédent de leur activité de travail. Pour pallier à une évolution de contexte, associée principalement à une augmentation significative du niveau de trafic aérien, la construction d’un nouvel environnement de contrôle induisant l’introduction de nouvelles technologies et de l’automatisation partielle de la tâche de contrôle est visée. Ces perspectives, qui ont pour objectif de diminuer les sollicitations des contrôleurs aériens afin d’augmenter le seuil capacitaire de gestion du trafic aérien, suscitent l’interrogation. Notamment, comment assurer la validation de ces évolutions en vue des objectifs visés ? Ce doctorat porte sur l’étude de la charge mentale de contrôleurs aériens dans différents contextes, afin d’évaluer les effets engendrés par de telles modifications apportées à leur environnement de travail quotidien. L’évaluation proposée repose sur une approche multidimensionnelle centrée sur l’analyse de paramètres oculaires enregistrés grâce à une technique d’eye-tracking dans des situations de contrôle écologiquement valides, en référence à la tâche de contrôle du trafic aérien. La première étude a tout d’abord permis de caractériser la gestion de la charge mentale effectuée par les contrôleurs aériens au cours de leur activité dans une situation nominale (reflétant la situation de contrôle du trafic aérien actuelle). La deuxième étude porte sur les effets générés par l’introduction de nouveaux systèmes informatisés d’aide à la décision induisant une automatisation partielle de la tâche de contrôle. Enfin, la dernière étude souligne l’effet du niveau de formation sur les modes de gestion des ressources cognitives employés par les contrôleurs aériens. / The air traffic controllers, whose job is to ensure the safety of air traffic flow, will soon be faced to an unprecedented change in their work activity. To compensate a change of context, mainly associated with a significant increase of the air traffic density, the elaboration of a new air traffic control environment is considered. In particular, the introduction of new technologies (all electronic devices) causing the partial automation of the control task, has been defined as prospects for the En-Route air traffic control work position. These perspectives aim at reducing the air traffic controllers’ requirements in order to increase the capability threshold of air traffic management associated with air traffic control service rendered. Such a change may however query. Indeed, how to ensure the validation of these developments to the objectives? This research aims to study the air traffic controllers’ mental workload in different contexts. The objective of this approach is to assess the effects caused by such changes in the air traffic controllers’ daily work environment. The proposed assessment is based on a multidimensional approach mainly focused on the analysis of ocular parameters recorded through an eye-tracking technique in air traffic control situations ecologically valid with reference to the features of air traffic control task. The results deduced from the empirical work of this research were first used to characterize the management of mental workload carried by air traffic controllers during their activity in the nominal situation (reflecting the current air traffic control situation). The results obtained through this research also focused on the effects generated by the introduction of new computerized systems inducing a partial automation of the control task, and those induced by the level of training dedicated to the use of such systems on the management methods of cognitive resources employed by air traffic controllers.
115

Effects of thromboxane A₂ receptor activation and periadventitial fat on cyclic GMP-dependent vaso-relaxation.

January 2007 (has links)
Ho, Kwok Wa. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2007. / Includes bibliographical references (leaves 60-65). / Abstracts in English and Chinese. / Chapter Chapter I / Chapter 1.1. --- Thromboxane A2 (TP) Receptors --- p.1 / Chapter 1.1.1. --- Gene structure of human TP receptors --- p.1 / Chapter 1.1.2. --- Isoforms of TP receptor --- p.1 / Chapter 1.1.3. --- Distribution and expression of TP receptors in human --- p.2 / Chapter 1.1.4. --- Signal transduction of TP receptors --- p.4 / Chapter 1.1.5. --- Major agonists of TP receptor in animals and humans --- p.7 / Chapter 1.1.5.1. --- Thromboxane A2 --- p.7 / Chapter 1.1.5.2. --- Prostaglandin H2 --- p.7 / Chapter 1.1.6. --- Functional studies: effect of TP receptor activation and blockade on vascular tone and atherosclerosis --- p.8 / Chapter 1.1.6.1. --- Effect of TP receptor activation --- p.8 / Chapter 1.1.6.1.1. --- On vaso-contraction --- p.8 / Chapter 1.1.6.1.2. --- On vaso-relaxation --- p.9 / Chapter 1.1.6.2. --- Effect of TP receptor blockade --- p.9 / Chapter 1.1.6.2.1. --- On endothelium dependent vaso-contraction --- p.9 / Chapter 1.1.6.2.2. --- On animal models related to atherosclerosis --- p.10 / Chapter 1.1.7. --- Objectives of current study --- p.10 / Chapter 1.2. --- Periadventitial Adipose (Fat) Tissue --- p.12 / Chapter 1.2.1. --- "General function, distribution and classification of fat" --- p.12 / Chapter 1.2.2. --- Representative endocrine/paracrine role of adipose tissues --- p.13 / Chapter 1.2.2.1. --- Leptin --- p.13 / Chapter 1.2.2.2. --- Angiotensinogen --- p.14 / Chapter 1.2.3. --- Functional studies on vessels with periadventital fat attached -The beginning of the story of adipcyte-derived relaxing factor (ADRF) --- p.15 / Chapter 1.2.3. --- Mechanisms behind the action of ADRF --- p.17 / Chapter 1.2.3.1. --- Nature of ADRF --- p.17 / Chapter 1.2.3.2. --- The mechanisms controlling the release of ADRF --- p.17 / Chapter 1.2.3.3. --- Proposed mechanisms explaining the anti-contractile effect mediated by ADRF --- p.17 / Chapter 1.2.4. --- Objectives of current study --- p.20 / Chapter Chapter II / Chapter 2.1. --- Tissue Preparation --- p.21 / Chapter 2.1.1. --- Preparation of blood vessels --- p.21 / Chapter 2.1.2. --- Procedures to remove the endothelium --- p.21 / Chapter 2.2. --- The Organ Bath Setups --- p.22 / Chapter 2.3. --- Calculation of Results --- p.24 / Chapter 2.3.1. --- Calculation of active tension --- p.24 / Chapter 2.3.2. --- Measurement of dry weight of arterial rings --- p.24 / Chapter 2.3.3. --- Measurement of the weight for periadventitial fat --- p.24 / Chapter 2.3.4. --- Statistic analysis --- p.24 / Chapter 2.4. --- Chemicals and Solutions --- p.25 / Chapter 2.4.1. --- Chemicals --- p.25 / Chapter 2.4.2. --- Solutions --- p.26 / Chapter Chapter III --- Stimulation of TP receptors by U46619 inhibits cGMP dependent vaso-relaxation --- p.27 / Chapter 3.1. --- Detail methods and materials --- p.27 / Chapter 3.1.1. --- "Safety announcement, tissue preparation and materials" --- p.27 / Chapter 3.1.1. --- Protocol --- p.27 / Chapter 3.1.1.1. --- PartI --- p.27 / Chapter 3.1.1.2. --- Part II --- p.28 / Chapter 3.1.1.3. --- Part III --- p.28 / Chapter 3.2. --- Results --- p.29 / Chapter 3.2.1. --- Effect of U46619 on vaso-relaxation --- p.29 / Chapter 3.2.2. --- Effect of Rho kinase and phosphodiesterase inhibitor on the inhibitory effect of U46619 --- p.29 / Chapter 3.2.3. --- The effect of low concentration of U46619 on vaso-relaxation --- p.29 / Chapter 3.3. --- Discussion --- p.37 / Chapter 3.3.1. --- Implication of the current study --- p.37 / Chapter 3.3.2. --- Formulated Theory --- p.41 / Chapter Chapter IV --- Effect of periadventitial fat on anti-relaxation effect induced by U46619 - A preliminary test --- p.43 / Chapter 4.1. --- Detail methods and materials --- p.43 / Chapter 4.1.1. --- "Safety announcement, tissue preparation and materials" --- p.43 / Chapter 4.1.2. --- Protocol --- p.43 / Chapter 4.1.2.1. --- Part I --- p.43 / Chapter 4.1.2.2. --- Part II --- p.44 / Chapter 4.1.2.3. --- Part III --- p.44 / Chapter 4.1.2.4. --- Part IV --- p.44 / Chapter 4.2. --- Results --- p.45 / Chapter 4.2.1. --- Effect of periadventitial fat on vaso-relaxation of rings contracted by phenylephrine --- p.45 / Chapter 4.2.2. --- Effect of periadventitial fat on vaso-relaxation of rings contracted by U46619 plus phenylephrine --- p.45 / Chapter 4.2.3. --- Effect of S18886 on vaso-relaxation in endothelium removed rings --- p.45 / Chapter 4.2.4. --- Effect of elevated extracellular potassium ions on vaso-relaxation --- p.46 / Chapter 4.3. --- Discussion --- p.56 / Chapter 4.3.1. --- Implication of current study --- p.56 / Chapter 4.3.2. --- Improvements and future perspectives of current study --- p.58 / Summary --- p.59 / References --- p.60
116

Géométrie et topologie des processus périodiquement corrélés induit par la dilation : Application à l'étude de la variabilité des épidémies pédiatriques saisonnières / Geometry and topology of periodically correlated processes : Analysis of the variability of seasonal pediatric epidemics

Dugast, Maël 21 December 2018 (has links)
Chaque année lors de la période hivernale, des phénomènes épidémiques affectent l’organisation des services d’urgences pédiatriques et dégradent la qualité de la réponse fournie. Ces phénomènes présentent une forte variabilité qui rend leur analyse difficile. Nous nous proposons d’étudier cette volatilité pour apporter une vision nouvelle et éclairante sur le comportement de ces épidémies. Pour ce faire, nous avons adopté une vision géométrique et topologique originale directement issue d’une application de la théorie de la dilation: le processus de variabilité étant périodiquement corrélé, cette théorie fournit un ensemble de matrices dites de dilations qui portent toute l’information utile sur ce processus. Cet ensemble de matrices nous permet de représenter les processus stochastiques comme des éléments d’un groupe de Lie particulier, à savoir le groupe de Lie constitué de l’ensemble des courbes sur une variété. Il est alors possible de comparer des processus par ce biais. Pour avoir une perception plus intuitive du processus de variabilité, nous nous sommes ensuite concentrés sur le nuage de points formé par l’ensemble des matrices de dilations. En effet, nous souhaitons mettre en évidence une relation entre la forme temporelle d’un processus et l’organisation de ces matrices de dilations. Nous avons utilisé et développé des outils d’homologie persistante et avons établi un lien entre la désorganisation de ce nuage de points et le type de processus sous-jacents. Enfin nous avons appliqué ces méthodes directement sur le processus de variabilité pour pouvoir détecter le déclenchement de l’épidémie. Ainsi nous avons établi un cadre complet et cohérent, à la fois théorique et appliqué pour répondre à notre problématique. / Each year emergency department are faced with epidemics that affect their organisation and deteriorate the quality of the cares. The analyse of these outbreak is tough due to their huge variability. We aim to study these phenomenon and to bring out a new paradigm in the analysis of their behavior. With this aim in mind, we propose to tackle this problem through geometry and topology: the variability process being periodically correlated, the theory of dilation exhibit a set of matrices that carry all the information about this process. This set of matrices allow to map the process into a Lie group, defined as the set of all curves on a manifold. Thus, it is possible to compare stochastic processes using properties of Lie groups. Then, we consider the point cloud formed by the set of dilation matrices, to gain more intuitions about the underlying process. We proved a relation between the temporal aspect of the signal and the structure of the set of its dilation matrices. We used and developped persistent homology tools, and were able to classify non-stationary processes. Eventually, we implement these techniques directly on the process of arrivals to detect the trigger of the epidemics. Overall we established a complete and a coherent framework, both theoretical and practical.
117

Atomes de Rydberg en champ micro-onde : régularité et chaos

Buchleitner, Andreas 13 December 1993 (has links) (PDF)
Nous développons un formalisme théorique qui fournit un outil puissant pour l'analyse numérique détaillée de l'interaction d'un atome d'hydrogène tridimensionnel avec un champ de rayonnement intense. L'application de cette approche à l'ionisation des états de Rydberg de l'atome d'hydrogène par une micro-onde constitue l'expérience numérique la plus réaliste jamais réalisée dans ce domaine. Pour un modèle unidimensionnel de l'atome, nous effectuons une analyse approfondie des signaux et des seuils d'ionisation, de la dynamique des niveaux et des projections des fonctions d'onde associées sur l'espace des phases. Une comparaison avec l'ionisation de l'atome réel tridmensionnel confirme la validité du modèle unidimensionnel et ainsi de la théorie de la localisation dynamique pour les états initiaux étendus, tant que le seuil d'ionisation est concerné. Trois classes d'états initiaux tridimensionels sont identifiés, avec des symétries distinctes, s'adaptant plus ou moins bien aux symétries des états propres du problème microonde. Nous montrons quelques "cicatrices" de fonctions d'onde de l'hydrogène exposé à un champ micro-onde. Finalement, la dynamique d'un état circulaire dans un champ micro-onde et celle dans un champ laser ultra-intense sont comparées.
118

Caractérisation thermique et thermomécanique de fibres de carbone et céramique à très haute température

Pradere, Christophe 09 1900 (has links) (PDF)
Ce travail, motivé par un besoin industriel, a pour objectif de déterminer les propriétés thermiques et thermomécaniques de fibres micrométriques de carbone et céramique à très haute température (1000-3000 K). Afin de fournir des mesures à de telles échelles et sur une telle gamme de température, notre étude a porté sur: la modélisation des phénomènes, le développement de méthodes d'identification stables, l'optimisation expérimentale et la recherche d'erreurs. En plus de ce travail important de développement de méthodes de mesures, un effort particulier a consisté à réaliser un maximum de caractérisations susceptibles d'apporter une connaissance précise des propriétés thermiques et thermomécaniques (inconnues jusqu'à présent) des fibres de carbone. Dans la première partie, relative à la détermination des propriétés thermomécaniques des fibres, la difficulté peut se résumer à la mise en oeuvre de méthodes susceptibles de détecter avec précision, à très haute température, des variations de l'ordre de quelques nanomètres sur des matériaux dont la dimension caractéristique est d'environ 10 mm. La méthode développée permet de réaliser indifféremment des mesures du coefficient de dilatation transverse et du coefficient de Poisson. Dans la deuxième partie, on détermine d'une part la capacité thermique massique à pression constante à l'aide d'une méthode analytique et d'autre part la diffusivité thermique longitudinale par méthode inverse, ce qui nous permet d'estimer la conductivité thermique. Dans les deux cas, la difficulté liée aux échelles micrométriques et aux très hautes températures se répercute sur l'expérimentation, sur les modélisations et sur le développement de méthodes d'identifications.
119

Composites aluminium/fibres de carbone pour l'électronique de puissance

Lalet, Grégory 24 September 2010 (has links) (PDF)
L'étude a pour objectif l'amélioration de la fiabilité des assemblages électroniques à travers la mise en œuvre de drains composites aluminium/fibres de carbone. Le travail a consisté à 1) modéliser, par la méthode des éléments finis, l'influence des propriétés thermiques et mécaniques du matériau de semelle sur l'assemblage életronique ; 2) élaborer (par frittage sous charge uniaxiale, frittage flash et extrusion à chaud) des matériaux composites aluminium/fibres de carbone ; et 3) lier les microstructures observées aux paramètres des procédés d'élaboration ainsi qu'aux propriétés thermiques et mécaniques mesurées.
120

Frottement saccadé dans les matériaux granulaire modèles

Hoang, Minh Tam 08 July 2011 (has links) (PDF)
Cette étude a pour objectifs la caractérisation expérimentale des frottements saccadés dans les matériaux granulaires modèles constitués des billes de verre monodisperses en compression triaxiale drainée et l'identification des paramètres de contrôle. Cinq paramètres macroscopiques caractérisent ces frottements saccadés : la chute de déviateur et la contraction volumique, l'intermittence de déformation axiale, le module d'Young et le coefficient de Poisson. Les frottements saccadés affectent simultanément le déviateur et la déformation volumique. Le comportement macroscopique est globalement contractant tandis que le matériau tend vers un état limite critique en grandes déformations, à la manière des sables lâches. Cependant il présente localement, dans les phases de blocage qui suivent immédiatement les ruptures temporaires, le comportement dilatant des sables denses, qui obéit à une relation contrainte-dilatance linéaire et unique. Les frottements saccadés disparaissent au-delà d'une vitesse critique d'écrasement axial, qui dépend de la contrainte de confinement et de la taille des grains. Le module d'Young dynamique par propagation d'ondes varie avec la contrainte de confinement selon une loi de puissance. Le module d'Young quasi-élastique au départ des phases de blocage est constant à l'intérieur du domaine élastique, de même que le coefficient de Poisson. Le suivi par granulométrie laser et par analyse d'images des matériaux après un ou plusieurs essais triaxiaux permet de suivre l'évolution de la taille moyenne et de la forme des grains. Tandis que les instabilités par saccade disparaissent suite à un certain nombre d'essais, on observe, simultanément à une légère diminution du volume moyen, l'apparition progressive de populations d'objets non sphériques par une fusion des grains analogue au frittage.

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